24/06/2005 - Controller General of Patents, Designs, and Trade Marks

(21) Application No. 2551/DEL/1997 A (22) Date of filing of Application: 09/09/1997
(54) Title of the invention: “METHOD AND APPARATUS FOR THE PROCESSING OF
TUBES MADE OF PLASTIC.”
(51) International Classification 7 : B 29C 47/92
(30) Priority Data :
(31) Document No.: 9611705
(32) Date : 26/09/1996
(33) Name of convention country :
FRANCE
(66) Filed U/s 5(2) : NIL
(61) Patent of addition to application No. : NA
(62) Filed on : NA
(63) Divisional to Application No. :NIL
(64) Filed on : NA
Total No. of Pages: 19
(57) Abstract:
(71) Name of the applicant:
ALPHACAN.
Address of the Applicant:
12/18 Avenue de La Jonchere Elysee 2, F-
78170 La Celle Saint-Cloud, France.
(72) Name of the Inventor:
BERNARD PREVOTAT
JEAN-JACQUES ACKET
Method for the processing of tubes made of plastic, especially PVC, obtained by extrusion, according
to which a tube is brought to a molecular orientation temperature higher than ambient temperature and
is subjected to biaxial stretching by radial expansion and by axial elongation, in order to obtain a biorientation
tube having improved mechanical properties. The tube (T) is cut into elements (4) of
specific length when it has just been extruded and when its temperature is higher than the molecular
orientation temperature, each element constituting a blank (5); each blank (5) is placed in an enclosure
(E) in order to be cooled there by a fluid (F) at a temperature near the molecular orientation
temperature, the dwell time of the blank in the enclosure being longer than the time for producing the
blank by extrusion; and the blank (5) is subsequently extracted from the enclosure (E) in order to
undergo the processing which ensures bi-orientation by radial expansion and axial elongation.
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