Refrigerating system using scroll type compressor

Abstract

A refrigerating system including a refrigeration circuit and a scroll type compressor provided with two volume control mechanisms to allow the system to selectively perform full load operation and unloaded operation. The scroll type compressor includes two scroll members of known construction meshing with each other to define compression chambers and a suction chamber and is combined with the refrigeration circuit having an outdoor heat exchanger, an expansion valve, an indoor heat exchanger and a four-way change-over valve to provide a heat pump type refrigerating system. The volume control mechanisms each include a pair of bypass apertures in the fixed scroll member communicating with a valve chamber having a valve member slidably mounted therein and normally biased to an open position by a spring. The bypass apertures, of which one communicates with the suction chamber and the other communicates with one of the compression chambers, and the valve chamber constitute a bypass passageway. A pressure introducing pipe opens in the valve chamber. Upward movement of the valve member brings the two bypass apertures in communication with each other through the valve chamber to enable the system to perform a volume control operation. In another application, four volume control mechanisms are located symmetrically and divided into two blocks through a flow passage switching device to assign two mechanisms to one block. By this arrangement, the system is able to perform volume control operation in three stages, or able to operate selectively at maximum load, intermediate load and minimum load.