Air accumulation in double-flange level gauges
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Air accumulation on the upper flange of a double-flange level gauge causes the measured value to be either too high or too low; what is the reason?
Your question is a bit vague; please provide more details. What liquid level are you measuring? Shouldn’t you gather energy when going to France? Unless the wedge flowmeter flange is installed on top, gas collection is not possible.
This is used for measuring liquid level; there is already liquid above the upper flange, but bubbles are present at the connection between the upper flange and the equipment.
So, how does this double-flange level gauge measure the liquid level? The medium pressure has exceeded the negative pressure threshold; the liquid level is at the full scale, showing the maximum value. I don’t understand what sense there is in using it in this way
Beyond the upper flange, it loses its meaning for measurement. However, during the rise in liquid level, as long as it has not reached the full scale, I think there should be no problem with liquid level measurement. Also, what level do you keep the liquid at? What’s the point if it always needs to be at full scale? If it is kept around 75%, an alarm should have been set off long ago if it exceeded 95%.
With this installation method, if it is used to measure the interface or density, the liquid level must always remain above the upper flange； If used to measure liquid level, the liquid level should be kept below the upper flange. In other words, there should be no issue of the phase being either gaseous or liquid at the upper flange; if such a situation occurs, it indicates abnormal process operation. The diameter of the pressure lead pipe section at the flange should be roughly the same as that of the measuring diaphragm (φ80 or larger); this way, there will be no risk of air blockage ； If a thin tube is used to connect the flange and then the instrument, the purpose of using a flanged level gauge is lost, and it also leads to air remaining trapped near the flange surface. At this time, the pressure lead pipe section should be kept horizontal or slightly inclined downward (with the equipment side being slightly higher) to facilitate gas discharge. If gas accumulation still occurs, there is no solution (it is a design issue). The pressure tapping section or measurement method should be modified.
The liquid level has exceeded the upper flange – can the liquid level still be measured accurately?