The DWT-I axial flow roof fan has a large air volume and lower pressure than the centrifugal fan. It can be designed as a bidirectional rotating reversible fan according to user needs. This fan has the characteristics of low noise, light weight, smooth operation, high efficiency, and good anti-corrosion performance. Suitable for indoor ventilation and air exchange in mechanical factories and warehouse buildings such as petroleum, chemical, textile, and metallurgical industries.