The back shroud which turns the impeller of the poly aerofoil air blowers and poly aerofoil air blower

摘要

PROBLEM TO BE SOLVED: To provide an impeller capable of reducing the noise 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 multi-vane blower 40 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. Each inter-vane part 65 of the main plate 61 positioned between vanes 33 is cut out in the front about the rotating direction. This cut-out shape of the inter-vane part 65 relieves 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.