A common liquid nitrogen storage device is a nitrogen tank, which is divided into low pressure and high pressure. The pressure of the low pressure tank is below 100 psi, and the pressure of the high pressure tank is above 100 psi. Its volume is generally two kinds of 2000 gallons and 2500 gallons. The structure is divided into inner and outer layers. The inner layer is made of stainless steel, the outer layer is made of forged steel, the inner layer is covered with heat insulation material, and the inner and outer layers are vacuumed to prevent heat exchange. The tank is equipped with a pressure regulating valve, a liquid level gauge, a safety valve, a pressure relief valve, etc.