A customer consulted this question. The purchased liquid nitrogen tank was frequently used for a long period of time. It was not used to protect the neck stopper of the liquid nitrogen tank, resulting in damage to the container's neck plug.
In this case, you can't replace it with other size plugs, or use a thing that has been tattered to wrap things around and fix them.
Sealed stoppers must not be used to prevent liquid nitrogen from evaporating continuously, and the resulting nitrogen pressure increases causing damage to the container.
Related reading:Accessory of Liquid Nitrogen Container