Level measurement
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I encountered such a problem: the liquid level in the liquid nitrogen storage tank is stable during the day, but it gradually drops at night. I checked the transmitter and pressure transduction tubes and found no leaks. I would appreciate it if experts could help analyze the reason for this. (This does not happen in summer; it only occurs in winter.)
There may be other media inside the pressure guiding tube; it is recommended to open the drain valve for purging, and also open the transmitter’s air release valve for purging.
I guess it’s because the temperature is low at night, causing the volume of the liquid in the tank to decrease (due to the principle of thermal expansion and contraction).
Double flange? The several double-flange units we installed in 2007 often failed as winter set in, especially during the cold nights. I think it’s because the filling liquid inside is impure (we should be using silicone oil).
The problem here is that it’s during the day; local vaporization of liquid ammonia causes the float to become unstable. In any case, since it’s unstable, we choose to drain the liquid, or we can try covering it with insulating material
Heat tracing was also applied, but the effect was not significant.
All of these have been tried, but still there’s no effect.
This is a differential pressure transmitter; I’ve tried cleaning it and providing heat tracing, but it still doesn’t work properly.