Ventilation ducts are mainly used in industrial and construction projects, the application areas are mainly involved: the clean room of the clean room for the electronics industry, the clean room for the medical and foodstuffs workshop, hotels, shopping malls, factories and office air conditioning systems, industrial pollution control Dust, smoke, oil and other exhaust pipe, industrial environment or post comfortable with air duct, coal mine gas drainage gas drainage system, coal mine environmental control with the return air system ... and so on;