Advantages and disadvantages of non-contact temperature measurement instruments

Non-contact temperature measuring instruments are designed based on the principle of thermal radiation of objects. During measurement, the temperature sensing element does not come into direct contact with the object being measured. It is usually used to measure the temperature or surface temperature of high-temperature objects above 1000℃ that move, rotate or react quickly.

Its advantages are:

(1) Wide temperature measurement range (theoretically, there is no upper limit), suitable for high-temperature measurement;

(2) The temperature field of the object being measured is not destroyed during the temperature measurement process, and the original temperature field distribution is not affected;

(3) The temperature of moving objects can be measured;

(4) Small thermal inertia, short detector response time, fast temperature measurement response speed, about 2-3s, easy to achieve fast and dynamic temperature measurement. Under certain specific conditions, such as nuclear radiation field, radiation temperature measurement can be accurately and reliably measured.

The disadvantages of non-contact temperature measuring instruments are:

(I) It cannot directly measure the true temperature of the object being measured. To obtain the true temperature, emissivity correction is required. The emissivity is a parameter with quite complex influencing factors, which increases the difficulty of processing the measurement results.

(2) Because it is non-contact, the measurement of the radiation thermometer is greatly affected by the intermediate medium. Especially under industrial field conditions. The surrounding environment is relatively harsh, and the influence of the intermediate medium on the measurement results is greater. In this regard, the choice of the wavelength range of the thermometer is very important.

(3) Due to the complexity of the principle of radiation temperature measurement, the thermometer has a complex structure and a high price.

Non-contact temperature measuring instruments mainly include radiation thermometers, fiber optic radiation thermometers, etc. The former is further divided into full radiation thermometers, brightness thermometers (optical pyrometers, photoelectric pyrometers) and colorimetric thermometers. (end)