Alloys of certain metals such as Ni-Ti and Ni-Ti-Cu can memorize shape, so that even if it is deformed, it exhibits the property of returning to its original shape as a result of temperature changes.
A shape memory alloy spring is used as a temperature control valve in water mixing valves by utilizing the properties of shape memory alloy.
Can be used for fire dampers that close ventilation ducts in the event of a fire, the shape memory alloy spring shrinks when the hot air is sensed and the butterfly valve closes.
A shape memory alloy spring is used in a valving element which prevents the flow of hot water into a hollow fiber filter.