Liquid nitrogen storage tanks used to store liquid nitrogen frozen samples are usually equipped with neck plugs!
Containers may be of different sizes and calibers may be large or small, but the neck plug always matches its caliber, perfectly fits the can mouth design, and leaves a gap for air to diffuse. It can be said that the liquid nitrogen storage tank may not have a lock cover or a bucket, but the neck plug will not be missing.
The neck plug is made of polyurethane, which is resistant to low temperature and heat preservation. It is used to fix the bucket, and it is an important accessory to prevent external heat from entering the container and increase the volatilization of liquid nitrogen. It also has the function of dust prevention. What if there is no neck plug?
The answer is: yes!
As said before: the neck plug prevents external heat from entering the liquid nitrogen container, and it also prevents dust!
If the neck plug is not covered, the neck of the liquid nitrogen storage tank is empty and faces the air directly. Heat and humid air will inevitably enter the tank. Although the water molecules entering the tank cannot be seen from the outside (because it is a transparent liquid like liquid nitrogen), but When water molecules are added, the bacteria and impurities contained in it will also enter, and the purity of liquid nitrogen will of course decrease.
The same is true for impurities, because the neck is not covered, and objects placed near the liquid nitrogen storage tank may enter the liquid nitrogen tank if they fall. The bacteria on the object also enters, and the purity of the liquid nitrogen is naturally reduced.