Selection of Handheld Thermometer and Portable Hardness Tester
Performance indicators, such as temperature range, spot size, working wavelength, measurement accuracy, response time, etc.; environmental and working conditions, such as ambient temperature, window, display and output, protection accessories, etc.; other options, such as ease of use, maintenance And calibration performance and price, etc., also have a certain impact on the choice of thermometer. With the continuous development of technology and technology, the best design and new progress of infrared thermometers provide users with various functions and multi-purpose instruments, expanding the choice.
1 Determine the temperature measurement range
The temperature measurement range is the most important performance index of the thermometer. For example, INFR (Infrared Times), Raytek (Raytek) products cover the range of -50°C-+3000°C, but this cannot be done by 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 accurately and comprehensively, neither too narrow nor too wide. According to the law of blackbody radiation, in the short-wave band of the spectrum, the change of radiation energy caused by temperature will exceed the change of radiation energy caused by emissivity error. Therefore, it is better to use short-wave as much as possible when measuring temperature. Generally speaking, the narrower the temperature measurement range is, the higher the resolution of the output signal of the temperature monitoring 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. 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 Ti315, Ti213 and so on.
2 Determine the target size
Infrared thermometers can be divided into single-color thermometers and two-color thermometers (radiation colorimetric thermometers) according to the principle. For monochromatic thermometers, when measuring temperature, the area of the target to be measured should fill the field of view of the thermometer. It is recommended that the measured target size exceed 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 symbols of the thermometer and interfere with the temperature measurement readings, causing errors. Conversely, if the target is larger than the pyrometer's field of view, the pyrometer will not be affected by background outside the measurement area. For a two-color thermometer, the temperature is determined by the ratio of radiant energy in two independent wavelength bands. Therefore, when the target to be measured is small, does not fill the site, and there is smoke, dust, or obstruction on the measurement path that attenuates the radiation energy, it will not affect the measurement results. Even in the case of 95% energy attenuation, the required temperature measurement accuracy can still be guaranteed. For targets that are small and moving or vibrating; sometimes move within the field of view, or may partially move out of the field of view, under these conditions, the use of a two-color thermometer is the best choice. If it is impossible to aim directly between the thermometer and the target, and the measurement channel is bent, narrow, obstructed, etc., the dual-color fiber optic thermometer is the best choice. This is due to its small diameter, flexibility, and ability to transmit optical radiant energy over curved, blocked, and folded channels, thus enabling measurement of targets that are difficult to access, in harsh conditions, or near electromagnetic fields. Selection of Handheld Infrared Thermometer and Portable Hardness Tester
3 Determining Optical Resolution
The optical resolution is determined by the ratio of D to S, which is the ratio of the distance D between the pyrometer to the target and the diameter S of the measuring spot. For example, the handheld infrared thermometer Ti213 of the infrared era has a distance coefficient of 80:1. If it is 80 cm away from the target, the diameter of the measurement range is 1 cm. If the thermometer must be installed far away from the target due to environmental conditions, and a small target must be measured, a thermometer 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 thermometer.
