Liquid nitrogen tanks can generally be divided into liquid nitrogen storage tanks and transport-type liquid nitrogen tanks. The liquid nitrogen storage tank is mainly used for the static storage of indoor liquid nitrogen, and it is not suitable for long-distance transportation under working conditions. In order to meet the transportation conditions, the transport-type liquid nitrogen tank has a special shock-proof design. In addition to static storage, it can also be used for transportation when it is filled with liquid nitrogen, but it should also avoid severe collisions and vibrations.
 
Do be careful when filling liquid nitrogen. For new tanks or tanks in a dry state, they must be filled slowly and pre-cooled so as to prevent damage to the inner tank due to too fast cooling to reduce its service life. When filling liquid nitrogen, do not pour liquid nitrogen on the vacuum exhaust port, so as not to cause the vacuum to drop. The cover plug is made of heat-insulating material, which can not only prevent the evaporation of liquid nitrogen, but also play the role of fixing the lifting cylinder. Therefore, it is necessary to minimize the wear when switching to extend the service life.
 
When the liquid nitrogen tank is in use, the remaining amount of liquid nitrogen must be recorded frequently and the liquid nitrogen must be refilled in time. So when should the liquid nitrogen be refilled? How to measure the remaining amount of liquid nitrogen? Use the probe to measure the depth of the liquid nitrogen to know when it is time to fill it.
 
The measurement method is very simple. Put a thin plastic rod as a probe into the tank for a period of time, take it out and put it in the air, and a box line will appear on the probe, so that the height of the liquid nitrogen can be measured. If the liquid nitrogen is not filled in time, it will be exhausted.
 
Another method is to first determine the critical weight of the liquid nitrogen tank (that is, the weight when it needs to refill with liquid nitrogen), and then weigh it at regular intervals. When its weight is the same as the critical weight, it is time to fill it with liquid nitrogen.