What is the normal temperature of infrared thermometer?
Theoretical principle of infrared temperature measurement
In nature, when the temperature of an object is above absolute zero, due to its internal thermal motion, it will continuously radiate electromagnetic waves in all directions, including infrared radiation with a wavelength range of 0.75 μ m to 100 μ m. His biggest characteristic is that at a given temperature and wavelength, an object emits radiation with a maximum value. This substance is called a blackbody, and its reflection coefficient is set to 1. Other substances with a reflection coefficient less than 1 are called gray bodies, because the spectral radiation power P (λ T) of a blackbody satisfies Planck's law with respect to the absolute temperature T. At absolute temperature T, the radiation power of a blackbody per unit area at wavelength λ is P (λ T). Based on this relationship, the corresponding relationship curve can be obtained, which leads to:
(1) As the temperature increases, the radiation energy of an object becomes stronger. This is the starting point of infrared radiation theory and the design basis of single band infrared thermometers.
(2) As the temperature increases, the radiation peak shifts towards the short wave direction (to the left) and satisfies the Wien shift theorem. The wavelength at the peak is inversely proportional to the absolute temperature T, and the dashed line is the line connecting the peak. This formula tells us why high-temperature thermometers work more at short wavelengths and low-temperature thermometers work more at long wavelengths.
(3) The rate of change of radiation energy with temperature is greater at short wavelengths than at long wavelengths, indicating that thermometers operating at short wavelengths have a higher relative signal-to-noise ratio (sensitivity) and stronger anti-interference ability. Therefore, thermometers should be selected to operate at peak wavelengths as much as possible, especially for low-temperature small targets. This is particularly important.
What is the normal temperature for an infrared thermometer
1. When using an infrared thermometer to measure the surface temperature of luminous objects, such as aluminum and stainless steel, the surface reflection will affect the reading of the infrared thermometer.
2. Before reading the temperature, a rubber strip can be placed on the metal surface, and after the temperature is balanced, the temperature in the rubber strip area can be measured.
3. Using an infrared thermometer to move back and forth from the kitchen to the refrigeration area can still provide accurate temperature measurement, but it needs to be measured after a period of time in a new environment to reach temperature equilibrium.
4. It is best to place the thermometer in a frequently used location.
