In the following circumstances ventilation, air-conditioning duct system should be set damper: (1) pipeline crossing the wall of the fire district; (2) pipeline crossing ventilation, air conditioning and major engine room fire hazard or a large room Partition walls and floor at; both sides (3) vertical and horizontal pipe duct duct junction of each level (4) pipeline crossing movement joint. Matsubara damper. Automatic smoke damper (Metro Engineering) Fire subway ventilation and air conditioning systems, exhaust valve having automatic fire alarm equipment and gas extinguishing system linkage control functions. Fixed fire dampers. Each automatic smoke dampers with two independent electric control signal, respectively, by EMCS, gas consumption system to monitor, control signals are DC24V ± 10% signal. Each automatic smoke dampers have six independent feedback signal (three open place, three off place) feedback signals are normally open dry contact signal. Zhuhai damper, Yanda air conditioning (certified), Matsubara damper by Wu County Yanda air-conditioning plant. Wu County Yanda air-conditioning plant (www.wcydkt.com) (www.wcydkt.com) Shandong Dezhou, heat, refrigeration and air conditioning equipment leader, over the years, the company is implementing the scientific management, innovation and development, honesty and trustworthiness policy, and satisfy customer needs. In Yanda air conditioning leadership with the staff warmly welcome all inquiries negotiations to create Yanda air conditioning better future.