Under normal circumstances, the exhaust should first cut off the air supply local reporting, so the combustion air fan, but in accordance with the "high level of civilian health plan made nuisance fire standards" (GB50045-95,2001年版) and in Article 8.4.11 "Libraries car repair garage, brakes library planning hinder fire standard" (GB50067-97) defined in 8.2.7, the senior civilian health set up machine-made underground chamber and exhaust of cars library without directly dispersed to the outside Chu mouth hinder fire partition, when setting machine exhaust system, Hou set air system should be the same time. Air system blower and send damper linkage fire should start to produce a positive pressure area, smoke exhaust before signing out. Two-speed exhaust fan and exhaust mechanical electron source shall request the fire power supply. Performance exhaust fan; fire exhaust fan, said during use, not only to make the appropriate use and maintenance work, and to its performance fully displayed, exhaust fan prices, improve efficiency fan, so as to increase Its range of applications, the majority of user acceptance. So we should make energy-efficient exhaust fan fire effect on how full performance of it, today as we detail below: For some relationship between the different flows, we adjust the way is also divided into several different approaches, Fuzhou smoke fan, that adjustment method has little effect on energy savings, even not only energy saving, but because of the presence of adjusting means more power consumption. Variable-speed control curve closer to the ideal curve. Therefore, the variable-speed control mode is superior, especially the use of variable frequency motor speed control of energy-saving program is the best, but the need for additional frequency devices. About two-speed motor; two-speed motor is an asynchronous motor pole-changing speed is reached to change the number of pole pairs of the stator rotating magnetic field of the stator winding is connected by changing the method, thus changing the motor speed. According to the formula; n1 = 60f / p known asynchronous motor synchronous speed and inversely proportional to the number of pole pairs, doubling the number of pole pairs, exhaust fan maintenance, synchronous speed down to half speed n1, the motor rated speed n will also fall approximately half of the exhaust fan principle, a change of pole pairs can achieve the purpose of changing the motor speed. This level of speed control method is not smooth speed control, and only applies to squirrel cage motors. Exhaust fan applications, Chen Yu-conditioned (certified), exhaust fan Fuzhou City by Wu Chen-yu air-conditioning Limited. Wu Cheng Chen-yu air-conditioning Co. (www.wccykt.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 . Chen Yu-conditioned in leadership with the staff warmly welcome all inquiries negotiations to create Chenyu air conditioning better future.