How to Reduce the Noise of Industrial Fans and Blowers by Xianrun Blower? Part 2

(6) Installing silencers in industrial centrifugal fan air inlet and air outlet is also a good way to reduce noise, absorbing the sound energy by porous sound absorption material.
When sound waves go through the air inlet and outlet of porous sound absorption material, most sound energy is consumed away and becoming heat by overcoming frictional resistance and viscous drag resistance, so as to reduce the aerodynamic noise produced by centrifugal blower. 
Practice shows that, installing the silencers in air inlet or air outlet of centrifugal fan can usually reduce aerodynamic noise about 20 ~ 30 db (A).

Xianrun Blower centrifugal fan with silencer

(7) The size of the industrial centrifugal fan impeller outlet is generally larger than impeller inlet of front disc, so the air flow in the fan will causing many eddy flow at inlet arc section. Eddy flow will generate aerodynamic noise by frequently collision with casing and air inlet parts. In this case, designing the rectifying ring and baffle outside of air outlet, can effectively prevent the eddy flow in the centrifugal fan air inlet, thus reducing the aerodynamic noise generated by centrifugal fan.

(8) Applying backward swept blades in industrial centrifugal fan, that is to say, the impeller blades lean forward in impeller air outlet, while the impeller blades lean backward in impeller air inlet, avoiding gas flow channel changing rapidly. 
All these can reduce the aerodynamic noise by preventing eddy flow.

Xianrun Centrifugal Blower Impeller

(9) Using wall plates or components as grading shield or protection cover, the noise will be blocked during the spreading. This will control the noise within a certain scale, and reduce centrifugal fan noise. 

Xianrun Blower centrifugal fan production cover