Electric kettles have been used in many households and are often seen in hotels. The electric kettle is very convenient to use. Load tap water, press the switch, and the water will automatically cut off after the water boils. The ability of the electric kettle to cut off automatically depends on a material called bimetal.
1. Substances generally have the characteristics of thermal expansion and contraction, especially metals, but different metals have different expansion coefficients. After raising the same temperature, some metals have obvious changes in thermal expansion, and some metals have no obvious changes.
2. If a special fusion process is used, two metal sheets with different expansion coefficients are fused together, and they will bend in one direction when heated and expanded, which is called bimetallic sheet.
3. Install the bimetal in a temperature-sensitive place. When the water temperature in the kettle reaches 100 degrees, the bimetallic sheet bends to such an extent that it pushes some mechanical transmission parts, forcing the switch to open and cutting off the circuit.
4. The bimetal strip has low cost and high reliability, and is widely used in rice cookers, ovens, air switches and other occasions where the temperature control circuit needs to be disconnected.
Depending on the actual use, there are three or more metal fusion materials, which we still habitually call bimetallic sheets.
