Precautions for Self-pressurized Liquid Nitrogen Tank Use
Self-pressurized liquid nitrogen tanks are pressurized, so you must be careful when using them, which are different from atmospheric liquid nitrogen tanks. The self-pressurized liquid nitrogen tank is mainly used for transportation, storage, transfer and supplement of liquid medium (liquid nitrogen, liquid oxygen, liquid argon), and can also be used as a cold source for other refrigeration devices. The container is composed of an inner tank, an outer shell and an instrument valve. There is a pressure gauge on the upper part, which can easily observe the pressure of the inner tank. Two safety valves are equipped to improve the safety of the container.
When using self-pressurized liquid nitrogen tanks, do pay attention to the following items:
1. Due to the high heat of the container, the thermal equilibrium time is longer when filling the liquid for the first time. Therefore, it can be filled with a small amount of liquid medium for pre-cooling, and then filled slowly, so that it is not easy to form an ice block.
2. In order to reduce the loss during filling in the future, please refill the container when there is still a small amount of liquid in the container. Or fill it within 48 hours after using up the liquid.
3. To ensure the safety and reliability of the container in use, only liquid nitrogen, liquid oxygen, and liquid argon can be filled.
4. Water and frost on the outer surface of the container during infusion are normal. When the booster valve is opened for boosting work, since the booster coil is attached to the inner wall of the outer cylinder, the heat of the outer cylinder will be absorbed and vaporized when the liquid passes through the coil to achieve the purpose of boosting pressure. There may be speckled frost on the outer cylinder. After closing the booster valve, the frost spots will slowly dissipate. When the pressure-increasing valve is closed and no infusion is being performed, there is water and frost on the outer surface of the container, which indicates that the vacuum of the container has been destroyed and it can no longer be used. At this time, you should find a professional manufacturer for repair or scrapping.
5. When transporting liquid media on roads of class III or below, the speed of the car should not exceed 30km/h.
6. The vacuum nozzle on the container, the seal of the safety valve, and the lead seal cannot be damaged.
7. If the container is not used for a long time, please drain the liquid medium inside the container and blow dry, then close all valves and seal it.
8. Before the container is filled with liquid medium, dry air must be used to dry the container and all valves and pipes before the liquid medium can be filled, otherwise it will cause the pipeline to freeze and block (ice block), which will affect the pressure increase and infusion .
9. This equipment belongs to the instrument and meter category. It should be handled with care when using it. When opening the valves, the force should be moderate, not too high, and the speed should not be too fast, especially the connection between the metal hose and the inlet/discharge valve. When connecting, do not over-tighten it with strong force, just slightly tighten it in place to seal it (the ball head structure is easy to seal), so as not to twist the nozzle or even break it. Hold the valve body with one hand when screwing.