| 摘要 |
The apparatus comprises a pair of parallel conveyors (T1, T1') with vertical motorized axes (101, 101'), formed by any flexible heat-resistant and air-permeable structure, the inside run of which contacts with appropriate pressure the sides, containing the folded-down flaps to be sealed, of the packaging (P), which is supported from beneath by for example an optional horizontal motorized conveyor (T) travelling in the same direction and at the same speed as the said inside runs of the said lateral conveyors arranged longitudinally behind which are tubular electrical resistors (6, 6') heatable by the joule effect and of low thermal inertia, that dispense jets of hot air through the active inside runs of these conveyors and that are incident upon the flaps of the packagings, in order to produce weld lines thereon. Subsequent means (10, 10') are provided to maintain an appropriate pressure and to cool the said weld lines, before the packagings leave the said apparatus.
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