Clamping pad with maximised flexibility for a device for holding a fluid transport tube by means of friction

Abstract

The invention relates to a clamping pad (4) for a device for holding a tube (6) by means of friction, comprising a steel casing (8) in which a cavity (10) provided with a bottom (12) and two lateral edges (14) is formed. The cavity is filled with a flexible polymer material (16) in which a plurality of gripping bars (18a, 18b) are housed. The lateral gripping bars (18a) each have a different geometrical shape from the other gripping bars (18b) and each have a lateral face (22a) having a rounded profile matching the profile of the corresponding lateral edge of the cavity and which is in sliding contact therewith. Means (24) are provided for confining the flexible material in the cavity between the gripping bars at their respective contact face.

Description

Description Title of the invention: Clamping pad with maximum flexibility for a friction-based retention device for a fluid transport tube Technical Field

[0001] The invention relates to the general field of frictional holding of a tube used for the transport of fluids on the seabed or lakebed, particularly in the underwater hydrocarbon production industry (oil and gas), but also for the transport of other fluids such as fresh water, CO2, hydrogen, etc.

[0002] One application of the invention relates to the securing of a pipeline for the underwater transport of fluids within a laying tower. However, the invention can also be applied to the laying of other tubes used in this industry, such as flexible hoses or umbilicals, or even submarine cables used in the fields of telecommunications and power transmission. Previous technique

[0003] Various methods are known in the subsea oil and gas industry for installing rigid and flexible pipelines at sea, such as S-lay, J-lay, and coil-lay.

[0004] In each of these installation methods, the pipeline is suspended as a catenary between the laying vessel and the seabed, under the tension of its own weight. The weight of the catenary suspended between the laying vessel and the seabed is supported by a holding device on board the vessel, which applies a restraining force to the pipeline (for example, a vertical tensioner or VLS for "Vertical Laying System"). When laying large-diameter pipelines in deep water, the holding device must therefore be designed to withstand a weight of several hundred tons.

[0005] One known solution involves holding the pipeline by means of a plurality of clamps arranged one above the other in the pipeline laying tower, each clamp supporting a section of The load acting on the pipe. In these holding devices, each clamp is more precisely composed of several clamping pads evenly distributed around the axis of the pipe and actuated by cylinders to produce a radial load on the pipe to be held. Another solution consists of holding the pipe by one or more tensioners made up of motorized tracks fitted with friction pads and pressed on either side of the pipe.

[0006] There are various clamping pad designs for these clamps. For example, see publications WO 2010 / 061280, US 3,778,094 and GB 1,506,407, which describe clamping pads comprising a rigid housing containing a deformable element. The outer wall of this deformable element is concave, with a radius of curvature approximately equal to the average radius of the tube being held. The deformable element consists of a plurality of gripping bars extending along the longitudinal axis of the tube being held. This deformable element thus has a composite structure that allows it to adapt to variations in the cross-section of the tube being held.

[0007] Although effective, it is necessary to reinforce the robustness of these clamping pads. In particular, the stress levels around the gripping bars closest to the lateral edges of the rigid housing are such that fatigue cracks may be observed in service. Description of the invention

[0008] The invention therefore aims to provide a clamping pad for a device for retaining a tube by friction which does not present the aforementioned disadvantages.

[0009] This objective is achieved by means of a clamping pad for a friction-based tube retention device used for transporting fluids on the seabed or lakebed. The pad comprises a steel casing in which a cavity is formed, having a bottom and two opposing lateral edges designed to extend along the longitudinal axis of the tube. The cavity is filled with a flexible polymer material in which are housed a plurality of gripping bars distributed between the two lateral edges of the cavity. These bars extend along the longitudinal axis of the tube and each has a contact face designed to grip the tube. contact with an external surface of the tube, and in which, according to the invention: - the lateral gripping bars that are closest to the two lateral edges of the cavity each have a different geometric shape from the other gripping bars and each have a lateral face opposite a lateral edge of the cavity which has a rounded profile conforming to the profile of the corresponding lateral edge of the cavity and which is in sliding contact with it in order to laterally confine the flexible material within the cavity, and - the skate further includes means for confining the flexible material in the cavity between the gripping bars at their respective contact faces.

[0010] The clamping pad according to the invention is notable in particular because the lateral gripping bars closest to the two lateral edges of the cavity each have a different geometric shape from the other gripping bars. Since the lateral gripping bars have the greatest displacement from the neutral position to reach the smallest and largest diameters in the range of pipes, achieving a sliding contact between the lateral edge of these bars and the cavity avoids a problem of very high shear rate in the polymer layer between these two contacting surfaces.

[0011] According to one embodiment, the skate includes semi-rigid polymer plugs arranged between the gripping bars at their respective contact faces in order to confine the flexible material in the cavity between the gripping bars.

[0012] According to another embodiment, the skate comprises strips of rolled steel embedded in the flexible material between the gripping bars at their respective contact faces in order to confine the flexible material in the cavity between the gripping bars.

[0013] According to yet another embodiment, the gripping bars are in contact with each other at their respective contact face in order to confine the flexible material in the cavity between the gripping bars.

[0014] According to yet another embodiment, the skid includes flexible metal bellows welded between the gripping bars at their respective contact faces in order to confine the flexible material in the cavity between the gripping bars.

[0015] According to yet another embodiment, the flexible material is confined in the cavity by a more rigid polymer material which completely envelops the flexible material.

[0016] Preferably, the central gripping bars located between the lateral gripping bars each have a portion embedded in the flexible material which is rounded so as to mitigate the high stress concentrations in the flexible material at the interface with the casing.

[0017] Preferably, the gripping bars also have at least one anchoring notch in the flexible material on their opposite lateral faces. These anchoring notches improve the anchoring of the gripping bars in the flexible material.

[0018] The lateral edges of the cavity can be covered with a layer of thermoplastic polymer with a low coefficient of friction.

[0019] The skid may further include a cylinder having a rod intended to be arranged in a radial direction to the tube and at the end of which the casing is mounted.

[0020] Preferably, the contact face of the gripping bars which is intended to come into contact with the outer surface of the tube has grooves, knurling or machining in order to improve the grip of the sliding surface of the pipe.

[0021] The invention also relates to a device for holding a tube by friction, comprising two clamping pads as defined above which are arranged opposite each other with respect to the axis of the tube.

[0022] The invention also relates to a device for holding a tube by friction, comprising at least three clamping pads as defined above, said pads being spaced angularly apart from each other in a regular manner.

[0023] Brief description of the drawings

[0024] [Fig. 1 A] to [Fig. 1 C] Figure 1 A, Figure 1 B, and Figure 1 C represent different configurations of a holding device according to the invention.

[0025] [Fig. 2] Figure 2 represents a perspective view of a clamping pad of the retaining device according to the invention.

[0026] [Fig. 3] Figure 3 is a partial cross-sectional view of a clamping pad according to a first embodiment of the invention.

[0027] [Fig. 4] Figure 4 is a partial cross-sectional view of a clamping pad according to an alternative embodiment of the first embodiment of the invention.

[0028] [Fig. 5] Figure 5 is a partial cross-sectional view of a clamping pad according to a second embodiment of the invention.

[0029] [Fig. 6] Figure 6 is a partial cross-sectional view of a clamping pad according to a third embodiment of the invention.

[0030] [Fig. 7] Figure 7 is a partial cross-sectional view of a clamping pad according to a fourth embodiment of the invention.

[0031] [Fig. 8] Figure 8 is a partial cross-sectional view of a clamping pad according to a fifth embodiment of the invention. Description of the implementation methods

[0032] The invention relates to the friction-based securing of a pipe used for transporting fluids on the seabed or lakebed, particularly in the subsea hydrocarbon production industry. Specifically, it relates to securing a pipeline for the subsea transport of fluids, such as those shown in Figures 1A to 1C, within a pipe-laying tower, and also to securing a pipeline using one or more tensioners consisting of motorized tracks fitted with friction pads and pressed against both sides of the pipeline.

[0033] Figures 1A to 1C show different possible configurations of a pipe support device in a laying tower.

[0034] The retaining device 2a of figure 1 A thus comprises six clamping pads 4 which are spaced angularly apart from each other at regular intervals around an axis XX of a pipe 6a having a diameter Da.

[0035] The retaining device 2b of Figure 1 B also includes six clamping pads 4 which are regularly spaced angularly from each other around an axis XX of a pipe 6b having a diameter Db (less than the diameter Da of the pipe 6a of Figure 1 A).

[0036] Finally, the retaining device 2c of figure 1C includes three clamping pads 4 which are spaced angularly apart at regular intervals around an axis XX of a pipe 6c having a diameter De (less than the diameters Da and Db of the pipes in figures 1A and 1B).

[0037] Of course, it is possible to imagine that the retaining device according to the invention may alternately comprise four or eight clamping pads. Similarly, the clamping device could comprise several sets of at least three clamping pads that are offset from one another along the axis of the pipe.

[0038] According to the invention, as shown in figures 2 and 3, each clamping pad comprises a steel casing 8 in which a cavity 10 is formed.

[0039] The cavity 10 is provided with a base 12 and two opposing lateral edges 14 which are designed to extend along a longitudinal axis XX of the pipe. This cavity 10 is filled with a flexible polymer material 16, for example polyurethane. Preferably, this will be a polyurethane having a hardness of approximately 40 to 70 Shore A.

[0040] Inside this flexible material 16 is housed a plurality of gripping bars 18a, 18b which extend along the longitudinal axis XX of the pipe and which are distributed between the two lateral edges 14 of the cavity 10.

[0041] More specifically, the clamping pad includes two lateral gripping bars 18a (namely those closest to the two lateral edges) 14 of the cavity 10), and several central gripping bars 18b located between these two lateral gripping bars 18a.

[0042] The central gripping bars 18b of the clamping pad each have a (major) part which is embedded in the flexible material 16, and an emerged part which is substantially flat to come into contact with an external surface of the pipe 6. The embedded part of the central gripping bars is glued to the flexible material 16.

[0043] Advantageously, the contact face of the gripping bars 18a, 18b which is intended to come into contact with the outer surface of the pipe 6 has grooves, knurling or machining in order to improve the grip of the sliding surface of the pipe.

[0044] According to the invention, the lateral gripping bars 18a each have a different geometric shape from the other central gripping bars 18b. In addition, they each have a lateral face 22a opposite a lateral edge 14 of the cavity 10 which has a rounded profile following the profile of the corresponding lateral edge of the cavity and which is in sliding contact with it.

[0045] Furthermore, according to the invention, means are provided for confining the flexible material 16 in the cavity 10 between the gripping bars 18a, 18b at the level of their respective contact face.

[0046] Since the lateral gripping bars 18a have the greatest displacement from the neutral position to reach the smallest and largest diameters in the range of pipes to be held, the best way to mitigate the shear rate in the lateral part of the soft material bed is to achieve sliding contact between the lateral face of the lateral gripping bars and the cavity.

[0047] Furthermore, since the soft polymer of the flexible material filling the cavity is strongly compressed during radial compression of the skate, it is necessary to confine it between the skate cover and the gripping bars.

[0048] To this end, in the first embodiment shown in Figure 3, the skate 4-1 further comprises semi-rigid polymer plugs 24 which are arranged between the adjacent gripping bars 18a, 18b at their respective contact face in order to confine the soft material in the cavity between the gripping bars.

[0049] For example, when the flexible material 16 is a polyurethane with a hardness of about 40 Shore A, the plugs 24 can be made of polyurethane with a hardness of about 90 Shore A.

[0050] In the variant embodiment of this first embodiment which is represented in figure 4, the faces opposite the gripping bars 18a, 18b of the skate 4-2 which receive the plugs 24 have grooves 24a allowing to improve the anchoring of the plugs.

[0051] In the second embodiment shown in Figure 5, the skate 4-3 includes strips of rolled steel 26 which are embedded in the soft material 16 between the gripping bars 18a, 18b at their respective contact face in order to confine the soft material in the cavity between the gripping bars.

[0052] In the third embodiment shown in Figure 6, the gripping bars 18a, 18b of the skate 4-4 are in contact with each other at their respective contact face in order to confine the flexible material 16 in the cavity between the gripping bars.

[0053] In the fourth embodiment shown in Figure 7, the skate 4-5 includes flexible metal bellows 28 which are welded between the gripping bars 18a, 18b at their respective contact faces in order to confine the flexible material in the cavity between the gripping bars.

[0054] In the fifth embodiment shown in Figure 8, the soft material 16 of the skate 4-6 is confined in the cavity by a more rigid polymer material 30 which completely envelops the soft material 16.

[0055] For example, if the soft material 16 is a polyurethane with a hardness of about 40 Shore A, the more rigid material 30 could be a polyurethane with a hardness of about 90 Shore A.

[0056] As shown in Figure 8, the lateral edges of the cavity 10 can be covered with a layer 32 of low coefficient of friction thermoplastic polymer, for example Teflon®.

[0057] Preferably, the embedded part of the central gripping bars 18b has a cross-sectional profile 20 which is rounded in order to attenuate the shear rate of the soft material.

[0058] Preferably, the central gripping bars 18b also have at least one anchoring notch 36 in the flexible material on each of their two lateral faces 34. Advantageously, these anchoring notches 36 have a rounded profile.

[0059] Similarly, the two lateral gripping bars 18a each have, on their lateral face 38 opposite the lateral face 22a, at least one anchoring notch 40 in the flexible material. Advantageously, these anchoring notches 40 also have a rounded profile.

[0060] According to another advantageous arrangement shown in Figure 1 A, at least some of the clamping pads 4 of the retaining device may further comprise a cylinder 42 whose rod 44 is aligned with a radial direction ZZ to the conduit 6a and at the end of which is mounted the casing 8 of the clamping pad.

Claims

Demands

1. Clamping pad (4-1 to 4-6) for a friction-based holding device (2a-2c) for a tube (6a-6c) used for transporting fluids on the seabed or lakebed, comprising a steel casing (8) in which a cavity (10) is formed, having a bottom (12) and two opposing lateral edges (14) intended to extend along a longitudinal axis (XX) of the tube, the cavity being filled with a flexible polymer material (16) in which are housed a plurality of gripping bars (18a, 18b) distributed between the two lateral edges of the cavity, extending along the longitudinal axis of the tube and each having a contact face intended to come into contact with an external surface of the tube, characterized in that: - the lateral gripping bars (18a) that are closest to the two lateral edges (14) of the cavity each have a different geometric shape from the other gripping bars (18b) and each have a lateral face (22a) opposite a lateral edge (14) of the cavity which has a rounded profile conforming to the profile of the corresponding lateral edge of the cavity and which is in sliding contact with it in order to laterally confine the flexible material in the cavity, and - the skate further includes means for confining the flexible material (16) in the cavity (10) between the gripping bars at their respective contact face.

2. Pad (4-1; 4-2) according to claim 1, comprising semi-rigid polymer plugs (24) disposed between the gripping bars (18a, 18b) at their respective contact face in order to confine the flexible material (16) in the cavity (10) between the gripping bars.

3. Pad (4-3) according to claim 1, comprising strips of rolled steel (26) embedded in the soft material (16) between the gripping bars (18a, 18b) at their respective contact face in order to confine the soft material in the cavity between the gripping bars.

4. Pad (4-4) according to claim 1, the gripping bars (18a, 18b) are in contact with each other at their respective contact face in order to confine the soft material in the cavity between the gripping bars.

5. Pad (4-5) according to claim 1, comprising flexible metal bellows (28) welded between the gripping bars (18a, 18b) at their respective contact face in order to confine the flexible material in the cavity between the gripping bars.

6. Pad (4-6) according to claim 1, in which the flexible material (16) is confined in the cavity (10) by a more rigid polymer material (30) which completely encloses the flexible material.

7. Skate according to any one of claims 1 to 6, wherein the central gripping bars (18b) located between the lateral gripping bars (18a) each have a portion embedded in the flexible material (16) which is rounded.

8. Skate according to any one of claims 1 to 7, wherein the gripping bars (18a, 18b) have, at their opposite lateral faces, at least one anchoring notch (36, 40) in the flexible material.

9. Skate according to any one of claims 1 to 8, wherein the lateral edges (14) of the cavity (10) are covered with a layer (32) of thermoplastic polymer.

10. A skid according to any one of claims 1 to 9, further comprising a cylinder (42) having a rod (44) intended to be arranged in a radial direction (ZZ) to the tube and at the end of which the casing (8) is mounted.

11. A pad according to any one of claims 1 to 10, wherein the contact face of the gripping bars (18a, 18b) which is intended to come into contact with the outer surface of the tube has grooves, knurling or machining to improve the grip of the sliding surface of the pipe.

12. A device for retaining a tube by friction, comprising two clamping pads (4) according to any one of claims 1 to 10 which are arranged opposite each other with respect to the longitudinal axis (X-X) of the tube.

13. A device for holding a tube by friction, comprising three, four, six or eight clamping pads (4) according to any one of claims 1 to 10, said pads being spaced angularly apart from each other in a regular manner.

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