Problems with electromagnetic flowmeters
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Three new electromagnetic flowmeters were installed, one in each of two PVC pipes (one horizontal and one vertical) and one in a stainless steel pipe (vertical). After installation, the electromagnetic fluctuation amplitude on the vertical PVC pipe was relatively large, while those on the other two were normal. The flow meter is working properly. The wiring is correct. The PVC pipes are not bridged. I would like to ask the experts: what other factors are there? It is a split-type electromagnetic flowmeter. This post was last edited by marry on 2009-4-16 at 15:08.]
Regarding LZ’s comment that \"the electromagnetic fluctuations on PVC pipes are relatively large,\" it is suggested that the original poster be more specific, for example, what medium is being measured by the electromagnetic flowmeter used? Are there any high-power devices surrounding the installed electromagnetic flowmeter, is the grounding of the device proper, and is the medium being measured in a full-bucket condition?
Is it because the flow medium is sometimes not full of the pipe and sometimes is?
What is your medium? Is the flow direction of the medium from bottom to top?
It’s probably not a grounding jumper issue; it’s also possible that the tube isn’t filled to capacity, as the horizontal parts are fine
What is the medium in an electromagnetic flowmeter? In what direction is the flow for an inaccurate flow meter? Is it possible to do this when the pipe is full? There should be no interfering factors in the surrounding environment, as the other two flow meters are working properly.
Could static electricity generated by the fluid in the pipeline interfere with the electromagnetic flowmeter?
Our company also has many electromagnetic flowmeters, and vertical-mounted flowmeters have experienced significant fluctuations in flow indication as well. One unit was found to have excessive pipe vibration during on-site inspection, especially when the pump upstream of it started operating; gas in the fluid is likely to be the cause of this pipe vibration and flow rate fluctuations. To summarize, regarding the fluctuations in the readings of electromagnetic flowmeters, the common causes of problems are: 1. Pipeline vibration ； 2. Electromagnetic interference caused by the startup of large motors on site or other reasons ； 3. The fluid in the pipe does not fill the entire pipe ； 4. The fluid in the pipeline contains gas ； 5. Is the installation direction incorrect? The normal flow direction should be from bottom to top. I’m not sure if the above points will be helpful to LZ.
Floor 11 provides a fairly comprehensive overview. It is recommended that the original poster pay attention to the operating conditions, communicate more with the process engineers to understand the specific conditions, and then use the various scenarios mentioned above to rule them out one by one in order to determine the source of the problem.
The medium is wastewater; there are no disturbances in the surroundings, pipe vibrations are minimal, the feed pump is located far below in the pipeline, and the flow direction is from bottom to top. The inlet pipe and the outlet pipe are at the same height, resembling an inverted U. Regarding the situation described on the 11th floor, except for the inability to determine whether the medium contains bubbles, all other possibilities can be ruled out. But it’s certain that there are fewer bubbles. I was wondering if there are any other factors that could cause this situation? ?
In addition to the 11th floor, the owner also needs to consider how far the outlet on the vertical pipe is from the flow meter, whether it is open, and whether it leads straight out
Is it open-ended, or does it extend straight out? Is it related to that factor of the flow meter? Thanks for the advice...
The installation location of the flow meter, being in the center of the vertical inlet pipe – whether it is open or extends straight out – is related to factors related to the flow meter itself What conditions will it lead to? Thanks for the advice...
No ground ring is installed. However, the electromagnetic device of the other horizontal PVC pipe also did not have a grounding ring, yet it worked normally.