The liquid nitrogen storage tank stores either samples or liquid nitrogen. There may be no samples but no liquid nitrogen. Therefore, all liquid nitrogen storage tanks that are put into use are at low temperature.
In everyone’s impression, it will freeze if it is below 0 °C. Will the deep low temperature of -196 °C in the liquid nitrogen storage tank freeze?
In fact, normally not!
Although the inside of the liquid nitrogen storage tank forms a low temperature environment due to liquid nitrogen, the low temperature cannot be felt from the outside.
Because it is designed according to the thermal insulation principle of the Dewar vacuum jacket, it is divided into two parts: the outer shell and the inner tank. The inner tank is filled with liquid nitrogen, the middle of the outer shell and the inner tank is evacuated, and the insulation and adsorption materials are filled.
With this layer of vacuum, the low temperature cannot be conducted to the outer wall, and the high temperature of the outer wall will not affect the inner tank.
However, if the abnormal situation, such as the liquid nitrogen storage tank is damaged, or the vacuum port is damaged, it is likely to freeze.
Of course, there is another situation. When filling liquid nitrogen, you will see a small amount of ice near the mouth of the tank. This is a normal phenomenon.
If it persists for a long time and lasts for several hours, it can be determined that the vacuum degree of the liquid nitrogen storage tank is damaged, and contact the manufacturer to solve it.