Patent ID: 8083477

Claim:
A centrifugal fan comprising: a plurality of blades; a casing comprising a base plate perpendicular to a rotation axis of the blades and a sidewall extending upwardly from the base plate, the base plate and the sidewall cooperatively defining a space for receiving the blades therein, the sidewall defining an opening in a side thereof functioning as an air outlet of the centrifugal fan, an air channel being defined between outmost ends of the blades and the sidewall; and a tongue being detachably mounted to one end of the sidewall adjacent to the air outlet, the tongue comprising a guiding surface protruding towards the outmost ends of the blades; wherein a first locking unit is formed on the one end of the sidewall adjacent to the air outlet, the tongue comprises an elongated body and a second locking unit formed on the body, the body has a connecting surface matching with an inner surface of the sidewall adjacent to the air outlet, and the second locking unit is detachably interlocked with the first locking unit to mount the tongue to the sidewall.