| 摘要 |
Disclosed is a device for producing double-walled corrugated pipes (72) with an extrusion nozzle 12) and a cooling mandrel (14) protruding into a molding channel (16) formed by corrugator molding jaws (18, 20). The extrusion nozzle (12) comprises a first annular nozzle opening (34) for producing an outer shell (62) and a second annular nozzle opening (40) for producing an inner shell (64). The outer shell (62) produced by the first annular opening (34) is suctioned in the molding channel (16) with the aid of vacuum so that it is pressed against the corrugated cross-ribbed inner surface (66) of the corrugator molding jaws (18, 20). In order to prevent low pressure from acting upon the inner shell, i.e. to prevent a difference in pressure between the inside and outside of the inner shell (64) upon exit from the second annual ring opening (4), the extraction nozzle (12) is provided with at least one first and at least one second ventilation hole (74) and (76) which are connected to the surrounding area of the device.
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