Fluid pressure regulator establishing a stable output fluid pressure

A multi-stage pressure regulator for controlling a pressurized fluid supplied to a load at a substantially constant pressure with changes in the output flow of the fluid, comprising a regulating valve section including a poppet valve unit between an input chamber adapted to be connected to a fluid supply and an output chamber, a pressure relief valve unit coupled to said poppet valve unit and having a bleed opening, a bleed section including a first pressure responsive support connected to said pressure relief valve and subjected to said output chamber pressure for urging said pressure relief valve to a valve open state, a second pressure responsive support connected to said pressure relief valve for urging said pressure relief valve to a closed position, a pilot pressure control section having a pilot pressure chamber coupled to said second pressure responsive support, a precision bleed unit coupled to the input chamber of said poppet valve unit and to said pilot pressure chamber, a variable orifice unit connected to said pressure control unit and operable to pass said bleed fluid from said pilot pressure chamber, a passageway connected to said orifice unit to pass said bleed fluid to said output chamber of said poppet valve unit, said first and second pressure responsive supports having a ratio control on said pressure relief valve such that the pressure in the pilot pressure chamber must exceed the pressure in said output chamber in a selected ratio to establish an equilibrium position of the pressure relief valve for releasing a single small bleed of fluid to stabilize the position of the poppet valve unit and the main bleed flow from the output side of the poppet valve unit.

A poppet unit for a regulating valve having an input chamber and an output chamber extending therefrom with a valve seat wall at the connection of said chambers and with a compensating chamber aligned with said valve seat wall, comprising an hour-glass shaped poppet body having a first enlarged end portion for engaging said seat wall to close and open the connection of said chambers and a second enlarged end for sealing insertion into the compensating chamber and an intermediate connecting portion between said enlarged end portions, said connecting portion having a substantially smaller cross-section than said enlarged end portions, said enlarged end portions, having outer end walls and having opposed facing lateral extension surfaces joined to said connecting portion within said input chamber and constructed to establish a first substantially balanced fluid force on said poppet body, said poppet body having a central opening, a valve stem located within said central opening sealing said central opening and extending outwardly of said central opening and including first and second locking elements abutting the end walls of said first and second enlarged, end portions, said stem and valve body including a pressure transfer opening between the stem and the central opening for connecting the compensating chamber to the output chamber, said locking elements being constructed to establish output pressure to the opposite ends of said body member to establish a second substantially balanced fluid force on said poppet body.