DEVICE, METHOD AND ASSEMBLY FOR PROVIDING AN ELONGATE ELEMENT IN A SEABED
20220381004 · 2022-12-01
Assignee
Inventors
- Jonathan Ralph Manchester (Stocksfield, Northumberland, GB)
- Michael John Watchorn (Stocksfield, Northumberland, GB)
Cpc classification
E02F5/14
FIXED CONSTRUCTIONS
International classification
E02F5/14
FIXED CONSTRUCTIONS
Abstract
A device for providing an elongated element in a seabed is disclosed. The device comprises a main body having trench forming means for forming a trench in a seabed, and a receiving section for receiving an elongated element. The main body is adapted to guide said elongated element, from said receiving section, into a trench formed by said trench forming means. The device further includes supporting means defining a contact surface for supporting said main body with respect to said seabed, wherein the receiving section is configured to receive the elongated element from a side substantially opposite to the contact surface along a loading path. The device further includes a drawbar connected to said main body. The drawbar is movable from a loading position to a towing position. In the towing position said device is towable in a trenching direction via a towing line connected to said drawbar. In the loading position the drawbar is spaced apart from the loading path to allow the elongated element to be loaded into the receiving section along the loading path.
Claims
1. A device for providing an elongated element in a seabed, the device comprising: a main body having: trench forming means for forming a trench in a seabed, and a receiving section for receiving an elongated element, wherein said main body is adapted to guide said elongated element, from said receiving section, into a trench formed by said trench forming means; supporting means defining a contact surface for supporting said main body with respect to said seabed, wherein the receiving section is configured to receive the elongated element from a side substantially opposite to the contact surface along a loading path; and a drawbar connected to said main body; wherein said drawbar is movable from a loading position to a towing position, wherein in the towing position said device is towable in a trenching direction via a towing line connected to said drawbar, wherein in the loading position the drawbar is spaced apart from the loading path to allow the elongated element to be loaded into the receiving section along the loading path.
2. The device of claim 1, further comprising actuator means for moving the drawbar from said loading position to said towing position.
3. The device of claim 1, wherein, in said towing position, said drawbar obstructs the loading path into said receiving section.
4. The device of claim 1, wherein the drawbar is movable between the loading position and the towing position.
5. The device of claim 1, wherein said drawbar comprises: a first engagement portion; and a second engagement portion spaced apart from said first engagement portion, each of said first and second engagement portions being suitable for engaging a towing line.
6. The device of claim 1, wherein said drawbar is movable from said loading position to said towing position around at least a first axis extending substantially perpendicular with respect to said contact surface.
7. The device of claim 1, wherein the drawbar is movable around a second axis that extends at least substantially perpendicular to said trenching direction and said first axis.
8. The device of claim 1, wherein the device includes a bell mouth located at an upstream end of the receiving section, the bell mouth being adapted to receive an elongate element therethrough, wherein the bell mouth is movable between a loading position and an operational position.
9. The device of claim 1, wherein the device includes a depressor extending from a downstream side of the main body, the depressor being arranged to guide the elongate element into a trench cut by the trench forming means, wherein the depressor is movable between a loading position and an operational position.
10. The device of claim 1, wherein said trench forming means comprise a trenching knife.
11. The device of claim 1, wherein said supporting means comprises at least one skid and at least one actuator to actuate said at least two skids with respect to said main body.
12. The device of claim 1, wherein said receiving section comprises a U-shaped frame, or a V-shaped frame for centralizing said elongate element.
13. The device of claim 1, said device further comprising guiding means for guiding an elongated element towards said receiving section.
14. The device of claim 1, said device further comprising grabbing means for grabbing an elongated element.
15. A method of providing an elongated element in a seabed, the method comprising the steps of: providing a device in accordance with any of the preceding claims on a seabed with said drawbar in the loading position; providing an elongated element; loading said elongated element into said receiving section from the side opposite to the contact surface, along the loading path; moving the drawbar into a towing position; towing the device across the seabed, such that a trench is formed with the trench forming means; and guiding the elongated element into the trench.
16. An assembly for providing an elongated element in a seabed, comprising: a device in accordance with claim 1; a vessel comprising a towing line, wherein said towing line is connected to the drawbar of said device.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0055] Embodiments will now be described by way of example only with reference to the accompanying drawings in which:
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[0072] In the drawings like reference numerals refer to like parts.
DETAILED DESCRIPTION OF THE INVENTION
[0073]
[0074] The plough 300 includes supporting means with a contact surface for supporting the main body 340 with respect to the seabed. In this example, the supporting means include at least one skid 302. In use the skids sit on the seabed (contacting the seabed via contact surfaces on an underside thereof) and support the main body 340 of the plough thereon. As shown in
[0075] In this example, the skids 302 are movable relative to the main body 340. In a first position the skids 302 are arranged such that the contact surface thereof is substantially co-planar with a lower surface of the trenching knife 306. Such a first position may be used, for example, when the plough 300 is initially lowered onto the sea bed. As the plough 300 is towed, the lowermost cutting blade 307.sub.1 begins to cut the trench. As the trench is cut, the skids 302 may be moved towards the main body 340 of the plough 300 (i.e. upwardly), wherein the depth of the resulting trench is increased (i.e. the distance between the contact surface of the skids 302 and the lowermost cutting blade 307.sub.1 or a lower portion of the trench forming means is increased). In a second position the skids 302 are proximal with the main body 340 of the plough 300. That is, in the second position, the distance between the contact surface of the skids 302 and the lowermost cutting blade 307.sub.1 is at a maximum, corresponding to the maximum trench depth.
[0076] In this example, the main body 340 includes at least one actuator to actuate the skids with respect to said main body 340. Any suitable actuator may be used, for example pneumatic or hydraulic actuators or the like. In this example, there is a separate actuator for each skid, however in other examples there may be a single actuator, or actuator system, configured to actuate the skids.
[0077] The main body 340 of the plough 300 further includes a receiving section 380 for receiving an elongate element 350 (or more specifically, for receiving a portion or section of an elongate element). In this example, the receiving section 380 extends along the longitudinal axis of the plough. That is, the axis of the plough that in use is generally aligned with the trenching direction T of the plough 300. The receiving section is configured to receive the elongate element such that the elongate element is in proximity of the plough also generally aligned with the longitudinal axis of the plough so that the elongate element is generally aligned with a trench cut by the trench forming means.
[0078] The receiving section 380 may be configured to receive any suitable elongate element, for example a cable, such as a power transmission cable or the like. It would be understood that the receiving section would be sized according to the type of elongate element received therein.
[0079] The receiving section is configured to receive the cable from a side of the plough 300 substantially opposite to the contact surface of the plough 300. That is, the plough 300 is configured to be top-loaded, with the cable lowered into the receiving section 380 from above (i.e. from the side of the plough opposite to the contact surface of the plough). In other words, the elongate element is loaded into the receiving section 380 along a loading path (represented by arrow 380 in
[0080] In this example, the receiving section includes an open channel to allow the cable to be loaded from above. In this example, the open channel includes a substantially U-shaped frame, however, in other examples the receiving section 380 may be shaped in any suitable configuration for receiving an elongate element.
[0081] The main body 340 of the plough 300 is adapted to guide the cable 350 from the receiving section, into the trench formed by the trench forming means 306. For example, once loaded, a section of the cable 350 is located into the receiving section. The section of the cable is connected to (i.e. integral with) an upstream section of the cable, which extends to the vessel from which both the cable and plough are deployed. As the plough 300 traverses the sea-bed, the plough 300 moves relative to the cable, and the upstream section passes through the plough and is deposited into the trench formed by the trench forming means, downstream of the plough. In this example, the plough 300 includes a bell mouth 324 located at an upstream end of the receiving section, the bell mouth being adapted to receive the upstream section of cable therethrough, before the cable passes through the receiving section.
[0082] The plough further includes a drawbar 308 connected to the main body 340. The drawbar 308 has a towing position, in which the plough 300 is towable in a trenching direction T via a towing line 309 connected to said drawbar 308. The towing line 309 may, for example, be connected to and towed by a vessel (for example the vessel from which the plough 300 is deployed).
[0083] In this example, the drawbar 308 includes a first engagement portion 318, and a second engagement portion 320 spaced apart from said first engagement portion (illustrated best in
[0084] In the towing position, the drawbar 308 extends across the receiving section. In particular, the drawbar 308 extends across the open channel of the receiving section. In this manner, in the towing position, the drawbar 308 prevents the receiving section from receiving a cable from above. That is, in the towing position the drawbar 308 obstructs the loading path into the receiving section (and hence prevents top-loading a cable therein).
[0085] The drawbar 308 has a loading position, in which the cable can be loaded into the receiving section along the loading path 380. In the loading position the drawbar 308 is spaced apart from the loading path 380. That is, in the loading position the drawbar 308 does not extend across the open channel of the receiving section in a manner that obstructs the cable being loaded into the receiving section. In other words, the position of the drawbar 308 when in the loading position allows the cable to be received in the loading path (as shown in
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[0087] The drawbar 308 is movable from the loading position to the towing position. In this example, the drawbar 308 is movable from said loading position to said towing position around a first axis 311 extending perpendicular to the lateral plane of the plough (that is, the plane of the plough that is parallel to the longitudinal axis of the plough and is (at least substantially) parallel to the seabed). The lateral plane can be defined by the support means, comprising skids 302, of the plough. When the plough 300 is arranged substantially horizontally on a seabed (i.e. in areas where the seabed is flat) this corresponds to the drawbar 308 being movable from said loading position to said towing position around a first axis 311 extending perpendicular with respect to the contact surface of the skids 302. That is, with the plough 300 arranged substantially horizontally on a seabed (i.e. the contact surface is arranged substantially horizontally), the drawbar 308 rotates around a substantially vertical axis 311, with the drawbar 308 moving in a horizontal plane.
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[0089] In the position illustrated in
[0090] In this example the movement of the drawbar 308 from the loading position to the towing position involves a rotation of the drawbar about more than one axis (that is, the transition from the loading position to the towing position is a two-stage movement). As shown in
[0091] In this example, the drawbar 308 is rotatably coupled to the main body of the plough 300 to allow the rotations around the two separate axis 311 and 321. In this example the drawbar 308 is rotatably coupled to the main body of the plough via at least one support frame or support assembly. In particular, in this example, the drawbar 308 is coupled or mounted to a first support frame 390, the first support frame 390 being rotatably coupled to the main body of the plough 300 to allow rotation of the drawbar 308 around the first axis 311.
[0092] In this example, the plough 300 includes actuator means (i.e. actuators) for moving the drawbar from the loading position to the towing position (that is, the actuating the rotation of the drawbar around the axes 311 and 321). Any suitable actuator may be used, for example pneumatic or hydraulic actuators or the like may be used.
[0093] In this example, the first support frame 390 is rotatably coupled to the main body of the plough 300 via a second support frame 392. Actuator 394 is configured to control the rotation of the first support frame 390 with respect to the second support frame 392 (i.e. around axis 311). As the actuator 394 actuates, the first support frame 390 rotates relative to the second support frame 392 (the second support frame 392 remaining in a fixed position) to move the drawbar 308 from the loading position to the launch and recovery position.
[0094] In this example, the second support frame 392 is itself rotatably mounted to the main body of the plough 300 to allow rotation of the drawbar 308 around the second axis 321. Actuator 396 is configured to control the rotation of the second support frame 392 with respect to the main body of the plough 300 (i.e. around the second axis 321). As the actuator 396 actuates, the first and second support frames 390, 392 rotate relative to the main body of the plough 300 to move the drawbar 308 from the launch and recovery position to the towing position. In this example, the drawbar 308 is pivotally mounted. That is, as shown in
[0095] Any suitable actuator may be used for actuators 394 and 396, for example pneumatic, hydraulic or electric actuators or the like may be used (in particular hydraulic or electric actuators due to the ambient pressure).
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[0097] In some examples, the plough 300 may be provided initially with the drawbar 308 in the loading position (for example the plough 300 may be deployed with the drawbar 308 in the loading position). Following the deployment of the plough 300, the cable may then be loaded into the receiving section, the drawbar 308 moved to the towing position and the plough 300 towed to form a trench, the cable being deposited therein during the towing process. In other examples, the plough 300 may be provided initially with the drawbar 308 in the towing position. Once deployed, the drawbar 308 may then be moved to the loading position so the cable can be then loaded in the receiving section.
[0098] In some examples, it may be required to also move/reposition other components within the plough 300 to allow the cable to be top-loaded. For example, the bell mouth 324 and/or the depressor 370 may be movable between a loading position (in which the cable can be loaded into the receiving section along the loading path 380) and an operational position (i.e. the position during a ploughing operation).
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[0101] For lifting the depressor 370, the support structure 372 is connected with the base frame of the plough 300 via an actuator 373 for actuating the support structure 372 (and the depressor 370) with respect to the plough 300 towards and away from said trenching means 306.
[0102] In this example, as illustrated in
[0103] In this example, the plough 500 is suspended (and subsequently lowered) by the tow-line 509 that will be used to tow the plough 500, for example with the tow-line 509 attached to the drawbar of the plough 500 in the launch and recovery position. However, in other examples a separate tow-line, chain or cable may be used to deploy the plough 500. In such examples, the drawbar of the plough 500 may initially be in the loading position.
[0104] The deployed plough 500 is illustrated in
[0105] As outlined below, certain aspects of the advantages described above have advantages over known devices for providing an elongate element in a seabed. For example, rotating the drawbar around a (substantially) vertical axis (i.e. moving the drawbar in a horizontal plane) to clear the loading path for loading the plough from above helps to prevent excess slack in the towline which could subsequently catch and snag. For example, when rotating the drawbar around a horizontal axis only (i.e. moving the drawbar in a vertical plane) to clear the loading path for top loading, one of the tow cables (connected at an end of the drawbar) may become slack. The slack cable can obstruct the loading of the cable. This is avoided by rotating the drawbar around a vertical axis, such that tension is maintained in both tow cables (connected at the ends of the drawbar).
[0106] In the above described examples, the trench forming means is a trench knife. However in other examples, other suitable trench forming means may be used, for example a jet cutting means or similar may be used.
[0107] The device may include grabbing or capturing means for grabbing or capturing the elongate element. That is, the grabbing or capturing means may grab the elongate element and actively draw it in, or deposit it within, the receiving section.
[0108] The device may include guiding means 327, 328, for guiding the cable towards the receiving section 380. The guiding means 327, 328 may be configured to guide the cable 350 from above the plough 300, into the receiving section 380 and/or direct the cable towards the receiving section 380. In some examples, the guiding means may include a detection system configured to detect the approach of the cable to the device during the loading process. The detection system may include at least one sonar system, for example forward and aft upwardly (nominally) facing sonar systems. The detection system would be utilised by the device to manoeuvre the cable so as to land correctly in the plough.
[0109] It would be understood that although the above described arrangements are described as being configured for top-loading, they may also be loaded axially (i.e. through loaded through the bell mouth into the receiving section).
[0110] It will be clear to a person skilled in the art that features described in relation to any of the embodiments described above can be applicable interchangeably between the different embodiments. The embodiments described above are examples to illustrate various features of the invention.
[0111] Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.
[0112] A normal reference frame relating to (components of) the plough may be used when assessing the orientation thereof. Accordingly, when the plough is positioned on a flat ground surface, “horizontal” is parallel to said flat ground surface, and “vertical” is perpendicular to said flat ground surface (i.e. upwards from said flat ground surface), even when said flat ground surface is inclined.
[0113] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.