| 摘要 |
The present invention provides a two-stage centrifugal compressor. The compressor of this invention has a simplified refrigerant passage structure and effectively cools its electric motor in addition to bearing parts using an existing refrigeration cycle without having another external cooling unit. This compressor thus reduces a consumption of electric power, and improves the operational performance and operational efficiency of a refrigeration system. In the two-stage centrifugal compressor of this invention, a plurality of internal fluid passages (14) are regularly formed on the internal surface of the upper and lower end portions of an external housing (13) so as to allow first and second compression parts to communicate with each other through the interior space of the external housing (13). Upper and lower bearing housings (21a and 21b) are fixedly mounted to the upper and lower ends of the external housing (13), with a plurality of fluid openings (213) being regularly formed on the bearing housings (21a and 21b) and communicating with both compression chambers (31 and 32) of the first and second compression parts, corresponding to the internal fluid passages (14) of the external housing (13d). The second compression part has the second compression chamber (32) within a compressing casing (34), receiving an inlet part of a diffuser (27) and surrounding outer part thereof and provided with a refrigerant discharging port (361), and has an internal cover (36) with a fluid passage (362) communicating with the fluid openings (213) of the upper and lower bearing housings (21a and 21b). |
