Infrared thermometer is the use of infrared wavelengths between 0.76 ~ 100μm, scanning and imaging of objects, to carry out the object of the equipment online troubleshooting and safety protection and energy saving, etc., so the infrared thermometer has always been an important national research projects, including in daily life, and even in the field of medical science, are acting as an important role for the We detect the existence of many but invisible problems, but what is his working principle? I'll explain it to you.
Theoretical principle of infrared thermometry
In nature, when the temperature of the object is higher than absolute zero, due to the existence of its internal thermal movement, it will continue to radiate electromagnetic waves to the surrounding area, which contains infrared wavelengths located in the band of 0.75 μm ~ 100 μm. His most important feature is that at a given temperature and wavelength, the object emits a maximum value of radiant energy, this material is called a blackbody, and set his reflection coefficient of 1, the other material reflection coefficient is less than 1, called the gray body, due to the spectral radiant power of the blackbody P (λT) and the absolute temperature T to meet the Planck's fixed between. It means that at the absolute temperature T, the radiant power of the blackbody per unit area at wavelength λ is P(λT). According to this relationship can get the corresponding relationship curve, can be out:
(1) as the temperature rises, the object's radiant energy is stronger. This is the starting point of the theory of infrared radiation, but also single-band infrared thermometer design basis.
(2) As the temperature rises, the radiation peak moves in the direction of the short-wave (to the left), and satisfies the Venn displacement theorem ? that the wavelength at the peak ? is inversely proportional to the absolute temperature T. The dashed line is the ? at the peak of the line. This formula tells us why high-temperature pyrometer more work in the short-wave, low-temperature pyrometer more work in the long-wave.
(3) the rate of change of radiant energy with temperature, short-wave than the long-wave temperature, that is, the short-wave thermometer work at the relative signal-to-noise ratio is high (high sensitivity), anti-interference, the thermometer should try to choose to work at peak wavelengths, especially low-temperature small targets, this is particularly important.
Principle of infrared thermometer
Infrared thermometer consists of optical systems, photodetectors, signal amplifiers and signal processing, display output and other components. The radiation lines of the measured object and the feedback source are modulated by the modulator and input to the infrared detector. The difference between the two signals is amplified by the inverse amplifier and controls the temperature of the feedback source, so that the spectral radiation brightness of the feedback source is the same as the spectral radiation brightness of the object. The display indicates the brightness temperature of the object under test.
This is a small summary of the principle of infrared thermometer, do you know clearly? It is the measurement of temperature above absolute zero of the object, are due to their own molecular movement and radiated infrared radiation. It is in the inspection, maintenance and calibration of the temperature can greatly improve the efficiency of work, save time, improve the availability of equipment and systems. Infrared thermometer has now been used in electric power, metallurgy, petrochemical and other aspects, and even air transportation is also the field of infrared thermometer.
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