Exhaust system used for the basement, large shopping malls, large fire district, long corridors, as well as under natural draft conditions can not meet their needs plus mechanical exhaust system. Opening plus exhaust valve exhaust port form, plate electric exhaust port forms can also be normally closed. Fans can be used in conjunction with underground diversion. Basement, to be used in conjunction with the makeup air equipment. Due to limitations in the basement by the subsurface conditions and space, to meet the air flow and pressure conditions and other parameters, the fire's smoke exhaust ventilation systems and usually can be combined, so we use the two-speed fan in the underground garage, That is the same fans and the same duct. Under normal circumstances, the fan runs at low speed as exhaust ventilation use, when a fire, fans immediately becomes the high-speed operation cf type kitchen exhaust duct fans, used as a fire exhaust fan. Such a machine with two two-speed exhaust fan, not only to reduce the construction cost, space saving, more importantly, greatly improves the efficiency and reliability of the equipment. If the exhaust and smoke control systems are completely separate sets of roof exhaust fan, exhaust fan and just put the fire when the fire runs, rarely used, then the failure is difficult to be found in a timely manner and get access row Smoke fan, but when the real fire, but also difficult to ensure a smooth and put into use. The two-speed fan just to overcome this shortcoming, usually as an exhaust fan running, the problem can be found in time and get the repairs, and always in a good state of readiness. Two-speed exhaust fan, Chen Yu-conditioning (certified), Wuqing exhaust fan provided by Wu Cheng Chen Yu Air Conditioning Equipment Co., Ltd. Wu Cheng Chen Yu Air Conditioning Equipment Co., Ltd. (www.wccykt.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 . Chen Yu-conditioning in leadership with the staff warmly welcome all inquiries negotiations to create Chenyu conditioning a better future.