| 摘要 |
A control valve assembly incorporates a flow control valve, and a piston which are both biassed in the same direction against pressure in an hydraulic accumulator by first and second respective springs. Accumulator pressure in a control chamber also acts to urge the flow control valve in the same direction as it is biassed by the spring and pressure from a pump acts to bias the flow control valve in the opposite direction. A pilot dump valve controlling communication between the chamber and an outlet connection is normally biassed into a closed position by a third spring. The dump valve is adapted to open at a cut-out pressure to dump pressure from the chamber, and the cut-out pressure is determined by the area of the seating of the dump valve over which the pressure in the chamber acts, and the force in the third spring. A cut-in pressure at which the dump valve closes is determined by the area of the first piston and the force in the second spring.
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