Thermal insulation of flexible pipes

1. Flexible pipe body for a flexible pipe, said pipe body comprising:

a fluid retaining layer;

at least one tensile armor layer;

at least one extruded thermal insulation layer over an outermost one of said at least one tensile armor layer for preventing liquid water and/or water vapour flowing therethrough; and

an outer shield layer provided directly over the insulation layer.

2. The flexible pipe body as claimed in claim 1 , further comprising:

said insulating layer is a layer of extruded syntactic foam.

3. The flexible pipe body as claimed in claim 2 wherein the extruded syntactic foam layer comprises a plurality of glass micro-spheres.

4. The flexible pipe body as claimed in claim 2 wherein the extruded syntactic foam layer comprises a plurality of plastic micro-spheres.

5. The flexible pipe body as claimed in claim 1 , wherein:

said insulating layer is an extruded polymer resin layer micro foamed with super critical fluids (SCF) or reactive foaming agents.

6. The flexible pipe body as claimed in claim 1 wherein said extruded layer comprises a plurality of circumferential grooves disposed along at least a region of the length of the insulating layer.

7. A flexible pipe body as claimed in claim 6 wherein said grooves are disposed on the inner and/or outer surface of the insulating layer.

8. The flexible pipe body as claimed in claim 1 , further comprising:

a pressure armor layer between the fluid retaining layer and the insulating layer.

9. The flexible pipe body as claimed in claim 1 , further comprising:

a carcass surrounded by the fluid retaining layer of the flexible pipe body.

10. The flexible pipe body as claimed in claim 1 wherein said fluid retaining layer comprises a barrier layer or liner.

11. A flexible pipe comprising the flexible pipe body as claimed in claim 1 , further comprising:

two end fittings each located at a respective one of two ends of the pipe body, wherein said insulating layer comprises a continuous layer extending between the end fittings.

12. The flexible pipe as claimed in claim 11 , further comprising:

at least one seal in each end fitting, each seal being disposed to form a seal between a respective end fitting and the insulating layer to thereby provide a liquid water barrier layer between a region radially within the insulating layer and a further region radially outside the insulating layer.

13. A riser flowline or jumper comprising the flexible pipe as claimed in claim 11 .

14. A method of manufacturing flexible pipe body, the method

comprising: providing a tubular fluid retaining layer;

forming at least one tensile armor layer over the fluid retaining layer;

extruding a thermally insulating layer over an outermost one of said at least one tensile armor layer for preventing liquid water and/or water vapour flowing therethrough; and

forming an outer shield layer directly over the insulating layer.

15. The method as claimed in claim 14 , further comprising:

extruding the insulating layer directly onto the outer tensile armor layer.

16. The method as claimed in claim 15 further comprising:

extruding the insulating layer by extruding a layer of syntactic foam comprising a plurality of plastic micro-spheres.

17. The method as claimed in claim 16 wherein said micro-spheres are expandable plastic micro-spheres.

18. The method as claimed in claim 15 further comprising:

extruding the insulating layer by extruding a layer of syntactic foam comprising a plurality of glass micro-spheres.

19. The method as claimed in claim 15 further comprising:

extruding the insulating layer by extruding a polymer resin layer comprising super critical fluids (SCF) or a reactive foaming agent.

20. The method as claimed in claim 14 further comprising:

forming circumferential grooves at an inner and/or outer surface of the insulating layer subsequent to exit of the pipe from a dye during the extrusion process but prior to cooling.

21. The method as claimed in claim 14 wherein the fluid retaining layer comprises a barrier layer or liner.

22. A method of providing a flexible pipe, the method comprising:

securing a respective end fitting to each of two free ends of a portion of flexible pipe body; and

during the securing step, sealing a respective end fitting to an extruded thermally insulating layer formed in the flexible pipe body over an outermost tensile armor layer and directly under an outer shield layer thereby providing a liquid water barrier from end fitting to end fitting along the length of the flexible pipe and preventing liquid water and/or water vapour flowing therethrough.

23. A method comprising:

providing a flexible pipe body comprising a fluid retaining layer, at least one tensile armor layer, at least one extruded thermal insulation layer over an outermost one of said at least one tensile armor layer, the thermal insulation layer suitable for preventing liquid water and/or water vapour flowing therethrough, and an outer shield layer directly over the insulation layer; and

transporting fluid through the pipe body.