Like all Liquid nitrogen biological containers, the liquid nitrogen cryogenic freezer also has an inner and outer dual-gallery structure. The two chambers are evacuated and filled with insulating and adsorbent materials to achieve external heat insulation and internal heat preservation. The difference is that other liquid nitrogen containers store samples in the liquid phase, immersing the samples in liquid nitrogen, but the liquid nitrogen freezer stores the samples in the vapor phase, using nitrogen to preserve the samples.
Only nitrogen is needed to maintain a low-temperature environment to preserve stem cells, blood, embryos and other samples?
KGSQ’s answer is: No!
In addition to nitrogen, there is also liquid nitrogen in the liquid nitrogen cryogenic freezer!
It is designed to separate liquid nitrogen and samples. The nitrogen comes from internal liquid nitrogen, not external nitrogen as everyone thinks.
In the inner tank of the liquid nitrogen cryogenic freezer, there is a large tray that separates two spaces. The upper tray is the sample storage area, and the lower tray is prepared for liquid nitrogen and can accommodate 55-320 liters of liquid nitrogen. The bottom of the liquid nitrogen is an evaporator, which evaporates the liquid nitrogen according to the temperature of the sample area and turns it into nitrogen gas, which enters the sample storage area to ensure a low ambient temperature in the upper part.
Therefore, strictly speaking, in the liquid nitrogen cryogenic freezer, only the sample storage area is filled with nitrogen. The entire liquid nitrogen freezer actually contains both liquid nitrogen and nitrogen, and only existing liquid nitrogen can contain nitrogen!