Plastic and nonmetallic article shaping or treating: processes – Direct application of fluid pressure differential to... – Producing multilayer work or article
Patent
1992-06-29
1995-01-24
Vargot, Mathieu D.
Plastic and nonmetallic article shaping or treating: processes
Direct application of fluid pressure differential to...
Producing multilayer work or article
264 36, 264269, 156287, 156294, B29C 6336, F16L 55165
Patent
active
053840860
DESCRIPTION:
BRIEF SUMMARY
This invention relates to the lining of pipelines or passageways in which a synthetic composition is utilised either as an adhesive or to form in itself a layer which forms a coating on the pipeline or passageway surface. In specific examples, the coating material is a curable synthetic resin, which may be of the ambient cured type or maybe of a type which requires initiation for example by heat or light or other means to commence the cure.
BACKGROUND
Lining processes in which curable synthetic resin is used are known, and typical of such a process is described in British patent specification no. 1449455. As described in that patent specification, a lining process for an underground passageway such as a sewer involves the use of a flexible lining tube which comprises a resin absorbent inner layer such as a fibrous felt, and an impermeable outer layer. To insert the flexible tube into the pipeline or passageway to which the tube is sized, the tube is everted using fluid pressure, typically a head of .water. The resin impregnated fibrous inner layer is therefore turned inside out and is presented to the surface to be lined. When the lining tube has been applied fully, the resin soaking the absorbent layer is cured so that in fact the resin absorbent layer and the cured resin form a rigid lining shell or skin on the passageway surface. The impermeable membrane may serve as a surface to the finished tube, or it may alternatively be removed. This lining process is extremely successful and is used throughout the world and is in fact known as the Insituform (Registered trademark) process. The flexible lining tube comprising the inner fibrous layer and the outer impermeable layer is trademarked by the name Insitutube.
SUMMARY OF THE INVENTION
The present invention has specific application to processes involving the applying of Insitutubes to underground passageway surfaces, but varies in concept from the Insituform method described above.
In its widest aspect, the present invention comprises a method of lining a pipeline or passageway surface wherein a body of fluent synthetic resin is housed in the pipeline or passageway between an everting face of an inwardly travelling lining tube of resin absorbent material which is preimpregnated impregnated with synthetic resin to exclude air therefrom and a backstop means ensuring the creation of a pressure from the body of fluent material against the everting face, so that the everting face the bulk of fluent synthetic resin and the backstop move together along the surface to be lined. It is preferred that the backstop be a "rolling pig" which comprises a tubular member of a flexible material with the ends turned back on themselves and connected together. The pig is inflated and will roll upon itself as the coating proceeds along the passageway.
The everting tube preferably is an Insitutube comprising an inner fibrous absorbent layer and an outer impermeably membrane, in which case the invention has the significant advantage that a void free Insitupipe bonded or bendable to the original surface results. The method may comprise the provision of a launching tee piece located at the end of the pipeline or passageway and into which the body of the fluent composition can be loaded. The everting tube enters the tee from one arm and exits via the other arm directly into the pipeline or passageway moving the body of fluent material into the passageway as it progresses.
This method is particularly suitable for applying thick coatings to, for example, steel pipelines for the purposes of corrosion protection. It is particularly useful for drinking water pipes and will suitably replace the conventional lining method for such pipes which comprises the application of cement mortar. More recently such pipes have been lined by a spray on technique using epoxy resin, a process which has met with some success.
THE DRAWINGS
An embodiment of the present invention is illustrated by way of example only with reference to the accompanying drawings wherein;
FIG. 1 is a sectional side elev
REFERENCES:
patent: 4009063 (1977-02-01), Wood
patent: 4434115 (1984-02-01), Chick
patent: 4602974 (1986-07-01), Wood
patent: 4752511 (1988-06-01), Driver
Insituform (Netherlands) BV
Vargot Mathieu D.
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