The K40l series mining main and auxiliary fan axial flow fans are a new product developed by the Ministry of Metallurgical Industry and the Mining Energy Conservation Promotion Station of China Nonferrous Metals Industry Corporation in the early 1980s. This product passed the ministerial level certification in 1984. It has unique advantages such as high aerodynamic efficiency, good matching of high-efficiency zones with mine ventilation networks, and significant energy-saving effects; The main air duct is equipped with a stabilizing ring anti surge device, and the characteristic curve has no hump, which can operate stably under any mine resistance; The blade installation angle is adjustable, the operating noise is low, and it can be directly reversed to reverse the wind; The simplest transmission structure adopts a direct connection between the motor and the impeller, with good overall stability, easy installation, easy maintenance, and low local resistance of the device; As the main fan, its installation requires minimal civil engineering work, which can save a lot of investment; It is suitable for installation underground and is an ideal fan for multi-stage ventilation systems.