| 摘要 |
1. Process for cooling of hollow synthetic material profiles during extrusion by means of direct heat exchange with liquid nitrogen, which is introduced via a boring in the mandrel (3) of the extrusion tool into the interior of the hollow synthetic material (6), characterised in that the nitrogen has a pressure of 2 to 8 bar and a temperature below its boiling point, what means that it is subcooled, and that the liquid in the extrusion tool moves through a capillary tube (4) with a maximum inside diameter of 1,2 mm, which capillary tube is enclosed by an insulation tube (5). |
