Pressure valve

摘要

The pressure valve is actuated by pressurized fluid and has a housing with a high-pressure space and a low-pressure space separated from each other by a partition. The partition has a bore accommodating a valve member. Axial passages are made in the body of the valve member for establishing alternating communication between the spaces upon the displacement of the valve member. The low-pressure space receives a pressure-relief valve spring-urged away from the partition and movable by the action of pressure selectively supplied to initiate relieving of the high-pressure space. The pressure-relief piston has an axial bore. The pressure valve incorporates an auxiliary piston in the axial bore of the pressure-relief piston and it cooperates with the valve member to displace the latter. The body of the valve member is provided with throttling passages communicating with the axial passages. The flow passage area of the throttling passages is substantially smaller than that of the axial passages, and the throttling passages are arranged so that during the high-pressure space pressure-relieving operation, the two spaces communicate via the throttling passages until the effort applied to the valve member by the auxiliary piston overcomes the effort applied to this valve member from the high-pressure chamber.