| 摘要 |
PROBLEM TO BE SOLVED: To effectively ensure a cold air retaining property in a cold air retaining chamber. SOLUTION: As a basic structure in the cold air retaining chamber 3, a cold air outlet part having a cold air outlet port and a circulating cold air inlet port is provided. On the floor of the cold air retaining chamber 3, longitudinally extending cargo supporters are arranged with a horizontal space disposed between them to form a cold air circulating passage between the horizontally adjacent cargo supporters. Cold air discharged from the cold air outlet port of the cold air outlet is circulated along the ceiling, the back wall, the cold air circulating passage and the front wall of the cold air retaining chamber and sucked from the circulating cold air inlet port. As a characteristic structure, the cargo supporter has a hollow part and gas of low thermal conductivity and/or a heat insulating material is sealed in the hollow part. As means for providing a heat insulating property in the cargo supporter, the hollow part may be made substantially vacuum or the cargo supporter may be made of a material of low thermal conductivity. |
