| 摘要 |
An apparatus 17 for continuously forming rings of thermoplastic, shrinkable tubular casings 1 includes an unwinding roller 20, a first pair of pinch rolls 2, a ring-forming tool 3, a second pair of pinch rolls 15 and a winding-up roller 21. The tubular casing 1 is passed from the unwinding roller 20 through the pair of pinch rolls 2 and runs along a running-zone A into the ring-forming tool 3, which includes a spiral 19 and guide rollers 7 and 8 on an outer side 5 and an inner side 6, respectively, of the tubular casing 1 as well as a heater 4 for generating hot air. After covering a running-out zone B, the ring casing 16 leaving the ring-forming tool 3 runs through the second pair of pinch rolls 15, which pinches off the gas blown in at low gauge pressure in the section of the tubular casing 1, or of the ring casing 16, between the first pair of rolls 2 and second pair of rolls 15, with the result that said gas remains only in the section mentioned. The ring casing 16 is laid flat along its center line of the ring by the second pair of pinch rolls 15 and is wound up in this state onto the winding-up roller 21, in order then to be shirred and filled in a further step of the process.
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