一般设在通风空调管路穿越防火分区处。平时开启，火灾时关闭以切断烟、火沿通风管道向其他防火分区蔓延。 1、由安装在阀体中的温度熔断器带动阀体连动机构动作的防火阀。该温度熔断器的易熔片或易熔环熔断温度70℃，这类防火阀用的最多。 2、由设在顶棚的温感器联动的防火阀。该类阀门国内使用较少。 3、由设在顶棚的烟感器联动的防火阀。该类阀门通常又称为防烟阀。根据工程需要，有的防火阀上既设有温度熔断器又与烟感器联动，这类阀门称为防烟防火阀。 70℃防火阀用在空调送风、通风系统管道上；平时常开，发生火灾时关闭，联锁风机，使风机关闭；280℃防火阀用在排烟系统管道上，平时常开，发生火灾时排烟，当烟气温度达到280度时，防火阀关闭，联锁风机关闭；280℃防火阀应为常开，又叫高温防火阀，一般安装在有高温环境的通风管道中，当温度到达280℃后易熔合金熔化，阀门关闭，同时可以用24V电信号控制。如果说是280排烟防火阀应为常闭，安装在排烟管道中发生火灾时控制中心给出电信号使其打开排烟，当温度到达280时易熔合金熔化阀门关闭，是一种二次动作的阀门。通风管是火灾时不使用的，到70℃时关闭防火阀起到阻止火灾蔓延的作用。排烟系统的防火阀是在火灾是排烟的，烟气温度较高，到280℃时，这个火灾通过机械排风已经达不到效果了，排烟阀关闭防止风机等设备损坏。70℃防火阀常开，防火常开；遇火关闭。排烟防火280℃常闭，遇火打开，开始排烟；当空气气流到280℃关闭。
Fire damper is a type of valve which is controlled by the temperature of fusible alloy and closed by the action of gravity and spring mechanism. Some of the new products use memory alloy to produce deformation to close the valve.
It is generally set at the place where the ventilation and air conditioning pipeline passes through the fire compartment. Open at ordinary times and close in case of fire to cut off the smoke and fire spreading along the ventilation pipe to other fire zones. 1. The fire damper is driven by the temperature fuse installed in the valve body to move the valve body linkage mechanism. The fusible link or fusible ring of the temperature fuse has a fusing temperature of 70 ℃, which is the most commonly used type of fire damper. 2. The fire damper is linked by the temperature sensor on the ceiling. This kind of valve is seldom used in China. 3. The fire damper is linked by the smoke detector on the ceiling. This kind of valve is also known as anti smoke valve. According to the needs of the project, some fire dampers are equipped with temperature fuses and linkage with smoke detectors, which are called smoke and fire dampers. 70 ℃ fire damper is used on the air supply and ventilation system pipes of air conditioner; normally open, close in case of fire, interlock the fans to make the fans close; 280 ℃ fire damper is used on the smoke exhaust system pipes, normally open, smoke exhaust in case of fire, when the smoke temperature reaches 280 ℃, the fire damper is closed, and interlock the fans are closed; 280 ℃ fire damper shall be normally open, also called high temperature fire damper, generally It is installed in the ventilation pipe with high temperature environment. When the temperature reaches 280 ℃, the fusible alloy melts and the valve is closed. At the same time, it can be controlled by 24V electric signal. If the 280 smoke fire damper is normally closed, the control center will give an electrical signal to open the smoke exhaust when the fire occurs in the smoke exhaust pipe. When the temperature reaches 280, the fusible alloy melting valve is closed, which is a kind of secondary action valve. The ventilation pipe is not used in case of fire, and closing the fire damper at 70 ℃ can prevent the fire from spreading. The fire damper of smoke exhaust system is used to exhaust smoke in case of fire. The temperature of smoke is high. When the temperature reaches 280 ℃, the fire can't reach the effect through mechanical ventilation. The smoke damper is closed to prevent the damage of fans and other equipment. 70 ℃ fire damper is normally open, fire protection is normally open; it is closed in case of fire. Smoke and fire protection: normally closed at 280 ℃, open in case of fire, start to smoke; when the air flow reaches 280 ℃, close.