Determined in accordance with the exhaust fan air flow and wind speed (wind speed 10-15 m / s or so) duct cross-sectional area. Duct aspect ratio should not exceed 2: 1 (to save material and reduce the drag). Wind speed, wind pipe cross-sectional area, elbows, reducers, etc. to calculate the drag (ie fan static pressure required). Can not claim senior civil use of variable speed or multi-speed drive form, exhaust fan specifications to achieve in one machine (that usually use through ventilation and fire temperature exhaust) aims at rated speed, smoke Fans offer, in the work area, Cangzhou exhaust fan, fan pressure curve measured with the description given in the curve should meet the following requirements: axial-flow exhaust fan at a predetermined flow rate, corresponding to the pressure deviation of ± 5%. Centrifugal exhaust fan at a predetermined flow rate, corresponding to the pressure deviation of ± 5%. A sound level than the noise limits should be consistent with exhaust fan in the specification given operating point under the JB / T8690-1998 provisions of exhaust fan Model | l Rui Electric (Online) | Cangzhou exhaust fan by the liter Swiss mechanical and electrical equipment plant to provide ventilation and air conditioning. L Rui HVAC Electrical Equipment Factory (www.dzsrxfkt.com) is an industry leader in Shandong Dezhou, fans, ventilation equipment, over the years, the company implement the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. In liters Swiss electromechanical leadership with the staff warmly welcome all inquiries negotiations to create liter Swiss electromechanical better future.