Resistance thermometer. It is composed of thermal resistance and its matching display instrument. The thermal resistance element is made of the characteristic that the resistance value of metal (or semiconductor) changes with temperature. Therefore, the change of temperature can be measured by measuring the change of resistance. Platinum thermal resistance (graduation number is Pt100) can be used to measure the temperature in the range of -200 ~ 650 ℃ in industry. In addition to the advantages of thermocouples, it also has the advantages of high measurement accuracy in the low temperature range, so it is more widely used in the low temperature field. It is used for low temperature measurement in the cold storage box in the large air separation plant.
4) Pressure gauge thermometer. It is made by using the principle that the pressure of the gas (or vapor, liquid) in a sealed container changes with temperature. When measuring the temperature, insert the temperature bulb into the measured medium. When the temperature changes, the pressure of the gas (or vapor, liquid) in the temperature bulb changes, and it is transmitted to the elastic pressure gauge through the capillary, and the temperature change can be measured according to the pressure change. It can measure the temperature in the range of -100～600℃. The wTZ-288 electric contact pressure thermometer is commonly used in large air separation equipment. The measuring range is 0～100℃. It is used to measure the lubricating oil temperature.
