Features 1, DWT-II type, DWT-III type centrifugal roof ventilator is suitable for smaller air volume and pressure requires high; 2, high efficiency and low noise of the fan series uses advanced CAD Series software, the multi-target Optimization of design and development. This series of fans in 1200,1400,1500,1600,2000,2200, and 2400mm diameter fan with different speeds with different angles to change several volume, pressure way to meet the needs of different use conditions, to match fan and systems to facilitate energy-saving and noise reduction. 3, light weight, high strength, corrosion resistance: working air fan impeller according to different corrosive media and the use of different materials, respectively, ABS (plastic) FRP (GRP) and aluminum materials, for high pressure fan greater speed centrifugal fan impeller surface is galvanized plus special spray corrosion outside the grounds, not only reduces the overall weight and has good corrosion resistance; 4, smooth operation and long life; rotational inertia of the turbine can be small ; balancing high precision, smooth operation, the factory internal control standards require that the performance indicators were higher than the fans of professional standards, to ensure long-term stable operation of the fan; 5, wide application: The fan can be used according to requirements made into explosion-proof retardant type, suitable for anti-aging, pumping flammable and corrosive gases occasions; 6, good looks: The fan fiberglass hood parts production, the appearance of imported glue agriculture resin film surface over soft, beautiful generous, practical; also be made of galvanized steel hood spray (PVC) processing according to user requirements; 7. Conditions: medium temperature does not exceed 60 ℃, the gas must not contain excess goo, dust content of less than 100mg / m. For medium temperature of the occasion, the company has high-temperature turbine technology available products. 8, the product of Zhejiang Province by the technical supervision of qualified testing products, test items including flame retardant, conductive properties, explosion, wind performance with City Product Technical Supervision. First, the model structure of 1, the centrifugal roof fan diameter Φ300-Φ1000mm nine kinds of machine numbers; 2, the fan impeller, hairdryer, hood, transmission parts, loose-leaf damper, put the bird nets, safety nets and other components; 3 roof wide range and large number of fans, according to the form required use of complicated structure, the company may be technical requirements of different users, for research and development, improve the structure and appearance. Second, the blower fan size diameter: 690-1840mm air volume: 1450--56900m3 / h Pressure: 62-322pa