Solenoid-operated pilot-actuated valve

Abstract

A solenoid-operated pilot-actuated valve is provided of the diaphragm type which has particular utility for irrigation purposes. The valve also finds industrial utility where it is desirable to control large amounts of flow energy with a small control signal. The valve includes a diaphragm chamber into which fluid is introduced to establish a fluid pressure which normally forces the diaphragm against an annular seat in the valve to maintain the valve in a closed condition. A stationary bleed tube is provided which extends through the diaphragm into the diaphragm chamber. A solenoid plunger normally closes off the upper end of the bleed tube. However, when the solenoid is energized, the plunger is withdrawn and opens the bleed tube, the diaphragm chamber is drained sufficiently to reduce the pressure therein to a point at which the diaphragm is forced off its seat by the upstream fluid pressure, and the valve is opened. Fluid is introduced into the diaphragm chamber from the upstream fluid pressure when the valve is closed through a restricted annular passage between the bleed tube and a guide mounted on the diaphragm. Movement of the diaphragm causes the guide to move up and down with respect to the bleed tube to provide a self-cleaning action in the annular passage.