280 smoke damper fire damper and other nature is the same, only more sensitive to temperature. 280 damper usually was always open damper 70 ℃, smoke detector control center sent an electrical signal (DC24V) fire, motor-energizing action within the circle damper actuator, the valve automatically shut down, and shut down electrical output. After the valve actuation DC motors driving the reset, the valve can be manually shut down or 70 ℃ melting following action closes the valve has a six-speed adjust the air flow opening. Product Principle: Edit installed in the central air-conditioning duct systems damper factory, works easily fluxing temperature control, by the action of gravity and spring mechanism closes the valve. When a fire occurs, the fire invaded the duct dampers, high temperature causes the fusible alloy melting on the valve, or to memory alloy deforms the valve automatically closes, and the fire district for duct dampers occasions throughout the plant, rich ventilation equipment (certification), fire dampers supplied by Dezhou rich ventilation plant. Dezhou rich ventilation plant (www.frtfsb.com) (www.frtfsb.com) is an industry leader in Shandong Dezhou, fans, ventilation equipment, over the years, the company implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, the maximum Limits to meet customer needs. Rich ventilation equipment in leadership with the staff warmly welcome all inquiries negotiations to create rich, ventilation a better future.