Toshihisa Imai

Blower having a sound-damping structure

A blower comprises an impeller which can function to raise the pressure of a fluid and delivers it; a driving device for driving the impeller; and a fan casing which includes a fluid path to inspire the fluid from the outside and deliver it to the outside through the impeller; wherein the fan casing is at least partly formed by a hard porous structural unit whose specific gravity is continuously changed in at least one of the direction of thickness and a direction of surface.