| 摘要 |
PROBLEM TO BE SOLVED: To provide an impeller capable of reducing noises originating from turbulent vortices generated in the neighbourhood of the main plate of the impeller and to provide a centrifugal blower emitting low noises. SOLUTION: The centrifugal blower 40 of multiple vane type is composed chiefly of the impeller 63, a casing 11 enclosing the impeller 63, and a motor 14 to rotate impeller 43. The impeller 43 is structured so that a plurality of vanes 33 are fixed to the peripheral edge of the disc-shaped main plate 61 in such a way that their farther ends are tied by a ring-shaped side plate 62. In the main plate 61 portion near the inner edges of the vanes 33, an undulation 64 with surface unevenness is formed along the peripheries of the inner edges. The undulation 64 crushes small the turbulent vortices grown by collision of a gas flow Z1 with the main plate 61 and convergence of flows immediately before the grown vortices reach the vanes 33, which should lessen the noise emission. |
