Improvements in or relating to the manufacture of tubes and hoses from thermoplasticmaterial

摘要

954,700. Seaming non-metallic sheet material. J. FERENCZI. Sept. 12, 1960 [Oct. 13, 1959], No. 31356/60. Heading B5K. A method of manufacturing tubes or hoses of polyethylene comprises forming a tube by the blowing method, flattening the tube so that two foils of material overlie each other, stressing the tube, and prior to winding the tube, splitting it longitudinally by moving it longitudinally past a stationary heated cutting-tool which is heated to a temperature sufficiently high above the fusion temperature of the polyethylene to cause the superimposed cut edges of the tube walls to be welded together along their length. As illustrated, a tube made of foil layers 3, 31 lying upon each other pass between guide drums 1 and 2 in the direction of arrow 10. A cutting tool 4 secured to heating head 5 heated by electric heater 51 and controlled by thermo-element 6 serves to split the foils 3, 31 and at the same time to weld the cut edges together. The angle aαof the cutting edge 7 to the plane of the foils is preferably less than 60 degrees and the cutting tool is of increased thickness beyond the cutting edge so as to prevent the cut edges coming together again.