Patent ID: 8147186

Claim:
A centrifugal compressor comprising: a revolving shaft; an impeller mounted to the revolving shaft; a casing configured to house the impeller; a diffuser section connected downstream of the impeller; and a volute section connected downstream of the diffuser section, and being configured to compress fluid by applying a centrifugal force to the fluid by rotating the impeller; a parting member configured to divide a flow channel in the diffuser section and the volute section into a plurality of channels in a direction of circulation of the fluid so as to define a hub-side flow channel and a shroud-side flow channel; and a flow rate adjuster configured to lower the flow rate of the fluid flowing in the shroud-side flow channel and enabling the fluid to flow in the hub-side flow channel at a high flow rate when the flow rate of the fluid compressed by the impeller is low and not lowering the flow rate of the fluid flowing the shroud-side flow channel to enable the fluid to flow both in the shroud-side flow channel and the hub-side flow channel when the flow rate of the fluid compressed by the impeller is high, wherein the diffuser section includes a hub-side diffuser section in the hub-side flow channel and a shroud-side diffuser section in the shroud-side flow channel, at least the hub-side diffuser section is provided with vanes, and a cross-sectional area of the flow channel in the shroud-side diffuser section is larger than the cross-sectional area of the flow channel in the hub-side diffuser section.