| 摘要 |
PURPOSE:To obtain a repeatedly usable fluorocarbon-free vacuum heat insulating box body wherein the space between outer and inner boxes is packed with a foamed heat insulating materials by degassing open-cell hard polyurethane foam used as the foamed heat insulating material under vacuum. CONSTITUTION:A main body 1 of a heat insulating box body is constituted by packing the space between an outer box 2 made of a metal and an inner box 3 made of plastic with a foamed heat insulating material 4. In this case, open-cell hard polyurethane foam is used as the foamed heat insulating material 4. Further, the vacuum indicator 5 communicating with the foamed heat insulating material 4 and an opening and closing valve 6 are arranged to the box main body 1 through a pipe 7 and a vacuum pump is connected to the opening and closing valve 6. By degassing the foamed heat insulating material 4 under vacuum, a vacuum heat insulating box body is obtained. By again performing vacuum degassing if necessary, initial heat insulating capacity is restored to again easily utilize the heat insulating box body. |
