| 摘要 |
<p>Appts. for packaging items under vacuum between two layers of thermoplastic film has a moving belt to guide a continuous sheet of film loaded at intervals with items which are successively positioned beneath the track of an overhead hood moving at right angles to the supporting film. The support belt is clamped beneath the hood path with rows of holes in the belt alongside the film borders, aligned with holes in the clamp. The hood is retracted laterally to be loaded with a piece of film which can be heated and carried by the hood to a position over the articles to be carried. The hood is lowered to complete a vacuum chamber in which the upper film is first lifted by suction and then pressurised against the carrier film to enclose the article after the gap between the films has been evacuated via the holes in the support belt and its clamping frame. The film faces are then welded to seal the edges of the evacuated pack. Illustrated packaging food portions. The design involves only one transport device (belt) to carry the pack film to, through and from the chamber, compared with e.g., twin conveyors and roll nips or sweeper arms working in unison and sometimes involving pressure on the pack edges.</p> |
