Both optical pyrometer and photoelectric colorimetric pyrometer are non-contact temperature measurement instruments. In this article, Changhui Meter will introduce the working principle, advantages and disadvantages of optical pyrometer and photoelectric colorimetric pyrometer.

The optical pyrometer is one of the earliest and most widely used non-contact thermometers. It has simple structure, convenient use, wide temperature measurement range (700-3200℃), and generally meets the accuracy requirements of industrial temperature measurement. Optical pyrometer is currently widely used for temperature measurement of high-temperature melts and furnaces. It is a very important high-temperature instrument in metallurgy, ceramics and other industrial sectors. The optical pyrometer is made using the principle that the intensity of the monochromatic radiation of the heated object increases with the increase in temperature. Because it uses a single wavelength for brightness comparison, it is also called a monochromatic radiation thermometer. Objects will emit light at high temperatures and have a certain brightness. The brightness of the object is proportional to its radiation intensity, so the brightness of the heated object reflects the temperature of the object. Usually the brightness temperature of the measured object is obtained first, and then converted into the true temperature of the object.

The disadvantage of the optical pyrometer is that it is observed by the human eye and needs to be manually balanced, so it cannot achieve rapid measurement and automatic recording, and the measurement results are subjective. Recently, due to the development of photodetectors, interference filters and monochromators, the status of optical pyrometer in industrial measurement has gradually declined, and it is being replaced by more sensitive and accurate photoelectric pyrometers. The photoelectric pyrometer is developed on the basis of the optical pyrometer, which uses photosensitive elements instead of human eyes to realize photoelectric automatic measurement.