Automatic constant pressure valve device

摘要

PCT No. PCT/JP94/01432 Sec. 371 Date Jan. 23, 1996 Sec. 102(e) Date Jan. 23, 1996 PCT Filed Aug. 31, 1994 PCT Pub. No. WO95/06834 PCT Pub. Date Mar. 9, 1995The present invention relates to an automatic constant-pressure lift valve provided with a pilot valve unit having an A valve unit and a B valve unit, and an external control force applying means that can be simply adjusted to set a predetermined valve-outlet pressure. A main valve unit is constructed so that an abnormal rise in the valve-outlet pressure can be avoided at start and stop and continuous operation of a pumping or conveying pump facility. The automatic constant-pressure lift valve has a construction capable of easily maintaining watertightness when the line is shut off. The pilot valve unit is not provided with any fixed flow restriction regulating passage, such as a needle valve. When the main valve unit, and the A valve unit and the B valve unit of the pilot valve unit are clogged, those valves open automatically for automatic cleaning. This constant-pressure lift valve has an excellent industrial effect.