AU2015216937B2

AU2015216937B2 - Flexible pipe for transporting a fluid equipped with a lazy-S-shaped insert and associated method for manufacture

Info

Publication number: AU2015216937B2
Application number: AU2015216937A
Authority: AU
Inventors: Patrice Jung; Philippe Secher
Original assignee: Technip France SAS
Current assignee: Technip Energies France SAS
Priority date: 2014-02-13
Filing date: 2015-02-13
Publication date: 2019-07-25
Anticipated expiration: 2035-02-13
Also published as: WO2015121424A8; WO2015121424A1; AP2016009379A0; FR3017439B1; FR3017439A1; MY179971A; AU2015216937A8; EP3105484B1; EP3105484A1; AU2015216937A1; CN106104127A; CN106104127B; DK3105484T3; BR112016018742A2; BR112016018742B1

Abstract

This pipe comprises a rough-bore internal carcass (26), arranged inside an internal sheath, the internal carcass (26) comprising a first folded tape (31) delimiting a helicoidal gap (40) opening toward the central axis and a helicoidal insert closing off this helicoidal gap (40) toward the inside. The helicoidal insert (28) has in cross section the shape of a lazy S, the section being taken on an axial midplane, the lazy-S-shape cross section comprising an axial exterior region (42), a radial intermediate region (44) and an axial interior region (46) projecting from the radial intermediate region (44) axially in the opposite direction to and radially some distance away from the axial exterior region (42), the axial interior region (46) at least partially closing off the helicoidal gap (40).

Description

Flexible pipe for transporting a fluid equipped with a lazy-S-shaped insert and associated method for manufacture

The present invention relates to a flexible pipe for transporting a fluid, including:

an internal polymeric sheath delimiting a passage for circulation of fluid with a central axis;

at least one layer of armors positioned on the outside of the internal sheath;

an internal carcass, positioned in the internal sheath, the internal carcass comprising a first bent tape delimiting a helicoidal gap opening towards the central axis;

a helicoidal insert obturating the helicoidal gap towards the inside.

The pipe is preferably a flexible pipe of the unbonded type, intended for transport of hydrocarbons through a stretch of water, such as an ocean, a sea, a lake or a river.

Such a flexible pipe is for example manufactured according to the standardized documents API 17J (Specification for Unbonded Flexible Pipe) and API RP 17B (Recommended Practice for Flexible Pipe) established by the American Petroleum Institute.

The pipe is generally formed with an assembly of concentric and superposed layers. It is considered as « unbonded » in the sense of the present invention from the moment that at least one of the layers of the pipe is able to move longitudinally with respect to the adjacent layers during flexure of the pipe. In particular, an unbonded pipe is a pipe without any bonding materials connecting layers forming the pipe.

The pipe is generally positioned through a stretch of water, between a bottom assembly, intended to collect the exploited fluid at the bottom of the stretch of water and a floating or fixed surface assembly, intended to collect and distribute the fluid. The surface assembly may be a semi-submersible platform, an FPSO or another floating assembly.

In certain cases, the flexible pipe comprises an internal carcass positioned in the pressure sheath, in order to avoid crushing of the pressure sheath, under the effect of the external pressure, for example upon depressurization of the internal passage for circulation of fluid delimited by the pressure sheath.

The internal carcass is generally formed with a profiled metal tape, wound as a spiral. The turns of the tape are stapled to each other. The turns delimit between them a helicoidal gap radially opening inwards into the central passage for circulation of the fluid.

The internal surface of the carcass therefore axially exhibits a succession of recesses and bumps. The pipe is then generally described by the term of« rough bore »..

In certain cases, the circulation of the fluid along the carcass is perturbed by the raised/recessed portions defined on the carcass by the helicoidal gap.

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This perturbation of flow is sometimes considered as the origin of vibratory phenomena within the flexible pipe, or even, when a resonance is attained, of pulses induced by the circulation of fluid (« flow induced pulsations » or « singing »).

In order to overcome this problem, it is known how to manufacture flexible pipes without any internal carcass and therefore having a smooth surface (« smooth bore »).

Another solution to this problem is described in WO 2014/000816. In this document, the flexible pipe comprises a carcass in which a helicoidal insert with a Tshaped section is jammed in the gap present between the different turns of the carcass. The insert obturates the gap towards the inside.

The T-shaped profile is manufactured from two planar sheets, for example by welding between the sheets.

The manufacture of such an insert, and its positioning in the carcass is therefore very difficult to apply industrially.

In particular, assembling by welding of two sheets requires the application of significant pieces of equipment online, such as unwinders, an assembler, a laser welding station, etc.

The T-shaped profile described in this document is therefore not simple to produce, and may lead to industrial problems and to a high price cost for the pipe.

An example of the invention seeks to provide a pipe in which the risk of vibrations, or even of pulsations is limited, and which is nevertheless simple and economical to manufacture on an industrial scale. Alternatively or additionally, an example of the invention seeks to at least provide the public with a useful choice.

For this purpose, the present invention provides a pipe of the aforementioned type, wherein the helicoidal insert is partly positioned in the helicoidal gap and obturates the helicoidal gap towards the central axis, the helicoidal insert having a lazy-S-shaped section, taken in a axial midplane, the lazy-S-shaped section including an axial outer region, a radial intermediate region and an axial inner region protruding from the radial intermediate region axially opposite to and radially away from the axial outer region, the axial inner region obturating at least partly the helicoidal gap; and wherein the inner assembly formed by the carcass and by the insert is permeable to the passing of the fluid from the inside of the carcass to the outside of the carcass.

The pipe according to the invention may comprise one or several of the following features, taken individually or according to any technically possible combination:

- the radial intermediate region is tilted with respect to an axis perpendicular to the central axis, axially away from the axial inner region;

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- the radial intermediate region comprises, in section, a linear intermediate segment, a curved connecting outer segment, the axial outer region protruding from the connecting outer segment, and a curved connecting inner segment, with curvature opposite to that of the connecting outer segment, the axial inner region protruding from the connecting inner segment;

- the axial inner region has an axial width greater than that of the axial outer region;

- the axial inner region has a rounded free edge and/or a thinned region in the vicinity of the free edge;

- the axial inner region extends substantially parallel to the axial outer region;

- the helicoidal insert includes a plurality of turns, each turn of the helicoidal insert including a section, taken in an axial midplane, including an axial inner region, a radial intermediate region and an axial outer region protruding from the radial intermediate region axially opposite and radially away from the axial inner region, the axial inner region of a first turn being interiorly applied on the axial inner region of a second turn adjacent to the first turn;

- the carcass includes a plurality of stapled turns, each turn of the carcass having an inner portion, an intermediate portion, the inner portion having the shape of a bent U towards the intermediate portion and an outer portion, the outer portion having the shape of a U bent back towards the intermediate portion, the axial outer region of each turn of the helicoidal insert being clamped between the inner portion of a first turn of the carcass and the outer portion of a second turn of the carcass engaged into the first turn of the carcass;

- the radial intermediate region is applied against the intermediate portion, the 25 inner region advantageously protruding axially beyond the inner portion; and

- the helicoidal insert delimits at least one duct for passage of fluid connecting the gap to the circulation passage, the duct being advantageously delimited by an imprint and/or a recess/raised portion present in the outer region and/or in the inner region.

The present invention also provides a method for manufacturing a flexible pipe, 30 comprising the following steps:

- forming an internal carcass, the internal carcass comprising a first bent tape delimiting a helicoidal gap opening towards the central axis;

- producing an internal polymeric sheath delimiting a passage for circulation of fluid of a central axis, the internal carcass being positioned in the internal sheath;

- positioning at least one external layer of armors on the outside of the internal sheath;

2015216937 24 Jun 2019 the method including the setting into place of a helicoidal insert in the helicoidal gap, wherein the helicoidal insert is partly positioned in the helicoidal gap and obturates the helicoidal gap towards the central axis, the helicoidal insert having a lazy-S-shaped section, taken in a axial midplane, the lazy-S-shaped section including an axial outer region, a radial intermediate region and an axial inner region protruding from the radial intermediate region axially opposite to and radially away from the axial outer region, the axial inner region obturating at least partly the helicoidal gap; and wherein the inner assembly formed by the carcass and by the insert is permeable to the passing of the fluid from the inside of the carcass to the outside of the carcass.

The method according to the invention may comprise one or several of the following features, taken individually or according to any technically possible combination:

- it includes the passage of a second tape in an insert profiler in order to form an insert profile with a lazy-S-shaped section, the method including the passage of the first tape into a carcass profiler in order to form a carcass profile and the winding of the carcass profile and of the insert profile on the mandrel;

- the insert profiler and the carcass profiler are positioned on a same side of the mandrel or on either side of the mandrel;

- it includes, downstream from the insert profiler and from the carcass profiler, and upstream from the mandrel, a step for applying the insert profile against the carcass profile in order to form a combined profile wound on the mandrel;

- the combined profile is pushed on the mandrel after the applying step.

The invention will be better understood, upon reading the description which follows, only given as an example, and made with reference to the appended drawings, wherein:

- Fig. 1 is a partly cutaway perspective view of a central segment of a first flexible pipe according to an embodiment of the invention;

- Fig. 2 is a partial sectional view along a axial midplane, of a detail of the pipe of Fig. 1 illustrating the carcass and the insert positioned in the gap of the carcass;

- Fig. 3 is a view of a detail of Fig. 2, illustrating a lazy-S-shaped section of the insert;

- Figs. 4 and 5 illustrate two alternative conformations of the side edges of the profile of the insert;

- Fig. 6 is a schematic view at the end of a station for manufacturing and laying the carcass and the insert;

- Fig. 7 is a schematic partial sectional view along the axial plane VII of Fig. 5;

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- Fig. 8 is a view illustrating the operations carried out by the insert profiler for shaping the insert;

- Fig. 9 illustrates a system for inserting the insert profile into the carcass profile, in the manufacturing station of Fig. 5;

-Figs. 10 and 11 illustrate alternative inserts positioned in pipes according to embodiments of the invention;

-Figs. 12 and 13 are views similar to Fig. 5 illustrating alternative stations for manufacturing and laying the carcass and the insert;

- Fig. 14 illustrates another insert alternative.

In all the following, the terms of « outer» and « inner» are generally understood radially with respect to an axis A-A’ of the pipe, the term of « outer» being understood as relatively further away radially from the A-A’ and the term of « inner» extending as relatively and radially closer to the A-A’ axis of the pipe.

A first flexible pipe 10 according to an embodiment of the invention is partly illustrated by Fig. 1.

The flexible pipe 10 includes a central segment 12. It includes, at each of the axial ends of the central segments 12, an end-piece (not visible).

With reference to Fig. 1, the pipe 10 delimits a central passage 16 for circulation of a fluid, advantageously a petroleum fluid. The central passage 16 extends along an axis A-A’, between the upstream end and the downstream end of the pipe 10.

The flexible pipe 10 is intended to be positioned through a stretch of water (not shown) in an installation for exploiting fluid, notably hydrocarbons.

The stretch of water is for example, a sea, a lake or an ocean. The depth of the stretch of water at right angles to the installation for exploiting fluid is for example comprised between 500 m and 3,000 m.

The installation for exploiting a fluid includes a surface assembly notably floating, and a bottom assembly (not shown) which are generally connected together through the flexible pipe 10.

The flexible pipe 10 is preferably an « unbonded » pipe.

At least two adjacent layers of the flexible pipe 10 are free to move longitudinally with respect to each other during flexure of the pipe.

Advantageously, all the layers of the flexible pipe are free to move relatively to each other. Such a pipe is for example described in the standardized documents published by the American Petroleum Institute (API), API 17J, and API RP17B.

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As illustrated by Fig. 1, the pipe 10 delimits a plurality of concentric layers around the axis A-A’, which continuously extends along the central segment 12 as far as the endpieces located at the ends of the pipe.

According to embodiments of the invention, the pipe 10 includes at least one first tubular sheath 20 based on a polymeric material advantageously making up a pressure sheath.

The pipe 10 further includes at least one layer of tensile armors 24, 25 positioned exteriorly with respect to the first sheath 20 forming a pressure sheath.

The pipe 10 further includes an internal carcass 26 positioned inside the pressure sheath 20, optionally a pressure vault 27 inserted between the pressure sheath 20 and the layer(s) of tensile armors 24, 25, and an external sheath 30, intended for protecting the pipe 10.

According to embodiments of the invention, the pipe 10 further includes an insert 28 having a lazy-S-shaped cross-section, the insert 28 being positioned so as to be interiorly supported on the internal carcass 26.

In a known way, the pressure sheath 20 is intended to sealably confine the fluid transported in the passage 16. It is formed in a 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).

The thickness of the pressure sheath 20 is for example comprised between 5 mm and 20 mm.

As illustrated by Fig. 2, the carcass 26 is formed here with a first helicoidally wound profiled metal tape 31. The successive turns of the tape 31 are stapled with each other.

The main function of the carcass 26 is to absorb the squeezing radial forces.

The carcass 26 is positioned inside the pressure sheath 20. It is able to come into contact with the fluid circulating in the pressure sheath 20.

The helicoidal winding of the first profiled tape 31 forming the carcass 26 is with a short pitch, i.e. it has a helix angle with an absolute value close to 90°, typically comprised between 75° and 90°.

The first tape 31 has two edges longitudinally bent back on a central region. It defines a plurality of stapled turns with a closed and flattened S-shaped section, as illustrated by Fig. 2. The first tape 31 has a substantially constant thickness e1.

The closed S-shaped section of each turn of the carcass 26 successively comprises, parallel to the axis A-A’ from right to left in Fig. 2, an inner portion 32 with the general shape of U, a tilted intermediate portion 34 and an outer portion 36 in the general

2015216937 24 Jun 2019 shape of a U having, in vicinity to its free end, a supporting wave 38, commonly referred to with the term of « nipple ».

The inner portion 32 of each turn of the first tape 31 is bent back towards the intermediate portion 34 away from the central axis A-A’, exteriorly with respect to the tilted portion 34. It defines a U-section extending parallel to the A-A’ axis and opening facing the tilted portion 34.

The outer portion 36 of an adjacent turn is partly engaged into the inner portion 32, the supporting wave 38 being inserted between the branches of the U.

The inner portion 32 defines an inner surface 39 located on a cylindrical envelope of axis A-A’.

The outer portion 36 also defines a U section extending parallel to the A-A’ axis and opening facing the tilted portion 34.

The outer portion 36 of each turn is bent back towards the intermediate portion 34, towards the central axis A-A’, interiorly with respect to the tilted portion 34. The outer portion 36 and the supporting wave 38 of the section are received into the inner portion 32 of an adjacent section, and partly covering outwards the inner portion 32 of the adjacent section.

For each turn, the intermediate portion 34, the outer portion 36 and the inner portion 32 of an adjacent section delimit an inner gap 40, partly or completely defining the axial play of the carcass 26.

The gap 40 radially opens towards the central axis A-A’. For each turn, it opens interiorly towards the axis A-A’ between the inner surfaces 39 of the inner portions 32 of two adjacent turns.

Exteriorly, it is obturated by the outer portion 36 and laterally by the intermediate portion 34 of a turn and by the inner portion 32 of an adjacent turn.

The gap 40 thus continuously extends as a helix of axis A-A’, according to a pitch P1 along the carcass 26.

Each turn of the carcass 26 has a width advantageously comprised between 25 mm and 100 mm.

The carcass 26 has, between each pair of stapled turns, a first axial play defined by the relative sliding axial travel of the outer portion 36 of a turn in the inner portion 32 of an adjacent turn into which it is engaged. According to the invention, the insert 28 is partly positioned in the gap 40 and obturates the gap 40 towards the axis A-A’.

The insert 28 thus advantageously has a helicoidal shape of axis A-A’, with a pitch P1 similar to the pitch of the gap 40.

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As illustrated by Fig. 3, the insert 28 has a section, taken in a axial midplane, of a lazy-S-shape.

It includes an axial outer region 42, a radial intermediate region 44 and an axial inner region 46 protruding from the intermediate region 44, axially opposite to and radially away from the axial outer region 42,

The axial inner region 46 obturates at least partly the gap 40. Advantageously, the axial inner region 46 completely obturates the gap 40.

According to embodiments of the invention, the insert 28 is made in a single piece by bending a second tape 48.

The second tape 48 is preferably metal. It advantageously has a constant thickness e2. The thickness e2 of the second tape 48 is preferably less than the thickness e1 of the first tape 31. The thickness e2 of the second tape 48 is advantageously comprised between one-third and two-thirds of the thickness e1 of the first tape 31.

The thickness e2 is for example comprised between 0.5 mm and 2 mm, notably between 0.8 mm and 1.5 mm.

Such a thickness guarantees sufficient stiffness, while limiting the risk of disorganization upon introducing a probe into the central passage (“pigging”).

In the example illustrated in Fig. 2 and Fig. 3, the outer region 42 extends over a cylindrical envelope of central axis A-A'.

The outer region 42 is clamped between the outer branch of the U of the outer portion 36 of a turn of the carcass 26 and the outer branch of the U of the inner portion 32 of an adjacent turn of the carcass 26. It is applied against the inner surface of the outer portion 36.

The outer region 42 has an advantageously rounded free edge.

As illustrated by Fig. 3, the intermediate region 44 comprises a curved connecting outer segment 50 with the outer region 42, an intermediate segment 52 with a linear section, and a curved inner segment 54 connected with the inner region 46.

The outer segment 50 has a convexity curvature directed outwards. The radius of curvature of the outer segment 50 is advantageously greater than the thickness e2 of the second tape 48.

The intermediate segment 52 extended in a tilted way with respect to an axis perpendicular to the central axis A-A’ while being axially located away from the outer segment 42 and from the inner segment 46.

The inner segment 54 has a curvature of convexity which is directed inwards, opposite to the convexity of the curvature of the outer segment 50. It has a radius of curvature greater than the radius of curvature of the outer segment 50.

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The intermediate region 44 is applied on an inner surface of the intermediate portion 34.

It is positioned in the gap 40 between the intermediate portion 34 and the outer portion 36 of a turn of the carcass 26, and the inner portion 32 of an adjacent turn of the carcass 26.

The outer region 42 axially protrudes from the outer segment 50 of the intermediate region 44.

The inner region 46 also extends axially along the axis A-A’, over a cylindrical envelope of A-A’ or with an angle of less than 10° with respect to this envelope.

Preferably, the inner region 46 is elastically urged towards a tilted position with respect to the cylindrical envelope of axis A-A’, directed outwards, as illustrated in thin lines in Fig. 3, when it is positioned on a cylindrical envelope of axis A-A’.

The width L1 of the inner region 46, taken along the axis A-A’ is greater than the width L2 of the outer region 42, taken along the axis A-A’.

The inner region 46 axially extends opposite to the outer region 42 with respect to the intermediate region 44, and radially away from the latter.

It protrudes from the inner segment 54 of the intermediate region 44.

With reference to Fig. 3, the inner region 46 of each turn of the insert 28 includes a first axial segment 56 applied on the inner surface 39 of the inner portion 32 of a turn of the carcass 26, an axial intermediate segment 58 obturating inwards the gap 40 delimited by the inner portion 32, and a second axial segment 60 applied on an inner surface of the inner region 46 of an adjacent turn of the insert 28, at the first axial segment 56 of this inner region 46.

The inner region 46 of each turn of the insert 28 is advantageously maintained applied against the inner surface of the inner region 46 of a turn of the insert 28, by elastically urging the inner region 46 outwards.

Thus, the successive turns of the insert 28 overlap each other by their inner regions 46, in order to obturate the gap 40 inwards.

The overlapping width of each inner region 46, when the carcass 26 occupies a non-deformed linear configuration is greater than the axial play of the carcass 26.

In the embodiment illustrated in Fig. 4, the inner region 46 has a rounded free edge 62, and constant thickness in the vicinity of the rounded free edge 62.

In the alternative illustrated in Fig. 5, the inner region 46 has a rounded free edge 62, and a thickness which decreases towards the free edge 62 in the vicinity of the latter.

This arrangement improves flow of the fluid circulating in the passage 16.

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With reference to Fig. 1, the pressure vault 27 is intended to absorb the forces related to the pressure prevailing inside the pressure sheath 20. For example it is formed with a helicoidally wound metal profiled wire around the sheath 20. The profiled wire generally has a complex geometry, notably Z-shaped, T-shaped, U-shaped, K-shaped, Xshaped or l-shaped.

The pressure vault 27 is helicoidally wound with a short pitch around the pressure sheath 20, i.e. with a helix angle of an absolute value close to 90°, typically comprised between 75° and 90°.

The flexible pipe 10 according to embodiments of the invention comprises at least one layer of armors 24, 25 formed with a helicoidal winding of at least one elongated armor element 63.

In the example illustrated in Fig. 1, the flexible pipe 10 includes a plurality of layers of armors 24, 25, notably an inner layer of armors 24, applied on the pressure vault 27 and an outer layer of armors 25 around which is positioned the outer sheath 30.

Each layer of armors 24, 25 includes longitudinal armor elements 63 wound with a long pitch around the axis A-A’ of the pipe.

By “wound with a long pitch”, is meant that the absolute value of the helix angle is less than 60°, and is typically comprised between 25° and 55°.

The armor elements 63 of a first layer 24 are generally wound according to an opposite angle with respect to the armor elements 63 of a second layer 25. Thus, if the winding angle of the armor elements 63 of the first layer 24 is equal to + α, a being comprised between 25° and 55°, the winding angle of the armor elements 63 of the second layer of armors 25 positioned in contact with the first layer of armors 24 is for example equal to - a°.

The armor elements 63 are for example formed with metal wires, notably steel wires, or with strips in composite material, for example strips reinforced with carbon fibers.

The external sheath 30 is intended to prevent permeation of fluid from the outside of the flexible pipe 10 towards the inside. It is advantageously made in a polymeric material, notably based on a polyolefin, such as polyethylene, or on the basis of a polyamide, such as PA11 or PA12.

The thickness of the external sheath 30 is for example comprised between 5 mm and 15 mm.

The carcass 26 and the insert 28 are made and are set into place simultaneously in a manufacturing and laying station 70, schematically illustrated by Figs. 6 and 7.

As illustrated by these figures, the station 70 includes a rotary mandrel 72 around an axis A-A’, intended to guide the winding of the carcass 26 and of the insert 28.

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The station 70 includes a rotary support 73 around the axis A-A’ and with respect to the mandrel 72, a first unwinder 74 (schematically illustrated) receiving the first tape 31, and a carcass profiler 76 positioned downstream from the first unwinder 74 between the first unwinder 74 and the mandrel 72.

The station 70 further includes a second unwinder 78 (schematically illustrated) receiving the second tape 48, an insert profiler 80, positioned downstream from the second unwinder 78 between the second unwinder 78 and the mandrel 72.

Advantageously, the station 70 includes a system 81 for joining up together the tapes 31,48 at their outlet from the profilers 76, 80.

The station 70 further includes members 82 for radial applying of the carcass 26 and of the insert 28 against the mandrel 72, and advantageously, return members 83 for guiding the first tape 31 and the second tape 48 from each unwinder 74, 78 to a respective profiler 76, 80.

The rotary mandrel 72 axially protrudes from the support 73 along a winding axis A-A’.

With reference to Fig. 7, the mandrel 72 includes a supporting body 84, on which a first carcass profile 85, obtained from the first deformed tape 31 in the carcass profiler 76 and a second insert profile 87, obtained from the second deformed tape 48 in the insert profiler 80 are applied.

In this example, the rotary mandrel 72 further includes an assembly 86 for lubricating the outer surface 88 of the body 84.

The supporting body 84 for example has a suitable surface coating for reducing its friction coefficient. The friction coefficient of the outer surface 88 with respect to the insert 28 is for example less than 0.1 in the presence of lubrication.

The supporting body 84 has an upstream region 92 substantially cylindrical for assembling the insert 28 and the carcass 26 from profiles 85, 87 and a downstream frustoconical region 94 for disengaging the insert 28 and the carcass 26.

The lubrication assembly 86 includes a central channel 96 for injecting lubricant, made in the supporting body 84. The channel 96 opens through transverse apertures 98 into the upstream region 92.

The rotary mandrel 72 is able to be driven into rotation around the axis A-A’ with a velocity and a direction rotation different from those of the support 73.

Advantageously, the mandrel 72 is driven into rotation in a direction opposite to that of the support 73, and with a velocity of less than 10 % of the one of the support 73.

This allows rapid disengagement of the insert 28 formed bearing upon the surface 88, and avoids seizure or jamming problems of the carcass 26 on the mandrel 72.

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The rotation of the rotary mandrel 72 tends to locally increase the internal diameter of the carcass 26 for promoting its discharge.

The support 73 for example includes a plate driven into rotation around the axis AA’ in the winding direction of the insert 28 and of the carcass 26.

The support 73 bears unwinders 74, 78, and profilers 76, 80. In this example, the profilers 76, 80 are positioned diametrically on the same side relatively to a axial midplane passing through the axis A-A’.

The profilers 76, 80 are for example located on each other.

Each profiler 76, 80 includes a plurality of pairs of rollers 100 for deforming the tape 31, 48, which define a respective B-B’, C-C’ axis for respectively supplying the carcass 26 and the insert 28 on the mandrel 72.

The profilers 76, 80 are translationally movable on the support 73 in a plane perpendicular to the winding axis A-A’. The insert profiler 80 is able to be pivoted around its axis C-C’ for adjusting the introduction angle of the insert profile 87 into the joining-up system 81.

With reference to Fig. 9, the joining-up system 81 includes two guide rollers 102, 104 placed facing each other and advantageously, a profile guide 106, visible in Fig. 6, interposed between the insert profiler 80 and the guide rollers 102,104. The profile guide 10 includes means for guiding the insert 28 between the downstream side of the insert profiler 80 on the one hand and both guide rollers 102,104 on the other hand.

These guiding means fit the geometry of the insert 28 and include a set of guiding rollers and/or one or several guiding ramps having a low friction coefficient.

As visible in Fig. 9, the inner guiding roller 102 has a recessed/raised portion 108 delimiting an outer surface with a shape conjugate to the inner surface of the first insert profiler 87, facing the outer region 42, the intermediate region 44 and the inner region 46.

The outer guiding roller 104 has a mating recessed/raised portion 110 with a shape conjugate to that of the recessed/raised portion 108, and mating that of the outer surface of the carcass profile 85 on the outer portion 36, on the intermediate portion 34, and on the inner branch of the inner portion 32.

The outer guiding roller 104 delimits a housing 111 for accommodating the outer branch of the U of the inner portion 32.

The rollers 102, 104 delimit between the recessed/raised portions 108, 110, an intermediate space with a thickness substantially corresponding to the sum of the thicknesses of the first tape 31 and of the second tape 48.

As this will be seen below, the guiding rollers 102, 104 are able to apply the second profile 87 onto the first profile 85 in order to form a combined profile 112, visible in

2015216937 24 Jun 2019

Figs. 6 and 7, and to urge the combined profile 112 towards the mandrel 72, by means of an « urged wire » motorization.

The radial applying members 82 are positioned radially around the surface 88. They for example include knurls able to be radially applied on the outside of the insert 28 and of the carcass 26 in order to finalize the arrangement of the insert 28 in the helicoidal gap 40, and the stapling of the carcass 26, as illustrated in Fig. 7.

In one alternative, in order to facilitate disengagement of the insert 28 and of the carcass 26 away form the mandrel 72, the radial applying members 82 located on the mandrel 72 are able to exclusively partly able to close the carcass 26. A specific mandrel (not shown), associated with additional applying members is then provided downstream from the mandrel 72.

A method for manufacturing the flexible pipe 10 will now be described. Initially, the tapes 31,48 are loaded on the unwinders 74, 78.

Next, the tapes 31, 48 are unwound in order to be respectively introduced into the profilers 76, 80. Simultaneously, the support 73 is driven into rotation around the axis AA.

In the carcass profiler 76, the first tape 31 is successively deformed in order to produce the first profile 85 including the inner portion 32, the intermediate portion 34 and the outer portion 36, without totally closing the inner portion 32 and the outer portion 36, as illustrated by figs.7 and 9.

In particular, the inner branch of the U of the outer portion 36 remains partly opened, as well as the outer branch of the U of the inner portion 32.

In the insert profiler 80, as illustrated by Fig. 8, the second tape 48 is deformed and bent along intermediate axes E-E’, F-F’ located on either side of the central axis of the tape 48 in order to form the outer region 42, the intermediate region 44 and the inner region 46 (steps (a) to (c) in Fig. 8). The deformation is continued by curving connecting segments 50, 54 (steps (d) in Fig. 8).

A second profile 87 with a lazy-S-shaped section comprising an outer axial region 42, an axial inner region 46 opposite to the axial outer region 42 and an intermediate radial region 44 is then obtained, in order to form the insert 28.

The second profile 87 is then joined up with the first profile 85 in the joining-up system 81, while being guided towards the joining-up system 81 by the profile guide 106.

In the system 81, the first profile 85 is applied against the second profile 87 between the recessed/raised portions 108, 110.

The outer region 42 is applied against the outer branch of the U of the outer portion 36, the inner branch remaining positioned outside the rollers 102, 104.

2015216937 24 Jun 2019

The intermediate region 44 is applied against the intermediate portion 34.

The inner region 46 is applied against the inner branch of the U of the inner portion 32, the outer branch of the U of the inner portion 32 being introduced into the housing

111.

A combined profile 112 is thus obtained and is supplied with “urged wire” through the joining-up system 81, while being oriented tangentially with respect to the outer surface 88 of the mandrel 72.

The combined profile 112 is applied upon the outer surface 88 of the body 84 and is helicoidally wound, with the desired pitch for inserting into the gap 40, thus forming the insert 28 and the carcass 26.

Simultaneously, the partly open outer portion 36 of each turn of the first profile 85 is inserted into the inner portion 32 of an adjacent turn, the outer region 42 of the insert 28 being inserted between the outer portion 36 of the turn and the inner portion 32 of the adjacent turn.

Moreover, the inner region 46 of each turn of the second profile 87 is applied on the inner region 46 of an adjacent turn in order to obturate the gap 40 being formed.

The radial applying members 82 are then applied on the outside of the carcass 26 and of the insert 28 in order to close and staple the carcass 26, while ensuring internal adjustment of the insert 28 in the helicoidal gap 40.

The thereby formed turns of the carcass 26 and of the insert 28 are gradually disengaged towards the downstream side, while being detached from the mandrel 72 under the effect of the lubrication provided by the lubrication assembly 86, of the frustoconical shape of the downstream portion 94 of the body 84, and from the rotation differential between the support 73 and the mandrel 72 tending to inflate the carcass 26.

Once the carcass 26 is made, and the insert 28 is positioned in the carcass 26, the internal sheath 20 is formed around the carcass 26, for example by extrusion. The pressure vault 27 and the armor layers 24, 25 are then wound around the internal sheath 20.

The external sheath 30 is then advantageously made by extrusion, while being positioned outside the layers of armors 24, 25.

In one alternative, at least one duct 120 for letting through fluid connecting the gap 40 to the circulation passage 16 is made in the insert 28.

In the example illustrated in Figs. 10 and 11, at least one duct 120 is axially formed in the inner region 46 at least along the second axial segment 60.

In the inner region 46, the duct 120 extends axially from the gap 40 towards the free edge.

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The first end of this duct 120, located on the side of the free edge of the inner region 46 of the insert 28, opens directly into the circulation passage 16 of the pipe 10. The other end of the duct 120 is located in the axial intermediate segment 58 so that it directly opens into the helicoidal gap 40 of the carcass 26. The duct 120 therefore allows circulation of fluids between the gap 40 on the one hand and the circulation passage 16 on the other hand.

Thus, by means of the duct 120, the inner assembly formed by the carcass 26 and the insert 28 is permeable to the passing of fluid from the inside of the carcass 26 towards the circulation passage 16 of the pipe 10. This characteristic avoids damaging the insert 28 when the pipe 10 conveys a fluid under high pressure, notably a gas and when it has to be rapidly depressurized or pressurized.

Indeed, a significant pressure difference between the internal and external faces of the insert 28 may irreversibly damage the insert 28. It is therefore advantageous to balance the pressures on either side of the insert 28 by facilitating the flow of fluid between the gap 40 and the passage 16. The duct 120 reduces the pressure drops of this flow, which limits the pressure difference between the internal and external faces of the insert 28, and this even when the pipe is depressurized or pressurized rapidly.

In the example illustrated in Fig. 10, the duct 120 is delimited by an axial imprint 121 made in the outer surface 122 of the inner region 46 positioned and bearing upon the inner surface 39 of the inner portion 32.

The depth ofthe imprint 121 is advantageously comprised between 10% and 30% of the thickness e2 of the second tape 48. The width of the imprint 121, measured perpendicularly to the longitudinal axis of the channel 120, is advantageously comprised between once and three times the thickness e2 of the second tape 48.

In order to facilitate flow of the fluids on either side of the insert 28 over the whole length of the pipe 10, it is advantageous to have a large number of imprints 121 all along the insert 28. Advantageously, the insert includes at least one imprint 121 per linear meter of insert 28, preferentially at least one imprint 121 per linear decimeter of insert 28. For very severe applications for transporting gas under high pressure, the insert 28 may include as much as one imprint 121 per linear centimeter of insert 28.

These imprints are advantageously manufactured in the same time as the insert 28 by the manufacturing station 70.

For this purpose, the insert profiler 80 is equipped with a plurality of pairs of rollers 100 at least one of which, advantageously the one located the most downstream, comprises a roller provided with raised/recessed bosses intended to locally crush the second tape 48 for generating the imprints 121. The distance separating two neighboring

2015216937 24 Jun 2019 imprints 121 along the insert 28 depends on the diameter of this roller, as well as on the number and on the angular position of the bosses with which it is provided.

In the alternative illustrated in Fig. 11, the duct 120 is limited by a raised/recessed portion with the shape of a wave 123 positioned and bearing upon the inner surface 39, in order to move at least partly the outer surface 122 away from the inner surface 39.

The depth of the imprint 121 and/or of the raised/recessed portion with the shape of a wave 123 is advantageously comprised between 0.1 mm and 0.3 mm. The number of imprints 121 and/or of raised/recessed portions with a wave shape 123 is comprised for example between 3 and 9 per turn.

According to alternatives not illustrated in the figures, the outer region 42 of the insert 28 is also itself equipped with one or several ducts similar to the duct 120, this or these ducts axially extending from the free edge of the outer region 42 and towards the gap 40. This or these additional ducts are made in the inner surface of the outer region 42, so that they directly open into the gap 40.

Thus, the inner assembly formed by the carcass 26 and the insert 28 is permeable to the passing of fluid from the inside of the carcass 26 to the outside of the carcass 26.

In the alternative illustrated in Fig. 14, the duct 120 consists in a hole 124 crossing right through the second tape 48 at the axial intermediate segment 58 so that this hole 124 directly opens into a helicoidal gap 40 of the carcass 26.

Fig.12 illustrates an alternative manufacturing and laying station 70. In this example, the profilers 76, 80 are positioned diametrically opposite to each other on either side of a axial midplane passing through the axis A-A’.

Fig. 13 illustrates another alternative manufacturing and laying station 70. In this example, the profilers 76, 80 are combined on a double profiler including two trains of superposed profiling rollers 100.

As indicated above, the permeable inner assembly formed by the carcass 26 and the insert 28 allows balancing of the pressures on either side of this assembly.

Such a configuration is therefore totally opposed to that of a totally leak-proof metal pipe as described in US 2002/195157 which aims at containing a fluid inside the pipe without any fluid leak.

While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the present invention should not be limited by any of the above described exemplary embodiments.

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The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge 5 in the field of endeavor to which this specification relates.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word comprise, and variations such as comprises and comprising, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers 10 or steps

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Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A flexible pipe for transporting a fluid, comprising:

5 an internal polymeric sheath delimiting a passage for circulation of fluid with a central axis;

at least one layer of armors positioned outside the internal sheath;

an internal carcass, able to come into contact with the fluid circulating in the internal sheath, the internal carcass being positioned in the internal sheath, the internal

10 carcass comprising a first bent tape delimiting a helicoidal gap opening towards the central axis;

a helicoidal insert obturating inwards the helicoidal gap;

wherein the helicoidal insert is partly positioned in the helicoidal gap and obturates the helicoidal gap towards the central axis,

15 the helicoidal insert having a lazy-S-shaped section taken in an axial midplane, the lazy-S-shaped section including an axial outer region, a radial intermediate region and an axial inner region protruding from the radial intermediate region axially opposite to and radially away from the axial outer region, the axial inner region obturating at least partly the helicoidal gap; and

20 wherein the inner assembly formed by the carcass and by the insert is permeable to the passing of the fluid from the inside of the carcass to the outside of the carcass.
2. The pipe according to claim 1, wherein the radial intermediate region is tilted relatively to an axis perpendicular to the central axis, axially away from the axial inner

25 region.
3. The pipe according to claim 1 or 2, wherein the radial intermediate region comprises, in section, a linear intermediate segment, a curved connecting outer segment, the axial outer region protruding from the connecting outer segment, and a curved

30 connecting inner segment, with curvature opposite to that of the connecting outer segment, the axial inner region protruding from the connecting inner segment.
4. The pipe according to any of the preceding claims, wherein the axial inner region has an axial width greater than that of the axial outer region.

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5. The pipe according to any of the preceding claims, wherein the axial inner region has a rounded free edge and/or a thinned region in the vicinity of the free edge.
6. The pipe according to any of the preceding claims, wherein the axial inner region extends substantially parallel to the axial outer region.
7. The pipe according to any of the preceding claims, wherein the helicoidal insert includes a plurality of turns, each turn of the helicoidal insert including a section, taken in an axial midplane, including an axial inner region, a radial intermediate region and an axial outer region protruding from the radial intermediate region axially opposite to and radially away from the axial inner region, the axial inner region of a first turn being interiorly applied on the axial inner region of a second turn adjacent to the first turn.
8. The pipe according to any of the preceding claims, wherein the carcass includes a plurality of stapled turns, each turn of the carcass having an inner portion, an intermediate portion, the inner portion having the shape of a U bent back towards the intermediate portion and an outer portion, the outer portion having the shape of a bent-back U towards the intermediate portion, the axial outer region of each turn of the helicoidal insert being clamped between the inner portion of a first turn of the carcass and the outer portion of a second turn of the carcass being engaged into the first turn of the carcass.
9. The pipe according to claim 8, wherein the radial intermediate region is applied against the intermediate portion.
10. The pipe according to any of the preceding claims, wherein the helicoidal insert delimits at least one duct for the passing of fluid connecting the gap to the circulation passage.
11. The pipe according to claim 9, wherein the inner region protrudes axially beyond the inner portion.
12. The pipe according to claim 10, wherein the duct is delimited by an imprint and/or a raised/recessed portion present in the outer region and/or in the inner region.

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13. The pipe according to any of the preceding claims, wherein the first tape delimits a plurality of stapled turns.
14. The pipe according to any of the preceding claims, wherein the radial intermediate region of the insert is positioned in the helicoidal gap.
15. A method for manufacturing a flexible pipe, comprising the following steps:

forming an internal carcass able to come into contact with the fluid circulating in the pressure sheath, the internal carcass comprising a first bent tape delimiting a helicoidal gap opening towards the central axis;

producing an internal polymeric sheath delimiting a passage for circulation of fluid with a central axis, the internal carcass being positioned in the internal sheath;

positioning at least one external armor layer outside the internal sheath;

the method including the setting into place of a helicoidal insert in the helicoidal gap, wherein the helicoidal insert is partly positioned in the helicoidal gap and obturates the helicoidal gap towards the central axis, the helicoidal insert having a lazy-S-shaped section, taken in an axial midplane, the lazy-S-shaped section including an axial outer region, a radial intermediate region and an axial inner region protruding from the radial intermediate region axially opposite to and radially away from the axial outer region, the axial inner region obturating at least partly the helicoidal gap; and wherein the inner assembly formed by the carcass and by the insert is permeable to the passing of the fluid from the inside of the carcass to the outside of the carcass.
16. The method according to claim 15, including the passage of a second tape in an insert profiler in order to form an insert profiler with a lazy-S-shaped section, the method including the passing of the first tape in a carcass profiler in order to form a carcass profiler and the winding of the carcass profiler and of the insert profiler on the mandrel.
17. The method according to claim 16, wherein the insert profiler and the carcass profiler are positioned on a same side of the mandrel or on either side of the mandrel.
18. The method according to any of claims 16 to 17, including, downstream from the insert profiler and from the carcass profiler, and upstream from the mandrel a step for

2015216937 24 Jun 2019 applying the insert profiler against the carcass profiler in order to form a combined profile wound on the mandrel.
19. The method according to claim 18, wherein the combined profile is urged on the 5 mandrel after the applying step.

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