Safety is not a trivial matter, the use of containers with pressure to pay attention to, even if the liquid nitrogen Dewar tank, which only works with a little low-pressure liquid nitrogen containers, still have to safety first, today Tianchi to talk about how to use the liquid nitrogen Dewar tank to safely add liquid nitrogen.

1.Make sure the pressure is not close to 0.09MPa

With a pressure threshold of 0.09 MPa, the liquid nitrogen Dewar tank is a standard low pressure vessel.

Although it is low pressure, it can’t be said that there is no danger at all, that’s why Tianchi emphasizes that the safe addition of liquid nitrogen should not let the pressure close to 0.09.

Tested by the manufacturer, at 0.02MPa, a small amount of liquid nitrogen can be output, only intermittent and small; when it reaches 0.05MPa, the liquid nitrogen output is continuous and uninterrupted, slightly greater than 0.05MPa, the liquid nitrogen output speed is faster.

However, you should not blindly seek for speed and increase the pressure to nearly 0.09MPa, which brings danger to yourself and is not good for the liquid nitrogen tank itself.

2.Ensure that the valve “each does its job”

Liquid nitrogen Dewar tank in the case of liquid nitrogen, emptying valve should be closed, booster valve should be open, in and out of the liquid valve to see the pressure gauge value to determine the opening time, when the pressure reaches 0.05MPa should be open state.

3 valves have a wrong state, such as the venting valve has been open, even if the booster valve open pressure can not go up, because the venting valve has been in the pressure relief; but if the inlet and outlet valves the open not open, the pressure in the tank continues to increase without release, and the danger escalates.

So, if you want liquid nitrogen Dewar tanks to be filled safely with liquid nitrogen, both of these conditions have to be met!