Multistage throttling characteristics of reverse direction impact of pilot operated check valve

The aim of this study was to improve the reverse impact characteristics of large-flow pilot operated check valves, meanwhile reduce oscillation, cavitation and unloading time. Three different main poppets were selected, and the impact pressure and flow were set as 30 MPa and 1000 L/min, respectively. The cavitation phenomenon was explored based on the analysis of gas-liquid two-phase flow by Fluent software, and then experimental verification was performed. Meanwhile, the dynamic characteristics of pilot operated check valves were analyzed by the impact test system. The simulation results showed that the fluid pressure clearly decreased while flowing through the poppet area. The sudden decrease of flow area at the orifice port of the poppet resulted in an increase in flow-velocity, because the cavitation area appears on the side of the main poppet. A stepped throttling structure could effectively reduce the cavitation area, preventing the generation of cavitation. The experimental results showed that the pressure oscillation of a stepped main poppet significantly reduced during the process of unloading, at 28.41 MPa; with a flow gradient of 4.86×105 L/min2; unloading time significantly reduced, for 711 ms; indicating it opened more rapidly and dynamic characteristics was superior. It can be concluded that the stepped throttling structure could effectively reduce the pressure oscillation of a pilot operated check valve during the process of unloading, improve response speed, enhance the impact properties, and reduce cavitation. This verified the correctness of the simulation and the rationality of the cavitation index.

[1]  Matti Vilenius,et al.  Water Hydraulics--A Versatile Technology (特集「水圧システムの開発に向けて」) , 1998 .

[2]  Y. S. Liu,et al.  Experimental investigation of flow and cavitation characteristics of a two-step throttle in water hydraulic valves , 2002 .

[3]  Ato Kitagawa,et al.  Water hydraulic high-speed solenoid valve Part 1: Development and static behaviour , 2004 .

[4]  Wang Hu.  Fluid-solid coupling analysis of large flow hydraulic controlled check valve on hydraulic support , 2014 .

[5]  Eizo Urata,et al.  Development of a Water Hydraulic Pressure-Compensated Flow Control Valve , 2008 .

[6]  Hong Ji.  EFFECTS OF INTERNAL STRUCTURE ON CAVITATING NOISE OF HYDRAULIC RELIEF VALVE , 2002 .

[7]  Kenji Suzuki,et al.  Development of Cam-Drive Type Proportional Valve for Water Hydraulics , 2012, Int. J. Autom. Technol..

[8]  Kenji Suzuki,et al.  Development of a Direct Pressure-Sensing Water Hydraulic Relief Valve , 2008 .

[9]  Franc Majdic,et al.  Experimental validation of the lifetime performance of a proportional 4/3 hydraulic valve operating in water , 2011 .

[10]  Jun Zou,et al.  Interactions between poppet vibration and cavitation in relief valve , 2015 .

[11]  Ye Jian.  Numerical Investigation of Cavitation Erosion /Solid Particle Erosion in High Differential Pressure Control Valves in Coal Liquefaction , 2013 .

[12]  Igor Velkavrh,et al.  Improving the performance of a proportional 4/3 water–hydraulic valve by using a diamond-like-carbon coating , 2013 .

[13]  G. Schffels.  Developments in water hydraulics , 1996 .

[14]  Li Gui-hua.  Numerical simulation of flow field in hydraulic cone valve for water medium , 2007 .

[15]  Zhao Jiyun,et al.  Design and Research for the Water Low-pressure Large-flow Pilot-operated Solenoid Valve , 2014 .