GB484567A - Improvements relating to the production of flexible tubes and pipes - Google Patents

Abstract

<PICT:0484567/III/1> A flexible tube comprises a preformed tubular former provided with a layer of a vinyl resin, e.g. polyvinyl alcohol and its derivatives, on its inner and/or outer surfaces. The former is preferably a braided or woven tube of metal, paper or textile threads, but it may be a rubber or flexible metal tube. The application of the coating resin may be effected by dipping. Fig. 1 shows a plurality of formers 1 arranged vertically between two frames 2, 3 and above a dipping well 10 containing the resin. The frame 2 is suspended from an overhead conveyer 5 which is mounted on a rail 11 and is provided with lifting and lowering mechanism A. The arrangement is such that the formers may be lowered into the well 10 and then transferred by the conveyer 5 to a drying chamber or oven, and, if desired, again returned to the dipping well for one or more additional immersions. The formers may be wetted prior to the coating operation by immersion in a well containing water &c. and, if necessary, the wells may be provided with heating jackets 12. The frames 2, 3 may be formed as shown in Fig. 7, the frame 2 comprising a disc 28 with apertures 29 locating bored plugs 36 to which the upper ends of the formers are attached, and the frame 3, which is connected to the frame 2 by a central <PICT:0484567/III/2> <PICT:0484567/III/3> <PICT:0484567/III/4> rod 31, consisting of a network of plates 32 formed with bushes 33 into which the lower ends of the formers are clamped by plugs 34, the latter being provided with central bores 35 when it is desired to coat the formers both internally and externally. Fig. 16 shows an arrangement for internally coating a single former. The former 1 is suspended over a nozzle 52 to which coating resin is supplied by a pump 53, excess resin being permitted to return to the supply tank 54 after a predetermined time by a cock 56 and spout 76; an outer coating may also be applied to the former by permitting the resin to overflow at the upper end of said former. In a modification, Fig. 17, a former is located between nozzles 57, 58 within a chamber 59 to which coating resin is supplied and then p withdrawn. A tube formed as above may be reinforced by one or more braided covers coated externally with resin, or provided with a final coating of paint, a lapping of tape, or a woven, braided or rubber covering.