Selection of double-flange level gauges
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I would like to ask everyone: for tanks in process equipment that have exhaust pipelines, when is it necessary to use double flanges and when should single flanges be used? Or, can a single-flange level gauge always be used as long as the process equipment operates at atmospheric pressure?
To use a single-flange level gauge, it is necessary to ensure that normal pressure is always maintained. Some devices are labeled as operating under normal pressure, but the process may generate negative or positive pressure; therefore, this must be confirmed.
A single-flange level gauge can only be used when the tank is continuously exposed to the atmosphere; if the tank is sealed or only intermittently sealed, a double-flange level gauge must be used
In addition to pressure, attention should also be paid to changes in density
The tank must be at atmospheric pressure at all times in order to use a single-flange level gauge to measure the liquid level!
““Normal pressure” is a crappy term, one that’s confusing; it refers to a low level of positive or negative pressure, and for goodness’ sake, it’s still called “normal pressure”. Come on, it should either be called “open pressure”, meaning a state with open gaps and no restrictions, or “zero pressure”.
Double flanges are generally used for closed storage tanks, while single flanges are used for open storage tanks
Open containers can use a single flange, while double flanges are used for closed tanks to measure differential pressure.
If it’s not a sealed container, a single flange will suffice. Otherwise, double flanges are required. Because measuring displacement requires calculation based on the differential pressure
Currently, all pressure-rated ones use double flanges
If the density also changes, then it’s not a problem related to single flanges or double flanges, and differential pressure can no longer be used!