Centrifugal fan

Abstract

According to the present invention, there are provided diffusers 115 which extend from portions close to the outer diameter of the centrifugal impeller 111 to the downstream side of a current of air, on the outer diameter side of the centrifugal impeller 111 and around the circumference. Due to the foregoing, while a current of air blown out from the impeller 111 is being straightened by the diffusers 115 , the dynamic pressure of the current of air is converted into static pressure. Consequently, it is possible to make the current of air flow stably into the outlet 114 side without disturbing it. Therefore, while the generation of noise is being suppressed, the total pressure of the fan 110 can be sufficiently increased.

1 . A centrifugal fan comprising: a centrifugal impeller having a number of blades around a rotary shaft, the centrifugal impeller sucking air in the axial direction of the rotary shaft and blowing it out in the radial direction; a casing for accommodating the centrifugal impeller, the casing having a plurality of outlets for blowing out air; and stator blades arranged in the casing, extending from the outer diameter side of the centrifugal impeller to the downstream side of an air current.  
     
     
         2 . A centrifugal fan according to  claim 1 , wherein the stator blades are arranged around the circumference on the outer diameter side of the centrifugal impeller.  
     
     
         3 . A centrifugal fan according to  claim 1 , wherein the centrifugal impeller has blades arranged backward, the impeller outlet angle of which is larger than 90°.  
     
     
         4 . A centrifugal fan according to  claim 1 , wherein the entrance angle of the stator blade is not more than 20°.  
     
     
         5 . A centrifugal fan according to  claim 1 , wherein the cross-section of the stator blade is an airfoil shape.