Centrifugal fan is mainly composed of: impeller, housings, couplings, shafts. Impeller is to produce pressure and energy the main working parts chassis mainly used to introduce gases and exhaust gases, while the gas part of the kinetic energy into pressure energy; coupling is used to connect the motor and blower, torque shaft, install and secure the impeller through the coupling and motor.
Forward impeller produce the most stress, flow and speed is constant, the impeller diameter minimum required, but generally lower; after the impeller on the contrary, the pressure of minimum required maximum impeller diameter, which is generally higher; radial impeller is somewhere in between. Leaf lines with straight blades the most simple Airfoil of the most complex.
Blade surface in order to have the right kind of velocity distribution, generally uses the curved blades, such as thickness of circular-arc blade. Usually has a cover plate of the impeller, to increase the strength and reduced impeller blades and casing of gas leakage. Blades and gaipan joined by welding or riveting. Welded impellers of light weight, smooth runner. Small, medium pressure centrifugal fan impellers are made of aluminum alloy casting.