| 摘要 |
PURPOSE: To remove air and prevent freezing at an outlet port owing to moisture in air by supplying purge gas in a space in the neighborhood region of the outlet port side part which is further from a liquid gas chamber. CONSTITUTION: A nozzle 13 is provided standing straight in a main chamber 6 on the bottom wall 11 of a liquid nitrogen container 2, and an outlet port 12 which is facing downward and is always open is provided in the same. In the inside of the nozzle 13, a cylindrical piston 16, and a ring shape wall part 14 for forming a cylinder 15 are provided, and a plurality of flow ports 18 are provided going through. A sub-chamber 17 always communicating with the outlet port 12 is formed between the cylinder 15 and the piston 16, and by the work of the piston, liquid nitrogen flows in and out. At the lower side of the container 2, a shroud having a passage 27 for the liquid nitrogen dispensed from the sub-chamber 17 is mounted, the end face 28 forms a region 29 apart from the nozzle 13, the end face 28 is provided with a passage 30 for introducing nitrogen gas from another supply source and the air in the region 29 is removed by the nitrogen gas. The nitrogen gas pressure prevents the liquid nitrogen in the sub-chamber from leaking. |
