Infrared thermometer according to the principle of distance coefficient analysis and distance coefficient analysis
Infrared thermometer according to the principle can be divided into monochrome pyrometer and two-color pyrometer (radiation colorimetric pyrometer). For single-color pyrometer, in the temperature measurement, the measured target area should be filled with pyrometer field of view. It is recommended that the 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 pyrometer's visual acoustic signature to interfere with the temperature reading, resulting in errors. Conversely, if the target is larger than the pyrometer's field of view, the pyrometer 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 separate wavelength bands. Therefore, when the measured target is small and does not fill the field of view, the presence of smoke, dust, obstruction on the measurement path, there is attenuation of the radiant energy, are not significant impact on the measurement results. For small and in motion or vibration of the target, colorimetric thermometer is a good choice. This is due to the small diameter and flexibility of the light, which allows the transmission of optical radiation energy in curved, blocked and folded channels.
Infrared thermometer according to the principle and distance coefficient analysis
What is the distance coefficient of infrared thermometer? Distance coefficient is determined by the ratio of D:S, that is, infrared thermometer pyrometer probe to the target between the distance D and the diameter of the target being measured ratio. If the pyrometer must be installed far from the target due to environmental conditions, but also to measure small targets, you should choose a high optical resolution pyrometer.
The higher the optical resolution, i.e., increasing the D:S ratio, the higher the cost of the pyrometer. Infrared thermometer D:S ranges from 2:1 (low distance factor) to higher than 300:1 (high distance factor). If the pyrometer is far from the target and the target is small, you should choose an infrared thermometer thermometer with a high distance factor.
For fixed focal length pyrometer, in the optical system at the focal point for the spot small position, near and far from the focal point position spot will increase, there are two distance coefficients. Therefore, in order to be able to accurately measure temperature near and far from the focal point of the distance, the size of the target to be measured should be larger than the spot size at the focal point;
The zoom pyrometer has a small focal spot position that can be adjusted according to the distance to the target. Increase D:S, the received energy is reduced, if not increase the receiving aperture, the distance coefficient D:S is difficult to make larger, which should increase the cost of the instrument.
