Centrifugal fan is to rely on the input of mechanical energy, increase the gas pressure sending gas machinery side by side, it is a follower of fluid machines. Centrifugal fans are widely used in factories, mines, tunnels, cooling towers, vehicles, ships and buildings, ventilation, dust and cooling ventilation of boilers and industrial furnaces and air air conditioning equipment and household appliances and equipment for cooling and ventilation; grain drying and organization; wind tunnel air and hovercraft inflatable and push, and so on.