A fire damper is a type of temperature control using a shape-memory alloy, which closes through the force of gravity and a spring mechanism. The new products also feature a design that uses the shape-memory alloy to deform and close the valve. Fire dampers are installed on the supply and return air ducts of ventilation and air conditioning systems, typically in an open state. During a fire, when the gas temperature in the pipes reaches 70°C, the fusible link melts and the valve closes automatically under the force of the torsion spring, meeting fire resistance and integrity requirements for a certain period of time, and serving as a smoke and fire barrier. When the valve closes, a shutdown signal is output.