| 摘要 |
PROBLEM TO BE SOLVED: To provide a helium liquefied deep freezer, capable of reducing transport and a replenishing of liquefied nitrogen and efficiently operating, without having to discard the expensive liquefied nitrogen in an atmosphere. SOLUTION: The helium liquefied deep freezer comprises a helium compressor 1 for compressing a helium gas for generating helium gas for liquefaction, a helium cold box 2 containing liquefied nitrogen-helium heat exchangers 10A and 10B for cooling the compressed helium gas for liquefaction, multistage refrigerating heat exchangers 11A to 11E and helium expansion units 12A and 12B for generating a cold, and a liquefied nitrogen supply unit 4 for supplying the liquefied nitrogen to the exchangers 10A and 10B. In the deep freezer, the unit 4 has a nitrogen compressor 5, a nitrogen cold box 6 and a liquid nitrogen storage container 7, and a nitrogen circulating pipelines 15, 16A and 24 are provided between the exchanges 10A and 10B. |
