Bimetal thermometers measure temperature by contact and non-contact methods. The methods and methods of contact temperature measurement and non-contact temperature measurement are different. One is related to the measured medium and the other is irrelevant. The temperature measurement contact temperature measurement principle of the bimetal thermometer is heat balance, but the non-contact temperature measurement is to measure the temperature of the object by using the principle that the heat radiation energy of the object changes with temperature.
Contact temperature measurement and non-contact temperature measurement have their own advantages, but also have their own different deficiencies. For example, the value of the contact temperature measurement is accurate, but it must be in contact with the medium and it will be corroded by the medium. The other temperature measurement will not be corroded by the medium, but the measurement accuracy is not very accurate. However, it can measure the upper limit of the temperature and is usually used to determine the temperature of the surface of a high temperature object. Below we will introduce in detail the two methods of temperature measurement and comparison of advantages and disadvantages of bimetal thermometer.