Lifting system for lifting single pile, hanger, vessel and method for storing single pile on vessel

Abstract

A lifting system (1) for lifting a single pile (3, 6) comprises a pair of coupling members (2) for coupling to the single pile at a distance from each other in the longitudinal direction of the single pile. Each coupling member has: a support (7) for coupling to a hoisting apparatus, such as a crane (21); a sling (8) for at least partially surrounding the single pile, the sling being suspended from the support so as to form a loop; and a tightening device (14) for changing the length of the sling.

Description

[0001] The invention relates to a lifting system for lifting a single pile

[0002] Offshore wind turbines can be installed on top of a monopile, which is driven into the seabed. Typically, the monopile is manufactured at an onshore location and loaded onto a vessel at a pier. The monopile is transferred from the pier to the vessel by a crane and stored on the deck of the vessel in a horizontal orientation. The crane has a lifting cable from which a hanger beam is suspended. Before the monopile is lifted, two slings are connected around the monopile and the slings are attached to the hanger beam. After the monopile is placed on the deck, the slings are disconnected from the monopile and connected to another monopile that will be transferred from the pier to the vessel. After the monopile is placed on the deck, the vessel sails to the offshore site where the monopile will be installed into the seabed.

[0003] At the offshore site, a crane on board a vessel can lift the stored monopile after connecting the same or different slings (including two slings or different slings) and transfer it to an erection device for turning the monopile into a vertical orientation. Subsequently, the monopile can be shifted to the position of the vessel, where it is lowered to the seabed and driven into the seabed by a pile driver. The disadvantage of the above operations is that they take a lot of time at the offshore site.

[0004] It is an object of the present invention to provide a lifting system in which the operating time at the offshore site is minimized.

[0005] This object is achieved by a lifting system for lifting a monopile according to the invention, the lifting system comprising: a pair of coupling members for coupling to the monopile at a distance from each other in the longitudinal direction of the monopile, wherein each coupling member has: a support for coupling to a lifting device such as a crane; a sling for at least partially surrounding the monopile, the sling being suspended from the support so as to form a loop; and a tightening device for changing the length of the loop.

[0006] The advantage of the lifting system according to the invention is that the coupling member is a relatively simple mechanical structure, which can be connected to the monopile before loading the monopile onto the ship (for example at the quay), and can remain on the monopile until the monopile is placed on the erection device of the ship. The support can be used for temporary fixing to the ship so that the monopile is suspended from the support by the sling, for example during the transportation of the monopile to the offshore site. The tightening device provides the opportunity to clamp the sling around the monopile by shortening the length of the loop. This means that the coupling member can be used as an offshore fastening tool. At the offshore site, the monopile can be easily lifted by connecting the lifting member to the support, thus avoiding the time-consuming operation of fastening the sling to each monopile. The slings of the support and the coupling member can be adapted so that when the loop is shortened, the monopile is clamped against the support.

[0007] The coupling member may be a separate unit.

[0008] The sling may be mounted or releasably mounted to the support at a first position and a second position of the support, the first position and the second position being at a distance from each other. This means that when the loop of the sling is shortened, the monopile may be clamped between the sling and the support at each coupling member.

[0009] The sling may comprise an annular element which loops around the support in the first position and in the second position. In this case, the loop of the sling, ie the portion of the annular element which is capable of supporting a monopile, is formed by two sections of the sling.

[0010] In a particular embodiment, in the second position, the sling is looped around two fixed sling guides, the two fixed sling guides being located at a distance from each other in the plane, wherein the tightening device comprises a dynamic sling guide for guiding the sling between the fixed sling guides, wherein the dynamic sling guide is movable in a transverse direction of the plane relative to the fixed sling guides. The dynamic sling guide may be operated by an actuator. The fixed sling guide may be a pin.

[0011] In the second position, the sling may be looped around two fixed sling guides located at a distance from each other. The fixed sling guides in the second position may be pins.

[0012] The support may be rigid.

[0013] The supports may be elongate elements such as beams made of steel.

[0014] The lifting system may be provided with a lifting member for coupling to a lifting device, the lifting member being releasably attached to the support. In case the coupling member is a separate unit, since the lifting members may have fixed dimensions, they are preferably applied on the monopile at a fixed distance from each other.

[0015] The lifting member may comprise a rectangular frame having two opposing sides releasably attachable to respective ones of the supports.

[0016] The invention also relates to a hanger for receiving a monopile, the hanger comprising a lifting system as described above, wherein the support element fits into a cooperating receiving element of the hanger. This is advantageous because the monopile can be easily placed in and lifted from the hanger without the need to detach the coupling member from the monopile.

[0017] In a preferred embodiment, the fixed sling guide in the first position and in the second position can be fitted to the receiver, because in this case the fixed sling guide has two functions: for guiding the sling and for being received by the receiver of the spreader.

[0018] The invention also relates to a vessel comprising a deck and a cradle, the cradle being movable through the deck.

[0019] The cradle is movable in the longitudinal direction of the deck and in the transverse direction, in the longitudinal direction for storing the monopile, for example at a distance from a crane on the vessel, and in the transverse direction to be able to change the position of the center of gravity of the monopile in the transverse direction of the vessel.

[0020] The invention also relates to a storage method for storing a monopile on a vessel comprising a cradle as described above, by using a lifting system as described above, wherein slings are mounted around the monopile and attached to respective supports at a distance from each other along the monopile to form respective loops of the slings around the monopile, respective tightening devices are operated to shorten the loops of the slings until the distance between the support and the monopile is at the desired distance, a lifting member is connected to the support, after which the support including the slings and the monopile are lifted and transferred to the cradle, where the support is placed at a receiver and the lifting member is disconnected from the support. In the resulting storage state of the monopile, the cradle carries the support, which in turn carries the monopile via the respective slings.

[0021] When a vessel sails to an offshore site for installing a stored monopile, the support can be easily coupled to the lifting member and lifted, for example to transfer the monopile to an erection device. At the erection device, the coupling member can be disconnected from the monopile by operating the tightening device and removing the support and slings from the monopile.

[0022] The invention will be explained below with reference to schematic diagrams showing embodiments of the invention.

[0023] Figure 1 is a perspective view of an embodiment of a lifting system according to the present invention, showing a monopile lifted by the lifting system and positioned above a hanger.

[0024] Figure 2 is with Figure 1 A similar view shows the monopile being received by the hanger.

[0025] Figure 3 is with Figure 2 A similar view shows another state.

[0026] Figure 4 is with Figure 3 A similar view shows the state where two monopiles are received by the hanger.

[0027] Figure 5 Yes Figure 1 A front view of the coupling member of the lifting system is shown.

[0028] Figure 6 yes Figure 5 Side view of the connecting member in direction VI.

[0029] Figure 7 is with Figure 6 A similar view shows Figure 5 Connecting member in direction VI I.

[0030] Figure 8 is with Figure 7 Similar views, but showing a different state of the coupling member.

[0031] Fig. 9 is with Figure 5 Similar views, but showing a different state of the coupling member.

[0032] Fig.10 is a top view of an embodiment of a vessel according to the present invention.

[0033] Fig.11 is with Fig.10 Similar views showing different states of the vessel.

[0034] Fig.12 is with Fig.10 A similar view shows another state of the vessel.

[0035] Figure 1 An embodiment of a lifting system 1 according to the invention is shown. The lifting system 1 comprises a pair of coupling members 2 coupled to a monopile 3 at a distance from each other in the longitudinal direction of the monopile 3. Figure 1 In the state shown, the coupling member 2 is attached to a lifting member 4 which in turn is suspended from a crane (not shown). Figure 1 A monopile 3 is shown positioned above a hanger 5 .

[0036] Figure 2 There is shown a state in which the monopile 3 is lowered and received by the hanger 5. In this state, the coupling member 2 is supported by the hanger 5. The hanger 5 is shown as two separate U-shaped frames, but they may be attached to each other. Figure 3 It is shown that after positioning the monopile 3 in the hanger 5 , the lifting member 4 is detached from the coupling member 2 , for example by a pin release mechanism, and lifted relative to the monopile 3 and the hanger 5 . Figure 4 A state is shown in which another monopile 6 is received by the hanger 5 and positioned above the monopile 3 , so that the hanger 5 comprises a stack of two monopiles 3 , 6 .

[0037] Figure 5 One of the coupling members 2 is shown. It has a rigid support 7 and a sling 8, which is suspended from the support 7 and partially surrounds the monopile 3. The sling 8 forms a loop around the monopile 3. The support 7 is an elongated element in the form of a beam, for example made of steel. The sling 8 comprises a flexible annular element, such as a rope or cable, which has loops at a first position 9 and a second position 10 of the support 7. The first position 9 and the second position 10 are located at opposite ends of the support 7. Figure 6 It is shown that in a first position 9 , the sling 8 is looped around two pins 11 of the support 7 .

[0038] Figure 7 In a second position 10, the sling 8 is shown looped around two fixed sling guides 12 in the form of pins, which are located at a distance from each other in the horizontal plane. Between the fixed sling guides 12, the sling 8 is guided by a dynamic sling guide 13 in the form of a freely rotatable wheel. The dynamic sling guide 13 can be moved perpendicularly to the horizontal plane relative to the fixed sling guides 12 by means of an actuator (not shown) in order to vary the length of the loop of the sling 8 around the monopile 3. In this way, a tightening device 14 is produced for connecting the sling 8 and the support 7 around the monopile 3. The latter case is in the Figures 5 to 7 It is shown in Figure 8 and Fig. 9 The situation is shown where the tightening device 14 is deactivated, leaving the sling 8 slack. Therefore, the support 7 and the sling 8 are not clamped around the monopile 3, which state can be used to couple the coupling member 2 to the monopile 3 or to detach the coupling member 2 from the monopile 3.

[0039] Reference Figure 1-4 , the lifting member 4 is releasably attached to the support 7. In the embodiment shown, the lifting member 4 has a rigid rectangular frame. The frame is provided with release mechanisms at its respective corners so as to be able to engage the support 7.

[0040] In practice, the monopile 3 may be provided with indicators, e.g. Figure 1 The line 15 is shown where the coupling member 2 should be placed so that the lifting member 4 can correctly engage the support 7 .

[0041] Figure 1-4 The hanger 5 is shown provided with an upwardly directed hook 16 defining a receptacle for receiving the pin 11 of the support 7 and the fixing sling guide 12. Furthermore, the hanger 5 is provided with an additional retaining member 17 which engages the monopile 3 in its final position in the hanger 5 so as to lock the monopile 3 in horizontal direction relative to the hanger 5.

[0042] Fig.10 Shown include Figure 4The hanger 5 of the monopile 3, 6 shown is located on a vessel 18 for transporting the monopile to an offshore site, where the monopile is installed in the seabed, for example for installing a wind turbine on top of the monopile. The monopile is transported in a horizontal orientation and is turned over at the offshore site by means of a turning device 19. The hanger 5 is movable across a deck 20 of the vessel 18 in order to move the monopile to be turned over close to a crane 21 also mounted on the deck 20. The hanger 5 can be moved in the longitudinal direction of the vessel 18 in order to use space on the deck 20 at a distance from the crane 21 for storing the monopile 3, 6, and in the transverse direction in order to move the center of gravity of the hanger 5 including the monopile 3, 6 to or close to the longitudinal center plane of the vessel 18. For this purpose, the deck 20 is provided with guide rails 22 for guiding the hanger 5, see Fig.11 .

[0043] Fig.10 It is shown that when the cradle 5 is located on the starboard side or shifted to the starboard side, the monopiles 3, 6 are loaded onto the cradle 5 from the quay (not shown), Fig.11 It is shown that the cradle 5 including the monopiles 3, 6 is then moved towards the port side. A plurality of cradles 5 may be loaded with monopiles and stored on the deck 20 before leaving to an offshore location. Fig.12 Another cradle 5 ′ is shown loaded with a monopile 3 ′, while the loaded cradle 5 is displaced away from the crane 21 .

[0044] At the offshore site, each cradle 5, 5' can be transferred towards the crane 21 so that it can lift the stored monopiles 3, 6 after coupling the lifting members 4 to each pair of supports 7 mounted to the respective monopiles.

[0045] As is clear from the above, the presence of the coupling member minimizes the operating time at the offshore site, since there is no need to connect a sling to each monopile.

[0046] The invention is not limited to the embodiments shown in the drawings and described above, which may be varied in different ways within the scope of the claims and their technical equivalents. For example, in alternative embodiments, the sling may have a different shape, such as a single rope with loops at its opposite ends. Furthermore, in alternative embodiments, the tightening device and the way of mounting the sling to the support may be different. It is also conceivable that the lifting system is provided with supports fixed to each other and at a distance from each other, instead of having coupling members as separate units.

Claims

1. A lifting system (1) for lifting a monopile (3, 6), comprising: A pair of coupling members (2) for coupling to the monopiles (3, 6) at a distance from each other in the longitudinal direction of the monopiles (3, 6), wherein each coupling member (2) has: a support (7) for coupling to a lifting device such as a crane (21); a sling (8) for at least partially surrounding the monopiles (3, 6), the sling (8) being suspended from the support (7) to form a loop; and a tightening device (14) for changing the length of the loop (8).

2. The lifting system (1) according to claim 1, wherein: The coupling member (2) is a separate unit.

3. The lifting system (1) according to claim 1 or 2, wherein: The sling (8) is mounted or releasably mounted to the support (7) at a first position (9) and a second position (10) of the support (7), the first position (9) and the second position (10) being located at a distance from each other.

4. The lifting system (1) according to claim 3, wherein: The sling (8) comprises an annular element which loops around the support (7) at the first position (9) and at the second position (10).

5. Lifting system (1) according to claims 3 and 4, wherein: In the second position (10), the sling (8) is looped around two fixed sling guides (12) which are located at a distance from each other in a plane, wherein the tightening device (14) comprises a dynamic sling guide (13) for guiding the sling (8) between the fixed sling guides (12), wherein the dynamic sling guide (13) is movable relative to the fixed sling guides (12) in a transverse direction of the plane.

6. The lifting system (1) according to claim 5, wherein: In the first position (9), the sling (8) is looped around two fixed sling guides (11) located at a distance from each other.

7. A lifting system (1) according to any one of the preceding claims, wherein: The support (7) is rigid.

8. Lifting system (1) according to any one of the preceding claims, wherein: The support (7) is an elongated element.

9. Lifting system (1) according to any one of the preceding claims, wherein: The lifting system (1) is provided with a lifting member (4) for coupling to a lifting device (21), the lifting member (4) being releasably attachable to the support (7).

10. The lifting system (1) according to claim 9, wherein: The lifting member (4) comprises a rectangular frame having two opposite sides which can be releasably attached to respective supports (7).

11. A hanger (5) for receiving a monopile (3, 6), the hanger (5) comprising a lifting system (2) according to any one of the preceding claims, wherein: The support (7) fits into a mating receiver (16) of the hanger (5).

12. The hanger (5) according to claim 11 as appended to claims 5 and 6, wherein The fixed sling guides (11, 12) at the first and second positions (9, 10) are fitted to the receiver (16).

13. A vessel (18) comprising a deck (20) and a cradle (5) according to claim 11 or 12, the cradle (5) being movable on the deck (20).

14. A vessel (18) according to claim 13, wherein: The cradle (5) is movable in the longitudinal direction and the transverse direction of the deck (20).

15. A method of storing a monopile (3) on a vessel (18) comprising a cradle (5) according to claim 11 or 12, by using a lifting system (1) according to any one of claims 1 to 10, wherein: Slings (8) are mounted around the monopile (3) and attached to respective supports (7) at a distance from each other along the monopile (3) to form respective loops of the slings (8) around the monopile (3), respective tightening devices (14) are operated to shorten the loops of the slings (8) until the distance between the support (7) and the monopile (3) is at a desired distance, a lifting member (4) is connected to the support (7), after which the support (7) including the slings (8) and the monopile (3) are lifted and transferred to the hanger (5), where the support (7) is placed at a receiver (16) and the lifting member (4) is disconnected from the support (7).

Images