Such structures, in turn, are divided into axial, roof, radial and channel. We emphasize that all products are divided into ordinary and heat -resistant. The usual can withstand the heating temperature of 800 degrees Celsius and, often used in places of high humidity, have high corrosion resistance. Heat -resistant products are used for gas or air and withstand heating up to 2000 degrees Celsius. For dusty air, airwear structures are widely used, such fans can withstand even strong fires, as they withstand the temperature of up to 6000 degrees Celsius.