Abstract: A conductive polymeric tape has elongate electrodes, (6) extending along its long edges, and comprises a central longitudinal strip (8) of different resistance to the remainder of the tape. The strip (8) extends part way only along the tape. The tape may also, or instead, contain discontinuities (20) preferably extending across the tape. The purpose of the strip (8) and the discontinuities (20) is to control the passage of electrical current and also the heat output of different parts of the tape.

Abstract: The invention relates to heat-recoverable covers which comprise embedded electrical resistance heaters, and to methods of covering an elongate object using such covers. In a preferred embodiment (FIG. 5), the cover comprises a heat-recoverable polymeric sheet (22) or fabric, provided with upstanding rails (24,25) as a first closure means. A heating element (36) is embedded in the sheet and arranged to follow a serpentine path such that each return loop portion 38 projects beyond the edges of the cover. The sheet is coated on its inner surface with a layer of adhesive and/or sealant (28,30). In use, the cover is wrapped around a substrate (32) at least once, and first and second closure means (24,25and 26,27) are engaged to hold the cover in the wrapped configuration. The cover is then heated to cause the cover to recover, and the adhesive and/or sealant to form a seal.

Abstract: The invention relates to a heat-recoverable covers which comprises embedded electrical resistance heaters, and to methods of covering an elongate object using such covers.In a preferred embodiment, the cover comprises a heat-recoverable polymeric sheet (22) or fabric, provided with upstanding rails (24,25) as a first closure means. A heating element (36) is embedded in the sheet, and arranged to follow a serpentine path such that each return loop portion 38 projects beyond the edges of the cover. The sheet is coated on its inner surface with a layer of adhesive and/or sealant (28,30).In use, the cover is wrapped around a substrate (32) at least once, and first and second closure means (24,25 and 26,27) are engaged to hold the cover in the wrapped configuration. The cover is then heated to cause the cover to recover, and the adhesive and/or sealant to form a seal.

Abstract: The assembly comprises a wraparound heat recoverable sleeve, and a resilient girdle provided with means for fastening opposed edge regions thereof together, thereby enabling the girdle to hold the sleeve in its wrapped configuration during recovery.The girdle is particularly suitable for use with sleeves that are wrapped around an object more than once.

Abstract: A heat-recoverable article for bonding to an object, particularly for sealing a joint between pre-insulated pipes, consists of a layer of heat-recoverable polymeric material, a layer of a bonding material which preferably is heat-activatable, and a laminar metal heating element which has a plurality of apertures through its thickness to permit the element to be deformed in the plane thereof by a change in the shape of the apertures, and which is inbuilt either in one of or between the said layers. The recoverable material is arranged so that when it is heated by the element, it can recover and deform the element as aforesaid, in use to force the layer of bonding material against the object.

Abstract: A heat-recoverable article for sealing or insulating the surface of a substrate comprises a dimensionally heat-recoverable member and heat expansible material positioned in the direction of recovery thereof so that when heat is applied the material expands and is urged towards the surface by the recoverable member. The recoverable member may be made from a plastics material or a metal alloy possessing memory properties but is preferably made from a resiliently recoverable member held in a deformed state by fusible retaining means, which in some cases may be made from the heat expansible material itself. Especially preferred are longitudinally split tubular heat-recoverable members in which the fusible retaining means comprises a hot melt adhesive positioned between the overlapping edges.