Patent ID: 9322408
Filing Date: 2016-04-26
CPC Classification: F04D

Claim Text:
1. A centrifugal fan comprising: a shell comprising: a top plate; a bottom plate; and a sidewall connecting to the top plate and the bottom plate, wherein the top plate, the bottom plate, and the sidewall define an air outlet; an impeller disposed in the shell; a tongue portion disposed in the shell and neighboring the air outlet; and a protrusion disposed on an inner wall of the shell and physically connected to the top plate and the bottom plate; wherein there is a minimum distance P between the tongue portion and the impeller; the shell has a width W, the impeller has a diameter D, and a gap A is defined between the impeller and the protrusion, in which 0.5×P≦A≦0.7×(W−D).