What are the reasons for large fluctuations in the readings of thermal gas mass flow meters?
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Background information on the on-site operating conditions: 1. A main compressed air pipeline delivers air in both left and right directions to the downstream end points where it is used. 2. The exhaust volume of the on-site air compressor is stable, with it operating at near full load. 3. Two thermal gas mass flow meters are used to measure the compressed air flow rate in the main pipeline. Problem description: The instantaneous values of the flow meter fluctuate excessively, rising from 5400 m3/h to around 4000 m3/h within 1–2 seconds; another gauge’s reading drops from 1100 to 0. What could be the possible causes? Waiting online, thank you all.
Hehe, it’s really hot in there – well deserved! Congratulations. . . . . . It has a hop count; you use that hop count, and it’s destined to end in failure. No, thanks, I ha
As long as there are large variations in gas contamination and moisture levels, choosing a thermal type will lead to disaster!
Little brother, as for temperature, even if it changes quickly, it can only do so gradually; it’s impossible for the temperature to change drastically in just 1 or 2 seconds, right? As for your thermal flow meter, it uses temperature values to calculate the flow rate; the flow rate can change by over 1,000 cubic meters per hour every second or two. Hehe, what does that indicate? It shows that its temperature sensing probe is simply idiotic, a complete mess... A stupid probe usually means that the hardware part of the instrument used for data collection is poorly designed, and the software for the flow meter is even worse – the software used in such devices isn’t even capable of implementing basic functions like noise suppression to hide their flaws. Your thermal flow meter is truly stupid; it could serve as a perfect example of poor design. . :lol
Analyze the problem from three perspectives: first, check whether there are any sudden changes in the pipeline or the gas being measured; don’t assume anything – conduct tests yourself. Second, check whether there are any major sources of vibration at the site that could affect the pipelines and equipment. The first two points mentioned above are fine. I have no experience in this area, but I hope my insights can help you determine whether there are any issues with the instrument’s zero drift or performance
First, check whether there are any sudden changes in the pipeline and the gas being measured; don’t assume anything – test it yourself. Excuse me, how do I measure it?
This requires on-site experience; it can’t be explained in just a few words
It’s really unnecessary to spend extra money on two orifice plates.
We also have useful thermal types, used at the outlet of boiler blowers; they have a pipe diameter of 1500 mm, are of the insert-type thermal design, and are from E+H – offering decent stability and accuracy. Was it installed here exactly according to the instructions? Compressed air often contains a significant amount of water, and this can have a serious impact on thermal flow meters. Has the compressed air in the poster’s case been dehydrated? You can also increase that damping and see the effect.
The damping increases by 30 from 2, reaching the maximum damping value; it doesn’t have much effect. I’ll look into why this is happening
For orifice plate flowmeters, nowadays, thermal mass flowmeters are more commonly used for measuring compressed air when the pipe diameter is not too large; they are easy to install and maintain, and offer high accuracy. Logically, compared to a constant temperature difference, a temperature difference is not as susceptible to zero-point drift caused by moisture, oil, and contaminants