Verfahren zur Herstellung von Kunststoff-Hohlkoerpern, wie Rohren od. dgl

967,411. Producing hollow bodies having one or more internal webs. J. H. DANZER. Sept. 17, 1962 [Dec. 14, 1961], No. 35300/62. Heading B5A. In a method for the production of elongated hollow bodies containing one or more internal webs by extrusion, the outer wall 1 and one or more internal webs 2 joined to the outer wall are extruded simultaneously, the extruded and still plastic material is drawn away from the extruder at a rate faster than that of extrusion so as to elongate it, the elongated material is passed through a suction operated forming device 4 serving to stretch the outer wall and the or each internal web radially, the formed article then being hardened by cooling, and finally passed through a chamber 5 where it is subjected to alpha, and/or beta and/or gamma radiation, and/or to low or high frequency electrical treatment. As the material leaves the extruded nozzle 3 it may be given a uni-directional and/or two-directional twist in the course of elongation. The internal webs 2 may also be extruded at a faster rate than the outer wall 1.