• Title/Summary/Keyword: Balancing Piston

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Flow Characteristics of Pressure Balancing Valve with Various Piston Shapes (피스톤 형상변화에 따른 압력평형밸브의 유동특성연구)

  • Kim, Tae-An;An, Byeong-Jae;Kim, Yun-Je
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.2168-2173
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    • 2003
  • Pressure balancing valve is one of important control devices, which is fully automatic and no manual controls, regulating or adjustments are needed. It is typically used to maintain constant temperature of working fluid in power and chemical plants and domestic water supply systems. Pressure balancing valve is composed of body, cylinder and balancing piston. Therefore, the balancing piston shapes are important design parameters for a pressure balancing valve. In this study, numerical and experimental analyses are carried out with two different balancing piston shapes. Especially, the distribution of static pressure is investigated to calculate the flow coefficient($C_v$). The governing equations are derived from making using of three-dimensional Navier-Stokes equations with standard ${\kappa}-{\varepsilon}$ turbulence model and SIMPLE algorithm. Using commercial code, PHOEIC, the pressure and flow fields in pressure balancing valve are depicted.

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Modification of Balancing Piston for Trimming of Impeller Diameter for Maintaining Axial-Thrust Balance in Low-Specific-Speed Multistage Centrifugal Pumps (저비속도 원심 회전차 외경가공에 따른 축추력 불균형을 감쇄시키기 위한 평형 피스톤 수정방안에 관한 고찰)

  • Yoo, Il-Su;Park, Moo-Ryong;Yoon, Eui-Soo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.9
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    • pp.875-882
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    • 2011
  • In the present study, the imbalance in the axial-thrust and variation in the volumetric efficiency that occurred during the trimming of impeller diameter were investigated. The present study was focused on low-specific-speed multistage centrifugal pumps with a balancing piston as the balancing mechanism. The effects of impeller trimming on the axial-thrust balance in multistage pumps with horizontal and vertical axes were compared. The results showed that impeller trimming resulted in an additional axial-thrust acting in direction of pump inlet. The axial-thrust imbalance due to impeller trimming was more severe in the vertical-axis pumps than in the horizontal-axis pumps. The rate of increase in the diameter of the balancing piston, which was proportional to the rate of impeller trimming, was evaluated to maintain the axial-thrust balance. Furthermore, a simultaneous increase in the piston length and piston diameter was more effective for reducing the axial-thrust imbalance along with the volumetric efficiency drop.

Study on the Improved Measurement of Piston Assembly Friction Force in an IDI Diesel Engine (간접 분사식 디젤기관 피스톤 결합체 마찰력 측정 장치의 개선 및 마찰력 측정)

  • Cho, S.W.;Kim, S.S.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.3 no.2
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    • pp.77-85
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    • 1995
  • Among mechanical friction losses in an engine, the piston assembly and cylinder components accounts for the majority of the losses. The movable bore technique has been developed and turned out to be the most reliable technique in measuring the instantaneous friction of piston assembly. The weakness of this system, however, was the presence of the protruded top of movable bore necessary for pressure balancing. Because of the protruded part the piston could not be taken out without disassembling the crankshaft. Present study was carried out with a system of removable top of the movable bore so that it was possible to make frequent piston removals. The effects from engine speed, oil viscosity, engine load and elastic contact pressure of piston rings on the frictional characteristics have been evaluated with the improved equipment. Also, frictions of each member of piston assembly were measured.

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A Study on the Hydrostatic Test of Slipper Pad for Hydraulic Piston Motor (유압 피스톤모터용 Slipper Pad의 정압시험에 관한 연구)

  • 함영복;김광영;김형의
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.04a
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    • pp.645-649
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    • 1997
  • In case of swash plate type axial piston hydraulic motor, hydrostatic bearing used to achieve the lubrication effect on the mechanical sliding contact areas between the following parirs ; sliooer-pad and swash plate,piston and cylinder bore,valve plate and cylinder block, etc. This study discussed the basic charateristic for the hydrostatic slipper-pad bearings with the capillary or orifice restrictor under static load condition. And, we also development of hydrostatic bearing tester for hydrostatic balancing test of pistion & slipper-pad assembly, and some experimental data on supply pressure step responce are reported.

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A Study on the Balancing of V/W-type Reciprocating Air Compressor (V/W형 왕복동 공기압측기의 평형에 관한 연구)

  • 김형진;김성춘;김정만;김의간
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.1
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    • pp.24-31
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    • 2004
  • Recently, as the marine compressor power is increased, vibration problems on the marine vessel with V/W type reciprocating compressor have been occurred. A research on the balancing of marine V/W type reciprocating compressor has hardly been reported though a number of researches on the balancing of rotating machinery have been conducted. As a V/W type compressor has high capacity with long stroke, compact size and high center of gravity, It is easy to have a vibration problem by a little bit unbalanced force and moment. In this study, calculation methods for balance weight of the V/W type reciprocating compressors, which have different piston weight and asymmetry structure, are formulated. And their reliability were verified by comparing calculated balance weight with the experimental results of the real marine V/W type reciprocating compressors.