Flexible metal pipes with a shrinkable polymer sheath, a process for their fabrication, and their utilization as flexible tubular conduits

• US 5,601,893 A
• Filed: 11/17/1994
• Issued: 02/11/1997
• Est. Priority Date: 09/10/1992
• Status: Expired due to Term

• Current Assignee: Coflexip S.A., Elf Atochem S.A.
• Original Assignee: Coflexip S.A., Elf Atochem S.A.
• Inventors: Hardy, Jean, Strassel, Albert
• Primary Examiner(s): NOLD, CHARLES R
• Application Number:
  US08/340,997
• Time in Patent Office: 817 Days
• Field of Search: 428/35.9, 428/36.91, 138/120, 138/118, 138/122, 138/125, 138/127, 138/131, 138/137-139, 138/143, 138/58, 138/136
• US Class Current: 428/35.9
• CPC Class Codes: F16L 11/083 three or more layers
• CPC Class Codes: F16L 11/14 made of rigid material, e.g. metal or hard plastics
• CPC Class Codes: F16L 11/16 wound from profiled strips or bands
• CPC Class Codes: F16L 9/147 comprising only layers of metal and plastics with or without reinforcement
• CPC Class Codes: Y10T 428/1359 Three or more layers [continuous layer]
• CPC Class Codes: Y10T 428/1393 Multilayer [continuous layer]

Abstract

This invention relates to a flexible metal pipe covered with an impermeable sheath of a shrinkable, preferably semicrystalline polymer or polymers, characterized in that it incorporates between the shrinkable polymer sheath and the metal pipe an intermediate elastomer layer (8), optionally vulcanized or reticulated, and/or a TPE in the form of a continuous tubular sleeve (FIG. 3) or of a tape (FIG. 4 to 6). Sheathed pipes of this type are particularly suitable for flexible pipelines, optionally with suitable supports, for carrying oil and gas.

Claims

1. A flexible metal pipe whose outer surface has interstitial spaces (5), said pipe being covered with a sealing sheath of shrinkable polymer (9), wherein an elastomer layer (8) is provided intermediate between the shrinkable polymer sheath and the metal pipe, said intermediate elastomer layer being in the form either of a continuous tubular envelope or of a tape, and said intermediate elastomer layer being positioned in said interstitial spaces.

2. A flexible metal pipe according to claim 1 comprising interior and exterior metal walls and being arranged with one or more turns having one or more apexes, said pipe being sheathed with a poly(vinylidene fluoride) layer and a polyurethane thermoplastic elastomer layer, said polyurethane layer being interposed in an intermediate position between the external metal wall of the pipe and the poly(vinylidene fluoride) layer.

3. A pipe according to claim 2 whose polyurethane thermoplastic elastomer layer has a Shore A hardness of less than 92.

4. A pipe according to claim 2 whose polyurethane thermoplastic elastomer layer undergoes a reduction in viscosity of at least 60% after 30 days at 120°

C.

5. A pipe according to claim 3 whose polyurethane thermoplastic elastomer layer undergoes a reduction in viscosity of at least 60% after 30 days at 120°

C.

6. A pipe according to claim 2 whose polyurethane thermoplastic elastomer has a viscosity at 200°

C. within the following limits;

space="preserve" listing-type="tabular">______________________________________ Corrected shear rate s.sup.-1 Viscosity in kPa.s ______________________________________ 4.09 0.7-1.3 13.64 0.25-0.85 36.15 0.19-0.78 122.91 0.12-0.70 ______________________________________

7. A pipe according to claim 3 whose polyurethane thermoplastic elastomer has a viscosity at 200°

C. within the following limits;

space="preserve" listing-type="tabular">______________________________________ Corrected shear rate s.sup.-1 Viscosity in kPa.s ______________________________________ 4.09 0.7-1.3 13.64 0.25-0.85 36.15 0.19-0.78 122.91 0.12-0.70 ______________________________________

8. A pipe according to claim 4 whose polyurethane thermoplastic elastomer has a viscosity at 200°

C. within the following limits;

space="preserve" listing-type="tabular">______________________________________ Corrected shear rate s.sup.-1 Viscosity in kPa.s ______________________________________ 4.09 0.7-1.3 13.64 0.25-0.85 36.15 0.19-0.78 122.91 0.12-0.70 ______________________________________

9. A pipe according to claim 5 whose polyurethane thermoplastic elastomer has a viscosity at 200°

C. within the following limits;

space="preserve" listing-type="tabular">______________________________________ Corrected shear rate s.sup.-1 Viscosity in kPa.s ______________________________________ 4.09 0.7-1.3 13.64 0.25-0.85 36.15 0.19-0.78 122.91 0.12-0.70 ______________________________________

10. A pipe according to claim 2 whose intermediate polyurethane thermoplastic elastomer layer has a thickness of 0.1 to 2 mm from the apex of the flexible metal pipe.

11. A pipe according to claim 3 whose intermediate polyurethane thermoplastic elastomer layer has a thickness of 0.1 to 2 mm from the apex of the flexible metal pipe.

12. A pipe according to claim 4 whose intermediate polyurethane thermoplastic elastomer layer has a thickness of 0.1 to 2 mm from the apex of the flexible metal pipe.

13. A pipe according to claim 5 whose intermediate polyurethane thermoplastic elastomer layer has a thickness of 0.1 to 2 mm from the apex of the flexible metal pipe.

14. A pipe according to claim 6 whose intermediate polyurethane thermoplastic elastomer layer has a thickness of 0.1 to 2 mm from the apex of the flexible metal pipe.

15. A pipe according to claim 7 whose intermediate polyurethane thermoplastic elastomer layer has a thickness of 0.1 to 2 mm from the apex of the flexible metal pipe.

16. A pipe according to claim 8 whose intermediate polyurethane thermoplastic elastomer layer has a thickness of 0.1 to 2 mm from the apex of the flexible metal pipe.

17. A pipe according to claim 9 whose intermediate polyurethane thermoplastic elastomer layer has a thickness of 0.1 to 2 mm from the apex of the flexible metal pipe.

26. A flexible tubular conduit suitable for moving liquids under high pressure or at high temperatures incorporating a sheathed pipe according to claim 1.

27. The flexible tubular conduit of claim 26 further comprising armor cladding.

28. A method for the production of off-shore oil or gas which comprises transporting said oil or gas from below the floor of the ocean to the surface of the ocean in a flexible tubular conduit according to claim 1.

18. A flexible pipe consisting essentially of interior and exterior steel walls, said pipe being sheathed with a poly(vinylidene fluoride) layer and a polyurethane thermoplastic elastomer layer, said polyurethane layer being interposed in an intermediate position between the external steel wall of the pipe and the poly(vinylidene fluoride) layer.

19. A flexible pipe according to claim 18 wherein said steel pipe has an internal diameter of from 20 to 400 millimeters, said intermediate polyurethane layer has a thickness of from 0.1 to 2 millimeters, and said poly(vinylidene fluoride) sheathing layer has a thickness of from 1 to 10 millimeters.

20. A flexible pipe according to claim 18 which further comprises a polyurethane layer coated on the internal steel wall of the pipe.

21. A flexible metal pipe whose outer surface has interstitial spaces (5), said pipe being covered with a sealing sheath of shrinkable polymer, wherein an elastomer layer (8) is provided, in the form of either a continuous tubular envelope or a tape positioned in the interstitial spaces (5), intermediate between the shrinkable polymer sheath and the metal pipe, provided that when the shrinkable polymer sheath is composed of poly(vinylidene fluoride), the elastomer layer is not polyurethane.

22. The flexible pipe of claim 21 wherein the shrinkable polymer is a semicrystalline polymer and wherein the elastomer is selected from the group consisting of vulcanized elastomer, reticulated elastomer, thermoplastic elastomer, and mixtures thereof.

23. The flexible pipe of claim 21 wherein the degree of stiffness of the elastomer is less than that of the shrinkable polymer.

24. The flexible pipe of claim 21 wherein the elastomer is selected from the group consisting of silicone elastomers, polyamide thermoplastic elastomers, thermoplastic polyurethanes, ethylene/propylene/diene monomer copolymers, acrylonitrile/butadiene/styrene copolymers, styrene/butadiene/styrene copolymers, methyl methacrylate/butadiene/styrene copolymers, ethylene/carbon monoxide copolymers, ethylene/carbon monoxide/vinyl acetate terpolymers, acrylic rubbers, thermoplastic polyolefins, polyester thermoplastic elastomers, ethylene/ethyl acrylate, ethylene/ethyl acetate, and ethylene/vinyl acetate copolymers and terpolymers, fluorinated elastomers, and mixtures thereof.

25. The flexible pipe of claim 21 wherein the shrinkable polymer is selected from the group consisting of polyolefins, polyamides, polyurethanes, polyureas, polyesters, polyethers, polyoxides, polysulfides, polyether-ether-ketones, copolymers of the preceeding, homopolymers and copolymers of vinylidene fluoride ("VF₂ "), homopolymers and copolymers of trifluoroethylene ("VF₃ "), copolymers and terpolymers comprising two or more different members selected from the group consisting of VF₂, VF₃, chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropene, and ethylene, said shrinkable polymers being used by themselves or mixed with other polymers in which mixtures said shrinkable polymers are present in amounts of at least 70% by weight.

29. A flexible metal pipe comprising interior and exterior metal walls and being arranged with one or more turns having one or more apexes, said pipe being sheathed with a poly(vinylidene fluoride) layer and a polyurethane thermoplastic elastomer layer, said polyurethane layer being interposed in an intermediate position between the external metal wall of the pipe and the poly(vinylidene fluoride) layer.