Magnetic flap level gauge
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For liquefied hydrocarbon storage tanks, the magnetic flap level gauge features a float inside the bulb whose position corresponds to the actual liquid level; it moves up and down properly with the level, and the color strip on the panel displays correctly below the actual liquid level. However, the red and white columns on the panel above the liquid level showed disorderly readings; after using a magnet brush on site, the disorder reappeared the next day. A new panel was installed some time ago, and in less than 2 weeks, the color bars above the liquid level started to display incorrectly again. Has everyone encountered this situation, and what are the reasons and how should it be handled?
This post was last edited by Qiushui Han Guang on 2023-2-1 at 14:32. Based on your description, it’s highly likely that the panel is not the problem, but it cannot be ruled out completely – what if there are issues with both? So there are only two remaining reasons: 1. The float’s magnetism is not strong enough; replace it. 2. The level fluctuations are too large, or it drops and rises too quickly; this issue needs to be addressed from a process perspective.
Thank you for your feedback! The actual liquid level showed almost no change; production and usage were minimal during this period, and the liquefied hydrocarbon tank was equipped with another differential pressure level gauge, so there was no significant variation in the level curve. The problem now is that the color bars on the panel above the liquid level show irregular patterns (alternating red and white), but the color bars below the actual liquid level are all red, which is normal; this should have nothing to do with the magnetism of the float.
You can check the historical trend of the DCS level gauge; there should be fluctuations in the level shown in that trend. This is caused by the vaporization of the liquid inside the float. A cooling coil can be added to the magnetic flap level gauge, or the sleeve of the magnetic flap level gauge can be replaced with one that has a jacket.
Thank you for your feedback! The jump caused by vaporization can explain this phenomenon. I would like to ask: for liquefied hydrocarbon media that are prone to vaporization, isn’t it common to use floaters for magnetic flap level gauges that come with jackets? This can reduce the impact of vaporization jumps; it is a matter of selection
This post was last edited by xlxuiin on 2023-2-2 at 12:23. We have newly installed a tank on-site; it has not been used yet (no medium inside), and the display of the magnetic flap level gauge is also chaotic. It seems there might be magnetic interference between the magnetic plates of the panel?
Before using it for the first time, use a magnet to restore the panel color columns to their normal state; first open the valve at the bottom to feed material in slowly
Check whether there is any interference around the level gauge