CONTROL VALVES

摘要

A control valve working section and an inlet section are provided in a multiple section control valve bank, said control valve working section having a pressure fluid inlet port, a pressure inlet chamber spaced from said port, check valve means between said inlet port and inlet chamber, an inlet chamber connected to said inlet port, first and second work ports adapted to be connected to a fluid actuated device, first and second work chambers connected to said ports and spaced on opposite sides of said inlet chamber, first and second exhaust chambers on opposite sides of said work chambers from the inlet chamber, a pair of metering and logic chambers with one chamber on each side of the inlet chamber between the inlet chamber and the work chambers, a main bore extending through and interconnecting all of said chambers, a valve element movable in said bore from a neutral position to first and second work positions for selectively connecting said chambers and establishing fluid communication therebetween whereby in a work position fluid flows from the inlet port through said metering and logic chambers to one of said work ports, said inlet section having an inlet port adapted to be connected to a source of fluid pressure, an outlet port and chamber connected to said inlet port and to a valve section inlet port, an exhaust port, a spaced by-pass chamber connected to said exhaust port, and a signal chamber between said exhaust port and by-pass chamber, a bore extending through and connecting said chambers in said inlet section, a valve member movable in said bore between said signal chamber and said by-pass chamber effective to control fluid communicating from the inlet to the outlet port and being movable to a by-pass position by-passing fluid from the inlet through the by-pass chamber to said exhaust port, biasing means opposing the movement of said valve member to said by-pass position, a connection between said outlet port of said inlet section and said inlet port of said control valve section delivering fluid therebetween, logic means connecting the signal chamber of said inlet section and a metering and logic chamber of said control valve whereby the pressure in said signal chamber is varied in accordance with the difference between the pressure in the inlet port of the inlet section and the fluid pressure at said metering and logic chamber to vary the biasing means opposing movement of said inlet section valve member whereby the flow of fluid from the inlet port to the outlet port of the inlet section is varied by by-passing fluid.