Pressure regulating and on-off valve

摘要

A two stage relief valve, in which the pilot flow is limited by an active flow control element to a specific maximum predetermined level, to extend its maximum operating pressure range and to improve its operating characteristics. The downstream orifice may be fully open and of a fixed area type, or may be controlled by a spring or solenoid biased member. With the downstream orifice solenoid or stepper motor operated, the relief pressure level becomes responsive to an electrical input signal.