Drainage and inspection manholes for liquid conduits and manhole parts therefor

摘要

Corrugated outer pipe (3) is formed to provide at least one connection socket (7, 7', 7'') with a connection socket ring (8), concentric with the central axis (10), surrounding the opening (13) in the outer pipe, and mounting the connection stubs (17). Preferably the connection socket has an annular flange (16) bounding the opening in the outer pipe.