Clamp for gripping a conduit in a body of water with adaptable load distribution

Abstract

A clamp for gripping a conduit in a body of water has a support frame (9) extending along a longitudinal axis (A) and around the longitudinal axis (A); a plurality of clamping assemblies (10), which are supported by the support frame (9) in series along the longitudinal axis (A), are configured to selectively grip and release a section of the conduit (2) and each comprises at least two clamping units (11,12) facing and opposite each other, each clamping unit (11, 12) comprising a friction pad (13) configured to be placed in contact with the conduit (2); and a load distribution panel (14), which is coupled to the friction pad (13) and has an elastic layer (23) and at least one rigid layer (24, 25) provided with a protruding element (26) extending over the rigid layer (24, 25).

Description

[0001] "CLAMP FOR GRIPPING A CONDUIT IN A BODY OF WATER WITH ADAPTABLE LOAD DISTRIBUTION"

[0002] Cross-Reference to Related Applications This Patent Application claims priority from Italian Patent Application No . 102025000008670 filed on April 17, 2025, the entire disclosure of which is incorporated herein by reference .

[0003] Technical Sector

[0004] This invention relates to a clamp for gripping a conduit in a body of water .

[0005] Although this description will sometimes specifically refer to pipelines laid on the bed of a body of water, for the purposes of this invention, the term "conduit" includes any section of carbon steel pipe, of any length, and is not limited to pipelines laid on the bed of a body of water and intended for the transport of hydrocarbons, such as gas or oil pipelines or pipelines for the transport of resources or lines for energy transport .

[0006] State of the Art

[0007] As is well known, the laying of conduits on the bed of a body of water is achieved by alternating sequences of assembling carbon steel pipe sections and launching the assembled pipe sections . New sections of pipe are gradually added to the existing conduit to form a seamless conduit of increasing length.

[0008] Typically, the pipe sections have a unit length, usually 12 metres, and relatively large diameters of between 0.2 and 1.5 metres . Each pipe section comprises a steel cylinder and a polymer coating, the function of which is to protect the steel cylinder from corrosion and heat loss .As is well known, the assembly and launching of conduits is carried out on board pipe-laying vessels according to two methods, referred to as "S" and "J" launching respectively. These methods differ fundamentally in the angle at which the conduit exits the pipe-laying vessel, which gives the section of conduit suspended between the pipe-laying vessel and the bed of the body of water a distinctive shape . Under the same conditions of water body bed depth and conduit, the shape of the "S" launching method results in greater axial tension and thus greater rigidity of the vessel and conduit system than the shape of the "J" launching method.

[0009] The two launching methods also differ in the type of gripping devices used to grip the conduit during the launching phase . The "S" launching method uses rolling friction devices, such as vertical presses, commonly referred to as tensioners, which operate on a pair of rotating tracks on the conduit, while the "J" launching method preferably uses static friction clamping devices, such as radial presses, which are commonly referred to as "clamps" and are equipped with gripping pads .

[0010] In particular, the "J" launching method uses a pair of clamping devices consisting of a first fixed clamping device ("Hang Off Clamp", HOC) and a second movable clamping device ("Travelling Clamp", TRAC) . The conduit is launched by an alternating gripping and releasing (push-pull) action of these clamping devices on the conduit, coordinated with an alternating back-and-forth movement of the movable clamping device .

[0011] Both the known launching methods identified above involve coordinating the launching of the conduit with the advancing movement of the pipe-laying vessel .At present, ever-increasing depths of the water body and increasing conduit diameters generally lead to extreme situations in terms of suspended conduit pull never before experienced in the field. Consequently, to avoid the risk of conduit loss, the known clamping devices must apply a greater, but at the same time uniform, gripping load on the conduit in order not to damage the conduit ' s outer protective coating .

[0012] However, the need to achieve a uniform distribution of the gripping load on the conduit is hampered by numerous factors that lead to uneven loading and hyperstatic conditions . In particular, these factors include the deformability of the conduit along its longitudinal axis and geometric factors in cases where the geometry of the pipe sections is not perfectly circular or where there are misalignments between the axis of the conduit and the axis of the clamping device .

[0013] With particular reference to clamping devices for gripping conduits, it is commonly known to use asymmetrically actuated clamps comprising a plurality of j aw assemblies, whereby each aw assembly comprises at least two pairs of j aws, which face and are opposite each other, with a respective friction pad configured to be placed in contact with the underwater conduit . One of the two j aws is fixed to the support frame, and the other of the two j aws is pushed against the conduit by a hydraulic piston to cyclically clamp the conduit between the two j aws .

[0014] Typically, in asymmetrically actuated clamps, since one of the two j aws, which face and are opposite each other, is fixed to the support frame, said j aw must be mounted precisely in a certain position on the support frame in orderto adapt the j aw assembly to the theoretical diameter of the conduit to be launched.

[0015] However, due to tolerances or manufacturing defects, the conduit diameter may vary from the theoretical dimensions that were used to determine the assembly position of the fixed j aw. This circumstance results in an uneven and unpredictable distribution of the grip of the j aw assembly on the conduit with consequent issues that may result in the risk of conduit loss, especially in the case where each j aw assembly comprises four j aws, two of which are fixed and two movable .

[0016] In addition, if the operations carried out by the laying vessel in the body of water involve a change in the diametric dimensions of the conduit to be launched, the fixed j aws must be replaced or repositioned. Such operations cause launching operations to be stopped and entail safety risks for the personnel involved.

[0017] Subject of the Patent

[0018] One purpose of this invention is to provide a clamp for gripping a conduit in a body of water, which reduces the drawbacks of the prior art .

[0019] In particular, one purpose of this invention is to uniformly distribute applied pressure both around the annular gripping section of the conduit and along the axial direction of the conduit, thereby decreasing unevenness .

[0020] In accordance with this invention, a clamp for gripping a conduit in a body of water is provided, the clamp comprising :

[0021] - a support frame extending along a longitudinal axis and around the longitudinal axis;a plurality of clamping assemblies, which are supported by the support frame in series along the longitudinal axis, are configured to selectively grip and release a section of the conduit that extends along the longitudinal axis, and each comprises at least two clamping units, which face and are opposite each other,

[0022] each clamping unit comprising a friction pad configured to be placed in contact with the conduit when, in use, the respective clamping assembly grips the conduit; and a load distribution panel, which is coupled to the friction pad and has an elastic layer and at least one rigid layer provided with a protruding element extending over the rigid layer for a first length in a first direction and for a second length in a second direction essentially perpendicular to the first direction, wherein the first length is essentially equal to the second length.

[0023] In practice, in addition to distributing the load on the friction pads in a direction that is essentially parallel to the longitudinal axis, the load distribution panel allows the load to be distributed circumferentially around the conduit in such a way that the friction pad adheres uniformly to the conduit even if the clamping units are not precisely centred with respect to the conduit .

[0024] In other words, the elastic layer in combination with the shape of the protruding element allows for a deformation of the load distribution panel resulting in a displacement of the friction pad in a circumferential direction around the conduit in order to compensate for any misalignment of the conduit with respect to the clamping assembly, resulting in an even thrust of the friction pad against the conduit .Thus, in asymmetrically actuated clamps, the need to replace or reposition friction pads during launching operations of the conduit into the body of water can be avoided, resulting in time and cost savings and improved safety conditions for launch operators .

[0025] In particular, the protruding element has an essentially circular shape and is arranged in a central portion of the load distribution panel .

[0026] In this way, the circumferential load transmitted by each friction pad on the conduit can be optimally distributed .

[0027] In particular, the friction pad has a concave face configured to be arranged in contact with the conduit and a flat face configured to be coupled to the load distribution panel .

[0028] In this way, an optimal grip of each clamping unit on the conduit can be ensured.

[0029] In particular, the load distribution panel comprises two rigid layers, between which the elastic layer is interposed to form a multilayer panel .

[0030] In practice, the load distribution panel is composed of a series of layers with different rigidities to ensure the necessary elasticity of the respective clamping unit both in the longitudinal axis direction and in a circumferential direction with respect to the conduit .

[0031] In particular, at least one of the clamping units of one of the clamping assemblies comprises an actuator configured to control a position of the respective friction pad with respect to the conduit and / or to control a thrust of the respective friction pad against the conduit; the loaddistribution panel being interposed between the respective actuator and the respective friction pad.

[0032] In this way, at least one of the clamping units can be cyclically pushed against the conduit to selectively clamp the conduit between the two clamping units, which face and are opposite to each other .

[0033] In particular, each clamping unit comprises a rigid connecting element interposed between the load distribution panel and the frame or between the load distribution panel and the actuator to couple the clamping unit to the frame or actuator .

[0034] Brief Description of the Figures

[0035] Further features and advantages of the present invention will be apparent from the following description of a non-limiting embodiment thereof, with reference to the Figures of the accompanying drawings, wherein:

[0036] - Figure 1 is a side view, with parts removed for clarity, of an underwater conduit laying vessel comprising a clamp for gripping a conduit in accordance with this invention;

[0037] - Figure 2 is a cross section, with parts removed for clarity, of the clamp in Figure 1.

[0038] - Figure 3 is another cross section, with parts removed for clarity, of the clamp in Figure 1.

[0039] - Figure 4 is an exploded perspective view, with parts removed for clarity, of a clamping unit of the clamp in Figure 1 ; and

[0040] - Figure 5 is a front view, with parts removed for clarity, of a detail of the clamping unit in Figure 4.

[0041] Detailed Description of the Figures

[0042] With reference to Figure 1, the reference number 1 is used to indicate, as a whole, a laying vessel designed tolay a conduit 2 on the bed of a body of water (SL indicates the level of the body of water) .

[0043] In particular, the conduit 2 may comprise, for example, a pipe or a cable or an umbilical . In the case described and illustrated herein, which does not limit this invention, the conduit 2 consists of a pipeline made up of pipe sections (not illustrated in the accompanying Figures) joined to each other .

[0044] The laying vessel 1 comprises a semi-submersible vessel 3, and a launching tower 4, which extends along a longitudinal axis A, is articulately mounted to the semisubmersible vessel 3 and is designed for a "J" launch. Although, the launching tower 4 is shown in a vertical position, the launching tower 4 can be inclined at an angle of up to 30° to the vertical position when launching the conduit 2 .

[0045] The launching tower 4 comprises an upper section 5, in which the assembly operations of the conduit 2 are carried out; an intermediate section 6, in which a track tensioner, not illustrated in the attached figures, is arranged; and a lower section 7, in which a clamp 8 is arranged to grip the conduit 2 .

[0046] It is understood that, in accordance with one embodiment not shown in the attached figures, the semi-submersible vessel 3 may comprise a launching tower 4 designed for an "S" launch.

[0047] With reference to Figure 2, the clamp 8 is arranged around the conduit 2 being launched and is supported by the launching tower 4 .

[0048] The clamp 8 comprises a support frame 9 extending along the longitudinal axis A and around the longitudinal axis A;and a plurality of clamping assemblies 10, which are supported by the support frame 9 in series along the longitudinal axis A, are configured to selectively grip and release a section of the conduit 2 that extends along the longitudinal axis A, and each comprises at least two clamping units 11, 12 facing and opposite each other .

[0049] In particular, the support frame 9 extends around the conduit 2 and is fixed to the launching tower 4 or, according to a variant not illustrated, is supported by the launching tower 4 in a sliding manner in the direction defined by the longitudinal axis A by means of a known mechanism not illustrated in the attached figures .

[0050] In the case described and illustrated herein, which does not limit this invention, the clamp 8 comprises six clamping assemblies 10 arranged in series along the longitudinal axis A. It is understood that, in accordance with additional embodiments of this invention not shown in the appended figures, the number of clamping assemblies 10 arranged in series may be different to six .

[0051] With reference to Figure 3, the clamping units 11, 12 of each clamping assembly 10 are evenly distributed around the longitudinal axis A and, in use, around the conduit 2.

[0052] In general, each clamping assembly 10 comprises at least two clamping units 11, 12, which face and are opposite each other, for exchanging a clamping force F with the conduit 2. In accordance with the embodiment described and illustrated herein, which does not limit this invention, each clamping assembly 10 comprises four clamping units 11, 12, which face and are opposite each other, in pairs . It is understood that, in accordance with additional embodiments of this invention not shown in the accompanying figures, each clamping assembly10 may comprise a number other than four of clamping units 11, 12 facing each other in pairs .

[0053] In accordance with this invention, each clamping unit 11, 12 comprises a friction pad 13 configured to be arranged in contact with the conduit 2 when, in use, the respective clamping assembly 10 grips the conduit 2 ; and a load distribution panel 14 coupled to the friction pad 13.

[0054] In particular, each clamping unit 11 comprises an actuator 15 configured to control a position of the respective friction pad 13 with respect to the conduit 2 and / or to control a thrust of the respective friction pad 13 against the conduit 2 .

[0055] More specifically, each actuator 15 comprises a hydraulic cylinder 16 and a piston 17 engaged so as to slide in the hydraulic cylinder 16. In other words, the piston 17 is configured to move the friction pad 13 along a direction essentially perpendicular to the longitudinal axis A so as to selectively push the friction pad 13 against the conduit 2 or move the friction pad 13 away from the conduit 2.

[0056] In particular, the load distribution panel 14 of each clamping unit 11 is interposed between the respective actuator 15 and the respective friction pad 13.

[0057] More specifically, each clamping unit 11 comprises a rigid connecting element 18, which is interposed between the load distribution panel 14 and the respective actuator 15 and mechanically connects the load distribution panel 14 and the actuator 15.

[0058] In the non-limiting embodiment of this invention described and illustrated herein, each clamping unit 12 is mounted in a fixed position on the support frame 9. In particular, each clamping unit 12 is fixed on the supportframe 9 in a diametrically opposite position to the respective clamping unit 11.

[0059] More specifically, the rigid connecting element 18 of each clamping unit 12 is interposed between the respective load distribution panel 14 and the support frame 9 and mechanically connects the load distribution panel 14 to the support frame 9.

[0060] In particular, the support frame 9 comprises a main body 19 and two movable arms 20, each of which is hinged to the main body 19 so that it pivots around a respective hinge 21 that allows rotation of the respective movable arm 20 around a respective axis essentially parallel with respect to the longitudinal axis A.

[0061] Operationally speaking, the movable arms 20 are hinged to the main body 19 so as to pivot between a closed position, in which the movable arms 20 are arranged around the conduit 2, and an open position, in which the movable arms 20 are disengaged from the conduit 2.

[0062] In particular, the support frame 9 comprises a pair of actuators 22, each of which is associated with a respective movable arm 20 and is configured to control the rotation of the respective movable arm 20 around the respective hinge 21. More specifically, each actuator 22 comprises a respective hydraulic cylinder acting between the main body 19 and the respective movable arm 20.

[0063] In the non-limiting embodiment of this invention described and illustrated herein, the clamping units 11 are coupled to the main body 19 and each clamping unit 12 is mounted in a fixed position on the movable arm 20.With reference to Figure 4, each load distribution panel 14 has an elastic layer 23 and at least one rigid layer 24, 25 provided with a protruding element 26.

[0064] In particular, the load distribution panel 14 comprises two rigid layers 24, 25, between which the elastic layer 23 is interposed so as to form a multilayer panel . In other words, the load distribution panel 14 has a so-called "sandwich structure", in which the elastic layer 23 is sandwiched between the two rigid layers 24, 25 and is less rigid than each rigid layer 24, 25.

[0065] In addition, the rigid layer 24 comprises at least one coupling protrusion 27, which is configured to couple with the friction pad 13 and is essentially circular in shape .

[0066] In particular, the friction pad 13 has a concave face 28 configured to be arranged in contact with the conduit 2 and a flat face 29 configured to be coupled to the load distribution panel 14.

[0067] More specifically, the flat face 29 has a first recess, not visible in the accompanying figures, shaped so as to house the protruding element 26 of the rigid layer 24, and a second recess, not visible in the accompanying figures, shaped so as to house the coupling protrusion 27 of the rigid layer 24 .

[0068] In accordance with one embodiment, the concave face 28 is made of a metal material and is provided with a series of notches to ensure adequate grip on the conduit 2 .

[0069] In accordance with one alternative embodiment, not shown in the accompanying figures, the concave face 28 is made of polymer material and performs the functions of adapting to the irregularities of the conduit 2 and evenlydistributing the compressive force along the entire contact surface between the friction pad 13 and the conduit 2.

[0070] In particular, the rigid connecting element 18 has an opening 30 shaped to accommodate the protruding element, not visible in the attached figures, of the rigid layer 25, and two openings 31, each of which is shaped to accommodate a respective coupling protrusion, not visible in the attached figures, of the rigid layer 25.

[0071] With reference to Figure 5, the protruding element 26 extends over the rigid layer 24 for a length LI in a direction DI and for a length L2 in a direction D2 essentially perpendicular to the direction DI, where the length LI is essentially equal to the length L2 .

[0072] In practice, the directions DI and D2 are perpendicular to the thickness of the load distribution panel 14.

[0073] In particular, the protruding element 26 is arranged in a central portion of the load distribution panel 14 and extends over the rigid layer 24 in an essentially symmetrical manner in the directions DI and D2 .

[0074] In the embodiment described and illustrated herein, which does not limit this invention, the protruding element 26 has an essentially circular shape .

[0075] In accordance with additional embodiments, not shown in the attached figures, the protruding element 26 may have a shape other than an essentially circular form. As an example, the protruding element 26 may have an essentially square shape or a regular polygon shape .

[0076] In particular, the diameter of the essentially circular shape of the protruding element 26 is greater than the diameter of the essentially circular shape of the coupling protrusion 27 .In addition, the load distribution panel 14 has a dimension, measured in a direction essentially parallel to the longitudinal axis A, that is greater than the other two dimensions . In other words, the dimension of the load distribution panel 14 measured in the direction DI is greater than the load distribution panel 14 measured in the direction D2 and is greater than the thickness of the load distribution panel 14 .

[0077] In use and with reference to Figure 3, the actuators 22 control the rotation of the respective movable arm 20 around the respective hinge 21 from the open position to the closed position, so that the movable arms 20 are arranged around the conduit 2 .

[0078] At this point, each actuator 15 pushes the respective clamping unit 11 against the conduit 2 with a given force to clamp the conduit 2 between the clamping unit 11 and the respective clamping unit 12, which faces and is opposite it .

[0079] In particular, when the conduit 2 is clamped between the clamping units 11 and 12, due to the essentially circular shape of the protruding element 26 (Figures 4 and 5) and the elasticity of the elastic layer 23 (Figures 4 and 5) , the load distribution panel 14 distributes the load circumferentially around the conduit 2 so as to create an even thrust of the friction pad 13 against the conduit 2 and to promote adhesion of the friction pad 13 to the conduit 2 even if the clamping units 11 and 12 are not precisely centred with respect to the conduit 2 .

[0080] Finally, it is clear that variations can be made to this invention in relation to the embodiment described without, however, departing from the scope of the following claims .

Claims

1. CLAIMS1 . A clamp for gripping a conduit in a body of water, the clamp ( 8 ) comprising :- a support frame ( 9 ) extending along a longitudinal axis (A) and around the longitudinal axis (A) ;- a plurality of clamping assemblies ( 10 ) , which are supported by the support frame ( 9 ) in series along the longitudinal axis (A) , are configured to selectively grip and release a section of the conduit ( 2 ) that extends along the longitudinal axis (A) , and each comprises at least two clamping units ( 11 , 12 ) facing and opposite each other, each clamping unit ( 11 , 12 ) comprising a friction pad ( 13 ) configured to be placed in contact with the conduit ( 2 ) when, in use , the respective clamping assembly ( 10 ) grips the conduit ( 2 ) ; and a load distribution panel ( 14 ) , which is coupled to the friction pad ( 13 ) and has an elastic layer ( 23 ) and at least one rigid layer ( 24 , 25 ) provided with a protruding element ( 26 ) extending over the rigid layer ( 24 , 25 ) for a first length ( LI ) in a first direction ( DI ) and for a second length ( L2 ) in a second direction ( D2 ) substantially perpendicular to the first direction ( DI ) , wherein the first length ( LI ) is substantially equal to the second length ( L2 ) .2 . The clamp as claimed in Claim 1 , wherein the protruding element ( 26 ) has a substantially circular shape .3 . The clamp as claimed in Claim 1 or 2 , wherein the protruding element ( 26 ) is arranged in a central portion of the load distribution panel ( 14 ) .4 . The clamp as claimed in any one of the foregoing Claims , wherein the rigid layer ( 24 , 25 ) comprises a coupling protrusion ( 27 ) configured to couple with the friction pad5 . The clamp as claimed in Claim 4 , wherein said coupling protrusion ( 27 ) is substantially circular in shape .

6. The clamp as claimed in any one of the foregoing Claims , wherein the friction pad ( 13 ) has a concave face ( 28 ) configured to be arranged in contact with the conduit ( 2 ) and a flat face ( 29 ) configured to be coupled to the load distribution panel ( 14 ) .7 . The clamp as claimed in any one of the foregoing Claims , wherein the load distribution panel ( 14 ) has a dimension, measured in a direction substantially parallel to the longitudinal axis (A) , that is greater than the other two dimensions .8 . The clamp as claimed in any one of the foregoing Claims , wherein the load distribution panel ( 14 ) comprises two rigid layers ( 24 , 25 ) , between which the elastic layer ( 23 ) is interposed so as to form a multilayer panel .

9. The clamp as claimed in any one of the foregoing Claims , wherein at least one of the clamping units ( 11 , 12 ) of one of the clamping assemblies ( 10 ) comprises an actuator ( 15 ) configured to control a position of the respective friction pad ( 13 ) with respect to the conduit ( 2 ) and / or to control a thrust of the respective friction pad ( 13 ) against the conduit ( 2 ) ; the load distribution panel ( 14 ) being interposed between the respective actuator ( 15 ) and the respective friction pad ( 13 ) .10 . The clamp as claimed in Claim 9 , wherein each clamping unit ( 11 , 12 ) comprises a rigid connecting element ( 18 ) interposed between the load distribution panel ( 14 ) and the support frame ( 9 ) or between the load distribution panel ( 14 ) and the actuator ( 15 ) .

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