US 4,699,351 AGranted

Pressure responsive, pilot actuated, modulating valve

AssigneeTarget Rock Corporation

InventorRobert A. Wells

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Abstract

The pressure responsive, pilot actuated, modulating valve comprises a main valve assembly which defines with the housing a first chamber and controls flow of fluid from an inlet port to an outlet port. A pressure responsive piston is provided which defines with the housing a second chamber. A vent passageway is provided in the piston for communicating the second chamber with the outlet port. A pilot valve assembly is provided to control flow through the vent passageway. A means is provided for selectively actuating the pilot valve assembly. A discharge orifice is comprised in the main valve assembly for communicating the vent passageway with the outlet port. A vent valve assembly is disposed to control flow of fluid between the first chamber and the discharge orifice. A restricted conduit means is disposed to coact with the main valve assembly to provide a variable flow area communicating the inlet port with the discharge orifice and the first chamber when the vent valve assembly and the main valve assembly are in an open position and which flow area varies in direct proportion to the amount the main valve assembly is open to thereby vary fluid pressure in the first chamber and provide forces on the main valve assembly which act counter to the direction of movement of the main valve assembly.

A pilot operated modulating valve comprising:

(a) a housing having an inlet port communicating with a source of fluid under pressure and an outlet port communicating with a place at a fluid pressure lower than the fluid pressure at the inlet port;
(b) a main valve assembly having a movable main disc and a main valve seat in said housing for controlling flow of fluid from said inlet port to said outlet port;
(c) the movable main disc having a first chamber therein;
(d) said main disc having a discharge orifice for communicating said first chamber with the outlet port;
(e) a piston mounted in said main valve assembly and housing for reciprocative movement relative to the movable main disc and the housing, the piston and housing defining therebetween a second chamber;
(f) a vent valve assembly having a first movable valve member within the main disc and carried by said piston and a first valve seat in the main disc for controlling flow of fluid to and from said first chamber;
(g) a vent passageway in said piston for communicating said discharge orifice with said second chamber;
(h) a pilot valve assembly including a second movable valve member carried by the housing and a second valve seat at the vent passageway carried by the piston for controlling flow of fluid from said second chamber through the vent passageway and discharge orifice;
(i) actuating means connected to said second movable valve member to lift the second valve from the seat by controllable amounts;
and
(j) restrictive conduit means in the said main valve assembly sealed by the main disc from the inlet port when the main disc is seated and exposed to the inlet port when the main disc is lifted from its seat, said restrictive conduit providing a variable flow area communicating the inlet port with said first chamber in direct proportion to the opening of the movable main disc from the associated main valve seat to thereby vary fluid pressure in said first chamber to provide forces acting on the movable main disc counter to the direction of movement of the movable main disc.

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Abstract

Claims15