| 摘要 |
This machine comprises a frame, spacing means arranged in the interior ( 3 ) of the tubular film ( 1 ) to separate the walls, traction means ( 8 ) to draw the tubular film and an inflating and welding device ( 5, 6, 7, 12 ). The inflating and welding means is provided with at least one hollow needle ( 5 ) for inflation, means ( 2, 2 a, and 2 b) to prevent the air escaping toward said reel, that is to say, upstream. Said means ( 2 ) to prevent the escape of air are placed between the means ( 3 ) provided within the said film and the reel. The inflating and welding device ( 5, 6, 7, 12 ) is located after the means ( 3 ) provided within said film and before the traction means ( 8 ) for drawing said tubular film ( 1 ) through the inflating and welding device. The hollow needle ( 5 ) of the inflating and welding device is attached to a first beam ( 12 ) located on one side of the said film and controlled by a first actuator ( 13 ) and two heating elements ( 6 ) located upstream and downstream of the hollow needle attached to a second beam ( 10 ) located on the other side of said film controlled by a second actuator ( 11 ). The means for preventing the air introduced into the tubular film from escaping towards the said reel, that is to say, upstream, comprise an elongate element ( 2 b) extending in a transverse direction relative to the film ( 1 ) attached to said first beam ( 12 ) in such a way as to be held away from said film during the movement of the latter and being introduced into a recess ( 2 a) provided in a plate ( 2 ) on the frame of the machine to force said film into the recess to form a sealed fold in the latter.
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