| 摘要 |
PROBLEM TO BE SOLVED: To provide a general type drainage-inspection manhole being convenient for manufacture and being extremely firm. SOLUTION: The drainage-inspection manhole 32 is constituted while having a manhole section 11 and particularly used for a conduit for waste water and/or storm-water discharge. The manhole section is formed as a duplex pipe 1 with a smooth internal pipe 2 and a corrugated external pipe 3 at that time. The external pipe 3 is deformed so as to has at least one connecting base (7, 7', 7") with an edge web 8. Mutually horizontal openings 13, 14 are notched to the connecting bases (7, 7', 7") and the internal pipe 2, and a connector 17 is inserted into these openings 13, 14.
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