Centrifugal fan is widely used in all kinds of large and medium-sized factories and civil buildings, large venues and other places. as a general ventilation for gas exchange, centrifugal fans transport air or other non-flammable and explosive, house corrosive gases, there are no viscous substances in the gas, the dust and hard matter particles contained not more than 150 mg/m³, temperature not more than 80℃. The efficiency and ratio of centrifugal fan to a sound level are up to or superior to the a grade standard formulated by the Ministry of Machinery Industry. It is used to transport corrosive gas and is made of FRP or steel anticorrosive paint and stainless steel. A large part of the power increase of centrifugal fans depends on the impeller of the fan. The so-called impeller is that we usually see the fan blade, many people think that the fan power forward because its speed is faster. The operation power of the fan is directly related to the speed of the fan. But the impeller is a more energy-efficient way to ensure that it increases power while using the same power. Impeller can improve the working power of centrifugal fan has two advantages, one is the diameter of impeller, the other is the inclination of impeller. Assuming that the impeller is larger in diameter, the type of centrifugal fan is large enough. Then the power will be effectively improved, which is why the larger power fan in the volume of the larger reason. There is also the centrifugal fan impeller tilt degree, assuming that the tilt degree is smaller, then the power will be relatively small. On the contrary, assuming a large inclination, the power of the centrifugal fan will increase. But this is also within a certain scale, because there is no way to tilt the impeller to 90 degrees, at most within an acute angle.