Endpiece of a flexible pipe for transporting fluid, flexible pipe and associated method

Abstract

The endpiece (14) comprises a rear sealing assembly (56) between the cover (51) and the outer sheath (30), comprising: - an outer ring (110) arranged between the outer sheath (30) and the cover (51); - at least one outer seal (112A, 112B), borne by the outer ring (110) and interposed between the outer ring (110) and the cover (51); - at least one inner seal (114A, 114B), borne by the outer ring (110) and interposed between the outer ring (110) and the outer sheath (30).

Description

[0001] DESCRIPTION

[0002] TITLE: Flexible fluid transport pipe end fitting, flexible pipe and associated process

[0003] The present invention relates to a flexible fluid transport pipe end fitting, comprising: at least one end region of an outer polymer sheath; end sections of armor elements of the flexible pipe, arranged inside the outer polymer sheath; an end arch, defining a central fluid circulation bore extending along a central axis; a hood defining with the end arch a receiving chamber for the end sections of armor elements and the end region of the outer sheath; a rear anchoring assembly for the outer sheath relative to the hood.

[0004] The flexible pipeline is in particular a flexible pipeline of the unbonded type intended for the transport of hydrocarbons across a body of water, such as an ocean, a sea, a lake or a river.

[0005] Such flexible management is for example carried out in accordance with the normative documents API 17J, 5th edition May 2024 and API RP 17B, 6th edition - May 2024, established by the American Petroleum Institute.

[0006] The pipe is generally formed from a series of concentric and superimposed layers. It is considered "unbonded" within the meaning of the present invention when at least one of the pipe layers is capable of moving longitudinally relative to the adjacent layers during pipe bending. In particular, an unbonded pipe is a pipe lacking bonding materials connecting the layers forming the pipe.

[0007] The pipeline is typically laid across a body of water, between a bottom assembly, designed to collect the extracted fluid from the bottom of the body of water, and a floating surface assembly designed to collect and distribute the fluid. The surface assembly can be a semi-submersible platform, an FPSO (Floating Production Storage and Offloading) system, or another floating assembly.

[0008] In a known manner, the flexible hose comprises a polymer pressure sheath, designed to contain the fluid carried by the hose, and an outer sheath (hereafter referred to as the "outer sheath") designed to protect the flexible hose externally, particularly from water ingress into the annular space between the pressure sheath and the outer sheath. The outer sheath is generally the outermost sheath of the flexible hose, or alternatively, an intermediate sheath between the pressure sheath and the outermost sheath of the hose.

[0009] The ends of the flexible hose have fittings for connection to the base and surface assemblies. The end section of each hose is received into a fitting on the hose and is sealed into the fitting.

[0010] To this end, a known solution for making a watertight connection is to crimp a metal ring around the outer face of the sheath so that the ring partially penetrates the thickness of the sheath wall.

[0011] The crimped ring is generally shaped like a hollow cone surrounding the sleeve, with this cone positioned coaxially with the sleeve. During crimping, a conical bearing surface machined into the body of the ferrule or present in a flange assembled onto the ferrule is pushed axially around this cone, this conical bearing surface also being coaxial with the sleeve to be crimped and with the cone.

[0012] During this crimping process, the cone is compressed radially relative to the sheath axis, its diameter decreases, and it undergoes plastic deformation as it partially penetrates the sheath. This crimping operation simultaneously ensures a metal-to-polymer seal between the cone and the sheath, and a metal-to-metal seal between the cone and the nozzle body. In addition to the seal, the crimped ring provides axial anchoring of the sheath relative to the nozzle.

[0013] This solution withstands very high internal pressures (over 1000 bar) across a wide temperature range (up to 130°C and above), particularly when the pressure inside the sheath is greater than the pressure outside. This pressure difference tends to increase the sheath's diameter. This, in turn, increases the contact pressure between the sheath and the crimping ring, as well as between the crimping ring and the fitting body, thus strengthening the seal of the assembly.

[0014] However, the external hydrostatic pressure acting on the outer face of the outer sheath is often greater than the internal pressure acting on the inner face of the outer sheath from inside the pipe. This is detrimental to the crimping between the outer sheath and the fitting cap, especially when the fitting is submerged at great depths.

[0015] Furthermore, other phenomena, such as local creep of the outer sheath under the effect of hydrostatic pressure and temperature, can occur, further weakening the quality of the crimping, and can cause, in some cases, the outer sheath to detach from the crimped ring.

[0016] This can lead to a leak around the outer sheath at the nozzle, and cause flooding of the annular space between the outer sheath and the pressure sheath.

[0017] This flooding is often critical, especially when the pressure vault and tensile armor present in the annular space are susceptible to corrosion.

[0018] This is the case, for example, when acidic gases from the fluid circulating inside the pressure sheath diffuse through the pressure sheath and strong mechanical stresses are applied to these armors, creating conditions favorable to the formation of stress corrosion cracking (SCC).

[0019] One object of the invention is to provide a flexible fluid transport conduit end fitting that significantly improves the seal between the outer sheath and the end cap, in particular to prevent flooding of the annular space and the formation of stress corrosion of the metallic reinforcement elements.

[0020] To this end, the invention relates to a flexible fluid transport pipe fitting of the aforementioned type, characterized in that the fitting comprises a rear sealing assembly between the cover and the outer sheath, the rear sealing assembly comprising: an outer ring disposed between the outer sheath and the cover; at least one external sealing gasket carried by the outer ring and interposed between the outer ring and the cover; at least one internal sealing gasket, carried by the outer ring, and interposed between the outer ring and the outer sheath.

[0021] The nozzle according to the invention may comprise one or more of the following features, taken individually or in any technically possible combinations: the external sealing ring or rings extend over an external peripheral surface of the outer ring, the internal sealing ring or rings extend over an internal peripheral surface of the outer ring; the rear sealing assembly comprises at least two adjacent external sealing rings carried by the outer ring, and / or at least two adjacent internal sealing rings carried by the outer ring;the outer ring defines, for the external seal or each external seal, an external housing, the external seal or each external seal comprising a base received in the external housing, and a point projecting out of the external housing to apply to the cover and / or for the external seal or each external seal, an internal housing, the internal seal or each internal seal comprising a base received in the internal housing, and a point projecting out of the internal housing to apply to the external sheath; the outer ring comprises a base ring and a fixing collar, projecting radially outwards from the base ring, the fixing collar being fixed to a rear edge of the cover, the base ring comprising an internal peripheral surface carrying the internal seal or each internal seal and an external peripheral surface carrying the external seal or each external seal;the base ring defines a through passage connecting the inner peripheral surface to the outer peripheral surface by passing through the base ring, the hood advantageously comprising at least one test port extending radially through the base ring, the test port opening opposite the through passage; the outer peripheral surface of the base ring defines a front chamfer disposed opposite the fixing collar; the rear sealing assembly comprises a support cannula inserted between the end sections of the armor elements and the end region of the outer sheath, the end region of the outer sheath being wedged between the outer ring and the support cannula;the support cannula comprises a tubular support section, inserted under the outer sheath, and a front heel, projecting radially from the tubular support section, at the front of the support cannula, opposite a slice of the end region of the outer sheath, the slice of the end region of the outer sheath being wedged against the front heel; it comprises a radial retaining ring for the end sections of the armor elements, applied to the end sections of the armor elements and / or a gas drain collar, fixed axially around the end sections of the armor elements, the support cannula being disposed as an axial abutment against the radial retaining ring and / or against the gas drain collar;The rear anchoring assembly includes a rear crimping ring having a bulge that fits into the end region of the outer sheath; the rear anchoring assembly includes a rear clamping flange having an inclined surface for radial movement of the rear crimping ring; it includes at least one fixing member for the outer ring on the hood having a rearward projecting head outside the outer ring; the rear clamping flange defining a receiving recess for the projecting head when the rear clamping flange is fixed to the rear edge of the hood by being applied against the outer ring.

[0022] The invention also relates to a flexible fluid transport conduit, comprising a central section including: at least one outer polymer sheath; reinforcement elements of at least one layer of tensile reinforcement arranged in the outer sheath; the flexible conduit including at least one end fitting as defined above, mounted at one end of the central section

[0023] The invention also relates to a method for assembling a flexible fluid transport pipe fitting comprising the following steps:

[0024] - arrangement of at least one end region of an outer polymer sheath, and end sections of flexible pipe armor elements, arranged inside the outer polymer sheath, between an end arch, defining a central fluid circulation bore extending along a central axis and a hood defining with the end arch a receiving chamber for the end sections of armor elements and the end region of the outer sheath;

[0025] - Installation of a rear anchoring assembly for the outer sheath relative to the cover, characterized by the mounting of a rear sealing assembly between the cover and the outer sheath, the rear sealing assembly comprising:

[0026] - an external ring positioned between the outer sheath and the cover;

[0027] - at least one external sealing gasket carried by the outer ring and interposed between the outer ring and the cover;

[0028] - at least one internal sealing gasket, carried by the outer ring, and interposed between the outer ring and the outer sheath.

[0029] The method according to the invention may include one or more of the following features, taken individually or in any technically possible combination: the rear sealing assembly is mounted before the rear anchoring assembly is installed; the rear sealing assembly includes at least one front internal sealing gasket and at least one rear internal sealing gasket carried by the outer ring, the outer ring including a base ring comprising an inner peripheral surface carrying each internal sealing gasket and an outer peripheral surface carrying the or each external sealing gasket, the base ring defining a through passage connecting the inner peripheral surface to the outer peripheral surface by passing through the base ring and opening between the front internal sealing gasket and the rear internal sealing gasket;the assembly of the rear sealing assembly including the lubrication of the end region of the outer sheath in front of the front inner sealing ring, the forward movement of the outer ring on the end region of the outer sheath and the simultaneous addition of lubricant to the end region of the outer sheath between the front inner sealing ring and the rear inner sealing ring via the through passage.;

[0030] The invention will be better understood upon reading the following description, given solely by way of example, and made with reference to the attached drawings, in which:

[0031] - [Fig. 1] Figure 1 is a partially cutaway perspective view of a first flexible conduit according to the invention;

[0032] - [Fig. 2] Figure 2 is a cross-sectional view, taken along a median axial plane, of the relevant parts of the flexible pipe end of Figure 1, illustrating a rear sealing assembly between the outer sheath and the hood, and an anchoring assembly of the outer sheath relative to the hood;

[0033] - [Fig. 3] Figure 3 is an elevation view of the outer ring of the rear sealing assembly;

[0034] - [Fig. 4] Figure 4 is a view of a detail of the outer ring of the rear sealing assembly, during insertion of the outer ring into the end cap;

[0035] - [Fig. 5] Figure 5 is a view analogous to Figure 4, after the insertion of the outer ring into the cap of the tip and when a crimping ring is placed on the outer sheath;

[0036] - [Fig. 6] Figure 6 is a view analogous to figure 2 of a variant of flexible driving according to the invention;

[0037] - [Fig. 7] Figure 7 is a view analogous to figure 2 of another variant of flexible driving according to the invention.

[0038] Throughout this text, the terms "outside" or "external" and "inside" or "internal" are generally understood radially with respect to an axis A-A' of the flexible conduit, with "outside" or "external" meaning relatively farther radially from the axis A-A' and "inside" or "internal" meaning relatively closer radially to the axis A-A' of the flexible conduit. The terms "front" and "rear" are understood axially with respect to an axis A-A' of the conduit, with "front" meaning relatively farther from the midpoint of the conduit and closer to one of its ends, and "rear" meaning relatively closer to the midpoint of the conduit and farther from one of its ends. The midpoint of the conduit is the point on the conduit equidistant from its two ends.

[0039] A first flexible conduit 10 according to the invention is partially illustrated by figures 1 to 3.

[0040] The flexible conduit 10 has a central section 12 illustrated in part in Figure 1. It has, at each of the axial ends of the central section 12, an end fitting 14 (not visible in Figure 1) the relevant parts of which are shown in Figures 2 and 3.

[0041] Referring to Figure 1, the flexible pipe 10 defines a central passage 16 for the circulation of a fluid, advantageously a petroleum fluid. The central passage 16 extends along a central axis A-A', between the upstream and downstream ends of the flexible pipe 10. It opens through the fittings 14.

[0042] The flexible pipe 10 is intended to be laid across a body of water (not shown) in a fluid handling facility, particularly for hydrocarbons.

[0043] The body of water is, for example, a sea, a lake, or an ocean. The depth of the body of water at the location of the fluid processing facility is, for example, between 500 m and 4000 m.

[0044] The fluid handling installation comprises a surface assembly, including a floating assembly, and a bottom assembly (not shown), which are generally connected to each other by the flexible pipe 10.

[0045] Flexible driving 10 is preferably "unbonded" driving (designated by the English term "unbonded").

[0046] At least two adjacent layers of the flexible pipe 10 are free to move longitudinally relative to each other during pipe bending. Advantageously, all layers of the flexible pipe are free to move relative to each other.

[0047] Such conduct is described, for example, in the normative documents published by the American Petroleum Institute (API), API 17J, 5th edition - May 2024 and API RP 17B, 6th edition - May 2024.

[0048] As illustrated in Figure 1, the flexible conduit 10 delimits a plurality of concentric layers around the axis A-A', which extend continuously along the central section 12 to the end fittings 14 located at the ends of the conduit. According to the invention, the flexible conduit 10 comprises at least one first polymer sheath advantageously constituting a pressure sheath 20.

[0049] The flexible conduit 10 further comprises layers of tensile armor 24, 25 arranged externally with respect to the pressure sheath 20.

[0050] Advantageously, and depending on the desired use, the flexible pipe 10 further comprises an inner carcass 26 arranged inside the pressure sheath 20, a pressure arch 28, and possibly a collar, interposed between the pressure sheath 20 and the tensile armor layers 24, 25 and an outer sheath 30, intended for the protection of the flexible pipe 10.

[0051] As is known, the pressure sheath 20 is intended to hermetically contain the fluid transported in the passage 16. It is formed of polymer material, for example based on a polyolefin such as polyethylene, based on a polyamide such as PA11 or PA12, or based on a fluorinated polymer such as polyvinylidene fluoride (PVDF).

[0052] Alternatively, the pressure sleeve 20 is formed from a high-performance polymer such as PEK (polyetherketone), PEEK (polyetheretherketone), PEEKK (polyetheretherketoneketone), PEKK (polyetherketoneketone), PEKEKK (polyetherketoneetherketoneketone), PAI (polyamide-imide), PEI (polyether-imide), PSU (polysulfone), PPS11 (polyphenylsulfone), PES (polyethersulfone), PAS (polyarylsulfone), PPE (polyphenylene ether), PPS (polyphenylene sulfide), LCPs (liquid crystal polymers), PPA (polyphthalamide) and / or mixtures thereof, or in a mixture with PTFE (polytetrafluoroethylene) or PFPE (perfluoropolyether).

[0053] The thickness of the pressure sheath 20 is, for example, between 3 mm and 20 mm.

[0054] As can be seen in Figure 2, the pressure sheath 20 has an end region 27 arranged in the nozzle 14.

[0055] The frame 26, when present, is formed, for example, of a profiled metal strip, wound in a spiral. The turns of the strip are advantageously stapled together, which makes it possible to absorb radial crushing forces.

[0056] In this example, the carcass 26 is arranged inside the pressure sheath 20. The flexible pipe 10 is then designated by the English term "rough bore" because of the geometry of the carcass 26.

[0057] In an alternative configuration (not shown), the flexible pipe 10 lacks an internal casing 26 and is then referred to by the English term "smooth bore". The helical winding of the profiled metal strip forming the casing 26 has a short pitch, meaning that it has a helix angle around the axis A-A' of the pipe with an absolute value close to 90°, typically between 75° and 90°.

[0058] In this example, the pressure vault 28 is intended to absorb the radial forces related to the pressure within the pressure duct 20.

[0059] For example, it is formed of a profiled metal wire wound in a helical fashion around the sheath 20. The profiled wire generally has a complex geometry, notably in the shape of a Z, T, U, K, X or I, which allows the turns of the pressure arch 28 to be stapled together. Stapling the turns of the pressure arch 28 makes it possible to control the spacing between adjacent turns in order in particular to prevent creep of the pressure sheath 20 through the pressure arch 28 under the effect of the pressure prevailing inside the flexible pipe 10.

[0060] The pressure arch 28 is wound in a short-pitch helix around the pressure sheath 20, i.e. with a helix angle around the A-A' axis of the pipe of absolute value close to 90°, typically between 75° and 90°.

[0061] Optionally, a hoop not shown in Figure 1 surrounds the pressure arch 28. The hoop is also intended to take up the radial forces related to the pressure, in addition to the pressure arch 28. The hoop is for example formed of a metal wire of substantially rectangular cross-section wound in a short-pitch helix around the pressure arch 28. The turns of the hoop are not stapled together.

[0062] The pressure arch 28 and the fret when present each have an end region disposed in the end piece 14.

[0063] The flexible conduit 10 according to the invention comprises at least one layer of armor 24, 25 formed from a helical winding of at least one elongated armor element 29.

[0064] In the example shown in Figure 1, the flexible conduit 10 comprises a plurality of armor layers 24, 25, including a first internal armor layer 24, applied to the pressure arch 28 (or to the sheath 20 when the arch 28 is absent) and a second external armor layer 25 around which the outer sheath 30 is arranged.

[0065] Each layer of armor 24, 25 has longitudinal armor elements 29 wrapped at long pitch around the A-A' axis of the conduit.

[0066] By "long pitch winding", we mean that the absolute value of the helix angle is less than 60°, and is typically between 15° and 55°.

[0067] The armor elements 29 of a first layer 24 are generally wound at an opposite angle to the armor elements 29 of a second layer 25. Thus, if the winding angle of the armor elements 29 of the first layer 24 is equal to + a, a being between 15° and 55°, the winding angle of the armor elements 29 of the second layer of armor 25 arranged in contact with the first layer of armor 24 is for example - a, with a between 15° and 55°.

[0068] The armor elements 29 are for example formed by metal wires, or by composite ribbons, in particular composite ribbons reinforced by carbon fibers.

[0069] As can be seen in Figure 2, the armor elements 29 each have an end section 32 inserted into the end piece 14. The end section 32 extends to a free end disposed in the end piece 14. It advantageously has a helical or pseudo-helical trajectory with axis A-A' in the end piece 14.

[0070] The flexible conduit 10 advantageously includes wear-resistant layers 34 (see figure 2), interposed on the one hand between the pressure arch 28 and the first layer of internal reinforcement 24, and on the other hand between the two layers of reinforcement 24, 25.

[0071] Each anti-wear layer 34 is formed by helically winding a polymer strip typically between 0.5 mm and 4 mm thick. The function of each anti-wear layer 34 is to reduce friction between the metal wires or wear between the composite strips between which it is sandwiched.

[0072] The outer sheath 30 is designed to form a liquid-tight barrier from the outside of the flexible pipe to the inside. It is advantageously made of polymer material, in particular based on a polyolefin, such as polyethylene, polypropylene or polypropylene elastomer, based on a polyamide, such as PA11 or PA12, or based on a fluorinated polymer such as polyvinylidene fluoride (PVDF).

[0073] Alternatively, the outer sheath 30 is formed from a high-performance polymer such as PEK (polyetherketone), PEEK (polyetheretherketone), PEEKK (polyetheretherketoneketone), PEKK (polyetherketoneketone), PEKEKK (polyetherketoneetherketoneketone), PAI (polyamide-imide), PEI (polyether-imide), PSU (polysulfone), PPSU (polyphenylsulfone), PES (polyethersulfone), PAS (polyarylsulfone), PPE (polyphenylene ether), PPS (polyphenylene sulfide), LCPs (liquid crystal polymers), PPA (polyphthalamide) and / or mixtures thereof, or in a mixture with PTFE (polytetrafluoroethylene) or PFPE (perfluoropolyether).

[0074] The thickness of the outer sheath 30 is, for example, between 3 mm and 20 mm.

[0075] As can be seen in Figure 2, the outer sheath 30 has an end region 36 arranged in the tip 14.

[0076] Referring to Figure 2, each end piece 14 comprises, in addition to the end region 27 of the pressure sheath 20, the end region 36 of the outer sheath 30, and the end sections 32 of the armor elements 29, an end arch (not visible in Figure 2) and an outer connecting cover 51 projecting axially rearward from the end arch. The cover 51, together with the end arch, defines a chamber 52 for receiving the end sections 32 of the armor elements 29.

[0077] The end piece 14 further includes a front anchoring and sealing assembly (not visible) around the pressure sheath 20, an intermediate assembly 55 for radially retaining the armor elements 29 in the chamber 52, a rear sealing assembly 56 around the outer sheath 30 and a rear anchoring assembly 57 for the outer sheath 30 arranged at the rear of the rear sealing assembly 56.

[0078] In this example, the tip 14 further includes a solid filler material 58, such as a thermosetting polymer resin of the epoxy or araldite type. The solid filler material 58 is arranged in the chamber 52 around the end sections 32.

[0079] The end arch is intended to connect the flexible conduit 10 to another connection fitting 14 or to terminal equipment, advantageously via an end flange (not shown) or a fixing termination of the Grayloc® or Techlok® type.

[0080] The end arch has a central bore intended to receive the end region 27 of the pressure sheath 20 and to allow the flow of the fluid circulating through the central passage 16 to the outside of the flexible conduit 10.

[0081] The hood 51 has a tubular peripheral wall 70 extending around the axis A-A'. The peripheral wall 70 has a front edge (not visible) fixed to the end arch, radially away from the armor layers 24, 25 and a rear edge 74 extending axially rearward beyond the end arch.

[0082] The hood 51 delimits the chamber 52 radially outwards.

[0083] It defines a through-channel for injection (not visible) of fluid filling material intended to solidify in chamber 52, equipped with a plug 76A and at least one channel 76 for venting air out of chamber 52 during filling, offset axially along the central axis AA' relative to the injection channel.

[0084] In the example of Figures 2 and 5, the hood 51 further defines a test port 78, intended for testing the pressure tightness of the rear sealing assembly 56. The test port 78 includes a radial passage 80 through the hood 51, opening inwards between the air evacuation channel 76 and the rear edge 74 and a removable shutter 82 selectively closing the radial passage 80.

[0085] In the example illustrated in Figure 2, the rear edge 74 of the outer hood 51 has, from the rear and outside of the hood 51, towards the front and inside of the hood 51, a transverse rear face 90 for shimming the rear anchoring assembly 57, extending perpendicularly to the central axis A-A', a rear shoulder 92 and a front shoulder 94 for shimming the rear sealing assembly 56.

[0086] The radial passage 80 opens radially inwards between the front shoulder 94 and the rear shoulder 92, into a cylindrical peripheral surface 96 extending around the axis A-A', being directed towards the axis A-A'.

[0087] The intermediate radial retaining assembly 55 includes a radial retaining ring 100 for the end sections 32 of the armor elements 29 in a cylindrical configuration, and advantageously, a drainage collar 102 wedged on the retaining ring 100 at the rear thereof.

[0088] The retaining ring 100 surrounds the armor elements 29 to hold them against the pressure arch 28, or, where this pressure arch 28 is absent, against the pressure sheath 20. It is, for example, formed of several sections joined together to form a ring. Typically, the retaining ring 100 is in three parts.

[0089] Thus, between the rear edge 74 of the peripheral wall 70 of the hood 51 and the retaining ring 100, the armor elements 29 are held substantially within a cylindrical envelope. Between the retaining ring 100 and the front edge of the peripheral wall 70 of the hood 51, the armor elements 29 move away from the central axis AA' before moving towards the axis AA' to rest against the end arch.

[0090] The drainage collar 102 is positioned here opposite the channel 76, in front of the rear sealing assembly 56.

[0091] The rear sealing assembly 56 comprises, with reference to Figure 2, an outer support and locking ring 110, at least one external sealing gasket, preferably two external sealing gaskets 112A, 112B carried by the outer ring 110 to achieve a seal between the outer ring 110 and the cover 51, and at least one internal sealing gasket, preferably at least two internal sealing gaskets 114A, 114B carried by the outer ring 110 to achieve a seal between the outer region 36 of the outer sheath 30 and the outer ring 110.

[0092] The rear sealing assembly 56 further includes fixing members 116 of the outer ring 110 on the rear edge 74 of the peripheral wall 70 of the hood 51 and advantageously, a support cannula 118 of the outer region 36 of the outer sheath 30 inserted under the end region 36 of the outer sheath 30, opposite the outer ring 110.

[0093] The outer ring 110 is of revolution about the central axis A-A', as illustrated by Figure 3. It includes a base ring 120 carrying the sealing rings 112A, 112B; 114A, 114B and a radial fixing collar 122, projecting radially outwards from the base ring 120.

[0094] In the example shown in Figure 2, the outer ring 110 further includes a front skirt 124 extending the base ring 120 forwards and a rear skirt 126 extending the base ring 120 backwards.

[0095] As illustrated by figures 2 and 4, the ring 120 has an external cylindrical peripheral surface 130 and an internal cylindrical peripheral surface 132.

[0096] The external peripheral surface 130 applies against the peripheral wall 70 of the hood 51, at the level of the cylindrical peripheral surface 96.

[0097] The external peripheral surface 130 defines, for each external sealing joint 112A, 112B, a respective external annular housing 134A, 134B opening to the outside (see figure 4). The external annular housings 134A, 134B are axially offset from each other along the axis A-A'.

[0098] The external peripheral surface 130 has, in front of the external annular housings 134A, 134B, a front chamfer 136, inclined towards the axis AA' in the direction from back to front, to facilitate the introduction of the external ring 110 into the front shoulder 94.

[0099] The internal peripheral surface 132 applies to the external region 36 of the external sheath 30.

[0100] The internal peripheral surface 132 delimits, for each internal sealing joint 114A, 114B, a respective internal annular housing 138A, 138B opening radially towards the interior (see figure 4).

[0101] The internal annular housings 138A, 138B are axially offset from each other along the axis A-A'.

[0102] The base ring 120 further delimits a radial through passage 140 intended both for the pressure test of the rear sealing assembly 56, and for the lubrication of the external region 36 of the external sheath 30 during the assembly of the tip 14, as will be described below.

[0103] The radial passage 140 opens radially into the external peripheral surface 130 and into the internal peripheral surface 132. It preferably opens between the two external annular housings 134A, 134B and between the two internal annular housings 138A, 138B.

[0104] The radial collar 122 projects radially from the base ring 120, at the rear of the external annular housings 134A, 134B. As illustrated in Figure 3, it defines a plurality of holes 142 extending parallel to the axis AA' to receive each a fastening member 116. The holes 142 are advantageously oblong in a radial direction to facilitate assembly.

[0105] With reference to figure 2, the radial collar 122 has a shape complementary to that of the rear shoulder 92 to butt against the rear shoulder 92 and axially wedge the outer support ring 110 against the rear edge 74 of the hood 51.

[0106] The front skirt 124 projects axially forward from the base ring 120, extending the internal peripheral surface 132 flush with the front. Together with the base ring 120, it defines a forward step 144, complementary in shape to the front shoulder 94, to fit into the front shoulder 94.

[0107] The rear skirt 126 projects axially from the base ring 120, extending the internal peripheral surface 132 flush with the rear. Together with the base ring 120, it defines a rear step 146 for securing the rear anchor assembly 57.

[0108] The joints 112A, 112B; 114A, 114B are annular in shape. They each have a parallelepiped-shaped base 150 arranged in a respective housing 134A, 134B; 138A, 138B and a point 152 projecting out of the respective housing 134A, 134B; 138A, 138B.

[0109] With reference to Figures 2 and 4, each annular joint 112A, 112B; 114A, 114B comprises a deformable central region 153 defining the tip 152, a first rigidified front peripheral region 154A, disposed on one side of the central region 153 and a second rigidified rear peripheral region 154B, disposed on the other side of the central region 153.

[0110] The central region 153 is preferably formed of a deformable material, such as an elastomer. The elastomer is for example a fluoroelastomer, such as fluorocarbon (FKM) made from vinylidene fluoride (VDF or VF2) chosen for example from a copolymer of hexafluoropolyropylene (HFP) and VF2, a terpolymer of tetrafluoroethylene (or "TFE"), HFP, and VF2, a terpolymer of TFE, perfluoromethyl vinyl ether (or "PMVE") and VF2), a terpolymer of TFE, propylene and VF2 or a pentapolymer of TFE, HFP, ethylene, PMVE and VF2.

[0111] Alternatively, the fluoroelastomer is a perfluoroelastomer (FFKM), for example, a terpolymer of TFE, PMVE, and a third monomer enabling crosslinking. Alternatively, the fluoroelastomer is a fluorosilicone (FVMQ) or a propylene tetrafluoroethylene (FEPM) copolymer. Alternatively, or in addition, the central region 153 is made of nitrile rubber, in particular a butadiene acrylonitrile (NBR) copolymer and / or a hydrogenated butadiene acrylonitrile (HNBR) copolymer.

[0112] In this example, the first peripheral region 154A and the second peripheral region 154B are each formed by a stiffened ring 155 embedded in the deformable material forming the central region 153. The stiffened ring 155 is, for example, a spring wire, a rod, or a rope.

[0113] The stiffened ring 155 is for example formed of metal, a metal alloy or a material more rigid than the central region 153, for example a thermoplastic polymer, in particular of fibers.

[0114] The metal alloy is, for example, phosphor bronze. The fibers are, for example, synthetic artificial fibers made of polyester.

[0115] The more rigid material is, for example, made of PEK (polyetherketone), PEEK (polyetheretherketone), PEEKK (polyetheretherketoneketone), PEKK (polyetherketoneketone), PEKEKK (polyetherketoneetherketoneketone), or a fluoropolymer, such as polytetrafluoroethylene (PTFE). The thermoplastic polymer can be reinforced with fibers such as carbon fibers.

[0116] Alternatively, the stiffened ring 155 is made of a combination of metal and thermoplastic polymer, for example arranged coaxially. In particular, the stiffened ring 155 comprises coaxial coil springs, advantageously an internal coil spring made of metal, in particular stainless steel, and an external spring made of polymer, in particular PEEK (polyetheretherketone).

[0117] As an alternative, not shown, the stiffened ring 155 is a combination of a spring wire and a rod, the rod being arranged inside the spring wire.

[0118] The stiffened ring 155 is disposed in the vicinity of an inner surface of the annular joint 112A, 112B; 114A, 114B on either side of the tip 152.

[0119] The tip 152 is protruding at rest, as seen in figure 4, for the external sealing joints 112A, 112B. It has a rounded contour.

[0120] Each point 152 of an external sealing gasket 112A, 112B is applied, under radial compression, against the cylindrical peripheral surface 96 of the peripheral wall 70 between the shoulders 92, 94. Each point 152 of an internal sealing gasket 114A, 114B is applied, under radial compression, against the external region 36 of the external sheath 30. This fills the respective recesses 134A, 134B; 138A, 138B and generates a radial contact pressure between each gasket 112A, 112B; 114A, 114B, and the surface 96 or region 36 to which it is applied. In this example, the points 152 of the internal sealing joints 114A, 114B are further apart from each other along the axis A-A' than the points 152 of the external sealing joints 112A, 112B.

[0121] In the example shown in figures 2 to 4, in a median axial plane passing through the axis A-A', the cross-sectional area of ​​each external sealing joint 112A, 112B is less than the cross-sectional area of ​​each internal sealing joint 114A, 114B.

[0122] The fastening members 116 are mounted through the through holes 142 to fit into the rear edge 74 of the peripheral wall 70, in the bottom of the rear shoulder 92. They each have a head 160 projecting rearward relative to the radial collar 122.

[0123] The support cannula 118 includes a tubular support section 170, inserted inside the outer sheath 30, being positioned opposite the outer ring 110 and the rear anchoring assembly 57.

[0124] It includes, at the rear of the tubular support section 170, a tapered rear end 172, to facilitate its insertion between the end region 36 of the outer sheath 30 and the armor elements 29.

[0125] It also includes a peripheral front heel 174 which protrudes radially outwards from the tubular support section 170.

[0126] The front heel 174 is radially wedged against the outer ring 110, preferably at the level of the front skirt 124. Optionally, a sealing gasket is interposed between the outer ring 110 and the front heel 174, for example in a housing provided in the front heel 174.

[0127] The front heel 174 is also axially wedged at the front against the intermediate radial support assembly 55, in this example, against the drainage collar 102 and / or in the absence of a drainage collar 102, against the retaining ring 100.

[0128] This prevents the support cannula 118 from retracting under pressure. Therefore, the risk of loss of seal at the rear sealing assembly is considerably reduced.

[0129] The front heel 174 defines an axial stop for the end region 36 of the sheath 30 which is disposed between the tubular support section 170, the front heel 174 and the internal peripheral surface 132 of the outer ring 110.

[0130] Preferably, the edge of the end region 36 of the outer sheath 30 is applied against the front heel 174. The end region 36 of the outer sheath 30 completely fills the volume defined between the front heel 174, the tubular support section 170, and the outer ring 110. As illustrated in Figure 2, the rear anchoring assembly 57 is separate from the rear sealing assembly 56. It is positioned at the rear of the rear sealing assembly 56, bearing axially on the rear sealing assembly 56.

[0131] The rear anchoring assembly 57 includes a rear crimping ring 180 anchored in the end region 36 of the outer sheath 30 and a rear clamping flange 182 of the rear crimping ring 180 bearing against the transverse rear face 90.

[0132] The rear crimping ring 180 is interposed between an inclined surface 184 of the rear clamping flange 182 and the outer sheath 30. It is axially wedged against the rear skirt 126 of the outer ring 110.

[0133] The rear crimping ring 180 has a rear bulge 186 which is driven radially into the outer sheath 30 by wedge effect between the inclined surface 184 of the rear clamping flange 182 and the rear ring 180, when the rear clamping flange 182 is tightened against the transverse rear face 90.

[0134] The tubular support section 170 of the support cannula 118 extends opposite the rear bulge 186 so that the end region 36 of the outer sheath 30 is pinched between the cannula 118 and the rear crimping ring 180. This creates a reliable immobilization of the outer sheath 30, preventing its dislodging.

[0135] The rear clamping flange 182 is fixed against the transverse rear face 90. It has a ring 188 defining, towards the axis A-A', the inclined rear surface 184 and a fixing collar 190 projecting radially relative to the ring 188 away from the axis A-A' to apply to the transverse rear face 90.

[0136] The crown 188 has a front edge of complementary shape to the reverse gear 146 defined by the outer ring 110, to fit into the reverse gear 146.

[0137] The collar 190 defines a front housing 192, preferably annular, opening axially forward. The front housing 192 receives the projecting head 160 of each fastening member 116, when the rear clamping flange 182 is fixed to the rear edge 74 of the peripheral wall 70 of the hood 51.

[0138] The assembly of tip 14 will now be described.

[0139] Initially, the outer sheath 30 is partially cut to reveal the end sections 32 of the armor elements 29. The support cannula 118 is then put in place by being inserted between the armor elements 29 and the outer sheath 30.

[0140] The end region 36 of the outer sheath 30 is wedged against the front heel 174 of the cannula 118.

[0141] The drainage collar 102 is put in place by placing it in contact against the front heel 174. Then, the retaining ring 100 is mounted around the end sections 32 of the armor elements 29 to axially lock the drainage collar 102 and consequently, the support cannula 118.

[0142] As illustrated by Figure 4, after folding each of the armor elements 29 backwards to locally expose the layers located inside the armor layers 24, 25, the end arch of the nozzle (not visible) is connected to the core of the flexible pipe consisting of the inner carcass 26, the pressure sheath 20 and the pressure arch 28, ensuring in particular the placement of the crimping elements (not visible) of a front sealing assembly around the pressure sheath 20.

[0143] The two layers of armor 24, 25 are then unfolded forwards to position them around the end arch. Next, the distal front end of each end section 32 of each armor element 29 of the layers of armor 24, 25 is typically deformed into a hook shape. Finally, the peripheral wall 70 of the outer cover 51 is positioned opposite the end region 36 of the outer sheath 30. The front shoulder 94 and the rear shoulder 92 are then positioned opposite and radially offset from the end region 36 of the outer sheath 30.

[0144] The rear sealing assembly 56 is then put in place. For this purpose, the outer ring 110 is engaged around the end region 36 of the outer sheath 30. Advantageously, a mounting rod 194 is mounted axially through the through holes 142 to be fixed in the rear edge 74 of the peripheral wall 70. This allows the outer ring 110 to be advanced along the outer sheath 30, achieving the seal via the external sealing gaskets 112A, 112B and the internal sealing gaskets 114A, 114B.

[0145] To facilitate the advancement of the outer ring 110 parallel to the axis A-A', lubricant is placed on the end region 36 of the outer sleeve 30, in front of the front skirt 124. During the forward movement of the outer ring 110, the internal sealing gasket 114A located in front of the outer ring 110 scrapes the lubricant, which can subsequently cause excessive friction between the internal sealing gasket 114B located at the rear of the outer ring 110.

[0146] To overcome this problem following the advancement of the base ring 120 of the outer ring 110, lubricant is also added through the radial passage 140 to lubricate the end region 36 of the outer sheath 30 at the rear of the forwardmost internal sealing ring 114A and at the front of the rearmost internal sealing ring 114B. This facilitates the sliding of the outer ring 110 on the end region 36 of the outer sheath 30 and prevents damage to the end region 36 of the outer sheath 30 and the internal sealing ring 114B.

[0147] Furthermore, the presence of the chamfer 136 at the front of the base ring 120 facilitates the insertion of the base ring 120 into the front shoulder 94. The axial movement of the outer ring 110 continues until the step 144 at the front of the outer ring 110 is wedged against the bottom of the front shoulder 94. Simultaneously, the radial collar 122 is inserted against the bottom of the rear shoulder 92.

[0148] The mounting rod 194 is then removed, and replaced by fixing members 116 which are in turn inserted into the through holes 142 and into the bottom of the rear shoulder 92, as illustrated in Figure 5.

[0149] Then, the rear crimping ring 180 is in turn engaged around the end region 36 of the outer sheath 30. It is moved forward until it comes into contact with the rear skirt 126 of the outer ring 110.

[0150] Next, the rear clamping flange 182 is engaged around the rear crimping ring 180 by moving it axially towards the transverse face 90.

[0151] During this movement, the inclined surface 184 cooperates by wedge effect with the rear crimping ring 180 to push the rear bulge 186 radially towards the axis AA' and allow the pinching of the end region 36 of the outer sheath 30 between the rear bulge 186 and the tubular support section 170 of the support cannula 118.

[0152] Furthermore, during this movement, the protruding head 160 of each fastening element 116 is inserted into the front housing 192, which allows the complete application of the collar 190 of the rear flange 182 against the transverse rear face 90.

[0153] The rear flange 182 is then fixed against the transverse rear face 90, by means of fixing members 116.

[0154] Thanks to the presence of at least one external sealing gasket 112A, preferably several external sealing gaskets 112A, 112B and at least one internal sealing gasket 114A, preferably several internal sealing gaskets 114A, 114B, a very reliable seal is achieved on the one hand, between the peripheral wall 70 of the hood 51 and the outer ring 110 and on the other hand, between the outer ring 110 and the end region 36 of the outer sheath 30.

[0155] This sealing is achieved mainly using the seals 112A, 112B; 114A, 114B, by an axial displacement of the outer ring 110, independently of the axial anchoring of the outer sheath 30.

[0156] In this configuration with several seals 112A, 112B; 114A and 114B, combined with a removable shutter 82, a double sealing barrier is obtained which greatly limits, or even completely avoids, the risk of flooding of the annular space between the pressure sheath 20 and the external sheath 30 by water present outside the external sheath 30.

[0157] Furthermore, the mounting of a rear anchoring assembly 57 separate from the rear sealing assembly 56, the rear anchoring assembly 57 including a rear crimping ring 180, anchors the end region 36 of the outer sheath 30 relative to the outer cover 51, preventing its dislodging.

[0158] For this purpose, the end region 36 of the outer sheath 30 is confined at the front between the front heel 174, the tubular support section 170 and the outer ring 110 and is wedged at the rear by the rear bulge 186 of the rear crimping ring 180.

[0159] Thus, almost all the space between the front heel 174 of the support cannula 118 (for example more than 90% of this space, within tolerances), the tubular support section 170 and the outer ring 110 is occupied by the outer sheath 30, which prevents its creep.

[0160] This confinement also makes the sealing achieved by each of the internal sealing joints 114A, 114B very effective, since the tip 152 of each internal sealing joint 114A, 114B is noticeably compressed in contact with the external sheath 30. This is achieved without impacting the joints 112A and 112B, which are already very confined between the hood 51 and the base ring 120.

[0161] The support cannula 118 is axially immobilized, in particular by contact with the retaining ring 100 and / or with the drainage collar 102 itself in contact with the retaining ring 100, without gap.

[0162] This lack of possibility of axial displacement of the support cannula 118 is reinforced when the filling material 58 injected into the chamber 52 covers the retaining ring 100 and / or the drainage collar 102.

[0163] The axial blockage of the support cannula 118 is therefore very resistant, even if the external pressure applied to the outer sheath 30 at the rear end of the tip 14 increases significantly, which tends to push the support cannula 118 forward.

[0164] In the case illustrated in Figure 2, the radial passage 80 of the test port 78 opens between the internal sealing gaskets 114A, 114B. It is therefore in fluidic communication with each of the radial passages 140 delimited by the base ring 120. It is thus possible, once the assembly is complete, to test the sealing of the rear sealing assembly 56 via the test port 78 after removing the shutter 82. Advantageously, this can be done before crimping the rear ring 180.

[0165] Thus, a robust seal is achieved in a simple and reliable manner between the outer sheath 30 and the cap 51 of the nozzle 14, which greatly limits, or even completely avoids, the risk of flooding of the annular space between the pressure sheath 20 and the outer sheath 30 by water present outside the outer sheath 30.

[0166] In one variant, a single external seal 112A or a single internal seal 114A is used.

[0167] Figure 6 describes a variant of flexible conduit 10 in which an external protective sheath 196 is used in addition to and outside the external sheath 30. The external protective sheath 196 is for example made from a material defined above for the external sheath 30.

[0168] In this example, the rear clamping flange 182 extends rearward by means of a rear sleeve 198 for retaining the protective sheath 196, which applies to a clamping ring 200 arranged around the protective sheath 196 at the front end of the protective sheath 196.

[0169] In another variant of flexible conduit 10, shown in Figure 7, a thermal insulation layer 210 is arranged around the outer sheath 30, to thermally insulate the outer sheath 30.

[0170] The thermal insulation layer 210 is held in a rear extension 212 of the end cap 14 comprising a rear hood 214 extending rearward from the hood 51.

[0171] The rear hood 214 then rests on the collar 190 of the rear clamping ring 182. In this case, a common fixing member 116 is used to fix the outer ring 110 and the rear clamping flange 182 against the rear end 74 of the peripheral wall 70, internally with respect to the rear hood 214.

[0172] In one variant, the flexible conduit is a hybrid flexible conduit (or "HFP") comprising, within the outer sheath 30 and inside the reinforcement layer(s) 24, 25, a composite tubular reinforcement structure, the composite reinforcement structure having at least one reinforcement layer comprising a polymer matrix and reinforcing fibers. Such a flexible conduit is described, for example, in patent application WO2019 / 068757.

Claims

22 DEMANDS 1. End piece (14) of flexible fluid transport conduit (10), comprising: at least one end region (36) of an outer polymer sheath (30); end sections (32) of armor elements (29) of the flexible conduit (10), arranged inside the outer polymer sheath (30); an end arch, defining a central fluid circulation bore extending along a central axis (A-A'); a cover (51) defining with the end arch a chamber (52) for receiving the end sections (32) of armor elements (29) and the end region (36) of the outer sheath (30); a rear anchoring assembly (57) of the outer sheath (30) relative to the hood (51), characterized in that the end (14) comprises a rear sealing assembly (56) between the hood (51) and the outer sheath (30), the rear sealing assembly (56) comprising: an outer ring (110) disposed between the outer sheath (30) and the hood (51);at least one external sealing gasket (112A, 112B) carried by the outer ring (110) and interposed between the outer ring (110) and the cover (51); at least one internal sealing gasket (114A, 114B), carried by the outer ring (110), and interposed between the outer ring (110) and the outer sheath (30).

2. Tip (14) according to claim 1, wherein the rear sealing assembly (56) comprises at least two adjacent external sealing gaskets (112A, 112B) carried by the outer ring (110), and / or at least two adjacent internal sealing gaskets (114A, 114B) carried by the outer ring (110).

3. Tip (14) according to any one of claims 1 or 2, wherein the outer ring (110) defines, for each external sealing ring (112A, 112B), an external housing (134A, 134B), the external sealing ring (112A, 112B) comprising a base (150) received in the external housing (134A, 134B), and a tip (152) projecting out of the external housing (134A, 134B) to bear against the cover (51), and / or for each external sealing ring (112A, 112B), an internal housing (138A, 138B), the internal sealing ring (114A, 114B) comprising a base (150) received in the internal housing (138A, 138B), and a tip (152) protruding out of the internal housing (138A, 138B) to apply to the external sheath (30).

4. Tip (14) according to any one of the preceding claims, wherein the outer ring (110) comprises a base ring (120) and a collar of fixing (122), projecting radially outwards from the base ring (120), the fixing collar (122) being fixed to a rear edge (74) of the hood (51), the base ring (120) comprising an internal peripheral surface (132) carrying the internal sealing gasket(s) (114A, 114B) and an external peripheral surface (130) carrying the external sealing gasket(s) (112A, 112B).

5. Tip (14) according to claim 4, in which the base ring (120) defines a through passage (140) connecting the inner peripheral surface (132) to the outer peripheral surface (130) by passing through the base ring (120), the hood (51) advantageously comprising at least one test port (78) extending radially through the base ring (120), the test port (78) opening opposite the through passage (140).

6. End piece (14) according to any one of claims 4 or 5, wherein the outer peripheral surface (130) of the base ring (120) defines a front chamfer (136) disposed opposite the fixing collar (122).

7. Tip (14) according to any one of the preceding claims, wherein the rear sealing assembly (56) comprises a support cannula (118) inserted between the end sections (32) of the armor elements (29) and the end region (36) of the outer sheath (30), the end region (36) of the outer sheath (30) being wedged between the outer ring (110) and the support cannula (118).

8. Tip (14) according to claim 7, in which the support cannula (118) comprises a tubular support section (170), inserted under the outer sheath (30), and a front heel (174), projecting radially from the tubular support section (170), at the front of the support cannula (118), opposite a slice of the end region (36) of the outer sheath (30), the slice of the end region (36) of the outer sheath (30) being wedged against the front heel (174).

9. Tip (14) according to any one of claims 7 or 8, comprising a radial retaining ring (100) for the end sections (32) of the armor elements (29), applied to the end sections (32) of the armor elements (29) and / or a gas drainage collar (102), fixed axially around the end sections (32) of the armor elements (29), the support cannula (118) being arranged axially against the radial retaining ring (100) and / or against the gas drainage collar (102).

10. Tip (14) according to any one of the preceding claims, wherein the rear anchoring assembly (57) comprises a rear crimping ring (180) having a bulge (186) that fits into the end region (36) of the outer sheath (30), the rear anchoring assembly (57) comprising a rear clamping flange (182), having an inclined surface (184) of radial displacement of the rear crimping ring (180).

11. End cap (14) according to claim 10, in which the rear sealing assembly (56) comprises at least one fixing member (116) of the outer ring (110) on the hood (51) having a head (160) projecting rearward out of the outer ring (110), the rear clamping flange (182) defining a receiving housing (192) receiving the projecting head (160) when the rear clamping flange (182) is fixed on the rear edge (74) of the hood (51) by being applied against the outer ring (110).

12. Flexible fluid transport conduit (10), comprising a central section (12) having: at least one outer sheath (30) of polymer; armor elements (29) of at least one layer (24, 25) of tensile armor disposed in the outer sheath (30); the flexible conduit (10) comprising at least one end fitting (14) according to any one of the preceding claims, mounted at one end of the central section (12).

13. Method for mounting a flexible fluid transport pipe (10) fitting (14) comprising the following steps: - arrangement of at least one end region (36) of an outer polymer sheath (30), and end sections (32) of armor elements (29) of the flexible conduit (10), arranged inside the outer polymer sheath (30), between an end arch, defining a central fluid circulation bore extending along a central axis (A-A') and a hood (51) defining with the end arch a chamber (52) for receiving the end sections (32) of armor elements (29) and the end region (36) of the outer sheath (30); - installation of a rear anchoring assembly (57) of the outer sheath (30) relative to the cover (51), characterized by the mounting of a rear sealing assembly (56) between the cover (51) and the outer sheath (30), the rear sealing assembly (56) comprising: - an outer ring (110) disposed between the outer sheath (30) and the cover (51); - at least one external sealing gasket (112A, 112B) carried by the outer ring (110) and interposed between the outer ring (110) and the cover (51); - at least one internal sealing gasket (114A, 114B), carried by the outer ring (110), and interposed between the outer ring (110) and the outer sheath (30).

14. Method according to claim 13, wherein the assembly of the rear sealing assembly (56) is carried out before the installation of the rear anchoring assembly (57). 25 15. A method according to any one of claims 13 or 14, wherein the rear sealing assembly (56) comprises at least one front internal sealing gasket (114A) and at least one rear internal sealing gasket (114B) carried by the outer ring (110), the outer ring (110) comprising a base ring (120) comprising an inner peripheral surface (132) carrying each internal sealing gasket (114A, 114B) and an outer peripheral surface (130) carrying the or each outer sealing gasket (112A, 112B), the base ring (120) defining a through passage (140) connecting the inner peripheral surface (132) to the outer peripheral surface (130) by passing through the base ring (120) and opening between the front internal sealing gasket (114A) and the rear internal sealing gasket (114B),the assembly of the rear sealing assembly (56) comprising lubricating the end region of the outer sheath (30) in front of the front inner sealing gasket (114A), moving the outer ring (110) forward on the end region (36) of the outer sheath (30) and simultaneously adding lubricant to the end region (36) of the outer sheath (30) between the front inner sealing gasket (114A) and the rear inner sealing gasket (114B) via the through passage (140).

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