Centrifugal compressor with recirculation structure

A centrifugal compressor adapted to be used in a chiller system, the centrifugal compressor comprising:

• a casing having an inlet portion and an outlet portion;
• the inlet portion including an impeller;
• the impeller having a shaft assembly;
• a motor arranged to rotate the shaft assembly in order to rotate the impeller;
• an outlet portion including a diffuser and a volute assembly;
• a recirculation structure including a recirculation path, the recirculation path supplying a refrigerant from the diffuser to a recirculation discharge cavity, the recirculation path including a recirculation pipe that introduces the refrigerant toward the inlet portion;
• a plurality of recirculation discharge guide vanes disposed to surround the recirculation discharge cavity;
• an annular groove disposed between the recirculation pipe and the plurality of recirculation discharge guide vanes;
• and
• an annular plate disposed between the annular groove and the recirculation discharge cavity.

A centrifugal compressor comprising:

• a casing having an inlet portion and an outlet portion;
• an inlet guide vane disposed in the inlet portion;
• a recirculation structure including a recirculation pipe and a recirculation discharge cavity;
• an impeller attached to a shaft;
• a motor arranged to rotate the shaft in order to rotate the impeller;
• a plurality of recirculation discharge guide vanes;
• an annular groove disposed between the recirculation pipe and the plurality of recirculation discharge guide vanes;
• and
• an annular plate disposed between the annular groove and the recirculation discharge cavity,
• the recirculation structure being configured and arranged to impart a swirl to a flow of refrigerant into the inlet portion, and
• the recirculation pipe being configured to flow the refrigerant toward the plurality of recirculation discharge guide vanes.