| 摘要 |
Manhole for sewage pipe systems, is formed by rotation molding with joints shaped to give different mounting zones for fitting to at least one nominal interior diameter of the pipe fitting The manhole, for a sewage channel system, is shaped by rotation molding with at least one joint to be mounted at the fitting at one end of the sewage pipe. The joint has at least one mounting zone (111-113), each zone being of dimensions to fit the diameter of the fitting in at least three successive sections. The first sections (21,24,27), nearest the center of the manhole, are at a conicity of 0-5% angled towards the joint axis and away from the manhole. The intermediate sections (22,25,28) have an outer surface in a truncated cone shape with a conicity of /-10%. The third sections (23,26,29), furthest from the center, have a conicity of 0-5% angled towards the joint axis and away from the manhole. The structure gives an effective mounting, despite the inherent spacing at the side with a rotation molding.
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