Views:88 Author:Site Editor Publish Time: 2019-10-29 Origin:Site
In cell culture or other experiments, it is often necessary to preserve cells or tissues in liquid nitrogen for subsequent experiments. The improper use of liquid nitrogen tanks often results in human injury or loss of cell samples. The following points should be noted in the use process.
1. Due to the large heat of the liquid nitrogen container, the heat balance time will be long if it’s the first time to be filled, and it can be pre-cooled (about 60L) with a small amount of liquid nitrogen medium, and then slowly filled, so that it is not easy to form ice jam.
2. In order to reduce the loss of nitrogen, please refill the nitrogen when there is a small amount of liquid nitrogen in the liquid nitrogen tank, or fill the liquid nitrogen within 48 hours after using the liquid nitrogen.
3. In order to ensure the safety and reliability of liquid nitrogen tanks, liquid nitrogen tanks can only be filled with liquid nitrogen, liquid oxygen and liquid argon.
4. When infusion, water and frost on the outer surface of the liquid nitrogen tank is normal. When the pressure increasing valve of the liquid nitrogen tank is opened for boosting operation, since the pressurized coil is attached to the inner wall of the outer tube of the liquid nitrogen tank, heat from the outer tube will be absorbed and vaporized when the liquid nitrogen passes, so there may be spots of frost on the outer tube of the liquid nitrogen tank. After closing the liquid nitrogen tank booster valve, the frost point will slowly dissipate. When the valve is closed and the infusion operation is not performed, the outer surface of the liquid nitrogen tank has water and frost, which indicates that the vacuum of the liquid nitrogen tank has been destroyed, and the liquid nitrogen tank cannot be used any more. We need to look for professional manufacturers of liquid nitrogen tanks for repair.
5. When transporting liquid nitrogen medium on the road below grade 3 or grade 3, the vehicle speed should not exceed 30 km/h.
6. Vacuum nozzle on liquid nitrogen tank, the seal of safety valve and the lead seal can not be damaged.
7. If the liquid nitrogen tank is not used for a long time, please discharge and dry the liquid nitrogen medium inside the liquid nitrogen tank, and then close all valves to seal.
8. Before filling the liquid nitrogen medium, the container liner and all the valves and pipes must be dried before it can be filled with liquid nitrogen medium. Otherwise, the pipeline will be blocked by ice, which will affect the pressure rise and infusion.
9. The liquid nitrogen tank belongs to the instrumentation category. It should be handled lightly. When opening the valves of the liquid nitrogen tank, the force should not be too large. Especially when connecting the metal hose of the liquid nitrogen tank with the joint at the inlet/outlet valve, the joint should not be tightened too tightly with a strong force. It can be sealed with slight tightening in place, so as not to break the nozzle of the liquid nitrogen tank. When twisting, one hand is used to hold the liquid nitrogen tank.
1. Leakage occurs at the valve. This is due to the improper sealing of the pressure nut of the valve. Tighten it with a wrench.
2. Ice jam phenomenon occurs at the booster coil, and sometimes also at the drain pipe. This is because the moisture in the air enters the container, and it condenses at low temperature, blocking the pipeline. The solution is to first fill the container with nitrogen gas from the nitrogen bottle, raise the pressure inside the container to 0.05MPa-0.09MPa, and empty the liquid medium inside the container. Then use hot nitrogen or dry hot air to the blocked pipe, the ice will be blown and discharged. Finally, close all valves.
These are the precautions and troubleshooting methods for liquid nitrogen tanks. I hope it will raise your safety awareness and prevent problems when using liquid nitrogen tanks.