What is a bimetal thermometer?

Bimetal thermometers are thermometers are temperature gauges that operate on the principle that different metals expand at different rates depending on the change in temperature. A bimetal thermometer consists of two different metal strips which have different thermal expansion coefficient. The metal two strips are bonded together forming the bimetal strip.

Bimetal thermometers are used in many applications, typically on boiler systems but are used in other HVAC applications as well as a variety of other industrial applications.

How does a bimetal thermometer work?

When the temperature rises and falls, the different metals expand and contract to different degrees, which leads to a deformation of the bimetal strip which is in the form of a helical or spiral tube, this mechanical deformation is converted into a rotary movement. This movement is transferred to the pointer shaft and moved the pointer on the dial face measuring the temperature.