| 摘要 |
PROBLEM TO BE SOLVED: To provide a centrifugal compressor capable of preventing damage of a base material in contact of an impeller blade with a casing shroud even in the compressor using a relatively thin impeller blade with a simple structure. SOLUTION: Among a surface opposed to the impeller blade in the casing shroud, an upstream part running along a rotary shaft of an impeller wheel is coated with resin, and a downstream part having an angle relative to the rotary shaft is coated with metal so that only a resin coating is cut by runout of the rotary shaft, and the shock is small, and there is no fear of having influence on the impeller blade. Weight is reduced more than when thermally spraying metal over the whole surface. The downstream part becoming a relatively high temperature, having the angle relative to the rotary shaft and having little influence by the runout of the rotary shaft is coated with metal by thermal spraying to enhance film thickness accuracy of the part. Clearance between the impeller blade and the casing shroud can be reduced so that compression efficiency is not reduced.
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