| 摘要 |
1375471 Welding apparatus for a packaging machine ALPURA-KORECO AG 10 July 1972 [9 July 1971] 32254/72 Heading B8C In a packaging machine 14 which includes means, e.g. rings 15, 15, arranged to form an elongate web 16 of packaging material into tubular shape whose external surface has a discontinuity in the region of the edges 16a, 16b of the web, and welding apparatus arranged to weld together the edges 16a, 16b of the formed web to produce a tube for subsequent conversion into finished packages, the welding apparatus has a heating zone in which there is a hood 21 arranged to define, with parts of the external surface of the formed web on either side of the discontinuity, a heating chamber, means 20 being provided to supply hot gas to the hood, and pressure-applying means 42, 45 being arranged to press together those edge positions of the web which have been heated in the heating zone. The hood is adapted to the cylindrical shape of the tube 16 to direct a portion of the supply of hot air between the two edges 16a, 16b and the remainder on to the exterior wall surfaces adjacent the edges 16a, 16b so that, as well as heating these exterior wall surfaces, the hot air prevents the circulation thereon of colder surrounding air. Air, forced by a fan 17 over a heater 18 and a sterile filter 19, is supplied, at a temperature of 140‹ C., to the hood 21. In an alternative arrangement, Figs. 3, 4, the hood 21 is sub-divided by partitions 32, 33 to form a first chamber 35 which opens, in a nozzle-like manner towards the gap between the edges 16a, 16b and which, with the respective adjacent wall portions 36, 37 of the hood, form additional side chambers 38, 39. The latter communicate with the first chamber 35 through openings 40, 41 respectively in the partitions 32, 33 to pass hot air, at a reduced speed, to the exterior surfaces of the tube adjacent the edges 16b, 16a. The interior welding roller 42 is mounted on a lever 34 which is pivoted to the filling tube 22 and which is spring-loaded, at 44, towards the cooperating fixed exterior welding wheel 5. The web 11 comprises paper coated on one side with plastics. |
