Measuring principle of Bimetallic thermometer

Measuring principle of Bimetallic thermometer

The WSS series Bimetallic thermometer work on the principle that two different metals expand at different degrees when the temperature changes.

In order to improve the sensitivity of temperature measurement, Bimetallic thermometer usually make metal sheets into a spiral shape. When the temperature of the multi-layer metal sheet changes, the amount of expansion or contraction of each layer of metal varies, causing the spiral coil to roll up or loosen.

Since one end of the spiral coil is fixed and the other end is connected to a pointer that can rotate freely, when the bimetallic sheet feels a temperature change, the pointer can indicate the temperature on a circular graduation scale. The temperature measurement range of this kind of instrument is -80~500℃, and the allowable error is about 1% of the two steps of the scale.

The main component of an industrial Bimetallic thermometer is a multilayer metal sheet composed of two or more metal sheets laminated together.

The purpose of this kind of thermometer is similar to that of a rod-shaped glass liquid thermometer, but it can be used under conditions that require higher mechanical strength.