Performance introductionThe axial-flow fans of Type T35-11, BT35 and FT35 is a replacement of Type-30K4 products. Base on the analysis and comparison with the foreign similar products abroad, Type-T35 has optimized the design of its fan impeller structure, improved its motor design and reduced the flow loss of its structrue, thereby the efficiency of its air blower has been inc-reased by 89.5% as well as the noise level decreased by 3.6dB than rate A, and its enhanced strength of root fans has also prevented effectively from blade fractrue. The fans of this series are applied to transfer the non-flammable and non-explosive gas without corrosion and obvious dusts, with its temper-ature lower than 60°C. It is widely used for ventilating or increasing hea-ting emission in normal factories, storages, offices and houses. Its interval installation in vent pipes can increase pressure in the pipe. BT35-11 is an explosion-proof axial-flow fan used for the ventilation of flammable gas, explosive gas and other escaping gas. FT35-11 is an anti-corrosion axial-flow fan, used for corrosive gas delivery, with its functional parameters same to that of T35-11.