rooftop fan,good structure, large air volume, used for factory etc, FRP material the base cast iron, light weight. 3 The roof fan is mainly composed of the paddle-wheel wind tube,nozzle button,motor and other fittings,The main technical parameters:No. 5Impeller diameter 500mmWind 6400-7000m3/hTotal Pressure 131-113Speed 960r/minWeight 30kg3 The roof fan is mainly composed of the paddle-wheel wind ...