Why use infrared thermal imaging camera

Development History of Infrared Thermometry Technology

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. In the past 20 years, non-contact infrared temperature measurement technology has developed rapidly, its performance has been continuously improved, its functions have been continuously enhanced, its varieties have continued to increase, its scope of application has also continued to expand, and its 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, safe use and long service life.

Infrared detection technology is a key promotion project of national scientific and technological achievements during the "Ninth Five-Year Plan". Infrared detection is an online monitoring (non-power-off) high-tech detection technology. It integrates photoelectric imaging technology, computer technology, and image processing technology. It receives objects by The emitted infrared rays (infrared radiation) display its thermal image on the fluorescent screen to accurately determine the temperature distribution on the surface of the object, which has the advantages of accuracy, real-time, and speed. Any object constantly radiates infrared heat energy due to the movement of its own molecules, thus forming a certain temperature field on the surface of the object, commonly known as "thermal image". Infrared diagnostic technology absorbs this infrared radiation energy and measures the temperature and temperature field distribution on the surface of the equipment to determine the heating condition of the equipment. At present, there are many test equipments that apply infrared diagnostic technology, such as infrared thermometers, infrared thermal imaging cameras, etc. Infrared thermal imaging equipment uses thermal imaging technology to convert this invisible "thermal image" into a visible light image, making the test effect intuitive and highly sensitive. It can detect subtle thermal state changes of the equipment and accurately reflect the internal and external conditions of the equipment. Heating conditions, high reliability, very effective in discovering hidden dangers in equipment

Infrared diagnostic technology can reliably predict early faults, defects and insulation performance of electrical equipment, improving the preventive test maintenance of traditional electrical equipment (preventive testing was a standard introduced in the former Soviet Union in the 1950s) to predictive state maintenance, which is also the standard for modern electric power equipment. The direction of enterprise development. Especially the current development of large units and ultra-high voltage has put forward increasingly higher requirements for the reliable operation of the power system, which is related to the stability of the power grid. With the continuous development and maturity of modern science and technology, the use of infrared status monitoring and diagnosis technology has the characteristics of long-distance, no contact, no sampling, no disintegration, and is accurate, fast, and intuitive to monitor and diagnose electrical equipment online in real time. Most faults (can cover the detection of various faults of almost all electrical equipment). It has attracted much attention from the power industry at home and abroad (an advanced state-of-the-art maintenance system that was widely used in foreign countries in the late 1970s) and has developed rapidly. The application of infrared detection technology is of great significance to improving the reliability and effectiveness of electrical equipment, improving operating economic benefits, and reducing maintenance costs. It is a good means currently widely promoted in the field of predictive maintenance, and it can also bring the level of maintenance and the health of the equipment to a higher level.

Infrared imaging detection technology can be used to conduct non-contact detection of running equipment, photograph the distribution of its temperature field, measure the temperature value of any part, and diagnose various external and internal faults based on this, which is real-time, telemetry, intuitive and quantitative. With advantages such as temperature measurement, it is very convenient and effective to detect operating equipment and live equipment in power plants, substations and transmission lines.

The method of using thermal imaging cameras to detect online electrical equipment is the infrared temperature recording method. Infrared temperature recording method is a new technology used in industry for non-destructive detection, testing equipment performance and understanding its operating status. Compared with traditional temperature measurement methods (such as thermocouples, wax sheets with different melting points, etc. placed on the surface or inside the body), thermal imaging cameras can detect the temperature of hot spots in real time, quantitatively, and online within a certain distance. , it can also draw the temperature gradient thermal image of the equipment during operation, and it is highly sensitive and free from electromagnetic field interference, making it easy to use on site. It can detect thermal faults in electrical equipment with a high resolution of 0.05°C in a wide range of -20°C to 2000°C, revealing such things as heating of wire joints or clamps, as well as local hot spots in electrical equipment.

Infrared diagnostic technology of live equipment is an emerging discipline. It is a comprehensive technology that utilizes the heating effect of charged equipment and uses special equipment to obtain infrared radiation information emitted from the surface of the equipment to determine the condition of the equipment and the nature of defects.

Analytical infrared thermometer thermal imaging camera

Infrared thermal imaging cameras are easy to operate and can be used together with measurement and control systems to achieve visual image generation when connected to a computer. They have been used in many fields such as product quality control and monitoring, equipment online fault diagnosis, safety protection, and energy conservation. In recent years, with the development of infrared measurement technology, infrared thermal imaging cameras that use infrared measurement principles have also developed rapidly in technology. Their specific performance performance has been continuously improved, and their scope of application has also been continuously expanded. In recent years, the market share of infrared thermal imaging cameras has increased year by year. Compared with contact temperature measurement methods, infrared thermal imaging cameras have the advantages of fast response time, non-contact, safe use and long service life.

1. Determine the temperature measurement range

Temperature measurement range is the most important performance indicator of an infrared thermal imaging camera. Each model of infrared thermal imaging camera has its own specific temperature measurement range. Therefore, the user's measured temperature range must be considered accurately and comprehensively, neither too narrow nor too wide. According to the blackbody radiation law, the change in radiant energy caused by temperature in the short-wavelength band of the spectrum will exceed the change in radiated energy caused by the emissivity error. Therefore, users only need to purchase an infrared thermal imaging camera within the temperature range they measure.

2. Determine the target size: Infrared thermal imaging cameras can be divided into single-color thermometers and double-color thermometers (radiation colorimetric thermometers) based on principles. For a monochromatic thermometer, when measuring temperature, the measured target area should fill the field of view of the thermal imager. It is recommended that the size of the measured target exceeds 50% of the field of view. If the target size is smaller than the field of view, the background radiation energy will enter the visual and acoustic signals of the infrared thermal imaging camera and interfere with the temperature measurement reading, causing errors. Conversely, if the target is larger than the camera's field of view, the camera will not be affected by the background outside the measurement area.

3. Determine the optical resolution (distance system is sensitive): The optical resolution is determined by the ratio of D and S, which is the ratio of the distance D between the infrared thermal imaging camera and the target to the measurement spot diameter S. If the thermometer must be installed far away from the target due to environmental conditions, and small targets need to be measured, an infrared thermal imaging camera with high optical resolution should be selected. The higher the optical resolution, that is, the higher the D:S ratio, the higher the cost of the infrared thermal imaging camera. Determine the wavelength range: The emissivity and surface properties of the target material determine the spectral response, or wavelength, of the thermal imaging camera. For high reflectivity alloy materials, there is low or varying emissivity. In high-temperature areas, the best wavelength for measuring metallic materials is near-infrared, and 0.18-1.0μm wavelength can be used. Other temperature zones are available with 1.6μm, 2.2μm and 3.9μm wavelengths. Since some materials are transparent at certain wavelengths, infrared energy will penetrate these materials, 2.2μm and 3.9μm (the glass to be measured must be very thick, otherwise it will pass through) wavelengths; when measuring the internal temperature of the glass, use the 5.0μm wavelength; when measuring low It is advisable to use a wavelength of 8-14μm in most cases; for another example, the wavelength of 3.43μm is used to measure polyethylene plastic film, and the wavelength of 4.3μm or 7.9μm is used for polyester. If the thickness exceeds 0.4mm, the wavelength of 8-14 μm is selected; for example, the narrow-band 4.24-4.3 μm wavelength is used to measure CO2 in the flame, the narrow-band 4.64 μm wavelength is used to measure the CO in the flame, and the 4.47 μm wavelength is used to measure the NO2 in the flame.