| 摘要 |
A control valve body is provided for series connection in a fluid flow control line in which alternating fluid flow in opposite directions at different speeds is desired. The body has a main flow passage formed therethrough and also includes a by-pass passage by-passing a central portion of the main flow passage. Throttle valve structure is operatively associated with the by-pass passage to variably throttle the flow of fluid therethrough and a control valve is shiftably supported in the main flow passage central portion for movement between open and closed positions. Spring structure is provided for yieldingly biasing the control valve toward the open position thereof and the control valve includes a fluid impact portion disposed in the central portion of the main flow passage for fluid impact pressure thereon to shift the control valve toward its closed position against the spring structure which yieldingly biases the control valve toward its open position responsive to fluid flow through the main passage in the direction in which the fluid flow is to be reduced. Dashpot structure is operatively connected between the body and the control valve for varying the closing rate of the control valve.
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