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Article
Publication date: 1 June 1975

B.S. NAU

FLUID SEALING research at BHRA Fluid Engineering has its roots in the early years following the 1939–45 war. In 1945 the then Ministry of Aircraft Production felt that the…

40

Abstract

FLUID SEALING research at BHRA Fluid Engineering has its roots in the early years following the 1939–45 war. In 1945 the then Ministry of Aircraft Production felt that the equipment designer needed sound, basic information on the way hydraulic jack seals functioned and the factors affecting their performance. D. F. Denny was therefore seconded to Imperial College, London, to undertaken programme of research on reciprocating oil seals, which resulted in the publication of a 120‐page volume: “The sealing mechanism of flexible packings”, recently reprinted to meet a continuing demand.

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Industrial Lubrication and Tribology, vol. 27 no. 6
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 1 April 1995

Bill Wilson

Summarizes briefly the dramatic advances made in the reliability of mechanical seals for rotating shafts in the process chemical and petrochemical industries over the last 30…

1190

Abstract

Summarizes briefly the dramatic advances made in the reliability of mechanical seals for rotating shafts in the process chemical and petrochemical industries over the last 30 years. Shows that expected mean time before failure has improved from tens of days to years over that time.

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Industrial Lubrication and Tribology, vol. 47 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

Available. Open Access. Open Access
Article
Publication date: 13 May 2022

Gabriel Dämmer, Hartmut Bauer, Rüdiger Neumann and Zoltan Major

This study aims to investigate the suitability of a multi-step prototyping strategy for producing pneumatic rotary vane actuators (RVAs) for the development of lightweight robots…

1428

Abstract

Purpose

This study aims to investigate the suitability of a multi-step prototyping strategy for producing pneumatic rotary vane actuators (RVAs) for the development of lightweight robots and actuation systems.

Design/methodology/approach

RVAs typically have cast aluminum housings and injection-molded seals that consist of hard thermoplastic cores and soft elastomeric overmolds. Using a combination of additive manufacturing (AM), computer numerical control (CNC) machining and elastomer molding, a conventionally manufactured standard RVA was replicated. The standard housing design was modified, and polymeric replicas were obtained by selective laser sintering (SLS) or PolyJet (PJ) printing and subsequent CNC milling. Using laser-sintered molds, actuator seals were replicated by overmolding laser-sintered polyamide cores with silicone (SIL) and polyurethane (PU) elastomers. The replica RVAs were subjected to a series of leakage, friction and durability experiments.

Findings

The AM-based prototyping strategy described is suitable for producing functional and reliable RVAs for research and product development. In a representative durability experiment, the RVAs in this study endured between 40,000 and 1,000,000 load cycles. Frictional torques were around 0.5 Nm, which is 10% of the theoretical torque at 6 bar and comparable to that of the standard RVA. Models and parameters are provided for describing the velocity-dependent frictional torque. Leakage experiments at 10,000 load cycles and 6 bar differential pressure showed that PJ housings exhibit lower leakage values (6.8 L/min) than laser-sintered housings (15.2 L/min), and PU seals exhibit lower values (8.0 l/min) than SIL seals (14.0 L/min). Combining PU seals with PJ housings led to an initial leakage of 0.4 L/min, which increased to only 1.2 L/min after 10,000 load cycles. Overall, the PU material used was more difficult to process but also more abrasion- and tear-resistant than the SIL elastomer.

Research limitations/implications

More work is needed to understand individual cause–effect relationships between specific design features and system behavior.

Originality/value

To date, pneumatic RVAs have been manufactured by large-scale production technologies. The absence of suitable prototyping strategies has limited the available range to fixed sizes and has thus complicated the use of RVAs in research and product development. This paper proves that functional pneumatic RVAs can be produced by using more accessible manufacturing technologies and provides the tools for prototyping of application-specific RVAs.

Details

Rapid Prototyping Journal, vol. 28 no. 11
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 19 May 2021

Hua-Lin Yang, Xiulong Li, Weiwei Sun, Fang Deng and Jie Du

This paper aims to present the mixed elastohydrodynamic lubrication (EHL) model and obtain the leakage characteristics for the skeleton reciprocating oil seal.

177

Abstract

Purpose

This paper aims to present the mixed elastohydrodynamic lubrication (EHL) model and obtain the leakage characteristics for the skeleton reciprocating oil seal.

Design/methodology/approach

The model consists of a finite element analysis of the contact pressure, a fluid mechanics analysis of the fluid film, a contact analysis of the asperity contact pressure, a deformation analysis of the seal lip and an iterative numerical simulation process.

Findings

Simulation results show that the leakage is in direct proportion to the seal roughness and speed, and in inverse proportion to the fluid viscosity. Comparisons with the experimental results verify the validity of the mixed EHL model.

Originality/value

This study provides a helpful method to calculate the leakage of the skeleton reciprocating oil seal, which shortens its development cycles.

Details

Industrial Lubrication and Tribology, vol. 73 no. 4
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 27 January 2022

Zhen-Tao Li, Yangli Zhou, Xiaoli Yin, Muming Hao, Dechao Meng and Baojie Ren

The purpose of this paper is to investigate the effects of surface topography, including surface roughness, waviness and taper, on the cavitation of liquid film lubricated…

239

Abstract

Purpose

The purpose of this paper is to investigate the effects of surface topography, including surface roughness, waviness and taper, on the cavitation of liquid film lubricated mechanical seals (LFL-MS).

Design/methodology/approach

A universal governing equation considering cavitation is established, and an equivalent relative density is defined to characterize the cavitation degree. The equation is discretized by the finite volume method and solved by the Gauss–Seidel relaxation scheme.

Findings

Results indicate that both radial length and a circumferential width of the cavitation zone and cavitation degree are affected significantly by the waviness amplitude and taper, but the effect of surface roughness is limited.

Originality/value

Effect mechanism of surface topography on the cavitation of LFL-MS is investigated and cavitation degree is reflected by an equivalent relative density. The results further help to comprehensively explore the cavitation mechanism.

Details

Industrial Lubrication and Tribology, vol. 74 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 8 October 2024

Liming Teng, Jinbo Jiang, Xudong Peng, Fan Wu and Wenjing Zhao

This study aims to understand how the assembly of rotating ring affects the axial forced vibration of gas face seals.

26

Abstract

Purpose

This study aims to understand how the assembly of rotating ring affects the axial forced vibration of gas face seals.

Design/methodology/approach

A three-mass kinematic model is established to investigate the axial movement of the rotating ring with bilateral constraints. The separation, collision and frictional sliding of the rotating ring in sleeve are discussed under rotor excitation. The effects of operating parameters and O-ring dynamic characteristics on the separation degree and film thickness disturbance are analyzed. A dimensionless axial characteristic force is defined to determine the critical conditions for the occurrence of separation. Several effective methods to eliminate the separation are proposed based on the adjustment of typical installation parameters.

Findings

Under rotor excitation, there may be two collisions between the rotating ring and the sleeve surfaces in one excitation period. This will cause self-excited vibration of the fluid film, increasing the risk of seal failure. The separation and collision can be prevented by increasing the equilibrium ratio, the installation radius of the O-ring on the outer surface of the rotating ring and the friction in the sleeve.

Originality/value

The results develop the modeling of multibody dynamics of gas face seals, enabling more accurate prediction of vibration characteristics.

Details

Industrial Lubrication and Tribology, vol. 76 no. 10
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 1 March 1979

B.J. ROYLANCE

In his introduction to this paper the author likened the function of the tribology centres to that of a two‐way bridge—for the drawing in of information about industry's

38

Abstract

In his introduction to this paper the author likened the function of the tribology centres to that of a two‐way bridge—for the drawing in of information about industry's tribological problems and for the outflow of remedial advice and help.

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Industrial Lubrication and Tribology, vol. 31 no. 3
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 1 February 1985

S. Alliney, A. Strozzi and A. Tralli

A finite element model for the elastohydrodynamic lubrication problem is presented. A coupling between the hydrodynamic equation and the foundation compliance equation is…

49

Abstract

A finite element model for the elastohydrodynamic lubrication problem is presented. A coupling between the hydrodynamic equation and the foundation compliance equation is performed, then the resulting functional problem is given an ‘extended’ variational formulation. Some preliminary numerical results are also presented.

Details

Engineering Computations, vol. 2 no. 2
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 February 1993

D. Zeus

Cavitation damage in the form of spongy, pitted surfaces is widely associated with pump impellers, marine propellers and sliding bearings. It used to be rare as a form of damage…

87

Abstract

Cavitation damage in the form of spongy, pitted surfaces is widely associated with pump impellers, marine propellers and sliding bearings. It used to be rare as a form of damage on mechanical seals, but the number of cases has been increasing in the last few years. This is due, on the one hand, to conditions of application which are becoming increasingly demanding, and on the other hand to the growing use of ceramic materials. For although the latter make excellent face materials, they are far more sensitive to cavitation erosion than metallic face materials.

Details

Industrial Lubrication and Tribology, vol. 45 no. 2
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 1 March 1987

Antonio Strozzi

A class of exact solutions to the elastohydrodynamic problem to be used as test cases is presented. A numerical solution to the elastohydrodynamic problem according to the…

73

Abstract

A class of exact solutions to the elastohydrodynamic problem to be used as test cases is presented. A numerical solution to the elastohydrodynamic problem according to the Petrov—Galerkin method is developed. The appearance of spurious numerical undulations in the film profile is examined. A comparison between analytical and numerical results is employed to determine which numerical schemes limit the outcome of numerical oscillations without compromising the solution accuracy.

Details

Engineering Computations, vol. 4 no. 3
Type: Research Article
ISSN: 0264-4401

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