What is a Thermal Lance?

Infrared temperature measurement technology plays an important role in the production process in product quality control and monitoring, equipment online fault diagnosis and safety protection, and energy conservation. In the past 20 years, non-contact infrared human body thermometers have developed rapidly in technology, with constant improvements in performance, continuous enhancement of functions, increasing varieties, and expanding scope of application. Compared with contact temperature measurement method, infrared temperature measurement has the advantages of fast response time, non-contact, safe use and long service life. The non-contact infrared thermometer includes three series: portable, online and scanning, with various options and computer software. Each series has various models and specifications. Among the various types of thermometers with different specifications, the correct choice of the infrared thermometer model is very important for the user.

In 1672, people discovered the sunlight (

In 1800, the British physicist FW Husser discovered

Infrared camera is using

Infrared thermal imaging cameras are generally spectroscopic scanning imaging systems and non-scanning imaging systems. Opto-mechanical scanning imaging system uses unit or multi-element (8, 10, 16, 23, 48, 55, 60, 120, 180 or more) photoconductive or photovoltaic infrared detectors. The speed is slow when using unit detectors. Mainly because the frame response time is not fast enough, the multi-element array detector can be made into a high-speed real-time thermal imager. Non-scanning thermal imaging cameras, such as the focal plane thermal imaging cameras for array gaze imaging introduced in recent years, are a new generation of thermal imaging devices, which are significantly better than optical-machine scanning thermal imaging cameras, and have gradually replaced them. Opto-Mechanical Scanning Camera Trends. The key technology is that the detector consists of

1. Working band; working band refers to the response of the infrared detector selected in the infrared camera

1.Types of infrared temperature measuring instruments

There are three main types of infrared temperature measuring instruments: infrared cameras, infrared televisions, and infrared thermometers (point thermometers). In the 1960s, China successfully developed the first infrared thermometer, and since the early 1980s, it has successively produced small target, long-distance, temperature measuring instruments suitable for the production characteristics of the electrical industry, such as Xiguang IRT-1200D, HCW-, HCW -V type; YHCW-9400 type; WHD4015 type (dual sight, target D 40mm, up to 15 m), WFHX330 type (optical sight, target D 50 mm, up to 30 m). PM-20, 30, 40, 50, and HAS-201 thermometers produced in the United States; TGA 20, 30, 40, 50, etc. from Sweden's AGA also have a wide range of applications. DL-500 E can be applied to 110 ~ 500 kV transformer equipment, with clear images and accurate temperature. Infrared thermal imagers include Japan TVS-2000, TVS-100, US PM-250, Sweden AGA-THV510, 550, 570. The domestic infrared camera was successfully developed in Kunming and localized.

2.Infrared thermometer working principle

Understanding the working principle, technical indicators, environmental working conditions, and operation and maintenance of infrared thermometers is the basis for users to properly select and use infrared thermometers. The optical system collects the target infrared radiation energy in its field of view, and the size of the field of view is determined by the optical parts and position of the thermometer. The infrared energy is focused on the photodetector and converted into a corresponding electrical signal. This signal is converted into the temperature value of the measured target after being corrected by the amplifier and the signal processing circuit according to the algorithm and target emissivity of the instrument. In addition, the environmental conditions in which the target and the thermometer are located, such as temperature, atmosphere, pollution, and interference, should be considered for the impact on performance indicators and correction methods.

All objects whose temperature is above absolute zero are constantly emitting infrared radiation energy to the surrounding space. The amount of infrared radiation energy of an object and its distribution by wavelength are very closely related to its surface temperature. Therefore, by measuring the infrared energy radiated by the object itself, it can accurately determine its surface temperature, which is the objective basis on which infrared radiation temperature measurement is based.

In order to obtain accurate temperature readings, the distance between the thermometer and the test target must be within a suitable range. The so-called "spot size" is the area of the thermometer's measurement points. The farther you are from the target, the larger the spot size. The figure on the right shows the ratio of distance to spot size, or D: S. On a laser sight type thermometer, the laser spot is above the center of the target with a 12mm (0.47 inch) offset distance.

When setting the measurement distance, make sure that the target diameter is equal to or larger than the measured spot size. The distance between object 1 marked on the right and the measuring instrument is positive, because the target is slightly larger than the measured spot size. The "object No. 2" is too far away because the target is smaller than the measured spot size, that is, the thermometer is measuring the background object at the same time, thereby reducing the accuracy of the reading. ^[2]

The choice of infrared thermometer can be divided into 3 aspects:

(1) In terms of performance indicators, such as temperature range, spot size, working wavelength, measurement accuracy, window, display and output, response time, protection accessories, etc .;

(2) Environmental and working conditions, such as ambient temperature, window, display and output, protection accessories, etc .;

(3) Other options, such as ease of use, maintenance and calibration performance, and price, also have a certain impact on the choice of thermometer.

With technology and continuous development,

1. Determine the temperature measurement range

Determine the temperature measurement range: The temperature measurement range is one of the most important performance indicators of the thermometer. Some thermometers range from -50 ° C to + 3000 ° C, but this cannot be done with one type of infrared thermometer. Each type of thermometer has its own specific temperature range. Therefore, the user's measured temperature range must be considered accurate and comprehensive, neither too narrow nor too wide. According to the law of black body radiation, the change in radiant energy caused by temperature in the short wavelength band of the spectrum will exceed the change in radiant energy caused by emissivity errors. Therefore, it is better to use short waves when measuring temperature. Generally speaking, the narrower the temperature measurement range, the higher the resolution of the output temperature monitoring signal, and the easier the accuracy and reliability can be solved. The temperature measurement range is too wide, which will reduce the temperature measurement accuracy. For example, if the measured target temperature is 1000 ° C, first determine whether it is online or portable, and if it is portable. There are many models that meet this temperature, such as 3iLR3, 3i2M, 3i1M. If the measurement accuracy is main, it is better to choose 2M or 1M model, because if you choose 3iLR type, its temperature measurement range is wide, the high temperature measurement performance will be worse; if the user in addition to measuring the target of 1000 , also take care Low temperature target, that had to choose 3iLR3.

.2 Determine the target size

Infrared thermometers can be divided into monochrome thermometers and dual-color thermometers (radiochromatic thermometers) according to the principle. For a monochrome thermometer, when measuring temperature, the area of the target to be measured should be filled with the field of view of the thermometer. It is recommended that the size of the target to be measured exceeds 50% of the field of view. If the size of the target is smaller than the field of view, the background radiant energy will enter the audiovisual notes of the thermometer and interfere with the temperature reading, causing errors. Conversely, if the target is larger than the field of view of the thermometer, the thermometer will not be affected by the background outside the measurement area. For a colorimeter, the field of view is not full, and there are smoke, dust, and obstructions on the measurement path, and when the radiation energy is attenuated, it will not have a significant impact on the measurement result. For small targets that are in motion or vibration, a colorimeter is the best choice. This is due to the small diameter and flexibility of the light, which can transmit light radiation energy on curved, blocked and folded channels.

For some thermometers, the temperature is determined by the ratio of the radiant energy in two independent wavelength bands. Therefore, when the target to be measured is small and not full, and there is smoke, dust, or obstruction on the measurement path that attenuates the radiant energy, it will not affect the measurement result. Even in the case of energy attenuation of 95%, the required temperature measurement accuracy can still be guaranteed. For targets that are small and moving or vibrating; sometimes moving in the field of view, or targets that may partially move out of the field of view, under these conditions, using a two-color thermometer is the best choice. If direct aiming between the thermometer and the target is impossible, and the measurement channel is curved, narrow, blocked, etc., a two-color fiber optic thermometer is the best choice. This is due to its small diameter and flexibility, which can transmit light radiation energy on curved, blocked and folded channels, so it can measure targets that are difficult to access, harsh conditions or close to electromagnetic fields.

.3 Determine the distance coefficient (optical resolution)

The distance coefficient is determined by the ratio of D: S, which is the ratio of the distance D from the thermometer probe to the target to the diameter of the target to be measured. If the thermometer must be installed away from the target due to environmental conditions, and you need to measure a small target, you should choose a thermometer with high optical resolution. The higher the optical resolution, that is, increasing the D: S ratio, the higher the cost of the thermometer. Raytek infrared thermometers D: S range from 2: 1 (low distance coefficient) to above 300: 1 (high distance coefficient). If the thermometer is far away from the target and the target is small, you should choose a thermometer with a high distance coefficient. For a fixed focal length thermometer, the minimum position of the light spot is at the focal point of the optical system, and the light spot near and far from the focal point will increase. There are two distance coefficients. Therefore, in order to accurately measure temperature at distances close to and away from the focus, the size of the measured target should be larger than the spot size at the focus. The zoom thermometer has a minimum focus position, which can be adjusted according to the distance to the target. Increasing D: S will reduce the received energy. If the receiving aperture is not increased, the distance coefficient D: S will be difficult to increase, which will increase the cost of the instrument.

4.Determine the wavelength range

The emissivity and surface characteristics of the target material determine the

Ultra-compact temperature calibrator, which overcomes the technical difficulties caused by miniaturization to the greatest extent, and enables users to carry it to every corner of the industrial site, and carry out on-site calibration of temperature probes that need to be checked, repaired and calibrated. , Eliminates the trouble of disassembling it back to the laboratory for comparative calibration, and reinstalling the original system, which can greatly improve work efficiency, save time, increase the availability of equipment and systems, and provide excellent on-site automatic control engineers. Maintenance and calibration methods.

AIKOM series ultra-compact temperature calibrator has changed the traditional temperature calibration mode. It has a wide range of applications, covering every aspect of temperature measurement and calibration in the industrial field, and provides an adjustable analog temperature source to improve the process flow. The level of control, product quality assurance, and prevention of misoperations and fault finding of automatic protection settings in industrial processes provide important means of inspection. Especially for the constant value check of the temperature switch, it can be done quickly, accurately and conveniently, and its application fields involve:

Electricity: coal-fired power plants, gas-fired heating power plants, hydropower stations, nuclear power stations, district heating pipeline networks, temperature protection and signal transmission of large power transformers, etc.

Metallurgy: aluminum plant, copper plant, steel plant, etc.

Petrochemical: oil production, pipelines, petrochemical plants, refineries.

General industry: refrigerator factory, air conditioner factory, refrigerator factory, beer factory, pharmaceutical factory, automobile factory.

Manufacturers of temperature components: Manufacturers of platinum resistors, thermocouples and compensating wires and cables, temperature switches, and temperature sensors.

Transportation: Aircraft maintenance at airports, large-scale transportation power system maintenance, and ocean shipping are used as in-service maintenance measurement methods.

Aikom products are mainly launched in the Chinese market with two models (PD-1000 / PD-2000) and four models. PD-1025 is characterized by the use of

Temperature, pressure, current, voltage, etc. are all basic physical quantities with which people are familiar. In the industrial field, it has a great impact on product quality and full process control. Among these basic physical quantities, the measurement and calibration of temperature is much more difficult. This is because the influence of the "adiabatic" and "heat transfer" of the temperature system itself is very complicated, which results in a large volume of temperature measurement calibration system, long stabilization time, and difficulty in improving accuracy. It is not like the pressure system, as long as the pressure transmission pipeline is leaked, the internal and external pressures can be ensured without affecting each other. In this way, it is easy to realize the rapid transmission of pressure, the stabilization time is only a few milliseconds, and the measurement accuracy can easily reach more than ten thousandths.

Let's take a look at a high-precision and high-stability temperature measurement system to ensure that it is "adiabatic", that is, it is impossible to completely prevent heat transmission. People usually make a sufficiently large volume to reach a thermal equilibrium, and consider that the temperature field gradient of a small volume at the center of its internal mass is sufficiently balanced, which is one of the important reasons why the temperature calibration source is bulky. In addition, the heat transfer of a temperature system is also very complicated, which is often completed by heat conduction, convection and radiation. It is conceivable that it is almost impossible to suddenly change the temperature and reach thermal equilibrium. This is the source of conventional temperature calibration. To ensure a certain temperature field uniformity, the device is large, and the rise and fall time is long, resulting in the inspection, maintenance and calibration of the temperature measurement system in the industrial field, which is time-consuming, labor-intensive, and affected by repeated disassembly of the temperature probe

In order to measure the temperature, point the instrument at the object to be measured, and read the temperature data on the LCD of the instrument according to the trigger to ensure that the ratio between the distance and the spot size and the field of view are arranged.

Matters needing attention when using infrared thermometer:

1. Only the surface temperature is measured. The infrared thermometer cannot measure the internal temperature.

2. The temperature cannot be measured through quartz glass with a wavelength above 5um. The glass has very special reflection and transmission characteristics, which does not allow accurate infrared temperature readings. However, the temperature can be measured through an infrared window. Infrared thermometers are best not used for measuring the temperature of shiny or polished metal surfaces (stainless steel, aluminum, etc.).

3. Locate the hot spot. To find the hot spot, the instrument aims at the target, and then scans up and down on the target until the hot spot is determined.

4. Pay attention to environmental conditions: steam, dust, smoke, etc. It blocks the optical system of the instrument and affects accurate temperature measurement.

5. Ambient temperature. If the thermometer is suddenly exposed to a temperature difference of 20 ° C or higher, allow the instrument to adjust to the new ambient temperature within 20 minutes. ^[2]