The working principle of infrared temperature measurement is to collect the infrared radiation energy of the target object in its field of view through a special optical system of the thermometer. The infrared energy is focused on the photodetector and converted into the corresponding electrical signal, which is converted into the temperature value of the measured target. The high-temperature infrared thermometer PT300＼PT300E is an ideal instrument in the processing industry such as casting, forging, and heat treatment. It has a high optical resolution of 80:1 and can measure the surface temperature of high-temperature objects at a distance. For example, the furnace temperature is measured through the vaults of high-rise buildings and fire walls, and the surface temperature of the rejuvenating furnace chimney, or the temperature of melted substances in the combustion chamber.Also， it can assess the extent of brick damage.