Abstract: A compressor for compressing a gas comprises an impeller wheel (1) mounted within a housing (2) defining an inlet and an outlet (6). The inlet comprises an outer tubular wall (7) extending away from the impeller wheel in an upstream direction and forming a gas intake portion (8) of the inlet, and an inner tubular wall (9) of diameter D extending away from the impeller wheel in an upstream direction within the outer tubular wall (7) and defining an inducer portion (10) of the inlet. An annular gas flow passage (11) is defined between the inner and outer tubular walls (9, 7) and has an upstream end and a downstream end separated by a length L1 measured along its axis. The upstream end of the annular passage (11) communicates with the intake or inducer portions of the inlet through at least one upstream aperture and at least one downstream aperture (13) communicates between a downstream portion of the annular flow passage (11) and the impeller.

Abstract: A compressor for compressing a gas comprises an impeller wheel (1) mounted within a housing (2) defining an inlet and an outlet (6). The inlet comprises an outer tubular wall (7) extending away from the impeller wheel in an upstream direction and forming a gas intake portion (8) of the inlet, and an inner tubular wall (9) of diameter D extending away from the impeller wheel in an upstream direction within the outer tubular wall (7) and defining an inducer portion (10) of the inlet. An annular gas flow passage (11) is defined between the inner and outer tubular walls (9, 7) and has an upstream end and a downstream end separated by a length L1 measured along its axis. The upstream end of the annular passage (11) communicates with the intake or inducer portions of the inlet through at least one upstream aperture and at least one downstream aperture (13) communicates between a downstream portion of the annular flow passage (11) and the impeller.