Centrifugal blower

Abstract

A centrifugal blower is designed such that D/R, which is a ratio of a radius D of an air inlet to a radius R of an impeller, ranges from 85% to 87%, and such that r/R, which is a ratio of a radius r of a cross-section of a bell mouth of the centrifugal blower to the radius R of the impeller, ranges from 8% to 10%. With such a structure, a geometric size of the bell mouth is optimized, thus enhancing the blowing efficiency of the centrifugal blower. As a result, superior performance of the centrifugal blower can be ensured.

What is claimed is: 
     
         1 . A centrifugal blower, comprising:
 a scroll casing having an inlet port, formed in an upper surface of the scroll casing, and an outlet port formed in a side surface of the scroll casing;   an impeller installed in the scroll casing, the impeller having a cylindrical shape, with a hub being disposed in the impeller such that the impeller is rotated by rotating the hub; and   a bell mouth having a ring shape and disposed on an edge of the inlet port of the scroll casing, the bell mouth forming an air inlet of the scroll casing and having a semi-circular cross-section,   wherein D/R, which is a ratio of a radius (D) of the air inlet to a radius (R) of the impeller, ranges from 85% to 87%.   
     
     
         2 . The centrifugal blower as set forth in  claim 1 , wherein r/R, which is a ratio of a radius (r) of the cross-section of the bell mouth to the radius (R) of the impeller, ranges from 8% to 10%. 
     
     
         3 . The centrifugal blower as set forth in  claim 1 , wherein
 D/R, which is the ratio of the radius (D) of the air inlet to the radius (R) of the impeller, is 86%, and   r/R, which is a ratio of a radius (r) of the cross-section of the bell mouth to the radius (R) of the impeller, is 9%.   
     
     
         4 . The centrifugal blower as set forth in  claim 2 , wherein
 D/R, which is the ratio of the radius (D) of the air inlet to the radius (R) of the impeller, is 86%, and   r/R, which is the ratio of the radius (r) of the cross-section of the bell mouth to the radius (R) of the impeller, is 9%.   
     
     
         5 . The centrifugal blower as set forth in  claim 1 , wherein, when blowing air, circulating airflows or vortexes form below the bell mouth, and magnitudes of the vortexes are reduced as a distance between the bell mouth and each of the vortexes increase with respect to an inflow direction.