Leakage and friction measurements on reciprocating square-section seals.

by B. S. Nau

Publisher: British Hydromechanics Research Association in [s.l.]

Written in English
Published: Downloads: 867
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Edition Notes

SeriesBHRA research report -- 938
ID Numbers
Open LibraryOL13840809M

leakage. This radial load has to produce a contact pressure on the shaft or stem and bore high enough to overcome the process fl uid pressure. The equipment shaft, spindle or stem drive mechanism has to readily overcome static and dynamic or running friction during operation. High packing friction can impede the equipment per-. Drivetrain low friction seals made from PTFE material compounds are particularly beneficial in automotive design and becoming instrumental in equipment design, as new applications require greater endurance to extremely harsh chemicals, high surface speeds, high temperatures, and dry running conditions. The demand for better fuel mileage requires reduced friction and torque to rotate in all. This patent describes an engine having a reciprocating piston axially stroking within a walled cylinder by a pressure differential acting on opposite axial sides of the piston and an annular piston ring disposed in an annular piston ring groove around the piston for sealing between the piston and the wall of the cylinder to resist leakage past the piston. liquid friction (a lubrication film of fluid between seal and dynamic surface) At start up, the friction is high because it must get over the static friction coefficient [area 1]. Then, when the speed increases, a film of fluid interposes between seal and dynamic surface reducing the touching surface and thus the friction .

Z-Seal U-Cups Z-seals are squeeze type seals, primarily used for heavy-duty rod applications. Z-seals have excellent sealability, low compression set and superior anti-extrusion characteristics when compared to other lip seals. Under low-pressure conditions, the sealing lip provides its own compressive sealing force. Z-Seal U-Cup Design. Sterling Seal & Supply Buna/NBR "x" profile, commonly called quad O-Rings can be used in a wide variety of static and dynamic sealing applications They offer twice the sealing surface in Comparison to a standard O-Ring and require less squeeze to maintain an effective seal This reduction in squeeze means less friction and improved seal life Additionally, parting lines are between the lobes. Saves space, reduces cost – One Multiseal® low friction seal can replace two U-Cups in many applications. Less force, better seal – Lower breakaway force and reduced operating pressures make them ideal in reciprocating applications. The right fit – Multiseal® low friction seals will fit . There were of course important publications in this field even before A notable example is the seminal work of my predecessor at BHRA, Dr D. F. Denny, whose researches on reciprocating fluid power seals, "The sealing mechanism of flexible packings", was published in by a long since defunct government department, the Ministry of Supply.

The micro-leakage testing machine (SMLA) developed by the authors was used to measure micro-leakage at high precision and in a short time [2]. The results showed that the sealing phenomena were related to the ratio of seal surface contact pressure Ps / elastic modulus of seal E, determined by the compression ratio of seals, and does not depend.   New DEMETRA machine, to measure the outgassing of the lubricants, polymeric materials, and coatings that need to work under vacuum conditions (ASTM E , ECSS-Q-STC). New drag friction tester to measure drag friction for different applications (e.g., paints in the ships, friction losses in heat exchangers). The seals can be made perfectly leak-proof for cases of static pistons and cylinders for fl uid pressures up to psi. (Limit of test pressure). The pressure may be constant or variable. B. The seals can be made to seal satisfactorily between reciprocating pistons and cylinders at .

Leakage and friction measurements on reciprocating square-section seals. by B. S. Nau Download PDF EPUB FB2

Reciprocating seals Literature review Introduetion Friction and leakage measurements Static contact situation Experimental work Theoretica.

work Tribology of the seal contact Experimental work Theoretica. work Cited by: This paper deals with the problem of calculating oil film thicknesses, oil leakage, and friction forces in seal situations like those occurring in hydraulic cylinders.

A general scheme for the analysis is presented, covering both piston seals and piston rod by:   The seal model is used to predict leakage rate, friction force, fluid and contact pressure distributions, and film thickness distribution.

Results for a typical seal show that the seal operates with mixed lubrication, and the seal roughness plays an important role in determining whether or not the seal Cited by:   Friction measurements of reciprocating G. Rese arch on tribology of hydraulic reciprocating seals.

Chapter in the book titled the study included the calculation of seal leakage. 69 Paper Ill(iii) Lubricationof reciprocating seals: Experiments on the influence of surface roughness on friction and leakage A.

s and M. Visscher In the past, most theoretical work on reciprocating seals has been dedicated to the solution of the elastohydrodynamic lubrication (EHL) problem for smooth by: Leakage and friction characteristics of some single-lip U-seals fitted to reciprocating shafts 8pp.

16 figs. (Aug. ) RR D.F. Denny Some measurement of fluid pressures between plane parallel thrust surfaces with special reference to radial-face seals 11pp. 18 figs. (Jan. The efficiency-reinforcement design framework of hydraulic reciprocating sealing driven by ideal solution is proposed.

The seals’ main operating characteristics, seal efficiency control, leakage. Friction is one of the most common and underestimated causes of rod seal leakage in a hydraulic system.

However, measuring and addressing it can be a challenge because it requires skillful balance. Too much friction will cause excessive seal wear, reduced seal life, and diminished hydraulic system efficiency, while too little or insufficient.

Seal-leakage problems are normally investigated through experiments and numerical simulations. 9–12 9. and S. Fu, “ Numerical analysis of leakage of elastomeric seals for reciprocating circular motion,” Tribology Internatio 21 Persson, “ Theory of rubber friction and contact mechanics,” J.

Chem. Phys.(). • Reduced leakage. • Low-friction operation. • Long trouble-free working life. reciprocating rod or ram. Piston seals — to seal between the reciprocating piston and cylinder bore.

required housing measurements, then check the standard listings charts for the. Non-linear friction in reciprocating hydraulic rod seals: Simulation and measurement.

A K Bullock 1, D G Tilley 1, D N Johnston 1, C R Bowen 1 and P S Keogh 1. Published under licence by IOP Publishing Ltd. Reciprocating rod seals are widely used in the hydraulic actuator to prevent the leakage of fluid.

The sealing lip profile changes with the seal wear, resulting in an increase in the leakage. A texturing rod changes the lubrication characteristics of the seal, so it affects the wear and leakage of the seal.

Critical to the reliability of any reciprocating seal system is the surface condition of the dynamic interface. Reciprocating seals are called “self-acting” as the design allows maximum contact pressures between the seal and housing walls, meaning they always exceed the inner and outer seal diameter, so no leakage can occur.

The instrument [as shown in Figs. 1(a) and 1(b)] is designed to mimic dynamic sliding friction under a high pressure hydrogen environment as might be experienced by a polymer sliding seal in a compressor piston or a mechanical valve with an O-ring seal.

The system is configured for linear reciprocating motion of a steel ball or pin across the. Kanters AFC, Visscher M. Lubrication of reciprocating seals: experiments on the influence of surface roughness on friction and leakage. In: Proceedings of the 15th Leeds–Lyon symposium on tribology, p.

69– Hydrodynamics of rubber seals for reciprocating motion, lubricating film thickness, and outleakage of O-seals. Artur Karaszkiewicz; The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Study of leakage and friction of flexible seals for steady motion via a numerical.

A reciprocating compressor is a fairly simple machine and easy to understand the basic mechanics. This tutorial focuses on what occurs in the compression chamber of a compressor cylinder, and more specifically on the P-V diagram (Figure 1).

Materials have a great impact on friction. Changing the material of the seal will also change the sealing characteristics.

A rubber or urethane style seal often results in a zero-leak seal with very high friction. At the same time, using a highly-filled PTFE seal will often result in a very low friction seal that may have a small amount of seepage. Youssef Bahi (ENSAM/UMI) reasoned over the complexity of decreasing both leakage and friction of seals at the same time.

The first one demands for a lower gap height while the second requires a thicker lubricant film and a greater hydrodynamic pressure build-up.

He presented a complete quasi-static model of a reciprocating U-cup seal. Study of leakage and friction of flexible seals for steady motion via a numerical approximation method. Tribology International39 (9), DOI: /nt George K.

Nikas, Richard S. Sayles. Computational model of tandem rectangular elastomeric seals for reciprocating motion. Shaft seals are used on rotating, reciprocating, and oscillating shafts to contain oil and grease and exclude contaminants.

Known as oil or radial lip seals, shaft seals can also contain pressure. cycling and the seal starts to leak. For extrusion and direction of pressure information for static seals see fig. In a reciprocating application the tendency for extrusion will increase if friction and system pressure act on the O-ring in the same direction.

Groove design can reduce the tendency for extrusion. See figures a & b. leakage. Leakage can be avoided by surface patterning on the elastomeric seal (which may be formed during the production or operation) but in some seals, such as reciprocating seals, the leakage can be prevented by increasing the contact pressure and decreasing the lubrication film thickness.

In such situations there exists a high risk of. prescribed text books. The information presented here is merely a collection by the Measurement of friction power (Willian‟s line method, Morse test, Motoring test) 23 Lecture Fuel consumption measurements (volumetric and gravimetric method), air which provides air tight seal to prevent leakage of the burnt gases into the lower.

of reciprocating seals over the past four decades. Some key experimental observations, and how they assisted developments that have led to the seals we have today, are discussed, together with examples of how seal design has progressed and performance improved.

Detailed numerical analysis has lagged behind empirical development until very recently. Assembly and dismantling of seals 7. Methods of measurement and measuring apparatus Seal leakage Seal friction Pressure measurement Surface roughness Temperature measurement 8.

Calibration 9. Test procedure Test programme Repeat series Presentation of. The friction forces of the seals were measured at −40 to °C. The O-ring made from rubber material with lower rubber hardness and lower TR10 reduced the friction force.

The friction force of Oval-ring was decreased in comparison with those of O-ring and D-ring. Results show that the rectangular seals perform best in fluid leakage, and O-ring seals are better in reducing the friction force.

The oil leakages of the seals increase with the speed while the seawater leakages remain roughly constant. And the oil leakages of all the seals are larger than the seawater leakage.

Types of seal rings, fluid. This paper provides the experimental results that will be used to validate an extension of the Persson model to Hertzian contact seals.

A set of samples for leakage experiments was produced with varying surface topology. The surface roughness of these samples is measured and the leakage behaviour under high pressure is evaluated.

Friction torque and seal temperature measurement. Seal friction measurements are performed on a specialized SKF test rig (Fig.6). The shaft is driven by an electrical motor al - lowing a very wide, programmable, range of rotational speed.

The central part of the test rig is the air bearing spindle, onto. O-rings, chevron seals, cup packings, metal bellows and other conventional seals. At that time, Bellofram initiated what proved to be a five-year program of intensive research and development, to produce a frictionless and leak-proof rolling seal that would handle pressures, temperatures and stroke lengths over an extremely wide range.A lip seal is a circular sealing element encompassing either a rotating or reciprocating shaft.

The lip seal excludes or includes (seals) a medium in one defined volume away from another, where leakage would be a product failure.

Lip seals utilize polymeric (elastomeric or .Sealing Performance of Lip Type Seals for Rotary Shaft and Reciprocating Shaft under Low Temperature Condition For either case for rotary shaft or reciprocating shaft motion, rubber lip type seal leakage problems are often encountered under low temperature conditions.