| 摘要 |
This invention relates to an apparatus for manufacturing ribbed pipes. The central axis of the apparatus has a core (8, 9, 10) about which a material in a plastic state is extruded through a nozzle (11). The end of the core has a kernel (10) of a substantially constant diameter which calibrates the inner surface of the pipe. The outer surface of the pipe acquires its form from axially moving moulds (1, 2). The kernel has a heated initial zone and a cooled end zone (14, 15). In known apparatus, the grooves (13) of the moulds are often incompletely filled and the inner surface of the pipe is made uneven. These drawbacks can be avoided by disposing a cooled widening end face (20) at the outset of the end zone (15) of the kernel. |
