Shaw Industries, Inc.

Michael A Romano

Robert Edward Steele

Alfredo Andrenacci

John H Oliver

Peter Jackson

Dilip K Tailor

Donald C Warren

An article, for example a pipe, has a first covering such as a polymer layer, and a second covering, such as a repair patch or a repair deposit of melt-on adhesive or a wrap or a sleeve protecting a welded joint between two lengths of such pipe. The second covering may have a functional coating on an underside which is applied on and is at least partially superimposed over the first covering. A cured deposit of thermoset resin is applied at least over the edges of the second covering, for example in the form of a fibrous tape impregnated with a curable resin composition, and bonds to the first and second coverings. The resin deposit provides the second covering with increased stability against displacement laterally of said first covering, for example as a result of soil stress.

Superimposed coverings having increased stability

A pipeline is covered with a continuous wrapping sheet having heat-activatable adhesive on its inner side. The wrapping may be helically applied or may be heat shrunk to impart a circumferential stress conforming the wrapping tightly to the surface of the pipe. High frequency induction heating is applied to cause the adhesive to wet and bond to the pipe surface. The wrapping can be applied progressively and continuously along a pipeline excavated from the ground while the pipeline is in service. The product conveyed within the pipe assists in rapidly cooling the adhesive and wrapping sheet so that the pipe can be promptly relaid in the ground.

Method for covering a pipeline by wrapping

A heat shrinkable wrap-around sleeve comprises a heat shrinkable sheet with a heat stable strip welded on one end. The free end of the heat stable strip is overlapped on the outer side of the opposite end of the sheet and welded thereto by heating applied directly on the outer side. This allows the material of the strip to differ in its properties from the material of the sheet, so that the nature of welded closure can be tailored to particular applications. It also allows manufacture of sleeves having hold-down adhesives applied on them to be conducted with greater ease and economy. The sleeve can be manufactured using continuous welding, for example by heated wedge welding.

Heat shrinkable protective sheets

A longitudinally heat shrinkable closure sheet has a hold-down adhesive portion adjacent each longitudinal end for application on the exposed end portions a heat shrinkable wrap-around sleeve applied around a pipe or other article to be covered. Heat is applied to the closure sheet in order to weld the adhesive free portion of the underside of the closure sheet to the end portions of wrap-around sleeve. The initial shrinkage of the closure sheet between the hold-down adhesive portions draws it tightly into contact with the upper side of the end portions. Shearing forces are applied between the closure sheet and the end portions firstly as the closure sheet contracts relative to the end portions, and secondly, as the sleeve shrinks, develops hoop stress and stretches the closure sheet, and a high strength fusion bond is achieved between the closure sheet and sleeve.

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Hamilton, Canada

Michael A Romano