Process Engineering Division – Instrumentation and Automation Section – Daily Question – Question from 2020-11-03
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This post was last edited by It will be better tomorrow on 2020-11-3 08:33 in the Process Engineering Section – Instrumentation and Automation Section – Daily Question – Question No. 2020-11-03. Discussion topic: 285. When using radar to measure liquid level, if there is a thick layer of foam on top of the liquid (with tiny particles mixed in the foam), how should the frequency be adjusted? (Extra points for a thorough discussion from a principled perspective)
A level gauge with an insertion tube can be chosen; radar waves are sent through this thin tube, and the liquid level inside the tube is the same as that outside and remains relatively stable
I think the most effective approach is not to increase or decrease the wavelength; using a waveguide might avoid this problem, and theoretically reducing the wavelength could lessen interference.
Increase the frequency. Since the foam layer together with the small particles absorbs a certain amount of electromagnetic wave energy, it is only by increasing the frequency and thus the emitted energy that it is possible to ensure that enough energy is returned to be detected.
Foam caused by feed splashing or foam mixed in the medium has no effect on the reflection of radar waves. For media with less foam, specialized radars (high-frequency) such as guided wave radars or guided rod radars can be used for measurement; by selecting \"media foam\" in the medium options, it is possible to obtain more accurate readings of the liquid level in media containing foam.
Increase the frequency. Since the foam layer together with the small particles absorbs a certain amount of electromagnetic wave energy, it is only by increasing the frequency and thus the emitted energy that it is possible to ensure that enough energy is returned to be detected.
Increase the frequency, because for foam-containing level measurement: foam caused by feed splashing or foam mixed in the medium has no effect on the reflection of radar waves. For some media with less foam, using a dedicated radar for measurement and selecting \"media foam\" in the media options allows for more accurate measurement of the liquid level in such foamy conditions. However, the large amount of thick foam generated by intense chemical reactions absorbs and scatters radar waves, resulting in poor echo quality.
The frequency should be increased. It enhances the penetration of radar waves, allowing them to pass through foam layers and thus enabling normal use
Increase the frequency, because for foam-containing level measurement: foam caused by feed splashing or foam mixed in the medium has no effect on the reflection of radar waves. For some media with less foam, using a dedicated radar for measurement and selecting \"media foam\" in the media options allows for more accurate measurement of the liquid level in such foamy conditions. However, the large amount of thick foam generated by intense chemical reactions absorbs and scatters radar waves, resulting in poor echo quality.