Cold box issue
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The liquid level in our cold boxes often shows false readings, and the staff on site no longer trusts the level indicated by the display； There is also periodic supercooling in the temperature between the two heat exchangers below the cold box ； Has this kind of situation occurred at that store before? What is the reason? How should this be handled? I thank you here.
Which brand’s meter is the one used by the poster?
False level readings may occur in this situation because, when installing the pressure guide tube of the level gauge, it is placed too far away from the cryogenic tank; as a result, liquid nitrogen vaporizes, the pressure difference becomes inaccurate, and false level readings appear. You can try to shorten the distance between the pressure guide tube and the cryostat when installing it. Periodic subcooling of the heat exchangers at the bottom of the cryogenic tank can be tried to increase the temperature between them (care must be taken with the rate – it shouldn’t be too fast; this can be achieved within three to four shifts). During this process, attention must also be paid to the temperature of the feed gas entering the nitrogen scrubber, ensuring that it remains within the specified limits.