AU2005200068B2 - Flexible pipe and method of manufacturing same - Google Patents

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A DIVISIONAL PATENT

ORIGINAL

TO BE COMPLETED BY APPLICANT Name of Applicant: Actual Inventors: Address for Service: Invention Title: WELLSTREAM INTERNATIONAL LIMITED Dana, J. Fraser; Robert, G. Hoefling; Mark Kalman; and Alan McCone CALLINAN LAWRIE, 711 High Street, Kew, Victoria 3101, Australia FLEXIBLE PIPE AND METHOD OF MANUFACTURING

SAME

The following statement is a full description of this invention, including the best method of performing it known to us:- 10/01/05,eh14724.cov,1 tn FLEXIBLE PIPE AND METHOD OF MANUFACTURING SAME SThis application claims priority of provisional application S.N. 60/163,908 filed November 5, 1999.

The present invention relates to a relative low-cost flexible pipe formed by multiple layers 00 of different materials and suitable for use in subsea and land-based applications.

INO

SBrief Description of the Drawings Fig. 1 is a longitudinal sectional view of a flexible pipe according to an embodiment of the present invention Fig. 2 is a longitudinal sectional view of a flexible pipe according to another embodiment of the present invention.

Figs. 3A 3C are longitudinal sectional views of alternative embodiments of a layer of the pipes of the embodiment of Figs. 1 and 2.

Detailed Description With reference to Fig. 1, a flexible pipe according to an embodiment of the present invention is shown, in general by the reference numeral 10. The pipe 10 is formed by an inner tubular member, preferably in the form of a plastic sheath 12 for conveying fluid through its bore. The sheath may be formed in a conventional manner using polymers, or the like.

A layer 14 is wrapped around the sheath 12 and provides resistance to internal pressure, hydrostatic collapse and crush. The layer 14 is formed by helically wrapping a continuous metal strip, preferably formed of carbon steel, with adjacent windings being interlocked, to form a flexible layer that provides significant hoop and axial strength. The layer 14 is marketed by the assignee of the present invention, Wellstream International Limited, under the "Flexlok" trademark.

10/01/05,eh 14724.spc,2 tt A wrapped wire assembly 16 extends over the layer 14 and consists of a series of wires 16a Shelically wrapped around the exterior of the layer 14 to form a first tensile layer, and an Sadditional series of wires 16b wrapped around the first series of wires 16a to form a second c, tensile layer extending over the first tensile layer. The wires 16a and 16b have a substantially circular cross section, and are wound at a relatively high lay angle to provide significant hoop strength and axial strength. Preferably, at least a portion of the wires 16a 00 and 16b are formed by carbon steel with an anodic coating. It is noted that the layer 14 Sprevents the expansion of the sheath 12 into gaps formed between the wires of the tensile layers 16a and 16b.

One or more layers of a tape 18 are helically wrapped over the wire assembly 16. The tape 18 can be formed by plastic or metal and can be reinforced with glass, metal or a stronger plastic. Although not shown in the drawings, it is understood that the tape 18 can also extend between the layer 14 and the wire assembly 16, and between the series of wires 16a and 16b.

A protective outer insulative sheath 20 extends over the tape 18 and is preferably extruded over the tape 18 in a conventional manner, with the tape providing a smooth surface for the extrusion. The sheath 20 is optional and is required only when the tape 18 is inadequate to protect the remaining components of the pipe Fig. 2 depicts a pipe 10' that is similar to the pipe 10 of Fig. 1 and includes some components of Fig. 1 which are given the same reference numerals. In the embodiment of Fig. 2, a wrapped wire assembly 26 extends over the layer 14 and consists of a series of wires 26a and 26b which are substantially rectangular in cross section. The wires 26a are helically wrapped around the exterior of the layer 14 to form a first tensile layer, and the wires 26b wrapped around the first series of wires 26a to form a second tensile layer extending over the first tensile layer.

According to an embodiment of the method of the invention, the rectangular profile of the wires 26a and 26b is achieved by unwinding the coiled wires from a mandrel, or the like, and passing the wires through opposed rollers which flatten the wires to a substantially rectangular cross section.

10/01/05,eh14724.spc,3 -4n According to an alternate method of forming the wires 26a and 26b an elongated sheet is Spayed out from a coil and a plurality of spaced cutters are placed in the path of the sheet to Sslit the sheet in to a plurality of wires. The cutters are spaced in a manner to form a plurality of wires having a rectangular cross section.

Both of the above methods avoid the high expense of specialised rolling mills in which 00coils of round carbon steel wire are processed through repeated roll forming and heat Streating operations.

Also, in the embodiment of Fig. 2 it is understood that wrapped tape, identical to the tape C layer 18, can also extend between the layer 14 and the wire assembly 26, and between the series of wires 26a and 26b.

Also according to the embodiment of Fig. 2, an inner layer 28 is provided inside the sheath 12. The layer 28 is preferably formed by a plurality of helically wrapped, corrugated and/or interlocked strips to provide additional collapse and radial compression resistance.

If the layer 28 is added, the sheath 12 would be extruded over the outer surface of the layer 24.

It is emphasised that both the wire assembly 26 and the layer 28 can be included in the pipe and/or 10', or one can be included without the other.

Figs. 3A 3C are alternative embodiments of the layer 14 which can be used with the pipe and/or the pipe 10'. Referring to Fig. 3A, a continuous metal strip 30, preferably of carbon steel, is helically wrapped around the adjacent inner member (not shown). Two adjacent inner windings are shown by the reference numerals 30a and 30b, and three adjacent outer windings are shown by the reference numerals 30c, 30d and respectively. The wrapping of the strip 30 is such that the winding 30d overlaps the windings 30a and 30b, the winding 30c overlaps the winding 30a and its adjacent inner winding (not shown), and the winding 30e overlaps the winding 30b and its adjacent inner winding (not shown), and so on. The strip 30 is wound in this manner for the length of the pipes 10 or 10', and it is understood that the number of radially spaced windings, and therefore the thickness of the layer thus formed can vary.

10/01/05,eh14724.spc,4 t According to the embodiment of Fig. 3B, a continuous metal strip 34, preferably of carbon Ssteel, is helically wrapped around the adjacent inner member (not shown). The strip 34 is Sshaped, or formed, in any known manner to form a cross section having a first substantially horizontal inner portion 34a, and second substantially horizontal portion 34b that is spaced radially outwardly from the inner portion 34a, and a bent portion 34c extending between the portions 34a and 34b. The strip 34 is preferably of carbon steel and is helically 00 wrapped around the adjacent inner member (not shown). The wrapping of the strip 34 is such that the portion 34b overlaps the inner portion of its adjacent winding, and the portion 34a is overlapped by the outer portion of its adjacent winding, to thus achieve an interlocking effect. The strip 34 is wrapped for the length of the pipes 10 or 10'; and it is understood that the number of radially spaced windings, and therefore the thickness of the layer thus formed can vary.

According to the embodiment of Fig. 3c, a continuous metal strip 38, preferably of carbon steel, is helically wrapped around the adjacent inner member (not shown). The strip 38 is shaped, or formed, in any known manner to form a cross section having a convex portion 38a extending from a concave portion 38b. The wrapping of the strip 38 is such that the convex portion 38a overlaps the concave portion of its adjacent winding and the concave portion 38a is overlapped by the convex portion of its adjacent winding to thus achieve an interlocking effect. The strip 38 is wrapped for the length of the pipes 10 or 10', and it is understood that the number of radially spaced windings, and therefore the thickness of the layer thus formed can vary.

Variations 1. In each of the above embodiments, additional tensile layers of wires can be provided in addition to the series of wires 16a and 16b in the pipe 10 and the series of wires 26a and 26b in the pipe 2. The carbon steel strip layer 14 can be omitted from each of the above embodiments in which case the first tensile layer 16a would be wound directly onto the sheath 12.

10/01/05,eh 14724.spc,5 tn 3. If the carbon steel strip is omitted, as discussed in paragraph 2, above, an optional 0 Swrapped tape, similar to the tape 18 could be provided that extends between the sheath 12 and the first tensile layer 16a.

4. The adjacent windings of the strip forming the layer 14 do not have to be interlocked.

00 \O In extremely hostile environments, an outer layer similar to the layer 14 can be placed around the sheath 20 for added protection, in each of the embodiments.

6. In extremely hostile environments, an outer layer similar to the layer 14 can be placed around the sheath 20 for added protection.

It is understood that spatial references, such as "under", 'over", "between", "outer", "inner" and "surrounding" are for the purpose of illustration only and do not limit the specific orientation or location of the layers described above.

Since other modifications, changes, and substitutions are intended in the foregoing disclosure, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.

Where the terms "comprise", "comprises", "comprised" or "comprising" are used in this specification, they are to be interpreted as specifying the presence of the stated features, integers, steps or components referred to, but not to preclude the presence or addition of one or more other feature, integer, step, component or group thereof.

10/0 /05,eh I 4724.spc,6

Claims (16)

1. A method of manufacturing a pipe, including providing a plurality of coiled _n wires having a circular cross section, whereby uncoiling the wires while passing the uncoiled portions of the wires through opposed rollers to form the circular cross section into a substantially rectangular cross section, and wrapping at least a portion of the wires 0 around a tubular member to form a tensile layer.

2. The method of claim 1 wherein a portion of the wires are wrapped around the tubular member, and further including wrapping another portion of the wires around the exterior of the wrapped portion of the wires to form an additional tensile layer extending over the first-mentioned tensile layer.

3. The method of claim 1 further including winding a metal strip over the tubular member before the step of wrapping, the wires being wrapped over the metal strip.

4. The method of claim 3 wherein the metal strip has a constant thickness. The method of claim 3 wherein the adjacent windings of the metal strip are interlocked.

6. The method of claim 4 wherein the cross section of the metal strip has a substantially horizontal inner portion, a substantially horizontal outer portion that is spaced radially outwardly from the inner portion, and a bent portion extending between the inner and outer portions.

7. The method of claim 4 wherein the wrapping of the metal strip is such that outer portions of the metal strip overlap the corresponding inner portions of their adjacent windings, and the inner portions of the metal strip are overlapped the corresponding outer portions of their adjacent windings to achieve an interlocking effect.

8. The method of claim 4 wherein the cross-section of the metal strip has a convex portion extending from a concave portion. 10/01/05,eh14724.spc,7 S9. The method of claim 8 wherein the wrapping of the metal strip is such that Sthe convex portions overlap the corresponding concave portions of their adjacent winding, Sand the concave portions are overlapped by the corresponding convex portion of their adjacent windings to achieve an interlocking effect. The method of claim 1 further including forming a sheath over the wrapped 00 wires.

11. A method of manufacturing a pipe, including providing a sheet of coiled material, whereby uncoiling the sheet while passing the uncoiled portion of the sheet through a plurality of spaced cutters in the path of the sheet to cut the sheet into a plurality of wires each having a substantially rectangular cross section, and wrapping at least a portion of the wires around a tubular member to form a tensile layer.

12. The method of claim 11 wherein a portion of the wires are wrapped around the tubular member, and further including wrapping another portion of the wires around the exterior of the wrapped portion of the wires to form an additional tensile layer extending over the first-mentioned tensile layer.

13. The method of claim 11 further including winding a metal strip over the tubular member before the step of wrapping, the wires being wrapped over the metal strip.

14. The method of claim 13 wherein the metal strip has a constant thickness.

15. The method of claim 13 wherein the adjacent windings of the metal strip are interlocked.

16. The method of claim 13 wherein the cross-section of the metal strip has a substantially horizontal inner portion, a substantially horizontal outer portion that is spaced radially outwardly from the inner portion, and a bent portion extending between the inner and outer portions.

17. The method of claim 13 wherein the wrapping of the metal strip is such that outer portions of the metal strip overlap the corresponding inner portions of their adjacent 10/0 1/05,eh 14724. spc,8 -9- tt windings, and the inner portions of the metal strip are overlapped the corresponding outer Oportions of their adjacent windings to achieve an interlocking effect.

18. The method of claim 13 wherein the cross-section of the metal strip has a convex portion extending from a concave portion. 00 19. The method of claim 18 wherein the wrapping of the metal strip is such that the convex portions overlap the corresponding concave portions of their adjacent winding, and the concave portions are overlapped by the corresponding convex portion of their adjacent windings to achieve an interlocking effect. The method of claim 11 further including forming a sheath over the wrapped wires.

21. A method of manufacturing a pipe, substantially as hereinbefore described with reference to the accompanying drawings. Dated this 10 th day of January, 2005 WELLSTREAM INTERNATIONAL LIMITED By Their Patent Attorneys CALLINAN LAWRIE 10/0 1/05,eh 14724.spc,9