摘要 |
A pressure relief valve including a valve member movable between open and closed positions to control fluid flow. A body member is provided which receives a piston operatively connected to the valve member for operating same. The piston defines a first chamber in the valve body extending above the piston and a second chamber 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.
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