Method for the self-calibration of an infrared thermometer
The most important factors for an infrared thermometer to ensure temperature measurement accuracy are the emissivity, the distance to the light spot, the position of the light spot, and the field of view. During self-calibration, the comparison of basic errors, the impact of changes in measurement distance, and the determination of the range of emissivity are completed. Before testing, the infrared thermometer is adjusted to the best state and then used for on-site testing.
The self-calibration method of the infrared thermometer is as follows:
Referring to the principles and practical work experience of blackbody furnaces, the comparison standard used in self-calibration is a self-made simple blackbody water tank with a size of 450mmx300mm, made from iron sheet, and equipped with an electric heater inside. Use a 1.5-level pressure thermometer with good stability (a certified glass liquid thermometer can be used instead) as a standard instrument to test the temperature in the water tank. Considering that it is necessary to measure the surface temperature of most organic materials, paints or oxidized surfaces, Apply black tape or flat black paint to the surface to be measured to compensate. When the black tape or black paint reaches the same temperature as the base material, measure the temperature of the tape or paint surface, which is the working experience of the true temperature. At the same time, consider the spot positioning test. Use an 80mmx80mm black tape and stick it on the liquid surface at the same depth as the pressure thermometer probe. After the water in the water tank boils for 5 minutes and the temperature field in the water tank is uniform, use the infrared tester to aim at the center point of the black tape. Comparison
Technical requirements for infrared thermometer:
The basic error of the infrared thermometer and the impact of changes in measurement distance do not exceed the requirements in Table 1.
Calibration items for infrared thermometer:
Based on on-site usage and practical experience, the calibration project mainly completes appearance inspection, determination of basic errors, determination of the impact of changes in measurement distance, and determination of the range of emissivity.
Calibration steps for infrared thermometer:
1) Appearance inspection, all parts are assembled intact and without defects;
2) Characters, marks, and scales should be complete and clear;
3) The appearance and parts should be well treated and free of rust and mildew;
4) If the "BAT" prompt appears, replace the battery in time;
5) The objective lens and eyepiece are not damaged, and the aiming should be clear. If the environment is dusty, the lens surface should be cleaned, blow off the dust on the surface with clean air, or brush off the dust with a soft brush.
