Connection of a pipe to a precast concrete ring manhole - by expanding flexible junction tube to seal in hole in manhole wall

摘要

The process for connecting a drainage pipe into a precast concrete ring manhole, entails placing a flexible junction tube with peripheral tolerance in a hole fashioned in the manhole wall, subjecting this junction to a radial expansion until it bears hermetically on the hole periphery, maintaining it in this position via internal clamping, and finally clamping it onto the pipe exterior. The hole in the manhole wall is drilled, and of greater diameter than the pipe, and centred on a reference point which lies on the longitudinal axis of the incoming pipe. Pref. the pipe extends into the wall opening, and radial expansion of the junction is effected by expanding an internal clamping collar against its inner walls. The collar is expanded radially by an hydraulic unit exerting pressures of at least 70 kg/cm2.