Liquid nitrogen container, also known as Dewar bottle, has a very thermal insulation effect, will absorb heat to increase pressure, will not absolutely keep warm, but what is the pressure when it works?

 We know that the critical temperature of nitrogen is - 147 degrees and the critical pressure at the critical temperature is 3.4 MPa. The design temperature of liquid nitrogen tank is - 196 degrees. There are two kinds of conventional design pressure, one is 0.8 MPa, the other is 1.6 MPa. These two kinds of design pressure are based on the application requirements.

 Under pressure, when the temperature reaches - 196 degrees, nitrogen becomes a dark blue liquid, that is, liquid nitrogen, which can be stored under pressure and without pressure. The temperature difference is not big, but the longer the time, the higher the temperature will be and the smaller the density will be.