GB638095A - Improvements in methods of and apparatus for the manufacture of pipes, tubes and thelike - Google Patents

Abstract

638,095. Extruding tubes. BARDEX ENGINEERING Ltd., and DEAN, N. W. Aug. 22, 1947, No. 23366. [Class 87 (ii)] [Also in Group XXVIII] Apparatus for making reinforced tubes or pipes comprises an extrusion chamber through which a helical reinforcement may be fed, a nozzle opening in the front of the chamber, a feed member mounted for rotation relatively to the body of the chamber and adapted to engage the reinforcement and to feed it towards the nozzle, a core member extending from the interior of the chamber into the nozzle opening to form with it an annular extrusion nozzle, and means for delivering a plastic material under pressure into the chamber, the arrangement being such that the material with the reinforcement embedded in it is extruded through the nozzle without substantial relative rotation between the material, the core, and the sides of the nozzle opening. A preformed helical reinforcement is advanced through the rotating feed element 23, Fig. 2, by a worm element 24 fixed to the part 23. The helix is supplied to the tube 23 from the pulley end, and moves without receiving positive rotation, to the nozzle 36 formed by a die 6 and a spindle 35. The worm 24 has an axial bore in which is fitted the reduced end 34 of the spindle, the end being freely rotatable in the bore but retained axially by a collar 38. Thermoplastic or thermosetting material-e.g. polyvinyl chloride, is forced by pressure means 5 down the radial passages 17, 18, Fig. 3 into the annular groove 15, through the radial slots 16 into the extrusion chamber 7. The pressure of the material prevents any small rotary movement of the helix which is extruded from the nozzle 37 embedded in the material. The extruded tube may receive final heat or chemical treatment or be water or air cooled. Tubes or pipes of any desired section and dimension can be made by using a nozzle of appropriate shape. A modification has a rotary extrusion chamber and a fixed feed member fed with a rotating helix from a wire coiling machine.