Wells – Processes – Perforating – weakening – bending or separating pipe at an...
Patent
1983-11-29
1987-03-10
Novosad, Stephen J.
Wells
Processes
Perforating, weakening, bending or separating pipe at an...
166 557, 409143, E21B 2906
Patent
active
046484540
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a robot for operation inside a pipe or bore-hole, and to a method of cutting an aperture in the wall of the pipe. The invention is primarily applicable to the renovation of sewers and the accurate cutting of apertures for service inlets in an internal repair pipe or lining fitted inside an existing sewer pipe.
The age of a large proportion of drainage sewers in the established industrial countries is such that leaks and collapses are becoming increasingly common, to the extent that there is a need for improved techniques whereby existing underground sewers can be renovated quickly, effectively, and with the minimum amount of excavation work. Known renovation techniques include lining an existing earthenware sewer pipe with a plastics, generally polyethylene, inner pipe which is slid into the existing pipe section by section from an excavated shaft until the inner pipe emerges at another excavated shaft which may be several hundred meters distant. This is known as slip lining. In a second known method, a flexible plastics tube with an open end and a closed end is fitted at its open end to the open end of the existing pipe, and the closed end of the flexible pipe is then passed through the open end so that the flexible pipe is effectively folded inside out. The closed end is pushed along the sewer by water pressure until it has reached its maximum extent, and then the material of the inner pipe is cured or hardened by pumping hot water into the pipe to yield a hard plastics lining moulded to the interior wall of the original sewer pipe. This is known as `in-situ` lining.
A problem with both techniques arises at service pipe locations where an apperture has to be cut in the lining pipe at each service inlet so that each inlet is connected to the interior of the renovated sewer. Known methods of cutting the wall of the lining from inside the lining using currently available remotely controlled machines or robots tend to result in inlet apertures which do not correspond accurately in position or shape to the inlet pipe, and which have rough edges with unwanted projections liable to impair drainage efficiency. In addition, the known machines are not readily adaptable to different pipe sizes or to irregularities in the shape and position of service inlet openings.
According to this invention there is provided a remotely controllable travelling robot for operation inside a pipe or bore-hole, comprising: a carriage for engaging the wall of the pipe or bore-hole, a support structure mounted on the carriage, and a tool mounting assembly carried by the support structure and rotatable relative to the support structure by remote control about a longitudinal axis, wherein the support structure is movable by remote control relative to the carriage to vary the position of the said longitudinal axis of rotation relative to the carriage.
The dimensions of the robot are such that it can be drawn through, for example, a sewer pipe which has been lined in one of the methods described above. Preferably, the tool mounting assembly includes a tool mounting head and drive means, the drive means being remotely controllable for pivoting the tool mounting head about a transverse axis.
For cutting an aperture in a pipe lining at a branch pipe location, a compressed air driven motor is mounted on the tool mounting head and fitted with a cutting tool having cutting surfaces directed laterally away from the motor axis so that once the lining has been punctured, the robot can be used to inch the drill around the circumference of the branch pipe opening, cutting away the lining material in registry with the edge of the branch pipe opening, using the branch pipe interior surface as a template. A preferred cutting tool in accordance with the invention has a smooth enlarged distal end portion to minimise damage to the branch pipe interior surface.
Lateral movements of the tool in the aperture are controlled by rotation of the tool housing assembly in the support structure, whilst longitudinal movements, i.e. longitudi
REFERENCES:
patent: 2942092 (1960-06-01), Cammann
patent: 3507340 (1970-04-01), Voetter
patent: 4197908 (1980-09-01), Davis et al.
patent: 4442891 (1984-04-01), Wood
Byrne John J.
Kile Bradford E.
Neuder William P.
Novosad Stephen J.
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