The working principle of the bimetal thermometer is based on the principle of solid thermal expansion, welding two pieces of metal with very different expansion coefficients together. When the temperature changes, the very different expansion coefficients cause different expansion and contraction, resulting in bending deformation of the metal sheet. Different amounts of rotation are generated according to different deformations, and the amount of rotation drives the connected shaft and the indicator needle at the other end to indicate the temperature.

The bimetal thermometer is an instrument that can directly measure the temperature of the medium and low temperature field, and the temperature measurement range can be selected within -40 ~ 550C. Its mechanical principle has the characteristics of safety, mercury-free, good anti-corrosion performance and long life. Industry is generally applicable to industrial equipment on the pipeline temperature measurement, involving HVAC, pharmaceutical, food, petroleum, chemical and other industries. Household aspects are generally suitable for measuring the temperature of food, or indoor temperature measurement, common use occasions are oven, hand coffee, fried steak, soup, sugar and so on.