The measurement data error of single-flange differential pressure level gauges is very large
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The two storage tanks in the on-site tank farm are each 5 meters in height; they are open-top containers. A single-flange differential pressure level gauge has been installed at the bottom of these tanks, but the measurement values are not accurate. The range indicated on the gauge’s nameplate is 0–5 meters. I’m not sure what’s causing this issue and how to resolve it. Please help!
I think the density of the pressure vessel at normal pressure is accurate, and there’s no issue with the calculated range; I suspect it’s still the inaccurate density that leads to the incorrect calculated range.
In my humble opinion, inaccurate density leads to an accurate calculated range.
Thanks for the comment; it’s probably not due to the range
It is generally caused by changes in density, crystallization at the contact points, and other issues
Besides density, are the zero point and installation position exactly the same during calibration!
Are there any debris covering the diaphragm?
A large error has little to do with the level gauge itself; at most, it’s due to slight variations in air pressure. You need to check whether there are crystals or other contaminants attached to the diaphragm. Also, whether the properties of the medium are stable matters a lot, as changes in density have a significant impact on the measurements.
The last edit to this post was made by hxch150804 on 2021-9-15 at 13:43. In general, design firms do not use single-flange designs for such differential pressure level gauges; even in the case of open tanks, the gas pressure above the liquid can remain unstable depending on the medium being handled. Some people try to use a single flange together with the pressure at the top of the tank to create a differential pressure transmitter, but this approach also results in errors and fails to achieve the speed of operation expected from a proper differential pressure transmitter
I suggest you take a look at medium density, diaphragm boxes, and zero point as well