Calculation of pressure check interference for double-flange level gauges in pipelines
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As the title suggests, I have an evaporator. The measurement point on the flange below the level gauge is located in the pipeline at the bottom of the evaporator; the flow rate and resistance in that pipeline have a significant impact on the accuracy of the level gauge. Is there anyone who can help solve this problem? At present, a pressure drop compensation scheme is being considered for resistance calculation
Do you mean that an evaporator is a type of non-contact heat exchanger? Since you are measuring the liquid level, why do you mention placing the pressure sensing point on the pipeline? I suggest that you change this location and place it at a spot farther away from the inlet and outlet ports, that is, in an area where the liquid level in the evaporator is more stable; this will yield more accurate results. I’m not sure about the operating principles of your equipment – does the steam flow through the tube side? Does the material flow through the shell side? Measure the liquid level of the material? Why use double flanges? This is a chemical material – what are its properties?
Are the measurement values too low? Let the process give you a chance: at the normal liquid level, read the DP values under both \"flowing\" and \"non-flowing\" conditions; the difference between these values is approximately equal to the magnitude of the flow resistance loss. Migrate it to measure the liquid level. The small measurement range, combined with the capillary design, limits the accuracy of the measurements.
Errors in the measured DP occur due to the difference in liquid surface pressure under static and dynamic conditions.
It cannot be changed – it’s special material and equipment, and it has already been manufactured. The material flows through the tube side, while steam flows through the shell side.
The device outlet cannot be changed; level detection is feasible after attempting to adjust the flow rate.
It doesn’t matter how thick the pipe you use for this purpose; there are many factors that can cause errors. If the interference is a constant, then it’s easier to deal with it – you can calculate it and subtract it from the readings. But I think in your case it’s definitely not a constant. When the liquid level is high, the error should be small, while it increases when the liquid level is low. This is a difficult problem to solve. It shows that those who design the equipment do it carelessly, treating the instruments as something unimportant; this is the result of not considering the instruments at all. I really can’t do anything; I’m sorry, I can’t help you.
This post was last edited by sdrp on 2021-11-12 at 11:12; it’s indeed not easy to handle
It is recommended to try using a high-temperature external-mounted level gauge.
You are right; there are many sources of error and interference. The best approach at present is to consider using an inserted pressure sensing method to solve this problem, although the implementation process is quite complex.
This is something to consider. Does the manufacturer have any recommendations?