| 摘要 |
PROBLEM TO BE SOLVED: To effectively eliminate large and small vortexes which are generated at the blade edges by the drifting of air flow passing through an impeller, and to suppress the deterioration of aerodynamic force performance and increase of noise caused by an eddy flow. SOLUTION: Two platy mouse rings 8 and 9 comparting a suction side and a discharge side at the outer periphery of the impeller, and an outer wall 10 surrounding the outer periphery of the mouse rings are provided, and a turning flow circulating space 11 having an opening 12 opposed to the blade of the impeller 7 is provided between the above mouse rings 8 and 9. Since the cross section area of the turning flow circulating space 11 is different over the whole circumference, when the air flow passing through the impeller is drifted, the large and small vortexes which are generated at the blade edges are effectively eliminated by large and small turning flow circulating spaces 11 acting as air circulation passages, and thus, the deterioration of aerodynamic force performance and the increase of noise caused by the eddy flow can be suppressed.
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