8 tips for purchasing an infrared thermometer

8 tips for purchasing an infrared thermometer
How to choose the correct infrared thermometer
The choice of infrared thermometer can be divided into three aspects:
(1) 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, protective 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 the technology and continuous development, the best design and new development of infrared thermometers provide users with a variety of functions and versatile instruments, expanding the choice. Other options, such as ease of use, repair and calibration performance, and price. When selecting the thermometer model, you should first determine the measurement requirements, such as the target temperature to be measured, the target size to be measured, the measurement distance, the target material to be tested, the environment in which the target is located, the response speed, the measurement accuracy, whether it is portable or online, etc. In the comparison of various types of thermometers, select the model that meets the above requirements; choose the best combination of performance, function and price among the models that can meet the above requirements.
1, determine the temperature range
Determining the temperature range: The temperature range is one of the most important performance indicators of the thermometer. For example, Raytek's product coverage ranges from -50°C to +3000°C, but this cannot be done with a model 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 black body radiation law, the change of the radiant energy caused by the temperature in the short wavelength band of the spectrum will exceed the change of the radiant energy caused by the emissivity error. Therefore, it is better to select the short wave when measuring the temperature. In general, the narrower the temperature measurement range, the higher the resolution of the output signal of the monitoring temperature, and the accuracy and reliability are easily solved. If the temperature range is too wide, the temperature measurement accuracy will be lowered. For example, if the target temperature is 1000 ° C, first determine whether it is online or portable, if it is portable. There are many models that meet this temperature, such as 3iLR3, 3i2M, and 3i1M. If the measurement accuracy is the main one, it is best to use 2M or 1M models, because if the 3iLR type is used, the temperature measurement range is very wide, then the high temperature measurement performance is worse; if the user has to measure the target of 1000 °C, take care of Low temperature target, then I have to choose 3iLR3.
2, determine the target size
According to the principle, the infrared thermometer can be divided into a monochrome thermometer and a two-color thermometer (radiation colorimeter). For a monochrome thermometer, the measured target area should be filled with the field of view of the thermometer when measuring temperature. It is recommended that the measured target size exceeds 50% of the field of view size. If the target size is smaller than the field of view, the background radiant energy will enter the thermometer's visual accumulator to interfere with the temperature reading, causing an error. 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 colorimetric thermometers, the temperature is determined by the ratio of the radiant energy in two independent wavelength bands. Therefore, when the measured target is small and does not fill the field of view, there is smoke, dust, and blockage on the measurement path, and when the radiation energy is attenuated, it does not have a significant impact on the measurement result. Colorimetric thermometers are the best choice for small, moving or vibrating targets. This is due to the small diameter of the light and the flexibility to transmit optical radiant energy on curved, blocked and folded channels.
For the Raytek two-color thermometer, the temperature is determined by the ratio of the radiant energy in two independent wavelength bands. Therefore, when the measured target is small, there is no full scene, there is smoke, dust and blocking on the measurement path, and the radiation energy is attenuated, and the measurement result will not be affected. Even when the energy is attenuated by 95%, the required temperature measurement accuracy can be guaranteed. For targets with small targets that are in motion or vibration; sometimes moving within the field of view, or possibly partially moving out of the field of view, under these conditions, the use of a two-color thermometer is the best choice. A two-color fiber optic thermometer is the best choice if there is no direct aiming between the thermometer and the target, and the measurement channel is curved, narrow, and obstructed. This is due to its small diameter and flexibility to transmit optical radiant energy over curved, blocked and folded channels, so that it is possible to measure targets that are difficult to access, have harsh conditions, or are 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 between the probe probe to the target and the diameter of the target to be measured. If the thermometer must be installed away from the target due to environmental constraints, but to measure small targets, you should choose a high optical resolution thermometer. The higher the optical resolution, i.e. increasing the D: S ratio, the higher the cost of the thermometer. The Raytek infrared thermometer D:S ranges from 2:1 (low distance factor) to above 300:1 (high distance factor). If the thermometer away from the target, and the target and small, should be chosen high thermometer distance coefficient. For a fixed focal length thermometer, the spot is at the minimum position at the focus of the optical system, and the spot is increased near and farther than the focus. There are two distance coefficients. Therefore, in order to accurately measure the temperature at a distance close to and away from the focus, the size of the measured object should be larger than the spot size at the focus. The zoom thermometer has a minimum focus position that can be adjusted according to the distance to the target. When D:S is increased, the received energy is reduced. If the receiving aperture is not increased, the distance coefficient D:S is difficult to increase, which increases the instrument cost.
4, determine the wavelength range
The emissivity and surface characteristics of the target material determine the spectrally corresponding wavelength of the thermometer for low reflectivity alloy materials with low or varying emissivity. In the high temperature zone, the optimum wavelength for measuring the metal material is near-infrared, which can be selected from 0.8 to 1.0 μm. Other temperature zones are available in 1.6μm, 2.2μm and 3.9μm. Since some materials are transparent at a certain wavelength, infrared energy will penetrate these materials, and a particular wavelength should be chosen for this material. For example, the internal temperature of the measuring glass should be 1.0μm, 2.2μm and 3.9μm (the glass to be tested should be very thick, otherwise it will pass through); the surface temperature of the glass should be 5.0μm; the low temperature range should be 8~14μm. For example, the measurement of polyethylene plastic film is 3.43 μm, the polyester type is 4.3 μm or 7.9 μm, and the thickness is more than 0.4 mm, which is 8-14 μm. For example, if the CO in the flame is narrowband 4.64 μm, the NO2 in the flame is 4.47 μm.
5, determine the response time
The response time represents the response speed of the infrared thermometer to the measured temperature change, defined as the time required to reach 95% of the final reading, which is related to the time constant of the photodetector, signal processing circuitry, and display system. Raytek's new infrared thermometers have a response time of up to 1ms. This is much faster than the contact temperature measurement method. If the target moves quickly or measures a fast-heating target, use a fast-response infrared thermometer. Otherwise, sufficient signal response will not be achieved, which will reduce the measurement accuracy. However, not all applications require a fast-responding infrared thermometer. For thermal inertia in stationary or target thermal processes, the response time of the thermometer can be relaxed. Therefore, the response time of the infrared thermometer should be selected in accordance with the situation of the target. The response time is determined mainly based on the moving speed of the target and the temperature change rate of the target. For a stationary target or target to participate in thermal inertia, or the speed of existing control equipment is limited, the response time of the thermometer can be relaxed.
6, signal processing function
In view of the fact that discrete processes (such as parts production) and continuous processes are different, infrared thermometers are required to have multiple signal processing functions (such as peak hold, valley hold, average), such as when measuring bottles on a conveyor belt. To maintain with peak, the output signal of its temperature is transmitted to the controller. Otherwise the thermometer reads the lower temperature value between the bottles. If peak hold is used, set the thermometer response time to be slightly longer than the time interval between the bottles so that at least one of the bottles is always in the measurement.
7. Environmental conditions are considered
The environmental conditions in which the thermometer is located have a great influence on the measurement results and should be considered and properly resolved. Otherwise, the temperature measurement accuracy or even damage will be affected. When the ambient temperature is high and there are dust, smoke and steam, you can use the manufacturer's protective cover, water cooling, air cooling system, air purifier and other accessories. These accessories effectively address environmental impacts and protect the thermometer for accurate temperature measurement. When determining attachments, standardization services should be required as much as possible to reduce installation costs. A fiber optic two-color thermometer is the best choice when reducing smoke, dust, or other particles in a noise, electromagnetic field, vibration, or inaccessible environment, or other harsh conditions. Colorimetric thermometers are the best choice. In the case of noise, electromagnetic fields, vibrations and inaccessible environmental conditions, or other harsh conditions, a light colorimetric thermometer should be selected.
In sealed or hazardous material applications (eg containers or vacuum boxes), the thermometer is observed through a window. The material must have sufficient strength and the thermometer can use the operating wavelength range. Also determine if the operator also needs to observe through the window, so choose the appropriate mounting location and window material to avoid mutual influence. In low temperature measurement applications, Ge or Si materials are often used as windows, which are not transparent to visible light, and the human eye cannot observe the target through the window. The operator needs the target through the window, both should be transparent infrared radiation and visible light through optical materials, such as infrared radiation should be both transparent and permeable to visible light and other optical materials, such as ZnSe or BaF2 as a window material.
When there is a flammable gas in the working environment of the thermometer, an intrinsically safe infrared thermometer can be selected to perform safety measurement and monitoring in a certain concentration of flammable gas environment.
In the case of harsh environmental conditions, a separate system of temperature probes and displays can be selected for ease of installation and configuration. A signal output form that matches the current control device can be selected.
8. Calibration of infrared radiation thermometer

The infrared thermometer must be calibrated to correctly display the temperature of the target being measured. If the thermometer used is out of temperature, it needs to be returned to the factory or repair center for recalibration.

Santoku Knife

Steel Kitchen Santoku Knife,Kitchen Santoku Knife,Professional Santoku Knife,Metal Santoku Knife

GUANGDONG INWIN INDUSTRIAL GROUP CO. ,LTD. , https://www.inwin1979.com

Posted on