Fan is China's customary abbreviation for gas compression and transmission machinery. Generally speaking, fan includes ventilating fan, blower and wind turbine. Gas compression and gas conveying machinery is the machinery that converts the rotating mechanical energy into gas pressure energy and kinetic energy, and transports the gas out. The main structural components of the fan are impeller, casing, air inlet, bracket, motor, pulley, coupling, muffler, transmission parts (bearings), etc.