Tunnel fans are also called tunnel jet fans, tunnel fans, jet fans, and are widely used in practical use of tunnels such as water conservancy dam projects, highways, railways, and subways. The new type of high-efficiency and energy-saving tunnel fan FD, both ends can be equipped with mufflers, and the noise can be controlled within 80 decibels According to different ventilation resistance requirements, the FD tunnel counter-cyclone press-in fan can be used as a whole or in stages, thereby reducing ventilation power consumption and saving energy. If the tunnel length is less than 2000m, it can supply air normally without moving the fan, which reduces the labor intensity of workers and saves ventilation time. It is an ideal equipment for tunnel ventilation.