The main considerations when selecting an infrared thermometer are as follows:
(1) performance indicators, such as:
Temperature measurement range: each type of pyrometer has its own specific temperature measurement range, neither too narrow nor too wide, in general, the narrower the temperature measurement range, the higher the resolution of the output signal to monitor the temperature, the accuracy and reliability is easy to solve. Temperature measurement range is too wide, will reduce the accuracy of temperature measurement
Operating wavelength: According to the law of blackbody radiation, in the short wavelength band of the spectrum by the temperature-induced changes in radiant energy will exceed the change in radiant energy caused by the emissivity error, therefore, the temperature measurement should try to use the short-wave is better, but must be combined with the object to be detected to consider the emissivity of the factors:
The emissivity of the target material and surface properties determine the corresponding wavelength of the spectra of the pyrometer, for high reflectivity alloy materials, there are low or changing emissivity. In the high temperature zone, the measurement of metal materials jia wavelength is near infrared, can choose 0.8 ~ 1.0 μm. other temperature zones can be selected 1.6, 2.2 and 3.9 μm. due to some materials at a certain wavelength is transparent, infrared energy will penetrate these materials, for this material should choose a special wavelength, such as measuring the internal temperature of the glass wavelengths 1.0, 2.2 and 3.9 μm (the glass to be tested) To be very thick, otherwise it will pass through); measure the surface temperature of the glass selection of 5.0 μm; measurement of low-temperature zone selection of 8 ~ 14 μm is appropriate, as well as the measurement of polyethylene plastic film selection of 3.43 μm, polyester class selection of 4.3 or 7.9 μm, the thickness of more than 0.4mm selection of 8 ~ 14 μm, such as measurement of the flame CO with a narrow band of 4.64 μm, measurement of the flame of 4.47 μm with the NO2, and so on.
Spot size: pyrometer measuring point of the area called "spot size" (spot size), in order to obtain the temperature readings, pyrometer and test the distance between the target must have a suitable range, the farther away from the target, the larger the spot size. Therefore, in the application should pay attention to the distance and spot size ratio, or D: S. In determining the measurement distance, attention should be paid to make the target diameter is equal to or greater than the measured spot size. If the target is smaller than the spot size being measured, the pyrometer will be measuring the temperature of the background object at the same time, thus reducing the readability of the reading.
(2) environmental and working conditions
Protection of accessories: the environmental conditions in which the pyrometer has a great impact on the measurement results, such as not properly resolved, will affect the temperature measurement accuracy or even cause damage. When the ambient temperature is high, the presence of dust, smoke and steam conditions, you can choose to use the manufacturer to provide a protective cover, water cooling, air cooling system, air blowers and other accessories. These accessories can effectively solve the environmental impact and protect the pyrometer to achieve accurate temperature measurement. When in the noise, electromagnetic fields, vibration or difficult to access the environmental conditions, or other harsh conditions, smoke, dust or other particles to reduce the measurement of energy signal, more appropriate is to choose the fiber optic dual-color pyrometer.
(3) other options, such as simple operation, ease of use, maintenance and calibration performance and price.
For example, portable infrared thermometer, which is a set of temperature measurement and display output as one of the small, lightweight, carried by people for temperature measurement instruments, in the display panel can display the temperature and output a variety of temperature information, and some can also be operated by remote control or through a computer software program.
Translated with DeepL.com (free version)
