A hydraulic control device for the distribution of pressure flue sig to a preferred consumers and consumer to subordinate

摘要

Priority valve system with pressure-flow compensation and signal control having first, a restricted orifice which can be satisfied when flow requirements therethrough are sufficiently large in combination with, second, a closed center primary control valve equipped with an hydraulic detent unlatch mechanism and hydraulically disposed downstream of the orifice to receive the flow directed thereto by the orifice, all to provide appropriate signals controlling the priority valve.P P Through this intervening, novel two component control combination, the priority valve is controlled to supply flow to a priority load and, in addition, has an auxiliary outlet chamber connected to an auxiliary motor with the purpose to cut off the auxiliary chamber flow whenever the priority flow is sufficient to satisfy only the restricted orifice. The primary valve is a center dump valve which, when its unlatch mechanism is automatically tripped by priority-load stall-out, dumps pressure causing the priority valve to reconnect to the auxiliary motor, and also causing a commensurate reduction in output of a pressure- compensated main pump provided for the system.