| 摘要 |
814,016. Extruding plastic tubes. COMPAGNIE FRANCAISE DES METAUX. July 13, 1956 [July 21, 1955, April 13, 1956], No. 21815/56. Class 87(2). An extruded tube of plastic material, e.g. a polyamide or polythene, is passed through a cooling passage having holes therein which allow cooling liquid to contact the tube. As shown in Fig. 1, an extruded tube 3 is passed through a helix of copper, polyamide or polytetrafluoroethylene wire 20 of circular, rectangular or oval cross-section mounted in a cylinder 24 through which cooling liquid is circulated. In a modification (see Fig. 6, not shown) the cylinder 24 may be split up into compartments to allow different pressures and temperatures to be applied to different parts of the tube. The pressures may be less than atmospheric, to cause the tube to be forced into contact with the cylinder. The passage may also be formed by a perforated tube or a series of metal plates 50, Fig. 9, held together by bolts 54 and having a central aperture 51 for the passage of the tube. In a further modification, Fig. 11, four sets of plates 50 arranged parallel to the direction of travel of the tube form the passage. |
