04720211 is referenced by 39 patents and cites 13 patents.

An apparatus for replacing an existing buried pipe of a crackable, fracturable material. The apparatus has a fracturing structure which applies an intense local pressure to crack and fracture the existing buried pipe into irregular fragments. This fracturing structure can include one or a plurality of blades, some of which may be retractably and expandably movable. The structure which exerts the intense local pressure is also operable to effect at least some outward movement of the fragments. An expansion structure moves the fragments radially outwardly, generally about the axis of the existing main, to provide a passage for a replacement tubular assembly. The apparatus is moveable through the existing main by the action of either a pushing or a pulling force, and the pushing force may be applied by percussive action.

Title
Apparatus for replacing mains
Application Number
326138
Publication Number
4720211
Application Date
August 4, 1986
Publication Date
January 19, 1988
Inventor
Francis D Wilson
Blackburn
GB
Roy Streatfield
Bilsborrow, Nr. Preston
GB
Agent
Larson and Taylor
Assignee
British Gas Corporation
GB
IPC
F16L 1/00
F16L 55/18
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