GB2519943A

GB2519943A - Apparatus and method

Info

Publication number: GB2519943A
Application number: GB1317037.8A
Authority: GB
Inventors: Richard James Parkinson; Richard Samuel Kelway Argall; Russell Henman
Original assignee: MOJO MARITIME Ltd
Current assignee: MOJO MARITIME Ltd
Priority date: 2013-09-25
Filing date: 2013-09-25
Publication date: 2015-05-13
Also published as: FR3011135A1; GB201317037D0

Abstract

An apparatus for connecting devices and cables between a marine energy converter and subsea foundation comprises a stab plate connection 10A, 12A. One of the stab plates 10A is moved by a connection-establishing part which includes first and second articulated sections 14, 16 which are independently articulated / pivoted to align the stab plates 10A, 12A. A movable element or linear actuator 20 may be used to move the parts axially into connection. The apparatus may also comprise locking cams (28 figure 11) for locking the two parts together which are actuated by the linear actuator 20. These arrangements allow connections to be aligned and made up underwater by a separate connection establishing apparatus, which is not required to remain in place.

Description

APPARATUS AND METHOD

In the Marine Renewable Energy (MRE) industry the majority of technical solutions being developed call for subsea cables to transfer the generated electricity from the device to shore, and control signals from shore back to the device. Generally, the s cables should not require on-going maintenance and ideally would be left alone on/under the seabed, to minimise the risk of damage. However, the energy-converting devices, such as turbine devices, will need to be installed, retrieved and replaced potentially multiples of times during a project. Thus, there exists an important physical interface between the different subsea components.

Presently, the connection and disconnection between devices and cables involves one of two potential solutions; a so-called "dry-mate" connection, or a so-called "wet-mate" connection. Both solutions involve the physical engagement of two parts of a connection interface; "dry mate" connections being engaged/disengaged out of the water, whilst "wet-mate" connections can be engaged/disengaged underwater.

is "Wet-mate" solutions therefore carry significant advantages, because the marine operations required are fewer, quicker, less costly and safer.

There are currently three options for actuating a wet-mate connection system; divers, Remotely Operated Vehicles (ROVs), or a remotely operated stab-plate. The costs and risks for operations involving divers and ROVs are extremely high, primarily because the operational windows for such activities are so short, limited to the durations of slack tides. Therefore, a remotely operated stab-plate is the preferable approach.

However, there are a number of technical challenges associated with remotely operating such a system in harsh environmental conditions, such as that of a tidal energy site; these are summarised as follows:- * the two parts of the system experience movement in six degrees of freedom whilst being subject to numerous and significant external forces which act independently on the different components, * different physical tolerances are required for different stages of the connection * there is a requirement for a redundant fail-safe locking mechanism that will maintain a connection even if a primary actuation system is removed.

According to a first aspect of the present invention, there is provided apparatus comprising a connection-establishing part connectable to a reference part wherein said connection-establishing part includes first and second articulated sections, the arrangement being such that the first and second articulated sections are independently articulated to align the connection-establishing part to the reference part for connection therewith.

According to a second aspect of the present invention, there is provided a method of connecting a connection-establishing part to a reference part comprising independently articulating first and second articulated sections of the connection-establishing part, so aligning the parts, and connecting the aligned parts.

Owing to these aspects, it is possible to achieve the required positional tolerances for a reliable connection to be made.

According to a third aspect of the present invention, there is provided apparatus for lockingly engaging one part to another part in an aquatic environment, the one part comprising a remotely operated element moveable relative to a locking device, wherein the element includes locking means arranged to engage said locking device upon movement of the element from an unlocked position to a locked position.

According to a fourth aspect of the present invention, there is provided a method of lockingly engaging one part to another part in an aquatic environment comprising remotely operating an element of the one part to move the element relative to a locking device, from an unlocked position to a locked position, locking means of the element engaging the locking device during the movement of the element.

Owing to these aspects, it is possible to maintain a sufficient mating force for the apparatus in the aquatic environment to be functional.

In order that the present invention can be clearly and completely disclosed, reference will now be made, by way of example only, to the accompanying drawings, in which:-Figures 1 to 4 show schematic views of different stages of an engagement process between a marine tidal turbine device and a fixed foundation in the seabed, Figure 5 is a perspective view of a subsea primary actuation system comprising a connection-establishing part and a reference part, Figure 6 is a sectional view of the system of Figure 5, Figures 7 is a detailed perspective view of an articulated section of the connection-establishing part of Figures 5 and 6, Figures 8 to 10 are schematic views of the system of Figures 5 to 7, S Figures ha to lit show diagrammatically the stages of a locking process, and Figures 1 2a to 1 2g are similar to Figures ii a to ii f, but show diagrammatically the stages of an unlocking process.

Referring to Figures 1 to 4, the general procedure of making a connection between a tidal turbine device 2 or similar device and a fixed foundation 4 in the seabed SB is shown in different stages. In Figure 1, the device 2 is lowered from a vessel or platform (not shown) on the surface WL of the sea down through the water column through use of lifting equipment 3 mounted to the vessel or platform. Whilst being lowered, the device 2 has six degrees of freedom, namely forwards-and-backwards, side-to-side, up-and-down and rotation about the x, y and z axes in a three dimensional space. In addition, there are a plurality of external forces acting upon the device 2, such as those created by waves, currents and vessel movements. The device 2 is shown as misaligned with the foundation 4 and, conventionally, the alignment would be made by way of divers, an ROV or cameras (or other suitable sensing devices) attached to the device 2. Figure 2 shows the connection between the device 2 and the foundation 4 having been established and Figure 3 represents the stage at which the relevant electrical and/or hydraulic connections 6 are complete to bring about the connection of a subsea cable 8 laid on the seabed SB.

Figure 4 represents the final stage when the lifting equipment is removed from the water column leaving the device 2 in mechanical and electrical/hydraulic connection with the foundation 4.

There is a need for a two-stage alignment process. The marine energy device 2 could weigh a few hundred tonnes, and may have to be lowered many tens of meters through the water column from the vessel or platform through extreme currents and waves. Initial lateral tolerances for connecting the device 2 with the foundation 4 can be in the order of +/-10 or 20mm. However the tolerances for mating the two parts for the electrical and/or hydraulic connections 6 can be at least one order of magnitude smaller; perhaps only +/-0.5mm. Similar differences in tolerances apply to the rotational alignments of the respective components.

Referring to Figures 5 and 6, a primary actuation system 9 comprises a connection-establishing part 10 connectable to a reference part 12. Advantageously, the part 10 includes an upper stab-plate 1OA mounted to the device 2 of Figures ito 4 and the part 12 includes a lower stab-plate i2A mounted to the foundation 4 and leading to the subsea cable 8. The part 10 includes first and second articulated sections 14 and 16 respectively in the form of first and second joints, a rigid frame 18 and a moveable element in the form of a linear actuator 20 mounted to the frame 18. The first articulated section 14 is located at an upper end region of the frame 18 and the second articulated section 16 is located at a lower end region of the frame 18 substantially directly beneath the first articulated section 14. As seen in Figure 6, the two outer frame members on respective opposite sides of the linear actuator 20 have the form of a rod-in-cylinder arrangement, respective compression springs 21 being is located between the ends of the cylinders and the articulated section 16.

The lower stab-plate 12A is, as already mentioned, fixed to the foundation 4 such that it cannot move. However the process of fixing the lower stab-plate 12A to the foundation 4 will be subject to its own positional tolerances, such that it may be offset both laterally and rotationally from its intended position. Therefore, all of the positional adjustments (both lateral and rotational) that are required to mate two sets of respective connector parts 22 must therefore be provided by a mechanism that moves the upper stab-plate bA.

The joint 14 is a flexible joint that connects the upper end of the linear actuator 20 with the frame 18, allowing two degrees of freedom (see Figure 7 and 8); such that the joint 14 allows the frame 18 to rotate in both vertical planes, such that the bottom of the frame 18 remains a fixed distance from the joint 14 but is able to move in a gentle arc around it (subject to the limitations of positional tolerance that depend on exact geometries).

The joint 16 is also a flexible joint that connects the bottom of the frame 18 with the upper stab-plate 1 OA, allowing three degrees of freedom (see Figure 9). The joint 16 thus permits rotation of the upper stab-plate 1 OA around all three orthogonal axes x, y and z (again, subject to the limitations of positional tolerance that depend on exact geometries).

Therefore, the combination of joints 14 and 16 permits five degrees of freedom for the upper stab-plate 1OA relative to the lower stab-plate 12A, which by definition means that a desired collinear alignment of upper and lower sets of connector parts 22 will be achievable. The remaining sixth degree of freedom, in a substantially vertical direction, which is required to realise the actual connection, is provided by the end of the linear actuator 20 moving downwardly. In this way, the entire system 9, including joint 14, the frame 18 and the joint 16 also move down, until the two sets of connector parts 22 are fully engaged. Figure 10 shows how the system 9 adapts to suit lateral and rotational discrepancies between the two stab-plates 1OA and 12A (potential misalignment in one vertical plane being illustrated; the system 9 will adapt to suit equivalent misalignment in the other orthogonal vertical plane as well, but for the sake of clarity this is not shown).

In order to keep the connector parts 22 engaged over a long period of time without requiring the on-going presence of the primary actuation system 9, a locking is mechanism is provided. Given the desire to avoid ROV or diver intervention, a locking mechanism activated and deactivated entirely by the primary actuation system 9 is preferable.

Referring to Figures ha to hf, the left-hand representation illustrates a side view of the top end region of the linear actuator 20 for each stage whilst the right hand representation illustrates a front view of the spatial relationship between the upper and lower stab-plates bA and 12A.

The moveable element or linear actuator 20 and its associated casing 23 (see Figures 6 and 7) form the central vertical member in the primary actuation system 9.

The casing 23 is preferably fixed to the device 2, and the linear actuator 20 slides substantially vertically within the casing 23; an actuation force being supplied by way of the linear actuator 20 being required to engage and disengage the connectors 22.

This is applied to the system through the interaction of the two components 20 and 23.

At the upper end region of the linear actuator 20, there is locking means shown as a pair of wedge portions 24 (see Figure 7) which are fixed to the linear actuator 20.

The wedge portions 24 are arranged protrude through a corresponding pair of substantially vertical slots 26 in the top of the frame 18 (see Figure 7). The slots 26 allow the linear actuator 20 to displace substantially vertically a small distance without moving the frame 18; once the wedges 24 are at the top of the slots 26 further upward displacement of the linear actuator 20 will push the frame 18 upwardly; conversely once the wedges 24 are at the bottom of the slots 26 further downward displacement of the linear actuator 20 will pull the frame 18 downwardly.

The locking mechanism further comprises a locking device; in the version shown in the Figures these are resiliently mounted locking cams 28 operationally associated with the linear actuator 20 and the wedge portions 24.

Figure ha shows the frame 18 in a raised position. The wedge portions 24 of the linear actuator 20 are positioned towards bottom region of the slots 26. The locking cams 28 are rotated inwardly owing to a biasing force from torsional springs (not shown). A notable clearance exists between one or more alignment pins 30 of the lower stub-plate 1 2A and corresponding guide cones 32 of the upper stub-plate 1 OA.

In Figure lib, actuation of the linear actuator 20 pulls the linear actuator 20 and wedge portions 24 downwardly and the interaction between the wedge portions 24 is with the bottom ends of the slots 26 pulls the frame 18 downwardly. The actuation of the linear actuator 20 can be of any suitable form, such as electrically or hydraulically. The outside edges of the wedge portions 24 make contact with the top ends of the locking cams 28. The clearance between the alignment pins 30 and the guide cones 32 still exists.

In Figure lic, the linear actuator 20 pulls wedge portions 24 and the frame 18 downwardly. Continuing interaction between the wedge portions 24 with the locking cams 28 forces the locking cams 28 to be displaced by rotating outwardly about a pivot against the bias of the torsional springs. At this stage, the clearance between the upper and lower stub-plates is reduced and the guide cones 32 partially cover the alignment pins 30.

In Figure lId, the linear actuator 20 pulls the wedge portions 24 and the frame 18 further downwardly. The wedge portions 24 pass below shoulders 34 of the locking cams 28, allowing the locking cams to rotate inwardly owing to the force from the torsional springs (not shown). At this stage, the guide cones 32 progress further onto the alignment pins 30 resulting in a small clearance between the connector parts 22.

In Figure lie, the linear actuator 20, pulls the wedge portions 24 and the frame 18 further downwardly such that the wedge portions 24 lose contact with the locking cams 28; the locking cams making contact with the top of the frame 18. The guide cones 32 progress even further onto the alignment pins 30 and an initial contact is made between connector parts 22.

Finally, in Figure 1 if, the linear actuator 20 pulls the wedge portions 24 and the frame 18 further downwardly. The top end region of the frame 18 passes below the shoulders 34 of the locking cams 28; the locking cams rotating inwardly owing to forces from the torsional springs (not shown), thus locking the frame 18 in position, the top end region of the frame 18 being of a form which closely receives the shoulders 34. The guide cones 32 are, at this stage, fully engaged with the alignment pins 30. Full engagement between connector pads 22 now exists. The wedge portions 24 are in close proximity or even abutting the ends of the locking cams 28 and the compression springs 21 in this condition are in a compressed state.

When the time comes for the replacement of or the maintenance of the device 2, then disengagement of the locking mechanism is required, and this process is shown in Figures 12a to 12g.

is In Figure 12a, the frame 18 is shown locked in its lower position. The wedge portions 24 are positioned at the bottom end of the slots 26. The locking cams 28 are rotated inwardly owing to the force from the torsional springs (not shown), with the shoulders 34 in contact with the top end region of the frame 18. The connectors 22 are fully engaged and the compression springs 21 are compressed.

In Figure 12b, the linear actuator 20 moves upwardly, causing the wedge portions 24 to move upwardly in the slots 26. The interaction between the outside edges of the wedge portions 24 and the inside surfaces of the locking cams 28 causes the locking cams 28 to rotate outwardly. The top end of the frame 18 remains in contact with the shoulders 34 of the locking cams 28, ensuring that the frame 18 does not move. The connector pads 22 remain fully engaged and the compression springs 21 remain compressed.

Figure 12c shows that the linear actuator 20 causes the wedge portions 24 to move upwardly in the slots 26. As the wedge portions move upwardly, the locking cams 28 rotate outwardly until the shoulders 34 are no longer in contact with top end of the frame 18. At this point, the frame 18 becomes unlocked and is free to move upwardly. The compression springs 21 push the frame 18 upwardly and the connector parts 22 remain engaged, though the mating force previously keeping them engaged is removed.

In Figure 12d, it can be seen that the linear actuator 20 causes the wedge portions 24 to make contact with the top end of the slots 26, thus pushing the frame 18 upwardly. The connector parts 22 disconnect and the guide cones 32 begin to slide upwardly of the alignment pins 30.

Figure 12e shows that the linear actuator 20 pushes the wedge portions 24 and the frame 18 upwardly until the wedge portions make contact with the shoulders 34 of the locking cams 28. The interaction of the wedge portions 24 and the locking cams 28 cause the locking cams 28 to rotate outwardly. A clearance is thus created between the connector pads 22 and the guide cones 32 continue to slide upwardly of the alignment pins 30.

Referring to Figure 12f, the linear actuator 20 pushes the wedge portions 24 and the frame 18 further upwardly. Once the wedge portions 24 pass the shoulders 34 of the locking cams 28, the frame 18 is free to continue to move upwardly with the wedge portions passing between pivot points of the locking cams 28. The guide cones 32 is continue to slide upwardly of the alignment pins 30.

Finally, Figure 12g shows that the linear actuator 20 pushes the wedge portions 24 and the frame 18 upwardly such that the locking cams 28 make contact with a pair of stopping pins 36 to avoid contact with the linear actuator 20. A clearance is created between the guide cones 32 and the alignment pins 30.

The primary actuation system and the locking mechanism described has a number of advantages, namely:- * Stab-plates for engaging a number of wet-mate electrical, signal and fibre optic connectors * For remote subsea use in marine energy projects * Hydraulic or electric actuation * Two-stage connection: a course initial positional tolerance, with much finer positional tolerance for final alignment and connection * To be operated vertically or horizontally * Six degrees of freedom for positional adjustment: lateral along and rotational around x,yandzaxes * To lock the two stab-plates together automatically when connectors are mated * Ability to disengage connection Mating force maintained, when primary actuation system is remove, as a fail-safe "redundancy" measure.

Even in the event of a situation such as failure of the primary actuation system and/or the locking mechanism after the system has been activated and a diver or s ROV is required, the present invention significantly reduces the mount of time for which a diver or ROV is required, and is thus a far more cost-effective way of making subsea connections.

Claims

CLAIMS1. Apparatus comprising a connection-establishing part connectable to a reference part wherein said connection-establishing part includes first and second articulated sections, the arrangement being such that the first and second articulated sections are articulated to align the connection-establishing part to the reference part for connection therewith.
2. A method of connecting a connection-establishing part to a reference part comprising articulating first and second articulated sections of the connection-establishing part, so aligning the parts, and connecting the aligned parts.
3. Apparatus for lockingly engaging one part to another part in an aquatic environment, the one part comprising a remotely operated element moveable relative to a locking device, wherein the element includes locking means arranged to engage said locking device upon movement of the element from an unlocked position to a locked position.is 4. A method of lockingly engaging one part to another part in an aquatic environment comprising remotely operating an element of the one part to move the element relative to a locking device, from an unlocked position to a locked position, locking means of the element engaging the locking device during the movement of the element.Amendments to the claims have been filed as follows:CLAIMS1. Apparatus comprising a connection-establishing part connectable to a reference part wherein said connection-establishing part includes first and second articulated sections, the arrangement being such that the first and second articulated sections are articulated to align the connection-establishing part to the reference part for connection therewith.2. Apparatus according to claim 1, wherein the connection-establishing part includes an upper stab-plate mounted to a marine energy device.3. Apparatus according to claim 1 or 2, wherein the reference part includes a lower stab-plate mounted to a fixed foundation.
4. Apparatus according to any preceding claim, wherein the first and second articulated sections are in the form of first and second joints.
5. Apparatus according to claim 4, wherein the connection-establishing part further comprises a rigid frame and a moveable element in the form of a linear is actuator mounted to the frame.
6. Apparatus according to claim 5, wherein the first articulated section is located at an upper end region of the frame and the second articulated section is 0 located at a lower end region of the frame substantially directly beneath the first articulated section.
7. Apparatus according to claim 5 or 6, wherein two outer members of the frame on respective opposite sides of the linear actuator have the form of a rod-in-cylinder arrangement, respective compression springs being located between the ends of the cylinders and the second articulated section.
8. Apparatus according to any one of claims 5 to 7, wherein the first articulated section is a flexible joint that connects an upper end of the linear actuator with the frame.
9. Apparatus according to any one of claims 5 to 8, wherein the second articulated section is a flexible joint that connects the bottom of the frame with the upper stab-plate.
10. Apparatus according to any preceding claim, and further comprising a locking mechanism.
11. Apparatus according to claim 10 as appended to any one of claims 5 to 9, wherein said locking mechanism includes locking means arranged to engage a locking device upon movement of the linear actuator from an unlocked position to a locked position.
12. A method of connecting a connection-establishing part to a reference part comprising articulating first and second articulated sections of the connection-establishing part, so aligning the parts, and connecting the aligned parts.
13. A method according to claim 12, wherein the first and second articulated sections are in the form of first and second joints.
14. A method according to claim 13, wherein the connection-establishing part further comprises a rigid frame and a moveable element in the form of a linear actuator mounted to the frame.
15. A method according to claim 14, wherein the first articulated section is located at an upper end region of the frame and the second articulated section is located at a lower end region of the frame substantially directly beneath the first articulated section.
16. A method according to claim 14 or 15, wherein two outer members of the is frame on respective opposite sides of the linear actuator have the form of a rod-in-cylinder arrangement, respective compression springs being located between the ends of the cylinders and the second articulated section.0')
17. A method according to any one of claims 14 to 16, wherein the first articulated section is a flexible joint connecting an upper end of the linear actuator with theframe.
18. A method according to any one of claims 14 to 17, wherein the second articulated section is a flexible joint connecting the bottom of the frame with the upper stab-plate.
19. A method according to any one of claims 14 to 18, and further comprising lockingly engaging the connection-establishing part to the reference part, the engaging comprising remotely operating the moveable element to move the element relative to a locking device, from an unlocked position to a locked position, locking means of the element engaging the locking device during the movement of the element.
20. Apparatus for lockingly engaging one part to another part in an aquatic environment, the one part comprising a remotely operated element moveable relative to a locking device, wherein the element includes locking means arranged to engage said locking device upon movement of the element from an unlocked position to a locked position.
21. Apparatus according to claim 20, wherein the element is a linear actuator mounted to a frame.
22. Apparatus according to claim 20 or 21, wherein at an upper end region of the element there is locking means.
23. Apparatus according to claim 22, wherein the locking means are a pair of wedge portions fixed to the element.
24. Apparatus according to claim 23, wherein the wedge portions are arranged to protrude through a corresponding pair of substantially vertical slots in a top region of the frame, the slots arranged to allow the element to displace substantially vertically a small distance without moving the frame.
25. Apparatus according to any one of claims 20 to 24, wherein the locking device are resiliently mounted locking cams operationally associated with the element and the wedge portions.
26. A method of lockingly engaging one part to another part in an aquatic is environment comprising remotely operating an element of the one part to move the element relative to a locking device, from an unlocked position to a locked position, locking means of the element engaging the locking device 0') during the movement of the element.
27. A method according to claim 26, wherein at an upper end region of the element there is locking means.
28. A method according to claim 27, wherein the locking means are a pair of wedge portions fixed to the element.
29. A method according to claim 28, wherein the wedge portions are arranged to protrude through a corresponding pair of substantially vertical slots in a top region of of the frame, the slots arranged to allow the element to displace substantially vertically a small distance without moving the frame.
30. A method according to claim 28 or 29, wherein once the wedges are at the top of the slots further upward displacement of the element will push the frame upwardly; conversely once the wedges are at the bottom of the slots further downward displacement of the element will pull the frame downwardly.
31. A method according to any one of claims 28 to 30, wherein the locking device are resiliently mounted locking cams operationally associated with the element and the wedge portions.
32. A method according to claim 31, wherein when the frame is in a raised position, the wedge portions are positioned towards a bottom region of the slots and wherein the locking cams are rotated inwardly owing to a biasing force from torsional springs.
33. A method according to claim 32, wherein actuation of the element pulls the s element and wedge portions downwardly and interaction between the wedge portions and the bottom ends of the slots pulls the frame downwardly, the outside edges of the wedge portions making contact with the top ends of the locking cams.
34. A method according to claim 33, wherein continuing interaction between the wedge portions and the locking cams forces the locking cams to be displaced by rotating outwardly about a pivot against the bias of the torsional springs.
35. A method according to claim 34, wherein the element pulls the wedge portions and the frame further downwardly, the wedge portions passing below shoulders of the locking cams, thus allowing the locking cams to rotate is inwardly owing to the force from the torsional springs.
36. A method according to claim 35, wherein the element pulls the wedge portions and the frame further downwardly such that the wedge portions lose contact 0') with the locking cams, the locking cams making contact with the top of the frame.
37. A method according to claim 36, the element pulls the wedge portions and the frame further downwardly, the top end region of the frame passing below the shoulders of the locking cams, the locking cams rotating inwardly owing to forces from the torsional springs, thus locking the frame in position, the top end region of the frame being of a form which closely receives the shoulders.