| 摘要 |
<p>Foil seals are applied to the mouths of tubular containers of flexible plastic material, by supporting the container (6) on a hollow mandrel (5) aligned with an orifice plate (13) for punching out the appropriate diameter seal. The seal is punched from stock sheet (11) by a reciprocating punch (12) which is also hollow (12a). Sufficient vacuum is applied to the punch bore (12a) to ensure that the seal is retained on the end of the punch during transfer through and beyond the orifice plate until in contact with the mouth of the container body supported by the mandrel. A greater level of suction is applied to the seal via the bore (5a) of the mandrel, to ensure that the seal is detached from the punch and retained on the container mouth as the punch (12) is withdrawn. Used for applying e.g. thermoplastic coated aluminium foil seals to squeeze tubes of plastics material (opt. metallised), prior to filling, capping and sealing of the base of the tubes (in any convenient order). Vacuum assisted transfer increases the reliability of an automatic sealing process.</p> |
