Centrifugal Blower and Air Conditioner with Centrifugal Blower

Abstract

A centrifugal blower having a hub ( 2 ), to an axis section of which a rotating shaft ( 4 a ) of a motor ( 4 ) is connected, and a blade wheel ( 1 ) provided with blades ( 3 ) that are stood on the outer periphery of the hub ( 2 ) at predetermined spacings in a circumferential direction and whose front edge ( 3 a ) is inclined forward in a rotation direction, wherein a bellmouth ( 5 ) having an air suction opening ( 6 ) is provided on the air suction side of the blade wheel ( 1 ). A circulation flow f 2 is formed, in which the flow flows from the blowout side of the blade wheel ( 1 ) through the rear side of the air suction opening ( 6 ) in the bellmouth ( 5 ) to the blade wheel ( 1 ) into which the flow is sucked again.

1 . A centrifugal blower including an impeller ( 1 ) having a hub ( 2 ) with a central portion connected to a rotation shaft ( 4   a ) of a motor ( 4 ), a plurality of vanes ( 3 ) arranged on a peripheral portion of the hub ( 2 ) at predetermined intervals in a circumferential direction, the vanes provided with front rims ( 3   a ) inclined toward the front in a rotational direction, and a bellmouth ( 5 ) provided with an air intake port ( 6 ) arranged at an air intake side of the impeller, the centrifugal blower being characterized in that: 
 a circulating flow (f 2 ) is generated to flow out from an outlet side of the impeller ( 1 ), flow back into the impeller ( 1 ), and pass through a rear side of the air intake port ( 6 ) of the bellmouth ( 5 ).    
   
   
       2 . A centrifugal blower including an impeller ( 1 ) having a hub ( 2 ) with a central portion connected to a rotation shaft ( 4   a ) of a motor ( 4 ), a plurality of vanes ( 3 ) arranged on a peripheral portion of the hub ( 2 ) at predetermined intervals in a circumferential direction, the vanes provided with front rims ( 3   a ) neither inclined toward the front nor the rear in a rotational direction, and a bellmouth ( 5 ) provided with an air intake port ( 6 ) arranged at an air intake side of the impeller, the centrifugal blower being characterized in that: 
 a circulating flow (f 2 ) is generated to flow out from an outlet side of the impeller ( 1 ), flow back into the impeller ( 1 ), and pass through the rear side of the air intake port ( 6 ) of the bellmouth ( 5 ).    
   
   
       3 . The centrifugal blower according to  claim 2 , characterized in that the vanes ( 3 ) in the impeller ( 1 ) are entirely inclined in the rotational direction.  
   
   
       4 . The centrifugal blower according to  claim 2 , characterized in that the vanes ( 3 ) in the impeller ( 1 ) are entirely inclined opposite the rotational direction.  
   
   
       5 . The centrifugal blower according to  claim 1  or  2 , characterized in that the vanes ( 3 ) in the impeller ( 1 ) include vane tips inclined in the rotational direction.  
   
   
       6 . The centrifugal blower according to  claim 1  or  2 , characterized in that the vanes ( 3 ) in the impeller ( 1 ) include vane tips inclined opposite the rotational direction.  
   
   
       7 . The centrifugal blower according to  claim 1 , characterized in that when an inner diameter of the air intake port ( 6 ) of the bellmouth ( 5 ) is represented by D 0 , an inner diameter of the vanes ( 3 ) in the impellers ( 1 ) is represented by D 1 , and an outer diameter of the vanes ( 3 ) is represented by D 2 , 0<(D 0 -D 1 )/(D 2 -D 1 )<0.6 is satisfied.  
   
   
       8 . The centrifugal blower according to  claim 1 , characterized in that when an inner diameter of the air intake port ( 6 ) of the bellmouth ( 5 ) is represented by D 0 , the inner diameter of the vanes ( 3 ) in the impeller ( 1 ) is represented by D 1 , and the outer diameter of the vanes ( 3 ) is represented by D 2 , −0.3<(D 0 -D 1 )/(D 2 -D 1 )<0.3 is satisfied.  
   
   
       9 . The centrifugal blower according to  claim 1 , characterized in that a ring body ( 9 ), ( 20 ) having a predetermined width in a centrifugal direction is attached to axial distal ends of the vanes ( 3 ) in the impeller ( 1 ).  
   
   
       10 . The centrifugal blower according to  claim 9 , characterized in that when a width in the centrifugal direction of the ring body ( 20 ) is represented by H, and the outer diameter of the vanes ( 3 ) of the impeller ( 1 ) is represented by D 2 , 0.05<ki=H/D 2 <0.225 is satisfied.  
   
   
       11 . The centrifugal blower according to  claim 1 , characterized in that a diagonal diffuser ( 23 ) is arranged at the outlet side of the impeller ( 1 ) to guide air that is blown out of the impeller ( 1 ) diagonally rearward.  
   
   
       12 . The centrifugal blower according to  claim 1 , characterized in that a diagonal centrifugal diffuser ( 23 ) is arranged at the outlet side of the impeller ( 1 ) to guide air blown out of the impeller ( 1 ) in a centrifugal direction from a diagonal rear side.  
   
   
       13 . The centrifugal blower according to  claim 1 , characterized in that a circulation space (S) is formed at a peripheral side of the air intake port ( 6 ) of the bellmouth ( 5 ) to allow passage of the circulating flow (f 2 ).  
   
   
       14 . The centrifugal blower according to  claim 1 , characterized in that when an exit side height of the vanes ( 3 ) in the impeller ( 1 ) is represented by B and an outer diameter of the vanes ( 3 ) is represented by D 2 , B/D 2 ≧0.113 is satisfied.  
   
   
       15 . The centrifugal blower according to  claim 1 , characterized in that the hub ( 2 ) of the impeller ( 1 ) has an outer diameter D 3  that is smaller than the outer diameter D 2  of the vanes ( 3 ).  
   
   
       16 . The centrifugal blower according to  claim 15 , characterized in that when an exit side height of the vanes ( 3 ) of the impeller ( 1 ) is represented by B and an outer diameter of the vanes ( 3 ) is represented by D 2 , B/D 2 ≧0.08 is satisfied.  
   
   
       17 . The centrifugal blower according to  claim 1 , characterized in that the number of the vanes ( 3 ) in the impeller ( 1 ) is 5 to 15.  
   
   
       18 . The centrifugal blower according to  claim 1 , characterized in that the number of the vanes ( 3 ) in the impeller ( 1 ) is 20 to 50.  
   
   
       19 . The centrifugal blower according to  claim 2  characterized in the number of the vanes ( 3 ) in the impeller ( 1 ) is 30 to 72.  
   
   
       20 . An air conditioner including a heat exchanger ( 15 ) and a blower (X) arrange in an air duct ( 14 ) formed in a casing ( 13 ), the air conditioner being characterized in that the centrifugal blower according to  claim 1  is employed as the blower (X).