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Sample records for 18oh2o control valve

  1. Cavitation guide for control valves

    Energy Technology Data Exchange (ETDEWEB)

    Tullis, J.P. [Tullis Engineering Consultants, Logan, UT (United States)

    1993-04-01

    This guide teaches the basic fundamentals of cavitation to provide the reader with an understanding of what causes cavitation, when it occurs, and the potential problems cavitation can cause to a valve and piping system. The document provides guidelines for understanding how to reduce the cavitation and/or select control valves for a cavitating system. The guide provides a method for predicting the cavitation intensity of control valves, and how the effect of cavitation on a system will vary with valve type, valve function, valve size, operating pressure, duration of operation and details of the piping installation. The guide defines six cavitation limits identifying cavitation intensities ranging from inception to the maximum intensity possible. The intensity of the cavitation at each limit Is described, including a brief discussion of how each level of cavitation influences the valve and system. Examples are included to demonstrate how to apply the method, including making both size and pressure scale effects corrections. Methods of controlling cavitation are discussed providing information on various techniques which can be used to design a new system or modify an existing one so it can operate at a desired level of cavitation.

  2. Microprocessor-Based Valved Controller

    Science.gov (United States)

    Norman, Arnold M., Jr.

    1987-01-01

    New controller simpler, more precise, and lighter than predecessors. Mass-flow controller compensates for changing supply pressure and temperature such as occurs when gas-supply tank becomes depleted. By periodically updating calculation of mass-flow rate, controller determines correct new position for valve and keeps mass-flow rate nearly constant.

  3. Improving the pneumatic control valve performance using a PID controller

    OpenAIRE

    Heidari, Mohammad; Homaei, Hadi

    2014-01-01

    Pneumatic control valves are still the most used in process industries due to their low cost and simplicity. This paper presents a design procedure of a PID controller for a pneumatic control valve. For comparison, P and PI controllers are also utilized for the control valve. The bond graph method is used to model the control valve, in order to compare the response characteristics of the valve. Simulation results are found for three controllers of the valve. The integral time absolute error c...

  4. Novel Active Combustion Control Valve

    Science.gov (United States)

    Caspermeyer, Matt

    2014-01-01

    This project presents an innovative solution for active combustion control. Relative to the state of the art, this concept provides frequency modulation (greater than 1,000 Hz) in combination with high-amplitude modulation (in excess of 30 percent flow) and can be adapted to a large range of fuel injector sizes. Existing valves often have low flow modulation strength. To achieve higher flow modulation requires excessively large valves or too much electrical power to be practical. This active combustion control valve (ACCV) has high-frequency and -amplitude modulation, consumes low electrical power, is closely coupled with the fuel injector for modulation strength, and is practical in size and weight. By mitigating combustion instabilities at higher frequencies than have been previously achieved (approximately 1,000 Hz), this new technology enables gas turbines to run at operating points that produce lower emissions and higher performance.

  5. Advantages with small control valves

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, Gunnar

    2008-09-15

    Between 1995 and 2005, the Swedish District Heating Association carried out several research projects concerning small dimensions on control valves. This lecture aims at giving a summary of these findings which, if they are carried out, have a great impact on the district heating system. The outcome is advantages on both the production side and the customer side. Some of the project's conclusions are as follows: 1. The simulations show that the consequences of temperature disturbances can be reduced when applying smaller control valves, especially at low outdoor temperatures (-5 deg C). 2. The consequences of flow disturbances (pump stop) are not depending on the outdoor temperature (heat demand), but results over the whole year in reduced maximum flow during the process of operation recovery. With adequately reduced valve size, the resulting maximum flow at restart can be approximately reduced to the half, leading in reduced need of pumping peak power. 3. Similarly, the maximum peak power taken from the net at net recovery will be reduced, however, this effect is not as strong as that for flow. 4. Generally, we have found clear indications for that the adjustment of the K{sub vs}-values of control valves in substations should follow a certain logical order of priority. An important factor is the location of substations in respect to the production plant and to the pressure control points in the network. Another important factor is the absolute K{sub vs}-value of the over sizing, i.e. the difference of the actual installed valve and the targeted valve size. 5. Smaller size of control valves means also an improvement of the everyday operation of the district heating net, especially in the case when flow and power peaks are expected to occur. Examples for that could be the morning peaks with increase heat and hot water demands, or such events when the air temperature is decreasing very fast because of weather phenomena. Smaller control valves will smear out the

  6. Hydraulic engine valve actuation system including independent feedback control

    Science.gov (United States)

    Marriott, Craig D

    2013-06-04

    A hydraulic valve actuation assembly may include a housing, a piston, a supply control valve, a closing control valve, and an opening control valve. The housing may define a first fluid chamber, a second fluid chamber, and a third fluid chamber. The piston may be axially secured to an engine valve and located within the first, second and third fluid chambers. The supply control valve may control a hydraulic fluid supply to the piston. The closing control valve may be located between the supply control valve and the second fluid chamber and may control fluid flow from the second fluid chamber to the supply control valve. The opening control valve may be located between the supply control valve and the second fluid chamber and may control fluid flow from the supply control valve to the second fluid chamber.

  7. VOST Flow-Control Valve Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A cryogenic flow-control valve based on Venturi-Offset Technology (VOST) will be designed and modeled. VOST provides precise linear flow control within a...

  8. VOST Flow-Control Valve Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Two cryogenic flow-control valves of diameters 1/2" and 2" will be built and tested. Based on cryogenically-proven Venturi Off-Set Technology (VOST) they have no...

  9. Simulation of a Hydraulic Pump Control Valve

    Science.gov (United States)

    Molen, G. Vander; Akers, A.

    1987-01-01

    This paper describes the mode of operation of a control valve assembly that is used with a hydraulic pump. The operating system of the valve is modelled in a simplified form, and an analogy for hydraulic resonance of the pressure sensing system is presented. For the control valve investigated, air entrainment, length and diameter of the resonator neck, and valve mass produced the greatest shift in resonant frequency. Experimental work was conducted on the hydraulic system so that the resonance levels and frequencies could be measured and the accuracy of the theory verified. The results obtained make it possible to evaluate what changes to any of the variables considered would be most effective in driving the second harmonic frequency above the operating range.

  10. Electromechanically Actuated Valve for Controlling Flow Rate

    Science.gov (United States)

    Patterson, Paul

    2007-01-01

    A proposed valve for controlling the rate of flow of a fluid would include an electric-motor-driven ball-screw mechanism for adjusting the seating element of the valve to any position between fully closed and fully open. The motor would be of a type that can be electronically controlled to rotate to a specified angular position and to rotate at a specified rate, and the ball screw would enable accurate linear positioning of the seating element as a function of angular position of the motor. Hence, the proposed valve would enable fine electronic control of the rate of flow and the rate of change of flow. The uniqueness of this valve lies in a high degree of integration of the actuation mechanism with the flow-control components into a single, relatively compact unit. A notable feature of this integration is that in addition to being a major part of the actuation mechanism, the ball screw would also be a flow-control component: the ball screw would be hollow so as to contain part of the main flow passage, and one end of the ball screw would be the main seating valve element. The relationships among the components of the valve are best understood by reference to the figure, which presents meridional cross sections of the valve in the fully closed and fully open positions. The motor would be supported by a bracket bolted to the valve body. By means of gears or pulleys and a timing belt, motor drive would be transmitted to a sleeve that would rotate on bearings in the valve body. A ball nut inside the sleeve would be made to rotate with the sleeve by use of a key. The ball screw would pass through and engage the ball nut. A key would prevent rotation of the ball screw in the valve body while allowing the ball screw to translate axially when driven by the ball nut. The outer surface of the ball screw would be threaded only in a mid-length region: the end regions of the outer surface of the ball screw would be polished so that they could act as dynamic sealing surfaces

  11. STUDY ON FLUID THICKNESS BETWEEN POPPET AND VALVE GUIDE IN CONTROL VALVE OF INJECTOR

    Institute of Scientific and Technical Information of China (English)

    Zhang Jianming; Zhang Weigang; Wang Yawei

    2004-01-01

    The physical model of -20 diesel oil and force model of injector control valve of common rail system is built. The changes of the fluid thickness are investigated on the base of the results of CFD and experiments for control valve of injector. The results indicate that a fluid thickness of 0.02~0.03 mm between the poppet and valve guide is sufficient to dampen any excessive control valve poppet bouncing.

  12. Exhaust gas bypass valve control for thermoelectric generator

    Science.gov (United States)

    Reynolds, Michael G; Yang, Jihui; Meisner, Greogry P.; Stabler, Francis R.; De Bock, Hendrik Pieter Jacobus; Anderson, Todd Alan

    2012-09-04

    A method of controlling engine exhaust flow through at least one of an exhaust bypass and a thermoelectric device via a bypass valve is provided. The method includes: determining a mass flow of exhaust exiting an engine; determining a desired exhaust pressure based on the mass flow of exhaust; comparing the desired exhaust pressure to a determined exhaust pressure; and determining a bypass valve control value based on the comparing, wherein the bypass valve control value is used to control the bypass valve.

  13. 46 CFR 108.443 - Controls and valves.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Controls and valves. 108.443 Section 108.443 Shipping... valves. (a) At least one control for operating a CO2 system must be outside the space or spaces that the... system protects. Control valves must not be located in a protected space unless the CO2 cylinders...

  14. Fluid damping clearance in a control valve of injector

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jianming; ZHANG Weigang; YANG Bing; WANG Yawei

    2007-01-01

    A force model of a control valve of injector is set up, and the changes of the fluid damping clearance are investigated on the basis of the results of the computational fluid dynamics (CFD) and the experiments of control valve of injector. Results indicate that a damping clearance of 0.02-0.03 mm between the poppet and the valve guide is the most sufficient to dampen any excessive control valve poppet bouncing.

  15. 14 CFR 23.995 - Fuel valves and controls.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel valves and controls. 23.995 Section 23... Components § 23.995 Fuel valves and controls. (a) There must be a means to allow appropriate flight crew members to rapidly shut off, in flight, the fuel to each engine individually. (b) No shutoff valve may...

  16. Active Combustion Control Valve Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Over the past decade, research into active combustion control has yielded impressive results in suppressing thermoacoustic instabilities and widening the...

  17. Active Combustion Control Valve Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Over the past decade, research into active combustion control has yielded impressive results in suppressing thermoacoustic instabilities and widening the operational...

  18. Quadratic Optimal Regulator Design of a Pneumatic Control Valve

    Directory of Open Access Journals (Sweden)

    Mohammad Heidari

    2013-01-01

    Full Text Available Pneumatic control valves are still the most used devices in the process industries, due to their low cost and simplicity. This paper presents a regulator for pneumatic control valves using pole-placement method, optimal control, full-order state observer, and minimum-order state observer and their responses will be compared with each other. Bondgraph method has been used to model the control valve. Simulation results have been made for four models of regulator. The results show that minimum overshoot and settling time are achieved using optimal regulator of pneumatic valve.

  19. 49 CFR 393.49 - Control valves for brakes.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Control valves for brakes. 393.49 Section 393.49... NECESSARY FOR SAFE OPERATION Brakes § 393.49 Control valves for brakes. (a) General rule. Except as provided..., which is equipped with power brakes, must have the braking system so arranged that one application...

  20. System and method for controlling engine knock using electro-hydraulic valve actuation

    Science.gov (United States)

    Brennan, Daniel G

    2013-12-10

    A control system for an engine includes a knock control module and a valve control module. The knock control module adjusts a period that one or more of an intake valve and an exhaust valve of a cylinder are open based on engine knock corresponding to the cylinder. The valve control module, based on the adjusted period, controls the one or more of the intake valve and the exhaust valve using one or more hydraulic actuators.

  1. Pressure control valve using proportional electro-magnetic solenoid actuator

    Energy Technology Data Exchange (ETDEWEB)

    Yun, So Nam; Ham, Young Bog; Park, Pyoung Won [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2006-10-15

    This paper presents an experimental characteristics of electro-hydraulic proportional pressure control valve. In this study, poppet and valve body which are assembled into the proportional solenoid were designed and manufactured. The constant force characteristics of proportional solenoid actuator in the control region should be independent of the plunger position in order to be used to control the valve position in the fluid flow control system. The stroke-force characteristics of the proportional solenoid actuator is determined by the shape (or parameters) of the control cone. In this paper, steady state and transient characteristics of the solenoid actuator for electro-hydraulic proportional valve are analyzed using finite element method and it is confirmed that the proportional solenoid actuator has a constant attraction force in the control region independently on the stroke position. The effects of the parameters such as control cone length, thickness and taper length are also discussed.

  2. Pneumatic jet-control valve for dual circulating fluidized beds

    Science.gov (United States)

    Jiang, Haibo; Dong, Pengfei; Zhu, Zhiping; Wang, Kun; Zhang, Yukui; Lu, Qinggang

    2015-11-01

    With the rapid development of circulating fluidized bed (CFB) technology in different fields, the disadvantages of conventional non-mechanical valves are becoming more apparent, and they are not suitable to be used in complex CFB systems. In this paper, a novel non-mechanical valve named the jet-control valve is presented which can avoid the fluidization of solid particles. The feasibility and performance characteristics of the new valve are investigated with a cold-model dual CFB. The results show that compared with the conventional non-mechanical valve, the jet-control valve can transfer solid particles steadily over a larger range, prevent artesian flow, and improve the leakage characteristics. The effects of the operating parameters and structural parameters on the minimum aeration velocity, solid flow rate, and maximum solid flow rate are studied. A two-valve model is proposed to explain the transport capacity of the valve for one jet pipe. A semi-theoretical expression is obtained based on the experimental data with a maximum deviation of 30% providing useful guide for scaling-up the design.

  3. Controlling the cavitation phenomenon of evolution on a butterfly valve

    Science.gov (United States)

    Baran, G.; Catana, I.; Magheti, I.; Safta, C. A.; Savu, M.

    2010-08-01

    Development of the phenomenon of cavitation in cavitation behavior requires knowledge of both plant and equipment working in the facility. This paper presents a diagram of cavitational behavior for a butterfly valve with a diameter of 100 mm at various openings, which was experimentally built. We proposed seven stages of evolution of the phenomenon of cavitation in the case of a butterfly valve. All these phases are characterized by pressure drop, noise and vibration at various flow rates and flow sections through the valve. The level of noise and vibration for the seven stages of development of the phenomenon of cavitation were measured simultaneously. The experimental measurements were comprised in a knowledge database used in training of a neural network of a neural flow controller that maintains flow rate constantly in the facility by changing the opening butterfly valve. A fuzzy position controller is used to access the valve open. This is the method proposed to provide operational supervision outside the cavitation for a butterfly valve.

  4. System and method for controlling hydraulic pressure in electro-hydraulic valve actuation systems

    Energy Technology Data Exchange (ETDEWEB)

    Brennan, Daniel G; Marriott, Craig D; Cowgill, Joel; Wiles, Matthew A; Patton, Kenneth James

    2014-09-23

    A control system for an engine includes a first lift control module and a second lift control module. The first lift control module increases lift of M valves of the engine to a predetermined valve lift during a period before disabling or re-enabling N valves of the engine. The second lift control module decreases the lift of the M valves to a desired valve lift during a period after enabling or re-enabling the N valves of the engine, wherein N and M are integers greater than or equal to one.

  5. Pressure tracking control of vehicle ABS using piezo valve modulator

    Science.gov (United States)

    Jeon, Juncheol; Choi, Seung-Bok

    2011-03-01

    This paper presents a wheel slip control for the ABS(anti-lock brake system) of a passenger vehicle using a controllable piezo valve modulator. The ABS is designed to optimize for braking effectiveness and good steerability. As a first step, the principal design parameters of the piezo valve and pressure modulator are appropriately determined by considering the braking pressure variation during the ABS operation. The proposed piezo valve consists of a flapper, pneumatic circuit and a piezostack actuator. In order to get wide control range of the pressure, the pressure modulator is desired. The modulator consists of a dual-type cylinder filled with different substances (fluid and gas) and a piston rod moving vertical axis to transmit the force. Subsequently, a quarter car wheel slip model is formulated and integrated with the governing equation of the piezo valve modulator. A sliding mode controller to achieve the desired slip rate is then designed and implemented. Braking control performances such as brake pressure and slip rate are evaluated via computer simulations.

  6. RESEARCH ON THE PERFORMANCE OF NEW TYPE OF PROPORTIONAL PESSURE AND FLOW CONTROL VALVE

    Institute of Scientific and Technical Information of China (English)

    Quan Long; Ma Jian; Wang Yongjin

    2003-01-01

    A new closed loop flow controlling principle through correcting the valve's opening area while load pressure is changing is carried out. Further more a principle using only one proportional valve to compound control pressure and flow is suggested. By using very simple proportional throttle valve in structure, the functions that five kinds of proportional valves or any two of them combined possess can be complimented. After analyzing, comparing, and testing the dynamic and static characteristics of valve with different controlling principles and main valve structure styles, the optimized structure styles and control methods are achieved.

  7. Proportional control valves integrated in silicon nitride surface channel technology

    NARCIS (Netherlands)

    Groen, Maarten S.; Groenesteijn, Jarno; Meutstege, Esken; Brookhuis, Robert A.; Brouwer, Dannis M.; Lötters, Joost C.; Wiegerink, Remco J.

    2015-01-01

    We have designed and realized two types of proportional microcontrol valves in a silicon nitride surface channel technology process. This enables on-die integration of flow controllers with other surface channel devices, such as pressure sensors or thermal or Coriolis-based (mass) flow sensors, to o

  8. An Introduction to Controller Performance Assessment in Process Control Class through Stiction in Control Valves

    Science.gov (United States)

    Srinivasan, Ranganathan; Rengaswamy, Raghunathan; Harris, Sandra

    2007-01-01

    In this paper, we discuss a simple liquid level experiment that can be used to teach nonlinear phenomena in process control through stiction in control valves. This experiment can be used to introduce the undergraduate students to the area of Controller Performance Assessment (CPA). The experiment is very easy to set-up and demonstrate. While…

  9. Control valve and control valve system for controlling solids flow, methods of manufacture thereof and articles comprising the same

    Energy Technology Data Exchange (ETDEWEB)

    Jukkola, Glen D.; Teigen, Bard C.

    2017-04-11

    Disclosed herein is a solids flow control valve comprising a standpipe; a shoe; and a transport pipe; wherein the standpipe is in operative communication with the shoe and lies upstream of the shoe; the standpipe comprising a first end and a second end, where the first end is in contact with a source that contains disposable solids and the second end is in fluid contact with the shoe; the shoe being operative to restrict the flow of the disposable solids; the transport pipe being disposed downstream of the shoe to receive and transport the solids from the shoe.

  10. Control Valve Trajectories for SOFC Hybrid System Startup

    Energy Technology Data Exchange (ETDEWEB)

    Gorrell, Megan; Banta, Larry; Rosen, William; Restrepo, Bernardo; Tucker, David

    2012-07-01

    Control and management of cathode airflow in a solid oxide fuel cell gas turbine hybrid power system was analyzed using the Hybrid Performance (HyPer) hardware simulation at the National Energy Technology (NETL), U.S. Department of Energy. This work delves into previously unexplored operating practices for HyPer, via simultaneous manipulation of bypass valves and the electric load on the generator. The work is preparatory to the development of a Multi-Input, Multi-Output (MIMO) controller for HyPer. A factorial design of experiments was conducted to acquire data for 81 different combinations of the manipulated variables, which consisted of three air flow control valves and the electric load on the turbine generator. From this data the response surface for the cathode airflow with respect to bypass valve positions was analyzed. Of particular interest is the control of airflow through the cathode during system startup and during large load swings. This paper presents an algorithm for controlling air mass flow through the cathode based on a modification of the steepest ascent method.

  11. TRANSIENT RESPONSE OF A VALVE CONTROL HYDRAULIC SYSTEM WITHLONG PIPES

    Institute of Scientific and Technical Information of China (English)

    Wei Jianhua; Kong Xiaowu; Qiu Minxiu; Wu Genmao

    2004-01-01

    The simulation model of a valve control hydraulic system with long pipe is established in Simulink4.0, and then the step responses of the systems with difference pipe parameters are investigated by simulation.Simulation results show that the long pipes will slow down the step response of system and make it fluctuate periodically.The results of simulation conform to the results of experiment on the whole, which proves the mathematic model is correct.

  12. Development of Small-sized Fluid Control Valve with Self-holding Function Using Permanent Magnet

    Science.gov (United States)

    Akagi, Tetsuya; Dohta, Shujiro; Ueda, Hirofumi

    Recently, force feedback devices in virtual reality and power assisted nursing care systems have received much attention and active research. In such a control system, an actuator and a driving device such as a control valve are mounted on the human body. In this condition, the size and weight of the control valve become serious problems. At the same time, the valve should be operated with lower energy consumption because of using a limited electrical power. The typical electro magnetic solenoid valve drives its spool using a larger solenoid to open the valve. The complex construction of the valve for sealing makes its miniaturization and the fabrication of a low cost valve more difficult. In addition, the solenoid in the valve consumes more electrical power while the valve is kept opening. The purpose of our study is to develop a small-sized, lightweight, lower energy consumption and flexible control valve that can be safe enough to mount on the human body at a lower cost. In our pervious study, we proposed and tested the control valve that can open using a vibration motor. In this study, we propose and test a new type of fluid control valve with a self-holding function. The new valve uses a permanent magnet ball. It has a cylindrical magnet and two solenoids. The self-holding function of the valve is done as follows. When one side of the solenoid is stimulated by the current momentarily, the solenoid gives a repulsive force to the cylindrical magnet. The magnet moves toward the opposite side of the solenoid and is attracted to the iron core. Then, the magnet ball moves toward the cylindrical magnet and opens the orifice. The valve can keep open without electrical energy. As a result, the valve with the extremely lower energy consumption can be developed.

  13. Magnetic hydrogel nanocomposites as remote controlled microfluidic valves.

    Science.gov (United States)

    Satarkar, Nitin S; Zhang, Wenli; Eitel, Richard E; Hilt, J Zach

    2009-06-21

    In recent years, hydrogels have attracted attention as active components in microfluidic devices. Here, we present a demonstration of remote controlled flow regulation in a microfluidic device using a hydrogel nanocomposite valve. To create the nanocomposite hydrogel, magnetic nanoparticles were dispersed in temperature-responsive N-isopropylacrylamide (NIPAAm) hydrogels. The swelling and collapse of the resultant nanocomposite can be remotely controlled by application of an alternating magnetic field (AMF). A ceramic microfluidic device with Y-junction channels was fabricated using low temperature co-fired ceramic (LTCC) technology. The nanocomposite was incorporated as a valve in one of the channels of the device. An AMF of frequency 293 kHz was then applied to the device and ON-OFF control on flow was achieved. A pressure transducer was placed at the inlet of the channel and pressure measurements were done for multiple AMF ON-OFF cycles to evaluate the reproducibility of the valve. Furthermore, the effect of the hydrogel geometry on the response time was characterized by hydrogels with different dimensions. Magnetic hydrogel nanocomposite films of different thicknesses (0.5, 1, 1.5 mm) were subjected to AMF and the kinetics of collapse and recovery were studied.

  14. Modeling of fluid-induced vibrations and identification of hydrodynamic forces on flow control valves

    Institute of Scientific and Technical Information of China (English)

    Samad Mehrzad; Ilgar Javanshir; Ahmad Rahbar Ranji; Seyyed Hadi Taheri

    2015-01-01

    Dynamics and vibration of control valves under flow-induced vibration are analyzed. Hydrodynamic load characteristics and structural response under flow-induced vibration are mainly influenced by inertia, damping, elastic, geometric characteristics and hydraulic parameters. The purpose of this work is to investigate the dynamic behavior of control valves in the response to self-excited fluid flow. An analytical and numerical method is developed to simulate the dynamic and vibrational behavior of sliding dam valves, in response to flow excitation. In order to demonstrate the effectiveness of proposed model, the simulation results are validated with experimental ones. Finally, to achieve the optimal valve geometry, numerical results for various shapes of valves are compared. Rounded valve with the least amount of flow turbulence obtains lower fluctuations and vibration amplitude compared with the flat and steep valves. Simulation results demonstrate that with the optimal design requirements of valves, vibration amplitude can be reduced by an average to 30%.

  15. A new PROFIBUS interface for vacuum sector gate valve controllers

    Science.gov (United States)

    Pigny, G.; Ferreira, R.; Gomes, P.; Gyori, L.; Roda, M.

    2017-02-01

    The vacuum control systems of the accelerators complex at CERN are based on PLCs, which communicate with controllers either with direct inputs or outputs, or via PROFIBUS. In order to improve the efficiency of the sector valve controller communication, a low cost PROFIBUS interface card has been designed. This paper presents the developed hardware and firmware, together with the corresponding assessment tests. It flags the improvements of this new interface, in comparison with the former system. Furthermore, this paper can be helpful for any custom design that needs a PROFIBUS interface.

  16. Effect of Cone Angle on the Hydraulic Characteristics of Globe Control Valve

    Institute of Scientific and Technical Information of China (English)

    LIN Zhe; WANG Huijie; SHANG Zhaohui; CUI Baoling; ZHU Chongxi; ZHU Zuchao

    2015-01-01

    Globe control valve is widely used in chemical, petroleum and hydraulic industries, and its throttling feature is achieved by the adopting of valve plug. However, very limited information is avallable in literature regarding the influence of valve plug on the internal and external features in globe control valves. Thus the effect of valve plug is studied by CFD and experiment in this paper. It is obtalned from external features that the pressure drop between upstream and downstream pressure-sampling position increases exponentially with flow rate. And for small valve opening, the increment of pressure drop decreases with the increase of cone angle (β). However, with the increase of valve opening, the effect of cone angle diminishes significantly. It is also found that the cone angle has little effect on flow coefficient (Cv) when the valve opening is larger than 70%. But for the cases less than 70%, Cv curve varies from an arc to a stralght line. The variation of valve performance is caused by the change of internal flow. The results of internal flow show that cone angle has negligible effect on flow properties for the cases of valve opening larger than 70%. However, when valve opening is smaller than 70%, the pressure drop of orifice decreases with the increase ofβ, making the reduction in value and scope of the high speed zone around the conical surface of valve plug, and then results in a decreasing intensity of adjacent downstream vortex. Meanwhile, it is concluded from the results that the increase of cone angle will be beneficial for the anti-cavitation and anti-erosion of globe control valve. This paper focuses on the internal and external features of globe control valve that caused by the variation of cone angle, arriving at some results beneficial for the design and usage of globe control valve.

  17. Integrated nozzle - flapper valve with piezoelectric actuator and isothermal chamber: a feedback linearization multi control device

    Energy Technology Data Exchange (ETDEWEB)

    Kamali, Mohammadreza; Jazayeri, Seyed Ali [K. N.Toosi University of Technology, Tehran (Iran, Islamic Republic of); Najafi, Farid [University of Guilan, Rasht (Iran, Islamic Republic of); Kawashima, Kenji [Tokyo Medical and Dental University, Tokyo (Japan); Kagawa, Toshiharu [Tokyo Institute of Technology, Tokyo (Japan)

    2016-05-15

    This paper introduces a new nozzle-flapper valve with isothermal chamber using piezoelectric actuator. It controls the pressure and flow rate simply, effectively and separately. The proposed valve uses isothermal chamber presenting practical isothermal condition due to its large heat transfer interfaces filled by metal wool. The valve uses stacked type piezoelectric actuator with unique advantages. By using this valve, a simple method has been fulfilled to control flow rate or pressure of ideal gases in a pneumatic actuators. Experimental results demonstrated applications of the proposed valve to control either pressure or flow rate in pneumatic circuits. This valve can be also used in the pilot stage valve to actuate the main stage of a much bigger pneumatic valve. Designated structure contains only one pressure sensor installed on the isothermal control chamber, capable of controlling both pressure and flow rate. The desired output mass flow rate of the valve is controlled by the pressure changes during positioning of piezoelectric actuator at proper position. The proposed valve can control steady and unsteady oscillatory flow rate and pressure effectively, using nonlinear control method such as feedback linearization approach. Its effectiveness is demonstrated and validated through simulation and experiments.

  18. Development of myoelectric control type speaking valve with low flow resistance

    Science.gov (United States)

    Ooe, Katsutoshi; Sakurai, Kohei; Mimaki, Shinya

    2015-12-01

    We aimed to develop welfare devices for patients with phonation disorder. One of these devices is the electrical controltype speaking valve system. The conventional speaking valves have one-way valve architecture, they open when the user breathes in, and they close when user breathes out and produce voices. This type is very simple and tough, but some users feel closeness in case of exhalation without phonation. This problem is caused by its mechanism what can not be controlled by user's will. Therefore, we proposed an electrical control-type speaking valve system to resolve this problem. This valve is controlled by neck myoelectric signal of sternohyoid muscle. From our previous report, it was clarified that this valve had better performance about easy-to-breath. Furthermore, we proposed the compact myoelectric control-type speaking valve system. The new-type speaking valve was enough small to attach the human body, and its opening area is larger than that of conventional one. Additionally, we described the improvement of flow channel shape by using of FEM analysis. According to the result of the analysis, it was clarified that the shape-improved speaking valve gets the low flow resistance channel in case of inspiration. In this report, we tried to make the flow resistance lower by the shape of current plates, in case of both inspiration and exhalation. From the result of FEM analysis, our speaking valve could get better flow channel than older one.

  19. Equilibrating Pressure with Auto-Control Valve in Water Distribution Networks

    Institute of Scientific and Technical Information of China (English)

    张宏伟; 闫晓强; 张丽

    2003-01-01

    This paper probes into the feasibility of equilibrating pressure of water distribution network through using auto-control valves in theory and in the economy. An optimal valve control model is designed to minimize the sum of squares of residual pressure in the network. Such an analog simulation has been performed on the year 2003 programming network of a certain littoral district in North China, through which this paper confirms that it is feasible to equilibrate pressure with auto-control valves in theory. The research work has brought about a discovery of applicable conditions of valves in economic feasibility, which avoids a great economic loss due to the wild use of auto-control valve. In addition, simulated annealing algorithm is applied to optimize valve settings and shown to identify global optimum or near-optimum.

  20. Hydraulic High Pressure Valve Controller Using the In-Situ Pressure Difference

    Science.gov (United States)

    Bao, Xiaoqi (Inventor); Sherrit, Stewart (Inventor); Badescu, Mircea (Inventor); Bar-Cohen, Yoseph (Inventor); Hall, Jeffery L. (Inventor)

    2016-01-01

    A hydraulic valve controller that uses an existing pressure differential as some or all of the power source for valve operation. In a high pressure environment, such as downhole in an oil or gas well, the pressure differential between the inside of a pipe and the outside of the pipe may be adequately large to drive a linear slide valve. The valve is operated hydraulically by a piston in a bore. When a higher pressure is applied to one end of the bore and a lower pressure to the other end, the piston moves in response to the pressure differential and drives a valve attached to it. If the pressure differential is too small to drive the piston at a sufficiently high speed, a pump is provided to generate a larger pressure differential to be applied. The apparatus is conveniently constructed using multiport valves, which can be rotary valves.

  1. Fuzzy Pattern Classification Based Detection of Faulty Electronic Fuel Control (EFC Valves Used in Diesel Engines

    Directory of Open Access Journals (Sweden)

    Umut Tugsal

    2014-05-01

    Full Text Available In this paper, we develop mathematical models of a rotary Electronic Fuel Control (EFC valve used in a Diesel engine based on dynamic performance test data and system identification methodology in order to detect the faulty EFC valves. The model takes into account the dynamics of the electrical and mechanical portions of the EFC valves. A recursive least squares (RLS type system identification methodology has been utilized to determine the transfer functions of the different types of EFC valves that were investigated in this study. Both in frequency domain and time domain methods have been utilized for this purpose. Based on the characteristic patterns exhibited by the EFC valves, a fuzzy logic based pattern classification method was utilized to evaluate the residuals and identify faulty EFC valves from good ones. The developed methodology has been shown to provide robust diagnostics for a wide range of EFC valves.

  2. The Nordic Aortic Valve Intervention (NOTION trial comparing transcatheter versus surgical valve implantation: study protocol for a randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Thyregod Hans Gustav

    2013-01-01

    Full Text Available Abstract Background Degenerative aortic valve (AV stenosis is the most prevalent heart valve disease in the western world. Surgical aortic valve replacement (SAVR has until recently been the standard of treatment for patients with severe AV stenosis. Whether transcatheter aortic valve implantation (TAVI can be offered with improved safety and similar effectiveness in a population including low-risk patients has yet to be examined in a randomised setting. Methods/Design This randomised clinical trial will evaluate the benefits and risks of TAVI using the transarterial CoreValve System (Medtronic Inc., Minneapolis, MN, USA (intervention group compared with SAVR (control group in patients with severe degenerative AV stenosis. Randomisation ratio is 1:1, enrolling a total of 280 patients aged 70 years or older without significant coronary artery disease and with a low, moderate, or high surgical risk profile. Trial outcomes include a primary composite outcome of myocardial infarction, stroke, or all-cause mortality within the first year after intervention (expected rates 5% for TAVI, 15% for SAVR. Exploratory safety outcomes include procedure complications, valve re-intervention, and cardiovascular death, as well as cardiac, cerebral, pulmonary, renal, and vascular complications. Exploratory efficacy outcomes include New York Heart Association functional status, quality of life, and valve prosthesis and cardiac performance. Enrolment began in December 2009, and 269 patients have been enrolled up to December 2012. Discussion The trial is designed to evaluate the performance of TAVI in comparison with SAVR. The trial results may influence the choice of treatment modality for patients with severe degenerative AV stenosis. Trial registration ClinicalTrials.gov: NCT01057173

  3. Modelling, Analysis, Control and Experimental Validation of Electromechanical Valve Actuators in Automotive Systems

    OpenAIRE

    Hoyos Velasco, Carlos Ildefonso

    2011-01-01

    This Thesis is concerned with the modelling, analysis and control of novel mechatronic valve actuators for automotive systems, specifically, the control of the mechanical valves to intake and exhaust gases in Internal Combustion Engines (ICE). Scientific studies have shown that significant benefits in terms of engine efficiency and emissions can be obtained through the adoption of variable valve actuation. Current engine technology are based on the use of a mechanical driven camshaft, which i...

  4. Quality control in homograft valve processing: when to screen for microbiological contamination?

    Science.gov (United States)

    Soo, Alan; Healy, David G; El-Bashier, Hatim; Shaw, Sandra; Wood, Alfred E

    2011-08-01

    rate, although significant, reflects rigorous quality control and the optimal balance between valve availability and patient safety.

  5. Technology Reinvestment Program/Advanced ``Zero Emission'' Control Valve (Phase II)

    Energy Technology Data Exchange (ETDEWEB)

    J. Napoleon

    1998-12-01

    The objectives of this effort are to determine, develop and demonstrate the feasibility of significantly reducing the cost and expanding the applications for a family of Advanced Zero Emissions Control Valves that meets the fugitive emissions requirements of the 1990 Amendments to the Clean Air Act. This program is a direct technology spin-off from the valve technology that is critical to the US Navy's Nuclear Powered Fleet. These zero emissions valves will allow the Hydrocarbon and Chemical Processing Industries, etc., to maintain their competitiveness and still meet environmental and safety requirements. Phase 2 is directed at refining the basic technologies developed during Phase 1 so that they can be more readily selected and utilized by the target market. In addition to various necessary certifications, the project will develop a full featured digital controller with ``smart valve'' growth capability, expanding valve sizes/applications and identifying valve materials to permit applications in severe operational environments.

  6. PWM Flow Rate Control of ER Valve and its Application to ER Actuator Control

    Science.gov (United States)

    Nakano, Masami; Minagawa, Shuji; Hagino, Katsuya

    The PWM (Pulse Width Modulation) control of ER valve consisting of two parallel electrodes has been investigated to continuously control the flow rate of an electrorheological (ER) suspension containing sulfonated polymer particles in silicone oil. PWM wave voltages are applied to the electrodes of the ER valve. It is possible to control continuously the flow rate by changing the duty ratio of the PWM wave from 1 to 0, where the duty ratio of 1 corresponds to the state to stop the flow. A miniature bellows actuator driven by a pair of PWM controlled ER valves has been developed, and the control characteristics of the actuator have been investigated. The duty ratios of both ER valves have been proposed to be changed alternately in proportion to the control voltage V to control the flow rate into and out of the bellows chamber, and also an overlap duty ratio Dov at V=0V has been introduced. The introduction of the overlap duty ratio Dov was found to be very important to smoothly control the actuator and to improve the control performance.

  7. Experimental System Identification and Black Box Modeling of Hydraulic Directional Control Valve

    Directory of Open Access Journals (Sweden)

    Sondre Sanden Tørdal

    2015-10-01

    Full Text Available Directional control valves play a large role in most hydraulic systems. When modeling the hydraulic systems, it is important that both the steady state and dynamic characteristics of the valves are modeled correctly to reproduce the dynamic characteristics of the entire system. In this paper, a proportional valve (Brevini HPV 41 is investigated to identify its dynamic and steady state characteristics. The steady state characteristics are identified by experimental flow curves. The dynamics are determined through frequency response analysis and identified using several transfer functions. The paper also presents a simulation model of the valve describing both steady state and dynamic characteristics. The simulation results are verified through several experiments.

  8. Identification of Stiction Nonlinearity for Pneumatic Control Valve using ANFIS Method

    Directory of Open Access Journals (Sweden)

    Srinivasan Arumugam

    2014-05-01

    Full Text Available Valve stiction is one of the prominent stand-alone reasons for oscillatory behavior in process industry. Stiction is a common problem in spring diaphragm type valves, which are widely used in the process industry. This behavior leads control valves to deliver accurate feed and thereby allowing wastage of utility. Recently, there have been many attempts to understand, define, model and detect stiction in control valves. Most of the available methods cannot simultaneously detect and quantify stiction. The paper presents an Adaptive Neuro-Fuzzy methodology for identification of stiction. For a vertical two tank level process with Kano’s model of stiction is considered to obtain necessary required data to formulate objective function. The proposed methods for detecting and quantifying stiction are applied on the flow control valve using MATLAB/Simulink platform.

  9. ADAPTIVE CONTROLLER AND ITS APPLICATION IN FORCE SYSTEM OF ASYMMETRIC CYLINDER CONTROLLED BY SYMMETRIC VALVE

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Partial pressure, system vibration and asymmetric system dynamic performance exit in asymmetric cylinder controller by symmetric valve hydraulic system. To solve this problem in the force control system, model reference adaptive controller is designed using equilibrium point stability theory and output error equation polynomial. The reference model is selected in such a way that it meets the system dynamic performance. Hardware configuration of asymmetric cylinder controlled by asymmetric valve hydraulic system is replaced by intelligent control algorithm, thus the cost is lowered and easy to application. Simulation results demonstrate that the proposed adaptive control sheme has good adaptive ability and well solves asymmetric dynamic performance problem. The designed adaptive controller is fairly robust to load disturbance and system parameter variation.

  10. Design of pilot-assisted load control valve with load velocity control ability and fast opening feature

    Directory of Open Access Journals (Sweden)

    Haibo Xie

    2015-11-01

    Full Text Available This article presents a design of pilot-assisted load control valve with load velocity control ability and fast opening feature based on static and dynamic modeling. Traditional load control valves do not have the load velocity control ability and its opening feature is very poor because the high spring stiffness comes along with the pressure–spring balance–based principle. Some improvement has been done by employing a two-stage pressure–pressure balance principle to make a load control valve to achieve load velocity control ability while the opening feature was not improved much. In this design, another pressure–pressure balance principle is proposed to make the load control valve achieve load velocity control ability and fast opening closing feature at the same time. Static modeling method based on force balance and Bernoulli orifice pressure-flow equation is used to design the load velocity control ability of the valve. Dynamic modeling method based on Newton’s second law and fluid continuity equation is used to optimize the parameters to give the proposed load control valve a fast opening feature. An actual load control valve was developed according to the above methods and the test results show both good load velocity control ability and fast opening feature of the design, which validates the potentiality of the proposed design in many applications.

  11. Pressure- and flow-control valves in power plant piping; Armaturen fuer Druck- und Durchflussregelung in Kraftwerksleitungen

    Energy Technology Data Exchange (ETDEWEB)

    Daume, Britta; Carstensen, Bjoern [Daume Regelarmaturen GmbH, Isernhagen (Germany)

    2010-06-15

    Control valves are used in the most diverse range of industries. This article focuses on the design and construction of valves for regulation of pressure and flow in the piping of power generation plants. (orig.)

  12. Analysis of Liquid Zone Control Valve Oscillation Problem in CANDU Reactors

    OpenAIRE

    Elnara Nasimi; Hossam A. Gabbar

    2013-01-01

    This paper looks at the existing challenges with steady-state Liquid Zone control at some CANDU (CANada Deuterium Uranium) stations, where—contrary to expectations for equilibrium flow—Liquid Zone Control Valve oscillations have proven to be a chronic, unanticipated challenge. Currently, the exact causes of this behaviour are not fully understood, although it is confirmed that the Control Valve oscillations are not due to automatic power adjustment requests or zone level changes due to proces...

  13. Detecting Solenoid Valve Deterioration in In-Use Electronic Diesel Fuel Injection Control Systems

    OpenAIRE

    Chyuan-Yow Tseng; Hsun-Heng Tsai

    2010-01-01

    The diesel engine is the main power source for most agricultural vehicles. The control of diesel engine emissions is an important global issue. Fuel injection control systems directly affect fuel efficiency and emissions of diesel engines. Deterioration faults, such as rack deformation, solenoid valve failure, and rack-travel sensor malfunction, are possibly in the fuel injection module of electronic diesel control (EDC) systems. Among these faults, solenoid valve failure is most likely to oc...

  14. Enhanced rhamnolipids production via efficient foam-control using stop valve as a foam breaker.

    Science.gov (United States)

    Long, Xuwei; Shen, Chong; He, Ni; Zhang, Guoliang; Meng, Qin

    2017-01-01

    In this study, a stop valve was used as a foam breaker for dealing with the massive overflowing foam in rhamnolipid fermentation. As found, a stop valve at its tiny opening could break over 90% of the extremely stable rhamnolipid foam into enriched liquid when foam flows through the sharp gap in valve. The efficient foam-control by the stop valve considerably improved the rhamnolipid fermentation and significantly enhanced the rhamnolipid productivity by 83% compared to the regular fermentation. This efficient foam breaking was mainly achieved by a high shear rate in combination with fast separation of air from the collapsed foam. Altogether, the stop valve possessed a great activity in breaking rhamnolipid foam, and the involving mechanism holds the potential for developing efficient foam breakers for industrial rhamnolipid fermentation.

  15. An experimental study on flowrate and stability for 600MW supercritical steam-turbine control valve

    Institute of Scientific and Technical Information of China (English)

    相晓伟; 毛靖儒; 孙弼

    2007-01-01

    An experimental study on flowrate and stability of a type of control valve of 600MW supercritical steam-turbine was presented by measuring instruments of static, dynamic pressure and vibration in self-designed test rig. The investigation shows that flow coefficient is 30% up more than that of the control valve of GX-1 type used widely in domestic power plants now, as small-medium lifts. If the relative lift (h/D) is less than 20%, the valve can always work steadily in all the pressure ratios. When the h/D i...

  16. Study on the design of industrial control valves with manual drive

    Directory of Open Access Journals (Sweden)

    Pascariu Andrei

    2017-01-01

    Full Text Available The paper presents the main components and the operating mode of the manually operated control valves used in natural gas transport and distribution installations. Main parameters are specified: inlet-outlet pressure (P, temperature(T, flow rate (Q, which are taken into considerations from the design phase and beyond. Noise is another parameter, in close liaison with the pressure and flow. As their value increases with both the inlet noise levels downstream of the valve is greater. By optimizing internal components, especially cages, noise can be limited below the maximum allowed by regulations. Also, there are presented control valve constructive types so that the optimal variant can be chose.

  17. Modelling of flow in the unloading slot of the control valve

    Science.gov (United States)

    Mrózek, Lukáš; Tajč, Ladislav

    2017-09-01

    The flow in the unloading system of the control valve is modelled. Values of the flow coefficient for various slot widths and openings are evaluated. The changes of pressure in the spaces of the valve are recorded when the performance of the turbine is regulated and its impacts on the level of the stabilizing power at the given setting of the cone lift are evaluated. The results from experiments on the air model of the system are compared with the pressures measured on the model of the valve. The operational characteristics of the experimental steam turbine is considered.

  18. Controller Development for a Separate Meter-In Separate Meter-Out Fluid Power Valve for Mobile Applications

    DEFF Research Database (Denmark)

    Nielsen, Brian

    by a single pump the fluid is distributed through valves. A valve works by controlling a fluid stream through the valve by varying the opening of an orifice. The disadvantage by this is that when controlling the fluid flow rate a pressure drop is created across the orifice. This results in a throttle loss......, which is commonly used in many types of mobile applications, is a 4-way proportional valve. In this type of valve two fluid streams are controlled: One fluid stream from a pump to a fluid consumer and one fluid stream from the fluid consumer to a fluid reservoir. In a 4-way proportional valve...... it is necessary to use a separate control of the two fluid streams to minimise the throttling losses. The purpose of the research documented in this dissertation is to investigate how a 4-way proportional valve may be build to fulfil the increasing demands with regard to energy efficiency and functionality...

  19. Nonlinear variable structure excitation and steam valving controllers for power system stability

    Institute of Scientific and Technical Information of China (English)

    Ben WANG; Zongyuan MAO

    2009-01-01

    A set of novel nonlinear variable structure excitation and steam-valving controllers are proposed in this paper.On the basis of the classical dynamic equations of a generator,excitation control and steam valving control are si-multaneously considered.Design of these controllers combines the differential geometry theory with the variable structure controlling theory.The mathematical model in the form of "an affine nonlinear system" is set up for the control design of a large-scale power plant.The dynamic performance of the nonlinear variable structure controllers proposed for a single ma-chine connected to an infinite bus power system is simulated.Simulation results show that the nonlinear variable structure excitation and steam-valving controllers give satisfactory dynamic performance and good robustness.

  20. Some aspects of numerical simulation of control valves for steam turbines

    Directory of Open Access Journals (Sweden)

    Matas Richard

    2012-04-01

    Full Text Available The contribution deals with the numerical simulation of air and steam flow through the model of control valve for steam turbines. Numerical simulations were compared with experimental measurements for the award of the same boundary conditions. Valve characteristics have been computed for individual travel heights and pressure ratios of two variants of seat inflow angle (90° and 60°. Some other aspects are discussed in the article - comparison of the axysymmetric and 3D modelling, influence of the computational domain size, comparison of characteristics for two flow media, experimental model of the valve etc. The mentioned results are important for engineering simulations and also for design of the control valves for steam turbines of the large output.

  1. An experimental study on flowrate and stability for 600MW supercritical steam-turbine control valve

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    An experimental study on flowrate and stability of a type of control valve of 600MW supercritical steam-turbine was presented by measuring instruments of static, dynamic pressure and vibration in self-designed test rig. The investigation shows that flow coefficient is 30% up more than that of the control valve of GX-1 type used widely in domestic power plants now, as small-medium lifts. If the relative lift (h/D) is less than 20%, the valve can always work steadily in all the pressure ratios. When the h/D is between 20% to 24%, big vibration of valve stem occurs if the pressure ratio is between 0.7 to 0.8. When h/D is more than 25%, relatively great vibration happens in a wide range of pressure ratios of 0.4 to 0.85.

  2. Application of High-speed Solenoid Valve to the Semi-active Control of Landing Gear

    Institute of Scientific and Technical Information of China (English)

    Liu Hui; Gu Hongbin; Chen Dawei

    2008-01-01

    To select or develop an appropriate actuator is one of the key and difficult issues in the study of semi-active controlled landing gear.Performance of the actuator may directly affect the effectiveness of semi-active control.In this article,parallel high-speed solenoid valves are chosen to be the actuators for the semi-active controlled landing gear and being studied.A nonlinear high-speed solenoid valve model is developed with the consideration of magnctic saturation characteristics and verified by test.According to the design rule of keeping the peak load as small as possible while absorbing the specified shock energy,a fuzzy PD control rule is designed.By the rule,controller parameters can be self-regulated.The simulation results indicate that the semi-active control based on high-speed solenoid valve can effectively improve the control performance and reduce impact load during landing.

  3. Low cost valves motorization using micro controller; Motorizacion de valvulas de bajo coste mediante microcontrolador

    Energy Technology Data Exchange (ETDEWEB)

    Menendez, A.; Leal, M. A.; Dominguez Ademe, G.; Yaglian, E.

    2004-07-01

    This article describes a new solution for valves motorization with the objective to obtain a minimum cost and a minimum size. With it, it is proposed to facilitate the complex applications of automation in the hydraulic sector, with multiple volume and pressure controls, like the one made on Integrated Digital Control of Desalting Water Plants. The design presented here consists basically of an original mechanical connection that allows to use standard market valves and moto-gearboxes and a simplified electronic controller based on a micro controller with an elaborated software that allows to control the mother either in ON/Off (open/close) applications or in incremental applications of Regulation. (Author)

  4. MODELING, VALIDATION AND OPTIMAL DESIGN OF THE CLAMPING FORCE CONTROL VALVE USED IN CONTINUOUSLY VARIABLE TRANSMISSION

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yunshan; LIU Jin'gang; CAI Yuanchun; ZOU Naiwei

    2008-01-01

    Associated dynamic performance of the clamping force control valve used in continuously variable transmission (CVT) is optimized. Firstly, the structure and working principle of the valve are analyzed, and then a dynamic model is set up by means of mechanism analysis. For the purpose of checking the validity of the modeling method, a prototype workpiece of the valve is manufactured for comparison test, and its simulation result follows the experimental result quite well. An associated performance index is founded considering the response time, overshoot and saving energy, and five structural parameters are selected to adjust for deriving the optimal associated performance index. The optimization problem is solved by the genetic algorithm (GA) with necessary constraints. Finally, the properties of the optimized valve are compared with those of the prototype workpiece, and the results prove that the dynamic performance indexes of the optimized valve are much better than those of the prototype workpiece.Key words: Dynamic modeling Optimal design Genetic algorithm Clamping force control valve Continuously variable transmission (CVT)

  5. Synthesis of sequential control algorithms for pneumatic drives controlled by monostable valves

    Directory of Open Access Journals (Sweden)

    Ł. Dworzak

    2009-07-01

    Full Text Available Application of the Grafpol method [1] for synthesising sequential control algorithms for pneumatic drives controlled by monostable valves is presented. The developed principles simplify the MTS method of programming production processes in the scope of the memory realisation [2]. Thanks to this, time for synthesising the schematic equation can be significantly reduced in comparison to the network transformation method [3]. The designed schematic equation makes a ground for writing an application program of a PLC using any language defined in IEC 61131-3.

  6. Detecting Solenoid Valve Deterioration in In-Use Electronic Diesel Fuel Injection Control Systems

    Directory of Open Access Journals (Sweden)

    Chyuan-Yow Tseng

    2010-07-01

    Full Text Available The diesel engine is the main power source for most agricultural vehicles. The control of diesel engine emissions is an important global issue. Fuel injection control systems directly affect fuel efficiency and emissions of diesel engines. Deterioration faults, such as rack deformation, solenoid valve failure, and rack-travel sensor malfunction, are possibly in the fuel injection module of electronic diesel control (EDC systems. Among these faults, solenoid valve failure is most likely to occur for in-use diesel engines. According to the previous studies, this failure is a result of the wear of the plunger and sleeve, based on a long period of usage, lubricant degradation, or engine overheating. Due to the difficulty in identifying solenoid valve deterioration, this study focuses on developing a sensor identification algorithm that can clearly classify the usability of the solenoid valve, without disassembling the fuel pump of an EDC system for in-use agricultural vehicles. A diagnostic algorithm is proposed, including a feedback controller, a parameter identifier, a linear variable differential transformer (LVDT sensor, and a neural network classifier. Experimental results show that the proposed algorithm can accurately identify the usability of solenoid valves.

  7. Detecting solenoid valve deterioration in in-use electronic diesel fuel injection control systems.

    Science.gov (United States)

    Tsai, Hsun-Heng; Tseng, Chyuan-Yow

    2010-01-01

    The diesel engine is the main power source for most agricultural vehicles. The control of diesel engine emissions is an important global issue. Fuel injection control systems directly affect fuel efficiency and emissions of diesel engines. Deterioration faults, such as rack deformation, solenoid valve failure, and rack-travel sensor malfunction, are possibly in the fuel injection module of electronic diesel control (EDC) systems. Among these faults, solenoid valve failure is most likely to occur for in-use diesel engines. According to the previous studies, this failure is a result of the wear of the plunger and sleeve, based on a long period of usage, lubricant degradation, or engine overheating. Due to the difficulty in identifying solenoid valve deterioration, this study focuses on developing a sensor identification algorithm that can clearly classify the usability of the solenoid valve, without disassembling the fuel pump of an EDC system for in-use agricultural vehicles. A diagnostic algorithm is proposed, including a feedback controller, a parameter identifier, a linear variable differential transformer (LVDT) sensor, and a neural network classifier. Experimental results show that the proposed algorithm can accurately identify the usability of solenoid valves.

  8. Design of nonlinear adaptive steam valve controllers for a turbo-generator system

    Energy Technology Data Exchange (ETDEWEB)

    Bekiaris-Liberis, N.K.; Paraskevopoulos, P.N. [National Technical Univ. of Athens Zographou, Athens (Greece); Boglou, A.K. [Technology Education Inst. of Kavala Agios Loukas, Kavala (Greece); Arvanitis, K.G.; Pasgianos, G.D. [Agricultural Univ. of Athens, Athens (Greece)

    2008-07-01

    This paper reported on a study that investigated the control of power systems consisting of interconnected networks of transmission lines linking generators and loads. Improving both small and large perturbation stability and dynamic performance is important because power systems have become less stable in the past 15 years due to the use of controllers that have been designed on the basis of linearized synchronous generators and turbine models. The high nonlinear nature of power system models and the resulting disturbances render conventional linear controller design techniques obsolete for use in power systems control. Power system engineers are becoming aware of the role of turbine steam valves in improving the dynamic stability of power systems and damping low frequency oscillations. Advanced nonlinear control strategies are needed since the conventional steam valve control theory cannot guarantee transient stability in cases where operational conditions and parameters vary considerably. A design approach to a nonlinear adaptive control system with unknown parameters was developed and applied to the turbine main steam valve control of a power system. A fourth order machine model was used along with an adaptive backstepping method to construct the Lyapunov function in order to obtain a nonlinear adaptive controller to solve the turbine fast valving nonlinear control problem. The newly designed nonlinear adaptive controller can make the resulting adaptive system asymptotically stable. The proposed controller is accompanied by a dynamic estimator of parameters and includes nonlinear damping terms, which guarantee input-output stability even without the use of the adaptive law. Simulation results showed that the proposed nonlinear adaptive controller performs better than other turbine main steam valve control techniques. It can face large parametric uncertainty and results in a closed-loop system that is able to face large and smaller disturbances, providing a

  9. High precise control method for a new type of piezoelectric electro-hydraulic servo valve

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new type of piezoelectric electro-hydraulic servo valve system was proposed. And then multilayer piezoelectric actuator based on new piezoelectric ceramic material was used as the electricity-machine converter of the proposed piezoelectric electro-hydraulic servo valve. The proposed piezoelectric electro-hydraulic servo valve has ascendant performance compared with conventional ones. But the system is of high nonlinearity and uncertainty, it cannot achieve favorable control performance by conventional control method. To develop an efficient way to control piezoelectric electro-hydraulic servo valve system, a high-precise fuzzy control method with hysteresis nonlinear model in feedforward loop was proposed. The control method is separated into two parts: a feedforward loop with Preisach hysteresis nonlinear model and a feedback loop with high-precise fuzzy control. Experimental results show that the hysteresis loop and the maximum output hysteresis by the PID control method are 4.22%and 2.11 μm, respectively; the hysteresis loop and the maximum output hysteresis by the proposed control method respectively are 0.74% and 0.37 μm, respectively; the maximum tracking error by the PID control method for sine wave reference signal is about 5.02%, the maximum tracking error by the proposed control method for sine wave reference signal is about 0.85%.

  10. A Generic Model Based Tracking Controller for Hydraulic Valve-Cylinder Drives

    DEFF Research Database (Denmark)

    Hansen, Anders Hedegaard; Schmidt, Lasse; Pedersen, Henrik Clemmensen

    2016-01-01

    , and are therefore constrained to utilize only measurements of the piston position, the valve spool position, the transmission line pressures and the supply pressure, as feedbacks. The control structures are generally targeting a high bandwidth of the controlled cylinder drive and accurate tracking ability...

  11. Diaphragm control valves - Solutions for different applications; Membran-Regelventile - Loesungen fuer verschiedene Anwendungsfaelle

    Energy Technology Data Exchange (ETDEWEB)

    Dylla, J. [AVK Mittelmann Armaturen GmbH, Wuelfrath (Germany)

    2003-09-01

    This article examines conveyed-fluid-actuated diaphragm-type control values, using the example of a specific type. After an introduction to the basic nomenclature of the valves, their structure and manner of action is explained and their advantages outlined. A number of selected examples are used to illustrate the potential applications for diaphragm-type control valves. (orig.) [German] Der Beitrag befasst sich mit eigenmediumgesteuerten Membran-Regelventilen, beschrieben am Beispiel einer bestimmten Bauart. Nach der Erlaeuterung von Grundbegriffen wird der Aufbau und die Wirkungsweise dieser Ventile erlaeutert und die Vorteile aufgezeigt. Anhand von ausgewaehlten Beispielen werden Einsatzmoeglichkeiten von Membran-Regelventilen vorgestellt. (orig.)

  12. Acoustic-Modal Testing of the Ares I Launch Abort System Attitude Control Motor Valve

    Science.gov (United States)

    Davis, R. Benjamin; Fischbach, Sean R.

    2010-01-01

    The Attitude Control Motor (ACM) is being developed for use in the Launch Abort System (LAS) of NASA's Ares I launch vehicle. The ACM consists of a small solid rocket motor and eight actuated pintle valves that directionally allocate.thrust_- 1t.has-been- predicted-that significant unsteady. pressure.fluctuations.will.exist. inside the-valves during operation. The dominant frequencies of these oscillations correspond to the lowest several acoustic natural frequencies of the individual valves. An acoustic finite element model of the fluid volume inside the valve has been critical to the prediction of these frequencies and their associated mode shapes. This work describes an effort to experimentally validate the acoustic finite model of the valve with an acoustic modal test. The modal test involved instrumenting a flight-like valve with six microphones and then exciting the enclosed air with a loudspeaker. The loudspeaker was configured to deliver broadband noise at relatively high sound pressure levels. The aquired microphone signals were post-processed and compared to results generated from the acoustic finite element model. Initial comparisons between the test data and the model results revealed that additional model refinement was necessary. Specifically, the model was updated to implement a complex impedance boundary condition at the entrance to the valve supply tube. This boundary condition models the frequency-dependent impedance that an acoustic wave will encounter as it reaches the end of the supply tube. Upon invoking this boundary condition, significantly improved agreement between the test data and the model was realized.

  13. Performance Evaluation of a High Bandwidth Liquid Fuel Modulation Valve for Active Combustion Control

    Science.gov (United States)

    Saus, Joseph R.; DeLaat, John C.; Chang, Clarence T.; Vrnak, Daniel R.

    2012-01-01

    At the NASA Glenn Research Center, a characterization rig was designed and constructed for the purpose of evaluating high bandwidth liquid fuel modulation devices to determine their suitability for active combustion control research. Incorporated into the rig s design are features that approximate conditions similar to those that would be encountered by a candidate device if it were installed on an actual combustion research rig. The characterized dynamic performance measures obtained through testing in the rig are planned to be accurate indicators of expected performance in an actual combustion testing environment. To evaluate how well the characterization rig predicts fuel modulator dynamic performance, characterization rig data was compared with performance data for a fuel modulator candidate when the candidate was in operation during combustion testing. Specifically, the nominal and off-nominal performance data for a magnetostrictive-actuated proportional fuel modulation valve is described. Valve performance data were collected with the characterization rig configured to emulate two different combustion rig fuel feed systems. Fuel mass flows and pressures, fuel feed line lengths, and fuel injector orifice size was approximated in the characterization rig. Valve performance data were also collected with the valve modulating the fuel into the two combustor rigs. Comparison of the predicted and actual valve performance data show that when the valve is operated near its design condition the characterization rig can appropriately predict the installed performance of the valve. Improvements to the characterization rig and accompanying modeling activities are underway to more accurately predict performance, especially for the devices under development to modulate fuel into the much smaller fuel injectors anticipated in future lean-burning low-emissions aircraft engine combustors.

  14. Acoustic-Modal Testing of the Ares I Launch Abort System Attitude Control Motor Valve

    Science.gov (United States)

    Davis, R. Benjamin; Fischbach, Sean R.

    2010-01-01

    The Attitude Control Motor (ACM) is being developed for use in the Launch Abort System (LAS) of NASA's Ares I launch vehicle. The ACM consists of a small solid rocket motor and eight actuated pintle valves that directionally allocate.thrust_- 1t.has-been- predicted-that significant unsteady. pressure.fluctuations.will.exist. inside the-valves during operation. The dominant frequencies of these oscillations correspond to the lowest several acoustic natural frequencies of the individual valves. An acoustic finite element model of the fluid volume inside the valve has been critical to the prediction of these frequencies and their associated mode shapes. This work describes an effort to experimentally validate the acoustic finite model of the valve with an acoustic modal test. The modal test involved instrumenting a flight-like valve with six microphones and then exciting the enclosed air with a loudspeaker. The loudspeaker was configured to deliver broadband noise at relatively high sound pressure levels. The aquired microphone signals were post-processed and compared to results generated from the acoustic finite element model. Initial comparisons between the test data and the model results revealed that additional model refinement was necessary. Specifically, the model was updated to implement a complex impedance boundary condition at the entrance to the valve supply tube. This boundary condition models the frequency-dependent impedance that an acoustic wave will encounter as it reaches the end of the supply tube. Upon invoking this boundary condition, significantly improved agreement between the test data and the model was realized.

  15. Nonlinear Dynamic Model-Based Adaptive Control of a Solenoid-Valve System

    Directory of Open Access Journals (Sweden)

    DongBin Lee

    2012-01-01

    Full Text Available In this paper, a nonlinear model-based adaptive control approach is proposed for a solenoid-valve system. The challenge is that solenoids and butterfly valves have uncertainties in multiple parameters in the nonlinear model; various kinds of physical appearance such as size and stroke, dynamic parameters including inertia, damping, and torque coefficients, and operational parameters especially, pipe diameters and flow velocities. These uncertainties are making the system not only difficult to adjust to the environment, but also further complicated to develop the appropriate control approach for meeting the system objectives. The main contribution of this research is the application of adaptive control theory and Lyapunov-type stability approach to design a controller for a dynamic model of the solenoid-valve system in the presence of those uncertainties. The control objectives such as set-point regulation, parameter compensation, and stability are supposed to be simultaneously accomplished. The error signals are first formulated based on the nonlinear dynamic models and then the control input is developed using the Lyapunov stability-type analysis to obtain the error bounded while overcoming the uncertainties. The parameter groups are updated by adaptation laws using a projection algorithm. Numerical simulation results are shown to demonstrate good performance of the proposed nonlinear model-based adaptive approach and to compare the performance of the same solenoid-valve system with a non-adaptive method as well.

  16. Control performances of a piezoactuator direct drive valve system at high temperatures with thermal insulation

    Science.gov (United States)

    Han, Yung-Min; Han, Chulhee; Kim, Wan Ho; Seong, Ho Yong; Choi, Seung-Bok

    2016-09-01

    This technical note presents control performances of a piezoactuator direct drive valve (PDDV) operated at high temperature environment. After briefly discussing operating principle and mechanical dimensions of the proposed PDDV, an appropriate size of the PDDV is manufactured. As a first step, the temperature effect on the valve performance is experimentally investigated by measuring the spool displacement at various temperatures. Subsequently, the PDDV is thermally insulated using aerogel and installed in a large-size heat chamber in which the pneumatic-hydraulic cylinders and sensors are equipped. A proportional-integral-derivative feedback controller is then designed and implemented to control the spool displacement of the valve system. In this work, the spool displacement is chosen as a control variable since it is directly related to the flow rate of the valve system. Three different sinusoidal displacements with different frequencies of 1, 10 and 50 Hz are used as reference spool displacement and tracking controls are undertaken up to 150 °C. It is shown that the proposed PDDV with the thermal insulation can provide favorable control responses without significant tracking errors at high temperatures.

  17. Parallel Control of Velocity Control and Energy-Saving Control for a Hydraulic Valve-Controlled Cylinder System Using Self-Organizing Fuzzy Sliding Mode Control

    Science.gov (United States)

    Chiang, Mao-Hsiung; Chien, Yu-Wei

    Conventional hydraulic valve-controlled systems that incorporate positive displacement pumps and relief valves have a problem of low energy efficiency. The objective of the research is to implement parallel control of energy-saving control in an electro-hydraulic load-sensing system and velocity control in a hydraulic valve-controlled cylinder system to achieve both high velocity control accuracy and low input power simultaneously. The overall control system is a two-input two-output system. For that, the control strategy of self-organizing fuzzy sliding mode control (SOFSMC) is developed in this study to reduce the fuzzy rule number and to self-organize on-line the fuzzy rules. To compare the energy-saving performance, the velocity control is implemented under three different energy-saving control systems, such as load-sensing control system, constant supply pressure control system and conventional hydraulic system. The parallel control of the velocity control and energy-saving control by the SOFSMC is implemented experimentally.

  18. Scissor thrust valve actuator

    Science.gov (United States)

    DeWall, Kevin G.; Watkins, John C; Nitzel, Michael E.

    2006-08-29

    Apparatus for actuating a valve includes a support frame and at least one valve driving linkage arm, one end of which is rotatably connected to a valve stem of the valve and the other end of which is rotatably connected to a screw block. A motor connected to the frame is operatively connected to a motor driven shaft which is in threaded screw driving relationship with the screw block. The motor rotates the motor driven shaft which drives translational movement of the screw block which drives rotatable movement of the valve driving linkage arm which drives translational movement of the valve stem. The valve actuator may further include a sensory control element disposed in operative relationship with the valve stem, the sensory control element being adapted to provide control over the position of the valve stem by at least sensing the travel and/or position of the valve stem.

  19. Adaptive H-infinity control of synchronous generators with steam valve via Hamiltonian function method

    Institute of Scientific and Technical Information of China (English)

    Shujuan LI; Yuzhen WANG

    2006-01-01

    Based on Hamiltonian formulation, this paper proposes a design approach to nonlinear feedback excitation control of synchronous generators with steam valve control, disturbances and unknown parameters. It is shown that the dynamics of the synchronous generators can be expressed as a dissipative Hamiltonian system, based on which an adaptive H-infinity controller is then designed for the systems by using the structure properties of dissipative Hamiltonian systems.Simulations show that the controller obtained in this paper is very effective.

  20. Analysis of Dither in PWM Control on Electro-hydraulic Proportional Valve

    Directory of Open Access Journals (Sweden)

    Guoping LIU

    2013-11-01

    Full Text Available Plus with modulation (PWM is widely used in proporational control systems for it is efficient, flexible and anti-interference. Due to the friction and hysteresis of electromagnet, hysteresis exists when hydraulic valve in steady-state, and hysteresis influences the dynamic characteristics of the valve seriously,the hysteresis can be improved by superimposing dithers with certain frequency and amplitude to the valve coil. Aiming at the character of anti-unloading power driver circuit ,this paper analyzed the parasitic dither which exists in ±24V PWM control,besides,the experiment shows that in a high frequency PWM, dither with independent frequency and amplitude can be generated by changing the frequency of the PWM, in this way, the dithers  and average current of coil  can be adjusted separately by changing PWM frequency and PWM duty cycle.  

  1. Butterfly valve with metal seals controls flow of hydrogen from cryogenic through high temperatures

    Science.gov (United States)

    Johnson, L. D.

    1967-01-01

    Butterfly valve with metal seals operates over a temperature range of minus 423 degrees to plus 440 degrees F with hydrogen as a medium and in a radiation environment. Media flow is controlled by an internal butterfly disk which is rotated by an actuation shaft.

  2. Pneumatic shutoff and time-delay valve operates at controlled rate

    Science.gov (United States)

    Horning, J. L.; Tomlinson, L. E.

    1966-01-01

    Shutoff and time delay valve, which incorporates a metering spool that moves at constant velocity under pneumatic pressure and spring compression, increases fluid-flow area at a uniform rate. Diaphragm areas, control cavity volume, and bleed-orifice size may be varied to give any desired combination of time delay and spool travel time.

  3. A new control valve with a push rod for intermediate-pressure cylinders of steam turbines

    Science.gov (United States)

    Zaryankin, A. E.; Arianov, S. V.; Paramonov, A. N.; Gotovtsev, A. M.; Storozhuk, S. K.

    2007-11-01

    We describe a new design of a control valve for intermediate-pressure cylinders with a perforated cup and a push rod that ensures smaller loss under rated operating conditions and features better reliability. Model tests were carried out to check the main design solutions.

  4. An Analytic Approach to Cascade Control Design for Hydraulic Valve-Cylinder Drives

    DEFF Research Database (Denmark)

    Schmidt, Lasse; Hansen, Anders Hedegaard; Andersen, Torben O.

    2016-01-01

    control and possibly linear active damping functionalities. However difficulties often arise due to the inherent and strong nonlinear nature of hydraulic drives, with the more dominant being nonlinear valve flow- and oil stiffness characteristics, and furthermore the volume expansion/retraction when...

  5. Expert system for fault diagnosis in process control valves using fuzzy-logic

    Energy Technology Data Exchange (ETDEWEB)

    Carneiro, Alvaro L.G., E-mail: carneiro@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Porto Junior, Almir C.S., E-mail: almir@ctmsp.mar.mil.br [Centro Tecnologico da Marinha em Sao Paulo (CIANA/CTMSP), Ipero, SP (Brazil). Centro de Instrucao e Adestramento Nuclear de ARAMAR

    2013-07-01

    The models of asset maintenance of a process plant basically are classified in corrective maintenance, preventive, predictive and proactive (online). The corrective maintenance is the elementary and most obvious way of the maintenance models. The preventive maintenance consists in a fault prevention work, based on statistical studies that can lead to low efficiency or even an unexpected shutdown of the plant. Predictive maintenance aims to prevent equipment or systems failures through monitoring and tracking of parameters, allowing continuous operation as long as possible. The proactive maintenance usually includes predictive maintenance, emphasizing the root cause analysis of the failure. The maintenance predictive/proactive planning frequently uses software that integrates data from different systems, which facilitates a quick and effective decision- making. In nuclear plants this model has an important role regarding the reliability of equipment and systems. The main focus of this work is to study the development of a model of non-intrusive monitoring and diagnosis applied to process control valves using artificial intelligence by fuzzy logic technique, contributing in the development of predictive methodologies identifying faults in incipient state. The control valve analyzed belongs to a steam plant which simulates the secondary circuit of a PWR nuclear reactor - Pressurized Water Reactor. This study makes use of MATLAB language through the fuzzy logic toolbox which uses the method of inference Mamdani, acting by fuzzy conjunction, through Triangular Norms (t-norm) and Triangular Conorms (t-conorm). As input variables are used air pressure and displacement of the valve stem. Input data coming into the fuzzy system by graph of the automation system Delta V ® available in the plant, which receives a signal of electric current from an 'intelligent' positioned installed on the valve. The output variable is the 'status' of the valve. Through a

  6. Robust ‚H-2 static output feedback to control an automotive throttle valve

    OpenAIRE

    Vargas A.N.; Acho L.; Pujol G.; Oliveira R.C.L.F.; Do Val J.B.R.; Peres P.L.D.

    2014-01-01

    The paper presents a control strategy for an automotive electronic throttle body, a device largely used into vehicles to increase the efficiency of the combustion engines. The synthesis of the proposed controller is based on a linear matrix inequality (LMI) formulation, which allows us to deal with uncertainties on the measurements of the position of the throttle valve. The LMI approach generates a suboptimal solution for the robust ‚Ñã2 static output feedback control problem, and the corresp...

  7. Feasibility and testing of lighweight, energy efficient, additive manufactured pneumatic control valve

    Energy Technology Data Exchange (ETDEWEB)

    Love, Lonnie J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Mell, Ellen [Aerovalve, LLC, St. Louis, Mo (United States)

    2015-02-01

    AeroValve s innovative pneumatic valve technology recycles compressed air through the valve body with each cycle of the valve, and was reported to reduce compressed air requirements by an average of 25% 30%.This technology collaboration project between ORNL and Aerovalve confirms the energy efficiency of valve performance. Measuring air consumption per work completed, the AeroValve was as much as 85% better than the commercial Festo valve.

  8. Control valves and cascades for the first stages of turbines with ultrasupercritical steam parameters

    Science.gov (United States)

    Zaryankin, A. E.; Rogalev, N. D.; Rogalev, A. N.; Garanin, I. V.; Osipov, S. K.; Grigoriev, E. Yu.

    2016-06-01

    This paper considers the problems that will unavoidably be encountered in the creation of new-generation turbines operated at ultrasupercritical initial steam parameters, namely, the development of new control and shutoff valves, the reduction of end energy losses in blade cascades and steam leaks in high-pressure cylinders (HPCs), the elimination of effect produced by regenerative steam bleedoffs on the afterextraction stage, the cooling of a blade cascade, etc. Some possible solutions are given for the two first of the listed problems. The conclusion about the need for the transition to new-generation control valves in the development of new advanced steam turbines with ultrasupercritical initial steam parameters has been made. From the viewpoint of their design, the considered new-generation valves differ from the known contemporary constructions by a shaped axially symmetric confusor channel and perforated zones on the streamlined spool surface and the inlet diffuser saddle part. The analysis of the vibration behavior of new-generation valves has demonstrated a decrease in the dynamic loads acting on their stems. To reduce the end energy losses in nozzle or blade cascades with small aspect ratios, it is proposed to use finned shrouds in the interblade channels. The cross section of fins has a triangular profile, and their height must be comparable with the thickness of the boundary layer in the outlet cross section of a cascade and, provisionally, be smaller than 8% of the cascade chord.

  9. Active and Precise Control of Microdroplet Division Using Horizontal Pneumatic Valves in Bifurcating Microchannel

    Directory of Open Access Journals (Sweden)

    Shuichi Shoji

    2013-05-01

    Full Text Available This paper presents a microfluidic system for the active and precise control of microdroplet division in a micro device. Using two horizontal pneumatic valves formed at downstream of bifurcating microchannel, flow resistances of downstream channels were variably controlled. With the resistance control, volumetric ratio of downstream flows was changed and water-in-oil microdroplets were divided into two daughter droplets of different volume corresponding to the ratio. The microfluidic channels and pneumatic valves were fabricated by single-step soft lithography process of PDMS (polydimethylsiloxane using SU-8 mold. A wide range control of the daughter droplets’ volume ratio was achieved by the simple channel structure. Volumetric ratio between large and small daughter droplets are ranged from 1 to 70, and the smallest droplet volume of 14 pL was obtained. The proposed microfluidic device is applicable for precise and high throughput droplet based digital synthesis.

  10. Intelligente valve monitor for on/off control valves in process engineering; Intelligenter Grenzsignalgeber fuer Auf/Zu-Armaturen in der Prozesstechnik

    Energy Technology Data Exchange (ETDEWEB)

    Karte, Thomas; Kiesbauer, Joerg; Schaertner, Karl-Bernd [SAMSON AG, Frankfurt (Germany)

    2009-07-01

    In the article entitled ''Smart and Reliable Whether On or Off - Valve Automation Trends'' [1] of December 2007, trends in the automation of On/Off control valves were illustrated. To meet the general demand for higher plant availability, superior reliability and lower costs, both the quality and quantity of automation systems used in this field continue to advance. In this article, an actual technical solution is described. For the first time, a manufacturer succeeded in building a microcomputerbased device that is exclusively supplied with a signal according to IEC 60947-5-6 (NAMUR signal) using a two-wire supply. As a result, a new generation of devices offering new opportunities can replace the classical solenoid valves and limit switches without requiring the cabling or signal levels to be changed. Plant operators additionally benefit from enhanced functions (e.g. self-tuning and diagnostics) that, until now, only positioners provided. (orig.)

  11. Wheel Slip Control of Vehicle ABS Using Piezoactuator-Based Valve System

    Directory of Open Access Journals (Sweden)

    Juncheol Jeon

    2014-04-01

    Full Text Available This paper presents a novel piezoactuator-based valve for vehicle ABS. The piezoactuator located in one side of a rigid beam makes a displacement required to control the pressure at a flapper-nozzle of the pneumatic valve. In order to obtain the wide control range of the pressure, a pressure modulator comprised of dual-type cylinder and piston is proposed. The governing equation of the piezovalve system which consists of the proposed piezoactuator-based valve and the pressure modulator is obtained. The longitudinal vehicle dynamics and the wheel slip condition are then formulated. In order to evaluate the performance of the proposed piezovalve system from the viewpoint of the vehicle ABS, a sliding mode controller is designed for wheel slip control. The tracking control performances for the desired wheel slip rate are evaluated and the braking performances in terms of braking distance are then presented on different road conditions (dry asphalt, wet asphalt, and wet jennite. It is clearly shown that the desired wheel slip rate is well achieved and the braking distance and braking time can be significantly reduced by using the proposed piezovalve system associated with the slip rate controller.

  12. Analysis of Liquid Zone Control Valve Oscillation Problem in CANDU Reactors

    Directory of Open Access Journals (Sweden)

    Elnara Nasimi

    2013-01-01

    Full Text Available This paper looks at the existing challenges with steady-state Liquid Zone control at some CANDU (CANada Deuterium Uranium stations, where—contrary to expectations for equilibrium flow—Liquid Zone Control Valve oscillations have proven to be a chronic, unanticipated challenge. Currently, the exact causes of this behaviour are not fully understood, although it is confirmed that the Control Valve oscillations are not due to automatic power adjustment requests or zone level changes due to process leaks. This phenomenon was analysed based on a case study of one domestic nuclear power station to determine whether it could be attributed to inherent controller properties. Next, a proposal is made in an attempt to improve current performance with minimal changes to the existing system hardware and logic using conventional technologies. Finally, a proposal was made to consider Model Predictive Control-based technology to minimize the undesirable Control Valve oscillations at steady state based on the obtained simulation results and discussion of other available alternatives.

  13. Valve Disease

    Science.gov (United States)

    ... heart valves, valve insufficiency, valve regurgitation, valve stenosis, valvular heart disease Every time your heart beats, blood flows into, ... removed from the market after being linked to heart valve disease. An infection in the lining of the heart's ...

  14. The Performance Test for Reactor Coolant Pump (RCP) adopting Variable Restriction Orifice Type Control Valve

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.; Bae, B. U.; Cho, Y. J. and others

    2014-05-15

    The design values of the RCPTF are 17.2 MPa, 343 .deg. C, 11.7 m{sup 3}/s, and 13 MW in the maximum pressure, temperature, flow rate, and electrical power, respectively. In the RCPTF, various types of tests can be performed including a hydraulic performance test to acquire a H-Q curve as well seal transient tests, thrust bearing transient test, cost down test, NPSHR verification test, and so on. After a commissioning startup test was successfully perfomed, mechanical structures are improved including a flow stabilizer and variable restriction orifice. Two- branch pipe (Y-branch) was installed to regulate the flow rate in the range of performance tests. In the main pipe, a flow restrictor (RO: Restriction Orifice) for limiting the maximum flow rate was installed. In the branch pipe line, a globe valve and a butterfly valves for regulating the flow rate was located on the each branch line. When the pressure loss of the valve side is smaller than that of the RO side, the flow rate of valve side was increasing and the flow disturbance was occurred in the lower pipe line. Due to flow disturbnace, it is to cause an error when measuring RCP head and flow measurement of the venturi flow meter installed in the lower main pipe line, and thus leading to a decrease in measurement accuracy as a result. To increase the efficiency of the flow control availability of the test facility, the variable restriction orifice (VRO) type flow control valve was designed and manufactured. In the RCPTF in KAERI, the performance tests and various kinds of transient tests of the RCP were successfully performed. In this study, H-Q curve of the pump using the VRO revealed a similar trend to the result from two ROs. The VRO was confirmed to effectively cover the full test range of the flow rate.

  15. The optimum design of the pressure control spring of the relief valve based on neural networks

    Institute of Scientific and Technical Information of China (English)

    FU Xiao-jin

    2006-01-01

    Based on the traditional optimization methods about the pressure control spring of the relief valve and combined with the advantages of neural network, this paper put forward the optimization method with many parameters and a lot of constraints based on neural network. The object function of optimization is transformed into the energy function of the neural network and the mathematical model of neural network optimization about the pressure control spring of the relief valve is set up in this method which also puts forward its own algorithm. An example of application shows that network convergence gets stable state of minimization object function E, and object function converges to the utmost minimum point with steady function, then best solution is gained, which makes the design plan better. The algorithm of solution for the problem is effective about the optimum design of the pressure control spring and improves the performance target.

  16. Thermodynamic Characteristic Study of a High-temperature Flow-rate Control Valve for Fuel Supply of Scramjet Engines

    Institute of Scientific and Technical Information of China (English)

    ZENG Wen; TONG Zhizhong; LI Songjing; LI Hongzhou; ZHANG Liang

    2012-01-01

    Thermodynamic characteristics are of great importance for the performance of a high-temperature flow-rate control valve,as high-temperature environment may bring problems,such as blocking of spool and increasing of leakage,to the valve.In this paper,a high-temperature flow-rate control valve,pilot-controlled by a pneumatic servo system is developed to control the fuel supply for scramjet engines.After introducing the construction and working principle,the thermodynamic mathematical models of the valve are built based on the heat transfer methods inside the valve.By using different boundary conditions,different methods of simulations are carried out and compared.The steady-state and transient temperature field distribution inside the valve body are predicted and temperatures at five interested points are measured.By comparing the simulation and experimental results,a reasonable 3D finite element analysis method is suggested to predict the thermodynamic characteristics of the high-temperature flow-rate control valve.

  17. Development of Steam Turbine Inlet Control Valve for Supercritical Pressure at Siemens Industrial Turbomachinery AB

    OpenAIRE

    Sors, Felix; Holm, Patrik

    2010-01-01

    The development in the steam turbine business is heading for applications with much higher steam parameters since this enables a raised efficiency. Steam parameters refer to the pressure and the temperature of the steam. The aim of this study was to generate concepts for steam turbine inlet control valves designed for higher pressure and temperature in comparison with the present design. Future steam power plants using solar energy, based on tower technology, request this kind of performance ...

  18. Parameter Identification for the Valve Control Cylinder System of a Hydraulic Manipulator

    Institute of Scientific and Technical Information of China (English)

    XIE Qing-hua; PEI Wen-kai; JIANG Bin; ZHANG Qi

    2006-01-01

    In mechanical, hydraulic and electronic systems, the determination of system parameters is often challenging because liquid parameters often change significantly, due to variations in working and environmental conditions. Therefore, it is of significant practical importance to identify those parameters through experimental procedures. A systematic approach to identifying parameters in the valve controlling cylinder system of hydraulic manipulators is provided. It first derives the transfer function of the system, and then uses P control of PID control to predict system parameters. The predicted parameters are further validated using PID control. The prediction through simulation using MatLab language is utilized, which agrees well with experimental results.

  19. Modeling, Parameters Identification, and Control of High Pressure Fuel Cell Back-Pressure Valve

    Directory of Open Access Journals (Sweden)

    Fengxiang Chen

    2014-01-01

    Full Text Available The reactant pressure is crucial to the efficiency and lifespan of a high pressure PEMFC engine. This paper analyses a regulated back-pressure valve (BPV for the cathode outlet flow in a high pressure PEMFC engine, which can achieve precisely pressure control. The modeling, parameters identification, and nonlinear controller design of a BPV system are considered. The identified parameters are used in designing active disturbance rejection controller (ADRC. Simulations and extensive experiments are conducted with the xPC Target and show that the proposed controller can not only achieve good dynamic and static performance but also have strong robustness against parameters’ disturbance and external disturbance.

  20. A hybrid disturbance rejection control solution for variable valve timing system of gasoline engines.

    Science.gov (United States)

    Xie, Hui; Song, Kang; He, Yu

    2014-07-01

    A novel solution for electro-hydraulic variable valve timing (VVT) system of gasoline engines is proposed, based on the concept of active disturbance rejection control (ADRC). Disturbances, such as oil pressure and engine speed variations, are all estimated and mitigated in real-time. A feed-forward controller was added to enhance the performance of the system based on a simple and static first principle model, forming a hybrid disturbance rejection control (HDRC) strategy. HDRC was validated by experimentation and compared with an existing manually tuned proportional-integral (PI) controller. The results show that HDRC provided a faster response and better tolerance of engine speed and oil pressure variations.

  1. Aerodynamic Shutoff Valve

    Science.gov (United States)

    Horstman, Raymond H.

    1992-01-01

    Aerodynamic flow achieved by adding fixed fairings to butterfly valve. When valve fully open, fairings align with butterfly and reduce wake. Butterfly free to turn, so valve can be closed, while fairings remain fixed. Design reduces turbulence in flow of air in internal suction system. Valve aids in development of improved porous-surface boundary-layer control system to reduce aerodynamic drag. Applications primarily aerospace. System adapted to boundary-layer control on high-speed land vehicles.

  2. Design of a nanomechanical fluid control valve based on functionalized silicon cantilevers: coupling molecular mechanics with classical engineering design

    OpenAIRE

    Santiago D. Solares; Blanco, Mario; Goddard, William A.

    2004-01-01

    Process engineering design relies on a host of mechanical devices that enable transport phenomena to take place under controlled conditions. These devices include pipes, valves, pumps, chemical reactors, heat exchangers, packed columns, etc. Mass, energy, and momentum transfer will also be essential phenomena in nanoprocess engineering, particularly at the interface between micro- and nanodevices. Control valves are one of the most fundamental components. In this paper we explore the design o...

  3. Expanding Robust HCCI Operation with Advanced Valve and Fuel Control Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Szybist, J. P. [Oak Ridge National Lab., Oak Ridge, TN (United States); Confer, K. [Delphi Automotive Systems (United States)

    2012-09-11

    Delphi Automotive Systems and ORNL established this CRADA to advance the commercialization potential of the homogeneous charge compression ignition (HCCI) advanced combustion strategy for gasoline engine platforms. HCCI combustion has been shown by others to produce high diesel-like efficiency on a gasoline engine platform while simultaneously producing low NOX and particulate matter emissions. However, the commercialization barriers that face HCCI combustion are significant, with requirements for a more active engine control system, likely with next-cycle closed-loop feedback control, and with advanced valve train technologies to enable negative valve overlap conditions. In the partnership between Delphi and ORNL, each organization brought a unique and complementary set of skills to the project. Delphi has made a number of breakthroughs with production-intent valve train technologies and controls in recent years to make a part time production-intent HCCI engine plausible. ORNL has extensive knowledge and expertise with HCCI combustion, and also has a versatile research engine with hydraulic valve actuation (HVA) that is useful for guiding production of a cam-based HCCI system. Partnering these knowledge bases and capabilities was essential towards making progress to better understand HCCI combustion and the commercialization barriers that it faces. ORNL and Delphi maintained strong collaboration throughout the project. Meetings were held regularly, with additional reports, presentations, and meetings as necessary to maintain progress. Delphi provided guidance to ORNL regarding operational strategies to investigate on their single-cylinder research engine with HVA and data from their experimental multi-cylinder engine for modeling. ORNL provided single-cylinder engine data and modeling results.

  4. Sampled Data Control of a Compliant Actuated Joint Using On/Off Solenoid Valves

    Directory of Open Access Journals (Sweden)

    N. G. Tsagarakis

    2011-01-01

    Full Text Available This paper proposes a new control system design method for a compliant actuated joint using on/off solenoid valves. Themathematical modelling and the system’s hardware are described in detail. The control design method is presented in ageneral manner so it could be applied for any other similar system. For the present system, the designed controller is implementedvia a digital computer and it is characterised by very good performance and simplicity. The success of the proposedmethod is validated via simulations and experiment.

  5. Operational Experience and Consolidations for the Current Lead Control Valves of the Large Hadron Collider

    CERN Document Server

    Perin, A; Pirotte, O; Krieger, B; Widmer, A

    2012-01-01

    The Large Hadron Collider superconducting magnets are powered by more than 1400 gas cooled current leads ranging from 120 A to 13000 A. The gas flow required by the leads is controlled by solenoid proportional valves with dimensions from DN 1.8 mm to DN 10 mm. During the first months of operation, signs of premature wear were found in the active parts of the valves. This created major problems for the functioning of the current leads threatening the availability of the LHC. Following the detection of the problems, a series of measures were implemented to keep the LHC running, to launch a development program to solve the premature wear problem and to prepare for a global consolidation of the gas flow control system. This article describes first the difficulties encountered and the measures taken to ensure a continuous operation of the LHC during the first year of operation. The development of new friction free valves is then presented along with the consolidation program and the test equipment developed to val...

  6. Carpentier-Edwards aortic pericardial bioprosthetic valve as a valid control in preclinical in vivo ovine studies.

    Science.gov (United States)

    Harvey, Laura; Bianco, Richard; Lahti, Matthew; Carney, John; Zhang, Lindsey; Robinson, Nicholas

    2015-07-15

    To progress into clinical practice, a bioprosthetic heart valve must first pass through the preclinical evaluation phase. The International Standards Organization (ISO) recommends implantation of concurrent controls in any evaluation of a new or modified heart valve. A total of 8 adult sheep underwent aortic valve replacement, receiving either the CE Perimount Magna 3000 aortic pericardial bioprosthetic valve or the CE Perimount RSR aortic pericardial bioprosthetic valve, Model 2800. We performed serial blood sampling, echocardiography, angiography and necropsy after euthanasia. All 8 sheep survived until the end of their study term. Our 2-dimensional echocardiographic analysis showed a mean pressure gradient of 37.4±6.0mmHg at 14 days and 37.0±5.9mmHg at 90 days; mean cardiac output was 10.0±2.8l/min at 14 days and 9.6±1.6l/min at 90 days. Angiography before euthanasia showed a mean aortic transvalvular gradient of 32.3±15.3mmHg. At euthanasia, we saw no evidence of calcification in any of the valves. In our study, we found that both models of the CE bioprosthetic heart valve we tested proved to be valid controls, in the aortic position, in sheep-with no evidence of calcification. Most important, the valves we tested had a few model-related problems, allowing a clear determination of their suitability for introduction into a clinical trial. Investigators now have additional insight into the safety of these 2 models of valves and perhaps will be able to reduce the number of controls implanted.

  7. Controllable 0-π Josephson junctions containing a ferromagnetic spin valve

    Science.gov (United States)

    Gingrich, E. C.; Niedzielski, Bethany M.; Glick, Joseph A.; Wang, Yixing; Miller, D. L.; Loloee, Reza; Pratt, W. P., Jr.; Birge, Norman O.

    2016-06-01

    Superconductivity and ferromagnetism are antagonistic forms of order, and rarely coexist. Many interesting new phenomena occur, however, in hybrid superconducting/ferromagnetic systems. For example, a Josephson junction containing a ferromagnetic material can exhibit an intrinsic phase shift of π in its ground state for certain thicknesses of the material. Such `π-junctions' were first realized experimentally in 2001 (refs ,), and have been proposed as circuit elements for both high-speed classical superconducting computing and for quantum computing. Here we demonstrate experimentally that the phase state of a Josephson junction containing two ferromagnetic layers can be toggled between 0 and π by changing the relative orientation of the two magnetizations. These controllable 0-π junctions have immediate applications in cryogenic memory, where they serve as a necessary component to an ultralow power superconducting computer. Such a fully superconducting computer is estimated to be orders of magnitude more energy-efficient than current semiconductor-based supercomputers. Phase-controllable junctions also open up new possibilities for superconducting circuit elements such as superconducting `programmable logic', where they could function in superconducting analogues to field-programmable gate arrays.

  8. A Water Hammer Protection Method for Mine Drainage System Based on Velocity Adjustment of Hydraulic Control Valve

    Directory of Open Access Journals (Sweden)

    Yanfei Kou

    2016-01-01

    Full Text Available Water hammer analysis is a fundamental work of pipeline systems design process for water distribution networks. The main characteristics for mine drainage system are the limited space and high cost of equipment and pipeline changing. In order to solve the protection problem of valve-closing water hammer for mine drainage system, a water hammer protection method for mine drainage system based on velocity adjustment of HCV (Hydraulic Control Valve is proposed in this paper. The mathematic model of water hammer fluctuations is established based on the characteristic line method. Then, boundary conditions of water hammer controlling for mine drainage system are determined and its simplex model is established. The optimization adjustment strategy is solved from the mathematic model of multistage valve-closing. Taking a mine drainage system as an example, compared results between simulations and experiments show that the proposed method and the optimized valve-closing strategy are effective.

  9. Non-linear control of a hydraulic piezo-valve using a generalised Prandtl-Ishlinskii hysteresis model

    Science.gov (United States)

    Stefanski, Frederik; Minorowicz, Bartosz; Persson, Johan; Plummer, Andrew; Bowen, Chris

    2017-01-01

    The potential to actuate proportional flow control valves using piezoelectric ceramics or other smart materials has been investigated for a number of years. Although performance advantages compared to electromagnetic actuation have been demonstrated, a major obstacle has proven to be ferroelectric hysteresis, which is typically 20% for a piezoelectric actuator. In this paper, a detailed study of valve control methods incorporating hysteresis compensation is made for the first time. Experimental results are obtained from a novel spool valve actuated by a multi-layer piezoelectric ring bender. A generalised Prandtl-Ishlinskii model, fitted to experimental training data from the prototype valve, is used to model hysteresis empirically. This form of model is analytically invertible and is used to compensate for hysteresis in the prototype valve both open loop, and in several configurations of closed loop real time control system. The closed loop control configurations use PID (Proportional Integral Derivative) control with either the inverse hysteresis model in the forward path or in a command feedforward path. Performance is compared to both open and closed loop control without hysteresis compensation via step and frequency response results. Results show a significant improvement in accuracy and dynamic performance using hysteresis compensation in open loop, but where valve position feedback is available for closed loop control the improvements are smaller, and so conventional PID control may well be sufficient. It is concluded that the ability to combine state-of-the-art multi-layer piezoelectric bending actuators with either sophisticated hysteresis compensation or closed loop control provides a route for the creation of a new generation of high performance piezoelectric valves.

  10. Determining required valve performance for discrete control of PTO cylinders for wave energy

    DEFF Research Database (Denmark)

    Hansen, Rico Hjerm; Andersen, Torben Ole; Pedersen, Henrik C.

    2012-01-01

    Within wave energy a large challenge remains in designing a Power Take-Off (PTO) system capable of converting the slow oscillations induced by waves into electricity. Fluid power is an essential part of most PTO-concepts. To implement an efficient control of the load force produced by a cylinder...... on a floating body, throttle-less force control by discrete variation of the effective cylinder area has been investigated and found feasible for the Wavestar wave energy concept. However, the feasibility study assumes adequate valve performance, such that only the compression loss remains. This paper...

  11. Cell pairing ratio controlled micro-environment with valve-less electrolytic isolation

    KAUST Repository

    Chen, Yu-Chih

    2012-01-01

    We present a ratio controlled cell-to-cell interaction chip using valve-less isolation. We incorporated electrolysis in a microfluidic channel. In each microfluidic chamber, we loaded two types of different cells at various pairing ratios. More than 80% of the microchambers were successfully loaded with a specific target pairing ratio. For the proof of concept, we have demonstrated the cell-to-cell interaction between prostate cancer cells and muscle stem cells can be controlled by cell pairing ratios through growth factor secretion. The experimental data shows that sealing of microenvironment by air generated from electrolysis does not affect cell viability and cell interaction assay results. © 2012 IEEE.

  12. A Water Hammer Protection Method for Mine Drainage System Based on Velocity Adjustment of Hydraulic Control Valve

    OpenAIRE

    Yanfei Kou; Jieming Yang; Ziming Kou

    2016-01-01

    Water hammer analysis is a fundamental work of pipeline systems design process for water distribution networks. The main characteristics for mine drainage system are the limited space and high cost of equipment and pipeline changing. In order to solve the protection problem of valve-closing water hammer for mine drainage system, a water hammer protection method for mine drainage system based on velocity adjustment of HCV (Hydraulic Control Valve) is proposed in this paper. The mathematic mode...

  13. Application of second order sliding mode algorithms for output feedback control in hydraulic cylinder drives with profound valve dynamics

    DEFF Research Database (Denmark)

    Schmidt, Lasse; Andersen, Torben O.

    2016-01-01

    The application of second order sliding mode algorithms for output feedback control in hydraulic valve-cylinder drives appear attractive due to their simple realization and parametrization, and strong robustness toward bounded parameter variations and uncertainties. However, intrinsic nonlinear...... input signals. The application of some popular second order sliding mode controllers and their smooth counterparts are analyzed and experimentally verified. The controllers are considered for output feedback control and compared with a conventional PI control approach. The controllers under...... consideration are applied for position tracking control of a hydraulic valve-cylinder drive exhibiting strong variations in inertia- and gravitational loads, and furthermore suffer from profound valve dynamics. Results demonstrate that both the twisting- and super twisting algorithms may be successfully applied...

  14. The Use of Stepper Motor-Controlled Proportional Valve for Fio2 Calculation in the Ventilator and its Control with Fuzzy Logic.

    Science.gov (United States)

    Gölcük, Adem; Güler, İnan

    2017-01-01

    This article proposes the employment of a proportional valve that can calculate the amount of oxygen in the air to be given to patient in accordance with the amount of FiO2 which is set from the control menu of the ventilation device. To actualize this, a stepper motor-controlled proportional valve was used. Two counts of valves were employed in order to control the gases with 2 bar pressure that came from both the oxygen and medical air tanks. Oxygen and medical air manometers alongside the pressure regulators were utilized to perform this task. It is a fuzzy-logic-based controller which calculates at what rate the proportional valves will be opened and closed for FiO2 calculation. Fluidity and pressure of air given by the ventilation device were tested with a FlowMeter while the oxygen level was tested using the electronic lung model. The obtained results from the study revealed that stepper motor controlled proportional valve could be safely used in ventilation devices. In this article, it was indicated that fluidity and pressure control could be carried out with just two counts of proportional valve, which could be done with many solenoid valves, so this reduces the cost of ventilator, electrical power consumed by the ventilator, and the dimension of ventilator.

  15. A new adaptive backstepping method for nonlinear control of turbine main steam valve

    Institute of Scientific and Technical Information of China (English)

    Jun FU; Jun ZHAO

    2007-01-01

    A new approach for nonlinear adaptive control of turbine main steam valve is developed.In comparison with the existing controller based on "classical" adaptive backstepping.this method does not follow the classical certaintyequivalence principle in the design of adaptive control law.We introduce this approach,for the first time,to power systems and present a novel parameter estimator and dynamic feedback controller for a single machine infinite bus(SMIB)system with steam valve contral.This system contains unknown parameters such as reactance of transmission lines.Besides preserving useful nonlinearities and the real-time estimation of uncertain parameters,the proposed approach possesses better performances with respect to the response of the system and the speed of adaptation.The simulation results demonstrate that the proposed approach is better than the design based on "classical" adaptive backstepping in terms of properties of stability and parameter estimation,and recovers the performance of the "full-information" controller.Hence.the proposed method provides an alternative for engineers in applications.

  16. Predictive functional control of an expansion valve for minimizing the superheat of an evaporator

    Energy Technology Data Exchange (ETDEWEB)

    Fallahsohi, H.; Place, S. [EDF R and D, Av. des Renardieres, 77818 Moret-sur-Loing (France); Changenet, C. [Universite de Lyon, ECAM, Laboratoire d' Energetique, 40 Montee Saint-Barthelemy, 69321 Lyon cedex 05 (France); Ligeret, C. [Schneider-Electric, 37 Quai Paul Louis Merlin, 38050 Grenoble (France); Lin-Shi, X. [Universite de Lyon, INSA-Lyon, Ampere, CNRS UMR5005, 24 avenue Jean Capelle, 69621 Villeurbanne cedex (France)

    2010-03-15

    In a previous paper, a Predictive Functional Control (PFC) method was proposed to control the evaporator superheat with an electronic expansion valve. It has been shown that superheat may be more accurately controlled by PFC than the conventional Proportional-Integral-Derivative (PID) control. In this paper, the proposed methodology is extended to regulate the condensing pressure. In order to study the influence of this control method on the Coefficient of Performance (COP), experiments are conducted on a refrigerating machine by changing the cooling capacity from 120 to 30 kW. As PFC improves disturbance rejection compared to a PID control, it is possible to reduce the superheat setting value and to prevent any unevaporated refrigerant liquid from reaching the compressor. As a consequence the use of PFC leads to an increase of COP which depends on operating conditions. (author)

  17. State feedback integral control for a rotary direct drive servo valve using a Lyapunov function approach.

    Science.gov (United States)

    Yu, Jue; Zhuang, Jian; Yu, Dehong

    2015-01-01

    This paper concerns a state feedback integral control using a Lyapunov function approach for a rotary direct drive servo valve (RDDV) while considering parameter uncertainties. Modeling of this RDDV servovalve reveals that its mechanical performance is deeply influenced by friction torques and flow torques; however, these torques are uncertain and mutable due to the nature of fluid flow. To eliminate load resistance and to achieve satisfactory position responses, this paper develops a state feedback control that integrates an integral action and a Lyapunov function. The integral action is introduced to address the nonzero steady-state error; in particular, the Lyapunov function is employed to improve control robustness by adjusting the varying parameters within their value ranges. This new controller also has the advantages of simple structure and ease of implementation. Simulation and experimental results demonstrate that the proposed controller can achieve higher control accuracy and stronger robustness. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  18. Pressure Model of Control Valve Based on LS-SVM with the Fruit Fly Algorithm

    Directory of Open Access Journals (Sweden)

    Huang Aiqin

    2014-07-01

    Full Text Available Control valve is a kind of essential terminal control component which is hard to model by traditional methodologies because of its complexity and nonlinearity. This paper proposes a new modeling method for the upstream pressure of control valve using the least squares support vector machine (LS-SVM, which has been successfully used to identify nonlinear system. In order to improve the modeling performance, the fruit fly optimization algorithm (FOA is used to optimize two critical parameters of LS-SVM. As an example, a set of actual production data from a controlling system of chlorine in a salt chemistry industry is applied. The validity of LS-SVM modeling method using FOA is verified by comparing the predicted results with the actual data with a value of MSE 2.474 × 10−3. Moreover, it is demonstrated that the initial position of FOA does not affect its optimal ability. By comparison, simulation experiments based on PSO algorithm and the grid search method are also carried out. The results show that LS-SVM based on FOA has equal performance in prediction accuracy. However, from the respect of calculation time, FOA has a significant advantage and is more suitable for the online prediction.

  19. The Application of Differential Flow Adjustable Shuttle Valve in the Control of Ball Valve%差流可调梭阀在球阀控制中的运用

    Institute of Scientific and Technical Information of China (English)

    曾祥炜; 高树藩; 许力宏; 丁会林

    2001-01-01

    The differential flow adjustable shuttle valve is an important and fundamental device to realize pipeline automation control. The paper introduces the working prrinciple and basical performance of the shuttle valve. The site test and application have shown that this valve is available not only in controlling and adjusting the on/off time of ball valve ,but also in that of butterfly valve ,gate valve and other valves ,as well as in adjusting the flow rate and pressure of main valve.%梭控球阀是实现管道自动化控制的一个重要基础元件,介绍了其工作原理和差流可调梭阀的基本特性。差流可调梭阀不仅适用于球阀,也适用于蝶阀、闸阀和其他阀启闭时间的控制与调节,同时还可对主阀体的流量和压力进行调节。

  20. Loop Heat Pipe with Thermal Control Valve as a Variable Thermal Link

    Science.gov (United States)

    Hartenstine, John; Anderson, William G.; Walker, Kara; Dussinger, Pete

    2012-01-01

    Future lunar landers and rovers will require variable thermal links that allow for heat rejection during the lunar daytime and passively prevent heat rejection during the lunar night. During the lunar day, the thermal management system must reject the waste heat from the electronics and batteries to maintain them below the maximum acceptable temperature. During the lunar night, the heat rejection system must either be shut down or significant amounts of guard heat must be added to keep the electronics and batteries above the minimum acceptable temperature. Since guard heater power is unfavorable because it adds to system size and complexity, a variable thermal link is preferred to limit heat removal from the electronics and batteries during the long lunar night. Conventional loop heat pipes (LHPs) can provide the required variable thermal conductance, but they still consume electrical power to shut down the heat transfer. This innovation adds a thermal control valve (TCV) and a bypass line to a conventional LHP that proportionally allows vapor to flow back into the compensation chamber of the LHP. The addition of this valve can achieve completely passive thermal control of the LHP, eliminating the need for guard heaters and complex controls.

  1. Life cycle - a wide vision of the control valves maintenance; Life cycle - uma visao ampla de manutencao de valvulas de controle

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Jorge Marcos de [Metso Automation do Brasil, ES (Brazil)

    2005-07-01

    Nowadays the industry search more and more contracts which involve the total responsibility by the maintenance of its equipment. What could not be different for the control valves because of its importance and critic to the process. Because of this, the maintenance concept Life Cycle targets to involve all the phases of the life of each control valve, since the project until the day to day maintenance activities, maximizing the performance and generating benefits to the process. (author)

  2. Influence of variable valve timings on the gas exchange process in a controlled auto-ignition engine

    Energy Technology Data Exchange (ETDEWEB)

    Milovanovic, N.; Chen, R. [Loughborough University (United Kingdom). Aeronautical and Autumotive Dept.; Turner, J. [Lotus Engineering (United Kingdom). Powertrain Research Dept.

    2004-05-01

    The controlled auto-ignition (CAI) engine concept has the potential to be highly efficient and to produce low NO{sub x} and particulate matter emissions. However, the problem of controlling the combustion over the entire load/speed range limits its practical application. The CAI combustion is controlled by the chemical kinetics of the charge mixture, with no influence of the flame diffusion or turbulent propagation. Therefore, to achieve successful control of the CAI process, the composition, temperature and pressure of the charge mixture at the inlet valve closure (IC) point has to be controlled. The use of the variable valve timing strategy, which enables quick changes in the amount of trapped hot exhaust gases, shows the potential for control of CAI combustion. The aim of this paper is to analyse the influence of the variable valve timing strategy on the gas exchange process, the process between the first valve open event (EO) and the last valve closing event (IC), in a CAI engine fuelled with standard gasoline fuel (95RON). The gas exchange process affects the engine parameters and charge properties and therefore plays a crucial role in determining the control of the CAI process. Analysis is performed by experimental and modelling approaches. A single-cylinder research engine equipped with a fully variable valvetrain (FVVT ) system was used for the experimental study. A combined code consisting of a detailed chemical kinetics code and one-dimensional fluid dynamics code was used for the modelling study. The results obtained indicate that the variable valve timing strategy has a strong influence on the gas exchange process, which in turn influences the engine parameters and the cylinder charge properties, and hence the control of the CAI process. The EC timing has the strongest effect, followed by the 10 timing, while the EO and IC timings have minor effects. (author)

  3. Mesofluidic two stage digital valve

    Energy Technology Data Exchange (ETDEWEB)

    Jansen, John F; Love, Lonnie J; Lind, Randall F; Richardson, Bradley S

    2013-12-31

    A mesofluidic scale digital valve system includes a first mesofluidic scale valve having a valve body including a bore, wherein the valve body is configured to cooperate with a solenoid disposed substantially adjacent to the valve body to translate a poppet carried within the bore. The mesofluidic scale digital valve system also includes a second mesofluidic scale valve disposed substantially perpendicular to the first mesofluidic scale valve. The mesofluidic scale digital valve system further includes a control element in communication with the solenoid, wherein the control element is configured to maintain the solenoid in an energized state for a fixed period of time to provide a desired flow rate through an orifice of the second mesofluidic valve.

  4. System-medium-operated diaphragm-type control valves. Solutions for the most diverse applications; Eigenmedium gesteuerte Membranregelventile. Loesungen fuer verschiedenste Anwendungen

    Energy Technology Data Exchange (ETDEWEB)

    Dylla, Juergen [AVK Mittelmann Armaturen GmbH, Wuelfrath (Germany). Bereich Schwerarmaturen/Anlagenbau

    2008-03-15

    The following article examines system-medium-operated control valves, using the example of a specific series. Following a description of the manner of function and special design features of these valves, selected examples are cited to illustrate the range of potential applications. Diaphragm-type control valves of the range discussed are the technical leaders in terms of design, functioning, the material standards applied, and ease of operation. (orig.)

  5. Experimental and Computational Study of Two-phase (Air–Palm Oil Flow through Pipe and Control Valve in Series

    Directory of Open Access Journals (Sweden)

    Arivazhagan M.

    2009-03-01

    Full Text Available The contact of two or more immiscible liquids is encountered widely in the chemical and petroleum industries. Studies on operating characteristics of control valves with two phase flow have not been given much attention in the literature despite its industrial importance during design and selection as well as plant operations .The present work attempts to study experimentally the effect of two phase flow on pressure drop across pipe and control valve in series and compare with simulated results. Two-phase computational fluid dynamics (CFD calculations, using commercial CFD package FLUENT 6.2.16, were employed to calculate the simulated the pressure drop in Air–Palm oil flow in pipes and control valves. The Air flow rate varied from 25 to100 l/h flow rate. For constant valve position and Air flow rate, the Palm oil flow rate was varied from 50 to 150 l/h. The numerical results were validated against experimental data. The prediction of the pressure drop characteristics in pipe and valve were within an average error of about ± 3 %. A comparison of experimental and computed profiles was found to be in good agreement.

  6. Design of Electric-hydraulic Control Butterfly Valve%电液动调节蝶阀的设计

    Institute of Scientific and Technical Information of China (English)

    王建新; 张逸芳

    2014-01-01

    Introduced process design、main content and key factors to consider of the electro-hydraulic control valve ,Discusses the points for attention and suggestions of valve body,actuator,control system design and calculation.%介绍了电液动调节蝶阀方案设计的过程、主要内容及考虑的关键因素,论述了阀门本体、执行机构、控制系统等设计计算的关注点及建议。

  7. Main Oxidizer Valve Design

    Science.gov (United States)

    Addona, Brad; Eddleman, David

    2015-01-01

    A developmental Main Oxidizer Valve (MOV) was designed by NASA-MSFC using additive manufacturing processes. The MOV is a pneumatically actuated poppet valve to control the flow of liquid oxygen to an engine's injector. A compression spring is used to return the valve to the closed state when pneumatic pressure is removed from the valve. The valve internal parts are cylindrical in shape, which lends itself to traditional lathe and milling operations. However, the valve body represents a complicated shape and contains the majority of the mass of the valve. Additive manufacturing techniques were used to produce a part that optimized mass and allowed for design features not practical with traditional machining processes.

  8. Shutoff and throttling valve

    Science.gov (United States)

    Hays, L. G.

    1974-01-01

    Leaktight shutoff, precise flow control, and very low pressure drop are incorporated in all-metal valve designed for operation under extreme temperatures. Valve constructed with refractory metal is intended for control of high-temperature liquid cesium, but has applications related to control of high- and low-temperature liquids and gases.

  9. Influence of pre-injection control parameters on main-injection fuel quantity for an electronically controlled double-valve fuel injection system of diesel engine

    Science.gov (United States)

    Song, Enzhe; Fan, Liyun; Chen, Chao; Dong, Quan; Ma, Xiuzhen; Bai, Yun

    2013-09-01

    A simulation model of an electronically controlled two solenoid valve fuel injection system for a diesel engine is established in the AMESim environment. The accuracy of the model is validated through comparison with experimental data. The influence of pre-injection control parameters on main-injection quantity under different control modes is analyzed. In the spill control valve mode, main-injection fuel quantity decreases gradually and then reaches a stable level because of the increase in multi-injection dwell time. In the needle control valve mode, main-injection fuel quantity increases with rising multi-injection dwell time; this effect becomes more obvious at high-speed revolutions and large main-injection pulse widths. Pre-injection pulse width has no obvious influence on main-injection quantity under the two control modes; the variation in main-injection quantity is in the range of 1 mm3.

  10. Characterization and Testing of an Electrorheological Fluid Valve for Control of ERF Actuators

    OpenAIRE

    Quang-Anh Nguyen; Steven Jens Jorgensen; Joseph Ho; Luis Sentis

    2015-01-01

    Previous studies of electrorheological fluids (ERFs) were motivated by brake, clutch, damping, haptic and resistive applications, but never motivated towards developing an ERF based-hydraulic rotary actuator. One design to make such an actuator is to use ERF-based valves. To fully understand the performance of such an actuator, it is imperative to study ERF valves. For this reason, this paper presents a summary of design considerations for creating ERF-based actuators, an ERF-based valve desi...

  11. Pressure model of a four-way spool valve for simulating electrohydraulic control systems

    Science.gov (United States)

    Gebben, V. D.

    1976-01-01

    An equation that relates the pressure flow characteristics of hydraulic spool valves was developed. The dependent variable is valve output pressure, and the independent variables are spool position and flow. This causal form of equation is preferred in applications that simulate the effects of hydraulic line dynamics. Results from this equation are compared with those from the conventional valve equation, whose dependent variable is flow. A computer program of the valve equations includes spool stops, leakage spool clearances, and dead-zone characteristics of overlap spools.

  12. Resonance Analysis of High-Frequency Electrohydraulic Exciter Controlled by 2D Valve

    Directory of Open Access Journals (Sweden)

    Guojun Pan

    2015-01-01

    Full Text Available The resonant characteristic of hydraulic system has not been described yet because it is necessarily restricted by linear assumptions in classical fluid theory. A way of the resonance analysis is presented for an electrohydraulic exciter controlled by 2D valve. The block diagram of this excitation system is established by extracting nonlinear parts from the traditional linearization analysis; as a result the resonant frequency is obtained. According to input energy from oil source which is equal to the reverse energy to oil source, load pressure and load flow are solved analytically as the working frequency reaches the natural frequency. The analytical expression of resonant peak is also derived without damping. Finally, the experimental system is built to verify the theoretical analysis. The initial research on resonant characteristic will lay theoretical foundation and make useful complement for resonance phenomena of classical fluid theory in hydraulic system.

  13. Improved Water Network Macroscopic Model Utilising Auto-Control Adjusting Valve by PLS

    Institute of Scientific and Technical Information of China (English)

    LI Xia; ZHAO Xinhua; WANG Xiaodong

    2005-01-01

    In order to overcome the low precision and weak applicability problems of the current municipal water network state simulation model, the water network structure is studied. Since the telemetry system has been applied increasingly in the water network, and in order to reflect the network operational condition more accurately, a new water network macroscopic model is developed by taking the auto-control adjusting valve opening state into consideration. Then for highly correlated or collinear independent variables in the model, the partial least squares (PLS) regression method provides a model solution which can distinguish between the system information and the noisy data. Finally, a hypothetical water network is introduced for validating the model. The simulation results show that the relative error is less than 5.2%, indicating that the model is efficient and feasible, and has better generalization performance.

  14. Analysis of design parameters and flow characteristics of the vortex valve for SIT flow control

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Young Dong; Chang, Moon Hee; Kim, Seong O.; Kim, Young In

    1997-01-01

    This study was performed to provide a technical basis for the development of the vortex valve which will be adopted in Korean Advanced Reactor. The influence of nondimensional and geometrical parameters of the vortex valve were investigated by analyzing the flow field of the vortex chamber, and the performance related parameters were evaluated by utilizing of the published experimental and analytical data. Also the level transients of the stand pipe were investigated by using of the simplified analytical model. In order to obtain the more detailed information on the vortex flow field, three dimensional preliminary analyses for the vortex valve design were conducted by FLUENT code. This study were carried out by using the simplified analytical model of the vortex valve and downstream pipe. However, the detailed analysis on the integrated system of the vortex valve with the as built design data and the required operating conditions should be performed to obtain the more accurate results on the vortex valve behavior. Also the experimental study over a wide range of operating conditions to develop the correlation of the design parameters and the performance verification should be performed for the practical design and engineering applications of the vortex valve. The results of this study can be used as a basic information for the development of the vortex valve design for the SIT of Korean Advanced Reactor. (author). 12 refs., 5 tabs., 33 figs.

  15. The research of a new self-adjustment flow control valve%一种新型恒流量控制阀的研究

    Institute of Scientific and Technical Information of China (English)

    汤中彩; 麻剑锋; 沈新荣; 刘凯凯

    2012-01-01

    创新设计了一种机械结构简单、通流能力强、精度高的机械自力式恒流量控制阀.采用RNGk-ε湍流模型和SIMPLE算法对不同阀芯位移进行数值模拟,根据模拟结果对模型进行优化.利用自行搭建的高精度数据采样实验平台对设计的恒流量控制阀进行实验研究,实验验证该恒流量控制阀能通过线性弹簧实现高精度恒流量控制功能.%Innovatively designs a mechanical self-adjustment flow control valve model with simple mechanical structure, large flow rate and high control precision, and then numerically simulates this valve with RNGk - s turbulence model and SIMPLE method of unstructured grid under different valve core displacement, optimize the designed curve of this valve core by the outcome of pressure & valve core displacement curve of the control valve. The paper experiments the constant flow control valve model, and gains a flow rate & pressure curve of the product model, which shows it is feasible that using a linear spring to achieve a constant flow rate of the valve with high precision capability.

  16. Environmentally responsive polymeric "intelligent" materials: the ideal components of non-mechanical valves that control flow in microfluidic systems

    Directory of Open Access Journals (Sweden)

    J. Ruben Morones-Ramirez

    2010-03-01

    Full Text Available Miniaturization and commercialization of integrated microfluidic systems has had great success with the development of a wide variety of techniques in microfabrication, since they allowed their construction at a low cost and by following simple step-series procedures. However, one of the major challenges in the design of microfluidic systems is to achieve control of flow and delivery of different chemical reagents. This feature is especially important when using microfluidic systems in the development of cell culture systems, the construction of labs on a chip and the fabrication and design of chemical microreactors. Spatiotemporal control of the microenvironment in microfluidic devices has been only partially achieved by incorporating actuator parts (mechanical and non-mechanical within these devices; nevertheless, recently there has been enormous progress due to advances in the materials sciences, and the development of novel polymeric "intelligent" materials. These materials have proved to be excellent candidates in the construction of non-mechanical actuators in the form of environmentally responsive valves. These valves can more efficiently control flows because these "intelligent" materials are capable of undergoing conformational changes and phase transitions in response to different local or external environmental stimuli; allowing them to turn the valves from "on" to "off". In addition, these valves have very simple designs, and are easy and cheap to incorporate into microfluidic systems. Therefore, although there are many reviews that focus on the development and design of non-mechanical actuators, the following review proceeds to describe the exciting characteristics, potential uses and synthesis methods of the building blocks of the most recent and innovative non-mechanical valves, environmentally responsive polymeric "intelligent" materials. In addition, the last section of this review will focus on the synthesis of composite

  17. 49 CFR 179.400-19 - Valves and gages.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Valves and gages. 179.400-19 Section 179.400-19...-19 Valves and gages. (a) Valves. Manually operated shut-off valves and control valves must be... liquid flow rates. All valves must be made from approved materials compatible with the lading and...

  18. The Electronic Valve Instrument (EVI), an electronic musical wind controller for playing synthesizers

    Science.gov (United States)

    Steiner, Nyle A.

    2004-05-01

    The Electronic Valve Instrument (EVI) is an electronic musical wind instrument with playing techniques similar to that of a trumpet. Invented by Nyle Steiner in the early 1970's, it was designed to give the performer control of dynamics from breath pressure and the ability to make a humanly generated vibrato. Other musical paramaters can be controlled as well. It has a playing range of seven octaves (similar to that of a piano). When musical lines are played using this instrument (controller) connected to an electronic music synthesizer, the sound is much more natural sounding and expressive than when a normal musical keyboard is used. The evolution of this instrument from the pre-Midi era to it latest Midi configuration, principles of operation, synthesizer programming, and its wide use in movie and TV scoring will be discussed. The EVI has played featured musical lines in many major movie soundtracks and TV shows such as Apocalypse Now, Witness, Dead Poets Society, Fatal Attraction, No Way Out, Gorillas in the Mist, and many others. The EVI design has also been adapted as an Electronic Woodwind Instrument (EWI) by Nyle Steiner and has been manufactured and sold worldwide by the AKAI Co. in Japan.

  19. Miniaturization of a Quasi-Servo Valve and Its Application to Positon Control of a Rubber Artificial Muscle with Built-in Sensor

    Directory of Open Access Journals (Sweden)

    Moriwake Yoshinori

    2016-01-01

    Full Text Available Nowadays, the care and welfare pneumatic devices to support a nursing care and a self-reliance of the elderly and the disabled are actively researched and developed by many researchers. These wearable devices require many actuators and control valves for multi degrees of freedom. The total weight and volume of the wearable devices increases according to the degree of freedom. Our final goal is to develop a compact wearable actuator with built-in sensor, controller and control valve and to apply it to a wearable assisted device. In our previous study, a small-sized quasi-servo valve which consists of two on/off control valves and an embedded controller was developed. In this study, the quasi-servo valve composing of much smaller-sized (40% in mass, 42% in volume on/off valves is proposed and tested. In addition, the rubber artificial muscle with an ultrasonic sensor as a built-in displacement sensor is proposed and a position control of the muscle is carried out using the tested tiny valve and built-in sensor. As a result, it was confirmed that the position control of the muscle can be realized using the tested ultrasonic sensor.

  20. Electrolytic valving isolation of cell co-culture microenvironment with controlled cell pairing ratios.

    Science.gov (United States)

    Chen, Yu-Chih; Ingram, Patrick; Yoon, Euisik

    2014-12-21

    Cancer-stromal interaction is a critical process in tumorigenesis. Conventional dish-based co-culture assays simply mix two cell types in the same dish; thus, they are deficient in controlling cell locations and precisely tracking single cell behavior from heterogeneous cell populations. Microfluidic technology can provide a good spatial-temporal control of microenvironments, but the control has been typically realized by using external pumps, making long-term cultures cumbersome and bulky. In this work, we have presented a cell-cell interaction microfluidic platform that can accurately control the co-culture microenvironment by using a novel electrolytic cell isolation scheme without using any valves or pneumatic pumps. The proposed microfluidic platform can also precisely control the number of interacting cells and pairing ratios to emulate cancer niches. More than 80% of the chambers captured the desired number of cells. The duration of cell isolation can be adjusted by electrolytic bubble generation and removal. We have verified that the electrolytic process has a negligible effect on cell viability and proliferation in our platform. To the best of our knowledge, this work is the first attempt to incorporate electrolytic bubble generation as a cell isolation method in microfluidics. For proof of feasibility, we have performed cell-cell interaction assays between prostate cancer (PC3) cells and myoblast (C2C12) cells. The preliminary results demonstrated the potential of using electrolysis for micro-environmental control during cell culture. Also, the ratio controlled cell-cell interaction assays were successfully performed which showed that the cell pairing ratios of PC3 to C2C12 affected the proliferation rate of myoblast cells due to increased secretion of growth factors from prostate cancer cells.

  1. Modeling the Mitral Valve

    Science.gov (United States)

    Kaiser, Alexander

    2016-11-01

    The mitral valve is one of four valves in the human heart. The valve opens to allow oxygenated blood from the lungs to fill the left ventricle, and closes when the ventricle contracts to prevent backflow. The valve is composed of two fibrous leaflets which hang from a ring. These leaflets are supported like a parachute by a system of strings called chordae tendineae. In this talk, I will describe a new computational model of the mitral valve. To generate geometry, general information comes from classical anatomy texts and the author's dissection of porcine hearts. An MRI image of a human heart is used to locate the tips of the papillary muscles, which anchor the chordae tendineae, in relation to the mitral ring. The initial configurations of the valve leaflets and chordae tendineae are found by solving solving an equilibrium elasticity problem. The valve is then simulated in fluid (blood) using the immersed boundary method over multiple heart cycles in a model valve tester. We aim to identify features and mechanisms that influence or control valve function. Support from National Science Foundation, Graduate Research Fellowship Program, Grant DGE 1342536.

  2. Characterization and Testing of an Electrorheological Fluid Valve for Control of ERF Actuators

    Directory of Open Access Journals (Sweden)

    Quang-Anh Nguyen

    2015-06-01

    Full Text Available Previous studies of electrorheological fluids (ERFs were motivated by brake, clutch, damping, haptic and resistive applications, but never motivated towards developing an ERF based-hydraulic rotary actuator. One design to make such an actuator is to use ERF-based valves. To fully understand the performance of such an actuator, it is imperative to study ERF valves. For this reason, this paper presents a summary of design considerations for creating ERF-based actuators, an ERF-based valve design for an ERF actuator and a new experimental test-bed to obtain viscosity and yield characteristics of the ERF at flow rates as low as 0.049 L/min, an order of magnitude lower than industrial rheometers. The new test-bed successfully measured the dynamic viscosity of the ERF to be at 0.6 Pa-s for low flow rates and 0.2 Pa-s for higher flow rates. The presented valve design can successfully resist 1 MPa of fluid pressure, which is an operation mode higher than any haptic and damping applications in the literature. The experiments also shows that higher flow rates negatively affect the ERF’s yield characteristics for the first time in a situation where the ERF valve completely blocks flow. When the flow rates are increased, the response time to a fully-closed valve increases, the effective yield capability of the ERF decreases and the conductivity of the ERF increases.

  3. Valve selection in aortic valve endocarditis

    Science.gov (United States)

    Zubrytska, Yana

    2016-01-01

    Aortic prosthetic valve endocarditis (PVE) is a potentially life-threatening disease. Mortality and incidence of infective endocarditis have been reduced in the past 30 years. Medical treatment of aortic PVE may be successful in patients who have a prompt response after antibiotic treatment and who do not have prosthetic dysfunction. In advanced stages, antibiotic therapy alone is insufficient to control the disease, and surgical intervention is necessary. Surgical treatment may be lifesaving, but it is still associated with considerable morbidity and mortality. The aim of surgery is to perform a radical excision of all infected and necrotic tissue, reconstruction of the left ventricle outflow tract, and replacement of the aortic valve. There is no unanimous consensus on which is the optimal prosthesis to implant in this context, and several surgical techniques have been suggested. We aim to analyze the efficacy of the surgical treatment and discuss the issue of valve selection in patients with aortic valve endocarditis.

  4. Simulation and experimental control of a 3-RPR parallel robot using optimal fuzzy controller and fast on/off solenoid valves based on the PWM wave.

    Science.gov (United States)

    Moezi, Seyed Alireza; Rafeeyan, Mansour; Zakeri, Ehsan; Zare, Amin

    2016-03-01

    In this paper, a robust optimal fuzzy controller based on the Pulse Width Modulation (PWM) technique is proposed to control a laboratory parallel robot using inexpensive on/off solenoid valves. The controller coefficients are determined using Modified Cuckoo Optimization Algorithm. The objective function of this method is considered such that the results show the position tracking by the robot with less force and more efficiency. Regarding the results of experimental tests, the control strategy with on/off valves indicates good performance such that the maximum value of RMS of error for a circular path with increasing force on the system is 3.1mm. Furthermore, the results show the superiority of the optimal fuzzy controller compared with optimal PID controller in tracking paths with different conditions and uncertainties.

  5. Theoretical analysis of a pressure setting and control system with PWM direction control valve

    Science.gov (United States)

    Avram, M.; Duminică, D.; Cartal, L. A.

    2016-08-01

    The paper tackles theoretical aspects concerning an original automated system that sets and controls the pressure inside a tank chamber of fixed volume. The structure of the system integrates an original device developed and designed by the authors. The device digitally controls the one way flow of the working fluid using pulse width modulation, allowing the free flow in the other way. The purpose of this research stage was the theoretical establishing of the variation law of the pressure inside the controlled chamber.

  6. A Study on the Air Vent Valve of the Hydraulic Servo Actuator for Steam Control of Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yong Bum; Lee, Jong Jik [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2016-06-15

    To produce adequate electricity in nuclear and thermal power plants, an optimal amount of steam should be supplied to a generator connected to high- and low-pressure steam turbines. A turbine output control device, which is a special steam valve employed to supply or interrupt the steam to the turbine, is operated using a hydraulic servo actuator. In power plants, the performance of servo actuators is degraded by the air generated from the hydraulic system, or causes frequent failures owing to an increase in the wear of the seal. This is due to the seal being burnt as generated heat using the produced compressed air. Some power plants have exhausted air using a fixed orifice, and thus they encounter power loss due to mass flow exhaust. Failures are generated in hydraulic pumps, electric motors, and valves, which are frequently operated. In this study, we perform modeling and analysis of the load-sensing air-exhaust valves, which can be passed through very fine flow under normal use conditions, and exhaust mass flow air at the beginning stage as with existing fixed orifices. Then, we propose a method to prevent failures due to the compressed air, and to ensure the control accuracy of hydraulic servo actuators.

  7. Flow Characteristics of Butterfly Valve by PIV and CFD

    Science.gov (United States)

    Kim, S. W.; Kim, J. H.; Choi, Y. D.; Lee, Y. H.

    Butterfly valves are widely used as on-off and control valves for industrial process. The importance of butterfly valves as control valves has been increasing because the pressure loss is smaller than other types of valves and compactness is very desirable for installation. These features are desirable for saving energy and high efficiency of instruments.

  8. Bypass valve and coolant flow controls for optimum temperatures in waste heat recovery systems

    Science.gov (United States)

    Meisner, Gregory P

    2013-10-08

    Implementing an optimized waste heat recovery system includes calculating a temperature and a rate of change in temperature of a heat exchanger of a waste heat recovery system, and predicting a temperature and a rate of change in temperature of a material flowing through a channel of the waste heat recovery system. Upon determining the rate of change in the temperature of the material is predicted to be higher than the rate of change in the temperature of the heat exchanger, the optimized waste heat recovery system calculates a valve position and timing for the channel that is configurable for achieving a rate of material flow that is determined to produce and maintain a defined threshold temperature of the heat exchanger, and actuates the valve according to the calculated valve position and calculated timing.

  9. Valve Repair or Replacement

    Science.gov (United States)

    ... valve surgery can be done using a robot. Robotic surgery does not require a large incision in the ... The Texas Heart Institute has a robot. With robotic surgery, the surgeon has a control console, a side ...

  10. Triple-eccentric control and butterfly shut-off valves. New developments, production methods and applications; Dreifachexzentrische Regel- und Absperrklappen. Neue Entwicklungen, Produktionsverfahren und Einsatzbereiche

    Energy Technology Data Exchange (ETDEWEB)

    Knippschild, Michael [LEUSCH GmbH Industriearmaturen, Neuss (Germany)

    2009-05-15

    The triple-eccentric control and butterfly shut-off valves of the series examined in this article are individual valves precisely designed for the customer's service conditions. The large diversity of types, material variants and options makes it possible to supply the right solution for every customer requirement. Tried and proven designs, high depth of production and ultra-modern production methods assure top-quality valves which will continue to function reliably for prolonged periods even under extreme conditions in industrial processes. (orig.)

  11. Distortion of the CoreValve during transcatheter aortic valve-in-valve implantation due to valve dislocation

    Energy Technology Data Exchange (ETDEWEB)

    Souteyrand, Geraud, E-mail: gsouteyrand@chu-clermontferrand.fr [Department of Cardiology, Gabriel Montpied Hospital, CHU Clermont-Ferrand, Clermont-Ferrand (France); ERIM-EA3295, University of Auvergne, Clermont-Ferrand (France); Wilczek, Krzysztof [Department of Cardiology, Medical University of Silesia, Silesian Centre for Herat Diseases, Zabrze (Poland); Innorta, Andrea; Camilleri, Lionel [Department of Cardiology, Gabriel Montpied Hospital, CHU Clermont-Ferrand, Clermont-Ferrand (France); ERIM-EA3295, University of Auvergne, Clermont-Ferrand (France); Chodor, Piotr [Department of Cardiology, Medical University of Silesia, Silesian Centre for Herat Diseases, Zabrze (Poland); Lusson, Jean-René; Motreff, Pascal [Department of Cardiology, Gabriel Montpied Hospital, CHU Clermont-Ferrand, Clermont-Ferrand (France); ERIM-EA3295, University of Auvergne, Clermont-Ferrand (France); Laborde, Jean-Claude [St. George' s Hospital, London (United Kingdom); Chabrot, Pascal; Durel, Nicolas [Department of Cardiology, Gabriel Montpied Hospital, CHU Clermont-Ferrand, Clermont-Ferrand (France); ERIM-EA3295, University of Auvergne, Clermont-Ferrand (France)

    2013-09-15

    Nowadays transcatheter aortic valve implantation (TAVI) is an accepted alternative to surgical aortic valve replacement for high-risk patients (pts). Successful TAVI procedures for failed aortic surgical bioprosthesis (TAV-in-SAV) have already been reported. In the presented two cases of TAV-in-SAV implantation a strut distortion of the stent was revealed on angiographic imaging and confirmed on control CT scan. In both procedures, a dislocation of the medtronic core valve (MCV) prosthesis during implantation led to valve retrieval, with a necessity of reloading it in the 18F introducer before subsequent implantation of the same valve in correct position.

  12. 船用阀门遥控系统的关键技术研究%Research of Key Technologies of Marine Valve Remote Control System

    Institute of Scientific and Technical Information of China (English)

    卫少克

    2013-01-01

    With the development of global economy and marine transportation industry,marine valve system has become one of the most important equipments for large-scale,highly automated ships.The Marine valve remote control system is the key component for the marine valves control automation.In the view of the future trends of marine valve remote control system,this paper carries out a systematic study of key technologies for indirect valve position indication,integrated electro-hydraulic valve remote control etc.Moreover,the composition,structure,advantages and applicable occasions are also analyzed.%随着全球经济和海洋运输业的发展,船用阀门系统成为大型化、高度自动化船舶中必须配置的设备之一,而船用阀门遥控系统是实现船用阀门控制自动化的关键部件.针对未来船用阀门遥控系统的发展趋势,对与其相关的间接式阀位指示技术和电液集成式阀门遥控等关键技术进行了系统性的研究,分析了其内容组成、结构形式、用途优点和适用场合.

  13. Integrating bio-prosthetic valves in the Fontan operation - Novel treatment to control retrograde flow in caval veins

    Science.gov (United States)

    Vukicevic, Marija; Conover, Timothy; Zhou, Jian; Hsia, Tain-Yen; Figliola, Richard

    2012-11-01

    For a child born with only one functional heart ventricle, the sequence of palliative surgeries typically culminates in the Fontan operation. This procedure is usually successful initially, but leads to later complications, for reasons not fully understood. Examples are respiratory-dependent retrograde flows in the caval and hepatic veins, and increased pulmonary vascular resistance (PVR), hypothesized to be responsible for elevated pressure in the liver and disease of the liver and intestines. Here we study the parameters responsible for retrograde flows in the inferior vena cava (IVC) and hepatic vein (HV), and investigate two novel interventions to control retrograde flow: implanting either a Medtronic Contegra valved conduit or an Edwards lifescience pericardial aortic valve in the IVC or HV. We performed the experiments in a multi-scale, patient specific mock circuit, with normal and elevated PVR, towards the optimization of the Fontan circulation. The results show that both valves can significantly reduce retrograde flows in the veins, suggesting potential advantages in the treatment of the patients with congenital heart diseases. Fondation Leducq

  14. Bilateral Sturge-Weber Syndrome and glaucoma controlled with Ahmed valve implant

    Directory of Open Access Journals (Sweden)

    Marcelo Jarczun Kac

    2015-02-01

    Full Text Available Sturge-Weber Syndrome is a rare neuro-oculocutaneous disorder. The authors describe the case of a 13 years old boy, presented with bilateral Sturge-Weber Syndrome and glaucoma. Surgical treatment with Ahmed valve implantation in both eyes was carried out achieving lower levels of intraocular pressure.

  15. Proportional valve with a piezoelectric actuator

    Science.gov (United States)

    Laski, Pawel Andrzej

    2016-11-01

    The article concerns a slotted proportional valve for use in pneumatic and hydraulic systems. There is a growing demand for both hydraulic and pneumatic ultrafast proportional valves. The conducted analysis of literature confirms the lack of such solutions for proportional valves. The currently used pneumatic systems for selection and segregation of parts and objects require ultrafast valves. The presented solution for the proportional valve can significantly improve and accelerate this type of technological processes. Furthermore, fast proportional valves can be successfully used for positional control of pneumatic and hydraulic drives. The article presents the design of a slotted divide valve and sets the maximum mass flow rate for service roads.

  16. Proportional valve with a piezoelectric actuator

    Directory of Open Access Journals (Sweden)

    Laski Pawel Andrzej

    2017-01-01

    Full Text Available The article concerns a slotted proportional valve for use in pneumatic and hydraulic systems. There is a growing demand for both hydraulic and pneumatic ultrafast proportional valves. The conducted analysis of literature confirms the lack of such solutions for proportional valves. The currently used pneumatic systems for selection and segregation of parts and objects require ultrafast valves. The presented solution for the proportional valve can significantly improve and accelerate this type of technological processes. Furthermore, fast proportional valves can be successfully used for positional control of pneumatic and hydraulic drives. The article presents the design of a slotted divide valve and sets the maximum mass flow rate for service roads.

  17. Control of homogeneous charge compression ignition combustion in a two-cylinder gasoline direct injection engine with negative valve overlap

    Institute of Scientific and Technical Information of China (English)

    WANG Zhi; WANG Jianxin; SHUAI Shijin; MA Qingjun; TIAN Guohong

    2007-01-01

    Homogeneous charge compression ignition(HCCI) has challenges in ignition timing control,combustion rate control,and operating range extension.In this paper,HCCI combustion was studied in a two-cylinder gasoline direct injection (GDI) engine with negative valve overlap (NVO).A two-stage gasoline direct injection strategy combined with negative valve overlap was used to control mixture formation and combustion.The gasoline engine could be operated in HCCI combustion mode at a speed range of 800-2 200 r/min and load,indicated mean effective pressure (IMEP) range of 0.1-0.53 MPa.The engine fuel consumption 4× 10-5 without soot emission.The effect of different injection strategies on HCCI combustion was studied.The experimental results indicated that the coefficient of variation of the engine cycle decreased by using NVO with two-stage direct injection;the ignition timing and combustion rate could be controlled;and the operational range of HCCI combustion could be extended.

  18. Assessing the efficiency of automatically controlled valves (ACV) for pipeline sectioning

    Energy Technology Data Exchange (ETDEWEB)

    Veiga, Leandro S. da; Silva, Marcos J.M. da; Leite, Joao Paulo de B.; Santos, Renata N.R. dos; Jardim, Rodrigo B.O.; Quinto, Thiago C. do [Petrobras Transporte S.A. (TRANSPETRO), Rio de Janeiro, RJ (Brazil)

    2009-07-01

    In order to mitigate the effects caused by the rupture of a gas pipeline and following ASME B 31.8 recommendations, block valves are installed in these structures. However, many transportation companies also install devices capable of infer the occurrence of an accident in a gas pipeline. The most common devices are the ones that actuate when pressure in gas pipeline reaches a low value early established (PSL) and those which close valves due to high rate of pressure drop (line-break). Line-break has the function of identifying as fast as possible the occurrence of a rupture in a gas pipeline by high rate of pressure drop in that line. Although PSL presents a later actuation when compared to the line break, it represents redundancy to the line-break system, since it is able to isolate the segment where the accident happened even if other devices or the operator had not done it before. The growing of gas pipelines transport capacity has been generated transients capable of causing an erroneous shut down of the shut down valves (SDV). The aim of this paper, therefore, is to present how the operational limits of SDV can be overcome with remote operation using SCADA System. (author)

  19. Control valves and how to prevent them being the cause of process instability; Wie man verhindert, dass Regelventile die Ursache von Prozess-Instabilitaet werden

    Energy Technology Data Exchange (ETDEWEB)

    Grund, Tobias [Emerson Process Management GmbH und Co. OHG, Haan (Germany)

    2009-12-15

    Plant engineers and engineering managers often preside over departments that have responsibility for improving plant efficiency or availability, cutting raw material and utilities usage, or any one of a number of other Key Performance Indicators (KPIs) that are associated with the process automation equipment. In order to bring about these changes, investments are often made in the ''glamorous'' end of the business - the latest all digital control system, the newest and best advanced process control software, even higher accuracy measurement devices. This is all well and good providing the one component in the loop that moves, the control valve, is up to the job. Often overlooked, the valve has the ability to make or break any process automation investment. In this article a proven three step process is described that ensures the control valve will help reaching the achieved goals. (orig.)

  20. Design of the Modular Pneumatic Valve Terminal

    Directory of Open Access Journals (Sweden)

    Jakub E. TAKOSOGLU

    2015-11-01

    Full Text Available The paper presents design of the modular pneumatic valve terminal, which was made on the basis of the patent application No A1 402905 „A valve for controlling fluid power drives, specially for pneumatic actuators, and the control system for fluid power drives valves”. The authors describe a method of operation of the system with double-acting valve and 5/2 (five ways and two position valve. Functions of the valve, and an example of application of the valve terminal in the production process were presented. 3D solid models of all the components of the valve were made. The paper presents a complete 3D model of the valve in various configurations. Using CAD-embedded SOLIDWORKS Flow Simulation computational fluid dynamics CFD analysis was also carried out of compressed air flow in the ways of the valve elements

  1. Quality control of process valves for EPC petrochemical projects%石油化工EPC项目工艺阀门的质量控制

    Institute of Scientific and Technical Information of China (English)

    李永辉

    2013-01-01

    工艺阀门是管道元件中相对复杂的一种元件,对装置的正常运行起着十分重要的作用.简要分析了石油化工装置闸阀、截止阀、止回阀、球阀、蝶阀等常用工艺阀门的结构及优缺点,介绍了阀门在石油化工装置设计及采购时所需的主要技术参数及指标.从阀门材质、端面型式及尺寸、安装前检验试验、安装方向、施工等方面阐述了石油化工项目建设现场经常发生的阀门质量问题,并从设计、采购、施工等环节提出了解决EPC项目中存在的阀门质量问题的措施,进而达到控制阀门质量的目的.%Process valves are the complex components in pipe fittings,which play an import role in the normal operation of the unit.The construction as well as the advantages and disadvantages of common process valves like globe valve,gate valve,check valve,ball valve and butterfly valve,etc are analyzed,and the main process parameters and specifications of valves required in the engineering design and procurement of petrochemical projects are described.The common quality problems of valves in the construction sites of petrochemical projects are discussed in respect of metallurgy,end types and dimensions,quality inspection and testing before installation and installation orientation,etc.Measures to solve the valve quality problems in the engineering design,procurement and construction of EPC project are proposed to control the quality of valves.

  2. Hydraulic Equalizing Valve with Total Power Control%液压泵总功率控制的均压阀

    Institute of Scientific and Technical Information of China (English)

    杨莽; 王林

    2016-01-01

    The design and practical use of the hydraulic system, the two variable piston pump together in the same hydraulic system and to ensure consistency and to achieve the two hydraulic displacement of the total power control. The general use of two cross-pump control mode, the disadvantage is that the two hydraulic control cross consistency and total power control is poor, and it is difficult to ensure the con-sistency of the two hydraulic pumps. In this paper, by designing a pressure equalization valve to achieve the two hydraulic control. The re-sults showed that the equalizing valve can well ensure the consistency of the two hydraulic pumps and total power control.%在液压系统的设计和实际使用过程中,两台变量柱塞液压泵共同作用于同一液压系统并保证两台液压泵排量一致且要实现总功率控制.目前一般采用两台液压泵交叉控制的方式,交叉控制的缺点是两台液压泵的一致性和总功率控制效果差,且很难保证两台液压泵的一致性.该文通过设计一种均压阀,来实现两台液压泵的控制.结果表明,均压阀能够很好地保证两台液压泵的一致性和总功率控制.

  3. Design and performance characteristic analysis of servo valve-type water hydraulic poppet valve

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Hwan [Pusan National University, Busan (Korea, Republic of)

    2009-09-15

    For water hydraulic system control, the flow or pressure control using high-speed solenoid valve controlled by PWM control method could be a good solution for prevention of internal leakage. However, since the PWM control of on-off valves cause extensive flow and pressure fluctuation, it is difficult to control the water hydraulic actuators precisely. In this study, the servo valve-type water hydraulic valve using proportional poppet as the main valve is designed and the performance characteristics of the servo valve-type water hydraulic valve are analyzed. Furthermore, it is demonstrated through experiments that a decline in control chamber pressure that follows the change of pilot flow is caused by the occurrence of cavitation around the proportional poppet, and that fundamental characteristics of the developed valve remain unaffected by the occurrence of cavitation

  4. batiment SHM|SHM building|Control valves on top of a ´cold box´ for the 4K refrigeration system for the LHC |Valves de contrôle sur le dessus de la ´boite froide´ pour le système de refroidissement 4K du LHC

    CERN Multimedia

    Valeriane Duvivier

    2001-01-01

    batiment SHM|SHM building|Control valves on top of a ´cold box´ for the 4K refrigeration system for the LHC |Valves de contrôle sur le dessus de la ´boite froide´ pour le système de refroidissement 4K du LHC

  5. batiment SHM|SHM building|Control valves on top of a ´cold box´ for the 4K refrigeration system for the LHC |Valves de contrôle sur le dessus de la ´boite froide´ pour le système de refroidissement 4K du LHC

    CERN Multimedia

    Valeriane Duvivier

    2001-01-01

    batiment SHM|SHM building|Control valves on top of a ´cold box´ for the 4K refrigeration system for the LHC |Valves de contrôle sur le dessus de la ´boite froide´ pour le système de refroidissement 4K du LHC

  6. Telemedicine-guided, very low-dose international normalized ratio self-control in patients with mechanical heart valve implants.

    Science.gov (United States)

    Koertke, Heinrich; Zittermann, Armin; Wagner, Otto; Secer, Songuel; Sciangula, Alfonso; Saggau, Werner; Sack, Falk-Udo; Ennker, Jürgen; Cremer, Jochen; Musumeci, Francesco; Gummert, Jan F

    2015-06-01

    To study in patients performing international normalized ratio (INR) self-control the efficacy and safety of an INR target range of 1.6-2.1 for aortic valve replacement (AVR) and 2.0-2.5 for mitral valve replacement (MVR) or double valve replacement (DVR). In total, 1304 patients undergoing AVR, 189 undergoing MVR and 78 undergoing DVR were randomly assigned to low-dose INR self-control (LOW group) (INR target range, AVR: 1.8-2.8; MVR/DVR: 2.5-3.5) or very low-dose INR self-control once a week (VLO group) and twice a week (VLT group) (INR target range, AVR: 1.6-2.1; MVR/DVR: 2.0-2.5), with electronically guided transfer of INR values. We compared grade III complications (major bleeding and thrombotic events; primary end-points) and overall mortality (secondary end-point) across the three treatment groups. Two-year freedom from bleedings in the LOW, VLO, and VLT groups was 96.3, 98.6, and 99.1%, respectively (P = 0.008). The corresponding values for thrombotic events were 99.0, 99.8, and 98.9%, respectively (P = 0.258). The risk-adjusted composite of grade III complications was in the per-protocol population (reference: LOW-dose group) as follows: hazard ratio = 0.307 (95% CI: 0.102-0.926; P = 0.036) for the VLO group and = 0.241 (95% CI: 0.070-0.836; P = 0.025) for the VLT group. The corresponding values of 2-year mortality were = 1.685 (95% CI: 0.473-5.996; P = 0.421) for the VLO group and = 4.70 (95% CI: 1.62-13.60; P = 0.004) for the VLT group. Telemedicine-guided very low-dose INR self-control is comparable with low-dose INR in thrombotic risk, and is superior in bleeding risk. Weekly testing is sufficient. Given the small number of MVR and DVR patients, results are only valid for AVR patients. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

  7. Determination of flow-rate characteristics and parameters of piezo pilot valves

    Directory of Open Access Journals (Sweden)

    Takosoglu Jakub

    2017-01-01

    Full Text Available Pneumatic directional valves are used in most industrial pneumatic systems. Most of them are two-stage valves controlled by a pilot valve. Pilot valves are often chosen randomly. Experimental studies in order to determine the flow-rate characteristics and parameters of pilot valves were not conducted. The paper presents experimental research of two piezo pilot valves.

  8. Valve's Way

    Directory of Open Access Journals (Sweden)

    Phanish Puranam

    2015-06-01

    Full Text Available What can we learn from outliers? While statisticians rightly warn us against their non-representativeness, we believe it is also true that thinking carefully about what makes them atypical may improve our understanding of the typical case. This is the premise behind the Organization Zoo series. Valve Corporation (Valve is an unusual firm. It is a rare example of a firm that appears to operate without any formal hierarchy in its organization. What can we learn about the viability of authority hierarchies from Valve’s way of organizing? We wrote a brief account of Valve based on public information sources and asked several renowned organizational experts to comment on this unusual firm. We asked them to write a short commentary on what the Valve example means for organizational theorists and practitioners. Thankfully, they all accepted, and we are excited to present the results of their thinking in this first “exhibit” in the Organization Zoo.

  9. 气动控制阀典型附件控制原理与分析%A Typical Control Valve Attachment Theory and Analysis of Pneumatic Control

    Institute of Scientific and Technical Information of China (English)

    范贤峰

    2015-01-01

    激烈的国际性竞争促进了现代工业自动化生产过程控制的飞速发展,而气动控制阀及其控制附件是实现工业自动化生产过程的重要手段。对此,本文介绍了气动技术的基本回路以及典型的控制方案,分析并阐述典型控制回路以及相应的工作过程,这也为现代工业自动化生产过程及控制阀制造企业提供了参考和便捷的现场技术解决方案。%International competition and promote the rapid development of modern industrial production process automation and control, pneumatic control valve and its control accessories is an important means to realize industrial automation production process. Therefore, this paper introduces the basic circuit of pneumatic technology and typical control scheme, analysis and describes the typical control loop and the working process of the corresponding, this also as a modern industrial production process automation and control valve enterprises to provide on-site technical reference and convenient solution.

  10. Development of an effective valve packing program

    Energy Technology Data Exchange (ETDEWEB)

    Hart, K.A.

    1996-12-01

    Current data now shows that graphite valve packing installed within the guidance of a controlled program produces not only reliable stem sealing but predictable running loads. By utilizing recent technological developments in valve performance monitoring for both MOV`s and AOV`s, valve packing performance can be enhanced while reducing maintenance costs. Once known, values are established for acceptable valve packing loads, the measurement of actual valve running loads via the current MOV/AOV diagnostic techniques can provide indication of future valve stem sealing problems, improper valve packing installation or identify the opportunity for valve packing program improvements. At times the full benefit of these advances in material and predictive technology remain under utilized due to simple past misconceptions associated with valve packing. This paper will explore the basis for these misconceptions, provide general insight into the current understanding of valve packing and demonstrate how with this new understanding and current valve diagnostic equipment the key aspects required to develop an effective, quality valve packing program fit together. The cost and operational benefits provided by this approach can be significant impact by the: elimination of periodic valve repacking, reduction of maintenance costs, benefits of leak-free valve operation, justification for reduced Post Maintenance Test Requirements, reduced radiation exposure, improved plant appearance.

  11. Calculation of Relief Capacity of Process Safety Valve under Control Valve Failure%控制阀故障工况下安全阀泄放量的计算

    Institute of Scientific and Technical Information of China (English)

    曹虎; 周琛; 黄世勇; 王富丽

    2014-01-01

    It was one of the key factors for the selection of process safety valve (PSV), that was to accurately determine PSV discharge. In the standards,《HG/T20570.2-1995 Setting and Selection of PSV》, the formula to calculate the liquid relief capacity of PSV under control valve failure was not introduced. Basing on some engineering experiences, this paper provided a kind of calculation method to quantify the liquid relief capacity of PSV under control valve failure. Moreover, a example was illustrated to explain how to use this calculation method.%准确确定安全阀的泄放量是安全阀选型的关键之一。标准《HG/T 20570.2-1995安全阀的设置和选用》中针对控制阀故障工况下液体泄放量的计算未提供有效的计算公式。本文通过工程经验总结,提供一种控制阀故障工况下安全阀液体泄放量的计算方式,并举例说明了其使用方法。

  12. Combination throttle and shutoff valve

    Science.gov (United States)

    Carriker, J. W.

    1972-01-01

    Combination of translating sleeve throttle valve and conventional poppet valve provides capability of shutting off flow completely by poppet and sleeve control of the rate of flow. Integration of the two concepts can be accomplished without difficulty and in a manner that requires a minimum of development.

  13. Variable gas leak rate valve

    Energy Technology Data Exchange (ETDEWEB)

    Eernisse, Errol P. (Albuquerque, NM); Peterson, Gary D. (Albuquerque, NM)

    1976-01-01

    A variable gas leak rate valve which utilizes a poled piezoelectric element to control opening and closing of the valve. The gas flow may be around a cylindrical rod with a tubular piezoelectric member encircling the rod for seating thereagainst to block passage of gas and for reopening thereof upon application of suitable electrical fields.

  14. 基于FPGA的电磁阀控制设计与研究%Solenoid Valve Control Design and Research Based on FPGA

    Institute of Scientific and Technical Information of China (English)

    刘兴俊; 杨玉华; 贾兴中

    2016-01-01

    针对航空飞行器在飞行试验中需要精确控制滚控发动机电磁阀的难题,从电磁阀自身特点入手,设计了控制硬件电路并建立电磁阀门硬件电路灭弧电路响应时间模型,成功卸载60.5 V反向大电压,详细分析影响电磁阀的时间因素,同时也提出了基于FPGA的电磁阀可配置脉冲的实现方式。目前,该电磁阀控制设计已成功应用于地面发动机测试设备,具有较好的实时性、安全性和时间响应性能。%For aviation aircraft in the flight test,the precise control of the engine roller solenoid valve requires. Start⁃ing from its own characteristics solenoid valve control hardware circuit design,an interrupter arc response time mod⁃el of the solenoid valve hardware circuit is established,reverse large voltage 60.5 V successfully uninstalled,and the time factor of the solenoid valve analyzed. Based on FPGA implementations,solenoid valve can be configured by pulse matches method. Currently,the solenoid valve control design scheme has been successfully used in ground engine test equipment. It has a good real-time,security,and time response.

  15. Latest design of gate valves

    Energy Technology Data Exchange (ETDEWEB)

    Kurzhofer, U.; Stolte, J.; Weyand, M.

    1996-12-01

    Babcock Sempell, one of the most important valve manufacturers in Europe, has delivered valves for the nuclear power industry since the beginning of the peaceful application of nuclear power in the 1960s. The latest innovation by Babcock Sempell is a gate valve that meets all recent technical requirements of the nuclear power technology. At the moment in the United States, Germany, Sweden, and many other countries, motor-operated gate and globe valves are judged very critically. Besides the absolute control of the so-called {open_quotes}trip failure,{close_quotes} the integrity of all valve parts submitted to operational forces must be maintained. In case of failure of the limit and torque switches, all valve designs have been tested with respect to the quality of guidance of the gate. The guidances (i.e., guides) shall avoid a tilting of the gate during the closing procedure. The gate valve newly designed by Babcock Sempell fulfills all these characteristic criteria. In addition, the valve has cobalt-free seat hardfacing, the suitability of which has been proven by friction tests as well as full-scale blowdown tests at the GAP of Siemens in Karlstein, West Germany. Babcock Sempell was to deliver more than 30 gate valves of this type for 5 Swedish nuclear power stations by autumn 1995. In the presentation, the author will report on the testing performed, qualifications, and sizing criteria which led to the new technical design.

  16. 14 CFR 27.995 - Fuel valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel valves. 27.995 Section 27.995... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Fuel System Components § 27.995 Fuel valves. (a) There must be a positive, quick-acting valve to shut off fuel to each engine individually. (b) The control...

  17. Spin valves based on Mn{sub 75}Ir{sub 25} antiferromagnet with controllable functional parameters

    Energy Technology Data Exchange (ETDEWEB)

    Milyaev, M. A., E-mail: milyaev@imp.uran.ru; Naumova, L. I.; Kamenskii, I. Yu.; Ustinov, V. V. [Russian Academy of Sciences, Institute of Metal Physics, Ural Branch (Russian Federation)

    2015-12-15

    Using the example of spin valves of the Ta(50 Å)/Ni{sub 80}Fe{sub 20}(30 Å)/Co{sub 90}Fe{sub 10}(15 Å)/Cu(28 Å)/Co{sub 90}Fe{sub 10}(20 Å)/Mn{sub 75}Ir{sub 25}(50 Å)/Ta(20 Å) composition, factors controlling the hysteresis properties are studied for the case of macro- and microscopic sizes of an experimental sample. It is shown that a linear change in the magnetoresistance with small hysteresis while retaining the giant magnetoresistance effect at a level of 8% can be obtained in a micro-object (meander) using thermomagnetic treatment.

  18. Analysis of the Directional Control Loop Based on Cartridge Valve%二通插装阀方向控制回路分析

    Institute of Scientific and Technical Information of China (English)

    石全

    2009-01-01

    Under the development trend of hydraulic system-High pressure and large flux, the cartridge valve is more and more used. Two kinds of directional control loop composed by the Cartridge Valve are analysed in detail in this paper, that have a positive effect on understanding deeply and appalying of the Cartridge Valve.%高压、大流量是液压系统的发展趋势,二通插装阀的应用势必越来越多.本文对2种比较典型的由插装阀组成的方向控制油路进行了比较细致的分析,对加深理解和实际应用插装阀具有一定的参考价值.

  19. Cardioprotection of Electroacupuncture for Enhanced Recovery after Surgery on Patients Undergoing Heart Valve Replacement with Cardiopulmonary Bypass: A Randomized Control Clinical Trial

    Directory of Open Access Journals (Sweden)

    Fangxiang Zhang

    2017-01-01

    Full Text Available We attempted to investigate cardioprotection of electroacupuncture (EA for enhanced recovery after surgery on patients undergoing heart valve replacement with cardiopulmonary bypass. Forty-four patients with acquired heart valve replacement were randomly allocated to the EA group or the control group. Patients in the EA group received EA stimulus at bilateral Neiguan (PC6, Ximen (PC4, Shenting (GV24, and Baihui (GV20 acupoints twenty minutes before anesthesia induction to the end of surgery. The primary end point was cardioprotection effect of electroacupuncture postoperatively and the secondary endpoints were quality of recovery and cognitive functioning postoperatively. The present study demonstrated that electroacupuncture reduced the occurrence of complications and played a role of cardioprotective effect on patients after heart valve replacement surgery with cardiopulmonary bypass, and it benefits patients more comfortable and contributes to recovery after surgery. This trial is registered with ChiCTR-IOC-16009123.

  20. Analysis of Complex Valve and Feed Systems

    Science.gov (United States)

    Ahuja, Vineet; Hosangadi, Ashvin; Shipman, Jeremy; Cavallo, Peter; Dash, Sanford

    2007-01-01

    A numerical framework for analysis of complex valve systems supports testing of propulsive systems by simulating key valve and control system components in the test loop. In particular, it is designed to enhance the analysis capability in terms of identifying system transients and quantifying the valve response to these transients. This system has analysis capability for simulating valve motion in complex systems operating in diverse flow regimes ranging from compressible gases to cryogenic liquids. A key feature is the hybrid, unstructured framework with sub-models for grid movement and phase change including cryogenic cavitations. The multi-element unstructured framework offers improved predictions of valve performance characteristics under steady conditions for structurally complex valves such as pressure regulator valve. Unsteady simulations of valve motion using this computational approach have been carried out for various valves in operation at Stennis Space Center such as the split-body valve and the 10-in. (approx.25.4-cm) LOX (liquid oxygen) valve and the 4-in. (approx.10 cm) Y-pattern valve (liquid nitrogen). Such simulations make use of variable grid topologies, thereby permitting solution accuracy and resolving important flow physics in the seat region of the moving valve. An advantage to this software includes possible reduction in testing costs incurred due to disruptions relating to unexpected flow transients or functioning of valve/flow control systems. Prediction of the flow anomalies leading to system vibrations, flow resonance, and valve stall can help in valve scheduling and significantly reduce the need for activation tests. This framework has been evaluated for its ability to predict performance metrics like flow coefficient for cavitating venturis and valve coefficient curves, and could be a valuable tool in predicting and understanding anomalous behavior of system components at rocket propulsion testing and design sites.

  1. Research on Three-Phase Magnetic Valve Type Controllable Reactor%三相磁阀式可控电抗器的研究

    Institute of Scientific and Technical Information of China (English)

    李海洋; 赵国生

    2011-01-01

    提出了一种新型的三相磁阀式可控电抗器,并介绍了其结构及原理,对其进行了电磁分析。%The new three-phase magnetic valve type controllable reactor is presented.Its structure and principle are introduced.Its electromagnetic problems are analyzed.

  2. 49 CFR 236.383 - Valve locks, valves, and valve magnets.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Valve locks, valves, and valve magnets. 236.383... Inspection and Tests § 236.383 Valve locks, valves, and valve magnets. Valve locks on valves of the non-cut-off type shall be tested at least once every three months, and valves and valve magnets shall...

  3. DISAIN OTOMATISASI PROSES BVC (BASE VALVE COMPLETE ASSEMBLY PRESS BERBASIS KENDALI PROGRAMMABLE LOGIC CONTROLLER

    Directory of Open Access Journals (Sweden)

    Syahril Ardi

    2016-02-01

    Full Text Available Salah satu komponen penting dalam shock absorber adalah BVC (Base Valve Complete assembly yang merupakan komponen pengatur aliran fluida dalam shock absorber. Komponen BVC assembly ini terdiri dari 5 part berbeda yang dirakit kemudian dipress untuk menjadi satu BVC assembly. Proses press komponen BVC assembly ini dilakukan secara manual dengan menggunakan silinder pneumatik, dan tangan operator memegang BVC assembly saat proses press. Hal ini dianggap tidak safety terhadap operator, terutama mereka yang baru mengetahuinya. Untuk mengatasi hal ini, dibuatlah suatu mesin dengan menggunakan kendali PLC untuk melakukan proses press BVC assembly. Operator dibantu dengan penggunaan jig holder dalam mempersiapkan komponen BVC assembly untuk proses press. Semua pergerakan mesin dikendalikan oleh PLC Omron CPM2A secara otomatis sehingga operator hanya tinggal mempersiapkan komponen BVC assembly pada jig holder. Dengan demikian faktor safety operator dalam proses press BVC assembly dapat aman dan terkendali. Dan waktu operasional mesin press lebih stabil pada kisaran waktu 2 menit 36 detik untuk 50 kali proses press yang setiap proses press menghasilkan 2 BVC assembly.

  4. “以泵代阀”末端系统的能耗分析与系统优化%Energy consumption analysis and system optimization of replacing control valves by frequency controlled pumps in terminal system

    Institute of Scientific and Technical Information of China (English)

    潘云钢

    2011-01-01

    Taking a fresh air handling unit of central air conditioning system using replacing control valves by frequency controlled pumps as an example, calculates respective energy consumption of chilled water pump under the conditions of using electric butterfly valve, swing check valve and butterfly bivalve check valve at the outlet of chilled water pump. Analyses and compares the characteristics and energy consumption of the systems. Puts forward that replacing check valve by electric butterfly valve is in favour of decreasing energy consumption.%以集中空调系统的新风空调机组采用“以泵代阀”调节方式为例,计算水泵出口分别采用电动蝶阀、旋启式止回阀和蝶式双瓣止回阀三种不同阀件下的水泵供冷季节的能耗量,分析和比较系统的特点和能耗,提出用电动蝶阀替代止回阀有利于减少水泵能耗的观点.

  5. Piezoelectric valve

    Science.gov (United States)

    Petrenko, Serhiy Fedorovich

    2013-01-15

    A motorized valve has a housing having an inlet and an outlet to be connected to a pipeline, a saddle connected with the housing, a turn plug having a rod, the turn plug cooperating with the saddle, and a drive for turning the valve body and formed as a piezoelectric drive, the piezoelectric drive including a piezoelectric generator of radially directed standing acoustic waves, which is connected with the housing and is connectable with a pulse current source, and a rotor operatively connected with the piezoelectric generator and kinematically connected with the rod of the turn plug so as to turn the turn plug when the rotor is actuated by the piezoelectric generator.

  6. Thermostatic Radiator Valve Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Dentz, J.; Ansanelli, E.

    2015-01-01

    A large stock of multifamily buildings in the Northeast and Midwest are heated by steam distribution systems. Losses from these systems are typically high and a significant number of apartments are overheated much of the time. Thermostatically controlled radiator valves (TRVs) are one potential strategy to combat this problem, but have not been widely accepted by the residential retrofit market.

  7. A Kinematic Analysis of the Variable Valve Timing Mechanism with Three Elements and Continuous Valve Lift

    Directory of Open Access Journals (Sweden)

    Stelian Mihalcea

    2010-01-01

    Full Text Available An innovating solution for throttle-free load control for spark-ignition engines is Variable Valve Timing system (VVT System, or VVA - Variable Valve Actuation System. In this paper is presented an analytic method for kinematic analysis of the valve timing mechanism with three elements, which mainly includes the camshaft, the roller rocker finger and an intermediate rocker arm. This type of mechanism ensures a continuous valve lift (VVL System between two extreme valve heights. It is also presented the numerical example for the variable valve lift mechanism’s motion.

  8. Structure Design and Optimization of Hydraulic Control Butterfly Valve with the Heavy Hammer%重锤式液控蝶阀阀体结构设计及优化

    Institute of Scientific and Technical Information of China (English)

    郭便; 王肖烨; 魏宏波; 刘红娟; 王闯

    2012-01-01

    Taking hydraulic control butterfly valve with the heavy hammer that nominal diameter is 3. 8 m as an example, the valve body structure was designed and calculated. The optimization design that is to widen the circumference hoop of valve body was proposed. The valve body before and after optimization was analyzed by the finite element method with SolidWorks software. Results show that the optimization schemes increase the stiffness of the valve,reduce the deformation of the valve under stress, decrease the influence to the sealing performance of the valve because of the valve body deformation, and improve the sealing performance of the valve.%以公称直径为3.8m 的水电站型重锤式金属硬密封液控蝶阀为例,对阀体结构进行设计并计算,提出了对阀体的围箍加宽的优化方案,应用SolidWorks 软件对优化前后的阀体进行有限元分析.结果表明,优化方案增加了阀门的刚度,减少了阀门在承压状态下所产生的变形,从而减小因阀体变形对阀门密封性能的影响,提高了阀门的密封性能.

  9. Prediction of Flow Noise in a Controlling-valve Using CFD Method%基于CFD方法的调节阀流动噪声预测

    Institute of Scientific and Technical Information of China (English)

    王佳典; 唐浩

    2014-01-01

    Noise and vibration is a very important problem for controlling-valve performance. Aerodynamic noise is one of the most important noise sources in valve-pipe system, especially for very high fluid velocity inside the valve. In this paper, aerodynamic noise of a controlling-valve is predicted using commercial CFD software along with the acoustic software. Two computation methods based on transient CFD calculation and steady CFD calculation are used respectively in the prediction. The computation results are compared with the measurement data. The advantages and limitations of the two methods are also discussed.%阀门的噪声是阀门的重要性能指标之一。流体噪声是阀门噪声中重要的源之一,特别是阀门流速较高时,流体噪声的影响更加突出。使用计算流体力学(CFD)和声学计算方法,对某一种调节阀门的管路流体噪声使用瞬态方法和准稳态方法进行分析,并同试验的结果进行对比。对两种方法的优劣进行比较。

  10. Excess flow shutoff valve

    Energy Technology Data Exchange (ETDEWEB)

    Kiffer, Micah S.; Tentarelli, Stephen Clyde

    2016-02-09

    Excess flow shutoff valve comprising a valve body, a valve plug, a partition, and an activation component where the valve plug, the partition, and activation component are disposed within the valve body. A suitable flow restriction is provided to create a pressure difference between the upstream end of the valve plug and the downstream end of the valve plug when fluid flows through the valve body. The pressure difference exceeds a target pressure difference needed to activate the activation component when fluid flow through the valve body is higher than a desired rate, and thereby closes the valve.

  11. Vacuum Valve

    CERN Multimedia

    1974-01-01

    This valve was used in the Intersecting Storage Rings (ISR) to protect against the shock waves that would be caused if air were to enter the vacuum tube. Some of the ISR chambers were very fragile, with very thin walls - a design required by physicists on the lookout for new particles.

  12. Valve's Way

    DEFF Research Database (Denmark)

    Foss, Nicolai Juul; Dobrajska, Magdalena

    2015-01-01

    to what extent it represents a new blueprint for organization design, despite it being consistent with an “egalitarian Zeitgeist” (Puranam, 2014). In fact, managerial authority may be of increasing importance rather than the opposite (Guadalupe, Li, & Wulf, 2015). Thus, Valve is, and will remain...

  13. Valve's Way

    DEFF Research Database (Denmark)

    Foss, Nicolai Juul; Dobrajska, Magdalena

    2015-01-01

    Puranam and Håkonsson (2015) challenge us to ponder what we as organization design theorists make of Valve’s way (see also Jeppesen, 2008). We believe that Valve, in spite of its radical vision, does not represent a challenge to fundamental organization design theory and that it is questionable...

  14. Case studies of mental models in home heat control: searching for feedback, valve, timer and switch theories.

    Science.gov (United States)

    Revell, Kirsten M A; Stanton, Neville A

    2014-05-01

    An intergroup case study was undertaken to determine if: 1) There exist distinct mental models of home heating function, that differ significantly from the actual functioning of UK heating systems; and 2) Mental models of thermostat function can be categorized according to Kempton's (1986) valve and feedback shared theories, and others from the literature. Distinct, inaccurate mental models of the heating system, as well as thermostat devices in isolation, were described. It was possible to categorise thermostat models by Kempton's (1986) feedback shared theory, but other theories proved ambiguous. Alternate control devices could be categorized by Timer (Norman, 2002) and Switch (Peffer et al., 2011) theories. The need to consider the mental models of the heating system in terms of an integrated set of control devices, and to consider user's goals and expectations of the system benefit, was highlighted. The value of discovering shared theories, and understanding user mental models, of home heating, are discussed with reference to their present day relevance for reducing energy consumption. Copyright © 2013 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  15. 气压式电子驻车制动电磁阀控制特性%Characteristics of solenoid valve in electronic parking brake system control

    Institute of Scientific and Technical Information of China (English)

    黄涤; 王洪亮; 皮大伟; 石秉良; 李楠

    2016-01-01

    In order to realize the automatic control of a pneumatic parking brake system,the charging and discharging characteristics of the parking control valves and its control method is studied. Analysing the structure and working principle of a heavy duty car parking brake system,this paper designs an overall scheme of the pneumatic electronic parking brake system. The mechanical properties of the spring brake cylinder is analyzed. The charging and discharging characteristics of the electromagnetic valve is studied and compared with the traditional manual valve. The control method of the pulse width modulation( PWM) is analyzed. The relationship between the inflation rate and the PWM duty ratio of the control valve is studied. The experimental results show that the solenoid valve can preserve pressure according to the demand and can adjust the aeration rate of the solenoid valve by changing the PWM signal duty ratio.%为实现气压式驻车制动系统的自动控制,研究了驻车控制阀的充放气特性及控制方法.通过分析重型车驻车制动系统的结构及工作原理,设计了气压式电子驻车制动系统的总体方案. 分析了弹簧制动缸的力学性能,对电磁阀的快速充放气特性进行了研究,并与传统手动阀做了比较. 分析了脉冲宽度调制( Pulse width modulation,PWM)的控制方法,研究了驻车制动系统控制阀在PWM控制下占空比与充气速率的关系. 实验结果证明电磁阀可按需求保压并且可通过改变PWM信号占空比调节电磁阀充气速率.

  16. Computational Fluid Dynamics Analysis of Butterfly Valve Performance Factors

    OpenAIRE

    Del Toro, Adam

    2012-01-01

    Butterfly valves are commonly used in industrial applications to control the internal flow of both compressible and incompressible fluids. A butterfly valve typically consists of a metal disc formed around a central shaft, which acts as its axis of rotation. As the valve's opening angle is increased from 0 degrees (fully closed) to 90 degrees (fully open), fluid is able to more readily flow past the valve. Characterizing a valve's performance factors, such as pressure drop, hydrodynamic torqu...

  17. Aortic valve bypass

    DEFF Research Database (Denmark)

    Lund, Jens T; Jensen, Maiken Brit; Arendrup, Henrik

    2013-01-01

    In aortic valve bypass (AVB) a valve-containing conduit is connecting the apex of the left ventricle to the descending aorta. Candidates are patients with symptomatic aortic valve stenosis rejected for conventional aortic valve replacement (AVR) or transcatheter aortic valve implantation (TAVI...

  18. Robotic mitral valve replacement.

    Science.gov (United States)

    Senay, Sahin; Gullu, Ahmet Umit; Kocyigit, Muharrem; Degirmencioglu, Aleks; Karabulut, Hasan; Alhan, Cem

    2014-01-01

    Robotic surgical techniques allow surgeons to perform mitral valve surgery. This procedure has gained acceptance, particularly for mitral valve repair in degenerative mitral disease. However, mitral repair may not always be possible, especially in severely calcified mitral valve of rheumatic origin. This study demonstrates the basic concepts and technique of robotic mitral valve replacement for valve pathologies that are not suitable for repair.

  19. Modeling and Investigation of Electromechanical Valve Train Actuator at simulated Pressure conditions

    DEFF Research Database (Denmark)

    Habib, Tufail

    2012-01-01

    In an electromechanical valve actuated engine, the valves are driven by solenoid-type actuators and cam-shaft is eliminated. Control of each valve provides flexibility in valve timings over all engine conditions and achieves the benefits of variable valve timing(VVT). This paper is about investig...

  20. Automatic shutoff valve

    Science.gov (United States)

    Hawkins, S. F.; Overbey, C. W.

    1980-01-01

    Cellulose-sponge disk absorbs incoming water and expands with enough force to shut valve. When water recedes, valve opens by squeezing sponge dry to its original size. This direct mechanical action is considered more reliable than solenoid valve.

  1. 节流式蒸汽调节阀的改进与性能计算%Improvement and Calculation of Throttle Control Valve in Steam Turbine

    Institute of Scientific and Technical Information of China (English)

    高怡秋; 周振东; 奚骏

    2012-01-01

    蒸汽调节阀由于长期处于小流量、大压差状态下,高速汽流对滑阀表面产生了严重的冲蚀,使其无法正常工作.对调节阀提出改进措施,在低负荷工况时采用了多级小孔降压的结构.给出了多级降压的计算方法,并通过数值计算得到了改进前后的流场分布.计算结果表明改进后的结构可大幅降低汽流速度并增大总压损失系数,改善了汽流的冲蚀作用,提高了蒸汽调节阀的安全可靠性.%Due to steam control valve is under the high difference pressure and low flow conditions in a long time,the surface of the slide valve under high-speed flow has serious erosion, which does not work well. The improvement measures of control valve are proposed, that using the structure of multistage depression holes when in low load conditions. The measure of calculation of multistage depression is given, and the flow field before and after is obtained by numerical calculation. The results show that the improved structure can significantly reduce the steam velocity and increase the pressure loss coefficient,which can reform the steam flow erosion and improve the safety and reliability of the steam control valve.

  2. uVALVIT: A tool for droplet mobility control and valving

    Directory of Open Access Journals (Sweden)

    Vourdas Nikolaos

    2016-01-01

    Full Text Available Active control of droplet mobility through low cost tools is highly desirable in applications entailing microfluidics, Lab-on-Chip devices and pertinent technologies. Here, we present the design concepts of a versatile, low cost tool for dynamic droplet mobility manipulation, employing a scheme with backpressure application. Initially sticky open- or closed- channel fluidics with hydrophobic, porous walls are rendered slippery with the application of backpressure through the porous walls. Deliberate control of backpressure directs the wetting phenomena to the desired state. Operation parameters, and control system considerations are presented. Ultra-low backpressure values, are needed for channels with small cross-sections, which in turn are compatible with ultra-low energy demands.

  3. Numerical Simulation of Hydraulic Control System for Marine Butterfly Valve%船用蝶阀液压控制系统的数值仿真

    Institute of Scientific and Technical Information of China (English)

    刘辉; 戈亮; 严军

    2012-01-01

    液控蝶阀以其启闭扭矩大、压力损失小和适合用于大中口径管道等特点,在船舶领域得到了广泛应用.基于船舶中某一常用规格的中线对称阀瓣的液控蝶阀,建立该液控蝶阀在实际工况下启闭控制液压系统的数学模型,并进行数值仿真和试验研究.仿真及试验结果表明:液控蝶阀启闭时的转动角速度及其误差受蓄能器排油量、管路压力损失、液压介质的温度以及液控蝶阀的负载影响较大.这一仿真分析及试验结果可为蝶阀液压控制系统中蓄能器总容量和管路通径的选择、液控蝶阀结构型式和规格的确定及其所输送流体运动参数的设计提供依据.%Hydraulic control butterfly valve is widely used in marine area due to the following features: high torque, low pressure loss and be suitable for medium and large diameter pipeline, etc. In this paper, hydraulic control butterfly valve adopted common centerline symmetry flap, and mathematical model of the switch control hydraulic system for hydraulic control butterfly valve was established. Numerical simulation and experiment results show that; row oil of the accumulator, pipeline pressure loss, temperature of hydraulic medium and the load have great impact on the rotational angular velocity and its error when the hydraulic control valve is opening and closing. The results can be applied to selection of the total capacity of accumulator and pipeline path, and to determination of structure type and specifications for hydraulic control butterfly valve and design of the motion parameters for the fluid transported by the system.

  4. Adjustable safety relief valve

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, W.L.

    1990-06-12

    This patent describes a pressure relief valve having a relief set pressure. It comprises: a valve body having a fluid inlet and outlet, a spherical, metal valve seat associated with the inlet and a valve member comprising at least a portion of a spherical,metal ball attached to a ball holding element, the valve member being biased against the valve seat and thus providing a metal-to-metal seal preventing the passage of fluids past the valve seat when the fluid pressure in the inlet is below the relief pressure setting of the valve.

  5. Poppet valve control of throat stability bypass to increase stable airflow range of a Mach 2.5. inlet with 60 percent internal contraction

    Science.gov (United States)

    Mitchell, G. A.; Sanders, B. W.

    1975-01-01

    The throat of a Mach 2.5 inlet with a coldpipe termination was fitted with a stability-bypass system. System variations included several stability bypass entrance configurations. Poppet valves controlled the bypass airflow. The inlet stable airflow range achieved with each configuration was determined for both steady state conditions and internal pulse transients. Results are compared with those obtained without a stability bypass system. Transient results were also obtained for the inlet with a choke point at the diffuser exit and for the inlet with large and small stability bypass plenum volumes. Poppet valves at the stability bypass exit provided the inlet with a stable airflow range of 20 percent or greater at all static and transient conditions.

  6. Reducing leaks in water distribution networks. Controlling pressure by means of automatic hydraulic valves; Reduccion de fugas en redes de distribucion de agua. Control de la presion mediante valvulas hidraulicas automaticas

    Energy Technology Data Exchange (ETDEWEB)

    Singla Font, S.

    2005-07-01

    Any water distribution network, bet it of drinking water or irrigation water, always loses an inevitable amount. One of the main ways to reduce leaks is to optimise the pressure in the network by means of hydraulic valves with different types of control devices. These can be either completely hydraulic or supplemented by electronic systems. (Author)

  7. Gasoline New Timing and Flux Adjustable Rotary Valve Design (Hereinafter: Rotary Valve

    Directory of Open Access Journals (Sweden)

    Du huiqi

    2016-01-01

    Full Text Available Conventional gasoline engine with an umbrella valve control cylinder intake and exhaust, in order to achieve sealing effect, the valve is driven by the spring force; at the same time, when the cam opens the valve to overcome the spring force acting. Sealing the better, the more power consumed in the engine mechanical losses, the valve mechanism consumes about 30%, which is not a small loss! This article describes a new type of rotary valve is to significantly reduce mechanical losses, so as to achieve energy saving purposes.

  8. 3D Printed Multimaterial Microfluidic Valve

    Science.gov (United States)

    Patrick, William G.; Sharma, Sunanda; Kong, David S.; Oxman, Neri

    2016-01-01

    We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics. PMID:27525809

  9. Development of a system for monitoring and diagnosis using Fuzzy logic in control valves of laboratory test equipment of Experimental Center Aramar; Desenvolvimento de um sistema de monitoracao e diagnostico utilizando logica Fuzzy aplicado a valvulas de controle de processo do CEA - Centro Experimental Aramar

    Energy Technology Data Exchange (ETDEWEB)

    Porto Junior, Almir Carlos Soares

    2014-07-01

    The question of components reliability, specifically process control valves, has become an important issue to be investigated in nuclear power plants and other areas such as refinery or offshore oil rig, considering the safety and life extension of the plant. The development of non intrusive monitoring and diagnostic method allows the identification of defects in components of the plant during normal operation. The objective of this dissertation is to present an analysis and diagnosis of control valves of a steam plant part that simulates the secondary circuit of a pressurized water reactor. This installation is part of propulsion equipment testing laboratory of the Brazilian Navy, at Ipero-SP. The methodology for design is based on graphical analysis of two parameters, the valve air pressure actuator and the displacement of the valve plug. These data are extracted by a smart positioner, part of Delta V™ Automation System. An analysis is implemented in detecting anomalies by an approach using Expert Systems by the technique of fuzzy logic. Once the basic measures of control valves are taken, it is possible to detect symptoms of failure, leakage, friction, damage, etc. The monitoring and diagnostic system has been designed in MATLAB® version 2009{sup th} by the complement 'Fuzzy Logic Toolbox'. It is a noninvasive technique. Thus, it is possible to know what is happening with the chosen components, just analyzing the parameters of the valve. The software called ValveLink® (developed by Emerson) receives signals from hardware component (intelligent positioner) installed next to the control valve. These signals (electrical current) are transformed into information which are used input parameters: air pressure valve actuator and valve plug displacement. With the use of fuzzy logic, these parameters are interpreted. They suffer inferences by rules written by experts in valves. After these inferences, the information is processed and sent as output signals

  10. AN ACTIVE VALVE WITH A CLAMPED MEMBRANE

    DEFF Research Database (Denmark)

    2009-01-01

    An active valve for use e.g. in fluidic microsystems is provided, wherein the active valve comprises a membrane having at least one flow gate, arranged between a first and a second substantially rigid element. Adjusting means provides an adjustment of the clamping force on membrane arranged between...... the first and second substantially rigid element. Hereby the flow rate through the active valve can be continuously and precisely controlled....

  11. Bistable (latching) solenoid actuated propellant isolation valve

    Science.gov (United States)

    Wichmann, H.; Deboi, H. H.

    1979-01-01

    The design, fabrication, assembly and test of a development configuration bistable (latching) solenoid actuated propellant isolation valve suitable for the control hydrazine and liquid fluorine to an 800 pound thrust rocket engine is described. The valve features a balanced poppet, utilizing metal bellows, a hard poppet/seat interface and a flexure support system for the internal moving components. This support system eliminates sliding surfaces, thereby rendering the valve free of self generated particles.

  12. Self Adaptive Air Turbine for Wave Energy Conversion Using Shutter Valve and OWC Heoght Control System

    Energy Technology Data Exchange (ETDEWEB)

    Di Bella, Francis A

    2014-09-29

    An oscillating water column (OWC) is one of the most technically viable options for converting wave energy into useful electric power. The OWC system uses the wave energy to “push or pull” air through a high-speed turbine, as illustrated in Figure 1. The turbine is typically a bi-directional turbine, such as a Wells turbine or an advanced Dennis-Auld turbine, as developed by Oceanlinx Ltd. (Oceanlinx), a major developer of OWC systems and a major collaborator with Concepts NREC (CN) in Phase II of this STTR effort. Prior to awarding the STTR to CN, work was underway by CN and Oceanlinx to produce a mechanical linkage mechanism that can be cost-effectively manufactured, and can articulate turbine blades to improve wave energy capture. The articulation is controlled by monitoring the chamber pressure. Funding has been made available from the U.S. Department of Energy (DOE) to CN (DOE DE-FG-08GO18171) to co-share the development of a blade articulation mechanism for the purpose of increasing energy recovery. However, articulating the blades is only one of the many effective design improvements that can be made to the composite subsystems that constitute the turbine generator system.

  13. Valve timing: its effect on emissions and fuel economy

    Energy Technology Data Exchange (ETDEWEB)

    Bechtold, R.L.; Marshall, W.F.

    1977-08-01

    The effects of valve timing on exhaust emissions and fuel consumption were investigated experimentally. Emission control through the use of varied valve timing compared to conventional emissions control hardware was documented along with the effects of valve timing on emissions. Fuel consumption trends with changed valve timing were determined. The engine design of the test vehicle allowed independent adjustment of intake and exhaust valve timing. Emissions and fuel consumption were determined for steady-state speeds of 20 through 60 mph in 10 mph increments. A wide variety of intake and exhaust valve timing combinations were tested and the results compared to those of the production vehicle before modification. These results showed that valve timing has a significant effect on oxides of nitrogen emissions, but additional emissions control hardware is necessary to meet current and proposed emission regulations. Compared to emission control, varied valve timing holds more promise for reduced fuel consumption through a gain in cycle efficiency at various speeds.

  14. Valve-in-valve-in-valve: Treating endocarditis of a transcatheter heart valve.

    Science.gov (United States)

    Nguyen, Caroline; Cheong, Adrian P; Himbert, Dominique

    2015-10-01

    Transcatheter heart valve endocarditis is a rare, but life threatening complication. We describe the case of a patient who was successfully treated by transcatheter aortic valve-in-valve-in-valve replacement with a favorable 1-year outcome, despite severe early complications.

  15. Microfluidic sieve valves

    Science.gov (United States)

    Quake, Stephen R; Marcus, Joshua S; Hansen, Carl L

    2015-01-13

    Sieve valves for use in microfluidic device are provided. The valves are useful for impeding the flow of particles, such as chromatography beads or cells, in a microfluidic channel while allowing liquid solution to pass through the valve. The valves find particular use in making microfluidic chromatography modules.

  16. Remote actuated valve implant

    Energy Technology Data Exchange (ETDEWEB)

    McKnight, Timothy E.; Johnson, Anthony; Moise, Kenneth J.; Ericson, Milton Nance; Baba, Justin S.; Wilgen, John B.; Evans, Boyd Mccutchen

    2016-05-10

    Valve implant systems positionable within a flow passage, the systems having an inlet, an outlet, and a remotely activatable valve between the inlet and outlet, with the valves being operable to provide intermittent occlusion of the flow path. A remote field is applied to provide thermal or magnetic activation of the valves.

  17. Presentation of the development of the SRV valve (safety relief valve); Presentation du developpement de la vanne SRV (Safety Relief Valve)

    Energy Technology Data Exchange (ETDEWEB)

    Manguette, P. [Adareg, 59 - Haubourdin (France)

    1998-09-01

    Adareg has 30 years experience in Hydrane and control valves. Its know-how moves towards extreme technologies: control of all types of fluids (hot, cold, aggressive ones, clean ones etc... ). A perfect control is essential for very low temperatures (nuclear submarines, Ariane). Adareg Research and Development activities, certified ISO 9001, have developed valves accepting temperatures reaching 2 degrees above the absolute 0. Increasing requirements concerning low temperatures have encouraged Adareg to develop a research programme in partnership with CEA - French Atomic Energy Commission - for valves type 'SRV' (Safety Relief Valves). This type of valve is designed for a new accelerator of particles, the LHC, at CERN, in Geneva. (author)

  18. Valve-in-Valve Replacement Using a Sutureless Aortic Valve

    Science.gov (United States)

    Dohmen, Pascal M.; Lehmkuhl, Lukas; Borger, Michael A.; Misfeld, Martin; Mohr, Friedrich W.

    2016-01-01

    Patient: Female, 61 Final Diagnosis: Tissue degeneration Symptoms: Dyspnea Medication: — Clinical Procedure: Redo valve replacement Specialty: Surgery Objective: Rare disease Background: We present a unique case of a 61-year-old female patient with homograft deterioration after redo surgery for prosthetic valve endocarditis with root abscess. Case Report: The first operation was performed for type A dissection with root, arch, and elephant trunk replacement of the thoracic aorta. The present re-redo surgery was performed as valve-in-valve with a sutureless aortic biopros-thesis. The postoperative course was uneventful and the patient was discharged on day 6. Conclusions: The current case report demonstrates that sutureless bioprostheses are an attractive option for surgical valve-in-valve procedures, which can reduce morbidity and mortality. PMID:27694795

  19. A Lyapunov based nonlinear control scheme for stabilizing a basic compression system using a close-coupled control valve

    Science.gov (United States)

    Simon, J. S.; Valavani, L.

    1991-01-01

    The use of a closed-loop control to allow surge-free operation of a compression system beyond its uncontrolled surge line is addressed. In contrast to previous analyses which used a linearized model, the approach described directly addresses the nonlinear nature of the compressor characteristic using a Liapunov-based control law design formulation. The proposed approach is fairly generic and should be of interest for gas turbine engines as well as other applications.

  20. A Lyapunov based nonlinear control scheme for stabilizing a basic compression system using a close-coupled control valve

    Science.gov (United States)

    Simon, J. S.; Valavani, L.

    1991-01-01

    The use of a closed-loop control to allow surge-free operation of a compression system beyond its uncontrolled surge line is addressed. In contrast to previous analyses which used a linearized model, the approach described directly addresses the nonlinear nature of the compressor characteristic using a Liapunov-based control law design formulation. The proposed approach is fairly generic and should be of interest for gas turbine engines as well as other applications.

  1. Analysis and Reform on Reliability of Circulating Water Pump and Hydraulic-control Butterfly Valve Control System%循环水泵及液控蝶阀控制系统可靠性分析及改造

    Institute of Scientific and Technical Information of China (English)

    郭凌云

    2014-01-01

    This paper introduces and analyzes existing problems of circulating water pump and hydraulic-control butterfly valve control system in Guangdong Datang Chaozhu power plant and proposes optimization measures for improving reliabili-ty.Referred measures are feasible to greatly improve reliability of circulating water pump and hydraulic-control butterfly valve control system and safety of the unit.%对广东大唐潮州电厂循环水泵、液控蝶阀控制系统存在的问题进行了介绍和分析,并提出提高可靠性改造的优化措施。这些措施大大提高了循环水泵及液控蝶阀控制系统的可靠性及机组的安全性。

  2. Modeling and performance evaluation of an electromechanical valve actuator for a camless IC engine

    OpenAIRE

    Eid Mohamed

    2012-01-01

    Valve train control is one of the best strategies for optimizing efficiency and emissions of Internal Combustion (IC) engines. Applications of solenoid valve actuators in (IC) engines can facilitate operations such as variable valve timing and variable valve lifting for improved the engine performance, fuel economy and reduce emission, the electromechanical valve actuator (EMVA) uses solenoid to actuate valve movement independently for the application of (IC) engine. In this work presents the...

  3. Design of A Solenoid Valve Control System Based on VxWorks%一种基于 VxWorks 的电磁阀控制系统设计

    Institute of Scientific and Technical Information of China (English)

    张星; 刘巍; 张建国; 付道俊

    2016-01-01

    Solenoid valves are widely used in various control fields .As the control demand enhances ,designing a sole-noid valve control system with real-timing ,accuracy and reliability becomes a key question .This paper proposes a solenoid valve control system based on VxWorks ,describes its hardware and software design in detail .The result of tests shows that the control system is of high performance .%电磁阀广泛应用于各控制领域,随着对控制要求的不断提高,实时、准确、可靠的阀控系统是一大难题。论文提出一种基于 VxWorks 的阀件控制系统,详细介绍了其软硬件设计,并验证了其高性能。

  4. A microfluidic control system with re-usable micropump/valve actuator and injection moulded disposable polymer lab-on-a-slide

    DEFF Research Database (Denmark)

    Bu, Minqiang; Perch-Nielsen, Ivan R.; Yi, Sun

    2011-01-01

    A microfluidic control system consisting of micropump/valves with a re-usable pneumatic actuator and a disposable polymer lab-on-a-slide is presented. The lab-on-a-slide was fabricated using low cost methods, such as injection moulding of TOPAS® cyclic olefin copolymer (COC) slide, lamination...... of different layers of polymer, and ultrasonic welding of TOPAS® lid to the slide. The re-usable pneumatic actuator not only simplifies the design of the lab-on-a-slide and reduces the fabrication cost, but also reduces the possibility of cross contamination during replacement of the disposable lab...

  5. Digital hydraulic valving system. [design and development

    Science.gov (United States)

    1973-01-01

    The design and development are reported of a digital hydraulic valving system that would accept direct digital inputs. Topics include: summary of contractual accomplishments, design and function description, valve parameters and calculations, conclusions, and recommendations. The electrical control circuit operating procedure is outlined in an appendix.

  6. Comments on compressible flow through butterfly valves

    Science.gov (United States)

    Blakenship, John G.

    In the flow analysis of process piping systems, it is desirable to treat control valves in the same way as elbow, reducers, expansions, and other pressure loss elements. In a recently reported research program, the compressible flow characteristics of butterfly valves were investigated. Fisher Controls International, Inc., manufacturer of a wide range of control valves, publishes coefficients that can be used to calculate flow characteristics for the full range of valve movement. The use is described of the manufacturer's data to calculate flow parameters as reported by the researchers who investigated compressible flow through butterfly valves. The manufacturer's data produced consistent results and can be used to predict choked flow and the pressure loss for unchoked flow.

  7. Large Scale Magnetostrictive Valve Actuator

    Science.gov (United States)

    Richard, James A.; Holleman, Elizabeth; Eddleman, David

    2008-01-01

    Marshall Space Flight Center's Valves, Actuators and Ducts Design and Development Branch developed a large scale magnetostrictive valve actuator. The potential advantages of this technology are faster, more efficient valve actuators that consume less power and provide precise position control and deliver higher flow rates than conventional solenoid valves. Magnetostrictive materials change dimensions when a magnetic field is applied; this property is referred to as magnetostriction. Magnetostriction is caused by the alignment of the magnetic domains in the material s crystalline structure and the applied magnetic field lines. Typically, the material changes shape by elongating in the axial direction and constricting in the radial direction, resulting in no net change in volume. All hardware and testing is complete. This paper will discuss: the potential applications of the technology; overview of the as built actuator design; discuss problems that were uncovered during the development testing; review test data and evaluate weaknesses of the design; and discuss areas for improvement for future work. This actuator holds promises of a low power, high load, proportionally controlled actuator for valves requiring 440 to 1500 newtons load.

  8. 30 CFR 57.4603 - Closure of valves.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Closure of valves. 57.4603 Section 57.4603... Control Welding/cutting/compressed Gases § 57.4603 Closure of valves. To prevent accidental release of... or manifold system valves shall be closed when— (a) The cylinders are moved; (b) The torch and...

  9. 30 CFR 56.4603 - Closure of valves.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Closure of valves. 56.4603 Section 56.4603... Control Welding/cutting/compressed Gases § 56.4603 Closure of valves. To prevent accidental release of... or manifold system valves shall be closed when— (a) The cylinders are moved; (b) The torch and...

  10. 46 CFR 169.746 - Fuel shutoff valves.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Fuel shutoff valves. 169.746 Section 169.746 Shipping... Control, Miscellaneous Systems, and Equipment Markings § 169.746 Fuel shutoff valves. Each remote fuel shutoff station must be marked in at least 1-inch letters indicating purpose of the valves and...

  11. Which valve is which?

    Directory of Open Access Journals (Sweden)

    Pravin Saxena

    2015-01-01

    Full Text Available A 25-year-old man presented with a history of breathlessness for the past 2 years. He had a history of operation for Tetralogy of Fallot at the age of 5 years and history suggestive of Rheumatic fever at the age of 7 years. On echocardiographic examination, all his heart valves were severely regurgitating. Morphologically, all the valves were irreparable. The ejection fraction was 35%. He underwent quadruple valve replacement. The aortic and mitral valves were replaced by metallic valve and the tricuspid and pulmonary by tissue valve.

  12. AeroValve Experimental Test Data Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Noakes, Mark W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-09-01

    This report documents the collection of experimental test data and presents performance characteristics for the AeroValve brand prototype pneumatic bidirectional solenoid valves tested at the Oak Ridge National Laboratory (ORNL) in July/August 2014 as part of a validation of AeroValve energy efficiency claims. The test stand and control programs were provided by AeroValve. All raw data and processing are included in the report attachments.

  13. 智能化控制阀在石油化工中的应用设计%Application Design of Intelligent Control Valve in Petrochemical Industry

    Institute of Scientific and Technical Information of China (English)

    王浩

    2015-01-01

    阀门是流体管路的控制装置,它的基本功能是接通或切断管路介质的流通,改变介质的流动方向,调节介质的压力和流量,保护管路和设备的正常运行.随着科技的发展,智能控制被广泛应用于工业控制和工业生产中,阀门也被广泛应用于工业、建筑、农业、国防、科研和人们的日常生活中.它由最初的手动控制逐渐发展为智能化、标准化、小型化、安全化的控制,在生产中替代人力操作,使控制更精确、更合理、更安全.从控制阀智能化方面的内容入手,简要阐述了其在石油化工中的应用.%The valve is the control device of the fluid pipeline, its basic function is to connect or cut off the flow of the pipeline medium, changing the flow direction of the medium, adjust the pressure and flow of the media, and protect the normal operation of the pipeline and equipment. With the development of science and technology, intelligent control is widely used in industrial control and industrial production, the valve is widely used in industrial, construction, agriculture, national defense, scientific research and people's daily life. It is gradually developed from the initial manual control to intelligent, standardized, small, safe control, in the production of alternative human operation, so that control more accurate, more reasonable and more secure. In this paper, the content of intelligent control valve is discussed, and its application in petrochemical industry is briefly described.

  14. Hydraulic System Design of Hydraulic Actuators for Large Butterfly Valves

    OpenAIRE

    HUANG, Ye; Liu, Changsheng; Shiongur Bamed

    2014-01-01

    Hydraulic control systems of butterfly valves are presently valve-controlled and pump-controlled. Valve-controlled hydraulic systems have serious power loss and generate much heat during throttling. Pump-controlled hydraulic systems have no overflow or throttling losses but are limited in the speed adjustment of the variable-displacement pump, generate much noise, pollute the environment, and have motor power that does not match load requirements, resulting in low efficiency under...

  15. Aortic Valve Regurgitation

    Science.gov (United States)

    ... inside your heart that involves heart valves. Rheumatic fever. Rheumatic fever — a complication of strep throat and once a ... the United States — can damage the aortic valve. Rheumatic fever is still prevalent in developing countries but rare ...

  16. Pulmonary Valve Stenosis

    Science.gov (United States)

    ... growths called carcinoid tumors in the digestive system. Rheumatic fever. This complication of an infection caused by streptococcus ... valve stenosis later in life, including: Carcinoid syndrome Rheumatic fever Noonan's syndrome Mild to moderate pulmonary valve stenosis ...

  17. Aortic Valve Disease

    Science.gov (United States)

    ... Tricuspid Valve Disease Cardiac Rhythm Disturbances Thoracic Aortic Aneurysm Pediatric and Congenital Heart Disease Heart abnormalities that are ... Transplantation End-stage Lung Disease Adult Lung Transplantation Pediatric Lung ... Aortic Aneurysm Aortic Valve Disease Overview The human heart has ...

  18. Mitral Valve Stenosis

    Science.gov (United States)

    ... up around the ring around the mitral valve (annulus), which can occasionally cause mitral valve stenosis. Other ... the condition of your lungs. Transesophageal echocardiogram. A small transducer attached to the end of a tube ...

  19. Heart valve surgery

    Science.gov (United States)

    ... Tricuspid valve stenosis Risks The risks of having cardiac surgery include: Death Heart attack Heart failure Bleeding requiring ... and the A.D.A.M. Editorial team. Heart Surgery Read more Heart Valve Diseases Read more Latest ...

  20. Combined pressure regulator and shutoff valve

    Science.gov (United States)

    Koch, E. F. (Inventor)

    1974-01-01

    A remotely operable pressure regulator and shutoff valve particularly suited for achieving high resolution and flow control, and positive shutoff is described. The valve is characterized by a spring-loaded ball coaxially aligned with a fluid port to be sealed, a spring-loaded pintle extended through the port into engagement with the ball, for controlling the position, a spring-loaded diaphragm for controlling the position of the pintle, and an axially displaceable spring supported by a movable stop which, in turn, is repositioned by a selectively operable stepper motor. Thus, the pressure-response characteristics for the valve can be varied through a selective repositioning of the stop.

  1. 液控单向阀在锁紧回路中的控制特性研究%Study on Control Characteristics of Hydraulic Control One-way Valve in Locking Circuit

    Institute of Scientific and Technical Information of China (English)

    苏沛群; 邓志辉; 张西良

    2014-01-01

    Aiming at the different installation positions of hydraulic control one-way valve in hydraulic locking circuit,based on the analysis to the opening necessary conditions and the opening control pressure under different working conditions of hydraulic control one-way valve,the idea was put forward that opening pressure of hydraulic control one-way valve was maximum when the hydraulic oil went into the chamber without rod,backed to the chamber with rod and the hydraulic cylinder subjected to reversed load. The relation between control pressure and the load of the hydraulic cylinder,the relation between structure parameters M of hydraulic control valve, the speed ratioφof hydraulic cylinder and oil resistanceΔp were described. Speed ratioφof the hydraulic cylinder is bigger,the open-ing pressure is greater;the structure parameter M of the hydraulic control one-way valve is larger,the opening pressure is smaller.%针对液控单向阀在液压锁紧回路中的不同安装位置,在分析不同工况下液控单向阀开启的必要条件和开启工作时的控制压力的基础上,提出液压缸无杆腔进油、有杆腔回油且液压缸承受反向负载时液控单向阀开启压力最大的理念,阐述了控制压力与液压缸的负载、液控单向阀的结构参数M、液压缸的速比φ和回油阻力Δp的关系,从而得出液压缸的速比φ越大、开启压力越大,液控单向阀的结构参数M越大、开启压力越小的结论。

  2. Studies for the requirements of automatic and remotely controlled shutoff valves on hazardous liquids and natural gas pipelines with respect to public and environmental safety

    Energy Technology Data Exchange (ETDEWEB)

    Oland, C. Barry [XCEL Engineering, Inc. (United States); Rose, Simon D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Engineering Science and Technology Div.; Grant, Herb L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fabrication, Hoisting and Rigging Div.; Lower, Mark D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fabrication, Hoisting and Rigging Div.; Spann, Mark A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Facility Management Div.; Kirkpatrick, John R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Computational Sciences and Engineering Div.; Sulfredge, C. David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Computational Sciences and Engineering Div.

    2012-12-01

    This study assesses the effectiveness of block valve closure swiftness in mitigating the consequences of natural gas and hazardous liquid pipeline releases on public and environmental safety. It also evaluates the technical, operational, and economic feasibility and potential cost benefits of installing automatic shutoff valves (ASVs) and remote control valves (RCVs) in newly constructed and fully replaced transmission lines. Risk analyses of hypothetical pipeline release scenarios are used as the basis for assessing: (1) fire damage to buildings and property in Class 1, Class 2, Class 3, and Class 4 high consequence areas (HCAs) caused by natural gas pipeline releases and subsequent ignition of the released natural gas; (2) fire damage to buildings and property in HCAs designated as high population areas and other populated areas caused by hazardous liquid pipeline releases and subsequent ignition of the released propane; and (3) socioeconomic and environmental damage in HCAs caused by hazardous liquid pipeline releases of crude oil. These risk analyses use engineering principles and fire science practices to characterize thermal radiation effects on buildings and humans and to quantify the total damage cost of socioeconomic and environmental impacts. The risk analysis approach used for natural gas pipelines is consistent with risk assessment standards developed by industry and incorporated into Federal pipeline safety regulations. Feasibility evaluations for the hypothetical pipeline release scenarios considered in this study show that installation of ASVs and RCVs in newly constructed and fully replaced natural gas and hazardous liquid pipelines is technically, operationally, and economically feasible with a positive cost benefit. However, these results may not apply to all newly constructed and fully replaced pipelines because site-specific parameters that influence risk analyses and feasibility evaluations often vary significantly from one pipeline segment to

  3. Isolated Pulmonary Valve Endocarditis

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Hatamizadeh

    2009-06-01

    Full Text Available Infective endocarditis is one of the most severe complications of parenteral drug abuse. The outstanding clinical feature of infective endocarditis in intravenous drug abusers is the high incidence of right-sided valve infection, and the tricuspid valve is involved in 60% to 70% of the cases. We herein report a case of isolated pulmonic valve infective endocarditis with a native pulmonary valve.

  4. Fast-acting valve actuator

    Science.gov (United States)

    Cho, Nakwon

    1980-01-01

    A fast-acting valve actuator utilizes a spring driven pneumatically loaded piston to drive a valve gate. Rapid exhaust of pressurized gas from the pneumatically loaded side of the piston facilitates an extremely rapid piston stroke. A flexible selector diaphragm opens and closes an exhaust port in response to pressure differentials created by energizing and de-energizing a solenoid which controls the pneumatic input to the actuator as well as selectively providing a venting action to one side of the selector diaphragm.

  5. Propellant isolation shutoff valve program

    Science.gov (United States)

    Merritt, F. L.

    1973-01-01

    An analysis and design effort directed to advancing the state-of-the-art of space storable isolation valves for control of flow of the propellants liquid fluorine/hydrazine and Flox/monomethylhydrazine is discussed. Emphasis is on achieving zero liquid leakage and capability of withstanding missions up to 10 years in interplanetary space. Included is a study of all-metal poppet sealing theory, an evaluation of candidate seal configurations, a valve actuator trade-off study and design description of a pneumo-thermally actuated soft metal poppet seal valve. The concepts and analysis leading to the soft seal approach are documented. A theoretical evaluation of seal leakage versus seal loading, related finishes and yield strengths of various materials is provided. Application of a confined soft aluminum seal loaded to 2 to 3 times yield strength is recommended. Use of either an electro-mechanical or pneumatic actuator appears to be feasible for the application.

  6. Heart Valve Diseases

    Science.gov (United States)

    Your heart has four valves. Normally, these valves open to let blood flow through or out of your heart, and then shut to keep it from flowing ... close tightly. It's one of the most common heart valve conditions. Sometimes it causes regurgitation. Stenosis - when ...

  7. Dump valve assembly

    Science.gov (United States)

    Owen, T.J.

    1984-01-01

    A dump valve assembly comprising a body having a bore defined by a tapered wall and a truncated spherical valve member adapted to seat along a spherical surface portion thereof against said tapered wall. Means are provided for pivoting said valve member between a closed position engagable with said tapered wall and an open position disengaged therefrom.

  8. Quadricuspid Aortic Valve

    Directory of Open Access Journals (Sweden)

    Mehmet Taşar

    2013-03-01

    Full Text Available Quadricuspid aortic valve is an extremely rare congenital defect. Isolated form appears frequently. It is seen with aortic valve regurgitation in adulthood. This case report presents a rare clinical finding of an isolated quadricuspid aortic valve with aortic regurgitation in an 64-year-old female who was referred for cardiac evaluation due to newly identified murmur.

  9. Technical evaluation of the electrical, instrumentation, and control design aspects of the override of containment purge valve isolation and other engineered safety feature signals for the Fort Calhoun Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Hackett, D.B.

    1980-01-01

    This report documents the technical evaluation of the electrical, instrumentation, and control design aspects of the override of containment purge valve isolation and other engineered safety feature signals for the Fort Calhoun nuclear power plant. The review criteria are based on IEEE Std-279-1971 requirements for the safety signals to all purge and ventilation isolation valves. This report is supplied as part of the Selected Electrical, Instrumentation, and Control Systems Issues Program being conducted for the US Nuclear Regulatory Commission by Lawrence Livermore Laboratory.

  10. Artificial SMA valve for treatment of urinary incontinence: upgrading of valve and introduction of transcutaneous transformer.

    Science.gov (United States)

    Tanaka, M; Hirano, K; Goto, H; Namima, T; Uchi, K; Jiang, Z W; Matsuki, H; Tanahashi, Y; Orikasa, S; Chonan, S

    1999-01-01

    This paper is concerned with the development of an artificial urethral valve driven by shape memory alloy actuators, which is attached onto the urethra of a urinary incontinence sufferer for treating the involuntary micturition. Three types of compact cylindrical valves are assembled and their opening and closing functions are examined experimentally. The updated valve is heated and opened by using the transcutaneous energy transformer consisting of a pair of flexible spiral-formed copper wire coils. The experiment using the canine urinary canal verifies that the total system of the valve and the transformer works well as an artificial sphictor muscle and controls the urinary flow through the canal appropriately.

  11. D-dimer to guide the intensity of anticoagulation in Chinese patients after mechanical heart valve replacement: a randomized controlled trial.

    Science.gov (United States)

    Zhang, L; Zheng, X; Long, Y; Wu, M; Chen, Y; Yang, J; Liu, Z; Zhang, Z

    2017-08-01

    Essentials Low anticoagulation intensity reduces bleeding but increases thrombosis during warfarin therapy. Elevated D-dimer level is associated with increased thrombosis events. D-dimer can be used to find potential thrombosis in those receiving low intensity therapy. D-dimer-guided therapy may be the optimal strategy for those with mechanical heart valve replacement. Background Controversies remain regarding the optimal anticoagulation intensity for Chinese patients after mechanical heart valve replacement despite guidelines having recommended a standard anticoagulation intensity. Objectives To investigate whether D-dimer could be used to determine the optimal anticoagulation intensity in Chinese patients after mechanical heart valve replacement. Patients/Methods This was a prospective, randomized controlled clinical study. A total of 748 patients following mechanical heart valve replacement in Wuhan Asia Heart Hospital were randomized to three groups at a ratio of 1 : 1 : 1. Patients in two control groups received warfarin therapy based on constant standard intensity (international normalized ratio [INR], 2.5-3.5; n = 250) and low intensity (INR, 1.8-2.6; n = 248), respectively. In the experimental group (n = 250), warfarin therapy was initiated at low intensity, then those with elevated D-dimer levels were adjusted to standard intensity. All patients were followed-up for 24 months until the occurrence of endpoints, including bleeding events, thrombotic events and all-cause mortality. Results A total of 718 patients were included in the analysis. Fifty-three events occurred during follow-up. There was less hemorrhage (3/240 vs. 16/241; hazard ratio [HR], 0.18; 95% confidence interval [CI], 0.07-0.45) and all-cause mortality (4/240 vs. 12/241; HR, 0.33; 95% CI, 0.12-0.87) observed in the D-dimer-guided group than in the standard-intensity group. A lower incidence of thrombotic events was also observed in the D-dimer-guided group when compared with the

  12. Multidisciplinary optimization of a butterfly valve.

    Science.gov (United States)

    Song, Xue Guan; Wang, Lin; Baek, Seok Heum; Park, Young Chul

    2009-07-01

    A butterfly valve is a type of flow control device, typically used to regulate fluid flow. This paper proposes a new process to meet desired needs in valve design that is characterized by the complex configuration. First, the need is identified according to the valve user/company, and then the problem is defined with a characteristic function. Second, the initial model of valve is made, and then the initial analysis including fluid and/or structural analysis is carried out to predict the fluid and/or structural performance of the valve. Third, the optimization in the form of mathematical functions, which considers single or multiple objective and/or discipline, is handled. This part includes the design of computer experiment, approximation technique, topology optimization and sizing optimization. Finally, the validation experiment is conducted based on the optimum result to verify the accuracy of the optimization. An example is provided to confirm the availability of the process proposed here.

  13. Oil pipeline valve automation for spill reduction

    Energy Technology Data Exchange (ETDEWEB)

    Mohitpour, Mo; Trefanenko, Bill [Enbridge Technology Inc, Calgary (Canada); Tolmasquim, Sueli Tiomno; Kossatz, Helmut [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil)

    2003-07-01

    Liquid pipeline codes generally stipulate placement of block valves along liquid transmission pipelines such as on each side of major river crossings where environmental hazards could cause or are foreseen to potentially cause serious consequences. Codes, however, do not stipulate any requirement for block valve spacing for low vapour pressure petroleum transportation, nor for remote pipeline valve operations to reduce spills. A review of pipeline codes for valve requirement and spill limitation in high consequence areas is thus presented along with a criteria for an acceptable spill volume that could be caused by pipeline leak/full rupture. A technique for deciding economically and technically effective pipeline block valve automation for remote operation to reduce oil spilled and control of hazards is also provided. In this review, industry practice is highlighted and application of the criteria for maximum permissible oil spill and the technique for deciding valve automation thus developed, as applied to ORSUB pipeline is presented. ORSUB is one of the three initially selected pipelines that have been studied. These pipelines represent about 14% of the total length of petroleum transmission lines operated by PETROBRAS Transporte S.A. (TRANSPETRO) in Brazil. Based on the implementation of valve motorization on these three pipeline, motorization of block valves for remote operation on the remaining pipelines is intended, depending on the success of these implementations, on historical records of failure and appropriate ranking. (author)

  14. Analysis and Disposal of Problem Concerning Regulation System Occurred High Value of Pressure Control Regulating Valve Servo%汽轮机调节系统二次脉动油压异常分析

    Institute of Scientific and Technical Information of China (English)

    刘军龙; 黄潜; 张福海; 胡冬清; 姜剑峰; 郭光宗

    2014-01-01

    针对田湾核电站汽轮机夏季运行工况时出现调节系统二次脉动油压高且波动问题,采用两台机组汽轮机调节系统静态试验曲线以及热力系统参数对比分析的方法,阐述了循环冷却水温度、二次脉动油压拐点、调节阀空行程对二次脉动油压的影响。根据研究结果,通过提高二次脉动油压拐点及减小高压调节阀油动机空行程的纠正措施,有效解决了此问题,提高了调节系统的稳定性。对机组的运行和维修具有一定的借鉴意义。%Based on the problem concerning regulation system occurred high value and fluctuation of pressure-control regulating valve servo in operation condition of spring for steam turbine in Tianwan Nuclear Power Station, method of comparative analysis are adopted for static test curve of regulation system and parameter of thermal system of two units. It is expatiated that the temperature of circulation cooling water, the knee of pressure-control regulating valve servo and idle stroke of regulation valve servo influenced on pressure-control regulating valve servo. According to result of study, corrective measures are taken to increase the knee of pressure control regulating valve servo and to decrease the idle stroke of regulation valve, which is effective to solve the problem and improve the stability of regulation system. It will be good reference for unit’s operation and maintenance.

  15. Statins for aortic valve stenosis

    Directory of Open Access Journals (Sweden)

    Luciana Thiago

    Full Text Available ABSTRACT BACKGROUND: Aortic valve stenosis is the most common type of valvular heart disease in the USA and Europe. Aortic valve stenosis is considered similar to atherosclerotic disease. Some studies have evaluated statins for aortic valve stenosis. OBJECTIVES: To evaluate the effectiveness and safety of statins in aortic valve stenosis. METHODS: Search methods: We searched the Cochrane Central Register of Controlled Trials (CENTRAL, MEDLINE, Embase, LILACS - IBECS, Web of Science and CINAHL Plus. These databases were searched from their inception to 24 November 2015. We also searched trials in registers for ongoing trials. We used no language restrictions. Selection criteria: Randomized controlled clinical trials (RCTs comparing statins alone or in association with other systemic drugs to reduce cholesterol levels versus placebo or usual care. Data collection and analysis: Primary outcomes were severity of aortic valve stenosis (evaluated by echocardiographic criteria: mean pressure gradient, valve area and aortic jet velocity, freedom from valve replacement and death from cardiovascular cause. Secondary outcomes were hospitalization for any reason, overall mortality, adverse events and patient quality of life. Two review authors independently selected trials for inclusion, extracted data and assessed the risk of bias. The GRADE methodology was employed to assess the quality of result findings and the GRADE profiler (GRADEPRO was used to import data from Review Manager 5.3 to create a 'Summary of findings' table. MAIN RESULTS: We included four RCTs with 2360 participants comparing statins (1185 participants with placebo (1175 participants. We found low-quality evidence for our primary outcome of severity of aortic valve stenosis, evaluated by mean pressure gradient (mean difference (MD -0.54, 95% confidence interval (CI -1.88 to 0.80; participants = 1935; studies = 2, valve area (MD -0.07, 95% CI -0.28 to 0.14; participants = 127; studies = 2

  16. 多通阀控制器与计量控制器之间的关联控制系统%Interconnected Control Systems of Multiway Valve Controller and Measuring Controllers

    Institute of Scientific and Technical Information of China (English)

    文恒

    2012-01-01

    分析新疆油田计量站自动化控制系统中多通阀PLC与计量PLC/RTU之间的控制方式,提出一套基于通信的软逻辑解决方案,实现计量站多通阀切换和单井产量的连续计量。介绍硬连接和软逻辑实现的方式及优缺点。%The control modes between multiway PLC and measuring PLC/RTU of automatic control system in Xinjiang oilfield metering station are analyzed. A soft logic solution based on communication is proposed and the multiway valve switch and continuous metering of output per well are implemented. The hardware connection, hard and soft logic implementation, advantages and disadvantages are introduced.

  17. 46 CFR 154.532 - Valves: Cargo tank MARVS greater than 69 kPa gauge (10 psig).

    Science.gov (United States)

    2010-10-01

    ... practical, a: (1) Stop valve capable of local manual operation; and (2) A remotely controlled quick-closing... section. (c) One valve may be substituted for the manual controlled stop valve and the remotely controlled... 46 Shipping 5 2010-10-01 2010-10-01 false Valves: Cargo tank MARVS greater than 69 kPa gauge (10...

  18. 电动可调式动态流量平衡阀和末端电动调节定压差阀结合的水力平衡与控制策略%Hydraulic balance and control strategy of combination control system of electric adjustable dynamic balancing valve and terminal electric constant pressure valve

    Institute of Scientific and Technical Information of China (English)

    孙晋飞; 郭健翔; 沈聪; 李林

    2012-01-01

    分析了集中空调系统水力失调的原因和解决措施,通过比较末端恒压差控制系统和应用电动可调式动态流量平衡阀的控制系统的控制原理以及变流量条件下的能耗高低,研究了这两个控制系统对管网中调节阀流量特性曲线的影响,具体分析了设备效率对系统性能的影响.%Examines the cause and solutions of hydraulic disorder of central air conditioning systems. According to the comparison of control principle and energy consumption under variable flow rate condition between the end constant pressure difference control system and the control system with electric adjustable dynamic balancing valve, studies the influence of the two control systems on the flow characteristic curve of the electric control valve, and analyses the influence of equipment efficiency on the performance of the system in detail.

  19. FTO Is Associated with Aortic Valve Stenosis in a Gender Specific Manner of Heterozygote Advantage: A Population-Based Case-Control Study.

    Directory of Open Access Journals (Sweden)

    Cindy Thron

    Full Text Available Single nucleotide polymorphisms (SNPs within the Fat mass and obesity associated (FTO gene have been linked with increased body weight. However, the data on an association of FTO with cardiovascular diseases remains conflicting. Therefore, we ascertained whether FTO is associated with aortic valve stenosis (AVS, one of the most frequent cardiovascular diseases in the Western world.In this population-based case-control study the FTO SNP rs9939609 was analyzed in 300 German patients with AVS and 429 German controls of the KORA survey S4, representing a random population. Blood samples were collected prior to aortic valve replacement in AVS cases and FTO rs9939609 was genotyped via ARMS-PCR. Genotype frequencies differed significantly between AVS cases and KORA controls (p = 0.004. Separate gender-analyses uncovered an association of FTO with AVS exclusively in males; homozygote carriers for the risk-allele (A had a higher risk to develop AVS (p = 0.017, odds ratio (OR 1.727; 95% confidence interval (CI 1.087-2.747, recessive model, whereas heterozygote carriers for the risk-allele showed a lower risk (p = 0.002, OR 0.565, 95% CI 0.384-0.828, overdominant model. After adjustment for multiple co-variables, the odds ratios of heterozygotes remained significant for an association with AVS (p = 0.008, OR 0.565, 95% CI 0.369-0.861.This study revealed an association of FTO rs9939609 with AVS. Furthermore, this association was restricted to men, with heterozygotes having a significantly lower chance to develop AVS. Lastly, the association between FTO and AVS was independent of BMI and other variables such as diabetes mellitus.

  20. Valve exploiting the principle of a side channel turbine

    Directory of Open Access Journals (Sweden)

    Jandourek Pavel

    2017-01-01

    Full Text Available The article deals with a side channel turbine, which can be used as a suitable substitute for a pressure reducing valve. Reducing valves are a source of hydraulic losses. The aim is to replace them by a side channel turbine. With that in mind, hydraulic losses can be replaced by a production of electrical energy at comparable characteristics of the valve and the turbine. The basis for the design is the loss characteristics of the valve. Thereby creating a kind of turbine valve with speed-controlled flow in dependence of runner revolution.

  1. The design and application of ballast valve groups remote-control system for Ro-Ro ship%滚装船压载阀组遥控系统的设计与应用

    Institute of Scientific and Technical Information of China (English)

    万会雄; 明仁雄; 章琅浩

    2001-01-01

    了实现对滚装船压载舱压载阀的开闭实行有效的控 制,文章介绍了压载阀组遥控系统的组成、工作原理以及该系统的设计特点与应用。%To realize the effective control to starting an d shutting of ballast valve groups,this paper introduces the composition,working principle,designing features and application of ballast valve groups remote-co ntrol system for Ro-Ro ship.

  2. Thermostatic Radiator Valve Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Dentz, J. [Advanced Residential Integrated Energy Solutions Collaborative (ARIES), New York, NY (United States); Ansanelli, E. [Advanced Residential Integrated Energy Solutions Collaborative (ARIES), New York, NY (United States)

    2015-01-01

    A large stock of multifamily buildings in the Northeast and Midwest are heated by steam distribution systems. Losses from these systems are typically high and a significant number of apartments are overheated much of the time. Thermostatically controlled radiator valves (TRVs) are one potential strategy to combat this problem, but have not been widely accepted by the residential retrofit market. In this project, the ARIES team sought to better understand the current usage of TRVs by key market players in steam and hot water heating and to conduct limited experiments on the effectiveness of new and old TRVs as a means of controlling space temperatures and reducing heating fuel consumption. The project included a survey of industry professionals, a field experiment comparing old and new TRVs, and cost-benefit modeling analysis using BEopt™ (Building Energy Optimization software).

  3. Pressure activated stability-bypass-control valves to increase the stable airflow range of a Mach 2.5 inlet with 40 percent internal contraction

    Science.gov (United States)

    Mitchell, G. A.; Sanders, B. W.

    1974-01-01

    The throat of a Mach 2.5 inlet with a coldpipe termination was fitted with a stability-bypass system. The inlet stable airflow range provided by various stability-bypass entrance configurations in alternate combination with several stability-bypass exit controls was determined for both steady-state conditions and internal transient pulses. Transient results were also obtained for the inlet with a choke point at the diffuser exit. Instart angles of attack were determined for the various stability-bypass entrance configurations. The response of the inlet-coldpipe system to internal and external oscillating disturbances was determined. Poppet valves at the stability-bypass exit provided an inlet stable airflow range of 28 percent or greater at all static and transient conditions.

  4. Design factors for “linear” ball valve: theoretical and experimental studies

    OpenAIRE

    Thananchai Leephakpreeda

    2005-01-01

    Generic non-linear flow characteristics of the conventional ball valve limit the applications of flow modulation in fluid processes. This work presents the flow characteristics of fluid flowing through the conventional and modified ball valves for feasibility of a “linear” ball valve. Theoretical studies are discussed for determining explicit and implicit factors on the valve coefficient, which modulates the flow rate of fluid when the ball valve is operated in flow control processes. In expe...

  5. DESIGN THEORY FOR G-π BRIDGERELIEF VALVE WITH ZERO OVERRIDE

    Institute of Scientific and Technical Information of China (English)

    Hu Yanping; Huang Zhichu; Liu Deshun; Mao Zhengyu

    2004-01-01

    A new construction of the relief valve is presented with pilot G-( bridg hydraulic resistances network. The design theory of G-( bridge relief valve is studied and the formulas for designing the relief valve with zero static pressure override are obtained. The static performances of the relief valve are experimentally investigated. The theoretical and experimental results show that the static pressure override of the developed relief valve can be zero, i.e. when the overflow increases the control pressure is kept constant.

  6. Aortic or Mitral Valve Replacement With the Biocor and Biocor Supra

    Science.gov (United States)

    2016-03-09

    Aortic Valve Insufficiency; Aortic Valve Regurgitation; Aortic Valve Stenosis; Aortic Valve Incompetence; Mitral Valve Insufficiency; Mitral Valve Regurgitation; Mitral Valve Stenosis; Mitral Valve Incompetence

  7. Reliability Evaluation of Concentric Butterfly Valve Using Statistical Hypothesis Test

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Mu Seong; Choi, Jong Sik; Choi, Byung Oh; Kim, Do Sik [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2015-12-15

    A butterfly valve is a type of flow-control device typically used to regulate a fluid flow. This paper presents an estimation of the shape parameter of the Weibull distribution, characteristic life, and B10 life for a concentric butterfly valve based on a statistical analysis of the reliability test data taken before and after the valve improvement. The difference in the shape and scale parameters between the existing and improved valves is reviewed using a statistical hypothesis test. The test results indicate that the shape parameter of the improved valve is similar to that of the existing valve, and that the scale parameter of the improved valve is found to have increased. These analysis results are particularly useful for a reliability qualification test and the determination of the service life cycles.

  8. Numerical Analysis for Structural Safety Evaluation of Butterfly Valves

    Science.gov (United States)

    Shin, Myung-Seob; Yoon, Joon-Yong; Park, Han-Yung

    2010-06-01

    Butterfly valves are widely used in current industry to control the fluid flow. They are used for both on-off and throttling applications involving large flows at relatively low operating pressure especially in large size pipelines. For the industrial application of butterfly valves, it must be ensured that the valve could be used safety under the fatigue life and the deformations produced by the pressure of the fluid. In this study, we carried out the structure analysis of the body and the valve disc of the butterfly valve and the numerical simulation was performed by using ANSYS v11.0. The reliability of valve is evaluated under the investigation of the deformation, the leak test and the durability of the valve.

  9. Remote manual operator for space station intermodule ventilation valve

    Science.gov (United States)

    Guyaux, James R.

    1996-01-01

    The Remote Manual Operator (RMO) is a mechanism used for manual operation of the Space Station Intermodule Ventilation (IMV) valve and for visual indication of valve position. The IMV is a butterfly-type valve, located in the ventilation or air circulation ducts of the Space Station, and is used to interconnect or isolate the various compartments. The IMV valve is normally operated by an electric motor-driven actuator under computer or astronaut control, but it can also be operated manually with the RMO. The IMV valve RMO consists of a handle with a deployment linkage, a gear-driven flexible shaft, and a linkage to disengage the electric motor actuator during manual operation. It also provides visual indication of valve position. The IMV valve RMO is currently being prepared for qualification testing.

  10. JenaValve.

    Science.gov (United States)

    Treede, Hendrik; Rastan, Ardawan; Ferrari, Markus; Ensminger, Stephan; Figulla, Hans-Reiner; Mohr, Friedrich-Wilhelm

    2012-09-01

    The JenaValve is a next-generation TAVI device which consists of a well-proven porcine root valve mounted on a low-profile nitinol stent. Feeler guided positioning and clip fixation on the diseased leaflets allow for anatomically correct implantation of the device without rapid pacing. Safety and efficacy of transapical aortic valve implantation using the JenaValve were evaluated in a multicentre prospective study that showed good short and midterm results. The valve was CE-mark released in Europe in September 2011. A post-market registry ensures on-going and prospective data collection in "real-world" patients. The transfemoral JenaValve delivery system will be evaluated in a first-in-man study in the near future.

  11. Cryogenic Cam Butterfly Valve

    Science.gov (United States)

    McCormack, Kenneth J. (Inventor)

    2016-01-01

    A cryogenic cam butterfly valve has a body that includes an axially extending fluid conduit formed there through. A disc lug is connected to a back side of a valve disc and has a circular bore that receives and is larger than a cam of a cam shaft. The valve disc is rotatable for a quarter turn within the body about a lug axis that is offset from the shaft axis. Actuating the cam shaft in the closing rotational direction first causes the camming side of the cam of the cam shaft to rotate the disc lug and the valve disc a quarter turn from the open position to the closed position. Further actuating causes the camming side of the cam shaft to translate the valve disc into sealed contact with the valve seat. Opening rotational direction of the cam shaft reverses these motions.

  12. Fracturing mechanics before valve-in-valve therapy of small aortic bioprosthetic heart valves

    DEFF Research Database (Denmark)

    Johansen, Peter; Engholt, Henrik; Tang, Mariann

    2017-01-01

    AIMS: Patients with degraded bioprosthetic heart valves (BHV) who are not candidates for valve replacement may benefit from transcatheter valve-in-valve (VIV) therapy. However, at smaller sized surgical BHV the resultant orifice may become too narrow. To overcome this, the valve frame can be frac...

  13. A Research on Closed Valve Cover Production Process Quality Control%常闭阀罩生产过程质量控制研究

    Institute of Scientific and Technical Information of China (English)

    赵会珍; 赵虎

    2014-01-01

    Observing the quality problems in a closed valve cover enterprise , quality control theory and methods are used to improve the quality of closed valve cover .First, a praetor diagram method is used to analyze the product quality problems;and then , using measurement system analysis , process capability a-nalysis is made to find the key factors;using a fishbone diagram , a linear regression analysis is made to de-sign the improvement scheme;using Minitab software , data is analyzed .Finally , improved improved im-provedtithe project is successfully implemented , whose result shows that failure rate is reduced largely , and the process capability improved from 0.54 to 1.22.%为了解决某公司常闭阀罩生产过程中质量不稳定、生产过程能力低等问题,将质量管理方法应用于常闭阀罩生产的管理过程。利用测量系统分析、过程能力分析、一元线性回归分析等方法进行产品质量的分析,并结合Minit-ab软件里面的功能模块,精确计算过程能力指数,生成控制图,根据判定准则,给出判定结论。企业应用实例表明,该公司在实施了质量控制后,过程能力提高,废品率降低,有效地提高了产品质量。

  14. Design Optimisation and Conrol of a Pilot Operated Seat Valve

    DEFF Research Database (Denmark)

    Nielsen, Brian; Andersen, Torben Ole; Hansen, Michael Rygaard

    2004-01-01

    The paper gives an approach for optimisation of the bandwidth of a pilot operated seat valve for mobile applications. Physical dimensions as well as parameters of the implemented control loop are optimised simultaneously. The frequency response of the valve varies as a function of the pressure drop...... across the valve, and it is found to be necessary to scale the controller parameters in the optimised design as a function of pressure drop....

  15. Mitral valve prolapse.

    Science.gov (United States)

    Gould, L; Gopalaswamy, C

    1984-05-01

    Mitral valve prolapse is a very common condition. It occurs in 4-5% of the population. It may be idiopathic or associated with a number of other conditions. Myxomatous degeneration is the underlying mechanism of mitral valve prolapse. Most patients with mitral valve prolapse have no symptoms. When symptoms do occur, palpitations, chest pain and dyspnea are the major complaints. The midsystolic click occasionally followed by the late systolic murmur are the typical physical findings. The echocardiogram plays a big role in the diagnosis of mitral valve prolapse. The beta blockers are used in the treatment of the symptomatic patient.

  16. Biological heart valves.

    Science.gov (United States)

    Ciubotaru, Anatol; Cebotari, Serghei; Tudorache, Igor; Beckmann, Erik; Hilfiker, Andres; Haverich, Axel

    2013-10-01

    Cardiac valvular pathologies are often caused by rheumatic fever in young adults, atherosclerosis in elderly patients, or by congenital malformation of the heart in children, in effect affecting almost all population ages. Almost 300,000 heart valve operations are performed worldwide annually. Tissue valve prostheses have certain advantages over mechanical valves such as biocompatibility, more physiological hemodynamics, and no need for life-long systemic anticoagulation. However, the major disadvantage of biological valves is related to their durability. Nevertheless, during the last decade, the number of patients undergoing biological, rather than mechanical, valve replacement has increased from half to more than three-quarters for biological implants. Continuous improvement in valve fabrication includes development of new models and shapes, novel methods of tissue treatment, and preservation and implantation techniques. These efforts are focused not only on the improvement of morbidity and mortality of the patients but also on the improvement of their quality of life. Heart valve tissue engineering aims to provide durable, "autologous" valve prostheses. These valves demonstrate adaptive growth, which may avoid the need of repeated operations in growing patients.

  17. 2D DIGITAL SIMPLIFIED FLOW VALVE

    Institute of Scientific and Technical Information of China (English)

    Ruan Jian; Li Sheng; Pei Xiang; Burton R; Ukrainetz P; Bitner D

    2004-01-01

    The 2D digital simplified flow valve is composed of a pilot-operated valve designed with both rotary and linear motions of a single spool,and a stepper motor under continual control.How the structural parameters affect the static and dynamic characteristics of the valve is first clarified and a criterion for stability is presented.Experiments are designed to test the performance of the valve.It is necessary to establish a balance between the static and dynamic characteristics in deciding the structural parameters.Nevertheless,it is possible to maintain the dynamic response at a fairly high level,while keeping the leakage of the pilot stage at an acceptable level.One of the features of the digital valve is stage control.In stage control the nonlinearities,such as electromagnetic saturation and hysteresis,are greatly reduced.To a large extent the dynamic response of the valve is decided by the executing cycle of the control algorithm.

  18. Absence of venous valves in mice lacking Connexin37.

    Science.gov (United States)

    Munger, Stephanie J; Kanady, John D; Simon, Alexander M

    2013-01-15

    Venous valves play a crucial role in blood circulation, promoting the one-way movement of blood from superficial and deep veins towards the heart. By preventing retrograde flow, venous valves spare capillaries and venules from being subjected to damaging elevations in pressure, especially during skeletal muscle contraction. Pathologically, valvular incompetence or absence of valves are common features of venous disorders such as chronic venous insufficiency and varicose veins. The underlying causes of these conditions are not well understood, but congenital venous valve aplasia or agenesis may play a role in some cases. Despite progress in the study of cardiac and lymphatic valve morphogenesis, the molecular mechanisms controlling the development and maintenance of venous valves remain poorly understood. Here, we show that in valved veins of the mouse, three gap junction proteins (Connexins, Cxs), Cx37, Cx43, and Cx47, are expressed exclusively in the valves in a highly polarized fashion, with Cx43 on the upstream side of the valve leaflet and Cx37 on the downstream side. Surprisingly, Cx43 expression is strongly induced in the non-valve venous endothelium in superficial veins following wounding of the overlying skin. Moreover, we show that in Cx37-deficient mice, venous valves are entirely absent. Thus, Cx37, a protein involved in cell-cell communication, is one of only a few proteins identified so far as critical for the development or maintenance of venous valves. Because Cxs are necessary for the development of valves in lymphatic vessels as well, our results support the notion of common molecular pathways controlling valve development in veins and lymphatic vessels.

  19. Heart Valve Biomechanics and Underlying Mechanobiology

    Science.gov (United States)

    Ayoub, Salma; Ferrari, Giovanni; Gorman, Robert C.; Gorman, Joseph H.; Schoen, Frederick J.; Sacks, Michael S.

    2017-01-01

    Heart valves control unidirectional blood flow within the heart during the cardiac cycle. They have a remarkable ability to withstand the demanding mechanical environment of the heart, achieving lifetime durability by processes involving the ongoing remodeling of the extracellular matrix. The focus of this review is on heart valve functional physiology, with insights into the link between disease-induced alterations in valve geometry, tissue stress, and the subsequent cell mechanobiological responses and tissue remodeling. We begin with an overview of the fundamentals of heart valve physiology and the characteristics and functions of valve interstitial cells (VICs). We then provide an overview of current experimental and computational approaches that connect VIC mechanobiological response to organ- and tissue-level deformations and improve our understanding of the underlying functional physiology of heart valves. We conclude with a summary of future trends and offer an outlook for the future of heart valve mechanobiology, specifically, multiscale modeling approaches, and the potential directions and possible challenges of research development. PMID:27783858

  20. Optimization of Valve Disc Using Orthogonal Array and Kriging Model

    Science.gov (United States)

    Song, Xueguan; Wang, Lin; Kang, Jungho; Kim, Seung Gyu; Jo, Young Jik; Park, Youngchul

    2008-10-01

    A butterfly valve is a type of flow control device, typically used to regulate a fluid flowing. Currently, FEA is often used to predict the safety in the design of valve disc. Also, the study about the affection of butterfly valve's disc to the valve flow characteristics by using CFD has been done by many researchers. Along with the development of computer technique, design and analysis of computer experiments has becoming more and more important in engineering design and optimization. Hereinto Kriging model is one popular analysis approach for the purpose of creating a cheap "meta-model" as a surrogate to a computationally expensive simulation model. In this paper, the numerical analysis considered the strength, pressure loss coefficient and weight of valve disc simultaneously is investigated to improve the shape of a traditional butterfly valve disc. Firstly, an initial model of butterfly valve is made to evaluate the performance of the valve disc by using CFD and FEM. Then several experiments with different variables combination of the valve disc are conducted by mean of orthogonal array. Finally, the Kriging model is used to find the optimum variables combination of valve disc based on the result of computer experiments. In addition, the optimum result is verified by FEA and CFD simulation again. The result shows that compared with traditional computer experiments, optimization by using Kriging model can improve the weight of the valve disc very effectively in a short time.

  1. Randomised controlled trial of thermostatic mixer valves in reducing bath hot tap water temperature in families with young children in social housing: A protocol

    Directory of Open Access Journals (Sweden)

    Phillips Ceri

    2008-03-01

    Full Text Available Abstract Background Each year in the UK 2000 children attend emergency departments and 500 are admitted to hospital following a bath water scald. The long term effects can include disability, disfigurement or psychological harm and repeated skin grafts may be required as the child grows. The costs of treating a severe scald are estimated at 250,000 GBP. Children living in the most deprived wards are at greatest risk of thermal injuries; hospital admission rates are three times that for children living in the least deprived wards. Domestic hot water, which is usually stored at around 60 degrees Celsius, can result in a second-degree burn after 3 seconds and a third-degree burn after 5 seconds. Educational strategies to encourage testing of tap water temperature and reduction of hot water thermostat settings have largely proved unsuccessful. Legislation in the USA mandating pre-setting hot water heater thermostats at 49 degrees Celsius was effective in reducing scald injuries, suggesting passive measures may have a greater impact. Thermostatic mixer valves (TMVs, recently developed for the domestic market, fitted across the hot and cold water supply pipes of the bath, allow delivery of water set at a fixed temperature from the hot bath tap. These valves therefore offer the potential to reduce scald injuries. Design/Methods A pragmatic, randomised controlled trial to assess the effectiveness of TMVs in reducing bath hot tap water temperatures in the homes of families with young children in rented social housing. Two parallel arms include an intervention group and a control group where the intervention will be deferred. The intervention will consist of fitting a TMV (set at 44 degrees Celsius by a qualified plumber and provision of educational materials. The control arm will not receive a TMV or the educational materials for the study duration but will be offered the intervention after collection of follow-up data 12 months post randomisation. The

  2. A piezoelectrically actuated ball valve

    Science.gov (United States)

    Erwin, L. R.; Schwartz, H. W.; Teitelbaum, B. R.

    1972-01-01

    Bimorph strip composed of two layers of poled piezoelectric ceramic material closes and opens valve. Strip performs like capacitator, allowing initial inrush of current when valve is energized and then only small leakage current flows as valve remains energized.

  3. Analysis on Performance and Fault Relation for Automatic Pressure Keeping Weight Type Hydraulic Control Butterfly Valve%自动保压重锤式液控蝶阀性能与故障关系分析

    Institute of Scientific and Technical Information of China (English)

    陈培兴; 狄翠霞

    2012-01-01

    自动保压重锤式液控蝶阀采用二阶段关闭,与普通阀门有所不同.简单介绍蝶阀可能出现的主要故障及其原因,通过具体实例说明如何根据二阶段液控蝶阀的最主要性能指标即开阀时间、快关时间、慢关时间的变化及相互之间的关系排除故障.%Because two-stage closing is adopted in automatic pressure keeping weight type hydraulic control butterfly valve, it is different from common valves. The main faults and causes of the butterfly valve were introduced. Through an example, it was shown that how to remove faults according to the main performance indexes changes of the hydraulic controlled butterfly valve and their mutual relations.

  4. A novel implantable glaucoma valve using ferrofluid.

    Directory of Open Access Journals (Sweden)

    Eleftherios I Paschalis

    Full Text Available PURPOSE: To present a novel design of an implantable glaucoma valve based on ferrofluidic nanoparticles and to compare it with a well-established FDA approved valve. SETTING: Massachusetts Eye & Ear Infirmary, Boston, USA. METHODS: A glaucoma valve was designed using soft lithography techniques utilizing a water-immiscible magnetic fluid (ferrofluid as a pressure-sensitive barrier to aqueous flow. Two rare earth micro magnets were used to calibrate the opening and closing pressure. In-vitro flow measurements were performed to characterize the valve and to compare it to Ahmed™ glaucoma valve. The reliability and predictability of the new valve was verified by pressure/flow measurements over a period of three months and X-ray diffraction (XRD analysis over a period of eight weeks. In vivo assessment was performed in three rabbits. RESULTS: In the in vitro experiments, the opening and closing pressures of the valve were 10 and 7 mmHg, respectively. The measured flow/pressure response was linearly proportional and reproducible over a period of three months (1.8 µl/min at 12 mmHg; 4.3 µl/min at 16 mmHg; 7.6 µl/min at 21 mmHg. X-ray diffraction analysis did not show oxidization of the ferrofluid when exposed to water or air. Preliminary in vivo results suggest that the valve is biocompatible and can control the intraocular pressure in rabbits. CONCLUSIONS: The proposed valve utilizes ferrofluid as passive, tunable constriction element to provide highly predictable opening and closing pressures while maintaining ocular tone. The ferrofluid maintained its magnetic properties in the aqueous environment and provided linear flow to pressure response. Our in-vitro tests showed reliable and reproducible results over a study period of three months. Preliminary in-vivo results were very promising and currently more thorough investigation of this device is underway.

  5. Research on Pneumatic Position Control Using on/off Valves Based on PWM%高速开关阀的气缸定位控制

    Institute of Scientific and Technical Information of China (English)

    胡杰; 许昌

    2011-01-01

    首先分析了基于PWM高速开关阀的气缸定位控制系统的工作原理,在此基础上建立阀控缸定位系统的数学模型.应用脉宽调制方式以及常规PID控制算法和模糊PID控制算法,在MATLAB/SIMULINK上对基于高速开关阀的气缸定位系统进行了仿真.仿真结果表明,用模糊PID控制算法控制阀控缸定位系统,可以实现更快速、更精确的气动执行器位置伺服控制.%Firstly,this paper analyses the working principle of cylinder postton controlling system based on PWM with on/off solenoid valves and then establishs the pneumatic system model. Moreover, using conventional General PID and Fuzzy -PID control algorithm, the established model is simulated by MATLAB/SIMULINK. The results show that controlling the system with Fuzzy - PID algorithm can achieve a more fast, more precise pneumatic actuator positon.

  6. Controls of evaporative irrigation return flows in comparison to seawater intrusion in coastal karstic aquifers in northern Sri Lanka: evidence from solutes and stable isotopes

    Science.gov (United States)

    Chandrajith, Rohana; Diyabalanage, Saranga; Premathilake, Mahinda; Hanke, Christian; van Geldern, Robert; Barth, Johannes A. C.

    2016-04-01

    Groundwater in Miocene karstic aquifers in the Jaffna Peninsula of Sri Lanka is an important resource since no other fresh water sources are available in the region. The subsurface is characterized by highly productive limestone aquifers that are used for drinking and agriculture purposes. A comprehensive hydrogeochemical study was carried out to reveal the processes affecting the groundwater quality in this region. Major and trace element composition and environmental isotope ratios of oxygen and hydrogen (δ18OH2O and δ2HH2O) were determined in 35 groundwater samples for this investigation. The ion abundance of groundwater in the region was characterized by an anion sequence order with HCO3¯ >Cl¯ >SO4¯ >NO3¯ . For cations, average Na++K+ contents in groundwater exceeded those of Ca2++Mg2+ in most cases. Ionic relationships of major solutes indicated open system calcite dissolution while seawater intrusions are also evident but only close to the coast. The solute contents are enriched by agricultural irrigation returns and associated evaporation. This was confirmed by the stable isotope composition of groundwater that deviated from the local meteoric water line (LMWL) and formed its own regression line denoted as the local evaporation line (LEL). The latter can be described by δ2HH2O=5.8 ×δ18OH2O - 2.9. Increased contents of nitrate (up to 26 mg/L), sulfate (up to 430 mg/L) and fluoride (up to 1.5 mg/L) provided evidences for anthropogenic inputs of solutes, most likely from agriculture activities. Among trace elements Ba, Sr, As and Se levels in the Jaffna groundwater were higher compared to that of the dry zone metamorphic aquifers in Sri Lanka. Solute geochemistry and stable isotope evidences from the region indicates that groundwater in the area is mainly derived from local modern precipitation but modified heavily by progressive evaporative concentration rather than seawater intrusion. The currently most imminent vulnerability of groundwater in the

  7. Mitral valve surgery - open

    Science.gov (United States)

    ... Saunders; 2012:chap 61. Otto CM, Bonow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ... Editorial team. Related MedlinePlus Health Topics Heart Surgery Heart Valve Diseases Mitral Valve Prolapse Browse the Encyclopedia A.D. ...

  8. Blocked Urethral Valves

    Science.gov (United States)

    ... Blocked Urethral Valves Health Issues Listen Español Text Size Email Print Share Blocked Urethral Valves Page Content Article Body Urine leaves the bladder through a tube called the urethra, which in boys passes through the penis. Rarely, small membranes form across the urethra in ...

  9. The prognosis of infective endocarditis treated with biological valves versus mechanical valves: A meta-analysis.

    Science.gov (United States)

    Tao, Ende; Wan, Li; Wang, WenJun; Luo, YunLong; Zeng, JinFu; Wu, Xia

    2017-01-01

    Surgery remains the primary form of treatment for infective endocarditis (IE). However, it is not clear what type of prosthetic valve provides a better prognosis. We conducted a meta-analysis to compare the prognosis of infective endocarditis treated with biological valves to cases treated with mechanical valves. Pubmed, Embase and Cochrane databases were searched from January 1960 to November 2016.Randomized controlled trials, retrospective cohorts and prospective studies comparing outcomes between biological valve and mechanical valve management for infective endocarditis were analyzed. The Newcastle-Ottawa Scale(NOS) was used to evaluate the quality of the literature and extracted data, and Stata 12.0 software was used for the meta-analysis. A total of 11 publications were included; 10,754 cases were selected, involving 6776 cases of biological valves and 3,978 cases of mechanical valves. The all-cause mortality risk of the biological valve group was higher than that of the mechanical valve group (HR = 1.22, 95% CI 1.03 to 1.44, P = 0.023), as was early mortality (RR = 1.21, 95% CI 1.02 to 1.43, P = 0.033). The recurrence of endocarditis (HR = 1.75, 95% CI 1.26 to 2.42, P = 0.001), as well as the risk of reoperation (HR = 1.79, 95% CI 1.15 to 2.80, P = 0.010) were more likely to occur in the biological valve group. The incidence of postoperative embolism was less in the biological valve group than in the mechanical valve group, but this difference was not statistically significant (RR = 0.90, 95% CI 0.76 to 1.07, P = 0.245). For patients with prosthetic valve endocarditis (PVE), there was no significant difference in survival rates between the biological valve group and the mechanical valve group (HR = 0.91, 95% CI 0.68 to 1.21, P = 0.520). The results of our meta-analysis suggest that mechanical valves can provide a significantly better prognosis in patients with infective endocarditis. There were significant differences in the clinical features of patients

  10. Contamination avoidance devices for poppettype shutoff valves

    Science.gov (United States)

    Endicott, D. L.

    1973-01-01

    The determination of the cycle life is reported of the scal closure of a typical poppet-type shutoff valve in an uncontaminated GH2 environment and then compared this component performance with simulated operation with GN2 and LN2 containing controlled amounts of AL2O3 contaminant particles. The original valve design was tested for contamination damage tolerance characteristics under full-flow and cyclic-operating conditions, redesigned to improve the damage tolerance to contaminants, and then retested. The redesigned valve was found to have acceptable tolerance characteristics under all full-flow conditions and cyclic operation with small (25-75 microns) particulate contamination. The tolerance characteristics of the valve under cyclic conditions with large (75-250 microns) particulate contamination was improved but was not found to be completely satisfactory.

  11. Bioprinting a cardiac valve.

    Science.gov (United States)

    Jana, Soumen; Lerman, Amir

    2015-12-01

    Heart valve tissue engineering could be a possible solution for the limitations of mechanical and biological prostheses, which are commonly used for heart valve replacement. In tissue engineering, cells are seeded into a 3-dimensional platform, termed the scaffold, to make the engineered tissue construct. However, mimicking the mechanical and spatial heterogeneity of a heart valve structure in a fabricated scaffold with uniform cell distribution is daunting when approached conventionally. Bioprinting is an emerging technique that can produce biological products containing matrix and cells, together or separately with morphological, structural and mechanical diversity. This advance increases the possibility of fabricating the structure of a heart valve in vitro and using it as a functional tissue construct for implantation. This review describes the use of bioprinting technology in heart valve tissue engineering.

  12. Anticoagulation for Prosthetic Valves

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Kaneko

    2013-01-01

    Full Text Available Implantation of prosthetic valve requires consideration for anticoagulation. The current guideline recommends warfarin on all mechanical valves. Dabigatran is the new generation anticoagulation medication which is taken orally and does not require frequent monitoring. This drug is approved for treatment for atrial fibrillation and venous thromboembolism, but the latest large trial showed that this drug increases adverse events when used for mechanical valve anticoagulation. On-X valve is the new generation mechanical valve which is considered to require less anticoagulation due to its flow dynamics. The latest study showed that lower anticoagulation level lowers the incidence of bleeding, while the risk of thromboembolism and thrombosis remained the same. Anticoagulation poses dilemma in cases such as pregnancy and major bleeding event. During pregnancy, warfarin can be continued throughout pregnancy and switched to heparin derivative during 6–12 weeks and >36 weeks of gestation. Warfarin can be safely started after 1-2 weeks of discontinuation following major bleeding episode.

  13. Simultaneous Individually Controlled Upper and Lower Body Perfusion for Valve-Sparing Root and Total Aortic Arch Replacement: A Case Study

    Science.gov (United States)

    Fernandes, Philip; Mayer, Rick; Adams, Corey; Chu, Michael W.A.

    2011-01-01

    Abstract: Optimal perfusion strategies for extensive aortic resection in patients with mega-aortic syndromes include: tailored myocardial preservation, antegrade cerebral perfusion, controlled hypothermia and selective organ perfusion. Typically, the aortic arch resection and elephant trunk procedure are performed under hypothermic circulatory arrest with myocardial and cerebral protection. However, mesenteric and systemic ischemia occur during circulatory arrest and commonly rely upon deep hypothermia alone for metabolic protection. We hypothesized that simultaneously controlled mesenteric and systemic perfusion can attenuate some of the metabolic debt accrued during circulatory arrest, which may help improve perioperative outcomes. The perfusion strategy consisted of delivering a 1 to 3 liter per minute flow at 25°C to the head/upper body via right axillary graft and simultaneous perfusion to the lower body/mesenteric organs of 1 to 3 liters per minute at 30°C via a right femoral arterial graft. We describe our technique of simultaneous mesenteric, systemic, cerebral and myocardial perfusion, and protection utilized for a young male patient with Marfan’s syndrome, while undergoing a valve sparing root replacement, total arch replacement and elephant trunk reconstruction. This perfusion technique allowed us to deliver differential flow rates and temperatures to the upper and lower body (cold head/warm lower body perfusion) to minimize ischemic debt and quickly reverse metabolic derangements. PMID:22416605

  14. Lymphangiogenesis is increased in heart valve endocarditis.

    Science.gov (United States)

    Niinimäki, Eetu; Mennander, Ari A; Paavonen, Timo; Kholová, Ivana

    2016-09-15

    Inflammation-associated lymphangiogenesis (IAL) has been identified as part of several acute and chronic inflammation. Sparse data exist on lymphatics during endocarditis. Fifty-two patients with surgically resected valves were included. Endocarditis was present in 18 aortic and 10 mitral valves. Controls consisted of 15 degenerative aortic and 9 degenerative mitral valves. There were 22 males with endocarditis and 17 males in controls. The mean age was 58 (SD 15) years with endocarditis vs. 62 (SD 13) years for controls. Lymphatics were detected by podoplanin antibody immunohistochemistry and morphometrical analysis was performed. The lymphatic density in endocarditis was 833 (SD 529) vessels/mm(2) (range 0-1707) as compared with 39 (SD 60) vessels/mm(2) (range 0-250) in controls (p=0.000). In endocarditis, the mean lymphatic size was 153 (SD 372) μm(2) ranging from 1 to 2034μm(2), whereas it was 30 (SD 29) μm(2), with maximum 90μm(2) and minimum 2μm(2) in controls (p=0.000). IAL is increased in valves with endocarditis as compared with controls. Lymphatics in heart valves may provide a novel means for treatment strategies against endocarditis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  15. Investigation of Separate Meter-In Separate Meter-Out Control Strategies for Systems with Over Centre Valves

    DEFF Research Database (Denmark)

    Pedersen, Henrik C.; Andersen, Torben Ole; Hansen, Rico Hjerm

    2010-01-01

    of the system and the coupling between the two cylinder chambers. Based on the described controllers the different control strategies are evaluated through via simulations and experimentally on a scale model of an excavator arm. Based on the findings, the performance of the different controllers are discussed...

  16. Desenvolvimento de circuito eletrônico comparador para controle de válvulas de vazões reduzidas = Development of comparative electronic circuit for reduced flow valve control

    Directory of Open Access Journals (Sweden)

    Ana Maria Frattini Fileti

    2011-04-01

    Full Text Available Diversos tipos de válvula de controle de vazão estão disponíveiscomercialmente, sendo a maioria delas apropriada para elevadas vazões e provida de acionamento pneumático para reduzir riscos de explosões em ambientes industriais. As válvulas para vazões reduzidas e baixas pressões são de pequenas dimensões, normalmente eletrônicas e apresentam custo elevado. No presente trabalho foi desenvolvido um sistema de controle eletrônico de vazão por computador on-line, baseado em componentes eletrônicos comuns, em esquema comparativo de tensão. Um amplificador subtrador foi utilizado neste circuito eletrônico, comparando dois valores de tensão para o controle dosentido de rotação e parada do motorredutor de velocidade acoplado à haste da válvula agulha comum. Este sistema de baixo custo se mostrou eficiente e de simples montagem eletrônica. Válvulas de diferentes dimensões foram acopladas com sucesso ao motorredutor comandado pelo circuito eletrônico, conferindo flexibilidade ao atuador desenvolvido.Ensaios de calibração e de determinação de tempo morto são apresentados, obtendo-se como menor faixa de vazão os valores de 0,3 a 3,6 mL s-1.Different types of flow control valves are commercially available but most are only adequate for high flow rates. These are provided with pneumatic devices to reduce explosion risks in industrial plants. Flow-reduced and low pressure valves are small sized, usually driven by analogical signals and very expensive. Current assay developed an on-line computer-aided flow control electronic system made up of common electronic components within a comparative voltage scheme. A subtracted amplifier was employed in the electronic circuit which compares two voltages for rotation direction control and stoppage of speed engine reducer linked to the common valve stem. This low cost system is very efficient and has the advantage of being electronically assembled without any difficulty. Different

  17. Cinematics and sticking of heart valves in pulsatile flow test.

    Science.gov (United States)

    Köhler, J; Wirtz, R

    1991-05-01

    The aim of the project was to develop laboratory test devices for studies of the cinematics and sticking behaviour of technical valve protheses. The second step includes testing technical valves of different types and sizes under static and dynamic conditions. A force-deflection balance was developed in order to load valve rims by static radial forces until sticking or loss of a disc (sticking- and clamping-mould point) with computer-controlled force deflection curves. A second deflection device was developed and used for prosthetic valves in the aortic position of a pulsatile mock circulation loop with simultaneous video-cinematography. The stiffness of technical valve rims varied between 0.20 (St. Jude) and about 1.0 N/micron (metal rim valves). The stiffness decreased significantly with increasing valve size. Sticking under pulsatile flow conditions was in good agreement with the static deflection measurements. Hence, valve sticking with increasing danger of thrombus formation is more likely with a less stiff valve rim. In the case of forces acting perpendicularly to the pendulum axis, the clamping mould-point of the valve can be reached, followed by disc dislodgement.

  18. Face-Sealing Butterfly Valve

    Science.gov (United States)

    Tervo, John N.

    1992-01-01

    Valve plate made to translate as well as rotate. Valve opened and closed by turning shaft and lever. Interactions among lever, spring, valve plate, and face seal cause plate to undergo combination of translation and rotation so valve plate clears seal during parts of opening and closing motions.

  19. Discussion Selection and Using Principles of the P-xylene Unit Adsorbent Tower Program-controlled Valve%对二甲苯装置吸附塔程控阀选型及使用原则探讨

    Institute of Scientific and Technical Information of China (English)

    秦文戈

    2015-01-01

    The p-xylene unit of the Sinopec independent intellectual property rights,using the sequence control program control many sets of program-controlled switch valve order, in order to realize the continuous operation of simulated moving bed adsorption separation process . Among them, the duration of program-controlled valve switch, the synchronicity, the stability of the long period operation and other factors, such as setting parameters of the sequence control program directly affect adsorbent tower pressure stability. This paper key analysis and discuss the principles and matters for attention in the selection and putting-in-service proactively adjustment and operation of the valve ,on the basis of the sinopec process, to facilitate the valve run steady for a long time, reduce the adsorbent tower pressure fluctuations, finally realizes the stable long run of the plant.%中石化自主知识产权的对二甲苯装置,利用顺控程序控制多台程控阀顺序开关,以实现模拟移动床吸附分离工艺的连续运行。其中,程控阀开关时间的长短、切换的同步性、长周期运行的稳定性等因素直接影响吸附塔的压力稳定。本文以中石化的多程控阀工艺为基础,重点分析并探讨了程控阀在选型、投用调试及运行过程中应当遵循的原则和注意事项,以利于程控阀长周期稳定运行,减少吸附塔压力波动,最终实现装置的安稳长运行。

  20. 超磁致伸缩电液伺服阀驱动机构控制系统设计%Design of Control System of Giant Magnetostrictive Electro-hydraulic Servo Valve Driven Machine

    Institute of Scientific and Technical Information of China (English)

    杨朝舒; 何忠波; 李冬伟; 薛光明

    2014-01-01

    为了实现超磁致伸缩电液伺服阀的快速、准确控制,论述了基于PWM控制的超磁致伸缩电液伺服阀的基本结构和工作原理,设计了基于PicoScope2203数字示波器和STC89C51单片机的超磁致伸缩材料电液伺服阀驱动机构的控制系统。结果表明:该控制系统具有控制精度高、控制迅速、集成度高、操作便捷等特点。%In order to achieve the speedy and precision control of electro⁃hydraulic servo valve based on giant magnetostrictive material, the basic structure and working principle of a kind of Electro⁃hydraulic Servo Valve based on giant magnetostrictive material with PWM control was discussed. A control system for the giant magnetostrictive electro⁃hydraulic servo valve driven machine based on PicoScope2203 Digital Oscilloscope and STC89C51 series MCU was designed. The results show that the control system has properties of high speed and precision, highly integrated and convenient for operation, and etc.

  1. 单体泵断油过程中控制阀区域流场特性%Flow Characteristics of Solenoid Control Valve During Fuel Stopping Process for the Unit Pump

    Institute of Scientific and Technical Information of China (English)

    仇滔; 雷艳; 彭璟; 李旭初; 李彬

    2013-01-01

    The solenoid valve in the unit pump system (UPS) controls the pressure buildup within the highpressure fuel line.When it is opened,the high-pressure fuel flows with high velocity from the narrow cross-section into the low-pressure fuel line.During its operation,the flow in the field of solenoid valve is quite complex and affects the performance of UPS.This study presents a visualization test method of the solenoid valve of the UPS.For the optical observation,a glass window was incorporated into the pump.The bubbles induced by the cavitation under various operating conditions were observed by a high-speed camera.All color images were transformed into the gray pictures.Simulation was conducted on the basis of the test data such as the pressure and the displacement of valve core.The test results show that cavitation phenomenon occurs during the opening process of control valve.The simulated results of cavitation regulation in control valve agree well with the experimental results.Simulation results show that cavitations in the control valve mainly occur at three positions,they are,the cone angle of valve port,the downstream of cone angle and the clearance between the valve stop and the core.The reasons of cavitation generated in those positions were discussed based on the simulation results of the flow and the pressure fields.%电控单体泵控制阀打开将导通高低压油路,实现断油控制.在断油过程中,大量高压燃油将通过控制阀狭小区域高速流入低压油路,该区域流场十分复杂,对单体泵卸压断油特性影响很大.在电控单体泵泵体上设计了光学透视窗口,采用高速摄像仪器,获得控制阀开启过程在不同开度下控制阀出口端的流场照片,并对照片进行处理.结合测量获得的控制阀位移以及对应的进出口瞬态压力,采用三维仿真软件开展了控制阀区域瞬态流场的仿真计算.试验证明了该区域在阀打开过程中存在两相流.仿真表明控制

  2. Aortic valve replacement

    DEFF Research Database (Denmark)

    Kapetanakis, Emmanouil I; Athanasiou, Thanos; Mestres, Carlos A

    2008-01-01

    BACKGROUND AND AIMS OF THE STUDY: Prompted by anecdotal evidence and observations by surgeons, an investigation was undertaken into the potential differences in implanted aortic valve prosthesis sizes, during aortic valve replacement (AVR) procedures, between northern and southern European...... countries. METHODS: A multi-institutional, non-randomized, retrospective analysis was conducted among 2,932 patients who underwent AVR surgery at seven tertiary cardiac surgery centers throughout Europe. Demographic and perioperative variables including valve size and type, body surface area (BSA) and early...

  3. GIANT PROSTHETIC VALVE THROMBUS

    Directory of Open Access Journals (Sweden)

    Prashanth Kumar

    2015-04-01

    Full Text Available Mechanical prosthetic valves are predisposed to bleeding, thrombosis & thromboembolic complications. Overall incidence of thromboembolic complications is 1% per year who are on oral anticoagulants, whereas bleeding complications incidence is 0.5% to 6.6% per year. 1, 2 Minimization of Scylla of thromboembolic & Charybdis of bleeding complication needs a balancing act of optimal antithrombotic therapy. We are reporting a case of middle aged male patient with prosthetic mitral valve presenting in heart failure. Patient had discontinued anticoagulants, as he had subdural hematoma in the past. He presented to our institute with a giant prosthetic valve thrombus.

  4. Danfos: Thermostatic Radiator Valves

    DEFF Research Database (Denmark)

    Gregersen, Niels; Oliver, James; Hjorth, Poul G.

    2000-01-01

    This problem deals with modelling the flow through a typical Danfoss thermostatic radiator valve.Danfoss is able to employ Computational Fluid Dynamics (CFD) in calculations of the capacity of valves, but an experienced engineer can often by rules of thumb "guess" the capacity, with a precision...... similar to the one achieved by the expensive and time-consuming CFD calculations. So CFD is only used in case of entirely new designs or where a very detailed knowledge of the flow is required. Even though rules of thumb are useful for those, who have developed them, Danfoss needs an objective and general...... method that can be used to predict the performance of valves....

  5. A valve disk

    Energy Technology Data Exchange (ETDEWEB)

    Khayrullin, N.A.; Isayev, B.N.; Kruglov, S.A.; Molokanov, Yu.K.; Shchelkunov, V.A.; Shegay, V.R.; Vizhgorodskiy, B.N.

    1982-01-01

    A valve disk is proposed which includes a horizontal bed, on which there are laminar valves arranged in staggered order. To ensure the stable and effective operation of the disk in a broad range of loads by compensating for the direct flow and the partial sectioning of the disk bed, it is equipped with compensating elements installed in openings in the bed and hinged with it. They are made in the form of straight, triangular prisms with ports in the bases. The prisms are installed with the capability of movement relative to the disk bed. The valves are positioned on the upper lateral facets of the compensating elements.

  6. Antithrombotic Therapy in Patients with Prosthetic Heart Valves

    Directory of Open Access Journals (Sweden)

    Mohamed HA

    2009-01-01

    Full Text Available Patients with mechanical valve prostheses require a lifelong anticoagulant treatment. The combined use of Warfarin and low-dose aspirin appears to reduce the risk of valve thrombosis and systemic embolism at a low risk of bleeding. The management of women with prosthetic heart valves during pregnancy poses a particular challenge, as there are no available controlled clinical trials to provide guidelines for effective antithrombotic therapy. Oral anticoagulants, such as Warfarin, cause foetal embryopathy; unfractionated heparin and low-molecular-weight heparin have been reported to be ineffective in preventing thromboembolic complications.This article discusses the available data and the most recent guidelines in the antithrombotic management of patients with prosthetic valves, and antithrombotic therapy in various clinical situations such as pregnant women with prosthetic heart valves, and patients with prosthetic heart valves undergoing noncardiac surgery.

  7. Efficient control of servo pneumatic actuator system utilizing by-pass valve and digital sliding mode

    Indian Academy of Sciences (India)

    Vladislav Blagojević; Dragan Šešlija; Miodrag Stojiljković; Slobodan Dudić

    2013-04-01

    The issue of energy saving nowadays is very crucial. Pneumatic systems, constituting an important segment of almost every industry, represent large energy consumers. Also, a significant problem with servo pneumatic actuators is achieving accuracy in positioning. The higher the positioning accuracy, the higher the compressed air consumption is. This paper presents a new solution of the positioning control algorithm which unifies digital control of variable structure and sliding working mode and inter chamber cross-flow. The experiments demonstrated that this control algorithm provides a satisfactory positioning accuracy and robustness of the system, simultaneously reducing compressed air consumption by as much as 29.5%.

  8. JetValve: Rapid manufacturing of biohybrid scaffolds for biomimetic heart valve replacement.

    Science.gov (United States)

    Capulli, Andrew K; Emmert, Maximillian Y; Pasqualini, Francesco S; Kehl, Debora; Caliskan, Etem; Lind, Johan U; Sheehy, Sean P; Park, Sung Jin; Ahn, Seungkuk; Weber, Benedikt; Goss, Josue A; Hoerstrup, Simon P; Parker, Kevin Kit

    2017-07-01

    Tissue engineered scaffolds have emerged as a promising solution for heart valve replacement because of their potential for regeneration. However, traditional heart valve tissue engineering has relied on resource-intensive, cell-based manufacturing, which increases cost and hinders clinical translation. To overcome these limitations, in situ tissue engineering approaches aim to develop scaffold materials and manufacturing processes that elicit endogenous tissue remodeling and repair. Yet despite recent advances in synthetic materials manufacturing, there remains a lack of cell-free, automated approaches for rapidly producing biomimetic heart valve scaffolds. Here, we designed a jet spinning process for the rapid and automated fabrication of fibrous heart valve scaffolds. The composition, multiscale architecture, and mechanical properties of the scaffolds were tailored to mimic that of the native leaflet fibrosa and assembled into three dimensional, semilunar valve structures. We demonstrated controlled modulation of these scaffold parameters and show initial biocompatibility and functionality in vitro. Valves were minimally-invasively deployed via transapical access to the pulmonary valve position in an ovine model and shown to be functional for 15 h. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Surgical double valve replacement after transcatheter aortic valve implantation and interventional mitral valve repair.

    Science.gov (United States)

    Wendeborn, Jens; Donndorf, Peter; Westphal, Bernd; Steinhoff, Gustav

    2013-11-01

    Transcatheter aortic valve implantation, as well as interventional mitral valve repair, offer reasonable therapeutic options for high-risk surgical patients. We report a rare case of early post-interventional aortic valve prosthesis migration to the left ventricular outflow tract, with paravalvular leakage and causing severe mitral valve regurgitation. Initial successful interventional mitral valve repair using a clipped edge-to-edge technique revealed, in a subsequent procedure, the recurrence of mitral valve regurgitation leading to progressive heart failure and necessitating subsequent surgical aortic and mitral valve replacement.

  10. The safety relief valve handbook design and use of process safety valves to ASME and International codes and standards

    CERN Document Server

    Hellemans, Marc

    2009-01-01

    The Safety Valve Handbook is a professional reference for design, process, instrumentation, plant and maintenance engineers who work with fluid flow and transportation systems in the process industries, which covers the chemical, oil and gas, water, paper and pulp, food and bio products and energy sectors. It meets the need of engineers who have responsibilities for specifying, installing, inspecting or maintaining safety valves and flow control systems. It will also be an important reference for process safety and loss prevention engineers, environmental engineers, and plant and process designers who need to understand the operation of safety valves in a wider equipment or plant design context. . No other publication is dedicated to safety valves or to the extensive codes and standards that govern their installation and use. A single source means users save time in searching for specific information about safety valves. . The Safety Valve Handbook contains all of the vital technical and standards informat...

  11. Mitral Valve Disease

    Science.gov (United States)

    ... for more information on procedures, news, and pre- & post-operative care. Section Navigation Select Topic Aortic Valve Disease ... is most commonly caused by inflammation from rheumatic fever, a disease that is related to strep infections; ...

  12. Pulmonary valve stenosis

    Science.gov (United States)

    ... valvuloplasty - pulmonary Images Heart valves References Carabello BA. Valvular heart disease. In: Goldman L, Schafer AI, eds. Goldman's Cecil ... Saunders; 2016:chap 69. Otto CM, Bownow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ...

  13. Mitral valve regurgitation

    Science.gov (United States)

    ... and dentist if you have a history of heart valve disease or congenital heart disease before treatment. Some people ... the middle Heart, front view References Carabello BA. Valvular heart disease. In: Goldman L, Schafer AI, eds. Goldman's Cecil ...

  14. Mitral Valve Prolapse

    Science.gov (United States)

    ... Kawasaki Disease Long Q-T Syndrome Marfan Syndrome Metabolic Syndrome Mitral Valve Prolapse Myocardial Bridge Myocarditis Obstructive Sleep Apnea Pericarditis Peripheral Vascular Disease Rheumatic Fever Sick Sinus Syndrome Silent Ischemia Stroke Sudden ...

  15. Raloxifene attenuates Gas6 and apoptosis in experimental aortic valve disease in renal failure

    Science.gov (United States)

    Abedat, Suzan; Beeri, Ronen; Valitsky, Michael; Daher, Sameh; Kott-Gutkowski, Miriam; Gal-Moscovici, Anca; Sosna, Jacob; Rajamannan, Nalini M.; Lotan, Chaim

    2011-01-01

    Renal failure is associated with aortic valve calcification. Using our rat model of uremia-induced reversible aortic valve calcification, we assessed the role of apoptosis and survival pathways in that disease. We also explored the effects of raloxifene, an estrogen receptor modulator, on valvular calcification. Gene array analysis was performed in aortic valves obtained from three groups of rats (n = 7 rats/group): calcified valves obtained from rats fed with uremic diet, valves after calcification resolution following diet cessation, and control. In addition, four groups of rats (n = 10 rats/group) were used to evaluate the effect of raloxifene in aortic valve calcification: three groups as mentioned above and a fourth group fed with the uremic diet that also received daily raloxifene. Evaluation included imaging, histology, and antigen expression analysis. Gene array results showed that the majority of the altered expressed genes were in diet group valves. Most apoptosis-related genes were changed in a proapoptotic direction in calcified valves. Apoptosis and decreases in several survival pathways were confirmed in calcified valves. Resolution of aortic valve calcification was accompanied by decreased apoptosis and upregulation of survival pathways. Imaging and histology demonstrated that raloxifene significantly decreased aortic valve calcification. In conclusion, downregulation of several survival pathways and apoptosis are involved in the pathogenesis of aortic valve calcification. The beneficial effect of raloxifene in valve calcification is related to apoptosis modulation. This novel observation is important for developing remedies for aortic valve calcification in patients with renal failure. PMID:21335463

  16. Design of pneumatic proportional flow valve type 5/3

    Science.gov (United States)

    Laski, P. A.; Pietrala, D. S.; Zwierzchowski, J.; Czarnogorski, K.

    2017-08-01

    In this paper the 5/3-way pneumatic, proportional flow valve was designed and made. Stepper linear actuator was used to move the spool. The valve is controlled by the controlled based on a AVR microcontroller. Virtual model of the valve was created in CAD. The real element was made based on a standard 5/3-way manually actuated valve with hand lever, which was dismounted and replaced by linear stepper motor. All the elements was mounted in a specially made housing. The controller consists of microcontroller Atmega16, integrated circuit L293D, display, two potentiometers, three LEDs and six buttons. Series of research was also conducted. Simulation research were performed using CFD by the Flow Simulation addition to SolidWorks. During the experiments the valve characteristics of flow and pressure was determined.

  17. Experimental study for flow characteristics and performance evaluation of butterfly valves

    Science.gov (United States)

    Kim, C. K.; Yoon, J. Y.; Shin, M. S.

    2010-08-01

    The industrial butterfly valves have been applied to transport a large of fluid with various fields of industry. Also, these are mainly used a control of fluid flux to the water and waste-water pipeline. Present, butterfly valves are manufacturing for multiplicity shape of bodies and discs with many producers. However, appropriate performance evaluation was not yet accomplished to compare about these valves through experiments. This study is performed the experiment of flow characteristics and performance of manufactured 400A butterfly valves for the water and waste pipeline, and compared experimental results. We performed experiments that were controlled fixed a differential pressure condition (1 psi) and the range of the flow rate conditions (500 m3/hr ~ 2500 m3/hr), and also opened the disc of valves to a range of angle from 9 degree to 90 degree. We investigated and compared the valve flow coefficient and the valve loss coefficient of results through experiments with each butterfly valve.

  18. Automatic Mesh Generation of Hybrid Mesh on Valves in Multiple Positions in Feedline Systems

    Science.gov (United States)

    Ross, Douglass H.; Ito, Yasushi; Dorothy, Fredric W.; Shih, Alan M.; Peugeot, John

    2010-01-01

    Fluid flow simulations through a valve often require evaluation of the valve in multiple opening positions. A mesh has to be generated for the valve for each position and compounding. The problem is the fact that the valve is typically part of a larger feedline system. In this paper, we propose to develop a system to create meshes for feedline systems with parametrically controlled valve openings. Herein we outline two approaches to generate the meshes for a valve in a feedline system at multiple positions. There are two issues that must be addressed. The first is the creation of the mesh on the valve for multiple positions. The second is the generation of the mesh for the total feedline system including the valve. For generation of the mesh on the valve, we will describe the use of topology matching and mesh generation parameter transfer. For generation of the total feedline system, we will describe two solutions that we have implemented. In both cases the valve is treated as a component in the feedline system. In the first method the geometry of the valve in the feedline system is replaced with a valve at a different opening position. Geometry is created to connect the valve to the feedline system. Then topology for the valve is created and the portion of the topology for the valve is topology matched to the standard valve in a different position. The mesh generation parameters are transferred and then the volume mesh for the whole feedline system is generated. The second method enables the user to generate the volume mesh on the valve in multiple open positions external to the feedline system, to insert it into the volume mesh of the feedline system, and to reduce the amount of computer time required for mesh generation because only two small volume meshes connecting the valve to the feedline mesh need to be updated.

  19. Minimising life cycle costs of automated valves in offshore platforms

    Energy Technology Data Exchange (ETDEWEB)

    Yli-Petays, Juha [Metso Automation do Brasil Ltda., Rio de Janeiro, RJ (Brazil); Niemela, Ismo [Metso Automation, Imatra (Finland)

    2012-07-01

    Automated process valves play an essential role in offshore platforms operation. If you are able to optimize their operation and maintenance activities you can receive extensive operational savings with minimal investment. Valves used in offshore platforms doesn't differentiate that much from the valves used in downstream but there are certain specialties, which makes the operations more challenging in offshore: Process valves are more difficult to access and maintain because of space limitations. Also spare part inventories and deliveries are challenging because of offshore platform's remote location. To overcome these challenges usage of digital positioners with diagnostic features has become more common because predictive maintenance capabilities enable possibilities to plan the maintenance activities and this way optimise the spare part orders regarding to valves. There are intelligent controllers available for control valves, automated on/off valves as well as ESD-valves and whole network of automated valves on platforms can be controlled by intelligent valve controllers. This creates many new opportunities in regards of optimized process performance or predictive maintenance point-of-view. By means of intelligent valve controllers and predictive diagnostics, condition monitoring and maintenance planning can also be performed remotely from an onshore location. Thus, intelligent valve controllers provide good way to minimize spending related to total cost of ownership of automated process valves. When purchase value of control valve represent 20% of TCO, intelligent positioner and predictive maintenance methods can enable as high as 30% savings over the life cycle of asset so basically it benefit savings higher than whole investment of monitored asset over its life cycle. This is mainly achieved through the optimized maintenance activities since real life examples has shown that with time based maintenance (preventive maintenance) approach 70% of

  20. Thrombogenicity and Reoperation of the St. Jude Medical Silzone (R) valve : A comparison with the conventional St. Jude medical valve

    NARCIS (Netherlands)

    Stalenhoef, JE; Mellema, EC; Veeger, NJGM; Ebels, T

    2003-01-01

    Background and aim of the study: The St. Jude Medical Silzone(R) valve was withdrawn from the market after an interim analysis of the AVERT study revealed a 2.76% incidence of paravalvar leakage leading to valve re-replacement, compared with only 1.02% in the control group. Additionally, an increase

  1. 无凸轮轴发动机电液驱动配气机构阻尼孔优化设计%Optimization of Orifices on Electro-hydraulic Control Camless Valve Actuator

    Institute of Scientific and Technical Information of China (English)

    谷艳华; 胡乃硕; 高峰军; 李华; 王有坤; 郭英男

    2012-01-01

    The optimized design of orifices in the electro-hydraulic control valve actuator will affect the response and the impact of valve in the camless engine, and thus affect all aspects performance of engine. The mathematical model of the orifices in the valve actuator was designed, and the effects of the orifice ' s diameter to the velocity during opening and landing were analyzed. The model of the camless electro-hydraulic valve actuator was built by using AMESim, the analysis of the influence to the diameter and related position of the valve orifices was done, the results showed that the orifice diameter decreased or the related position of damping chamber orifice increased resulted in the delay of opening time, and the orifice diameter decreased or the related position of main line orifice decreased resulted in the delay of closing time. The parameters of orifices diameter and position were optimized, and the demand of the valve was met by the optimized parameters through the experiments.%无凸轮轴发动机电液驱动配气机构中节流阀阻尼孔的优化设计直接影响气门运动及时响应性能和气门落座冲击性能,进而影响发动机性能.建立了配气机构中节流阀阻尼孔的数学模型,并利用该模型研究了阻尼孔直径对气门开启和落座的影响.使用AMESim搭建了配气机构的仿真模型,研究阻尼孔孔径和相对位置对气门运动的影响.结果表明,阻尼孔直径减小或者阻尼腔阻尼孔相对位置上升会使气门延迟开启;阻尼孔直径减小或者主油路阻尼孔相对位置下降会使气门延迟关闭.优化了阻尼孔孔径和位置参数,试验表明阻尼孔优化设计结果满足发动机对配气机构中气门运动的要求.

  2. Control of fast non linear systems - application to a turbo charged SI engine with variable valve timing; controle des systemes rapides non lineaires - application au moteur a allumage commande turbocompresse a distribution variable

    Energy Technology Data Exchange (ETDEWEB)

    Colin, G.

    2006-10-15

    Spark ignition engine control has become a major issue for the compliance with emissions legislation while ensuring driving comfort. Engine down-sizing is one of the promising ways to reduce fuel consumption and resulting CO{sub 2} emissions. Combining several existing technologies such as supercharging and variable valve actuation, down-sizing is a typical example of the problems encountered in Spark Ignited (SI) engine control: nonlinear systems with saturation of actuators; numerous major physical phenomena not measurable; limited computing time; control objectives (consumption, pollution, performance) often competing. A methodology of modelling and model-based control (internal model and predictive control) for these systems is also proposed and applied to the air path of the down-sized engine. Models, physicals and generics, are built to estimate in-cylinder air mass, residual burned gases mass and air scavenged mass from the intake to the exhaust. The complete and generic engine torque control architecture for the turbo-charged SI engine with variable cam-shaft timing was tested in simulation and experimentally (on engine and vehicle). These tests show that new possibilities are offered in order to decrease pollutant emissions and optimize engine efficiency. (author)

  3. The ATWS analysis of one control rod withdraw out of the HTR-10GT core in addition with bypass valve failure

    Energy Technology Data Exchange (ETDEWEB)

    Lang, Minggang, E-mail: langmg@tsinghua.edu.cn [Institute of Nuclear and New Energy Technology, Tsinghua University, Room 207, Building B, Nengkelou, Beijing (China); Dong, Yujie [Institute of Nuclear and New Energy Technology, Tsinghua University, Room 503, Building A, Nengkelou, Beijing (China)

    2014-05-01

    The 10 MW high temperature gas cooled test reactor (HTR-10) has been built in Institute of Nuclear and New Energy Technology (INET) and has been operating successfully since the beginning of 2003. The core outlet temperature of HTR-10 is 700 °C. To verify the technology of gas-turbine direct cycle, at first INET had a plan to increase its core outlet temperature to 750 °C and use a helium gas turbine instead of the steam generator (then the reactor is called HTR-10GT). Though HTR-10 has good intrinsic safety, the design basic accidents and beyond design basic accidents of HTR10-GT must be analyzed according to China's nuclear regulations due to changed operation parameters. THERMIX code system is used to study the ATWS accident of one control rod withdrawal out of the core by a mistake. After a control rod in the side reflector was withdrawn out at a speed of 1 cm/s by a mistake, a positive reactivity was inserted and the reactor power increased and the temperature of the core increased. When the neutron flux of power measuring range exceeded 123% and the core outlet temperature was greater than 800 °C, the reactor should scram. It was supposed that all the control rods in the reflectors had been blocked and the reactor could not scram. Thus the accident went on and the core temperature and the system pressure increased but the reactor shutdown at last because of its natural negative temperature reactivity feedback mechanism, in spite of the failure of bypass valve. The residual heat would be removed out of the core by the cavity cooling system. During the accident sequence the maximum fuel temperature was 1283.3 °C. It was a litter than 1230 °C – the fuel temperature limitation of HTR-10. Now the sphere fuel used in HTR-10GT will also be used in HTR-PM and the temperature limitation will be raised to 1620 °C, so the HTR-10GT is safe during the ATWS of one control rod withdrawal out of the core. The paper also compares the analysis result of HTR10-GT

  4. Fault Analysis and Improvement of Hydraulic-controlled Butterfly-valve Control System of Main Pump Outlet of Wanjiazhai YRDP(Yellow River Diversion Project)%万家寨引黄工程主泵出口液控蝶阀控制系统故障分析与改进

    Institute of Scientific and Technical Information of China (English)

    李珍珍

    2014-01-01

    山西省万家寨引黄工程一期泵站泵组出水侧液控蝶阀控制系统采用传统的接触式机械行程开关,由于蝶阀设备运行在大振动、高潮湿环境下,接触式行程开关损坏频度较高,经常导致液控蝶阀行程控制失效或错误,致使泵组非正常停运。在分析液控蝶阀行程开关故障原因的基础上,提出采用非接触式磁控开关进行技术改造的方案,工程实践证明改造工作较好地解决了液控蝶阀的行程控制问题。%The hydraulic-controlled butterfly-valve control system mounted on pump outlet side in the pumping station of Shanxi Wanjiazhai YRDP phase 1 is controlled by the traditional mechanical contact travel switch. The butterfly-valve operates in large vibration and high humidity environment, the contact travel switch is damaged frequently, often leading to the failures and mistakes of the travel control of hydraulic-controlled butterfly-valve, and causing the the abnormal shutdown of the pump unit. Based on analyzing the reasons of the faults of the travel switch of hydraulic-controlled valve, this paper puts forward a technical transformation scheme of adopting the non-contact magnetic-controlled switch. The engineering practice proves that the technical transformation has better solved the problem of the travel control of hydraulic-control butterfly-valve.

  5. Implantation of the CoreValve percutaneous aortic valve.

    Science.gov (United States)

    Lamarche, Yoan; Cartier, Raymond; Denault, André Y; Basmadjian, Arsène; Berry, Colin; Laborde, Jean-Claude; Bonan, Raoul

    2007-01-01

    Surgical aortic valve replacement is the only recommended treatment for significant aortic valve stenosis. Percutaneous aortic valve replacement appears to be a novel option for high-risk patients. We report the implantation of the ReValving system (CoreValve, Paris, France) in a 64-year-old woman who was refused aortic valve replacement surgery for critical aortic stenosis and left ventricular dysfunction because of severe pulmonary fibrosis. After anesthesia, the patient was put on femorofemoral cardiopulmonary bypass, and underwent a balloon valvuloplasty with subsequent retrograde aortic valve replacement by the ReValving system. Transesophageal echocardiographic monitoring of the patient's hemodynamics showed immediate improvements of the valvular area and left ventricular ejection fraction and only traces of paravalvular leaks. The patient was easily weaned from ventilation and resumed activity soon after the surgery. A multidisciplinary approach is presently necessary to offer a reliable and safe procedure.

  6. Controle automático de registros de descarga com acionamento pneumático em unidades de armazenagem agrícola Automatic control of slide gate valves with pneumatic drive in agricultural storage facilities

    Directory of Open Access Journals (Sweden)

    Pedro Luís Andrighetto

    2008-12-01

    Full Text Available Este trabalho apresenta os resultados dos testes de um sistema de posicionamento pneumático usado no controle automático da abertura da gaveta dos registros de descarga. Esses registros são empregados para controlar o carregamento dos grãos por gravidade nos equipamentos de transporte nas unidades de beneficiamento e armazenagem de grãos, tais como os elevadores de caçamba e as correias transportadoras. Os experimentos permitiram avaliar o desempenho do posicionamento da gaveta de um protótipo de registro de descarga, acionada por um cilindro pneumático cuja posição é controlada por um controlador eletrônico do tipo ON-OFF. Nos testes mediu-se a resposta transitória da posição da gaveta a uma mudança em degrau no sinal de referência e foram avaliados o erro de posição, o sobrepassado e a velocidade. Os resultados mostraram a viabilidade do sistema no desempenho do controle da posição, na simplicidade do acionamento e no baixo custo, sendo uma alternativa para automação de instalações agroindustriais.This paper shows the results obtained from tests of a pneumatic positioning system used in the automatic control of the drawer opening in slide gate valves. They are used to control the grain loading by gravity in transport equipments as bucket elevators and belt conveyors in agricultural storage facilities. Experimental tests were carried out to evaluate the performance of drawer positioning in a prototype of slide gate valve that is driven by a pneumatic cylinder with position control carried out by an ON-OFF electronic controller. In the experiments was measured the step response of drawer position, allowing the evaluation of the position error, the overshoot and the velocity. The results show the viability of this solution considering its performance in position control, drive simplicity and low cost. It represents an alternative to automation of agricultural storage facilities.

  7. [Technologies for cardiac valve prostheses].

    Science.gov (United States)

    Nakano, Kiyoharu

    2009-07-01

    To show the technological development of cardiac valve prostheses, a historical review of both mechanical and biological valve prostheses and a current overview of modern cardiac valve devices are provided. Scince the 1st implantation of Starr-Edwards ball valve in 1960, both mechanical and biological valve prostheses have advanced. The valve design, the material of the leaflet and the hausing of mechanical prostheses have improved. Currently, the majority of the mechanical prostheses are bileaflet tilting disc valves made of pyrolytic carbon, which is antithromboembolic. However, anticoagulation therapy with warfarin is still required. As for the bioprostheses, although the fixation and anti-mineralization methods of the tissues improved, the durability of these valves is still limited. For the material of the current biological valves, the porcine aortic valve or bovine pericardium are used. The tissues are fixed by non-pressure or low-pressure method in glutaraldehyde solution. A stented and non-stented valves are available. Epoch-making events in this field are the implantation of new bioprosthetic valves using tissue engineering methods and the development of the transcatheter valve replacement therapies.

  8. Software Implementation of Hydraulic Cylinder Position PID Closed Loop Control in Proportional Valve Control System Using PLC%比例阀控液压缸位置PID闭环控制的PLC软件实现

    Institute of Scientific and Technical Information of China (English)

    李艳杰; 崔天宇; 王海; 马鹤; 苗鑫超

    2013-01-01

    A software implementation method of hydraulic cylinder position PID closed loop control in proportional valve control system using Siemens S7-200 was proposed.The block diagram and ladder program was given,and experimental studies in Festo TP701 proportional hydraulic test bed was done.Experimental studies have shown that the proportion of open-loop control system,using software methods can achieve the closed-loop control of position and other physical quantities,to control the performance of precision and anti-jamming capability to meet the demand of general industrial applications.%提出一种利用西门子S7-200实现比例阀控制系统中液压缸位置PID闭环控制的软件实现方法,给出了程序框图及梯形图程序,并在Festo TP701比例液压试验台上进行实验研究.实验研究表明,开环比例控制系统中,利用软件的方法可实现位置等物理量的闭环控制,控制精度和抗干扰能力等性能可满足一般工业应用的需求.

  9. Balloon Pump with Floating Valves for Portable Liquid Delivery

    Directory of Open Access Journals (Sweden)

    Yuya Morimoto

    2016-03-01

    Full Text Available In this paper, we propose a balloon pump with floating valves to control the discharge flow rates of sample solutions. Because the floating valves were made from a photoreactive resin, the shapes of the floating valves could be controlled by employing different exposure patterns without any change in the pump configurations. Owing to the simple preparation process of the pump, we succeeded in changing the discharge flow rates in accordance with the number and length of the floating valves. Because our methods could be used to easily prepare balloon pumps with arbitrary discharge properties, we achieved several microfluidic operations by the integration of the balloon pumps with microfluidic devices. Therefore, we believe that the balloon pump with floating valves will be a useful driving component for portable microfluidic systems.

  10. Transcatheter Aortic Valve Replacement for Degenerative Bioprosthetic Surgical Valves

    DEFF Research Database (Denmark)

    Dvir, Danny; Webb, John; Brecker, Stephen;

    2012-01-01

    Transcatheter aortic valve-in-valve implantation is an emerging therapeutic alternative for patients with a failed surgical bioprosthesis and may obviate the need for reoperation. We evaluated the clinical results of this technique using a large, worldwide registry.......Transcatheter aortic valve-in-valve implantation is an emerging therapeutic alternative for patients with a failed surgical bioprosthesis and may obviate the need for reoperation. We evaluated the clinical results of this technique using a large, worldwide registry....

  11. Optimization of Control Logic and Operation of the Steam Pump Recirculation Valve%汽泵再循环阀控制逻辑和运行操作优化

    Institute of Scientific and Technical Information of China (English)

    杨宁

    2016-01-01

    The recirculating valve of steam pump of the 600MW coal‐fired units has serious inner leakage in the operating system which will cause high energy consumption and endanger the feed water system .After the dis‐integration check ,we discovered that the recirculating valve was badly damaged by frequently opens and clo‐ses .Through optimizing the control logic of the recirculating valve and the corresponding operation ,it is good to resolve the problem and ensure the equipment safety .%讲述了600 M W燃煤机组的汽泵再循环阀在运行过程中内漏严重,影响给水系统运行安全以及造成汽泵能耗损失;对再循环阀进行解体检查分析,确定汽泵运行再循环阀的频繁开启造成再循环阀吹损严重。通过对汽泵再循环阀的控制逻辑进行优化以及对应的运行操作优化,很好地解决了汽泵再循环阀吹损严重这个问题,保证了设备安全。

  12. Sensorless control of electromagnetic actuators for gas valves in spark ignition engines; Sensorlose Regelung elektromagnetischer Aktuatoren fuer die Betaetigung von Gaswechselventilen im Otto-Motor

    Energy Technology Data Exchange (ETDEWEB)

    Butzmann, S.

    2000-07-01

    A method for sensorless control of the impact speed of the armature of electromagnetic actuators is presented and described in great detail. The control algorithm was implemented in a compact electronic control unit for a 4-cylinder, 16-valve engine and was tested both in the laboratory and in a real engine. The method was first presented in September 1999 at the Frankfurt IHH, where it met with great interest. [German] In dieser Arbeit wurde ein Verfahren zur sensorlosen Regelung der Aufsetzgeschwindigkeit des Ankers bei elektromagnetischen Aktuatoren vorgestellt. Um den Anker zwischen den beiden Seiten des Luftspalts zu bewegen, werden zwei Elektromagnete abwechselnd bestromt, die Bewegung wird dabei von zwei Federn unterstuetzt. Fliesst waehrend eines solchen Umschwingvorgangs ein konstanter Strom durch die Spulen, so nimmt waehrend der Annaeherung an die Polflaeche die Magnetkraft mit der Luftspaltlaenge 1/l{sub L}{sup 2} zu, waehrend die entgegengesetzt wirkende Federkraft nur linear mit der Luftspaltlaenge l{sub L} steigt. Dies fuehrt prinzipiell zu einer unerwuenschten Beschleunigung des Ankers am Ende der Bewegung und damit zu einem harten Aufprall, der Laerm erzeugt und die Aktuatorlebensdauer reduziert. Ausgehend vom idealen Verfahren der zeitoptimalen Regelung, welches allerdings hohe Anforderungen an Sensorik und Rechenleistung stellt, wurde ein Algorithmus hergeleitet, welcher die zur Regelung der Aufsetzgeschwindigkeit erforderlichen Signale aus dem Stromverlauf in den Aktuatorspulen ableitet. Das neue Regelverfahren umgeht daher die Probleme, die durch den Einsatz von Sensoren entstehen. Waehrend der Ankerbewegung werden die Spulen zusaetzlich stimuliert, um eine hoehere Observationsgenauigkeit zu erzielen. Durch Adaption zwischen zwei aufeinanderfolgenden Ventilbetaetigungen und Regelung der Bewegung waehrend der Flugphase kann die Aufsetzgeschwindigkeit des Ankers praezise geregelt werden. Gleichzeitig konnte die zur Regelung erforderliche

  13. Mitral Valve Aneurysm: A Rare Complication of Aortic Valve Endocarditis

    Directory of Open Access Journals (Sweden)

    A Moaref

    2008-11-01

    Full Text Available A 20-year-old intravenous drug abuser man, refered to our hospital with dyspnea and orthopnea. Tranesophagealechocardiography revealed severe aortic regurgitation, healed vegetation of aortic valve and an aneurysm of theanterior leaflet of the mitral valve. The patient was discharged after aortic valve replacement and mitral valverepair.

  14. Research on Valve Body Design of Large Bore Sodium Valve

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Large bore sodium valve is one kind of key equipments of China Demonstration Fast Reactor (CDFR). It is installed in the pipeline before and behind SG units as a locking mechanism. Valve body which is used to bear pressure is the core of sodium valve design.

  15. Transcatheter Aortic Heart Valve Thrombosis

    DEFF Research Database (Denmark)

    Hansson, Nicolaj C; Grove, Erik L; Andersen, Henning R;

    2016-01-01

    BACKGROUND: There is increasing focus on transcatheter heart valve (THV) thrombosis. However, there are limited data on incidence, clinical implications and predisposing factors of THV thrombosis following transcatheter aortic valve replacement (TAVR). OBJECTIVES: We assessed the incidence...

  16. Safety valve for offshore borehole

    Energy Technology Data Exchange (ETDEWEB)

    McGill, H.L.; Randermann, E. Jr.; Musik, O.J.

    1977-10-06

    The invention concerns a new and improved submarine safety valve with a valve element which rotate, which can be used, in emergencies, to separate the wound-up piping which extends into the borehole and to close the production line.

  17. Compressed gas domestic aerosol valve design using high viscous product

    Directory of Open Access Journals (Sweden)

    A Nourian

    2016-10-01

    Full Text Available Most of the current universal consumer aerosol products using high viscous product such as cooking oil, antiperspirants, hair removal cream are primarily used LPG (Liquefied Petroleum Gas propellant which is unfriendly environmental. The advantages of the new innovative technology described in this paper are: i. No butane or other liquefied hydrocarbon gas is used as a propellant and it replaced with Compressed air, nitrogen or other safe gas propellant. ii. Customer acceptable spray quality and consistency during can lifetime iii. Conventional cans and filling technology There is only a feasible energy source which is inert gas (i.e. compressed air to replace VOCs (Volatile Organic Compounds and greenhouse gases, which must be avoided, to improve atomisation by generating gas bubbles and turbulence inside the atomiser insert and the actuator. This research concentrates on using "bubbly flow" in the valve stem, with injection of compressed gas into the passing flow, thus also generating turbulence. The new valve designed in this investigation using inert gases has advantageous over conventional valve with butane propellant using high viscous product (> 400 Cp because, when the valving arrangement is fully open, there are negligible energy losses as fluid passes through the valve from the interior of the container to the actuator insert. The use of valving arrangement thus permits all pressure drops to be controlled, resulting in improved control of atomising efficiency and flow rate, whereas in conventional valves a significant pressure drops occurs through the valve which has a complex effect on the corresponding spray.

  18. 停堆装置落球阀试验台架控制系统设计%Design of Control System for Test Platform of Reactor Shutdown System's Ball Dropping Valve

    Institute of Scientific and Technical Information of China (English)

    姚启欣; 何学东

    2011-01-01

    停堆装置落球阀是全新研制的核安全级设备,需通过充分的试验来对设计进行验证.落球阀试验台架控制系统用于试验台架中落球阀驱动机构样机的控制、监测和保护,并提供试验数据采集,是验证设计方案的主要手段.提出了用PLC、步进电机、位置指示器构成的控制系统方案;完成了设备选型、原理设计、系统集成调试和改进;对工程应用中拟采用的控制电路、部件进行了测试.%The newly designed ball dropping valve for the reactor shutdown system is a nuclear safety class equipment, and its design needs to be verified through substantial experiments. The control system of the test platform for the ball dropping valve is built to control, survey and protect a testing prototype of the valve's driving component, and also to provide the methods of data collection and design scheme verification during the test. A control scheme which consists of PLC, stepping motor and position indicator is proposed,the model selection, control principle design and system integration and upgrading have been conducted, and some control circuit and components to be used are fully tested.

  19. Nasal valve surgery.

    Science.gov (United States)

    Apaydin, Fazil

    2011-04-01

    Nasal obstruction can be due to internal and external valve problems that can be seen before and after rhinoplasty. The main scope of this article is to concentrate on surgical solutions to these problems. To overcome nasal obstruction at the internal valve, spreader grafts, spreader flaps, upper lateral splay graft, butterfly graft, flaring suture, M-plasty, Z-plasty, and suspension sutures have been described. The management of the external valve problems is possible by using lateral crural dissection and repositioning, lateral crural strut grafts, alar battens, lateral crural turn-in flap, alar rim grafts, and various other methods. It is not easy to decide which techniques would work best in every case. After a thorough examination and analysis, the underlying cause of the nasal obstruction can be understood, and one or multiple procedures can be chosen according to each individual problem.

  20. Percutaneous mitral valve repair.

    Science.gov (United States)

    Gillinov, A Marc; Liddicoat, John R

    2006-01-01

    Surgical mitral valve repair is the procedure of choice to treat mitral regurgitation of all etiologies. Whereas annuloplasty is the cornerstone of mitral valve repair, a variety of other surgical techniques are utilized to correct dysfunction of the leaflets and subvalvular apparatus; in most cases, surgical repair entails application of multiple repair techniques in each patient. Preclinical studies and early human experience have demonstrated that some of these surgical repair techniques can be performed using percutaneous approaches. Specifically, there has been great progress in the development of novel technology to facilitate percutaneous annuloplasty and percutaneous edge-to-edge repair. The objectives of this report were to (1) discuss the surgical foundations for these percutaneous approaches; (2) review device design and experimental and clinical results of percutaneous valve repair; and (3) address future directions, including the key challenges of patient selection and clinical trial design.

  1. Control circuit for air-jet loom solenoid valve based on ARM7%基于ARM7的喷气织机电磁阀控制电路

    Institute of Scientific and Technical Information of China (English)

    郭张军; 吴震宇; 刘凤臣

    2012-01-01

    In order to complete the real-time control of air-jet loom high frequency solenoid valve, and to promote the fault detection ability of solenoid valve when they work, a control system of high speed driving and current detecting feedback of solenoid valve with ARM7 was designed. ARM7 process chip LPC2478 was used as microcontroller, then an output line expansion circuit was designed with complex programmable logic device( CPLD) on the basis of microprocessor date/address bus. A high speed driving circuit was designed by the high, low voltage composite technology with the characteristic of air-jet loom solenoid valve. Current detecting part was added for judging the working performance of solenoid valve. The test results show that the system has stable operation, high efficiency. The production quality and efficiency of air-jet loom are improved by the research of current detecting feedback data.%为完成喷气织机高频电磁阀的实时控制,提升对电磁阀工作时的故障检测能力,设计了基于ARM7的电磁阀高速驱动和电流检测反馈控制系统.以ARM7处理器的芯片LPC2478为微控制器,并在数据、地址总线基础上,通过采用复杂可编程逻辑器件(CPLD)扩展了输出口线;针对喷气织机电磁阀高频特性,设计了高、低压复合的驱动控制电路;为判断电磁阀工作性能的优劣,增加了电流检测环节.试验结果表明,该系统运行稳定、高效,通过对电流检测反馈数据的分析,提高了喷气织机生产的质量和效率.

  2. Proportional directional valve based automatic steering system for tractors

    Institute of Scientific and Technical Information of China (English)

    Jin-yi LIU; Jing-quan TAN; En-rong MAO; Zheng-he SONG; Zhong-xiang ZHU‡

    2016-01-01

    Most automatic steering systems for large tractors are designed with hydraulic systems that run on either constant flow or constant pressure. Such designs are limited in adaptability and applicability. Moreover, their control valves can unload in the neutral position and eventually lead to serious hydraulic leakage over long operation periods. In response to the problems noted above, a multifunctional automatic hydraulic steering circuit is presented. The system design is composed of a 5-way-3-position proportional directional valve, two pilot-controlled check valves, a pressure-compensated directional valve, a pressure-compensated flow regulator valve, a load shuttle valve, and a check valve, among other components. It is adaptable to most open-center systems with constant flow supply and closed-center systems with load feedback. The design maintains the lowest pressure under load feedback and stays at the neutral position during unloading, thus meeting the requirements for steering. The steering controller is based on proportional-integral-derivative (PID) running on a 51-microcontroller-unit master control chip. An experimental platform is developed to establish the basic characteristics of the system subject to stepwise inputs and sinusoi-dal tracking. Test results show that the system design demonstrates excellent control accuracy, fast response, and negligible leak during long operation periods.

  3. A cryogenic valve for spacecraft applications

    Science.gov (United States)

    Salerno, L. J.; Spivak, A. L.

    1982-01-01

    Space-compatible cryogenic valves are now required to operate between room and liquid helium temperatures. A remotely controllable cryogenic valve is described, which is made of bellows-type stainless steel and is operated by a miniature dc motor with integral gearset (485:1) at a nominal voltage of 28 Vdc. The power transmission provides a further reduction of 7.2:1 to give an overall gear ratio of nearly 3500:1, assuring reliability of operation at low temperatures. Valve performance (leak rate) data are presented at LN2, LHe, and SfHe temperatures at delivered torques of 18, 27, 31, and 35 N-m. At a closing torque of 31 N-m, a leak rate of 0.028 scc/sec was achieved at 2 K, while at a torque of 18 N-m the leak rate at 300 K was less than 3 x 10 to the -9th scc/sec.

  4. Building valve amplifiers

    CERN Document Server

    Jones, Morgan

    2013-01-01

    Building Valve Amplifiers is a unique hands-on guide for anyone working with tube audio equipment--as an electronics hobbyist, audiophile or audio engineer. This 2nd Edition builds on the success of the first with technology and technique revisions throughout and, significantly, a major new self-build project, worked through step-by-step, which puts into practice the principles and techniques introduced throughout the book. Particular attention has been paid to answering questions commonly asked by newcomers to the world of the valve, whether audio enthusiasts tackling their first build or

  5. SAFETY SHUTOFF VALVE

    DEFF Research Database (Denmark)

    2010-01-01

    It is disclosed a shut-off valve which acts automatically and has a fully mechanical performance with respect to the loosing of the tower-shape part balance under the effect of the special acceleration Which is arisen from the quakes waves or serious vibrations, while such vibrations are mainly...... resulted from collision or effusion. A static tower has been applied for the main core of this part of the valve which loses balance state under the effect of collision and bounces to the neighboring part, which results in release of the catch and blockage of the gas passing channel....

  6. Pulsatile prosthetic valve flows.

    Science.gov (United States)

    Phillips, W M; Snyder, A; Alchas, P; Rosenberg, G; Pierce, W S

    1980-01-01

    The laser Doppler system has been established as a useful tool for eliciting the properties of simulated cardiovascular flows, and thus for comparative studies of flow properties of prosthetic valves. Significant differences among valve types and between models of one type have been documented. The complex variations of velocity profiles with time show that comparisons must be made for unsteady pulsatile rather than steady flow, despite the volume and complexity of the data required. Future studies will include methods of compacting the data presentation and improving the details of the experimental stimulation.

  7. Valve stem and packing assembly

    Energy Technology Data Exchange (ETDEWEB)

    Wordin, J.J.

    1990-12-31

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele`s pivot. The Schiele`s pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele`s pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele`s pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

  8. A capillary valve for microfluidic systems.

    Energy Technology Data Exchange (ETDEWEB)

    Cummings, Eric B.; Kanouff, Michael P.; Rush, Brian M.

    2004-10-01

    Microfluidic systems are becoming increasingly complicated as the number of applications grows. The use of microfluidic systems for chemical and biological agent detection, for example, requires that a given sample be subjected to many process steps, which requires microvalves to control the position and transport of the sample. Each microfluidic application has its own specific valve requirements and this has precipitated the wide variety of valve designs reported in the literature. Each of these valve designs has its strengths and weaknesses. The strength of the valve design proposed here is its simplicity, which makes it easy to fabricate, easy to actuate, and easy to integrate with a microfluidic system. It can be applied to either gas phase or liquid phase systems. This novel design uses a secondary fluid to stop the flow of the primary fluid in the system. The secondary fluid must be chosen based on the type of flow that it must stop. A dielectric fluid must be used for a liquid phase flow driven by electroosmosis, and a liquid with a large surface tension should be used to stop a gas phase flow driven by a weak pressure differential. Experiments were carried out investigating certain critical functions of the design. These experiments verified that the secondary fluid can be reversibly moved between its 'valve opened' and 'valve closed' positions, where the secondary fluid remained as one contiguous piece during this transport process. The experiments also verified that when Fluorinert is used as the secondary fluid, the valve can break an electric circuit. It was found necessary to apply a hydrophobic coating to the microchannels to stop the primary fluid, an aqueous electrolyte, from wicking past the Fluorinert and short-circuiting the valve. A simple model was used to develop valve designs that could be closed using an electrokinetic pump, and re-opened by simply turning the pump off and allowing capillary forces to push the secondary

  9. Transcatheter Valve-in-Valve: A Cautionary Tale.

    Science.gov (United States)

    Luc, Jessica G Y; Shanks, Miriam; Tyrrell, Benjamin D; Welsh, Robert C; Butler, Craig R; Meyer, Steven R

    2016-09-01

    Transcatheter aortic valve replacement (TAVR) by valve-in-valve (VIV) implantation is an alternative treatment for high-risk patients with a degenerating aortic bioprosthesis. We present a case of transapical TAVR VIV with a 29-mm Edwards SAPIEN XT (ESV) (Edwards Lifesciences, Irvine, CA) into a 29-mm Medtronic Freestyle stentless bioprosthesis (Medtronic Inc, Minneapolis, MN) in which unanticipated dilatation of the Freestyle bioprosthesis resulted in intraprocedural embolization of the TAVR valve, necessitating urgent conversion to a conventional surgical aortic valve replacement (AVR). Our experience suggests that TAVR VIV with the 29-mm ESV in the setting of a degenerated 29-mm Freestyle stentless bioprosthesis must be undertaken with caution.

  10. Influence of Steam Turbine Valve Discharge Characteristics on Power Systems and Its Control Strategy%汽轮机阀门流量特性对电力系统的影响及其控制策略

    Institute of Scientific and Technical Information of China (English)

    盛锴; 刘复平; 刘武林; 寻新; 王伯春; 李劲柏

    2012-01-01

    汽轮机阀门流量特性是影响电力系统稳定性的重要因素,通过建立电网汽轮机及其调速系统、发电机、励磁系统的数学模型,研究了汽轮机调节阀门流量特性对电网安全稳定性的影响机制。数学分析和仿真结果表明,当汽轮机阀门流量特性不佳时,会引起原动机有功功率的周期性波动。针对此现象,提出了调整后的汽轮机调速系统控制策略,该策略能够抑制功率控制方式下的比例—积分—微分控制器的过度调节,有效增加系统阻尼,抑制原动机的功率波动。%Steam turbine valve discharge characteristics are among the important factors affecting the stability of the power systems.The influence mechanism of steam turbine valve discharge characteristics on the security and stability of the power grid is studied through the mathematical modeling of steam turbine and its speed control system,generator and excitation system.Mathematical analysis and simulation results show that cyclic fluctuations of generator active power might be caused by undesired steam turbine valve discharge characteristics.In view of this phenomenon,a modified control strategy of turbine governor modification system is proposed.This strategy can inhibit the excessive accommodation of proportion-integration-differentiation(PID) controller which is based on the power control mode,effectively increases the system damping,and suppresses power fluctuations of the prime mover.

  11. Prosthetic valve thrombosis in a patient with mitral valve replacement.

    Science.gov (United States)

    Bilal, Muhammad; Khan, Muhammad Shahzeb; Haseeb, Abdul; Khan, Abdul Bari

    2015-07-01

    Prosthetic valve thrombosis within one year after mitral valve replacement is rarely seen in patients on warfarin therapy and without any risk factor. Here, we describe a case of a 39-year- old female, who presented with dyspnoea and shortness of breath 11 months after mitral valve replacement. The echocardiogram revealed severe valvular stenosis due to presence of clots on the mitral valve and restricted motion of the mitral leaflets. As a result of deterioration of general condition and haemodynamic un-stability, plan was made to re-operate for her valve replacement surgery. This case report highlights the diagnosis, prevention and management of patients with prosthetic valve thrombosis following mitral valve replacement.

  12. Rotating pulse valve for downhole fluid telemetry systems

    Energy Technology Data Exchange (ETDEWEB)

    Duckworth, A.

    1993-06-01

    An apparatus for generating pressure pulses in a drilling fluid in a drill collar section of a drill string is described comprising: rotating valve means substantially diametrically mounted in a drill string segment, said rotating valve means alternating between a first position corresponding to more resistance to the flow of drilling fluid and a second position corresponding to less resistance to the flow of drilling fluid, said rotating valve means being impelled by the flow of drilling fluid; and restraining means disposed in the drill collar segment, said restraining means restraining said rotating valve means in said first position and releasing said rotating valve means from said first position in response to control signals indicative of a downhole condition.

  13. Valve exploiting the principle of a side channel turbine

    Science.gov (United States)

    Jandourek, Pavel; Pochylý, František; Haban, Vladimír

    2017-04-01

    The presented article deals with a side channel turbine, which can be used as a suitable substitute for a pressure reducing valve. Pressure reducing valves are a source of high hydraulic losses. The aim is to replace them by a side channel turbine. With that in mind, hydraulic losses can be replaced by a production of electrical energy at comparable characteristics of the reducing valve and the side channel turbine. The basis for the design is the loss characteristics of the pressure reducing valve. Thereby create a new kind of turbine valve with speed-controlled flow in dependence of the runner revolution. It is technical innovation and new renewable source of energy, which can be in future used in rehabilitation or projecting of pumped-storage power plants. It also increases the power of the power plant.

  14. Novel liquid equilibrium valving on centrifugal microfluidic CD platform.

    Science.gov (United States)

    Al-Faqheri, Wisam; Ibrahim, Fatimah; Thio, Tzer Hwai Gilbert; Arof, Hamzah; Madou, Marc

    2013-01-01

    One of the main challenges faced by researchers in the field of microfluidic compact disc (CD) platforms is the control of liquid movement and sequencing during spinning. This paper presents a novel microfluidic valve based on the principle of liquid equilibrium on a rotating CD. The proposed liquid equilibrium valve operates by balancing the pressure produced by the liquids in a source and a venting chamber during spinning. The valve does not require external forces or triggers, and is able to regulate burst frequencies with high accuracy. In this work, we demonstrate that the burst frequency can be significantly raised by making just a small adjustment of the liquid height in the vent chamber. Finally, the proposed valve ng method can be used separately or combined with other valving methods in advance microfluidic processes.

  15. Estrategias para Compensar no Linealidades Generadas por Válvulas en Lazos de Control de Flujo Strategies to Compensate Non-Linearities Generated by Valves in Flow Control Loops

    Directory of Open Access Journals (Sweden)

    Rafael E Vásquez

    2007-01-01

    Full Text Available En este trabajo se compararon diferentes estrategias para compensar no linealidades generadas por válvulas en lazos de control de flujo. Se realizó la identificación de un proceso de flujo de líquido incompresible mediante una prueba en planta y se desarrolló un sistema de control por computador. En este sistema fueron implementados un controlador lineal PI y cuatro diferentes estrategias de compensación, usando LabVIEW®. La comparación fue realizada usando como índices de desempeño la integral del valor absoluto del error, el tiempo de estabilización y el sobrepaso. Las estrategias usadas permitieron mejorar el desempeño del controlador lineal en la zona de saturación del actuador. En conclusión, se puede considerar el uso de estos algoritmos para reemplazar elementos como controladores con auto-sintonía o posicionadores no lineales que elevan los costos de inversión y mantenimiento de la plantaIn this work, different strategies to compensate nonlinearities generated by valves in flow control loops were compared. The identification for an incompressible flow process was made through a plant test and a computer control system was developed. In this system a PI linear controller and four different compensation strategies were implemented using LabVIEW™. The comparison was made using the integral of the absolute value of the error, settling time and overshoot as performance indexes. The compared strategies allowed improving the performance of the linear controller in the actuator saturation zone. In conclusion, using these algorithms can be considered to replace elements as self-tuning controllers or nonlinear positioners that raise the inversion and maintenance costs of the plant

  16. An electrochemical active valve

    NARCIS (Netherlands)

    Neagu, C.R.; Gardeniers, J.G.E.; Elwenspoek, M.; Kelly, J.J.

    1997-01-01

    A novel electrochemical microactuator was developed, which operates as an active valve. The microactuator consists of an electrochemical cell and a membrane that deflects because of the pressure of oxygen gas generated by electrolysis. Relatively large pressures (up to tens of bars) can be reached w

  17. Heart valve surgery - discharge

    Science.gov (United States)

    ... ACC guideline for the management of patients with valvular heart disease: executive summary: a report of the American College ... Editorial team. Related MedlinePlus Health Topics Heart Surgery Heart Valve Diseases Browse the Encyclopedia A.D.A.M., Inc. ...

  18. Aortic valve surgery - open

    Science.gov (United States)

    ... Saunders; 2012:chap 61. Otton CM, Bowow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ... Editorial team. Related MedlinePlus Health Topics Heart Surgery Heart Valve Diseases Browse the Encyclopedia A.D.A.M., Inc. ...

  19. Vent Relief Valve Test

    Science.gov (United States)

    2008-01-01

    Shown is the disassembly, examination, refurbishment and testing of the LH2 ( liquid hydrogen) and LOX (liquid oxygen) vent and relief valves for the S-IVB-211 engine stage in support of the Constellation/Ares project. This image is extracted from high definition video and is the highest resolution available.

  20. 基于ANSYS的LNG超低温增压调节阀流体仿真分析%The Finite Element Analysis of the Cryogenic Increase-pressure Control Valve in LNG Based on ANSYS

    Institute of Scientific and Technical Information of China (English)

    王二强; 钟小艳; 赵文峰; 段贤晖

    2015-01-01

    Currently, the Cryogenic Increase-pressure Control Valve in LNG mostly use imported products in the domestic. The price of which is high, and the delivery cycle is long. In order to break through the key technology of the Cryogenic Increase-pressure Control Valve in LNG to reduce product maintenance and repair costs. This article introduces the characteristics of the Cryogenic Increase-pressure Con-trol Valve used in liquefied natural gas(LNG),operating principle, the structural feature and finite element analysis.%LNG超低温增压调节阀门目前大都是使用进口产品,国内对LNG超低温增压调节阀门技术掌握还处于初步阶段。进口的超低温增压调节阀门不仅供货周期长,而且价格昂贵,特别是配件不能在短时间内解决,使国内LNG行业的发展受到严重制约。为了突破LNG超低温增压调节阀门关键技术,降低产品维修、检修费用,该文设计了一种液化天然气用LNG超低温增压调节阀门,介绍了其工作原理、结构特性和有限元仿真分析。

  1. Measurement of reed valve kinematics

    Directory of Open Access Journals (Sweden)

    Fenkl Michael

    2016-01-01

    Full Text Available The measurement of key kinematic parameters of a reed valve movement is necessary for the further development of the reed valve system. These parameters are dependent on the geometry and material properties of the valve. As they directly affect the quantity of air flowing around the valve, a simple and easy to implement measurement of various valve configuration based on the air flow has been devised and is described in this paper, along with its technical parameters and drawbacks when evaluating reed valves used in reciprocating air compressors. Results are presented for a specimen of a compressor under examination. All kinematic parameters, and timing of the opening and closing of the valve, obtained from the measurement are presented and discussed.

  2. Measurement of reed valve kinematics

    Science.gov (United States)

    Fenkl, Michael; Dvořák, Václav; Vít, Tomáš

    2016-03-01

    The measurement of key kinematic parameters of a reed valve movement is necessary for the further development of the reed valve system. These parameters are dependent on the geometry and material properties of the valve. As they directly affect the quantity of air flowing around the valve, a simple and easy to implement measurement of various valve configuration based on the air flow has been devised and is described in this paper, along with its technical parameters and drawbacks when evaluating reed valves used in reciprocating air compressors. Results are presented for a specimen of a compressor under examination. All kinematic parameters, and timing of the opening and closing of the valve, obtained from the measurement are presented and discussed.

  3. Electronic bidirectional valve circuit prevents crossover distortion and threshold effect

    Science.gov (United States)

    Kernick, A.

    1966-01-01

    Four-terminal network forms a bidirectional valve which will switch or alternate an ac signal without crossover distortion or threshold effect. In this network, an isolated control signal is sufficient for circuit turn-on.

  4. Bicuspid aortic valves: Diagnostic accuracy of standard axial 64-slice chest CT compared to aortic valve image plane ECG-gated cardiac CT

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, David J., E-mail: david.murphy@st-vincents.ie [Department of Radiology, St Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland); McEvoy, Sinead H., E-mail: s.mcevoy@st-vincents.ie [Department of Radiology, St Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland); Iyengar, Sri, E-mail: sri.iyengar@nhs.net [Department of Radiology, Plymouth Hospitals NHS Trust, Plymouth Devon PL6 8DH (United Kingdom); Feuchtner, Gudrun, E-mail: Gudrun.Feuchtner@i-med.ac.at [Department of Radiology, Innsbruck Medical University, Anichstr. 35, A-6020 Innsbruck (Austria); Cury, Ricardo C., E-mail: r.cury@baptisthealth.net [Department of Radiology, Baptist Cardiac and Vascular Institute, 8900 North Kendall Drive, Miami, FL 33176 (United States); Roobottom, Carl, E-mail: carl.roobottom@nhs.net [Department of Radiology, Plymouth Hospitals NHS Trust, Plymouth Devon PL6 8DH (United Kingdom); Plymouth University Peninsula Schools of Medicine and Dentistry (United Kingdom); Baumueller, Stephan, E-mail: Hatem.Alkadhi@usz.ch [Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich (Switzerland); Alkadhi, Hatem, E-mail: stephan.baumueller@usz.ch [Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich (Switzerland); Dodd, Jonathan D., E-mail: jonniedodd@gmail.com [Department of Radiology, St Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland)

    2014-08-15

    Objectives: To assess the diagnostic accuracy of standard axial 64-slice chest CT compared to aortic valve image plane ECG-gated cardiac CT for bicuspid aortic valves. Materials and methods: The standard axial chest CT scans of 20 patients with known bicuspid aortic valves were blindly, randomly analyzed for (i) the appearance of the valve cusps, (ii) the largest aortic sinus area, (iii) the longest aortic cusp length, (iv) the thickest aortic valve cusp and (v) valve calcification. A second blinded reader independently analyzed the appearance of the valve cusps. Forty-two age- and sex-matched patients with known tricuspid aortic valves were used as controls. Retrospectively ECG-gated cardiac CT multiphase reconstructions of the aortic valve were used as the gold-standard. Results: Fourteen (21%) scans were scored as unevaluable (7 bicuspid, 7 tricuspid). Of the remainder, there were 13 evaluable bicuspid valves, ten of which showed an aortic valve line sign, while the remaining three showed a normal Mercedes-Benz appearance owing to fused valve cusps. The 35 evaluable tricuspid aortic valves all showed a normal Mercedes-Benz appearance (P = 0.001). Kappa analysis = 0.62 indicating good interobserver agreement for the aortic valve cusp appearance. Aortic sinus areas, aortic cusp lengths and aortic cusp thicknesses of ≥3.8 cm{sup 2}, 3.2 cm and 1.6 mm respectively on standard axial chest CT best distinguished bicuspid from tricuspid aortic valves (P < 0.0001 for all). Of evaluable scans, the sensitivity, specificity, positive and negative predictive values of standard axial chest CT in diagnosing bicuspid aortic valves was 77% (CI 0.54–1.0), 100%, 100% and 70% respectively. Conclusion: The aortic valve is evaluable in approximately 80% of standard chest 64-slice CT scans. Bicuspid aortic valves may be diagnosed on evaluable scans with good diagnostic accuracy. An aortic valve line sign, enlarged aortic sinuses and elongated, thickened valve cusps are specific CT

  5. Experimental apparatus to test air trap valves

    Science.gov (United States)

    Lemos De Lucca, Y. de F.; de Aquino, G. A.; Filho, J. G. D.

    2010-08-01

    It is known that the presence of trapped air within water distribution pipes can lead to irregular operation or even damage to the distribution systems and their components. The presence of trapped air may occur while the pipes are being filled with water, or while the pumping systems are in operation. The formation of large air pockets can produce the water hammer phenomenon, the instability and the loss of pressure in the water distribution networks. As a result, it can overload the pumps, increase the consumption of electricity, and damage the pumping system. In order to avoid its formation, all of the trapped air should be removed through "air trap valves". In Brazil, manufacturers frequently have unreliable sizing charts, which cause malfunctioning of the "air trap valves". The result of these malfunctions causes accidents of substantial damage. The construction of a test facility will provide a foundation of technical information that will be used to help make decisions when designing a system of pipelines where "air trap valves" are used. To achieve this, all of the valve characteristics (geometric, mechanic, hydraulic and dynamic) should be determined. This paper aims to describe and analyze the experimental apparatus and test procedure to be used to test "air trap valves". The experimental apparatus and test facility will be located at the University of Campinas, Brazil at the College of Civil Engineering, Architecture, and Urbanism in the Hydraulics and Fluid Mechanics laboratory. The experimental apparatus will be comprised of various components (pumps, steel pipes, butterfly valves to control the discharge, flow meter and reservoirs) and instrumentation (pressure transducers, anemometer and proximity sensor). It should be emphasized that all theoretical and experimental procedures should be defined while taking into consideration flow parameters and fluid properties that influence the tests.

  6. Experimental apparatus to test air trap valves

    Energy Technology Data Exchange (ETDEWEB)

    Lemos De Lucca, Y de F [CTH-DAEE-USP/FAAP/UNICAMP (Brazil); Aquino, G A de [SABESP/UNICAMP (Brazil); Filho, J G D, E-mail: yvone.lucca@gmail.co [Water Resources Department, University of Campinas-UNICAMP, Av. Albert Einstein, 951, Cidade Universitaria-Barao Geraldo-Campinas, S.P., 13083-852 (Brazil)

    2010-08-15

    It is known that the presence of trapped air within water distribution pipes can lead to irregular operation or even damage to the distribution systems and their components. The presence of trapped air may occur while the pipes are being filled with water, or while the pumping systems are in operation. The formation of large air pockets can produce the water hammer phenomenon, the instability and the loss of pressure in the water distribution networks. As a result, it can overload the pumps, increase the consumption of electricity, and damage the pumping system. In order to avoid its formation, all of the trapped air should be removed through 'air trap valves'. In Brazil, manufacturers frequently have unreliable sizing charts, which cause malfunctioning of the 'air trap valves'. The result of these malfunctions causes accidents of substantial damage. The construction of a test facility will provide a foundation of technical information that will be used to help make decisions when designing a system of pipelines where 'air trap valves' are used. To achieve this, all of the valve characteristics (geometric, mechanic, hydraulic and dynamic) should be determined. This paper aims to describe and analyze the experimental apparatus and test procedure to be used to test 'air trap valves'. The experimental apparatus and test facility will be located at the University of Campinas, Brazil at the College of Civil Engineering, Architecture, and Urbanism in the Hydraulics and Fluid Mechanics laboratory. The experimental apparatus will be comprised of various components (pumps, steel pipes, butterfly valves to control the discharge, flow meter and reservoirs) and instrumentation (pressure transducers, anemometer and proximity sensor). It should be emphasized that all theoretical and experimental procedures should be defined while taking into consideration flow parameters and fluid properties that influence the tests.

  7. Developments in mechanical heart valve prosthesis

    Indian Academy of Sciences (India)

    Kalyani Nair; C V Muraleedharan; G S Bhuvaneshwar

    2003-06-01

    Artificial heart valves are engineered devices used for replacing diseased or damaged natural valves of the heart. Most commonly used for replacement are mechanical heart valves and biological valves. This paper briefly outlines the evolution, designs employed, materials being used,. and important factors that affect the performance of mechanical heart valves. The clinical performance of mechanical heart valves is also addressed. Efforts made in India in the development of mechanical heart valves are also discussed.

  8. Computational Cavitation Flows at Inception and Light Stages on an Axial-Flow Pump Blade and in a Cage-Guided Control Valve

    Institute of Scientific and Technical Information of China (English)

    Sumio SAITO; Masahiro SHIBATA; Hideo FUKAE; Eisuke OUTA

    2007-01-01

    Cavitation flows induced around an axial-flow pump blade and inside a high pressure cage-type valve are simulated by a two-dimensional unsteady Navier-Stokes analysis with the simplest treatment of bubble dynamics. The fluid is assumed as a continuum of homogeneous dispersed mixture of water and vapor nuclei. The analysis is aimed to capture transient stages with high amplitude pressure change during the birth and collapse of the bubble especially at the stage of cavitation inception. By the pump blade analysis, in which the field pressure is moderate,cavitation number of the inception and locations of developed cavitation are found to agree with experimental results in a wide flow range between high incidence and negative incidence. In the valve flow analysis, in which the water pressure of 5MPa is reduced to 2MPa, pressure change responding to the bubble collapse between the vapor pressure lower than 1 KPa and the extreme pressure of higher than 104 KPa is captured through a stable computation. Location of the inception bubble and pressure force to the valve plug is found agree well with the respective experimental features.

  9. Design Method for Fast Switching Seat Valves for Digital Displacement Machines

    DEFF Research Database (Denmark)

    Roemer, Daniel Beck; Johansen, Per; Pedersen, Henrik C.;

    2014-01-01

    Digital Displacement (DD) machines are upcoming technology where the displacement of each pressure chamber is controlled electronically by use of two fast switching seat valves. The effective displacement and operation type (pumping/motoring) may be controlled by manipulating the seat valves...... operation, where switching times must be performed within a few milliseconds. These valve requirements make a simulation based design approach essential, where mechanical strength, thermal dissipation, fluid dynamics and electro-magnetic dynamics must be taken into account. In this paper a complete design...... of the valves. A coupled optimization is finally conducted to optimize the electro-magnetic actuator, leading to a valve design based on the chosen valve topology. The design method is applied to an example DD machine and the resulting valve design fulfilling the requirements is presented....

  10. A normally-closed piezoelectric micro-valve with flexible stopper

    Science.gov (United States)

    Chen, Song; Lu, Song; Liu, Yong; Wang, Jiantao; Tian, Xiaochao; Liu, Guojun; Yang, Zhigang

    2016-04-01

    In the field of controlled drug delivery system, there are still many problems on those reported micro-valves, such as the small opening height, unsatisfactory particle tolerance and high cost. To solve the above problems, a novel normally-closed piezoelectric micro-valve is presented in this paper. The micro-valve was driven by circular unimorph piezoelectric vibrator and natural rubber membrane with high elasticity was used as the valve stopper. The small axial displacement of piezoelectric vibrator can be converted into a large stroke of valve stopper based on hydraulic amplification mechanism. The experiment indicates that maximum hydraulic amplification ratio is up to 14, and the cut-off pressure of the micro-valve is 39kPa in the case of no working voltage. The presented micro valve has a large flow control range (ranging from 0 to 8.75mL/min).

  11. Design Method for Fast Switching Seat Valves for Digital Displacement Machines

    DEFF Research Database (Denmark)

    Roemer, Daniel Beck; Johansen, Per; Pedersen, Henrik C.

    2014-01-01

    Digital Displacement (DD) machines are upcoming technology where the displacement of each pressure chamber is controlled electronically by use of two fast switching seat valves. The effective displacement and operation type (pumping/motoring) may be controlled by manipulating the seat valves...... operation, where switching times must be performed within a few milliseconds. These valve requirements make a simulation based design approach essential, where mechanical strength, thermal dissipation, fluid dynamics and electro-magnetic dynamics must be taken into account. In this paper a complete design...... of the valves. A coupled optimization is finally conducted to optimize the electro-magnetic actuator, leading to a valve design based on the chosen valve topology. The design method is applied to an example DD machine and the resulting valve design fulfilling the requirements is presented....

  12. PARAMETER ESTIMATION OF VALVE STICTION USING ANT COLONY OPTIMIZATION

    Directory of Open Access Journals (Sweden)

    S. Kalaivani

    2012-07-01

    Full Text Available In this paper, a procedure for quantifying valve stiction in control loops based on ant colony optimization has been proposed. Pneumatic control valves are widely used in the process industry. The control valve contains non-linearities such as stiction, backlash, and deadband that in turn cause oscillations in the process output. Stiction is one of the long-standing problems and it is the most severe problem in the control valves. Thus the measurement data from an oscillating control loop can be used as a possible diagnostic signal to provide an estimate of the stiction magnitude. Quantification of control valve stiction is still a challenging issue. Prior to doing stiction detection and quantification, it is necessary to choose a suitable model structure to describe control-valve stiction. To understand the stiction phenomenon, the Stenman model is used. Ant Colony Optimization (ACO, an intelligent swarm algorithm, proves effective in various fields. The ACO algorithm is inspired from the natural trail following behaviour of ants. The parameters of the Stenman model are estimated using ant colony optimization, from the input-output data by minimizing the error between the actual stiction model output and the simulated stiction model output. Using ant colony optimization, Stenman model with known nonlinear structure and unknown parameters can be estimated.

  13. High-fidelity Modelling of Self-regulating Pneumatic Valves

    OpenAIRE

    Pollok, Alexander; Casella, Francesco

    2015-01-01

    In conventional aircraft energy systems, self-regulating pneumatic valves (SRPVs) are used to control the pressure and mass flow of the bleed air. The dynamic behavior of these valves is complex and dependent on several physical phenomena. In some cases, limit cycles can occur, deteriorating performance. This paper presents a complex multiphysical model of SRPVs implemented in Modelica. First, the working-principle is explained, and common challenges in control-system design-problems ...

  14. 控制输水管道瞬态液柱分离的空气阀调压室%Air-valve surge tank for controlling liquid column separation in water supply projects

    Institute of Scientific and Technical Information of China (English)

    杨开林

    2011-01-01

    A new type air-valve surge tank for controlling liquid column separation occured to water supply projects is developed.It consists of a vertical short pipe and air valves installed on the top.The tanks are installed on the main to form a series of local convexities.They are full of water during normal operations.As soon as the water pressure drops to under the atmospheric pressure,air will be sucked into the tank through the air valve to form an air chamber.The air in the tank will be released slowly while the water pressure is greater than the atmospheric pressure.The application indicates that the tank not only can control the negative pressure during hydraulic transients,but also the positive pressure.%提出了用于控制输水管道瞬态液柱分离的新型空气阀调压室,即在输水线路上设置一个短管,短管顶部密封,然后在它顶部设置空气阀。在正常输水时,空气阀关闭,调压室(短管)充满水体,没有气体。当调压室顶部水压下降到大气压以下时,空气阀进气,在调压室中形成气囊,防止输水管道发生液体汽化现象,或者出现超过管道承受能力的高度真空压力。当调压室底部水压超过大气压时,调压室中气体压缩,气体由空气阀缓慢排出,避免发生较大冲击水压。

  15. Design and realization of the Variable period PWM control circuit of the electro-hydraulic proportional valve%变周期PWM电液比例阀控制电路的设计与实现

    Institute of Scientific and Technical Information of China (English)

    王朋; 李文魁

    2012-01-01

    This paper analyses the basic principle of PWM control the electro-hydraulic ,proportional valve. The PWM control circuit is designed based on C8051F340 single chip microcomputer. Variable period PWM signal is generated by programmed PCA module and power is amplified by darlington transistor arrays chip. The experiment shows that the circuit can be configured flexibly and fast responsible and high precision which Satisfies the demand of electro-hydraulic proportional valve control.%分析了脉冲宽度调制(PWM)控制电液比例阀的基本原理,采用C8051F340单片机设计控制电路,通过可编程计数器阵列(PCA)模块编程实现了变周期PWM信号的产生,通过达林顿晶体管阵列芯片实现功率放大。实验表明,该电路具有配置灵活、响应快、精度高等优点,满足电液比例阀控制要求。

  16. Water Hydraulic 2/2 Directional Valve with Plane Piston Structure

    Institute of Scientific and Technical Information of China (English)

    GONG Yongjun; YANG Huayong; WANG Zuwen

    2009-01-01

    Due to the fire resistance and environmental compatibility, using water as the working fluid in hydraulic circuits is receiving an increasing attention by both manufactures and users. This hydraulic directional valve is developed. When new water hydraulic directional valve is designed and manufactured, this paper introduces a water hydraulic 2/2 directional valve and its principle. The valve is composed of a hydraulically operated seat valve and a magnetic 3/2 direction valve. Aimed at the serious leakage and impact generating easily in reversing suddenly, an improved structure of water space seal is changed to direct seal, compaction force between main valve spool and main valve pocket was logically designed and damper in pilot valve port is matched with sensitive cavity in main valve. From the view of flow control, the methods of cavitation resistance of the directional water hydraulic valve are investigated. The computational fluid dynamics approaches are applied to obtain static pressure distributions and cavitation images in the channel of the main stage of the valve with two kinds of structure. The results show that the method of optimized spout can effectively restrain cavitation. The work provides some useful reference for developing water hydraulic control valve with the Dower noise and lower vibration. Meantime, the structural parameters are optimized on the basis of information obtained from simulation. Static test, dynamic test and life test are accomplished, and the results show that the water hydraulic directional valve possesses good property, its pressure loss is 1.1 MPa lower, switching time is shorter than 0.025 s, and its strike crest is 0.8 MPa lower. The valve possess fine dynamic performance with the characteristic rapidly action and lower implusion.

  17. S209FA燃气一蒸汽联合循环Dl l型汽轮机调节阀的电液转换控制%ElectrO-hydrauUc Conversion Control of Dll Steam Turbine Control Valve in S209FA Gas-Steam Combined Cycle Unit

    Institute of Scientific and Technical Information of China (English)

    陈元锁

    2010-01-01

    Introduce the steam path of D11 Steam Turbine in S209FA Gas—Steam Combined Cycle Unit.Explain the control algorithm of the main steam,reheat steam and LP steam control valves.Describe the electro-hydraulic control principle and implementation process of control valves.%对S209FA燃气一蒸汽联合循环DIl型汽轮机的蒸汽流程进行说明;对主蒸汽、再热蒸汽以及低压补汽调节阀的控制计算进行讲解,并对这些调节阀的电液控制原理和实现过程进行叙述。

  18. 小舜江输水泵站液控蝶阀关阀时间及停泵方式改进%Hydraulic control butterfly valve closing vale time and pump stooping method improvement for the Xiaoshunjiang water transfer pump station

    Institute of Scientific and Technical Information of China (English)

    陈培兴

    2012-01-01

    大流量高扬程长距离输水工程供水泵站常采用二阶段液控调节蝶阀来最大限度降低关阀水锤.小角度关阀时间长,加之常规关阀停泵的方式,通常会引起机组、管路及阀门较大的振动.从泵站实际特点出发,尽量缩短关阀时间,改变常规关阀停泵方式,有效减小了振动和噪声.%The two-stage hydraulic control butterfly valve is usually used to reduce the closing valve water hammer in the high flow rate and long distance water supply pump station, which will usually cause long closing valve time with small angle and take the conventional closing valve method to stop the pump. This method will normally cause violent vibration on pumping unit, pipeline, and valve. Rased on practical characteristics (use the principles of water-pumping and energy-saving), in this paper the valve closing time was reduced as much as possible to change conventional pump stopping method, which was proved to be able to reduce the vibration and noise.

  19. Modeling and performance evaluation of an electromechanical valve actuator for a camless IC engine

    Directory of Open Access Journals (Sweden)

    Eid Mohamed

    2012-01-01

    Full Text Available Valve train control is one of the best strategies for optimizing efficiency and emissions of Internal Combustion (IC engines. Applications of solenoid valve actuators in (IC engines can facilitate operations such as variable valve timing and variable valve lifting for improved the engine performance, fuel economy and reduce emission, the electromechanical valve actuator (EMVA uses solenoid to actuate valve movement independently for the application of (IC engine. In this work presents the effects of design and operating parameters on the system dynamic performances of the actuator and the proposed an (EMVA structure by incorporating the hybrid magneto-motive force (MMF implementation in which the magnetic flux is combined by the coil excitation and permanent magnets. A two-degree-of-freedom lumped parameter model is used to simulate the response of valve actuator system in the opening and closing. The model and control of an electromagnetic valve (EMV are described. This is done using electromagnetic force to open and close the valve and a controller regulates the motion specifications required. The developments controller is based on a state-space description of the actuator that is derived based on physical principles and parameter identification. Linear-quadratic regulator design (LQR optimal control is designed with the evaluation reasonable the performance and energy of (EMV valve are obtained with the design.

  20. Modeling and performance evaluation of an electromechanical valve actuator for a camless IC engine

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, Eid [Automotive and Tractors Engineering, Faculty of Engineering, Helwan University, Cairo (Egypt)

    2012-07-01

    Valve train control is one of the best strategies for optimizing efficiency and emissions of Internal Combustion (IC) engines. Applications of solenoid valve actuators in (IC) engines can facilitate operations such as variable valve timing and variable valve lifting for improved the engine performance, fuel economy and reduce emission, the electromechanical valve actuator (EMVA) uses solenoid to actuate valve movement independently for the application of (IC) engine. In this work presents the effects of design and operating parameters on the system dynamic performances of the actuator and the proposed an (EMVA) structure by incorporating the hybrid magneto-motive force (MMF) implementation in which the magnetic flux is combined by the coil excitation and permanent magnets. A two-degree-of-freedom lumped parameter model is used to simulate the response of valve actuator system in the opening and closing. The model and control of an electromagnetic valve (EMV) are described. This is done using electromagnetic force to open and close the valve and a controller regulates the motion specifications required. The developments controller is based on a state-space description of the actuator that is derived based on physical principles and parameter identification. Linear-quadratic regulator design (LQR) optimal control is designed with the evaluation reasonable the performance and energy of (EMV) valve are obtained with the design.

  1. Percutaneous tricuspid valve replacement in childhood

    Directory of Open Access Journals (Sweden)

    Mathias Emmel

    2015-01-01

    Full Text Available Percutaneous replacement of the tricuspid valve with a bovine jugular venous valve (melody valve was successfully undertaken in a 9-year-old boy. The patient had a previous history of bacterial endocarditis of the native tricuspid valve in infancy. Initially, a pericardial patch valve was created, followed by surgical replacement of the valve using a biological tissue valve at 4 years of age. Progressive stenosis and regurgitation of the biological valve, with severe venous congestion and resulting hepatic dysfunction prompted percutaneous valve replacement.

  2. Tricuspid Valve Replacement, Mechnical vs. Biological Valve, Which Is Better?

    Directory of Open Access Journals (Sweden)

    Haitham Akram Altaani

    2013-06-01

    Full Text Available Background: The initial trial in tricuspid surgery is repair; however, replacement is done whenever the valve is badly diseased. Tricuspid valve replacement comprises 1.7% of all tricuspid valve surgeries. Materials and Methods: The present retrospective study was performed using the medical records of 21 cases who underwent tricuspid valve replacement from January 2002 until the end of December 2010. The mean age of the participants was 52.3±8.8 years and 66.7% were females. In addition, tricuspid valve replacement was associated with mitral valve surgery, aortic valve surgery, and both in 14.3%, 4.8%, and 33.3% of the cases, respectively. Yet, isolated tricuspid valve replacement and redo surgery were performed in 10 cases (47.6% and 8 cases (38.1%, respectively. Besides, trial of repair was done in 14 cases (66.7%. Moreover, biological and mechanical valves were used in 76.2% and 23.8% of the patients, respectively. Results: According to the results, early mortality was 23.8% and one year survival was 66.7%. Moreover, early mortality was caused by right ventricular failure, multiorgan failure, medistinitis, and intracerbral bleeding in 42%, 28.6%, 14.3%, and 14.3% of the cases, respectively. In addition, 57.1% of the deaths had occurred in the cases where the biological valve was used, while 42.9% of the deaths had taken place where the mechanical one was utilized. Conclusions: The patients who require tricuspid valve replacement are usually high risk surgical candidates with early and long term mortality. The findings of the current study showed no significant hemodynamic difference between mechanical and biological valves.

  3. Transcatheter Replacement of Failed Bioprosthetic Valves

    DEFF Research Database (Denmark)

    Simonato, Matheus; Webb, John; Kornowski, Ran

    2016-01-01

    Background-Transcatheter valve implantation inside failed bioprosthetic surgical valves (valve-in-valve [ViV]) may offer an advantage over reoperation. Supra-annular transcatheter valve position may be advantageous in achieving better hemodynamics after ViV. Our objective was to define targets fo...

  4. Performance Characteristics of an Isothermal Freeze Valve

    Energy Technology Data Exchange (ETDEWEB)

    Hailey, A.E.

    2001-08-22

    This document discusses performance characteristics of an isothermal freeze valve. A freeze valve has been specified for draining the DWPF melter at the end of its lifetime. Two freeze valve designs have been evaluated on the Small Cylindrical Melter-2 (SCM-2). In order to size the DWPF freeze valve, the basic principles governing freeze valve behavior need to be identified and understood.

  5. "Vanishing" pulmonary valve stenosis

    Directory of Open Access Journals (Sweden)

    Nofil I Arain

    2012-01-01

    Full Text Available Objective: Both spontaneous resolution and progression of mild pulmonary valve stenosis (PS have been reported. We reviewed characteristics of the pulmonary valve (PV to determine factors that could influence resolution of mild PS. Methods: Fifteen asymptomatic pediatric patients with spontaneous resolution of isolated mild PS were retrospectively reviewed. Results: There was no correlation between the PV gradient, clinical presentation, age at diagnosis, or PV morphology. The PV annulus was small at initial presentation, which normalized at follow up. When corrected for the body surface area (z-score, the PV annulus was normal in all patients, including at initial evaluation. Conclusions: Based on our observation, neither age at diagnosis, nor PV-morphology-influenced resolution of mild PS. The variable clinical presentation makes it difficult to categorize and observe mild PS by auscultation alone. The PV annulus z-score could be a useful adjunct to determine the course and serial observation of mild PS.

  6. Numerical Analysis of Combined Valve Hydrodynamic Characteristics for Turbine System

    Energy Technology Data Exchange (ETDEWEB)

    Bhowmik, P. K.; Shamim, J. A.; Gairola, A.; Arif, M.; Suh, Kune Y. [Seoul National Univ., Seoul (Korea, Republic of)

    2014-05-15

    Flow characteristic curves are plotted by calculating the ratio of the measured mass flow rate versus the theoretical mass flow rate. The flow characteristic curves are utilized to accurately test the performance of the control valve of turbine system to ensure the highest controllability and reliability of the power conversion system of large and small power plants. Turbine converts the kinetic energy of steam to mechanical energy of rotor blades in power conversion system. The electrical energy output from the generator of which the rotor is coupled with that of the turbine depends on the rotation velocity of the turbine bucket. The rotation velocity is proportional to the mass flow rate (steam or gas) to the turbine through valves and nozzles. The turbine comprises fast acting governing control valves and stop valves acting against the seat in the flow passage in the closed position. The turbine control valve regulates the mass flow rate entering the first nozzle of a turbine. The main function of stop valve is to close the fluid inlet rapidly in response to a fast close signal to swiftly cut off the flow through the valve inlet. Both these valves contribute attractively to improvement of the power system transient stability as well. To improve the efficiency of power conversion system many investigation have been done by researcher by focusing on the cycle layout or working fluid or by improving the flow path of the working fluid. The main focus is to find out the best option for combined cycle power plant by analyzing four different cycle configuration. Next research phase focused on different way to enhance the cycle efficiency. As the electrical power output from the generator is proportional to the mass flow rate to the turbine through the valve, it should preferably operate linearly. In reality, however, the valve has the various flow characteristics pursuant to the stem lift. Thus, the flow characteristic and control performance are needed to be designed

  7. 总线型伺服阀在装车站液压及控制系统中的应用%Application of Bus-type Servo Valve in Hydraulic and Control System of Loading Station

    Institute of Scientific and Technical Information of China (English)

    姚志星; 张康

    2011-01-01

    In view of problems of frequent faults and low integration degree existed in traditional hydraulic and control system of loading station , the paper proposed a design scheme of hydraulic and control system of loading station based on bus-type servo valve. It gave hardware structure of the system and introduced software design in details, namely parameters setting of servo valve, configuration of industrial gateway and integration between industrial gateway and PLC. The actual application showed that the system runs stably and reliably, which meets requirements ol coal transportation.%针对传统的装车站液压及控制系统存在故障多、集成化程度低的问题,提出了一种基于总线型伺服阀的装车站液压及控制系统的设计方案;给出了该系统的硬件结构,详细介绍了该系统的软件设计,即伺服阀参数设置、工业网关配置及工业网关与PLC系统的集成.实际应用表明,该系统运行稳定、可靠,满足了煤炭运输的需求.

  8. Transcatheter aortic valve implantation in failed bioprosthetic surgical valves

    DEFF Research Database (Denmark)

    Dvir, Danny; Webb, John G; Bleiziffer, Sabine

    2014-01-01

    IMPORTANCE: Owing to a considerable shift toward bioprosthesis implantation rather than mechanical valves, it is expected that patients will increasingly present with degenerated bioprostheses in the next few years. Transcatheter aortic valve-in-valve implantation is a less invasive approach......, stroke, and New York Heart Association functional class. RESULTS: Modes of bioprosthesis failure were stenosis (n = 181 [39.4%]), regurgitation (n = 139 [30.3%]), and combined (n = 139 [30.3%]). The stenosis group had a higher percentage of small valves (37% vs 20.9% and 26.6% in the regurgitation...

  9. Minimally Invasive Mitral Valve Replacement and Transfemoral Aortic Valve Implantation.

    Science.gov (United States)

    Rustenbach, Christian; Baumbach, Hardy; Hill, Stephan; Franke, Ulrich F W

    2015-01-01

    The case is reported of a symptomatic elderly patient with severe mitral regurgitation, severe aortic valve stenosis, and coronary heart disease. The coronary artery disease had been interventionally treated four years previously with stent implantation into the right coronary artery. Published studies have shown that a combination of mitral and aortic valve surgery is associated with a significantly increased risk of mortality and morbidity, particularly in elderly patients. In the present patient, both valvular malformations were successfully treated with a single-step interdisciplinary approach, namely an initial surgical mitral valve replacement followed by transfemoral transcatheter aortic valve replacement.

  10. Research on the closure law of hydraulic control slow closing butterfly valve in pressure flow water diversion system%压力流输水系统中缓闭式液控蝶阀关闭规律研究

    Institute of Scientific and Technical Information of China (English)

    刘奕朗; 高学平; 蒋琳琳

    2012-01-01

    Water diversion system of long - distance and high - lift pressure flow will produce serious damage once pump - stopping water hammer takes place. It is a simple and effective water hammer protection measure to set one hydraulic control slow closing butterfly valve at the outlet of pump with appropriate closure way. The thesis, combining practical engineering, solve the water hammer basic equations by the method of characteristics, compare the results of different valve closure way, including the envelope line of piezometric head, pressure change at outlet of pump station and rotate speed change, then proposes the appropriate way of valve closure. The results can provide a reference for the setting of pump - stopping water hammer protective measures.%对于长距离、高扬程压力流输水系统,一旦发生停泵水锤,将对输水系统产生严重危害.在泵出口设置缓闭式液控蝶阀并以适当的方式关阀是一种简单有效的水锤防护措施.本文结合实际工程,通过特征线法求解水锤基本方程,比较不同关阀方式下管路沿程压力变化、泵站出口断面压力变化及水泵转速变化,提出合适的关阀方式.研究成果可为停泵水锤防护措施的设置提供参考.

  11. Anterior Urethral Valves

    Directory of Open Access Journals (Sweden)

    Vidyadhar P. Mali

    2006-07-01

    Full Text Available We studied the clinical presentation and management of four patients with anterior urethral valves; a rare cause of urethral obstruction in male children. One patient presented antenatally with oligohydramnios, bilateral hydronephrosis and bladder thickening suggestive of an infravesical obstruction. Two other patients presented postnatally at 1 and 2 years of age, respectively, with poor stream of urine since birth. The fourth patient presented at 9 years with frequency and dysuria. Diagnosis was established on either micturating cystourethrogram (MCU (in 2 or on cystoscopy (in 2. All patients had cystoscopic ablation of the valves. One patient developed a postablation stricture that was resected with an end-to-end urethroplasty. He had an associated bilateral vesicoureteric junction (VUJ obstruction for which a bilateral ureteric reimplantation was done at the same time. On long-term follow-up, all patients demonstrated a good stream of urine. The renal function is normal. Patients are continent and free of urinary infections. Anterior urethral valves are rare obstructive lesions in male children. The degree of obstruction is variable, and so they may present with mild micturition difficulty or severe obstruction with hydroureteronephrosis and renal impairment. Hence, it is important to evaluate the anterior urethra in any male child with suspected infravesical obstruction. The diagnosis is established by MCU or cystoscopy and the treatment is always surgical, either a transurethral ablation or an open resection. The long-term prognosis is good.

  12. Posterior Urethral Valves

    Directory of Open Access Journals (Sweden)

    Steve J. Hodges

    2009-01-01

    Full Text Available The most common cause of lower urinary tract obstruction in male infants is posterior urethral valves. Although the incidence has remained stable, the neonatal mortality for this disorder has improved due to early diagnosis and intensive neonatal care, thanks in part to the widespread use of prenatal ultrasound evaluations. In fact, the most common reason for the diagnosis of posterior urethral valves presently is the evaluation of infants for prenatal hydronephrosis. Since these children are often diagnosed early, the urethral obstruction can be alleviated rapidly through catheter insertion and eventual surgery, and their metabolic derangements can be normalized without delay, avoiding preventable infant mortality. Of the children that survive, however, early diagnosis has not had much effect on their long-term prognosis, as 30% still develop renal insufficiency before adolescence. A better understanding of the exact cause of the congenital obstruction of the male posterior urethra, prevention of postnatal bladder and renal injury, and the development of safe methods to treat urethral obstruction prenatally (and thereby avoiding the bladder and renal damage due to obstructive uropathy are the goals for the care of children with posterior urethral valves[1].

  13. Supramolecular spin valves

    Science.gov (United States)

    Urdampilleta, M.; Klyatskaya, S.; Cleuziou, J.-P.; Ruben, M.; Wernsdorfer, W.

    2011-07-01

    Magnetic molecules are potential building blocks for the design of spintronic devices. Moreover, molecular materials enable the combination of bottom-up processing techniques, for example with conventional top-down nanofabrication. The development of solid-state spintronic devices based on the giant magnetoresistance, tunnel magnetoresistance and spin-valve effects has revolutionized magnetic memory applications. Recently, a significant improvement of the spin-relaxation time has been observed in organic semiconductor tunnel junctions, single non-magnetic molecules coupled to magnetic electrodes have shown giant magnetoresistance and hybrid devices exploiting the quantum tunnelling properties of single-molecule magnets have been proposed. Herein, we present an original spin-valve device in which a non-magnetic molecular quantum dot, made of a single-walled carbon nanotube contacted with non-magnetic electrodes, is laterally coupled through supramolecular interactions to TbPc2 single-molecule magnets (Pc=phthalocyanine). Their localized magnetic moments lead to a magnetic field dependence of the electrical transport through the single-walled carbon nanotube, resulting in magnetoresistance ratios up to 300% at temperatures less than 1 K. We thus demonstrate the functionality of a supramolecular spin valve without magnetic leads. Our results open up prospects of new spintronic devices with quantum properties.

  14. 液压比例控制系统在液压支架用安全阀试验台上的应用%Application of Hydraulic Proportional Control System in Hydraulic Safety Valve Test Table

    Institute of Scientific and Technical Information of China (English)

    马强

    2013-01-01

    针对原液压支架用安全阀试验台流量调节过程繁琐、效率及检测精度低的问题,采用比例控制技术,进行闭环流量控制.改进了试验台的液压系统,实现了流量调节的自动化,提高了试验效率及检测精度.%There are problems existing in the original hydraulic safety valve test bench,including complicated flow controlling process and low accuracy and detection efficiency.To solve the problems,the proportional control technology was used to realize closed-loop flow control.The hydraulic system of the experiment platform was improved.The automation of flow regulation is realized,and the test efficiency and accuracy are improved.

  15. Flow characteristics and performance evaluation of butterfly valves using numerical analysis

    Science.gov (United States)

    Jeon, S. Y.; Yoon, J. Y.; Shin, M. S.

    2010-08-01

    The industrial butterfly valves have been applied to various fields that transport fluid in volume, especially water supply and drainage pipeline for flow control. The butterfly valves in various shapes are manufactured, but a fitting performance comparison is not made up. For this reason, we carried out numerical analysis of some kind of butterfly valves for water supply and drainage pipeline using commercial CFD code FLUENT, and made a comparative study of these results. Also, the flow coefficient, the loss coefficient, and pressure distribution of valves according to valve opening rate were compared each other and the influence of these design variables on valve performance were checked over. Through flow around the valve disk, such as pressure distribution, flow pattern, velocity vectors, and form of vortex, we grasped flow characteristics.

  16. Practical tips and tricks for assessing prosthetic valves and detecting paravalvular regurgitation using cardiac CT.

    Science.gov (United States)

    O'Neill, Ailbhe C; Martos, Ramon; Murtagh, Gillian; Ryan, Edmund Ronan; McCreery, Charles; Keane, David; Quinn, Martin; Dodd, Jonathan D

    2014-01-01

    Paravalvular leaks are an uncommon but serious complication of prosthetic valves. Transthoracic echocardiography is used in the assessment of prosthetic valves but can be limited by acoustic shadowing from the prosthesis and poor acoustic windowing. Small case series have previously shown cardiac CT to have promising results in detecting paravalvular leaks. We assessed 32 valves in our institution on cardiac CT using echocardiography results as standard and developed methods for improved evaluation of prosthetic valves. These include optimizing prescan drug therapy for heart rate control, optimum window and center adjustments, and carefully selected image planes to best demonstrate the valve ring and valve annulus. Recognition of surgical material is also important to recognize. In this review, we provide a detailed description of these techniques with imaging examples of prosthetic valve evaluation using cardiac CT. Copyright © 2014 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

  17. Giant magnetoresistance in organic spin-valves.

    Science.gov (United States)

    Xiong, Z H; Wu, Di; Vardeny, Z Valy; Shi, Jing

    2004-02-26

    A spin valve is a layered structure of magnetic and non-magnetic (spacer) materials whose electrical resistance depends on the spin state of electrons passing through the device and so can be controlled by an external magnetic field. The discoveries of giant magnetoresistance and tunnelling magnetoresistance in metallic spin valves have revolutionized applications such as magnetic recording and memory, and launched the new field of spin electronics--'spintronics'. Intense research efforts are now devoted to extending these spin-dependent effects to semiconductor materials. But while there have been noteworthy advances in spin injection and detection using inorganic semiconductors, spin-valve devices with semiconducting spacers have not yet been demonstrated. pi-conjugated organic semiconductors may offer a promising alternative approach to semiconductor spintronics, by virtue of their relatively strong electron-phonon coupling and large spin coherence. Here we report the injection, transport and detection of spin-polarized carriers using an organic semiconductor as the spacer layer in a spin-valve structure, yielding low-temperature giant magnetoresistance effects as large as 40 per cent.

  18. Nitrile/Buna N Material Failure Assessment for an O-Ring used on the Gaseous Hydrogen Flow Control Valve (FCV) of the Space Shuttle Main Engine

    Science.gov (United States)

    Wingard, Doug

    2006-01-01

    After the rollout of Space Shuttle Discovery in April 2005 in preparation for return-to-flight, there was a failure of the Orbiter (OV-103) helium signature leak test in the gaseous hydrogen (GH2) system. Leakage was attributed to the Flow Control Valve (FCV) in Main Engine 3. The FCV determined to be the source of the leak for OV-103 is designated as LV-58. The nitrile/Buna N rubber O-ring seal was removed from LV-58, and failure analysis indicated radial cracks providing leak paths in one quadrant. Cracks were eventually found in 6 of 9 FCV O-rings among the three Shuttle Orbiters, though none were as severe as those for LV-58, OV-103. Testing by EM10 at MSFC on all 9 FCV O- rings included: laser dimensional, Shore A hardness and properties from a dynamic mechanical analyzer (DMA) and an Instron tensile machine. The following test data was obtained on the cracked quadrant of the LV-58, OV-103 O-ring: (1) the estimated compression set was only 9.5%, compared to none for the rest of the O-ring; (2) Shore A hardness for the O.D. was higher by almost 4 durometer points than for the rest of the O-ring; and (3) DMA data showed that the storage/elastic modulus E was almost 25% lower than for the rest of the O-ring. Of the 8 FCV O-rings tested on an Instron, 4 yielded tensile strengths that were below the MIL spec requirement of 1350 psi-a likely influence of rubber cracking. Comparisons were made between values of modulus determined by DNA (elastic) and Instron (Young s). Each nitrile/Buna N O-ring used in the FCV conforms to the MIL-P-25732C specification. A number of such O-rings taken from shelf storage at MSFC and Kennedy Space Center (KSC) were used to generate a reference curve of DMA glass transition temperature (Tg) vs. shelf storage time ranging from 8 to 26 years. A similar reference curve of TGA onset temperature (of rubber weight loss) vs. shelf storage time was also generated. The DMA and TGA data for the used FCV O-rings were compared to the reference

  19. 可变气门正时机构特殊模式控制策略的仿真研究%Simulative study of control strategy of special modes for the mechanism of variable valve timing

    Institute of Scientific and Technical Information of China (English)

    张晓松; 滕勤; 李杰

    2016-01-01

    针对发动机可变气门正时(variable valve timing ,VVT )控制系统凸轮轴调节过程中可能出现的特殊工作模式 ,文章建立了相应的控制策略 ,并计算对应的凸轮轴目标相位 . 当机油温度过高 、发动机转速下降太快导致机油压力降低时 ,为了防止凸轮轴调节速度明显降低 ,提出停调排气凸轮轴的控制策略 ;为了预防发动机工作中产生的碎屑阻塞相位器和机油控制阀 ,提出预防性清洗策略 ;根据这 2 种控制策略对凸轮轴调节效果的影响 ,对其进行了优先级划分 . 在 ASCET-MD 环境中建立了控制模型 ,通过仿真实验验证了控制逻辑 ,结果表明 ,凸轮轴目标位置完全适合相应的控制策略 .%For some special operating modes that may occur during the adjustment of camshaft in the engine with variable valve timing (VVT ) ,the corresponding control systems are established and the corresponding target positions are calculated .Low oil pressure may occur when the oil temperature is too high and the engine speed drops too quickly ,and in order to prevent the adjustment rate of cam-shaft dropping too significantly ,the strategy of stopping the adjustment of exhaust camshaft is estab-lished ;in order to prevent the dirt deposits generated in the engine blocking the camshaft phaser and oil control valve ,the strategy of preventive cleaning is established ;then the two control strategies are prioritized based on their effects on the adjustment of camshaft .Finally ,the models of control sys-tems are established and some simulation experiments are done in ASCET-MD .The experimental re-sults verify the control logic and indicate that the target positions of camshaft are completely fit for the corresponding control strategy .

  20. Valve stem and packing assembly

    Energy Technology Data Exchange (ETDEWEB)

    Wordin, J.J.

    1991-09-03

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents over tightening of the retaining nut and the resulting excessive friction between stem and stem packing. 2 figures.

  1. Valve stem and packing assembly

    Energy Technology Data Exchange (ETDEWEB)

    Wordin, John J. (Bingham County, ID)

    1991-01-01

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

  2. Valve stem and packing assembly

    Energy Technology Data Exchange (ETDEWEB)

    Wordin, J.J.

    1990-01-01

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

  3. Second-generation transapical valves: the Medtronic Engager system.

    Science.gov (United States)

    Sündermann, Simon H; Holzhey, David; Bleiziffer, Sabine; Treede, Hendrik; Jacobs, Stephan; Falk, Volkmar

    2014-01-01

    The Medtronic Engager aortic valve system is a second-generation transcatheter aortic valve implantation bioprosthesis combined with a delivery system designed for over-the-wire transapical implantation of the valve. The self-expandable stent has control arms to be placed into the native aortic sinuses to achieve correct positioning of the bioprosthesis in a predefined height. The purpose of the lower skirt is to reduce paravalvular leakage. A three-leaflet, bovine pericardium valve is mounted on the stent. The implantation is facilitated by the control arms and rotational positioning of the commissural posts. A multicentre feasibility study showed promising results. The results from the following European pivotal trial led to CE mark approval in 2013. Here, we describe technical details of the device and its implantation technique and highlight special steps of the procedure.

  4. New design method for valves internals, to optimize process

    Energy Technology Data Exchange (ETDEWEB)

    Jorge, Leonardo [PDVSA (Venezuela)

    2011-07-01

    In the heavy oil industry, various methods can be used to reduce the viscosity of oil, one of them being the injection of diluent. This method is commonly used in the Orinoco oil belt but it requires good control of the volume of diluent injected as well as the gas flow to optimize production; thus flow control valves need to be accurate. A new valve with a new method was designed with the characteristic of being very reliable and was then bench tested and compared with the other commercially available valves. Results showed better repeatability, accuracy and reliability with lower maintenance for the new method. The use of this valve provides significant savings while distributing the exact amount of fluids; up to date a less than 2% failure rate has been recorded in the field. The new method developed demonstrated impressive performance and PDVSA has decided to use it in mass.

  5. File list: InP.CDV.20.AllAg.Aortic_valve_endothelial_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.CDV.20.AllAg.Aortic_valve_endothelial_cells hg19 Input control Cardiovascular Aortic valve endothe...lial cells SRX285598 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.CDV.20.AllAg.Aortic_valve_endothelial_cells.bed ...

  6. File list: InP.CDV.05.AllAg.Aortic_valve_endothelial_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.CDV.05.AllAg.Aortic_valve_endothelial_cells hg19 Input control Cardiovascular Aortic valve endothelial... cells SRX285598 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.CDV.05.AllAg.Aortic_valve_endothelial_cells.bed ...

  7. File list: InP.CDV.50.AllAg.Aortic_valve_endothelial_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.CDV.50.AllAg.Aortic_valve_endothelial_cells hg19 Input control Cardiovascular Aortic valve endothelial... cells SRX285598 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.CDV.50.AllAg.Aortic_valve_endothelial_cells.bed ...

  8. File list: InP.CDV.10.AllAg.Aortic_valve_endothelial_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.CDV.10.AllAg.Aortic_valve_endothelial_cells hg19 Input control Cardiovascular Aortic valve endothelial... cells SRX285598 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.CDV.10.AllAg.Aortic_valve_endothelial_cells.bed ...

  9. Mitral Valve Prolapse in Pregnancy

    Directory of Open Access Journals (Sweden)

    Shi-Min Yuan

    Full Text Available Abstract Mitral valve prolapse is a benign condition. Mitral regurgitation is only complicated in patients with severe mitral valve prolapse. Women with mitral valve prolapse in the absence of other cardiovascular disorders tolerate pregnancy well and do not develop remarkable cardiac complications. Nevertheless, serious complications of mitral valve prolapse, including arrhythmia, infective endocarditis and cerebral ischemic events, can be present in pregnancy. Debates remain with regard to the use of prophylactic antibiotics and β-blockers in the pregnant women with mitral valve prolapse. The prognosis of the pregnant patients might be closely related to the pathological and (or functional changes of the mitral valve. Non-myxomatous mitral valve prolapse poses no or little obstetric risks in terms of pregnancy, labor and neonatal complications; whereas myxomatous mitral valve prolapse is a major etiology of valvular heart disease in women of childbearing age. In the pregnant patients with mitral valve prolapse progressing into major complications, surgical interventions are considered. Medicinal treatment of such patients with β-blockers should be a concern for the fetal safety.

  10. Innovative Stemless Valve Eliminates Emissions

    Science.gov (United States)

    2008-01-01

    Big Horn Valve Inc. (BHVI), of Sheridan, Wyoming, won a series of SBIR and Small Business Technology Transfer (STTR) contracts with Kennedy Space Center and Marshall Space Flight Center to explore and develop a revolutionary valve technology. BHVI developed a low-mass, high-efficiency, leak-proof cryogenic valve using composites and exotic metals, and had no stem-actuator, few moving parts, with an overall cylindrical shape. The valve has been installed at a methane coal gas field, and future applications are expected to include in-flight refueling of military aircraft, high-volume gas delivery systems, petroleum refining, and in the nuclear industry.

  11. An air-pressure-free elastomeric valve for integrated nucleic acid analysis by capillary electrophoresis

    Science.gov (United States)

    Jung, Wooseok; Barrett, Matthew; Brooks, Carla; Rivera, Andrew; Birdsell, Dawn N.; Wagner, David M.; Zenhausern, Frederic

    2015-12-01

    We present a new elastomeric valve for integrated nucleic acid analysis by capillary electrophoresis. The valve functions include metering to capture a designated volume of biological sample into a polymerase chain reaction (PCR) chamber, sealing to preserve the sample during PCR cycling, and transfer of the PCR-products and on-chip formamide post-processing for the analysis of DNA fragments by capillary gel electrophoresis. This new valve differs from prior art polydimethylsiloxane (PDMS) valves in that the valve is not actuated externally by air-pressure or vacuum so that it simplifies a DNA analysis system by eliminating the need for an air-pressure or vacuum source, and off-cartridge solenoid valves, control circuit boards and software. Instead, the new valve is actuated by a thermal cycling peltier assembly integrated within the hardware instrument that tightly comes in contact with a microfluidic cartridge for thermal activation during PCR, so that it spontaneously closes the valve without an additional actuator system. The valve has bumps in the designated locations so that it has a self-alignment that does not require precise alignment of a valve actuator. Moreover, the thickness of the new valve is around 600 μm with an additional bump height of 400 μm so that it is easy to handle and very feasible to fabricate by injection molding compared to other PDMS valves whose thicknesses are around 30-100 μm. The new valve provided over 95% of metering performance in filling the fixed volume of the PCR chamber, preserved over 97% of the sample volume during PCR, and showed very comparable capillary electrophoresis peak heights to the benchtop assay tube controls with very consistent transfer volume of the PCR-product and on-chip formamide. The new valve can perform a core function for integrated nucleic acid analysis by capillary electrophoresis.

  12. Fluid and Structural Analysis of Large Butterfly Valve

    Science.gov (United States)

    Song, Xueguan; Wang, Lin; Park, Youngchul

    2008-10-01

    A butterfly valve of large diameter is commonly used as control equipments in applications where the inlet velocity is fast and the pressure is relatively high. Because of the size of the valve is too large, therefore it's too difficult to conduct the experiment in a laboratory. In this paper, the numerical simulation using commercial package-CFX and ANSYS was conducted. In order to do fluid analysis and structural analysis perfectly, large valve models are generated in three dimensions without much simplification, the result of fluid analysis is also fully coupled to the structural domain by the fluid-structural interface to provide an exacter initial condition. In addition to describe the flow patterns and to measure the performance coefficients when the valves with various open angles were used, the verification of the safety performance whether the valve could work normally at those conditions or not was conducted. Fortunately, the result shows this type valve is safe in a given inlet velocity of 3m/s, and it's not necessary to be strengthened anywhere, and if need be, the shape of valve disc can be optimized to reduce the weight of disc, and also to make the flow coefficient be closer to the suggested level.

  13. Prognostics for Ground Support Systems: Case Study on Pneumatic Valves

    Science.gov (United States)

    Daigle, Matthew; Goebel, Kai

    2011-01-01

    Prognostics technologies determine the health (or damage) state of a component or sub-system, and make end of life (EOL) and remaining useful life (RUL) predictions. Such information enables system operators to make informed maintenance decisions and streamline operational and mission-level activities. We develop a model-based prognostics methodology for pneumatic valves used in ground support equipment for cryogenic propellant loading operations. These valves are used to control the flow of propellant, so failures may have a significant impact on launch availability. Therefore, correctly predicting when valves will fail enables timely maintenance that avoids launch delays and aborts. The approach utilizes mathematical models describing the underlying physics of valve degradation, and, employing the particle filtering algorithm for joint state-parameter estimation, determines the health state of the valve and the rate of damage progression, from which EOL and RUL predictions are made. We develop a prototype user interface for valve prognostics, and demonstrate the prognostics approach using historical pneumatic valve data from the Space Shuttle refueling system.

  14. Micro system comprising 96 micro valves on a titer plate

    Science.gov (United States)

    Krabbe, S.; Flitsch, D.; Büchs, J.; Schomburg, W. K.

    2016-10-01

    A system of 96 micro valves has been developed and mounted on top of a 48-well micro titer plate providing two valves for each well controlling its air inlet and outlet. Testing of the valve system showed that all valves are working and are opened and closed reliably. A pneumatic system is switching inlet and outlet valves independently of each other. The geometry of the feed channels ensures an equal air flow through all wells, when the valves are open. Between the micro valves, one optical fibre was inserted through the lid of each well allowing measuring the oxygen partial pressure in the enclosed air volume by fluorescence sensor spots. Escherichia coli bacteria were grown inside the wells and their metabolism was observed by the oxygen partial pressure change due to respiration. In all 48 wells, the same oxygen transfer rate was observed within an averaged standard deviation of 1 mmol/L/h. The oxygen transfer rate differences compared to a macroscopic standard shake flask system were overall compatible within their uncertainties.

  15. Microfluidic droplet sorting using integrated bilayer micro-valves

    Science.gov (United States)

    Chen, Yuncong; Tian, Yang; Xu, Zhen; Wang, Xinran; Yu, Sicong; Dong, Liang

    2016-10-01

    This paper reports on a microfluidic device capable of sorting microfluidic droplets utilizing conventional bilayer pneumatic micro-valves as sorting controllers. The device consists of two micro-valves placed symmetrically on two sides of a sorting area, each on top of a branching channel at an inclined angle with respect to the main channel. Changes in transmitted light intensity, induced by varying light absorbance by each droplet, are used to divert the droplet from the sorting area into one of the three outlet channels. When no valve is activated, the droplet flows into the outlet channel in the direction of the main channel. When one of the valves is triggered, the flexible membrane of valve will first be deflected. Once the droplet leaves the detection point, the deflected membrane will immediately return to its default flattened position, thereby exerting a drawing pressure on the droplet and deviating it from its original streamline to the outlet on the same side as the valve. This sorting method will be particularly suitable for numerous large-scale integrated microfluidic systems, where pneumatic micro-valves are already used. Only few structural modifications are needed to achieve droplet sorting capabilities in these systems. Due to the mechanical nature of diverting energy applied to droplets, the proposed sorting method may induce only minimal interference to biological species or microorganisms encapsulated inside the droplets that may accompany electrical, optical and magnetic-based techniques.

  16. Slide Valves for Single-Screw Expanders Working Under Varied Operating Conditions

    Directory of Open Access Journals (Sweden)

    Yuting Wu

    2016-06-01

    Full Text Available This paper fully describes the working principle of slide valves in single-screw expanders (SSEs. A geometric analysis of suction and volume ratio slide valves is presented to determine the relations between volume ratio, suction closure volume, discharge opening volume and slide valves displacement. An organic Rankine cycle (ORC thermodynamic model with SSE integrated with slide valves is developed to analyze the power output of SSE and the net power output of ORC system and variation law of slide valves displacement. Analysis of a typical ORC system under changing operating conditions shows that the power output of the expander and the net output power of the ORC system with slide valves are much better than those without slide valves. When the condensing temperature is 40 °C and the waste availability is 80 kW, the increase in output power and net output power are approximately 3.4 kW and 5 kW, respectively. The presented geometric analysis of slide valves and the thermodynamic model integrated with slide valves can be used to provide a theoretical and technical basis for designing the slide valves of SSEs and the control strategies of slide valves under varied operating conditions.

  17. Use of One-Way Intrabronchial Valves in Air Leak Management After Tube Thoracostomy Drainage.

    Science.gov (United States)

    Gilbert, Christopher R; Casal, Roberto F; Lee, Hans J; Feller-Kopman, David; Frimpong, Bernice; Dincer, H Erhan; Podgaetz, Eitan; Benzaquen, Sadia; Majid, Adnan; Folch, Erik; Gorden, Jed A; Chenna, Praveen; Chen, Alex; Abouzgheib, Wissam; Sanny Nonyane, Bareng Aletta; Yarmus, Lonny B

    2016-05-01

    A persistent air leak represents significant clinical management problems, potentially affecting morbidity, mortality, and health care costs. In 2008, a unidirectional, intrabronchial valve received humanitarian device exemption for use in managing prolonged air leak after pulmonary resection. Since its introduction, numerous reports exist but no large series describe current utilization or outcomes. Our aim was to report current use of intrabronchial valves for air leaks and review outcome data associated with its utilization. A multicenter, retrospective review of intrabronchial valve utilization from January 2013 to August 2014 was performed at eight centers. Data regarding demographics, valve utilization, and outcomes were analyzed. We identified 112 patients undergoing evaluation for intrabronchial valve placement, with 67% (75 of 112) undergoing valve implantation. Nearly three quarters of patients underwent valve placement for off-label usage (53 of 75). A total of 195 valves were placed in 75 patients (mean 2.6 per patient; range, 1 to 8) with median time to air leak resolution of 16 days (range, 2 to 156). We present the largest, multicenter study of patients undergoing evaluation for intrabronchial valve use for air leak management. Our data suggest the majority of intrabronchial valve placements are occurring for off-label indications. Although the use of intrabronchial valves are a minimally invasive intervention for air leak management, the lack of rigorously designed studies demonstrating efficacy remains concerning. Prospective randomized controlled studies remain warranted. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  18. Whitey Gauge and Root Valves (VPS)

    Energy Technology Data Exchange (ETDEWEB)

    MISKA, C.

    2000-09-03

    These valves are 1/2 inch ball valves fabricated of 316 stainless steel: Packing is TFE (standard). They are used as isolation valves for pressure instrumentation in the Vacuum Pumping and Helium System.

  19. Evidence that an evolutionary transition from dehiscent to indehiscent fruits in Lepidium (Brassicaceae) was caused by a change in the control of valve margin identity genes.

    Science.gov (United States)

    Mühlhausen, Andreas; Lenser, Teresa; Mummenhoff, Klaus; Theißen, Günter

    2013-03-01

    In the Brassicaceae, indehiscent fruits evolved from dehiscent fruits several times independently. Here we use closely related wild species of the genus Lepidium as a model system to analyse the underlying developmental genetic mechanisms in a candidate gene approach. ALCATRAZ (ALC), INDEHISCENT (IND), SHATTERPROOF1 (SHP1) and SHATTERPROOF2 (SHP2) are known fruit developmental genes of Arabidopsis thaliana that are expressed in the fruit valve margin governing dehiscence zone formation. Comparative expression analysis by quantitative RT-PCR, Northern blot and in situ hybridization show that their orthologues from Lepidium campestre (dehiscent fruits) are similarly expressed at valve margins. In sharp contrast, expression of the respective orthologues is abolished in the corresponding tissue of indehiscent Lepidium appelianum fruits, indicating that changes in the genetic pathway identified in A. thaliana caused the transition from dehiscent to indehiscent fruits in the investigated species. As parallel mutations in different genes are quite unlikely, we conclude that the changes in gene expression patterns are probably caused by changes in upstream regulators of ALC, IND and SHP1/2, possible candidates from A. thaliana being FRUITFULL (FUL), REPLUMLESS (RPL) and APETALA2 (AP2). However, neither expression analyses nor functional tests in transgenic plants provided any evidence that the FUL or RPL orthologues of Lepidium were involved in evolution of fruit indehiscence in Lepidium. In contrast, stronger expression of AP2 in indehiscent compared to dehiscent fruits identifies AP2 as a candidate gene that deserves further investigation.

  20. The dilemma of complicated shunt valves: How to identify patients with posthemorrhagic hydrocephalus after aneurysmatic subarachnoid hemorrhage who will benefit from a simple valve?

    Directory of Open Access Journals (Sweden)

    Christian von der Brelie

    2016-01-01

    Full Text Available Background: Sophisticated shunt valves provide the possibility of pressure adjustment and antisiphon control but have a higher probability of valve dysfunction especially in a posthemorrhagic setting. The aim of the present study is to analyze the clinical outcome of patients with shunt dependent posthemorrhagic hydrocephalus after aneurysmatic subarachnoid hemorrhage (SAH in order to identify patients who would benefit from a simple differential pressure valve. Methods: From 2000 to 2013, 547 patients with aneurysmatic SAH were treated at our institution, 114 underwent ventricular shunt placement (21.1%. 47 patients with available pre- and post-operative computed tomography scans, and an available follow-up of minimum 6 months were included. In order to measure the survival time which a nonprogrammable differential pressure valve would have had in an individual patient we defined the initial equalized shunt survival time (IESS. IESS is the time until surgical revisions of fixed differential pressure or flow-regulated valves for the treatment of over- or under-drainage as well as re-programming of adjustable valves due to over- or under-drainage. Results: Twenty patients were treated with fixed differential pressure valves, 15 patients were treated with flow-regulated valves, and 12 underwent ventriculoperitoneal (VP shunt placement with differential pressure valves assisted by a gravitational unit. Patients who reacted with remarkable changes of the ventricular width after the insertion of external ventricular drainage (EVD, before shunt placement, showed a significantly longer IESS. Conclusions: Decline of the ventricular width after EVD placement was a predictor for successful VP shunt therapy in the later course of disease. Possibly, this could allow identifying patients who benefit from a simple differential pressure valve or a flow-regulated valve, and thus could possibly avoid valve-associated complications of a programmable valve in the

  1. Transcatheter Aortic Valve Replacement in Bicuspid Aortic Valve Disease

    DEFF Research Database (Denmark)

    Mylotte, Darren; Lefevre, Thierry; Søndergaard, Lars

    2014-01-01

    BACKGROUND: Limited information exists describing the results of transcatheter aortic valve (TAV) replacement in patients with bicuspid aortic valve (BAV) disease (TAV-in-BAV). OBJECTIVES: This study sought to evaluate clinical outcomes of a large cohort of patients undergoing TAV-in-BAV. METHODS...

  2. Prosthetic valve endocarditis after transcatheter aortic valve implantation

    DEFF Research Database (Denmark)

    Olsen, Niels Thue; De Backer, Ole; Thyregod, Hans G H

    2015-01-01

    risk factors. METHODS AND RESULTS: Observational single-center study of 509 consecutive patients treated with a transcatheter implanted self-expandable aortic valve prosthesis (Medtronic CoreValve). We identified 18 patients diagnosed with TAVI-PVE during a median follow-up period of 1.4 years...

  3. High Reliability Cryogenic Piezoelectric Valve Actuator Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cryogenic fluid valves are subject to harsh exposure and actuators to drive these valves require robust performance and high reliability. DSM's piezoelectric...

  4. Design and Application of Valve Controlled Speed Regulating Hydraulic Coupling in Wutongzhuang Mine%阀控调速型液力偶合器在梧桐庄矿的设计及应用

    Institute of Scientific and Technical Information of China (English)

    李永苏

    2012-01-01

    According to the design and project practices of the belt conveyor in a dip of No. 4 mining block in Wutongzhuang Mine, the paper had a discussion on the factors considered in the driving method selection of the powerful belt conveyor under the complicated per- formances. A detail comparison and selection was conducted on the advantages and disadvantages of the CST, valve controlled speed regu- lating hydraulic coupling and frequency converted control soft driving modes available applied at home and abroad. The paper held that the valve controlled speed regulating hydraulic coupling could meet the driving requirements of the large power, long distance and complicated belt conveyor. The practices showed that the control start accelerated speed, start torque, automatic power balance, heat radiation and others were excellent.%根据对梧桐庄矿四采区下山带式输送机的设计和工程实践,探讨了复杂工况下强力带式输送机驱动方式选择时应考虑的因素;对现阶段国内外主要使用的CST、阀控调速型液力偶合器、变频调速3种软驱动方式的优缺点进行了详细比选;认为阀控调速型液力偶合器可以满足大功率、长距离、复杂带式输送机驱动要求,实践证明其在控制启动加速度和启动力矩、自动功率平衡、散热等方面表现优良。

  5. Design of Closed-loop Control System for Electronic Throttle Valve Based on LabVIEW%基于LabVIEW的电子节气门开度闭环控制系统设计

    Institute of Scientific and Technical Information of China (English)

    蒋艳; 钱伟康; 倪元鸿

    2012-01-01

    设计了基于LabVIEW 2010平台实现对汽车电子节气门蝶阀开度的闭环控制系统.系统选用NI的高速M系列USB-6251数据采集板卡采集从节气门位置传感器反馈的电压信号,且输出两路互补PWM信号控制节气门体中的直流电机.结合PID积分分离控制算法,即当节气门蝶阀开度变化较小时采用PID算法,当角度变化较大时采用PD算法.实验证明系统编程简单,人机交互方便,开发周期短,闭环控制效果良好,具有实际的应用价值.%The paper designs the closed-loop control system for automotive electronic throttle valve opening which is based on Lab VIEW 2010 platform. System uses NI high-speed M-Series USB-6251 data acquisition board to collect feedback voltage signal from the throttle position sensor and then outputs two complementary PWM signals to control DC motor which is in throttle body. System chooses PID control algorithm with integral separation, that is to say, when the throttle valve opening change is small,system uses PID algorithm, otherwise uses PD algorithm. Experiments show that system has the advantages of simple programming, convenient human-computer interaction, short development cycles and good closed-loop control, so this research has practical value in real life.

  6. Surge-damping vacuum valve

    Science.gov (United States)

    Bullock, Jack C.; Kelly, Benjamin E.

    1980-01-01

    A valve having a mechanism for damping out flow surges in a vacuum system which utilizes a slotted spring-loaded disk positioned adjacent the valve's vacuum port. Under flow surge conditions, the differential pressure forces the disk into sealing engagement with the vacuum port, thereby restricting the flow path to the slots in the disk damping out the flow surge.

  7. Mitral valve surgery - minimally invasive

    Science.gov (United States)

    ... Saunders; 2012:chap 61. Otto CM, Bonow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ... Editorial team. Related MedlinePlus Health Topics Heart Surgery Heart Valve Diseases Mitral Valve Prolapse Browse the Encyclopedia A.D. ...

  8. Valve-"Health"-Monitoring System

    Science.gov (United States)

    Jensen, Scott L.; Drouant, George J.

    2009-01-01

    A system that includes sensors and data acquisition, wireless data-communication, and data-processing subsystems has been developed as a means of both real-time and historical tracking of information indicative of deterioration in the mechanical integrity and performance of a highgeared ball valve or a linearly actuated valve that operates at a temperature between cryogenic and ambient.

  9. A design strategy for magnetorheological dampers using porous valves

    Energy Technology Data Exchange (ETDEWEB)

    Hu, W; Robinson, R; Wereley, N M [Smart Structures Laboratory, Alfred Gessow Rotorcraft Center, Department of Aerospace Engineering, University of Maryland, College Park, MD 20742 (United States)], E-mail: wereley@umd.edu

    2009-02-01

    To design a porous-valve-based magnetorheological (MR) damper, essential design parameters are presented. The key elements affecting the damper performance are identified using flow analysis in porous media and an empirical magnetic field distribution in the porous valve. Based on a known MR fluid, the relationship between the controllable force of the damper and the porous valve characteristics, i.e. porosity and tortuosity, is developed. The effect of the porosity and tortuosity on the field-off damping force is exploited by using semi-empirical flow analysis. The critical flow rate for the onset of nonlinear viscous damping force is determined. Using the above design elements, an MR damper using by-pass porous valve is designed and tested. The experimental damper force and equivalent damping are compared with the predicted results to validate this design strategy.

  10. Flow Characterization of a Piezo-Electric High Speed Valve

    Directory of Open Access Journals (Sweden)

    T. Takiya

    2012-03-01

    Full Text Available Injecting a gas into fusion reactors or semiconductor manufacturing systems, one has to quickly control the flow rate by a piezoelectric valve. In order to construct a gas injection system with high speed valves in the future, performance tests have been conducted on a commercial piezoelectric valve. An orifice flowmeter for measuring time average flowrate and a hot wire anemometer for instantaneous flowrate were manufactured. The total flow coefficient of the orifice flowmeter was obtained experimentally under a low pressure of a 10-2 Pa and a low flowrate of a few mg/s, although they are smaller than the values specified by Japanese Industrial Standards. It is found that the hot wire anemometer installed downstream in the vicinity of the valve is suitable for detecting the change in flowrate with the response time of less than 1 ms.

  11. Update to the study protocol, including statistical analysis plan for a randomized clinical trial comparing comprehensive cardiac rehabilitation after heart valve surgery with control

    DEFF Research Database (Denmark)

    Sibilitz, Kirstine Laerum; Berg, Selina Kikkenborg; Hansen, Tina Birgitte

    2015-01-01

    -benefit will be assessed. A mixed-method design will be used to evaluate qualitative and quantitative findings, encompassing a survey-based study before the trial and a qualitative pre- and post-intervention study. CONCLUSION: This randomized clinical trial will contribute with evidence of whether cardiac rehabilitation...... (VO2 peak) measured by cardiopulmonary exercise testing with ventilatory gas analysis. The secondary outcome is self-assessed mental health measured by the standardized questionnaire Short Form-36. Long-term healthcare utilization and mortality as well as biochemistry, echocardiography and cost...... should be provided after heart valve surgery. The study is approved by the local regional Research Ethics Committee (H-1-2011-157), and the Danish Data Protection Agency (j.nr. 2007-58-0015). TRIAL REGISTRATION: Trial registered 16 March 2012; ClinicalTrials.gov ( NCT01558765 )....

  12. New Seat Design and Finite Element Analysis for Anti-Leakage of Globe Valve

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sung Ho [Sunlin College, Pohang (Korea, Republic of); Kang, Gyeong Ah; Kwak, Jae Seob; An, Jun Eun; Jin, Dong Hyun [Pukyong National Univ., Daejeon (Korea, Republic of)

    2016-01-15

    The valves used to control or shut off the flow through a pipeline can be divided into many different types, including gate valves, globe valves, and check valves. Globe valves, in particular, have excellent properties, and because they can easily control the flow under high-pressure conditions, they are generally used in LNG ship and steam pipelines. In this paper, a method for changing the shape of a seat was suggested to solve the valve leakage problem from a structural perspective. In addition, the stress distribution and directional deformation were compared for each model. The suggested models were thus validated, and the optimized seat structure, which includes a self-supporting capability for decreasing the amount of leakage, was determined.

  13. Fluid mechanics of artificial heart valves.

    Science.gov (United States)

    Dasi, Lakshmi P; Simon, Helene A; Sucosky, Philippe; Yoganathan, Ajit P

    2009-02-01

    1. Artificial heart valves have been in use for over five decades to replace diseased heart valves. Since the first heart valve replacement performed with a caged-ball valve, more than 50 valve designs have been developed, differing principally in valve geometry, number of leaflets and material. To date, all artificial heart valves are plagued with complications associated with haemolysis, coagulation for mechanical heart valves and leaflet tearing for tissue-based valve prosthesis. For mechanical heart valves, these complications are believed to be associated with non-physiological blood flow patterns. 2. In the present review, we provide a bird's-eye view of fluid mechanics for the major artificial heart valve types and highlight how the engineering approach has shaped this rapidly diversifying area of research. 3. Mechanical heart valve designs have evolved significantly, with the most recent designs providing relatively superior haemodynamics with very low aerodynamic resistance. However, high shearing of blood cells and platelets still pose significant design challenges and patients must undergo life-long anticoagulation therapy. Bioprosthetic or tissue valves do not require anticoagulants due to their distinct similarity to the native valve geometry and haemodynamics, but many of these valves fail structurally within the first 10-15 years of implantation. 4. These shortcomings have directed present and future research in three main directions in attempts to design superior artificial valves: (i) engineering living tissue heart valves; (ii) development of advanced computational tools; and (iii) blood experiments to establish the link between flow and blood damage.

  14. Cavitation detection of butterfly valve using support vector machines

    Science.gov (United States)

    Yang, Bo-Suk; Hwang, Won-Woo; Ko, Myung-Han; Lee, Soo-Jong

    2005-10-01

    Butterfly valves are popularly used in service in the industrial and water works pipeline systems with large diameter because of its lightweight, simple structure and the rapidity of its manipulation. Sometimes cavitation can occur, resulting in noise, vibration and rapid deterioration of the valve trim, and do not allow further operation. Thus, monitoring of cavitation is of economic interest and is very important in industry. This paper proposes a condition monitoring scheme using statistical feature evaluation and support vector machine (SVM) to detect the cavitation conditions of butterfly valve which used as a flow control valve at the pumping stations. The stationary features of vibration signals are extracted from statistical moments. The SVMs are trained, and then classify normal and cavitation conditions of control valves. The SVMs with the reorganized feature vectors can distinguish the class of the untrained and untested data. The classification validity of this method is examined by various signals acquired from butterfly valves in the pumping stations. And the classification success rate is compared with that of self-organizing feature map neural network (SOFM).

  15. Optimising BMW four-cylinder two-valve engines Optimising BMW Four-Cylinder Two-Valve Engines (OpOptimising BMW Four-Cylinder Two-Valve Engines (OpOptimising BMW Four-Cylinder Two-Valve Engines (OpOptimising BMW Four-Cylinder Two-Valve Engines (OpOptimising BMW Four-Cylinder Two-Valve Engines (OpOptimising BMW Four-Cylinder Two-Valve Engines (OpOptimising BMW Four-Cylinder Two-Valve Engines (OpOptimising BMW Four-Cylinder Two-Valve Engines (OpOptimising BMW Four-Cylinder Two-Valve Engines (OpOpt

    Science.gov (United States)

    Flierl, R.; Kramer, F.; Rech, H.; Stanski, U.; Wenzel, M.

    1993-11-01

    In model year 1994, BMW will present two essentially redesigned 4-cylinder, 2-valve engines. BMW has upgraded its 1.6 1 and 1.8 1 2-valve engines using technical features previously reserved for the 4-valve engines, such as knock control system, distributorless semiconductor ignition, variable induction system (DISA) and ribbed V-belt accessory drive, along with measures to reduce power losses, noise levels and exhaust emissions. BMW models equipped with these two engines offer customers improved response characteristics and fuel consumption, as well as reduced emissions and maintenance requirements.

  16. Robotic mitral valve surgery.

    Science.gov (United States)

    Kypson, Alan P; Nifong, L Wiley; Chitwood, W Randolph

    2003-12-01

    A renaissance in cardiac surgery has begun. The early clinical experience with computer-enhanced telemanipulation systems outlines the limitations of this approach despite some procedural success. Technologic advancements, such as the use of nitinol U-clips (Coalescent Surgical Inc., Sunnyvale, CA) instead of sutures requiring manual knot tying, have been shown to decrease operative times significantly. It is expected that with further refinements and development of adjunct technologies, the technique of computer-enhanced endoscopic cardiac surgery will evolve and may prove to be beneficial for many patients. Robotic technology has provided benefits to cardiac surgery. With improved optics and instrumentation, incisions are smaller. The ergometric movements and simulated three-dimensional optics project hand-eye coordination for the surgeon. The placement of the wristlike articulations at the end of the instruments moves the pivoting action to the plane of the mitral annulus. This improves dexterity in tight spaces and allows for ambidextrous suture placement. Sutures can be placed more accurately because of tremor filtration and high-resolution video magnification. Furthermore, the robotic system may have potential as an educational tool. In the near future, surgical vision and training systems might be able to model most surgical procedures through immersive technology. Thus, a "flight simulator" concept emerges where surgeons may be able to practice and perform the operation without a patient. Already, effective curricula for training teams in robotic surgery exist. Nevertheless, certain constraints continue to limit the advancement to a totally endoscopic computer-enhanced mitral valve operation. The current size of the instruments, intrathoracic instrument collisions, and extrathoracic "elbow" conflicts still can limit dexterity. When smaller instruments are developed, these restraints may be resolved. Furthermore, a working port incision is still required for

  17. Valve-related complications after mechanical heart valve implantation.

    Science.gov (United States)

    Misawa, Yoshio

    2015-10-01

    The number of heart valve surgeries is increasing, and 19,164 patients underwent heart valve surgery in Japan in 2011. The early mortality rate has remained stable for more than 10 years. Many patients now survive for many years, with a reported 10-year survival rate of at least 60 %. However, unfavorable complications can occur after valve surgery. Valve-related complications include thromboembolisms, bleeding complications and prosthetic valve endocarditis, followed by structural and nonstructural prosthetic valve dysfunctions. Our review of studies published after 2000 revealed that the rate of all valve-related complications was 0.7-3.5 % per patient-year. Thromboembolisms occur at a rate of approximately 1 % per patient-year, and bleeding complications occur at almost 0.5 % per patient-year. Thromboembolic and hemorrhagic events related to anticoagulant therapy should be considered during life-long follow-up. The occurrence rate of endocarditis reaches 0.5 % per patient-year, with a poor postoperative survival. Structural dysfunctions have been largely overcome, and the nonstructural dysfunction rate is 0.4-1.2 % per patient-year. The nonstructural dysfunctions induced by paravalvular leaks and pannus ingrowth are also issues that need to be resolved.

  18. Patents and heart valve surgery - II: tissue valves.

    Science.gov (United States)

    Cheema, Faisal H; Kossar, Alexander P; Rehman, Atiq; Younas, Fahad; Polvani, Gianluca

    2013-08-01

    Valvular heart disease affects millions of Americans yearly and currently requires surgical intervention to repair or replace the defective valves. Through a close-knit collaboration between physicians, scientists and biomedical engineers, a vast degree of research and development has been aimed towards the optimization of prosthetic heart valves. Although various methods have made fantastic strides in producing durable prostheses, the therapeutic efficacy of prosthetic valves is inherently limited by a dependency upon lifelong anticoagulant regimens for recipients - a difficult challenge for many in clinical setting. Thus, biological tissue valves have been developed to circumvent vascular and immunemediated complications by incorporating biological materials to mimic native valves while still maintaining a necessary level of structural integrity. Over the past decade, a multitude of patents pertaining to the refinement of designs as well as the advancement in methodologies and technologies associated with biological tissue valves have been issued. This review seeks to chronicle and characterize such patents in an effort to track the past, present, and future progress as well as project the trajectory of tissue valves in the years to come.

  19. Space Shuttle Program (SSP) Orbiter Main Propulsion System (MPS) Gaseous Hydrogen (GH2) Flow Control Valve (FCV) Poppet Eddy Current (EC) Inspection Probability of Detection (POD) Study. Volume 2; Appendices

    Science.gov (United States)

    Piascik, Robert S.; Prosser, William H.

    2011-01-01

    The Director of the NASA Engineering and Safety Center (NESC), requested an independent assessment of the anomalous gaseous hydrogen (GH2) flow incident on the Space Shuttle Program (SSP) Orbiter Vehicle (OV)-105 during the Space Transportation System (STS)-126 mission. The main propulsion system (MPS) engine #2 GH2 flow control valve (FCV) LV-57 transition from low towards high flow position without being commanded. Post-flight examination revealed that the FCV LV-57 poppet had experienced a fatigue failure that liberated a section of the poppet flange. The NESC assessment provided a peer review of the computational fluid dynamics (CFD), stress analysis, and impact testing. A probability of detection (POD) study was requested by the SSP Orbiter Project for the eddy current (EC) nondestructive evaluation (NDE) techniques that were developed to inspect the flight FCV poppets. This report contains the Appendices to the main report.

  20. 一种用于电磁阀控制的 CAN 总线数据传输协议设计%Design of A CAN Bus Data Transfer Protocol for Solenoid Valve Control

    Institute of Scientific and Technical Information of China (English)

    张星; 张建国; 周畅; 付道俊

    2016-01-01

    CAN 总线凭借其优越性已成为应用最为广泛的现场总线之一。针对电磁阀控制系统,论文提出一种 CAN 总线数据传输协议,详细描述了协议实现,经过测试验证了其良好效果。%CAN bus has become one of the most widely used field bus with its advantages .For solenoid valve control system ,this paper proposes a CAN bus data transfer protocol ,and describes its implementation in detail .The result of tests verifies the protocol’s good benefits .

  1. A LabVIEW(®)-based software for the control of the AUTORAD platform: a fully automated multisequential flow injection analysis Lab-on-Valve (MSFIA-LOV) system for radiochemical analysis.

    Science.gov (United States)

    Barbesi, Donato; Vicente Vilas, Víctor; Millet, Sylvain; Sandow, Miguel; Colle, Jean-Yves; Aldave de Las Heras, Laura

    2017-01-01

    A LabVIEW(®)-based software for the control of the fully automated multi-sequential flow injection analysis Lab-on-Valve (MSFIA-LOV) platform AutoRAD performing radiochemical analysis is described. The analytical platform interfaces an Arduino(®)-based device triggering multiple detectors providing a flexible and fit for purpose choice of detection systems. The different analytical devices are interfaced to the PC running LabVIEW(®)VI software using USB and RS232 interfaces, both for sending commands and receiving confirmation or error responses. The AUTORAD platform has been successfully applied for the chemical separation and determination of Sr, an important fission product pertinent to nuclear waste.

  2. 水力喷砂割缝设备微型流量控制阀的特性计算%FLOW RATE CALCULATION OF MINIATURE FLOW CONTROL VALVE OF THE WATER JETTING SLIT-CUT EQUIPMENT

    Institute of Scientific and Technical Information of China (English)

    王学滨; 李成全; 张永利; 邰英楼; 章梦涛

    2001-01-01

    利用流体力学有关原理,导出阿基米德螺线槽流量特性方程,为水力喷砂割缝设备微型流量控制阀的设计、制造、实验、应用提供了初步理论依据。%Based on the principle of hydrodynamics,this paper deduces an equation,which shows a flow rate-relative pressure relation of Archimedes spiral groove.The equation has preliminarily supplied a theoretical foundation for design,manufacture,experiment and application of miniature flow control valve of the water jetting slit-cut equipment.

  3. Space Shuttle Program (SSP) Orbiter Main Propulsion System (MPS) Gaseous Hydrogen (GH2) Flow Control Valve (FCV) Poppet Eddy Current (EC) Inspection Probability of Detection (POD) Study. Volume 1

    Science.gov (United States)

    Piascik, Robert S.; Prosser, William H.

    2011-01-01

    The Director of the NASA Engineering and Safety Center (NESC), requested an independent assessment of the anomalous gaseous hydrogen (GH2) flow incident on the Space Shuttle Program (SSP) Orbiter Vehicle (OV)-105 during the Space Transportation System (STS)-126 mission. The main propulsion system (MPS) engine #2 GH2 flow control valve (FCV) LV-57 transition from low towards high flow position without being commanded. Post-flight examination revealed that the FCV LV-57 poppet had experienced a fatigue failure that liberated a section of the poppet flange. The NESC assessment provided a peer review of the computational fluid dynamics (CFD), stress analysis, and impact testing. A probability of detection (POD) study was requested by the SSP Orbiter Project for the eddy current (EC) nondestructive evaluation (NDE) techniques that were developed to inspect the flight FCV poppets. This report contains the findings and recommendations from the NESC assessment.

  4. Control means to improve the gas fire extinguishing system fire valve%改进气体灭火系统防烟防火阀的控制方式

    Institute of Scientific and Technical Information of China (English)

    刘文飞

    2014-01-01

    介绍了深圳地铁三号线气体灭火系统,分析了该系统原防烟防火阀的控制方式,从安全可靠的角度出发,提出了合理的改造方案,并加以实施,达到预期的效果,创造了经济效益。%Introduced the Shenzhen metro line no.3 gas fire-extinguishing systems,analyzes the system of the fire valve control mode of original,from the point of view of safe and reliable,put forward the reasonable reconstruction scheme,and implement,to achieve the expected effect,create the economic benefit.

  5. Self-Rupturing Hermetic Valve

    Science.gov (United States)

    Tucker, Curtis E., Jr.; Sherrit, Stewart

    2011-01-01

    For commercial, military, and aerospace applications, low-cost, small, reliable, and lightweight gas and liquid hermetically sealed valves with post initiation on/off capability are highly desirable for pressurized systems. Applications include remote fire suppression, single-use system-pressurization systems, spacecraft propellant systems, and in situ instruments. Current pyrotechnic- activated rupture disk hermetic valves were designed for physically larger systems and are heavy and integrate poorly with portable equipment, aircraft, and small spacecraft and instrument systems. Additionally, current pyrotechnically activated systems impart high g-force shock loads to surrounding components and structures, which increase the risk of damage and can require additional mitigation. The disclosed mechanism addresses the need for producing a hermetically sealed micro-isolation valve for low and high pressure for commercial, aerospace, and spacecraft applications. High-precision electrical discharge machining (EDM) parts allow for the machining of mated parts with gaps less than a thousandth of an inch. These high-precision parts are used to support against pressure and extrusion, a thin hermetically welded diaphragm. This diaphragm ruptures from a pressure differential when the support is removed and/or when the plunger is forced against the diaphragm. With the addition of conventional seals to the plunger and a two-way actuator, a derivative of this design would allow nonhermetic use as an on/off or metering valve after the initial rupturing of the hermetic sealing disk. In addition, in a single-use hermetically sealed isolation valve, the valve can be activated without the use of potential leak-inducing valve body penetrations. One implementation of this technology is a high-pressure, high-flow-rate rupture valve that is self-rupturing, which is advantageous for high-pressure applications such as gas isolation valves. Once initiated, this technology is self

  6. PWR safety and relief valve test program. Valve selection/juftification report. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1982-12-01

    NUREG 0578 required that full-scale testing be performed on pressurizer safety valves and relief valves representative of those in use or planned for use in PWR plants. To obtain valve performance data for the entire population of PWR plant valves, nine safety valves and ten relief valves were selected as a fully representative set of test valves. Justification that the selected valves represent all PWR plant valves was provided by each safety and relief valve manufacturer. Both the valve selection and justification work was performed as part of the PWR Safety and Relief Valve Test Program conducted by EPRI on behalf of the PWR utilities in response to the recommendations of NUREG 0578 and the requirements of the NRC. Results of the Safety and Relief Valve Selection and Justification effort is documented in this report.

  7. 船用多液动蝶阀启闭液压控制系统的设计%Design on Hydraulic Control System for Marine Muliti-hydraulic Butterfly Valve On-off

    Institute of Scientific and Technical Information of China (English)

    于娜; 杨志贤; 毛卫平; 顾寄南

    2016-01-01

    A hydraulic system to realize the marine butterfly valve open-shut and opening was designed, and the project of the hy-draulic control system was made. Combining with the actual working condition of the system, the selection and parameter of the main components of the hydraulic system were analyzed and calculated. Considering the working feature of the hydraulic control system for marine butterfly valve, the hydraulic power unit was designed in automatic unloading mode and the accumulator was added to supply hydraulic oil assistantly in order to ensure the pressure maintain within the allowable scope of the work, and the safe and stable opera-tion of the whole system are ensured.%设计了一种船用蝶阀启、 闭液压控制系统,确定了该液压系统的控制方案;结合该系统的实际工况要求,对该系统中各主要元件的选型和参数进行了分析和计算;结合船用蝶阀液压遥控系统的工作特点,对液压泵站进行了设计,设置两台液压泵互为备用,并增加蓄能器辅助供油,同时泵站采用自动卸荷方式,保证系统油压维持在允许的工作范围内,从而确保了整个船用阀门液压遥控系统的的安全稳定运行.

  8. Valve Health Monitoring System Utilizing Smart Instrumentation

    Science.gov (United States)

    Jensen, Scott L.; Drouant, George J.

    2006-01-01

    The valve monitoring system is a stand alone unit with network capabilities for integration into a higher level health management system. The system is designed for aiding in failure predictions of high-geared ball valves and linearly actuated valves. It performs data tracking and archiving for identifying degraded performance. The data collection types are cryogenic cycles, total cycles, inlet temperature, body temperature torsional strain, linear bonnet strain, preload position, total travel and total directional changes. Events are recorded and time stamped in accordance with the IRIG B True Time. The monitoring system is designed for use in a Class 1 Division II explosive environment. The basic configuration consists of several instrumentation sensor units and a base station. The sensor units are self contained microprocessor controlled and remotely mountable in three by three by two inches. Each unit is potted in a fire retardant substance without any cavities and limited to low operating power for maintaining safe operation in a hydrogen environment. The units are temperature monitored to safeguard against operation outside temperature limitations. Each contains 902-928 MHz band digital transmitters which meet Federal Communication Commission's requirements and are limited to a 35 foot transmission radius for preserving data security. The base-station controller correlates data from the sensor units and generates data event logs on a compact flash memory module for database uploading. The entries are also broadcast over an Ethernet network. Nitrogen purged National Electrical Manufactures Association (NEMA) Class 4 enclosures are used to house the base-station

  9. The Design of Impact Test-Bed for High-Flow Water Medium Relief Valve

    Directory of Open Access Journals (Sweden)

    Junliang Chang

    2014-11-01

    Full Text Available Water medium hydraulic systems are widely used in coal mining machinery. As the power of hydraulic system becomes higher, the flow and pressure of water medium relief valve are also higher, and the flow may reach 2000 L/min. However, there is no relevant test-bed which could provide instantaneous high-pressure and high-flow to support the experiment for high-flow relief valve; consequently, this impact test-bed for high-flow water medium relief valve is designed to satisfy fast loading demand. Through building model, simulation analysis, and construction of an impact test-bed of high-flow water medium relief valve, the dynamic performance of high-flow water medium relief valve is detected. The setting pressure of relief valve, the accumulator volume and the filling fluid pressure, and the damping of cartridge valve can be changed, and the dynamic performance of high-flow water medium relief valve under different impact loads is detected. The results show that the designed impact test-bed of high-flow water medium relief valve could provide required high-pressure and high-flow emulsion for the tested water medium relief valve, and it could control the strength of impact load, which is an energy saving, high efficiency, and low cost method.

  10. A Study of the Gas Flow through a LNG Safety Valve

    Institute of Scientific and Technical Information of China (English)

    Heuy-Dong Kim; Jun-Hee Lee; Kyung-Am Park; Toshiaki Setoguchi; Shigeru Matsuo

    2006-01-01

    A safety valve functions to control an upper limit of pressure inside the LNG line of transportation.If the pressure inside the safety valve nozzle exceeds a pre-determined value on the valve sheet which plugs the nozzle,an excess of LNG discharges through the gap between the nozzle exit and valve sheet.In this situation,the forces acting on the valve sheet are gasdynamic forces generated by the discharge of LNG and mechanical forces supported by the spring behind the valve sheet.The flow through the gap is very complicated,involving vortices,flow separation,and shock waves.These affect adversely on the system accompanying with noise and vibration.The present study aims at understanding the flow physics of safety valve.A computational work using the twodimensional,axisymmetric,compressible Navier-Stokes equations is carried out to simulate the gas flow between the nozzle exit and valve sheet,and compared with the theoretical results.It has been found that there exists a distance between nozzle exit and valve sheet in which the thrust coefficient at the valve sheet increases abruptly.

  11. 42 CFR 84.137 - Inhalation and exhalation valves; check valves; minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Inhalation and exhalation valves; check valves... PROTECTIVE DEVICES Supplied-Air Respirators § 84.137 Inhalation and exhalation valves; check valves; minimum requirements. (a) Inhalation and exhalation valves shall be provided where necessary and protected...

  12. 49 CFR 195.116 - Valves.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Valves. 195.116 Section 195.116 Transportation... PIPELINE Design Requirements § 195.116 Valves. Each valve installed in a pipeline system must comply with the following: (a) The valve must be of a sound engineering design. (b) Materials subject to...

  13. 14 CFR 125.133 - Fuel valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Fuel valves. 125.133 Section 125.133....133 Fuel valves. Each fuel valve must— (a) Comply with § 125.155; (b) Have positive stops or suitable... operation or from accelerated flight conditions are not transmitted to the lines connected to the valve....

  14. 49 CFR 192.145 - Valves.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Valves. 192.145 Section 192.145 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Design of Pipeline Components § 192.145 Valves. (a) Except for cast iron and plastic valves, each valve must meet the minimum requirements of API...

  15. 14 CFR 125.137 - Oil valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Oil valves. 125.137 Section 125.137....137 Oil valves. (a) Each oil valve must— (1) Comply with § 125.155; (2) Have positive stops or... the valve. (b) The closing of an oil shutoff means must not prevent feathering the propeller,...

  16. 基于Labview和Matlab对阀控非对称缸控制系统的联合仿真%Joint Simulation of Valve Controlled Asymmetrical Cylinder System Based on Labview and Matlab

    Institute of Scientific and Technical Information of China (English)

    武伟; 刘少军; 檀甲友; 赵玉洁

    2011-01-01

    The heave motion simulation platform of deep-ocean mining vessel is dealt with The control algorithm with all the indexes fitling requirements of actual motion in platform, stimulation is studied Aiming at the fuzzy self-tuning PID control of deep-ocean mining vessel valve controlltd asymmetrical cylinder, the joint controlled simulation is carried out by using Labview and Matlab/Simulink.And a nonlinear mathematical model of valve controlled asymmetrical cylinder system is established.The corresponding fuzzy self-tuning PID controller is designed The combination of the powerful controlled simulation function of Matlab and the flexibility, openness and software instrument of Labview is obtained.The simulation results show the correctness and feasibility of designed control algorithm.The visibillty, convenience of parameter adjusting and output interface performancc, make it be useful for design and construction of project, having certain practical value.%深海采矿船升沉运动模拟平台是用来模拟海浪作用下海上作业平台的升沉运动.为得到符合平台模拟实际运动中各项技术指标要求的控制算法,利用Labview界面仿真工具包SIT,针对深海采矿船升沉运动模拟平台的阀控非对称缸模糊自整定PID控制系统的实现过程,在Labview和Matlab/Simulink中进行了联合控制仿真,且建立了阀控非对称缸系统的非线性数学模型,设计了相应的模糊自整定PID控制器,把Matlab强大的控制仿真功能与Labview灵活、开放、"软件仪器"功能的特点很好结合,实现了优势互补,仿真验证了设计的控制算法的正确和可行.其可视性,方便的参数调整、输出界面效果等均为课题的设计与制造提供了便利,具有一定的实用价值.

  17. Double prosthetic aortic valve. Case report.

    Science.gov (United States)

    Liddicoat, J E; Bekassy, S M; De Bakey, M E

    1975-05-01

    A 55-year-old man underwent insection of a Hufnagel valve into his descending thoracic aorta for aortic valve insufficiency 18 years ago. He remained asymptomatic for 16 years. Because of progressive left ventricular failure his incompetent aortic valve was replaced with a De Bakey carbon ball aortic valve prosthesis 2 years later. Currently, 21 months after the operation, he is doing well with two aortic valves. Review of the literature suggests that he is the first patient reported with two aortic valves functioning concomitantly and one of the longest surviving patients with a Hufnagel valve.

  18. Transcatheter, valve-in-valve transapical aortic and mitral valve implantation, in a high risk patient with aortic and mitral prosthetic valve stenoses

    Directory of Open Access Journals (Sweden)

    Harish Ramakrishna

    2015-01-01

    Full Text Available Transcatheter valve implantation continues to grow worldwide and has been used principally for the nonsurgical management of native aortic valvular disease-as a potentially less invasive method of valve replacement in high-risk and inoperable patients with severe aortic valve stenosis. Given the burden of valvular heart disease in the general population and the increasing numbers of patients who have had previous valve operations, we are now seeing a growing number of high-risk patients presenting with prosthetic valve stenosis, who are not potential surgical candidates. For this high-risk subset transcatheter valve delivery may be the only option. Here, we present an inoperable patient with severe, prosthetic valve aortic and mitral stenosis who was successfully treated with a trans catheter based approach, with a valve-in-valve implantation procedure of both aortic and mitral valves.

  19. Internal Acoustics of a Pintle Valve with Supercritical Helium Flow

    Science.gov (United States)

    Fishbach, Sean R.; Davis, R. Benjamin

    2010-01-01

    Large amplitude flow unsteadiness is a common phenomenon within the high flow rate ducts and valves associated with propulsion systems. Boundary layer noise, shear layers and vortex shedding are a few of the many sources of flow oscillations. The presence of lightly damped acoustic modes can organize and amplify these sources of flow perturbation, causing undesirable loading of internal parts. The present study investigates the self-induced acoustic environment within a pintle valve subject to high Reynolds Number flow of helium gas. Experiments were conducted to measure the internal pressure oscillations of the Ares I Launch Abort System (LAS) Attitude Control Motor (ACM) valve. The AGM consists of a solid propellant gas generator with eight pintle valves attached to the aft end. The pintle valve is designed to deliver variable upstream conditions to an attache( converging diverging nozzle. In order to investigate the full range of operating conditions 28 separate tests were conducted with varying pintle position and upstream pressure. Helium gas was utilized in order to closely mimic the speed of sound of the gas generator exhaust, minimizing required scaling during data analysis. The recordec pressure measurements were interrogated to multiple ends. The development of root mean square (RMS) value! versus Reynolds Number and Pintle position are important to creating bounding unsteady load curves for valve internal parts. Spectral analysis was also performed, helping to identify power spectral densities (PSD) of acoustic natural frequencies and boundary layer noise. An interesting and unexpected result was the identification of an acoustic mode within the valve which does not respond until the valve was over 60% open. Further, the response amplitude around this mode can be as large or larger than those associated with lower frequency modes.

  20. A computerized system for video analysis of the aortic valve.

    Science.gov (United States)

    Vesely, I; Menkis, A; Campbell, G

    1990-10-01

    A novel technique was developed to study the dynamic behavior of the porcine aortic valve in an isolated heart preparation. Under the control of a personal computer, a video frame grabber board continuously acquired and digitized images of the aortic valve, and an analog-to-digital (A/D) converter read four channels of physiological data (flow rate, aortic and ventricular pressure, and aortic root diameter). The valve was illuminated with a strobe light synchronized to fire at the field acquisition rate of the CCD video camera. Using the overlay bits in the video board, the measured parameters were super-imposed over the live video as graphical tracing, and the resultant composite images were recorded on-line to video tape. The overlaying of the valve images with the graphical tracings of acquired data enabled the data tracings to be precisely synchronized with the video images of the aortic valve. This technique enabled us to observe the relationship between aortic root expansion and valve function.

  1. Design factors for “linear” ball valve: theoretical and experimental studies

    Directory of Open Access Journals (Sweden)

    Thananchai Leephakpreeda

    2005-03-01

    Full Text Available Generic non-linear flow characteristics of the conventional ball valve limit the applications of flow modulation in fluid processes. This work presents the flow characteristics of fluid flowing through the conventional and modified ball valves for feasibility of a “linear” ball valve. Theoretical studies are discussed for determining explicit and implicit factors on the valve coefficient, which modulates the flow rate of fluid when the ball valve is operated in flow control processes. In experiment, the cross- sectional opening area at various opening degrees, the shape, and the location of the hole passage in valve ball are examined for complicated relations dependent to the flow rate of fluid. It can be concluded that those factors cause the modulation of flow rate when the ball is turned at different opening degree. In extended design of flow characteristics for linearity, they are to be taken into account.

  2. DYNAMIC CHARACTERISTICS OF LARGE FLOW RATING ELECTRO-HYDRAULIC PROPORTIONAL CARTRIDGE VALVE

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A kind of cartridge servo proportional valve is discussed, which can be used for controlling large flow rate with high performance. By analyzing the structure principle of the valve, the transfer function of the valve is derived. With the transfer function, some structure elements that may affect its performance are investigated. Through the numerical simulation and test study, some principles of optimality and effective methods for improving the dynamic performance of the valve are proposed. The test results conform to the results of the theoretical analysis and simulation, which proves the correctness of the study and simulation works. The paper provides theoretical basis for engineering applications and series expanding design works.

  3. Remote Diagnosis of Valve Control System Based on Public Telephone Network%基于公用电话网的阀门控制远程诊断系统

    Institute of Scientific and Technical Information of China (English)

    王道顺; 李芍君

    2011-01-01

    The mechanism of remote diagnosis system design methods is introduced using VB as a host computer before the panel to Mega16 crew for the next core,and public telephone network as a data transmission medium of valve control. Field data are collected through the analog switch, and the data are transferred through MODEM via telephone network to a host computer,using host computer interface for data analysis and determining equipment failure. This diagnostic system is designed for remote diagnostics and field fault diagnosis to provide users with a variety of options suitable to resolve system failures quickly. The system has been successfully applied to a valve fault detection system.%介绍了以VB作为上位机前面板,以Mega16为下位机核心,采用公用电话网作为数据传输介质的阀门控制远程诊断系统的设计方法及工作原理.该系统通过模拟开关采集现场数据,并通过MODEM经由电话网将数据传送到上位机,利用VB制作的上位机界面对数据进行分析,判断设备故障所在.所设计诊断系统,不仅可以进行远程诊断,也可以根据实际情况在现场进行故障诊断,为用户提供了多种选择,方便用户以最适合自己的方式来快速解决系统故障.该系统已成功应用于阀门故障检测系统中.

  4. Human tissue valves in aortic position: determinants of reoperation and valve regurgitation

    NARCIS (Netherlands)

    T.P. Willems (Tineke); E.W. Steyerberg (Ewout); V.E. Kleyburg-Linkers; E. Bos (Egbert); L.A. van Herwerden (Lex); J.R.T.C. Roelandt (Jos); J.J.M. Takkenberg (Hanneke)

    2001-01-01

    textabstractBACKGROUND: Human tissue valves for aortic valve replacement have a limited durability that is influenced by interrelated determinants. Hierarchical linear modeling was used to analyze the relation between these determinants of durability and valve

  5. Comparison of outcomes after aortic valve replacement with a mechanical valve or a bioprosthesis using microsimulation

    NARCIS (Netherlands)

    J.P.A. Puvimanasinghe (John); M.B. Edwards; M.J.C. Eijkemans (René); E.W. Steyerberg (Ewout); L.A. van Herwerden (Lex); K.M. Taylor; G.L. Grunkemeier (Gary); J.D.F. Habbema (Dik); A.J.J.C. Bogers (Ad); J.J.M. Takkenberg (Hanneke)

    2004-01-01

    textabstractBACKGROUND: Mechanical valves and bioprostheses are widely used for aortic valve replacement. Though previous randomised studies indicate that there is no important difference in outcome after implantation with either type of valve, knowledge of outcomes after aortic va

  6. Transient flow analysis of integrated valve opening process

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xinming; Qin, Benke; Bo, Hanliang, E-mail: bohl@tsinghua.edu.cn; Xu, Xingxing

    2017-03-15

    Highlights: • The control rod hydraulic driving system (CRHDS) is a new type of built-in control rod drive technology and the integrated valve (IV) is the key control component. • The transient flow experiment induced by IV is conducted and the test results are analyzed to get its working mechanism. • The theoretical model of IV opening process is established and applied to get the changing rule of the transient flow characteristic parameters. - Abstract: The control rod hydraulic driving system (CRHDS) is a new type of built-in control rod drive technology and the IV is the key control component. The working principle of integrated valve (IV) is analyzed and the IV hydraulic experiment is conducted. There is transient flow phenomenon in the valve opening process. The theoretical model of IV opening process is established by the loop system control equations and boundary conditions. The valve opening boundary condition equation is established based on the IV three dimensional flow field analysis results and the dynamic analysis of the valve core movement. The model calculation results are in good agreement with the experimental results. On this basis, the model is used to analyze the transient flow under high temperature condition. The peak pressure head is consistent with the one under room temperature and the pressure fluctuation period is longer than the one under room temperature. Furthermore, the changing rule of pressure transients with the fluid and loop structure parameters is analyzed. The peak pressure increases with the flow rate and the peak pressure decreases with the increase of the valve opening time. The pressure fluctuation period increases with the loop pipe length and the fluctuation amplitude remains largely unchanged under different equilibrium pressure conditions. The research results lay the base for the vibration reduction analysis of the CRHDS.

  7. 阀控液压马达速度伺服系统仿真分析%Simulation of the Hydraulic Motor of Speed Servo System Controlled by Valve

    Institute of Scientific and Technical Information of China (English)

    贾文铜; 周瑞祥; 张忠

    2012-01-01

    针对干扰力矩对阀控液压马达速度伺服系统的影响,利用结构不变性原理给系统加入了补偿器来消除干扰力矩的影响,同时利用PID控制来提高系统的抗干扰性.仿真表明,在利用结构不变性原理后再通过PID控制可以有效提高系统抗干扰能力和控制精度.%Aiming at the interfere moment affecting the hydraulic motor of speed servo system controlled by valve,the structure unchangeable principle was applied to eliminate the effect of the interfere moment and PID control was also managed to enhance the anti-jamming of the system, The simulation indicates that the application of the PID controll after the application of structure unchangeable principle can effectively improve the anti-jamming ability and control precision.

  8. Micro Steam Turbine Proportional Valve Control Unit Retrofit Analysis%小汽轮机比例阀驱动控制单元技术改造分析

    Institute of Scientific and Technical Information of China (English)

    冯康

    2013-01-01

    针对华能国际电力股份有限公司上安电厂350 M W机组小汽轮机调速系统在遇到外界干扰时,汽包水位难以控制的问题,提出小汽轮机比例阀驱动单元及电源配置改造中的安装施工方案和设备调试方案,分析改造效果,认为改造后比例驱动单元运行情况良好,小汽轮机进汽调门运行稳定。%The micro steam turbine speed control system of Huaneng Power International Inc S.hang′an Power Plant 350 MW unit is difficult to control the water level when encoun-tered outside interference .This paper advances the install construction project of micro steam turbine proportional valve control unit and power configuration ,analyzes reforma-tion effects considers that proportion drive unit operates well ,micro steam control door operates stably .

  9. Performance and Purposes of Balance Valves in Heating System%供热系统中平衡阀的性能与用途

    Institute of Scientific and Technical Information of China (English)

    程鹏

    2011-01-01

    本文主要阐述了供热系统中手动平衡阀、自力式压差控制阀、自力式流量控制阀、自力式流量控制阀的选择、自力式流量控制阀在暖通工程中的应用等问题.%This paper describes the application of manual balancing valve in heating system, self-operated pressure control valve, operated flow control valve, operated flow control valve selection and self-operated flow control valve in the HVAC engineering, etc. in HAVC project.

  10. Simpler valve for reciprocating engines

    Science.gov (United States)

    Akkerman, J. W.

    1978-01-01

    Simpler design eliminating camshafts, cams, and mechanical springs should improve reliability of hydrazine powered reciprocating engines. Valve is expected to improve efficiency, and reduce weight of engines in range up to 50 horsepower.

  11. Titanium in engine valve systems

    Energy Technology Data Exchange (ETDEWEB)

    Allison, J.E.; Sherman, A.M.; Bapna, M.R.

    1987-03-01

    Titanium alloys offer a unique combination of high strength-to-weight ratio, good corrosion resistance and favorable high temperature mechanical properties. Still, their relatively high cost has discouraged consideration for widespread use in automotive components. Recent demands for increased fuel economy have led to the consideration of these alloys for use as valve train materials where higher costs might be offset by improvements in performance and fuel economy. Lighter weight valve train components permit the use of lower spring loads, thus reducing friction and increasing fuel economy. Camshaft friction measurements made on a typical small displacement engine indicate that a two-to-four percent increase in fuel economy can be achieved. Valve train components are, however, subject to a severe operating environment, including elevated temperatures, sliding wear and high mechanical loads. This paper discusses the details of alloy and heat treatment selection for optimizing valve performance.

  12. Diseases of the Tricuspid Valve

    Science.gov (United States)

    ... Kawasaki Disease Long Q-T Syndrome Marfan Syndrome Metabolic Syndrome Mitral Valve Prolapse Myocardial Bridge Myocarditis Obstructive Sleep Apnea Pericarditis Peripheral Vascular Disease Rheumatic Fever Sick Sinus Syndrome Silent Ischemia Stroke Sudden ...

  13. What Causes Heart Valve Disease?

    Science.gov (United States)

    ... a heart attack or injury to the heart. Rheumatic Fever Untreated strep throat or other infections with strep bacteria that progress to rheumatic fever can cause heart valve disease. When the body ...

  14. CONGENITAL QUADRICUSPID AORTIC-VALVE

    NARCIS (Netherlands)

    BROUWER, MHJ; DEGRAAF, JJ; EBELS, T

    1993-01-01

    Two patients with a quadricuspid aortic valve are described, one of them with concomitant juxtaposed coronary orifices facing the right hand facing sinus. The etiology and incidence of this congenital anomaly will be discussed.

  15. Minimally invasive aortic valve replacement

    DEFF Research Database (Denmark)

    Foghsgaard, Signe; Schmidt, Thomas Andersen; Kjaergard, Henrik K

    2009-01-01

    In this descriptive prospective study, we evaluate the outcomes of surgery in 98 patients who were scheduled to undergo minimally invasive aortic valve replacement. These patients were compared with a group of 50 patients who underwent scheduled aortic valve replacement through a full sternotomy....... The 30-day mortality rate for the 98 patients was zero, although 14 of the 98 mini-sternotomies had to be converted to complete sternotomies intraoperatively due to technical problems. Such conversion doubled the operative time over that of the planned full sternotomies. In the group of patients whose...... is an excellent operation in selected patients, but its true advantages over conventional aortic valve replacement (other than a smaller scar) await evaluation by means of randomized clinical trial. The "extended mini-aortic valve replacement" operation, on the other hand, is a risky procedure that should...

  16. The spin-valve transistor

    NARCIS (Netherlands)

    Monsma, Douwe Johannes

    1998-01-01

    High density magnetic recording, magnetic random access memories, displacement and current detection, contactless switching and electronic compass applications all require magnetic field sensors with unprecedented sensitivity. The spin-valve effect (giant magnetoresistance) found in 1988 in magnetic

  17. Hydraulic System Design of Hydraulic Actuators for Large Butterfly Valves

    Directory of Open Access Journals (Sweden)

    Ye HUANG

    2014-09-01

    Full Text Available Hydraulic control systems of butterfly valves are presently valve-controlled and pump-controlled. Valve-controlled hydraulic systems have serious power loss and generate much heat during throttling. Pump-controlled hydraulic systems have no overflow or throttling losses but are limited in the speed adjustment of the variable-displacement pump, generate much noise, pollute the environment, and have motor power that does not match load requirements, resulting in low efficiency under light loads and wearing of the variable-displacement pump. To overcome these shortcomings, this article designs a closed hydraulic control system in which an AC servo motor drives a quantitative pump that controls a spiral swinging hydraulic cylinder, and analyzes and calculates the structure and parameters of a spiral swinging hydraulic cylinder. The hydraulic system adjusts the servo motor’s speed according to the requirements of the control system, and the motor power matches the power provided to components, thus eliminating the throttling loss of hydraulic circuits. The system is compact, produces a large output force, provides stable transmission, has a quick response, and is suitable as a hydraulic control system of a large butterfly valve.

  18. 57. Aortic valve replacement with sutureless valve and mitral valve repair in patient with infected aortic homograft

    Directory of Open Access Journals (Sweden)

    A. attia

    2016-07-01

    Full Text Available The approach of implanting aortic sutureless valve inside the calcific homograft is suitable in redo surgery especially if associated with mitral valve surgery. Aortic valve replacement in patients who have undergone previous aortic root replacement with an aortic homograft remains a technical challenge because of homograft degeneration and the need for a redo Bentall operation. We report a case of redo aortic valve replacement (valve in valve with a sutureless valve and mitral valve repair by miniband annuloplasty in a female patient aged 64 years old who underwent aortic valve replacement with homograft 14 years ago and presented by sever aortic valve regurge and sever mitral valve regurge because of infective endocarditis. This technique allows rapid aortic valve replacement in a heavily calcified aortic root. It also avoids aortic valve size affection after mitral valve repair by ordinary methods especially in patients with small aortic annulus. This technique is particularly suitable in redo procedures for homograft degeneration, it avoids performing a redo Bentall operation with its known problems as well as to avoid patient prosthesis mismatch.

  19. 新型SVC-M型磁阀式可控动态无功补偿技术研究%A new SVC-M-type magnetic valve controlled dynamic reactive power compensation technology

    Institute of Scientific and Technical Information of China (English)

    刘美荣

    2012-01-01

    磁阀式可控电抗器的出现为超高压、特高压电网的电压控制、无功调节提供了一种全新的技术手段.并联电容补偿方式因电气化铁路自然功率因数低,系统难以达到标准要求.新型磁阀式可控电抗器,可调节电气化铁路系统的无功功率,通过公式推导的方式对无功检测和控制回路进行理论分析,另一方面,对磁阀式可控电抗器的谐波特性、伏安特性、控制特性及响应特性分别进行了分析,给出各种特性曲线.设计将提高响应速度后的MVCR应用到电气化铁道动态无功补偿中,使用MVCR+FC进行动态补偿,且动态补偿效果良好.%The valve controllable reactor is a bran-new technical method to control the urtrahkjh voltage and the reactive power. Due to the low natural power factor in electrified railway system, the mode of compensation with parallel capacitor cant satisfy the standards. The new magnetic valve controiabte reactor could adjust the reactive power, and the reactive power and control loop were analyzed theoretically by formula derivation. The characteristics of harmonics, volt-ampere, control and response were analyzed also, and then- curves of characteristics were given. The MVCR with improved response speed was appied to the dynamic reactive compensation of electrified raSway and the compensation effects were exceBent with the MVCR matched with fixed capacitance (FC).

  20. System for detecting operating errors in a variable valve timing engine using pressure sensors

    Science.gov (United States)

    Wiles, Matthew A.; Marriot, Craig D

    2013-07-02

    A method and control module includes a pressure sensor data comparison module that compares measured pressure volume signal segments to ideal pressure volume segments. A valve actuation hardware remedy module performs a hardware remedy in response to comparing the measured pressure volume signal segments to the ideal pressure volume segments when a valve actuation hardware failure is detected.

  1. Development and experimental characterization of a pneumatic valve actuated by a dielectric elastomer membrane

    Science.gov (United States)

    Hill, Marc; Rizzello, Gianluca; Seelecke, Stefan

    2017-08-01

    Due to their many features including lightweight and low energy consumption, dielectric elastomer (DE) membrane actuators are of interest for a number of industrial applications, such as pumping systems or valve control units. In particular, the use of DEs in valve control units offers advantages over traditional solenoid valves, including lower power requirements and relative simplicity in achieving proportional control. Additionally, DEs generate low thermal dissipation and are capable of virtually silent operation. The contribution of this work is the development of a new valve system based on a circular DE membrane pre-loaded with a linear spring. The valve is designed for pressurized air and operates by actuating a lever mechanism that opens and closes an outlet port. After presenting the operating principle and system design, several experiments are presented to compare actuator force, stroke, and dissipated energy for several pressure differentials and associated volume flows. It is observed that the DE-driven valve achieves a performance similar to a solenoid-based valve, while requiring a significantly lower amount of input energy. In addition, it is shown that DE-membrane valves can be controlled proportionally by simply adjusting the actuator voltage.

  2. TCT-670 Optimal Transcatheter Heart Valve Sizing in Aortic Valve in Valve Implantation: Insights from the Valve in Valve International Data (VIVID) Registry

    DEFF Research Database (Denmark)

    Alnasser, Sami; Cheema, Asim N; Horlick, Eric

    2016-01-01

    Background: Optimal transcatheter heart valve (THV) sizing is crucial to optimize procedural outcomes. Larger THV oversizing is shown to decrease paravalvular leakage post transcatheter aortic valve replacement but its role in Valve in Valve implantation (ViV) is not well established. Methods...... group received a larger THV (25.5± 1.4 mm vs. 23.3 ± 1.0 mm, pimplantation, the oversized group achieved a larger EOA (1.54±0.4cm2 vs. 1.37± 0.5cm2, p...V implantation was associated with favorable post-implant EOA and gradient but a higher risk of aortic insufficiency and THV re-intervention. Further exploration within various THV and surgical valve types at different degree of THV oversizing is planned....

  3. Numerical simulation on a throttle governing system with hydraulic butterfly valves in a marine environment

    Science.gov (United States)

    Wan, Hui-Xiong; Fang, Jun; Huang, Hui

    2010-12-01

    Hydraulic butterfly valves have been widely applied in marine engineering because of their large switching torque, low pressure loss and suitability for large and medium diameter pipelines. Due to control problems resulting from switching angular speeds of the hydraulic butterfly valve, a throttle-governing control mode has been widely adopted, and detailed analysis has been carried out worldwide on the structural principle concerning speed-regulation and the load torque on the shaft while opening or closing a hydraulic butterfly valve. However relevant reports have yet been published on the change law, the error and the influencing factors of the rotational angular velocity of the hydraulic butterfly valve while opening and closing. In this article, research was based on some common specifications of a hydraulic butterfly valve with a symmetrical valve flap existing in a marine environment. The throttle governing system supplied by the accumulator to achieve the switching of the hydraulic control valve was adopted, and the mathematical models of the system were established in the actual conditions while the numerical simulations took place. The simulation results and analysis show that the rotational angular velocity and the error of the hydraulic butterfly valve while switching is influenced greatly by the drainage amount of the accumulator, resulting in pressure loss in the pipeline, the temperature of hydraulic medium and the load of the hydraulic butterfly valve. The simulation results and analysis provide a theoretical basis for the choice of the total capacity of the accumulator and pipeline diameters in a throttle governing system with a hydraulic butterfly valve. It also determines the type and specification of the hydraulic butterfly valve and the design of motion parameters of the transported fluid.

  4. Advanced Numerical Tools for Design and Analysis of In-Space, Valve and Feed Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In-space valves for the main fuel and oxidizer feed systems are required to provide precise control, wide throttling range and handle rapid on-off control. These...

  5. Advanced Numerical Tools for Design and Analysis of In-Space, Valve and Feed Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In-space valves are required to provide precise mass flow control, wide throttling range and handle rapid on-off control. These requirements can result in...

  6. Study on Friction and Wear Characteristics of Aluminum Alloy Hydraulic Valve Body and Its Antiwear Mechanism

    Directory of Open Access Journals (Sweden)

    Rong Li

    2017-03-01

    Full Text Available In order for the working status of the aluminum alloyed hydraulic valve body to be controlled in actual conditions, a new friction and wear design device was designed for the cast iron and aluminum alloyed valve bodies comparison under the same conditions. The results displayed that: (1 The oil leakage of the aluminum alloyed hydraulic valve body was higher than the corresponding oil leakage of the iron body during the initial running stage. Besides during a later running stage, the oil leakage of the aluminum alloyed body was lower than corresponding oil leakage of the iron body; (2 The actual oil leakage of different materials consisted of two parts: the foundation leakage that was the leakage of the valve without wear and wear leakage that was caused by the worn valve body; (3 The aluminum alloyed valve could rely on the dust filling furrow and melting mechanism that led the body surface to retain dynamic balance, resulting in the valve leakage preservation at a low level. The aluminum alloy modified valve body can meet the requirements of hydraulic leakage under pressure, possibly constituting this alloy suitable for hydraulic valve body manufacturing.

  7. 46 CFR 34.15-10 - Controls-T/ALL.

    Science.gov (United States)

    2010-10-01

    ... manual release or stop valve controls fail to operate. Each control valve to branch lines must be marked... Systems, Details § 34.15-10 Controls—T/ALL. (a) Except as noted in § 34.15-20(b), all controls and valves... valves shall be used to direct the carbon dioxide into the proper space. If cylinders are used to protect...

  8. LOFT pressurizer safety: relief valve reliability

    Energy Technology Data Exchange (ETDEWEB)

    Brown, E.S.

    1978-01-18

    The LOFT pressurizer self-actuating safety-relief valves are constructed to the present state-of-the-art and should have reliability equivalent to the valves in use on PWR plants in the U.S. There have been no NRC incident reports on valve failures to lift that would challenge the Technical Specification Safety Limit. Fourteen valves have been reported as lifting a few percentage points outside the +-1% Tech. Spec. surveillance tolerance (9 valves tested over and 5 valves tested under specification). There have been no incident reports on failures to reseat. The LOFT surveillance program for assuring reliability is equivalent to nuclear industry practice.

  9. Control arrangement for the actuation of hydraulic consumers

    Energy Technology Data Exchange (ETDEWEB)

    Kussel, W.; Dettmers, M.; Weirich, W.

    1988-11-09

    An arrangement for controlling the actuation of hydraulic consumers, by selectively connecting the consumers to hydraulic pressure and return lines; the control arrangement comprising a respective hydraulically operated directional control valve associated with each of the hydraulic consumers, a respective electro-magnetically operated pre-control valve associated with each of the hydraulic directional control valves, and further electro-magnetically operated directional control valve means associated with the pre-control valves, each of the hydraulic consumers being connectible to the hydraulic pressure or return lines via the associated hydraulically operated directional control valve which is actuatable by a hydraulic control line leading from the output of the associated pre-control valve, wherein the inputs of the pre-control valves are connected directly to the hydraulic return line and indirectly, via the further control valve means, to the hydraulic return line or to a hydraulic control pressure line.

  10. Lock Culvert Valves; Hydraulic Design Considerations

    Science.gov (United States)

    2011-06-01

    the U.S. Army Engineer Waterways Experiment Station and U.S. Army Engineer Districts, St. Paul and Walla Walla . The prototype data suggest that the...been issued (U.S. Army Engineer District, Walla Walla 1955). 4.4.2 Lock No. 19 Lock 19 has a lift of 38.2 ft and flow is controlled with 14.5- by...Army Engineer Waterways Experiment Station. U.S. Army Engineer District, Walla Walla . 1955. Synchronization of lock filling valves, McNary Lock

  11. Titanium in Engine Valve Systems

    Science.gov (United States)

    Allison, J. E.; Sherman, A. M.; Bapna, M. R.

    1987-03-01

    Titanium alloys offer a unique combination of high strength-to-weight ratio, good corrosion resistance and favorable high temperature mechanical properties. Still, their relatively high cost has discouraged consideration for widespread use in automotive components. Recent demands for increased fuel economy have led to the consideration of these alloys for use as valve train materials where higher costs might be offset by improvements in performance and fuel economy. Lighter weight valve train components permit the use of lower spring loads, thus reducing friction and increasing fuel economy. Camshaft friction measurements made on a typical small displacement engine indicate that a twoto-four percent increase in fuel economy can be achieved. Valve train components are, however, subject to a severe operating environment, including elevated temperatures, sliding wear and high mechanical loads. This paper discusses the details of alloy and heat treatment selection for optimizing valve performance. When properly manufactured, titanium valves have been shown to withstand very stringent durability testing, indicating the technical feasibility of this approach to fuel economy improvement.

  12. The use of check valve performance data to support new concepts (probabilistic risk assessment, condition monitoring) for check valve program

    Energy Technology Data Exchange (ETDEWEB)

    Hart, K.A.; Gower, D.

    1996-12-01

    The concept of developing an integrated check valve database based on the Nuclear Power Reliability Data System (NPRDS) data was presented at the last Symposium. The Nuclear Industry Check Valve Group (NIC), working in cooperation with the Oak Ridge National Laboratory (ORNL), has completed an operational database of check valve performance from 1984 to the present. NIC has committed to the nuclear industry to periodically update the data and maintain this information accessible. As the new concepts of probabilistic risk analysis and condition monitoring are integrated into the American Society of Mechanical Engineers (ASME) Code, a critical element will be performance data. From check valve performance data, feasible failure modes and rates can be established. When a failure rate or frequency of failures can be established based on a significant enough population (sampling), a more solid foundation for focusing resources and determining appropriate frequencies and testing can be determined. The presentation will give the updated status of the NIC Check Valve Performance Database covering (1) methodology used to combine the original ORNL data; (2) process/controls established for continuing update and refinement of the data; (3) discussion of how this data is being utilized by (a) OM-22 for condition monitoring, and (b) risk-based inservice testing work of Westinghouse Owners` Group; and (4) results/trends of data evaluations. At the 1994 Symposium, ORNL provided an update as of 1991 to their original work of 1984 -1990 which they had performed to characterize check valve degradations and failures in the nuclear industry. These characterizations will be updated to 1995 and additional reviews provided to give insight into the current condition and trends of check valve performance.

  13. The nordic aortic valve intervention (NOTION) trial comparing transcatheter versus surgical valve implantation

    DEFF Research Database (Denmark)

    Thyregod, Hans Gustav; Søndergaard, Lars; Ihlemann, Nikolaj;

    2013-01-01

    Degenerative aortic valve (AV) stenosis is the most prevalent heart valve disease in the western world. Surgical aortic valve replacement (SAVR) has until recently been the standard of treatment for patients with severe AV stenosis. Whether transcatheter aortic valve implantation (TAVI) can...

  14. Aortic valve replacement with the Nicks annulus enlargement procedure 12 years after mitral valve replacement.

    Science.gov (United States)

    Kazama, S; Kurata, A; Yamashita, Y

    1999-10-01

    An aortic valve replacement was successfully performed employing the Nicks annulus enlargement procedure in a case of aortic valve stenosis with small annulus 12 years after mitral valve replacement. Previous mitral valve replacement does not preclude feasibility of the Nicks procedure.

  15. Transapical transcatheter valve-in-valve replacement for deteriorated mitral valve bioprosthesis without radio-opaque indicators: the "invisible" mitral valve bioprosthesis.

    Science.gov (United States)

    Rossi, Marco Luciano; Barbaro, Cristina; Pagnotta, Paolo; Cappai, Antioco; Ornaghi, Diego; Belli, Guido; Presbitero, Patrizia

    2015-02-01

    In view of the high number of bioprosthetic valves implanted during the past 30 years, an increasing number of patients are coming to medical attention because of degenerated bioprostheses. Transcatheter aortic valve-in-valve implantation has been described as a less invasive alternative to re-operation to treat severe structural valve deterioration. As far as degenerated mitral valve bioprostheses are concerned, transcatheter transapical mitral valve-in-valve replacement (TMVR) has been less commonly performed, but may also become a viable alternative to re-do replacement surgery. We describe treatment of a degenerated bioprosthetic mitral valve, characterised by complete absence of any radio-opaque landmarks making the TMVR procedure very challenging.

  16. Percutaneous heart valves; past, present and future.

    Science.gov (United States)

    Rozeik, M M; Wheatley, D J; Gourlay, T

    2014-09-01

    Percutaneous heart valves provide a promising future for patients refused surgery on the grounds of significant technical challenges or high risk for complications. Since the first human intervention more than 10 years ago, over 50 different types of valves have been developed. The CoreValve and Edwards SAPIEN valves have both experienced clinical trials and the latter has gained FDA approval for implantation in patients considered inoperable. Current complications, such as major vascular bleeding and stroke, prevent these valves from being commonly deployed in patients considered operable in conventional surgery. This review focuses on the past and present achievements of these valves and highlights the design considerations required to progress development further. It is envisaged that, with continued improvement in valve design and with increased clinical and engineering experience, percutaneous heart valve replacement may one day be a viable option for lower-risk operable patients.

  17. A mechatronic valve in the management of hydrocephalus: methods and performance.

    Science.gov (United States)

    Momani, Lina; Al-Nuaimy, Waleed; Al-Jumaily, Mohammed; Mallucci, Conor

    2011-01-01

    The problem of excess cerebrospinal fluid in the brain (hydrocephalus) is generally managed using a passive pressure or flow regulated mechanical shunt. Despite the success of such devices, they have been plagued with a number of problems. It is desirable to have a shunt valve that responds dynamically to the changing needs of the patient, opening and closing according to a dynamic physiological pattern, rather than simply to the hydrostatic pressure across the valve. Such a valve would by necessity be mechatronic, electronically controlled by software. In this article, different methods for controlling such a mechatronic valve are explored, and the effect of current hydrocephalus management techniques on the intracranial hydrodynamics of acute hydrocephalus patient compared with those based on a mechatronic valve was investigated using numerical simulation. Furthermore, the performance of these techniques was evaluated based on a proposed multi-dimensional figure of merit. In addition, an empirical valve schedule was proposed based on different criterions. An intelligent shunting system is seen as the future in hydrocephalus management and treatment, and towards this end, suitably programmed mechatronic valves would attempt to mimic normal physiology and potentially overcome many of the problems associated with current mechanical valves.

  18. Prevention of crack initiation in valve bodies under thermal shock

    Energy Technology Data Exchange (ETDEWEB)

    Delmas, J.; Coppolani, P.

    1996-12-01

    On site and testing experience has shown that cracking in valves affects mainly the stellite hardfacing on seats and discs but may also be a concern for valve bodies. Metallurgical investigations conducted by EDF laboratories on many damaged valves have shown that most of the damage had either a chemical, manufacturing, or operating origin with a strong correlation between the origins and the type of damage. The chemical defects were either excess ferritic dilution of stellite or excess carburizing. Excess carburizing leads to a too brittle hardfacing which cracks under excessive stresses induced on the seating surfaces, via the stem, by too high operating thrusts. The same conditions can also induce cracks of the seats in the presence, in the hardfacing, of hidden defects generated during the welding process. Reduction of the number of defects results first from controls during manufacturing, mainly in the thickness of stellite. On the other hand, maintenance must be fitted to the type of defect. In-situ lapping may lead to release of cobalt, resulting in contamination of the circuit. Furthermore, it is ineffectual in the case of a crack through the seating surface, as is often found on globe valves. The use of new technologies of valves with removable seats and cobalt-free alloys solves permanently this kind of problem.

  19. 2D SIMPLIFIED SERVO VALVE

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A novel pilot stage valve called simplified 2D valve, which utilizes both rotary and linear motions of a single spool, is presented.The rotary motion of the spool incorporating hydraulic resistance bridge, formed by a damper groove and a crescent overlap opening, is utilized as pilot to actuate linear motion of the spool.A criterion for stability is derived from the linear analysis of the valve.Special experiments are designed to acquire the mechanical stiffness, the pilot leakage and the step response.It is shown that the sectional size of the spiral groove affects the dynamic response and the stiffness contradictorily and is also very sensitive to the pilot leakage.Therefore, it is necessary to establish a balance between the static and dynamic characteristics in deciding the structural parameters.Nevertheless, it is possible to sustain the dynamic response at a fairly high level, while keeping the leakage of the pilot stage at an acceptable level.

  20. Transapical Mitral Valve-in-Valve Replacement in Patient With Previous Complex Sternal Reconstruction.

    Science.gov (United States)

    Hynes, Conor F; Fatemi, Omid; Sharma, Aditya C; Nagy, Christian D; Trachiotis, Gregory D

    2016-01-01

    We present a complex case of a transapical redo mitral valve-in-valve replacement. Repeat mitral valve replacement was indicated for severe symptomatic bioprosthetic stenosis. In addition to the patient's numerous comorbidities that included diabetes, hepatic cirrhosis, ischemic cardiomyopathy, and atrial flutter, he had undergone a previous open mitral valve replacement that was complicated by sternal dehiscence requiring extensive chest wall reconstruction. Transapical approach was performed through left minithoracotomy incision with balloon-expandable valve. Transapical valve-in-valve replacement of a stenotic mitral bioprosthesis is a viable solution in a patient with previous complex chest wall reconstruction and multiple comorbidities.