Centring mandrel for large pipes being worked - has end reinforcement and bolted cages for sprung centring rollers

摘要

The mandrel is inserted in a straight pipe and maintains pipe wall integrity during bending by rolling or pressing etc. The mandrel is of general cylindrical form and expands under internal pressure to conform to and apply stabilizing pressure to internal pipe walls, rollers allowing the mandrel to be rapidly displaced axially inside the pipe. Double or integral tubes provide the inflatable element, with internal reinforcement cables and end closures held by bolted collars and bolts hold end frames locating articulating yokes for the rollers which are moved radially outwards under the effect of springs.