| 摘要 |
A cushion valve arrangement for reducing the rate of pressure build up and relieving pressure rebounds in a fluid conduit. The valve housing defines first and second fluid ports, a fluid passage communicating therebetween, and a cushion passage communicating between the fluid passage and the first and second fluid ports. A valve spool is disposed in the fluid passage and defines an axial bore, within which is disposed a slideable valve member. When the pressure and flow suddenly builds up, the valve member is biased to an open position permitting high pressure fluid to pass through the axial bore and radially out through a passage in the spool into the cushion passage from which the fluid flows to the other conduit. There is a dashpot on either end of the valve spool and the incoming high pressure fluid biases the valve spool away from its neutral position gradually reducing the flow area defined by the radial passage in the spool and the cushion passage, and thus gradually reducing the amount of fluid dumped to the other conduit. As the spool moves away from its neutral position, the opposite dashpot is reduced in volume, the excess fluid from that dashpot passing through a restricted orifice and out to the adjacent, lower pressure conduit. The size of the restricted orifice determines the rate at which the spool moves toward a position shutting off the flow into the cushion passage. This arrangement also provides a combination of crossover or double relief valving as well as anti-cavitation valving.
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