Cover-gas-seal component development: dynamic inflatable-plug seal improvement

International Nuclear Information System (INIS)

Horton, P.H.

1977-01-01

This report documents the 1) radial compliance and 2) low friction coating tests conducted on the CRBRP Rotating Plug Inflatable Seals per test plan N707TR810014. Test results show that narrowing the seal blade from 0.25 to 0.12 in. will effectively reduce dynamic drag from 30 to 20 lb/ft under nominal conditions and will increase seal radial compliance from 0.12 to 0.30 in. without an unacceptable rise in dynamic drag. Tests also demonstrated that application of a teflon coating to the seal wear surface reduced breakaway drag by 25% based on results of comparison dwells

Superior sealing effect of hydroxyapatite in porous-coated implants

DEFF Research Database (Denmark)

Rahbek, Ole; Kold, Søren; Bendix, Knud

2005-01-01

Migration of wear debris to the periprosthetic bone is a major cause of osteolysis and implant failure. Both closed-pore porous coatings and hydroxyapatite (HA) coatings have been claimed to prevent the migration of wear debris. We investigated whether HA could augment the sealing effect of a por......Migration of wear debris to the periprosthetic bone is a major cause of osteolysis and implant failure. Both closed-pore porous coatings and hydroxyapatite (HA) coatings have been claimed to prevent the migration of wear debris. We investigated whether HA could augment the sealing effect...

Application study of magnetic fluid seal in hydraulic turbine

International Nuclear Information System (INIS)

Yu, Z Y; Zhang, W

2012-01-01

The waterpower resources of our country are abundant, and the hydroelectric power is developed, but at present the main shaft sealing device of hydraulic turbine is easy to wear and tear and the leakage is great. The magnetic fluid seal has the advantages of no contact, no wear, self-healing, long life and so on. In this paper, the magnetic fluid seal would be used in the main shaft of hydraulic turbine, the sealing structure was built the model, meshed the geometry, applied loads and solved by using MULTIPHYSICS in ANSYS software, the influence of the various sealing structural parameters such as tooth width, height, slot width, sealing gap on the sealing property were analyzed, the magnetic fluid sealing device suitable for large-diameter shaft and sealing water was designed, the sealing problem of the hydraulic turbine main shaft was solved effectively which will bring huge economic benefits.

Piston rod seal for a Stirling engine

Science.gov (United States)

Shapiro, Wilbur

1984-01-01

In a piston rod seal for a Stirling engine, a hydrostatic bearing and differential pressure regulating valve are utilized to provide for a low pressure differential across a rubbing seal between the hydrogen and oil so as to reduce wear on the seal.

Mechanical seal with textured sidewall

Energy Technology Data Exchange (ETDEWEB)

Khonsari, Michael M.; Xiao, Nian

2017-02-14

The present invention discloses a mating ring, a primary ring, and associated mechanical seal having superior heat transfer and wear characteristics. According to an exemplary embodiment of the present invention, one or more dimples are formed onto the cylindrical outer surface of a mating ring sidewall and/or a primary ring sidewall. A stationary mating ring for a mechanical seal assembly is disclosed. Such a mating ring comprises an annular body having a central axis and a sealing face, wherein a plurality of dimples are formed into the outer circumferential surface of the annular body such that the exposed circumferential surface area of the annular body is increased. The texture added to the sidewall of the mating ring yields superior heat transfer and wear characteristics.

Improved Main Shaft Seal Life in Gas Turbines Using Laser Surface Texturing

Science.gov (United States)

McNickle, Alan D.; Etsion, Izhak

2002-10-01

This paper presents a general overview of the improved main shaft seal life in gas turbines using laser surface texturing (LST). The contents include: 1) Laser Surface Texturing System; 2) Seal Schematic with LST applied; 3) Dynamic Rig Tests; 4) Surface Finish Definitions; 5) Wear Test Rig; 6) Dynamic Test Rig; 7) Seal Cross Section-Rig Test; and 8) Typical Test Results. This paper is in viewgraph form.

Enclosed mechanical seal face design for brittle materials copyright

International Nuclear Information System (INIS)

Marsi, J.A.

1994-01-01

Metal carbides are widely used as seal face material due to their hardness and wear resistance. Silicon carbide (SiC) has excellent performance as a seal face material, but it is relatively brittle and may break due to accidental overloads outside the boundary of normal operating conditions. In mechanical seals for nuclear primary coolant pumps, the shattered SiC pieces can get into the reactor system and cause serious damage. The conventional method of containing an SiC seal face is to shrink-fit it in a holder, which may lead the seal designer to contend with unwanted seal face deflections. This paper presents a successful, tested design which does not rely on shrink-fits. 5 refs., 9 figs., 4 tabs

Differences in Ostomy Pouch Seal Leakage Occurrences Between North American and European Residents.

Science.gov (United States)

Fellows, Jane; Forest Lalande, Louise; Martins, Lina; Steen, Anne; Størling, Zenia M

The purpose of this study was to compare experiences and concerns about pouch seal leakage between persons with ostomies residing in North America (Canada and the United States) and Europe (United Kingdom, Netherlands, Sweden, Germany, Belgium, France, and Italy). Differences in reported pouch wear time and accessories used between the 2 groups were also examined. Secondary analysis of data from a cross-sectional study (Ostomy Life Study). Responses from persons residing in European countries (n = 1939) were compared with responses of 1387 individuals residing in North American countries. Persons with an ostomy completed a questionnaire that focused on 4 topics related to the daily use of an ostomy pouching system (pouch seal leakage, ballooning, appearance of pouching system such as color and size of the pouch and whether it is discrete under clothing, and coupling failure of 2-piece pouching systems). Pouch seal leakage was defined as stomal effluent seeping between the skin and the wafer of the ostomy pouching system. Statistical analysis was performed using a proportional odds model including various variable effects. Special attention was given to frequency of pouch seal leakage occurrences. All tests were 2-sided; P values ≤.05 were deemed statistically significant. Participants living in the North American countries indicated they were more likely to experience leakage from the ostomy (odds ratio = 2.610, 95% CI 2.187-3.115; P < .0001). Findings also indicated they were more likely to worry about pouch seal leakage than those in the European countries' data set (odds ratio = 2.722, 95% CI 2.283-3.246; P < .0001). Participants residing in the North American countries had significantly longer wear times than those participants in the European countries (P < .0001, χ test). The use of accessories was associated with a longer pouching system wear time. Study results suggest that participants from the North American countries indicated significantly more

Application of radioisotope technique for investigation of pumps seals

International Nuclear Information System (INIS)

Antoszewski, B.; Zorawska, A.

1988-01-01

Radioisotope method of measuring the wear of rings of the face mechanical seals, bush in soft seals, and leakage in double mechanical seals is described. The examples are given. It is found that radioisotope technique can be used for investigation of the seals. (author)

Refrigeration system with clearance seals

International Nuclear Information System (INIS)

Holland, N. J.

1985-01-01

In a refrigeration system such as a split Stirling system, fluid seals associated with the reciprocating displacer are virtually dragless clearance seals. Movement of the displacer relative to the pressure variations in the working volume of gas is retarded by a discrete braking element. Because it is not necessary that the brake providing any sealing action, the brake can be designed for greater durability and less dependence on ambient and operating temperatures. Similarly, the clearance seal can be formed of elements having low thermal expansion such that the seal is not temperature dependent. In the primary embodiments the braking element is a split friction brake

Ultrasonic dip seal maintenance system

International Nuclear Information System (INIS)

Poindexter, A.M.; Ricks, H.E.

1978-01-01

Disclosed is a system for removing impurities from the surfaces of liquid dip seals and for wetting the metal surfaces of liquid dip seals in nuclear components. The system comprises an ultrasonic transducer that transmits ultrasonic vibrations along an ultrasonic probe to the metal and liquid surfaces of the dip seal thereby loosening and removing those impurities

Research on seal control systems for international nuclear safeguard and the vulnerability assessment on the seals

International Nuclear Information System (INIS)

Zhang Hongjian; Liu Tianshu; Cao Fangfang; Xu Chunyan

2014-01-01

Safeguard seals, also called Tamper-indicating devices (TIDs), are widely used to detect tampering or unauthorized entry in the international safeguard and security systems, Seal control systems consist of seal implementing plan, seal development and the vulnerability assessment on tbe seals, effective implementing procedures and methods of the seals. The vulnerability assessment contents of safeguard seals, thermo-shrinked film seals being as an example, and seals control systems in the implementation program are researched. The seal control systems discuss task assignment, seals management flow and seals program data flow to promote applying effectively seals. The vulnerability assessment program of seals studies assurance level to some different tampering techniques and measures. The researches must promote utilizing seals effectively for nuclear security, non-proliferation of nuclear weapons, radioactive waste management, and the nuclear material accounting and control. (authors)

Shaft seal assembly and method

Science.gov (United States)

Keba, John E. (Inventor)

2007-01-01

A pressure-actuated shaft seal assembly and associated method for controlling the flow of fluid adjacent a rotatable shaft are provided. The seal assembly includes one or more seal members that can be adjusted between open and closed positions, for example, according to the rotational speed of the shaft. For example, the seal member can be configured to be adjusted according to a radial pressure differential in a fluid that varies with the rotational speed of the shaft. In addition, in the closed position, each seal member can contact a rotatable member connected to the shaft to form a seal with the rotatable member and prevent fluid from flowing through the assembly. Thus, the seal can be closed at low speeds of operation and opened at high speeds of operation, thereby reducing the heat and wear in the seal assembly while maintaining a sufficient seal during all speeds of operation.

Design and development of face seal type sealing plug for advanced heavy water reactor

International Nuclear Information System (INIS)

Bansal, S.; Bhattacharyya, S.; Patel, R.J.; Agrawal, R.G.; Vaze, K.K.

2005-09-01

Advanced Heavy Water Reactor is a vertical pressure tube type reactor having light water as its coolant and heavy water as moderator. Sealing plug is required to close the pressure boundary of main heat transport system of the reactor by preventing escape of light water/steam From the coolant channel. There are 452 coolant channels in the reactor located in square lattice pitch. Sealing plug is located at the top of each coolant channel (in the top end fitting). Top end fitting is having a stepped bore to create a sealing face. Sealing plug is held through its expanded jaws in a specially provided groove of the end fitting. The plug was designed and prototypes were manufactured considering its functional importance, intricate design and precision machining requirements. Sealing plug consists of about 20 components mostly made up of precipitation hardening stainless steel, which is suitable for water environment and meets other requirements of strength and resistance to wear and galling. Seal disc is a critical component of the sealing plug as it is the pressure-retaining component. It is a circular disc with protruded stem. One face of the seal disc is nickel plated in the peripheral area that creates the sealing by abutting against the sealing face provided in the end fitting. The typical shape and profile of seal disc provides flexibility and allows elastic deformation to assist in locking of sealing plug and creating adequate seating force for effective sealing. Design and development aspects of the sealing plug have been detailed out in this report. Also results of stress analysis and experimental studies for seal disc have been mentioned in the report. Stress analysis and experimental testing was required for the seal disc because high stresses are developed due to its exposure to high pressure and temperature environment of Main Heat Transport system. Hot testing was carried out to simulate the reactor-simulated condition. The performance was found to be

Development of a magnetic fluid shaft seal for an axial-flow blood pump.

Science.gov (United States)

Sekine, Kazumitsu; Mitamura, Yoshinori; Murabayashi, Shun; Nishimura, Ikuya; Yozu, Ryouhei; Kim, Dong-Wook

2003-10-01

A rotating impeller in a rotary blood pump requires a supporting system in blood, such as a pivot bearing or magnetic suspension. To solve potential problems such as abrasive wear and complexity of a supporting system, a magnetic fluid seal was developed for use in an axial-flow blood pump. Sealing pressures at motor speeds of up to 8,000 rpm were measured with the seal immersed in water or bovine blood. The sealing pressure was about 200 mm Hg in water and blood. The calculated theoretical sealing pressure was about 230 mm Hg. The seal remained perfect for 743 days in a static condition and for 180+ days (ongoing test) at a motor speed of 7,000 rpm. Results of measurement of cell growth activity indicated that the magnetic fluid has no negative cytological effects. The specially designed magnetic fluid shaft seal is useful for an axial-flow blood pump.

Design study of shaft face seal with self-acting lift augmentation. 5: Performance in simulated gas turbine engine operation

Science.gov (United States)

Ludwig, L. P.; Johnson, R. L.

1971-01-01

The feasibility and the noncontact operation of the self-acting seal was demonstrated over a range of simulated gas turbine engine conditions from 200 to 500 ft/sec sliding speed. Sealed pressure differentials were 50 to 300 psi and sealed temperatures were 150 to 1200 F. Low leakage (about 1/10 that of conventional labyrinth seals) was exhibited in two endurance runs (200 and 338 hr) at 400 ft/sec, 200 psi and 1000 F (gas temperature). For these endurance runs, the self-acting pad wear was less than 3.8 micrometers (0.00015 in.); this low wear was attributed to the noncontact operation of the primary seal. Operating problems identified were fretting wear of the secondary seal and erosion of the primary seal by hard particles.

Does the seal licensing system in Scotland have a negative impact on seal welfare?

Directory of Open Access Journals (Sweden)

Laetitia Nunny

2016-08-01

Full Text Available This study examined the licensing system that permits seal shooting in Scotland, which was established under Part 6 Conservation of Seals of the Marine (Scotland Act 2010. Four approaches were used: data were collated and analyzed from both the Scottish Government and Scottish Marine Animal Stranding Scheme; a survey was sent to current license holders and informal interviews were conducted with key stakeholder types. Between February 2011 and the end of October 2015, 1229 gray seals and 275 common seals were reported shot under license to the Scottish Government. The numbers of seals reported as shot has reduced year-on-year since the licensing system was put in place. While some license holders, notably fish farms, were using some non-lethal forms of deterrent to reduce seal-related damage, these were often used alongside seal shooting. Of the seals reported as shot to the Scottish Government, only a small percentage were also reported to the Scottish Marine Animal Stranding Scheme, despite this being a licensing requirement. Only 2.3% of the shot gray seals and 4.5% of the shot common seals were necropsied. There is evidence from these necropsies that some seals had not died instantly or had not been shot in the manner recommended by the Scottish Seal Management Code of Practice. These preliminary results show that more carcasses need to be recovered and necropsied if the welfare implications of current seal shooting practice are to be properly assessed. The current legislation does not specify closed seasons to protect breeding seals and thirty-five per cent of necropsied seals were pregnant gray seals. Seals have also been shot during their lactation periods when pups are dependent on their mothers. This raises significant welfare concerns. The re-introduction of closed seasons specific to each species of seal is recommended along with greater effort to deploy non-lethal methods. Independent assessment of the number of seals being killed

Airfoil seal system for gas turbine engine

Science.gov (United States)

None, None

2013-06-25

A turbine airfoil seal system of a turbine engine having a seal base with a plurality of seal strips extending therefrom for sealing gaps between rotational airfoils and adjacent stationary components. The seal strips may overlap each other and may be generally aligned with each other. The seal strips may flex during operation to further reduce the gap between the rotational airfoils and adjacent stationary components.

Development of Advanced Carbon Face Seals for Aircraft Engines

Science.gov (United States)

Falaleev, S. V.; Bondarchuk, P. V.; Tisarev, A. Yu

2018-01-01

Modern aircraft gas turbine engines require the development of seals which can operate for a long time with low leakages. The basic type of seals applied for gas turbine engine rotor supports is face seal. To meet the modern requirements of reliability, leak-tightness and weight, low-leakage gas-static and hydrodynamic seals have to be developed. Dry gas seals use both gas-static and hydrodynamic principles. In dry gas seals microgrooves are often used, which ensure the reverse injection of leakages in the sealed cavity. Authors have developed a calculation technique including the concept of coupled hydrodynamic, thermal and structural calculations. This technique allows to calculate the seal performance taking into account the forces of inertia, rupture of the lubricant layer and the real form of the gap. Authors have compared the efficiency of seals with different forms of microgrooves. Results of calculations show that seal with rectangular form of microgrooves has a little gap leading to both the contact of seal surfaces and the wear. Reversible microgrooves have a higher oil mass flow rate, whereas HST micro-grooves have good performance, but they are difficult to produce. Spiral microgrooves have both an acceptable leakages and a high stiffness of liquid layer that is important in terms of ensuring of sealing performance at vibration conditions. Therefore, the spiral grooves were chosen for the developed seal. Based on calculation results, geometric dimensions were chosen to ensure the reliability of the seal operation by creating a guaranteed liquid film, which eliminates the wear of the sealing surfaces. Seals designed were tested both at the test rig and in the engine.

Rapid Analyses of Polyetheretherketone Wear Characteristics by Accelerated Wear Testing with Microfabricated Surfaces for Artificial Joint Systems.

Science.gov (United States)

Su, Chen-Ying; Kuo, Chien-Wei; Fang, Hsu-Wei

2017-01-01

Wear particle-induced biological responses are the major factors resulting in the loosening and then failure of total joint arthroplasties. It is feasible to improve the lubrication and reduce the wear of artificial joint system. Polyetheretherketone (PEEK) is considered as a potential bearing material due to its mechanical characteristics of resistance to fatigue strain. The PEEK wear particles have been indicated to be involved in biological responses in vitro, and further studies regarding the wear phenomena and wear particle generation are needed. In this study, we have established an accelerated wear testing system with microfabricated surfaces. Various contact pressures and lubricants have been utilized in the accelerated wear tests. Our results showed that increasing contact pressure resulted in an increase of wear particle sizes and wear rate, and the size of PEEK wear particles can be controlled by the feature size of microfabricated surfaces. These results provided the information rapidly about factors that affect the morphology and amount of PEEK wear particles and can be applied in the future for application of PEEK on the biological articulation system.

Pillow seal system at the BigRIPS separator

Energy Technology Data Exchange (ETDEWEB)

Tanaka, K., E-mail: ktanaka@riken.jp; Inabe, N.; Yoshida, K.; Kusaka, K.; Kubo, T.

2013-12-15

Highlights: • Pillow seal system has been installed for a high-intensity RI-beam facility at RIKEN. • It is aimed at facilitating remote maintenance under high residual radiation. • Local radiation shields are integrated with one of the pillow seals. • Pillow seals have been aligned to the beam axis within 1mm accuracy. • A leakage rate of 10{sup –9} Pa m{sup 3}/s has been achieved with our pillow seal system. -- Abstract: We have designed and installed a pillow seal system for the BigRIPS fragment separator at the RIKEN Radioactive Isotope Beam Factory (RIBF) to facilitate remote maintenance in a radioactive environment. The pillow seal system is a device to connect a vacuum chamber and a beam tube. It allows quick attachment and detachment of vacuum connections in the BigRIPS separator and consists of a double diaphragm with a differential pumping system. The leakage rate achieved with this system is as low as 10{sup –9} Pa m{sup 3}/s. We have also designed and installed a local radiation-shielding system, integrated with the pillow seal system, to protect the superconducting magnets and to reduce the heat load on the cryogenic system. We present an overview of the pillow seal and the local shielding systems.

Investigating the sealing capacity of a seal system in rock salt (DOPAS project)

Energy Technology Data Exchange (ETDEWEB)

Jantschik, Kyra; Moog, Helge C.; Czaikowski, Oliver; Wieczorek, Klaus [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) gGmbH, Braunschweig (Germany)

2016-11-15

This paper describes research and development work on plugging and sealing repositories, an issue of fundamental importance for the rock salt option which represents one of the three European repository options, besides the clay rock and the crystalline rock options. The programme aims at providing experimental data needed for the theoretical analysis of the long-term sealing capacity of concrete- based sealing materials. In order to demonstrate hydro-mechanical material stability under representative load scenarios, a comprehensive laboratory testing programme is carried out. This comprises investigation of the sealing capacity of the combined seal system and impact of the so-called excavation-damaged zones (EDZ) as well as investigation of the hydro-chemical long-term stability of the seal in contact with different brines under diffusive and advective conditions. This paper presents experimental approaches and preliminary results from laboratory investigations on salt concrete and combined systems as obtained to date.

Severe service sealing solutions

International Nuclear Information System (INIS)

Metcalfe, R.; Wensel, R.

1994-09-01

Successful sealing usually requires much more than initial leak-tightness. Friction and wear must also be acceptable, requiring a good understanding of tribology at the sealing interface. This paper describes various sealing solutions for severe service conditions. The CAN2A and CAN8 rotary face seals use tungsten carbide against carbon-graphite to achieve low leakage and long lifetime in nuclear main coolant pumps. The smaller CAN6 seal successfully uses tungsten carbide against silicon carbide in reactor water cleanup pump service. Where friction in CANDU fuelling machine rams must be essentially zero, a hydrostatic seal using two silicon carbide faces is the solution. In the NRU reactor moderator pumps, where pressure is much lower, eccentric seals that prevent boiling at the seal faces are giving excellent service. All these rotary face seals rely on supplementary elastomer seals between their parts. An integrated engineering approach to high performance sealing with O-rings is described. This is epitomized in critical Space Shuttle applications, but is increasingly being applied in CANDU plants. It includes gland design, selection and qualification of material, quality assurance, detection of defects and the effects of lubrication, surface finish, squeeze, stretch and volume constraints. In conclusion, for the severe service applications described, customized solutions have more than paid for themselves by higher reliability, lower maintenance requirements and reduced outage time. (author)

Mechanical seal having a double-tier mating ring

Science.gov (United States)

Khonsari, Michael M.; Somanchi, Anoop K.

2005-09-13

An apparatus and method to enhance the overall performance of mechanical seals in one of the following ways: by reducing seal face wear, by reducing the contact surface temperature, or by increasing the life span of mechanical seals. The apparatus is a mechanical seal (e.g., single mechanical seals, double mechanical seals, tandem mechanical seals, bellows, pusher mechanical seals, and all types of rotating and reciprocating machines) comprising a rotating ring and a double-tier mating ring. In a preferred embodiment, the double-tier mating ring comprises a first and a second stationary ring that together form an agitation-inducing, guided flow channel to allow for the removal of heat generated at the seal face of the mating ring by channeling a coolant entering the mating ring to a position adjacent to and in close proximity with the interior surface area of the seal face of the mating ring.

Active bypass flow control for a seal in a gas turbine engine

Science.gov (United States)

Ebert, Todd A.; Kimmel, Keith D.

2017-01-10

An active bypass flow control system for controlling bypass compressed air based upon leakage flow of compressed air flowing past an outer balance seal between a stator and rotor of a first stage of a gas turbine in a gas turbine engine is disclosed. The active bypass flow control system is an adjustable system in which one or more metering devices may be used to control the flow of bypass compressed air as the flow of compressed air past the outer balance seal changes over time as the outer balance seal between the rim cavity and the cooling cavity wears. In at least one embodiment, the metering device may include a valve formed from one or more pins movable between open and closed positions in which the one pin at least partially bisects the bypass channel to regulate flow.

Test of Seal System for Flexible Pipe End Fitting

DEFF Research Database (Denmark)

Banke, Lars; Jensen, Thomas Gregers

1999-01-01

The purpose of the end fitting seal system is to ensure leak proof termination of flexible pipes. The seal system of an NKT end fitting normally consists of a number of ring joint gaskets mounted in a steel sleeve on the outside of the polymeric inner liner of the pipe. The seal system is activated...... by compression of the gaskets, thus using the geometry to establish a seal towards the inner liner of the pipe and the steel sleeve of the end fitting. This paper describes how the seal system of an end fitting can be tested using an autoclave. By regulating temperature and pressure, the seal system can...... be tested up to 130oC and 51.7 MPa. Pressure, temperature and the mechanical behaviours of the pipe are measured for use in further research. The set-up is used to test the efficiency of the seal system as function of parameters such as cross sectional shapes of the gaskets, tolerances between gaskets...

Application of hydrophilic magnetic fluid to oil seal

Science.gov (United States)

Kim, Y. S.; Nakatsuka, K.; Fujita, T.; Atarashi, T.

1999-07-01

Bearing and gear are important components in machines. Lubricant for bearing or gear is usually confined in working space by rubber retainer or mechanical seal, and its lifetime which is determined by the friction wear of sealing material is important. In this report, the basic characteristics of magnetic fluid seal applied to lubricant retainer is studied. The fluid used for this purpose is ethyleneglycol-based magnetic fluid in which silica-coated iron particles are dispersed. The lubricant oil seal set consisting of six stages of pole piece and Nd-permanent magnets (4.0 Wb/m 2) in seal housing showed an excellent pressure resistance of 618 kPa under a rotating speed of 1800 rpm.

Nanocrystalline diamond coatings for mechanical seals applications.

Science.gov (United States)

Santos, J A; Neto, V F; Ruch, D; Grácio, J

2012-08-01

A mechanical seal is a type of seal used in rotating equipment, such as pumps and compressors. It consists of a mechanism that assists the connection of the rotating shaft to the housings of the equipments, preventing leakage or avoiding contamination. A common cause of failure of these devices is end face wear out, thus the use of a hard, smooth and wear resistant coating such as nanocrystalline diamond would be of great importance to improve their working performance and increase their lifetime. In this paper, different diamond coatings were deposited by the HFCVD process, using different deposition conditions. Additionally, the as-grown films were characterized for, quality, morphology and microstructure using scanning electron microscopy (SEM) and Raman spectroscopy. The topography and the roughness of the films were characterized by atomic force microscopy (AFM).

Application of a magnetic fluid seal to rotary blood pumps

International Nuclear Information System (INIS)

Mitamura, Y; Arioka, S; Azegami, M; Sakota, D; Sekine, K

2008-01-01

A magnetic fluid seal enables mechanical contact-free rotation of a shaft without frictional heat and material wear and hence has excellent durability. However, the durability of a magnetic fluid seal decreases in liquid. The life of a seal applied to a rotary blood pump is not known. We have developed a magnetic fluid seal that has a shield mechanism minimizing the influence of the rotary pump on the magnetic fluid. The developed magnetic fluid seal worked for over 286 days in a continuous flow condition, for 24 days (on-going) in a pulsatile flow condition and for 24 h (electively terminated) in blood flow. The magnetic fluid seal is promising as a shaft seal for rotary blood pumps

Valve seat pores sealed with thermosetting monomer

Science.gov (United States)

Olmore, A. B.

1966-01-01

Hard anodic coating provides a smooth wear resistant value seating surface on a cast aluminum alloy valve body. Vacuum impregnation with a thermosetting monomer, diallyl phthalate, seals the pores on the coating to prevent galvanic corrosion.

Seals and sealing handbook

CERN Document Server

Flitney, Robert K

2014-01-01

Seals and Sealing Handbook, 6th Edition provides comprehensive coverage of sealing technology, bringing together information on all aspects of this area to enable you to make the right sealing choice. This includes detailed coverage on the seals applicable to static, rotary and reciprocating applications, the best materials to use in your sealing systems, and the legislature and regulations that may impact your sealing choices. Updated in line with current trends this updated reference provides the theory necessary for you to select the most appropriate seals for the job and with its 'Failur

Development of counting system for wear measurements using Thin Layer Activation and the Wearing Apparatus

Energy Technology Data Exchange (ETDEWEB)

França, Michel de A.; Suita, Julio C.; Salgado, César M., E-mail: mchldante@gmail.com, E-mail: suita@ien.gov.br, E-mail: otero@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2017-07-01

This paper focus on developing a counting system for the Wearing Apparatus, which is a device previously built to generate measurable wear on a given surface (Main Source) and to carry the fillings from it to a filter (second source). The Thin Layer Activation is a technique used to produce activity on one of the Wearing Apparatus' piece, this activity is proportional to the amount of material worn, or scrapped, from the piece's surface. Thus, by measuring the activity on those two points it is possible to measure the produced wear. The methodology used in this work is based on simulations through MCNP-X Code to nd the best specifications for shielding, solid angles, detectors dimensions and collimation for the Counting System. By simulating several scenarios, each one different from the other, and analyzing the results in the form of Counts Per Second, the ideal counting system's specifications and geometry to measure the activity in the Main Source and the Filter (second source) is chosen. After that, a set of previously activated stainless steel foils were used to reproduce the real experiments' conditions, this real experiment consists of using TLA and the Wearing Apparatus, the results demonstrate that the counting system and methodology are adequate for such experiments. (author)

Wear Analysis of Top Piston Ring to Reduce Top Ring Reversal Bore Wear

Directory of Open Access Journals (Sweden)

P. Ilanthirayan

2017-12-01

Full Text Available The piston rings are the most important part in engine which controls the lubricating oil consumption and blowby of the gases. The lubricating film of oil is provided to seal of gases towards crankcase and also to give smooth friction free translatory motion between rings and liner. Of the three rings present top ring is more crucial as it does the main work of restricting gases downwards the crankcase. Boundary lubrication is present at the Top dead centre (TDC and Bottom dead centre (BDC of the liner surface. In addition to this, top ring is exposed to high temperature gases which makes the oil present near the top ring to get evaporated and decreasing its viscosity, making metal-metal contact most of the time. Due to this at TDC, excess wear happens on the liner which is termed as Top ring reversal bore wear. The wear rate depends upon many parameters such as lubrication condition, viscosity index, contact type, normal forces acting on ring, geometry of ring face, surface roughness, material property. The present work explores the wear depth for different geometries of barrel ring using Finite Element model with the help of Archard wear law and the same is validated through experimentation. The study reveals that Asymmetric barrel rings have less contact pressure which in turn reduces the wear at Top dead centre.

Active bypass flow control for a seal in a gas turbine engine

Science.gov (United States)

Ebert, Todd A.; Kimmel, Keith D.

2017-03-14

An active bypass flow control system for controlling bypass compressed air based upon leakage flow of compressed air flowing past an outer balance seal between a stator and rotor of a first stage of a gas turbine in a gas turbine engine is disclosed. The active bypass flow control system is an adjustable system in which one or more metering devices may be used to control the flow of bypass compressed air as the flow of compressed air past the outer balance seal changes over time as the outer balance seal between the rim cavity and the cooling cavity wears In at least one embodiment, the metering device may include an annular ring having at least one metering orifice extending therethrough, whereby alignment of the metering orifice with the outlet may be adjustable to change a cross-sectional area of an opening of aligned portions of the outlet and the metering orifice.

Upgrading primary heat transport pump seals

International Nuclear Information System (INIS)

Graham, T.; Metcalfe, R.; Rhodes, D.; McInnes, D.

1995-01-01

Changes in the operating environment at the Bruce-A Nuclear Generating Station created the need for an upgraded Primary Heat Transport Pump (PHTP) seal. In particular, the requirement for low pressure running during more frequent start-ups exposed a weakness of the CAN2 seal and reduced its reliability. The primary concern at Bruce-A was the rotation of the CAN2 No. 2 stators in their holders. The introduction of low pressure running exacerbated this problem, giving rapid wear of the stator back face, overheating, and thermocracking. In addition, the resulting increase in friction between the stator and its holder increased stationary-side hysteresis and thereby changed the seal characteristic to the point where interseal pressure oscillations became prevalent. The resultant increased hysteresis also led to hard rubbing of the seal faces during temperature transients. An upgraded seal was required for improved reliability to avoid forced outages and to reduce maintenance costs. This paper describes this upgraded 'replacement seal' and its performance history. In spite of the 'teething' problems detailed in this paper, there have been no forced outages due to the replacement seal, and in the words of a seal maintenance worker at Bruce-A, 'it allows me to go home and sleep at night instead of worrying about seal failures.' (author)

Long-term brine migration through an engineered shaft seal system

International Nuclear Information System (INIS)

Fryar, D.G.; Beach, J.A.; Kelley, V.A.; Knowles, M.K.

1997-01-01

The shaft seal system for the Waste Isolation Pilot Plant (WIPP) must provide a barrier to the migration of fluids within the shafts to prevent the release of contaminants to the accessible environment. To investigate the performance of the shaft seal system, a set of fluid flow performance models was developed based upon the physical characteristics of the WIPP shaft seal system and the surrounding geologic media. This paper describes the results of a numerical model used to investigate the long-term potential for brine migration through the shaft seal system. Modeling results demonstrate that the WIPP shaft seal system will effectively limit brine migration within the repository shafts

2005 NASA Seal/Secondary Air System Workshop, Volume 1

Science.gov (United States)

Steinetz, Bruce M. (Editor); Hendricks, Robert C. (Editor)

2006-01-01

The 2005 NASA Seal/Secondary Air System workshop covered the following topics: (i) Overview of NASA s new Exploration Initiative program aimed at exploring the Moon, Mars, and beyond; (ii) Overview of the NASA-sponsored Propulsion 21 Project; (iii) Overview of NASA Glenn s seal project aimed at developing advanced seals for NASA s turbomachinery, space, and reentry vehicle needs; (iv) Reviews of NASA prime contractor, vendor, and university advanced sealing concepts including tip clearance control, test results, experimental facilities, and numerical predictions; and (v) Reviews of material development programs relevant to advanced seals development. Turbine engine studies have shown that reducing high-pressure turbine (HPT) blade tip clearances will reduce fuel burn, lower emissions, retain exhaust gas temperature margin, and increase range. Several organizations presented development efforts aimed at developing faster clearance control systems and associated technology to meet future engine needs. The workshop also covered several programs NASA is funding to develop technologies for the Exploration Initiative and advanced reusable space vehicle technologies. NASA plans on developing an advanced docking and berthing system that would permit any vehicle to dock to any on-orbit station or vehicle. Seal technical challenges (including space environments, temperature variation, and seal-on-seal operation) as well as plans to develop the necessary "androgynous" seal technologies were reviewed. Researchers also reviewed tests completed for the shuttle main landing gear door seals.

Magnetic nanofluids and magnetic composite fluids in rotating seal systems

International Nuclear Information System (INIS)

Borbath, T; Borbath, I; Boros, T; Bica, D; Vekas, L; Potencz, I

2010-01-01

Recent results are presented concerning the development of magnetofluidic leakage-free rotating seals for vacuum and high pressure gases, evidencing significant advantages compared to mechanical seals. The micro-pilot scale production of various types of magnetizable sealing fluids is shortly reviewed, in particular the main steps of the chemical synthesis of magnetic nanofluids and magnetic composite fluids with light hydrocarbon, mineral oil and synthetic oil carrier liquids. The behavior of different types of magnetizable fluids in the rotating sealing systems is analyzed. Design concepts, some constructive details and testing procedures of magnetofluidic rotating seals are presented such as the testing equipment. The main characteristics of several magnetofluidic sealing systems and their applications will be presented: vacuum deposition systems and liquefied gas pumps applications, mechanical and magnetic nanofluid combined seals, gas valves up to 40 bar equipped by rotating seal with magnetic nanofluids and magnetic composite fluids.

Cask systems development program seal technology

International Nuclear Information System (INIS)

Madsen, M.M.; Humphreys, D.L.; Edwards, K.R.

1991-01-01

General design or test performance requirements for radioactive materials (RAM) packages are specified in Title 10 of the US Code of Federal Regulations Part 71 (10 CFR 71). Seals that provide the containment system interface between the packaging body and the closure must function in both high- and low-temperature environments under dynamic and static conditions. Experiments were performed to characterize the performance of several seal materials at low temperatures. Helium leak tests on face seals were used to compare the materials. Materials tested include butyl, neoprene, ethylene propylene, fluorosilicone, silicone, Eypel, Kalrez, Teflon, fluorocarbon, and Teflon/silicone composites. Results show that the seal materials tested, with the exception of silicone S613-60, are not leak tight (1 x 10 -7 std cm 3 /s) at manufacturer low-temperature ratings

Method and system to facilitate sealing in gas turbines

Science.gov (United States)

Morgan, Victor John; Foster, Gregory Thomas; Sarawate, Neelesh Nandkumar

2017-09-12

A method and system for sealing between components within a gas turbine is provided. A first recess defined in a first component receives a seal member. A second recess defined in a second component adjacent the first component also receives the seal member. The first and second recesses are located proximate a hot gas path defined through the gas turbine, and define circumferential paths about the turbine axis. The seal member includes a sealing face that extends in a direction substantially parallel to the turbine axis. The seal member also includes a plurality of seal layers, wherein at least one of the seal layers includes at least one stress relief region for facilitating flexing of the first seal member.

Dynamic Characteristics of Flow Induced Vibration in a Rotor-Seal System

Directory of Open Access Journals (Sweden)

Nan Zhang

2011-01-01

Full Text Available Flow induced vibration is an important factor affecting the performance of the rotor-seal system. From the point of view of flow induced vibration, the nonlinear models of the rotor-seal system are presented for the analysis of the fluid force, which is induced by the interaction between the unstable fluid flow in the seal and the vibrating rotor. The nonlinear characteristics of flow induced vibration in the rotor-seal system are analyzed, and the nonlinear phenomena in the unbalanced rotor-seal system are investigated using the nonlinear models. Various nonlinear phenomena of flow induced vibration in the rotor-seal system, such as synchronization phenomenon and amplitude mutation, are reproduced.

Comparison of results of experimental research with numerical calculations of a model one-sided seal

Directory of Open Access Journals (Sweden)

Joachimiak Damian

2015-06-01

Full Text Available Paper presents the results of experimental and numerical research of a model segment of a labyrinth seal for a different wear level. The analysis covers the extent of leakage and distribution of static pressure in the seal chambers and the planes upstream and downstream of the segment. The measurement data have been compared with the results of numerical calculations obtained using commercial software. Based on the flow conditions occurring in the area subjected to calculations, the size of the mesh defined by parameter y+ has been analyzed and the selection of the turbulence model has been described. The numerical calculations were based on the measurable thermodynamic parameters in the seal segments of steam turbines. The work contains a comparison of the mass flow and distribution of static pressure in the seal chambers obtained during the measurement and calculated numerically in a model segment of the seal of different level of wear.

High-Pressure Hot-Gas Self-Acting Floating Ring Shaft Seal for Liquid Rocket Turbopumps. [tapered bore seals

Science.gov (United States)

Burcham, R. E.; Diamond, W. A.

1980-01-01

Design analysis, detail design, fabrication, and experimental evaluation was performed on two self acting floating ring shaft seals for a rocket engine turbopump high pressure 24132500 n/sq m (3500 psig) hot gas 533 K 9500 F) high speed 3142 rad/sec (30000 rmp) turbine. The initial design used Rayleigh step hydrodynamic lift pads to assist in centering the seal ring with minimum rubbing contact. The final design used a convergent tapered bore to provide hydrostatic centering force. The Rayleigh step design was tested for 107 starts and 4.52 hours total. The leakage was satisfactory; however, the design was not acceptable due to excessive wear caused by inadequate centering force and failure of the sealing dam caused by erosion damage. The tapered bore design was tested for 370 starts and 15.93 hours total. Satisfactory performance for the required life of 7.5 hours per seal was successfully demonstrated.

Floating seal system for rotary devices

Science.gov (United States)

Banasiuk, H.A.

1983-08-23

This invention relates to a floating seal system for rotary devices to reduce gas leakage around the rotary device in a duct and across the face of the rotary device to an adjacent duct. The peripheral seal bodies are made of resilient material having a generally U-shaped cross section wherein one of the legs is secured to a support member and the other of the legs forms a contacting seal against the rotary device. The legs of the peripheral seal form an extended angle of intersection of about 10[degree] to about 30[degree] in the unloaded condition to provide even sealing forces around the periphery of the rotary device. The peripheral seal extends around the periphery of the support member except where intersected by radial seals which reduce gas leakage across the face of the rotary device and between adjacent duct portions. The radial seal assembly is fabricated from channel bars, the smaller channel bar being secured to the divider of the support member and a larger inverted rigid floating channel bar having its legs freely movable over the legs of the smaller channel bar forming therewith a tubular channel. A resilient flexible tube is positioned within the tubular channel for substantially its full length to reduce gas leakage across the tubular channel. A spacer extends beyond the face of the floating channel near each end of the floating channel a distance to provide desired clearance between the floating channel and the face of the rotary device. 5 figs.

An Automatic Assembling System for Sealing Rings Based on Machine Vision

Directory of Open Access Journals (Sweden)

Mingyu Gao

2017-01-01

Full Text Available In order to grab and place the sealing rings of battery lid quickly and accurately, an automatic assembling system for sealing rings based on machine vision is developed in this paper. The whole system is composed of the light sources, cameras, industrial control units, and a 4-degree-of-freedom industrial robot. Specifically, the sealing rings are recognized and located automatically with the machine vision module. Then industrial robot is controlled for grabbing the sealing rings dynamically under the joint work of multiple control units and visual feedback. Furthermore, the coordinates of the fast-moving battery lid are tracked by the machine vision module. Finally the sealing rings are placed on the sealing ports of battery lid accurately and automatically. Experimental results demonstrate that the proposed system can grab the sealing rings and place them on the sealing port of the fast-moving battery lid successfully. More importantly, the proposed system can improve the efficiency of the battery production line obviously.

The cool seal system: a practical solution to the shaft seal problem and heat related complications with implantable rotary blood pumps.

Science.gov (United States)

Yamazaki, K; Mori, T; Tomioka, J; Litwak, P; Antaki, J F; Tagusari, O; Koyanagi, H; Griffith, B P; Kormos, R L

1997-01-01

A critical issue facing the development of an implantable, rotary blood pump is the maintenance of an effective seal at the rotating shaft. Mechanical seals are the most versatile type of seal in wide industrial applications. However, in a rotary blood pump, typical seal life is much shorter than required for chronic support. Seal failure is related to adhesion and aggregation of heat denatured blood proteins that diffuse into the lubricating film between seal faces. Among the blood proteins, fibrinogen plays an important role due to its strong propensity for adhesion and low transition temperature (approximately 50 degrees C). Once exposed to temperature exceeding 50 degrees C, fibrinogen molecules fuse together by multi-attachment between heat denatured D-domains. This quasi-polymerized fibrin increases the frictional heat, which proliferates the process into seal failure. If the temperature of the seal faces is maintained well below 50 degrees C, a mechanical seal would not fail in blood. Based on this "Cool-Seal" concept, we developed a miniature mechanical seal made of highly thermally conductive material (SiC), combined with a recirculating purge system. A large supply of purge fluid is recirculated behind the seal face to augment convective heat transfer to maintain the seal temperature below 40 degrees C. It also cools all heat generating pump parts (motor coil, bearing, seal). The purge consumption has been optimized to virtually nil (seal system has now been incorporated into our intraventricular axial flow blood pump (IVAP) and newly designed centrifugal pump. Ongoing in vivo evaluation of these systems has demonstrated good seal integrity for more than 160 days. The Cool-Seal system can be applied to any type of rotary blood pump (axial, diagonal, centrifugal, etc.) and offers a practical solution to the shaft seal problem and heat related complications, which currently limit the use of implantable rotary blood pumps.

Thermo-Mechanical Test of Seal System in Flexible Pipe End Fittings

DEFF Research Database (Denmark)

Banke, Lars

1999-01-01

are driven radially into the barrier layer and supported by the surrounding steel casing. In order to verify the integrity of the concept the seal system is subjected cyclic pressure and temperature variations to simulate the service conditions.The aim of the testing is to demonstrate the sensitivity...... of the seal system geometry and its tolerances necessary to maintain a tight seal. The test is carried out in a purpose built autoclave, in which the seal system can be tested while undergoing variations in pressure and temperature.The paper will present a study on the importance of the geometry of the gasket...... and the inner liner. The inner and outer diameter of the gasket are varied to see the effectiveness of the seal mechanism. The effect of varying the width of the gasket as well as the surface roughness of the components in the seal system is analysed. Finally, it is investigated how the seal system is affected...

Testing of improved polyimide actuator rod seals at high temperature and under vacuum conditions for use in advanced aircraft hydraulic systems

Science.gov (United States)

Sellereite, B. K.; Waterman, A. W.; Nelson, W. G.

1974-01-01

Polyimide second-stage rod seals were evaluated to determine their suitability for applications in space station environments. The 6.35-cm (2.5-in.)K-section seal was verified for thermal cycling operation between room temperature and 478 K (400 F) and for operation in a 133 micron PA(0.000001 mm Hg) vacuum environment. The test seal completed the scheduled 96 thermal cycles and 1438 hr in vacuum with external rod seal leakage well within the maximum allowable of two drops per 25 actuation cycles. At program completion, the seals showed no signs of structural degradation. Posttest inspection showed the seals retained a snug fit against the shaft and housing walls, indicating additional wear life capability. Evaluation of a molecular flow section during vacuum testing, to inhibit fluid loss through vaporization, showed it to be beneficial with MIL-H-5606, a petroleum-base fluid, in comparison with MIL-H-83282, a synthetic hydrocarbon-base fluid.

Dynamics of face seals for high speed turbomachinery

Science.gov (United States)

Leefe, Simon

1993-10-01

Face seals in rocket engine fuel and oxidizer turbopumps have been the subject of intense investigation for over 25 years. While advances have been made in the understanding of thin film lubrication between seal faces, valuable data has been produced on the friction and wear of material pairs in cryogenic environments; pioneering work has been done on the effect of lubricant phase change in seals, and many improvements have been made in mechanical seal design. Relatively superficial attention has been given to the vibrational dynamics of face seals in high-speed turbomachinery. BHR Group Ltd. (formerly BHRA) has recently completed the first stage of a study, commissioned by the European Space Agency, to investigate this area. This has involved the development of a two-dimensional adiabatic, turbulent lubrication model for thick gas film applications, the production of an integrated mathematical model of gas seal vibrational dynamics for thin film applications, implementation in software, the undertaking of an experimental program to validate software against variations in operating conditions and design variables, and suggestions for improved seal design.

High speed, self-acting shaft seal. [for use in turbine engines

Science.gov (United States)

Ludwig, L. P.; Hady, W. F. (Inventor)

1975-01-01

A high-speed, self-acting circumferential type shaft seal for use in turbine engines is disclosed. One or more conventional circumferential ring seals having a central aperture are mounted in a housing. In three of the four embodiments of the invention, a helical groove and one or more dam seals are cut in the inner cylindrical surface of the one or more ring seals. In a fourth embodiment, two or more lift pads are disposed in surface contact with the inner cylindrical surface of the seal rings. To the outside of the lift pads, two dam seals are cut in the inner cylindrical surface of two of the ring seals. In each of the embodiments, a net outward radial force was produced during rotation of the turbine causing the ring seals to lift out of contact with the turbine shaft to minimize wear of the ring seals.

High speed, self-acting, face-contact shaft seal has low leakage and very low wear

Science.gov (United States)

Zuk, J.; Ludwig, L. P.; Johnson, R. L.

1972-01-01

Design adds gas thrust bearing to face of conventional face seal. Bearing lifts seal's carbon face out of contact after startup and establishes thin gas film between sealing surfaces. Operating pressure and speed capabilities are greater than those of conventional face seals.

Steam Turbine Flow Path Seals (a Review)

Science.gov (United States)

Neuimin, V. M.

2018-03-01

Various types of shroud, diaphragm, and end seals preventing idle leak of working steam are installed in the flow paths of steam turbine cylinders for improving their efficiency. Widely known labyrinth seals are most extensively used in the Russian turbine construction industry. The category of labyrinth seals also includes seals with honeycomb inserts. The developers of seals with honeycomb inserts state that the use of such seals makes it possible to achieve certain gain due to smaller leaks of working fluid and more reliable operation of the system under the conditions in which the rotor rotating parts may rub against the stator elements. However, a positive effect can only be achieved if the optimal design parameters of the honeycomb structure are fulfilled with due regard to the specific features of its manufacturing technology and provided that this structure is applied in a goal-seeking manner in the seals of steam and gas turbines and compressors without degrading their vibration stability. Calculated and preliminary assessments made by experts testify that the replacement of conventional labyrinth seals by seals with honeycomb inserts alone, due to which the radial gaps in the shroud seal can be decreased from 1.5 to 0.5 mm, allows the turbine cylinder efficiency to be increased at the initial stage by approximately 1% with the corresponding gain in the turbine set power output. The use of rectangular-cellular seals may result, according to estimates made by their developers, in a further improvement of turbine efficiency by 0.5-1.0%. The labor input required to fabricate such seals is six to eight times smaller than that to fabricate labyrinth seals with honeycomb inserts. Recent years have seen the turbine construction companies of the United States and Germany advertising the use of abradable (sealing) coatings (borrowed from the gas turbine construction technology) in the turbine designs instead of labyrinth seals. The most efficient performance of

Shaft/shaft-seal interface characteristics of a multiple disk centrifugal blood pump.

Science.gov (United States)

Manning, K B; Miller, G E

1999-06-01

A multiple disk centrifugal pump (MDCP) is under investigation as a potential left ventricular assist device. As is the case with most shaft driven pumps, leakage problems around the shaft/shaft seal interface are of major interest. If leakage were to occur during or after implantation, potential events such as blood loss, clotting, blood damage, and/or infections might result in adverse effects for the patient. Because these effects could be quite disastrous, potential shaft and shaft seal materials have been investigated to determine the most appropriate course to limit these effects. Teflon and nylon shaft seals were analyzed as potential candidates along with a stainless steel shaft and a Melonite coated shaft. The materials and shafts were evaluated under various time durations (15, 30, 45, and 60 min), motor speeds (800, 1,000, 1,200, and 1,400 rpm), and outer diameters (1/2 and 3/4 inches). The motor speed and geometrical configurations were typical for the MDCP under normal physiologic conditions. An air and water study was conducted to analyze the inner diameter wear, the inner temperature values, and the outer temperature values. Statistical comparisons were computed for the shaft seal materials, the shafts, and the outer diameters along with the inner and outer temperatures. The conclusions made from the results indicate that both the tested shaft seal materials and shaft materials are not ideal candidates to be used for the MDCP. Teflon experienced a significant amount of wear in air and water studies. Nylon did experience little wear, but heat generation was an evident problem. A water study on nylon was not conducted because of its molecular structure.

Study on Nonlinear Vibration and Crack Fault of Rotor-bearing-seal Coupling System

Directory of Open Access Journals (Sweden)

Yuegang LUO

2014-02-01

Full Text Available The nonlinear dynamic model of rotor-bearing-seal system with crack in shaft is set up based on the coupling model of nonlinear oil-film force and Muszyska’s nonlinear seal fluid force. The dynamic vibration characteristics of the rotor-bearing-seal system and the effects of physical and structural parameters of labyrinth seal and crack fault on movement character of the rotor were analyzed. The increases of seal length, seal pressure differential, seal radius and axial velocity are in favor of the stability of the system, and it of seal gap and crack depth are not in favor of the stability of the system.

2007 NASA Seal/Secondary Air System Workshop. Volume 1

Science.gov (United States)

Steinetz, Bruce M.; Hendricks, Robert C.; Delgado, Irebert

2008-01-01

The 2007 NASA Seal/Secondary Air System workshop covered the following topics: (i) Overview of NASA's new Orion project aimed at developing a new spacecraft that will fare astronauts to the International Space Station, the Moon, Mars, and beyond; (ii) Overview of NASA's fundamental aeronautics technology project; (iii) Overview of NASA Glenn s seal project aimed at developing advanced seals for NASA's turbomachinery, space, and reentry vehicle needs; (iv) Reviews of NASA prime contractor, vendor, and university advanced sealing concepts, test results, experimental facilities, and numerical predictions; and (v) Reviews of material development programs relevant to advanced seals development. Turbine engine studies have shown that reducing seal leakage as well as high-pressure turbine (HPT) blade tip clearances will reduce fuel burn, lower emissions, retain exhaust gas temperature margin, and increase range. Turbine seal development topics covered include a method for fast-acting HPT blade tip clearance control, noncontacting low-leakage seals, intershaft seals, and a review of engine seal performance requirements for current and future Army engine platforms.

Subscale hood seal test topical report

Energy Technology Data Exchange (ETDEWEB)

Versteeg, J.L.; Herold, B.A.; McClintic, J.K.; Schmall, R.A.; Hoetzl, M.

1991-09-06

To maximize the transfer of heat from the recirculated gases to the scrap, it is essential to percolate as much of the gases as possible through the scrap. To accomplish this flow path and avoid the bypassing of hot gas around the scrap, the seal between the preheater hood and the scrap bucket must be relatively tight. These tests which are described in this report were designed to measure the performance of several possible seal designs under simulated operating conditions. At the conclusion of the tests, one design was recommended as the primary arrangement with another design considered as an alternate. Both designs met the criteria of low leakage but one design was preferred due an expected greater resistance to wear. The test results also provided valuable information for estimating seal leakage in the full scale installation.

O-Ring sealing arrangements for ultra-high vacuum systems

Science.gov (United States)

Kim, Chang-Kyo; Flaherty, Robert

1981-01-01

An all metal reusable O-ring sealing arrangement for sealing two concentric tubes in an ultra-high vacuum system. An O-ring of a heat recoverable alloy such as Nitinol is concentrically positioned between protruding sealing rings of the concentric tubes. The O-ring is installed between the tubes while in a stressed martensitic state and is made to undergo a thermally induced transformation to an austenitic state. During the transformation the O-ring expands outwardly and contracts inwardly toward a previously sized austenitic configuration, thereby sealing against the protruding sealing rings of the concentric tubes.

Remote vacuum or pressure sealing device and method for critical isolated systems

Science.gov (United States)

Brock, James David [Newport News, VA; Keith, Christopher D [Newport News, VA

2012-07-10

A remote vacuum or pressure sealing apparatus and method for making a radiation tolerant, remotely prepared seal that maintains a vacuum or pressure tight seal throughout a wide temperature range. The remote sealing apparatus includes a fixed threaded sealing surface on an isolated system, a gasket, and an insert consisting of a plug with a protruding sample holder. An insert coupling device, provided for inserting samples within the isolated system, includes a threaded fastener for cooperating with the fixed threaded sealing surface on the isolated system. The insert coupling device includes a locating pin for azimuthal orientation, coupling pins, a tooted coaxial socket wrench, and an insert coupling actuator for actuating the coupling pins. The remote aspect of the sealing apparatus maintains the isolation of the system from the user's environment, safely preserving the user and the system from detrimental effect from each respectively.

Automated Image Acquisition System for the Verification of Copper-Brass Seal Images

International Nuclear Information System (INIS)

Stringa, E.; Bergonzi, C.; Littmann, F.; ); Marszalek, Y.; Tempesta, S.; )

2015-01-01

This paper describes a system for the verification of copper-brass seals realized by JRC according to DG ENER requirements. DG ENER processes about 20,000 metal seals per year. The verification of metal seals consists in visually checking the identity of a removed seal. The identity of a copper-brass seal is defined by a random stain pattern realized by the seal producer together with random scratches engraved when the seals are initialized ('seal production'). In order to verify that the seal returned from the field is the expected one its pattern is compared with an image taken during seal production. Formerly, seal initialization and verification were very heavy tasks as seal pictures were acquired with a camera one by one both in the initialization and verification stages. During the initialization the Nuclear Safeguards technicians had to place one by one new seals under a camera and acquire the related reference images. During the verification, the technician had to take used seals and place them one by one under a camera to take new pictures. The new images were presented to the technicians without any preprocessing and the technicians had to recognize the seal. The new station described in this paper has an automated image acquisition system allowing to easily process seals in batches of 100 seals. To simplify the verification, a software automatically centres and rotates the newly acquired seal image in order to perfectly overlap with the reference image acquired during the production phase. The new system significantly speeds up seal production and helps particularly with the demanding task of seal verification. As a large part of the seals is dealt with by a joint Euratom-IAEA team, the IAEA directly profits from this development. The new tool has been in routine use since mid 2013. (author)

ASTUS system for verifying the transport seal TITUS 1

International Nuclear Information System (INIS)

Barillaux; Monteil, D.; Destain, G.D.

1991-01-01

ASTUS, a system for acquisition and processing ultrasonic signatures of TITUS 1 seals has been developed. TITUS seals are used to verify the integrity of the fissile material's container sealing after transport. An autonomous portable reading case permit to take seals signatures at the starting point and to transmit these reference signatures to a central safeguards computer by phonic modem. Then, at the terminal point with a similar reading case, an authority takes again the signature of seals and immediately transmit these signatures to the central safeguards computer. The central computer processes the data in real time by autocorrelation and return its verdict to the terminal point

CBM sealing system and its relationship with CBM enrichment

Directory of Open Access Journals (Sweden)

Yonglin Ouyang

2017-01-01

Full Text Available It is of great significance to study the controlling effect of sealing systems on CBM enrichment in coalbed methane (CBM exploration and development. In this paper, the relationships between CBM enrichment and geological elements were analyzed. The geological elements include sealing layers (e.g. regional cap rock, regional floor, and immediate roof and floor, later structural adjustment and strata production status. It is shown that CBM tends to enrich in the areas where regional mudstone cap rocks and floors are distributed stably, structures are uplifted and inversed slightly after the hydrocarbon accumulation period and the strata is gentle in a balanced state. Then, the concept of sealing system was put forward based on the worldwide CBM exploration and development practices over the years. A sealing system refers to a geological unit composed of a lateral stable zone and cap rock which prevents gas from migrating upward and downward. In a sealing system, CBM can get enriched and coal-measure gas can also be accumulated. Finally, three gas reservoir types (i.e., sandwich-type CBM reservoir, associated CBM-sandstone gas reservoir and coal-derived sandstone gas reservoir were identified based on the configuration relationships between elements of the CBM (or coal-measure gas sealing system. It is recommended to change the exploration ideas from simple CBM exploration to 3D CBM and coal-measure gas exploration. In addition, an evaluation index system of CBM (or coal-measure gas geological selection was established. It is pointed out that good application effects may be realized if the stereoscopic CBM and coal-measure gas exploration is applied in the Junggar Basin and the eastern margin of the Ordos Basin.

Static and transient characteristics of the shaft seal system for helium gas circulator (Part 1)

International Nuclear Information System (INIS)

Morohoshi, S.; Saki, K.; Nemoto, M.; Taniguchi, S.; Sugimoto, A.; Kojima, M.

1982-01-01

A development program of the shaft seal system for the helium circulator supported by water lubricated bearings is presented. A seal system simulating tester and a computer program which can simulate the transient characteristics of a buffer gas seal system were newly introduced, and an investigation was performed experimentally and analytically of the characteristics of water and gas seals and of the buffer gas seal system including the control system. Main results are as follows: (1) Water seals were especially investigated in detail, and it was found that turbulence in water flow through seal clearance and deformation of seal components affected the leakage characteristics of water seals. They should be considered not only to make safety design but also to get optimum design of the seal system. (2) The calculation method for transient response of the buffer gas seal system including the control system was developed. This digital simulating method can well simulate transients encountered in the tester, and it would make a powerful tool for developing a safe seal system under steady state operation conditions and at depressurization accidents in a reactor

VACOSS - variable coding seal system for nuclear material control

International Nuclear Information System (INIS)

Kennepohl, K.; Stein, G.

1977-12-01

VACOSS - Variable Coding Seal System - is intended to seal: rooms and containers with nuclear material, nuclear instrumentation and equipment of the operator, instrumentation and equipment at the supervisory authority. It is easy to handle, reusable, transportable and consists of three components: 1. Seal. The light guide in fibre optics with infrared light emitter and receiver serves as lead. The statistical treatment of coded data given in the seal via adapter box guarantees an extremely high degree of access reliability. It is possible to store the data of two undue seal openings together with data concerning time and duration of the opening. 2. The adapter box can be used for input or input and output of data indicating the seal integrity. 3. The simulation programme is located in the computing center of the supervisory authority and permits to determine date and time of opening by decoding the seal memory data. (orig./WB) [de

The CANDU irradiated fuel safeguards sealing system at the threshold of implementation

International Nuclear Information System (INIS)

Stirling, A.J.; Kupca, S.; Martin, R.E.; West, R.J.; Aikens, A.E.; Cox, C.A.; White, B.F.; Smith, M.T.; Payne, W.E.

1985-07-01

The development of a safeguards containment and surveillance system for the irradiated fuel discharged from CANDU nuclear generating stations has inspired the development of three different sealing technologies. Each seal type utilizes a random seal identity of different design. The AECL Random Coil (ARC) Seal combines the identity and integrity elements in the ultrasonic signature of a wire coil. Two variants of an optical seal have been developed which features identity elements of crystalline zirconium and aluminum. The sealed cap-seal uses a conventional IAEA 'Type X Seal' (wire seal). The essential features and relative merits of each seal design are described

Study on tamper-indicating technology in electronic seals system

International Nuclear Information System (INIS)

Xu Xiong; Han Feng; Zuo Guangxia; Zhao Xin; Zhang Quanhu; Di Yuming

2009-01-01

To strengthen our national arms control verification technical storage and deepen electronic seals' research, this paper mainly introduces seals' characteristics, functions and work principle, studies on tamper-indicating technology which is a key technology in electronic seals, designs some hardware circuit such as optical transceiver, temperature detection circuit, move detection circuit, re-prized circuit and so on, also designs a software program which is used for recording the destroying or tampering events' information. Experimental results show that electronic seals system can record the destroying or tampering events' information accurately and quickly, and give corresponding tamper-indication. (authors)

An innovative sealed shoe to off-load and heal diabetic forefoot ulcers - a feasibility study.

Science.gov (United States)

Jarl, Gustav; Tranberg, Roy

2017-01-01

Background : Non-removable knee-high devices are the gold standard to treat diabetic foot ulcers located on the plantar forefoot, but they immobilize the ankle, which restricts daily life activities and has negative effects on joint functioning. Objective : To investigate the feasibility of sealing a therapeutic shoe to off-load and heal diabetic forefoot ulcers. Design : A case series of seven men with type 2 diabetes and a metatarsal head ulcer were prescribed therapeutic shoes and custom-made insoles. The shoe was sealed with a plastic band. Off-loading was assessed with the F-scan pressure measurement system. Adherence to wearing the shoe was assessed with a temperature sensor and by documenting the status of the seal. Results : The off-loading was effective and all ulcers healed. Median time to healing was 56 days (range 8-160). Complications were secondary ulcer ( n  = 1) and plantar hematoma ( n  = 1). Five of seven participants did not disturb the seal. Conclusions : Sealing a therapeutic shoe is a feasible way to off-load and heal forefoot ulcers. A controlled trial is needed to compare the effectiveness and safety of a sealed shoe to other non-removable devices.

Performance of the coned-face end seal with regard to energy conservation

Science.gov (United States)

Sehnal, J.; Sedy, J.; Zobens, A.; Etsion, I.

1982-01-01

The effects of face coning on seal performance are evaluated with particular regard to the energy saving potential of convex conedface end seals as indicated by torque reduction. Experiments were conducted using a conventional carbon flat-face pusher-type seal, a coned-face pusher-type seal, coned-face bellows-type seal, and a modified coned-face pusher-type seal intended for dynamically unstable operation, with shaft rotation at up to 8000 rpm, pressures of up to 2758 kPa, and a petroleum-based turbine oil as lubricant. Torque at the seal interface is found to be reduced by 42% when the standard flat-face seal is replaced by a coned seal, although the leakage of the cone-face seal was 11 times greater. Reduction of seal balance from 76.1 to 51.3% resulted in an additional 44% reduction in torque, although at the expense of excessive leakage, but did not produce unstable operation. Face temperatures were reduced by 33-56 C and wear was also reduced greatly on the cone face seals. Seal performance is noted to be in agreement with analytical calculations.

Advanced ceramic material for high temperature turbine tip seals

Science.gov (United States)

Solomon, N. G.; Vogan, J. W.

1978-01-01

Ceramic material systems are being considered for potential use as turbine blade tip gas path seals at temperatures up to 1370 1/4 C. Silicon carbide and silicon nitride structures were selected for study since an initial analysis of the problem gave these materials the greatest potential for development into a successful materials system. Segments of silicon nitride and silicon carbide materials over a range of densities, processed by various methods, a honeycomb structure of silicon nitride and ceramic blade tip inserts fabricated from both materials by hot pressing were tested singly and in combination. The evaluations included wear under simulated engine blade tip rub conditions, thermal stability, impact resistance, machinability, hot gas erosion and feasibility of fabrication into engine components. The silicon nitride honeycomb and low-density silicon carbide using a selected grain size distribution gave the most promising results as rub-tolerant shroud liners. Ceramic blade tip inserts made from hot-pressed silicon nitride gave excellent test results. Their behavior closely simulated metal tips. Wear was similar to that of metals but reduced by a factor of six.

Low Leakage Turbine Shaft Seals for Advanced Combined Cycle Systems.

Science.gov (United States)

1984-11-01

Study of Shaft Face Seal With Self-Acting Lift Augmentation", N71- 11579, Nov. 1970 29p. Povinelli , V.P. and McKibbin, A. H., "Development of...34, N73-24086, May 1973, 28p. Povinelli , V. P. and McKibbin, A. H., "Development of Mainshaft Seals for Advanced Air Breathing Propulsion Systems... Povinelli , V. P., "Current Seal Designs and Future Requirements for Turbine Engine Seals and Bearings", Journal of Aircraft, Vol. 12, No. 4, April 1975

Experimental research on friction factor of end faces of contacting mechanical seals

Science.gov (United States)

Wei, Long; Gu, Bo-qin; Feng, Xiu; Sun, Jian-jun

2008-11-01

The friction of the seal faces is the most important phenomenon in working process of contacting mechanical seals. The friction factor f is a key parameter for expressing the friction regime of the seal faces, the frictional power, the wearing capacity, the friction heat productivity, the temperature distortion of the end face and the temperature of the end face. The relationship between the friction factor f and the friction regime of the end faces of contacting mechanical seals was discussed from a microscopic point of view. The friction factor is usually worked out by the friction torque which is measured in the test. In the computer aided testing device of the mechanical seal system, the experimental investigations on the basic performance of the B104a-70 contacting mechanical seal was carried out. The test results indicate that the bigger the spring pressure of B104a-70 contacting mechanical seal, the bigger the friction factor. When the spring pressure is less, the bigger the rotational speed, the bigger the friction factor. But when the spring pressure is equal to 0.0866 MPa, the friction factor is not almost influenced by the rotational speed. When the rotational speed and spring pressure are less, the medium pressure has a less influence on the friction factor. When the rotational speed or spring pressure is bigger, the bigger the medium pressure, the less the friction factor.

Fiber Optic Safeguards Sealing System

Science.gov (United States)

1978-01-01

8217 or trade names does not constitute an official indorsement or approval of the use thereof. Destroy this report when it is no longer needed. Do not...an intergrity check of a seal than to photograph the seal’s fingerprints and to match positive/negative overlays. The seal identification time and

An implantable centrifugal blood pump with a recirculating purge system (Cool-Seal system).

Science.gov (United States)

Yamazaki, K; Litwak, P; Tagusari, O; Mori, T; Kono, K; Kameneva, M; Watach, M; Gordon, L; Miyagishima, M; Tomioka, J; Umezu, M; Outa, E; Antaki, J F; Kormos, R L; Koyanagi, H; Griffith, B P

1998-06-01

A compact centrifugal blood pump has been developed as an implantable left ventricular assist system. The impeller diameter is 40 mm, and pump dimensions are 55 x 64 mm. This first prototype, fabricated from titanium alloy, resulted in a pump weight of 400 g including a brushless DC motor. The weight of a second prototype pump was reduced to 280 g. The entire blood contacting surface is coated with diamond like carbon (DLC) to improve blood compatibility. Flow rates of over 7 L/min against 100 mm Hg pressure at 2,500 rpm with 9 W total power consumption have been measured. A newly designed mechanical seal with a recirculating purge system (Cool-Seal) is used for the shaft seal. In this seal system, the seal temperature is kept under 40 degrees C to prevent heat denaturation of blood proteins. Purge fluid also cools the pump motor coil and journal bearing. Purge fluid is continuously purified and sterilized by an ultrafiltration unit which is incorporated in the paracorporeal drive console. In vitro experiments with bovine blood demonstrated an acceptably low hemolysis rate (normalized index of hemolysis = 0.005 +/- 0.002 g/100 L). In vivo experiments are currently ongoing using calves. Via left thoracotomy, left ventricular (LV) apex descending aorta bypass was performed utilizing an expanded polytetrafluoroethylene (ePTFE) vascular graft with the pump placed in the left thoracic cavity. In 2 in vivo experiments, the pump flow rate was maintained at 5-9 L/min, and pump power consumption remained stable at 9-10 W. All plasma free Hb levels were measured at less than 15 mg/dl. The seal system has demonstrated good seal capability with negligible purge fluid consumption (<0.5 ml/day). In both calves, the pumps demonstrated trouble free continuous function over 6 month (200 days and 222 days).

The electronic sealing system, VACOSS, as a control measure for international safeguards

International Nuclear Information System (INIS)

Kennepohl, K.; Maeckelburg, D.; Stein, G.

1979-01-01

The electronic sealing system VACOSS (Variable Coding Sealing System) was developed at KFA Juelich within the framework of an IAEA research contract. The seal is equipped with a light guide which acts as a lock. Statistical infra-red wavelength light pulses are transmitted via this light guide. The electronic components of the seal can store the opening and closing events of the light guide. In addition, the quasi-statistic treatment of code data fed into the seal by means of an adapter box guarantees an extremely high protection against unauthorized access. The portable seal is easy to handle, can be operated with a battery and can be re-used immediately after replacement of this battery. To make the seal operational code data are fed in, and the information stored in the seal can be read via the adapter box. Two versions of VACOSS were developed. VACOSS I permits the state of the seal in the facility to be checked on site only. VACOSS II can be monitored remotely by an operator passing on coded information. (author)

Seal design alternatives study

International Nuclear Information System (INIS)

Van Sambeek, L.L.; Luo, D.D.; Lin, M.S.; Ostrowski, W.; Oyenuga, D.

1993-06-01

This report presents the results from a study of various sealing alternatives for the WIPP sealing system. Overall, the sealing system has the purpose of reducing to the extent possible the potential for fluids (either gas or liquid) from entering or leaving the repository. The sealing system is divided into three subsystems: drift and panel seals within the repository horizon, shaft seals in each of the four shafts, and borehole seals. Alternatives to the baseline configuration for the WIPP seal system design included evaluating different geometries and schedules for seal component installations and the use of different materials for seal components. Order-of-magnitude costs for the various alternatives were prepared as part of the study. Firm recommendations are not presented, but the advantages and disadvantages of the alternatives are discussed. Technical information deficiencies are identified and studies are outlined which can provide required information

Operating reliability of the shaft seal system of ANDRITZ RCP

International Nuclear Information System (INIS)

Grancy, Werner; Zehentner, Martin

2002-01-01

The next generation of nuclear power stations will have to fulfil new expectations in terms of safety, operating behaviour and costs. This applies also and especially to reactor coolant pumps for the primary circuit of pressurized water reactor type nuclear power plants (RCP). For 4 decades, ANDRITZ AG has developed and built RCPs and has attached great importance to the design of the complete pump rotor and of its essential surrounding elements, such as e. g. the shaft seal. Many questions concerning design and configuration of the shaft seal system cannot be answered purely theoretically, or they can only be answered partly. Therefore, comprehensive development work and testing was necessary to increase the operating reliability of the seal. Apart from all relevant questions connected with design and functioning of the pump there is one question of top priority: the operating reliability of the shaft seal system. Therefore it is intended to describe the current status of design and development of ANDRITZ RCP for future Korean NPPs, to present the most important design features and to give an introduction concerning experiences for a 3-stage-hydrodynamic seal as well as for a 2-stage-hydrodynamic seal

VACOSS 3, a versatile and tamper-resistant electronic sealing system

International Nuclear Information System (INIS)

Arning, F.; Reuters, H.; Bueker, H.

1981-01-01

Seal systems for c/s instrumentation used at present need considerable technical and personal expenditure for installation and verification. This paper describes new electronic seal system VACOSS 3, developed by ProCom GmbH, Aachen, and the Nuclear Research Center Juelich within the frame work of an IAEA research contract. This system allows simple installation, verification, the possibility of remote verification and has high tamper resistance

Innovation to reality for improved pump seal performance

International Nuclear Information System (INIS)

Wong, W.; Eyvindson, A.; Rhodes, D.B.

2003-01-01

'Full-Text:' The nuclear industry requires reliable pump seals. Extended operating conditions for aging plants (i.e., low pressure starts, pressure and temperature transients) and increasing demands from new plants (larger sizes, higher speeds) are pushing the operating envelope for seals. This means that many seals that were previously considered adequate are now requiring increased attention and care. Operating utilities have taken different approaches to addressing their existing, or emerging, seal problems. Primary concerns include maintenance practices, seal design, and monitoring capabilities, as well as operating conditions, transients, pump and motor design. Success in this area requires ongoing dialogue among the station operators, pump manufacturers and seal designers. Regardless of the design, the basic requirement in CANDU is a reliable seal lifetime exceeding 5 years. This paper describes AECL's efforts to meet this requirement through an ongoing program of research and development in seal technology. Current work includes rigorous testing and evaluation of new seal materials and coatings to maximize seal stability and minimize friction and wear (i.e., pressure/temperature transients produce unpredictable shaft movement that can significantly alter face deflections affecting leak rates and seal stability, and sometimes cause the seal to hang-up and de-stage). Also required is a practical method for on-line monitoring of the condition of the seal, whether it is newly installed or after several years of reliable performance. This provides crucial information for inventory, maintenance and outage planning. While new concepts may look good on paper, it is only after they have been demonstrated under fully representative station operating conditions that they can truly be considered ready for field use. AECL CAN-seals lead the nuclear industry in reliability and seal life. They effectively save operators millions of dollars in outage time and person

Pressure Actuated Leaf Seals for Improved Turbine Shaft Sealing

Science.gov (United States)

Grondahl, Clayton

2006-01-01

This presentation introduces a shaft seal in which leaf seal elements are constructed from slotted shim material formed and layered into a frusto-conical assembly. Limited elastic deflection of seal leaves with increasing system pressure close large startup clearance to a small, non-contacting, steady state running clearance. At shutdown seal elements resiliently retract as differential seal pressure diminishes. Large seal clearance during startup and shutdown provides a mechanism for rub avoidance. Minimum operating clearance improves performance and non-contacting operation promises long seal life. Design features of this seal, sample calculations at differential pressures up to 2400 psid and benefit comparison with brush and labyrinth seals is documented in paper, AIAA 2005 3985, presented at the Advanced Seal Technology session of the Joint Propulsion Conference in Tucson this past July. In this presentation use of bimetallic leaf material will be discussed. Frictional heating of bimetallic leaf seals during a seal rub can relieve the rub condition to some extent with a change in seal shape. Improved leaf seal rub tolerance is expected with bimetallic material.

Predicting railway wheel wear under uncertainty of wear coefficient, using universal kriging

International Nuclear Information System (INIS)

Cremona, Marzia A.; Liu, Binbin; Hu, Yang; Bruni, Stefano; Lewis, Roger

2016-01-01

Railway wheel wear prediction is essential for reliability and optimal maintenance strategies of railway systems. Indeed, an accurate wear prediction can have both economic and safety implications. In this paper we propose a novel methodology, based on Archard's equation and a local contact model, to forecast the volume of material worn and the corresponding wheel remaining useful life (RUL). A universal kriging estimate of the wear coefficient is embedded in our method. Exploiting the dependence of wear coefficient measurements with similar contact pressure and sliding speed, we construct a continuous wear coefficient map that proves to be more informative than the ones currently available in the literature. Moreover, this approach leads to an uncertainty analysis on the wear coefficient. As a consequence, we are able to construct wear prediction intervals that provide reasonable guidelines in practice. - Highlights: • Wear prediction is of outmost importance for reliability of railway systems. • Wear coefficient is essential in prediction through Archard's equation. • A novel methodology is developed to predict wear and RUL. • Universal kriging is used for wear coefficient and uncertainty estimation. • A simulation study and a real case application are provided.

Analysis of experimental shaft seal data for high-performance turbomachines, as for Space Shuttle main engines

Science.gov (United States)

Hendricks, R. C.; Braun, M. J.; Mullen, R. L.; Burcham, R. E.; Diamond, W. A.

1985-01-01

High-pressure, high-temperature seal flow (leakage) data for nonrotating and rotating Raleigh-step and convergent-tapered-bore seals were characterized in terms of a normalized flow coefficient. The data for normalized Rayleigh-steip and nonrotating tapered-bore seals were in reasonable agreement with theory, but data for the rotating tapered-bore seals were not. The tapered-bore-seal operational clearances estimated from the flow data were significantly larger than calculated. Although clearances are influenced by wear from conical to cylindrical geometry and errors in clearance corrections, the problem was isolated to the shaft temperature - rotational speed clearance correction. The geometric changes support the use of some conical convergence in any seal. Under these conditions rotation reduced the normalized flow coefficiently by nearly 10 percent.

Analysis of experimental shaft seal data for high-performance turbomachines - As for Space Shuttle main engines

Science.gov (United States)

Hendricks, R. C.; Mullen, R. L.; Braun, M. J.; Burcham, R. E.; Diamond, W. A.

1987-01-01

High-pressure, high-temperature seal flow (leakage) data for nonrotating and rotating Raleigh-step and convergent-tapered-bore seals were characterized in terms of a normalized flow coefficient. The data for normalized Rayleigh-step and nonrotating tapered-bore seals were in reasonable agreement with theory, but data for the rotating tapered-bore seals were not. The tapered-bore-seal operational clearances estimated from the flow data were significantly larger than calculated. Although clearances are influenced by wear from conical to cylindrical geometry and errors in clearance corrections, the problem was isolated to the shaft temperature - rotational speed clearance correction. The geometric changes support the use of some conical convergence in any seal. Under these conditions rotation reduced the normalized flow coefficiently by nearly 10 percent.

Airborne Wear Particles Emissions fromCommercial Disc Brake Materials– Passenger Car Field Test

OpenAIRE

Wahlström, Jens; Olofsson, Ulf; Jansson, Anders; Olander, Lars

2008-01-01

Most modern passenger cars have disc brakes on the front wheels, which unlike drum brakes are not sealed off to the ambient air. During braking, there is wear to both the rotor and the pads. This wear process generates particles, which may become airborne. In field tests it is difficult to distinguish these particles from others in the surrounding environment. It may be preferable to use laboratory test stands where the cleanness of the surrounding air can be controlled. The validity of these...

Failure of Magnetic Fluid Seals Operating in Water: Preliminary Conclusions

Directory of Open Access Journals (Sweden)

Matuszewski Leszek

2017-06-01

Full Text Available The article analyses properties of magnetic fluid seals installed in rotary sealing nodes which operate in the utility water environment. Seals of this type have been examined as a possible solution to the problem with ship manoeuvring propulsion sealing. The present analysis bases on laboratory durability tests of magnetic fluid seals exposed to longterm utility water loads, at different water pressures and shaft revolutions. The basic seal durability criterion was the number of revolutions made by the sealing node shaft until the appearance of water tightness loss (leakage. It was found that the main factor leading to the wear of the seal is the relative speed of the magnetic fluid with respect to that of the utility water, and this process is heavily affected by the pressure acting on the seal. The reported test results are presented in the form of diagrams showing the seal durability (time until water tightness loss as a function of rotational speed. The curves shown in the diagrams are regular, with two different rotational speed ranges: the highspeed range, when the tightness loss is relatively fast, and the low-speed range, with a clear tendency to prolong the seal lifetime. These diagrams were given the name of durability curves of the MF seal operating in water. The results of the performed tests suggest formal similarity between the experimental data distribution concerning tightness loss processes occurring in magnetic fluid seals operating in water environment and metal fatigue processes. The article proposes a preliminary simplified durability model to describe the examined phenomenon.

Maintenance system for immersed seals, specifically for nuclear reactors

International Nuclear Information System (INIS)

Poindexter, A.M.; Ricks, H.E.

1977-01-01

The invention concerns the immersed seals of nuclear reactors and specifically a maintenance system for the immersed seals of the revolving closing plugs of liquid metal breeder nuclear reactors. A liquid sodium immersed joint may be located at a given place or be surrounded by heating elements so that the sodium stays liquid whilst the reactor is working. In other cases, the sodium in the immersed seal is allowed to solidify whilst the reactor is working, thereby increasing the efficiency of the seal. At all events, the sodium must be in a liquid state during reloading with fuel to enable the plug to turn. The invention consists in fitting an ultrasonic transducer to the closure head of the reactor vessel so that the vibration emitting surface directs these vibrations towards the immersed seals so as to detach the deposits of impurities on them and ensure the wetting of the metal surfaces of which they are formed. Additionally, an envelope that can be placed around the ultrasonic transducer in conjunction with a suction appliance provides a mechanism through which the impurities can be removed from the area of the immersed seal [fr

Study on microstructure and high temperature wear resistance of laser cladded nuclear valve clack

International Nuclear Information System (INIS)

Zhang Chunliang; Chen Zichen

2002-01-01

Laser cladding of Co-base alloy on the nuclear valve-sealing surface are performed with a 5 kW CO 2 transverse flowing laser. The microstructure and the high temperature impact-slide wear resistance of the laser cladded coating and the plasma cladded coating are studied. The results show that the microstructure, the dilution rate and the high temperature impact-slide wear resistance of the laser cladded coating have obvious advantages over the spurt cladding processing

An intelligent condition monitoring system for on-line classification of machine tool wear

Energy Technology Data Exchange (ETDEWEB)

Pan, Fu; Hope, A D; Javed, M [Systems Engineering Faculty, Southampton Institute (United Kingdom)

1998-12-31

The development of intelligent tool condition monitoring systems is a necessary requirement for successful automation of manufacturing processes. This presentation introduces a tool wear monitoring system for milling operations. The system utilizes power, force, acoustic emission and vibration sensors to monitor tool condition comprehensively. Features relevant to tool wear are drawn from time and frequency domain signals and a fuzzy pattern recognition technique is applied to combine the multisensor information and provide reliable classification results of tool wear states. (orig.) 10 refs.

An intelligent condition monitoring system for on-line classification of machine tool wear

Energy Technology Data Exchange (ETDEWEB)

Fu Pan; Hope, A.D.; Javed, M. [Systems Engineering Faculty, Southampton Institute (United Kingdom)

1997-12-31

The development of intelligent tool condition monitoring systems is a necessary requirement for successful automation of manufacturing processes. This presentation introduces a tool wear monitoring system for milling operations. The system utilizes power, force, acoustic emission and vibration sensors to monitor tool condition comprehensively. Features relevant to tool wear are drawn from time and frequency domain signals and a fuzzy pattern recognition technique is applied to combine the multisensor information and provide reliable classification results of tool wear states. (orig.) 10 refs.

Reliability modelling for wear out failure period of a single unit system

OpenAIRE

Arekar, Kirti; Ailawadi, Satish; Jain, Rinku

2012-01-01

The present paper deals with two time-shifted density models for wear out failure period of a single unit system. The study, considered the time-shifted Gamma and Normal distributions. Wear out failures occur as a result of deterioration processes or mechanical wear and its probability of occurrence increases with time. A failure rate as a function of time deceases in an early failure period and it increases in wear out period. Failure rates for time shifted distributions and expression for m...

Long-Term Durability Test for the Left Ventricular Assist System EVAHEART under the Physiologic Pulsatile Load.

Science.gov (United States)

Kitano, Tomoya; Iwasaki, Kiyotaka

The EVAHEART Left Ventricular Assist System (LVAS) was designed for the long-term support of a patient with severe heart failure. It has an original water lubrication system for seal and bearing and wear on these parts was considered one of its critical failure modes. A durability test focusing on wear was designed herein. We developed a mock loop, which generates a physiologic pulsatile flow and is sufficiently durable for a long-term test. The pulsatile load and the low fluid viscosity enable the creation of a severe condition for the mechanical seal. A total of 18 EVAHEART blood pumps completed 2 years of operation under the pulsatile condition without any failure. It indicated the EVAHEART blood pump had a greater than 90% reliability with a 88% confidence level. The test was continued with six blood pumps and achieved an average of 8.6 years, which was longer than the longest clinical use in Japan. The test result showed that no catastrophic, critical, marginal, or minor failures of the blood pump or their symptoms were observed. The seal performance was maintained after the test. Moreover, the surface roughness did not change, which showed any burn or abnormal wear occurred. The original water lubrication system equipped in EVAHEART LVAS prevent severe wear on the seal and the bearing, and it can be used in the bridge to transplant and destination therapy.

WIPP shaft seal system parameters recommended to support compliance calculations

International Nuclear Information System (INIS)

Hurtado, L.D.; Knowles, M.K.; Kelley, V.A.; Jones, T.L.; Ogintz, J.B.; Pfeifle, T.W.

1997-12-01

The US Department of Energy plans to dispose of transuranic waste at the Waste Isolation Pilot Plant (WIPP), which is sited in southeastern New Mexico. The WIPP disposal facility is located approximately 2,150 feet (650 m) below surface in the bedded halite of the Salado Formation. Prior to initiation of disposal activities, the Department of Energy must demonstrate that the WIPP will comply with all regulatory requirements. Applicable regulations require that contaminant releases from the WIPP remain below specified levels for a period of 10,000 years. To demonstrate that the WIPP will comply with these regulations, the Department of Energy has requested that Sandia National Laboratories develop and implement a comprehensive performance assessment of the WIPP repository for the regulatory period. This document presents the conceptual model of the shaft sealing system to be implemented in performance assessment calculations conducted in support of the Compliance Certification Application for the WIPP. The model was developed for use in repository-scale calculations and includes the seal system geometry and materials to be used in grid development as well as all parameters needed to describe the seal materials. These calculations predict the hydrologic behavior of the system. Hence conceptual model development is limited to those processes that could impact the fluid flow through the seal system

WIPP shaft seal system parameters recommended to support compliance calculations

Energy Technology Data Exchange (ETDEWEB)

Hurtado, L.D.; Knowles, M.K. [Sandia National Labs., Albuquerque, NM (United States); Kelley, V.A.; Jones, T.L.; Ogintz, J.B. [INTERA Inc., Austin, TX (United States); Pfeifle, T.W. [RE/SPEC, Inc., Rapid City, SD (United States)

1997-12-01

The US Department of Energy plans to dispose of transuranic waste at the Waste Isolation Pilot Plant (WIPP), which is sited in southeastern New Mexico. The WIPP disposal facility is located approximately 2,150 feet (650 m) below surface in the bedded halite of the Salado Formation. Prior to initiation of disposal activities, the Department of Energy must demonstrate that the WIPP will comply with all regulatory requirements. Applicable regulations require that contaminant releases from the WIPP remain below specified levels for a period of 10,000 years. To demonstrate that the WIPP will comply with these regulations, the Department of Energy has requested that Sandia National Laboratories develop and implement a comprehensive performance assessment of the WIPP repository for the regulatory period. This document presents the conceptual model of the shaft sealing system to be implemented in performance assessment calculations conducted in support of the Compliance Certification Application for the WIPP. The model was developed for use in repository-scale calculations and includes the seal system geometry and materials to be used in grid development as well as all parameters needed to describe the seal materials. These calculations predict the hydrologic behavior of the system. Hence conceptual model development is limited to those processes that could impact the fluid flow through the seal system.

Seal arrangement

International Nuclear Information System (INIS)

Dempsey, J.D.

1978-01-01

A hydraulically balanced face type shaft seal is provided in which the opening and closing seal face areas retain concentricity with each other in the event of lateral shaft displacement. The seal arrangement is for a vertical high pressure pump, indented for use in the cooling system of a nuclear reactor. (Auth.)

Improved sealing for in-core systems

International Nuclear Information System (INIS)

Dunford, S.

1989-01-01

The in-core instrumentation sealing nozzles designed by Framatome have three mechanical seals in series instead of the one traditional seal, and are pressurized by simply tightening up the nozzle covers. They have been installed from the start on all Framatome PWRs, as well as having been backfitted on Belgium and Yugoslavian units and chosen for the Chinese Qinshan plant. (author)

[Systemic spread of wear debris--an in-vivo study].

Science.gov (United States)

Burian, B; Wimmer, M A; Kunze, J; Sprecher, C M; Pennekamp, P H; von Engelhardt, L V; Diedrich, O; Kraft, C N

2006-01-01

The aim of this study was to elucidate whether there is a systemic spread of wear debris from peripherally applied stainless steel and titanium particles into the blood and subsequently to parenchymatous organs. Furthermore, we report on histological findings at the implantation site. In Syrian Gold hamsters we implanted 2 mm3 wear debris of stainless steel and titanium into the dorsal skin fold chamber. Over a period of 2 weeks we took blood samples and afterwards explanted the implant area, the heart, lung, liver and spleen. One half of the organs and the implant area were used for histological analysis. The other half of the organs and the blood samples were analysed by optical emission spectrometer with inductively coupled plasma and graphite furnace atomic absorption spectrophotometry for their contents of chromium, nickel and titanium. In the group with titanium particles, histological analysis of the implant site showed moderate phagocyted wear in granulocytes but no other pathological findings. Animals treated with stainless steel wear debris had a massive inflammatory reaction, in some cases leading to necrosis. The analysis of the blood and one half of the organs showed increased levels of chromium and, already 24 hours after implantation, raised values for nickel. The result of the hamsters treated with titanium showed significantly elevated levels of titanium ions in the organs, but not in the blood samples. Histology of the organs did not reveal pathological findings. In this study we could show a massive inflammatory reaction for stainless steel wear debris in contrast to titanium wear debris at the implantation site. The elevated blood levels of chromium and increased values of other metals in the organs suggest the haematogenic distribution of ions from the peripherally implanted wear debris.

Reliability Analysis of Sealing Structure of Electromechanical System Based on Kriging Model

Science.gov (United States)

Zhang, F.; Wang, Y. M.; Chen, R. W.; Deng, W. W.; Gao, Y.

2018-05-01

The sealing performance of aircraft electromechanical system has a great influence on flight safety, and the reliability of its typical seal structure is analyzed by researcher. In this paper, we regard reciprocating seal structure as a research object to study structural reliability. Having been based on the finite element numerical simulation method, the contact stress between the rubber sealing ring and the cylinder wall is calculated, and the relationship between the contact stress and the pressure of the hydraulic medium is built, and the friction force on different working conditions are compared. Through the co-simulation, the adaptive Kriging model obtained by EFF learning mechanism is used to describe the failure probability of the seal ring, so as to evaluate the reliability of the sealing structure. This article proposes a new idea of numerical evaluation for the reliability analysis of sealing structure, and also provides a theoretical basis for the optimal design of sealing structure.

Strength and wear resistance of a dental glass-ionomer cement with a novel nanofilled resin coating.

Science.gov (United States)

Lohbauer, Ulrich; Krämer, Norbert; Siedschlag, Gustavo; Schubert, Edward W; Lauerer, Brigitte; Müller, Frank A; Petschelt, Anselm; Ebert, Johannes

2011-04-01

To evaluate the influence of different resin coating protocols on the fracture strength and wear resistance of a commercial glass-ionomer cement (GIC). A new restorative concept [Equia (GC Europe)] has been introduced as a system application consisting of a condensable GIC (Fuji IX GP Extra) and a novel nanofilled resin coating material (G-Coat Plus). Four-point fracture strength (FS, 2 x 2 x 25 mm, 14-day storage, distilled water, 37 degrees C) were produced and measured from three experimental protocols: no coating GIC (Group 1), GIC coating before water contamination (Group 2), GIC coating after water contamination (Group 3). The strength data were analyzed using Weibull statistics. Three-body wear resistance (Group 1 vs. Group 2) was measured after each 10,000 wear cycles up to a total of 200,000 cycles using the ACTA method. GIC microstructure and interfaces between GIC and coating materials were investigated under SEM and CLSM. The highest FS of 26.1 MPa and the most homogenous behavior (m = 7.7) has been observed in Group 2. The coated and uncoated GIC showed similar wear resistance until 90,000 cycles. After 200,000 wear cycles, the coated version showed significantly higher wear rate (ANOVA, P< 0.05). The coating protocol has been shown to determine the GIC fracture strength. Coating after water contamination and air drying is leading to surface crack formation thus significantly reducing the FS. The resin coating showed a proper sealing of GIC surface porosities and cracks. In terms of wear, the coating did not improve the wear resistance of the underlying cement as similar or higher wear rates have been measured for Group 1 versus Group 2.

Computer system for identification of tool wear model in hot forging

Directory of Open Access Journals (Sweden)

Wilkus Marek

2016-01-01

Full Text Available The aim of the research was to create a methodology that will enable effective and reliable prediction of the tool wear. The idea of the hybrid model, which accounts for various mechanisms of tool material deterioration, is proposed in the paper. The mechanisms, which were considered, include abrasive wear, adhesive wear, thermal fatigue, mechanical fatigue, oxidation and plastic deformation. Individual models of various complexity were used for separate phenomena and strategy of combination of these models in one hybrid system was developed to account for the synergy of various mechanisms. The complex hybrid model was built on the basis of these individual models for various wear mechanisms. The individual models expanded from phenomenological ones for abrasive wear to multi-scale methods for modelling micro cracks initiation and propagation utilizing virtual representations of granular microstructures. The latter have been intensively developed recently and they form potentially a powerful tool that allows modelling of thermal and mechanical fatigue, accounting explicitly for the tool material microstructure.

A removable optical sealing system for application to international safeguards

International Nuclear Information System (INIS)

Martin, R.E.

1985-06-01

A removable, optically verifiable sealing system for CANDU spent fuel storage facilities has been developed. The seal is based on the use of unique crystal patterns formed in a pure metal identity/integrity element and has been designed for easy installation and removal using simple tooling. Since the seal is optically verified, a wide range of commercial instruments, including those in use by the IAEA, can be used to verify it. Futhermore, optical verification allows the level of scrutiny to be matched with the degree of confidence required to be confident that spent fuel has not been diverted

Tribology and Microstructure of PS212 with a Cr2O3 Seal Coat

Science.gov (United States)

Sliney, Harold E.; Benoy, Patricia A.; Korenyi-Both, Andras; Dellacorte, Christopher

1994-01-01

PS212 is a plasma sprayed metal bonding chrome carbide coating with solid lubricant additives which has lubricating properties at temperatures up to about 900 deg C. The coating is diamond ground to achieve an acceptable tribological surface. But, as with many plasma spray coatings, PS212 is not fully-dense. In this study, a chromium oxide base seal coating is used in an attempt to seal any porosity that is open to the surface of the PS212 coating, and to study the effect of the sealant on the tribological properties of PS212. The results indicate that the seal coating reduces friction and wear when it is applied and then diamond ground leaving a thin layer of seal coating which fills in the surface pits of the PS212 coating.

Aspects of crack-seal vein system evolution

OpenAIRE

Virgo, Simon Matthias

2015-01-01

This thesis focuses on the evolution of crack-seal vein systems under changing stress conditions. Thecharacteristics of these highly complex systems are explored in extensive field studies on the Jabal Akhdar(Oman Mountains), an exhumed high-pressure cell with a multiphase deformation history. Theimpact of mechanical heterogeneity on the fracture behavior and structure development in crack-sealvein systems is explored in several numerical studies facilitating the Discrete Element Method (DEM)...

Safeguards sealing systems for Zebra

International Nuclear Information System (INIS)

Ingram, G.; Jamieson, G.R.

1983-01-01

A relatively simple design has been produced for safeguards seals to be applied throughout the fuel containing areas at Zebra. It is based on the use of wire seals and regular Inspector surveillance. The application of the system would allow an Inspector to establish to a high degree of confidence that significant quantities of fuel had not been diverted during an intensive experimental programme. It would add about 5% to the time required for experiments, and careful planning would reduce this value. The inspection effort required to witness element movements during the experimental programme would average about 2 hours per day, with a further 2 hours spent each week on NDA of the fuel exposed. The Safeguards Inspector would require to spend about 25% of his time in the reactor area and would have ample time to deal with the relatively small number of fuel movements taking place in the storage area and with his duties elsewhere in the plant. During a core change, full-time inspection effort would be required for about 6 weeks each year. (author)

Ceramic Seal.

Energy Technology Data Exchange (ETDEWEB)

Smartt, Heidi A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Romero, Juan A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Custer, Joyce Olsen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hymel, Ross W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Krementz, Dan [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Gobin, Derek [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Harpring, Larry [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Martinez-Rodriguez, Michael [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Varble, Don [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); DiMaio, Jeff [Tetramer Technologies, Pendleton, SC (United States); Hudson, Stephen [Tetramer Technologies, Pendleton, SC (United States)

2016-11-01

Containment/Surveillance (C/S) measures are critical to any verification regime in order to maintain Continuity of Knowledge (CoK). The Ceramic Seal project is research into the next generation technologies to advance C/S, in particular improving security and efficiency. The Ceramic Seal is a small form factor loop seal with improved tamper-indication including a frangible seal body, tamper planes, external coatings, and electronic monitoring of the seal body integrity. It improves efficiency through a self-securing wire and in-situ verification with a handheld reader. Sandia National Laboratories (SNL) and Savannah River National Laboratory (SRNL), under sponsorship from the U.S. National Nuclear Security Administration (NNSA) Office of Defense Nuclear Nonproliferation Research and Development (DNN R&D), have previously designed and have now fabricated and tested Ceramic Seals. Tests have occurred at both SNL and SRNL, with different types of tests occurring at each facility. This interim report will describe the Ceramic Seal prototype, the design and development of a handheld standalone reader and an interface to a data acquisition system, fabrication of the seals, and results of initial testing.

Ceramic Seal

International Nuclear Information System (INIS)

Smartt, Heidi A.; Romero, Juan A.; Custer, Joyce Olsen; Hymel, Ross W.; Krementz, Dan; Gobin, Derek; Harpring, Larry; Martinez-Rodriguez, Michael; Varble, Don; DiMaio, Jeff; Hudson, Stephen

2016-01-01

Containment/Surveillance (C/S) measures are critical to any verification regime in order to maintain Continuity of Knowledge (CoK). The Ceramic Seal project is research into the next generation technologies to advance C/S, in particular improving security and efficiency. The Ceramic Seal is a small form factor loop seal with improved tamper-indication including a frangible seal body, tamper planes, external coatings, and electronic monitoring of the seal body integrity. It improves efficiency through a self-securing wire and in-situ verification with a handheld reader. Sandia National Laboratories (SNL) and Savannah River National Laboratory (SRNL), under sponsorship from the U.S. National Nuclear Security Administration (NNSA) Office of Defense Nuclear Nonproliferation Research and Development (DNN R&D), have previously designed and have now fabricated and tested Ceramic Seals. Tests have occurred at both SNL and SRNL, with different types of tests occurring at each facility. This interim report will describe the Ceramic Seal prototype, the design and development of a handheld standalone reader and an interface to a data acquisition system, fabrication of the seals, and results of initial testing.

The IRES electronic seal

International Nuclear Information System (INIS)

Autrusson, B.; Brochard, D.; Moreau, J.F.; Martin, J.C.

2001-01-01

In the framework of the French Support Program for the IAEA Safeguards, the 'Institut de Protection et de Surete Nucleaire' (IPSN), developed an electronic seal called Integrated and Reusable Electronic Seal (IRES) that enables independent verification by different inspectorates (IAEA, Euratom, and National Inspectorate). The seal can be remotely interrogated by radio frequency and integrated to other Containment/surveillance systems by serial line RS 485. Data are authenticated and the IRESMAG software manages in the seal reader all functionalities of the seal and records inspection data compatible with the IAEA's Seal Database. To perform this development, IPSN relies on industrial partners: SAPHYMO for the general architecture of the seal and the electronics, THALES for the authentication of data and the security of transmission. The main features of the IRES seal are the following: Interrogation by different inspectorate, allowing independent conclusions; Recording of events, including tampering, in a non-volatile memory; Authentication of data and enhanced security of the communication between the seal and the seal reader; Remote interrogation by an inspector or/and automatic for unattended systems or remote monitoring; Reusable after erasing the seal memory and replacement of the batteries

Intelligent wear mode identification system for marine diesel engines based on multi-level belief rule base methodology

Science.gov (United States)

Yan, Xinping; Xu, Xiaojian; Sheng, Chenxing; Yuan, Chengqing; Li, Zhixiong

2018-01-01

Wear faults are among the chief causes of main-engine damage, significantly influencing the secure and economical operation of ships. It is difficult for engineers to utilize multi-source information to identify wear modes, so an intelligent wear mode identification model needs to be developed to assist engineers in diagnosing wear faults in diesel engines. For this purpose, a multi-level belief rule base (BBRB) system is proposed in this paper. The BBRB system consists of two-level belief rule bases, and the 2D and 3D characteristics of wear particles are used as antecedent attributes on each level. Quantitative and qualitative wear information with uncertainties can be processed simultaneously by the BBRB system. In order to enhance the efficiency of the BBRB, the silhouette value is adopted to determine referential points and the fuzzy c-means clustering algorithm is used to transform input wear information into belief degrees. In addition, the initial parameters of the BBRB system are constructed on the basis of expert-domain knowledge and then optimized by the genetic algorithm to ensure the robustness of the system. To verify the validity of the BBRB system, experimental data acquired from real-world diesel engines are analyzed. Five-fold cross-validation is conducted on the experimental data and the BBRB is compared with the other four models in the cross-validation. In addition, a verification dataset containing different wear particles is used to highlight the effectiveness of the BBRB system in wear mode identification. The verification results demonstrate that the proposed BBRB is effective and efficient for wear mode identification with better performance and stability than competing systems.

Seals monitoring systems using wireless communications

International Nuclear Information System (INIS)

Hermand, Guillaume; Bertrand, Johan; Farhoud, Radwan; Suzuki, Kei; ETO, Jiro; Tanabe, Hiromi; Takamura, Hisashi; Suyama, Yasuhiro

2012-01-01

Document available in extended abstract form only. Wireless monitoring based on electromagnetic waves is a promising application for deep geological nuclear waste repositories. It should allow data transmission without installing wires across the various seals (disposal cell plugs, gallery plugs, shaft plugs). Developments of the wireless system (e.g. transmitter and receiver) are in progress in order to fit the repository requirements. A common research program has been elaborated by RWMC and Andra. The present work aims at developing the wireless monitoring technology to intermediate level waste (ILW) disposal facilities concept. In this concept, ILW packages will be emplaced in disposal cells with concrete liner. After the operational phase, the cells will be backfilled with sealing material. In practice, this work demonstrates the feasibility of adapting and optimizing the wireless transmission system for specific repository cases. After preliminary transmission studies, it was decided to make a representative test in situ of a wireless transmission through the clay from a sealed side to an accessible side of the repository. In order to reduce the attenuation of magnetic flux caused by steel components between the transmitter and the receiver, the receiving antenna is installed in a dedicated borehole (drilled from the accessible side). Two types of reception antennas have been designed. According to its coil orientation, type A antenna measures the electromagnetic wave perpendicular to the borehole axis. On the other hand, type B antenna with a coil set in-line with the tubular casing, measures the electromagnetic wave parallel to the borehole axis. The outside cylinder (pressure tight case) is made of PVC considering the attenuation of electromagnetic flux. According to the direction of electromagnetic flux and position of the boreholes in the final repository design, type A or type B will be chosen. For the 'representative' test, a borehole, TSF1002 has been

Failure analysis and seal life prediction for contacting mechanical seals

Science.gov (United States)

Sun, J. J.; He, X. Y.; Wei, L.; Feng, X.

2008-11-01

Fault tree analysis method was applied to quantitatively investigate the causes of the leakage failure of mechanical seals. It is pointed out that the change of the surface topography is the main reasons causing the leakage of mechanical seals under the condition of constant preloads. Based on the fractal geometry theory, the relationship between the surface topography and working time were investigated by experiments, and the effects of unit load acting on seal face on leakage path in a mechanical seal were analyzed. The model of predicting seal life of mechanical seals was established on the basis of the relationship between the surface topography and working time and allowable leakage. The seal life of 108 mechanical seal operating at the system of diesel fuel storage and transportation was predicted and the problem of the condition monitoring for the long-period operation of mechanical seal was discussed by this method. The research results indicate that the method of predicting seal life of mechanical seals is feasible, and also is foundation to make scheduled maintenance time and to achieve safe-reliability and low-cost operation for industrial devices.

Sealing Failure Analysis on V-Shaped Sealing Rings of an Inserted Sealing Tool Used for Multistage Fracturing Processes

Directory of Open Access Journals (Sweden)

Gang Hu

2018-06-01

Full Text Available The inserted sealing tool is a critical downhole implement that is used to balance the downhole pressure in multistage fracturing operations and prevent fracturing fluid from overflow and/or backward flow. The sealing ring of an inserted sealing tool plays an important role in downhole sealing since a sealing failure would ail the fracturing operation. In order to improve the sealing performance and reduce the potential fracturing failures, this research aims to investigate the influence of V-shaped sealing ring geometries on sealing performance. Constitutive experiments of rubber materials were carried out and the parameters of the constitutive relationship of rubber materials were obtained. A two-dimensional axisymmetric model considering the sealing ring has been established and influences are investigated with considerations of various system parameters and operating conditions. It is found that the stresses concentrated at the shoulder and inner vertex of the sealing ring have direct impact on the damage of the sealing rings under operational conditions. Moreover, the sealing interference, among several other factors, greatly affects the life of the sealing ring. A new design of the sealing ring is suggested with optimized geometric parameters. Its geometric parameters are the edge height of 5 mm, the vertex angle of 90°–100°, and the interference of 0.1 mm, which show a better performance and prolonged operation life of the sealing ring.

A durable, non power consumptive, simple seal for rotary blood pumps.

Science.gov (United States)

Mitamura, Y; Sekine, K; Asakawa, M; Yozu, R; Kawada, S; Okamoto, E

2001-01-01

One of the key technologic requirements for rotary blood pumps is the sealing of the motor shaft. A mechanical seal, a journal bearing, magnetic coupling, and magnetic suspension have been developed, but they have drawbacks such as wear, thrombus formation, and power consumption. A magnetic fluid seal was developed for an axial flow pump. A magnetic fluid seal is durable, simple, and non power consumptive. Long-term experiments and finite element modeling (FEM) analyses confirmed these advantages. The seal body was composed of a Ned-Fe magnet and two pole pieces; the seal was formed by injecting ferrofluid into the gap (50 microm) between the pole pieces and the motor shaft. To contain the ferrofluid in the seal and to minimize the possibility of ferrofluid making contact with blood, a shield with a small cavity was attached to the pole piece. While submerged in blood, the sealing pressure of the seal was measured and found to be 188 mm Hg with ferrofluid LS-40 (saturated magnetization, 24.3 kA/m) at a motor speed of 10,000 rpm and 225 mm Hg under static conditions. The magnetic fluid seals performed perfectly at a pressure of 100 mm Hg for 594 + days in a static condition, and 51, 39+, and 34+ days at a motor speed of 8,000 rpm. FEM analyses indicated a theoretical sealing pressure of 260 mm Hg. The state of the magnetic fluid in the seal in water was observed with a microscope. Neither splashing of magnetic fluid nor mixing of the magnetic fluid and water was observed. The specially designed magnetic fluid seal for keeping liquids out is useful for axial flow blood pumps. The magnetic fluid seal was incorporated into an intracardiac axial flow pump.

Dynamic performance of a C/C composite finger seal in a tilting mode

Directory of Open Access Journals (Sweden)

Hailin ZHAO

2017-08-01

Full Text Available The complex operating state of aeroengines has an impact on the performance of finger seals. However, little work has been focused on the issue and the dynamic performance of finger seals is also rarely studied. Therefore, a distributed mass equivalent model considering working conditions is proposed in this paper for solving the existing problems. The effects of the fiber bundle density and the preparation direction of the fiber bundle of a C/C composite on the dynamic performance of a finger seal are investigated in rotor tilt based on the proposed model. The difference between the C/C composite finger seal performances under the rotor precession and nutation tilt cases is also investigated. The results show that the fiber bundle density and the preparation direction of the fiber bundle have an influence on the dynamic performance of the finger seal as rotor tilt is considered, and the dynamic performance of the finger seal is different in the two kinds of tilting modes. In addition, a novel method for design of finger seals is presented based on the contact pressure between finger boots and the rotor. Finger seals with good leakage rates and low wear can be acquired in this method.

Static seals and their application in water-cooled nuclear reactor systems

International Nuclear Information System (INIS)

Anon.

1976-01-01

Information relative to six types of static seals commonly used in the primary cooling systems of nuclear reactors is compiled. This information includes a description of each type of seal, its material of construction, design features, operating experience, and advantages and disadvantages. The types covered include spiral-wound asbestos-filled gaskets, hollow metallic O-rings, Belleville spring type of gasketed joints, integrated elastomer and metal retainer gaskets, and solid metal gaskets with heavy cross sections. Omega, canopy, and lip seals are discussed briefly, and information on flange design for gasketing is also presented

Experience with an ultrasonic sealing system for nuclear safeguards in irradiated fuel bay demonstrations

International Nuclear Information System (INIS)

White, B.F.; Smith, M.T.

1985-07-01

The development of the irradiated fuel safeguards containment assembly for CANDU nuclear generating stations has stimulated the development of the AECL Random Coil Sealing System. The ARC seal combines the identity and integrity elements in an ultrasonically-determined signature. This is verified in situ, in real time with the seal reading system. The maturation of this technology has been facilitated with demonstration trials in the NRU and NPD irradiated fuel bays. The NPD demonstration includes operation of the systems tooling by Ontario Hydro staff. It provides the opportunity for IAEA inspectors from Toronto and Vienna to direct the operational procedures and to perform the data acquisition. The procedures and systems developed in these trials are reviewed. The estimation of the system performance characteristics from the observations is presented. A minimum frequency of reading for individual seals is recommended to be once per annum following initial deployment

TECHNOLOGY ROADMAPPING FOR IAEA SEALS.

Energy Technology Data Exchange (ETDEWEB)

HOFFHEINS,B.; ANNESE,C.; GOODMAN,M.; OCONNOR,W.; GUSHUE,S.; PEPPER,S.

2003-07-13

In the fall of 2002, the U.S. Support Program (USSP) initiated an effort to define a strategy or ''roadmap'' for future seals technologies and to develop a generalized process for planning safeguards equipment development, which includes seals and other safeguards equipment. The underlying objectives of the USSP include becoming more proactive than reactive in addressing safeguards equipment needs, helping the IAEA to maintain an inventory of cost-effective, reliable, and effective safeguards equipment, establishing a long-term planning horizon, and securing IAEA ownership in the process of effective requirements definition and timely transitioning of new or improved systems for IAEA use. At an initial workshop, seals, their functions, performance issues, and future embodiments were discussed in the following order: adhesive seals, metal seals, passive and active loop seals, ultrasonic seals, tamper indicating enclosures (including sample containers, equipment enclosures, and conduits). Suggested improvements to these technologies focused largely on a few themes: (1) The seals must be applied quickly, easily, and correctly; (2) Seals and their associated equipment should not unduly add bulk or weight to the inspectors load; (3) Rapid, in-situ verifiability of seals is desirable; and (4) Seal systems for high risk or high value applications should have two-way, remote communications. Based upon these observations and other insights, the participants constructed a skeletal approach for seals technology planning. The process begins with a top-level review of the fundamental safeguards requirements and extraction of required system features, which is followed by analysis of suitable technologies and identification of technology gaps, and finally by development of a planning schedule for system improvements and new technology integration. Development of a comprehensive procedure will require the partnership and participation of the IAEA. The

Analysis on Sealing Reliability of Bolted Joint Ball Head Component of Satellite Propulsion System

Science.gov (United States)

Guo, Tao; Fan, Yougao; Gao, Feng; Gu, Shixin; Wang, Wei

2018-01-01

Propulsion system is one of the important subsystems of satellite, and its performance directly affects the service life, attitude control and reliability of the satellite. The Paper analyzes the sealing principle of bolted joint ball head component of satellite propulsion system and discuss from the compatibility of hydrazine anhydrous and bolted joint ball head component, influence of ground environment on the sealing performance of bolted joint ball heads, and material failure caused by environment, showing that the sealing reliability of bolted joint ball head component is good and the influence of above three aspects on sealing of bolted joint ball head component can be ignored.

Bearing compartment seal systems for turbomachinery in direct-cycle HTGR power plants

International Nuclear Information System (INIS)

Adams, R.G.; Boenig, F.H.; Pfeifer, G.D.

1977-10-01

The direct-cycle High-Temperature Gas-Cooled Reactor (HTGR) employs a closed gas-turbine cycle with the primary reactor coolant (helium) as the working fluid. Design studies on this type of plant, carried out since 1971, have demonstrated, among other points, the advantages of the integrated arrangement, in which power from the cycle is transmitted to the electric generators by turbomachines completely enclosed in the reactor pressure vessel. A result of this arrangement is that the bearings are entirely enclosed within the primary coolant system of the reactor. An important aspect of the design of the turbomachinery is its prevention or minimization of the ingress of lubricants into the primary coolant system and its prevention of ingress of primary coolant into the bearing compartments. The design studies, which included thorough conceptual designs of the turbomachinery with emphasis on bearings and seals and their support systems showed that total exclusion of lubricant requires extremely complex seals and seal support systems. The variation of system low-end pressure with control actuation and the requirement that the bearing cavity pressure follow these variations were proved to further complicate the service system. The tolerance of even relatively minute amounts of entering lubricant during control transients will allow considerable simplification. This paper discusses the above-mentioned problems and their solutions in tracing the design evolution of a satisfactory bearing-compartment seals and service system. The resulting system appears to be feasible on the basis of experience with industrial gas turbines

State of art report for high temperature wear test of SMART MCP and CEDM bearing material

International Nuclear Information System (INIS)

Cho, Yong Hu; Lee, Jae Seon; Park, Jin Seok; Kim, Ji Ho; Kim, Jong In

2000-03-01

Wear resistance properties of machine elements has been more critical in view of its significant effect on life extension, economics and material saving because it has been recognized that nearly 80 percent of damages of mechanical elements in the friction pairs are due to the material loss by wear. And wear properties have direct influence on the life of a machine in a great extend under extremely severe operating condition. Therefore highly improved wear properties of machine elements operating in such circumstances is heavily required. The purpose of this report is to survey current technology for high temperature wear test in order to establish the test plan for the life evaluation of SMART MCP and CEDM bearing materials. Friction and wear test will be done under high pressure (170 MPa) and high temperature (350 degree C) with water as lubricant to simulate the operating condition of the nuclear power reactor. Because pump type for MCP is selected as the caned motor pump which needs no mechanical sealing, the rotating shaft on which bearing is fully submerged by main coolant with high temperature. So MCP bearing operates without additional lubricant. CEDM is adopted as the ball-screw type with fine controllability. So the driving part is designed as the immersed-in type by main coolant. Therefore the anti-wear and reliability of driving parts are much consequent to guarantee the lifetime and the safety of the whole system. Tribometer adapted to high temperature and pressure circumstance is needed to execute bearing material testing. Test parameters are material, sliding speed, sliding distance and applied load. In order to identify the wear mechanism, optical microscope and surface roughness testers are required. The result of this report will provide an elementary data to develop bearing materials and to estimate bearing lifetime for the bearings of MCP and CEDM in SMART. (author)

Design of fiber optic electronic seal system based on C8051 microcontroller

International Nuclear Information System (INIS)

Di Yuming; Chen Rongye; Zuo Guangxia; Song Cang

2012-01-01

This paper presents fiber optic electronic seal system, witch uses C8051 microcontroller as core, matching other circuits such as optical signal detection module, movement detection module, temperature detection module and power module, etc. The results show that the seal system can record the tampering events' information accurately and quickly no matter there is one tamper event or more, and the ability of anti-tamper is improved. (authors)

High level nuclear waste repository in salt: Sealing systems status and planning report: Draft report

International Nuclear Information System (INIS)

1985-09-01

This report documents the initial conceptual design studies for a repository sealing system for a high-level nuclear waste repository in salt. The first step in the initial design studies was to review the current design level, termed schematic designs. This review identified practicality of construction and development of a design methodology as two key issues for the conceptual design. These two issues were then investigated during the initial design studies for seal system materials, seal placement, backfill emplacement, and a testing and monitoring plan. The results of these studies have been used to develop a program plan for completion of the sealing system conceptual design. 60 refs., 26 figs., 18 tabs

High pressure shaft seal

International Nuclear Information System (INIS)

Martinson, A.R.; Rogers, V.D.

1980-01-01

In relation to reactor primary coolant pumps, mechanical seal assembly for a pump shaft is disclosed which features a rotating seal ring mounting system which utilizes a rigid support ring loaded through narrow annular projections in combination with centering non-sealing O-rings which effectively isolate the rotating seal ring from temperature and pressure transients while securely positioning the ring to adjacent parts. A stationary seal ring mounting configuration allows the stationary seal ring freedom of motion to follow shaft axial movement up to 3/4 of an inch and shaft tilt about the pump axis without any change in the hydraulic or pressure loading on the stationary seal ring or its carrier. (author)

Discussion on sealing performance required in disposal system. Hydraulic analysis of tunnel intersections

International Nuclear Information System (INIS)

Sugita, Yutaka; Takahashi, Yoshiaki; Uragami, Manabu; Kitayama, Kazumi; Fujita, Tomoo; Kawakami, Susumu; Yui, Mikazu; Umeki, Hiroyuki; Miyamoto, Yoichi

2005-09-01

The sealing performance of a repository must be considered in the safety assessment of the geological disposal system of the high-level radioactive waste. NUMO and JNC established 'Technical Commission on Sealing Technology of Repository' based on the cooperation agreement. The objectives of this commission are to present the concept on the sealing performance required in the disposal system and to develop the direction for future R and D programme for design requirements of closure components (backfilling material, clay plug, etc.) in the presented concept. In the first phase of this commission, the current status of domestic and international sealing technologies were reviewed; and repository components and repository environments were summarized subsequently, the hydraulic analysis of tunnel intersections, where a main tunnel and a disposal tunnel in a disposal panel meet, were performed, considering components in and around the engineered barrier system (EBS). Since all tunnels are connected in the underground facility, understanding the hydraulic behaviour of tunnel intersections is an important issue to estimate migration of radionuclides from the EBS and to evaluate the required sealing performance in the disposal system. In the analytical results, it was found that the direction of hydraulic gradient, hydraulic conductivities of concrete and backfilling materials and the position of clay plug had impact on flow condition around the EBS. (author)

Design of repository sealing systems - 1981

International Nuclear Information System (INIS)

Ellison, R.D.; Shukla, D.K.; Kelsall, P.C.; D'Appolonia Consulting Engineers, Albuquerque, NM)

1982-01-01

Isolating nuclear waste in geologic repositories will require the sealing of penetrations such as access shafts and tunnels, disposal rooms, and exploration boreholes. This paper discusses seal designs developed for a repository in bedded salt referenced to the stratigraphy of southeastern New Mexico. Designs are based on a multiple component concept whereby individual components are designed for a specific function and location. For a repository in salt the major function of the seals is to exclude groundwater inflow. Two main types of component are included for this purpose: (1) bulk-heads are dense concrete structures keyed into the walls of the penetration and are intended to reduce flow at the interface between the seal and the salt; (2) backfills are granular materials compacted in place in the penetration. In the repository the major backfill material is crushed salt, which is expected to consolidate and recrystallize as the rooms close in response to salt creep. Densely compacted clays will be used as backfill in the shafts closer to potential sources of water inflow. 22 references, 10 figures, 1 table

Surface sealing systems for dumps and old waste sites. Oberflaechenabdichtungssysteme fuer Deponien und Altlasten

Energy Technology Data Exchange (ETDEWEB)

Egloffstein, T [ed.; ICP Ingenieurgesellschaft Prof. Czurda und Partner mbH, Karlsruhe (Germany); Burkhardt, G [ed.; ICP Ingenieurgesellschaft Prof. Czurda und Partner mbH, Karlsruhe (Germany)

1994-01-01

The primary task of surface lining is to prevent rainwater from seeping into the wastes deposited below the surface. Its function is therefore to seal the surface. Above the sealing layer there is a drainage system; if large amount of gas are generated (domestic wastes) the gas is channeled through a gas drainage layer. The top layer of the system serves as recultivation horizon for plants. The functions of the liner are: - sealing against precipitating water; - channeling off gas or - seepage water; - plant site. (orig./EF)

The IRES electronic seal

International Nuclear Information System (INIS)

Gourlez, P.; Funk, P.; Brochard, D.; Moreau, J.F.; Martin, J.C.

2001-01-01

In the framework of the French Support Program for the IAEA Safeguards, the 'Institut de Protection et de Surete Nucleaire' (IPSN), developed an electronic seal called Integrated and Reusable Electronic Seal (IRES) that enables independent verification by different inspectorates (IAEA, Euratom, and National Inspectorate) Furthermore, a bilateral co-ordination between Euratom and French domestic safeguards takes place in some French facilities regarding a common approach concerning the seals especially in case of crisis situation. The seal can be remotely interrogated by radio frequency and integrated to other Containment/surveillance systems by serial line RS 485. Data are authenticated and the IRESMAG software manages in the seal reader all functionalities of the seal and records inspection data compatible with the IAEA's Seal Database

A model for the Space Shuttle Main Engine High Pressure Oxidizer Turbopump shaft seal system

Science.gov (United States)

Paxson, Daniel E.

1990-01-01

A model of the High Pressure Oxidizer Turbopump (HPOTP) shaft seal system on the Space Shuttle Main Engine (SSME) is described. The model predicts the fluid properties and flow rates throughout this system for a number of conditions simulating failed seals. The results agree well with qualitative expectations and redline values but cannot be verified with actual data due to the lack thereof. The results indicate that each failure mode results in a unique distribution of properties throughout the seal system and can therefore be individually identified given the proper instrumentation. Furthermore, the detection process can be built on the principle of qualitative reasoning without the use of exact fluid property values. A simplified implementation of the model which does not include the slinger/labyrinth seal combination has been developed and will be useful for inclusion in a real-time diagnostic system.

Fluid moderator control system fuel assembly seal connector

International Nuclear Information System (INIS)

Veronesi, L.; Tower, S.N.; Klassen, W.E.

1987-01-01

A nuclear reactor is described comprising fuel assemblies having one or more flow channels therethrough, a core support plate having one or more flow channels therethrough, and seal connectors for sealingly connecting the one or more flow channels in the core support plate with the one or more flow channels in the fuel assemblies. The seal connectors each comprises a first portion and second portion each comprising an elongated member having a flow channel therethrough and being in substantial axial alignment with each other and being separated by a space therebetween, means for sealingly connecting the first portion o one or the one or more flow channels in the fuel assemblies, means for sealingly connecting the second portion to the first portion and for allowing relative motion between the portions, means for limiting the relative motion of the first and second portion in directions toward and away from each other, means for reconnectingly connecting and resealingly sealing the second portion to one of the one or more flow channels in the core support plate. It comprises a slip fit connection whereby the remote end of the second portion fits within whereby the remote end of the second portion fits within an opening in the core support plate which is in flow communication with the one or more flow channels in the core support plate and further comprises a ball and cones seal in series with axially spaced ring seals

Tooth wear and wear investigations in dentistry.

Science.gov (United States)

Lee, A; He, L H; Lyons, K; Swain, M V

2012-03-01

Tooth wear has been recognised as a major problem in dentistry. Epidemiological studies have reported an increasing prevalence of tooth wear and general dental practitioners see a greater number of patients seeking treatment with worn dentition. Although the dental literature contains numerous publications related to management and rehabilitation of tooth wear of varying aetiologies, our understanding of the aetiology and pathogenesis of tooth wear is still limited. The wear behaviour of dental biomaterials has also been extensively researched to improve our understanding of the underlying mechanisms and for the development of restorative materials with good wear resistance. The complex nature of tooth wear indicates challenges for conducting in vitro and in vivo wear investigations and a clear correlation between in vitro and in vivo data has not been established. The objective was to critically review the peer reviewed English-language literature pertaining to prevalence and aetiology of tooth wear and wear investigations in dentistry identified through a Medline search engine combined with hand-searching of the relevant literature, covering the period between 1960 and 2011. © 2011 Blackwell Publishing Ltd.

Hydrodynamic perception in true seals (Phocidae) and eared seals (Otariidae).

Science.gov (United States)

Hanke, Wolf; Wieskotten, Sven; Marshall, Christopher; Dehnhardt, Guido

2013-06-01

Pinnipeds, that is true seals (Phocidae), eared seals (Otariidae), and walruses (Odobenidae), possess highly developed vibrissal systems for mechanoreception. They can use their vibrissae to detect and discriminate objects by direct touch. At least in Phocidae and Otariidae, the vibrissae can also be used to detect and analyse water movements. Here, we review what is known about this ability, known as hydrodynamic perception, in pinnipeds. Hydrodynamic perception in pinnipeds developed convergently to the hydrodynamic perception with the lateral line system in fish and the sensory hairs in crustaceans. So far two species of pinnipeds, the harbour seal (Phoca vitulina) representing the Phocidae and the California sea lion (Zalophus californianus) representing the Otariidae, have been studied for their ability to detect local water movements (dipole stimuli) and to follow hydrodynamic trails, that is the water movements left behind by objects that have passed by at an earlier point in time. Both species are highly sensitive to dipole stimuli and can follow hydrodynamic trails accurately. In the individuals tested, California sea lions were clearly more sensitive to dipole stimuli than harbour seals, and harbour seals showed a superior trail following ability as compared to California sea lions. Harbour seals have also been shown to derive additional information from hydrodynamic trails, such as motion direction, size and shape of the object that caused the trail (California sea lions have not yet been tested). The peculiar undulated shape of the harbour seals' vibrissae appears to play a crucial role in trail following, as it suppresses self-generated noise while the animal is swimming.

Sealing of leaks in the bioshield cooling system of three research reactors

International Nuclear Information System (INIS)

May, R.; Taylor, M.F.

1995-01-01

Water leaks have occurred in the bioshield cooling system of three research reactors. These leaks have been plugged with a sealant based on a blend of a water-based resin and a bentonite-type clay originally developed for sealing similar leaks on power reactors. The mechanism of sealing and development testing of the sealant are described. Application of the sealant to the three reactors sealed the leaks. However, unlike experience with leaks in steel and aluminium systems, some leaks reappeared after several months service - albeit at a leak rate only a very small fraction of the original leak rate. The recurrent defects were readily retreated with sealant and hence, in these instances, the treatment is an effective maintenance procedure for any ageing reactor rather than a permanent cure. (orig.)

Increasing nuclear safety and operational reliability by upgrading the charging pump mechanical sealing system

International Nuclear Information System (INIS)

Loenhout, Gerard van; Nilsson, Peter; Jehander, Magnus

2016-01-01

For the Ringhals-2 nuclear power plant, three installed centrifugal pumps were designated to have a combined High Head Safety Injection function, as well as a Chemical Volume Control System function. The pumps were originally installed with rubber bellow type mechanical seals, which over time had demonstrated an unreliable sealing performance by displaying high leakages. In 2002, the Ringhals Maintenance engineers initiated to identify a more reliable and robust shaft sealing solution. In 2007, the project was launched and the installation of the first, new mechanical sealing solution took place in the autumn of 2011. In October 2014, these mechanical seals were dismantled and inspected. The inspection confirmed the expected reliability of the new solution.

Increasing nuclear safety and operational reliability by upgrading the charging pump mechanical sealing system

Energy Technology Data Exchange (ETDEWEB)

Loenhout, Gerard van [Flowserve Corporation, Etten-Leur (Netherlands); Nilsson, Peter [Flowsys Technologies AB, Moelndal (Sweden); Jehander, Magnus [Ringhals AB, Vaeroebacka (Sweden)

2016-07-01

For the Ringhals-2 nuclear power plant, three installed centrifugal pumps were designated to have a combined High Head Safety Injection function, as well as a Chemical Volume Control System function. The pumps were originally installed with rubber bellow type mechanical seals, which over time had demonstrated an unreliable sealing performance by displaying high leakages. In 2002, the Ringhals Maintenance engineers initiated to identify a more reliable and robust shaft sealing solution. In 2007, the project was launched and the installation of the first, new mechanical sealing solution took place in the autumn of 2011. In October 2014, these mechanical seals were dismantled and inspected. The inspection confirmed the expected reliability of the new solution.

Increasing nuclear safety and operational reliability by upgrading the charging pump mechanical sealing system

Energy Technology Data Exchange (ETDEWEB)

Loenhout, Gerard van [Flowserve Corporation, Etten-Leur (Netherlands); Nilsson, Peter [Flowsys Technologies AB, Moelndal (Sweden); Jehander, Magnus [Ringhals AB, Vaeroebacka (Sweden)

2016-03-15

For the Ringhals-2 nuclear power plant, three installed centrifugal pumps were designated to have a combined High Head Safety Injection function, as well as a Chemical Volume Control System function. The pumps were originally installed with rubber bellow type mechanical seals, which over time had demonstrated an unreliable sealing performance by displaying high leakages. In 2002, the Ringhals Maintenance engineers initiated to identify a more reliable and robust shaft sealing solution. In 2007, the project was launched and the installation of the first, new mechanical sealing solution took place in the autumn of 2011. In October 2014, these mechanical seals were dismantled and inspected. The inspection confirmed the expected reliability of the new solution.

Numerical Investigation of the Effect of Radial Lip Seal Geometry on Sealing Performance

Science.gov (United States)

Tok, G.; Parlar, Z.; Temiz, V.

2018-01-01

Sealing elements are often needed in industry and especially in machine design. With the change and development of machine technology from day to day, sealing elements show continuous development and change in parallel with these developments. Many factors influence the performance of the sealing elements such as shaft surface roughness, radial force, lip geometry etc. In addition, the radial lip seals must have a certain pre-load and interference in order to provide a good sealing. This also affects the friction torque. Researchers are developing new seal designs to reduce friction losses in mechanical systems. In the presented study, the effect of the lip seal geometry on sealing performance will be examined numerically. The numerical model created for this purpose will be verified with experimental data firstly. In the numerical model, shaft and seal will be modeled as hyper-elastic in 2D and 3D. NBR (Nitrile Butadiene Rubber) as seal material will be analyzed for the rotating shaft state at constant speed by applying a uniform radial force.

Fluid-structure interaction analysis of annular seals and rotor systems in multi-stage pumps

International Nuclear Information System (INIS)

Jiang, Qinglei; Zhai, Lulu; Wang, Leqin; Wu, Dazhuan

2013-01-01

Annular seals play an important role in determining the vibrational behavior of rotors in multi-stage pumps. To determine the critical speeds and unbalanced responses of rotor systems which consider annular seals, a fluid-structure interaction (FSI) method was developed, and the numerical method was verified by experiments conducted on a model rotor. In a typical FSI process, rotor systems are modeled based on a node-element method, and the motion equations are expressed in a type of matrix. To consider the influence of annular seals, dynamic coefficients of annular seals were introduced into the motion equations through matrix transformation. The test results of the model rotor showed good agreement with the calculated results. Based on the FSI method proposed here, the governing equations of annular seals were solved in two different ways. The results showed that the Childs method is more accurate in predicting a rotor's critical speed. The critical speeds of the model rotor were calculated at different clearance sizes and length/diameter ratios. Tilting coefficients of long seals were added to the dynamic coefficients to consider the influence of tilting. The critical speeds reached their maximum value when the L/D ratio was around 1.25, and tilting enhanced the rotor's stability when long annular seals were located in either end of the shaft.

System for the sealing of containers and pipelines, especially in nuclear power plants

International Nuclear Information System (INIS)

Gross, R.

1976-01-01

In order to seal containers and pipelines especially in nuclear power plants, it is suggested to incorporate hollow bodies of an elastic material in the pipeline connections which can be blown up by pressure-gas and which are placed for sealing on the inner walls of the pipe. During a longer shutdown, system parts can thus be protected from corrosion. Various forms of such cavities are shown in design examples. The sealed sections can be filled with inert gas (nitrogen). (RW/LH) [de

System for the sealing of containers and pipelines, especially in nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Gross, R

1976-01-22

In order to seal containers and pipelines especially in nuclear power plants, it is suggested to incorporate hollow bodies of an elastic material in the pipeline connections which can be blown up by pressure-gas and which are placed for sealing on the inner walls of the pipe. During a longer shutdown, system parts can thus be protected from corrosion. Various forms of such cavities are shown in design examples. The sealed sections can be filled with inert gas (nitrogen).

Reduced friction in engine sealing system for truck engines; Reibungsreduzierende Motorabdichtung bei Nutzfahrzeugmotoren

Energy Technology Data Exchange (ETDEWEB)

Reichert, Joachim [Kaco GmbH und Co. KG, Heilbronn (Germany). RADIA-Dichtsysteme; Schaefer, Peter [Kaco GmbH und Co. KG, Heilbronn (Germany). Nutzfahrzeuganwendungen

2010-04-15

The mechanical efficiency of the drive unit components, e.g. the prevention of friction loss, becomes more the focus point of many new developments in engines and drive trains. Radia rotary shaft seal rings as commonly used in utility vehicles cause an accordingly high friction, particularly when in big dimensions. Kaco has engineered a tailor made design of state of the art friction reducing sealing system generation called Fred. In the acronym ''F'' stands for friction and ''red'' stands for reduced. Kaco has defined three focus points of the performance profile from the already established Fred sealing system generation for further engineering when applied in utility vehicles. (orig.)

Guidelines to achieve seals with minimal leak rates for HWR-NPR coolant system components

International Nuclear Information System (INIS)

Finn, P.A.

1991-03-01

Seal design practices that are acceptable in pressurized-water and boiling-water reactors in the United States are not usable for the Heavy Water Reactor-New Production Reactor (HWR-NPR) because of the stringent requirement on tritium control for the atmosphere within its containment building. To maintain an atmosphere in which workers do not need protective equipment, the components of the coolant system must have a cumulative leak rate less than 0.00026 L/s. Existing technology for seal systems was reviewed with regard to flange, elastomer, valve, and pump design. A technology data base for the designers of the HWR-NPR coolant system was derived from operating experience and seal development work on reactors in the United States, Canada, and Europe. This data base was then used to generate guidelines for the design of seals and/or joints for the HWR-NPR coolant system. Also discussed are needed additional research and development, as well as the necessary component qualification tests for an effective quality control program. 141 refs., 21 figs., 14 tabs

Guidelines to achieve seals with minimal leak rates for HWR-NPR coolant system components

Energy Technology Data Exchange (ETDEWEB)

Finn, P.A.

1991-03-01

Seal design practices that are acceptable in pressurized-water and boiling-water reactors in the United States are not usable for the Heavy Water Reactor-New Production Reactor (HWR-NPR) because of the stringent requirement on tritium control for the atmosphere within its containment building. To maintain an atmosphere in which workers do not need protective equipment, the components of the coolant system must have a cumulative leak rate less than 0.00026 L/s. Existing technology for seal systems was reviewed with regard to flange, elastomer, valve, and pump design. A technology data base for the designers of the HWR-NPR coolant system was derived from operating experience and seal development work on reactors in the United States, Canada, and Europe. This data base was then used to generate guidelines for the design of seals and/or joints for the HWR-NPR coolant system. Also discussed are needed additional research and development, as well as the necessary component qualification tests for an effective quality control program. 141 refs., 21 figs., 14 tabs.

Wear if a NBR seal for a oil jack pump; Desgaste de um retentor de NBR utilizado em uma unidade de bombeio de petroleo

Energy Technology Data Exchange (ETDEWEB)

Lima, Washington B. de; Barros, Levi B.; Machado, Jonata F.; Silva, Jailson H. Costa da [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)], e-mail: uoxito@hotmail.com, e-mail: levibarreto@hotmail.com.br, e-mail: jonataferreira@hotmail.com, e-mail: jailson.costa@pop.com.br; Medeiros, Joao Telesforo N. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Grupo de Estudos de Tribologia], e-mail: medeirosj2@asme.org

2007-07-01

The NBR seals are used in tribological systems because they are resistance to solvent, oil and fuel. This elastomer is used in the jack pump (oil pump unit-PETROBRAS), it is located in the stuffing box. It converts the rotational movement of an electric motor to a vertical reciprocating movement to drive the pump shaft, generating a tribological contact between the polished rod and the seal, avoiding oil leakage. In this work, was developed an experimental test rig to simulate the sealing conditions of the tribological pair polished rod-seal package for a oil pumping unit in a 1:1 scale. In the experimental part of this work were used several techniques as thermal history, Scanning Electron Microscope (SEM), hardness and mass losses analysis. The friction influence on the temperature was one of the most important effect caused by the contact. The SEM analyses and the hardness losses had evidenced the damage on the surface submitted to the contact. (author)

Radioactive tracer system to indicate drill bit wear or failure

International Nuclear Information System (INIS)

Fries, B.A.

1975-01-01

A radioactive tracer system for indicating drill bit wear or failure utilizing radioactive krypton 85 in clathrate form, in the form of water-soluble kryptonates, or dissolved grease, is described. Preferably the radioactive krypton is placed so that when drill bit wear or failure occurs, the radioactive krypton 85 is relased and effectively becomes diffused in the circulating drilling fluid. At the surface, the radioactive krypton 85 gas is separated from the circulating drilling fluid by gas-mud separating means and is transported as a gas to a counting chamber where an accurate radioactivity count of beta rays released from the krypton is obtained. (Patent Office Record)

Low pressure cooling seal system for a gas turbine engine

Science.gov (United States)

Marra, John J

2014-04-01

A low pressure cooling system for a turbine engine for directing cooling fluids at low pressure, such as at ambient pressure, through at least one cooling fluid supply channel and into a cooling fluid mixing chamber positioned immediately downstream from a row of turbine blades extending radially outward from a rotor assembly to prevent ingestion of hot gases into internal aspects of the rotor assembly. The low pressure cooling system may also include at least one bleed channel that may extend through the rotor assembly and exhaust cooling fluids into the cooling fluid mixing chamber to seal a gap between rotational turbine blades and a downstream, stationary turbine component. Use of ambient pressure cooling fluids by the low pressure cooling system results in tremendous efficiencies by eliminating the need for pressurized cooling fluids for sealing this gap.

Wear mechanisms and friction parameters for sliding wear of micron-scale polysilicon sidewalls

NARCIS (Netherlands)

Alsem, D. H.; van der Hulst, R.; Stach, E. A.; Dugger, M. T.; De Hosson, J. Th. M.; Ritchie, R. O.

As tribological properties are critical factors in the reliability of silicon-based microelectromechanical systems, it is important to understand what governs wear and friction. Average dynamic friction, wear volumes and morphology have been studied for polysilicon devices fabricated using the

Refurbishing the seals of the H2S compressors in the isotopic exchange installations at the Heavy Water Reprocessing Plant. Technical solutions for replacing liquid seals by dry seals

International Nuclear Information System (INIS)

Panait; Adrian; Serban, Viorel; Androne, Marian; Florea, Ioana; Ciocan, George; State, Elena

2004-01-01

An analysis of the present sealing system in the H 2 S compressors showed that the risk of accidental hydrogen sulfide escape into the atmosphere is high in case of a seal oil pressure loss. At the same time there exist drawbacks occurring even in normal regime of functioning among which one can mention: - relatively high losses of oil occur, part of the oil being carried away by the compressors and released into the isotopic exchange columns where the water counter current flow produces a foaming that reduces the column processing capacity; - part of the sealing oil leaks reaches the final product, the heavy water, where from it must be removed by chemical procedures; - the installations adjacent to the sealing system are relatively sophisticated and require relatively high expenses for exploitation and maintenance. The classical sealing systems using sealing rings, sleeves, labyrinths, etc, cannot be used since their safe working range is exceeded due to either driving shaft rotational speed, or to the increase of its diameter, or else to an increase of the speed of motion of moving parts relative to the fix parts. The sealing systems with magnetic liquids are rather sophisticated and expensive while in case of electric supply loss they are completely unsafe, because their sealing capacity vanishes. The materials used for sealing gaskets limit their application only to the cases when the relative motion of the moving pieces is low or vanishing what happens only at shut down or failure situations. To prevent these drawbacks of the present seal system in the H 2 S compressors of the isotopic exchange columns and having in view the limitations of the currently used sealing systems a new system of sealing was conceived and designed on the basis of the patent titled 'Sealing Installation and Procedure' recorded by OSIM under No. A/0315/10.04.2003. The new system can be built as a single or double stage each of them having in turn a dynamic and a static sub-stage. The

Ceramic/metal seals. [refractory materials for hermetic seals for lighium-metal sulfide batteries

Science.gov (United States)

Bredbenner, A. M.

1977-01-01

Design criteria are discussed for a hermetic seal capable of withstanding the 450 C operating temperature of a lithium-metal sulfide battery system. A mechanical seal consisting of two high strength alloy metal sleeves welded or brazed to a conductor assembly and pressed onto a ceramic is described. The conductor center passes through the ceramic but is not sealed to it. The seal is effected on the outside of the taper where the tubular part is pressed down over and makes contact.

Sealing of boreholes using natural, compatible materials: Granular salt

International Nuclear Information System (INIS)

Finley, R.E.; Zeuch, D.H.; Stormont, J.C.; Daemen, J.J.K.

1994-01-01

Granular salt can be used to construct high performance permanent seals in boreholes which penetrate rock salt formations. These seals are described as seal systems comprised of the host rock, the seal material, and the seal rock interface. The performance of these seal systems is defined by the complex interactions between these seal system components through time. The interactions are largely driven by the creep of the host formation applying boundary stress on the seal forcing host rock permeability with time. The immediate permeability of these seals is dependent on the emplaced density. Laboratory test results suggest that careful emplacement techniques could results in immediate seal system permeability on the order of 10 -16 m 2 to 10 -18 m 2 (10 -4 darcy to 10 -6 ). The visco-plastic behavior of the host rock coupled with the granular salts ability to ''heal'' or consolidate make granular salt an ideal sealing material for boreholes whose permanent sealing is required

Managing the aging of BWR control rod drive systems

International Nuclear Information System (INIS)

Greene, R.H.; Farmer, W.S.

1992-01-01

This Phase I Nuclear Plant Aging Research (NPAR) study examines the aging phenomena associated with BWR control and rod drive mechanisms (CRDMs) and assesses the merits of various methods of ''imaging'' this aging. Information for this study was acquired from (1) the results of a special CRDM aging questionnaire distributed to each US BWR utility, (2) a first-of-its-kind workshop held to discuss CRDM aging and maintenance concerns, (3) an analysis of the Nuclear Plant Reliability Data System (NPRDS) failure cases attributed to the control rod drive (CRD) system, and (4) personal information exchange with nuclear industry CRDM maintenance experts. The report documenting the findings of this research, NUREG-5699, will be published this year. Nearly 23% of the NPRDS CRD system component failure reports were attributed to the CRDM. The CRDM components most often requiring replacement due to aging are the Graphitar seals. The predominant causes of aging for these seals are mechanical wear and thermal embrittlement. More than 59% of the NPRDS CRD system failure reports were attributed to components that comprise the hydraulic control unit (HCU). The predominant HCU components experiencing the effects of service wear and aging are value seals, discs, seats, stems, packing, and diaphragms

Seals and sealing handbook

CERN Document Server

Flitney, Robert K

2007-01-01

Wherever machinery operates there will be seals of some kind ensuring that the machine remains lubricated, the fluid being pumped does not leak, or the gas does not enter the atmosphere. Seals are ubiquitous, in industry, the home, transport and many other places. This 5th edition of a long-established title covers all types of seal by application: static, rotary, reciprocating etc. The book bears little resemblance to its predecessors, and Robert Flitney has re-planned and re-written every aspect of the subject. No engineer, designer or manufacturer of seals can afford to be without this uniq

Full-scale demonstration. Fire testing of a system for penetration sealing based on foamed silicone elastomer: Studsvik 77-05-26

International Nuclear Information System (INIS)

Brown, A.

1978-06-01

Testing of a system for making fire retardant penetration seals based on foamed-in-place silicone elastomer is described. The report covers - Concept of fire retardant penetration seals and the Chemtrol system, Design FC 225 - Account of materials used to prepare seals and method of application - Test assembly and full-scale facility at Studsvik - Classification of seals used in demonstration - Diagrams of seals and photographs taken after demonstration

Full-scale demonstration. Fire testing of a system for penetration sealing based on foamed silicone elastomer: Studsvik 77-05-26

International Nuclear Information System (INIS)

Brown, A.

1978-06-01

Testing of a system for making fire retardant penetration seals based on foamed-in-place silicone elastomer is described. The report covers - Concept of fire retardant penetration seals and the Chemtrol system, Design FC 225 - Account of materials used to prepare seals and method of application - Test assembly and full-scale facility at Studsvik - Classification of seals used in demonstration - Diagrams of seals and photographs taken after demonstration (author)

An in vitro evaluation of the apical sealing ability of new polymeric endodontic filling systems.

Science.gov (United States)

Onay, Emel Olga; Ungor, Mete; Unver, Saadet; Ari, Hale; Belli, Sema

2009-08-01

The objective of this study was to compare the short-term sealing abilities of recently introduced polymeric endodontic filling systems. Root canals of 120 extracted and decoronated human single-rooted teeth were instrumented using crown-down technique with HERO Shaper rotary instruments. The roots were divided randomly into 8 groups (6 experimental and 2 control groups of 15 roots each) and filled with different combinations of core and sealer as follows: group 1, RealSeal/Resilon; group 2, RealSeal/Herofill; group 3, Hybrid Root Seal/Resilon; group 4, Hybrid Root Seal/Herofill; group 5, MM-Seal/Resilon; group 6, MM-Seal/Herofill; group 7, positive controls (Herofill only); group 8, negative controls. Apical leakage quantity was evaluated after 1 week by using a fluid filtration model. For each sample, measurements of fluid movement were recorded at 2-minute intervals for a total of 8 minutes, and then averaged. The data were calculated and analyzed using the Kolmogorov-Smirnov test, 1-way analysis of variance (ANOVA), and the Tukey test. Significance was set at P less than .05. Multiple paired comparisons (Tukey test) showed that, of all the groups, MM-Seal/Herofill combination exhibited the least microleakage, and RealSeal/Herofill combination ranked second in this regard. The mean leakage values for the RealSeal/Resilon and MM-Seal/Resilon combinations were both significantly higher than the means for the other 4 experimental groups (P < .01). Hybrid Root Seal combined with Resilon resulted in significantly less microleakage than Hybrid Root Seal combined with Herofill (P = .001). The results suggest that the sealing properties of epoxy-resin-based sealer (MM-Seal) combined with gutta-percha (Herofill) are superior to those of methacrylate-based sealers (Hybrid Root Seal and Realseal) combined with Resilon.

Radionuclide measuring systems and improved methods of evaluation for the measurement of wear in stationary and mobile systems

International Nuclear Information System (INIS)

Lausch, W.

1976-01-01

A newly developped flow through measuring unit makes it possible to perform continuous wear measurements on stationary and mobile systems. It was specifically designed for measurements on engine components of passenger cars. For tests of long duration an oil sampling technique was developed. Fully automated measurements are achieved with a sampling device suitable for both stationary and mobile systems. For systems with oil consumption a mathematical model provides for the necessary connection of the loss of wear particles through oil consumption. In certain cases an empirical graphical method can achieve nearly the same results. (orig.) [de

Study of ITER equatorial port plug handling system and vacuum sealing interface

Energy Technology Data Exchange (ETDEWEB)

Martins, Jean-Pierre [Association Euratom CEA, CEA/DSM/IRFM, Cadarache, F-13108 Saint-Paul-lez-Durance (France)], E-mail: jean-pierre.martins@cea.fr; Doceul, Louis; Marol, Sebastien; Delchie, Elise [Association Euratom CEA, CEA/DSM/IRFM, Cadarache, F-13108 Saint-Paul-lez-Durance (France); Cordier, Jean-Jacques; Levesy, Bruno; Tesini, Alessandro [ITER International Organization, F-13108 Saint-Paul-lez-Durance cedex (France); Ciattaglia, Emanuela [EFDA CSU - Garching, Boltzmannstr. 2, D-85748 Garching (Germany); Tivey, Richard [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Gillier, Rene; Abbes, Christophe [GARLOCK - Sealing Technologies - 90, rue de la roche du Geai, F-42029 St-Etienne cedex 1 (France)

2009-06-15

In the field of the ITER port plug engineering and integration task, CEA has contributed to define proposals concerning the port plugs vacuum sealing interface with the vessel flange and the equatorial plug handling. The 2001 baseline vacuum flange sealing consisted of TIG welding of a 316L strip plate on to U shapes. This arrangement presented some issues like welding access, implementation of tools, lip consumption, complex local leak test, continuous leak checking. Therefore, an alternate sealing solution based on the use of metallic gaskets is proposed. The different technical aspects are discussed to explain how this design can simplify the maintenance and deal with safety and vacuum requirements. The design of the mechanical attachment and vacuum sealing of the plug has constantly evolved, but the associated remote handling equipment was not systematically reviewed. An update of the cask and maintenance procedure was studied in order to design it in accordance with the last generic plug flange design. This includes a concept of a gripping system that uses the plug flange bolting area and, to help the remote handling process, a cantilever assisting system is suggested to increase the reliability of the transfer operation between vacuum vessel and cask.

Micro-Lid For Sealing Sample Reservoirs of micro-Extraction Systems

Data.gov (United States)

National Aeronautics and Space Administration — We propose to develop a proof-of-concept micro-Lid (µLid) to tightly seal a micro-sampler or micro-extraction system. Fabrication of µLid would be conducted in the...

The development of auto-sealing system for field joints of polyethylene coated pipelines

Energy Technology Data Exchange (ETDEWEB)

Okano, Yoshihiro [NKK Corp., Tsu, Mie (Japan); Shoji, Norio [NKK Corp., Yokohama (Japan); Namioka, Toshiyuki [Nippon Kokan Koji Corp., Osaka (Japan); Komura, Minoru [Nitto Denko Corp., Fukaya, Saitama (Japan)

1997-08-01

The paper describes the development of a system to create high quality, automatic sealing of field joints of polyethylene coated pipelines. The system uses a combination of electrically heated shrink sleeves and a low pressure chamber. The self-heating shrink sleeves include electric wires and heat themselves when connected to electricity. A method was developed to eliminate air trapped between the sleeve and steel pipe by shrinking the sleeves under low pressure. The low pressure condition was automatically and easily attained by using a vacuum chamber. The authors verified that the system produces high quality sealing of field joints.

Contact lens wear by Royal Air Force aircrew in World War II.

Science.gov (United States)

Pearson, Richard M

2014-04-01

To provide an overview of the use of contact lenses by RAF aircrew in World War II by identifying some of the fitters and wearers and appraising the clinical results that they achieved. A wide-ranging literature search was undertaken that encompassed peer-reviewed journals, non-refereed publications, books, official publications, newspapers and archived documents. Thirty-one aircrew are known to have worn sealed scleral lenses in order to meet the required visual standards. Of these, only two were considered to be completely unsuccessful, one of whom was unilaterally aphakic. One additional case of undisclosed contact lens wear was found and the identity of this officer was established. Brief biographies of a few pilots establish the context of their contact lens wear. Overall, the results of scleral lens wear were variable reflecting those achieved by civilian patients of the period. While three men complained of discomfort due to heat and glare, one pilot experienced no photophobia when flying above white clouds in brilliant sunshine and another found no difficulty caused by altitude or tropical climate. Wearing time ranged from about 2h to 16, or more, hours. In about a third of the cases, wearing time was limited due to the onset of a form of contact lens induced-epithelial oedema known as Sattler's veil and effective solutions to this problem were not implemented until after the war. Copyright © 2013 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Multi-Canister overpack sealing configuration

International Nuclear Information System (INIS)

SMITH, K.E.

1998-01-01

The Spent Nuclear Fuel (SNF) position regarding the Multi-Canister Overpack (MCO) sealing configuration is to initially rely on an American Society of Mechanical Engineers (ASME) Section III Subsection NB code compliant mechanical closure/sealing system to quickly and safely establish and maintain full confinement of radioactive materials prior to and during MCO fuel drying activities. Previous studies have shown the mechanical seal to be the preferred closure method, based on dose, cost, and schedule considerations. The cost and schedule impacts of redesigning the mechanical closure to a welded shield plug do not support changing the closure system. The SNF Project has determined that the combined mechanical/welded closure system meets or exceeds the regulatory requirements to provide redundant seals while accommodating key safety and schedule limitations that are unique to K Basins fuel removal effort

Development of simplified rotating plug seal structure

International Nuclear Information System (INIS)

Ueta, M.; Ichimiya, M.; Kanaoka, T.; Sekiya, H.; Ueda, S.; Ishibashi, S.

1991-01-01

We studied a compact and simplified rotating plug seal structure and conducted experiments for key elements of the concept such us the mechanical seal structure and sodium deposit prevention system. Good characteristics were confirmed for the mechanical seal structure, which utilizes an elastomer seal and thin lathe bearing. Applicability of the density barrier concept was also confirmed as the sodium deposit prevention system. This concept can be applied to actual plants. (author)

The PTFE-nanocomposites mechanical properties for transport systems dynamic sealing devices elements

Science.gov (United States)

Mashkov, Y. K.; Egorova, V. A.; Chemisenko, O. V.; Maliy, O. V.

2017-06-01

The mechanical properties study results of polymer nanocomposites based on polytetrafluoroethylene with modifiers in the form of micro- and nanoscale cryptocrystalline graphite and silicon dioxide powders are determined. The nanocomposites mechanical properties determined values provide high sealing degree of transport systems dynamic sealing devices elements. When the temperature changes from cryogenic to high positive then the elastic modulus, tensile strength decrease significantly and nonlinearly, the latter limits the composite usage in heavily loaded tribosystems operating at elevated temperatures.

A WEAR MODEL FOR DIESEL ENGINE EXHAUST VALVES

Energy Technology Data Exchange (ETDEWEB)

Blau, Peter Julian [ORNL

2009-11-01

The work summarized here comprises the concluding effort of a multi-year project, funded by the U.S. Department of Energy, Office of Vehicle Technologies. It supports the development of a better understanding of advanced diesel engine designs in which enhanced power density, energy efficiency, and emissions control place increasing demands upon the durability of engine materials. Many kinds of metallic alloys are used in engines depending on the operating stresses, temperatures, and chemical environments. Exhaust valves, for example, are subjected to high temperatures and repetitive surface contacts that place demands on durability and frictional characteristics of the materials. Valves must continue to seal the combustion chamber properly for thousands of hours of cyclic engine operation and under varying operating conditions. It was the focus of this effort to understand the wear processes in the valve-seat area and to develop a model for the surface deformation and wear of that important interface. An annotated bibliography is provided to illustrate efforts to understand valve wear and to investigate the factors of engine operation that affect its severity and physical manifestation. The project for which this modeling effort was the final task, involved construction of a high-temperature repetitive impact test system as well as basic tribology studies of the combined processes of mechanical wear plus oxidation at elevated temperatures. Several publications resulted from this work, and are cited in this report. The materials selected for the experimental work were high-performance alloys based on nickel and cobalt. In some cases, engine-tested exhaust valves were made available for wear analysis and to ensure that the modes of surface damage produced in experiments were simulative of service. New, production-grade exhaust valves were also used to prepare test specimens for experimental work along with the other alloy samples. Wear analysis of valves and seats

Performance of a tagged neutron inspection system (TNIS) based on portable sealed generators

International Nuclear Information System (INIS)

Nebbia, G.; Pesente, S.; Lunardon, M.; Viesti, G.; LeTourneur, P.; Heuveline, F.; Mangeard, M.; Tcheng, C.

2004-01-01

A portable sealed neutron generator has been modified to produce 14MeV tagged neutron beams with an embedded YAP:Ce scintillation detector. The system has been tested by detecting the coincident gamma-rays produced in the irradiation of a graphite sample by means of a standard NaI(Tl) scintillator. Time resolution of about δt=4-5ns (FWHM) has been measured. The sealed neutron tube has been operated up to 10 7 neutron/s. Possible applications in non-destructive assays and future developments of the Tagged Neutron Inspection System concept are discussed

Performance assessment of sealing systems. Conceptual and integrated modelling of plugs and seals

Energy Technology Data Exchange (ETDEWEB)

Ruebel, Andre; Buhmann, Dieter; Kindlein, Jonathan; Lauke, Thomas

2016-08-15

The long-time isolation of radionuclides from the biosphere is the goal of the storage of radioactive waste in deep geological repositories. For repositories in rock salt, this goal is achieved on the one hand by the impermeable undisturbed part of the salt host rock formation and on the other hand by crushed salt, which is used to backfill the mine openings in the emplacement areas and galleries created during the construction of the repository. The crushed salt backfill is compacted over time and achieves a sufficiently high hydraulic resistance to avoid inflow of brines into the emplacement areas of the repository in the long-term. Plugs and seals must additionally provide their sealing function during the early post closure phase, until the compaction of the backfill is adequate and the permeability of the backfill is sufficiently low. To assess the future development of the waste repository, an adequate knowledge of the material behaviour is necessary and related mathematical models must be developed to be able to perform predictions on the long-term safety of the repository. An integrated performance assessment model was formulated that describes the long-term behaviour of a sealing built from salt concrete. The average permeability of the sealing changes with time after its emplacement from various processes of which two were regarded in a constitutive model: first, the healing of the EDZ in the host rock around the sealing, and second, the corrosion of the salt concrete material resulting from brine attack. Empirical parameter model functions were defined for both processes to reflect the actual behaviour. The mathematical model was implemented in the integrated performance assessment model LOPOS which is used by GRS as near-field model for repositories in salt. Deterministic and probabilistic calculations were performed with realistic parameters showing how the permeability of the sealing decreases during the first 2 000 years due to the healing of the EDZ

Performance assessment of sealing systems. Conceptual and integrated modelling of plugs and seals

International Nuclear Information System (INIS)

Ruebel, Andre; Buhmann, Dieter; Kindlein, Jonathan; Lauke, Thomas

2016-08-01

The long-time isolation of radionuclides from the biosphere is the goal of the storage of radioactive waste in deep geological repositories. For repositories in rock salt, this goal is achieved on the one hand by the impermeable undisturbed part of the salt host rock formation and on the other hand by crushed salt, which is used to backfill the mine openings in the emplacement areas and galleries created during the construction of the repository. The crushed salt backfill is compacted over time and achieves a sufficiently high hydraulic resistance to avoid inflow of brines into the emplacement areas of the repository in the long-term. Plugs and seals must additionally provide their sealing function during the early post closure phase, until the compaction of the backfill is adequate and the permeability of the backfill is sufficiently low. To assess the future development of the waste repository, an adequate knowledge of the material behaviour is necessary and related mathematical models must be developed to be able to perform predictions on the long-term safety of the repository. An integrated performance assessment model was formulated that describes the long-term behaviour of a sealing built from salt concrete. The average permeability of the sealing changes with time after its emplacement from various processes of which two were regarded in a constitutive model: first, the healing of the EDZ in the host rock around the sealing, and second, the corrosion of the salt concrete material resulting from brine attack. Empirical parameter model functions were defined for both processes to reflect the actual behaviour. The mathematical model was implemented in the integrated performance assessment model LOPOS which is used by GRS as near-field model for repositories in salt. Deterministic and probabilistic calculations were performed with realistic parameters showing how the permeability of the sealing decreases during the first 2 000 years due to the healing of the EDZ

Innovative measuring system for wear-out indication of high power IGBT modules

DEFF Research Database (Denmark)

Nielsen, Rasmus Ørndrup; Due, Jens; Munk-Nielsen, Stig

2011-01-01

Power converter failures are a major issue in modern Wind turbines. One of the key elements of power converters for high power application is the IGBT modules. A test bench capable of performing an accelerated wear-out test through power cycling of IGBT modules has been made. In the test bench...... it is possible to stress the IGBT module in a real life working point, controlling the voltage, current and phase of the device under test. An analysis of failure mechanisms has been carried out, indicating that VCE can be used as an sign of wear out of the IGBT module. Therefore an innovative measuring system...... for VCE monitoring with an accuracy as low as a few mV has been implemented. The measurements on the IGBT in the test bench show that it is possible to monitor VCE and use this as an indicator of wear-out....

Metal and elastomer seal tests for accelerator applications

International Nuclear Information System (INIS)

Welch, K.M.; McIntyre, G.T.; Tuozzolo, J.E.; Skelton, R.; Pate, D.J.; Gill, S.M.

1989-01-01

The vacuum system of the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory has more than a thousand metal vacuum seals. Also, numerous elastomer seals are used throughout the AGS to seal large beam component chambers. An accelerator upgrade program is being implemented to reduce the AGS operating pressure by x100 and improve the reliability of the vacuum system. This paper describes work in progress on metal and elastomer vacuum seals to help meet those two objectives. Tests are reported on the sealing properties of a variety of metal seals used on different sealing surfaces. Results are also given on reversible sorption properties of certain elastomers. 16 refs., 6 figs., 4 tabs

Development and testing of improved polyimide actuator rod seals at higher temperatures for use in advanced aircraft hydraulic systems

Science.gov (United States)

Robinson, E. D.; Waterman, A. W.; Nelson, W. G.

1972-01-01

Polyimide second stage rod seals were evaluated to determine their suitability for application in advanced aircraft systems. The configurations of the seals are described. The conditions of the life cycle tests are provided. It was determined that external rod seal leakage was within prescribed limits and that the seals showed no signs of structural degradation.

Radiation tagging measures wear at speed

International Nuclear Information System (INIS)

Barrett, Jon.

1994-01-01

A new non-invasive technique for performing accelerated wear and corrosion analysis is particularly relevant to power transmission systems. Wear tests that would normally take days or weeks to complete can now be performed in hours. A tiny patch of the wearing component is made mildly radioactive and the drop in activity as material is worn away is monitored. Known as Thin Layer Activation (TLA), the technology was originally developed and pioneered in-house by the Atomic Energy Authority. Since then, the dominant partner has been the automotive sector where TLA has been used extensively for engine wear and lubrication performance analysis. However, TLA could be used in any wear or corrosion environment. Applications include wear analysis of machine tool cutting surfaces, pump impellers and brake linings to the corrosion monitoring of process plant and pipelines. (author)

Repair of a Kaplan blade sealing surface without dismantling the turbine; Instandsetzung einer Kaplanschaufel-Dichtflaeche ohne Turbinendemontage

Energy Technology Data Exchange (ETDEWEB)

Drygas, A.; Bauer, K. [E.ON Wasserkraft GmbH, Landshut (Germany)

2008-07-01

In spite of aiming at minimum maintenance costs, runners of Kaplan turbines need to be kept in good repair. Besides preserving their main function as an energy converter, ecological reasons have to be considered as well. The latter aspect accounts for fully functional, safe seals of the pivot-mounted Kaplan runner blades. Advanced wear of the sealing surfaces may require mechanical processing, which formerly called for a costly dismantling of the runner. A newly developed and patented processing device now allows for machining the worn out sealing surfaces without dismantling the runner, thus reducing costs considerably. The device was first successfully applied to a Kaplan turbine runner with a diameter of 5.35 m. The device, so far designed for grinding, will be enhanced for lathing, in order to obtain a process even more efficient when combining lathing and grinding. (orig.)

Cover-gas seals: 11-LMFBR seal-test program

International Nuclear Information System (INIS)

Steele, O.P. III; Horton, P.H.

1977-01-01

The objective of the Cover Gas Seal Material Development Program is to perform the engineering development required to provide reliable seals for LMFBR application. Specific objectives are to verify the performance of commercial solid cross-section and inflatable seals under reactor environments including radiation, to develop advanced materials and configurations capable of achieving significant improvement in radioactive gas containment and seal temperature capabilities, and to optimize seal geometry for maximum reliability and minimal gas permeation

Closure and Sealing Design Calculation

International Nuclear Information System (INIS)

T. Lahnalampi; J. Case

2005-01-01

The purpose of the ''Closure and Sealing Design Calculation'' is to illustrate closure and sealing methods for sealing shafts, ramps, and identify boreholes that require sealing in order to limit the potential of water infiltration. In addition, this calculation will provide a description of the magma that can reduce the consequences of an igneous event intersecting the repository. This calculation will also include a listing of the project requirements related to closure and sealing. The scope of this calculation is to: summarize applicable project requirements and codes relating to backfilling nonemplacement openings, removal of uncommitted materials from the subsurface, installation of drip shields, and erecting monuments; compile an inventory of boreholes that are found in the area of the subsurface repository; describe the magma bulkhead feature and location; and include figures for the proposed shaft and ramp seals. The objective of this calculation is to: categorize the boreholes for sealing by depth and proximity to the subsurface repository; develop drawing figures which show the location and geometry for the magma bulkhead; include the shaft seal figures and a proposed construction sequence; and include the ramp seal figure and a proposed construction sequence. The intent of this closure and sealing calculation is to support the License Application by providing a description of the closure and sealing methods for the Safety Analysis Report. The closure and sealing calculation will also provide input for Post Closure Activities by describing the location of the magma bulkhead. This calculation is limited to describing the final configuration of the sealing and backfill systems for the underground area. The methods and procedures used to place the backfill and remove uncommitted materials (such as concrete) from the repository and detailed design of the magma bulkhead will be the subject of separate analyses or calculations. Post-closure monitoring will not

Effect of different dental ceramic systems on the wear of human enamel: An in vitro study.

Science.gov (United States)

Zandparsa, Roya; El Huni, Rabie M; Hirayama, Hiroshi; Johnson, Marc I

2016-02-01

The wear of tooth structure opposing different advanced dental ceramic systems requires investigation. The purpose of this in vitro study was to compare the wear of advanced ceramic systems against human enamel antagonists. Four ceramic systems (IPS e.max Press, IPS e.max CAD, Noritake Super Porcelain EX-3, and LAVA Plus Zirconia) and 1 control group containing human enamel specimens were used in this study (n = 12). All specimens were fabricated as disks 11 mm in diameter and 3 mm thick. The mesiopalatal cusps of the maxillary third molars were prepared to serve as the enamel styluses. All specimens were embedded individually in 25 mm(3) autopolymerizing acrylic resin blocks. Wear was measured with a cyclic loading machine and a newly designed wear simulator. All enamel styluses (cusps) were scanned using the Activity 880 digital scanner (SmartOptics). Data from the base line and follow-up scans were collected and compared with Qualify 2012 3-dimensional (3D) and 2D digital inspection software (Geomagic), which aligned the models and detected the geometric changes and the wear caused by the antagonist specimen. One-way ANOVA was used to analyze the collected data. After 125,000 bidirectional loading cycles, the mean loss of opposing enamel volume for the enamel disks in the control group was 37.08 μm(3), the lowest mean value for IPS e.max Press system was 39.75 μm(3); 40.58 μm(3) for IPS e.max CAD; 45.08 μm(3) for Noritake Super Porcelain EX-3 system; and 48.66 μm(3) for the Lava Plus Zirconia system. No statically significant differences were found among the groups in opposing enamel volume loss (P=.225) or opposing enamel height loss (P=.149). In terms of opposing enamel height loss, Lava Plus Zirconia system showed the lowest mean value of 27.5 μm. The mean value for the IPS e.max CAD system was 27.91 μm; 29.08 μm for the control enamel; 33.25 μm for the IPS e.max Press system; and 34.75 μm for the Noritake Super Porcelain EX-3 system. Within the

Sealing device

Science.gov (United States)

Garcia-Crespo, Andres Jose

2013-12-10

A sealing device for sealing a gap between a dovetail of a bucket assembly and a rotor wheel is disclosed. The sealing device includes a cover plate configured to cover the gap and a retention member protruding from the cover plate and configured to engage the dovetail. The sealing device provides a seal against the gap when the bucket assemply is subjected to a centrifugal force.

3D finite element modeling of sliding wear

Science.gov (United States)

Buentello Hernandez, Rodolfo G.

Wear is defined as "the removal of material volume through some mechanical process between two surfaces". There are many mechanical situations that can induce wear and each can involve many wear mechanisms. This research focuses on the mechanical wear due to dry sliding between two surfaces. Currently there is a need to identify and compare materials that would endure sliding wear under severe conditions such as high velocities. The high costs associated with the field experimentation of systems subject to high-speed sliding, has prevented the collection of the necessary data required to fully characterize this phenomena. Simulating wear through Finite Elements (FE) would enable its prediction under different scenarios and would reduce experimentation costs. In the aerospace, automotive and weapon industries such a model can aid in material selection, design and/or testing of systems subjected to wear in bearings, gears, brakes, gun barrels, slippers, locomotive wheels, or even rocket test tracks. The 3D wear model presented in this dissertation allows one to reasonably predict high-speed sliding mechanical wear between two materials. The model predictions are reasonable, when compared against those measured on a sled slipper traveling over the Holloman High Speed Tests Track. This slipper traveled a distance of 5,816 meters in 8.14 seconds and reached a maximum velocity of 1,530 m/s.

Sealing of ceramic SOFC-components with glass seals; Fuegen von keramischen Komponenten der Hochtemperatur-Brennstoffzellen mittels Glas- und Glaskeramikloten

Energy Technology Data Exchange (ETDEWEB)

Schillig, Cora

2012-07-10

The solid oxide fuel cell (SOFC) converts chemical energy of a fuel directly into electrical energy. However, for the implementation of SOFC-technology in competition to conventional power plants costs have to be reduced. The use of an alternative tubular cell design without closed end would allow reducing costs during cell manufacturing. However, this change in design makes a gastight sealing inside the generator near the gas inlet necessary. Different ceramic materials with varying coefficients of thermal expansion have to be sealed gastight and electrical insulating at temperatures between 850 C and 1000 C to prevent the gases from mixing and an electrical shortcut between the cells. This work comprises analysis of commercially available glass and glass-ceramic systems manufactured by Schott Electronic Packaging, Areva T and D and Ferro Corporation. Additionally new developed sealing glass and glass-ceramic systems were investigated and all systems were characterized fundamentally for the use as sealing material in SOFC generators. Therefore different test assemblies and series were conducted. Essential characteristics of a suitable sealing system are a thermal expansion coefficient between 9,5 and 12 . 10{sup -6}K{sup -1}, a viscosity in the range between 10{sup 4} to 10{sup 6} dPa{sup *}s and a wetting angle smaller than 90 during the sealing process. Also unwanted chemical side reactions between the sealing partners must be prevented, because a change in the phase composition or the creation of new phases in the sealing material could endanger the stability of the seal. Heat cycles, particularly those during generator operation, cause deterioration of the sealing material and subsequent reduction in its ability to prevent mixing of the gases. Sealant leaks can drastically impact efficiency of the generator. In order to ensure optimum operation low leak rates around 2,3 . 10{sup -4} mbar l/sec/cm{sup 2} must be maintained. Especially glass and glass

Design and Analysis of a Shaft Seal System for the Waste Isolation Pilot Plant

International Nuclear Information System (INIS)

Hansen, F.D.; Knowles, M.K.

1999-01-01

This special issue of Reliability Engineering and System Safety presents a wide range of analyses pertaining to performance of the first EPA-certified nuclear waste repository, called the Waste Isolation Pilot Plant (WIPP). Licensing of the first such repository has involved unprecedented analysis accompanied by an equivalent peer review and public scmtiny. As a deep geologic repository, isolation of the repository from the biosphere requires implementation of unique seal systems. This paper describes the shall sealing system, which is designed to'mit fluid transport through the four existing shafts. The design approach applies redundancy to fictional elements and specifies multiple, common, low-permeability materials to ensure reliable performance. The system comprises 13 elements that completely fill the shafts with engineered materials possessing high density and low permeability. Laboratory and field measurements of component properties and performance provide the basis for the design and related evaluations. Hydrologic, mechanical, thermal, and physical features of the system are evaluated in a series of calculations. These sophisticated calculations indicate that the design effectively limits transport of fluids within the shafts, thereby limiting transport of waste material to regulatory boundaries. Additionally, the use or adaptation of existing technologies for seal construction combined with the use of available common materials assures that the design can be constructed

Actively controlled shaft seals for aerospace applications

Science.gov (United States)

Salant, Richard F.

1995-07-01

This study experimentally investigates an actively controlled mechanical seal for aerospace applications. The seal of interest is a gas seal, which is considerably more compact than previous actively controlled mechanical seals that were developed for industrial use. In a mechanical seal, the radial convergence of the seal interface has a primary effect on the film thickness. Active control of the film thickness is established by controlling the radial convergence of the seal interface with a piezoelectric actuator. An actively controlled mechanical seal was initially designed and evaluated using a mathematical model. Based on these results, a seal was fabricated and tested under laboratory conditions. The seal was tested with both helium and air, at rotational speeds up to 3770 rad/sec, and at sealed pressures as high as 1.48 x 10(exp 6) Pa. The seal was operated with both manual control and with a closed-loop control system that used either the leakage rate or face temperature as the feedback. The output of the controller was the voltage applied to the piezoelectric actuator. The seal operated successfully for both short term tests (less than one hour) and for longer term tests (four hours) with a closed-loop control system. The leakage rates were typically 5-15 slm (standard liters per minute), and the face temperatures were generally maintained below 100C. When leakage rate was used as the feedback signal, the setpoint leakage rate was typically maintained within 1 slm. However, larger deviations occurred during sudden changes in sealed pressure. When face temperature was used as the feedback signal, the setpoint face temperature was generally maintained within 3 C, with larger deviations occurring when the sealed pressure changes suddenly. the experimental results were compared to the predictions from the mathematical model. The model was successful in predicting the trends in leakage rate that occurred as the balance ratio and sealed pressure changed

Dental wear, wear rate, and dental disease in the African apes.

Science.gov (United States)

Elgart, Alison A

2010-06-01

The African apes possess thinner enamel than do other hominoids, and a certain amount of dentin exposure may be advantageous in the processing of tough diets eaten by Gorilla. Dental wear (attrition plus abrasion) that erodes the enamel exposes the underlying dentin and creates additional cutting edges at the dentin-enamel junction. Hypothetically, efficiency of food processing increases with junction formation until an optimal amount is reached, but excessive wear hinders efficient food processing and may lead to sickness, reduced fecundity, and death. Occlusal surfaces of molars and incisors in three populations each of Gorilla and Pan were videotaped and digitized. The quantity of incisal and molar occlusal dental wear and the lengths of dentin-enamel junctions were measured in 220 adult and 31 juvenile gorilla and chimpanzee skulls. Rates of dental wear were calculated in juveniles by scoring the degree of wear between adjacent molars M1 and M2. Differences were compared by principal (major) axis analysis. ANOVAs compared means of wear amounts. Pearson correlation coefficients were calculated to compare the relationship between molar wear and incidence of dental disease. Results indicate that quantities of wear are significantly greater in permanent incisors and molars and juvenile molars of gorillas compared to chimpanzees. The lengths of dentin-enamel junctions were predominantly suboptimal. Western lowland gorillas have the highest quantities of wear and the most molars with suboptimal wear. The highest rates of wear are seen in Pan paniscus and Pan t. troglodytes, and the lowest rates are found in P.t. schweinfurthii and G. g. graueri. Among gorillas, G. b. beringei have the highest rates but low amounts of wear. Coefficients between wear and dental disease were low, but significant when all teeth were combined. Gorilla teeth are durable, and wear does not lead to mechanical senescence in this sample.

Cover gas seals: FFTF-LMFBR seal test program

International Nuclear Information System (INIS)

Kurzeka, W.; Oliva, R.; Welch, T.S.; Shimazaki, T.

1974-01-01

The objectives of this program are to: (1) conduct static and dynamic tests to demonstrate or determine the mechanical performance of full-size (cross section) FFTF fuel transfer machine and reactor vessel head seals intended for use in a sodium vapor-inert gas environment, (2) demonstrate that these FFTF seals or new seal configurations provide acceptable fission product and cover gas retention capabilities at Clinch River Breeder Reactor Plant (CRBRP) operating environmental conditions other than radiation, and (3) develop improved seals and seal technology for the CRBRP to support the national objective to reduce all atmospheric contaminations to low levels

Modelling and measurement of wear particle flow in a dual oil filter system for condition monitoring

DEFF Research Database (Denmark)

Henneberg, Morten; Eriksen, René Lynge; Fich, Jens

2016-01-01

. The quantity of wear particles in gear oil is analysed with respect to system running conditions. It is shown that the model fits the data in terms of startup “particle burst” phenomenon, quasi-stationary conditions during operation, and clean-up filtration when placed out of operation. In order to establish...... boundary condition for particle burst phenomenon, the release of wear particles from a pleated mesh filter is measured in a test rig and included in the model. The findings show that a dual filter model, with startup phenomenon included, can describe trends in the wear particle flow observed in the gear...... particle generation is made possible by model parameter estimation and identification of an unintended lack of filter change. The model may also be used to optimise system and filtration performance, and to enable continuous condition monitoring....

A shaft seal system for the Waste Isolation Pilot Plant

International Nuclear Information System (INIS)

Hansen, F.D.; Ahrens, E.H.; Dennis, A.W.; Hurtado, L.D.; Knowles, M.K.; Tillerson, J.R.; Thompson, T.W.; Galbraith, D.

1996-01-01

As part of the demonstration of compliance with federal regulations, a shaft seal system has been designed for the Waste Isolation Pilot Plant. The system completely fills the 650 m shafts with components consisting of the common engineering materials, each of which possesses low permeability, longevity, and can be constructed using available technology. Design investigations couple rock mechanics and fluid flow analysis and tests of these materials within the natural geological setting, and demonstrate the effectiveness of the design

Energy and wear optimisation of train longitudinal dynamics and of traction and braking systems

Science.gov (United States)

Conti, R.; Galardi, E.; Meli, E.; Nocciolini, D.; Pugi, L.; Rindi, A.

2015-05-01

Traction and braking systems deeply affect longitudinal train dynamics, especially when an extensive blending phase among different pneumatic, electric and magnetic devices is required. The energy and wear optimisation of longitudinal vehicle dynamics has a crucial economic impact and involves several engineering problems such as wear of braking friction components, energy efficiency, thermal load on components, level of safety under degraded or adhesion conditions (often constrained by the current regulation in force on signalling or other safety-related subsystem). In fact, the application of energy storage systems can lead to an efficiency improvement of at least 10% while, as regards the wear reduction, the improvement due to distributed traction systems and to optimised traction devices can be quantified in about 50%. In this work, an innovative integrated procedure is proposed by the authors to optimise longitudinal train dynamics and traction and braking manoeuvres in terms of both energy and wear. The new approach has been applied to existing test cases and validated with experimental data provided by Breda and, for some components and their homologation process, the results of experimental activities derive from cooperation performed with relevant industrial partners such as Trenitalia and Italcertifer. In particular, simulation results are referred to the simulation tests performed on a high-speed train (Ansaldo Breda Emu V250) and on a tram (Ansaldo Breda Sirio Tram). The proposed approach is based on a modular simulation platform in which the sub-models corresponding to different subsystems can be easily customised, depending on the considered application, on the availability of technical data and on the homologation process of different components.

Repository Closure and Sealing Approach

International Nuclear Information System (INIS)

A.T. Watkins

2000-01-01

The scope of this analysis will be to develop the conceptual design of the closure seals and their locations in the Subsurface Facilities. The design will be based on the recently established program requirements for transitioning to the Site Recommendation (SR) design as outlined by ''Approach to Implementing the Site Recommendation Baseline'' (Stroupe 2000) and the ''Monitored Geologic Repository Project Description Document'' (CRWMS M andO 1999b). The objective of this analysis will be to assist in providing a description for the Subsurface Facilities System Description Document, Section 2 and finally to document any conclusions reached in order to contribute and provide support to the SR. This analysis is at a conceptual level and is considered adequate to support the SR design. The final closure barriers and seals for the ventilation shafts, and the north and south ramps will require these openings to be permanently sealed to limit excessive air and water inflows and prevent human intrusion. The major tasks identified with closure in this analysis are: (1) Developing the overall subsurface seal layout and identifying design and operational interfaces for the Subsurface Facilities. (2) Summarizing the general site conditions and general rock characteristic with respect to seal location and describing the seal selected. (3) Identify seal construction materials, methodology of construction and strategic locations including design of the seal and plugs. (4) Discussing methods to prevent human intrusion

3D cutting tool-wear monitoring in the process

Energy Technology Data Exchange (ETDEWEB)

Cerce, Luka; Pusavec, Franci; Kopac Janez [University of Ljubljana, Askerceva (Slovenia)

2015-09-15

The tool-wear of cutting tools has a very strong impact on the product quality as well as efficiency of the machining processes. Therefore, it in-the process characterization is crucial. This paper presents an innovative and reliable direct measuring procedure for measuring spatial cutting tool-wear with usage of laser profile sensor. The technique provides possibility for determination of 3D wear profiles, as advantage to currently used 2D techniques. The influence of the orientation of measurement head on the accuracy and the amount of captured reliable data was examined and the optimal setup of the measuring system was defined. Further, a special clamping system was designed to mount the measurement device on the machine tool turret. To test the measurement system, tool-life experiment was performed. Additionally, a new tool-life criterion was developed, including spatial characteristics of the tool-wear. The results showed that novel tool-wear and tool-life diagnostic represent objective and robust estimator of the machining process. Additionally, such automation of tool-wear diagnostics on machine tool provides higher productivity and quality of the machining process.

Mechanical seal assembly

Science.gov (United States)

Kotlyar, Oleg M.

2001-01-01

An improved mechanical seal assembly is provided for sealing rotating shafts with respect to their shaft housings, wherein the rotating shafts are subject to substantial axial vibrations. The mechanical seal assembly generally includes a rotating sealing ring fixed to the shaft, a non-rotating sealing ring adjacent to and in close contact with the rotating sealing ring for forming an annular seal about the shaft, and a mechanical diode element that applies a biasing force to the non-rotating sealing ring by means of hemispherical joint. The alignment of the mechanical diode with respect to the sealing rings is maintained by a series of linear bearings positioned axially along a desired length of the mechanical diode. Alternative embodiments include mechanical or hydraulic amplification components for amplifying axial displacement of the non-rotating sealing ring and transferring it to the mechanical diode.

Mechanical Seal Assembly

Energy Technology Data Exchange (ETDEWEB)

Kotlyar, Oleg M.

1999-06-18

An improved mechanical seal assembly is provided for sealing rotating shafts with respect to their shaft housings, wherein the rotating shafts are subject to substantial axial vibrations. The mechanical seal assembly generally includes a rotating sealing ring fixed to the shaft, a non-rotating sealing ring adjacent to and in close contact with the rotating sealing ring for forming an annular seal about the shaft, and a mechanical diode element that applies a biasing force to the non-rotating sealing ring by means of hemispherical joint. The alignment of the mechanical diode with respect to the sealing rings is maintained by a series of linear bearings positioned axially along a desired length of the mechanical diode. Alternative embodiments include mechanical or hydraulic amplification components for amplifying axial displacement of the non-rotating sealing ring and transferring it to the mechanical diode.

Radioactive material package seal tests

International Nuclear Information System (INIS)

Madsen, M.M.; Humphreys, D.L.; Edwards, K.R.

1990-01-01

General design or test performance requirements for radioactive materials (RAM) packages are specified in Title 10 of the US Code of Federal Regulations Part 71 (US Nuclear Regulatory Commission, 1983). The requirements for Type B packages provide a broad range of environments under which the system must contain the RAM without posing a threat to health or property. Seals that provide the containment system interface between the packaging body and the closure must function in both high- and low-temperature environments under dynamic and static conditions. A seal technology program, jointly funded by the US Department of Energy Office of Environmental Restoration and Waste Management (EM) and the Office of Civilian Radioactive Waste Management (OCRWM), was initiated at Sandia National Laboratories. Experiments were performed in this program to characterize the behavior of several static seal materials at low temperatures. Helium leak tests on face seals were used to compare the materials. Materials tested include butyl, neoprene, ethylene propylene, fluorosilicone, silicone, Eypel, Kalrez, Teflon, fluorocarbon, and Teflon/silicone composites. Because most elastomer O-ring applications are for hydraulic systems, manufacturer low-temperature ratings are based on methods that simulate this use. The seal materials tested in this program with a fixture similar to a RAM cask closure, with the exception of silicone S613-60, are not leak tight (1.0 x 10 -7 std cm 3 /s) at manufacturer low-temperature ratings. 8 refs., 3 figs., 1 tab

Backside wear in modern total knee designs.

Science.gov (United States)

Jayabalan, Prakash; Furman, Bridgette D; Cottrell, Jocelyn M; Wright, Timothy M

2007-02-01

Although modularity affords various options to the orthopedic surgeon, these benefits come at a price. The unintended bearing surface between the back surface of the tibial insert and the metallic tray results in micromotion leading to polyethylene wear debris. The objective of this study was to examine the backside wear of tibial inserts from three modern total knee designs with very different locking mechanisms: Insall-Burstein II (IB II), Optetrak, and Advance. A random sample of 71 inserts were obtained from our institution's retrieval collection and examined to assess the extent of wear, depth of wear, and wear damage modes. Patient records were also obtained to determine patient age, body mass index, length of implantation, and reason for revision. Modes of wear damage (abrasion, burnishing, scratching, delamination, third body debris, surface deformation, and pitting) were then scored in each zone from 0 to 3 (0 = 0%, 1 = 0-10%, 2 = 10-50%, and 3 = >50%). The depth of wear was subjectively identified as removal of manufacturing identification markings stamped onto the inferior surface of the polyethylene. Both Advance and IB II polyethylene inserts showed significantly higher scores for backside wear than the Optetrak inserts. All IB II and Advance implants showed evidence of backside wear, whereas 17% (5 out of 30) of the retrieved Optetrak implants had no observable wear. There were no significant differences when comparing the depth of wear score between designs. The locking mechanism greatly affects the propensity for wear and should be considered when choosing a knee implant system.

Glass sealing

Energy Technology Data Exchange (ETDEWEB)

Brow, R.K.; Kovacic, L.; Chambers, R.S. [Sandia National Labs., Albuquerque, NM (United States)

1996-04-01

Hernetic glass sealing technologies developed for weapons component applications can be utilized for the design and manufacture of fuel cells. Design and processing of of a seal are optimized through an integrated approach based on glass composition research, finite element analysis, and sealing process definition. Glass sealing procedures are selected to accommodate the limits imposed by glass composition and predicted calculations.

Tamper-indicating quantum optical seals

Energy Technology Data Exchange (ETDEWEB)

Humble, Travis S [ORNL; Williams, Brian P [ORNL

2015-01-01

Confidence in the means for identifying when tampering occurs is critical for containment and surveillance technologies. Fiber-optic seals have proven especially useful for actively surveying large areas or inventories due to the extended transmission range and flexible layout of fiber. However, it is reasonable to suspect that an intruder could tamper with a fiber-optic sensor by accurately replicating the light transmitted through the fiber. In this contribution, we demonstrate a novel approach to using fiber-optic seals for safeguarding large-scale inventories with increased confidence in the state of the seal. Our approach is based on the use of quantum mechanical phenomena to offer unprecedented surety in the authentication of the seal state. In particular, we show how quantum entangled photons can be used to monitor the integrity of a fiber-optic cable - the entangled photons serve as active sensing elements whose non-local correlations indicate normal seal operation. Moreover, we prove using the quantum no-cloning theorem that attacks against the quantum seal necessarily disturb its state and that these disturbances are immediately detected. Our quantum approach to seal authentication is based on physical principles alone and does not require the use of secret or proprietary information to ensure proper operation. We demonstrate an implementation of the quantum seal using a pair of entangled photons and we summarize our experimental results including the probability of detecting intrusions and the overall stability of the system design. We conclude by discussing the use of both free-space and fiber-based quantum seals for surveying large areas and inventories.

Mathematical Model of Piston Ring Sealing in Combustion Engine

Directory of Open Access Journals (Sweden)

Koszałka Grzegorz

2015-01-01

Full Text Available This paper presents a mathematical model of piston-rings-cylinder sealing (TPC of a combustion engine. The developed model is an itegrated model of gas flow through gaps in TPC unit, displacements and twisting motions of piston rings in ring grooves as well as generation of oil film between ring face surfaces and cylinder liner. Thermal deformations and wear of TPC unit elements as well as heat exchange between flowing gas and surrounding walls, were taken into account in the model. The paper contains descriptions of: assumptions used for developing the model, the model itself, its numerical solution as well as its computer application for carrying out simulation tests.

Rotary plug seal

International Nuclear Information System (INIS)

Ito, Koji; Abiko, Yoshihiro.

1981-01-01

Purpose: To enable fuel exchange even upon failure of regular seals and also to enable safety seal exchange by the detection of the reduction in the contact pressure of a rotary plug seal. Constitution: If one of a pair of regular tube seals for the rotary plug is failed during ordinary operation of a FBR type reactor, the reduction in the contact pressure of the seal to the plug gibbousness is detected by a pressure gauge and a solenoid valve is thereby closed. Thus, a back-up-tube seal provided above or below the tube seal is press-contacted by way of argon gas to the gibbousness to enter into operation state and lubricants are supplied from an oil tank. In such a structure, the back-up-tube seal is operated before the failure of the tube seal to enable to continue the fuel exchange work, as well as safety exchange for the tube seal. (Moriyama, K.)

Assessment of wear dependence parameters in complex model of cutting tool wear

Science.gov (United States)

Antsev, A. V.; Pasko, N. I.; Antseva, N. V.

2018-03-01

This paper addresses wear dependence of the generic efficient life period of cutting tools taken as an aggregate of the law of tool wear rate distribution and dependence of parameters of this law's on the cutting mode, factoring in the random factor as exemplified by the complex model of wear. The complex model of wear takes into account the variance of cutting properties within one batch of tools, variance in machinability within one batch of workpieces, and the stochastic nature of the wear process itself. A technique of assessment of wear dependence parameters in a complex model of cutting tool wear is provided. The technique is supported by a numerical example.

Dura Seal recommendations for nuclear power plants

International Nuclear Information System (INIS)

Anon.

1980-01-01

Reactor systems (BWR, PWR and Candu) are briefly reviewed with reference to the pumping services encountered in each system, to indicate the conditions imposed on mechanical seals for nuclear power plant liquid handling equipment. A description of the Dura Seals used in each service is included. (U.K.)

Remote video registration of seals at Rødsand seal sanctuary

DEFF Research Database (Denmark)

Edren, Susi M.C.; Teilmann, J.; Dietz, R.

This report describes the preliminary use of a remote-controlled webbased camera system in the Rødsand seal sanctuary. The camera system powered by solar and wind energy is designed to operate under extreme weather conditions. Live images and still photos are transmitted to a land station, from...

Urban gray vs. urban green vs. soil protection — Development of a systemic solution to soil sealing management on the example of Germany

International Nuclear Information System (INIS)

Artmann, Martina

2016-01-01

Managing urban soil sealing is a difficult venture due to its spatial heterogeneity and embedding in a socio-ecological system. A systemic solution is needed to tackle its spatial, ecological and social sub-systems. This study develops a guideline for urban actors to find a systemic solution to soil sealing management based on two case studies in Germany: Munich and Leipzig. Legal-planning, informal-planning, economic-fiscal, co-operative and informational responses were evaluated by indicators to proof which strategy considers the spatial complexity of urban soil sealing (systemic spatial efficiency) and, while considering spatial complexity, to assess what the key management areas for action are to reduce the ecological impacts by urban soil sealing (ecological impact efficiency) and to support an efficient implementation by urban actors (social implementation efficiency). Results suggest framing the systemic solution to soil sealing management through a cross-scale, legal-planning development strategy embedded in higher European policies. Within the socio-ecological system, the key management area for action should focus on the protection of green infrastructure being of high value for actors from the European to local scales. Further efforts are necessary to establish a systemic monitoring concept to optimize socio-ecological benefits and avoid trade-offs such as between urban infill development and urban green protection. This place-based study can be regarded as a stepping stone on how to develop systemic strategies by considering different spatial sub-targets and socio-ecological systems. - Highlights: • Urban soil sealing management is spatially complex. • The legal-planning strategy supports a systemic sealing management. • Urban green infrastructure protection should be in the management focus. • Soil protection requires policies from higher levels of government. • A systemic urban soil sealing monitoring concept is needed.

Urban gray vs. urban green vs. soil protection — Development of a systemic solution to soil sealing management on the example of Germany

Energy Technology Data Exchange (ETDEWEB)

Artmann, Martina, E-mail: m.artmann@ioer.de

2016-07-15

Managing urban soil sealing is a difficult venture due to its spatial heterogeneity and embedding in a socio-ecological system. A systemic solution is needed to tackle its spatial, ecological and social sub-systems. This study develops a guideline for urban actors to find a systemic solution to soil sealing management based on two case studies in Germany: Munich and Leipzig. Legal-planning, informal-planning, economic-fiscal, co-operative and informational responses were evaluated by indicators to proof which strategy considers the spatial complexity of urban soil sealing (systemic spatial efficiency) and, while considering spatial complexity, to assess what the key management areas for action are to reduce the ecological impacts by urban soil sealing (ecological impact efficiency) and to support an efficient implementation by urban actors (social implementation efficiency). Results suggest framing the systemic solution to soil sealing management through a cross-scale, legal-planning development strategy embedded in higher European policies. Within the socio-ecological system, the key management area for action should focus on the protection of green infrastructure being of high value for actors from the European to local scales. Further efforts are necessary to establish a systemic monitoring concept to optimize socio-ecological benefits and avoid trade-offs such as between urban infill development and urban green protection. This place-based study can be regarded as a stepping stone on how to develop systemic strategies by considering different spatial sub-targets and socio-ecological systems. - Highlights: • Urban soil sealing management is spatially complex. • The legal-planning strategy supports a systemic sealing management. • Urban green infrastructure protection should be in the management focus. • Soil protection requires policies from higher levels of government. • A systemic urban soil sealing monitoring concept is needed.

Verification of Drift Seal Systems at the Morsleben Repository, Germany - Proof of Technical Feasibility and Functionality

International Nuclear Information System (INIS)

Wollrath, Juergen; Mauke, R.; Siemann, M.

2014-01-01

The Morsleben repository (ERAM) for low- and intermediate-level mainly short-lived radioactive wastes is located in a former salt mine. The closure concept is based on extensive backfilling with salt concrete complemented by seals that should prevent the penetration of solution into the waste emplacement areas and the emission of radionuclides out of these areas. The drift seals located in rock salt are made up of one or more segments of salt concrete in lengths between 25 m and 30 m. The sealing structure consists of three components: the seal body made of salt concrete, the contact zone between the seal body and the surrounding rock salt and the rock salt excavation damaged zone (EDZ). To demonstrate the feasibility of constructing such a seal structure an in-situ experiment is performed and a test drift and an accompanying parallel drift have been excavated for the experiment. The trial construction also comprises geotechnical instrumentation for stress, strain, displacement, temperature and pore pressure measurements and a comprehensive site investigation programme has been carried out, notably with regard to the stress state and the convergence behaviour of the surrounding rock salt. In addition to in-situ measurements, test specimens from different areas of the construction have been drilled and tested (strength and permeability). The pressure chamber has also been filled with brine solution to ascertain the permeability of the whole sealing structure. Another in-situ experiment is planned for the seal to be built in the non-creeping anhydrite. Both in-situ experiments will aid to prove the technical feasibility and functionality of the drift seal systems

Microstructure Characterization and Wear-Resistant Properties Evaluation of an Intermetallic Composite in Ni–Mo–Si System

Directory of Open Access Journals (Sweden)

Boyuan Huang

2017-02-01

Full Text Available Intermetallic compounds have been studied for their potential application as structural wear materials or coatings on engineering steels. In the present work, a newly designed intermetallic composite in a Ni–Mo–Si system was fabricated by arc-melting process with commercially pure metal powders as starting materials. The chemical composition of this intermetallic composite is 45Ni–40Mo–15Si (at %, selected according to the ternary alloy diagram. The microstructure was characterized using optical microscopy (OM, scanning electron microscopy (SEM, X-ray diffraction (XRD, and energy dispersive spectroscopy (EDS, and the wear-resistant properties at room temperature were evaluated under different wear test conditions. Microstructure characterization showed that the composite has a dense and uniform microstructure. XRD results showed that the intermetallic composite is constituted by a binary intermetallic compound NiMo and a ternary Mo2Ni3Si metal silicide phase. Wear test results indicated that the intermetallic composite has an excellent wear-resistance at room-temperature, which is attributed to the high hardness and strong atomic bonding of constituent phases NiMo and Mo2Ni3Si.

Sealing performance of a magnetic fluid seal for rotary blood pumps.

Science.gov (United States)

Mitamura, Yoshinori; Takahashi, Sayaka; Kano, Kentaro; Okamoto, Eiji; Murabayashi, Shun; Nishimura, Ikuya; Higuchi, Taka-Aki

2009-09-01

A magnetic fluid (MF) for a rotary blood pump seal enables mechanical contact-free rotation of the shaft and, hence, has excellent durability. The performance of a MF seal, however, has been reported to decrease in liquids. We have developed a MF seal that has a "shield" mechanism and a new MF with a higher magnetization of 47.9 kA/m. The sealing performance of the MF seal installed in a rotary blood pump was studied. Under the condition of continuous flow, the MF seal remained in perfect condition against a pressure of 298 mm Hg (pump flow rate: 3.96 L/min). The seal was also perfect against a pressure of 170 mm Hg in a continuous flow of 3.9 L/min for 275 days. We have developed a MF seal that works in liquid against clinically used pressures. The MF seal is promising as a shaft seal for rotary blood pumps.

Improvement in oil seal performance of gas compressor in HTTR

International Nuclear Information System (INIS)

Oyama, Sunao; Hamamoto, Shimpei; Nemoto, Takahiro; Sekita, Kenji; Isozaki, Minoru; Emori, Kouichi; Ohta, Yukimaru; Mizushima, Toshihiko; Kaneshiro, Noriyuki; Ito, Yoshiteru; Yamamoto, Hideo

2007-08-01

High-Temperature engineering Test Reactor (HTTR) built by Japan Atomic Energy Agency (JAEA) has reciprocating compressor commonly used to extract and discharge helium gas into primary/secondary coolant helium loop from helium purification system. Piston rod seal of the compressor consist of several components to prevent coolant leak. However, rod seal system has weak reliability during long term operation due to repeated leakage of seal oil in operation. As a result of investigations, leakage's root is found in that seal were used in a range beyond limit sliding properties of seal material. For this reason, a lip of the seal was worn and transformed itself and was not able to sustain a seal function. Therefore, through tests using facility actual equipment for endurance of candidate materials, one seal material were chosen for long term operation. (author)

Spray sealing: A breakthrough in integral fuel tank sealing technology

Science.gov (United States)

Richardson, Martin D.; Zadarnowski, J. H.

1989-11-01

In a continuing effort to increase readiness, a new approach to sealing integral fuel tanks is being developed. The technique seals potential leak sources by spraying elastomeric materials inside the tank cavity. Laboratory evaluations project an increase in aircraft supportability and reliability, an improved maintainability, decreasing acquisition and life cycle costs. Increased usable fuel volume and lower weight than conventional bladders improve performance. Concept feasibility was demonstrated on sub-scale aircraft fuel tanks. Materials were selected by testing sprayable elastomers in a fuel tank environment. Chemical stability, mechanical properties, and dynamic durability of the elastomer are being evaluated at the laboratory level and in sub-scale and full scale aircraft component fatigue tests. The self sealing capability of sprayable materials is also under development. Ballistic tests show an improved aircraft survivability, due in part to the elastomer's mechanical properties and its ability to damp vibrations. New application equipment, system removal, and repair methods are being investigated.

Seal analysis technology for reactor pressure vessel

International Nuclear Information System (INIS)

Zheng Liangang; Zhang Liping; Yang Yu; Zang Fenggang

2009-01-01

There is the coolant with radiation, high temperature and high pressure in the reactor pressure vessel (RPV). It is closely correlated to RPV sealing capability whether the whole nuclear system work well or not. The aim of this paper is to study the seal analysis method and technology, such as the pre-tensioning of the bolt, elastoplastic contact and coupled technology of thermal and structure. The 3 D elastoplastic seal analysis method really and generally consider the loads and model the contact problem with friction between the contact plates. This method is easier than the specialized seal program and used widely. And it is more really than the 2 D seal analysis method. This 3 D elastoplastic seal analysis method has been successfully used in the design and analysis of RPV. (authors)

Salt brickwork as long-term sealing in salt formations

International Nuclear Information System (INIS)

Walter, F.; Yaramanci, U.

1993-01-01

Radioactive wastes can be disposed of in deep salt formations. Rock salt is a suitable geologic medium because of its unique characteristics. Open boreholes, shafts and drifts are created to provide physical access to the repository. Long-term seals must be emplaced in these potential pathways to prevent radioactive release into the biosphere. The sealing materials must be mechanically and, most important, geochemically stable within the host rock. Salt bricks made from compressed salt-powder are understood to be the first choice long-term sealing material. Seals built of salt bricks will be ductile. Large sealing systems are built by combining the individual bricks with mortar. Raw materials for mortar are fine-grained halite powder and ground saliferous clay. This provides for the good adhesive strength of the mortar to the bricks and the high shear-strength of the mortar itself. To test the interaction of rock salt with an emplaced long-term seal, experiments will be carried out in situ, in the Asse salt mine in Germany. Simple borehole sealing experiments will be performed in horizontal holes and a complicated drift sealing experiment is planned, to demonstrate the technology of sealing a standard size drift or shaft inside a disturbed rock mass. Especially, the mechanical stability of the sealing system has to be demonstrated

A novel approach for quality control system using sensor fusion of infrared and visual image processing for laser sealing of food containers

Science.gov (United States)

Al-Habaibeh, A.; Shi, F.; Brown, N.; Kerr, D.; Jackson, M.; Parkin, R. M.

2004-10-01

This paper presents a new mechatronic approach of using infrared thermography combined with image processing for the quality control of a laser sealing process for food containers. The suggested approach uses an online infrared system to assess the heat distribution within the container seal in order to guarantee the integrity of the process. Visual image processing is then used for quality assurance to guarantee optimum sealing. The results described in this paper show examples of the capability of the condition monitoring system to detect faults in the sealing process. The results found indicate that the suggested approach could form an effective quality control and assurance system.

Pseudomembranous candidiasis in patient wearing full denture

Directory of Open Access Journals (Sweden)

Nurdiana Nurdiana

2009-06-01

Full Text Available Background: Oral candidiasis is a common opportunistic infection of the oral cavity caused by an overgrowth of Candida species, the commonest being Candida albicans. Candida albicans is a harmless commensal organism inhabiting the mouths but it can change into pathogen and invade tissue and cause acute and chronic disease. Dentures predispose to infection with Candida in as many as 65% of elderly people wearing full upper dentures. Purpose: The purpose of this case report is to discuss thrush in patient wearing full denture which rapidly developed. Case: This paper report a case of 57 year-old man who came to the Oral Medicine Clinic Faculty of Dentistry Airlangga University with clinical appearance of pseudomembranous candidiasis (thrush. Case Management: Diagnosis of this case is confirmed with microbiology examination. Patient was wearing full upper dentures, and from anamnesis known that patient wearing denture for 24 hours and he had poor oral hygiene. Patient was treated with topical (nystatin oral suspension and miconazole oral gel and systemic (ketoconazole antifungal. Patient also instructed not to wear his denture and cleaned white pseudomembrane on his mouth with soft toothbrush. Conclusion: Denture, habit of wearing denture for 24 hours, and poor oral hygiene are predisposing factors of thrush and it can healed completely after treated with topical and systemic antifungal.

Sliding seal materials for low heat rejection engines

Science.gov (United States)

Beaty, Kevin; Lankford, James; Vinyard, Shannon

1989-01-01

Sliding friction coefficients and wear rates of promising piston seal materials were measured under temperature, environmental, velocity, and loading conditions that are representative of the low heat rejection (LHR) diesel engine environment. These materials included carbides, oxides, and nitrides. In addition, silicon nitride and partially stablized zirconia disks (cylinder liners) were ion-implanted with TiNi, Ni, Co, and Cr, and subsequently run against carbide pins (piston rings), with the objective of producing reduced friction via solid lubrication at elevated temperature. Friction and wear measurements were obtained using pin-on-disk laboratory experiments and a unique engine friction test rig. Unmodified ceramic sliding couples were characterized at all temperatures by friction coefficients of 0.24 and above during the pin-on-disk tests. The coefficient at 800 C in an oxidizing environment was reduced to below 0.1, for certain material combination, by the ion-implantation of TiNi or Co. This beneficial effect was found to derive from the lubricious Ti, Ni, and Co oxides. Similar results were demonstrated on the engine friction test rig at lower temperatures. The structural integrity and feasibility of engine application with the most promising material combination were demonstrated during a 30-hour single-cylinder, direct-injection diesel engine test.

Electronic self-monitoring seal

International Nuclear Information System (INIS)

Campbell, J.W.

1978-01-01

The Electronic Self-Monitoring Seal is a new type of security seal which allows continuous verification of the seal's identity and status. The identity information is a function of the individual seal, time, and seal integrity. A description of this seal and its characteristics are presented. Also described are the use cycle for the seal and the support equipment for programming and verifying the seal

Security seal

Science.gov (United States)

Gobeli, Garth W.

1985-01-01

Security for a package or verifying seal in plastic material is provided by a print seal with unique thermally produced imprints in the plastic. If tampering is attempted, the material is irreparably damaged and thus detectable. The pattern of the imprints, similar to "fingerprints" are recorded as a positive identification for the seal, and corresponding recordings made to allow comparison. The integrity of the seal is proved by the comparison of imprint identification records made by laser beam projection.

Mechanical seal program

International Nuclear Information System (INIS)

Lowery, G.B.

1983-01-01

The experimental plans and timing for completion of the mechanical seal program for both the slurry and transfer pumps are given. The slurry pump seal program will be completed by April 1984 with turnover of two seals in pumps to SRP Tank 15H. Transfer pump seal design will be released for plant use by May 1984. Also included are various other pump and seal related tests

Secondary seal effects in hydrostatic non-contact seals for reactor coolant pump shaft

International Nuclear Information System (INIS)

Fujita, T.; Koga, T.; Tanoue, H.; Hirabayashi, H.

1987-01-01

The paper presents a seal flow analysis in a hydrostatic non-contact seal for a PWR coolant pump shaft. A description is given of the non-contact seal for the reactor coolant pump. Results are presented for a distortion analysis of the seal ring, along with the seal flow characteristics and the contact pressure profiles of the secondary seals. The results of the work confirm previously reported findings that the seal ring distortion is sensitive to the o-ring location (which was placed between the ceramic seal face and the seal ring retainer). The paper concludes that the seal flow characteristics and the tracking performance depend upon the dynamic properties of the secondary seal. (U.K.)

Design optimization of seal structure for sealing liquid by magnetic fluids

International Nuclear Information System (INIS)

Liu Tonggang; Cheng Yusheng; Yang Zhiyi

2005-01-01

The durability of the magnetic fluid seal clearly decreases when sealing another liquid because of the interface instability caused by the applied magnetic field and the velocity difference of the two liquids. With an intention to establish a stable interface during sealing liquid, a new magnetic fluid seal was developed in this paper. The parameters of the structure were optimized by a simulation apparatus. And the magnetic fluid seal designed based on the optimum parameters shows good performance and long life for sealing lubricating oil

High performance corrosion and wear resistant composite titanium nitride layers produced on the AZ91D magnesium alloy by a hybrid method

Directory of Open Access Journals (Sweden)

Michał Tacikowski

2014-09-01

Full Text Available Composite, diffusive titanium nitride layers formed on a titanium and aluminum sub-layer were produced on the AZ91D magnesium alloy. The layers were obtained using a hybrid method which combined the PVD processes with the final sealing by a hydrothermal treatment. The microstructure, resistance to corrosion, mechanical damage, and frictional wear of the layers were examined. The properties of the AZ91D alloy covered with these layers were compared with those of the untreated alloy and of some engineering materials such as 316L stainless steel, 100Cr6 bearing steel, and the AZ91D alloy subjected to commercial anodizing. It has been found that the composite diffusive nitride layer produced on the AZ91D alloy and then sealed by the hydrothermal treatment ensures the corrosion resistance comparable with that of 316L stainless steel. The layers are characterized by higher electrochemical durability which is due to the surface being overbuilt with the titanium oxides formed, as shown by the XPS examinations, from titanium nitride during the hydrothermal treatment. The composite titanium nitride layers exhibit high resistance to mechanical damage and wear, including frictional wear which is comparable with that of 100Cr6 bearing steel. The performance properties of the AZ91D magnesium alloy covered with the composite titanium nitride coating are substantially superior to those of the alloy subjected to commercial anodizing which is the dominant technique employed in industrial practice.

Leak detection of KNI seals

International Nuclear Information System (INIS)

Baranyai, G.; Peter, A.; Windberg, P.

1990-03-01

In Unit 3 and 4 of the Paks Nuclear Power Plant, Hungary, KNI type seals are used as lead-throughs with conical nickel sealing rings. Their failure can be critical for the operation of the reactor. An Acoustical Leak Detection System (ALDS) was constructed and tested for the operational testing of the seals. Some individual papers are presented in this collection on the calibration and testing of the ALDS intended to be placed on the top of the reactor vessels. The papers include simulation measurements of Unit 3 of NPP, laboratory experiments, evaluation of measurements, and further development needs with the ALDS. (R.P.) 50 figs.; 19 tabs

Vibrational characteristics and wear of fuel rods

International Nuclear Information System (INIS)

Schmugar, K.L.

1977-01-01

Fuel rod wear, due to vibration, is a continuing concern in the design of liquid-cooled reactors. In my report, the methodology and models that are used to predict fuel rod vibrational response and vibratory wear, in a light water reactor environment, are discussed. This methodology is being followed at present in the design of Westinghouse Nuclear Fuel. Fuel rod vibrations are expressed as the normal bending modes, and sources of rod vibration are examined with special emphasis on flow-induced mechanisms in the stable flow region. In a typical Westinghouse PWR fuel assembly design, each fuel rod is supported at multiple locations along the rod axis by a square-shaped 'grid cell'. For a fuel rod /grid support system, the development of small oscillatory motions, due to fluid flow at the rod/grid interface, results in material wear. A theoretical wear mode is developed using the Archard Theory of Adhesive Wear as the basis. Without question certainty, fretting wear becomes a serious problem if it progresses to the stage where the fuel cladding is penetrated and fuel is exposed to the coolant. Westinghouse fuel is designed to minimize fretting wear by limiting the relative motion between the fuel rod and its supports. The wear producing motion between the fuel rod and its supports occurs when the vibration amplitude exceeds the slippage threshold amplitude

Properties of Sealing Materials in Groundwater Wells

DEFF Research Database (Denmark)

Köser, Claus

pellets as sealing material in groundwater wells. The way and the pattern, in which bentonite pellets are deposited, have been shown to have an effect on the swelling pressure of the bentonite seal. During the transport phase of pellets from the terrain to a given sedimentation depth, a sorting process......) into densities for clay/water systems has been developed. This method has successfully been used to evaluate e.g., macroporosity, homogenization of the bentonite seal during the hydration of water, hydraulic conductivity and the creation of channels in the bentonite seals. Based on the results obtained...

Dynamic SEM wear studies of tungsten carbide cermets. [friction and wear experiments

Science.gov (United States)

Brainard, W. A.; Buckley, D. H.

1975-01-01

Dynamic friction and wear experiments were conducted in a scanning electron microscope. The wear behavior of pure tungsten carbide and composite with 6 and 15 weight percent cobalt binder was examined, and etching of the binder was done to selectively determine the role of the binder in the wear process. Dynamic experiments were conducted as the tungsten carbide (WC) and bonded WC cermet surfaces were transversed by a 50 micron radiused diamond stylus. These studies show that the predominant wear process in WC is fracture initiated by plastic deformation, and the wear of the etched cermets is similar to pure WC. The presence of the cobalt binder reduces both friction and wear. The cementing action of the cobalt reduces granular separation, and promotes a dense polished layer because of its low shear strength film-forming properties. The wear debris generated from unetched surface is approximately the same composition as the bulk.

Assessment of wear facets produced by the ACTA wear machine

DEFF Research Database (Denmark)

Benetti, Ana R; Larsen, Liselotte; Dowling, Adam H

2016-01-01

. The mean wear depth was measured using the traditionally employed 2D and compared with the 3D profilometric (digital) techniques. Data were submitted to analyses of variance, Tukey's post hoc tests and Independent Samples Student's t-tests (where appropriate) at p...OBJECTIVE: To investigate the use of a three-dimensional (3D) digital scanning method in determining the accuracy of the wear performance parameters of resin-based composites (RBCs) determined using a two-dimensional (2D) analogue methodology following in-vitro testing in an Academisch Centrum...... for Tandheelkunde Amsterdam (ACTA) wear machine. METHODS: Specimens compatible with the compartments of the ACTA wear machine specimen wheel (n=10) were prepared from one commercial and four experimental RBCs. The RBC specimens were rotated against an antagonist wheel in a food-like slurry for 220,000 wear cycles...

Polymer wear evaluation

DEFF Research Database (Denmark)

Lagerbon, Mikkel; Sivebæk, Ion Marius

2012-01-01

Polymer wear plays an increasing role in manufacturing of machine parts for e.g. medical devices. Some of these have an expected lifetime of five to eight years during which very little wear of the components is acceptable. Too much wear compromises the dosage accuracy of the device and thereby...... the safety of the patients. Prediction of the wear of polymers is complicated by the low thermal conductivity of this kind of material. It implies that any acceleration of testing conditions by increased contact pressure and/or sliding velocity will make the polymer fail due to exaggerated heat buildup....... This is not the kind of wear observed in medical devices. In the present work a method was developed capable of evaluating the wear progression in polymer-polymer contacts. The configuration of the setup is injection moulded specimens consisting of an upper part having a toroid shape and a lower flat part. The sliding...

Seroprevalence of Antibodies against Seal Influenza A(H10N7) Virus in Harbor Seals and Gray Seals from the Netherlands.

Science.gov (United States)

Bodewes, Rogier; Rubio García, Ana; Brasseur, Sophie M; Sanchez Conteras, Guillermo J; van de Bildt, Marco W G; Koopmans, Marion P G; Osterhaus, Albert D M E; Kuiken, Thijs

2015-01-01

In the spring and summer 2014, an outbreak of seal influenza A(H10N7) virus infection occurred among harbor seals (Phoca vitulina) off the coasts of Sweden and Denmark. This virus subsequently spread to harbor seals off the coasts of Germany and the Netherlands. While thousands of seals were reported dead in Sweden, Denmark and Germany, only a limited number of seals were found dead in the Netherlands. To determine the extent of exposure of seals in the Netherlands to influenza A/H10N7 virus, we measured specific antibody titers in serum samples from live-captured seals and seals admitted for rehabilitation in the Netherlands by use of a hemagglutination inhibition assay and an ELISA. In harbor seals in 2015, antibodies against seal influenza A(H10N7) virus were detected in 41% (32 out of 78) pups, 10% (5 out of 52) weaners, and 58% (7 out of 12) subadults or adults. In gray seals (Halichoerus grypus) in 2015, specific antibodies were not found in the pups (n = 26), but in 26% (5 out of 19) of the older animals. These findings indicate that, despite apparent low mortality, infection with seal influenza A(H10N7) virus was geographically widespread and also occurred in grey seals.

Calculation of density and permeability of compacted crushed salt within an engineered shaft sealing system

International Nuclear Information System (INIS)

Loken, M.; Statham, W.

1997-01-01

Crushed salt from the host Salado Formation is proposed as a sealing material in one component of a multicomponent seal system design for the shafts of the Waste Isolation Pilot Plant (WIPP), a mined geological repository for storage and disposal of transuranic radioactive wastes located near Carlsbad, New Mexico. The crushed salt will be compacted and placed at a density approaching 90% of the intact density of the host Salado salt. Creep closure of the shaft will further compact the crushed salt over time, thereby reducing the crushed-salt permeability from the initial state and creating an effective long-term seal. A structural model and a fluid flow model have been developed to provide an estimate of crushed-salt reconsolidation rate as a function of depth, time, and pore pressure. Model results are obtained in terms of crushed-salt permeability as a function of time and depth within the salt column. Model results indicate that average salt column permeability will be reduced to 3.3 x 10 -20 m 2 in about 100 years, which provides for an acceptable long-term seal component

Abrasive wear of ceramic wear protection at ambient and high temperatures

Science.gov (United States)

Varga, M.; Adam, K.; Tumma, M.; Alessio, K. O.

2017-05-01

Ceramic wear protection is often applied in abrasive conditions due to their excellent wear resistance. This is especially necessary in heavy industries conveying large amounts of raw materials, e.g. in steel industry. Some plants also require material transport at high temperatures and velocities, making the need of temperature stable and abrasion resistant wear protection necessary. Various types and wear behaviour of ceramic protection are known. Hence, the goal of this study is to identify the best suitable ceramic materials for abrasive conditions in harsh environments at temperatures up to 950°C and severe thermal gradients. Chamottes, known for their excellent thermal shock resistance are compared to high abrasion resistant ceramic wear tiles and a cost efficient cement-bounded hard compound. Testing was done under high-stress three-body abrasion regime with a modified ASTM G65 apparatus enabling for investigations up to ~950°C. Thereto heated abrasive is introduced into the wear track and also preheated ceramic samples were used and compared to ambient temperature experiments. Results indicate a significant temperature influence on chamottes and the hard compound. While the chamottes benefit from temperature increase, the cement-bounded hard compound showed its limitation at abrasive temperatures of 950°C. The high abrasion resistant wear tiles represented the materials with the best wear resistance and less temperature influence in the investigated range.

Carbon-Based Wear Coatings: Properties and Applications

Science.gov (United States)

Miyoshi, Kazuhisa

2003-01-01

The technical function of numerous engineering systems - such as vehicles, machines, and instruments - depends on the processes of motion and on the surface systems. Many processes in nature and technology depend on the motion and dynamic behavior of solids, liquids, and gases. Smart surface systems are essential because of the recent technological push toward higher speeds, loads, and operating temperatures; longer life; lighter weight and smaller size (including nanotechnology); and harsh environments in mechanical, mechatronic, and biomechanical systems. If proper attention is not given to surface systems, then vehicles, machines, instruments, and other technical systems could have short lives, consume excessive energy, experience breakdowns, result in liabilities, and fail to accomplish their missions. Surface systems strongly affect our national economy and our lifestyles. At the NASA Glenn Research Center, we believe that proper attention to surface systems, especially in education, research, and application, could lead to economic savings of between 1.3 and 1.6 percent of the gross domestic product. Wear coatings and surface systems continue to experience rapid growth as new coating and surface engineering technologies are discovered, more cost-effective coating and surface engineering solutions are developed, and marketers aggressively pursue, uncover, and exploit new applications for engineered surface systems in cutting tools and wear components. Wear coatings and smart surface systems have been used widely in industrial, consumer, automotive, aerospace, and biomedical applications. This presentation expresses the author's views of and insights into smart surface systems in wear coatings. A revolution is taking place in carbon science and technology. Diamond, an allotrope of carbon, joins graphite, fullerenes, and nanotubes as its major pure carbon structures. It has a unique combination of extreme properties: hardness and abrasion resistance; adhesion

In situ investigation of the long-term sealing system as component of dam construction (Dam project)

International Nuclear Information System (INIS)

1995-01-01

The project ''In situ investigation of the long term sealing system as a component of a Dam Construction'' started on April 1991. The main objectives of the research to be developed by DIT-UPC group is to model and validate the effects of multiphase flow through the components of the long-term seal and at the interface between the seal and the host rock. These include the following main tasks: -Task 1: State of the art-review -Task 2: Laboratory work -Task 3: Modelling -Task 4: Code verification -Task 5: Validation From these tasks, the main research directions that have been followed are: Constitutive modelling of the mechanical behaviour of porous salt aggregates. Development of a theoretical framework for the study and charaterization of the coupled hydro-thermo-mechanical behaviour of a porous/non-porous saline system. This includes both, establishing the governing equations and the adoption of constitutive laws. The final objective is the development of a numerical simulator able to handle problems in saline environments

In situ investigation of the long-term sealing system as component of dam construction (Dam project)

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-12-31

The project ``In situ investigation of the long term sealing system as a component of a Dam Construction`` started on April 1991. The main objectives of the research to be developed by DIT-UPC group is to model and validate the effects of multiphase flow through the components of the long-term seal and at the interface between the seal and the host rock. These include the following main tasks: -Task 1: State of the art-review -Task 2: Laboratory work -Task 3: Modelling -Task 4: Code verification -Task 5: Validation From these tasks, the main research directions that have been followed are: Constitutive modelling of the mechanical behaviour of porous salt aggregates. Development of a theoretical framework for the study and charaterization of the coupled hydro-thermo-mechanical behaviour of a porous/non-porous saline system. This includes both, establishing the governing equations and the adoption of constitutive laws. The final objective is the development of a numerical simulator able to handle problems in saline environments.

Calculation of wear (f.i. wear modulus) in the plastic cup of a hip joint prosthesis

NARCIS (Netherlands)

Ligterink, D.J.

1975-01-01

The wear equation is applied to the wear process in a hip joint prosthesis and a wear modulus is defined. The sliding distance, wear modulus, wear volume, wear area, contact angle and the maximum normal stress were calculated and the theoretical calculations applied to test results. During the wear

A seal analyzer for testing container integrity

International Nuclear Information System (INIS)

McDaniel, P.; Jenkins, C.

1988-01-01

This paper reports on the development of laboratory and production seal analyzer that offers a rapid, nondestructive method of assuring the seal integrity of virtually any type of single or double sealed container. The system can test a broad range of metal cans, drums and trays, membrane-lidded vessels, flexible pouches, aerosol containers, and glass or metal containers with twist-top lids that are used in the chemical/pesticide (hazardous materials/waste), beverage, food, medical and pharmaceutical industries

Assessment of the progression of tooth wear on dental casts

NARCIS (Netherlands)

Vervoorn-Vis, G.M.G.J.; Wetselaar, P.; Koutris, M.; Visscher, C.M.; Evälahti, M.; Ahlberg, J.; Lobbezoo, F.

2015-01-01

Many methods are available for the grading of tooth wear, but their ability to assess the progression of wear over time has not been studied frequently. The aim was to assess whether the occlusal/incisal grading scale of the Tooth Wear Evaluation System (TWES) was sensitive enough for the detection

Wear determination in braking systems by radioisotopes

International Nuclear Information System (INIS)

Spruch, W.

1979-01-01

Friction and wear behaviour of friction couples has been tested applying loads and sliding speeds. The determination was carried out by direct measurements of the lining material and by surface activation of the opposite material with protons. The application limits of several braking materials could be determined and compared

Nuclear waste vault sealing

International Nuclear Information System (INIS)

Gyenge, M.

1980-01-01

A nuclear waste vault must be designed and built to ensure adequate isolation of the nuclear wastes from human contact. Consequently, after a vault has been fully loaded, it must be adequately sealed off to prevent radionuclide migration which may be provided by circulating groundwater. Vault sealing entails four major aspects, i.e.: (a) vault grouting; (b) borehole sealing; (c) buffer packing; and (d) backfilling. Of particular concern in vault sealing are the physical and chemical properties of the sealing material, its long-term durability and stability, and the techniques used for its emplacement. Present sealing technology and sealing materials are reviewed in terms of the particular needs of vault sealing. Areas requiring research and development are indicated

Nozzle seal

International Nuclear Information System (INIS)

Herman, R.F.

1977-01-01

In an illustrative embodiment of the invention, a nuclear reactor pressure vessel, having an internal hoop from which the heated coolant emerges from the reactor core and passes through to the reactor outlet nozzles, is provided with sealing members operatively disposed between the outlet nozzle and the hoop. The sealing members are biased against the pressure vessel and the hoop and are connected by a leak restraining member establishing a leak-proof condition between the inlet and outlet coolants in the region about the outlet nozzle. Furthermore, the flexible responsiveness of the seal assures that the seal will not structurally couple the hoop to the pressure vessel

Nozzle seal

International Nuclear Information System (INIS)

Walling, G.A.

1977-01-01

In an illustrative embodiment of the invention, a nuclear reactor pressure vessel, having an internal hoop from which the heated coolant emerges from the reactor core and passes through to the reactor outlet nozzles, is provided with sealing rings operatively disposed between the outlet nozzles and the hoop. The sealing rings connected by flexible members are biased against the pressure vessel and the hoop, establishing a leak-proof condition between the inlet and outlet coolants in the region about the outlet nozzle. Furthermore, the flexible responsiveness of the seal assures that the seal will not structurally couple the hoop to the pressure vessel. 4 claims, 2 figures

Flexible ring seal

International Nuclear Information System (INIS)

Abbes, Claude; Gournier, Andre; Rouaud, Christian; Villepoix, Raymond de.

1976-01-01

The invention concerns a flexible metal ring seal, able to ensure a perfect seal between two bearings due to the crushing and elastic deformation properties akin to similar properties in elastomers. Various designs of seal of this kind are already known, particularly a seal made of a core formed by a helical wire spring with close-wound turns and with high axial compression ratio, closed on itself and having the shape of an annulus. This wire ring is surrounded by at least one envelope having at rest the shape of a toroidal surface of which the generating circle does not close on itself. In a particular design mode, the seal in question can include, around the internal spring, two envelopes of which one in contact with the spring is composed of a low ductility elastic metal, such as mild steel or stainless steel and the other is, on the contrary, made of a malleable metal, such as copper or nickel. The first envelope evenly distributes the partial crushing of the spring, when the seal is tightened, on the second envelope which closely fits the two surfaces between which the seal operates. The stress-crushing curve characteristic of the seal comprises two separate parts, the first with a relatively sharp slope corresponds to the start of the seal compression phase, enabling at least some of these curves to reach the requisite seal threshold very quickly, then, beyond this, a second part, practically flat, where the stress is appreciably constant for a wide operating bracket [fr

Active Infrared Thermography for Seal Contamination Detection in Heat-Sealed Food Packaging

Directory of Open Access Journals (Sweden)

Karlien D’huys

2016-11-01

Full Text Available Packaging protects food products from environmental influences, assuring quality and safety throughout shelf life if properly performed. Packaging quality depends on the quality of the packaging material and of the closure or seal. A common problem possibly jeopardizing seal quality is the presence of seal contamination, which can cause a decreased seal strength, an increased packaging failure risk and leak formation. Therefore, early detection and removal of seal contaminated packages from the production chain is crucial. In this work, a pulsed-type active thermography method using the heated seal bars as an excitation source was studied for detecting seal contamination. Thermal image sequences of contaminated seals were recorded shortly after sealing. The detection performances of six thermal image processing methods, based on a single frame, a fit of the cooling profiles, thermal signal reconstruction, pulsed phase thermography, principal component thermography and a matched filter, were compared. High resolution digital images served as a reference to quantify seal contamination, and processed thermal images were mapped to these references. The lowest detection limit (equivalent diameter 0.60 mm was obtained for the method based on a fit of the cooling profiles. Moreover, the detection performance of this method did not depend strongly on the time after sealing at which recording of the thermal images was started, making it a robust and generally applicable method.

Wear monitoring of protective nitride coatings using image processing

DEFF Research Database (Denmark)

Rasmussen, Inge Lise; Guibert, M.; Belin, M.

2010-01-01

-meter with up to 105 19 repetitive cycles, eventually leaving the embedded TiN signal layer uncovered at the bottom the wear scar. 20 The worn surface was characterized by subsequent image processing. A color detection of the wear scar with 21 the exposed TiN layer by a simple optical imaging system showed......A double-layer model system, consisting of a thin layer of tribological titanium aluminum nitride (TiAlN) on 17 top of titanium nitride (TiN), was deposited on polished 100Cr6 steel substrates. The TiAlN top-coatings 18 were exposed to abrasive wear by a reciprocating wear process in a linear tribo...... a significant increase up to a factor of 2 of 22 the relative color values from the TiAlN top layers to the embedded TiN signal layers. This behavior agrees 23 well with the results of reflectance detection experiment with a red laser optical system on the same system. 24 Thus we have demonstrated that image...

Milling tool wear diagnosis by feed motor current signal using an artificial neural network

Energy Technology Data Exchange (ETDEWEB)

Khajavi, Mehrdad Nouri; Nasernia, Ebrahim; Rostaghi, Mostafa [Dept. of Mechanical Engineering, Shahid Rajaee Teacher Training University, Tehran (Iran, Islamic Republic of)

2016-11-15

In this paper, a Multi-layer perceptron (MLP) neural network was used to predict tool wear in face milling. For this purpose, a series of experiments was conducted using a milling machine on a CK45 work piece. Tool wear was measured by an optical microscope. To improve the accuracy and reliability of the monitoring system, tool wear state was classified into five groups, namely, no wear, slight wear, normal wear, severe wear and broken tool. Experiments were conducted with the aforementioned tool wear states, and different machining conditions and data were extracted. An increase in current amplitude was observed as the tool wear increased. Furthermore, effects of parameters such as tool wear, feed, and cut depth on motor current consumption were analyzed. Considering the complexity of the wear state classification, a multi-layer neural network was used. The root mean square of motor current, feed, cut depth, and tool rpm were chosen as the input and amount of flank wear as the output of MLP. Results showed good performance of the designed tool wear monitoring system.

Compliant seal development

Science.gov (United States)

Hendricks, Robert C.

1993-10-01

The compliant metallic seal combines the noncontact feature of the labyrinth seal, the low leakage of a mechanical seal, and the compliant nature of the brush seal. It consists of several thin metallic elements or leaves mounted within a ring which is press fit into the housing, and in form, sort of resembles a lip seal sections wiping the shaft. A second set of overlapping cover leaves are placed on top of the shaft riding leaves which reduces leakage and provides stiffness. The leaves can be straight or angle cut. The shaft riding fingers are designed with mismatched curvature to provide lift off similar to the Rayleigh lift pads in mechanical seals with leading edge clearances nearly twice those of the trailing edge as as shown by Fleming to be optimal for gas flows in convergent seal passages. Leading edge clearances range from 300 to 500 microinches. Balance pockets beneath the leaves provide fluid film feed to the 'Rayleigh lift' surface and the proper balance ratio (mechanical seal) when combined with the static pressure and film pressure. The leaves flex in the radial direction and accommodate thermomechanical behavior as well as axial motion and angular misalignment. In the static mode, there is a net closing force on the leaves. The seals were tested to 70 psi at speeds to 16,000 rpm or surface speeds to 330 fps and temperatures from ambient to 440 F. A slow cycle through the rig critical at 10,000 rpm induced a radial vibration response of 0.004 to 0.005 inch were accommodated by the seal. Preliminary performance data are encouraging demonstrating hydrodynamic liftoff and noncontacting operation at pressure and speeds typical of gas turbine engines. The leakage performance data are significantly better than commercial labyrinth and brush seals which should be expected as this design incorporates the features of the low leakage face or mechanical seal along with the flexibility of the brush configuration.

Self-acting shaft seals

Science.gov (United States)

Ludwig, L. P.

1978-01-01

Self-acting seals are described in detail. The mathematical models for obtaining a seal force balance and the equilibrium operating film thickness are outlined. Particular attention is given to primary ring response (seal vibration) to rotating seat face runout. This response analysis reveals three different vibration models with secondary seal friction being an important parameter. Leakage flow inlet pressure drop and affects of axisymmetric sealing face deformations are discussed. Experimental data on self-acting face seals operating under simulated gas turbine conditions are given. Also a spiral groove seal design operated to 244 m/sec (800 ft/sec) is described.

Seismic considerations in sealing a potential high-level radioactive waste repository

International Nuclear Information System (INIS)

Fernandez, J.A.; Richardson, A.M.; Lin, Ming

1992-01-01

The potential repository system is intended to isolate high-level radioactive waste at Yucca Mountain. One subsystem that may contribute to achieving this objective is the sealing subsystem. This subsystem is comprised of sealing components in the shafts, ramps, underground network of drifts, and the exploratory boreholes. Sealing components can be rigid, as in the case of a shaft seal, or can be more compressible, as in the case of drift fill comprised of mined rockfill. This paper presents the preliminary seismic response of discrete sealing components in welded and nonwelded tuff. Special consideration is given to evaluating the stress in the seal, and the behavior of the interface between the seal and the rock. The seismic responses are computed using both static and dynamic analyses. Also presented is an evaluation of the maximum seismic response encountered by a drift seal with respect to the angle of incidence of the seismic wave. Mitigation strategies and seismic design considerations are proposed which can potentially enhance the overall response of the sealing component and subsequently, the performance of the overall repository system

HMSRP Hawaiian Monk Seal Master Identification Records (seal)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains records of all individually identified Hawaiian monk seals since 1981. These seals were identified by PSD personnel and cooperating scientists...

The development of an auto-sealing system using an electrically shrinkable tube under a low-pressure condition

Energy Technology Data Exchange (ETDEWEB)

Okano, Yoshihiro; Kitagawa, Takao [NKK Corp, Tsu, Mie (Japan); Shoji, Norio [NKK Corp., Yokohama (Japan); Namioka, Toshiyuki [Nippon Kokan Koji Corp., Yokohama (Japan). Research and Development Dept.; Komura, Minoru [Nitto Denko Corp., Fukaya, Saitama (Japan)

1997-04-01

This article describes the development of a system to create high quality, automatic sealing of field joints of polyethylene coated pipelines. The system uses a combination of an electrically heated shrinkable tube and a low-pressure chamber. The self-heating shrinkable tube includes electric heater wires that heat when connected to electricity. A method was developed to eliminate air trapped between the tube and the steel pipe by shrinking the tube under a low-pressure condition. The low-pressure condition was automatic and easily attained by using a vacuum chamber. It was verified that the system produced high quality sealing of the field joints.

Development of a sealed source radiation detector system for gamma ray scanning of petroleum distillation columns

International Nuclear Information System (INIS)

Vasquez Salvador, Pablo Antonio

2004-01-01

Gamma Ray Scanning is an online technique to 'view' the hydraulic performance of an operating column, with no disruption to operating processes conditions (pressure and temperature), as a cost-effective solution. The principle of this methodology consists of a small suitably sealed gamma radiation source and a radiation detector experimentally positioned to the column, moving concurrently in small increments on opposite sides and the quantity of gamma transmitted. The source-detector system consists of: a sealed ''6 0 Co radioactive source in a panoramic lead radiator, a scintillator detector coupled to a ratemeter / analyzer and a mobile system. In this work, a gamma scanning sealed source-detector system for distillation columns, was developed, comparing two scintillator detectors: NaI(Tl) (commercial) and CsI(Tl) (IPEN). In order to project the system, a simulated model of a tray-type distillation column was used. The equipment developed was tested in an industrial column for water treatment (6.5 m diameter and 40 m height). The required activities of 6 ''0Co, laboratory (11.1 MBq) and industrial works (1.48 TBq) were calculated by simulation software. Both, the NaI(Tl) and the CsI(Tl) detectors showed good proprieties for gamma scanning applications, determining the position and presence or absence of trays. (author)

Sealing devices

International Nuclear Information System (INIS)

Coulson, R.A.

1980-01-01

A sealing device for minimising the leakage of toxic or radioactive contaminated environments through a biological shield along an opening through which a flexible component moves that penetrates the shield. The sealing device comprises an outer tubular member which extends over a length not less than the maximum longitudinal movement of the component along the opening. An inner sealing block is located intermediate the length of the component by connectors and is positioned in the bore of the outer tubular member to slide in the bore and effect a seal over the entire longitudinal movement of the component. The cross-section of the device may be circular and the block may be of polytetrafluoroethylene or of nylon impregnated with molybdenum or may be metallic. A number of the sealing devices may be combined into an assembly for a plurality of adjacent longitudinally movable components, each adapted to sustain a tensile load, providing the various drives of a master-slave manipulator. (author)

Electron beam selectively seals porous metal filters

Science.gov (United States)

Snyder, J. A.; Tulisiak, G.

1968-01-01

Electron beam welding selectively seals the outer surfaces of porous metal filters and impedances used in fluid flow systems. The outer surface can be sealed by melting a thin outer layer of the porous material with an electron beam so that the melted material fills all surface pores.

Abrasive wear of intermetallics

International Nuclear Information System (INIS)

Hawk, J.A.; Alman, D.E.; Wilson, R.D.

1995-01-01

The US Bureau of Mines is investigating the wear behavior of a variety of advanced materials. Among the many materials under evaluation are intermetallic alloys based on the compounds: Fe 3 Al, Ti 3 Al, TiAl, Al 3 Ti, NiAl and MoSi 2 . The high hardness, high modulus, low density, and superior environmental stability of these compounds make them attractive for wear materials. This paper reports on the abrasive wear of alloys and composites based on the above compounds. The abrasive wear behavior of these alloys and composites are compared to other engineering materials used in wear applications

Reinforced seal component

International Nuclear Information System (INIS)

Jeanson, G.M.; Odent, R.P.

1980-01-01

The invention concerns a seal component of the kind comprising a soft sheath and a flexible reinforcement housed throughout the entire length of the sheath. The invention enables O ring seals to be made capable of providing a radial seal, that is to say between two sides or flat collars of two cylindrical mechanical parts, or an axial seal, that is to say between two co-axial axisymmetrical areas. The seal so ensured is relative, but it remains adequately sufficient for many uses, for instance, to ensure the separation of two successive fixed blading compartments of axial compressors used in gas diffusion isotope concentration facilities [fr

Reactor vessel sealing plug

International Nuclear Information System (INIS)

Dooley, R.A.

1986-01-01

This invention relates to an apparatus and method for sealing the cold leg nozzles of a nuclear reactor pressure vessel from a remote location during maintenance and inspection of associated steam generators and pumps while the pressure vessel and refueling canal are filled with water. The apparatus includes a sealing plug for mechanically sealing the cold leg nozzle from the inside of a reactor pressure vessel. The sealing plugs include a primary and a secondary O-ring. An installation tool is suspended within the reactor vessel and carries the sealing plug. The tool telescopes to insert the sealing plug within the cold leg nozzle, and to subsequently remove the plug. Hydraulic means are used to activate the sealing plug, and support means serve to suspend the installation tool within the reactor vessel during installation and removal of the sealing plug

Reactor coolant pump seal leakage monitoring

International Nuclear Information System (INIS)

Stevens, D.M.; Spencer, J.W.; Morris, D.J.; James, W.; Shugars, H.G.

1986-01-01

Problems with reactor coolant pump seals have historically accounted for a large percentage of unscheduled outages. Studies performed for the Electric Power Research Institute (EPRI) have shown that the replacement of coolant pump seals has been one of the leading causes of nuclear plant unavailability over the last ten years. Failures of coolant pump seals can lead to primary coolant leakage rates of 200-500 gallons per minute into the reactor building. Airborne activity and high surface contamination levels following these failures require a major cleanup effort and increases the time and personnel exposure required to refurbish the pump seals. One of the problems in assessing seal integrity is the inability to accurately measure seal leakage. Because seal leakage flow is normally very small, it cannot be sensed directly with normal flow instrumentation, but must be inferred from several other temperature and flow measurements. In operating plants the leakage rate has been quantified with a tipping-bucket gauge, a device which indicates when one quart of water has been accumulated. The tipping-bucket gauge has been used for most rainfall-intensity monitoring. The need for a more accurate and less expensive gauge has been addressed. They have developed a drop-counter precipitation sensor has been developed and optimized. The applicability of the drop-counter device to the problem of measuring seal leakage is being investigated. If a review of system specification and known drop-counter performance indicates that this method is feasible for measuring seal leak rates, a drop-counter gauge will be fabricated and tested in the laboratory. If laboratory tests are successful the gauge will be demonstrated in a pump test loop at Ontario Hydro and evaluated under simulated plant conditions. 3 references, 2 figures

Friction and wear behaviour of ion beam modified ceramics

International Nuclear Information System (INIS)

Lankford, J.; Wei, W.; Kossowsky, R.

1987-01-01

In the present study, the sliding friction coefficients and wear rates of carbide, oxide, and nitride materials for potential use as sliding seals (ring/liner) were measured under temparature, environmental, velocity, and loading conditions representative of a diesel engine. In addition, silicon nitride and partially stabilized zirconia discs were modified by ion mixing with TiNi, nickel, cobalt and chromium, and subsequently run against carbide pins, with the objective of producing reduced friction via solid lubrication at elevated temperature. Unmodified ceramic sliding couples were characterized at all temperatures by friction coefficients of 0.24 and above. However, the coefficient at 800 0 C in an oxidizing environment was reduced to below 0.1, for certain material combinations, by the ion implantation of TiNi or cobalt. This beneficial effect was found to derive from lubricious titanium, nickel, and cobalt oxides. (author)

Friction and wear behaviour of ion beam modified ceramics

Science.gov (United States)

Lankford, J.; Wei, W.; Kossowsky, R.

1987-01-01

In the present study, the sliding friction coefficients and wear rates of carbide, oxide, and nitride materials for potential use as sliding seals (ring/liner) were measured under temperature, environmental, velocity, and loading conditions representative of a diesel engine. In addition, silicon nitride and partially stabilized zirconia discs were modified by ion mixing with TiNi, nickel, cobalt and chromium, and subsequently run against carbide pins, with the objective of producing reduced friction via solid lubrication at elevated temperature. Unmodified ceramic sliding couples were characterized at all temperatures by friction coefficients of 0.24 and above. However, the coefficient at 800 C in an oxidizing environment was reduced to below 0.1, for certain material combinations, by the ion implantation of TiNi or cobalt. This beneficial effect was found to derive from lubricious titanium, nickel, and cobalt oxides.

Study of neutron absorbing microspheres in research reactors - Metal systems wear

International Nuclear Information System (INIS)

Gana Watkins, Ignacio A.; Silin, Nicolas; Prado, Miguel O.; Mazufri, Claudio

2012-01-01

Now-a-days, it is increasingly common for nuclear power plants, as well as research reactors, to be designed and built with an alternative safety system aside from control rods. The acids and/or salts in solution injection systems is most frequently used. However, these systems present several implementation and operation problems due to the physical and chemical properties of the used compounds. After analyzing these drawbacks, we developed a new alternative safety system that contains the absorbing element isolated from the aqueous medium. In this context, it's proposed the use of aluminum borosilicate microspheres. The current paper presents erosion wear experiments to determine under which conditions microspheres can be considered as a potential component of a secondary shut down system in a nuclear facility (author))

SSME Seal Test Program: Test results for sawtooth pattern damper seal

Science.gov (United States)

Childs, D. W.

1986-01-01

Direct and transverse force coefficients for 11, sawtooth-pattern, and damper-seal configurations were examined. The designation damper seal uses a deliberately roughened stator and smooth rotor to increase the net damping force developed by a seal. The designation sawtooth-pattern refers to a stator roughness pattern. The sawtooth pattern yields axial grooves in the stator which are interrupted by spacer elements which act as flow constrictions or dams. All seals use the same smooth rotor and have the same, constant, minimum clearance. The stators examined the consequences of changes in the following design parameters: (1) axial-groove depth; (2) number of teeth: (3) number of sawtooth sections; (4) number of spacer elements; (5) dam width; (6) axially aligned sawtooth sections versus axially-staggered sawtooth sections; and (7) groove geometry. It is found that none of the sawtooth-pattern seal performs as well as the best round-hole-pattern seal. Maximum damping configurations for the sawtooth and round-hole-pattern stators have comparable stiffness performance. Several of the sawtooth pattern stators outperformed the best round-hole pattern seal.

Analysis of mechanism of carbide tool wear and control by wear process

Directory of Open Access Journals (Sweden)

Pham Hoang Trung

2017-01-01

Full Text Available The analysis of physic-mechanical and thermal physic properties of hard alloys depending on their chemical composition is conducted. The correlation of cutting properties and regularities of carbide tool wear with cutting conditions and thermal physic properties of tool material are disclosed. Significant influence on the tool wear of not only mechanical, but, in the first place, thermal physic properties of tool and structural materials is established by the researches of Russian scientists, because in the range of industrial used cutting speeds the cause of tool wear are diffusion processes. The directions of intensity decreasing of tool wear by determining rational processing conditions, the choice of tool materials and wear-resistant coating on tool surface are defined.

Circumferential shaft seal

Science.gov (United States)

Ludwig, L. P. (Inventor)

1981-01-01

A circumferential shaft seal comprising two sealing rings held to a rotating shaft by means of a surrounding elastomeric band is disclosed. The rings are segmented and are of a rigid sealing material such as carbon or a polyimide and graphite fiber composite.

Mechanical seal monitoring technique by acoustic emission measurements

Energy Technology Data Exchange (ETDEWEB)

Kataoka, Tadashi; Fujita, Yoshihiro; Kawaguchi, Kazunori; Saito, Kazuhiro; Yokota, Setsuo; Hisada, Yasuhide; Masahiro, Komatsu

1987-09-20

This report describes a technique for mechanical seal monitoring through acoustic emission (AE) measurement. The equipment consists of an AE sensor, preamplifier, multiplexer, main amplifier, effective value transducer and computer system. When the sealed liquid pressure undergoes a large change, the seal surface configuration is monitored and evaluated accurately through AE measurement. If the mechanical seal surface id damaged or worn, the AE level is kept high or continues to fluctuate largely for a rather long period. When leak occurs, the AE value shows great fluctuations either at extremely low levels or at high levels. The former trend is considered to result from a decrease in solid contact due to an excessive amount of liquid film being formed at the seal surface during leak. In the latter case, the leak is attributed to severe damage to the seal surface. (18 figs, 1 tab, 5 photos, 3 refs)

Influence of nitrogen ion implantation on wear studied by a new laboratory wear test

Energy Technology Data Exchange (ETDEWEB)

Szilagyi, E.; Paszti, F.; Vertessy, Z. (Central Research Inst. for Physics, Hungarian Academy of Sciences, Budapest (Hungary))

1991-05-01

A new laboratory wear test is developed in which the wear trace is measured by Rutherford backscattering spectrometry. The advantage of the new test is that the wear rate is directly determinable. The new test setup has been used to study the effects of nitrogen implantation on the wear processes on 115CrV3 steel. The wear rate decreases by a factor of 2 at 4x10{sup 17} N{sup +}/cm{sup 2} implanted dose. (orig.).

Sealing arrangement for radioactive material

International Nuclear Information System (INIS)

Gray, I.L.S.; Sievwright, R.W.T.; Elliott, J.C.

1993-01-01

A sealing arrangement for hermetically sealing two mating surfaces comprises two seals arranged to lie between the surfaces. Each seal provides hermetic sealing over a respective different temperature range and lie serially along the surfaces between the regions to be isolated. A main seal integrity test arrangement is provided in the form of a port and passage. This allows for the introduction of a fluid into or the evacuation of a region between the two seals to detect a leak. The port is also provided with at least two test port seals which seal with a plug. The plug is also provided with a test port to allow the integrity of the test port seal to be tested. (UK)

Impact of Vial Capping on Residual Seal Force and Container Closure Integrity.

Science.gov (United States)

Mathaes, Roman; Mahler, Hanns-Christian; Roggo, Yves; Ovadia, Robert; Lam, Philippe; Stauch, Oliver; Vogt, Martin; Roehl, Holger; Huwyler, Joerg; Mohl, Silke; Streubel, Alexander

2016-01-01

The vial capping process is a critical unit operation during drug product manufacturing, as it could possibly generate cosmetic defects or even affect container closure integrity. Yet there is significant variability in capping equipment and processes, and their relation to potential defects or container closure integrity has not been thoroughly studied. In this study we applied several methods-residual seal force tester, a self-developed system of a piezo force sensor measurement, and computed tomography-to characterize different container closure system combinations that had been sealed using different capping process parameter settings. Additionally, container closure integrity of these samples was measured using helium leakage (physical container closure integrity) and compared to characterization data. The different capping equipment settings lead to residual seal force values from 7 to 115 N. High residual seal force values were achieved with high capping pre-compression force and a short distance between the capping plate and plunge. The choice of container closure system influenced the obtained residual seal force values. The residual seal force tester and piezoelectric measurements showed similar trends. All vials passed physical container closure integrity testing, and no stopper rupture was seen with any of the settings applied, suggesting that container closure integrity was warranted for the studied container closure system with the chosen capping setting ranges. The vial capping process is a critical unit operation during drug product manufacturing, as it could possibly generate cosmetic defects or even affect container closure integrity. Yet there is significant variability in capping equipment and processes, and their relation to potential defects or container closure integrity has not been thoroughly studied. In this study we applied several methods-residual seal force tester, a self-developed system of a piezo force sensor measurement, and

A portable high-power diode laser-based single-stage ceramic tile grout sealing system

Science.gov (United States)

Lawrence, J.; Schmidt, M. J. J.; Li, L.; Edwards, R. E.; Gale, A. W.

2002-02-01

By means of a 60 W high-power diode laser (HPDL) and a specially developed grout material the void between adjoining ceramic tiles has been successfully sealed. A single-stage process has been developed which uses a crushed ceramic tile mix to act as a tough, inexpensive bulk substrate and a glazed enamel surface to provide an impervious surface glaze. The single-stage ceramic tile grout sealing process yielded seals produced in normal atmospheric conditions that displayed no discernible cracks and porosities. The single-stage grout is simple to formulate and easy to apply. Tiles were successfully sealed with power densities as low as 200 kW/ mm2 and at rates of up to 600 mm/ min. Bonding of the enamel to the crushed ceramic tile mix was identified as being primarily due to van der Waals forces and, on a very small scale, some of the crushed ceramic tile mix material dissolving into the glaze. In terms of mechanical, physical and chemical characteristics, the single-stage ceramic tile grout was found to be far superior to the conventional epoxy tile grout and, in many instances, matched and occasionally surpassed that of the ceramic tiles themselves. What is more, the development of a hand-held HPDL beam delivery unit and the related procedures necessary to lead to the commercialisation of the single-stage ceramic tile grout sealing process are presented. Further, an appraisal of the potential hazards associated with the use of the HPDL in an industrial environment and the solutions implemented to ensure that the system complies with the relevant safety standards are given.

Hydrodynamics of a hybrid circulating fluidized bed reactor with a partitioned loop seal system

Energy Technology Data Exchange (ETDEWEB)

Bae, Dal-Hee; Moon, Jong-Ho; Jin, Gyoung Tae; Shun, Dowon [Korea Institute of Energy Research, Daejeon (Korea, Republic of); Yun, Minyoung; Park, Chan Seung; Norbeck, Joseph M. [University of California, Riverside (United States)

2015-07-15

A circulating fluidized bed (CFB) with a hybrid design has been developed and optimized for steam hydrogasification. The hybrid CFB is composed of a bubbling fluidized bed (BFB) type combustor and a fast fluidized bed (FB) type gasifier. Char is burnt in the combustor and the generated heat is supplied to the gasifier along with the bed materials. Two different types of fluidized beds are connected to each other with a newly developed partitioned loop seal to avoid direct contact between two separate gas streams flowing in each fluidized bed. Gas mixing tests were carried out with Air and Argon in a cold model hybrid CFB to test the loop seal efficiency. Increase in solid inventory in the loop seal can improve the gas separation efficiency. It can be realized at higher gas velocity in fast bed and with higher solid inventory in the loop seal system. In addition, bed hydrodynamics was investigated with varying gas flow conditions and particle sizes in order to obtain a full understanding of changes of solid holdup in the FB. The solid holdup in the FB increased with increasing gas velocity in the BFB. Conversely, increase in gas velocity in the FB contributed to reducing the solid holdup in the FB. It was observed that changing the particle size of bed material does not have a big impact on hydrodynamic parameters.

Hydrodynamics of a hybrid circulating fluidized bed reactor with a partitioned loop seal system

International Nuclear Information System (INIS)

Bae, Dal-Hee; Moon, Jong-Ho; Jin, Gyoung Tae; Shun, Dowon; Yun, Minyoung; Park, Chan Seung; Norbeck, Joseph M.

2015-01-01

A circulating fluidized bed (CFB) with a hybrid design has been developed and optimized for steam hydrogasification. The hybrid CFB is composed of a bubbling fluidized bed (BFB) type combustor and a fast fluidized bed (FB) type gasifier. Char is burnt in the combustor and the generated heat is supplied to the gasifier along with the bed materials. Two different types of fluidized beds are connected to each other with a newly developed partitioned loop seal to avoid direct contact between two separate gas streams flowing in each fluidized bed. Gas mixing tests were carried out with Air and Argon in a cold model hybrid CFB to test the loop seal efficiency. Increase in solid inventory in the loop seal can improve the gas separation efficiency. It can be realized at higher gas velocity in fast bed and with higher solid inventory in the loop seal system. In addition, bed hydrodynamics was investigated with varying gas flow conditions and particle sizes in order to obtain a full understanding of changes of solid holdup in the FB. The solid holdup in the FB increased with increasing gas velocity in the BFB. Conversely, increase in gas velocity in the FB contributed to reducing the solid holdup in the FB. It was observed that changing the particle size of bed material does not have a big impact on hydrodynamic parameters

Seismic considerations in sealing a potential high-level radioactive waste repository

International Nuclear Information System (INIS)

Fernandez, J.A.; Richardson, A.M.; Lin, Ming

1993-01-01

The potential repository system is intended to isolate high-level radioactive waste at Yucca Mountain according the performance objective--10 CFR 60.112. One subsystem that may contribute to achieving this objective is the sealing subsystem. This subsystem is comprised of sealing components in the shafts, ramps, underground network of drifts, and the exploratory boreholes. Sealing components can be rigid, as in the case of a shaft seal, or can be more compressible, as in the case of drift fill comprised of mined rockfill. This paper presents the preliminary seismic response of discrete sealing components in welded and nonwelded tuff. Special consideration is given to evaluating the stress in the seal, and the behavior of the interface between the seal and the rock. The seismic responses are computed using both static and dynamic analyses. Also presented is an evaluation of the maximum seismic response encountered by a drift seal with respect to the angle of incidence of the seismic wave. Mitigation strategies and seismic design considerations are proposed which can potentially enhance the overall response of the sealing component and subsequently, the performance of the overall repository system

Contributions to the sealing of landfills. Possibilities for controlling landfill sealing systems. Interactions of cationic tensides with clay minerals and their relevance for the long-term stability of landfill base sealings. Beitraege zur Abdichtung von Deponien. Moeglichkeiten zur Kontrollierbarkeit von Deponieabdichtungssystemen. Die Wechselwirkungen kationischer Tenside mit Tonmineralen und ihre Relevanz fuer die Langzeitstabilitaet von Deponiebasisabdichtungen

Energy Technology Data Exchange (ETDEWEB)

Schlagintweit, F

1992-01-01

The tightness of landfills is generally controllable via ground water level indicators, by observation of surface and base scalings, and by an appropriate device placed between the base sealing and the technical or geological barrier. Lately, also the use of sensor systems is being considered for this purpose. But especially as regards the base sealing, it is imperative that the control device should not lead to impaired function of the sealing layer above the control drainage. Controllable base sealings do not eliminate the need for monitoring possible pollutant propagation via ground water level indicators. (orig.)

Design and operation problems related to water curtain system for underground water-sealed oil storage caverns

Directory of Open Access Journals (Sweden)

Zhongkui Li

2016-10-01

Full Text Available The underground water-sealed storage technique is critically important and generally accepted for the national energy strategy in China. Although several small underground water-sealed oil storage caverns have been built in China since the 1970s, there is still a lack of experience for large-volume underground storage in complicated geological conditions. The current design concept of water curtain system and the technical instruction for system operation have limitations in maintaining the stability of surrounding rock mass during the construction of the main storage caverns, as well as the long-term stability. Although several large-scale underground oil storage projects are under construction at present in China, the design concepts and construction methods, especially for the water curtain system, are mainly based on the ideal porosity medium flow theory and the experiences gained from the similar projects overseas. The storage projects currently constructed in China have the specific features such as huge scale, large depth, multiple-level arrangement, high seepage pressure, complicated geological conditions, and high in situ stresses, which are the challenging issues for the stability of the storage caverns. Based on years' experiences obtained from the first large-scale (millions of cubic meters underground water-sealed oil storage project in China, some design and operation problems related to water curtain system during project construction are discussed. The drawbacks and merits of the water curtain system are also presented. As an example, the conventional concept of “filling joints with water” is widely used in many cases, as a basic concept for the design of the water curtain system, but it is immature. In this paper, the advantages and disadvantages of the conventional concept are pointed out, with respect to the long-term stability as well as the safety of construction of storage caverns. Finally, new concepts and principles

Investigation on hard coating of pivot-jewel bearing and wearing performance

International Nuclear Information System (INIS)

Han Kun; Dai Xingjian

2014-01-01

The reliability of high speed rotating machine is related to the anti-wear properties of pivot jewel bearing used in the system. To reduce its wearing process, hard coating method is used on the steel pivot. Through the wearing test on specialized facilities, its founded that the TiN coating shows better performance than DLC coating, and multi-layer TiN coating can slow down the pivot's wearing process obviously compared to other methods. (authors)

Effect of bar sealing parameters on OPP/MCPP heat seal strength

Directory of Open Access Journals (Sweden)

2007-11-01

Full Text Available The effect of bar sealing parameters on the heat seal strength of oriented polypropylene (OPP/metallic cast polypropylene (MCPP laminate film was investigated. Based on the results obtained from the parametric study, a bar sealing process window was developed. All points drop within the process window are combinations of platen temperature and dwell time that produce acceptable heat seal. Optimum combinations are indicated by the lower border of the window. The plateau initiation temperature, Tpi of OPP/MCPP laminate film used in the present study occurred before the final melting temperature, Tmf of the sealant material. The highest achievable heat seal strength was at the plateau region, and the corresponding failure modes were delaminating, tearing or combine failure modes (delaminating and tearing. Minimum pressure level of 1.25 bars is necessary to bring the laminate interface into intimate contact in order to effect sealing.

Tooth wear

Directory of Open Access Journals (Sweden)

Tušek Ivan

2014-01-01

Full Text Available Tooth wear is the loss of dental hard tissue that was not caused by decay and represents a common clinical problem of modern man. In the etiology of dental hard tissue lesions there are three dominant mechanisms that may act synergistically or separately:friction (friction, which is caused by abrasion of exogenous, or attrition of endogenous origin, chemical dissolution of dental hard tissues caused by erosion, occlusal stress created by compression and flexion and tension that leads to tooth abfraction and microfracture. Wear of tooth surfaces due to the presence of microscopic imperfections of tooth surfaces is clinically manifested as sanding veneers. Tribology, as an interdisciplinary study of the mechanisms of friction, wear and lubrication at the ultrastructural level, has defined a universal model according to which the etiopathogenesis of tooth wear is caused by the following factors: health and diseases of the digestive tract, oral hygiene, eating habits, poor oral habits, bruxism, temporomandibular disorders and iatrogenic factors. Attrition and dental erosion are much more common in children with special needs (Down syndrome. Erosion of teeth usually results from diseases of the digestive tract that lead to gastroesophageal reflux (GER of gastric juice (HCl. There are two basic approaches to the assessment of the degree of wear and dental erosion. Depending on the type of wear (erosion, attrition, abfraction, the amount of calcium that was realised during the erosive attack could be determined qualitatively and quantitatively, or changes in optical properties and hardness of enamel could be recorded, too. Abrasion of teeth (abrasio dentium is the loss of dental hard tissue caused by friction between the teeth and exogenous foreign substance. It is most commonly provoked by prosthetic dentures and bad habits, while its effect depends on the size of abrasive particles and their amount, abrasive particle hardness and hardness of tooth

Comparative study on two different seal surface structure for reactor pressure vessel sealing behavior

International Nuclear Information System (INIS)

Chen Jun; Xiong Guangming; Deng Xiaoyun

2014-01-01

The seal surface structure is very important to reactor pressure vessel (RPV) sealing behavior. In this paper, two 3-D RPV sealing analysis finite models have been established with different seal surface structures, in order to study the influence of two structures. The separation of RPV upper and lower flanges, bolt loads and etc. are obtained, which are used to evaluate the sealing behavior of the RPV. Meanwhile, the comparative analysis of safety margin of two seal surface structural had been done, which provides the theoretical basis for RPV seal structure design optimization. (authors)

Design of Active Magnetic Bearing Controllers for Rotors Subjected to Gas Seal Forces

DEFF Research Database (Denmark)

Lauridsen, Jonas Skjødt; Santos, Ilmar F.

2018-01-01

Proper design of feedback controllers is crucial for ensuring high performance of Active Magnetic Bearing (AMB) supported rotor dynamic systems. Annular seals in those systems can contribute with significant forces, which, in many cases, are hard to model in advance due to complex geometries...... of the seal and multiphase fluids. Hence, it can be challenging to design AMB controllers that will guarantee robust performance for these kinds of systems. This paper demonstrates the design, simulation and experimental results of model based controllers for AMB systems, subjected to dynamic seal forces....... The controllers are found using H-infinity - and µ synthesis and are based on a global rotor dynamic model in-which the seal coefficients are identified in-situ. The controllers are implemented in a rotor-dynamic test facility with two radial AMBs and one annular seal with an adjustable inlet pressure. The seal...

Seals in motion

NARCIS (Netherlands)

Brasseur, Sophie Marie Jacqueline Michelle

2017-01-01

The harbour seal Phoca vitulina and the grey seal Halichoerus grypus have been inhabitants of the Wadden Sea since millennia. Prehistoric findings indicate the presence of both species around 5000 BC. This changed dramatically in the mid Middle-Ages as around 1500 AC, the grey seal disappeared from

Geochemical analysis of the sealing system. Technical Report to work package 9.1.2. Preliminary safety case of the Gorleben site (VSG)

Energy Technology Data Exchange (ETDEWEB)

Xie, Mingliang; Herbert, Horst-Juergen

2012-02-15

The geochemical reaction simulation of ground water and brines with sealing materials for a proposed repository at the Gorleben site is a task under the framework of the VSG project. The calculations presented in this report are aimed to provide a preliminary evaluation of the geochemical stability of three potential engineering barrier materials foreseen in the shaft sealing system in case of groundwater and brine intrusion. The long-term stability of these materials is a key issue for the sealing function of the shaft seals. This is governed by many factors such as geotechnical, hydraulic and geochemical processes. In order to better understand the potential effect of geochemical processes on the long-term properties of these sealing materials, geochemical simulations of the potential interactions between groundwater and brine and shaft sealing materials were performed.

Potential countersample materials for in vitro simulation wear testing.

Science.gov (United States)

Shortall, Adrian C; Hu, Xiao Q; Marquis, Peter M

2002-05-01

Any laboratory investigation of the wear resistance of dental materials needs to consider oral conditions so that in vitro wear results can be correlated with in vivo findings. The choice of the countersample is a critical factor in establishing the pattern of tribological wear and in achieving an efficient in vitro wear testing system. This research investigated the wear behavior and surface characteristics associated with three candidate countersample materials used for in vitro wear testing in order to identify a possible suitable substitute for human dental enamel. Three candidate materials, stainless steel, steatite and dental porcelain were evaluated and compared to human enamel. A variety of factors including hardness, wear surface evolution and frictional coefficients were considered, relative to the tribology of the in vivo situation. The results suggested that the dental porcelain investigated bore the closest similarity to human enamel of the materials investigated. Assessment of potential countersample materials should be based on the essential tribological simulation supported by investigations of mechanical, chemical and structural properties. The selected dental porcelain had the best simulating ability among the three selected countersample materials and this class of material may be considered as a possible countersample material for in vitro wear test purposes. Further studies are required, employing a wider range of dental ceramics, in order to optimise the choice of countersample material for standardized in vitro wear testing.

Contact Thermal Analysis and Wear Simulation of a Brake Block

Directory of Open Access Journals (Sweden)

Nándor Békési

2013-01-01

Full Text Available The present paper describes an experimental test and a coupled contact-thermal-wear analysis of a railway wheel/brake block system through the braking process. During the test, the friction, the generated heat, and the wear were evaluated. It was found that the contact between the brake block and the wheel occurs in relatively small and slowly moving hot spots, caused by the wear and the thermal effects. A coupled simulation method was developed including numerical frictional contact, transient thermal and incremental wear calculations. In the 3D simulation, the effects of the friction, the thermal expansion, the wear, and the temperature-dependent material properties were also considered. A good agreement was found between the results of the test and the calculations, both for the thermal and wear results. The proposed method is suitable for modelling the slowly oscillating wear caused by the thermal expansions in the contact area.

Effect of tooth profile modification on wear in internal gears

Science.gov (United States)

Tunalioglu, M. S.; Tuc, B.

2018-05-01

Internal gears are often used in the automotive industry when two gears are required to rotate in the same direction. Tooth shapes, slippage speeds at the beginning and end of meshing are different according to the external gears. Manufacturing of internal gears is more difficult than external gears. Thus, it is necessary to determine the working conditions and wear behavior of internal gears carefully. The profile modification method in terms of strength and surface tension of the gear mechanism are performed in order to increase the load-carrying capability. In this study, profile modification method was performed in the internal gears to reduce the wear on the teeth. For this purpose, the wear of the internal gears was theoretically investigated by adapting the Archard wear equation to the internal gears. Closed circuit power circulation system was designed and manufactured to experimentally investigate the wear in internal gears. With this system, wear tests of gears made of St 50 material without profile modification and different profile modifications were made and the results were compared. Experimental study was performed in the same loading and cycle time conditions to validate the theoretical results and it was seen that the results are compatible. According to the experimental results, it is seen that in the internal gears, when profile modification done the wear is decreased in the teeth tip region.

Steam generator fretting-wear damage: A summary of recent findings

International Nuclear Information System (INIS)

Guerout, F.M.; Fisher, N.J.

1999-01-01

Flow-induced vibration of steam generator (SG) tubes may sometimes result in fretting-wear damage at the tube-to-support locations. Fretting-wear damage predictions are largely based on experimental data obtained at representative test conditions. Fretting-wear of SG materials has been studied at the Chalk River Laboratories for two decades. Tests are conducted in fretting-wear test machines that simulate SG environmental conditions and tube-to-support dynamic interactions. A new high-temperature force and displacement measuring system was developed to monitor tube-to-support interaction (i.e., work-rate) at operating conditions. This improvement in experimental fretting-wear technology was used to perform a comprehensive study of the effect of various environment and design parameters on SG tube wear damage. This paper summarizes the results of tests performed over the past 4 yr to study the effect of temperature, water chemistry, support geometry, and tube material on fretting-wear. The results show a significant effect of temperature on tube wear damage. Therefore, fretting-wear tests must be performed at operating temperatures in order to be relevant. No significant effect of the type of water treatment on tube wear damage was observed. For predominantly impacting motion, the wear of SG tubes in contact with 410 stainless steel is similar regardless of whether Alloy 690 or Alloy 800 is used as tubing material or whether lattice bars or broached hole supports are used. Based on results presented in this paper, an average wear coefficient value is recommended that is used for the prediction of SG tube wear depth versus time

Accessory components in gas-lubricated floating ring seals; Zusatzeinrichtungen an gasgeschmierten Gleitringdichtungen

Energy Technology Data Exchange (ETDEWEB)

Kirchner, C.; Victor, K.H.

1995-12-31

The present paper uses existing designs of floating-ring seal systems to illustrate their use as accessory components in gas-lubricated axial-face seals. These floating-ring seals may be used as pre-seals on the side of the axial-face seal facing the product. Here they are subject to high ambient pressure and small pressure differences. On the side of the axial-face seal facing the sliding bearing they are used as post-seals, where they are subject to atmospheric conditions and small pressure differences. The authors present various purpose-specific designs of these seal systems. Theoretical calculation models are compared with measuring results obtained under conditions close to actual practice. (orig.) [Deutsch] Anhand von ausgefuehrten Konstruktionen werden Schwimmring-Dichtungssysteme als Zusatzeinrichtung an gasgeschmierten Gleitringdichtungen (GLRD) erlaeutert. Auf der produktzugewandten Seite der GLRD werden diese Schwimmringdichtungen als Vordichtung (Pre-Seal) eingesetzt, die bei hohen Umgebungsdruecken und geringen Druckdifferenzen betrieben werden. Auf der dem Gleitlager zugewandten Seite der GLRD werden Schwimmringdichtungen bei atmosphaerischen Bedingungen und ebenfalls geringen Druckdifferenzen als nachgeschaltete Dichtung (Post-Seal) eingesetzt. Es werden konstruktive Loesungen fuer die verschiedenen Aufgaben dieser Dichtungssysteme vorgestellt. Theoretische Berechnungsmodelle werden mit praxisnahen Messergebnissen verglichen. (orig.)

Cover gas seals. 11 - FFTF-LMFBR seal-test program, January-March 1974

International Nuclear Information System (INIS)

Kurzeka, W.; Oliva, R.; Welch, F.

1974-01-01

The objectives of this program are to: (1) conduct static and dynamic tests to demonstrate or determine the mechanical performance of full-size (cross section) FFTF fuel transfer machine and reactor vessel head seals intended for use in a sodium vapor - inert gas environment, (2) demonstrate that these FFTF seals or new seal configuration provide acceptable fission product and cover gas retention capabilities at LMFBR Clinch River Plant operating environmental conditions other than radiation, and (3) develop improved seals and seal technology for the LMFBR Clinch River Plant to support the national objective to reduce all atmospheric contaminations to low levels

Bentonite as a waste isolation pilot plant shaft sealing material

International Nuclear Information System (INIS)

Daemen, J.; Ran, Chongwei

1996-12-01

Current designs of the shaft sealing system for the Waste Isolation Pilot Plant (WIPP) propose using bentonite as a primary sealing component. The shaft sealing designs anticipate that compacted bentonite sealing components can perform through the 10,000-year regulatory period and beyond. To evaluate the acceptability of bentonite as a sealing material for the WIPP, this report identifies references that deal with the properties and characteristics of bentonite that may affect its behavior in the WIPP environment. This report reviews published studies that discuss using bentonite as sealing material for nuclear waste disposal, environmental restoration, toxic and chemical waste disposal, landfill liners, and applications in the petroleum industry. This report identifies the physical and chemical properties, stability and seal construction technologies of bentonite seals in shafts, especially in a saline brine environment. This report focuses on permeability, swelling pressure, strength, stiffness, longevity, and densification properties of bentonites

Bentonite as a waste isolation pilot plant shaft sealing material

Energy Technology Data Exchange (ETDEWEB)

Daemen, J.; Ran, Chongwei [Univ. of Nevada, Reno, NV (United States)

1996-12-01

Current designs of the shaft sealing system for the Waste Isolation Pilot Plant (WIPP) propose using bentonite as a primary sealing component. The shaft sealing designs anticipate that compacted bentonite sealing components can perform through the 10,000-year regulatory period and beyond. To evaluate the acceptability of bentonite as a sealing material for the WIPP, this report identifies references that deal with the properties and characteristics of bentonite that may affect its behavior in the WIPP environment. This report reviews published studies that discuss using bentonite as sealing material for nuclear waste disposal, environmental restoration, toxic and chemical waste disposal, landfill liners, and applications in the petroleum industry. This report identifies the physical and chemical properties, stability and seal construction technologies of bentonite seals in shafts, especially in a saline brine environment. This report focuses on permeability, swelling pressure, strength, stiffness, longevity, and densification properties of bentonites.

Geotribology - Friction, wear, and lubrication of faults

Science.gov (United States)

Boneh, Yuval; Reches, Ze'ev

2018-05-01

We introduce here the concept of Geotribology as an approach to study friction, wear, and lubrication of geological systems. Methods of geotribology are applied here to characterize the friction and wear associated with slip along experimental faults composed of brittle rocks. The wear in these faults is dominated by brittle fracturing, plucking, scratching and fragmentation at asperities of all scales, including 'effective asperities' that develop and evolve during the slip. We derived a theoretical model for the rate of wear based on the observation that the dynamic strength of brittle materials is proportional to the product of load stress and loading period. In a slipping fault, the loading period of an asperity is inversely proportional to the slip velocity, and our derivations indicate that the wear-rate is proportional to the ratio of [shear-stress/slip-velocity]. By incorporating the rock hardness data into the model, we demonstrate that a single, universal function fits wear data of hundreds of experiments with granitic, carbonate and sandstone faults. In the next step, we demonstrate that the dynamic frictional strength of experimental faults is well explained in terms of the tribological parameter PV factor (= normal-stress · slip-velocity). This factor successfully delineates weakening and strengthening regimes of carbonate and granitic faults. Finally, our analysis revealed a puzzling observation that wear-rate and frictional strength have strikingly different dependencies on the loading conditions of normal-stress and slip-velocity; we discuss sources for this difference. We found that utilization of tribological tools in fault slip analyses leads to effective and insightful results.

Seals Research at AlliedSignal

Science.gov (United States)

Ullah, M. Rifat

1996-01-01

A consortium has been formed to address seal problems in the Aerospace sector of Allied Signal, Inc. The consortium is represented by makers of Propulsion Engines, Auxiliary Power Units, Gas Turbine Starters, etc. The goal is to improve Face Seal reliability, since Face Seals have become reliability drivers in many of our product lines. Several research programs are being implemented simultaneously this year. They include: Face Seal Modeling and Analysis Methodology; Oil Cooling of Seals; Seal Tracking Dynamics; Coking Formation & Prevention; and Seal Reliability Methods.

Seals

International Nuclear Information System (INIS)

Welsher, R.A.G.

1982-01-01

An aperture through a biological shield is sealed by a flexible sheath having a beading at one end located on an annular member slidable in the aperture such that the beading bears in sealing engagement against the sides of the aperture. The annular member is retained by a retractable latch and can be rejected by pushing it out of the aperture using a replacement annular member with a replacement sheath thereon to butt against the annular member to be rejected. The replacement annular member may be mounted on a tubular device having an outer co-axial member for operating the latch when the replacement annular member butts against the annular member to be rejected. Applications include effecting a seal between a remote handling equipment and a wall through which the equipment extends. (author)

Improved operation in CANDU plants with CAN8 PHT pump seals

International Nuclear Information System (INIS)

Graham, T.; McInnes, D.; Rhodes, D.

1997-01-01

The CAN8 PHT pump seal is currently operating in twenty-one pumps, twelve at Bruce A, seven at Bruce B and in both pumps at Grand Gulf Nuclear Station (GGNS). The CAN8 seal has markedly improved performance over the CAN2 seal previously used at the Bruce stations and the SU seals previously used at GGNS. Details of the performance improvements are discussed. Prior to installation in Bruce B, the CAN8 seal was slightly modified and then demonstrated to be resistant to reverse pressurization failures, since this was a known failure mechanism with the CAN2 seal. Subsequent experience showed that Bruce A was also susceptible to reverse pressure incidents. A review of plant operating procedures at Bruce A showed reverse pressure was likely the initiating factor for several previously unexplained seal disturbances. The reverse pressure failure mechanism is described, as are the improved system operating procedures designed to prevent it. Preventative procedures have now been implemented across Ontario Hydro Nuclear. The ability to track down seal failure mechanisms such as this is greatly enhanced by the improved system monitoring and data retrieval now in place at Bruce A and Bruce B. (author)

Electronic seal

International Nuclear Information System (INIS)

Musyck, E.

1981-01-01

An electronic seal is presented for a volume such as container for fissile materials. The seal encloses a lock for barring the space as well as a device for the detection and the recording of the intervention of the lock. (AF)

Infection studies in mink with seal-derived morbillivirus

DEFF Research Database (Denmark)

Blixenkrone-Møller, M; Svansson, V; Have, P.

1989-01-01

Morbillivirus derived from diseased harbour seals (Phoca vitulina) has characteristics of acute virulent canine distemper virus infection in mink. The infection induced a disease resembling the acute systemic and nervous form of canine distemper.......Morbillivirus derived from diseased harbour seals (Phoca vitulina) has characteristics of acute virulent canine distemper virus infection in mink. The infection induced a disease resembling the acute systemic and nervous form of canine distemper....

Multiscale Modeling of Wear Degradation in Cylinder Liners

KAUST Repository

Moraes, Alvaro

2014-03-20

Every mechanical system is naturally subjected to some kind of wear process that, at some point, will cause failure in the system if no monitoring or treatment process is applied. Since failures often lead to high economical costs, it is essential both to predict and to avoid them. To achieve this, a monitoring system of the wear level should be implemented to decrease the risk of failure. In this work, we take a first step into the development of a multiscale indirect inference methodology for state-dependent Markovian pure jump processes. This allows us to model the evolution of the wear level and to identify when the system reaches some critical level that triggers a maintenance response. Since the likelihood function of a discretely observed pure jump process does not have an expression that is simple enough for standard nonsampling optimization methods, we approximate this likelihood by expressions from upscaled models of the data. We use the Master Equation (ME) to assess the goodness-of-fit and to compute the distribution of the hitting time to the critical level.

Effect of the blades and seals system wear on steam turbine efficiency and power; Efecto del desgaste del sistema de alabes y sellos sobre la eficiencia y potencia de las turbinas de vapor

Energy Technology Data Exchange (ETDEWEB)

Campos Amezcua, Alfonso; Kubiak Szyszka, Janusz [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1997-12-31

The implementation of a method for steam turbine evaluation through the measured geometry in the flow channel and its operating conditions, is presented. This method, previously developed, allows the identification and quantification of the power and efficiency loss due to the wear of its elements (worn or bent blades, worn seals, deposits, etc.); the benefit that is obtained is a more precise knowledge on the turbine behavior and a basis is acquired to give priority to the maintenance work, from the stand point of energy utilization. In this paper, the power and efficiency loss of a 300 MW steam turbine is located and evaluated, a sensibility analysis is presented for the typical elements that cause the deterioration of the efficiency in this type of turbines. [Espanol] Se presenta la implementacion de un metodo de evaluacion de turbinas de vapor a partir de la geometria medida del canal de flujo y sus condiciones de operacion. Este metodo, previamente desarrollado, permite identificar y cuantificar las perdidas de potencia y eficiencia debido al desgaste de sus elementos (alabes desgastados o doblados, sellos desgastados, depositos, etcetera); el beneficio que se obtiene es un conocimiento mas preciso del comportamiento de la turbina y que se tiene una base para dar prioridad a los trabajos de mantenimiento desde el punto de vista de aprovechamiento de la energia. En este articulo se localizan y evaluan las perdidas de potencia y eficiencia de una turbina de vapor de 300 MW, ademas, se presenta un analisis de sensibilidad para los elementos tipicos que originan el deterioro de la eficiencia en este tipo de turbinas.

Effect of the blades and seals system wear on steam turbine efficiency and power; Efecto del desgaste del sistema de alabes y sellos sobre la eficiencia y potencia de las turbinas de vapor

Energy Technology Data Exchange (ETDEWEB)

Campos Amezcua, Alfonso; Kubiak Szyszka, Janusz [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1998-12-31

The implementation of a method for steam turbine evaluation through the measured geometry in the flow channel and its operating conditions, is presented. This method, previously developed, allows the identification and quantification of the power and efficiency loss due to the wear of its elements (worn or bent blades, worn seals, deposits, etc.); the benefit that is obtained is a more precise knowledge on the turbine behavior and a basis is acquired to give priority to the maintenance work, from the stand point of energy utilization. In this paper, the power and efficiency loss of a 300 MW steam turbine is located and evaluated, a sensibility analysis is presented for the typical elements that cause the deterioration of the efficiency in this type of turbines. [Espanol] Se presenta la implementacion de un metodo de evaluacion de turbinas de vapor a partir de la geometria medida del canal de flujo y sus condiciones de operacion. Este metodo, previamente desarrollado, permite identificar y cuantificar las perdidas de potencia y eficiencia debido al desgaste de sus elementos (alabes desgastados o doblados, sellos desgastados, depositos, etcetera); el beneficio que se obtiene es un conocimiento mas preciso del comportamiento de la turbina y que se tiene una base para dar prioridad a los trabajos de mantenimiento desde el punto de vista de aprovechamiento de la energia. En este articulo se localizan y evaluan las perdidas de potencia y eficiencia de una turbina de vapor de 300 MW, ademas, se presenta un analisis de sensibilidad para los elementos tipicos que originan el deterioro de la eficiencia en este tipo de turbinas.

Wear and breakage monitoring of cutting tools by an optical method: theory

Science.gov (United States)

Li, Jianfeng; Zhang, Yongqing; Chen, Fangrong; Tian, Zhiren; Wang, Yao

1996-10-01

An essential part of a machining system in the unmanned flexible manufacturing system, is the ability to automatically change out tools that are worn or damaged. An optoelectronic method for in situ monitoring of the flank wear and breakage of cutting tools is presented. A flank wear estimation system is implemented in a laboratory environment, and its performance is evaluated through turning experiments. The flank wear model parameters that need to be known a priori are determined through several preliminary experiments, or from data available in the literature. The resulting cutting conditions are typical of those used in finishing cutting operations. Through time and amplitude domain analysis of the cutting tool wear states and breakage states, it is found that the original signal digital specificity (sigma) 2x and the self correlation coefficient (rho) (m) can reflect the change regularity of the cutting tool wear and break are determined, but which is not enough due to the complexity of the wear and break procedure of cutting tools. Time series analysis and frequency spectrum analysis will be carried out, which will be described in the later papers.

Wear studies of engine components using neutron activation techniques

International Nuclear Information System (INIS)

Banados Perez, H.E.; Carvalho, G.; Daltro, T.F.L.

1984-01-01

The results obtained in a series of tests for determining the wearing rate of some diesel engine components are reported. The pieces investigated were the needles of fuel injection nozzles, that were previously irradiated with a 10 13 nv in the IEA-R1 nuclear reactor, and the wearing rate was established for different types of fuels. Total wear was calculated by measuring the specific activity of 51 Cr present in the fuel and originated by metal particles worn from the needle. Wear were performed using a device that simulated the actual working conditions of the injection nozzles. The system was run during 350 hours and, along that period, 36 fuel samples of 10 ml each, were collected and analysed for cumulative wear calculation. A metal concentration as low as 10- 6 g in 10 ml of fuel sample could be measured by this method. At present time this procedure is being applied for measuring the wear-rate of other nozzle parts, using localized neutron activation techiques. (Author) [pt

Development of Induction Brazing System for Sealing Instrumentation Feed through Part of Nuclear Fuel Test Rig

Energy Technology Data Exchange (ETDEWEB)

Hong, Jintae; Kim, Kahye; Heo, Sungho; Ahn, Sungho; Joung, Changyoung; Son, Kwangjae; Jung, Yangil [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2013-12-15

To test the performance of nuclear fuels, coolant needs to be circulated through the test rig installed in the test loop. Because the pressure and temperature of the coolant is 15.5 MPa and 300 .deg. C respectively, coolant sealing is one of the most important processes in fabricating a nuclear fuel test rig. In particular, 15 instrumentation cables installed in a test rig pass through the pressure boundary, and brazing is generally applied as a sealing method. In this study, an induction brazing system has been developed using a high frequency induction heater including a vacuum chamber. For application in the nuclear field, BNi2 should be used as a paste, and optimal process variables for Ni brazing have been found by several case studies. The performance and soundness of the brazed components has been verified by a tensile test, cross section test, and sealing performance test.

Wear-Out Sensitivity Analysis Project Abstract

Science.gov (United States)

Harris, Adam

2015-01-01

During the course of the Summer 2015 internship session, I worked in the Reliability and Maintainability group of the ISS Safety and Mission Assurance department. My project was a statistical analysis of how sensitive ORU's (Orbital Replacement Units) are to a reliability parameter called the wear-out characteristic. The intended goal of this was to determine a worst case scenario of how many spares would be needed if multiple systems started exhibiting wear-out characteristics simultaneously. The goal was also to determine which parts would be most likely to do so. In order to do this, my duties were to take historical data of operational times and failure times of these ORU's and use them to build predictive models of failure using probability distribution functions, mainly the Weibull distribution. Then, I ran Monte Carlo Simulations to see how an entire population of these components would perform. From here, my final duty was to vary the wear-out characteristic from the intrinsic value, to extremely high wear-out values and determine how much the probability of sufficiency of the population would shift. This was done for around 30 different ORU populations on board the ISS.

Strength and gas-abrasive wear-resistance of zirconium carbide based cerments

International Nuclear Information System (INIS)

Samsonov, G.V.; Dan'kin, A.A.; Markov, A.A.; Bogomol, I.V.

1976-01-01

Results relating to a study of cermet strength and wear resistance by means of a gas-abrasive flow are presented. It has been found that with a higher amount of the metallic binder (over 25 at.%) in zirconium carbide-based cermets the bending and compression strength and also hardness and wear resistance within the systems ZrC-Nb, ZrC-Mo, ZrC-W become lower. The interrelation of the cermet wear resistance of the various systems and their bending and compression strengths, which, in turn, depend on the electronic structure is shown

PREPP [Process Experimental Pilot Plant] rotary kiln seals: Problem and resolution

International Nuclear Information System (INIS)

Drexler, R.L.

1990-01-01

The Process Experimental Pilot Plant (PREPP) is a facility designed to demonstrate processing of low level chemical and transuranic hazardous waste. The plant includes equipment for handling the incoming waste containers, shredding, incineration and cooling the waste, grouting the residue and scrubbing and filtration of the off gas. The process incinerator is a rotary kiln approximately 8-1/2 ft diameter and 25 ft long with a rotary seal assembly at each end. Each seal assembly consists of a primary, secondary and tertiary seal, with a positive air pressure between primary and secondary seals to prevent out-leakage from the kiln. The kiln operates at 0.5 inch water negative pressure. From the very outset the kiln seals exhibited excessive drag which taxed the kiln drive capacity and excessive in-leakage which limited kiln temperature. An engineering evaluation concluded that the original seals supplied by the kiln vendor could not accommodate expansion and centerline shift of the kiln resulting from heatup of the kiln and its support system. A totally new concept kiln seal design has been generated to replace the (modified) original seals. This new seal system has been designed to provide a very tight long lasting seal which will accommodate the 1.5 inch axial shift and up to 1 inch radial movement of the kiln shell. Design lifetime of the seal is 10,000 operating hours between major maintenance services while maintaining an acceptable leak rate hot or cold, rotating or stopped. The design appears adaptable to any size kiln and is suitable for retrofit to existing kilns. A one-third scale prototype seal assembly is being built to verify the concept prior to construction of the 10 ft diameter seals for the PREPP rotary kiln. 4 figs

Sliding Wear and Fretting Wear of DLC-Based, Functionally Graded Nanocomposite Coatings

Science.gov (United States)

Miyoshi, K.; Pohlchuck, B.; Street, Kenneth W.; Zabinski, J. S.; Sanders, J. H.; Voevodin, A. a.; Wu, R. L. C.

1999-01-01

Improving the tribological functionality of diamondlike carbon (DLC) films--developing, good wear resistance, low friction, and high load-carrying capacity-was the aim of this investigation. Nanocomposite coatings consisting of an amorphous DLC (a-DLC) top layer and a functionally graded titanium-titanium carbon-diamondlike carbon (Ti-Ti(sub x) C(sub y)-DLC) underlayer were produced on AISI 440C stainless steel substrates by the hybrid technique of magnetron sputtering and pulsed-laser deposition. The resultant DLC films were characterized by Raman spectroscopy, scanning electron microscopy, and surface profilometry. Two types of wear experiment were conducted in this investioation: sliding friction experiments and fretting wear experiments. Unidirectional ball-on-disk sliding friction experiments were conducted to examine the wear behavior of an a-DLC/Ti-Ti(sub x) C(sub y)-DLC-coated AISI 440C stainless steel disk in sliding contact with a 6-mm-diameter AISI 440C stainless steel ball in ultrahigh vacuum, dry nitrogen, and humid air. Although the wear rates for both the coating and ball were low in all three environments, the humid air and dry nitrogen caused mild wear with burnishing, in the a-DLC top layer, and the ultrahigh vacuum caused relatively severe wear with brittle fracture in both the a-DLC top layer and the Ti-Ti(sub x) C(sub y)-DLC underlayer. For reference, amorphous hydrogenated carbon (H-DLC) films produced on a-DLC/Ti-Ti(sub x) C(sub y)-DLC nanocomposite coatings by using an ion beam were also examined in the same manner. The H-DLC films markedly reduced friction even in ultrahigh vacuum without sacrificing wear resistance. The H-DLC films behaved much like the a-DLC/Ti-Ti(sub x) C(sub y)-DLC nanocomposite coating in dry nitrogen and humid air, presenting low friction and low wear. Fretting wear experiments were conducted in humid air (approximately 50% relative humidity) at a frequency of 80 Hz and an amplitude of 75 micron on an a

An integrated approach to fire penetration seal program management

International Nuclear Information System (INIS)

Rispoli, R.D.

1996-01-01

This paper discusses the utilization of a P.C. based program to facilitate the management of Entergy Operations Arkansas Nuclear One (ANO) fire barrier penetration seal program. The computer program was developed as part of a streamlining process to consolidate all aspects of the ANO Penetration Seal Program under one system. The program tracks historical information related to each seal such as maintenance activities, design modifications and evaluations. The program is integrated with approved penetration seal design details which have been substantiated by full scale fire tests. This control feature is intended to prevent the inadvertent utilization of an unacceptable penetration detail in a field application which may exceed the parameters tested. The system is also capable of controlling the scope of the periodic surveillance of penetration seals by randomly selecting the inspection population and generating associated inspection forms. Inputs to the data base are required throughout the modification and maintenance process to ensure configuration control and maintain accurate data base information. These inputs are verified and procedurally controlled by Fire Protection Engineering (FPE) personnel. The implementation of this system has resulted in significant cost savings and has minimized the allocation of resources necessary to ensure long term program viability

Rotary shaft seal

International Nuclear Information System (INIS)

Langebrake, C.O.

1984-01-01

The invention is a novel rotary shaft seal assembly which provides positive-contact sealing when the shaft is not rotated and which operates with its sealing surfaces separated by a film of compressed ambient gas whose width is independent of the speed of shaft rotation. In a preferred embodiment, the assembly includes a disc affixed to the shaft for rotation therewith. Axially movable, non-rotatable plates respectively supported by sealing bellows are positioned on either side of the disc to be in sealing engagement therewith. Each plate carries piezoelectric transducer elements which are electrically energized at startup to produce films of compressed ambient gas between the confronting surfaces of the plates and the disc. Following shutdown of the shaft, the transducer elements are de-energized. A control circuit responds to incipient rubbing between the plate and either disc by altering the electrical input to the transducer elements to eliminate rubbing

Rock Melt Borehole Sealing System, Final Technical Report for SBIR Phase I Grant No. DE-SC0011888

Energy Technology Data Exchange (ETDEWEB)

Osnes, John D. [RE/SPEC Inc., Argonne, IL (United States); Vining, Cody A. [RE/SPEC Inc., Argonne, IL (United States); Nopola, Jay R. [RE/SPEC Inc., Argonne, IL (United States); Roggenthen, William M. [South Dakota School of Mines & Technology, Rapid City, SD (United States)

2015-03-19

Purpose of Research Deep borehole disposal is one option that has received attention in recent years as a possible strategy for long-term disposal of the tens of thousands of tons of spent nuclear fuel. The feasibility of the deep borehole option relies upon designing and constructing an effective seal within the borehole to ensure that the waste package does not communicate with the shallow subsurface biosphere through the borehole itself. Some of the uncertainty associated with the long-term suitability of the deep borehole option is related to (1) the degradation of traditional sealing materials over time and (2) the inability of traditional sealing methods to adequately seal a Disturbed Rock Zone surrounding the borehole. One possible system to address these concerns consists of encapsulating the waste in a melt generated from either the waste itself or a plug above the waste. This current project expanded on previous work to further advance the deep borehole disposal concept. Research Objectives & Findings The overarching objective of the study was to evaluate the feasibility of constructing a downhole heater that is capable of meeting the technical and logistical requirements to melt rock. This ultimate objective was accomplished by two primary approaches. The first approach was to define the heater requirements and conceptually design a system that is capable of melting rock. The second approach was to determine the feasibility of conducting an in situ, field-scale melting experiment to validate the suitability of the rock melt seal concept. The evaluation and conceptual design of the heater system resulted in the following primary findings: • Borehole wall temperatures capable of producing a partial melt are achievable under most expected thermal conductivities with a 12-kilowatt heater. • Commercially available components have been identified that meet the requirements of the heater system, including resistive elements that are capable of providing the

Systematic management of sealed source and nucleonic counting system in field service

International Nuclear Information System (INIS)

Mahadi Mustapha; Mohd Fitri Abdul Rahman; Jaafar Abdullah

2005-01-01

PAT group have received a lot of service from the oil and gas plant. All the services use sealed source and nucleonic counting system. This paper described the detail of management before going to the field service. This management is important to make sure the job is smoothly done and safe to the radiation worker and public. Furthermore this management in line with the regulation from LPTA. (Author)

Core disruptive accident margin seal

International Nuclear Information System (INIS)

Golden, M.P.

1979-01-01

An apparatus for sealing the annulus defined within a substantially cylindrical rotatable riser assembly and plug combination of a nuclear reactor closure head is described. The apparatus comprises an inflatable sealing mechanism disposed in one portion of the riser assembly near the annulus such that upon inflation the sealing mechanism is radially actuated against the other portion of the riser assembly thereby sealing the annulus. The apparatus further comprises a connecting mechanism which places one end of the sealing mechanism in fluid communication with the reactor cover gas so that overpressurization of the reactor cover gas will increase the radial actuation of the sealing mechanism thus enhancing sealing of the annulus

Improved circumferential shaft seal

Science.gov (United States)

Ludwig, L. P.; Strom, T. N.

1974-01-01

Comparative tests of modified and unmodified carbon ring seals showed that addition of helical grooves to conventional segmented carbon ring seals reduced leakage significantly. Modified seal was insensitive to shaft runout and to flooding by lubricant.

Seals for sealing a pressure vessel such as a nuclear reactor vessel or the like

International Nuclear Information System (INIS)

Bruns, H.J.; Huelsermann, K.H.

1975-01-01

A description is given of seals for sealing a pressure vessel such as a nuclear reactor vessel, steam boiler vessel, or any other vessel which is desirably sealed against pressure of the type including a housing and a housing closure that present opposed vertical sealing surfaces which define the sides of a channel. The seals of the present invention comprise at least one sealing member disposed in the channel, having at least one stop face, a base portion and two shank portions extending from the base portion to form a groove-like recess. The shank portions are provided with sealing surfaces arranged to mate with the opposed vertical pressure vessel sealing surfaces. A shank-spreading wedge element also disposed in the channel has at least one stop face and is engaged in the groove-like recess with the sealing member and wedge element stop face adjacent to each other

Testing of molded high temperature plastic actuator road seals for use in advanced aircraft hydraulic systems

Science.gov (United States)

Waterman, A. W.; Huxford, R. L.; Nelson, W. G.

1976-01-01

Molded high temperature plastic first and second stage rod seal elements were evaluated in seal assemblies to determine performance characteristics. These characteristics were compared with the performance of machined seal elements. The 6.35 cm second stage Chevron seal assembly was tested using molded Chevrons fabricated from five molding materials. Impulse screening tests conducted over a range of 311 K to 478 K revealed thermal setting deficiencies in the aromatic polyimide molding materials. Seal elements fabricated from aromatic copolyester materials structurally failed during impulse cycle calibration. Endurance testing of 3.85 million cycles at 450 K using MIL-H-83283 fluid showed poorer seal performance with the unfilled aromatic polyimide material than had been attained with seals machined from Vespel SP-21 material. The 6.35 cm first stage step-cut compression loaded seal ring fabricated from copolyester injection molding material failed structurally during impulse cycle calibration. Molding of complex shape rod seals was shown to be a potentially controllable technique, but additional molding material property testing is recommended.

WIPP [Waste Isolation Pilot Plant] panel entryway seal: Numerical simulation of seal composite interaction for preliminary design evaluation

International Nuclear Information System (INIS)

Argueello, J.G.

1988-04-01

This report presents the results of a series of structural analyses performed to evaluate the structural interaction of the components of a potential two-component panel entryway seal configuration with each other and with the rock salt formation at the repository horizon of the Waste Isolation Pilot Plant. A two-dimensional axisymmetric geomechanical model is used to numerically simulate the interaction of the components of a 30.48 m (100 ft) long seal, consisting of concrete end caps and a crushed salt core, with each other and with the surrounding formation. Issues addressed in this report pertain to the consolidation of the crushed salt in terms of how much of the seal core reaches effective consolidation in the presence of the stiff concrete end caps since these could conceivably cause bridging (retardation of closure around the core) to occur. In addition, the stress field in the end caps is evaluated to determine if the concrete component maintains its integrity. The stresses induced in the surrounding formation are also evaluated to determine if the presence of the concrete component in the seal system results in a ''tightening'' of the formation around the seal. 20 refs., 43 figs., 2 tabs

Standard test method for ranking resistance of plastics to sliding wear using block-on-ring wear test—cumulative wear method

CERN Document Server

American Society for Testing and Materials. Philadelphia

2003-01-01

1.1 This test method covers laboratory procedures for determining the resistance of plastics to sliding wear. The test utilizes a block-on-ring friction and wear testing machine to rank plastics according to their sliding wear characteristics against metals or other solids. 1.2 An important attribute of this test is that it is very flexible. Any material that can be fabricated into, or applied to, blocks and rings can be tested. Thus, the potential materials combinations are endless. In addition, the test can be run with different gaseous atmospheres and elevated temperatures, as desired, to simulate service conditions. 1.3 Wear test results are reported as the volume loss in cubic millimetres for the block and ring. Materials of higher wear resistance will have lower volume loss. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with it...

Seals in nuclear reactors

International Nuclear Information System (INIS)

1979-01-01

The seals described are for use in a nuclear reactor where there are fuel assemblies in a vessel, an inlet and an outlet for circulating a coolant in heat transfer relationship with the fuel assemblies and a closure head on the vessel in a tight fluid relationship. The closure head comprises rotatable plugs which have mechanical seals disposed in the annulus around each plug while allowing free rotation of the plug when the seal is not actuated. The seal is usually an elastomer or copper. A means of actuating the seal is attached for drawing it vertically into the annulus for sealing. When the reactor coolant is liquid sodium, contact with oxygen must be avoided and argon cover gas fills the space between the bottom of the closure head and the coolant liquid level and the annuli in the closure head. (U.K.)

Investigation of positive shaft seals

Science.gov (United States)

Pfouts, J. O.

1970-01-01

Welded metal bellows secondary seals prevent secondary seal leakage with a minimum number of potential leak paths. High performance seal is obtained by controlling the potentially unstable seal-face movements induced by mechanical vibrations and fluid pressure pulsations.

Continuous improvement of pump seals

International Nuclear Information System (INIS)

Wong, W.; Eyvindson, A.; Rhodes, D.B.

2003-01-01

Pump seal reliability continues to be an area needing improvement and ongoing vigilance. Methods have been developed for identifying and assessing factors relating to seal performance, selecting the most relevant ones for a specific station, and then focusing on the most significant aspects and how to improve. Discussion invariably addresses maintenance practices, seal design, monitoring capabilities, operating conditions, transients, and pump and motor design. Success in reliability improvement requires ongoing dialogue among the station operators, pump manufacturers and seal designers. AECL CAN-seals lead the nuclear industry in reliability and seal life. They effectively save operators millions of dollars in outage time and person-rem. This paper describes some of the significant developments in AECL's ongoing program in seal R and D, as well as recent new installations following the most demanding seal qualification programs to date. (author)

Recent developments in the use of plastic optical fiber for an embedded wear sensor

Science.gov (United States)

Cohen, Edward I.; Mastro, Stephen A.; Nemarich, Christopher P.; Korczynski, Joseph F., Jr.; Jarrett, Andrew W.; Jones, Wayne C.

1999-05-01

This paper describes recent developments of a practical, low cost embedded plastic optical fiber (POF) wear sensor system for the condition based maintenance of external outboard water lubricated bearings aboard U.S. Navy Ships. The benefit of this measurement system over the status quo is the ability to remotely monitor bearing wear. The Embedded Wear Sensor system (Navy invention disclosure #78,570) features a sacrificial wear fiber embedded into the nitrile rubber bearing. This fiber may also act as a conduit for the transmission of pressure and temperature data that may be resolved into alignment data. The authors selected a commercially-off-the- shelf plastic fiber for the sensor because of its material compatibility with the nitrile rubber bearing staves in terms of flexural modulus and wear properties. Presented herein is a description of the system concept, the results of non-linear finite element analysis, market survey of POF, mold studies, small scale prototyping and abrasive wear testing. A description of the sensor concept and the results of the preliminary finite element analysis of the bearing stave geometry are presented. Preliminary results of molding and glue bonding POF in nitrile rubber and then abrasive wear testing indicate that this is a viable concept.

Friction measurement in a hip wear simulator.

Science.gov (United States)

Saikko, Vesa

2016-05-01

A torque measurement system was added to a widely used hip wear simulator, the biaxial rocking motion device. With the rotary transducer, the frictional torque about the drive axis of the biaxial rocking motion mechanism was measured. The principle of measuring the torque about the vertical axis above the prosthetic joint, used earlier in commercial biaxial rocking motion simulators, was shown to sense only a minor part of the total frictional torque. With the present method, the total frictional torque of the prosthetic hip was measured. This was shown to consist of the torques about the vertical axis above the joint and about the leaning axis. Femoral heads made from different materials were run against conventional and crosslinked polyethylene acetabular cups in serum lubrication. Regarding the femoral head material and the type of polyethylene, there were no categorical differences in frictional torque with the exception of zirconia heads, with which the lowest values were obtained. Diamond-like carbon coating of the CoCr femoral head did not reduce friction. The friction factor was found to always decrease with increasing load. High wear could increase the frictional torque by 75%. With the present system, friction can be continuously recorded during long wear tests, so the effect of wear on friction with different prosthetic hips can be evaluated. © IMechE 2016.

Monitoring wear and corrosion in industrial machines and systems: A radiation tool

International Nuclear Information System (INIS)

Konstantinov, I.O.; Zatolokin, B.V.

1994-01-01

Industrial equipment and machines, transport systems, nuclear and conventional power plants, pipelines, and other materials is substantially influenced by degradation processes such as wear and corrosion. For safety and economic reasons, appropriately monitoring the damage could prevent dangerous accidents. When the surfaces of machine parts under investigation are not easy to reach or are concealed by overlying structures, nuclear methods have become powerful tools for examination. They include X-ray radiography, neutron radiography, and a technique known as thin layer activation (TLA)

Passive Wake Detection Using Seal Whisker-Inspired Sensing

Science.gov (United States)

2015-02-01

companion. The redemption, love, and joy that have come from our time together are written between 6 each line here. Mom, Dad , Jenn, and Robert: thank...specific study is described. 1.1.1 Pinniped Sensory Systems As with many animals, the sensory systems available to the harbor seal are rich and diverse...shifts the mag- netic field (Figure 1-4b). In these test conditions, the seal exhibited poor ability to detect the change. Olfaction There is evidence

Friction and wear methodologies for design and control

CERN Document Server

Straffelini, Giovanni

2015-01-01

This book introduces the basic concepts of contact mechanics, friction, lubrication, and wear mechanisms, providing simplified analytical relationships that are useful for quantitative assessments. Subsequently, an overview on the main wear processes is provided, and guidelines on the most suitable design solutions for each specific application are outlined. The final part of the text is devoted to a description of the main materials and surface treatments specifically developed for tribological applications and to the presentation of tribological systems of particular engineering relevance. The text is up to date with the latest developments in the field of tribology and provides a theoretical framework to explain friction and wear problems, together with practical tools for their resolution. The text is intended for students on Engineering courses (both bachelor and master degrees) who must develop a sound understanding of friction, wear, lubrication, and surface engineering, and for technicians or professi...

Prospective randomized trial compares suction versus water seal for air leaks.

Science.gov (United States)

Cerfolio, R J; Bass, C; Katholi, C R

2001-05-01

Surgeons treat air leaks differently. Our goal was to evaluate whether it is better to place chest tubes on suction or water seal for stopping air leaks after pulmonary surgery. A second goal was to evaluate a new classification system for air leaks that we developed. Patients were prospectively randomized before surgery to receive suction or water seal to their chest tubes on postoperative day (POD) #2. Air leaks were described and quantified daily by a classification system and a leak meter. The air-leak meter scored leaks from 1 (least) to 7 (greatest). The group randomized to water seal stayed on water seal unless a pneumothorax developed. On POD #2, 33 of 140 patients had an air leak. Eighteen patients had been preoperatively randomized to water seal and 15 to suction. Air leaks resolved in 12 (67%) of the water seal patients by the morning of POD #3. All 6 patients whose air leak did not stop had a leak that was 4/7 or greater (p leak meter. Of the 15 patients randomized to suction, only 1 patient's air leak (7%) resolved by the morning of POD #3. The randomization aspect of the trial was ended and statistical analysis showed water seal was superior (p = 0.001). The remaining 14 patients were then placed to water seal and by the morning of POD #4, 13 patients' leaks had stopped. Of the 32 total patients placed to seal, 7 (22%) developed a pneumothorax and 6 of these 7 patients had leaks that were 4/7 or greater (p = 0.001). Placing chest tubes on water seal seems superior to wall suction for stopping air leaks after pulmonary resection. However, water seal does not stop expiratory leaks that are 4/7 or greater. Pneumothorax may occur when chest tubes are placed on seal with leaks this large.

Management of Disused Radioactive Sealed Sources in Egypt - 13512

International Nuclear Information System (INIS)

Mohamed, Y.T.; Hasan, M.A.; Lasheen, Y.F.

2013-01-01

The future safe development of nuclear energy and progressive increasing use of sealed sources in medicine, research, industry and other fields in Egypt depends on the safe and secure management of disused radioactive sealed sources. In the past years have determined the necessity to formulate and apply the integrated management program for radioactive sealed sources to assure harmless and ecological rational management of disused sealed sources in Egypt. The waste management system in Egypt comprises operational and regulatory capabilities. Both of these activities are performed under legislations. The Hot Laboratories and Waste Management Center HLWMC, is considered as a centralized radioactive waste management facility in Egypt by law 7/2010. (authors)

A wear-resistant zirconia ceramic for low friction application

International Nuclear Information System (INIS)

Winnubst, A.J.A.; Ran, S.; Wiratha, K.W.; Blank, D.H.A.; Pasaribu, H.R.; Sloetjes, J.W.; Schipper, D.J.

2004-01-01

A high wear-resistant ceramic/ceramic couple is described associated with low friction. By adding a small amount CuO to yttria-doped tetragonal zirconia (Y-TZP) the (dry) coefficient of friction against alumina is only 0.2 during a sliding distance of 3-5 km after which the coefficient drastically increases and a transition from mild to sever wear occurs. Pure Y-TZP exhibits a coefficient of friction of 0.7 under the same experimental conditions but wear remains mild during the test (upto 10 km of sliding distance). These small amounts of CuO also strongly influence the densification behaviour. Sintering of this system occurs in several steps where among other things dissolution of CuO in the Y-TZP matrix as well as liquid phase sintering takes place. Non-uniform shrinkage of the CuO-doped system resulting in relative large microcracks in the ceramic can explain its sudden drastic increase in coefficient of friction and wear rate after 3-5 km of operation. (orig.)

Sealing properties of a self-etching primer system to normal caries-affected and caries-infected dentin.

Science.gov (United States)

Lee, Kwang-Won; Son, H-H; Yoshiyama, Masatoshi; Tay, Franklin R; Carvalho, Ricardo M; Pashley, David H

2003-09-01

To compare the ability of an experimental antibacterial self-etching primer adhesive system to seal exposure sites in normal, caries-affected and caries-infected human dentin. 30 extracted human third molars were used within 1 month of extraction. 10 intact normal teeth comprised the normal group. 20 teeth with occlusal caries that radiographically extended halfway to the pulp were excavated using caries-detector solution (CDS) and a #4 round carbide bur in a slowspeed handpiece. Half of those teeth were fully excavated free of CDS-stained material without exposing the pulp, and were designated as the caries-affected dentin group. The remaining 10 teeth were excavated as close to the pulp as possible without obtaining an exposure, but whose dentin continued to stain red with CDS; this group was designated as the caries-infected dentin group. The remaining dentin thickness in all of the specimens in the other two groups was then reduced to the same extent as the caries-infected group. Direct exposures of the pulp chamber were made with a 1/4 round bur in the normal dentin or a 25 gauge needle in the other two groups. After measuring the fluid flow through the exposure, the sites were then sealed with an experimental antibacterial fluoride-containing self-etching primer adhesive systems (ABF). Fluid conductance was remeasured every week for 16 weeks. The fluid conductance through the exposure fell 99% in all groups following resin sealing. The seals of normal and caries-affected dentin remained relatively stable over the 16 weeks, while the seals of caries-infected dentin gradually deteriorated, reaching significance at 8 weeks. TEM examination revealed very thin (ca. 0.5 mm) hybrid layers in normal dentin, 3-4 microm thick hybrid layers in caries-affected dentin and 40 microm thick hybrid layers in caries-infected dentin. The tubules of caries-infected dentin were enlarged and filled with bacteria. Resin tags passed around these bacteria in the top 20-40 microm

Electrostatic and tribological phenomena and their effect on the braking torque in the shaft-oil-lip seal system

Science.gov (United States)

Gajewski, Juliusz B.; Glogowski, Marek J.

2008-12-01

The former research [1] was carried out on the influence of tribocharging in a system: metal rotating shaft-oil-lip seal on its work, especially on changes in the shaft braking torque with the increasing angular shaft velocity and oil temperature. The results obtained suggested that there be a possibility of reducing the braking torque by an external electric field. The compensation for the electric field generated in the system by natural tribocharging was proposed. The reduction in the braking torque seemed possible while applying an external DC electric field to the system. In general, the torque tended to increase with the increasing DC electric field for a variety of the oils and lip seals used and for different shaft angular velocities (rotational speeds) and oil temperatures. The braking torque reduction was achieved only for one lip seal and some different oils, which was and is a promising, expected result. The research results were yet presented elsewhere [1-3] and here some novel attempt has been made to interpret the results obtained in their physical—tribological and especially electrostatic—aspects since there has been a lack of such an interpretation in the literature of the subject.

Electrostatic and tribological phenomena and their effect on the braking torque in the shaft-oil-lip seal system

International Nuclear Information System (INIS)

Gajewski, Juliusz B; Glogowski, Marek J

2008-01-01

The former research was carried out on the influence of tribocharging in a system: metal rotating shaft-oil-lip seal on its work, especially on changes in the shaft braking torque with the increasing angular shaft velocity and oil temperature. The results obtained suggested that there be a possibility of reducing the braking torque by an external electric field. The compensation for the electric field generated in the system by natural tribocharging was proposed. The reduction in the braking torque seemed possible while applying an external DC electric field to the system. In general, the torque tended to increase with the increasing DC electric field for a variety of the oils and lip seals used and for different shaft angular velocities (rotational speeds) and oil temperatures. The braking torque reduction was achieved only for one lip seal and some different oils, which was and is a promising, expected result. The research results were yet presented elsewhere [1-3] and here some novel attempt has been made to interpret the results obtained in their physical-tribological and especially electrostatic-aspects since there has been a lack of such an interpretation in the literature of the subject.

Problems of locomotive wheel wear in fleet replacement

Directory of Open Access Journals (Sweden)

L.P. Lingaytis

2013-08-01

Full Text Available Purpose. To conduct a research and find out the causes of defects appearing on the wheel thread of freight locomotives 2М62 and SIEMENS ER20CF. Methodology. To find the ways to solve this problem comparing the locomotive designs and their operating conditions. Findings. After examining the nature of the wheel wear the main difference was found: in locomotives of the 2M62 line wears the wheel flange, and in the locomotives SIEMENS ER20CF – the tread surface. After installation on the 2M62 locomotive the lubrication system of flanges their wear rate significantly decreased. On the new freight locomotives SIEMENS ER20CF the flange lubrication systems of the wheel set have been already installed at the factory, however the wheel thread is wearing. As for locomotives 2M62, and on locomotives SIEMENS ER20CF most wear profile skating wheels of the first wheel set. On both locomotive lines the 2М62 and the SIEMENS ER20CF the tread profile of the first wheel set most of all is subject to the wear. After reaching the 170 000 km run, the tread surface of some wheels begins to crumble. There was a suspicion that the reason for crumb formation of the wheel surface may be insufficient or excessive wheel hardness or its chemical composition. In order to confirm or deny this suspicion the following studies were conducted: the examination of the rim surface, the study of the wheel metal hardness and the document analysis of the wheel production and their comparison with the results of wheel hardness measurement. Practical value. The technical condition of locomotives is one of the bases of safety and reliability of the rolling stock. The reduction of the wheel wear significantly reduces the operating costs of railway transport. After study completion it was found that there was no evidence to suggest that the ratio of the wheel-rail hardness could be the cause of the wheel surface crumbling.

Ferrules seals

Science.gov (United States)

Smith, J.L.

1984-07-10

A device is provided for sealing an inner tube and an outer tube without excessively deforming the tubes. The device includes two ferrules which cooperate to form a vacuum-tight seal between the inner tube and outer tube and having mating surfaces such that overtightening is not possible. 3 figs.

A magnetic fluid seal for rotary blood pumps: effects of seal structure on long-term performance in liquid.

Science.gov (United States)

Mitamura, Yoshinori; Takahashi, Sayaka; Amari, Shuichi; Okamoto, Eiji; Murabayashi, Shun; Nishimura, Ikuya

2011-03-01

A magnetic fluid (MF) seal enables mechanical contact-free rotation of the shaft and hence has excellent durability. The performance of an MF seal, however, has been reported to decrease in liquids. We developed an MF seal that has a "shield" mechanism, and a new MF with a higher magnetization of 47.9 kA/m. The sealing performance of the MF seal installed in a rotary blood pump was studied. Three types of MF seals were used. Seal A was a conventional seal without a shield. Seal B had the same structure as that of Seal A, but the seal was installed at 1 mm below liquid level. Seal C was a seal with a shield and the MF was set at 1 mm below liquid level. Seal A failed after 6 and 11 days. Seal B showed better results (20 and 73 days). Seal C showed long-term durability (217 and 275 days). The reason for different results in different seal structures was considered to be different flow conditions near the magnetic fluid. Fluid dynamics near the MF in the pump were analyzed using computational fluid dynamics (CFD) software. We have developed an MF seal with a shield that works in liquid for >275 days. The MF seal is promising as a shaft seal for rotary blood pumps.

Electronically controlled mechanical seal for aerospace applications--Part 2: Transient tests

Science.gov (United States)

Wolff, Paul J.; Salant, Richard F.

1995-01-01

An electronically controlled mechanical seal for use as the purge gas seal in a liquid oxygen turbopump has been fabricated and tested under transient operating conditions. The thickness of the lubricating film is controlled by adjusting the coning of the carbon face. This is accomplished by applying a voltage to a piezoelectric actuator to which the carbon face is bonded. The seal has been operated with a closed-loop control system that utilizes either the leakage rate or seal face temperature as the feedback. Both speed and pressure transients have been imposed on the seal. The transient tests have demonstrated that the seal is capable of maintaing low leakage rates while limiting face temperatures.

Borehole sealing method and apparatus

International Nuclear Information System (INIS)

Hartley, J.N.; Jansen, G. Jr.

1977-01-01

A method and apparatus is described for sealing boreholes in the earth. The borehole is blocked at the sealing level, and a sealing apparatus capable of melting rock and earth is positioned in the borehole just above seal level. The apparatus is heated to rock-melting temperature and powdered rock or other sealing material is transported down the borehole to the apparatus where it is melted, pooling on the mechanical block and allowed to cool and solidify, sealing the hole. Any length of the borehole can be sealed by slowly raising the apparatus in the borehole while continuously supplying powdered rock to the apparatus to be melted and added to the top of the column of molten and cooling rock, forming a continuous borehole seal. The sealing apparatus consists of a heater capable of melting rock, including means for supplying power to the heater, means for transporting powdered rock down the borehole to the heater, means for cooling the apparatus and means for positioning the apparatus in the borehole. 5 claims, 1 figure

Systemic distribution of wear debris after hip replacement. A cause for concern?

Science.gov (United States)

Langkamer, V G; Case, C P; Heap, P; Taylor, A; Collins, C; Pearse, M; Solomon, L

1992-11-01

The production of particulate wear debris is a recognised complication of joint arthroplasty, but interest has concentrated on local tissue reactions and a possible association with implant loosening. The fate of wear products in the body remains unknown, although some of the metals used in the construction of orthopaedic implants are known to have toxic and oncogenic properties. We report histological and electron-microscopic evidence from two cases which shows that metallic debris can be identified in the lymphoreticular tissues of the body distant from the hip some years after joint replacement. The increase in the use of total arthroplasty in younger patients, the development of new alloys and the use of porous coatings must raise concern for the long-term effects of the accumulation of wear debris in the body.

Tunnel sealing: concept and feasibility evidence

International Nuclear Information System (INIS)

Brenner, R.P.; Eppinger, G.; Mettler, K.

1991-01-01

-disturbed zone. The sealed tunnel is not a preferential pathway when considering the large-scale characteristics of the rock mass surrounding the repository system. (author) figs., tabs., 39 refs

Effects of the presence of official-looking volunteers on harassment of New Zealand fur seals.

Science.gov (United States)

Acevedo-Gutiérrez, Alejandro; Acevedo, Lisa; Boren, Laura

2011-06-01

An increased number of tourists viewing animals in the wild have increased stress on these animals (hereafter wildlife). Many wildlife-viewing locations rely on voluntary compliance with posted regulations to protect animals from tourists because of the expense of employing on-site enforcement personnel. Voluntary compliance, however, is ineffective. The presence of official-looking volunteers may decrease the incidence of wildlife harassment by tourists. To test this possibility, we observed tourists interacting with 5- to 12-month-old New Zealand fur seals (Arctocephalus forsteri) at the popular Ohau Stream waterfall while in the absence or presence of a young woman in plain sight wearing a neon vest (i.e., observer) and when an observer was not present. We observed 254 tourist groups at the waterfall when young seals were present. The percentage of groups in which at least one person harassed (approached, touched, or threw objects) a young seal was two-thirds lower when the official-looking observer was present. Frequency of harassment was inversely related to observer presence. Programs in which volunteers work at tourist sites are popular in countries with high tourism rates, such as New Zealand. Our results show that a relatively inexpensive and effective tourism-management strategy may be to post such volunteers as observers at sites where tourists view wildlife. ©2010 Society for Conservation Biology.

Radioisotopic measurement methods for determining the wear railway brake shoe and its rim wearing effect

International Nuclear Information System (INIS)

Doman, P.

1979-01-01

Under operating conditions the wear of brake shoe was tested by a measuring method based on the principle of radioisotopic thickness measurement. It is characteristic to the sensitivity of the method that the wear caused by the fast braking of a train (speed: 100 km/h) as well as the uneven wear distribution were determinable. Surface activating methods assuring the periodic and continuous evaluation were also developed. A test was performed with galvanic surface activation under operating conditions to determine the rim wearing effect of the brake shoe. Apart from the operational tests a new method based on activated wear measurement was also developed. (author)

Research on the effect of wear-ring clearances to the axial and radial force of a centrifugal pump

International Nuclear Information System (INIS)

Zhao, W G; Qi, C X; Li, Y B; He, M Y

2013-01-01

Varying of the wear-ring clearance not only has a distinct effect on the volumetric loss of the centrifugal pump, but also on the performance of the centrifugal pump including the axial and radial forces. Comparing with the experimental studies, numerical simulation methods have some special advantages, such as the low cost, fast and high efficiency, and convenient to get the detailed structure of the internal flow characteristics, so it has been widely used in the fluid machinery study in recent years. In order to study the effect of wear-ring clearance on the force performance of the centrifugal pump, based on the Reynolds Time-Averaged N-S equations and RNG k-ε turbulence model, a centrifugal pump with three variable styles of the wear-rings was simulated: Only the clearance of the front wear-ring was changed, only the clearance of the back wear-ring was changed and both were changed. Comparing with the experiment, numerical results show a good agreement. In the three changing styles of the clearance, the variable of the clearance of front wear-ring has the most influence on the axial force of the centrifugal pump, while has tiny effect on the radial force for all the conditions

Sealing properties of mechanical seals for an axial flow blood pump.

Science.gov (United States)

Tomioka, J; Mori, T; Yamazaki, K; Koyanagi, H

1999-08-01

A miniature intraventricular axial flow blood pump for left ventricular support is under development. One of the key technologies required for such pumps is sealing of the motor shaft. In this study, to prevent blood backflow into the motor side, mechanical seals were developed and their sealing properties investigated. In the experimental apparatus, the mechanical seal separated the bovine blood on the chamber side from the cooling water on the motor side. A leakage of the blood was measured by inductively coupled plasma (ICP) light emission analysis. The rate of hemolysis was measured by the cyanmethemoglobin method. Frictional torque acting on the shaft was measured by a torque transducer. In the experiments, the rotational speed of the shaft was changed from 1,000 to 10,000 rpm, and the contact force of the seal faces was changed from 1.96 to 4.31 N. To estimate lubrication regimes, the Stribeck curve, a diagram of the coefficient of friction against the bearing characteristic G number, was drawn. The results of the experiments showed that both the leakage of blood and the rate of hemolysis were very small. The friction loss was also very small. The mechanical seal was operated in various lubrication regimes, from a fluid lubrication regime to a mixed lubrication regime.

Friction and wear of TiCN coatings deposited by filtered arc

International Nuclear Information System (INIS)

Huang, S.W.; Ng, K.; Samandi, M.

1998-01-01

A series of macroparticle-free TiN, TiCN and TiC coatings were deposited on 316 austenitic stainless steel using a titanium target in a filtered arc deposition system and reactive mixtures of CH4 and N2 gases. The microhardness of the coatings were measured by using an Ultra Microhardness Indentation System (UMIS-2000). The wear and friction of the coatings were assessed under controlled test conditions in a pin-on-disc tribometer. The results show a significant increase in microhardness and wear resistance as the CH4 :N2 gas flow rate ratio is increased. At lower load (14N), all coatings exhibited low friction and wear. At higher load (25N), the higher carbon content TiCN and TiC coatings showed a much lower friction and wear compared to TiN and low carbon TiCN. The topographical examination of coatings and worn surfaces established that the self-lubricating effect of the carbonaceous particles condensed from the plasma during the deposition was primarily responsible for the low friction and wear regime. (authors)

Conceptual design of shaft seals for a nuclear waste disposal vault

Energy Technology Data Exchange (ETDEWEB)

NONE

1993-04-01

The concept of a disposal vault in the Canadian Shield for the effective isolation of nuclear fuel wastes is being assessed as part of the Canadian Nuclear Fuel Waste Management Program. The vault would be accessed from the surface by a number of shafts, which would likely penetrate the vault environment and intersect significant rock fractures and thereby form preferential pathways for the migration of radionuclides from the disposal area to the biosphere. Golder Associates were retained to conduct a conceptual design study of sealing and backfilling the shafts. The first volume of this report reviews current shaft sinking and lining technologies, and recommends the preferred construction methods for the shafts. Factors that could affect the design of a shaft seal system are reviewed, and a conceptual shaft seal is proposed. The second volume addresses the performance assessment of a shaft seal system. While there are no specific performance criteria against which to compare the anticipated containment characteristics of the shaft seal system proposed, the methodology developed for the performance assessment of the reference design should enable the design to be modified to meet performance criteria as they are developed. The report estimates that it will cost $133.7 million in 1986 Canadian dollars to seal three reference shafts, including $18 million for labour and equipment, $103.4 million for backfill and sealing materials, $9.5 million for project indirect costs, and $2.8 million project management. (author). 53 refs., 36 tabs., 43 figs.

Conceptual design of shaft seals for a nuclear waste disposal vault

International Nuclear Information System (INIS)

1993-04-01

The concept of a disposal vault in the Canadian Shield for the effective isolation of nuclear fuel wastes is being assessed as part of the Canadian Nuclear Fuel Waste Management Program. The vault would be accessed from the surface by a number of shafts, which would likely penetrate the vault environment and intersect significant rock fractures and thereby form preferential pathways for the migration of radionuclides from the disposal area to the biosphere. Golder Associates were retained to conduct a conceptual design study of sealing and backfilling the shafts. The first volume of this report reviews current shaft sinking and lining technologies, and recommends the preferred construction methods for the shafts. Factors that could affect the design of a shaft seal system are reviewed, and a conceptual shaft seal is proposed. The second volume addresses the performance assessment of a shaft seal system. While there are no specific performance criteria against which to compare the anticipated containment characteristics of the shaft seal system proposed, the methodology developed for the performance assessment of the reference design should enable the design to be modified to meet performance criteria as they are developed. The report estimates that it will cost $133.7 million in 1986 Canadian dollars to seal three reference shafts, including $18 million for labour and equipment, $103.4 million for backfill and sealing materials, $9.5 million for project indirect costs, and $2.8 million project management. (author). 53 refs., 36 tabs., 43 figs

Shaft sealing issue in CO2 storage sites

Science.gov (United States)

Dieudonné, A.-C.; Charlier, R.; Collin, F.

2012-04-01

Carbon capture and storage is an innovating approach to tackle climate changes through the reduction of greenhouse gas emissions. Deep saline aquifers, depleted oil and gas reservoirs and unmineable coal seams are among the most studied reservoirs. However other types of reservoir, such as abandonned coal mines, could also be used for the storage of carbon dioxide. In this case, the problem of shaft sealing appears to be particularly critical regarding to the economic, ecologic and health aspects of geological storage. The purpose of the work is to study shaft sealing in the framework of CO2 storage projects in abandoned coal mines. The problem of gas transfers around a sealing system is studied numerically using the finite elements code LAGAMINE, which has been developped for 30 years at the University of Liege. A coupled hydro-mechanical model of unsaturated geomaterials is used for the analyses. The response of the two-phase flow model is first studied through a simple synthetic problem consisting in the injection of gas in a concrete-made column. It stands out of this first modeling that the advection of the gas phase represents the main transfer mechanism of CO2 in highly unsaturated materials. Furthermore the setting of a bentonite barrier seal limits considerably the gas influx into the biosphere. A 2D axisymetric hydromechanical modeling of the Anderlues natural gas storage site is then performed. The geological and hydrogeological contexts of the site are used to define the problem, for the initial and boundary conditions, as well as the material properties. In order to reproduce stress and water saturation states in the shale before CO2 injection in the mine, different phases corresponding to the shaft sinking, the mining and the set up of the sealing system are simulated. The system efficiency is then evaluated by simulating the CO2 injection with the imposed pressure at the shaft wall. According to the modeling, the low water saturation of concrete and

Aerial surveys of seals at Rødsand seal sanctuary and adjacent haul-out sites

DEFF Research Database (Denmark)

Teilmann, J.; Dietz, R.; Edren, Susi M.C.

This report describes the preliminary results of aerial surveys at Rødsand seal sanctuary, southeast Denmark and adjacent seal haul-out sites in southwestern Baltic. The work was carried out in connection with studies of potential effects of the Nysted offshore wind farm. Rødsand seal sanctuary...... is a part of seal management area 4, and the area is believed to hold a more or less closed population with little exchange to other areas. Although the harbour seal is relatively stationary there may be movements between the haul-out sites in the area. A possible reaction to disturbance from...... the construction and operation of the wind farm may be that the seals use other haul-out sites to a higher extend....

Assessment of thermal spray coatings for wear and abrasion resistance applications

Science.gov (United States)

Karode, Ishaan Nitin

Thermal spray cermet and metallic coatings are extensively used for wear, abrasion and corrosion control in a variety of industries. The first part of the thesis focuses mainly on testing of sand erosion resistance of thermal spray coatings on carbon composites used in the manufacture of helicopter rotor blades. The test set-up employed is a sand blasting machine and is an effort to duplicate the in-flight conditions especially those encountered in hot arid conditions. The technique adopted follows the Department of Defence test method standard. Carbon Composites have excellent stiffness, strength and low weight/density. The strength to weight ratio is high. Hence, these are used in aerospace applications to a large extent. However, the biggest problem encountered with carbon composites is its low abrasion resistance as its surface is very weak. Hence, thermal spray coatings are used to improve the surface properties of CFRP. Zinc bond coats and WC-Co coatings were tested. However, high amount of thermal stresses were developed between the substrate and the coating due to large differences in the CTE's of the both, leading to high mass losses within two minutes and just 130 grams of sand sprayed on to the coatings with the sand blasting machine built; and hence the coatings with CC as a substrate could not qualify for the application. The second part of the thesis focuses on the assessment of different thermal spray coatings used for manufacture of mechanical seals in pumps and analyze the best coating material for the wear resistance application through detail quantification of material loss by block-on-ring test set-up. A machine based on Block-on-ring test set-up following ASTM G77 (Measurement of Adhesive wear resistance of thermal spray coatings) standards was built to duplicate the pump conditions. Thermally sprayed coated materials were tested in different conditions (Load, time, abrasive). WC-Co had the highest wear resistance (lower volume losses) and

Sealing materials for solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Larsen, P.H.

1999-02-01

A major obstacle in the achievement of high electrical efficiency for planar solid oxide fuel cell stacks (SOFC) is the need for long term stable seals at the operational temperature between 850 and 1000 deg. C. In the present work the formation and properties of sealing materials for SOFC stacks that fulfil the necessary requirements were investigated. The work comprises analysis of sealing material properties independently, in simple systems as well as tests in real SOFC stacks. The analysed sealing materials were based on pure glasses or glass-ceramic composites having B{sub 2}O{sub 3}, P{sub 2}O{sub 5} or siO{sub 2} as glass formers, and the following four glass systems were investigated: MgO/caO/Cr{sub 2}O{sub 3}-Al{sub 2}O{sub 3}B{sub 2}O{sub 3}-P{sub 2}O{sub 5}, MgO-Al{sub 2}O{sub 3}-P{sub 2}O{sub 5}, MgO-Al{sub 2}O{sub 3}-P{sub 2}O{sub 5}-SiO{sub 2} and BaO/Na{sub 2}O-Al{sub 2}O{sub 3}-SiO{sub 2}. (au) 32 tabs., 106 ills., 107 refs.

Long-term sealing of openings in salt formations

International Nuclear Information System (INIS)

Walter, F.; Stockmann, N.; Yaramanci, U.; Laurens, J.F.

1993-01-01

Radioactive wastes can be disposed of in deep salt formations. Rock salt is a suitable geologic medium because of its unique characteristics. Open boreholes, shafts and drifts are created to provide physical access to the repository. Long-term seals must be emplaced in those potential pathways to prevent radioactive release to the biosphere. The sealing materials must be mechanically and, most important, geochemically stable within the host rock. Salt bricks made of compressed salt-powder are understood to be the first choice long-term sealing material. Seals built from salt bricks will be ductile. The permeability of the salt bricks is assumed to be in the order of 2*10 -15 m 2 . Large sealing systems are built by combining the individual bricks with mortar. Raw materials for mortar are fine-grained halite powder and ground saliferous clay. The permeability of the mortar decreases with its salt content to approx. 2*10 -14 m 2 . Moistened saliferous clay may show temporary swelling. Sealing experiments will be carried out in the Asse salt mine. Long-term seals will be built into holes of 1 m diameter. The contact and merging of the brick-wall with the surrounding rock salt will be investigated in long-term tests. Within the in situ sealing program a number of geophysical methods are applied. Acoustic emission measurements are used to study the effects of high pressure gas injection and a geoelectrical observation program is aiming to estimate the permeability in and around the long-term seal. High frequency electromagnetic methods contribute to the knowledge of the petrophysical rock properties. 11 refs., 12 figs

Borehole sealing literature review of performance requirements and materials

International Nuclear Information System (INIS)

Piccinin, D.; Hooton, R.D.

1985-02-01

To ensure the safe disposal of nuclear wastes, all potential pathways for radionuclide release to the biosphere must be effectively sealed. This report presents a summary of the literature up to August 1982 and outlines the placement, mechanical property and durability-stability requirements for borehole sealing. An outline of the materials that have been considered for possible use in borehole sealing is also included. Cement grouts are recommended for further study since it is indicated in the literature that cement grouts offer the best opportunity of effectively sealing boreholes employing present technology. However, new and less well known materials should also be researched to ensure that the best possible borehole plugging system is developed. 78 refs

Salt repository sealing materials development program: 5-year work plan

International Nuclear Information System (INIS)

Myers, L.B.

1986-06-01

This plan covers 5 years (fiscal years 1986 through 1990) of work in the repository sealing materials program to support design decisions and licensing activities for a salt repository. The plan covers a development activity, not a research activity. There are firm deliverables as the end points of each part of the work. The major deliverables are: development plans for code development and materials testing; seal system components models; seal system performance specifications; seal materials specifications; and seal materials properties ''handbook.'' The work described in this plan is divided into three general tasks as follows: mathematical modeling; materials studies (salt, cementitious materials, and earthen materials); and large-scale testing. Each of the sections presents an overview, status, planned activities, and summary of program milestones. This plan will be the starting point for preparing the development plans described above, but is subject to change if preparation of the work plan indicates that a different approach or sequence is preferable to achieve the ultimate goal, i.e., support of design and licensing

Main-coolant-pump shaft-seal guidelines. Volume 2. Operational guidelines. Final report

International Nuclear Information System (INIS)

Fair, C.E.; Greer, A.O.

1983-03-01

This report presents a set of guidelines and criteria for improving main coolant pump shaft seal operational reliability. The noted guidelines are developed from EPRI sponsored nuclear power plant seal operating experience studies. Usage procedures/practices and operational environment influence on seal life and reliability from the most recent such survey are summarized. The shaft seal and its auxiliary supporting systems are discussed both from technical and operational related viewpoints

Design and Test of an Event Detector and Locator for the ReflectoActive Seals System

International Nuclear Information System (INIS)

Stinson, Brad J.

2006-01-01

The purpose of this work was to research, design, develop and test a novel instrument for detecting fiber optic loop continuity and spatially locating fiber optic breaches. The work is for an active seal system called ReflectoActive(trademark) Seals whose purpose is to provide real time container tamper indication. A Field Programmable Gate Array was used to implement a loop continuity detector and a spatial breach locator based on a high acquisition speed single photon counting optical time domain reflectometer. Communication and other control features were added in order to create a usable instrument that met defined requirements. A host graphical user interface was developed to illustrate system use and performance. The resulting device meets performance specifications by exhibiting a dynamic range of 27dB and a spatial resolution of 1.5 ft. The communication scheme used expands installation options and allows the device to communicate to a central host via existing Local Area Networks and/or the Internet.

Nuclear instrumentation cable end seal

International Nuclear Information System (INIS)

Cannon, C.P.; Brown, D.P.

1979-01-01

An improved coaxial end seal for hermetically sealed nuclear instrumentation cable exhibiting an improved breakdown pulse noise characteristic under high voltage, high temperature conditions is described. A tubular insulator body has metallized interior and exterior surface portions which are braze sealed to a center conductor and an outer conductive sheath. The end surface of the insulator body which is directed toward the coaxial cable to which it is sealed has a recessed surface portion within which the braze seal material terminates

Non-linear friction in reciprocating hydraulic rod seals: Simulation and measurement

International Nuclear Information System (INIS)

Bullock, A K; Tilley, D G; Johnston, D N; Bowen, C R; Keogh, P S

2009-01-01

Non-linear seal friction can impede the performance of hydraulic actuation systems designed for high precision positioning with favourable dynamic response. Methods for predicting seal friction are required to help develop sealing systems for this type of application. Recent simulation techniques have claimed progress, although have yet to be validated experimentally. A conventional reciprocating rod seal is analysed using established elastohydrodynamic theory and the mixed lubrication Greenwood-Williamson-average Reynolds model. A test rig was used to assess the accuracy of the simulation results for both instroke and outstroke. Inverse hydrodynamic theory is shown to predict a U 0.5 power law between rod speed and friction. Comparison with experimental data shows the theory to be qualitatively inaccurate and to predict friction levels an order of magnitude lower than those measured. It was not possible to model the regions very close to the inlet and outlet due to the high pressure gradients at the edges of the contact. The mixed lubrication model produces friction levels within the correct order of magnitude, although incorrectly predicts higher friction during instroke than outstroke. Previous experiments have reported higher friction during instroke than outstroke for rectangular seals, suggesting that the mixed lubrication model used could possibly be suitable for symmetric seals, although not for seal tribology in general.

An investigation of two-body abrasive wear of laser processed surfaces

International Nuclear Information System (INIS)

Abass, G.

1995-01-01

This paper reports two body abrasive wear studies of alloy and composite deposits produced with a 2 kW continuous wave CO/sub 2/ laser. Stellite alloy 6, Alloy 4815, Stainless steel and SiC powders were used to produce alloy and composite deposits on an En 3b mild steel substrate. The cladding material was injected into the laser produced melt pool by means of a pneumatic powder delivery system. In the present studies instead of using the conventional pin-on-disc method of wear measurement, a more realistic and practical wear testing procedure was adopted. The wear testing machine used was capable of measuring wear of three comparatively larger (30 x 30 x 10 mm) clad samples by abrading simultaneously against a revolving alumina disc. A comparative study of microstructure, hardness and wear of alloy and composite clads was made. The clad deposits were found sound and continuous. The hardness and wear resistance of the composites were markedly higher than that of the alloy clads. (author) 9 figs

Sex differences in Hadza dental wear patterns : a preliminary report.

Science.gov (United States)

Berbesque, J Colette; Marlowe, Frank W; Pawn, Ian; Thompson, Peter; Johnson, Guy; Mabulla, Audax

2012-09-01

Among hunter-gatherers, the sharing of male and female foods is often assumed to result in virtually the same diet for males and females. Although food sharing is widespread among the hunting and gathering Hadza of Tanzania, women were observed eating significantly more tubers than men. This study investigates the relationship between patterns of dental wear, diet, and extramasticatory use of teeth among the Hadza. Casts of the upper dentitions were made from molds taken from 126 adults and scored according to the Murphy dental attrition scoring system. Females had significantly greater anterior occlusal wear than males when we controlled for age. Males exhibited greater asymmetry in wear, with greater wear on the left side in canines, first premolars, and first molars. We suggest that these sex differences in wear patterns reflect the differences seen in the diet, as well as in the use of teeth as tools.

A coupled mechanical/hydrologic model for WIPP shaft seals

International Nuclear Information System (INIS)

Ehgartner, B.

1991-06-01

Effective sealing of the Waste Isolation Pilot Plant (WIPP) shafts will be required to isolate defense-generated transuranic wastes from the accessible environment. Shafts penetrate water-bearing hard rock formations before entering a massive creeping-salt formation (Salado) where the WIPP is located. Short and long-term seals are planned for the shafts. Short-term seals, a composite of concrete and bentonite, will primarily be located in the hard rock formations separating the water-bearing zones from the Salado Formation. These seals will limit water flow to the underlying long-term seals in the Salado. The long-term seals will consist of lengthly segments of initially unsaturated crushed salt. Creep closure of the shaft will consolidate unsaturated crushed salt, thereby reducing its permeability. However, water passing through the upper short-term seals and brine inherent to the salt host rock itself will eventually saturate the crushed salt and consolidation could be inhibited. Before saturating, portions of the crushed salt in the shafts are expected to consolidate to a permeability equivalent to the salt host rock, thereby effectively isolating the waste from the overlying water-bearing formations. A phenomenological model is developed for the coupled mechanical/hydrologic behavior of sealed WIPP shafts. The model couples creep closure of the shaft, crushed salt consolidation, and the associated reduction in permeability with Darcy's law for saturated fluid flow to predict the overall permeability of the shaft seal system with time. 17 refs., 6 figs., 1 tab

Turbine interstage seal with self-balancing capability

Science.gov (United States)

Mills, Jacob A; Jones, Russell B; Sexton, Thomas D

2017-09-26

An interstage seal for a turbine of a gas turbine engine, the interstage seal having a seal carrier with an axial extending seal tooth movable with a stator of the engine, and a rotor with a seal surface that forms the interstage seal with the seal tooth, where a magnetic force produced by two magnets and a gas force produced by a gas pressure acting on the seal carrier forms a balancing force to maintain a close clearance of the seal without the seal tooth contacting the rotor seal surfaces during engine operation. In other embodiments, two pairs of magnets produce first and second magnetic forces that balance the seal in the engine.

Enhanced sealing project (ESP): evolution of a full-sized concrete and bentonite shaft seal

International Nuclear Information System (INIS)

Dixon, D.A.; Priyanto, D.G.; Martino, J.B.; De Combarieu, M.; Johansson, R.; Korkeakoski, P.; Villagran, J.

2012-01-01

Document available in extended abstract form only. A full-scale shaft seal was designed and installed in the 5-m-diameter access shaft at Atomic Energy of Canada's (AECL's) Underground Research Laboratory (URL) at the point where he shaft intersects an ancient water-bearing, low-angle thrust fault in granitic rock. The seal, part of the permanent closure of the URL, consists of a 6-m-thick bentonite-based component sandwiched between 3-m-thick upper and lower, 3-m-thick concrete components. The bentonite-based component spans the fracture zone and extends approximately 1 m beyond the maximum identified extent of the fracture. This design was adopted in order to limit water from the deeper, saline regions mixing with the fresher, near-surface groundwater regime. The concrete components provide the mechanical confinement and an in situ compacted 40/60 mixture of bentonite clay and quartz sand provides the sealing component. Construction of the shaft seal was done as part of Canada's Nuclear Legacies Liability Program. However, monitoring the seal evolution was not part of the decommissioning program's mandate. In addition to accomplishing the permanent closure of the URL, this seal's construction provides a unique opportunity to instrument and monitor the evolution of a full-scale shaft seal as well as the recovery of the regional groundwater regime as the facility passively floods above the seal. A jointly funded monitoring project was developed by NWMO (Canada), SKB (Sweden), Posiva (Finland) and ANDRA (France) and since mid 2009 the thermal, hydraulic and mechanical evolution of the seal has been constantly monitored. The evolution of the type of seal being monitored in the ESP is of relevance to repository closure planning, gaining confidence in the functionality of shaft seals. Although constructed in a crystalline rock medium, the results of the ESP are expected to be relevant to the performance of seals in a variety of host rock types. The shaft seal has been

Sealing a conduit end

International Nuclear Information System (INIS)

Mentz, R.M.

1993-01-01

An apparatus for sealing or blocking conduits, such as the primary nozzles of a nuclear steam generator is described. It includes an annular bracket sealingly attached to the open end of the nozzle, the bracket having a plurality of threaded holes therein. Mounted atop the bracket is a generally circular nozzle dam for covering the opening. Interposed between the nozzle dam and the bracket is an extrusion-resistant seal member having a plurality of apertures therethrough for receiving each bolt. The seal member is configured to resist extrusion by having laminated layers of differing hardnesses, so that the seal member will not laterally extrude away from each bolt in a manner that enlarges the aperture surrounding each bolt as the nozzle dam is bolted to the bracket. (author)

Safe management of discussed sealed sources in Peru

International Nuclear Information System (INIS)

Mallaupoma, M.

2000-01-01

The future safe development of nuclear energy and progressive increasing use of sealed sources in medicine, research, industry and other fields in Peru, in the past years have determined the necessity to formulate and apply an Institutional policy to assure harmless and ecologically rational management of disused sealed sources in Peru. Some results of the studies, which served as a basis for design and construction of a facility for treatment, conditioning and storage of conditioned sealed sources are presented in this paper. The waste management system in Peru comprises operational and regulatory capabilities. Both of these activities are performed under a legislation. The Nuclear Research Center RACSO has a radioactive waste management department which is in charge of the management of disused sealed sources produced in the country. It is considered as a centralized waste processing and storage facility (WPSF). (author)

Hermetic Seal Leak Detection Apparatus

Science.gov (United States)

Kelley, Anthony R. (Inventor)

2013-01-01

The present invention is a hermetic seal leak detection apparatus, which can be used to test for hermetic seal leaks in instruments and containers. A vacuum tight chamber is created around the unit being tested to minimize gas space outside of the hermetic seal. A vacuum inducing device is then used to increase the gas chamber volume inside the device, so that a slight vacuum is pulled on the unit being tested. The pressure in the unit being tested will stabilize. If the stabilized pressure reads close to a known good seal calibration, there is not a leak in the seal. If the stabilized pressure reads closer to a known bad seal calibration value, there is a leak in the seal. The speed of the plunger can be varied and by evaluating the resulting pressure change rates and final values, the leak rate/size can be accurately calculated.

Friction and wear calculation methods

CERN Document Server

Kragelsky, I V; Kombalov, V S

1981-01-01

Friction and Wear: Calculation Methods provides an introduction to the main theories of a new branch of mechanics known as """"contact interaction of solids in relative motion."""" This branch is closely bound up with other sciences, especially physics and chemistry. The book analyzes the nature of friction and wear, and some theoretical relationships that link the characteristics of the processes and the properties of the contacting bodies essential for practical application of the theories in calculating friction forces and wear values. The effect of the environment on friction and wear is a

Wear of polymers and composites

CERN Document Server

Abdelbary, Ahmed

2015-01-01

In the field of tribology, the wear behaviour of polymers and composite materials is considered a highly non-linear phenomenon. Wear of Polymers and Composites introduces fundamentals of polymers and composites tribology. The book suggests a new approach to explore the effect of applied load and surface defects on the fatigue wear behaviour of polymers, using a new tribometer and thorough experiments. It discusses effects of surface cracks, under different static and cyclic loading parameters on wear, and presents an intelligent algorithm, in the form of a neural network, to map the relations

Lubricity Additives and Wear with DME in Diesel Injection Pumps

DEFF Research Database (Denmark)

Nielsen, Kasper; Sorenson, Spencer C.

1999-01-01

In recent years it has been demonstrated that Dimethyl Ether (DME) possess many characteristics that could make it a successful alternative to diesel in the next century. High wear of the fuel injection system has been reported. This is caused by lack of natural protective constituents of Dimethyl...... wear of standard diesel jerk pump plungers elements were made with weight measurements, diameter measurements, 2-D and 3-D surface roughness measurements, and photography by a Michelson interferometer. Several lubricity additives were tested, but none reduced wear levels to those for diesel fuel...

Advanced Seal Sessions I and II

Science.gov (United States)

Steinetz, Bruce M.; Dunlap, Patrick H.; Sarawate, Neelesh

2013-01-01

As aircraft operators continue to seek higher fuel efficiency, lower emissions, and longer on-wing performance, turbine engine designers are scrutinizing all components for areas of improvement. To achieve overall goals, turbine pressure ratios and by-pass ratios continue to climb. Also, designers are seeking to minimize parasitic and cooling flows to extract the most useful work out of the flow stream, placing a renewed interest on seal technology and secondary flow path management. In the area of future manned spacecraft, advancements are being examined for both habitat seals and re-entry thermal protection system thermal barrierseals. For long duration space craft, designers are continuing to look for savings in parasitic losses to reduce the amount of cabin re-supply air that needs to be brought along. This is placing greater demands on seal designs and materials to exhibit low leakage and be resistant to space environments. For future missions to and from distant planets, the re-entry heating will be higher than for low-earth orbit or lunar return motivating advanced thermal barrier development. This presentation will provide an overview of the seal challenges and opportunities in these diverse areas.

Reusable, tamper-indicating seal

International Nuclear Information System (INIS)

Ryan, M.J.

1978-01-01

A reusable, tamper-indicating seal is comprised of a drum confined within a fixed body and rotatable in one direction therewithin, the top of the drum constituting a tray carrying a large number of small balls of several different colors. The fixed body contains parallel holes for looping a seal wire therethrough. The base of the drums carries cams adapted to coact with cam followers to lock the wire within the seal at one angular position of the drum. A channel in the fixed body, visible from outside the seal, adjacent the tray constitutes a segregated location for a small plurality of the colored balls. A spring in the tray forces colored balls into the segregated location at one angular position of the drum, further rotation securing the balls in position and the wires in the seal. A wedge-shaped plough removes the balls from the segregated location, at a different angular position of the drum, the wire being unlocked at the same postion. A new pattern of colored balls will appear in the segregated location when the seal is relocked

Determination of rail wear and short-time wear measurements of rails applying radioisotopes

International Nuclear Information System (INIS)

Grohmann, H.D.

1981-01-01

An energetic model has been developed for calculating rail wear. Short-time wear tests on rails after surface activation and following activity measurements showed a good agreement with the calculated values

New oil condition monitoring system, Wearsens® enables continuous, online detection of critical operating conditions and wear damage

Directory of Open Access Journals (Sweden)

Manfred Mauntz

2015-12-01

Full Text Available A new oil sensor system is presented for the continuous, online measurement of the wear in turbines, industrial gears, generators, hydraulic systems and transformers. Detection of change is much earlier than existing technologies such as particle counting, vibration measurement or recording temperature. Thus targeted, corrective procedures and/or maintenance can be carried out before actual damage occurs. Efficient machine utilization, accurately timed preventive maintenance, increased service life and a reduction of downtime can all be achieved. The presented sensor system effectively controls the proper operation conditions of bearings and cogwheels in gears. The online diagnostics system measures components of the specific complex impedance of oils. For instance, metal abrasion due to wear debris, broken oil molecules, forming acids or oil soaps, result in an increase of the electrical conductivity, which directly correlates with the degree of contamination of the oil. For additivated lubricants, the stage of degradation of the additives can also be derived from changes in the dielectric constant. The determination of impurities or reduction in the quality of the oil and the quasi continuous evaluation of wear and chemical aging follow the holistic approach of a real-time monitoring of an alteration in the condition of the oil-machine system. Once the oil condition monitoring sensors are installed on the wind turbine, industrial gearbox and test stands, the measuring data can be displayed and evaluated elsewhere. The signals are transmitted to a web-based condition monitoring system via LAN, WLAN or serial interfaces of the sensor unit. Monitoring of the damage mechanisms during proper operation below the tolerance limits of the components enables specific preventive maintenance independent of rigid inspection intervals.

Critical component wear in heavy duty engines

CERN Document Server

Lakshminarayanan, P A

2011-01-01

The critical parts of a heavy duty engine are theoretically designed for infinite life without mechanical fatigue failure. Yet the life of an engine is in reality determined by wear of the critical parts. Even if an engine is designed and built to have normal wear life, abnormal wear takes place either due to special working conditions or increased loading.  Understanding abnormal and normal wear enables the engineer to control the external conditions leading to premature wear, or to design the critical parts that have longer wear life and hence lower costs. The literature on wear phenomenon r

Double angle seal forming lubricant film

Science.gov (United States)

Ernst, William D.

1984-01-01

A lubricated piston rod seal which inhibits gas leaking from a high pressure chamber on one side of the seal to a low pressure chamber on the other side of the seal. A liquid is supplied to the surface of the piston rod on the low pressure side of the seal. This liquid acts as lubricant for the seal and provides cooling for the rod. The seal, which can be a plastic, elastomer or other material with low elastic modulus, is designed to positively pump lubricant through the piston rod/seal interface in both directions when the piston rod is reciprocating. The capacity of the seal to pump lubricant from the low pressure side to the high pressure side is less than its capacity to pump lubricant from the high pressure side to the low pressure side which ensures that there is zero net flow of lubricant to the high pressure side of the seal. The film of lubricant between the seal and the rod minimizes any sliding contact and prevents the leakage of gas. Under static conditions gas leakage is prevented by direct contact between the seal and the rod.

To the question of modeling of wheels and rails wear processes

Directory of Open Access Journals (Sweden)

S.V. Myamlin

2013-06-01

Full Text Available Purpose. There is a need of wear process modeling in the wheel-rail system. This is related to the fact that the wear processes in this system are absolutely different in the initial and final stages. The profile change of rail and, especially, of the wheels caused by the wear significantly affects the rolling stock dynamics, traffic safety and the resource of the wheels and rails. Wear modeling and the traffic safety evaluation requires the accounting of the low frequency component forces (including the modeling of transitional areas affecting the wheel on the side of the rail and carriage in motion of rolling stock, so the statistical analysis is not possible. Methodology. The method of mathematical modeling of the wheel set and the rail interaction was used during the research conducting. Findings. As a result of the modeling of the wheel set motion on the rail track, the mathematic model with 19 freedom degrees was obtained. This model takes into account the axle torque and studies wheels constructions as the components of the mechanical systems, consisting of a hub and tire. Originality. The mathematic model allows evaluating the wear degree of the wheels and rails when using on the rolling stock not only all-metal wheel sets, but also compound ones with the use of spring wheels and independent rotation of semi-axes with the wheels. Practical value. The development of the improved mathematical model of freight car wheel set motion with differential rotation of the wheels and compound axles allows studying the wear processes of wheels and rails.

Reciprocating piston pump system with screw drive

Science.gov (United States)

Perkins, Gerald S. (Inventor); Moore, Nicholas R. (Inventor)

1981-01-01

A pump system of the reciprocating piston type is described, which facilitates direct motor drive and cylinder sealing. A threaded middle potion of the piston is engaged by a nut connected to rotate with the rotor of an electric motor, in a manner that minimizes loading on the rotor by the use of a coupling that transmits torque to the nut but permits it to shift axially and radially with respect to the rotor. The nut has a threaded hydrostatic bearing for engaging the threaded piston portion, with an oil-carrying groove in the nut being interrupted. A fluid emitting seal located at the entrance to each cylinder, can serve to center the piston within the cylinder, wash the piston, and to aid in sealing. The piston can have a long stroke to diameter ratio to minimize reciprocations and wear on valves at high pressures. The voltage applied to the motor can be reversed prior to the piston reaching the end of its stroke, to permit pressure on the piston to aid in reversing the motor.

Shaft and tunnel sealing considerations

International Nuclear Information System (INIS)

Kelsall, P.C.; Shukla, D.K.

1980-01-01

Much of the emphasis of previous repository sealing research has been placed on plugging small diameter boreholes. It is increasingly evident that equal emphasis should now be given to shafts and tunnels which constitute more significant pathways between a repository and the biosphere. The paper discusses differences in requirements for sealing shafts and tunnels as compared with boreholes and the implications for seal design. Consideration is given to a design approach for shaft and tunnel seals based on a multiple component design concept, taking into account the requirements for retrievability of the waste. A work plan is developed for the future studies required to advance shaft and tunnel sealing technology to a level comparable with the existing technology for borehole sealing

Rotatable seal assembly

International Nuclear Information System (INIS)

Garibaldi, J.L.; Logan, C.M.

1982-01-01

An assembly is provided for rotatably supporting a rotor on a stator so that vacuum chambers in the rotor and stator remain in communication while the chambers are sealed from ambient air, which enables the use of a ball bearing or the like to support most of the weight of the rotor. The apparatus includes a seal device mounted on the rotor to rotate therewith, but shiftable in position on the rotor while being sealed to the rotor as by an oring. The seal device has a flat face that is biased towards a flat face on the stator, and pressurized air is pumped between the faces to prevent contact between them while spacing them a small distance apart to avoid the inflow of large amounts of air between the faces and into the vacuum chambers

A new methodology for predictive tool wear

Science.gov (United States)

Kim, Won-Sik

An empirical approach to tool wear, which requires a series of machining tests for each combination of insert and work material, has been a standard practice for industries since early part of the twentieth century. With many varieties of inserts and work materials available for machining, the empirical approach is too experiment-intensive that the demand for the development of a model-based approach is increasing. With a model-based approach, the developed wear equation can be extended without additional machining experiments. The main idea is that the temperatures on the primary wear areas are increasing such that the physical properties of the tool material degrade substantially and consequently tool wear increases. Dissolution and abrasion are identified to be the main mechanisms for tool wear. Flank wear is predominantly a phenomenon of abrasion as evident by the presence of a scoring mark on the flank surface. Based on this statement, it is reasonable to expect that the flank-wear rate would increase with the content of hard inclusions. However, experimental flank wear results did not necessary correspond to the content of cementite phase present in the steels. Hence, other phenomena are believed to significantly affect wear behavior under certain conditions. When the cutting temperature in the flank interface is subjected to high enough temperatures, pearlitic structure austenizes. During the formation of a new austenitic phase, the existing carbon is dissolved into the ferrite matrix, which will reduce the abrasive action. To verify the austenitic transformation, turning tests were conducted with plain carbon steels. The machined surface areas are imaged using X-ray diffraction the Scanning Electron Microscope (SEM) and the Transmission Electron Microscope (TEM). On the other hand, crater wear occurs as a result of dissolution wear and abrasive wear. To verify the wear mechanisms of crater wear, various coating inserts as well as uncoated inserts were

Wear and Degradation Modes in Selected Vehicle Tribosystems

OpenAIRE

G. Pantazopoulos; A. Tsolakis; P. Psyllaki; A. Vazdirvanidis

2015-01-01

The wear and degradation mechanisms of two principle vehicle tribosystems are presented to elucidate the main causes of their premature failure. The first case study concerns the malfunction of an automotive cast iron pressure plate operated in an automobile clutch system. The second is related to the unexpected failure of a stainless steel brake disk of a high performance motorcycle. Both components are designed to function under sliding friction conditions that lead to the severe wear of co...

Recent advances in magnetic liquid sealing

International Nuclear Information System (INIS)

Raj, K.; Stahl, P.; Bottenberg, W.; True, D.; Martis, G.; Zook, C.

1979-01-01

In this paper recent work in design and testing of two special magnetic liquid seals extending the state-of-the-art of ferrofluidic sealing is discussed. These custom seals are a moving belt edge seal and an exclusion seal. The first seal provides a hermetic barrier to solid particulates expected to be present in enclosed nuclear environments. The second seal is used on a magnetic disk drive spindle and reduces the particulate contaminants in the memory disk pack area by up to three orders of magnitude. In addition, bearing life in the spindle is found to be doubled due to reduction of operating temperature. The fundamentals of magnetic fluid sealing are presented in terms of magnetic circuit design and physical properties of ferrofluids

Elastomers in Combined Rolling-Sliding Contact; Wear and its Underlying Mechanisms

Science.gov (United States)

Rowe, Kyle Gene

Elastomeric materials, specifically rubbers, being both of a practical and scientific importance, have been the subjects of vast amounts of research spanning well over two centuries. There is currently a large effort by tire manufacturers to design new rubber compounds with lower rolling resistance, higher sliding friction, and reduced or predictable wear. At present, these efforts are primarily based on a few empirical rules and very costly trial and error testing; only a basic understanding of the mechanisms involved in the wear of elastomeric materials exists despite rigorous study. In general, the only well controlled experiments have been for simple loading and sliding schemes. The aim of this work is to characterize the tribological properties of a carbon black filled natural rubber sample. This work explores (1) its behavior in unidirectional sliding, (2) contact mechanics, (3) traction properties in combined rolling and sliding, (4) frictional heating response, and (5) wear. It was found that the friction coefficient of this material was dependent upon sliding velocity, contact pressure, and surface roughness. The high friction coefficients also lead to a bifurcation of the contact area into two different pressure regimes at sliding velocities greater than 10 mm/s . The traction response of this material in combined rolling and sliding exhibited similar behavior, being a function of the contact pressure, but not rolling velocity. The wear of this material was found to be linearly dependent upon the global slip condition and occurred preferentially on the sample. Investigations of the worn surface revealed that the most likely mechanism of wear is the degradation of surface material in a confined layer a few micrometers thick. A simple spring-mass model was developed to offer an explanation of localized wear. It was found that the coupling of system elements in the normal direction helped to shift the load from wearing elements to non-wearing ones. The

Design of analytical instrumentation with D-T sealed neutron generators

International Nuclear Information System (INIS)

Qiao Yahua; Wu Jizong; Zheng Weiming; Liu Quanwei; Zhang Min

2008-01-01

Analytical instrumentation with D-T sealed neutron generators source activation, The 14 MeV D-T sealed neutron tube with 10 9 n · s -1 neutron yield is used as generator source. The optimal structure of moderator and shield was achieved by MC computing.The instrumentation's configuration is showed. The instrumentation is made up of the SMY-DT50.8-2.1 sealed neutron tube and the high-voltage power supply system, which center is the sealed neutron generators. 6 cm Pb and 20 cm polythene is chosen as moderator, Pb, polythene and 10 cm boron-PE was chosen as shield .The sample box is far the source from 9 cm, the measurement system were made up of HPGe detector and the sample transforming system. After moderator and shield, the thermal neutron fluence rate at the point of sample is 0.93 × 10 6 n · s -1 cm -2 , which is accorded with design demand, and the laboratory and surroundings reaches the safety standard of the dose levels. (authors)

SEALING SIMULATED LEAKS

Energy Technology Data Exchange (ETDEWEB)

Michael A. Romano

2004-09-01

This report details the testing equipment, procedures and results performed under Task 7.2 Sealing Simulated Leaks. In terms of our ability to seal leaks identified in the technical topical report, Analysis of Current Field Data, we were 100% successful. In regards to maintaining seal integrity after pigging operations we achieved varying degrees of success. Internal Corrosion defects proved to be the most resistant to the effects of pigging while External Corrosion proved to be the least resistant. Overall, with limitations, pressure activated sealant technology would be a viable option under the right circumstances.

Fog seal guidelines.

Science.gov (United States)

2003-10-01

Fog seals are a method of adding asphalt to an existing pavement surface to improve sealing or waterproofing, prevent further stone loss by holding aggregate in place, or simply improve the surface appearance. However, inappropriate use can result in...

Wear mechanisms in ceramic hip implants.

Science.gov (United States)

Slonaker, Matthew; Goswami, Tarun

2004-01-01

The wear in hip implants is one of the main causes for premature hip replacements. The wear affects the potential life of the prosthesis and subsequent removals of in vivo implants. Therefore, the objective of this article is to review various joints that show lower wear rates and consequently higher life. Ceramics are used in hip implants and have been found to produce lower wear rates. This article discusses the advantages and disadvantages of ceramics compared to other implant materials. Different types of ceramics that are being used are reviewed in terms of the wear characteristics, debris released, and their size together with other biological factors. In general, the wear rates in ceramics were lower than that of metal-on-metal and metal-on-polyethylene combinations.

Microstructure and lubricating property of ultra-fast laser pulse textured silicon carbide seals

Science.gov (United States)

Chen, Chien-Yu; Chung, Chung-Jen; Wu, Bo-Hsiung; Li, Wang-Long; Chien, Chih-Wei; Wu, Ping-Han; Cheng, Chung-Wei

2012-05-01

Most previous studies have employed surface patterning to improve the performance of lubrication systems. However, few have experimentally analyzed improved effects on friction reduction in SiC mechanical seals by ultra-fast laser pulse texturing. This work applies surface texturing on a non-contact mechanical seal and analyzes the characteristics of the resultant surface morphology. A femtosecond laser system is employed to fabricate micro/nanostructures on the SiC mechanical seal, and generates microscale-depth stripes and induces nanostructures on the seal surface. This work examines the morphology and cross section of the SiC nanostructures that correspond to the different scanning speeds of the laser pulse. Results show that varying the scanning speed enables the application of nanostructures of different amplitudes and widths on the surface of the seal. The friction coefficient of the introduced SiC full-textured seal is about 20% smaller than that of a conventional SiC mechanical seal. Hence, femtosecond laser texturing is effective and enables direct fabrication of the surface micro/nanostructures of SiC seals. This technique also serves as a potential approach to lubricating applications.

Microstructure and lubricating property of ultra-fast laser pulse textured silicon carbide seals

Energy Technology Data Exchange (ETDEWEB)

Chen, Chien-Yu.; Li, Wang-Long [National Cheng Kung University, Department of Materials Science and Engineering, Tainan, Taiwan (China); Chung, Chung-Jen; Wu, Bo-Hsiung [National Cheng Kung University, Center for Micro/Nano Science and Technology, Tainan, Taiwan (China); Chien, Chih-Wei; Wu, Ping-Han; Cheng, Chung-Wei [ITRI South, Industrial Technology, Research Institute, Laser Application Technology Center, Tainan, Taiwan (China)

2012-05-15

Most previous studies have employed surface patterning to improve the performance of lubrication systems. However, few have experimentally analyzed improved effects on friction reduction in SiC mechanical seals by ultra-fast laser pulse texturing. This work applies surface texturing on a non-contact mechanical seal and analyzes the characteristics of the resultant surface morphology. A femtosecond laser system is employed to fabricate micro/nanostructures on the SiC mechanical seal, and generates microscale-depth stripes and induces nanostructures on the seal surface. This work examines the morphology and cross section of the SiC nanostructures that correspond to the different scanning speeds of the laser pulse. Results show that varying the scanning speed enables the application of nanostructures of different amplitudes and widths on the surface of the seal. The friction coefficient of the introduced SiC full-textured seal is about 20% smaller than that of a conventional SiC mechanical seal. Hence, femtosecond laser texturing is effective and enables direct fabrication of the surface micro/nanostructures of SiC seals. This technique also serves as a potential approach to lubricating applications. (orig.)

Wear of control rod cluster assemblies and of instrumentation thimbles: first results obtained with the vibrateau wear simulator