Calibration of double-flange differential pressure level gauge
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Vertical tank, with a height difference of about 13 meters between the level gauge ports. After pressurizing, purging, and evacuating the equipment, introduce gaseous material to achieve positive pressure, then open the upper and lower valves of the level gauge to set it to zero. However, after feeding, it was found to not match the actual liquid level. Height and liquid density have both been taken into account; could it be the gas-phase density causing it? Prepare to remove the level gauge flange and reset it to zero.
I couldn’t see your situation very clearly. After the migration at 0 o’clock, I’m not sure if your range has been migrated accordingly; you’ll need to adjust the URV, right?
If the zero point is accurate, it’s likely a range issue – is the range setting consistent with the actual value?
When evacuating, is the shut-off valve in front of the liquid level transmitter flange closed? If it isn’t closed, it may cause damage to the diaphragm of the double-flange transmitter
If the zero point is accurate, it’s likely a range issue – is the range setting consistent with the actual value?
Diaphragms are generally sensitive to negative pressure; did you mention this specifically when making the purchase, as applying negative pressure is harmful to the diaphragm?
It’s very simple: when the tank is empty and under no pressure, the pressure difference inside the upper and lower diaphragms is read as a negative value, such as -113 Kpa. Set the range of the controller to from -113 Kpa to 0 Kpa, and that’s it. Note: Before use, the differential pressure level gauge must have both the upper and lower pressure diaphragms operating simultaneously. This post was last edited by jsnjhu on 2009-2-23 22:31]
Upstairs, -113 KPa represents negative migration; the range is ρgH, and it is necessary to know the density.
Check if the gasket is pressing on the diaphragm!