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What are the changes associated with insufficient vacuum in a cryogenic storage dewar?

2024-01-31 11:18:27

The biggest difference between cryogenic containers and ordinary containers, apart from the structure, is the vacuum;

Representative containers such as “cryogenic Storage Dewar” have double-layered bladders + filled with insulating materials. The space between the inner and outer bladders is partially evacuated to isolate heat from the outer wall, avoid heat conduction, and prevent low-temperature diffusion on the inner wall.

Therefore, the quality of ordinary containers depends on the durability of the material, while the cryogenic storage Dewar depends more on the degree of vacuum and the age of the vacuum. The material process is only part of ensuring vacuum. The reason why we say vacuum life is because the cryogenic Dewar vacuum will weaken after a few years with use. This is a normal phenomenon, and users who know liquid nitrogen tank products know it.

What will happen if the Dewar vacuum degree of cryogenic storage is insufficient?

What changes can intuitively reflect that the vacuum degree of the Dewar container is insufficient?

It mainly depends on the storage time of liquid nitrogen!

Let’s compare the existing liquid nitrogen storage time with the usage time when we just purchased the new tank!

If the comparison result does not change much and gradually decreases after 2 or 3 years, for example, it was originally available for 3 months, but now it is more than two months, and the frequency of opening the lid of the cryogenic storage Dewar has not changed much from before, then it is a normal decline. , the quality is no problem.

But if it drops too much after 2 or 3 years and is not within the scope of the standard, for example, it can only be used for half a month or 1 month after 3 months, there may be a problem with the vacuum degree. The reason may be that there are bumps and dents on the outer wall, causing air leakage, or the storage Dewar container is often loaded with samples and moved long distances, causing the neck tube to become loose and cause air leakage. If necessary, contact the manufacturer to help detect and determine the problem and provide a repair plan.

Vacuum degree is the reason why cryogenic storage Dewar can preserve biological samples for a long time. Insufficient vacuum degree will be directly reflected in the storage time of liquid nitrogen. If the decrease range is normal, you can continue to use it. If it is abnormal, it is recommended to seek help from the manufacturer, and they will give Re-vacuum is still an accurate solution for repairs.

What are the changes associated with insufficient vacuum in a cryogenic storage dewar