Pump flow restricting device

摘要

A restrictor mechanism is provided in a pilot operated solenoid valve that restricts the pilot flow to the actuating piston of the valve if the pressure differences within the valve are great. This reduces the actuating forces allowing the valve to open or close softly. As the pressures within the valve start to balance, the restrictor device opens, allowing full pilot flow to hold the valve in position.

主权项

1. 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.