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The Seven Elements of the Buy ir pyrometer

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The Seven Elements of the Buy ir pyrometer

(Summary description)As technology continues to evolve, advances in ir pyrometer technology provide users with a variety of functional and versatile instruments that expand their options.

The Seven Elements of the Buy ir pyrometer

(Summary description)As technology continues to evolve, advances in ir pyrometer technology provide users with a variety of functional and versatile instruments that expand their options.

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As technology continues to evolve, advances in ir pyrometer technology provide users with a variety of functional and versatile instruments that expand their options. In the Buy ir pyrometer model, the measurement requirements should be determined first, such as the temperature of the target to be measured, the size of the target to be measured, the measurement distance, the material of the target to be measured, the environment of the target, the response speed, the measurement accuracy, whether it is portable or online, etc.; In the comparison of various existing models of ir pyrometer, the instrument model that can meet the above requirements is selected; among many models that can meet the above requirements, the best match in terms of performance, function and price is selected. Other options, such as ease of use, maintenance and calibration performance, etc.

ir pyrometer

1. Determine the temperature measurement range
Determine the temperature measurement range: The temperature measurement range is the most important performance indicator of the ir pyrometer. Each model 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 of radiant energy caused by temperature in the short waveband of the spectrum will exceed the change of radiant energy caused by the emissivity error. Generally speaking, the narrower the temperature measurement range is, the higher the resolution of the output signal of the monitored temperature is, and the accuracy and reliability are easy to solve. If the temperature measurement range is too wide, the temperature measurement accuracy will be reduced.

2. Determine the target size
In order to obtain accurate temperature readings, the distance between the ir pyrometer and the test target must be within a suitable range. The so-called "spot size" is the area of ​​the measuring point of the ir pyrometer. The further away you are from the target, the larger the spot size.
According to the principle, ir pyrometer can be divided into monochromatic ir pyrometer and two-color ir pyrometer (radiation colorimetric ir pyrometer). For a monochromatic ir pyrometer, the measured target area should fill the ir pyrometer's field of view when measuring temperature. It is recommended that the size of the target to be measured exceed 50% of the size 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 ir pyrometer's audio-visual branch to interfere with the temperature measurement reading, causing errors.
Conversely, if the target is larger than the ir pyrometer's field of view, the ir pyrometer will not be affected by the background outside the measurement area. For a colorimetric ir pyrometer, the temperature is determined by the ratio of the radiant energy in two separate wavelength bands. Therefore, when the measured target is small and does not fill the field of view, and the presence of smoke, dust, or obstructions on the measurement path will attenuate the radiant energy, it will not affect the measurement results. The required temperature measurement accuracy can be guaranteed even when the energy is attenuated by 95%.
For small, moving or vibrating targets, the colorimetric ir pyrometer is the best choice. This is due to the small diameter of the light and its flexibility to transmit optical radiation energy in curved, blocked and folded channels, thus enabling measurements of targets that are difficult to access, harsh conditions or close to electromagnetic fields.

3. Determine the distance factor (optical resolution)
The distance factor is determined by the ratio of D:S, which is the ratio of the distance D between the ir pyrometer probe to the target and the diameter of the target being measured. The higher the optical resolution, that is, the higher the D:S ratio, the higher the cost of the ir pyrometer. If the ir pyrometer must be installed away from the target due to environmental conditions, and small targets are to be measured, an ir pyrometer with high optical resolution should be selected.
For the ir pyrometer with fixed focal length, the spot is the smallest position at the focal point of the optical system, and the spot will increase near and far from the focal position. There are two distance coefficients. Therefore, in order to accurately measure the temperature at the distance close to and far from the focus, the size of the target to be measured should be larger than the size of the spot at the focus. The zoom ir pyrometer 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, it is difficult to increase the distance coefficient D: S, which will increase the cost of the instrument.

4. Determine the wavelength range
The emissivity and surface properties of the target material determine the corresponding wavelength of the ir pyrometer's spectrum. For high reflectivity alloy materials, there are low or varying emissivity. In the high temperature region, the best wavelength for measuring metal materials is near-infrared, and 0.8-1.0 μm can be selected. Other temperature zones can choose 1.6μm, 2.2μm and 3.9μm. Since some materials are transparent at certain wavelengths, infrared energy will penetrate these materials, and special wavelengths should be selected for this material.
For example, the wavelengths of 1.0μm, 2.2μm and 3.9μm (the glass to be measured should be very thick, otherwise it will pass through) are selected for measuring the internal temperature of the glass; 5.0μm is selected for measuring the surface temperature of the glass; For example, 3.43μm is used for measuring polyethylene plastic film, 4.3μm or 7.9μm for polyester, and 8-14μm for thickness exceeding 0.4mm. For example, the narrow band of 4.64μm is used to measure CO in the flame, and 4.47μm is used to measure the NO2 in the flame.

5. Determine Response Time
The response time is defined as the time required to reach 95% of the energy of the last reading, indicating the response speed of the ir pyrometer to the temperature change under test, which is related to the time constant of the photodetector, signal processing circuit and display system. The selection of the response time of the ir pyrometer should be adapted to the situation of the measured target, and the response time is determined mainly according to the movement speed of the target and the temperature change speed of the target.
If the moving speed of the target is very fast or when measuring a rapidly heated target, a fast-response ir pyrometer should be used, otherwise, the sufficient signal response will not be achieved, which will reduce the measurement accuracy. However, not all applications require a fast-response ir pyrometer. For stationary or thermal inertia of the target thermal process, the response time requirement can be relaxed.

6. Signal processing function
In view of the difference between discrete processes (such as parts production) and continuous processes, the ir pyrometer is required to have multiple signal processing functions (such as peak hold, valley hold, average value) to choose from, such as when measuring bottles on a conveyor belt, it is necessary to use Peak hold, the output signal of its temperature is sent to the controller. Otherwise the ir pyrometer reads the lower temperature value between the bottles. If using peak hold, set the ir pyrometer response time to be slightly longer than the time interval between bottles so that at least one bottle is always under measurement.

7. Environmental conditions to consider
The environmental conditions in which the ir pyrometer is located have a great influence on the measurement results, which should be considered and properly resolved, otherwise it will affect the temperature measurement accuracy or even cause damage. When the ambient temperature is high and there is dust, smoke and steam, accessories such as protective cover, water cooling, air cooling system, and air blower provided by Guangzhou Huahong Automation Equipment Co., Ltd. can be selected. These accessories effectively address environmental influences and protect the ir pyrometer for accurate temperature measurement.
When identifying accessories, standardised services should be required wherever possible to reduce installation costs. The fiber optic two-color ir pyrometer is the best choice when smoke, dust, or other particles degrade the measured energy signal under noise, electromagnetic fields, vibration, or inaccessible ambient conditions, or other harsh conditions. In noise, electromagnetic field, vibration and inaccessible environmental conditions, or other harsh conditions, light colorimetric ir pyrometer should be selected.
 

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