Does the gas-phase liquid nitrogen tank add nitrogen?

We know that gas-phase liquid nitrogen tanks are named after gas storage! Compared with ordinary liquid nitrogen tank, it relies on nitrogen to preserve biological samples. Users who don't know much will ask: does the gas-phase liquid nitrogen tank add nitrogen?

Of course not! Add liquid nitrogen.

Nitrogen here refers to the gas produced by evaporation of liquid nitrogen. Therefore, although the gas-phase liquid nitrogen tank is a sample stored directly with gas, it actually needs the support of liquid nitrogen.

One more question. Since the sample is stored by nitrogen generated by evaporation of liquid nitrogen, why not directly fill the tank with nitrogen?

Because liquid nitrogen will vaporize when it meets hot gas, and nitrogen will quickly drift away at room temperature, it is too expensive to transport nitrogen directly into the tank. The gas-phase liquid nitrogen tank adopts "liquid phase separation" mode, that is, liquid nitrogen and the sample are in the same container, but separated by a tray, and the evaporated gas just enters the sample area to realize low-temperature storage.

To sum up, liquid nitrogen is still added to the gas-phase liquid nitrogen tank instead of nitrogen.