| 摘要 |
<p>A thermoplastic film bag, closed at one end, is shrunk round articles which are wrapped with the film and exposed to a jet of hot gas until the film lies tightly round them. The bag is evacuated from its open end before heat-shrinking. The apparatus comprises a cross-beam (3) holding inclined arms (4,5) and vertical columns (6,7) which can be moved in the direction shown to fit the articles (10) to be wrapped. A film bag (11) is placed round the articles (10) with its open end (14) at the bottom on a plate (12) which itself is supported by blocks (15) on a table (18). Before the bag is positioned, the space beneath it is evacuated, drawing air in the side directions (23,24). The bag (11) is then rested with its bottom edges (14) hanging loosely over the base of the plate (12). Air is sucked out through a pipe (20). The film is drawn on to the articles (10). Wrap holds its position partic. beneath the packed articles and ensures a good seal, shrinkage produces uniformly distributed stress in the film.</p> |
