Pilot-operated pressure regulator valve

摘要

A pilot-operated pressured regulator valve includes a main valve for controlling refrigerant flow in a refrigeration suction line. A pilot valve which is responsive to evaporator pressure controls a flow of high pressure refrigerant to the main valve for modulating the main valve. A bleed is provided for bleeding the high pressure refrigerant from the main valve. A solenoid-actuated shut-off valve controls the bleed flow from the main valve. The shut-off valve is selectively closed for maintaining the high pressure refrigerant in the main valve for closing the main valve. A bleed flow of high pressure is provided to the main valve when the shut-off valve is closed in order to maintain the main valve closed.