With the development of infrared thermometer technology, it has the advantages of convenient use, high measurement accuracy and long measurement distance, providing users with instruments with various functions and uses.
In principle, there are two types of infrared thermometers: portable thermometers and stationary thermometers. Therefore, when choosing an infrared thermometer suitable for different measuring points;
The following characteristics will be the main ones:
1. View
The viewfinder has this function, the measuring block or measuring point pointed by the thermometer can be seen, and the measuring object with a large area often does not need of a collimator.
For small measured objects and long measuring distances, it is recommended to use the collimator with a dashboard scale or a laser pointing point under the fform of a light-transmitting lens.
2. Lens
The lens determines the measured point of the thermometer. For large area objects, it usually has a fixed focal length. A thermometer is sufficient.
But when the measuring distance is far away from the focus point, the image at the edge of the measuring point will be blurred.
For this reason, it is better to use a zoom. Within the given zoom range, the thermometer can adjust the measurement distance;
New measurement The pyrometer has a replaceable zoom lens, and the near lens and the far lens can be replaced without rechecking the calibration.
3. The sensor, that is to say the spectral receiver
The temperature is inversely proportional to the wavelength.
At low object temperatures, sensors sensitive to the long-wave spectral region (hot-film sensors or pyroelectric sensors) are suitable, and at elevated temperatures short-wave sensitive sensors will be used. Photosensors made of germanium, silicon, indium-gallium, etc.
When selecting spectral sensitivity, the absorption bands of hydrogen and carbon dioxide should also be considered.
In a certain range of wavelengths, called the \"atmospheric window\", H2 and CO2 are almost transparent to infrared rays;
Sensitivity in the light of the thermometer should be within this range in order to exclude the influence of changes in atmospheric concentration. When measuring thin films or glasses, it should also be considered that these materials are not easy to penetrate in a certain wavelength.
To avoid measurement errors caused by background light, use an appropriate sensor that only receives the surface temperature;
The metals havethis physical property, the emissivity When the wavelength decreases, it increases. As a general rule, when measuring the temperature of metals, a short measurement wavelength is usually selected.
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