Patent ID: 7686586

Claim:
A compressor for compressing a gas, the compressor comprising: an impeller mounted for rotation about an axis within a chamber defined by a housing; the housing having an axial intake and an annular outlet volute; the chamber having an axial inlet and an annular outlet; said axial inlet being defined by a tubular inducer portion of the housing and said annular outlet being defined by an annular diffuser passage surrounding the impeller, the diffuser having an annular outlet communicating with the outlet volute; the impeller comprising a plurality of blades each having a front edge rotating within the housing inducer portion, a tip sweeping across the annular inlet of the diffuser, and a curved edge defined between the front edge and the tip which sweeps across a surface of the housing defined between the inducer and the diffuser; the impeller having an inducer diameter defined by the outer diameter of the front edges of the blades, and an outer diameter defined by the outer diameter of the blade tips; each blade being backswept relative to the direction of rotation of the impeller about said axis; wherein the angle of backsweep at any point on a blade surface is in the range 45° to 55°; wherein the ratio of the impeller inducer diameter to the impeller outer diameter is in the range of 0.59 to 0.63; and wherein the ratio of the diffuser outlet diameter to the impeller outer diameter is between 1.4 and 1.55.