| 摘要 |
PROBLEM TO BE SOLVED: To provide a structure of a protector in installing an underground tank wherein foreign matters can be prevented from entering the protector. SOLUTION: An upper opening 16a of a protector 16 which surrounds a manhole section 13 at an upper end of an underground tank 12 is closed by a protector outer lid 18 and a protector inner lid 19 so that it can be opened/ closed. A gap 22a is provided between an outer peripheral surface of the protector 16 and an inner peripheral surface at a lower end of a manhole 22. Outer diameters of the lids 19, 18 are formed to be smaller than those of a manhole inner lid 25 and a manhole outer lid 24, respectively. In addition, the upper opening 16a of the protector 16 is reduced in diameter.
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