Patent GB-1024307-A (GB)
IPC: B29C53/60
Filed: 1962-10-01
Abstract: 1,024,307. Reinforced plastic pipes. APOLLO CARLON PIPE CO. Oct. 1, 1962 [Oct. 2, 1961], No. 37117/62. Heading F2P.  Apparatus for making tape-reinforced, plastic pipe comprises a longitudinally extending tubular mandrel 376 and conveyer elements 400, each having a portion overlying the outer surface of the mandrel and another portion extending through the mandrel, each conveyer element being movable longitudinally of the mandrel, and a wrapper means on the mandrel in overlying relation with a part at least of the portion of the conveyer elements overlying the outer surface of the mandrel, the wrapper means including a spirally wound wrapper 444b having adjacent convolutions in spaced relation and auxiliary wrapping means 446b bridging the spaces between adjacent convolutions of the wrapper 444b. The mandrel, on the outer surface thereof is provided with a number of longitudinally extending, circumferentially spaced, endless conveyer chains, tapes, ribbons or wires 400, each of which pass between adjacent spacers 388, around a sprocket into the interior of the mandrel. Spirally wound wrapper means overlie the chains 400 to provide a relatively smooth, resin-impervious, tube-forming surface and these comprise a relatively wide wrapper 444b and an auxiliary wrapper 446b which prevents resin from seeping into the mandrel to clog the conveyer elements; alternatively, a tape which is employed instead of the wrapper 446b becomes part of the formed pipe. A stripper and guide finger supported by the tube 396 strips the wrapper 444b from the interior surface of the formed pipe and guides the wrapper by turning it into and on itself to form the spiral within the mandrel and which runs in the opposite direction to the spiral formed by the wrapper portion on the exterior of the mandrel. The auxiliary wrapper 446b follows substantially an identical path to the wrapper 444b and employs similar mechanisms for wrapping it on to the mandrel. A finger secured to the tube 396 strips the auxiliary wrapper from the interior surface of the formed pipe. The pipes are formed on the machine by holically winding one or more plies of plastic impregnated fibreglass tape preferably comprising a multiplicity of strands of substantially parallel glass fibres dispersed throughout a partially cured plastic material, e.g. an epoxy, polyester or a phenolic resin; alternatively, non-impregnated tape is employed and the resin applied thereto. The plies of the tapes may be laid on the mandrel with oppositely directed helices. To ensure that the tapes lie flat in the mandrel and to overcome the inherent stiffness of the tapes the mandrel is electrically heated by wire heater elements laid in longitudinal grooves in the mandrel or in spaces between the adjacent conveyer elements 400. Curing of the resin is accomplished by the use of an electrically-heated oven having an air intake and an air outlet connected to a blower. Prior to curing of the resin, the pipe is provided with a helical outer wrapper, applied under tension, which is stripped from the pipe after the pipe has passed through the oven, to be passed back through the oven. The pipe may pass through a second oven for a postcuring process, the auxiliary wrapper 446b moving with the pipe through the oven and being returned through the pipe to the interior of the mandrel; the wrapper may be of a material to form an integral portion of the pipe.