Patent ID: 7914267
Filing Date: 2011-03-29
Classification: F04C

Abstract:
1. A multistage compressor for a CO2 cycle that includes a low-stage side rotary compressing mechanism and a high-stage side scroll compressing mechanism driven by an electric motor in a closed housing, and carries out two-stage compression by discharging CO2 refrigerant gas compressed in the low-stage side rotary compressing mechanism into the closed housing and taking intermediate pressure refrigerant gas in the closed housing by the high-stage side scroll compressing mechanism, wherein a gas injection circuit for injecting intermediate pressure CO2 refrigerant gas extracted from a refrigerant circuit into the closed housing is connected to the closed housing, and wherein the pressure ratios of the low-stage side rotary compressing mechanism and the high-stage side scroll compressing mechanism are substantially equivalent, and the ratios of displacement volume are also substantially equivalent.