GB746913A - Improvements in or relating to a hydraulic pressure surge dampening device - Google Patents

Abstract

746,913. Fluid-actuated valves. DENISON ENGINEERING CO. Feb. 15, 1954, No. 4388/54. Class 135. A surge dampening device comprises a body having inlet and outlet ports 26, 27, a valve 43A, loaded e.g. by a spring 42A acting on a transverse valve pin 42 passing through slots 41 in a cylinder 35, to close a passage from inlet to outlet via a series of ports 40, passage 31 and slots in a cylinder cap 37, and means to control the rate of opening of the valve by inlet pressure including a fluid-receiving chamber 39 with a restricted outlet 45A, opening movement of the valve tending to increase the fluid pressure in the chamber, e.g. via spring 47A and piston 47, and a valve element 46 independently movable in the chamber and in response to the increased chamber pressure to reduce the size of the restricted outlet. Increased pressure in chamber 39 due to an inlet pressure surge acts on the piston 47 to close the valve 46 on the orifice 45A so that the chamber pressure passes only slowly via orifices 52, 45A and passages 53A, 31 to the outlet and valve 43A only opens a few ports 40. When the surge is over, outlet pressure exists in chamber 39 and the piston 47 and valve 43A are moved back to open all the ports 40. In a modification the passage 53A has an opening to the inlet closed by a check valve for relieving outlet pressure.