First, the product description is an efficient low-pressure axial fan fan, low power consumption, low noise, corrosion resistance, widely used in industrial, commercial buildings, motor and impeller directly connected to the body shell into a barrel, along the direction of rotation clockwise. 5-11-type axial fan is designed to replace 30K4 products, T35 and T40 for similar foreign products were analyzed and compared by the model-level experimental study to determine the fan-shaped and cylindrical Sunda hub structure, improved motor design on the structure reduces the flow losses, thus the fan efficiency to 89.5%, the noise level reduction than A 3.6dB, but also enhance the strength of the blade root, avoiding the blade breakage, fans of the series is the fan energy group in 1985 jointly designed products. This series of fans for conveying non-flammable, explosive, non-corrosive, non-significant dust gas, its temperature must be over 60, it is widely used in general factories, warehouses, offices, residential heating ventilation or heat strengthening of with. Can also be a longer interval of the exhaust duct installed in series, to increase the pressure in the pipe. Chemical ventilation FT35-11 type axial fans used as preservative containing corrosive gases. BT35-11 explosion-proof axial fan can be used as a place containing flammable ventilation. BFT35-11 type corrosion proof axial fans for corrosive chemical and mine enterprises flammable or explosive gas.