A storage and deployment unit for a coilable element and a method of handling a coilable element

Abstract

 A device (12) for storing, transporting and deploying an elongate, coilable element (14), has a feeding unit (4) releasably connected to a storage unit (1). The feeding unit comprises first guiding means (17) and second guiding means (16) for feeding the element (14) into and out of the storage unit, and the storage unit has a storage region (19) for the element

Description

Field of the invention

[0001] The invention concerns the storage, transportation and deployment of coilable elongate elements, such as cables.

Background of the invention

[0002] Offshore facilities, such as offshore wind power turbines and oil rigs, are normally connected to cables for supplying power to and/or from the facility or for communicating electrical signals to and/or from the facility. Particularly in the wind farm industry, several tens of wind power turbines may be interconnected by a network of cables. Offshore wind power turbines may be arranged with separation distances ranging between 500 metres and 1000 metres.

[0003] Laying such "in-field" cables between individual wind power turbines is performed by traditional cable-laying ships or barges, which are loaded with the necessary cable at shore and then sails to the offshore location where it moves between the offshore turbines in order to lay the various lengths of cable. The total length of cable required may be in the order of 100 kilometres, all spooled onto the ship's carousel or turntable. Alternatively, individual in-field cable lengths are spooled onto smaller reels and subsequently loaded onto the installation vessel into designated reel stands. The former method is the preferred one, as each cable length is cut to suit the as-installed positions of the turbines and the actual laying track of the cable in question; hence the required over-length is minimized, as is the cost. However, load-out of a long cable onto a carousel on a vessel is a time consuming and hence costly operation.

[0004] The present applicant has devised and embodied this invention in order to overcome the shortcomings of the prior art and to obtain further advantages.

Summary of the invention

[0005] The invention is set forth and characterized in the main claims, while the dependent claims describe other characteristics of the invention.

[0006] It is thus provided a device for storing, transporting and deploying an elongate, coilable element, characterized by a storage unit having a storage region for the element; and supports by means of which the device may be placed on, and skidded along, a surface.

[0007] In one embodiment, the device comprises a feeding unit releasably connectable to the storage unit and having first guiding means and second guiding means for feeding the element into and out of the storage unit.

[0008] In one embodiment, the storage unit comprises an opening into the storage region, and first connectors configured for connection to corresponding second connectors on the feeding unit.

[0009] In one embodiment, the first connectors are in the region of the opening, whereby the first guiding means is arranged in the vicinity of the opening when the feeding unit and the storage unit are connected.

[0010] In one embodiment, the feeding unit further comprises a first motion control device, operable for feeding the element into or out of the storage region.

[0011] The storage region has preferably a circular cross-section and a central hub. In one embodiment, the first guiding means is arranged coaxially with the hub centre axis, and the axis is substantially vertical and the feeding unit is arranged on top of the storage unit.

[0012] It is also provided a system for storing, transporting and deploying an elongate, coilable element, characterized by one or more of the devices according to the invention arranged on a carrier; said carrier further comprising a second motion control device arranged to receive the element as it is being fed out of the second guiding means, and a third element guide for conveying the element off of the carrier.

[0013] The carrier is in one embodiment a ship having deck space for one or more of the devices according to the invention. The elongate, coilable element is preferably a cable, e.g. a cable having one layer of reinforcement.

[0014] It is also provided a method of storing and transporting an elongate coilable element, characterized by the steps of

a) loading desired quantities of coilable element into a desired number of containers;

b) storing the containers at an on-shore location;

c) at a desired time, loading the containers onto a transportation vehicle; and

d) transporting the containers on the vessel to a designated location.

[0015] In one embodiment of the method, the loading in step c comprises skidding.

[0016] The vehicle does in a preferred embodiment comprise a ship having a deck space for storing the containers.

[0017] The method of the invention is preferably executed using the invented device and system.

[0018] With this invention, standard supply vessels may be used as platforms for installing the cable. The mobilisation and demobilisation cost is significantly reduced, compared to the vessels of the prior art.

Brief description of the drawings

[0019] These and other characteristics of the invention will be clear from the following description of a preferential form of embodiment, given as a non-restrictive example, with reference to the attached drawings wherein:

Figure 1 is a side view of a ship carrying the invented transportation and deployment device, and shows cable installation being performed from the invented device;

Figure 2 is a top view of the ship shown in figure 1;

Figure 3 is a side view of the transportation and deployment device;

Figure 4 is a side view of the cable feed unit, seen in the direction D as indicated in figure 3;

Figure 5 is a top view of the cable trough;

Figure 6 is a side view of the cable trough, seen in the direction C as indicated in figure 5;

Figure 7 is a side view of the cable trough, seen in the direction A as indicated in figures 5 and 8;

Figure 8 is a top view of the cable trough, seen in the direction B as indicated in figure 5;

Figure 9 is a side view of the invented transportation and deployment device on a quay, ready for loading into a ship; and

Figure 10 is a side view of the invented transportation and deployment device on a quay being skidded aboard a ship.

Detailed description of a preferential embodiment

[0020] The invented transportation and deployment device 12 generally comprises a container, or trough, 1 for holding a coilable element - such as a coilable cable - 14, and a releasable feed unit 4.

[0021] The container 1 is in the illustrated embodiment basically a metal cage, or trough, having a central hub 18 and curved inner side walls, thus defining a toroid-shaped storage compartment 19, into which the cable is coiled. The central hub radius is determined by the minimum bending radius for the coilable cable. The container comprises skidding beams 2, separated by slots 3, and upper, removable beams 11 which serve as stiffeners when the container is being lifted. Lifting lugs 22 are provided, whereby the container may be lifted, e.g. via slings 20 and a crane (not shown).

[0022] The feed unit 4 is designed to be positioned above the upward opening 24 of the container 1, and comprises pegs 26 for mating engagement with corresponding receptacles 25 on the container 1. The feed unit comprises a cable guide pipe 16, leading between the side of the feed unit and a guide funnel 17 which is positioned in an upper, central region of the feed unit, concentric with the hub 18 (see figure 3) and opening downwards towards the container opening 24. The guide pipe 16 comprises a tensioner 5, by means of which the coilable elongate element (e.g. cable) may be moved within the pipe, and hence into or out of the compartment 19.

[0023] In use, coilable cable may be loaded into the storage compartment 19 of the container 1 at a cable manufacturing plant, e.g. via the feed unit 4 and using the tensioner 5 and guide pipe 16. Once a container has been filled with the desired length of cable, the feed unit is removed. Temporary beams 11 are attached to the container, and the container may be shipped to a load-out quay 23. The feed unit may be used to fill subsequent containers.

[0024] The invented device therefore allows a cable manufacturer to fill a number of containers, independently of the presence of any installation vessel. The containers may be stored at the cable manufacturer's premises until an installation vessel arrives and it is convenient to load the containers onto the vessel. As the device (container and feed unit) is modular and self-contained, the installation vessel need not be a specialized installation vessel, but may be any vessel with dynamic positioning capabilities and having sufficient deck space for the required number of containers. A conventional supply vessel with an open stern would be suitable.

[0025] Figures 9 and 10 show two containers 1a,b being skidded from the quay 23 and onto the deck 21 of a vessel 15, via a skidding ramp 8. The ship may be any conventional ship, having the deck space to hold the containers.

[0026] Figure 1 shows installation of a cable 14. The cable is coiled inside the rearward container 1a and fed out by means of the feed unit 4 as described above. The cable extends through a tensioner 9 on the ship and through a guide chute 10, and down into the water S.

Claims

1. A device (12) for storing, transporting and deploying an elongate, coilable element (14), characterized by
a storage unit (1) having a storage region (19) for the element; and supports (2) by means of which the device may be placed on, and skidded along, a surface (21, 23).

2. The device of claim 1, further comprising
a feeding unit (4) releasably connectable to the storage unit (1) and having first guiding means (17) and second guiding means (16) for feeding the element (14) into and out of the storage unit.

3. The device of claim 2, wherein the storage unit (1) comprises an opening (24) into the storage region (19), and first connectors (25) configured for connection to corresponding second connectors (26) on the feeding unit (4).

4. The device of claim 3, wherein the first connectors (25) are in the region of the opening (24), whereby the first guiding means (17) is arranged in the vicinity of the opening when the feeding unit and the storage unit are connected.

5. The device of any one of the preceding claims, wherein the feeding unit further comprises a first motion control device (5), operable for feeding the element into or out of the storage region.

6. The device of any one of the preceding claims, wherein the storage region (19) has a circular cross-section and a central hub (18).

7. The device of claim 6, wherein the first guiding means (17) is arranged coaxially with the hub (18) centre axis (z).

8. The device of claim 7, wherein the axis (z) is substantially vertical and the feeding unit (4) is arranged on top of the storage unit (1).

9. A system for storing, transporting and deploying an elongate, coilable element (14), characterized by
one or more of the devices according to any one of claims 1-8 arranged on a carrier (15); said carrier further comprising a second motion control device (9) arranged to receive the element (14) as it is being fed out of the second guiding means (16), and a third element guide (10) for conveying the element off of the carrier.

10. A method of storing and transporting an elongate coilable element (14), characterized by the steps of

a) loading desired quantities of coilable element into a desired number of containers (1a,b);

b) storing the containers at an on-shore location;

c) at a desired time, loading the containers onto a transportation vehicle (15); and

d) transporting the containers on the vessel to a designated location.

11. The method of claim 10, wherein the loading in step c comprises skidding.

12. The method of claim 10 or claim 11, wherein vehicle comprises a ship (15) having a deck space (21) for storing the containers.

13. The method of any one of claims 10 - 12, using the device (12) of any one of claims 1-8.

14. The method of any one of claims 10 - 12, using the system of claim 9.

Drawing