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US 4,720,211 AGranted
Apparatus for replacing mains
AssigneeBritish Gas Corporation
InventorsRoy Streatfield, Francis D. Wilson
Life of this patent
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AssigneeBritish Gas Corporation
InventorsRoy Streatfield, Francis D. Wilson
Estimating the term…
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.
Apparatus for fracturing and expanding buried fracturable pipe of a crackable fracturable material and positioning a replacement pipe with its centerline substantially coincident with said buried fracturable pipe, comprising:
A device for replacing an existing main of a crackable, fracturable material with a tubular replacement assembly, the device comprising a mole for insertion into and movement along the existing main, the mole having a front portion provided with a fracturing means for applying an intense local pressure against the existing main to crack and fracture it into irregular fragments, said fracturing means comprising at least one blade for engaging against the internal wall to cause the wall to crack and fracture into a plurality of irregular fragments, expansion means for forcing the fragments radially outwardly from the axis of the existing main, generally about said axis, said fracturing means being operable to cause at least some outward movement of the fragments under the action of said intense local pressure which causes the fracturing of the main into irregular fragments, a rear portion provided with means for securing the assembly to the mole, said expansion means comprising a body portion intermediate the front and rear portions to provide a bore for movement of the assembly through the main after fracture and means for driving the mole percussively through the existing main so that the mole is caused to move along the existing main to tow the assembly along the existing main.
A device for replacing an existing buried fracturable main of a crackable, fracturable material with a tubular replacement assembly, the device comprising an elongated main fracturing and bore widening mole for insertion into and movement along the existing main, the mole having a rearwardly, outwardly tapering portion to provide both mains fracturing and bore widening, the portion having a fracturing means for applying an intense local pressure against the existing main to crack and fracture it into irregular fragments, said fracturing means comprising at least one main fracturing member mounted on the tapering portion to engage against and fracture the buried main on movement of the mole through the main to crack and fracture the buried main into a plurality of irregular fragments, said fracturing means being operable to cause at least some outward movement of the fragments under the action of said intense local pressure which causes the fracturing of the main into irregular fragments, the portion also having a small front extremity not greater than the internal diameter of the buried fracturable main and a large extremity greater than the internal diameter of the main, said large extremity comprising an expansion means for forcing the fragments radially outwardly from the axis of the existing main, generally about said axis to provide bore widening of the fractured main, means for connecting the trailing end of the mole to the leading end of the tubular replacement assembly, whereby in use the assembly is moved linearly through the passage so formed, and means for moving the mole through the buried fracturable main.
Apparatus for fracturing and widening the bore of a buried fracturable main of a crackable, fracturable material and positioning a tubular replacement assembly within said buried fracturable main, comprising:
Apparatus for replacing an existing main of a crackable fracturable material with a tubular replacement assembly, the apparatus comprising an elongated mole for insertion into and movement along the existing main, the mole having a fracturing means for applying an intense local pressure against the existing main to crack and fracture it into irregular fragments, said mole comprising a front portion forming a leading end for insertion into the existing main, the front portion being provided with said fracturing means in the form of a plurality of blades which are mounted on the mole for retractable outward movement to engage against and crack and fracture the internal wall of the existing main into a plurality of irregular fragments, said fracturing means being operable to cause at least some outward movement of the fragments under the action of said intense local pressure which causes the fracturing of the main into irregular fragments, said mole further comprising a rear portion provided with means for securing the assembly to the mole, a generally frusto-conical body portion intermediate the front and rear portions, the body portions having adjacent the front portion a smaller external diameter than the internal diameter of the existing main and rearwardly thereof a larger external diameter than the internal diameter of the existing main, said larger external diameter comprising expansion means for moving the fragments outwardly, generally about the axis of the main, for widening out of the bore of the existing main after fracture, and means engagable with the mole for moving the mole along the existing main.
A device for replacing an existing buried fracturable main of a crackable, fracturable material with a tubular replacement assembly, the device comprising an elongated main fracturing and bore widening mole for insertion into and movement along the existing main, the mole having a rearwardly, outwardly tapering bore widening portion having a small extremity not greater than the internal diameter of the buried fracturable main and a large extremity greater than the internal diameter of the buried fracturable main, to provide bore widening, and the mole being provided with a fracturing means for applying an intense local pressure against the existing main to crack and fracture it into irregular fragments, said fracturing means comprising at least one retractable outwardly movable main fracturing member which is so positioned on the mole to engage the internal wall of the fracturable main to crack and fracture the buried fracturable main to debris in the form of a plurality of irregular fragments and causing at least some outward movement of said fragments, said large extremity comprising an expansion means for forcing the fragments radially outwardly from the axis of the existing main, generally about said axis to form a passage, means for connecting the training end of the mole to the leading end of the assembly, whereby in use the new main or liner is moved linearly through the passage so formed, and means for moving the mole through the buried fracturable main.
A device for replacing an existing main of a crackable, fracturable material with a tubular replacement assembly, the device comprising a mole for insertion into and movement along the existing main, the mole having a front portion provided with a fracturing means for applying an intense local pressure against the existing main to crack and fracture it into irregular fragments, said fracturing means comprising at least one projection for engaging the internal wall of the existing main and for causing the wall to crack and fracture into a plurality of irregular fragments, said fracturing means being operable to cause at least some outward movement of the fragments under the action of said intense local pressure which causes the fracturing of the main into irregular fragments, a rear portion provided with means for securing the assembly to the mole, said mole comprising an expansion means for forcing the fragments outwardly, generally about the axis of the main, to provide a bore for movement of the assembly through the main after fracture of the existing main and means for driving the mole through the existing main so that the mole is caused to move along the existing main to tow the assembly along the existing main.
An apparatus for replacing an existing main which is of a rigid material which cracks and is fracturable into irregular fragments, said apparatus comprising;
Dependencies are inferred from the claim text.