| 摘要 |
<p>The invention relates to a method for producing a double-walled thermoplastic pipe with integral pipe bell. The aim of the invention is to provide a method with which such a pipe bell can be produced exactly and completely and with little complication. To this end, the inventive method comprises the following steps: a) extruding a first tube (1) in a molding tunnel (4) that is configured by at least one row of molds (5) that are guided on one track, b) waving the tube (1), in at least one first section, and widening it in a second section to give a pipe bell, c) extruding a second tube (6) into the first tube and pressing it against the wave depressions (8) of the first tube (1), d) impinging, while the first tube (1) is being waved and the second tube (6) is extruded into the first one, the space (A) between the two tubes (1) and (6) with a hyperbaric pressure p1, e) impinging, at a predetermined time before or after widening the first tube (1) to a pipe bell, the space (A) between the tubes (1) and (6) with a substantially constant hyperbaric pressure p2</=p1, or with a variable pressure p2 that does not continuously decrease, f) impinging the second tube (6), during extrusion of the second tube (6) into the first tube (1) that is widened to a pipe bell, from within with a hyperbaric pressure p3 and pressing it against the first tube (1), g) and finally again impinging the space (A) between the two tubes with the pressure p1.</p> |
