| 摘要 |
PROBLEM TO BE SOLVED: To provide a multiblade centrifugal fan achieving both securement of blast performance and a reduction in NZ noise. SOLUTION: In this multiblade centrifugal fan 1, an impeller 10 having a number of blades 11 is rotatably provided in a scroll-shaped casing 2. A plurality of projections 12, 13 parallel to the direction of the rotating shaft of the impeller 10 are provided in a range of 0°<θ<45° and/or 90°<θ<180° on a side surface 5 in the casing 2 where θ presents the angle of the impeller 10 in a rotating direction based on a straight line connecting the center S1 of the rotating shaft of the impeller 10 to the rounded center S2 of the tongue portion 6 of the casing 2. COPYRIGHT: (C)2010,JPO&INPIT
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