Flexible pipe sealing

Abstract

The disclosure includes a sealing assembly for an end-fitting of a flexible pipe, an end fitting, a flexible pipe, and a method of assembling a flexible pipe. The sealing assembly is disposable between a collar of the end-fitting and a polymer layer of a pipe body of the flexible pipe. The sealing assembly includes: a deformable ring disposable radially outwardly of the polymer layer of the pipe body; and a pressure ring disposable between the deformable ring and the collar of the end-fitting, wherein a ductility of the deformable ring is higher than a ductility of the pressure ring, and lower than a ductility of the polymer layer of the pipe body.

Description

[0001] FLEXIBLE PIPE SEALING

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

[0003] T rad itional ly 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 (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. 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.

[0009] 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.

[0010] 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, composite, or a combination of materials.

[0011] 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.

[0012] 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. 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 endfitting.

[0013] 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 riser, 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.

[0014] A cross-section of a known end-fitting assembly 300, such as that disclosed in W02007 / 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 end-fitting 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 301. The connector 304 can be connected directly to a matching connector of a further endfitting 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 end-fittings 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.

[0015] It is well-known that there are many varied problems associated with the provision of endfittings for ends of 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, flexible pipe body typically includes a fluid-retaining layer (known as a barrier layer or liner) 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.

[0016] It is an aim of the present invention to at least partly mitigate the above-mentioned problems.

[0017] According to a first aspect of the present invention there is provided a sealing assembly for an end-fitting of a flexible pipe, wherein the sealing assembly is disposable between a collar of the end-fitting and a polymer layer of a pipe body of the flexible pipe, the sealing assembly including: a deformable ring disposable radially outwardly of the polymer layer of the pipe body; and a pressure ring disposable between the deformable ring and the collar of the endfitting, wherein a ductility of the deformable ring is higher than a ductility of the pressure ring, and lower than a ductility of the polymer layer of the pipe body.

[0018] Suitably, the pressure ring is moveable between the deformable ring and the collar of the end-fitting such that the pressure ring engages and deforms the deformable ring.

[0019] Suitably, the pressure ring is energised, in use, such that the pressure ring is swaged against the deformable ring. Suitably, the deformable ring comprises a first surface and the pressure ring comprises a second surface, and suitably, the first surface of the deformable ring and the second surface of the pressure ring are inclined to one another.

[0020] Suitably, the second surface of the pressure ring is swaged against the first surface of the deformable ring.

[0021] Suitably, the first surface of the deformable ring is inclined at an angle of less than or equal to 45 degrees relative to a central, longitudinal axis of the sealing assembly.

[0022] Suitably, the deformable ring and / or the pressure ring comprise a trapezoidal shape.

[0023] Suitably, the deformable ring comprises brass.

[0024] Suitably, the pressure ring comprises a nickel alloy.

[0025] Suitably, the deformable ring is plastically deformable.

[0026] Suitably, the sealing assembly comprises a first seal disposed between the deformable ring and the pressure ring and / or a second seal disposed between the pressure ring and the collar of the end-fitting.

[0027] Suitably, the first seal and / or the second seal comprises an O-ring or an elastomeric ring.

[0028] Suitably, an inner surface of the deformable ring comprises serrations.

[0029] According to a second aspect of the present invention there is provided an end-fitting comprising: a sleeve insertable radially inwardly of a polymer layer of the pipe body; a collar disposed radially outwardly of the polymer layer of the pipe body, the collar comprising a recess adjacent to the polymer layer of the pipe body, in use; and a sealing assembly according to an aspect of the invention configured to be located in the recess of the collar.

[0030] Suitably, the pressure ring is moveable within the recess such that the pressure ring engages and deforms the deformable ring.

[0031] Suitably, the end-fitting comprises a jacket disposed adjacent to the collar.

[0032] Suitably, the recess comprises a void disposed between the pressure ring and the jacket, and suitably, the pressure ring is moveable within the recess towards the void.

[0033] Suitably, the pressure ring is energised, in use, such that the pressure ring is swaged towards the void and against the deformable ring.

[0034] Suitably, the collar comprises a pressure port configured to direct hydrostatic pressure onto the pressure ring.

[0035] According to a third aspect of the invention there is provided a flexible pipe comprising: a pipe body comprising a polymer layer; and an end-fitting comprising: a sleeve inserted radially inwardly of the polymer layer of the pipe body; a jacket comprising an external diameter greater than an external diameter of the sleeve; a collar disposed radially outwardly of the polymer layer of the pipe body, the collar comprising a recess adjacent to the polymer layer of the pipe body; and a sealing assembly according to an aspect of the invention configured to be located in the recess of the collar.

[0036] According to a fourth aspect of the invention there is provided a method comprising: providing a pipe body comprising a polymer layer; providing a sleeve of an end-fitting; inserting the sleeve radially inwardly of the polymer layer of the pipe body; providing a collar of the endfitting and disposing the collar radially outwardly of the polymer layer of the pipe body, the collar comprising a recess adjacent to the polymer layer of the pipe body; and providing a sealing assembly of the end-fitting according to an aspect of the invention and locating the sealing assembly in the recess of the collar. Suitably, the method comprises energising the pressure ring such that the pressure ring is swaged against the deformable ring, and the pressure ring engages and deforms the deformable ring.

[0037] 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 the pipe body is avoided. Certain embodiments provide the effect of a reduction in polymer creep, resulting in an improved seal between components of the end-fitting, particularly at deep water and ultra deep water pressures.

[0038] Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:

[0039] Fig. 1 illustrates an example pipe body;

[0040] Fig. 2 illustrates a riser assembly;

[0041] Fig. 3 illustrates an example end-fitting;

[0042] Fig. 4a illustrates an end-fitting of a flexible pipe according to an embodiment of the invention, during assembly;

[0043] Fig. 4b illustrates the end-fitting of Fig. 4a, partially assembled; Fig.

[0044] 5a illustrates the sealing assembly of the end-fitting of Fig. 4a; Fig.

[0045] 5b illustrates the sealing assembly of the end-fitting of Fig. 4b; Fig.

[0046] 6 illustrates the end-fitting of Fig. 4b, partially assembled; Fig. 7 illustrates the end-fitting of Fig. 6, fully assembled;

[0047] Fig. 8a illustrates the end-fitting of Fig. 7, in use;

[0048] Fig. 8b illustrates the sealing assembly of the end-fitting of Fig. 8a;

[0049] Fig. 9a illustrates a method of assembling a flexible pipe including an end-fitting and a pipe body according to an embodiment of the invention; and

[0050] Fig. 9b illustrates a further method of assembling a flexible pipe including an endfitting and a pipe body according to an embodiment of the invention. In the drawings like reference numerals refer to like parts.

[0051] Fig. 4a illustrates an end-fitting 400 of a flexible pipe 1000 according to an embodiment of the invention, during assembly, and Fig. 4b illustrates the end-fitting 400 of Fig. 4a, partially assembled (i.e. , a first collar 404a is connected to the end-fitting 400).

[0052] The end-fitting 400 includes a sleeve 402. The sleeve 402 is substantially tubular such that sleeve 402 includes a bore suitable to enable fluid flow therethrough, for example, oil or water. The sleeve 402 includes a first section 408a and a second section 408b. The first section 408a is disposed adjacent to the second section 408b. The first section 408a is disposed on a first side of transverse axis 452, and the second section 408a is disposed on a second side of 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. Optionally, the sleeve 402 may be coated with a low-friction coating system to improve the installation of the sleeve 402 under a polymer layer 504 of a pipe body 500. The polymer layer 504 may be an outer sheath of the pipe body 500.

[0053] The first section 408a is inserted radially inwardly of the polymer layer 504 of the pipe body 500. The first section 408a has a complimentary profile to an internal surface of the polymer layer 504. The external diameter of the first section 408a is substantially equal to the internal diameter of the polymer layer 504, such that the first section 408a and the polymer layer 504 are in contact with one another. The first section 408a supports an internal surface of the pipe body 500, such that the pipe body 500 is connected to the end-fitting 400. A first end of the first section 408a may include a tapered portion (not shown) configured to facilitate inserting the first section 408a radially inwardly of the polymer layer 504. Suitably, the tapered portion of the first section 408a of the sleeve 402 extends axially beyond a second end 442 of a first collar 404a of the end-fitting 400.

[0054] Suitably, the internal diameter of the sleeve 402 is substantially equal to the internal diameter of the polymer layer 504, such that the first section 408a of the sleeve 402 must be urged underneath the polymer layer 504, expanding an end portion of the internal and external diameters of the polymer layer 504 locally, where the first section 408a is inserted underneath. Suitably, in this configuration, the internal diameter of the sleeve 402 is substantially equal to an underlying layer of the pipe body 500, internal to the polymer layer 504. The second section 408b is not inserted radially inwardly of the polymer layer 504. The second section 408b has an external diameter greater than an external diameter of the first section 408a. The external diameter of the second section 408b is optionally equal to, or greater than, the external diameter of the polymer layer 504. The internal diameter of the second section 408b is equal to the internal diameter of the first section 408a, such that the bore of the sleeve 402 is continuous. An end face 505 of the end portion of the polymer layer 504 abuts the second section 408b, such that further insertion of the first section 408a, under the polymer layer 504, is prevented.

[0055] The end-fitting 400 includes a jacket 448 disposed radially outwardly of the second section 408b of the sleeve 402, and partially radially outwardly of the polymer layer 504 of the pipe body 500. Suitably, the internal diameter of jacket 448 is equal to, or greater than, the external diameter of the polymer layer 504. Suitably, the internal diameter of jacket 448 is equal to, or greater than, the external diameter of the end portion of the polymer layer 504, when the first section 408a of the sleeve 402 is inserted underneath the end portion of the polymer layer 504. Suitably, the internal diameter of jacket 448 is equal to, or greater than, the external diameter of the second section 408b of the sleeve 402. In some cases, the second section 408b of the sleeve 402 is connected (for example, welded) to the jacket 448.

[0056] Suitably, an external surface of the second section 408b is connected to an internal surface of the jacket 448.

[0057] As shown in Fig. 4a, the jacket 448 includes an array of first receiving portions 446a (only one of which is visible in Fig. 4a) for receiving an array of first fixings 456a (as shown in Fig.

[0058] 4b). The first fixings 456a are configured to join a first collar 404a of the end-fitting 400 to the jacket 448, and are aligned with respective receiving portions 444 in the first collar 404a. The receiving portions 446a of the jacket 448 and receiving portions 444 of the first collar 404a are disposed at a plurality of substantially evenly radially distributed points about a circumference of the jacket 448 and the first collar 404a. Suitably, each first fixing 456a is configured to extend from a second end 442 of the first collar 404a, through receiving portions 444 in the first collar 404a, and into each respective first receiving portion 446a in the jacket 448, each first receiving portion 446a being configured to receive the threaded shank end of each respective first fixing 456a. The jacket 448 further includes an array of second receiving portions 446b (only one of which is visible in Fig. 4a) for receiving an array of second fixings 456b (as shown in Fig. 6) configured to join a second collar 404b of the end-fitting 400 to the jacket 448, aligned with respective receiving portions in the second collar 404b. The second receiving portions 446b are disposed radially outwardly of the first receiving portions 446a. The second receiving portions 446b of the jacket 448 and receiving portions of the second collar 404b are disposed at a plurality of substantially evenly radially distributed points about a circumference of the jacket 448 and the second collar 404b. Suitably, each second fixing 456b is configured to extend from a second end of the second collar 404b, through receiving portions in the second collar 404b, and into each respective second receiving portion 446b in the jacket 448, each second receiving portion 446b being configured to receive the threaded shank end of a second fixing 456b.

[0059] The end-fitting 400 includes a first collar 404a. As shown in Fig. 4b, on partial assembly of the end-fitting 400 (i.e. , the first collar 404a is connected to the end-fitting 400), the first collar 404a is disposed adjacent to the jacket 448. The first collar 404a is disposed partially radially outwardly of the polymer layer 504 of the pipe body 500 and, in some cases, radially outwardly of a stepped section 449 of the jacket 448. The stepped section 449 may be disposed at end of the jacket 448, adjacent to the first collar 404a. The external diameter of the stepped section 449 may be less than the remaining portion of the jacket 448, such that the stepped section 449 is disposed within a recess 412 of the first collar 404a. The internal diameter of the first collar 404a is substantially equal to the external diameter of the end portion of the polymer layer 504, where it overlies the sleeve 402. The internal diameter of the first collar 404a is sized to be positioned over an external surface of the pipe body 500, when the pipe body 500 is connected to the end-fitting 400. The pipe body 500 is encapsulated by the first collar 404a on an external surface, and the first section 408a of the sleeve 402 on an internal surface. The first collar 404a is formed of a metal. In this case, the first collar 404a is formed of alloy steel. Optionally, a coating is applied to at least some surfaces of the first collar 404a to act as a barrier to corrosion.

[0060] The first collar 404a includes a recess 412 partially radially adjacent to the polymer layer 504 of the pipe body 500 and, in some cases, partially radially adjacent to the stepped section 449 of the sleeve 448. The recess 412 extends from a first end 440 of the first collar 404a to a position 425 part-way along the length of the first collar 404a. The recess 412 has a rectangular cross-section. The recess 412 is annular. The recess 412 is configured to receive a first sealing assembly 406a of the end-fitting 400 (as described later, in relation to Fig. 5a and 5b).

[0061] The first collar 404a optionally includes a first duct 438ai of a first pressure port 424a. As shown in relation to Fig. 4a, the first duct 438ai optionally extends from a second end 442 of the first collar 404a, through the first collar 404a, and to the interface between the first collar 404a and the polymer layer 504, such that the first duct 438ai is fluidly connected to the recess 412 via said interface. The first duct 438ai is configured to direct hydrostatic pressure onto a pressure ring 432 of the first sealing assembly 406a of the end-fitting 400 (as described later, in relation to Fig. 8b). In this case, the first duct 438ai terminates at a second position 427 part-way along the length of the first collar 404a. The second position 427 is spaced from the recess 412 along a length of the first collar 404a. That is to say, the extent position of the recess 412 from the first end 440 of the first collar 404a, and the second position 427 from the second end 442, are axially separated from each other by a portion of the length of the first collar 404a. The first duct 438ai is disposed at at least one point about a circumference of the first collar 404a.

[0062] As described above, the first collar 404a includes a receiving portion 444 for receiving a first fixing 456a configured to join the first collar 404a to the jacket 448. The first fixing 456a reduces an annular gap 471a between the jacket 448 and the first collar 404a, and secures the first collar 404a to the jacket 448, such that the end-fitting 400 is partially assembled. The first fixing 456a engages the first sealing assembly 406a (as described later, in relation to Fig. 5a and 5b).

[0063] The end-fitting 400 includes a first sealing assembly 406a. The first sealing assembly 406a is located in the recess 412 of the first collar 404a. The first sealing assembly 406a partially corresponds to the recess 412.

[0064] Fig. 5a illustrates the first sealing assembly 406a of the end-fitting 400 of Fig. 4a, during assembly of the end-fitting 400, and Fig. 5b illustrates the first sealing assembly 406a of end-fitting 400 of Fig. 4b, when the end-fitting 400 is partially assembled (i.e. , the first collar 404a is connected to the end-fitting 400).

[0065] The first sealing assembly 406a includes a deformable ring 426 and a pressure ring 432. The deformable ring 426 is disposed radially outwardly of the polymer layer 504 of the pipe body 500. The internal diameter of the deformable ring 426 is substantially equal to the external diameter of the polymer layer 504, such that the deformable ring 426 and the polymer layer 504 are in contact with one another. As shown in Fig. 5a, during assembly of the end-fitting 400, the deformable ring 426 has a first end disposed adjacent to the stepped section 449 of the jacket 448, and a second end disposed along the recess 412 such that there is an annular gap 471b between the deformable ring 426 and the first collar 404a. As shown in Fig. 5b, when the end-fitting 400 is partially assembled, the deformable ring 426 has a first end disposed adjacent to the stepped section 449 of the jacket 448, and a second end disposed adjacent to the first collar 404a (i.e. , the annular gap 471b is reduced).

[0066] The deformable ring 426 is formed of a metal. In this case, the deformable ring 426 is formed of brass. The ductility of the deformable ring 426 is lower than the ductility of the polymer layer 504.

[0067] The deformable ring 426 has a trapezoidal shape. The deformable ring 426 includes an outer surface 428. The outer surface 428 is inclined at angle of less than or equal to 45 degrees relative to a central, longitudinal axis of the first sealing assembly 406a. The outer surface 428 is inclined such that the external diameter of the deformable ring 426 is greater at the first end of the deformable ring 426 than the second end of the deformable ring 426.

[0068] The deformable ring 426 further includes an inner surface 430 disposed radially adjacent to the polymer layer 504. The inner surface 430 is oriented parallel to the central, longitudinal axis of the first sealing assembly 406a. The inner surface 430 is adjoined to the outer surface 428 of the deformable ring 426 by a first surface at the first end of the deformable ring 426 and a second surface at the second end of the deformable ring 426. The first surface and the second surface are oriented perpendicular to the central, longitudinal axis of the first sealing assembly 406a.

[0069] The first sealing assembly 406a includes a seal 418 disposed between the deformable ring 426 and the pressure ring 432 of the first sealing assembly 406a. More specifically, the seal 418 is disposed between the outer surface 428 of the deformable ring 426 and an inner surface 434 of the pressure ring 432. The seal 418 is disposed substantially mid-way along a length of the outer surface 428 of the deformable ring 426. The seal 418 includes an O- ring or an elastomeric ring.

[0070] The pressure ring 432 is disposed radially outwardly of the deformable ring 426. More specifically, the pressure ring 432 is disposed between the deformable ring 426 and the first collar 404a. The internal diameter of the pressure ring 432 is substantially equal to the external diameter of the deformable ring 426, such that the pressure ring 432 and the deformable ring 426 are in contact with one another. The external diameter of the pressure ring 432 is substantially equal to an internal diameter of the first collar 404a, such that the pressure ring 432 and the first collar 404a are in contact with one another. As shown in Fig. 5a and 5b, during assembly of the end-fitting 400 and when the end-fitting 400 is partially assembled, the pressure ring 432 has a first end at a position along the recess 412, and a second end adjacent to the first collar 404a. The part of the recess 412 between the first end of the pressure 432 and the jacket 448 is defined as a void 416 (as described later, in relation to Fig. 8b).

[0071] The pressure ring 432 is formed of a metal. In this case, the pressure ring 432 is formed of a nickel alloy. The ductility of the deformable ring 426 is higher than a ductility of the pressure ring 432.

[0072] The pressure ring 432 has a trapezoidal shape. The pressure ring 432 includes an inner surface 434. The inner surface 434 is inclined at an angle of less than or equal to 45 degrees relative to a central, longitudinal axis of the first sealing assembly 406a. The inner surface 434 is inclined such that the internal diameter of the pressure ring 432 is greater at a second end of the pressure ring 432 than the first end of the pressure ring 432. The inner surface 434 of the pressure ring 432 corresponds to the outer surface 428 of the deformable ring 426.

[0073] The pressure ring 432 further includes an outer surface 454 disposed radially adjacent to the first collar 404a. The outer surface 454 is oriented parallel to the central, longitudinal axis of the first sealing assembly 406a. The outer surface 454 is adjoined to the inner surface 434 of the pressure ring 432 by a first surface at the first end of the pressure ring 432 and a second surface at the second end of the pressure ring 432. The first surface and the second surface of the pressure ring 432 are oriented perpendicular to a longitudinal axis of the first sealing assembly 406a. The first sealing assembly 406a includes a further seal 422 disposed between the pressure ring 432 and the first collar 404a. More specifically, the further seal 422 is disposed between the outer surface 454 of the pressure ring 432 and the first collar 404a. The further seal 422 is disposed substantially mid-way along a length of the outer surface 454 of the pressure ring 432. The further seal 422 includes an O-ring or an elastomeric ring.

[0074] As shown in Fig. 5a, during assembly of the end-fitting 400, the first collar 404a and the jacket 448 are not joined to one another, such that an annular gap 471a is provided between the first collar 404a and the jacket 448. As described above, during assembly of the endfitting 400, a second end of the deformable ring 426 is disposed along the recess 412, such that there is a further annular gap 471b between the deformable ring 426 and the first collar 404a. The annular gap 471a between the first collar 404a and the jacket 448 corresponds in width to the further annular gap 471b between the deformable ring 426 and the first collar 404a.

[0075] As further shown in Fig. 5a, the inner surface 434 of the pressure ring 432 and the outer surface 428 of the deformable ring 426 are inclined to one another, such that the deformable ring 426 temporarily restricts movement of the pressure ring 432 along a central, longitudinal axis of the first sealing assembly 406a, towards the jacket 448.

[0076] To join the first collar 404a to the jacket 448, and partially assemble the end-fitting 400, the first collar 404a is moved towards the jacket 448, such that the annular gap 471a between the first collar 404a and the jacket 448 (and the further annular gap 471b between the deformable ring 426 and the first collar 404a) is reduced. As stated above, a second end of the pressure ring 432 is disposed adjacent to the first collar 404a. As such, moving the first collar 404a towards the jacket 448, in turn, energises the pressure ring 432 to move along the central, longitudinal axis of the first sealing assembly 406a and towards the jacket 448, and swage against the deformable ring 426. More specifically, the inner surface 434 of the pressure ring 432 swages against the outer surface 428 of the deformable ring 426.

[0077] Due to the ductility of the deformable ring 426 being higher than that of the pressuring ring 432, when the pressure ring 432 is swaged against the deformable ring 426, the pressure ring 432 deforms the deformable ring 426. More specifically, the inner surface 434 of the pressure ring 432 deforms the outer surface 428 of the deformable ring 426. The deformable ring 426 is deformed such that the pressure ring 432 is no longer restricted and movement along a central, longitudinal axis of the first sealing assembly 406a, towards the jacket 448 is permitted. The deformable ring 426 is deformed such that the external diameter of the deformable ring 426 is altered. For example, the external diameter of the first end of the deformable ring 426 is reduced, enabling movement of the pressure ring 432, towards the jacket 448. The first sealing assembly 406a is configured such that movement of the pressure ring 432 is resisted and / or the pressure required to energise the pressure ring 432 is appropriately controlled. For example, decreasing the ratio of ductility between the deformable ring 426 and the pressure ring 432 increases the pressure required to energise the pressure ring 436, and move the pressure ring 436 along the central, longitudinal axis of the first sealing assembly 406a and towards the jacket 448.

[0078] The pressure ring 432 is swaged against the deformable ring 426 such that, in addition to deforming the deformable ring 426, the deformable ring 426 is also compressed against the polymer layer 504 of the pipe body 500 and / or the stepped section 449 of the jacket 448. As the pressure ring 432 moves towards the jacket 448, the amount of compression the deformable ring 426 exerts on the polymer layer 504 and / or stepped section 449 increases. Compressing the deformable ring 426 against the polymer layer 504 and / or stepped section 449, in this manner, prevents fluid ingress between the deformable ring 426 and the polymer layer 504 and / or the stepped section 449. Fluid ingress is prevented, in this manner, by reducing the width of the interface between the deformable ring 426 and the polymer layer 504 and / or the stepped section 449.

[0079] The pressure ring 432 is swaged against the deformable ring 426 until the first collar 404a and the jacket 448 and, in turn, the deformable ring 426 and the first collar 404a, are in contact with one another. When the first collar 404a and the jacket 448, and, in turn, the deformable ring 426 and the first collar 404a, are in contact with one another, the end-fitting 400 is in a partially assembled configuration, as shown in Fig. 4b and 5b.

[0080] As further shown in Fig. 5b, following partial assembly, the deformable ring 426 is restricted from movement parallel to the central, longitudinal axis of the first sealing assembly 406a. At the first end of the deformable ring 426, movement is restricted by the stepped section 449 of the jacket 448, and at the second end of the deformable ring 426, movement is restricted by the first collar 404a. As described above, in relation to Fig. 5a, the inner surface 434 of the pressure ring 432 and the outer surface 428 of the deformable ring 426 are inclined to one another such that the deformable ring 426 temporarily restricts movement of the pressure ring 432 along a central, longitudinal axis of the first sealing assembly 406a.

[0081] Fig. 6 further illustrates the end-fitting of Fig. 4b, partially assembled (i.e. , a first collar 404a and a second collar 404b connected to the end-fitting 400).

[0082] As shown in Fig. 6, the end-fitting 400 includes a second collar 404b. A first portion of the second collar 404b is partially disposed radially outwardly of the polymer layer 504 of the pipe body 500, in a similar manner as the first collar 404a of the end-fitting 400 (as described above, in relation to Fig. 4a and 4b). A second portion of the second collar 404b is disposed radially outwardly of the first collar 404a, such that the first collar 404a is encapsulated by the second collar 404b. The second collar 404b is integral in construction. The second collar 404b is formed of a metal. In this case, the second collar 404b is formed of alloy steel.

[0083] Optionally, a coating is applied to at least some surfaces of the second collar 404b to act as a barrier to corrosion.

[0084] The second collar 404b includes a recess partially radially adjacent to the polymer layer 504 of the pipe body 500 and, in some cases, also radially adjacent to the stepped section of the first collar 404a. The recess extends from a first end of the second collar 404b, adjacent to the first collar 404a, to a position part-way along the length of the second collar 404b. The recess has a rectangular cross-section. The recess is annular. The recess is configured to receive a second sealing assembly 406b of the end-fitting 400 (as shown in Fig. 6). In a similar manner to that described in relation to Fig. 5a and 5b, the pressure ring of the second sealing assembly 406b is configured to swage against the respective deformable ring of the second sealing assembly 406b, such that fluid ingress between the polymer layer 504 and the second sealing assembly 406b is prevented.

[0085] The second collar 404b includes a further recess partially radially adjacent to the polymer layer 504 of the pipe body 500 and, in some cases, also radially adjacent to a stepped section of a third collar 404c of the end-fitting 400. The further recess extends from a second end of the second collar 404b, adjacent to the third collar 404c, to a position part-way along the length of the second collar 404a (spaced from the position in which the recess, as described above, terminates). The further recess has a rectangular cross-section. The further recess is annular. The further recess is configured to receive a third sealing assembly 406c of the end-fitting 400 (as described in relation to Fig. 7).

[0086] The second collar 404b optionally includes a second duct 438a2 and an opening 436a of the first pressure port 424a. The second duct 438a2 optionally extends from the opening 436a, disposed on an external surface of the second collar 404b, through the second collar 404b, and to the first duct 438ai of the first collar 404a, such that the second duct 438a2 is fluidly connected to the first duct 438ai, and in turn, the recess 412 of the first collar 404a. The second duct 438a2 is disposed at at least one point about a circumference of the second collar 404b. The second duct 438a2 is aligned with the first duct 438ai of the first collar 404a at the interface between the first duct 438ai and second duct 438a2. The opening 436a of the first pressure port 424a has a generally rectangular cross-section. Optionally, the opening 436a is annular. Optionally, the opening 436a is not annular and is one of a plurality of drilled holes of circular cross-section. Optionally, the opening 436a is not annular and is one of a plurality of openings 436a milled into the second collar 404b and evenly radially distributed, each of which has an oval or polygonal cross-section.

[0087] The second collar 404b optionally includes a second pressure port 424b, spaced from the first pressure port 424a along the length of the second collar 404b. The second pressure port 424b includes a duct 438b and an opening 436b. The duct 438b optionally extends from the opening 436b, disposed on an external surface of the second collar 404b, through the second collar 404b, and to an interface between the second collar 404b and the polymer layer 504, such that the duct 438b is fluidly connected to the recess and further recess of the second collar 404b via the interface. The duct 438b of the second pressure port 424b is configured to direct hydrostatic pressure onto pressure rings of the second sealing assembly 406b and the third sealing assembly 406c, as described later, in relation to Fig. 8b. The duct 438b is disposed at at least one point about a circumference of the second collar 404b. The opening 436b of the second pressure port 424b is configured in a similar manner to the opening 436a of the first pressure port 424a.

[0088] As described above, in relation to Fig. 4a and 4b, the second collar 404b includes a receiving portion for receiving a second fixing 456b configured to join the second collar 404b to the jacket 448. The second fixing 456b reduces an annular gap between the jacket 448 and the second collar 404b (and the second collar 404b and the first collar 404a), and secures the second collar 404b to the jacket 448, such that the end-fitting 400 is partially assembled (i.e. , the second collar 404b is connected to the end-fitting 400). The second fixing 456b further engages the second sealing assembly 406b (in a similar manner as described above, in relation to Fig. 5a and 5b).

[0089] The second collar 404b further includes further receiving portions (only one of which is visible in Fig. 6) for receiving an array of third fixings 456m (as shown in Fig. 7). The third fixings 456m are configured to join the third collar 404c to the second collar 404b, and are aligned with respective receiving portions in the third collar 404c. The further receiving portions of the second collar 404b and receiving portions of the third collar 404c are disposed at a plurality of substantially evenly radially distributed points about a circumference of the second collar 404b and the third collar 404c. Suitably, each third fixing 456m is configured to extend from a second end of the third collar 404c, through receiving portions in the third collar 404, and into each respective further receiving portion in the second collar 404b.

[0090] Fig. 7 further illustrates the end-fitting 400 of Fig. 6, fully assembled (i.e. , a first collar 404a, a second collar 404b, and a third collar 404c connected to the end-fitting 400).

[0091] As shown in Fig. 7, the end-fitting 400 includes a third collar 404c. The third collar 404c is disposed radially outwardly of the polymer layer 504 of the pipe body 500, in a similar manner as the first collar 404a of the end-fitting 400 (as described above, in relation to Fig. 4a and 4b). The third collar 404c is formed of a metal. In this case, the third collar 404c is formed of alloy steel. Optionally, a coating is applied to at least some surfaces of the third collar 404c to act as a barrier to corrosion.

[0092] As described above, in relation to Fig. 6, the third collar 404c includes a receiving portion for receiving a third fixing 456m configured to join the third collar 404c to the second collar 404c. The first fixing 456m secures the third collar 404c to the second collar 404b, such that the end-fitting 400 is fully assembled.

[0093] In some cases, the third collar 404c includes a further receiving portion for receiving a fourth fixing 456C2 configured to energise a pressure ring of the third sealing assembly 406c, disposed in the further recess of the second collar 404b, aligned with receiving portions of said pressure ring. The further receiving portions of the third collar 404c and receiving portions of the pressure ring of the third sealing assembly 404c are disposed at a plurality of substantially evenly radially distributed points about a circumference of the third collar 404c and the pressure ring. Suitably, each fourth fixing 456C2 is configured to extend from a second end of the third collar 404c, through further receiving portions in the third collar 404c, and into each respective receiving portions of the pressure ring of the third sealing assembly 406c.

[0094] In a similar manner to that described in relation to Fig. 5a and 5b, the pressure ring of the third sealing assembly 406c is configured to swage against the respective deformable ring of the third sealing assembly 406c, such that fluid ingress between the polymer layer 504 and the third sealing assembly 406c is prevented.

[0095] Fig. 8a further illustrates the end-fitting 400 of Fig. 7, in use, and, by way of example, Fig. 8b illustrates the first sealing assembly 406a of the end-fitting of Fig. 8a (i.e., when the endfitting 400 is in use).

[0096] In use, when the flexible pipe 1000 comprising the end-fitting 400 is deployed, the energisation of each of the pressure rings 432 of the respective sealing assemblies 406a, 406b, 406c is maintained, or increased, by hydrostatic pressure acting on said pressure rings 432. The hydrostatic pressure is directed towards the pressure rings 432 via the ducts 438ai, 438a2, 438b of the pressure ports 424a, 424b. The amount of pressure acting on the pressure rings 432 increases with the depth the flexible pipe 1000 including the end-fitting 400 is submerged.

[0097] As shown in Fig. 8a and 8b, the hydrostatic pressure acting on the pressure rings 432 moves the pressure rings 432 towards the respective voids 416, such that the pressure rings 432 swage against the respective deformable rings 426, and the seal between the deformable ring 426 and the polymer layer 504 is maintained, preventing fluid ingress. More specifically, the inner surface 434 of the pressure rings 432 are swaged against the outer surface 428 of the respective deformable rings 426. As the hydrostatic pressure acting on the pressure rings 432 increase, the pressure rings 432 continue to swage against the respective deformable rings 426 and the pressure ring 432 move towards and, optionally into, the void 416. As shown in Fig. 8b, the pressure ring 432 is partially disposed in the void 416. The first seals 418, disposed between the pressure rings 432 and the deformable ring 426s, and the second seals 422, disposed between the pressure rings 432 and the collars 404a, 404b, 404c, further contribute to preventing fluid ingress. Fig. 9a illustrates a method 600 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 600 includes the step 602 of providing a pipe body 500 of a flexible pipe 1000 comprising a polymer layer 504.

[0099] The method 600 further includes the step 604 of providing a sleeve 402 of an end-fitting 400 of the flexible pipe 1000. The sleeve 402 includes a first section 408a and a second section 408b. The second section 408b has an external diameter greater than an external diameter of the first section 408a.

[0100] The method 600 further includes the step 606 of inserting the first section 408a of sleeve 402 radially inwardly of the polymer layer 504 of the pipe body 500.

[0101] The method 600 further includes the step 608 providing a collar 404 of the end-fitting 400 and disposing the collar 404 radially outwardly of the polymer layer 504 of the pipe body 500. The collar 404 includes a recess 412 adjacent to the polymer layer 504 of the pipe body 500.

[0102] The method 600 further includes the step 610 providing a sealing assembly and disposing the sealing assembly 406 between the collar 404 and the polymer layer 504. The sealing assembly 406 includes a deformable ring 426 disposable radially outwardly of the polymer layer 504, and a pressure ring 432 disposable between the deformable ring 426 and the collar 404. The ductility of the deformable ring 426 is higher than a ductility of the pressure ring 432, and lower than a ductility of the polymer layer 504.

[0103] Fig. 9b illustrates a method 650 of assembling a flexible pipe 1000 including an end-fitting 400 and a pipe body 500 according to an embodiment of the invention.

[0104] The method 650 includes the steps 602, 604, 606, 608, 610 of method 600. The method 650 further includes the step 612 of energising the pressure ring 432 such that the pressure ring 432 is swaged against the deformable ring 426, and the pressure ring 432 engages and deforms the deformable ring 426.

[0105] Various modifications to the detailed arrangements as described above are possible.

[0106] The outer surface of the first section 408a of the sleeve 402 and / or the inner surface of the polymer layer 504 of the pipe body 500 may include serrations, such that the first section 408a and the polymer layer 504 form an interference fit. The serrations may form a labyrinth profile.

[0107] The polymer layer 504 of the pipe body 500 may be formed from polyethylene, a polyamide, or any other suitable material.

[0108] Instead of the polymer layer 504 being an outer sheath of the pipe body 500, the polymer layer 504 may be any layer of the pipe body 500. The polymer layer 504 may include multiple layers of the pipe body 500.

[0109] The tapered portion of the sleeve 402 may be configured to prevent gap formation between the first section 408a of the sleeve 402 and the polymer layer 504 of the pipe body 500.

[0110] The pressure ring 432 may be corrosion resistant.

[0111] Instead of the jacket 448 and first collar 404a and / or second collar 404b being joined by fixings 456a, 456b, the jacket 448 may be joined to the first collar 404a and / or second collar 404b by any means known in the art, for example, welding, use of adhesives, or mechanical joints.

[0112] Instead of the recess 412 including a rectangular cross-section, the recess 412 may include any shape suitable to receive the respective sealing assembly 406a, 406b, 406c. Instead of the recess 412 being annular, the recess 412 may not be annular (i.e., may be disposed at discontinuous point(s) around a circumference of the first collar 404a and / or second collar 404b and / or third collar 404c.

[0113] Instead of the deformable ring 426 and the pressure 432 being trapezoidal in shape, the deformable ring 426 and the pressure ring 432 may include any shape such that the pressure ring 432 may be swaged against the deformable ring 426.

[0114] The deformable ring 426 may be plastically deformable or elastically deformable.

[0115] The sealing assembly 406 may not include any of the first seal 418 and / or the second seal 422.

[0116] Instead of the first seal 418 and / or second seal 422 including an O-ring or an elastomeric ring, the first seal 418 and / or the second seal 422 may include spiral gasket-type seal.

[0117] Instead of a triple seal and triple collar arrangement, as shown in Fig. 7 and 8a, a double seal, double collar arrangement, similar to that shown in Fig. 6 may be configured without the need for a third collar 404c or a third sealing assembly 406c, without detriment to performance.

[0118] The orientation of the components of the sealing assemblies 406a, 406b, 406c may be reversed, and likewise ducts 438a, 438b may be re-routed to account for such a change in seal orientation.

[0119] The precise dimensions of the parts of the end-fitting have been described for example only.

[0120] With the above-described arrangement, the deformable ring has a ductility value between that of the pressure ring and the polymer layer of the pipe body. This enables a good seal between the radially outer part of the end-fitting and the layer of pipe, and a good connection when joining the pressure ring and the polymer layer. With the above-described arrangement, a first collar and / or second collar and / or third collar of the end-fitting is disposed radially outwardly of the connection between the polymer layer of the pipe body and the deformable ring. The connection between the polymer layer and the deformable ring is thereby protected from failure, providing an improved connection between the end-fitting and the pipe body.

[0121] With the above-described arrangement, disposing the sealing assembly in a recess adjacent to the polymer layer of the pipe body enables the end-fitting to utilise hydrostatic pressures to increase the compressive force acting on the pressure ring and, in turn, the deformable ring, thereby further improving the seal and preventing fluid ingress between the first collar and / or second collar and / or third collar and the polymer layer.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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. A sealing assembly for an end-fitting of a flexible pipe, wherein the sealing assembly is disposable between a collar of the end-fitting and a polymer layer of a pipe body of the flexible pipe, the sealing assembly comprising: a deformable ring disposable radially outwardly of the polymer layer of the pipe body; and a pressure ring disposable between the deformable ring and the collar of the endfitting, wherein a ductility of the deformable ring is higher than a ductility of the pressure ring, and lower than a ductility of the polymer layer of the pipe body.

2. A sealing assembly according to claim 1 , wherein the pressure ring is moveable between the deformable ring and the collar of the end-fitting such that the pressure ring engages and deforms the deformable ring.

3. A sealing assembly according to claim 2, wherein the pressure ring is energised, in use, such that the pressure ring is swaged against the deformable ring.

4. A sealing assembly according to any of the preceding claims, wherein the deformable ring comprises a first surface and the pressure ring comprises a second surface, and wherein the first surface of the deformable ring and the second surface of the pressure ring are inclined to one another.

5. A sealing assembly according to claim 4, wherein the second surface of the pressure ring is swaged against the first surface of the deformable ring.

6. A sealing assembly according to claim 4 or 5, wherein the first surface of the deformable ring is inclined at an angle of less than or equal to 45 degrees relative to a central, longitudinal axis of the sealing assembly.

7. A sealing assembly according to any of claims 4 to 6, wherein the deformable ring and / or the pressure ring comprise a trapezoidal shape.

8. A sealing assembly according to any of the preceding claims, wherein the deformable ring comprises brass.

9. A sealing assembly according to any of the preceding claims, wherein the pressure ring comprises a nickel alloy.

10. A sealing assembly according to any of the preceding claims, wherein the deformable ring is plastically deformable.

11. A sealing assembly according to any of the preceding claims, wherein the sealing assembly comprises: a first seal disposed between the deformable ring and the pressure ring; and / or a second seal disposed between the pressure ring and the collar of the end-fitting.

12. A sealing assembly according to claim 11, wherein the first seal and / or the second seal comprises an O-ring or an elastomeric ring.

13. A sealing assembly according to any of the preceding claims, wherein an inner surface of the deformable ring comprises serrations.

14. An end-fitting for joining to a pipe body, wherein the end-fitting comprises:a sleeve insertable radially inwardly of a polymer layer of the pipe body; a collar disposed radially outwardly of the polymer layer of the pipe body, the collar comprising a recess adjacent to the polymer layer of the pipe body, in use; and a sealing assembly according to any of the preceding claims configured to be located in the recess of the collar.

15. An end-fitting according to claim 14, wherein the pressure ring is moveable within the recess such that the pressure ring engages and deforms the deformable ring.

16. An end-fitting according to claim 15, wherein the end-fitting comprises a jacket disposed adjacent to the collar.

17. An end-fitting according to claim 16, wherein the recess comprises a void disposed between the pressure ring and the jacket, and wherein the pressure ring is moveable within the recess towards the void.

18. An end-fitting according to claim 17, wherein the pressure ring is energised, in use, such that the pressure ring is swaged towards the void and against the deformable ring.

19. An end-fitting according to claim 18, wherein the collar comprises a pressure port configured to direct hydrostatic pressure onto the pressure ring.

20. A flexible pipe, wherein the flexible pipe comprises: a pipe body comprising a polymer layer; and an end-fitting comprising: a sleeve inserted radially inwardly of the polymer layer of the pipe body;a jacket comprising an external diameter greater than an external diameter of the sleeve; a collar disposed radially outwardly of the polymer layer of the pipe body, the collar comprising a recess adjacent to the polymer layer of the pipe body; and a sealing assembly according to any of claims 1 to 13 configured to be located in the recess of the collar.

21. 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; inserting the sleeve radially inwardly of the polymer layer of the pipe body; providing a collar of the end-fitting and disposing the collar radially outwardly of the polymer layer of the pipe body, the collar comprising a recess adjacent to the polymer layer of the pipe body; and providing a sealing assembly of the end-fitting according to any of claims 1 to 13 and locating the sealing assembly in the recess of the collar.

22. A method according to claim 21, wherein the method comprises energising the pressure ring such that the pressure ring is swaged against the deformable ring, and the pressure ring engages and deforms the deformable ring.

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