The present invention relates to a flexible pipe and a method of manufacturing a flexible pipe of a type which may be used to convey the production fluids associated with the oil and gas industry. In particular, but not exclusively, the present invention relates to flexible pipe body having a layer formed by interlocking adjacent windings of a helically wound tape using an insert embedded in, and projecting from, the body of the tape.

Traditionally, flexible pipe is utilised to transport production fluids, such as oil and/or gas and/or water, from one location to another. Flexible pipe is particularly useful in connecting a sub-sea location to a further sub-sea location or a sea level location. Flexible pipe is generally formed as an assembly of a segment of flexible pipe body and one or more end fitting in which ends of the flexible pipe body are terminated. The pipe body is typically formed as a composite of tubular layers of material that form a fluid and pressure containing conduit. The pipe structure allows large deflections without causing bending stresses that impair the pipe's functionality over a desired lifetime. The pipe body is generally, but not necessarily, built up as a composite structure including metallic and polymer layers. Flexible pipe may be utilised as a flow line overland and/or at a sub-sea location. Flexible pipe may also be used as a jumper or riser.

In many conventional flexible pipes of this type, a "pressure armour layer" is utilised to help reinforce an internal pressure sheath such as a fluid barrier layer or liner and prevent radial expansion and burst through due to differential pressure conditions acting across the pipe. The pressure armour layer is thus important for the pressure retainment capability of the flexible pipe. The pressure armour layer may also act as a reinforcement layer providing some collapse resistance. Conventionally a pressure armour layer is formed by helically winding one or more tapes about an underlying layer whereby adjacent tape windings interlock with a claw or hook- shaped region at one edge of a tape winding interlocking with a corresponding recessed or valley-shaped region of an opposite edge of an adjacent winding. However, it is noted that in order to achieve adequate interlocking many prior art solutions require the use of tapes which can be difficult to handle during a manufacturing process. This can be caused by the asymmetry of the tapes. Also, the profile of the pressure armour layer places restrictions upon the designs of tape which can be utilised. The armour layer produced by winding the tape must be strong in compression as it is squeezed between radially inner and outer layers and must also provide sufficient strength to avoid, or at least limit, separation of adjacent windings in use.

It is an aim of the present invention to at least partly mitigate the above-mentioned problems.

It is an aim of certain embodiments of the present invention to provide flexible pipe body including at least one layer, for example a pressure armour layer, which is convenient to manufacture.

It is an aim of certain embodiments of the present invention to provide flexible pipe body including a reinforcing layer which is good at resisting compressive forces and which will also wholly or at least partially resist separation of adjacent windings used to form the layer.

It is an aim of certain embodiments of the present invention to provide a tape which can be helically wound around an underlying layer and which is manufactured having in mind the separate functions that the tape must fulfil so as to optimise materials used to create the tape according to the separate functions.

It is an aim of certain embodiments of the present invention to provide a windable body that has an innate helical shape and which can be wound so that adjacent windings interlock so as to support an underlying layer. According to a first aspect of the present invention there is provided flexible pipe body for transporting production fluids, comprising:

at least one layer of helically wound tape, adjacent windings in the layer of tape being interlocked by a first connector region of a winding interconnected with a complementary further connector region of an adjacent winding; wherein

the first and further connector regions are provided by respective regions of at least one insert member embedded in, and projecting from, a body portion of the tape.

Aptly, the body portion comprises a curved pultrusion having an innate helical shape. Aptly, the body portion comprises an extrusion cured fully only subsequent to being wound to form a layer. Aptly, the body portion is a composite body portion comprising at least one reinforcing filament element in a matrix material. Aptly, the at least one reinforcing filament element comprises a plurality of randomly orientated fibres in the matrix material.

Aptly, the at least one reinforcing filament element comprises a plurality of fibres commonly aligned in the matrix material.

Aptly, a density of the randomly orientated fibres in the matrix is greater in regions of the body portion proximate to the embedded insert member than in remaining regions of the body portion remote from the insert member. Aptly, the body portion comprises a substantially flat upper and lower abutment surface that, in use, abut against radially outer and radially inner layers of the pipe body respectively.

Aptly, the body portion of the tape has a cross-section that is substantially l-shaped or square-shaped or rectangular-shaped or U-shaped or T-shaped or is elliptical in shape.

Aptly, the at least one embedded insert member comprises a single elongate unitary body.

Aptly, the elongate unitary body comprises:

a central region comprising a plurality of securing elements extending along a length of the central region;

a first edge region comprising the first connector region of a winding, extending from a first side of the central region along the length of the central region; and

a further edge region comprising the further connector region of an adjacent winding, extending from a further side of the central region along the length of the central region.

Aptly, each securing element is a throughhole or recess in a surface of the central region.

Aptly, each securing element is a protrusion extending from a surface of the central region. Aptly, the central region of the unitary body is embedded in a middle region or a surface region of the body portion of the tape and the edge regions of the unitary body extend out of side regions of the body portion of the tape. Aptly, the at least one embedded insert member comprises a plurality of elongate unitary bodies.

Aptly, each unitary body comprises:

a first edge region and central region at least one of which includes a plurality of securing elements extending along a length of the unitary body; and

a further edge region, comprising a one of the first connector region of a winding or further connector region of an adjacent winding.

Aptly, each connector region comprises a respectively orientated L-shaped or C-shaped or spiral-shaped or hook-shaped end.

Aptly, each at least one embedded insert member is manufactured from a metallic or polymeric material, or composite material. Aptly each at least one embedded insert member is manufactured from a bi-stable composite material.

Aptly, the flexible pipe body further comprises an internal pressure sheath, wherein said at least one layer comprises a pressure armour layer over the internal pressure sheath.

Aptly, the internal pressure sheath comprises a barrier layer or liner.

According to a second aspect of the present invention there is provided a flexible pipe comprising at least one end fitting and a segment of flexible pipe body that comprises at least one layer of helically wound tape, adjacent windings in the layer of tape being interlocked by a first connector region of a winding interconnected with a complementary further connector region of an adjacent winding; wherein

the first and further connector regions are provided by respective regions of at least one insert member embedded in, and projecting from, a body portion of the tape. According to a third aspect of the present invention there is provided a riser, flowline or jumper comprising a flexible pipe having at least one end fitting and a segment of flexible pipe body comprising:

at least one layer of helically wound tape, adjacent windings in the layer of tape being interlocked by a first connector region of a winding interconnected with a complementary further connector region of an adjacent winding; wherein

the first and further connector regions are provided by respective regions of at least one insert member embedded in, and projecting from, a body portion of the tape. According to a fourth aspect of the present invention there is provided use of a flexible pipe comprising at least one end fitting and a segment of flexible pipe body comprising at least one layer of helically wound tape, adjacent windings in the layer of tape being interlocked by a first connector region of a winding interconnected with a complementary further connector region of an adjacent winding; wherein

the first and further connector regions are provided by respective regions of at least one insert member embedded in, and projecting from, a body portion of the tape for the transportation of production fluids.

According to a fifth aspect of the present invention there is provided an elongate tape for forming a layer of interlocked windings in flexible pipe body, the tape comprising:

a body portion; and

at least one insert member embedded in the body portion; wherein

regions of the insert member project from the body portion to provide respective first and further complementary connector regions that are each interconnectable with a corresponding connector region of an adjacent winding when the tape is helically wound to provide a flexible pipe body layer.

Aptly, the body portion comprises a curved pultrusion having an innate helical shape. Aptly, the body portion is a composite body portion comprising at least one reinforcing filament in a matrix material.

Aptly, the at least one reinforcing filament element comprises a plurality of randomly orientated fibres in the matrix material. Aptly, the at least one reinforcing filament element comprises a plurality of commonly aligned fibres in the matrix material.

Aptly, a density of the randomly orientated fibres in the matrix is greater in regions of the body portion proximate to the embedded insert member than in remaining regions of the body portion remote from the insert member.

Aptly, the body portion comprises a substantially flat upper and lower abutment surface that, in use, abut against radially outer and radially inner layers of flexible pipe body.

Aptly, the body portion of the tape has a cross-section that is substantially l-shaped or square-shaped or rectangular-shaped or U-shaped or T-shaped or is elliptical in shape.

Aptly, the at least one embedded insert member comprises a single elongate unitary body.

Aptly, the elongate unitary body comprises:

a central region comprising a plurality of securing elements extending along a length of the central region; a first edge region comprising the first connector region of a winding, extending from a first side of the central region; and

a further edge region comprising the further connector region of an adjacent winding, extending from a further side of the central region.

Aptly, each securing element is a hole or recess in a surface of the central region. Aptly, each securing element is a protrusion extending from a surface of the central region.

Aptly, the central region of the unitary body is embedded in a middle region or a surface region of the body portion of the tape and the edge regions of the unitary body extend out of side regions of the body portion of the tape.

Aptly, the at least one embedded insert member comprises a plurality of elongate unitary bodies.

Aptly, each unitary body comprises:

a first side including a plurality of securing elements extending along a length of the first side of the unitary body; and a further edge region, comprising a one of the first connector region of a winding or further connector region of an adjacent winding.

Aptly, each connector region comprises a respectively orientated L-shaped or C-shaped or spiral-shaped or hook-shaped end.

Aptly, each at least one embedded insert member is manufactured from a metallic or polymeric material or composite material. Aptly each at least one embedded insert member is manufactured from a bi-stable composite material.

According to a sixth aspect of the present invention there is provided a method of manufacturing flexible pipe body, comprising the steps of:

providing at least one tape comprising a body portion and at least one insert member embedded in the body portion wherein regions of the insert member project from the body portion to provide respective first and further complementary connector regions that are each interconnectable with a corresponding connector region of an adjacent winding when the tape is helically wound to provide a flexible pipe body layer; and

helically winding the tape around an underlying substantially tubular underlayer.

Aptly, the method further comprises providing the tape by supplying preformed tape at a winding station of a manufacturing line. Aptly, the method further comprises the steps of:

providing the tape by extruding polymer at an extrusion station of a manufacturing line;

simultaneously providing one or more inserts at the extrusion station; and

embedding each insert in the extruded polymer as a tape winding is extruded.

Aptly, the method further comprises subsequently curing the extruded material subsequent to the material being wound.

According to a seventh aspect of the present invention there is provided apparatus constructed and arranged substantially as herein described with reference to the accompanying drawings. According to an eighth aspect of the present invention there is provided a method substantially as herein described with reference to the accompanying drawings. Certain embodiments of the present invention enable interlocking of adjacent windings of a helically wound composite element by using an embedded metallic or polymeric clip or spiral spring mechanism to interlock with an equivalent opposing mechanism projecting from an adjacent composite winding. This enables a main body part of a winding to have certain characteristics (for example making it ideal for resisting crush forces) whilst an embedded element in the main body part is manufactured from a different material which can be readily formed into a structure which can provide strong interconnection between adjacent windings.

Certain embodiments of the present invention provide an armour layer by winding a tape which itself has an innate helical shape around an underlying layer. This helps produce an armour layer which, in a non-flexed state, has little inbuilt stresses which would otherwise reduce an overall strength provided by the armour layer.

Certain embodiments of the present invention utilise a physical bonding methodology to secure one or more pre-formed metallic or polymeric strips through and to a composite body part so that the inserted strip/s protrude from either side of the body of the composite body to enable interconnection between adjacent windings.

Certain embodiments of the present invention provide flexible pipe body made by winding a tape which includes at least one insert embedded in and at least partially extending from a body of the tape. Embedding the insert in the main body of the tape ensures the parts do not become detached and thus helps ensure tape windings do not unduly separate.

Certain embodiments of the present invention provide an insert which can be embedded in a composite body to create a tape suitable for winding around an underlying layer to form an armour layer of a segment of flexible pipe body.

Certain embodiments of the present invention provide an elongate tape for forming a layer of interlocked windings. In the tape an insert member is embedded in a body portion so that parts of the insert protrude from the body. These protruding parts interconnect with corresponding parts of an insert in an adjacent winding when the tape is wound helically around an underlying layer to form an armour layer of flexible pipe body. The body portion can optionally be a composite with a matrix material main body part and reinforcing filaments. This enables density of the matrix and/or filaments to be selected where desired across a cross-sectional profile of the tape according to the stresses and strains predicted to be experienced by the tape in use. Alternatively the body portion can be formed from a single material such as a polymer or metal or the like. If formed from metal, the body is made in multiple parts and secured together sandwiching the insert therebetween.

Embodiments of the present invention will now be described hereinafter, by way of example only, with reference to the accompanying drawings in which:

Figure 1 illustrates flexible pipe body;

Figure 2 illustrates a riser, flowline and jumper; Figure 3 illustrates a cross-sectional profile of a pressure armour tape showing parts of two adjacent windings interlocked;

Figure 4 illustrates an insert which can be embedded in a body of a tape; Figure 5 illustrates how reinforcing fibres can be included in the body of a tape to improve crush resistance or other such performance parameters;

Figure 6 shows alternative cross-sections for interlocked tape windings including alternative body and insert shapes;

Figure 7 illustrates a cross section of interlocked tape windings incorporating multiple inserts in the tape;

Figure 8 illustrates still further alternative cross-sectional profiles for wound tapes;

Figure 9 illustrates spiral-type connectors being interconnected; Figure 10 illustrates unfurling a connector; and Figure 1 1 illustrates windings and a manipulator. In the drawings like reference numerals refer to like parts.

Throughout this description, reference will be made to a flexible pipe. It will be understood that a flexible pipe is an assembly of a portion of pipe body and one or more end fittings in each of which a respective end of the pipe body is terminated. Figure 1 illustrates how a portion of pipe body 100 (referred to as a segment) is formed from a combination of layered materials that form a pressure-containing conduit. Although a number of particular layers are illustrated in Figure 1 , it is to be understood that the present invention is broadly applicable to coaxial pipe body structures including one or more layers manufactured from a variety of possible materials. For example, the pipe body may be formed from metallic layers, composite layers, or a combination of different materials. It is to be further noted that the layer thicknesses are shown for illustrative purposes only.

As illustrated in Figure 1 , pipe body includes an optional innermost carcass layer 101 . The carcass provides an interlocked construction that can be used as the innermost layer to prevent, totally or partially, collapse of an internal pressure sheath 102 due to pipe decompression, external pressure, and/or tensile armour pressure and mechanical crushing loads. The carcass layer may be a metallic layer, formed from carbon steel or the like, for example. The carcass layer may also be formed from composite, polymer, or other material, or a combination of materials. It will be appreciated that certain embodiments of the present invention are applicable to 'smooth bore' operations (i.e. without a carcass) as well as such 'rough bore' applications (with a carcass).

The internal pressure sheath 102 acts as a fluid retaining layer and comprises a polymer layer that ensures internal fluid integrity. It is to be understood that this layer may itself comprise a number of sub-layers. It will be appreciated that when the optional carcass layer is utilised the internal pressure sheath may be referred to by those skilled in the art as a barrier layer. In operation without such a carcass the internal pressure sheath may be referred to as a liner.

The pressure armour layer 103 is a structural layer with elements having a lay angle close to 90 ° that increases the resistance of the flexible pipe to internal and external pressure and mechanical crushing loads. The layer also structurally supports the internal pressure sheath, and is an interlocked construction of wires wound with a lay angle close to 90 °. The flexible pipe body also includes an optional first tensile armour layer 105 and optional second tensile armour layer 106. Each tensile armour layer is used to sustain tensile loads and internal pressure. The tensile armour layer may be formed from a plurality of metallic wires (to impart strength to the layer) that are located over an inner layer and are helically wound along the length of the pipe at a lay angle typically between about 10° to 55°. The tensile armour layers may be counter-wound in pairs. The tensile armour layers may be metallic layers, formed from carbon steel, for example. The tensile armour layers may also be formed from composite, polymer, or other material, or a combination of materials. The flexible pipe body shown also includes optional layers 104 of tape which each help contain underlying layers and may act as a sacrificial wear layer to help prevent abrasion between adjacent layers.

The flexible pipe body also includes optional layers of insulation 107 and an outer sheath 108, which comprises a polymer layer used to help protect the pipe against penetration of seawater and other external environments, corrosion, abrasion and mechanical damage.

Each flexible pipe thus comprises at least one segment of pipe body 100 together with an end fitting located at at least one end of the flexible pipe. An end fitting provides a mechanical device which forms the transition between the flexible pipe body and a connector. The different pipe layers as shown, for example, in Figure 1 , are terminated in the end fitting in such a way as to transfer the load between the flexible pipe and the connector. Figure 2 illustrates a riser assembly 200 suitable for transporting production fluids such as oil and/or gas and/or water from a subsea location 201 to a floating facility 202. For example, in Figure 2 the subsea location 201 includes an end of a subsea flow line. The flexible flow line 205 comprises a flexible pipe, wholly or in part, resting on the sea floor 204 or buried below the sea floor and used in a static application. The floating facility may be provided by a platform and/or buoy or, as illustrated in Figure 2, a ship. The riser assembly 200 is provided as a flexible riser, that is to say a flexible pipe 203 connecting the ship to the sea floor installation. The flexible pipeline may be formed from a single segment or multiple segments of flexible pipe body with end fittings connected end-to-end. It will be appreciated that there are different types of riser, as is well-known by those skilled in the art. Certain embodiments of the present invention may be used with any type of riser, such as a freely suspended riser (free, catenary riser), a riser restrained to some extent (buoys, chains) or totally restrained riser. Certain other embodiments of the present invention can be used as flowlines or jumpers or the like. Figure 3 illustrates two adjacent windings of the pressure armour layer 103 in more detail. It is to be noted that certain embodiments of the present invention are not restricted to the provision of a pressure armour layer 103 in the particular location previously described, but are more generally applicable to wherever a layer having a substantially tubular cross- section is to be formed. As illustrated in Figure 3, the tape 300 is wound helically (partially shown in Figure 3). The tape 300 has a main elongate body part 310 in which an insert 320 is embedded. The body part is formed from a polymer material such as polyethylene, polyvinyl chloride, polyamide, polyether-ether-ketone, polyvinylidene fluoride, thermoplastic elastomer, perfluoroalkoxy polymer, or cross-linked, filled or modified alloys of these materials. Filler materials may include compounds of silicon, zinc, iron, aluminium or titanium for the purpose of strengthening the polymer or providing an active reactant within the polymer to react with other chemicals which may be in the pipe annulus. The insert 320 extends continuously along the length of the tape 300. Optionally as an alternative (not shown) the insert comprises multiple separate inserts arranged at predetermined locations along the length of the tape. Optionally, as discussed in more detail below the insert may in fact comprise multiple elongate elements that each extend along the whole length of the tape body. A tape winding 33d is a loop of the tape wrapped around an underlying layer so as to form an arcuate, radially outermost, surface 335i which is substantially smooth and a radially innermost surface 340i which is likewise substantially smooth and arcuate. Adjacent windings 330 _{1 5} 330 ₂ are interlocked. That is to say, adjacent windings are restricted from being unduly separated or moved apart because a first connector 350 which projects from a first side of a winding is interconnected with a complementary further connector 360 which projects from an opposite side of the tape in an adjacent winding. The two connectors complement each other and connect together where adjacent windings face each other. In the embodiment shown in Figure 3 the body part 310 of a tape is substantially l-shaped with a first recessed region 370 extending along a length of the tape on the left hand side of the main body as shown in Figure 3 and an opposed recess 375 extending longitudinally along the length of the tape on an opposed side of the tape. Where a right hand side recessed region 375i of a first winding 335i faces a left hand side recess 370 ₂ of an adjacent winding 330 ₂ , an intermediate space 380 is provided between adjacent windings where the complementary connectors meet and interconnect to prevent separation of windings once the layer 103 has been formed.

Figure 4 illustrates an insert 320 which can be embedded in a body of the tape according to the embodiment of the present invention illustrated in Figure 3. As illustrated in Figure 4, the insert 320 is formed from a sheet of suitable material such as stainless steel, carbon steel or the like which is formed into a substantially flat centre 410 which extends in a spiral form towards a first edge 420 of the insert. Other shapes as well as manufacturing precursors are of course possible according to certain other embodiments of the present invention. A further edge 430 of the insert is also spirally formed. At one side of the insert (corresponding to the left hand side as shown in Figure 4) the edge 420 of the insert forms a first connector 350 of a tape winding. The remaining edge 430 (shown on the right hand side in Figure 4) forms a further connector. As illustrated in Figure 4, the insert is a single elongate unitary body (although as previously mentioned multiple separate elongate unitary bodies could be utilised according to certain other embodiments of the present invention). A row of holes 440 are formed in the insert extending along a length of the insert. These holes act as securing elements to help secure the insert in place at a desired location within the body of the tape. Aptly, each securing element is a throughhole as illustrated in Figure 4. Alternatively, a securing element could be a recessed region or a protruding region or a combination of types.

The spiral spring insert 320 may take the form of a bi-stable composite material which is stable in two opposing orientations. Such materials are well known and their use according to certain embodiments of the present invention is advantageous as they readily return to each of their preferred orientations on bending, optimising both the manufacturing operations and providing the required spiral spring mechanism.

Figure 5 illustrates an alternative embodiment of the present invention in many ways similar to that shown in Figure 3. More particularly, Figure 5 illustrates just the cross-section of two adjacent windings used to form an armour wire layer 103 or the like. As illustrated in Figure 5, the tape which is wound helically to form the layer has a body 510 which is substantially I- shaped. Unlike the embodiment described with respect to Figure 3, the main body part 510 of the tape has a composite structure. That is to say, the body is formed from a matrix or substrate material 520 in which multiple reinforcing fibres 530 are embedded. The fibres 530 behave as reinforcing filament elements and, as illustrated in Figure 5, are aligned more or less in parallel extending along a common axis associated with the elongate length of the tape. It will be appreciated that alternatively reinforcing filaments could be added to a matrix body in a random fashion to create a composite body. Aptly, as illustrated in Figure 5, a density of the fibres is generally constant across the whole area of the cross-section of the tape. Alternatively, it will be understood that a density of the fibres may be selected to be greater in selected regions of the tape body. For example, a density of the fibres may be greater near the central region of the body where the embedded insert is located. This will help fix the insert in position and avoid any risk of the insert being torn out of the body in use. Alternatively and/or additionally a density of the fibres may be higher close to the tips of the body which form the abutment surfaces 385. This helps avoid degradation of the body in use as adjacent windings are constantly urged against each other as a flexible pipe including a layer formed from such windings flexes. Alternatively and/or additionally a density of the fibres may be higher close to the lower face of the elongate tape 540 where hoop stresses in the tape may be higher when the pipe is pressurised, in order to better support the underlying barrier layer. Optionally fibres formed from different materials can be used in predetermined locations to help optimise performance.

Figure 6 helps illustrate alternative embodiments of the present invention based generally upon the concept of having a body of an elongate tape which has a substantially rectangular structure. For example, as illustrated in Figure 6A a tape 600 has a main elongate body part 610 in which an insert 320 of the type illustrated in Figures 3 and 4 is embedded. The tape body part 610 has a lower substantially smooth surface 620 and an upper substantially smooth surface 630 which is disposed in a spaced apart, substantially parallel, relationship to the lower surface 620. A substantially flat first edge 640 of the body 610 extends between the lower surface 620 and upper surface 630. A further substantially smooth edge 650 is spaced apart from, and substantially parallel with, the first edge 640 and likewise extends between the lower surface 620 and upper surface 630. In use compressive forces squeeze the upper surface 630 towards the lower surface 620. The body 610 formed from the matrix material 660 and reinforcing fibres 670 is formed of materials so as to be strong resisting such compressive forces. As a flexible pipe incorporating a layer formed from interlocked windings flexes, the adjacent windings are repeatedly urged apart or together and the interconnected connectors formed from the insert/s helps avoid undue separation (either too close or too far apart).

As illustrated in Figure 6A the left hand side connector 350 extends in a spiral shape to an end. Likewise a left hand side connector 360 of the insert extends to a further end of the insert body. It will be appreciated that the protruding connectors of adjacent windings interlock in an intermediate region 680 between adjacent windings of the tape. In this embodiment the insert is sufficiently strong to not only restrict adjacent windings from becoming separated (that is to say moved too far apart) but also to prevent undue clashing together of adjacent windings. That is to say the interconnected connectors act as spacers between windings to set adjacent windings apart by a predetermined and desired distance.

Figure 6B illustrates an alternative embodiment in which the main body 610 of the tape is in many respects similar to that shown in Figure 6A. However the insert 685 illustrated in Figure 6B has a different cross section to the previously described embodiments. It will be appreciated that inserts having any suitable cross section which allows interlocking and embedding in a main body part of a tape can be adopted according to certain embodiments of the present invention. As illustrated in Figure 6B the insert 685 has a substantially flat central region 686 with through holes 687 periodically spaced along its length. A first edge 688 of the insert forms a hook like region 689 protruding from a respective first side 640 of the main tape body. An opposite edge 690 of the insert provides a valley-like region 691 which interlocks with the hook like region 689 of a projecting insert from adjacent winding. The hook and valley regions interlock so as to avoid undue separation of adjacent windings. The insert body has sufficient strength so that if the adjacent windings are urged together in use the protruding parts of the insert prevent clashing together of the body of the tape. Having a substantially flat abutment surface 692 at respective ends of the connectors helps space adjacent windings apart by a desired distance.

Figure 7 illustrates an alternative embodiment of the present invention in which a tape 700 is formed from a substantially rectangular shaped main body part 710. The tape body part 710 has a lower substantially smooth surface 720 and an upper substantially smooth surface 730 which is disposed in a spaced apart, substantially parallel, relationship to the lower surface 720. A substantially flat first edge 740 of the body 710 extends between the lower surface 720 and the upper surface 730. A further substantially smooth edge 750 is spaced apart from, and substantially parallel with, the first edge 740 and likewise extends between the lower surface 720 and the upper surface 730. The body 710 is formed from a matrix material 760 and reinforcing fibres 770.

The interconnection of adjacent windings of the tape shown in Figure 7 is achieved by virtue of multiple inserts embedded along the length of the tape. In the embodiment shown in Figure 7 each tape has two inserts although it will be appreciated that certain embodiments of the present invention can optionally be formed using one insert or two inserts or three inserts or four inserts or more. As shown in Figure 7 a first insert 780 extends from a central region 785 of the tape body 710 and includes a first end 786 proximate to the central main body region and a further end 787 which protrudes from the edge 740 of the tape. The end 787 of the insert which protrudes from the tape forms a hook or claw like connector. The embedded end 786 of the first insert 780 is terminated in a dogleg region so as to assist in ensuring that the insert is not torn out of the body of the tape in use. Other bends or projections or recesses or openings could of course be utilised as securing elements to help prevent such removal. As illustrated in Figure 7 a second insert 790 extends from the opposed side 750 of the tape. This second insert 790 also has an end 786 embedded in the central region 785 of the main body of the tape. A further edge 797 is bent into a valley or recessed region to accept a hooked region 787 from an adjacent winding in use. In this way when adjacent windings of the tape are wound next to each other to form a layer adjacent windings will not become unduly separated. Aptly as per the embodiment illustrated in Figure 6B the hook and valley regions can include an abutment surface which helps space adjacent windings apart by a predetermined distance in use.

Figure 8 illustrates still further embodiments of the present invention. In the embodiment illustrated in Figure 8A an elongate tape 800 has a substantially rectangular body part formed as a composite including a matrix in which reinforcing fibres are embedded. A single insert 820 includes a first connector portion 830 extending from a first edge 835 of the tape body 810 and a further connector 840 extending from a further opposed edge 845. Rather than have a flat central region the insert 820 illustrated in Figure 8A has a central main body 850 with a central bore 855 extending there through as a through hole.

Figure 8B illustrates an alternative embodiment to that shown in Figure 8A in which the tape 860 has a generally l-shaped body 870 formed as a composite with a matrix material and embedded reinforcing fibres. An insert 880 in many ways similar to that shown in Figure 8A is embedded in the l-shaped body.

Figure 9 illustrates how the spiral-type connectors of the tapes and windings illustrated in Figures 3 to 6A can be unfurled and subsequently interconnected. In more detail Figure 9 illustrates a longitudinal section through a pipe structure during manufacture. A sequence of two wraps of a composite tape 900 are illustrated as already having been applied onto an underlying layer 102 of the pipe 100. It will be appreciated that windings can be interlocked according to certain embodiments of the present invention and applied over any underlying cylindrical structure. As illustrated in Figure 9 a third wrap 905 ₃ of the tape 900 is being fed in the direction A illustrated by the arrow. A manipulator 920 is used to unfurl a right hand side (as shown in Figure 9) connector of a immediately preceding winding 905 ₂ whilst the new winding 905 ₃ is moved towards the pipe 100. Simultaneously the manipulator 920 unfurls a corresponding connector on the left hand side (as shown in Figure 9) of the incoming winding 905 ₃ . The manipulator 920 includes two arms 930 (one illustrated in Figure 9) which unfurls a spiral-like connector of an already wound winding 905 ₂ and two arms 940 (one shown in Figure 9) which unfurl a spiral-like connector of an incoming winding 905 _3.

Figure 10 illustrates a release arm 930 _r and unfurling arm 930 _u of the manipulator 920 illustrated in Figure 10 in more detail. It will be appreciated that a single arm could be utilised to both unfurl and then release an incoming winding according to certain embodiments of the present invention. Alternatively, two, three, four or more arms could be utilised. Alternatively a single elongate unfurling surface including a pointed nose, cylindrical body and end may be used. Such an element may be supported by one or more arms or other such support structures. As illustrated in Figure 10 each arm 930 includes an arm body 1000 which bends in a dogleg into an enlarged cone-like end 1010. The cone-like end 1010 has a substantially frusto-conical outer surface having a leading apex end 1030 forming a nose and a wider end 1040 towards a release end. Each arm thus comprises a conical end to secure and pull and elastically uncurl the spiral interlock unwinding it into an unfurled/open sheet structure 1050. This is in preparation for a connector of the adjacent tape to be linked into the spiral. Referring again to Figure 9 corresponding arms are located extending from an alternative end of the manipulator 920 to unfurl the cooperating spiral-like connector into a sheet-like part. It will be appreciated that the two arms 930 _r , 930 _u shown in Figure 10 are connected to a common manipulator 920. However adjacent arms can of course be connected to separate components radially spaced around the circumference of the pipe or longitudinally along the path of the composite tape according to certain other embodiments of the present invention. The arms at each end of the manipulator, which perform the function of unfurling and then releasing the spiral interlocked connecting elements, are positioned in such a way as to perform their function of opening up opposing spirals substantially simultaneously so that when an opened spiral exits from the arms the natural elasticity of the material of the connector ensures that the connectors snap back and revert to their spiral form. However as they do so the two spirals wind around each other in an entwined interconnecting manner to create a desired interlock. It is to be noted that the process of this interlocking also helps pull the tape into alignment with other tapes already on the pipe providing a desired amount of gap between the windings once the tape is in position on the underlying layer of the pipe. The arms move so as to spiral around the pipe (as illustrated by the arrows B shown in Figure 9) in order to provide and guide the tape around the pipe.

Figure 1 1 helps illustrate, via another perspective view, a tape 900 being wrapped around an outer surface of an underlying layer of a pipe 100. As illustrated in Figure 1 1 the manipulator is a unitary body 1 100 having a hollowed out centre 1 1 10. The arms 930 used to unfurl a spiral-like connector of an already wound and immediately preceding winding are located on an end of an extension 1 120 of the manipulator 920. Likewise the arms 940 used to unfurl a spiral-like connector of an incoming winding are located at an end of a further extension 1 130 which extends from a remaining end of the manipulator. As previously mentioned multiple separate manipulators may be utilised to support the arms according to certain embodiments of the present invention. Likewise the body 1 100 of the manipulator 920 may be formed of many parts and have many different shapes. Figure 1 1 thus illustrates only one tool may be used to support arms used to unfurl the spiral interlocks attached at opposing positions around the tool. The tool 920 also encircles an incoming tape so that the tape passes through a hole in the tool and as it does so the arms attached to the tool open up the spiral interconnectors and guide them into an interlock (hidden from view in Figure 1 1 ). This occurs as the tape wraps down next to a tape winding already on the pipe 100. Aptly the tool/manipulator passes around the pipe (or the pipe turns with respect to the tool) in order to achieve suitable wrapping of the tape. Certain embodiments of the present invention have been described herein above with reference to a elongate body having various cross sections in which one or more inserts are embedded with the inserts at least partially protruding from an edge or surface of the tape body so as to interlock adjacent windings in use. In forming the tapes themselves it will be appreciated that a broad variety of conventional manufacturing techniques can be utilised. Aptly the tape is manufactured prior to winding the tape around an underlying layer to form a layer in a flexible pipe. The tape is manufactured and thereafter stored until the flexible pipe is manufactured.

Alternatively according to certain embodiments of the present invention the tape may optionally be manufactured on site as the flexible pipe itself is manufactured. For example US8066922 describes a method and device for producing a profiled element. Such techniques can be utilised according to certain embodiments of the present invention with separate inserts and optionally reinforcing strands (if a composite body is used) being arranged at the manufacturing station with the extruded tape and insert being provided substantially simultaneously as it is wound.

According to certain embodiments of the present invention the method and device for manufacturing a plastic profile disclosed in US8066922 can be utilised to produce a tape having an innate helical shape. As such the produced tape can be wound around an underlying layer to form a layer in a pipe like structure having very little residual stresses.

Certain embodiments of the present invention thus enable the composite body of a tape to be manufactured around an insert which acts as our connector element (or connector elements) as the tape itself is manufactured. Various interlocking mechanisms such as a spiral or hook and valley arrangement can be formed on ends of the insert/s.

Certain embodiments of the present invention secure an insert in a tape body using a variety of different techniques such as a physical or chemical bonding or combination of physical and chemical bonding systems. Aptly the insert is bonded via an adhesive into the body of the tape. Aptly the insert/s is bonded polymerically in the body of the tape. Aptly in order to promote bonding the insert/s is coated prior to embedding in a tape body. This helps promote adhesion to the matrix material of the composite armouring structural element or within the non-composite base body of the tape.

Certain embodiments of the present invention provide a composite tape which can be made by curved pultrusion or alternatively part cured prior to forming onto a pipe and then being fully cured on the pipe to reduce or eliminate residual stresses in the composite. The shape of the composite tape can optionally be an I-beam, square, rectangular, U-shaped, inverted T-shaped, trapezoidal, elliptical or the like. Aptly as previously described the embedded insert can be positioned through a central region of the tape although according to certain other embodiments of the present invention the insert may be located in other positions for example towards a top (radially outermost in use) surface or a bottom (radially innermost in use) part of the tape body or a combination of these.

Optionally and/or additionally the composite tape may be located in the pipe structure on an additional layer of pipe - another tape layer or polymer layer for example - which lies circumferentially between the barrier layer and the composite tape layer. This underlying tape may itself comprise metal or composite materials and may be designed to bridge the gaps between the composite tape windings so that the underlying barrier polymer does not extrude or creep under pressure into those gaps. Recesses may also be introduced in the lower surfaces of the composite tape to receive upsets in the underlying tape layer, these upsets can then act to locate the composite tape with respect to the underlying tape. Aptly this underlying tape layer can be applied at angles of between 5 degrees and 95 degrees to the axis of the pipe, depending on the material and design of the underlying tape and the interaction of it with the composite tape (if it is desired that it locates the composite tape). Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of them mean "including but not limited to" and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of the features and/or steps are mutually exclusive. The invention is not restricted to any details of any foregoing embodiments. The invention extends to any novel one, or novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.