| 摘要 |
PCT No. PCT/FR91/00407 Sec. 371 Date Nov. 6, 1992 Sec. 102(e) Date Nov. 6, 1992 PCT Filed May 21, 1991 PCT Pub. No. WO91/18180 PCT Pub. Date Nov. 28, 1991.According to the invention, the tubular preform is radially deformable between a longitudinally folded state and substantially cylindrical unfolded state to form a length of rigid tube in situ. The preform comprises a flexible and watertight inner envelope (6) whose peripheral extent is equal to the internal extent of the length of tube, and, formed on the outside of said inner envelope, reinforcement (2) made of filamentary structure comprising a plurality of fibers impregnated with a settable resin, including fibers (3) oriented mainly in the peripheral direction of the preform, each of these fibers (3) extending over more than one turn and co-operating with adjacent fibers by making contact therewith such that adjacent fibers can slide over one another while the preform is in any state other than its unfolded state where, under internal pressure, the fibers are locked together by the friction between them due to a capstan effect.
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