Federbelastetes Rückschlagventil

摘要

An apparatus for regulating the flow of an operating fluid to and from a user device. Housing means has a cylinder chamber and a passage for flow of the operating fluid. Valve means is movable in the passage between a normally closed position and an open position in which it permits flow of the operating fluid in pressurized condition to the user device. Control fluid inlet means communicates with the cylinder chamber for admitting a control fluid under pressure into the latter. A valve control piston is operatively associated with the valve means and movable in the cylinder chamber from a rest position via an intermediate position to a control position in which later it displaces the valve means to open position to permit operating fluid to flow away from the user device. First and second channel means are provided in the piston and each communicates with the chamber. The first channel means has a larger and the second channel means has a substantially smaller cross-sectional area and only the first channel means communicates with the inlet means during movement of the piston from its rest position to its intermediate position, while only the second channel means communicates with the inlet means during movement of the piston from its intermediate position to the control position.