Correctly choose the method of infrared thermometer
Since there are many series and models of infrared thermometers, each model has its own parameters, performance and functions, such as temperature measurement range, optical resolution (distance coefficient), working wavelength, response time, working environment conditions and signal processing output display method etc. Therefore, it is very important for users to choose the correct infrared thermometer model. The correct choice of infrared thermometer requires mastering "three elements and three principles".
Three elements:
1/Target temperature range:
The temperature measurement range of the infrared thermometer is generally determined by the temperature of the measured target. If the maximum temperature of the measured target is 800°C and the minimum is 250°C, then we can choose one that is slightly higher than the upper limit and slightly lower than the lower limit. Appropriate temperature range.
2/ Target size and measurement distance:
The ratio of the measurement distance to the target diameter - the distance coefficient (D:S) is a very important parameter of the infrared thermometer, "D" refers to the measurement distance, and "S" refers to the diameter of the target. If the D:S of an infrared thermometer is 8:1, that is to say: the size of a measured target is 1 unit, then the infrared thermometer can be accurate within a distance of 8 units of the measured target size. Measurement, as shown below:
If it is greater than 8 units, the infrared energy radiated by the target cannot be received by the infrared thermometer due to the distance is too far away, and the temperature will deviate, so the size of the target should be greater than or equal to the site of the thermometer. It is recommended that the measured target size exceed 50[%] of the pyrometer's field of view. Then as shown below:
If the thermometer is far away from the target and the target is small, a thermometer with a high distance coefficient should be selected.
3/ Target material:
When any object has a certain temperature (above -273°C), it will emit infrared energy outward, but different substances have different radiation capabilities, so the material of the target is also an important reference for choosing infrared temperature measurement. We call it Emissivity "∈", if measuring the temperature of non-metallic objects, then ∈ is generally 0.95, if it is measuring the temperature of metal, you need to adjust "∈"
Three principles:
1/Requirement principle: First of all, the measurement requirements and the problems to be solved must be clarified, such as: 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 requirements, the accuracy requirements, etc.
2/Comparison principle: compare the measurement requirements and the problems to be solved with the existing various thermometers, and select the instruments that can meet the above requirements.
3. Matching principle: Choose the best match in terms of performance, function and price among various models that can meet the requirements.
