A flexible tube end fitting for conveying a fluid, a flexible tube for conveying a fluid, a method for assembling an end fitting, and a method for replacing an inner sheath in a flexible tube.

Abstract

END FITTING OF A FLEXIBLE TUBE FOR TRANSPORTING A FLUID, FLEXIBLE TUBE FOR TRANSPORTING A FLUID, METHOD FOR ASSEMBLING AN END FITTING AND METHOD FOR REPLACING AN INNER SHEATH IN A FLEXIBLE TUBE. The invention relates to an end fitting (14) of a flexible tube (14) for transporting a fluid comprising: - an end chamber (42) and an outer cover (44) fixed around the end chamber (42), - at least one front region (36) of an inner polymeric sheath (18), - at least end sections (40) of at least one tensile armor layer (24, 25) arranged around the inner polymeric sheath (18), - a front seal assembly (54) arranged around the front region (36) of the inner polymeric sheath (18).The front seal assembly (54) comprises a cannula (64) supporting at least part of the front region (36) of the inner polymer sheath (18) and an annular protrusion (66) disposed on an inner surface (48) of the end chamber (42). The front region (36) of the inner polymer sheath (18) is circumferentially clamped between at least one protrusion (66) and the cannula (64).

Description

"Flexible tube end fitting for transporting a fluid, flexible tube for transporting a fluid, method for assembling an end fitting and method for replacing an inner sheath in a flexible tube"

[001] The present invention relates to an end fitting for a flexible tube for transporting a fluid comprising: - an end chamber and an outer cover fixed around the end chamber and delimiting a receiving chamber, - at least one frontal region of an inner polymeric sheath defining a central passage for transporting the fluid, the central passage extending in a longitudinal direction, - at least end sections of at least one layer of tensile armor arranged around the inner polymer sheath, the end sections being arranged in the receiving chamber, - a front sealing assembly arranged around the front region of the inner polymer sheath.

[002] The pipe is, in particular, a flexible tube of a type that is not bonded (or “unbonded”) intended to transport a fluid, such as a fracturing fluid.

[003] Hydraulic fracturing, also referred to as "fracking," is a method that involves injecting a fracturing fluid at high pressure into a reservoir through a well to increase the reservoir's permeability and release oil and gas.

[004] Fracturing fluid consists primarily of water. The fluid may also comprise additional components such as sand and / or chemical components.

[005] Alternatively, the fluid transported in the flexible tube is oil and / or gas. Petition 870260014487, dated 02 / 13 / 2026, page 12 / 45 2 / 24

[006] The flexible tube is generally formed by a plurality of layers that are concentric and overlapping. It is considered “unbonded” within the scope and purpose of the present invention, since the tensile armor layers are free to move relative to each other during bending of the flexible tube, i.e., the tensile armor layers are not incorporated into a bonding material, such as an elastomer.

[007] The tube is in particular a plain bore tube. A tube is considered to be a “plain bore tube” when the innermost sheath of the tube that defines the passage for the fluid is made of a polymeric material. This type of flexible tube does not comprise an inner metal casing.

[008] The flexible pipe is generally laid on land, between a first surface assembly designed to collect the fluid used on land and a second surface assembly designed to distribute the fluid. For example, the flexible pipe is laid between a collector and a wellhead.

[009] The fluid is, for example, injected into a wellbore for hydraulic fracturing.

[0010] In this case, the flexible tube can have a short length between 1 m and 100 m, preferably between 1 m and 20 m.

[0011] In one variant, the flexible pipe is laid along a body of water, between a bottom assembly designed to collect the used fluid at the bottom of the body of water and a floating surface assembly designed to collect and distribute the fluid. The surface assembly may be a semi-submersible platform, an FPSO (floating production storage and offloading unit) or other unit.

[0012] Typically, flexible tubing comprises end fittings for connecting it to an adjacent structure, such as a manifold or wellhead, or to another flexible tubing.

[0013] The classic method used to seal the inner sheath of a Petition 870260014487, dated 02 / 13 / 2026, page 13 / 45 3 / 24 flexible non-glued tubing is crimped between an inner and an outer metal layer.

[0014] The inner metallic layer provides mechanical support to the inner sheath to allow proper contact and withstand plastic deformation of the inner sheath.

[0015] The outer metal layer is typically a monocone penetrating the inner polymer sheath. Compression of the inner sheath prevents fluid and gas migration and provides a leak-proof barrier. The monocone is pressed down and plastically deformed by pushing it forward on a machined slope in the end fitting chamber. This is done by crimping a flange in the chamber that allows the forces necessary for the plastic deformation of the monocone and the inner sheath to be created. A second leakage path between the chamber and the monocone is sealed by metal-to-metal contact that remains energized by the crimping flange.

[0016] Metal-to-metal sealing requires that the contact surfaces have a proper, scratch-free finish. Therefore, great care is needed during the end fitting assembly process. Furthermore, due to the fact that the flange crimping operation is performed from the rear of the chamber, there is some interference with the flexible tube fittings which must be recessed to allow proper access. This leads to an overall elongation of the end fitting.

[0017] One objective of the invention is to overcome these drawbacks and provide an end fitting that allows good fluid tightness by involving fewer elements in order to reduce the length and weight of the end fitting.

[0018] To that end, the object of the invention relates to an end fitting of the aforementioned type, in which the front sealing assembly Petition 870260014487, dated 02 / 13 / 2026, page 14 / 45 4 / 24 comprises a cannula supporting at least part of the frontal region of the inner polymer sheath and at least one annular protrusion disposed on an inner surface of the end chamber protruding towards the central passage, with at least part of the frontal region of the inner polymer sheath being circumferentially squeezed between the at least one protrusion and the cannula.

[0019] The end fitting according to the invention may comprise one or more of the following features, considered individually or in any technically feasible combination: - at least one protrusion is integral with the end chamber; - at least one protrusion is an annular ring; - at least part of the frontal region of the inner polymeric sheath is plastically deformed by the protrusion; - The front seal assembly comprises two annular protrusions separated along the longitudinal direction; - The end fitting comprises a defined test orifice in the end chamber to check the sealing of an internal space bounded by the inner surface of the end chamber and an outer surface of the inner polymer sheath, between the annular protrusions; - The front seal assembly comprises a retention element to keep the cannula fixed to the end chamber; - The inner polymer sheath is a polymer pressure sheath designed to hermetically confine the fluid transported through the central passage, the polymer pressure sheath advantageously having a thickness between 5 mm and 20 mm; - the end fitting further comprises a front region of a pressure sleeve, the inner polymeric sleeve being a sheath Petition 870260014487, dated 02 / 13 / 2026, page 15 / 45 5 / 24 protective polymeric sheath designed to protect the pressure sleeve, the pressure sleeve being arranged around the protective polymeric sheath; - The end fitting also includes an intermediate sealing assembly arranged around the front region of the pressure sleeve.

[0020] The object of the invention also refers to a flexible tube comprising: - at least one internal polymeric sheath defining a central passage for transporting the fluid, the central passage extending in a longitudinal direction, - at least one layer of tensile armor arranged around the inner polymer sheath, and - an end fitting as described above.

[0021] The flexible tube may comprise one or more of the following features, considered individually or in any technically feasible combination: - the flexible tube comprises an end fitting as described above and a pressure sheath designed to hermetically confine the fluid carried through the central passage, the inner polymer sheath being formed by the pressure sheath; - The flexible tube comprises an end fitting as described above, a pressure sheath and a protective polymer sheath designed to protect the pressure sheath and intended to hermetically confine the fluid carried by the central passage, the pressure sheath being arranged around the protective polymer sheath, the inner sheath being formed by the protective polymer sheath.

[0022] The invention also relates to a method for assembling an end fitting as described above, the method comprising the following steps: Petition 870260014487, dated 02 / 13 / 2026, page 16 / 45 6 / 24 - provide a flexible tube, - provide an end chamber comprising at least one annular protrusion disposed on the inner surface of the end chamber, with at least one protrusion projecting towards the central passage, - fixation of the end chamber in at least part of the frontal region of the inner sheath, - provide a cannula, - Insert the cannula to support at least part of the frontal region of the inner sheath, circumferentially tightening said at least part of the frontal region of the inner sheath between at least one annular protrusion and the cannula.

[0023] Finally, the object of the invention relates to a method for replacing an inner sheath in a flexible tube as described above, the method comprising the following steps: - remove the cannula, - remove the inner sheath of the flexible tube from one end of the end fitting, - Insert a new inner sheath through the end of the end fitting. - Insert a new cannula into the inner sheath to circumferentially tighten at least part of the front region of the inner sheath that lies between at least one protrusion of the front seal assembly and the cannula.

[0024] The invention will be better understood by reading the following description, given only by way of example, and with reference to the accompanying drawings in which: Figure 1 is a partially disassembled perspective view. Petition 870260014487, dated 02 / 13 / 2026, page 17 / 45 7 / 24 of a section of a flexible tube according to the invention; Figure 2 is a schematic view, taken along a median cross-section, of an end fitting according to a first embodiment of the invention; Figure 3 is a schematic view of one step in a method for replacing a protective polymer sheath according to the invention. Figure 4 is a schematic view, taken along a median cross-section, of an end fitting according to a second embodiment of the invention; Figure 5 is a schematic view, taken along a median cross-section, of an end fitting according to the third embodiment of the invention; Figure 6 is a schematic view, taken along a median cross-section, of an end fitting according to a fourth embodiment of the invention; and Figure 7 is a schematic view, taken along a median cross-section, of an end fitting according to a fifth embodiment of the invention.

[0025] Hereafter, the terms “external” and “internal” should generally be understood in a radial manner with respect to a longitudinal direction (X-X') of the tube. The term “external” should be understood as being relatively farther radially from the longitudinal direction (X-X') and the term “internal” should be understood as being relatively closer radially to the longitudinal direction (X-X') of the tube.

[0026] A first flexible tube (10) according to the invention is partially shown in Figure 1.

[0027] The flexible tube (10) comprises a central section (12) shown in part in Figure 1. Petition 870260014487, dated 02 / 13 / 2026, page 18 / 45 8 / 24

[0028] With reference to Figure 1, the flexible tube (10) delimits a central passage (16) for fluid circulation, advantageously a fluid for hydraulic fracturing. The central passage (16) extends along the longitudinal direction (X-X'), between the upstream end and the downstream end of the flexible tube (10).

[0029] The flexible tube (10) is intended, for example, for the circulation of a fluid under pressure for hydraulic fracturing.

[0030] The flexible pipe is typically laid on land between a wellhead and a manifold.

[0031] The fluid is, for example, injected into a wellbore in the case of hydraulic fracturing.

[0032] Hydraulic fracturing, also referred to as “fracking”, is a method that involves injecting a fracturing fluid at high pressure, such as 1000 bar (15000 psi), into a reservoir through a wellbore to increase reservoir permeability and release oil and gas.

[0033] Fracturing fluid consists primarily of water. The fluid may include additional elements such as sand and / or chemical components.

[0034] The fluid temperature is the ambient temperature of the flexible tube. It is generally between -20 °C and (60) °C.

[0035] In one variant, the flexible pipe (10) is intended to be laid along a body of water (not shown) and in a fluid prospecting and exploration facility, in particular hydrocarbons.

[0036] The body of water is, for example, a sea, a lake or an ocean. The depth of the body of water in the area of ​​the fluid prospecting and exploration facility is, for example, between 500 m and 3,000 m.

[0037] The fluid exploration and prospecting installation includes a surface assembly, in particular a floating assembly and an assembly of Petition 870260014487, dated 02 / 13 / 2026, p. 19 / 45 9 / 24 bottom (not shown) which are usually connected to each other by a flexible tube (10).

[0038] The flexible tube (10) is preferably a tube that is “unbonded” (referred to by the term “unbonded” according to accepted English terminology).

[0039] At least two layers of tensile armor of the flexible tube (10) are free to move longitudinally relative to each other after bending or flexing of the tube. Advantageously, all layers of the flexible tube (10) are free to move relative to each other. In one variant, the flexible tube (10) is a bonded flexible tube.

[0040] The flexible tube (10) is in particular a smooth bore tube as described below. A tube is considered to be a “smooth bore tube” when the innermost sheath of the tube that defines the passage for the fluid is made of a polymeric material. In this case, the flexible tube (10) does not comprise an inner metal casing.

[0041] The flexible tube (10) comprises a plurality of concentric layers around the longitudinal direction (X-X'), which extends continuously along the central section (12) between the upstream end and the downstream end of the flexible tube (10), up to the end fittings (14) located at the ends of the flexible tube (10).

[0042] According to the invention, the flexible tube (10) comprises at least one inner sheath (18) made of a polymer-based material and designed to be used to tightly confine the fluid being transported in the central passage (16).

[0043] As will be described below, in a first embodiment of the invention (Figures 1 and 2), the inner sheath (18) is formed by the pressure sheath (20).

[0044] In a second embodiment of the invention (Figure 4), the inner sheath (18) is formed by a protective polymeric sheath (34) Petition 870260014487, dated 02 / 13 / 2026, page 20 / 45 10 / 24 arranged internally to the pressure sleeve (20).

[0045] Returning to the first embodiment of the invention of Figures 1 and 2, the flexible tube (10) further comprises at least one layer of tensile armor (24, 25) disposed externally in relation to the pressure sheath (20).

[0046] Advantageously, and according to the desired use, the flexible tube (10) further comprises a pressure chamber (30) interposed between the pressure sheath (20) and the tensile armor layer or layers (24, 25) and an outer sheath (32), designed to ensure the protection of the flexible tube (10).

[0047] Preferably, the flexible tube (10) further comprises a housing (37) disposed externally to the outer sheath (32).

[0048] In a known manner, the pressure sheath (20) is formed from polymeric 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).

[0049] In a variant, the pressure sheath (20) is formed from an elastomer or polyurethane.

[0050] The thickness of the pressure sheath (20) is, for example, between 5 mm and 20 mm.

[0051] In the example in Figure 1, the pressure chamber (30) is designed to absorb the forces related to the prevailing pressure inside the pressure sheath (20). It is, for example, formed by a profiled metal wire wound helically around the sheath (20). The profiled wire usually has a complex geometry, in particular having a Z, T, U, K, X, S or I shape.

[0052] The pressure chamber (30) is helically wound with a short pitch around the pressure sheath (20), i.e., with an angle of Petition 870260014487, dated 02 / 13 / 2026, page 21 / 45 11 / 24 propeller having an absolute value close to 90°, typically between 75° and 90°.

[0053] The flexible tube (10) according to the invention comprises at least one armor layer (24, 25) formed by a helical winding of at least one elongated armor element (wires) (38).

[0054] In the example shown in Figure 1, the flexible tube (10) includes a plurality of reinforcing layers (24, 25), in particular an inner reinforcing layer (24), applied to the pressure chamber (30) and an outer reinforcing layer (25) around which the outer sheath (32) is arranged. The reinforcing layers (24, 25) allow it to withstand the deformation created by the pressurized fluid circulating inside the flexible tube.

[0055] Each layer of reinforcement (24, 25) includes longitudinal reinforcement elements (38) wrapped with a long pitch around the longitudinal direction (X-X') of the tube (10).

[0056] The term “long pitch wound” is used to indicate that the absolute value of the helix angle is less than (60)° and is normally between 25° and 55°.

[0057] The reinforcing armor elements (38) of a first layer of reinforcement (24) are generally wound at an angle in the opposite direction with respect to the reinforcing armor element (38) of a second layer of reinforcement (25). Thus, if the winding angle of the reinforcing armor element (38) of the first layer of reinforcement (24) is equal to +α, with α between 10° and (60)°, in particular between 25° and 55°, the winding angle of the reinforcing armor element (38) of the second layer of reinforcement (25) disposed in contact with the first layer of reinforcement (24) is for example -α, with α between 10° and (60)°, in particular between 25° and 55°. Petition 870260014487, dated 02 / 13 / 2026, page 22 / 45 12 / 24

[0058] Advantageously, and according to the intended use, each reinforcing armor layer (24, 25) is provided with at least one anti-wear layer (not shown) on which the layer (24, 25) is supported. The anti-wear strip (not shown) is made, for example, of plastic.

[0059] The reinforcing armor elements (38) are, for example, made of metal wire, namely steel wires, or of composite material tape, for example carbon fiber reinforced tape.

[0060] The reinforcing armor elements (38) comprise end sections (40) inserted into the end fitting (14). Each end section (40) comprises a free end disposed in the end fitting (14).

[0061] The outer sheath (32) is intended to prevent fluid permeation from the outside of the flexible tube (10) to the inside. It is advantageously made of a polymeric material, in particular based on a polyolefin, such as polyethylene or polypropylene, based on a polyamide, such as PA11 or PA12, or based on a fluorinated polymer, such as polyvinylidene fluoride (PVDF).

[0062] The thickness of the outer sheath (32) is, for example, between 5 mm and 15 mm.

[0063] The carcass (37), when present, is formed, for example, by a profiled metal strip that is spirally wound. The spiral windings of the strip are advantageously interconnected. The function of the carcass is to protect the outer sheath (32) from tears, wear, abrasion and other external damage.

[0064] The helical winding of the profiled sheet metal that forms the housing (37) is short pitch, that is, it has a helix angle with an absolute value close to 90°, typically between 75° and 90°, more particularly between 75° and 88°.

[0065] As shown for example in Figure 2, in addition to the region Petition 870260014487, dated 02 / 13 / 2026, page 23 / 45 13 / 24 front (36) of the inner sheath (18), the end sections (40) of the reinforcement layers (24, 25), the end fitting (14) comprises an end chamber (42) and an outer cover (44) around the end chamber (42). The outer cover (44) projects axially backward from the end chamber (42). The outer cover (44) delimits with the end chamber (42) and the pressure chamber (30), a receiving chamber (46) which receives the end sections (40) of the reinforcement layers (24, 25).

[0066] The end chamber (42) defines an inner surface (48) in contact with the front region (36) of the inner sheath (18).

[0067] The inner surface (48) comprises a front longitudinal part (50) that extends along the direction (X-X').

[0068] The end fitting (14) further comprises a front seal assembly (54) disposed around the front region (36) of the inner sheath (18). In the embodiment of Figure 1, the front seal assembly (54) is disposed around the pressure sheath (20). The end fitting (14) further comprises a rear seal assembly (not shown) disposed around the outer sheath (32).

[0069] The end chamber (42) comprises a front region (43) comprising an end flange (45), a rear region (47), covered by the outer cover (44) and an intermediate region (49) connecting the front region (43) to the rear region (47).

[0070] In this example, the end chamber (42) is intended to connect the flexible tube (10) to another end fitting (14) or to a terminal device, advantageously by the end flange (45).

[0071] The outer cover (44) comprises a peripheral tubular wall (58) extending around in the longitudinal direction (X-X'). The peripheral wall (58) has a rear edge (60) extending axially to the rear. Petition 870260014487, dated 02 / 13 / 2026, p. 24 / 45 14 / 24 beyond the end chamber (42).

[0072] The outer cover (44) delimits the receiving chamber (46) radially outwards. The end chamber (42) and a front region (62) of the pressure sheath (20) delimit the receiving chamber (46) radially inwards.

[0073] The receiving chamber (46) is advantageously filled with a filling material intended to anchor the end sections (40) of the reinforcement elements (38) within the receiving chamber (46).

[0074] The filler material is, for example, a thermosetting resin, such as an epoxy resin or a thermoplastic resin.

[0075] The front sealing assembly (54) is arranged in front of the end fitting (14). It is spaced longitudinally from the receiving chamber (46), in front of the receiving chamber (46), in the front region (43).

[0076] The front seal assembly (54) comprises a cannula (64) supporting at least part of the front region (36) of the pressure sheath (20) and an annular projection (66) disposed on the inner surface (48) of the end chamber (42) and projecting towards the central passage (16) and more particularly disposed on the front part (50) of the inner surface (48) of the end chamber (42).

[0077] The front region (36) of the inner sheath (18) is circumferentially tightened between the protrusion (66) and the cannula (64).

[0078] Preferably, the protrusion (66) is integral with the end chamber (42).

[0079] In one variant, the protrusion (66) is an annular element fixed to the inner surface (48) of the end chamber (42).

[0080] Preferably, the protrusion (66) extends beyond the inner surface (48) of the end chamber (42) towards the central passage (16) to a distance between 50 mm and 300 mm. Petition 870260014487, dated 02 / 13 / 2026, page 25 / 45 15 / 24

[0081] The front region (36) of the pressure sheath (20) is plastically deformed by the protrusion (66).

[0082] The cannula (64) has a general tubular shape. The cannula (64) comprises a cylindrical front portion (68) and a truncated cone-shaped rear portion (70) connected to the front portion (68).

[0083] The front portion (68) of the cannula (64) is positioned facing the front part (50) of the inner surface (48) of the end chamber (42).

[0084] An outer surface (72) of the front portion (68) of the cannula (64) and the front part (50) of the inner surface (48) of the end chamber (42) are substantially concentric.

[0085] The rear portion (70) of the cannula (66) allows a progressive radial spread of the front region (36) of the pressure sheath (20) until the pressure sheath (20) covers the front portion (68) of the cannula (64).

[0086] The cannula (64) has a longitudinal length between 100 mm and 400 mm.

[0087] The protrusion (66) is positioned facing the front portion (68) of the cannula (64).

[0088] The cannula (64) is made of metal. For example, the cannula (64) is made of carbon or stainless steel.

[0089] In addition, the end fitting (14) may further comprise a longitudinal restraining element (not shown) for restraining the cannula (64) to the end chamber (42).

[0090] The rear sealing assembly (not shown) comprises, for example, a rear crimping ring for crimping the outer sheath and a rear crimping ring fixing flange, fixed to the outer cover (44).

[0091] A method for assembling an end fitting (14) of Petition 870260014487, dated 02 / 13 / 2026, page 26 / 45 The 16 / 24 type mentioned above will now be described.

[0092] Initially, the method comprises providing a flexible tube (10). A front region (36) of the inner sheath (18) is removed from the pressure chamber (30), the first and second armor layers (24, 25), the outer sheath (32) and the casing (37).

[0093] In the embodiment of Figure 2, the end sections (40) of the reinforcement layers (24, 25) are then prepared to be received in the receiving chamber (46). The end sections (40) are dispensed from the front region (36) of the pressure sheath (20) and the pressure chamber (30).

[0094] Thus, the method comprises providing an end chamber (42) as described above and fixing said end chamber (42) onto at least part of the front region (36) of the pressure sheath (20).

[0095] The method comprises providing a cannula (64) as described above.

[0096] The cannula (64) is then inserted into the central passage (16) to support the front part (36) of the pressure sheath (20).

[0097] For example, the cannula (64) is pushed by a tool that can be supported by the end chamber (42) which will act as a reaction point.

[0098] The pressure sheath (20) is then tightened circumferentially between the protrusion (66) and the cannula (64).

[0099] When the cannula (64) is in place, the cannula (64) is not subject to any displacement thanks to the compression forces applied by the rear portion (70) of the cannula (64) to the pressure sheath (20) during assembly.

[00100] The outer cover (44) is then placed and fixed to the chamber. Petition 870260014487, dated 02 / 13 / 2026, page 27 / 45 17 / 24 end (42).

[00101] Finally, the rear sealing assembly is secured and activated by attaching to the outer cover (44).

[00102] The receiving chamber (46) is then filled with a filler material such as an epoxy resin or a thermoplastic resin.

[00103] Alternatively, the receiving chamber (46) is filled with a filling material before insertion of the cannula.

[00104] A method for replacing a pressure sheath (20) of a flexible tube (10) as described above will be described.

[00105] The method applies when the pressure sheath (20) is damaged chemically or mechanically.

[00106] First, the method involves removing the cannula (64). This allows the pressure sheath (20) to be released from the end termination of the flexible tube (10).

[00107] A first method of removing the cannula (64) consists of extracting the cannula (64) by mechanical means. For example, grooves or holes are made in the cannula (64) to allow the engagement of a mechanical or hydraulic extraction tool. Activation of the tool disengages the cannula (64) and extracts the cannula (64) from the end fitting (14).

[00108] If the cannula (64) is severely damaged, longitudinal cuts are made along the entire length of the cannula (64) to divide it into sections, for example, two, preferably three or more sections. This allows the compressive forces exerted by the pressure sheath to be released and provides sufficient clearance to remove the cannula (64) by sections.

[00109] The risk of damaging the end fitting (14) is limited, as the pressure sleeve (20) protects the inner surface (48) of the tool's end chamber (42).

[00110] Another way to remove the cannula (64) consists of placing Petition 870260014487, dated 02 / 13 / 2026, page 28 / 45 18 / 24 a watertight packer is placed on the cannula (64). The flexible tube (10) is then filled with water and pressurized to push the cannula (64) out.

[00111] The method then comprises extracting the pressure sheath (20) from the flexible tube (10) at one end of the end fitting (14).

[00112] One first way of extracting the pressure sheath (20) consists of inserting a thin cannula between an outer surface of the pressure sheath (20) and the end fitting (14). This cannula acts as a support element for a tool that expands over it. The tool, such as a shutter or a mechanical expander, is then able to grip the pressure sheath (20).

[00113] Two tools are installed at both ends of the flexible tube (10) to exert tension on the pressure sheath (20) and decrease the diameter of the pressure sheath (20). Controlled tension winches can be used at both ends of the flexible tube to control the tension exerted on the pressure sheath (20). Alternatively, a stop is used on the release side and a brake system is used on the other side for short tube sections.

[00114] In a second variant, a tool comprising multiple cutting blades can be pulled through the flexible tube (10) to segment the pressure sheath (20). Then, the pressure sheath (20) can be easily released segment by segment.

[00115] The method for replacing the pressure sheath (20) then comprises inserting a new pressure sheath (20).

[00116] One first way of inserting the new pressure sheath (20) consists of bending the pressure sheath (20) into a U shape to create a smaller artificial diameter. The collapsed pressure sheath (20) is inserted along the entire length of the flexible tube (10). Then, mechanical reshaping, for example using a tube scraper (pig), allows the sheath to be given Petition 870260014487, dated 02 / 13 / 2026, page 29 / 45 19 / 24 pressure (20) its original tubular shape.

[00117] In this variant, hydraulic reshaping is used. The pressure sheath (20) is filled with a pressurized liquid to give it its original tubular shape.

[00118] An alternative way to insert the new pressure sheath (20) is shown in Figure 3. The pressure sheath (20) is elongated using a die or roller box (92) at one end of the flexible tube (10) corresponding to the insertion point. A tensile force is applied to one end of the pressure sheath (20). For example, a winch (94) is attached to the end of the pressure sheath (20). By applying a tensile force to the pressure sheath (20), the pressure sheath (20) elongates and reduces in diameter. The die or roller box (92) acts as a breaking force working against the winch (94).

[00119] Once the pressure sheath (20) is placed inside the flexible tube (10), the tension is released and the pressure sheath (20) returns to its original diameter.

[00120] In a variant, a lubricant is applied to the pressure sheath (20) and can be used to assist insertion of the pressure sheath (20) into the flexible tube (10).

[00121] In a variant, a tube scraper is used to pull the pressure sheath (20) into the flexible tube.

[00122] Another alternative way of inserting the new pressure sheath (20) comprises inserting a pressure sheath (20) with a smaller diameter compared to the inner diameter of the pressure chamber (30). Then, hydraulic expansion of the pressure sheath (20) is performed using hydrostatic pressure. In addition, heating the pressure sheath (20) can facilitate radial expansion of the sheath (20).

[00123] The end fitting (14) according to the invention Petition 870260014487, dated 02 / 13 / 2026, pp. 30 / 45 20 / 24 is particularly advantageous because by performing the crimping operation from the front end of the end fitting (14) with a defined protrusion (66) in the end chamber (42), it allows reducing the number of elements in the end fitting (14), reducing the size and weight of the end fitting (14).

[00124] A second embodiment of an end fitting (14) according to the invention is shown in Figure 4. The description of this embodiment is made by difference in comparison with the first embodiment.

[00125] In this embodiment, the flexible tube (10) comprises both a protective polymer sheath (34) and a pressure sheath (20) disposed externally to the protective polymer sheath (34).

[00126] The protective polymer sheath (34) is arranged on an inner surface of the pressure sheath (20).

[00127] The protective polymer sheath (34) protects the pressure sheath (20) from the fluid circulating in the central passage (16). The protective polymer sheath (34) is particularly advantageous for protecting the inner surface of the pressure sheath (20) in the event that the fluid circulating in the central passage (16) includes elements such as sand grains that could damage the inner surface of the pressure sheath (20).

[00128] The protective polymeric sheath (34) is formed, for example, from a polymeric material, for example, based on a polyolefin, such as polyethylene or based on a polyamide, such as PA11 or PA12 or based on a fluorinated polymer, such as polyvinylidene fluoride (PVDF). Alternatively, the protective polymeric sheath (34) is formed from elastomer-based materials or a polyurethane.

[00129] The thickness of the protective polymer sheath (34) is, for example, between 5 mm and 30 mm. Petition 870260014487, dated 02 / 13 / 2026, page 31 / 45 21 / 24

[00130] The protective polymer sheath (34) comprises a front region (36) inserted into the end fitting (14).

[00131] The protective polymer sheath (34) can be either coextruded with the pressure sheath (20) or manufactured separately.

[00132] In this embodiment, the inner polymer sheath (18) is formed by the protective polymer sheath (34).

[00133] Therefore, as visible in Figure 4, the front sealing assembly (54) is arranged around the protective polymeric sheath (34).

[00134] The end fitting further comprises an intermediate sealing assembly (56) around the pressure sleeve (20).

[00135] The intermediate sealing assembly (56) comprises an intermediate crimping flange (78), an intermediate crimping ring (80) and an intermediate support cannula (82) interposed between the protective polymer sheath (34) and the pressure sheath (20).

[00136] The intermediate crimping ring (80) is interposed between a rear surface (84) of the intermediate crimping flange (78) and the pressure sleeve (20).

[00137] The pressure sheath (20) rests on the intermediate support cannula (82).

[00138] Preferably, as illustrated in Figure 4, the end fitting (14) comprises a test hole (76) set in the end chamber (42) and disposed between the protrusion (66) and the intermediate sealing assembly (56). The test hole (76) allows testing the crimping effectiveness and therefore the tightness of the end fitting (14). Here the test port (76) is located in the intermediate region (49).

[00139] In this embodiment, the test port (76) allows checking the integrity of the flexible tube (10). In fact, for example, it allows measuring the pressure between the pressure sheath (20) and the protective polymer sheath (34). Petition 870260014487, dated 02 / 13 / 2026, pp. 32 / 45 22 / 24 When the protective polymer sheath (34) is damaged, the pressure on the test port (76) increases, indicating that the protective polymer sheath must be changed.

[00140] The method for assembling an end fitting (14) according to the second embodiment further comprises fixing the intermediate sealing assembly (56) and activating it by fixing it in the end chamber (42).

[00141] The various ways of removing the protective polymer sheath (34) or inserting a new protective polymer sheath (34) are similar to those described above for the pressure sheath (20) in the first embodiment.

[00142] Furthermore, a second way to extract the protective polymer sheath (34) is to deform the protective polymer sheath (34) into a collapsed U shape. This can be done by pressurizing the annular space defined between the pressure sheath (20) and the protective polymer sheath (34) to collapse the protective polymer sheath (34).

[00143] A third embodiment of an end fitting (14) according to the invention is shown in Figure 5. The description of this embodiment is made by difference in comparison with the first embodiment.

[00144] In this embodiment, within the receiving chamber (46), the end fitting (14) further comprises an inner ring (86) on which the end sections (40) of the first layer of reinforcement (24) rest externally, an intermediate ring (88) interposed between the end sections (40) of the first layer of reinforcement (24) and the end sections (40) of the second layer of reinforcement (25) and an outer ring (90) disposed in external support on the end sections (40) of the second layer of reinforcement (25). Petition 870260014487, dated 02 / 13 / 2026, pp. 33 / 45 23 / 24

[00145] The inner surface (48) of the end chamber (42) comprises a longitudinal front part (50) connected to a rear part (96). The rear part (96) extends along a direction that intersects the longitudinal direction (X-X').

[00146] The rear portion (70) of the cannula (64) is positioned facing the rear portion (96) of the inner surface (48) of the end chamber (42).

[00147] An outer surface (72) of the front portion (68) of the cannula (64) and the front part (50) of the inner surface (48) of the end chamber (42) are substantially concentric.

[00148] An outer surface (74) of the rear portion (70) of the cannula (64) and the rear portion (96) of the inner surface (48) of the end chamber (42) are substantially concentric.

[00149] A fourth embodiment of the invention is shown in Figure 6. This embodiment is described by differences compared with the embodiment in Figure 5.

[00150] The end fitting (14) further comprises a longitudinal retaining element (98) for restricting the cannula (64) to the end chamber (42). The retaining element (98) is, for example, a pin (100) inserted through the cannula (64) into the end chamber (42), as shown in Figure 6.

[00151] In one variant, the restraining element (98) comprises a ring defined in the end chamber (42) or a protruding part of the cannula (64) projecting towards the end chamber (42) inserted into a circular groove defined in the end chamber (42).

[00152] This constraint element (98) can also be used in the embodiment shown in Figure 2.

[00153] A fifth embodiment of the invention is shown. Petition 870260014487, dated 02 / 13 / 2026, pp. 34 / 45 24 / 24 in Figure 7. This embodiment is described by differences in relation to the embodiment in Figure 5.

[00154] The front sealing assembly (54) comprises two annular projections (66) arranged along the longitudinal direction (X-X'). Preferably, the two projections (66) have the same geometric characteristics.

[00155] One of the protrusions (66) extends radially into the intermediate region (49) of the end chamber (42).

[00156] In addition, the front seal assembly (54) may comprise a test hole (76) set in the end chamber (42) disposed between the two protrusions (66). The test hole allows checking the seal of an internal space bounded by the inner surface (48) of the end chamber (42) and an outer surface of the inner sheath (18), between the annular protrusions (66).

Claims

Claims 1. END FITTING (14) OF A FLEXIBLE TUBE (10) FOR TRANSPORTING A FLUID, comprising: - an end chamber (42) and an outer cover (44) fixed around the end chamber (42) and delimiting a receiving chamber (46), - at least one front region (36) of an inner polymeric sheath (18) defining a central passage (16) for transporting the fluid, the central passage (16) extending in a longitudinal direction (X-X'), - at least end sections (40) of at least one layer of tensile armor (24, 25) arranged around the inner polymeric sheath (18), the end sections (40) being arranged in the receiving chamber (46), - a front seal assembly (54) arranged around the front region (36) of the inner polymeric sheath (18),the end fitting (14) comprising the front seal assembly (54) which includes a cannula (64) supporting at least part of the front region (36) of the inner polymer sheath (18) and at least one annular protrusion (66) disposed on an inner surface (48) of the end chamber (42) projecting towards the central passage (16), at least part of the front region (36) of the inner polymer sheath (18) being circumferentially tightened between at least one protrusion (66) and the cannula (64), characterized in that at least one protrusion (66) is integral with the end chamber (42).

2. END FITTING (14), according to claim 1, characterized in that at least one protrusion (66) is an annular ring. Petition 870260014487, dated 13 / 02 / 2026, page 36 / 45 2 / 4 3. END FITTING (14), according to any one of claims 1 to 2, characterized in that at least a part of the front region (36) of the inner polymeric sheath (18) is plastically deformed by the protrusion (66).

4. END FITTING (14), according to any one of claims 1 to 3, characterized in that the front sealing assembly (54) comprises two annular projections (66) separated along the longitudinal direction (X-X').

5. END FITTING (14), according to claim 4, characterized by further comprising a test hole (76) defined in the end chamber (42) to check the sealing of an internal space delimited by the inner surface (48) of the end chamber (42) and an outer surface of the inner polymeric sheath (18), between the annular protrusions (66).

6. END FITTING (14), according to any one of claims 1 to 5, characterized in that the front seal assembly (54) comprises a retaining element (96) for holding the cannula (64) fixed to the end chamber (42).

7. END FITTING (14), according to any one of claims 1 to 6, characterized in that the inner polymeric sheath (18) is a polymeric pressure sheath (20) intended to hermetically confine the fluid carried by the central passage (16).

8. END FITTING (14), according to claim 7, characterized in that the polymeric pressure sleeve (20) has a thickness between 5 mm and 20 mm.

9. END FITTING (14), according to any one of claims 1 to 6, characterized by further comprising a front region (62) of a pressure sleeve (20), the inner polymeric sleeve (18) being a protective polymeric sleeve (34) intended to protect the pressure sleeve (20), the pressure sleeve (20) being disposed around the protective polymeric sleeve (34).

10. END FITTING (14), according to claim 9, characterized by further comprising an intermediate sealing assembly (56) disposed around the front region (62) of the pressure sleeve (20).

11. FLEXIBLE TUBE (10) FOR TRANSPORTING A FLUID, characterized by comprising: - at least one inner polymeric sheath (18) defining a central passage (16) for transporting the fluid, the central passage (16) extending in a longitudinal direction (X-X'), - at least one tensile armor layer (24, 25) arranged around the inner polymeric sheath (18), and - an end fitting (14), as defined in any one of claims 1 to 10.

12. FLEXIBLE TUBE (10), according to claim 11, characterized by comprising an end fitting (14), as defined in any one of claims 1 to 8, and a pressure sheath (20) intended to hermetically confine the fluid carried by the central passage (16), the inner polymeric sheath (18) being formed by the pressure sheath (20).

13. FLEXIBLE TUBE (10), according to claim 11, characterized by comprising an end fitting (14), as defined in any of claims 9 to 10, a pressure sheath (20) and a protective polymer sheath (34) intended to protect the pressure sheath (20) and intended to hermetically confine the fluid transported by the central passage (16), the pressure sheath (20) being disposed around the protective polymer sheath (34), the inner sheath (18) being formed by the protective polymer sheath (34).

14. METHOD FOR ASSEMBLING AN END FITTING (14), as defined in any of claims 1 to 10, characterized in that the method comprises the following steps: - providing a flexible tube (10), - providing an end chamber (42) comprising at least one annular protrusion (66) disposed on the inner surface (48) of the end chamber (42), at least one protrusion (66) projecting towards the central passage (16), - fixing the end chamber (42) over at least a part of the front region (36) of the inner sheath (18), - providing a cannula (64), - inserting the cannula (64) to support at least a part of the front region (36) of the inner sheath (18) to circumferentially tighten at least a part of the front region (36) of the inner sheath (18) between at least one annular protrusion (66) and the cannula (64).

15. METHOD FOR REPLACING AN INNER SHEATH (18) IN A FLEXIBLE TUBE (10), as defined in claim 13, characterized in that the method comprises the following steps: - removing the cannula (64), - extracting the inner sheath (18) from the flexible tube (10) from one end of the end fitting (14), - inserting a new inner sheath (18) through the end of the end fitting (14), - inserting a new cannula (64) into the inner sheath (18) to circumferentially tighten at least part of the front region (36) of the inner sheath (18) being between at least one protrusion (66) of the front seal assembly (54) and the cannula (64).

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