Patent attributes
The present invention discloses volute for a centrifugal fan, which comprises a volute tongue having an inner wall; wherein, the volute tongue has an enclosed noise-reducing chamber, the volute tongue has a plurality of holes for allowing the air flow to enter into the noise-reducing chamber; and a sound collector and a speaker are disposed in the noise-reducing chamber. In the present invention, during the use of the centrifugal fan, a gas flow can enter the cavity through the holes on the inner wall. The sound collector can acquire a noise signal and transmit it to a controller, and the controller calculates a noise-reduced audio signal according to the acquired signal and then controls the speaker to play the corresponding reduced noise according to the noise-reduced audio signal, so that the active noise reduction is realized. With such a structure, the vortex at the volute tongue is eliminated, thus the fan noise is reduced and the fan efficiency is improved.
