Multicylinder rotary compressor and compressing system and refrigerating unit provided with same

摘要

The present invention relates to a multicylinder rotary compressor and a compressing system and a refrigerating unit each provided with the multicylinder rotary compressor. Two-stage (cylinder) rotary compressor provides a motor-operating element and a rotary compressing element in a closed vessel, and the rotary compressing element includes a first rotary compressing element and a second rotary compressing element. This two-stage rotary compressor provides a refrigerant gas switching means comprised of a communicating pipe one end of which is opened in the dosed vessel and the other end of which is opened in a back pressure portion for a vane having no spring In the second rotary compressing element, a branch pipe provided in the midway portion of this communicating pipe and a three-way valve attached to a branch point in the branch pipe. Further, a through hole in the second rotary compressing element is dosed with a sealing member. During high rotation speed a high pressure refrigerant gas, which flows from the closed vessel to the communicating pipe is supplied to the back pressure portion for the vane so that the second rotary compressing element is made in an operation mode, and during low rotation speed the high pressure refrigerant gas is relieved through the branch pipe so as not to supply the back pressure portion for the vane with the refrigerant gas, whereby the second rotary compressing element is made in a non-operation mode. The present invention form a compressing system and a refrigerating unit each using the two-stage rotary compressor.