Analysis of infrared thermometer
- 2018-12-24-

Infrared thermometer is an indispensable tool for detecting the internal structure of power transformers. Infrared thermometer technology has been developed to scan and measure the surface with thermal changes, determine its temperature distribution image, and quickly detect hidden temperature differences. When measuring the temperature of an object with an infrared radiation thermometer, first measure the amount of infrared radiation in the target's band, and then calculate the temperature of the measured object with the thermometer. Monochromatic thermometers are proportional to the amount of radiation in the band; dual-color thermometers are proportional to the ratio of the amount of radiation in the two bands.

Infrared thermometer classification

Infrared thermometers can be divided into monochrome thermometers and dual-color thermometers according to the principle. For a monochrome thermometer, when measuring temperature, the area of the target to be measured should be filled with the field of view of the thermometer. If the size of the target is smaller than the field of view, the background radiant energy will enter the thermophone's visual note branch and interfere with the temperature reading Cause errors. For a two-color thermometer, its temperature is determined by the ratio of the radiant energy in two independent wavelength bands. For a small target that is in motion or vibration, it sometimes moves in the field of view, or it may be partially removed. The target of the field of view, under these conditions, using a two-color thermometer is a good choice.

Principle of infrared thermometer

The infrared thermometer consists of optical system, photodetector, signal amplifier, signal processing, display output and other parts. The radiation of the measured object and the feedback source is modulated by the modulator and input to the infrared detector. The difference between the two signals is amplified by an inverting amplifier and controls the temperature of the feedback source, so that the spectral radiance of the feedback source is the same as the spectral radiance of the object, and the display indicates the brightness temperature of the measured object.

In order to measure the temperature, point the instrument at the object to be measured, and read the temperature data on the LCD of the instrument according to the trigger to ensure that the ratio between the distance and the spot size and the field of view are arranged. Editors remind:

Matters needing attention when using infrared thermometer:

1. Only the surface temperature is measured. The infrared thermometer cannot measure the internal temperature.

2. The temperature cannot be measured through quartz glass with a wavelength above 5um. The glass has very special reflection and transmission characteristics, which does not allow accurate infrared temperature readings. However, the temperature can be measured through an infrared window. Infrared thermometers are not used for measuring the temperature of shiny or polished metal surfaces (stainless steel, aluminum, etc.).

3. Locate the hot spot. To find the hot spot, the instrument aims at the target, and then scans up and down on the target until the hot spot is determined.

4. Pay attention to environmental conditions: steam, dust, smoke, etc. It blocks the optical system of the instrument and affects accurate temperature measurement.

5. 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.

Through the introduction of the above content, I believe that everyone already knows it. If you want to know more about the infrared thermometer, you can continue to follow us.