| 摘要 |
In a vacuum packaging machine there is provided the combination of a sealing unit and vacuum unit. The sealing unit comprises first and second sealing dies and the vacuum unit comprises a primary spacer located adjacent the input end of the sealing dies. The primary spacer is spaced from the first die to form a first web feeding passage therebetween and is spaced from the second die to form a second web feeding passage therebetween. The vacuum unit also includes a secondary spacer located adjacent the input end of the dies and mounted for movement between a retracted position permitting closure of the dies to effect sealing and an extended position maintaining at least a portion of the webs which passed through the first and second web feeding passages, in a spaced relationship to permit evacuation of the container space formed between the webs. A drive mechanism is provided for driving the secondary spacer to and fro between the retracted and extended positions and vacuum passages are provided in the vacuum drawing unit opening towards the sealing dies for communicating with the interior of a packaging space when the secondary spacers are in the extended position to maintain the webs in a spaced relationship whereby atmosphere from the container space may be withdrawn through the vacuum passage means prior to sealing of the webs.
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