Vacuum pumping issues in low-temperature storage tanks
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Are there any requirements for the vacuum pumping records of low-temperature storage tanks? For example, at what vacuum level measurement should start, and how often readings should be taken, etc. I also want to ask whether the vacuum level for sealing refers to the vacuum level when the vacuum pump is turned off, or it refers to the value recorded after measuring the leak air release rate once the pump has been shut down. It should be the figure from when it was shut down, right? Because that last number keeps changing over time. . How do you determine the air leakage rate – for how long do you conduct the measurements, and how often do you take readings? .
The vacuum requirement for low-temperature storage tanks depends on the medium stored inside them; in simple terms, the lower the pressure, the better. For leak detection, it is best to use a helium mass spectrometer.
We start recording once the gauge shows a reading; we take readings once in the morning and once in the afternoon each day, and we continue to record daily for ten days after the pump is stopped. From now on, record it once or twice a week.
What material does your company use for the jacket insulation?
Thank you! The cryogenic vessels I worked on at my previous company were all vertical, and that company has now closed down. I have never seen horizontal cryogenic containers before, and I’m still not sure how the inner tank of such containers is secured. Just like in vertical containers, is it secured with steel straps, or are there two internal supports holding the tank in place? What kind of insulating material is used for those supports? Could you provide some information so that we can learn more about this as well?
The vacuum level for vacuuming the low-temperature storage tank must be verified on-site by the inspection agency, with signature required