Pilot operated sequencing valve

Abstract

A valve, for sequentially operating a plurality of main valves, including a valve body having a plurality of inlet ports for connection to a plurality of main valves, respectively, and a chamber for receiving high pressure fluid from the inlet ports. A pilot valve, which may be operated by a solenoid energized and deenergized periodically by an electric timer, relieves pressure in the chamber each time it opens and permits pressure to build up in the chamber each time it closes. A sequencing valve member permits only one inlet port to be in communication with the chamber each time the pilot valve is opened, so as to relieve pressure in only the main valve connected to that one inlet port. The sequencing valve member may be an apertured rotatable disk slidably engaging valve seats surrounding the inlet ports. An operator responds to successive closings of the pilot valve for indexing the sequencing valve member so that each inlet port in turn communicates with the chamber. The operator may include a piston-cylinder device, the cylinder communicating with the chamber, and a pawl and ratchet mechanism between the piston rod and the sequencing valve member. The aperture in the sequencing valve disk may be large enough so that at all times at least one of the inlet ports communicates with the chamber. An auxiliary port may be provided connected to a source of high pressure fluid, and an auxiliary valve pressurizes the chamber when it opens and cuts off pressure to the chamber from the auxiliary port when it closes, the auxiliary valve being open only when the pilot port is closed. In this way, the sequencing valve member operates even if one or more of the inlet ports is plugged.