What is the function of fire smoke exhaust sealing valve?

Fire-fighting smoke exhaust and fire-proof sealing valve is mainly installed at the entrance of smoke exhaust fan, at the smoke exhaust port or when crossing the fire zone, to control the fire to automatically close once it reaches a specific temperature of 280 degrees, because it is close to the ignition point of 292 degrees, which is basically a spark or flame, and smoking at this time is meaningless, so its main function is to control the corresponding smoke exhaust port or the part outside the fire zone to ensure that other parts continue to smoke.