| 摘要 |
PROBLEM TO BE SOLVED: To make a packing material for a tank lid stuck fast with a uniform pressure distribution to the entire circumference of the lid with the number of fastening positions lessened as compared with conventional ways by using an O-ring as the packing material for the tank lid. SOLUTION: The lid structure comprises a tank main body 1 having an opening 6 serving as a manhole at its upside and a double lid 10 composed of an inner lid 11 for closing the opening and an outer lid 12. The inner lid 11 is in a structure wherein the upper end of a circumferential raised side panel 4 rising from the inside plate 13 is curled toward the outside and downside, and the packing material 7 to be stuck fast from the lower opening-side 16 against the upper brim of the opening 6 of the tank main body 1 is fitted into the inside of the curled part 15. The outer lid 12 is put on to the inner lid 11 at the outside of the curled part 15 of the inner lid and fastened to the opening 6 with fastening devices 20 arranged at a plurality of intervals in equal angles in the circumferential direction of the opening. |
