Apparatus for regulating the pressure and rate of flow of fluid supplied

Abstract

Apparatus which regulates the pressure and the rate of flow of fluid supplied by a variable-delivery radial piston or vane pump whose output can be changed by moving a ring-shaped slide block transversely of the rotor. The slide block is engaged by a relatively small piston which is subjected to fluid pressure corresponding to that at the outlet of the pump, and by a relatively large piston which is disposed opposite the smaller piston and is subjected to fluid pressure which is controlled by a regulating valve receiving pressurized fluid from the outlet. The outlet is connected with a set of first consumers, such as hydraulic cylinder and piston units, and the pressure of fluid which is delivered to first consumers can be regulated by a set of series- or parallel-connected pilot valves one of which is permanently connected with the regulating valve and the others of which are connectable to the regulating valve only by discrete two-way valves which can be opened by remote control. The outlet of the pump is further connected to a second consumer, such as a rotary hydraulic motor, by way of several flow restrictors each of which is followed by a digitally controlled shutoff valve. The number of open shutoff valves determines the amount of fluid which flows to the inlet of the hydraulic motor.