Fluid flow control valves

Claim 1

A control valve for controlling the flow of liquid through aperture means in a piston and including an axial rod for moving said piston through said liquid, an annular outer valve seat on one side of said piston outwardly of the aperture means therein, a valve guide comprising a cylindrical member surrounding said rod and having an integral flange at one end engAging said one side of said piston, an annular member separate from said valve guide and seated on the opposite end thereof, said annular member having a peripheral edge part extending radially outwardly of said valve guide to define an inner valve seat, a flexible annular valve element having its outer periphery on one face normally sealingly engaging said outer valve seat and an inner periphery laterally located on said valve guide with its opposite face normally sealingly engaging said inner valve seat, said inner and outer peripheries being lifted off their respective seats by pressure difference acting across said flexible element according to the direction in which the pressure difference acts, the integral flange of said valve guide limiting movement of the inner periphery of said valve element away from said inner valve seat, axial duct means extending through said guide means including its integral flange for the flow of liquid past the inner periphery of said valve member when the latter is lifted from its seat, an annular stop member carried by said rod and having an outer periphery which overlies the outer periphery of said valve element and limits displacement of its outer periphery away from said outer valve seat, and means clamping said piston, valve guide, inner valve seat and annular stop member on said rod.