The impact and countermeasures of atmospheric attenuation on infrared thermometers for non-destructive testing

Since the infrared radiation energy on the surface of the inspected electrical equipment is transmitted to the infrared detection instrument through the atmosphere, it will be attenuated by the absorption and attenuation of gas molecules such as water vapor, carbon dioxide, carbon monoxide in the atmospheric combination and the scattering of suspended particles in the air. The attenuation of the equipment radiation energy transmission decreases with the distance between the detection instrument and the equipment under test, reducing the radiation transmittance of the equipment under test. Therefore, its attenuation increases with the increase of distance, reducing the radiation contrast between the faulty part and the normal part of the equipment under test. The target energy received by the infrared instrument is reduced, making the temperature displayed by the instrument lower than the actual temperature value of the fault point under test, resulting in missed detection or misdiagnosis. This is especially unfavorable for detecting equipment failures with low temperature rise. As the detection distance increases, the influence of the atmospheric combination will become greater and greater. In addition, in order to obtain the accuracy of the target temperature, the following countermeasures must be taken: try to choose a season when the ambient atmosphere is relatively dry and clean for detection; shorten the detection distance as much as possible without affecting safety, and make reasonable distance corrections to the temperature measurement results in order to measure the actual temperature value.

Impact of meteorological conditions

Bad weather conditions (rain, snow, fog, strong wind, etc.) will have an adverse effect on the temperature detection of the equipment, often giving false fault phenomena. In order to reduce the impact of weather conditions, try to perform the test at night when there is no rain, fog, wind, and the ambient temperature is relatively stable.