| 摘要 |
The injection moulding plant (1) used for the plastic covering tube has an injection head (2) comprising a central coil-shaped unit (4) fitted in a channel (3). This unit is centered in the channel by vanes or spokes (5). Molten plastic (6) is fed to the head, and is past the vanes. At the head outlet a tubular jet (9) of plastic is produced and then cooled (10), from the outlet (11) of which the prepared plastic tube (12) emerges. Polyethane or polyvinylchloride may be used. The coil-shaped unit has a channel coaxially arranged within it, into which a cable (14) is fed coinciding with plastic tube prodn. Feed into the channel is via a tube (15) which protects the cable against the head emanating from the molten plastic. The tube may have coils for coolant. Cable is fed from a magazine (16) activated by a synchronisation unit (17) which is controlled by a plastic tube feed-out speed monitor (18). |
