Flexible pipe having a carcass layer

1. Flexible pipe body for transporting fluids from a sub-sea location, comprising:

a carcass layer comprising adjacent interlocked annular elements, wherein the annular elements comprise a plurality of independent hoop elements disposed in a side-by-side coaxial relationship along a bore region and wherein each hoop element comprises a body portion that extends around an inner circumference of the bore region and a channel region encapsulated by the body portion and provided within the body portion, wherein the body portion is a substantially Z-shaped housing encasing said channel region and comprises a nose region on each of a first end and further end of the Z-shape, wherein the nose regions are formed by each of the first end and further end being turned inwardly towards an imaginary centre line running across a cross section of the body portion; and

wherein the nose regions of each hoop element provides means to interlock adjacent hoop elements together.

2. The flexible pipe body as claimed in claim 1 , wherein the channel region is hollow or is substantially filled with a material that dissolves within a predetermined period of time.

3. The flexible pipe body as claimed in claim 1 , wherein the channel region is substantially filled with an insulating material or a strengthening material.

4. The flexible pipe body as claimed in claim 1 , wherein the body portion of each hoop element is a closed ring having a circular outer surface.

5. The flexible pipe body as claimed in claim 4 , wherein the body portion of each hoop element in the carcass layer is formed from an identical material.

6. The flexible pipe body as claimed in claim 4 , wherein the body portion of a first plurality of hoop elements in the carcass layer is formed from a first material different from a material used to form a further plurality of hoop elements in the carcass layer.

7. The flexible pipe body as claimed in claim 4 , wherein a channel region of a first plurality of hoop elements is filled with a first material and a channel region of a further plurality of hoop elements is filled with a further material different from said first material.

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

the nose regions comprise a male connection region and a female connection region disposed one on each end of the Z-shaped housing encasing said channel region, the male connection region of a first hoop element being locatable in the female connection region of an adjacent hoop element to thereby interlock adjacent hoop elements.

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

the carcass layer further comprises a plurality of connecting rings having a substantially H-shaped cross section, a respective connecting ring being located between adjacent hoop elements and being operable to engage with the nose region of adjacent annular elements thereby locking adjacent hoop elements together.

10. The flexible pipe body as claimed in claim 9 , wherein:

one of the nose regions of each hoop element comprises a downwardly turned nose region and the other nose region of each hoop element comprises an upwardly turned nose region; and

a downwardly turned nose region of a first hoop element rides within a substantially U-shaped channel defined by an upper surface of the H-shaped connecting ring and an upwardly turned nose region of an adjacent hoop element rides in a substantially inverted U-shaped channel defined by a lower surface of the H-shaped connecting ring.

11. The flexible pipe body as claimed in claim 1 wherein the body portion comprises a first plate element and a further plate element, the first plate element and further plate element being disposed in a spaced apart and substantially parallel relationship at a centre region of each plate element and secured together at either side of the centre region to thereby define said channel region between the plate elements.

12. The flexible pipe body as claimed in claim 11 , wherein a cross section of each plate element has a substantially constant thickness.

13. The flexible pipe body as claimed in claim 11 , wherein the first and further plate elements are secured together at a first side of the channel region via an edge region of the further plate element and an intermediate region of the first plate element, said intermediate region extending to provide the inwardly turned nose region thereby forming a hooked region of the first plate element.

14. The flexible pipe body as claimed in claim 13 , wherein the first and further plate elements are secured together at a second side of the channel region via an edge region of the first plate element and an intermediate region of the further plate element, said intermediate region of the further plate element extending to provide the inwardly turned nose region thereby forming a hooked region of the further plate element.

15. The flexible pipe body as claimed in claim 14 , wherein the hooked regions of the first plate element and the further plate element are turned inwardly towards an imaginary centre line running across the cross section of the hoop element whereby the hooked region of the first plate element of a first hoop element interlocks with the hooked region of the further plate element in an adjacent hoop element.

16. The flexible pipe body as claimed in claim 15 , wherein a width to thickness ratio of the hoop element is more than 2:1.

17. A flexible pipe for transporting fluids from a sub-sea location, comprising:

the flexible pipe body as claimed in claim 1 ; and

one or more end fittings.

18. A jumper, riser or flow line comprising the flexible pipe as claimed in claim 17 .

19. A method of manufacturing flexible pipe body, comprising the steps of:

locating independent hoop elements in a side-by-side coaxial relationship;

interlocking adjacent hoop elements by urging adjacent hoop elements together thereby nesting a hook region of a first hoop element in a valley region of an adjacent element; and

via each hoop element providing an annular channel region encircling a bore of the flexible pipe body;

wherein each hoop element comprises a body portion that extends around an inner circumference of the bore and encapsulates a respective channel region, wherein the body portion is a substantially Z-shaped housing encasing said channel region and comprises a nose region on each of a first end and further end of the Z-shape, wherein the nose regions are formed by each of the first end and further end being turned inwardly towards an imaginary centre line running across a cross section of the body portion, wherein the nose regions define the hook region and the valley region of the hoop element.

20. The method as claimed in claim 19 , further comprising the steps of:

interlocking adjacent hoop elements in which a respective channel region is substantially filled with an insulating material or a strengthening material.

21. A method of manufacturing flexible pipe body, comprising the steps of:

locating independent hoop elements in a side-by-side coaxial relationship along a bore region of the flexible pipe body;

interlocking adjacent hoop elements by urging adjacent hoop elements together; and

arranging the body portion of each hoop element to interlock adjacent hoop elements together;

wherein each hoop element comprises a body portion that extends around an inner circumference of the bore region and a channel region encapsulated by the body portion and provided within the body portion, wherein the body portion is a substantially Z-shaped housing encasing said channel region and comprises a nose region on each of a first end and further end of the Z-shape, wherein the nose regions are formed by each of the first end and further end being turned inwardly towards an imaginary centre line running across a cross section of the body portion.