| 摘要 |
A packaging machine (1) is adapted to form a web (8) of packaging material into a tube to surround items (3) to be packed, the tube then being sealed and severed between successive items to produce individual packages (5). The tube is formed by sealing one surface of an edge zone of the web to the same surface of the opposite edge zone of the web so that, in the finished package, the sealed zones form a flap extending longitudinally of the package. The machine comprises a machine bed (2) and successive pairs of rollers (18,20,22) located in the machine bed forming successive nips for driving the partly formed packages (25,38) towards a sealing and severing station (23) and for forming the required seal between the edge zones of the web, wherein the edge of at least one of at least one of the pairs of rollers (18;20), located adjacent the partly formed packages, is relieved whereby an air passage is formed within the tube at the point where the tube passes the relevant pair of rollers as it moves towards the sealing and severing station (23). The machine additionally comprises means (32,34) for applying a vacuum to the tube adjacent the point where the edge zones of the web are brought together to form the tube.
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