Principles of Infrared Thermometers _ Calibration of Infrared Thermometers
Infrared temperature measurement technology plays an important role in product quality control and monitoring, equipment online fault diagnosis and safety protection, and energy conservation during the production process. Compared to contact temperature measurement methods, infrared temperature measurement has advantages such as fast response time, non-contact, safe use, and long service life. So, what is the principle of an infrared thermometer? What should be noted when using?
The principle of an infrared thermometer is as follows:
1. Infrared principle
Any object with a temperature higher than absolute zero (-273 ℃) emits thermal radiation to the outside. The energy emitted by an object varies depending on its temperature, and the wavelength of the radiation wave also varies. However, it always includes infrared radiation. Objects below a thousand degrees Celsius have strong electromagnetic waves in their thermal radiation, which are infrared waves. Therefore, measuring the infrared radiation of the object itself can accurately determine its surface temperature. This is the objective basis for infrared thermometer temperature measurement.
2. Working principle
The non-contact infrared thermometer consists of an optical system, a photodetector, a signal amplifier, signal processing, display output, and other components. The optical system gathers the infrared energy emitted by the target object, focuses it on the photodetector, and converts it into the corresponding electrical signal. After being processed by the circuit, it is converted into a linear temperature signal value of the measured target, in order to achieve further signal processing and control.
Calibration steps of infrared thermometer
In the production process, infrared temperature measurement technology plays an important role in product quality control and monitoring, equipment online fault diagnosis, safety protection, energy conservation, and other aspects. In the past 20 years, non-contact infrared thermometers have developed rapidly, with improved performance, continuously enhanced functions, an increasing variety, and an expanding range of applications. Compared with contact temperature measurement methods, infrared temperature measurement has advantages such as fast response time, non-contact, safe use, and long service life. The non-contact infrared thermometer consists of three series of portable, online scanning, multiple options, and computer software, each with multiple models and specifications. It is very important for users to choose the correct infrared thermometer among various specifications of thermometers.
The calibration steps for an infrared thermometer are as follows:
According to the temperature measurement range, place a metal material sample with a diameter larger than the required infrared thermometer diameter in the resistance furnace. Test the above-mentioned standard S-type precious metal thermocouple, using the thermocouple as the reference temperature source. To ensure the relative stability of the temperature source, the expansion uncertainty of the reference calibration temperature source should not exceed the table.
Calibration method: Calibrate the environmental conditions, environmental temperature (18-25) C reference standard, and the humidity of the working environment of the electrical measurement device should be consistent with it.
Technical requirements are required.
Relative humidity:>85%, avoid strong background radiation and alternating magnetic fields.
Supporting facilities: The accuracy of the standard temperature source (converted to temperature) for S-type thermocouples and their measuring point equipment should be better than 1/10 of the maximum allowable error of the infrared measuring instrument.
The insulation resistance meter with a rated voltage of 520V has been calibrated.
The digital display must be clear and complete, and the buttons must be normal. When the battery is low, it can be calibrated after replacing the battery.
Calibration result processing: The calibration data processing is based on the implementation of the full radiation thermometer verification regulations. The calibration process is recorded on the infrared thermometer calibration record form, and the calibration report is filled out after the calibration is completed.
