Damper 280 degrees at high temperatures must be closed Tianjin damper, it is a signal back to the controller via the input module damper making, then control exhaust fan stops. To prevent the fire from spreading to other fire district through exhaust pipes. On the exhaust fan inlet manifold should be set when the flue gas temperature exceeds 280 ℃ can turn itself off when the smoke damper and exhaust fan should Shandong valve interlock, so when the flue gas temperature exceeds 280 ℃ exhaust pipe closed on their own, to prevent smoke spread to other parts. Otherwise, close only exhaust fan, can not prevent the spread of smoke and fire through the pipeline. An air flow control valve: 2 structural principle three technical parameters 64,654,132 6,341,321,356 444444444444444444 21521 Hebei exhaust fan, ventilation equipment Plumper (certified), the damper is provided by Dezhou Plumper ventilation plant. Dezhou Plumper ventilation plant (www.frtfsb.com) (www.frtfsb.com) is a leader in 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.