Flexible pipe for transporting fluid and associated method
This flexible fluid transport pipe includes an inner polymer sheath defining a fluid circulation passage with a central axis; at least one armor layer positioned outside the inner sheath; an inner carcass, positioned in the inner sheath, the inner carcass comprising a first bent tape defining a helical interstice emerging toward the central axis. The pipe includes a helical insert with a T-shaped cross-section comprising a rod inserted in the helical interstice and two wings protruding on either side of the rod to inwardly close off the helical interstice. The helical insert is formed from a second bent tape.
1. A method for producing a flexible pipe, comprising:
forming an inner carcass, the inner carcass comprising a first bent tape defining a helical interstice emerging toward a first central axis;
producing an inner polymer sheath defining a fluid circulation path with the first central axis, the inner carcass being positioned in the inner sheath;
arranging at least one layer of outer armors outside the inner sheath;
placing a helical insert with a T-shaped cross-section in the helical interstice, the helical insert comprising a rod, inserted in the helical interstice, and two wings protruding on either side of the rod to inwardly close off the helical interstice,
wherein the helical insert is formed by bending a second tape; and
bending a first flank against a second flank, the first flank and the second flank defining between them an intermediate space to form at least one of the rod and at least one wing of the two wings.
2. The method according to claim 1 , further including passing the second tape in an insert profiler to form an insert profile with a T-shaped cross-section, winding the insert profile around a mandrel, and passing the first tape in a carcass profiler to form a carcass profile and winding the carcass profile around the insert profile on the mandrel.
3. The method according to claim 2 , wherein the insert profiler and the carcass profiler are positioned on either side of the mandrel, the insert profile being brought onto the mandrel opposite the carcass profile.
4. The method according to claim 2 , further including closing the carcass profile after its winding around the insert profile.
5. The method according to claim 2 , wherein passing the second tape in the insert profiler includes bending the second tape along a second central axis to form the rod and bending the second tape along two intermediate axes, parallel to the second central axis, to form the wings.
6. The method according to claim 2 , wherein the insert profile is wound around the mandrel after the passage of the second tape in the insert profiler.
7. A flexible pipe for conveying a fluid, the flexible pipe comprising:
an inner polymer sheath defining a fluid circulation path with a central axis;
at least one layer of armors, arranged outside the inner sheath;
an inner carcass, positioned in the inner sheath, the inner carcass comprising a first bent tape defining a helical interstice emerging toward the central axis; and
a helical insert with a T-shaped cross-section comprising a rod, inserted in the helical interstice, and two wings protruding on either side of the rod to inwardly close off the helical interstice;
wherein the helical insert is formed of a second bent tape
wherein at least one wing of the two wings comprises a first flank and a second flank bent against the first flank, the first flank and the second flank defining between them an intermediate space.
8. The pipe according to claim 7 , wherein the rod includes the first flank and the second flank bent against the first flank.
9. The pipe according to claim 7 , wherein the rod has a height, measured perpendicularly to the central axis, which is greater than three times the thickness of the first tape.
10. The pipe according to claim 7 , wherein the inner carcass has a first axial play, the helical insert having non-joined turns delimiting a second axial play between them greater than the first axial play.
11. The pipe according to claim 7 , wherein the inner carcass has a first axial play, the rod having a half-axial play at the average pitch in the helical interstice greater than 0.25 times the first axial play.
12. The pipe according to claim 7 , wherein the insert defines at least one fluid passage pipe connecting the interstice to the fluid circulation path.
13. The pipe according to claim 7 , wherein the first bent tape comprises successive turns interlocked to one another, and the first bent tape has a constant thickness.
14. A flexible pipe for conveying a fluid, comprising:
an inner polymer sheath defining a fluid circulation path with a central axis;
at least one layer of armors, arranged outside the inner sheath;
an inner carcass, positioned in the inner sheath, the inner carcass comprising a first bent tape defining a helical interstice emerging toward the central axis; and
a helical insert with a T-shaped cross-section comprising a rod, inserted in the helical interstice, and two wings protruding on either side of the rod to inwardly close off the helical interstice;
wherein the helical insert is formed of a second bent tape, and the rod includes a first flank and a second flank bent against the first flank, the first flank and the second flank defining between them an intermediate space.
15. The pipe according to claim 14 , wherein the rod includes a curved outer segment at the outer free end of the rod, the curved outer segment connecting the first flank to the second flank.
16. The pipe according to claim 14 , wherein a bending radius of the curved outer segment is greater than 0.5 times the thickness of the second tape, the bending radius of the curved outer segment being measured from a center point around which the curved outer segment is bent.
17. The pipe according to claim 14 , wherein a first wing of the two wings protrudes from an inner end of the first flank and a second wing of the two wings protrudes from an inner end of the second flank, the helical insert including a first curved connecting segment connecting the first flank to the first wing and a second curved connecting segment connecting the second flank to the second wing.
18. The pipe according to claim 14 , wherein the bending radius of the curved outer segment is comprised between 0.5 times and 1 time the thickness of the second tape.
19. The pipe according to claim 14 , wherein each connecting segment has a bending radius greater than 0.5 times the thickness of the second tape, the bending radius of each connecting segment being measured from a center part around which each connecting segment is bent.
20. The pipe according to claim 14 , wherein the rod has a height, measured perpendicularly to the central axis, which is greater than three times the thickness of the first tape.
21. The pipe according to claim 14 , wherein the inner carcass has a first axial play, the helical insert having non joined turns delimiting a second axial play between them greater than the first axial play.
22. The pipe according to claim 14 , wherein the inner carcass has a first axial play, the rod having a half-axial play at the average pitch in the helical interstice greater than 0.25 times the first axial play.
23. The pipe according to claim 14 , wherein the insert defines at least one fluid passage pipe connecting the interstice to the fluid circulation path.