Kitchen is generally recommended to use a centrifugal fan. Centrifugal fans also points to a multi-leaf front and rear wheel to wheel. Before comparing the advantages of the impeller to the impeller and after :() opt for a lower speed (low noise), smaller diameter can get a larger air volume total pressure. Forward impeller drawbacks: low efficiency, high energy consumption, easy cleaning cleaning. After the impeller advantages: high efficiency, energy saving, easy cleaning cleaning. After drawback compared to the impeller to the impeller) to get the same amount of wind and the total pressure required for high speed (and therefore noisy), and a larger diameter before :(. Fan selection: calculate the required static pressure fan duct according to the situation: the cross-sectional area of ??the duct is determined according to the amount of wind and wind speed (wind speed 10-15 m / s or so). Duct aspect ratio should not exceed 2: 1 (in order to save material and reduce the drag). According to the wind speed, the wind pipe cross-sectional area, elbows, reducers, etc. to calculate the drag (ie, the required fan static pressure). According to the calculated air volume, static pressure. Select the appropriate fan. Two-speed exhaust fan temperature exhaust fan, air conditioning dual benefit trusted (authenticated), Shijiazhuang dual exhaust fan is provided by Carrier Air Conditioning Equipment Co., Texas. Carrier Air Conditioning Equipment Co., Texas two (www.slktsb.com) is a leader in Dezhou, fans, ventilation equipment, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. Two-profit leader in air conditioning with the staff warmly welcome all inquiries negotiations to create a better conditioned double benefit in the future.