Proportional valve assembly with adjustable throttle

摘要

The valve assembly controls hydraulic equipment, such as a hydraulic ram (10). It consists of a throttle (2) which controls the flow from the pump (49). A bypass (50) in the pump delivery line (7) is fitted with a pressure limiting valve (14), controlled partly by the pressure at the throttle outlet, sensed by a pipe (15), and partly by a spring (16). An additional control is effected by the pressure from a second pressure limiting valve (19) which acts on a piston (17) which in turn acts on the spring. The pressure from the second pressure limiting valve can be adjusted by varying the force of the spring.