The smoke exhaust fire damper is installed on the smoke exhaust pipe. Its working principle is that when the fire smoke temperature in the smoke exhaust pipe exceeds 280 ℃, its fusible metal sheet condenses, and actively close the smoke exhaust fire damper to prevent the fire from spreading through the smoke exhaust pipe. The structure of fire damper is mainly composed of valve body and actuator. The valve body is composed of shell, flange, blade and blade connecting rod mechanism.

执行机构由壳体、叶片调度机构、离合器、温度熔断器等组成，防火阀执行机构通过金属易熔片和离合器机构控制叶片的滚动。当管路中的气体温度达到易熔金属片的冷凝温度时，易熔金属片熔化，芯轴上的紧固拉簧和拉簧销迅速使离合器底板断裂。

The actuator is composed of shell, blade dispatching mechanism, clutch, temperature fuse, etc. the fire damper actuator controls the rolling of blades through metal fusible plate and clutch mechanism. When the gas temperature in the pipeline reaches the condensation temperature of the fusible metal sheet, the fusible metal sheet melts, and the fastening tension spring and tension spring pin on the mandrel quickly break the clutch bottom plate.

此时，离合器和叶片调度机构分离，由于阀体上安装了两个变张力弹簧，叶片扭曲和滚动。由此可见，防火阀的执行机构采用机械传动原理，不需要电、气等动力，保证在任何情况下都能起到防火的作用。根据系统要求，当系统停用或正常运行时，防火阀开启。如果91视频成人网站中的气体温度低于所选金属易熔片的熔点，则防火阀处于正常工作状态，阀门打开。只要工作条件超过正常工作条件，阀门就会主动关闭以实现其功能。

At this time, the clutch and the blade dispatching mechanism are separated. Because two variable tension springs are installed on the valve body, the blades twist and roll. It can be seen that the actuator of the fire damper adopts the mechanical transmission principle and does not need electric, pneumatic and other power to ensure that it can play the role of fire prevention in any case. According to the system requirements, when the system is out of service or in normal operation, the fire damper will be opened. If the gas temperature in the pipeline is lower than the melting point of the selected metal fusible sheet, the fire damper is in normal operation and the valve is opened. As long as the working conditions exceed the normal working conditions, the valve will actively close to realize its function.