Valves for the control of pressure fluid

Claim 1

A pressure fluid control valve, comprising: (a) a valve body member having ports therein; (b) a mobile valve control member movable relative to the valve body member between a port-closing position and port-opening position to control communication between the ports in the valve body member, (1) one of said members defining a recess having an upstream wall and a downstream wall, and (2) the other member having a sealing surface facing the recess; (c) a seal including a sealing element floatingly housed in the recess, said sealing element, sealing surface and recess being dimensioned and positioned such that said sealing element is deformed into sealing engagement with one of the recess walls and with the sealing surface, in the port-closing position of the mobile valve control member, solely by fluid pressure acting on the sealing element; and (d) a recess vent comprising at least one longitudinal groove formed on the surface of said member defining a recess and having a vent opening at one end thereof which opens into the downstream wall of said recess, said groove having a depth less than that of said recess and being disposed directly adjacent to said sealing surface, said groove being dimensioned and positioned such that it is covered, and thereby closed, by the sealing element, when the latter is performing its sealing functions, and is uncovered when said sealing ring is subjected to excessive distortion during its movement relative to the valve body member to a port-opening position, under conditions of a high pressure differential acting on the sealing ring, so as to relieve the fluid pressure acting on the sealing element and causing the excessive deformation thereof.