I. Characteristics

1.Various models, large application scope: 2 models are available according to different pressures, air flow and noise requirement:

a. Axial roof fans: model DWT－Ⅰis for medium and low pressure, large volume condition. Its design can be changed into dual-reversible type with the same efficiency (national patent).

b. Centrifugal roof fan: two models: DWT-Ⅱ and DWT-Ⅲ. It is applied to provide high pressure while low air volume. 

2.High-efficiency, low-noise: This series uses CAD software, after optimizing design and research, its design has been rewarded patent of utility model and national outstanding patent. Its design adopts different rotate speeds, angles and impellers with the same diameter to satisfy different conditions. In this way, the fans match with the whole system and save energy and bring down noise.

3.Light, high-strength, corrosion-resistant: The impeller has different material types for various mediums, which encompasses ABC (engineering plastics), FRP (glass fiber reinforced plastics) and aluminum alloy sheet. The centrifugal fans are applied for high pressure conditions and the surface of impellers is galvanized & plastic sprayed, lowering its weight and enhancing its corrosive resistance. 

4. Stable operation, long-term service: little inertia, precise balance, stable operation make the fan's performance standard higher than its competitors. 

5.Large applying scope: This series fans can be made into explosion-proof, retardant, anti-aging type, etc., for ventilation of the conditions of flammable, explosive and corrosive air .

6.Elegant appearance: The rain cover is made of FRP with external surface of imported resin film. Its curve is smooth, elegant and practical. It can also be modified by plastic sprayed (PVC) after galvanization.    

7. Applying condition: The medium shall not exceed 60℃. No adhesive drifts, no exceeding 100 mg/m3 dust in the air. As for the high temperature medium, we provide fire-fighting exhaust fans (national patent) for the roof fans.

II. specification of models

（1）The axial roof fans have 17 models of Φ300~ Φ1800mm with the diameter varies fromΦ300 to Φ1000mm of 9 models. We can provide other models for the clients' different requirement.

(2) The structure of the fans refers to the whole installation drawing. This series of fans consist of impellers, ducts, rain cover, driving components, loose-leaf air doors and safety net.

(3)Driving type: DWT-I model Φ≤2200 mm, of motor directive drive. If belt drive is needed, our company also can satisfy this demand. Because its extensive use and large quantity, its structure varies too. We can research, design and improve the external structure of them in conformity of customers' different technical parameters.

（4）If the exhaust air pressure exceeds 600Pa, the centrifugal or centrifugal axial fans shall be installed. Pressure between 400Pa-600Pa, mixed flow fan should be chosen. Pressure below 400Pa, axial fans should be applied.