DEVELOPMENT OF A DIRECT PRESSURE-SENSING WATER HYDRAULIC
RELIEF VALVE

Kenji Suzuki and Eizo Urata 
 

Department of Mechanical Engineering, Kanagawa University – Rokkakubashi 3-27-1, Kanagawa-ku, Yokohama 221-8686, Japan 

suzuki@kanagawa-u.ac.jp,  urata@kanagawa-u.ac.jp

Abstract

        A balanced-piston-type water hydraulic relief valve working at a rated pressure of 14 MPa is developed. The design focuses on preventing cavitation and improving the static characteristics and stability. To prevent cavitation, the main valve has two throttles of nearly equal dimensions in series. As static characteristics, pressure override and hysteresis are considered. To reduce the pressure override, the supply pressure is directly led to the pilot valve. To reduce the hysteresis, the main valve is supported by hydrostatic bearings, which eliminate Coulomb friction in the main valve. To improve the stability of the main valve, a viscous damper is attached to the main valve besides inserting a damping orifice between the main- and the pilot valves. Simulation of static- and dynamic characteristics are carried out to determine the valve dimensions. The experimental results for a flow rate of up to 20 litres/min showed that the measured pressure override and hysteresis are about 1% and 0.1% of the pre-set pressure, respectively. The developed relief valve did notradiate cavitation noise in the range (maximum pressure 14 MPa) of the experiments.

Keywords: Water hydraulics, Relief valve, Cavitation, Pressure override, Hysteresis, Hydrostatic bearing


 

BACK


©2008 Fluid Power Net All rights reserved. Disclaimer