Hydraulic and earth engineering – Underground passageway – e.g. – tunnel – Lining
Patent
1994-10-19
1998-03-10
Taylor, Dennis L.
Hydraulic and earth engineering
Underground passageway, e.g., tunnel
Lining
405146, 4051501, 405154, 405156, F16L 5516, F16L 100
Patent
active
057253285
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The invention relates to a system and a process for relining transportation pipelines, such as sewerage pipelines or pipe sections.
Relining is a process for restoring damaged, generally underground transportation lines by introduction of a new internal pipeline conduit or the like into the damaged existing line.
BACKGROUND ART
In a known relining process, a long pipeline conduit of pipes of plastic, for example of polyethylene, welded together is pushed into the damaged sewer section. Since the pipes are not very flexible, relatively large excavations are required for this.
In the case of so-called short pipe relining, short pipes of plastic of about 0.5 to not more than 1 m in length are fitted into standard existing manholes and pushed or drawn from this existing manhole into the sewer section to be restored (DE-A 34 13 294).
Because of the large number of pipe connections, these pipes are as a rule not reliably impervious to exfiltration and, in the case of adjacent ground water (entry of water from outside) to infiltration. Furthermore, the relatively rigid pipes of plastic can be employed only if the damaged sewer section has a largely constant internal diameter.
It has already been proposed (DE-A 27 04 438) to restore sewerage pipes by inserting a flexible pipeline inside the discharge pipe, the external diameter of the flexible pipeline being smaller than the internal diameter of the discharge pipe and the flexible pipeline being positioned with a distance from the discharge pipe to form an annular space. In this process, this annular space is filled with a hardenable filling composition of low viscosity, magnesium cement, for example, being used as the filling composition. An essential disadvantage of this process is that centering of the inliner with respect to the pipe to be restored cannot be achieved or can be achieved only with great effort. In the case of water pressure acting externally, there is furthermore the risk of denting of the new pipeline.
To avoid these disadvantages, DE-A1 39 30 984 proposes a process in which a lining tube (inliner) of flexible PVC is used which has, on its outside, a thick-threaded layer of random fiber of polyamide as a spacer. A fast-hardening mortar (so-called dammer) is introduced into the annular space kept free between the sewerage pipe to be restored and the actual inliner by the layer of random fiber and is hardened. A similar process is proposed in DE-A1 39 34 980, HDPE (high density polyethylene) also being proposed as the material for the inliner.
However, flexible PVC has a deficient resistance to chemicals for many application purposes. Finally, the production tion of this two-layered inliner (actual inliner and layer of random fiber) is expensive and is practically impossible in the case of many material combinations.
A process for relining waste water sewers in which a continuous rigid HDPE pipe is folded during manufacture to a U-shaped cross-section, with severe heating, and this deformed cross-section is fixed with tapes is disclosed in the "reprint from bbr 5/90; U-Liners; Protokoll einer Sanierung, Imbema Rohrsanierungs GmbH". This structure, which is still quite rigid, is then drawn into the sewer and heated with steam under increased pressure (about 1.3 bar) to the thermoplastic state, the HDPE pipe assuming its original circular cross-section again. This process is characterized by a high expenditure and a high consumption of energy.
Finally, a nubbed sealing web for relining waste water pipes is disclosed in DE-U 90 12 003, WO 91/10862 and the company brochure "Steuler 1989". However, this rigid inliner of HDPE can be used only for subsequent restoration of walk-in sewerage pipes of relatively large diameter.
DE-C 23 62 784 discloses a system in which a non-woven tube coated with plastic on one side is impregnated with resin and hardener beforehand such that, after introduction by the inversion process into the pipeline to be restored and after pressing against the pipe wall by means of water pressure, it hardens as a
REFERENCES:
patent: 4770562 (1988-09-01), Muller et al.
patent: 5145281 (1992-09-01), Molyneux
patent: 5190705 (1993-03-01), Corazza
patent: 5427154 (1995-06-01), Stephens
HT Troplast AG
Taylor Dennis L.
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