Patent ID: 8851444

Claim:
A pilot operated valve assembly comprising: a valve housing including an inlet port having an inlet passageway and an outlet port having an outlet passageway separated by an aperture forming a valve port, the valve housing having a cylindrical bore; a valve piston reciprocally moveable within the bore and coupled to a valve member operable to open and close the valve port; an adapter plate attached to an open bore end of the housing; a pilot passageway extending through the housing and the adapter plate and fluidly connecting the inlet passageway to the open bore end of the housing; a solenoid operable to open and close the pilot passageway; and a restrictor mechanism operable to selectively restrict flow through the pilot passageway based on the difference in fluid pressure on either side of the restrictor mechanism, wherein the restrictor mechanism comprises a restrictor piston having a piston orifice therethrough, and a biasing member biasing the restrictor piston toward a first position allowing full flow from the pilot passageway to the open bore end of the housing, the restrictor piston moveable to a second position wherein the piston blocks all flow from the pilot passageway to the open bore end of the housing except for flow through the piston orifice.