Centrifugal fans can transport air and other gases that are non-flammable, stable to human performance, and non-corrosive to steel. The gas must not contain viscous substances, and the dust and hard particles contained should not exceed 150 mg/m3. The gas temperature must not exceed 80°C. This blower features excellent aerodynamic performance, stable operation, minimal vibration, high efficiency, and a long service life. It is available in four structural types: a, b, c, and d. This fan is widely suitable for indoor ventilation in industrial and mining enterprises, large buildings, hotels, restaurants, and more.