HOME > SUPPORT

How to fill the liquid nitrogen storage dewar with liquid nitrogen for the first time?

2024-07-10 09:47:52

Everyone should know that the liquid nitrogen storage dewar manufactured by the manufacturer is an empty tank, and it is also an empty tank when it is delivered to the corresponding user, without liquid nitrogen. Because the transportation of cryogenic liquids such as liquid nitrogen is dangerous, it requires a special transport vehicle to transport it, and it will be rejected by express delivery. Therefore, the first thing to do when receiving a new liquid nitrogen dewar is to fill it with liquid nitrogen!

How do you fill the liquid nitrogen storage dewar with liquid nitrogen for the first time? Is it the same as in daily use?

Of course it is different! One principle must be followed: pre-cool before filling!

The newly arrived liquid nitrogen storage dewar, even if it has been tested for evaporation by the manufacturer, has a little liquid nitrogen inside, and there is a little liquid nitrogen low temperature, and nothing is left after transportation. It is just an aluminum alloy insulation tank at room temperature, and the internal temperature is high compared to liquid nitrogen. At this time, it is not easy to fill it with liquid nitrogen directly, which will cause increased loss of liquid nitrogen and irritate the container material.

The correct way is to first inject 1/3 of liquid nitrogen into the liquid nitrogen dewar, cover it with a neck stopper and observe. When the liquid level is calm and no large amount of white gas comes out and the gas in the neck stopper disappears, you can slowly fill it with liquid nitrogen and put in the sample for use.

Of course, if conditions do not allow and pre-cooling is not possible, you can also go to the gas company to fill it up at once, but you must also observe and wait until the liquid level is calm and the frost on the cover plug disappears before putting in the sample. If you find that the frost on the liquid nitrogen dewar tank continues during the observation process after filling, and the frost layer is getting thicker and thicker, you can also determine that there is a problem with the container vacuum, and directly contact the manufacturer to replace it. This also avoids the troublesome operation of putting in and taking out the sample, which is not conducive to the stable low-temperature storage of the sample.

These are the answers to how to fill the liquid nitrogen storage dewar with liquid nitrogen for the first time. Just operate it according to your own actual situation!

How to fill the liquid nitrogen storage dewar with liquid nitrogen for the first time