| 摘要 |
A hydraulic system 10 includes at least one actuator 12, a source 14 of pressurised fluid for delivering pressurised fluid at a system pressure to a control valve 16 which is user operated to control the flow of fluid from the source 14 to the actuator 12 at a load pressure, along a load pressure path 38, a flow control apparatus 20 for controlling the flow of fluid from the source 14 to the control valve 16, the flow control apparatus including an actuating part 50 which is biased by a resilient device 24 to a condition in which the flow control apparatus 20 provides for a maximum flow of fluid to the control valve 16, actuating part 50 movement by the resilient device 24 being resisted by system pressure fluid and being supported by fluid at a control pressure, the control pressure being derived from the load pressure, and wherein the system includes a pressure control device 30 to which the load pressure is communicated, the pressure control device 30 being user operated either to deliver the control pressure to the flow control device 20 at load pressure or a modified pressure which is less than the load pressure.
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