Flexible pipe end fitting

Abstract

An end-fitting for joining to a pipe body, a flexible pipe including such an end-fitting and a pipe body, and a method of assembling a flexible pipe are disclosed. The end-fitting comprises: a sleeve partially insertable radially inwardly of a polymer layer of the pipe body; and a polymer collar for receiving the polymer layer of the pipe body, the polymer collar disposed radially outwardly of the sleeve, and configured to be welded to the polymer layer of the pipe body. The flexible pipe comprises: a pipe body comprising a polymer layer; and an end-fitting comprising: a sleeve partially inserted radially inwardly of the polymer layer of the pipe body; and a polymer collar for receiving the polymer layer of the pipe body, the polymer collar disposed radially outwardly of the sleeve, and configured to be welded to the polymer layer of the pipe body.

Description

[0001] FLEXIBLE PIPE END FITTING

[0002] The present invention relates to a flexible pipe sealing. In particular, but not exclusively, the present invention relates to an end-fitting for joining to a pipe body, a flexible pipe including such an end-fitting and a pipe body, and a method of assembling a flexible pipe.

[0003] 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 (which may be deep underwater) to a sea level location. The pipe may have an internal diameter of typically up to around 0.6 metres (e.g., diameters may range from 0.05 m up to 0.6 m). Flexible pipe is generally formed as an assembly of a flexible pipe body and one or more end-fittings. The pipe body is typically formed as a combination of layered materials that form a pressure-containing conduit. The pipe structure allows large deflections without causing bending stresses that impair the pipe’s functionality over its lifetime. The pipe body is generally built up as a combined structure including polymer, and / or metallic, and / or composite layers. For example, a pipe body may include polymer and metal layers, polymer and composite layers, or polymer, metal and composite layers.

[0004] API Recommended Practice 17B provides guidelines for the design, analysis, manufacture, testing, installation, and operation of flexible pipes and flexible pipe systems for onshore, subsea and marine applications, and API Specification 17J titled “Specification for Unbonded Flexible Pipe” defines the technical requirements for safe, dimensionally and functionally interchangeable flexible pipes that are designed and manufactured to uniform standards and criteria.

[0005] Unbonded flexible pipe has been used for deep-water (less than 3,300 feet (1 ,005.84 metres)) and ultra deep-water (greater than 3,300 feet) developments. It is the increasing demand for oil which is causing exploration to occur at greater and greater depths where environmental factors are more extreme. For example, in such deep and ultra deep-water environments, ocean floor temperature increases the risk of production fluids cooling to a temperature that may lead to pipe blockage. Increased depths also increase the pressure associated with the environment in which the flexible pipe must operate. For example, a flexible pipe may be required to operate with external pressures ranging from 0.1 MPa to 30 MPa acting on the pipe. Equally, transporting oil, gas or water may well give rise to high pressures acting on the flexible pipe from within, for example, with internal pressures ranging from 0 MPa to 140 MPa from bore fluid acting on the pipe. As a result, the need for high levels of performance from the layers of the flexible pipe body is increased.

[0006] 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. Fig. 1 illustrates how pipe body 100 is formed in accordance with an embodiment from a combination of layered materials that form a pressure-containing conduit. Although a number of particular layers are illustrated in Fig. 1 , it is to be understood that the pipe body is broadly applicable to coaxial structures including two or more layers manufactured from a variety of possible materials. For example, the pipe body may be formed from polymer layers, 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 used herein, the term “composite” is used to broadly refer to a material that is formed from two or more different materials, for example a material formed from a matrix material and reinforcement fibres.

[0007] As illustrated in Fig. 1 , a 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 tensile armour pressure and mechanical crushing loads. The carcass layer is often a metallic layer, formed from stainless steel, for example. The carcass layer could also be formed from composite, polymer, or other material, or a combination of materials. It will be appreciated that certain embodiments are applicable to ‘smooth bore’ operations (i.e., without a carcass layer) as well as such ‘rough bore’ applications (i.e., with a carcass layer).

[0008] The internal pressure sheath 102 acts as a fluid retaining layer and includes a polymer layer that ensures internal fluid integrity. It is to be understood that this layer may itself include a number of sub-layers. It will be appreciated that, when the optional carcass layer is utilised, the internal pressure sheath is often referred to by those skilled in the art as a barrier layer. In operation, without such a carcass (so-called smooth bore operation), the internal pressure sheath may be referred to as a liner.

[0009] An optional pressure armour layer 103 is a structural layer 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 typically may be formed from an interlocked construction of wires wound with a lay angle close to 90°. The pressure armour layer is often a metallic layer, formed from carbon steel, for example. The pressure armour layer could also be formed from composite, polymer, or other material, or a combination of materials.

[0010] 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 is often formed from a plurality of 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 are often counter wound in pairs. The tensile armour layers are often metallic layers, formed from carbon steel, for example. The tensile armour layers could also be formed from composite, polymer, or other material, or a combination of materials.

[0011] The flexible pipe body shown also includes optional layers of tape 104 which help contain underlying layers and to some extent prevent abrasion between adjacent layers. The tape layer may be a polymer or composite or a combination of materials.

[0012] The flexible pipe body also typically includes optional layers of insulation 107. The pipe body includes an outer sheath 108, which includes a polymer layer used to protect the pipe against penetration of seawater and other external environments, corrosion, abrasion and mechanical damage.

[0013] Each flexible pipe includes at least one portion, sometimes referred to as a segment or section 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 Fig. 1 are terminated in the end-fitting in such a way as to transfer the load between the flexible pipe and the connector.

[0014] The end-fittings of a flexible pipe may be used for connecting segments of flexible pipe body together or for connecting them to terminal equipment such as a rigid sub-sea structures or floating facilities. As such, amongst other varied uses, flexible pipe can be used to provide a riser assembly for transporting fluids from a sub-sea flow line to a floating structure. In such a riser assembly, a first segment of flexible pipe may be connected to one or more further segments of flexible pipe. Each segment of flexible pipe includes at least one end-fitting.

[0015] Fig. 2 illustrates a riser assembly 200 suitable for transporting production fluid such as oil and / or gas and / or water from a sub-sea location 201 to a floating facility. For example, in Fig. 2, the sub-sea location 201 includes a sub-sea flow line. The flexible flow line 205 includes 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 Fig. 2, a ship 200. 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 pipe may be in segments of flexible pipe body with connecting end-fittings. It will be appreciated that there are different types of risers, as is well-known by those skilled in the art. Embodiments may be used with any type of riser, such as a freely suspended (free, catenary riser), a riser restrained to some extent (buoys, chains), totally restrained riser or enclosed in a tube (I or J tubes). Fig. 2 also illustrates how portions of flexible pipe can be utilised as a flow line 205 or jumper 206.

[0016] A cross-section of a known end-fitting assembly 300, such as that disclosed in WO2007 / 144552 or EP1867907, is shown in Fig. 3. The end-fitting 300 includes an endfitting body 301 , which includes an internal bore 302 running along its length. The endfitting body is made from steel or other such rigid material. At a first end of the end-fitting body 301 there is defined an open mouth region 303 into which an end of a segment of flexible pipe body 100 is located and then terminated. At a further end of the end-fitting body 301 is a connector 304. This is formed as a substantially disk-like flared region on the end-fitting body. The connector can be connected directly to a matching connector of a further end-fitting body of an adjacent segment of flexible pipe body. This can be done using bolts or some other form of securing mechanism. In such a configuration the endfittings would be located in a back-to-back configuration. Alternatively, the connector 304 may be connected to a floating or stationary structure such as a ship, platform or other such structure. Various layers of flexible pipe body are introduced to the end-fitting assembly, cut to appropriate length, and sealingly engaged with a particular portion of the end-fitting. The end-fitting 300 includes a jacket 307, which is connected to the end-fitting body 301 such that a cavity 313 is formed between the jacket 307 and the end-fitting body 301. Ends 112 of at least one of the various layers of the flexible pipe body 100 are terminated and secured within said cavity 313.

[0017] It is well-known that there are many varied problems associated with the provision of endfittings for ends of a flexible pipe body. The end-fittings must ensure both good fastening and good sealing. There is a need to seal the bore of the flexible pipe body with the bore of the end-fitting. Particular problems occur when the various specific layers of the multi-layer flexible pipe body are terminated. The flexible pipe body may include layers having different material characteristics, for example single polymer layers and / or interlocked metallic layers. The termination of each of these layers in an end-fitting brings with it characteristic problems. For example, a flexible pipe body typically includes a fluidretaining layer formed generally as a polymer sheath or pressure sheath. Such a layer operates as a primary fluid retaining layer. The fluid-retaining layer must connect with an end-fitting, ensuring a full seal to maintain fluid within the bore of the flexible pipe, while parameters such as internal fluid pressure, external hydrostatic pressure and movement from subsea motion make maintaining the seal more difficult.

[0018] It is an aim of the present invention to at least partly mitigate the above-mentioned problems.

[0019] According to a first aspect of the present invention there is provided an end-fitting for joining to a pipe body, wherein the end-fitting comprises: a sleeve partially insertable radially inwardly of a polymer layer of the pipe body; and a polymer collar for receiving the polymer layer of the pipe body, the polymer collar disposed radially outwardly of the sleeve, and configured to be welded to the polymer layer of the pipe body.

[0020] Suitably, the end-fitting comprises an inner collar disposed radially outwardly of the sleeve, wherein the polymer collar is partially disposed between the sleeve and the inner collar.

[0021] Suitably, the end-fitting comprises a jacket disposed radially outwardly of the sleeve, wherein the polymer collar is partially disposed between the sleeve and the jacket. Suitably, the polymer collar is sealingly retained between the sleeve, the jacket, and the inner collar.

[0022] Suitably, the end-fitting comprises: a first recess disposable between the inner collar and the polymer layer of the pipe body; and a first seal configurable to be located in the first recess to prevent fluid ingress between the inner collar and the polymer layer of the pipe body.

[0023] Suitably, the first seal is energised, in use, such that the first seal is swaged against an internal surface of the inner collar.

[0024] Suitably, the end-fitting comprises an outer collar disposed at an end of the inner collar and disposable radially outwardly of the polymer layer of the pipe body, and suitably, the outer collar is configured to energise the first seal, in use.

[0025] Suitably, the end-fitting comprises: a second recess disposed between the inner collar and the jacket; and a second seal configured to be located in the second recess to prevent fluid ingress between the inner collar and the jacket.

[0026] Suitably, the end-fitting comprises: a third recess disposed between the polymer collar and the jacket; and a third seal configured to be located in the third recess to prevent fluid ingress between the polymer collar and the jacket.

[0027] Suitably, an outer surface of the polymer collar comprises a polyamide.

[0028] Suitably, the polymer collar is formed of a polyamide.

[0029] According to a second aspect of the present invention there is provided a flexible pipe, wherein the flexible pipe comprises: a pipe body comprising a polymer layer; and an endfitting comprising: a sleeve partially inserted radially inwardly of the polymer layer of the pipe body; and a polymer collar for receiving the polymer layer of the pipe body, the polymer collar disposed radially outwardly of the sleeve, and configured to be welded to the polymer layer of the pipe body.

[0030] According to a third aspect of the present invention there is provided a method of assembling a flexible pipe, wherein the method comprises: providing a pipe body comprising a polymer layer; providing a sleeve of an end-fitting and partially inserting the sleeve radially inwardly of the polymer layer of the pipe body; and providing a polymer collar of the end-fitting for receiving the polymer layer of the pipe body, disposing the polymer collar radially outwardly of the sleeve, and welding the polymer collar to the polymer layer of the pipe body.

[0031] Suitably, the method comprises providing an inner collar of the end-fitting and disposing the inner collar radially outwardly of the sleeve, wherein the polymer collar is partially disposed between the sleeve and the inner collar.

[0032] Suitably, the method comprises providing a jacket of the end-fitting and disposing the jacket radially outwardly of the sleeve, wherein the polymer collar is partially disposed between the sleeve and the jacket.

[0033] Suitably, the method comprises sealingly retaining the polymer collar between the sleeve, the jacket, and the inner collar.

[0034] Certain embodiments of the invention give the advantage of an improved connection between an end-fitting and a pipe body. Certain embodiments provide an arrangement in which welding of a metallic component of the end-fitting to polymer components of the pipe body is avoided. Certain embodiments give the advantage that metallic components of the end-fitting are provided radially outwardly of a seal between polymer sections of the endfitting and pipe body, such that the seal is protected from failure.

[0035] Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:

[0036] Fig. 1 illustrates an example pipe body;

[0037] Fig. 2 illustrates a riser assembly; Fig. 3 illustrates an example end-fitting;

[0038] Fig. 4 illustrates an end-fitting of a flexible pipe according to an embodiment of the invention;

[0039] Fig. 5 illustrates a further end-fitting of a flexible pipe according to an embodiment of the invention;

[0040] Fig. 6 illustrates a further end-fitting of a flexible pipe according to an embodiment of the invention;

[0041] Fig. 7a illustrates a method of assembling a flexible pipe according to an embodiment of the invention; and

[0042] Fig. 7b illustrates a further method of assembling a flexible pipe according to an embodiment of the invention.

[0043] In the drawings like reference numerals refer to like parts.

[0044] Fig. 4 illustrates an end-fitting 400 of a flexible pipe 1000 according to an embodiment of the invention.

[0045] The end-fitting 400 includes a sleeve 402. The sleeve 402 supports a polymer layer 504 of a pipe body 500 (in this case, a polymer outer sheath), and provides an external surface to dispose a polymer collar 404 of the end-fitting 400 thereon, such that the end-fitting 400 is connectable to the pipe body 500. The sleeve 402 is substantially tubular such that sleeve 402 includes a bore suitable to enable fluid flow therethrough, for example, oil or water. Aptly, the polymer layer 504 is an outer sheath of the pipe body 500.

[0046] The sleeve 402 includes a first section 430a and a second section 430b. The first section 430a is disposed adjacent to the second section 430b. The first section 430a is disposed on a first side of a transverse axis 452, and the second section 430b is disposed on a second side of the transverse axis 452. The sleeve 402 is unitary in construction. The sleeve 402 is formed of metal. In this case, the sleeve 402 is formed of stainless steel. The sleeve 402 may aptly be formed of carbon steel or alloy steel. The sleeve 402 may be formed of aluminium, titanium, or nickel, alloy. The sleeve 402 may optionally be coated with a low friction coating to aid insertion radially beneath a terminal end of the polymer layer 504 of the pipe body 500. The first section 430a is inserted radially inwardly of the polymer layer 504 of the pipe body 500. In this way, the first section 430a provides a transition pathway between the pipe body 500 and the second section 430b of the sleeve 402. The first section 430a has a complimentary profile to an internal surface of the polymer layer 504. Aptly, the internal diameter of the first section 430a is substantially equal to the internal diameter of the polymer layer 504 and the polymer layer 504 must be stretched to receive the sleeve 402, during insertion. Optionally, the polymer layer 504 may be stretched with the application of heat to the terminal end section of the polymer layer 504. Optionally, the external diameter of the first section 430a is substantially equal to the internal diameter of the polymer layer 504, such that the first section 430a and the polymer layer 504 are in contact with one another. The first section 430a supports an internal surface of the polymer layer 504, such that underlying layers of the pipe body 500 pass through the bore of the sleeve 402 and are connected to, or between, other components of the end-fitting 400 (not shown here for simplicity). A first end 444 of the sleeve 402 (more specifically, an end of the first section 430a) includes a tapered portion 454 configured to facilitate inserting the first section 430a radially inwardly of the polymer layer 504.

[0047] The second section 430b extends away from the polymer layer 504. The internal diameter of the second section 430b is equal to the internal diameter of the first section 430a, such that the bore of the sleeve 402 is continuous. The second section 430b is configured to provide support for, and optionally connect to, a polymer collar 404 of the end-fitting 400. In this embodiment, the second section 430b includes a flange 433 configured to limit the insertion of the sleeve 402 within the polymer layer 504, such that the sleeve 402 is partially inserted radially inwardly of the polymer layer 504. The flange 433 has an external diameter larger than the external diameter of any further portion of the second section 430b. The flange 433 abuts the polymer collar 404 of the end-fitting 400, in use, to prevent further insertion of the sleeve 402. More specifically, the flange 433 abuts a second section 432b of the polymer collar 404, in use. Optionally, the polymer collar 404 may be at least partly bonded to the sleeve 402. More specifically, the second section 432b of the polymer collar 404 may be bonded to the second section 430b of the sleeve 402.

[0048] The end-fitting 400 includes a polymer collar 404. The polymer collar 404 is provided radially outwardly of the sleeve 402 and is connectable (e.g., welded) to the polymer layer 504 of the pipe body 500, such that the end-fitting 400 is connected to the pipe body 500. The polymer collar 404 is configured to allow a connection to further components of the end-fitting 400, such that the polymer collar 404 is sealingly retained within the end-fitting 400.

[0049] The polymer collar 404 is disposed radially outwardly of the second section 430b of the sleeve 402. The polymer collar 404 has a complimentary profile to an external surface of the second section 430b of the sleeve 402. The internal diameter of the polymer collar 404 is substantially equal to the external diameter of the second section 430b. The polymer collar 404 is disposed radially adjacent to the second section 430b, such that the polymer collar 404 and the second section 430b are in contact with one another. The polymer collar 404 is formed of a polymer material. In this case, at least an external surface of the polymer collar 404 is formed of a polyamide. Aptly, the polyamide is polyamide 12. Aptly, the polyamide is polyamide 11. Optionally, the material of the polymer collar 404 is a polyethylene, polypropylene, or thermoplastic elastomer.

[0050] The polymer collar 404 includes a first section 432a and a second section 432b. The first section 432a is disposed adjacent to the second section 432b. The first section 432a is disposed on a first side of a transverse axis 456, and the second section 432b is disposed on a second side of the transverse axis 456. The external diameter of the second section 432b is greater than the external diameter of the first section 432a. The second section 432b is configured to allow a connection to a jacket 408 of the end-fitting 400. The sleeve 402 is unitary in construction.

[0051] The polymer collar 404 is connected to the polymer layer 504, such that the pipe body 500 and the end-fitting 400 are connected to one another. Aptly, the polymer collar 404 is welded to the polymer layer 504. More specifically, the first section 432a is welded to the polymer layer 504. The thickness of the first section 432a is substantially equal to the thickness of polymer layer 504 where it over-lies the sleeve 402. Polymer welding may be used to connect the terminal end of the polymer layer 504 with the polymer collar 404 using known techniques, equipment, and a suitable, compatible filler material, providing a full circumference annular connection between the polymer layer 504 and the first section 432a of the polymer collar 404. Aptly, the polymer weld filler material is the same polymer as the polymer layer 504, which is also the same as the polymer of the polymer collar 404. Aptly, the polymers of the polymer layer 504, the weld filler material, and the polymer collar 404 are different but are compatible (i.e., fusible together using known welding techniques). Aptly, the polymer collar 404 may be formed of solid polymer, or may be of a metal, or other rigid material, coated in polymer.

[0052] The end-fitting 400 includes an inner collar 406. The inner collar 406 is provided as part of the end-fitting 400 that lays outwardly of, and thereby protects, polymers sections of the end-fitting 400 and the pipe body 500 (i.e., the first section 432a of the sleeve 402 and the polymer layer 504, and the connection between). The inner collar 406 is further configured to allow a connection to further components of the end-fitting 400.

[0053] The inner collar 406 is partially disposed radially outwardly of first section 432a of the polymer collar 404, such that the polymer collar 404 is disposed between the inner collar 406 and the sleeve 402. The inner collar 406 is further partially disposed radially outwardly of the polymer layer 504, such that the polymer layer 504 is disposed between the inner collar 406 and the sleeve 402. The inner collar 406 is disposed adjacent to the second section 432b of the polymer collar 404. More specifically, a second end 442 of the inner collar 406 is adjacent to the second section 432b of the polymer collar 404.

[0054] The inner collar 406 has a substantially complimentary profile to the external surfaces of the first section 432a of the polymer collar 404 and the polymer layer 504. The internal diameter of the inner collar 406 is substantially equal to the external diameters of the first section 432a and that of the polymer layer 504, where it over-lies the sleeve 402. The inner collar 406 is disposed radially adjacent to the first section 432a and the polymer layer 504, such that the inner collar 406 is in contact with the first section 432a and the polymer layer 504. The inner collar 406 is formed of a metal. In this case, the inner collar 406 is formed of stainless steel. Aptly, the inner collar 406 is made of carbon or alloy steel. Aptly, the inner collar 406 is made of aluminium, or titanium, alloy. Optionally, the inner collar 406 may be at least partly coated with a suitable corrosion protection coating system, such as an epoxy-based coating.

[0055] An internal surface 458 of the inner collar 406 has a tapered section 460. The tapered section 460 tapers from a larger diameter to a smaller diameter in a direction moving away from a first end 440 of the inner collar 406. In other words, the tapered section 460 has a first end 462a at the first end 440 of the inner collar 406, and a second end 462b at a position along the length of the internal surface 458 of the inner collar 406, and the internal diameter at the first end 462a is greater than the internal diameter at the second end 462b. As shown in Fig. 4, the tapered section 460 tapers non-linearly. The tapered section 460 includes a portion that is orientated perpendicular to a longitudinal axis (not shown) of the end-fitting 400. Aptly, the tapered section 460 comprises a sealing surface configured to engage with an opposing sealing surface of a first seal 416 (see also Fig. 5).

[0056] The end-fitting 400 includes a first recess 414. The first recess 414 is configured to receives a first seal 416 of the end-fitting 400, and the first seal 416 is configured to prevent fluid ingress between the inner collar 406 and the polymer layer 504. The first recess 414 is disposed between the inner collar 406 and the polymer layer 504. More specifically, the first recess 414 is disposed between the tapered section 460 and the polymer layer 504, such that the first recess 414 has an at least partly tapered profile. The first recess 414 is annular.

[0057] The end-fitting 400 includes a first seal 416. The first seal 416 is configured to be energised, in use, such that fluid ingress between the inner collar 406 and the polymer layer 504 is prevented. During assembly of the end-fitting 400, the first seal 416 is energised by an outer collar 420 of the end-fitting 400, as described below. Preventing fluid ingress, in this manner, protects the connection between the polymer layer 504 and the polymer collar 404. The first seal 416 is disposed in the first recess 414. The first seal 416 has a complimentary profile to the first recess 414. The first recess 414 has an at least partly tapered profile and the first seal 416 has a complimentary at least partly tapered profile. Aptly, the tapered section of the first seal 416 comprises a sealing surface configured to engage with an opposing sealing surface of the tapered section 460 of the first recess 414 (see also Fig. 5).

[0058] At least a portion of the first seal 416 proximate to the second end 462b of the tapered section 460 is configured to deform radially inwards when the first seal 416 is urged into the recess 414, pushing into an intimate engagement with the polymer layer 504.

[0059] The inner collar 406 includes an end section 436. The end section 436 is configured to allow a connection to a jacket 408 of the end-fitting 400. The end section 436 has a first end 437a disposed at a position along the length of the internal surface 458 of the inner collar 406, and a second end 437b disposed at the second end 442 of the inner collar 406, such that the end section 436 is adjacent to the second section 432b of the polymer collar 404. The external diameter of the end section 436 is optionally larger than any other section of the inner collar 406.

[0060] The end-fitting 400 includes an outer collar 420. The outer collar 420 is configured to energise the first seal 416 disposed in the first recess 414, such that fluid ingress between the inner collar 406 and the polymer layer 504 is prevented, and also the portion of the polymer layer 504 inside the end-fitting 400 (i.e. , the portion beyond the first seal 416) is isolated from forces or stress loading present in the polymer layer 504 outside of the endfitting 400, as a result of tension or bending of the pipe body 500.

[0061] The outer collar 420 is disposed at the first end 440 of the inner collar 406, and radially outwardly of the polymer layer 504. The outer collar 420 has a complimentary profile to the external surface of the polymer layer 504. The internal diameter of the outer collar 420 is substantially equal to the external diameter of the polymer layer 504. The outer collar 420 is disposed radially adjacent to the polymer layer 504 such that the outer collar 420 is in contact with the polymer layer 504. The outer collar 420 is formed of a metal. In this case, the outer collar 420 is formed of stainless steel. Aptly, the outer collar 420 is made of carbon or alloy steel. Aptly, the outer collar 420 is made of aluminium, or titanium, alloy. Optionally, the outer collar 420 may be at least partly coated with a suitable corrosion protection coating system, such as an epoxy-based coating.

[0062] The outer collar 420 is configured to affix to the inner collar 406. In this case, the outer collar 420 is affixed to the inner collar 406 using a plurality of fixings (e.g., a bolt). During joining the outer collar 420 to the inner collar 406, the outer collar 420 moves towards the inner collar 406. The outer collar 420, in turn, applies a pressure to the first seal 416 disposed in the first recess 414, and energises the first seal 416 to move along the first recess 414 and swage against the inner collar 406. More specifically, the first seal 416 swages against the tapered section 460 of the internal surface 458 of the inner collar 406.

[0063] When the first seal 416 is swaged against the inner collar 406, the inner collar 406 deforms the first seal 416. The first seal 416 is deformed such that the first seal 416 is compressed against the polymer layer 504. More specifically, the first seal 416 is compressed against an external surface of the polymer layer 504. Compressing the first seal 416 against the polymer layer 504, in this manner, prevents fluid ingress between the first seal 416 and the polymer layer 504. The end-fitting 400 includes a jacket 408. The jacket 408 is provided as part of the endfitting 400 that lays outwardly of, and thereby protects, polymers sections of the end-fitting 400 (i.e., the second section 432b of the sleeve 402). The jacket 408 is configured to connect to the polymer collar 404 and the inner collar 406, such that the polymer collar 404 is sealingly retained between the jacket 408, the inner collar 406, and the sleeve 402. The jacket 408 is further configured for receiving and enclosing further components of the flexible pipe 1000.

[0064] The jacket 408 is disposed radially outwardly of the polymer collar 404, such that the polymer collar 404 is disposed between the jacket 408 and the sleeve 402. More specifically, the jacket 408 is disposed radially outwardly of the second section 432b of the polymer collar 404. The jacket 408 is disposed adjacent to the inner collar 406. More specifically, the jacket 408 is disposed adjacent to the end section 436 of the inner collar 406.

[0065] It will be understood that other configurations may be conceivable, wherein the jacket 408 is disposed radially outwardly of both the polymer collar 404 and the inner collar 406, with each of the polymer collar 404 and the inner collar 406 featuring a similar outer radial diameter, configured to be similar to an internal diameter of the jacket 408. Further, it will be understood that the jacket 408 may comprise a radially inward pointing flange with which it may interface an end surface region of the first end 437a of the end section 436, distal to the second end 442 of the inner collar 406. The jacket 408 may thereby at least partly enclose the end section 436 of the inner collar 406, and may be affixed to the inner collar 406 using a plurality of fixings (e.g., bolts).

[0066] The jacket 408 is formed of a metal. In this case, the jacket 408 is formed of stainless steel. Aptly, the jacket 408 is made of carbon or alloy steel. Aptly, the jacket 408 is made of aluminium, or titanium, alloy. Optionally, the jacket 408 may be at least partly coated with a suitable corrosion protection coating system, such as an epoxy-based coating.

[0067] The end-fitting 400 includes at least one second recess 410. The second recess 410 is an annular recess configured to receive a second seal 412 of the end-fitting 400, and the second seal 412 is configured to prevent fluid ingress between the jacket 408 and the inner collar 406. The second recess 410 is disposed between the jacket 408 and the inner collar 406. More specifically, the second recess 410 is disposed between the jacket 408 and the end section 436 of the inner collar 406. The end-fitting 400 includes a second seal 412 disposed in the second recess 410. Optionally, the second seal 412 has a complimentary profile to the second recess 410, such that the second seal 412 substantially fills the second recess 410 and fluid ingress between the jacket 408 and the inner collar 406 is prevented. Optionally, the second seal 412 is an O-ring or an API 6A type gasket seal ring, or similar. Optionally, the second recess 410 includes two recesses, and the second seal 412 includes two O-rings receivable in the two recesses. Optionally, a unitary second recess 410 is suitable to receive two or more O-rings in the one recess, which act together to provide a seal.

[0068] The end-fitting 400 includes at least one third recess 424. The third recess 424 is an annular recess configured to receive a third seal 426 of the end-fitting 400, and the third seal 426 is configured to prevent fluid ingress between the jacket 408 and the polymer collar 404. The third recess 424 is disposed between the jacket 408 and the polymer collar 404. More specifically, the third recess 424 is disposed between the jacket 408 and the second section 432b of the polymer collar 404. The end-fitting 400 includes a third seal 426 disposed in the third recess 424. Optionally, the third seal 426 has a complimentary profile to the third recess 424, such that the third seal 426 substantially fills the third recess 424 and fluid ingress between the jacket 408 and the polymer collar 404 is prevented. Optionally, the third seal 426 is an O-ring or an API 6A type gasket seal ring, or similar. Optionally, the third recess 424 includes two recesses, and the third seal 426 includes two O-rings receivable in the two recesses. Optionally, a unitary third recess 424 is suitable to receive two or more O-rings in the one recess, which act together to provide a seal.

[0069] The end-fitting 400 includes a first pressure test port 422 for testing any of: the first seal 416 disposed in the first recess 414, the second seal 412 disposed in the second recess 410, the connection between the polymer collar 404 and the polymer layer 504, and the third seal 426 disposed in the third recess 424. The first pressure test port 422 is disposed on the inner collar 406, and extends through the inner collar 406 to both the second recess 410 and the interface between the inner collar 406 and the polymer collar 404. In use, a fluid is injected through the first pressure test port 422 such that the fluid is distributed along the interfaces between components of the end-fitting 400 and towards the seal and / or connection to be tested. The end-fitting 400 includes a second pressure test port 428 for further testing the third seal 426 disposed in the third recess 424. The second pressure test port 428 is disposed on the jacket 408, and extends through the jacket 408 to the third recess 424. In use, a fluid is injected through the second pressure test port 428 such that the fluid is distributed to the third seal 426 disposed in the third recess 424.

[0070] Fig. 5 illustrates a further end-fitting 600 of a flexible pipe 2000 according to an embodiment of the invention. As stated above, like reference numerals refer to like parts.

[0071] The end-fitting 600 includes a sleeve 402, as described in relation to Fig. 4.

[0072] In this embodiment, the second section 430b of the sleeve 402 is configured to limit the insertion of the sleeve 402 within the polymer layer 504, such that the sleeve 402 is partially inserted radially inwardly of the polymer layer 504. The second section 430b has an external diameter larger than the first section 430b of the sleeve 402. The second section 430b abuts an end of the polymer layer 504, in use, to prevent further insertion of the sleeve 402.

[0073] The end-fitting 600 includes a polymer collar 604. The polymer collar 604 is connectable (e.g., welded) to the polymer layer 504 of the pipe body 500, such that the end-fitting 600 is connected to the pipe body 500. The polymer collar 604 is further configured to allow a connection to both a jacket 608 and an inner collar 606 of the end-fitting 600.

[0074] In this embodiment, the polymer collar 604 is disposed radially outwardly of the polymer layer 504, such that the polymer layer 504 is partially disposed between the polymer collar 604 and the sleeve 402. The polymer collar 604 has a complimentary profile to the external surface of the polymer layer 504. The internal diameter of the polymer collar 604 is substantially equal to the external diameter of the polymer layer 504, where it overlies the sleeve 402. The polymer collar 604 is disposed radially adjacent to the polymer layer 504, such that the polymer collar 604 may be in contact with the polymer layer 504. The polymer collar 604 is formed of a polymer material. In this case, at least an external surface of the polymer collar 604 is formed of a polyamide. Aptly, the polyamide is polyamide 12. Aptly, the polyamide is polyamide 11. Optionally, the material of the polymer collar 604 is a polyethylene, polypropylene, or thermoplastic elastomer. The polymer collar 604 includes an end section 636. The end section 636 is configured to be connected to the polymer layer 504. In this embodiment, the end section 636 has a smaller diameter than any further section along an external surface of the polymer collar 604. The polymer collar 604 is connected to the polymer layer 504, such that the pipe body 500 and the end-fitting 600 are connected to one another. The polymer collar 604 is welded to the pipe body 500. More specifically, the end section 636 of the polymer collar 604 is welded to the polymer layer 504. Optionally, the end section 636 has the same diameter as any further section but is still configured to be connectable (e.g., welded) to the polymer layer 504.

[0075] The end-fitting 600 includes an inner collar 606. The inner collar 606 is provided as part of the end-fitting 600 that lays outwardly of, and thereby protects, polymers sections of the end-fitting 600 and the pipe body 500 (i.e., the end section 636 of the polymer collar 604 and the polymer layer 504, and the connection between). The inner collar 606 is further configured to allow a connection to the polymer collar 604 and an outer collar 420 of the end-fitting 600.

[0076] In this embodiment, the inner collar 606 is partially disposed radially outwardly of the polymer collar 604. More specifically, the inner collar 606 is disposed radially outwardly of the end section 636 of the polymer collar 604, such that the end section 636 is disposed between the inner collar 606 and the polymer layer 504. The inner collar 606 is further partially disposed radially outwardly of the polymer layer 504, such that the polymer layer 504 is disposed between the inner collar 606 and the sleeve 402. The inner collar 606 is disposed adjacent to the polymer collar 604. More specifically, the inner collar 606 is disposed adjacent to a first end 643a of the polymer collar 604.

[0077] The inner collar 606 has a complimentary profile to the external surfaces of the end section 636 of the polymer collar 604 and the polymer layer 504. In this embodiment, the internal diameter of the inner collar 606 is substantially equal to the external diameters of the end section 636 and the polymer layer 504, where it overlies the sleeve 402. The inner collar 606 is disposed radially adjacent to the end section 636 and the polymer layer 504, such that the inner collar 606 is in contact with the end section 636 and the polymer layer 504. The inner collar 606 is formed of a metal. In this case, the inner collar 606 is formed of stainless steel. Aptly, the inner collar 606 is made of carbon or alloy steel. Aptly, the inner collar 606 is made of aluminium, or titanium, alloy. Optionally, the inner collar 606 may be at least partly coated with a suitable corrosion protection coating system, such as an epoxy-based coating.

[0078] The end-fitting 600 includes at least one second recess 610. The second recess 610 is an annular recess configured to receive a second seal 612 of the end-fitting 600, and the second seal 612 is configured to prevent fluid ingress between the polymer collar 604 and the inner collar 606. The second recess 610 is disposed between the polymer collar 604 and the inner collar 606. The end-fitting 600 includes a second seal 612 disposed in the second recess 610. Optionally, the second seal 612 has a complimentary profile to the second recess 610, such that the second seal 612 substantially fills the second recess 610 and fluid ingress between the polymer collar 604 and the inner collar 606 is prevented. Optionally, the second seal 612 is an O-ring or an API 6A type gasket seal ring, or similar. Optionally, the second recess 610 includes two recesses, and the second seal 612 includes two O-rings receivable in the two recesses. Optionally, a unitary second recess 610 is suitable to receive two or more O-rings in the one recess, which act together to provide a seal.

[0079] The inner collar 606 has an internal surface 458 including a tapered section 460, as described in relation to Fig. 4. Similarly, the end-fitting 600 includes a first recess 414 and a first seal 416 disposed in the first recess 414, as described in relation to Fig. 4.

[0080] The end-fitting 600 includes an outer collar 420, as described in relation to Fig. 4.

[0081] The end-fitting 600 includes a jacket 608. The jacket 608 is further configured for receiving and enclosing further components of the flexible pipe 2000.

[0082] In this embodiment, the jacket 608 is partially disposed radially outwardly of the sleeve 402. More specifically, the jacket 608 is disposed radially outwardly of the second section 430b of the sleeve 402. The jacket 608 has a complimentary profile to the external surface of the second section 430b. The internal diameter of the jacket 608 is substantially equal to the external diameter of the second section 430b. The jacket 608 is disposed radially adjacent to the second section 430b, such that the jacket 608 may be in contact with the second section 430b and optionally, radially adjacent to the polymer layer 504. The jacket 608 may be disposed axially adjacent to the polymer collar 604. More specifically, the jacket 608 is disposed adjacent to a second end 643b of the polymer collar 604. The jacket 608 is formed of a metal. In this case, the jacket 408 is formed of stainless steel. Aptly, the jacket 608 is made of carbon or alloy steel. Aptly, the jacket 608 is made of aluminium, or titanium, alloy. Optionally, the jacket 608 may be at least partly coated with a suitable corrosion protection coating system, such as an epoxy-based coating.

[0083] The end-fitting 600 includes a third recess 424 and a third seal 426 disposed in the third recess 424, as described in relation to Fig. 4.

[0084] Fig. 6 illustrates a further end-fitting 700 of a flexible pipe 3000 according to an embodiment of the invention. As stated above, like reference numerals refer to like parts. It will be clear to the skilled person that sub-layers of the pipe body 500 (i.e., those radially inwards of the polymer layer 504) are not shown for simplicity, nor therefore are the terminations and securing of those layers, in a known manner, in the end-fitting 700.

[0085] The end-fitting 700 includes a polymer collar 702. The polymer collar 702 is provided radially outwardly of a polymer layer 504 of a pipe body 500 and is connectable (e.g., welded at a circumferential polymer weld 724) to the polymer layer 504, such that the endfitting 700 is connected to the pipe body 500. The polymer collar 702 allows a connection to an end section 704 of the end-fitting 700.

[0086] The polymer layer 504 is inserted radially inwardly of the polymer collar 702. The polymer layer 504 is inserted until a tapered portion 716, disposed at a first end 712 of the polymer collar 702 is positioned at a desired axial position on the polymer layer 504, or until a tapered start 506 of a first, machined portion 510a of the polymer layer 504 abuts a first end 712 of the polymer collar 702. The tapered start 506 of the first, machined portion 510a of the polymer layer 504 is disposed along a desired length of the polymer layer 504. The tapered start 506 therefore provides a transition pathway between a first, machined portion 510a of the polymer layer 504, that is inserted radially inwardly of the polymer layer 702, and a second, as-extruded portion 510b of the polymer layer 504. In this embodiment, the external diameter of the second portion 510b of the polymer layer 504 is larger than both the external diameter of the first portion 510a of the polymer layer 504, and an internal diameter of the polymer collar 702. The polymer collar 702 has a complimentary profile to an external surface of the first portion 510a of the polymer layer 504. The internal diameter of the polymer collar 702 is substantially equal to the external diameter of the first portion 510a of the polymer layer 504. The polymer collar 702 is disposed radially adjacent to the first portion 510a of the polymer layer 504, such that the polymer collar 702 and the polymer layer 504 are in contact with one another. The polymer collar 702 is formed of a polymer. In this case, the polymer collar 702 is formed of a polyamide. Aptly, the polyamide is polyamide 12. Aptly, the polyamide is polyamide 11. Optionally, the material of the polymer collar 702 is a polyethylene, polypropylene, or a thermoplastic elastomer.

[0087] The polymer collar 702 includes an optional recess 720. The recess 720 may be configured to receive a seal (not shown), and the seal is configured to prevent fluid ingress between the polymer collar 702 and the polymer layer 504. The recess 720 is disposed between the polymer collar 702 and the polymer layer 504, to receive an extended portion of the end section 704.

[0088] The end-fitting 700 may also include a further recess 726 disposed between the end section 704 and the polymer layer 504. The recess 726 is configured to receive a seal 728. The seal 728 has a complimentary profile to the further recess 726, such that the seal 728 substantially fills the further recess 726. Fluid pressure from inside the end-fitting 700 is denied access to between the polymer collar 702 and the polymer layer 504, such that damage to the polymer weld 724 from pressure internal to the end-fitting 700 is prevented.

[0089] The polymer collar 702 is connected to the polymer layer 504, such that the end-fitting 700 and the pipe body 500 are connected to one another. The polymer collar 702 is welded to the polymer layer 504 at circumferential polymer weld 724. More specifically, in this embodiment, a tapered portion 716, disposed at a first end 712 of the polymer collar 702, is welded to the tapered portion 506 of the polymer layer 504 at the polymer weld 724.

[0090] The polymer collar 702 includes a receiving portion 718 for receiving a fixing (not shown) (e.g., a bolt) configured to join the polymer collar 702 to at least an end section 704 of the end-fitting 700. The receiving portion 718 is disposed radially outwardly of the optional recess 720. As shown in Fig. 6, in this case, the receiving portion 718 is disposed at at least two points around the circumference of the polymer collar 702. As such, a plurality of fixings can be used to join the polymer collar 702 with the end section 704.

[0091] The end-fitting 700 includes an end section 704. The end section 704 is configured to maintain the connection (e.g., a weld) between the polymer collar 702 and the polymer layer 504. The end section 704 is further configured to allow a connection to further components of the flexible pipe 3000.

[0092] The end section 704 is disposed at a second end 714 of the polymer collar 702, and proximate to a terminal end 508 of the polymer layer 504. The end section 704 is disposed adjacent to the polymer collar 702 and the polymer layer 504. More specifically, the end section 704 is disposed adjacent to the first portion 510a of the polymer layer 504. The end section 704 is formed of metal. In this case, the end section 704 is formed of stainless steel. Aptly, the end section 704 is made of carbon or alloy steel. Aptly, the end section 704 is made of aluminium, or titanium, alloy. Optionally, the end section 704 may be at least partly coated with a suitable corrosion protection coating system, such as an epoxybased coating.

[0093] The end section 704 includes a receiving portion 722 configured to receive a fixing configured to join the end section 704 and the polymer collar 702. As shown in Fig. 6, in this case, the receiving portion 722 is disposed at at least two points around the circumference of the end section 704. The receiving portion 722 of the end section 704 corresponds to the receiving portion 718 of the polymer collar 702, such that a fixing may be received through both the receiving portion 722 of the end section 704 and the receiving portion 718 of the polymer collar 702.

[0094] Optionally, a sleeve 402 is inserted radially inwards of the terminal end 508 of the polymer layer 504. More specifically, the sleeve 402 is inserted under, and is in contact with, at least part of the first portion 510a, and thereby supports the polymer layer 504 when a further seal 728 is swaged into sealing engagement with the polymer layer 504 at the outside diameter surface of the first portion 510a of the polymer layer 504.

[0095] Fig. 7a illustrates a method 800 of assembling a flexible pipe 1000 according to an embodiment of the invention. The method 800 of assembling a flexible pipe 1000 includes the step 802 of providing a pipe body 500 including a polymer layer 504. The step 802 further includes providing a sleeve 402 of an end-fitting 400 and partially inserting the sleeve 402 radially inwardly of the polymer layer 504.

[0096] The method 800 further includes the step 804 of providing a polymer collar 404 of the endfitting 400. The step 804 further includes disposing the polymer collar 404 radially outwardly of the sleeve 402, and connecting the polymer collar 404 to the pipe body 500. The polymer collar 404 is welded to the polymer layer 504 of the pipe body 500.

[0097] Fig. 7b illustrates a method 850 of assembling a flexible pipe 1000 including an end-fitting 400 and a pipe body 500 according to an embodiment of the invention.

[0098] The method 850 of assembling a flexible pipe 1000 includes the steps 802, 804 of the method 800 of assembling a flexible pipe 1000. The method 850 further includes optional steps 808, 810, 812, 814, 816, 818, 820.

[0099] The method 850 further includes the step 806 of providing an inner collar 406 of the endfitting 400. The step 806 further includes partially disposing the inner collar 406 radially outwardly of the polymer collar 404 and partially disposing the inner collar 406 radially outwardly of the polymer layer 504.

[0100] The method 850 further includes the step 808 of providing a jacket 408 of the end-fitting 400. The method 850 further includes disposing the jacket 408 radially outwardly of the polymer collar 404.

[0101] The method 850 further includes the step 810 of providing a first recess 414 of the endfitting 400 and disposing the first recess 414 between the inner collar 406 and the polymer layer 504. The step 810 further includes providing a second recess 410 of the end-fitting 400 and disposing the second recess 410 between the jacket 408 and the inner collar 406. The step 810 further includes providing a third recess 424 of the end-fitting 400 and disposing the third recess 424 between the jacket 408 and the polymer collar 404. The method 850 further includes the step 812 of providing a first seal 416 of the end-fitting 400 and disposing the first seal 416 in the first recess 414. The step 812 further includes providing a second seal 412 of the end-fitting 400 and disposing the second seal 412 in the second recess 410. The step 812 further includes providing a third seal 426 of the endfitting 400 and disposing the third seal 426 in the third recess 424, such that the polymer collar 404 is sealingly retained between the jacket 408, the inner collar 406, and the sleeve 402.

[0102] The method 850 further includes the step 814 of providing an outer collar 420 of the endfitting 400 and affixing the outer collar 420 to an end of the inner collar 406. The step 814 further includes energising the first seal 416 such that the first seal 416 is swaged against an internal surface 458 of the inner collar 406.

[0103] Various modifications to the detailed arrangements as described above are possible.

[0104] A sealant or an adhesive may be introduced between the first section 430a of the sleeve 402 and the polymer layer 504 of the pipe body 500, such that fluid ingress between the first section 430a and the polymer layer 504 is further prevented.

[0105] The first section 430a of the sleeve 402 may include serrations on an outer surface, such that the first section 430a results in an interference fit with the polymer layer 504. The serrations may include a labyrinth profile to improve the contact stress between the components.

[0106] Instead of the polymer collar 404 being formed of polyamide, the polymer collar 404 may be formed of any material configured to be weldable to the polymer layer 504 of the pipe body 500. Furthermore, the thickness of the first section 432a of the polymer collar 404 may not be substantially equal to the thickness of the polymer layer 504. The first section 432a of the polymer collar 404 may have any thickness such that the polymer collar 404 is weldable to the polymer layer 504. The polymer layer 504 of the pipe body 500 may be an outer sheath, or an outer abrasion or wear layer of pipe body 500. The polymer layer 504 may include multiple layers of the pipe body 500.

[0107] The tapered portion 454 of the first section 430a of the sleeve 402 may be further configured to prevent gap formation between the first section 430a and the polymer layer 504.

[0108] Instead of the first recess 414 and / or the second recess 410 and / or the third recess 424 being annular, the first recess 414 and / or the second recess 410 and / or the third recess 424 may be disposed at at least one point around a circumference of the end-fitting 400.

[0109] The external diameter of the end section 436 of the inner collar 406 may be equal to the external diameter of the further sections of the inner collar 406.

[0110] The external diameter of the second section 432b of the polymer collar 404 may be equal to the external diameter of the first section 432b of the polymer collar 404.

[0111] Instead of partially disposing the inner collar 406 radially outwardly of the polymer collar 404, the step 806 of method 850 may include providing an inner collar 406 of the endfitting 400 at least partly underneath a polymer collar 404, partially disposing the inner collar 406 radially inwardly of the polymer collar 404 and partially disposing the inner collar 406 radially outwardly of the polymer layer 504.

[0112] The precise dimensions of the features of the end-fitting 400, 600, 700 have been described for example only.

[0113] With the above-described arrangement, the polymer layer of the pipe body is connected, for example, welded, to a polymer collar of the end-fitting. That is, a polymer-to-polymer weld can be used. This helps overcome the aforementioned difficulties in connecting the polymer layer to a metallic component of the end-fitting. With the above-described arrangement, the end-fitting is connected to a pipe body using fewer seals that known arrangements. Reducing the number of seals, in this manner, mitigates the adverse affects of polymer creep, typically experienced at deep-water pressures.

[0114] With the above-described arrangement, an inner collar and a jacket of the end-fitting are disposed radially outwardly of both the polymer layer and the polymer collar, and the connection (e.g., a weld) between the polymer layer and the polymer collar. The connection between the polymer collar and the polymer layer is thereby protected from failure, providing an improved connection between the end-fitting and the pipe body.

[0115] It will be clear to a person skilled in the art that features described in relation to any of the embodiments described above can be applicable interchangeably between the different embodiments. The embodiments described above are examples to illustrate various features of the invention.

[0116] 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.

[0117] Features, integers, characteristics, compounds, chemical moieties 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 such features and / or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any 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.

Claims

CLAIMS1. An end-fitting for joining to a pipe body, wherein the end-fitting comprises: a sleeve partially insertable radially inwardly of a polymer layer of the pipe body; and a polymer collar for receiving the polymer layer of the pipe body, the polymer collar disposed radially outwardly of the sleeve, and configured to be welded to the polymer layer of the pipe body.

2. An end-fitting according to claim 1 , wherein the end-fitting comprises an inner collar disposed radially outwardly of the sleeve, wherein the polymer collar is partially disposed between the sleeve and the inner collar.

3. An end-fitting according to claim 2, wherein the end-fitting comprises a jacket disposed radially outwardly of the sleeve, wherein the polymer collar is partially disposed between the sleeve and the jacket.

4. An end-fitting according to claim 3, wherein the polymer collar is sealingly retained between the sleeve, the jacket, and the inner collar.

5. An end-fitting according to claim 4, wherein the end-fitting comprises: a first recess disposable between the inner collar and the polymer layer of the pipe body; and a first seal configurable to be located in the first recess to prevent fluid ingress between the inner collar and the polymer layer of the pipe body.

6. An end-fitting according to claim 5, wherein the first seal is energised, in use, such that the first seal is swaged against an internal surface of the inner collar.

7. An end-fitting according to claim 6, wherein the end-fitting comprises an outer collar disposed at an end of the inner collar and disposable radially outwardly of the polymer layer of the pipe body, wherein the outer collar is configured to energise the first seal, in use.

8. An end-fitting according to any of claims 4 to 7, wherein the end-fitting comprises: a second recess disposed between the inner collar and the jacket; and a second seal configured to be located in the second recess to prevent fluid ingress between the inner collar and the jacket.

9. An end-fitting according to any of claims 4 to 8, wherein the end-fitting comprises: a third recess disposed between the polymer collar and the jacket; and a third seal configured to be located in the third recess to prevent fluid ingress between the polymer collar and the jacket.

10. An end-fitting according to any of the preceding claims, wherein an outer surface of the polymer collar comprises a polyamide.

11. An end-fitting according to any of the preceding claims, wherein the polymer collar is formed of a polyamide.

12. A flexible pipe, wherein the flexible pipe comprises: a pipe body comprising a polymer layer; and an end-fitting comprising: a sleeve partially inserted radially inwardly of the polymer layer of the pipe body; anda polymer collar for receiving the polymer layer of the pipe body, the polymer collar disposed radially outwardly of the sleeve, and configured to be welded to the polymer layer of the pipe body.

13. A method of assembling a flexible pipe, wherein the method comprises: providing a pipe body comprising a polymer layer; providing a sleeve of an end-fitting and partially inserting the sleeve radially inwardly of the polymer layer of the pipe body; and providing a polymer collar of the end-fitting for receiving the polymer layer of the pipe body, disposing the polymer collar radially outwardly of the sleeve, and welding the polymer collar to the polymer layer of the pipe body.

14. A method according to claim 13, wherein the method comprises providing an inner collar of the end-fitting and disposing the inner collar radially outwardly of the sleeve, wherein the polymer collar is partially disposed between the sleeve and the inner collar.

15. A method according to claim 14, wherein the method comprises providing a jacket of the end-fitting and disposing the jacket radially outwardly of the sleeve, wherein the polymer collar is partially disposed between the sleeve and the jacket.

16. A method according to claim 15, wherein the method comprises sealingly retaining the polymer collar between the sleeve, the jacket, and the inner collar.

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