Pipes and tubular conduits – Repairing – Patches
Reexamination Certificate
1998-05-01
2001-01-09
Hook, James (Department: 3752)
Pipes and tubular conduits
Repairing
Patches
C138S097000, C156S287000, C264S267000, C405S150100
Reexamination Certificate
active
06170531
ABSTRACT:
The invention relates to a flexible tubular lining material, especially a flexible tubular lining material for conduits and/or pipelines (hereinafter abbreviated as pipelines) in need of rehabilitation, a method for the production of a pipe lining, a pipe lining produced from the lining material as well as the use of the lining material for their production.
BACKGROUND OF THE INVENTION
In the rehabilitation of covered laid conduits and pipelines, especially house conduits with small pipe diameter, for example in walls or underground, rehabilitation by removal and exchange of the defective partial section is an extensive and cost intensive measure. The excavation and work to free the pipes associated with this are time and cost intensive, are frequently difficult to perform and require particular measures to protect against dirt, especially with work carried out in buildings. Additionally, construction sites resulting from this represent a potential source of danger and a inconvenience to the surroundings. For this reason, there exists a great need for alternative constructional methods which allow for a lining of pipelines without having to expose the pipelines thereby and, if need be, without having to remove and exchange the pipeline portions.
To date, various non-invasive methods for pipe lining are known as well as various materials which are used for this purpose.
To improve damage at points in impassable pipelines, resin-impregnated laminate sleeves are used which consist of glass cloth impregnated with a cold-hardening resin for example. The glass fiber mats impregnated with resin and cut to the desired dimension are provided with separation foil and wrapped around a packer that is capable of being introduced into the pipe which is then inserted into the pipe. This device is positioned at the damaged spot and pressurized such that the resin-impregnated glass cloth is pressed closely against the pipe and cures there. After curing of the resin, the introducing device is removed again from the pipe and a resin/glass fiber composite sleeve remains in the pipeline.
A system is known for lining longer pipe sections which consists of a polyester, needled felt flexible tube, a two-component epoxy with which the felt tube is impregnated and a silicone calibrating tube. The calibrating tube in pre-determined length is inserted into the needled felt tube and closed at the end. After impregnation of the needled felt tube with epoxy, the system is inserted into the pipeline by means of a cable winch. Then, the calibrating tube is pressurized with air whereby the impregnated felt tube is pressed closely against the pipeline. After curing of the resin, the pressure is released and the calibrating tube is removed, and a felt/resin composite pipe remains in the pipeline.
This system is primarily suitable for lining of house connection pipelines in which both pipe ends are well accessible. It is not useable for pipelines which do not allow the tubular system to be pulled through, and, additionally, it requires a very circumspect method of working because the epoxy resin is applied on the outside of the needled felt tube. Furthermore, the system is not suitable for crease-free rehabilitation of pipelines with bends of more than 670.
In a different method, a system is employed which consists of a woven tube with a glass/felt/glass sandwich construction which is impregnated with a light-curing UP resin, a highly flexible inner foil and an outer foil which is impermeable to styrene and UV. This system (liner) is pre-fabricated in the factory in accordance to the diameter and length of the pipeline to be lined and inserted in the pipeline from existing shafts. Then, a further foil is pressed into the pipe by means of air pressure in an inversion method whereby the inserted liner is pressed against the pipe wall. The resin/ woven tube system pressed in this manner is irradiated and cured with UV light from previously mounted packers equipped with UV lamps.
This system is also not suited for pipes with sharply angled bends of 90° for example. Furthermore, the possibility must also exist here to pull the resin-impregnated woven tube through by means of a winch and the removal of the inner foil after curing of the resin requires an additional work step.
Additionally, the lining materials described above have the disadvantage that they have a seam in the lengthwise direction along which the originally flat material is bound to a flexible tubular form. This seam represents a potential point of fracture at which a detachment of the lining can begin and which can lead to the formation of creases.
A flexible tubular lining material for pipelines which can contain bends and curved sections is disclosed in DE 35 05 107. This lining material consists of a flexible tubular knitted or woven textile jacket that is coated with an air-impermeable coating of a flexible synthetic resin. For lining a pipe, this lining material is introduced into the pipe under applied pressure in an inversion method such that the textile side comes to lie against the inner wall of the pipe and the synthetic resin coating forms the most inward layer of the lined pipe. The textile layer is adhesively bonded with the outlying pipe with a binder previously introduced in the lining material.
The textile jacket is a compact, non-compressible woven fabric or knitted fabric of curly polybutylene terephthalate fibers (warp thread) and other synthetic fibers (weft thread). The textile jacket as well as the synthetic resin used for its coating is biaxially stretchable whereby adaptation of the lining material to the form of the pipeline occurs, especially in bends and curved sections, with application of pressure to the lining material introduced into the pipe. Formation of creases should be avoided thereby.
However, intensive experimental studies of the inventor have resulted in the fact that a lining of complicated pipe sections, such as bends of 900 for example, cannot be obtained in a satisfactory, crease-free manner with a lining material of a biaxially stretchable textile jacket which is coated with a flexible synthetic resin. Rather, a composite of this type leads to the formation of creases in the inner bend in the region of sharp bends such as 90° and/or to detachment of the lining material from the inner wall of the pipe in the outer bend. Hence, this problem could not be satisfactorily solved.
As a consequence, the object of the invention is to develop a lining material which is suitable for crease-free lining of pipelines in need of rehabilitation that have a complicated structure, especially bends of up to 90°, changes in the pipe inner diameter along the pipeline to be lined or complex portions with complicated geometry in the region of branched connections.
Furthermore, a method is provided that makes the production of a pipe lining possible in an easy, clean and cost effective manner.
DETAILED DESCRIPTION
In direct connection with this, a further object of the present invention is to provide a pipe lining which has excellent sealing properties and load-bearing capacity and fits closely to the lined pipe in all regions without separating from this and without forming creases.
SUMMARY OF THE INVENTION
The above objects are solved according to the invention by providing a lining material comprising a plush textile tube and a foil tube as defined in claim
1
as well as by providing the pipe lining as it is defined in claim
24
and the method for its production as defined in claim
14
.
A new lining material as well as a new pipe lining particularly for the field of public as well as private pipeline rehabilitation can be provided by this surprising manufacturing technology solution which not only represents a subtle distinction over the state of the art but which also considerably furthers this by the following advantages:
providing a lining material which fits closely and can also be installed crease-free in complicated pipeline systems.
production of a pipe which is completely seam-free and joint-free from the basement to
Bunschi Hans
Jung Harald
Scheib Heinz
Fitch Even Tabin & Flannery
Hook James
Karl Otto Braun KG
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