Pilot-operated solenoid valve apparatus

Abstract

A pilot-controlled solenoid valve apparatus includes a valve housing having an entrance chamber, an exit chamber, and a discharge chamber formed therein. An inlet valve controls fluid pressure flow from the entrance chamber to the exit chamber while an outlet valve controls fluid pressure flow from an exit chamber to the discharge chamber which exhausts to atmosphere. The inlet and outlet valves each include respective membrane diaphragms which have control chambers disposed on one side; which control chambers are pressurized by means of respective inlet and outlet control valves. Disposed on each of the membrane diaphragms are annular symmetric bodies which each have a longitudinal bore formed therein to allow communication between the respective control chambers and the exit and discharge chambers when the respective control valves are opened. An inlet and an outlet solenoid valve arrangement controls operation of the respective inlet and outlet control valves. A valve anchor associated with each of the solenoid valves has formed on one side thereof, a pilot valve seat. Formed on the opposite side of the valve anchor is a control valve body, which by being formed integrally with the pilot valve body, allows simultaneous operation of the solenoid and control valve portions of the solenoid valve apparatus. A bias spring engages the valve anchor near the control valve body to urge the anchor and thus, the control valve body toward the annular symmetric body on which is formed the control valve seat, when the solenoid valve arrangement is not energized.