Back to results
US 5,078,546 AGranted
Pipe bursting and replacement method
AssigneeConsolidated Edison Company of New York, Inc.
InventorsAllan T. Fisk, David I. Freed, Thomas A. Mann
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeConsolidated Edison Company of New York, Inc.
InventorsAllan T. Fisk, David I. Freed, Thomas A. Mann
Estimating the term…
Tool for slitting and laterally expanding underground steel gas mains and inserting replacement plastic piping into the spread apart pipeline has a forward end cylindrical portion mounting a single, rearwardly angled blade to make only one line of cut, and a conical pipe spreader portion at its rearward end. The conical spreader portion is eccentrically disposed with respect to the forward end cylindrical portion. A single roller type pipe slitter aligned with the fixed blade may be mounted on a removable extension of the forward end cylindrical portion, to initially groove and weaken the pipe along the intended line of cut. A pneumatically operated impact ram is attached to the rearward end of the tool, as is the leading end of the replacement piping. A wire cable pulls the tool through the underground pipe, thereby grooving, slitting and laterally expanding the pipe. The spacing of the roller slitter in advance of the fixed knife blade is dimensionally related to the length of any coupling or clamp as may be anticipated along the line of cut, and the spacing distance of the fixed knife blade forwardly of the conical spreader portion is related to the cone angle of the latter to increase hoop tension immediately in front of the fixed blade as the cutting proceeds.
A method for bursting a length of underground steel pipe comprising the steps of slitting through the wall thickness of said pipe in the longitudinal direction of said pipe along only one line of cut and progressively spreading said slit pipe wall laterally along said one line of cut, said spreading being performed eccentrically with respect to the longitudinal axis of said pipe length in the direction therefrom towards said one line of cut using a generally conical-shaped spreader having an apex end received within said slit pipe and a base end which is larger than the diameter of said pipe, while maintaining a conical-surface surface-generating element of said spreader in longitudinal adjacent relation to the interior surface of said pipe on the side thereof opposite to said one line of cut.
A method for bursting a length of underground steel pipe and inserting plastic piping therein, said pipe having external pipe coupling or clamping means attached thereto at at least one underground location therealong, comprising the steps of pulling a pipe bursting tool from its forward end through said pipe length to slit said pipe and each of said pipe coupling or clamping means along only one line of cut therethrough and to laterally spread said slit pipe along its length, said lateral spreading being progressively induced by an eccentrically disposed conical-shaped spreader portion of said pipe bursting tool, and augmenting said pulling using repeated hammering on the rearward end of said pipe bursting tool at least during its movement past each of said pipe coupling or clamping means, said pipe being slit using a fixed knife blade projecting angularly outwardly and rearwardly from said bursting tool and a rotary pipe grooving tool longitudinally aligned with said knife blade and projecting outwardly from said bursting tool at a location spaced forwardly away from said knife blade.
A method for bursting a length of steel pipe comprising slitting through the wall thickness of said pipe in the longitudinal direction of said pipe along only one line of cut by moving a fixed slitting blade along said one line of cut while inducing localized hoop tension progressively within said pipe on said line of cut immediately in advance of said slitting blade as it moves therealong using a generally conical-shaped spreader having an apex end received within said slit pipe and a base end which is larger than the diameter of said pipe, while maintaining conical-surface a surface-generating element of said spreader in longitudinal adjacent relation to the interior surface of said pipe on the side thereof opposite to said one line of cut.
A method for bursting a length of underground steel pipe comprising the steps of grooving the inner wall surface of said pipe length longitudinally along only one line, and inducing localized hoop tension within the pipe wall progressively on and along said grooved line to split and spread the pipe wall laterally apart, said localized hoop tension being progressively induced by laterally spreading the pipe wall eccentrically with respect to the longitudinal axis of said pipe length in the direction therefrom towards said one grooved line using a generally conical-shaped spreader having an apex end received within said grooved pipe and a base end which is larger than the diameter of said pipe, while maintaining a conical-surface surface-generating element of said spreader in longitudinal adjacent relation to the interior surface element of said pipe on the side thereof opposite to said one line.
Dependencies are inferred from the claim text.