Druckentlastungsventil mit Hilfsdruckvorrichtung

摘要

A pressure relief valve including a valve member (28) movable between open and closed positions to control fluid flow. A body member (56) is provided which receives a piston (60) operatively connected to the valve member for operating same. The piston defines a first chamber (58a) in the valve body extending above the piston and a second chamber (58b) extending below the piston. System fluid is introduced into the chambers and the differential fluid pressure in the chambers applies a loading force to the piston, and therefore to the valve member in its closed position. When the system pressure, and therefore the pressure in the chambers, exceeds a predetermined amount the pressure in one of the chambers is vented, causing the piston to move to an open position and permit opening movement of the valve member.