Do you know about the double metal surface thermometer?

Double thermometer on the surface of the metal material: SS304 stainless steel shell, aluminum table card, behind the magnet. It is to rely on the double metal heat bilges cold shrink principle of sensors to work, by contact spring or magnet at the bottom of the thermometer to measure the metal surface and reading. This kind of surface of the bimetallic thermometer measurement range can be from 0 c to 500 c, accuracy can be + / - 3 ﹪. For some of the requirements for accuracy is not high occasions, the use of thermometer of cheap is a money and beauty. It is important to note: surface thermometer can't adsorption on the stainless steel material, must pay attention to surface temperature sensor is installed, it will determine the surface temperature measurement of accurate or not. In addition, when using, pay attention to clean up and check, regularly test the measured values. Surface thermometer has been widely used in machinery, metallurgy, energy and defense departments and so on. For example: heat treatment of castings, forgings, gas pipes, steam pipes, wall of the furnace and other metal surface temperature measurement.