| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a multi-blade centrifugal fan that allows a channel extension part of a scroll casing to correspond to the strength and extent of vortex, suppresses the rising of low-frequency sounds and the deterioration in blowing efficiency due to turbulence of air flow and, thereby, permits low noise and high efficiency, and to provide an air conditioner using the multi-blade centrifugal fan. <P>SOLUTION: The multi-blade centrifugal fan 1 in which an impeller 15 is freely rotatably disposed around a rotation shaft 14 in the scroll casing 2 starting the winding from a tongue includes the channel extension part 20, 21 extended in the rotation shaft 14 direction and formed on the outer part than the impeller 15 of upper and lower end surfaces of the scroll casing 2, wherein the channel extension part 20 of the upper end surface 8 side on which a suction port 10 of the channel extension part 20, 21 is disposed is configured to have a height Hsi of ≤5% of the total direction height Ht of rotary shaft of channel 3 of the scroll position at least in the range of winding angle θ of ≤30° when the winding angle in the rotational direction starting from the tongue is set θ. <P>COPYRIGHT: (C)2012,JPO&INPIT |
