Apparatus, methods, and liners for repairing conduits

Abstract

A method of repairing an intersection of a first conduit and a second conduit that includes the steps of providing a repair material configured to conform to an intersection of a first conduit and a second conduit and impregnating the repair material with a heat curable resin. The method further includes positioning the repair material at the intersection of the conduits and compressing the repair material against said intersection with a structure having a plurality of electrically conductive fibers. Electric current is applied to the conductive fibers to resistively heat the fibers to facilitate curing of the resin in the repair material.

Description

RELATED CASES [0001] This application is a divisional application of pending application Ser. No. 10 / 182,889 filed Apr. 28, 2003 and which is incorporated by reference herein. Application Ser. No. 10 / 182,889 is a U.S. National filing under §371 of International Application No. PCT / US01 / 03498 filed 2 Feb. 2001 and claiming priority to U.S. Ser. No. 60 / 179,687 filed Feb. 2, 2000, U.S. Ser. No. 60 / 179,806 filed Feb. 2, 2000, and Ser. No. 60 / 179,686 filed Feb. 2, 2000.TECHNICAL FIELD [0002] The present invention generally relates to an apparatus and method for the installation of a repair material within a conduit or pipe such as a sanitary sewer line. More specifically, the invention pertains to an apparatus and method for the installation of a repair material at the intersecting junction between two transversely opposed pipes or conduits. [0003] The present invention also relates to a method and apparatus for repair of large diameter sanitary sewer pipe or conduit. Specifically, the i...

AI Technical Summary

Benefits of technology

[0031] The interface or intersection sealing apparatus of the present invention allows for a structural, pre-impregnated, flanged composite repair collar to be efficiently positioned and cured in place. The cured composite provides the restoration of the connection between a main line conduit and an intersecting line. The apparatus is equipped with an inflation heating device, which is capable of inverting the repair material into the lateral line, and an articulated, heated caul plate that firmly compresses the flanged portion of the material within the mainline. The integral heating system comprises two differentially controlled heating assemblies containing an array of electrically conductive fiber heating elements embedded in both constructions to generate heat for cure. The device further provides a launching platform to safely transport and position the repair material and house the electro-pneumatic and electrical components for the separate operation of the inflatable components and the mechanical motion components. The repair materials used are all pre-impregnated off-site in a controlled environment, heat activated and stable at ambient temperatures therefore eliminating premature cross-linking of the resin matrix before the repair is satisfactorily positioned, and ensuring thorough and consistent resin wet-out. Because of the localized concentration of applied heat, cure cycles can be as fast as 15 minutes, depending on resin systems used, without disturbing surrounding areas.

[0032] According to an object of another embodiment of the invention, a liner is provided for repairing damage in large diameter conduits. The liner comprises a plurality of discrete heating zones and a plurality of interface areas. Each heating zone is impregnated with a heat curable resin. Each zone has a fiber architecture formed from the combination of a plurality of conductive fibers and non-conductive fibers. Preferably, the conductive fibers are carbon fibers, which also give the fiber architecture high strength qualities.

Problems solved by technology

The cause of leakage can vary from improper installation to environmental conditions to normal aging or the detrimental effects of the substances transported on the pipe materials.

Regardless of the cause, leakage is undesirable.

In conditions where the intersecting angles of the main pipe and the lateral pipe constitute an obtuse angle, as typically encountered in a convention sewer “wyes”, a needle-punched felt material does not possess the necessary flexibility to conform well to the surrounding pipe walls.

Even after much effort and expense has been expended on the remediation of these systems, the areas of confluence between the main lines and intersecting side lines (hereinafter called laterals) has only minimally been addressed.

This has resulted in many failures due to premature curing of the resin, inadequate resin cross-linking and shrinkage.

In addition, because the resin is applied to the repair material at the installation site, inconsistencies in both resin content and mixing procedures can be expected.

The shortcomings of these types of systems lay in the difficulty of the prescribed radiant light source to penetrate through the thickness of the repair material and the overall fragility of such devices.

Another problem is encountered with repairing pipes having large diameters.

If the ambient temperature is too low, which is common with underground conduits, the resin will not completely cure and the liner can collapse.

In contrast, if the ambient temperature is too high, the resin can cure prematurely, that is before the liner is properly located in the damaged portion of the conduit.

There are a number of disadvantages to curing a liner with hot water or steam.

First, the equipment required to heat the water or to create steam is extremely expensive and inefficient.

Second, curing with either fluid requires a temperature ramp-up, which consumes long periods of time.

Curing a liner with hot water, steam, or ambient is also negatively affected by heat sink in the conduit.

In addition, heat sink can prevent the complete curing of all resin in the liner, thereby reducing the strength and durability of the liner.

These factors reduce both the cost efficiency and process efficiency of hot water, steam, and ambient cure.

The conventional liners used to repair large diameter conduits are very thick and generally require a large amount of resin.

The large amount of resin exacerbates the need for ramped temperatures and as a result, further increases curing times while reducing the efficiency of the repair.

Due to their large size and weight, liners for large diameter conduits are difficult to handle and maneuver within the damaged conduit.

Also, liners for large diameter conduits are more susceptible to the negative effects of the heat sink.

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