The infrared thermometer has to be selected correctly.
Infrared temperature measurement technology plays an important role in my country's product quality control and monitoring, equipment online fault diagnosis, protection and energy conservation. In the past two decades, non-contact infrared thermometers have developed rapidly in technology, their performance has been continuously improved, their scope of application has been continuously expanded, and their market share has increased year by year. Compared with contact temperature measurement methods, infrared temperature measurement has the advantages of fast response time, non-contact, long use and service life. Digital noise meters also play a role in measuring sound levels.
Working principle of external line thermometer:
Understanding the working principle, technical indicators, environmental working conditions, operation and maintenance of external thermometers is to help users correctly select and use infrared thermometers.
All objects with a temperature above zero are constantly emitting infrared radiation energy into the surrounding space. The infrared radiation characteristics of an object-the size of the radiation energy and its distribution by wavelength-are closely related to its surface temperature. Therefore, by measuring the infrared energy radiated by the object itself, its surface temperature can be accurately measured. This is the objective basis on which infrared radiation temperature measurement is based.
Thermometer black body radiation law:
A black body is an ideal radiator that absorbs radiant energy of all wavelengths without energy reflection or transmission, and its surface emissivity is 1. It should be pointed out that there is no real black body in nature, but in order to clarify and obtain the distribution rules of infrared radiation, an appropriate model must be selected in theoretical research. This is the quantized oscillator model of body cavity radiation proposed by Jintai Keyi, thus deriving The law of black body radiation of Jintai Keyi, that is, the black body spectral radiance expressed in wavelength, is the starting point of all infrared radiation theories, so it is called the black body radiation law.
The influence of thermometer object emissivity on radiation temperature measurement:
Almost all actual objects that exist in nature are not black bodies. The radiation amount of all actual objects depends not only on the radiation wavelength and the temperature of the object, but also on factors such as the type of material, preparation method, thermal process, surface state and environmental conditions of the object. Therefore, in order to make the black body radiation law applicable to all real objects, a proportional coefficient related to the material properties and surface state must be introduced, that is, the emissivity. This coefficient represents how close the thermal radiation of an actual object is to blackbody radiation, and its value is between zero and a value less than 1. According to the radiation law, as long as you know the emissivity of the material, you can know the infrared radiation characteristics of any object.
The main factors that affect the emissivity of infrared thermometers are:
Material type, surface roughness, physical and chemical structure and material thickness, etc.
When using an infrared radiation thermometer to measure the temperature of a target, the amount of infrared radiation of the target within its band range must first be measured, and then the temperature of the measured target is calculated by the thermometer. A single-color thermometer is proportional to the amount of radiation within the band: a two-color thermometer is proportional to the ratio of the amount of radiation in the two bands.
The infrared thermometer must correctly select the infrared system:
Infrared thermometer consists of optical system, photoelectric detector, signal amplifier, signal processing, display output and other parts. The optical system gathers the target infrared radiation energy within its field of view, and the size of the field of view is determined by the optical parts of the thermometer and its position. The infrared energy is focused on the photodetector and converted into a corresponding electrical signal. The signal passes through the amplifier and signal processing circuit, and is converted into the temperature value of the measured target after correction according to the internal treatment algorithm of the instrument and the target emissivity.
