Pilot operated fluid control valve

Claim 1

A pilot operated liquid control valve comprising a valve body including a base section and a closure section, said base section having means defining an inlet and an outlet with a valve seat therebetween, a first flexible diaphragm having an outer portion clamped between said base and closure sections of said valve body and a movable inner portion cooperating with said seat to control the flow of liquid from said inlet to said outlet, means defining a bleed hole for directing a limited flow of liquid from an inlet chamber on one side of said first diaphragm to a second chamber on the other side of said first diaphragm, said base and closure sections defining a vent passage for directing liquid from said second chamber around at least said inner portion of said first diaphragm to said outlet and providing for the release of liquid flowing through said bleed hole, a liquid impervious second flexible disphragm having an outer portion secured to said closure section and an inner portion flexible between an open position permitting the flow of liquid through said vent passage from said second chamber and a closed position blocking the flow of liquid through said vent passage, means for sealing said outer portion of said second diaphragm to said closure section to prevent the liquid within said vent passage from contacting the outer surface of said second diaphragm, an electrically operated solenoid having a disc-like armature disposed adjacent said outer surface of said second diaphragm, spring means associated with said armature for urging said inner portion of said second diaphragm towards said closed position, and means for energizing said solenoid to effect movement of said armature and said inner portion of said second diaphragm to said open position.