Method for producing a carcass, a method of producing a flexible pipe and a flexible pipe

Patent metadata

Field	Value
Publication number	US-12011750-B2
Application number	US-202017768085-A
Country	US
Kind code	B2
Filing date	Oct 14, 2020
Priority date	Oct 15, 2019
Publication date	Jun 18, 2024
Grant date	Jun 18, 2024

Abstract

A method of producing a carcass for a flexible pipe, the carcass and a flexible pipe with the carcass includes providing at least one first metallic strip a cover metallic strip. Shaping the first strip to have a profile with a first fold adapted to face towards the carcass axis and a second fold adapted to face away from the carcass axis. Pretreating an anchor width section of the cover strip including a weakening treatment of resistance against length extension and/or a length extension of the pretreated part of the anchor width section. Inserting the anchor width section of the cover strip into the first fold, ensuring that a cover width section of the cover strip extends beyond the second fold. Helically winding the first metallic strip and the cover strip, to provide that the first fold engages and interlocks with the second fold and that the cover width section covers a helical interstice between windings of the first metallic strip on the inner side of the carcass.

First claim

What is claimed is:

1. A method of producing a carcass for a flexible pipe, the method comprising:
providing at least one first metallic strip and shaping said first strip to have a profile with a first fold adapted to face towards said carcass axis and a second fold adapted to face away from said carcass axis,
providing a cover metallic strip with a length and a width,
inserting an anchor width section of said cover strip into said first fold,
providing that a cover width section of said cover strip extends beyond said second fold, and
helically winding said first metallic strip and said cover strip, to provide that said first fold engages and interlocks with said second fold and that said cover width section covers a helical interstice between windings of the first metallic strip on the inner side of the carcass,
wherein at least a part of said anchor width section of said cover strip is subjected to a pretreatment before insertion into said first fold, and
wherein said pretreatment comprising a weakening treatment of resistance against length extension and/or a length extension of the pretreated part of the anchor width section.

2. The method of claim 1 , wherein the first fold of the first strip has a depth and a width at said depth, and wherein said pretreated part of said anchor width section comprises at least a width corresponding to said width at said depth of the first fold.

3. The method of claim 1 , wherein the first fold of the first strip has a depth and curved section between respectively a first edge and a second edge along said depth, and wherein said pretreated part of said anchor width section comprises at least a width corresponding to said width at said depth of the first fold and one or both of said curved sections.

4. The method of claim 1 , wherein said pretreatment comprises stretching the material to increase in length, preferably by preforming at least a part of the anchor width section to conform to said first fold.

5. The method of claim 1 , wherein said pretreatment comprises providing weakening lines, said weakening lines are substantially perpendicular to the length of the cover strip.

6. The method of claim 5 , wherein said weakening lines are provided by cutting, wherein the cutting comprises cutting fully through the strip material, or
cutting out strips of the treated part of the anchor width section.

7. The method of claim 5 , wherein at least a part of said weakening lines are not fully penetrating the strip material.

8. The method of claim 1 , wherein the first metallic strip is thicker than the cover strip.

9. The method of claim 1 , wherein the method comprises providing that the major part of the anchor width section of said cover strip is conforming with an inner surface of said first fold and held in fixed position by the second fold of the first metallic strip in a consecutive winding.

10. The method of claim 1 , wherein said first metallic strip has a first edge forming part of said first fold and a second edge forming part of said second fold, wherein the method comprises forming said first metallic strip to have a lip adjacent to said first edge, wherein said anchor width section of said cover strip located in the first fold extends beyond said lip, to be located between said lip and said second fold which is interlocked with said first fold.

11. The method of claim 1 , wherein said first metallic strip has a first edge forming part of said first fold and a second edge forming part of said second fold, wherein said anchor width section of said cover strip located in the first fold extends to the first edge said first metallic strip.

12. The method of claim 1 , wherein said method comprises applying a pulling force F to said cover strip during the insertion of the anchor width section of said cover strip into said first fold and/or during the helically winding of said first metallic strip and said cover strip, wherein the pulling force is sufficient to stretching at least a portion of the anchor width section.

13. The method of claim 1 , wherein said pretreatment comprises providing weakening lines in at least a part of said anchor width section of said cover strip by partly or fully cutting through the strip material and wherein the method comprises subjecting at least a portion of said anchor width section to tensile strain during the insertion of the anchor width section of said cover strip into said first fold and/or during the helically winding of said first metallic strip and said cover strip, wherein said tensile strain is sufficient to provide a deformation of a plurality of said weakening lines, wherein said deformation of each of said plurality of weakening lines comprises providing that a pair of a first and a second opposite edges of a weakening line separates and/or increases distance to each other.

14. The method of claim 13 , wherein said cover strip has a first edge forming an edge of said cover width section and a second edge forming an edge of said anchor width section and wherein said weakening lines individually from each other are perpendicular or up to 10 degrees from being perpendicular to the anchor width section edge and wherein said weakening lines comprises parallel straight lines.

15. The method of claim 1 , further comprising, producing the flexible pipe:
extruding a polymer layer onto the carcass;
applying one or more armor layers around the polymer layer; and
optionally applying one or more polymer layers.

16. A flexible pipe for conveying a fluid, said pipe comprising a center axis along the length of the pipe and from the inside and out;
a carcass,
an internal pressure sheath and
at least one armor layer,
said carcass comprises at least one first metallic strip and a cover strip, said first metallic strip comprises a first fold facing towards said center axis and a second fold facing away from said center axis, said cover strip comprises an anchor width section and a cover width section, and wherein said first and said second fold of said first strip being interlocked with said anchor width section anchored in said interlocking and wherein said anchor width section comprises weakening lines in at least a part of said anchor width section of said cover strip, wherein said weakening lines are fully penetrating the material of said anchor width section.

17. The flexible pipe of claim 16 , wherein said weakening lines comprises cuts into said cover strip material.

18. The flexible pipe of claim 16 , wherein each of a plurality of said weakening lines comprises a pair of a first and a second opposite edges which are at least partly separated from each other to provide a through going opening in the strip material.

19. The flexible pipe of claim 16 , wherein said first metallic strip has a first edge forming part of said first fold and a second edge forming part of said second fold, wherein said metallic strip is shaped to have a lip adjacent to said first edge, wherein said anchor width section of said cover strip located in the first fold extends beyond said lip, to provide that a portion of the anchor width section is located between said lip and said second fold which is interlocked with said first fold.

20. A method of producing a carcass for a flexible pipe, the method comprising:
providing at least one first metallic strip and shaping said first strip to have a profile with a first fold adapted to face towards said carcass axis and a second fold adapted to face away from said carcass axis,
providing a cover metallic strip with a

Assignees

• Nat Oilwell Varco Denmark Is

Inventors

• Koch Lasse Tang

Classifications

• F16L11/16 Primary

  wound from profiled strips or bands · CPC title

• B21C37/123

  of coated strip material; Making multi-wall tubes · CPC title

• B21C37/126

  Supply, or operations combined with supply, of strip material · CPC title

• B21C37/124

  the tubes having a special shape, e.g. with corrugated wall, flexible tubes · CPC title

• B21C37/121 Primary

  with seams being neither welded nor soldered · CPC title