Compressor modulation delay valve for variable capacity compressor

摘要

A modulation delay valve for a variable capacity compressor operative to prevent the premature reduction of the pumping capacity of the compressor. A compressor suction chamber pressure sensing bellows, located in a pressure control cell, regulates a hydraulic control valve which in turn controls the flow of oil to a hydraulic cylinder operative to vary the displacement of the compressor. The delay valve functions, by sensing a compressor discharge reference pressure, to delay the operation of the hydraulic control valve by cutting-off communication of the suction pressure signal to the bellows cell allowing the compressor to maintain its maximum pumping rate. Upon the compressor discharge chamber pressure falling below the reference pressure the delay valve discharge cavity pressure correspondingly falls, allowing the delay valve to open communication between the bellows control cell and the compressor suction chamber to resume modulation of the compressor.