PURPOSE: To lower an air blowing noise by providing an extendedly provided part, which extends from a side plate side to a main plate side, neighboring the inner periphery of an impeller, in a prescribed range directing from the vicinity of a reed part of a housing toward the volute expanding direction.
CONSTITUTION: A first extendedly provided part 11 is extended/formed in a region corresponding to a prescribed range, being directed from the vicinity of a reed part 21 of a housing 1 toward the volute expanding direction. This first extendedly provided part 11 is extended/provided from a side part (5) side toward a main plate (4) side, neighboring the inner periphery of an impeller 2. With this, in the reed part 21, the vicinity of a leading edge inclining to the side plate 5 of a blade 3 turns to a dead water region, because of the extendedly provided part 11. Accordingly, an occurrence of a circulation flow in the vicinity of a leading edge 1a can be restricted. In addition, an air blowing noise caused by both the turbulence accompanying the occurrence of the circulation flow and entrained air can be reduced, thereby realizing calm operation.
KAMATA MASASHI
KIDERA YASUHITO
