Patent ID: 7794198
Filing Date: 2010-09-14
Classification: F04D

Abstract:
1. A centrifugal fan comprising: a plurality of blades circularly arranged, wherein the plurality of blades are interposed between a ring-like lateral plate and a main plate, and integrated; a casing including therein the plurality of blades, wherein the casing has a discharge outlet, and an inlet with an internal diameter equal to that of the plurality of blades circularly arranged; and a motor with a rotation axis thereof connected to the main plate, wherein the motor is fixed to the casing, wherein each of the plurality of blades has a plurality of asperities on one of the dorsal or ventral sides thereof, wherein a side of the lateral plate of the plurality of blades is arranged at the inlet, wherein the asperities are formed with a projection and a recess alternately repeated from a front edge toward a rear edge thereof in a cross section vertical to a rotation axis of the plurality of blades, wherein the asperities extend in a direction parallel to the rotation axis of the plurality of blades, and wherein the asperities extend an axial distance less than the axial length of the plurality of blades.