Definition
An industrial thermometer is a non-contact infrared thermometry instrument that measures the temperature of an object by receiving infrared energy radiated from its surface. It is widely used in industrial production, equipment maintenance, quality control, and other fields, suitable for measuring moving objects, high temperatures, or hard-to-reach targets, providing a convenient and efficient solution for on-site temperature monitoring.
Principle
Industrial thermometer guns work based on the law of blackbody radiation. Any object above absolute zero will radiate infrared energy outward, and its radiation intensity corresponds to the surface temperature of the object. The optical system of the thermometer gun collects the infrared radiation emitted by the target and focuses it on the infrared detector. The detector converts the radiated signal into an electrical signal, which is processed and calibrated by temperature before finally being displayed as a temperature reading. The process follows Stefan-Boltzmann's law, the basic relationship of which can be expressed as:
M = εσT4
where M is the radiated emissivity, ε is the surface emissivity, σ is the Stefan-Boltzmann constant, and T is the absolute temperature.
Measurement method
When using industrial temperature measuring guns, it is necessary to ensure that the measurement optical path is clear and there is no interference from smoke, steam and other media. The operator should keep the temperature gun perpendicular to the surface to be measured and measure within the specified distance factor. For different materials, the corresponding emissivity parameters need to be set in advance. It is recommended to take the average value multiple times during the measurement process, and pay attention to the effect of ambient temperature on the instrument itself. For high-temperature or moving targets, stable data can be obtained using peak hold or continuous monitoring mode.
Influencing factors
Measurement accuracy is influenced by various factors. The surface emissivity of objects is the main influencing factor, and the surface emissivity of different materials varies significantly. The measurement distance must meet the distance coefficient requirements of the instrument calibration, and errors may be introduced if it is too far or too close. Water vapor and dust in the environment will absorb infrared radiation, and strong ambient light sources may cause interference. The measured surface condition such as oxidation degree and roughness will also affect the radiation characteristics. The thermal stability of the instrument itself is just as important as regular calibration.
Applications
It is used in the power system to detect the hidden heat hazard of transformer and circuit breaker contacts. Monitoring of molten metal temperature, roll surface temperature in the metallurgical industry. It is used in the manufacturing industry for injection molding and glass molding process control. In the construction field, the thermal insulation performance of the wall and the distribution of the floor heating system can be detected. Food processing monitors baking and sterilization temperatures. In addition, it has mature applications in scientific research experiments, equipment preventive maintenance, energy audits, etc.
Selection reference
The measurement range should be comprehensively considered when selecting, and the temperature extremes in the actual application should be covered and appropriate margins should be retained. Optical resolution is determined by the distance factor, and higher resolution is required to measure small targets at long distances. The response time should be selected according to the rate of temperature change being measured. The adjustable range of emissivity needs to be adapted to common materials. The environmental protection level should match the dust and humidity conditions of the usage scenario. Data output functions such as analog output and digital interface can be configured according to system integration needs. At the same time, it is necessary to pay attention to the international standards such as the IEC/EN 61010 series of safety standards.