Title:
METHOD FOR CONTINUOUSLY PRODUCING PLASTIC TUBES BY BIAXIAL DRAWING AND A PRODUCTION LINE FOR CARRYING OUT SAID METHOD
Document Type and Number:
WIPO Patent Application WO2004080682
Kind Code:
A3
Abstract:
The invention relates to a method for continuously producing plastic tubes by biaxial drawing consisting in producing a blank (E) by extrusion, heating said blank to a molecular orientation temperature, radially dilating it by the internal pressure of a fluid applied between two axially distant obturator rings (7, 11) and in carrying out a calibration (8) and cooling (9) associated with an axial tension produced on a tube at the output thereof. A pressure opposite to the internal pressure is applied to the blank wall from the outside in at least one area which is exposed to the radial dilatation. Said opposite pressure is selected such that it is lower than the internal pressure, thereby preventing a counteraction to said dilatation and remaining sufficient in order to control the dilatation growth in such a way that it is possible to ensure a substantially constant material thickness on the same circumference.
Inventors:
PREVOTAT BERNARD (FR)
Application Number:
PCT/FR2004/000501
Publication Date:
October 28, 2004
Filing Date:
March 03, 2004
Export Citation:
Assignee:
ALPHACAN SA (FR)
PREVOTAT BERNARD (FR)
PREVOTAT BERNARD (FR)
International Classes:
B29C48/09; B29C48/10; B29C48/32; B29C48/90; B29C48/92; B29C55/26; (IPC1-7): B29C47/90; B29C47/92
Domestic Patent References:
| WO2001072499A1 | 2001-10-04 |
Foreign References:
| US3812230A | 1974-05-21 | |||
| US4818467A | 1989-04-04 | |||
| US4472343A | 1984-09-18 | |||
| US3772118A | 1973-11-13 | |||
| US4189288A | 1980-02-19 | |||
| US4749346A | 1988-06-07 |
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