Pump 1 delivers fluid through flow-control valve 2 and the body of pressure reducing valve 3 to the right end of power cylinder 4, moving piston 9 to the left. Fluid from the left end of the cylinder is discharged to the tank. A part of the fluid delivered by the pump passes through pipeline 5 into valve 3, and through notch a of valve spool 6 to the tank. Chambers d and b are connected by passage f, drilled axially through spool 6. Owing to the throttling of the fluid passing through notch a, the pressures in chambers d and b differ. By turning screw 7 it is possible to obtain almost complete equality of the forces acting on spool 6 from the two chambers. A constant pressure drop is maintained over flow-control valve 2 because, upon a change in pressure in the system, spool 6 is shifted either by the action of the changed pressure or that of spring 8, thereby changing the amount of fluid discharged to the tank. Relief valve 10 protects the system against overloads.
$4187$CHP,Dr$