This series of fans may be extensively applied to the air conditioning project of industrial and mining enterprises, guesthouses, hotels, museums, gyms, air conditioning, textile, shipping, civil buildings, etc. They are applicable most to the pipeline pressurization, air blowing and exhaust, and ventilation of high-rise and common buildings. The gas to be delivered excludes inflammable, explosive and corrosive gas. The temperature of delivery media shall not be more than 80℃. And the content of dust and solid sundries shall not be more than 150mg/m3.