| 摘要 |
The present invention relates to a cargo tank for an extremely low temperature material carrier, which comprises: a hull shell which forms the exterior of a cargo tank; a membrane first protective wall which is in contact with an extremely low temperature material inside the cargo tank; a first insulating wall which is installed in the external side of the first protective wall; a membrane second protective wall which is installed in the external side of the first insulating wall; and a second insulating wall which is placed in the external side of the second protective wall in order to be fixated to the hull shell. The first insulating wall, the second protective wall, and the second insulating wall are fastened by a bolt, and include a back-up plate which is included on the second insulating wall, is supported by the second insulating wall, and adheres to the external surface of the second protective wall. According to the present invention, even when the first insulating wall, the second protective wall, and the second insulating wall are penetrated by a second bolt, the back-up plate pressurizes the second protective wall in order to be adhered to the first insulating wall. Therefore, the second protective wall and the first insulating wall are firmly fastened in order to prevent leakage from a penetrating part on the first insulating wall, the second protective wall, and the second insulating wall, thereby maintaining airtightness. |
