| 摘要 |
PROBLEM TO BE SOLVED: To provide a cold keeping unit in which the cold keeping time can be prolonged sufficiently without significantly increasing the overall weight of the unit. SOLUTION: The cold keeping unit comprises a plurality of sheets of thermal insulator 8-1,..., 8-6 disposed in contact with, respectively, with a plurality of heat shield plates 1-1,..., 1-6. With regard to the heat shield plate 1-3, the heat shield plate 1-4 adjacent to the heat shield plate 1-3 and remote from an object 4 to be cooled, and the heat shield plate 1-2 adjacent to the heat shield plate 1-3 and close to the object 4 to be cooled, the ratio of the number of sheets Ni-1 of thermal insulators touching the heat shield plate 1-3 to the number of sheets Ni of thermal insulators touching the heat shield plate 1-2 is reversely proportional to the ratio of the temperature difference (Ti-1 -Ti ) between the heat shield plates 1-4 and 1-3 to the temperature difference (Ti -Ti+1 ) between the heat shield plates 1-3 and 1-2. |
