Electrically operated proportional flow control hydraulic valve and

Abstract

A proportional fluid flow control hydraulic valve including a valve body in which a by-pass flow passage leads from an inlet port to a by-pass outlet port. A valve chamber is arranged between the inlet port and a regulated flow outlet port and the by-pass outlet port. The by-pass flow passage includes an annular auxiliary flow channel which extends in bypassing relationship around the valve chamber. A valve member movably mounted in the valve chamber has valve ports therein for controlling fluid flow from the inlet port and the auxiliary fluid flow channel past the valve member to the regulated flow passage. In one form, the valve member is normally disposed in balanced hydraulic equilibrium in the valve chamber to prevent fluid flow from the inlet port through the auxiliary fluid flow channel and the valve ports in the valve member into the valve chamber and thence into the regulated flow passage. In another form the valve member is normally disposed in a state of balanced hydraulic equilibrium to establish fluid flow from the auxiliary fluid flow channel through the valve ports in the valve member into the valve chamber and thence into the regulated fluid flow passage. Means are provided, including a manually operable remotely controlled solenoid device, for unbalancing the hydraulic equilibrium of the valve member in the valve chamber to cause movement of the valve member and the valve ports therein into or out of communication with the auxiliary flow channel. A pressure compensating valve is movable in a valve chamber in communication with the by-pass outlet passage and the regulated flow passage, to compensate for pressure and flow fluctuations.