Time cycle controller for pneumatic valve

Abstract

The invention relates to an economical, reliable time cycle controller for controlling the frequency and duration of the open and close cycles of a valve which may be hydraulically activated, but which is preferably operated by pneumatic means. An electrically actuated pilot valve is employed to control the application of pressurized fluid to the pneumatic main valve. The pilot valve in turn is sequentially controlled by two electrically activated delayed release relays having the characteristic that once energized by a pulse of current, they will hold their contacts in the energized position for a period of time determined by the setting of an adjustable pneumatic timer provided on each relay. A unique circuit connection arrangement between the power source, the variable time delayed release relays, and the two energizing coils of the pilot valve effects the automatic operation of the pilot valve at a frequency determined by the time delayed release setting of one relay and for a duration determined by the timed delayed release setting of the other relay. Additionally, protective devices are provided to insure that the pilot valve will never open the main valve when the battery voltage is insufficient to insure the reclosing of the main valve, and a capacitor is charged whenever the main valve is open to provide an energy pulse sufficient to effect the shifting of the pilot valve to its closing position in event of a power failure or manual disconnection of the power source from the control circuit.