FR3068761B1 - DEVICE FOR MOVING DECOUPLING BETWEEN A FLOATING PLATFORM AND A DRIVING - Google Patents

Abstract

The invention relates to a decoupling device (99) for movement between a floating platform (200) and a pipe (10) comprising at least one membrane (12) capable of being traversed by a fluid. The decoupling device (99) comprises: - a hollow head (100) capable of coming into engagement with the upper end of the pipe (10), the head (100) being secured to the floating platform (200), and - a plate (101) for suspending the pipe (10) by cables (14) extending at least along the length of the membrane (12), the cables (14) being connectable to the membrane (12) and suitable for passing through the head (100), the plate (101) being secured by a sliding connection (103) to the head (100) capable of moving the plate (101) along the axis (A-A ') of the fluid path, between two predetermined heights greater than the height of the upper end (100A) of the head (100).

Description

Device for decoupling movement between a floating platform and a pipe

The present invention relates to a pipe capable of being traversed by a fluid. The invention relates, for example, to the field of thermal energy of the seas (ETM) or any upstream installation of a large amount of cold water drawn for example to 200 meters deep and beyond.

There are marine thermal energy systems that produce electricity using the principle of a Carnot thermodynamic cycle based on the temperature difference between the surface waters and the deep waters. For example, the temperature of the surface waters can reach or even exceed 25 ° C, while deep waters that are deprived of sunlight have temperatures below 4 ° C.

Such ETM systems need a water pipe to suck up and up cool water. In order to suck the cold deep waters, the pipe generally has a long length, for example, greater than 600 meters (m), and may have a length of more than 1000 meters.

An ETM system comprises an evaporator which is fed with a hot fluid, for example surface water, through a supply pipe. The hot fluid is used in the evaporator to evaporate a working fluid circulating in a closed circuit. The working fluid, for example ammonia, is entrained in the closed circuit by a working fluid pump.

After passing through the evaporator, the hot fluid is discharged into the sea through a discharge pipe. The discharge pipe is sometimes referred to as the discharge pipe.

The working fluid evaporated in the high-pressure evaporator is fed to an expansion turbine which is connected to a current generator by a shaft. In the turbine, the working fluid is relaxed. Then, the working fluid is fed to a condenser to be cooled and condensed and then fed by the working fluid pump back to the evaporator. The condenser is fed by a cold fluid, which is deep seawater raised by the pipe. The cold fluid is driven by a cold fluid pump which brings the fluid to the condenser. Then, the heated fluid is discharged into the sea by a discharge pipe.

Such ETM systems generally comprise a floating platform and a fluid suction pipe adapted to be fixed to the platform. An upper portion of the fluid suction pipe is intended to be arranged in a well or "moon pool" of the floating platform and secured to the floating platform.

ETM systems are suitable for installation in tropical waters with a significant difference in temperature between shallow and deep waters. However, the seas of tropical regions can have strong currents, a large swell and be swept by cyclones.

It is known to connect suction lines to floating platforms by tensioner or "jumper" systems. These systems do not sufficiently limit the heave movements of the floating platform on the pipe in case of adverse environmental conditions. There is therefore a need for the fluid suction pipe to withstand such environmental conditions and, in particular, that the pipe can withstand the movements imposed by the floating platform.

An object of the present invention is to provide a fastening system to reduce the effects of the floating platform on the pipe. To this end, the present invention relates to a device for decoupling movement between a floating platform and a pipe, the pipe comprising at least one membrane adapted to be traversed by a fluid and the device comprising: - a clean hollow head to come in engagement with the upper end of the pipe, the head being secured to the floating platform, and - a suspension plate of the pipe by cables extending substantially at least along the length of the membrane of the pipe, the cables being connectable to the membrane, and adapted to pass through the head, the plate being secured by a sliding connection to the head, the sliding connection being able to move the plate, along the axis of travel of the fluid within the pipe, between two predetermined heights greater than the height of the upper end of the head.

The decoupling device according to the invention may comprise one or more of the following characteristics taken individually or in any technically feasible combination: the sliding connection comprises at least one jack whose stroke corresponds to the distance between the two predetermined heights; - The cylinder comprises a body fixed on the outer surface of the head and a movable piston secured to the suspension plate, adapted to pass through an upper flange of the head; - The head is adapted to be secured by a rigid connection to the floating platform; - The head is adapted to be secured by a ball joint connection to the floating platform; - The ball joint comprises at least one spherical ball corresponding to a support with elastomeric pads and / or interconnected cylinders; - The head has windows, arranged next evacuations fluid; the fluid recovery evacuations are rigid; the fluid recovery evacuations are flexible; and - the head forms a flotation element; The invention will be better understood on reading the description which will follow, given solely by way of example, and referring to the appended drawings, in which: FIG. 1 is a sectional view of part of a 2 is an enlarged view of zone II, identified in FIG. 1, showing a radial fastener connecting the membrane and a cable of the pipe of FIG. 1; FIG. FIG. 4 is a view in axial section of a ring and a cable passing through a loop of a ring of the pipe of FIG. 1. FIG. 5 is a perspective view of a lower portion of a fluid fluid conduit in which the diaphragm is not shown, FIG. 6 is a front view of FIG. inside of a ballast of the pipe is visible, - Figure 7 is a view from above of Figure 4 d part of a ring, and - Figure 8 is a sectional view of a head of a fluid line connected to a floating platform.

In the remainder of the description, the expression "substantially" will express a relationship of equality at plus or minus 10%.

Figure 1 is a schematic view in axial section of a pipe 10 according to the invention, deployed and in the operating position, adapted to be traversed by a fluid.

The pipe 10 is adapted to be traversed by a fluid and comprises at least: - a retractable membrane 12 configured to conduct the fluid between two distinct heights and whose outer surface is connectable to a plurality of radial fasteners, - a plurality of cables 14 extending substantially along the length of the membrane 12, each cable 14 being adapted to be ballasted by a lower end ballast of the pipe (as described below in connection with Figure 6), and suitable for being connected to the outer surface of the membrane 12 by at least one of the radial fasteners, - a plurality of rigid rings 16, capable of surrounding the membrane 12, each ring 16 comprising on its outer edge at least as many cable loops as there are cables 14.

Line 10 is, for example, a cold seawater pipe suitable for being part of a marine thermal energy system (ETM) which exploits the difference in surface and deep water temperature as explained. previously.

In the present description, the pipe 10 is adapted to be at least partially immersed and traversed by cold seawater.

It is defined in this description a vertical axis Z.

The membrane 12 defines an interior volume 17 for circulating the water through which the cold water of the deep water is raised.

Two cables 14A and 14B of the plurality of cables 14 and a ring 16 of the plurality of rings are shown in FIG.

The cables 14A, 14B are arranged outside the membrane 12, that is to say outside the internal volume 17 in which the cold water is able to circulate. The cable 14A is secured to the membrane 12 by a plurality of radial fasteners 18A-18D respectively at a plurality of attachment points 19A-19D. The cable 14B is attached to the membrane 12 by a plurality of radial fasteners 18E-18H respectively at a plurality of attachment points 19E-19H.

The cables 14 of the pipe 10 are evenly distributed angularly around the membrane 12 and extend along the length of the membrane 12.

The pipe 10 comprises, for example, a number of cables between ten and thirty. The pipe 10 comprises, for example, fifteen cables. The number of cables 14 is particularly adapted to vary depending on the diameter of the membrane 12.

The cables 14 are, for example, steel, polyester, nylon, polyethylene or a textile material.

Each ring 16 is arranged at a height different from that of a radial cable fastener 18.

The rings 16 of substantially circular section are located outside the membrane 12 and surround the membrane 12. In other words, the rings 16 are arranged outside the interior volume 17 of circulation of the water delimited by the membrane 12 and are regularly distributed along the length of the membrane 12.

The pipe 10 comprises between ninety and one hundred and two rings adapted to surround the membrane 12 along the length of the membrane 12. The pipe 10 comprises, for example, ninety-one rings. The number of rings is adapted to vary according to the diameter of the membrane 12.

Each cable 14A, 14B passes through cable loops 20 arranged on an outer edge of the rings 16.

In the following description, each radial fastener of the plurality of radial fasteners is designated by the general reference 18.

The membrane 12 has a substantially cylindrical shape with a circular base, extending along an axis A-A '. In the example shown in FIG. 1, the axis A-A 'of the membrane 12 is substantially parallel to the vertical direction Z.

The membrane 12 comprises a lower end (not shown in the figures) and an upper end 22 (as shown in Figure 8).

The terms "upper" and "lower" refer to the orientation of the vertical axis Z.

In the operating position of the pipe 10, the membrane 12 is, for example, able to conduct the cold seawater from the lower end of the membrane 12, located at a first height, to the upper end 22 membrane 12, located at a second height.

The membrane 12 is retractable in the axial direction A-A '. In other words, the membrane 12 is foldable in the axial direction A-A '.

Depending on the operating sites, the membrane 12 is capable of having a diameter of the order of 5 meters (m) and has a length, defined between the lower end and the upper end 22 of the membrane 12, included between 600 m and 1100 m.

The membrane 12 is made in one piece (i.e. without stacking sections).

Furthermore, the membrane 12 is made of a waterproof synthetic textile material. In addition, the membrane 12 has, for example, a basis weight of substantially 2.5 Kg / m 2, a thickness of 3.3 millimeters (mm) and a modulus of elongation of 40.5 meganewton (MN).

In connection with FIG. 2, at the attachment points 19, the membrane 12 has a plurality of pockets 24 disposed outside the inner volume 17 of the membrane 12. Each pocket 24 is formed by a portion 24A added to a outer surface 26 of the membrane 12.

Each pan 24A of each of the pockets 24 is, for example, sewn onto the outer surface 26 of the membrane 12.

Alternatively, the sections 24A of the pockets 24 are glued to the outer surface 26 of the membrane 12.

Each pocket 24 has a central orifice 28 opening, arranged, for example, in the center of the outer pan 24A of the pocket 24.

Each pocket 24 has a height of, for example, between 0.4 m and 0.5 m, in the axial direction A-A '.

The membrane 12 comprises a plurality of pocket belts 24 distributed evenly along the length of the membrane 12. Each pocket belt 24 comprises at least as many pockets 24 as cables 14. In addition, the membrane 12 comprises, between two successive rings 16, for example, three pocket belts 24 each extending along the membrane 12.

For example, a first pocket belt 24 includes the pockets 24 associated with the fasteners 18E of the cable 14B and 18A of the cable 14A. Another pocket belt 24 includes in particular the pockets 24 associated with the fasteners 18H of the cable 14B and 18D of the cable 14A.

Each pocket 24 of the membrane 12 is adapted to receive a slat 30. The slat 30 has, for example, a height of between 40 and 80 centimeters (cm) in the axial direction A-A ', a width between 10 and 30 cm, in a direction perpendicular to the radial direction of the membrane 12 and the axial direction A-A ', and a thickness of between 3 cm and 5 cm in a radial direction of the membrane 12.

Each pocket belt 24 comprises at least as many slats 30 as cables 14.

Each slat 30 is made of a rigid material, such as a composite material for example.

With reference to FIG. 2 and FIG. 3, each slat 30 comprises a body 31 and an insert 32 inserted in the body 31 of the slat 30. The insert 32 comprises a connection housing 34 enabling the connection of a fastener radial radial 18 to the membrane 12. Each insert 32 corresponds to an attachment point 19 of a radial attachment 18 to the membrane 12.

The connection housing 34 is adapted to be arranged facing the central orifice 28 of a pocket 24 for connecting a radial fastener 18 to the slat 30 through the central orifice 28 of said pocket 24.

The radial fasteners 18 connected to the cables 14 are suitable for supporting and stabilizing the shape of the membrane 12.

In particular, when the water is raised, the depression generated in the internal volume 17 of the membrane 12 causes a decrease in the internal volume 17 or, in other words, the flow section of the water. The deformation of the membrane 12 is in particular proportional to the depression present in the interior volume 17. The radial fasteners 18 then retain the membrane 12 to prevent its deformation and allow to maintain an optimum flow section of the water in the membrane 12 .

Each radial attachment 18 comprises a connector 36 adapted to be connected to the membrane 12 via a slat 30, a flange 38, also called sling, and a sliding bead 40 in which a cable 14 is intended to pass.

The flange 38 connects the connector 36 to the sliding bead 40 and extends in a radial direction to the membrane 12. The flange 38 has a radial length of the order of 0.6 meters for example. The radial length of the flange 38 may be different.

Each connector 36 is adapted to be fixed to a slat 30 of the membrane 12 through the central orifice 28 of a pocket 24. In particular, each connector 36 comprises a fixing head 36A adapted to be inserted into the housing 34 of A slat 30 through the central opening 28 of the pocket 24. In particular, the shape of the attachment head 36A and the shape of the housing 34 are complementary.

The connector 36 is connected to a first end 38A of the flange 38 by a first articulation 44. The first articulation 44 allows the rotation of the connector 36 with respect to the flange 38 along an axis B-B 'extending in a direction substantially tangent to the membrane 12.

The sliding bead 40 defines a through hole 45 through which a cable 14 is adapted to pass. Each cable 14 is freely movable in each of the sliding beads 40 in the axial direction A-A '.

The sliding bead 40 is connected to the second end 38B of the flange 38 by a second hinge 46. The second hinge 46 allows the sliding bead 40 to rotate relative to the flange 38 along an axis C-C 'also extending in a direction tangent to the membrane 12.

Alternatively, the membrane 12 comprises rods (not shown in the figures) extending along the length of the membrane 12. The rods have an elongated shape and have a length substantially equal to that of the membrane 12.

For example, the rods are trapped in recesses formed on the outer face 26 of the membrane 12.

In other embodiments, the rods are glued or welded to the outer face 26 of the membrane 12.

The pipe 10 comprises as many rods as cables 14.

The connector 36 of the radial fasteners 18 comprises a clamp, for example, a self-gripping clamp adapted to grip a portion of rod.

The number of radial fasteners is therefore adjustable as a function of the height of the radial fastener 18 along the length of the membrane 12. For example, the pipe 10 comprises a larger number of radial fasteners 18 in the upper part of the diaphragm. the membrane 12 in the lower part of the membrane 12.

In other words, the rods, whose length is substantially equal to that of the diaphragm 12, allow a flexibility of the positioning, along the Z axis, of the radial fasteners 18.

With reference to FIG. 4, each cable 14 passes through ring loops 20 arranged on the outer edge 55 of the rings 16.

Each ring 16 comprises at least as many loops 20 of cable as cables 14, evenly distributed angularly on its outer edge 55. This is particularly visible in Figure 4 which shows two loops 20 of cable, one of which 20T is shown in FIG. transparency, through which passes respectively a cable 14. The angle between each passing 20 of cable is equal to 360 / n! degrees where Π! is the number of cables 14. In the exemplary embodiment in which the pipe 10 comprises fifteen cables 14, each ring 16 comprises fifteen loops 20 of cable substantially angularly offset by 24 degrees relative to the center of the ring 16.

Each cable loop 20 is attached to the outer edge 55 of a ring 16 via a fastener 57.

As can be seen in FIG. 4, the fastening piece 57 has two fastening tabs 58, 60 (the fastening tab 60 is visible in FIG. 7) fastened to the outer edge 55 of the ring 16, parallel one to the other. report to the other. The cable loop 20 has a link 62 mounted in the space between the two fastening tabs 58, 60 and fixed to each fastening tab 58, 60. The cable loop 20 further comprises a body 64 defining a passage opening. cable 14 which extends radially with respect to the membrane 12 and outside the space defined between the two fastening tabs 58, 60.

The fastener 57 further comprises two rollers 66, 67 mounted in the space between the two fastening tabs 58, 60, spaced apart from one another in the axial direction A-A ', adapted to cooperate with each other. with a cable 14.

Each cable 14 passes through a cable 20 and is free to move in the cable 20 in the axial direction A-A 'of the pipe 10.

The rollers 66, 67 and the loops 20 of cable together form a cable guide 14, while limiting the friction of the guide on the cable 14.

As also visible in Figure 4, the rings 16 comprise a body 69 substantially circular and hollow. The rings 16 are for example resistant to the immersion pressure and are made of a rigid material, such as a metallic material.

The rings 16 have a proper ring thickness to vary with their height along the length of the membrane 12 so as to withstand the external pressure. In particular, the thickness of the body 69 of the rings 16 increases as a function of their depth in the seawater. More specifically, the pipe 10 comprises, for example, sixty-nine rings, each having a body thickness 69 of 8 mm. and an apparent mass of substantially 0.597 tonnes (t) and, for the greatest displacement depths of the membrane 12, twenty-two rings 16 each having a body thickness 69 of 9 mm and an apparent mass of substantially 0.701 t.

Alternatively, the rings 16 are said to be "equipressure" and are made, for example, of a plastic material filled with pressurized water.

In addition, the distribution of the rings 16 is adapted to vary according to their height along the length of the membrane 12. For example, the pipe 10 comprises a larger number of rings 16 in its upper part, it is in its part closer to the surface of the sea and fewer rings 16 in its lower part, that is to say in its part away from the surface. This is due to the fact that the upper part of the pipe 10 is subjected to more swell than the lower part.

The rings 16 support the cables 14 and guarantee the cylindrical shape of all the cables 14.

In addition, each cable 14 extends at least along the length of the membrane 12. The cables 14 have a lower end 14EI (visible in Figure 5) and an upper end 14ES (visible in Figure 8). For example, the cables 14 have a length of 1106 m.

With reference to FIG. 5, the lower end 14EI of each of the cables 14 is attached to a bottom end ballast 68 of the pipe 10.

The ballast 68 comprises two coaxial cylindrical crowns 70, 72 defining between them a predetermined space E.

The membrane 12 is sealingly attached to the inner ring 70 and the cables 14 are fixed on the outer ring 72 of the ballast 68 so as not to interfere with the attachment of the membrane 12 to the ballast 68.

The ballast 68 has, for example, a height of substantially 6.3 m, an outside diameter of substantially 6.2 m and an inside diameter of substantially 5 m. In addition, for example, the weight 68 is cast iron and has an apparent weight of 500 t. The apparent weight of the ballast 68 is greater than the sum of the forces applied on the ballast 68 when the pipe 10 has reached its operating depth. The lower end 1 4Ei of each cable 14 is provided with a fastener 74 fixed to an interface piece 76 integral with and projecting from the upper end of the outer ring 72 of the ballast 68.

The ballast 68 comprises at least as many interface pieces 76 as cables 14, regularly distributed angularly at the upper end of the ballast 68. In particular, the angle between each interface piece 74 is equal to 360 / n! where is the number of cables 14. Each interface piece 76 of the ballast 68 is substantially aligned in the axial direction A-A 'with the loops 20 of cable of the same cable 14.

The cables 14 are adapted to stabilize the shape of the pipe 10 for example in a substantially cylindrical shape and give the membrane 12 a shape, for example cylindrical, stable revolution. The weight 68 makes it possible to tension the cables 14 and to limit the deformations of the membrane 12 along the axis A-A '. The rings 16 make it possible to guarantee the cylindrical shape of the assembly of the cables 14 while avoiding their deformation in the radial direction and, consequently, make it possible to guarantee the cylindrical shape of the pipe 10.

According to the embodiment of FIG. 5, the pipe 10 further comprises flexible pipes 80.

In connection with Figure 6, each flexible pipe 80 has a lower end 82 and an upper end 83 (as shown in Figure 8). Each flexible pipe 80 is adapted to extend substantially at least along the length of the membrane 12. In particular, the length of the flexible pipes 80 is greater than that of the cables 14 and the membrane 12. The length of each flexible pipe 80 is, for example, greater than 1100 m, the length of the membrane 12, and equal, for example, to 1110 m.

The pipe 10 comprises, for example, three flexible pipes 80.

The number of cables 14 is proportional to the number of flexible pipes 80. In this case, the pipe 10 comprises five times more cables 14 than flexible pipes 80, or fifteen cables.

Each flexible pipe 80 comprises an internal passage intended to be traversed by at least one fluid such as seawater and / or a gas such as air.

When the flexible pipes 80 are filled with fluid, they are configured to be pressurized at a pressure of between 100 bars and 140 bars.

The flexible pipes 80 have for example an outer diameter of the order of 35 centimeters (cm) and an inner diameter of about 25.

The flexible ducts 80 are made, for example, of a composite material, such as a mixture of steel and / or carbon fibers. In particular, the flexible ducts 80 have, for example, an empty linear density of 85 kg / m and an empty apparent linear density of 40.7 kg / m. In addition, the flexible ducts 80 have, for example, an elongation modulus of elongation of 333 MN and a flexural modulus of substantially 16 kN / m2. The lower end 82 of each flexible pipe 80 is provided with a pipe 84 made of a rigid material. The tubing 84 is, for example, metallic. The lower distal end of the tubing 84 includes a stop 86.

Each tubing 84 is adapted to be received in a sleeve 88 or ballast housing 68, arranged in the space E defined between the inner ring 70 and the outer ring 72 of the ballast 68. In other words, the tubing 84 of each Flexible pipe 80 is able to slide in a sheath 88 of ballast 68.

The ballast 68 further comprises removable stoppers 90 arranged respectively at the upper end of each of the sleeves 88 and adapted to cooperate with the abutment 86 of the pipe 84 of each of the flexible pipes 80 to prevent the flexible pipes 80 from escaping. sheaths 88.

Cast iron plates are, for example, arranged in the space E of the ballast 68 between the sleeves 88.

According to one embodiment, the flexible ducts 80 are, for example, hydraulically connected to each other so as to balance the pressures of the fluid passing through the internal passage of each of the flexible ducts 80. Channels (not shown in the figures) connect by For example, the internal passages of the flexible pipes 80. These channels are connected, for example, to the pipes 84 of the flexible pipes 84. The channels are, for example, flexible.

In addition, according to an embodiment not shown, one of the flexible pipes 80 comprises a dip tube inserted into the flexible pipe 80 by the upper end of the flexible pipe 80 adapted to perform a drain of the flexible pipes 80.

Thanks to the presence of the channels connecting the internal passages of each of the flexible pipes 80, the emptying of the flexible pipes 80 via the dip tube is easily achieved, in particular by air injection when the pipe 10 is raised to the surface for maintenance.

With reference to FIG. 7, showing a portion of a ring 16, the body 69 of the ring 16 comprises tubular portions 92 and receiving portions 94 of the flexible ducts 80. The tubular portions 92 connect the portions of the ring. welcome 94 between them. Each receiving portion 94 has a shape complementary to that of a flexible pipe 80 for example hemispherical open outwardly with respect to the membrane 12 surrounded by the ring 16.

The rings 16 further comprise a removable part 96 adapted to cooperate with the receiving portion 94 of the body 69 of the ring 16 to form a mounting block 97 of a flexible pipe 80. Each mounting block 97 delimits a housing 98 whose shape is adapted to that of a flexible pipe 80. In this case, each housing 98 is cylindrical in shape and has a diameter substantially equal to that of a flexible pipe 80.

The recess blocks 97 of one or more rings 16 located at the lower end of the pipe 10 delimit a housing 98 whose diameter is substantially the same as that of the pipe 84 of the flexible pipes 80 and are adapted to enclose each a rigid tubing 84.

Each ring 16 comprises at least the same number of embedding blocks 97 as flexible pipes 80. Thus, each ring 16 has, for example, three embedding blocks 97 regularly distributed on the circumference of the ring 16. More precisely , the recess blocks 97 of a ring 16 are angularly spaced from each other by an angle equal to 360 / n2 where n2 is the number of flexible ducts 80. In the embodiment in which the pipe 10 comprises three flexible pipes 80 spaced 120 degrees relative to each other, the built-in blocks 97 are also spaced 120 degrees from each other. In particular, n2, the number of flexible pipes 80 is strictly less than Π! the number of cables 14.

Thus, according to this example, each flexible pipe 80 is interposed between two adjacent tubular portions 92 of the ring 16, that is to say between the inner edge and the outer edge of each tubular portion 92, while the cables 14 pass outside the tubular portions 92, that is to say outside the outer edge of the tubular portions 92.

Alternatively, the receiving portions 94 of the embedding blocks 97 are arranged outside the ring 16. In other words, the receiving portions 94 project from the outer edge 55 of the ring 16 and are oriented in a direction opposite to the membrane 12.

Thus, each flexible pipe 80 passes outside the outer edge 55 of the rings 16 (i.e. outside the ring 16).

The flexible pipes 80 when pressurized are able to structurally stabilize and stiffen the pipe 10 allowing good resistance to the effects of the current.

The flexible pipes 80, combined with the cables 14 and the rings 16 are able to constitute an exoskeleton of the pipe 10. More specifically, the assembly formed by the cables 14, the rings 16 and the flexible pipes 80 form a cage of the pipe 10 (ie a cage outside and around the membrane 12).

In particular, the apparent weight of the ballast 68 is distributed between the cables 14 which provide the longitudinal rigidity of the pipe 10 and the membrane 12.

In addition, the fitting of the pressurized flexible pipes 80 in the rings 16 makes it possible to create a beam-ladder structure ensuring the rigidity of the pipe 10. The flexible pipes 80 limit the radial deformation of the pipe 10, once the pipe 10 has reached its operating depth. The architecture of the pipe 10 according to the invention facilitates the flow of water in the pipe 10. Thus, during its ascent into the inner volume 17 of the membrane 12, the cold water rises freely without meeting obstacle. This makes it possible to reduce the pressure drops and to optimize the ascent rate. In particular, the pipe 10 is intended to increase a flow substantially equal to 100,000 m3 / h.

In addition, thanks to the structure of the pipe 10 described above, the interior volume 17 is maintained even in the presence of adverse weather conditions.

In connection with FIG. 8, a decoupling device 99 for movement between a floating platform 200 and a pipe 10 is described.

The floating platform 200 to which line 10 is connected is part of the ETM system and is adapted to float on the sea surface. The floating platform 200 includes a working bridge 200A.

The decoupling device 99 comprises a hollow head 100 for recovering fluid, in this case cold water brought up by the pipe 10, capable of coming into engagement with the upper end of the pipe 10. The head 100 is suitable for to be secured to the floating platform 200.

In one embodiment, the head 100 is adapted to be secured to the floating platform 200 by a link 102. The link 102 is, for example, integral with the bridge 200A of the floating platform 200.

At least a part of the head 100 is intended to be suspended via the link 102 in an opening hole 214 formed in the center of the floating platform 200. The hole 214 formed in the floating platform 200 is also called a "well" or , in English, moon-pool. The hole 214 has a substantially circular section and has a diameter greater than that of the inner diameter of the head 100. For example, the diameter of the hole 214 is substantially equal to 16 m.

The decoupling device 99 further comprises a plate 101 for suspending the pipe 10 by the cables 14 of the pipe 10. In other words, the upper ends 14Es of the cables 14 are integral with the plate 101.

According to one embodiment, the upper ends 83 of the flexible pipes 80 are also integral with the suspension plate 101. An upper portion of each flexible pipe 80 is provided with a tubular frame (not shown in the figures). For example, each tubular reinforcement measures between 0.5 m and 1 m. More specifically, the tubular reinforcement of the flexible ducts 80 are supported in a porch (not shown in the figures) integral with the plate 101.

The suspension plate 101 is secured to the head 100 by a sliding connection 103. The sliding link 103 is able to move the plate 101, along the path A-A 'of the cold water within the pipe 10 between two predetermined heights greater than the height of the upper end 100A of the head 100. Thus, in the example of Figure 8 in which the cold water is raised in the pipe 10 in the axial direction A-A ' , the plate 101 is slidably mounted along the axis A-A 'above the head 100.

The hollow head 100 has a substantially cylindrical shape and delimits an internal passage 100C.

The upper part 104 of the head 100 is formed of a simple ferrule 104A, that is to say a single ferrule, and a flange 104B which extends radially outwardly of the head 100 to from the upper end of the single ferrule 104A. The single ferrule 104A and the flange 104B are arranged in the hole 214 of the floating platform 200 above the draft.

The single ferrule 104A has, for example, an outer diameter of 12 m.

The diameter of the hole 214 of the floating platform 200 is 50% to 75% larger than the diameter of the single ring 104A of the head 100.

In addition, the ball joint 102 is, for example, connected to the flange 104B of the head 100 of the decoupling device 99.

The upper surface of the flange 104A forms the upper end of the head 100.

The sliding link 103, intended to move the suspension plate 101 along the axis A-A 'above the upper end 100 A of the head 100, comprises actuators, for example cylinders 110 associated with a battery. accumulators (not shown in the figures), for example hydraulic cylinders. The accumulator battery is attached to the outer surface of the single ferrule 104A of the head 100. For example, the accumulator battery has a volume of substantially 27m3.

The cylinders 110 each comprise a body (not shown in the figures), a movable piston 11 OA integral with the suspension plate 101 clean through an orifice 111 formed in the collar 104B of the head 100, and a 110B accumulator fixed to the surface outside the head 100, on the outer surface of the single ring 104A of the head 100.

The distance between the two predetermined heights greater than the height of the upper end 100A of the head 100 between which the plate 101 is able to move defines the stroke of the cylinder 110.

The suspension plate 101 thus forms an anti-heave device adapted to limit the dynamic effects of the heavy heave of the floating platform 200 on the pipe 10 due to the swell by resuming or releasing a stroke of the pipe 10 along the axis A-A '.

The stroke of the cylinder 110 is defined according to the dynamics of the pipe 10 relative to the heave imposed by the floating platform 200. For example, the stroke of each cylinder 110 is between ± 1 m and ± 4 m. Specifically, the ± 1m stroke is required during extreme operating conditions and the ± 4m stroke required during cyclonic conditions.

In addition, the cylinders 110 have for example a diameter of substantially 411 mm. Moreover, the cylinders 110 have for example a nominal pressure of 151 bar.

The lower portion 106 of the head 100 is formed of a double ferrule 106A comprising two concentric cylinders forming a floating element of the head 100 and providing buoyancy to the pipe 10. The double ferrule 106A is adapted to extend to at the lower end of the movable piston 110B when the latter is at rest. The double ring 106A creates a hydrostatic thrust of the order of 850 t to 1200 t for example. The head 100 of the decoupling device therefore forms a flotation element.

The cables 14 and the flexible pipes 80 disposed outside the membrane 12, as explained above, pass through the head 100 of the decoupling device 99 from the lower end 100B of the head 100 and beyond the upper end. 100A of the head 100 to the plate 101. The upper end 22 of the membrane 12 and an upper end ring 16 of the pipe 10 surrounding the upper end 22 of the membrane 12 are housed in the double ferrule 106A of the pipe 10. The upper end ring 16 situated inside the head 100 seals between the lower end 106 of the head 100 and the inner surface of the double ferrule 106A of the head 100 .

In some exemplary embodiments, an inflatable seal 107 is, for example, arranged between the outer edge 55 of the upper end ring 16 and the inner surface of the head 100 to seal between the inner surface of the double ferrule 106A of the head 100 of the decoupling device 99 and the upper end 22 of the membrane 12. The seal 107 is, for example, integral with the outer edge 55 of the ring 16 and movable with the ring 16. The seal inflatable 107 is for example an O-ring ..

In the event of adverse weather conditions, especially in the case of cyclonic conditions, the seal 107 is deflated, which allows free movement of the upper end ring 16 in the head 100.

In particular, when the swell is greater than 1.7 m, the upwell of cold water is suspended by an operator (i.e. stopped momentarily). Thus, under these conditions, it is no longer necessary to seal between the membrane 12 and the head 100.

In certain exemplary embodiments, the head 100 further comprises a bellows mechanism 108 arranged between the outer surface 26 of the membrane 12 and the upper end ring 16 for sealing between the membrane 12 and the ring 16.

In addition, the lower portion 106 of the head 100 comprises, for example, four windows 116 formed in the double ferrule 106A, intended to be connected respectively to four evacuations 118 of cold water integral with the floating platform 200, also called "headlines >>.

The evacuations 118 have, for example, a diameter of 2.25 m.

Furthermore, in the present embodiment in which the head 100 is connected to the floating platform by a ball joint 102, the evacuations 118 are flexible. In particular, the head 100 of the decoupling device 99 being connected to the floating platform, the evacuations 118 connected to the head 100 undergo only one movement along the three axes of rotation which is well accepted in view of their flexibility. The upper end 22 of the membrane 12 is located substantially at the level of the evacuations 118. In other words, the upper end 22 of the membrane 12 is located at the windows 116 arranged in the double shell 106A located opposite the evacuations 118.

Pumps 120, integral with the floating platform 200, are arranged in the evacuations 118 to transfer the cold water raised by the pipe 10 into the evacuations 118. More specifically, the pumps 120 are for example arranged above the double ferrule 106A forming the lower portion 104 of the head 100. The suction pipe of the pumps 120 is housed in the space defined between the two rings of the double ring 106A of the head 100.

The pumps 120 create a driving force to raise the cold water through the membrane 12 by lowering the water level in the internal volume 17 delimited by the membrane 12 by surface pumping creating a depression of 300 to 350 millibars. The depression at the start of the upwell of cold water is generated progressively. Similarly, in case of decoupling, when stopping the upwelling, the depression is gradually stopped.

According to one embodiment, the link 102 is a ball joint. The ball joint is for example a spherical ball joint enabling rotation of the floating platform 200 around the three axes of rotation at an angle of substantially ± 9 degrees.

The spherical ball joint allowing the rotation of the pipe 10 along the three axes of rotation cancels the transmission of the pitching, rolling and yawing movements of the floating platform 200 to the pipe 10.

The connection 102 ball connecting the head 100 of the decoupling device 99 to the floating platform 200 comprises for example an elastomeric pad support or interconnected cylinders. The cylinders are, for example, hydraulic cylinders and, at least, three in number.

The suspension plate 101 and the ball joint 102 make it possible to limit the transmission of the movements of the floating platform 200 to the pipe 10.

According to another embodiment, the link 102 is rigid. The upper end 100A of the head 100 is intended to be rigidly connected to the floating platform 200. In other words, the flange 104B of the head of the anti-heave device is rigidly fixed to the bridge 200A of the floating platform 200. In this case the suction evacuations 118 are rigid.

In this case, in some embodiments, the hole 214 is sealingly closed around the head 100. Such an arrangement increases the buoyancy of the pipe 10 and allows the pumps 120 and the cold water outlets 118 to be located out of water.

In some embodiments, the floating platform 200 comprises a storage drum 12 of the membrane, of substantially 14.5m in diameter, for example, and cable storage reels 14 and flexible pipes 80 arranged on the deck of the platform floating 200.

In some embodiments, the head 100 comprises mounting stations of the pipe 10 opening into the internal passage 100C of the head 100 of the decoupling device 99, from which the pipe 10 is mounted by operators.

A method of mounting the pipe 10 and the decoupling system 99 from the floating platform 200 is described in the following description.

The head 100 of the decoupling device 99 on which is mounted the suspension plate 101 of the pipe 10 is first introduced into the hole 214 of the floating platform 200 and suspended from the deck 200A of the platform 200 via the ball joint 102 In a variant, the head 100 is rigidly fixed to the platform 200.

The rings 16 are stacked on the deck 200A of the floating platform 200, and, from the deck 200A of the floating platform 200, each cable 14 is passed through the cable loops 20 of the rings 16.

In addition, on the floating platform 200, each cable 14 is threaded into each sliding bead 40 of each radial fastener 18 connecting it to the membrane 12.

Then, still on the floating platform 200, the lower ends of the membrane 12, cables 14 and flexible pipes 80 are connected to the ballast 68. In particular, each pipe 84 of each of the flexible pipes 80 is introduced into a sleeve 88 of the ballast 68 and removable retainers 90 are attached to the upper ends of the sleeves 88. During this step of mounting the pipe 10, the flexible pipes 80 are not pressurized and therefore are not in tension.

The storage drum of the membrane 12 and the reels for storing the cables 14 and the flexible pipes 80 are associated with winches and set in motion in a synchronized manner.

The membrane 12, the ballast 68, the cables 14 and the flexible pipes 80 are then unrolled and lowered synchronously in the head 100. In particular, during this step, the unwinding of the reels for storing the flexible pipes 80 is controlled by hydraulic motors which maintain a constant tension of the flexible pipes 80, substantially between 5 t and 20 t by flexible pipe 80. In addition, the three flexible pipes 80 are each driven by a crawler mechanism also called "chaser" controlling their unwinding speed. The crawler mechanism is arranged on the deck 200A of the floating platform 200 and is integral with the collar 104B of the head 100. One of the crawler mechanisms defines the unwinding speed of the flexible pipes and drives the other crawler mechanisms.

The unwinding speed of the flexible pipes 80 defines the unwinding speed of the winches associated with the reels for storing the cables 14. The unwinding speed of the winches is regulated by speed controllers.

In addition, during this step, the stops 86 of the pipes 84 of the flexible pipes 80 are in the high position, that is to say that they come into contact with the removable retainers 90 of the sleeves 88 of the weight 68 to create a tension on the flexible pipes 80 during assembly of the pipe 10. In particular, during this step, the flexible pipes 80 with the cables 14 support a portion of the weight of the ballast 68 to be in tension.

As the course of the membrane 12 progresses, the slats 30 are inserted into the pockets 24 of said membrane 12 from the deck 200A of the floating platform 200. From the beginning of the descent of the ballast 68, of the membrane 12, cables 14 and flexible pipes 80 in the head 100 of the decoupling device 99, the rings 16 are lowered inside the head 100 and stored in the head 100 in a single storage battery. The radial fasteners 18 are also lowered into the head 100 and stored at the mounting stations opening into the internal passage 100C delimited by the hollow head 100. The rings 16 are threaded around the membrane 12.

As the membrane 12 descends into the head 100, the radial fasteners 18 are connected to the slats 30 of the membrane 12 by operators from the mounting stations opening into the internal passage 100C of the head 100 of the decoupling device 99.

In addition, as they descend into the head 100, the flexible pipes 80 are clamped in the embedding blocks 97 of the first lower ring 16 of the ring stack 14 stored in the head 100 and in the blocks. recess 64 of the other rings 16 of the stack of rings. To do this, each removable part 96 cooperates with each receiving portion 94 of the body 69 of the rings 16. These operations are also performed from the mounting stations by at least two operators by flexible pipe 80.

Once the flexible ducts 80 are clamped in the recess blocks 97 of a ring 16, the ring 14 is detached from the head 100 and lowered out into the head 100. The rings 14 are thus released one by one from the head 100 in which they are stored.

Finally, when the ballast 68 has reached the operating depth of the pipe 10, the storage reels of the cables 14 and the flexible pipes 80 and the unwinding drum of the membrane 12 are stopped. At the end of this step, the length of the flexible pipes 80 is greater than that of the cables 14.

Then, the upper ends 83 of the flexible pipes 80 and the upper ends 14Es of the cables 14 are connected to the suspension plate 101.

The flexible pipes 80 are then filled with water to balance the pressure inside the flexible pipes 80 and pressurized with air to give them stiffness. Finally, the inflatable seal 107 located between the upper end ring 16 of the pipe 10 and the inner surface of the head 100 is inflated.

Once the assembly of the pipe 10 has been completed, the flexible pipes 80 are able to slide freely in the sleeves 88 of the ballast 68 and the apparent weight of the ballast 68 is supported by the cables 14 and the membrane 12. The cables 14 are also free movement either at the level of the sliding beads 40, radial fasteners 18 or cable loops of the rings 16.

The assembly of the pipe 10 and the decoupling system 99 is performed, for example, for a period of time less than a weather window not exceeding 78 hours. In particular, the mounting of the pipe 10 and the decoupling system 99 is able to be carried out in 72 hours.

The method of mounting the pipe 10 and the decoupling system 99 is particularly simple. It allows in particular to mount the pipe 10 in situ on the operating area, from the floating platform 200, and this continuously.

Another embodiment not shown in the figures of a decoupling device 99 is described below. This embodiment is described as an alternative to the embodiment of FIG. 8.

The decoupling device 99 comprises the hollow head 100 and a clean float to be housed and fixed to the head 100 by a flexible fastening system. The float is also connected to the deck 200A of the floating platform 200 by a first flexible link, of a length equal to a multiple, for example five to ten times, of the predetermined heave height and secondly at the end. upper head 100 by a second link.

In case of unfavorable sea conditions, that is to say, when the floating platform 200 is subjected to a heave such that upwelling is impossible, the head 100 is disconnected from the floating platform 200 and the float s extracted from its housing in the head 100 to remain at the surface while the head 100 disconnected from the platform 200 sinks into the hole 214. With the first flexible link connecting the float to the floating platform 200, the float filters the movements heave platform 200 and limits the effects of heave platform 200 on the pipe 10, because the link that connects to the head 100 is also flexible.

Claims (10)

1. - Device for decoupling (99) movement between a floating platform (200) and a pipe (10), the pipe (10) comprising at least one membrane (12) adapted to be traversed by a fluid, characterized in that the device (99) comprises: - a hollow head (100) adapted to engage the upper end of the pipe (10), the head (100) being secured to the floating platform (200), and - a plate (101) for suspending the pipe (10) by cables (14) extending substantially at least along the length of the membrane (12) of the pipe (10), the cables (14) being connectable to the membrane ( 12) and adapted to pass through the head (100), the plate (101) being secured by a sliding connection (103) to the head (100), the sliding connection (103) being able to move the plate (101), along the axis of the path of the fluid within the pipe (10), between two predetermined heights greater than the height of the upper end (100A) of the head (100). 2. - decoupling device according to claim 1, wherein the sliding connection (103) comprises at least one jack (110) whose stroke corresponds to the distance between the two predetermined heights. 3. - decoupling device according to claim 2, wherein the cylinder (110) comprises a body (110A) fixed on the outer surface of the head (100) and a movable piston (110B) integral with the plate (101) of suspension, adapted to pass through an upper flange (104B) of the head (100). 4. - decoupling device according to any one of claims 1 to 3, wherein the head (100) is adapted to be secured by a connection (102) rigid to the floating platform (200). 5. - decoupling device according to any one of claims 1 to 3 wherein the head (100) is adapted to be secured by a connection (102) ball to the floating platform (200). 6. - decoupling device according to claim 5, wherein the connection (102) ball comprises at least one spherical ball corresponding to a support with elastomeric pads and / or interconnected cylinders. 7. - decoupling device according to any one of the preceding claims wherein the head (100) has windows (116), arranged opposite evacuations (118) of the fluid. The decoupling device of claim 4 and claim 7, wherein the fluid recovery evacuations (118) are rigid. The decoupling device according to claim 5 or 6 and claim 7, wherein the fluid recovery evacuations (118) are flexible. 10. - decoupling device according to any one of the preceding claims, wherein the head (100) forms a flotation element.