| 摘要 |
An arrangement for pumping fluids includes at least one variable-output pump and a drive therefor. An auxiliary pump is also driven by the drive and discharges control fluid at a discharge rate which corresponds to the speed of rotation of the drive. A throttle valve is located in a discharge conduit of the auxiliary pump, and the pressure of the control fluid upstream of the throttle valve controls the displacement of a slide valve between two positions thereof in one of which the control slide controls the variable-output pump toward increasing the output thereof, while in the other of such positions the pump is controlled toward a reduced output thereof. In addition to the pressurized fluid, which acts on the control slide with a first force, a spring is provided which acts on the control slide with a second force opposing the first force. One of these forces is varied in response to variations in the output rate of the variable-output pump so that the ratio of the first force to the second force increases with the diminishing output rate of the variable-output pump. Advantageously, the position of an adjusting element of the variable-output pump is used as an indication of the output rate of the pump. The signal derived from the position of the adjusting element is used either for tensioning or relaxing the spring, or for increasing or decreasing the flow-through cross-sectional area of the throttle valve.
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