GB612344A - Improvements relating to spring-controlled check valves for fluid pressure - Google Patents

Abstract

612,344. Check valves. WESTINGHOUSE BRAKE & SIGNAL CO., Ltd., CADMAN, N. G., and VIGOR, B. C. May 14, 1946, No. 14546. [Class 135] In a spring-loaded check valve, the flow of fluid under pressure past the valve member in its open position is restricted by a choke in such a way that the equilization of fluid pressures on the two sides of the valve member is delayed and chattering is thereby minimized. In an embodiment, pressure fluid entering at 2, Fig. 1, acts on a piston 4 and pushes it up against the opposition of its loading spring 6. This opens the valve constituted by the rib 7 and seat gasket 11 and allows the fluid to flow through a choke 10 in the piston and out through the outlet 3. Owing to the restriction, a lowered pressure is produced on the upper side of the piston and the valve is maintained open by the higher inlet pressure acting on the lower side of the piston. In a modification, the movable member comprises valve heads 15, 16 rigidly interconnected by a guide stem 22. Initially, the entering fluid flows around head 16, along the stem 22, and acts on head 15 to raise it and so allow the fluid to flow to the outlet. The raising of head 15 causes head 16 to close on to its seat so that the fluid is forced to flow through a choke 23. This produces a lowered pressure which, acting on the small upper surface of head 16, cannot cause the valve to close while the inlet pressure is maintained on the under surface of head 16. Piston 4 and head 16 may be replaced by flexible diaphragms. Reference has been directed by the Comptroller to Specification 610,931, [Group XXXIV].