| 摘要 |
<p>The seal consists of a disc of aluminium foil, its lower surface coated with plastic. This is placed over the neck of the plastic container, together with the sealing tool. This tool has a plate, heated by an electrical resistance, which heat welds the inner plastic surface onto the container rim. Two handles are pulled down and a former descends over the heated plate to push the edges of the foil disc over the screwed neck portion. This former is also heated and seals the inner surface of the disc to the container sides.</p> |
