The fan is mainly composed of impeller, casing, inlet collector, guide vanes, electric motor and other components. The impeller is welded onto the hub using a twisted flat plate with meridian acceleration characteristics. After dynamic balance verification and overspeed test, it has good aerodynamic performance. The casing adopts a circular shape and is connected as a whole with a soundproof fan. The outlet is equipped with flow deflectors, which have good airflow distribution and stable pressure.