1. The first filling is usually to fill a normal temperature low-temperature storage tank (including the low-temperature storage tank which has been used again for a period of time) with low-temperature liquid.

2 before the first filling, check and calibrate the liquid level gauge and pressure gauge, check whether all valves are in the correct open and close state, and whether the pipeline is smooth; open the pressure gauge valve, and make the liquid level gauge in the working state according to the liquid level gauge operation procedure.

3 when the low temperature storage tank is used for high-purity low temperature liquid, it must be blown out and replaced. The method is as follows: use 70 ℃ ~ 80 ℃ dry oil-free air or nitrogen to heat and blow out the contents, blow out time shall not be less than 8 hours, and then replace with product gas; For nitrogen lighter than air, it shall be led in from vent valve V-12 and discharged from liquid inlet and outlet valve V-1 at the bottom. For oxygen or argon heavier than air, it shall be led in from liquid inlet and outlet valve V-1 at the bottom and discharged from vent valve V-12. When the pressure of low-temperature storage tank reaches 0.1-0.2mpa, the replaced gas shall be discharged. Repeat this several times, and the purity of the discharged gas shall be tested to meet the requirements The replacement can be stopped only after replacement; the product gas shall also be blown out for each valve pipeline to meet the purity requirements; after replacement, the positive pressure shall be sealed to prevent the external air from being inhaled. 4. It is not necessary to carry out the above purging and replacement treatment for filling and storing general low temperature liquid.

5 for the first filling, it is recommended to use atmospheric pressure filling, that is, open the vent valve V-12 of the content device before filling, and then close it after the completion of the whole treatment filling. The content device is under atmospheric pressure or low pressure during the filling process, which is convenient for operation; For filling rare or precious low-temperature liquid, the inner cylinder of low-temperature storage tank can be cooled with liquid nitrogen first, then replaced with low-temperature product gas to the specified purity, and then filled with low-temperature liquid. When filling, it can be filled with pressure.