| 摘要 |
A method and apparatus of production of tubes comprising, on an extruder, extruding molten plastics through die formations of a die head so as to extrude tubes each including at least one internal longitudinal web, and subsequently cooling the extruded tubes. In addition, when advancing molten plastics through a die hole (110) of the die head, the die head includes a die mandrel (122) having a first portion (124) attached to the die body and a second portion (126) extending in the die hole (110) so as to extrude the tube with at least one internal longitudinal web, the advancing including conveying molten plastics along a flow passageway (134) in the first portion (124) of the die mandrel (122) towards a central longitudinal region of the die hole at the second portion (126). The die body advantageously has a die mandrel locating device (118) arranged at the upstream side of the die body for locating the die mandrel (122) centrally of the die hole (110) of the die body. Cooling is performed by having a fluid delivering device (202) for directing cooling fluid directly on to a downstream surface of the die head to cool the extruded tubes exiting from the die formations, which are then chopped to the desired size.
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