Differential pressure transmitter level gauge (Siemens)
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When using a differential pressure transmitter level gauge (Siemens) to measure liquid level, why does the gauge display a negative value when the liquid level exceeds the upper flange? Does the gas phase affect the level gauge?
Either you are using a pressure guide tube, and the liquid has entered the upper end of that guide tube! ! ! !
The gas phase definitely has an impact, as the pressure acting on the diaphragm is related to the density of the medium; when the density in the gas phase increases, the negative pressure becomes greater than the positive pressure, so a negative value will definitely be displayed!
Of course, it’s the liquid that enters the pressure guide tube; as a result, the pressure in the negative pressure chamber increases, which is why negative pressure is indicated
It’s possible that the range setting is incorrect. For a negative pressure system connected to the gas phase, it’s necessary to fill it with water first, and then adjust the range to a value between negative and 0. That should work. This is how we handle the liquid level in our boilers. Balance vessel used
I find it a bit far-fetched – why can it be determined that the density is higher in the gas phase than in the liquid phase? Could you explain it in detail?