This series of fans with high efficiency, low noise, smooth pressure curve, using a wide range of features, mainly for industrial enterprises, stadiums, theaters, basements, the size of hotels, restaurants, shopping centers and large buildings indoor ventilation, exhaust, for gas, dust and other cooling purposes, but also with other types of mechanical equipment for gas recycling. The transmission medium is air and other non-spontaneous, harmless, non-corrosive gases; B4-72 explosion-proof motors, ventilation of flammable volatile gases can be used as the ventilation gas temperature ≤800C, are not allowed inside the gas viscous substances, dust and impurities fixed ≤150mg / m2.