Back pressure valve fitted in control valve - has spring loaded valve element with pressure release holes through disc portion

摘要

A hydraulic power circuit has a control valve whose sealing is not impared when set normally in the closed position. The valve has a control element that moves from a neutral position either to the pressure source connection or to the reservoir connection. A spring keeps the valve in the closed position. The closing element (14) is a flat disc with a rounded edge (18) that fits in a cylindrical seating (11). The disc carries a raised circular sealing surface (17) that runs at right angles to the valve borehole (10). Several vertical orifices (19) pass through the disc from the sealing surface (17) to the underside. These are equally spaced round the closing plug.