Self-calibration method of thermometer
The most important factors for infrared thermometers to ensure temperature measurement accuracy are emissivity, distance to the spot, position of the spot, and field of view. During the self-calibration, the comparison of the basic error, the influence of the measurement distance change, and the determination of the range of the emissivity are completed. Before the test, 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 principle of the blackbody furnace and practical work experience, the comparison standard used in the self-calibration is a self-made simple blackbody water tank. The size of the water tank is 450mmx300mm, made of self-iron sheet, and an electric heater is installed inside. Use a 1.5-grade pressure thermometer with good stability (can be replaced by a certified glass liquid thermometer) as a standard device 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 tested to compensate, so that 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 real temperature. At the same time, considering the spot positioning test, paste 80mmx80mm black tape on the liquid surface at the same depth as the pressure thermometer probe. After the water in the water tank boils for 5 minutes, when the temperature field in the water tank is uniform, use an infrared tester to aim at the center of the black tape. Comparison
Technical requirements for infrared thermometers:
The basic error of the infrared thermometer and the impact of the measurement distance change do not exceed the provisions in Table 1.
Calibration items for infrared thermometers:
According to the field use and practical experience, the calibration project mainly completes the visual inspection, the determination of the basic error, the determination of the influence of the change of the measurement distance and the determination of the emissivity range.
Calibration steps for infrared thermometers:
1) Appearance inspection, all parts are assembled in good condition and there is no defect;
2) Characters, signs and scales should be complete and clear;
3) The appearance and parts should be well treated, without 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 surface of the lens should be cleaned, and the floating dust on the surface should be blown off with clean air, or the dust should be brushed off with a soft brush.
