Reasons why infrared thermometers are inaccurate
1. The relationship between the temperature measurement target size and the temperature measurement distance
At different distances, the effective diameter of the measurable target is different, so pay attention to the target distance when measuring small targets. The definition of the distance coefficient K of the infrared thermometer is: the ratio of the distance L of the measured target to the diameter D of the measured target, that is, K=L/D.
2. Select the emissivity of the measured substance
Infrared thermometers are generally graded according to black bodies (emissivity ε=1.00), but in fact, the emissivity of substances is less than 1.00. Therefore, when the real temperature of the target needs to be measured, the emissivity value must be set. The emissivity of matter can be found from "Data on emissivity of objects in radiation thermometry".
3. Measurement of targets in strong light background
If the measured target has a bright background light (especially when it is directly illuminated by sunlight or strong lights), the accuracy of the measurement will be affected. Therefore, objects can be used to block the strong light directly hitting the target to eliminate background light interference.
4. Other reasons
1) Only the surface temperature is measured, and the infrared thermometer cannot measure the internal temperature. Ambient temperature, if the thermometer is suddenly exposed to an ambient temperature difference of 20°C or higher, allow the instrument to adjust to the new ambient temperature within 20 minutes.
2) Steam, dust, smoke, etc. It blocks the optical system of the instrument and affects temperature measurement. To avoid damaging the infrared thermometer, first remove large particles and dust with compressed air, then wipe with a cloth. Gently wipe the thermometer body with a clean slightly damp cloth. If necessary, dampen the cloth with a solution of water and a little mild soap. In addition, after use, please cover the infrared thermometer with the lens cap as soon as possible, and put it in the carrying case for storage.
