Patent GB-1291108-A (GB)
Title: Improvements in jacketing systems for insulated pipelines
Inventor: TERKEL MIKE
IPC: F16L59/10
Filed: 1969-12-24
Abstract: 1291108 Insulated pipes L C ABBOTT (M Terkel S M Rose & F R Smylie) 24 Dec 1969 62791/69 Heading F2P A jacketing system for an insulated pipeline comprises a number of identical initially openwrap jacket sections 10, each jacket section comprising an elongated jacket portion proper 12 and a relatively short extension portion 20 at one end of the jacket portion, there being along one of the longitudinal edges of the jacket section means 14 for receiving and thereupon securing it to the opposite longitudinal edge (16, Fig. 1, not shown) this means extending along the length of the jacket portion proper only and terminating at the extension portion 20 which has instead at this edge a circumferentially extending tab 22 which overlies the opposing edge of the extension portion upon full closure of the jacket section being effected. In a preferred embodiment the jackets 10 comprise a sheet of lightweight metal, e.g. aluminium, which is internally faced with a specially treated kraft paper facing which serves as a moisture barrier between the aluminium and the pipeline insulation. A Z-lock 14 is formed along one longitudinal edge of the jacket by bending the edge of the sheet back and under on itself (14a, Fig. 4, not shown) and then bending the bent-under portion forwardly and again under on itself (14b) to define a longitudinally running open mouth (14m) positioned to receive the opposite longitudinal plain edge (16) of the sheet so that the said Z-lock 14 functions as a friction-type lock seam which holds the meeting edges of the jacket closed. The Z-lock 14 does not continue into the extension portion 20 which instead carries a circumferentially extending tab (22, Fig. 1, not shown) which extends a substantial distance over the opposite edge portion 16a when jacket edge portion 16 is held by said lock 14. The extension portion 20 overlaps the jacket portion of the preceding jacket, the overlap being limited by the abutment of the Z-lock portions of the two jackets. A clip 28 is applied to secure overlapping tab (22) to the other edge (16a) of extension portion 20. The clip is formed by bending a flat sheet of metal so that the upper arm 32, is shorter than the lower arm (30, Fig. 2, not shown). The clip may be opened for application to the jacket by insertion of, e.g. a screwdriver blade into slot 40. The leading edge (32a) of arm (32) is cut to the same angle as edge (22b, Fig. 1, not shown) of tab (22), and carries a downwardly inclined tongue 32t which grips tap (22). Means for permanent attachment are provided by sets of aligned holes 36a, (36b) and 38a, (38b) (Fig. 5, not shown). Insertion of a punching tool into the upper holes produces dimples (44a and 44b, Fig. 5, not shown) in both sides of extension portion 20, and forces them into the tower holes, thus fastening them together, and also produces dimples in the overlapped jacket portion of the preceding jacket 10R, thus securing the two jacket portions together.  In a second embodiment the tongue and slot of the clip are replaced by a crescent-shaped notch (56, Fig. 7, not shown). After application of the clip the edge portions of the tab (22) and the underlying extension portion (16a) exposed by notch (56) are turned up by insertion of a suitable tool to form a bight-end locking key (58, Fig. 10, not shown).