Holding device and method for placing object on offshore platform

Abstract

The invention discloses a holding device and method for placing an object onto an offshore platform. The invention relates to a holding device (1) for attaching an object (2) to a lifting device (3) and for placing the object (2) on a platform (4) of an offshore wind turbine, the holding device (1) comprising a main structure (5) for attachment to a lifting part (6) of the lifting device (3) and a plurality of holding ropes (7) for attachment to attachment points (8) of the object (2), wherein the retaining cords (7) are attached to the main structure (5) spaced apart from each other. A retaining rope (7) of the plurality of retaining ropes (7) is attached to the main structure (5) by a plurality of winches (9), where the winches (9) are configured to be independently operated by a control device (10), where the control device (10) is configured to operate the winches (9) in a manner that compensates for the oscillating movement of the lifting device (3). The invention also relates to a method for placing an object (2) onto a platform (4) of an offshore wind turbine.

Description

Technical Field

[0001] The invention relates to a holding device for attaching an object to a lifting device and for placing the object on a platform of an offshore wind turbine. The holding device comprises a main structure for attachment to a lifting part of the lifting device and a plurality of holding ropes for attachment to attachment points of the object. The holding ropes are attached to the main structure at intervals from one another. The invention also relates to a method for placing an object on a platform of an offshore wind turbine. Background Art

[0002] An offshore wind turbine comprises a plurality of parts and devices arranged on a platform of a tower of the wind turbine. A part can be, for example, in the form of a skid or a container. Within the scope of the present invention, such a part, device, assembly or the like is denoted as an "object".

[0003] For offshore wind turbine applications, such objects are typically transported by ship to the vicinity of the wind turbine and placed onto the platform by, for example, a crane mounted on the ship.

[0004] A problem with the placement procedure is the unwanted relative movement of the object to be placed and the platform due to external disturbances like swells and high winds.There are two basically known different methods for safely placing objects in such offshore environments.

[0005] According to a first method, a jackup vessel is used. The jackup vessel can be lifted out of the water by a mobile frame that can be deployed on the seabed. Thus, the vessel and the crane mounted to the vessel are decoupled from the surge. According to a second method, a heave compensating crane is used. Such a heave compensating crane has high-tech electrical equipment for providing the necessary movement to compensate for surges and high winds.

[0006] Known devices and methods for placing objects onto platforms of offshore wind turbines have the disadvantage of relatively high operating costs, for example compared to standard vessels without jack-up functionality and with ordinary cranes that do not provide heave compensation. Furthermore, the availability of such special vessels is relatively low. Therefore, parallelization of certain offshore maintenance processes that require heave compensation is almost impossible. Besides this, in the event of a breakdown of such a vessel, it can take a long time until a replacement vessel is available. Jack-up vessels have the additional disadvantage of not providing gust compensation. Summary of the invention

[0007] Therefore, the object of the present invention is to eliminate or at least partially eliminate the above-described disadvantages in the case of placing an object on a platform of an offshore wind turbine. In particular, the object of the present invention is to create a device and a method for placing an object on a platform of an offshore wind turbine, which has improved flexibility and / or avoids such high operating costs in a simple and cheap manner.

[0008] The above-mentioned objects are achieved by the claims. Accordingly, the problem is solved by a holding device for attaching an object to a lifting device and for placing an object on a platform of an offshore wind turbine having the features of the independent claim 1 and by a method for placing an object on a platform of an offshore wind turbine having the features of the dependent claim 12. Further features and details of the invention emerge from the dependent claims, the description and the drawings. Features and details described in connection with the holding device according to the invention naturally also apply to features and details in connection with the method according to the invention and vice versa, so that with regard to the disclosure of the various aspects of the invention, reference is or can always be made to one another.

[0009] According to a first aspect of the invention, the object is achieved by a holding device for attaching an object to a lifting device and for placing the object on a platform of an offshore wind turbine. The holding device comprises a main structure for attachment to a lifting part of the lifting device and a plurality of holding ropes for attachment to attachment points of the object. The holding ropes are attached to the main structure at intervals from each other. According to the invention, holding ropes of the plurality of holding ropes are attached to the main structure via a plurality of winches, wherein the winches are configured to be independently operated by a control device. The control device is configured to operate the winches in a manner that compensates for the swinging movement of the lifting device.

[0010] The lifting device can be configured as a crane, for example. The lifting device can include a wire rope with a crane hook at one end. Preferably, the crane is configured as a standard crane without means for heave compensation. In other words, the holding device can be used by a standard lifting device to save investment and operating costs.

[0011] Within the scope of the present invention, a holding device is considered to be an intermediate device configured to be interposed between a lifting device and an object to be lifted. The holding device comprises at least a main structure, a plurality of winches and holding ropes for holding the object.

[0012] Preferably, the primary structure consists of a plurality of beams, such as steel beams or the like. The beams can have a rectangular cross section. Preferably, the beams are configured as an O-profile, screwed or welded together for forming the primary structure. The primary structure is configured to be attached to a lifting device, such as a hook or a strap attached to the lifting device.

[0013] The holding rope is configured to be attached to an attachment point of an object. For this purpose, the holding rope may include an attachment device (such as a hook, a carabiner or the like) for engaging an eyelet, a sling or the like of the object or an additional fastening device (such as a rope, a cord, a slide rail or the like) for fastening the object. The attachment device can be fixed to a first end section of the holding rope. Preferably, the holding rope has a circular or rectangular cross section. The second end section of the holding rope engages with a winch. Preferably, the holding device includes four holding ropes.

[0014] The winches are attached to the main structure (e.g. by bolts). The winches are configured to be independently operated by the control device. This means that for example one of the winches can move up or down while one or more of the other winches is idling, moving in another direction and / or at a different speed. Preferably, the holding device comprises four winches.

[0015] The control device is configured to operate the winch. The control device can be arranged at a position different from the main structure and the winch, for example at a control center of a crane, a ship, a wind turbine (for example on a platform) or a similar position. Alternatively, the control device can be arranged at any other part of the main structure, the winch or the holding device. Preferably, the control device is configured to determine the relative movement of the object to the platform. Alternatively or additionally, the control device can be configured to detect wave height, speed and direction. Alternatively or additionally, the control device can be configured to determine wind speed and wind direction. The control device can be configured to communicate with the winch by wire or wirelessly. The power supply for operating the winch can be provided by a cable. The cable can be connected to the crane and / or the ship.

[0016] The holding device according to the invention has the advantage over conventional lifting devices that heave compensation is provided in a simple and inexpensive manner. By operating the winches independently, the control device can compensate for the relative movement of the lifting device to the offshore platform. Thus, an expensive ship or jack-up vessel with a heave compensation crane can be replaced by a standard ship with a standard crane. Furthermore, since the holding device can be manufactured at relatively low cost, the availability of the holding device is relatively high compared to standard offshore lifting solutions. Thus, placement operations of different objects can be performed simultaneously by using more ships.

[0017] According to a preferred further development of the invention, the holding device can provide a main structure configured as a frame, wherein the winches are arranged at the corners of the main structure. The frame can have a rectangular shape with a long side and a short side. The frame can consist of a metal profile. Preferably, the metal profile has a rectangular cross section. Preferably, the winches are arranged at the corner sections of the frame. Preferably, the frame has a projecting plane of a standard 20-foot container or a standard 40-foot container. This has the advantage that, in a simple and inexpensive manner, a stable holding device is provided, which can be easily attached to a crane in order to provide reliable heave compensation.

[0018] According to the invention, it is preferred that the primary structure comprises an adapter device for coupling to a load hook of a lifting device. The adapter device can be configured as a hook, a shackle, an eyelet or the like for connecting to an interface of a lifting device, such as a plurality of lifting straps, hooks or the like. This has the advantage that a fastening connection to a standard lifting device can be easily established in a simple and inexpensive manner.

[0019] More preferably, the control device is configured to operate the winch in such a way that the main structure is kept in a horizontal alignment. The horizontal alignment can be an imaginary flat sea surface relatively free of waves or a platform of a wind turbine. In order to establish the horizontal alignment, the control device is configured to operate the winch independently in order to compensate for the rocking movement of the vessel with the lifting device due to disturbances of the sea. Preferably, the control device is configured to place the object onto the platform in cooperation with the lifting device, for example by keeping the holding device in a constant relative position with respect to the lifting device or by lowering the object in the direction of the platform with the lifting device. In both cases, the holding device can lower the object until the object is arranged on the platform. This has the advantage that the procedure for deploying the object onto the platform can be improved in a simple and inexpensive manner.

[0020] In a particularly preferred embodiment of the invention, a generator and / or a battery is arranged at the main structure for providing electricity to the winch. Preferably, the generator and / or the battery are configured to provide electricity to the control device. In these ways, the holding device can be provided with electricity even when the lifting device is idling or without electricity. No power cables or power interfaces are required for connecting the holding device to the ship or the lifting device. Therefore, the compatibility of the holding device is further improved. This has the advantage that the process of coupling the holding device to the lifting device is uncomplicated in a simple and inexpensive manner. In addition, heave compensation can be provided independently of the operating state of the lifting device and the ship.

[0021] Preferably, the control device is arranged at the main structure. Preferably, the control device is arranged in a protective housing for protecting the control device from environmental influences. Preferably, the protective housing is attached to a profile element of the main structure. Alternatively, the protective housing can be at least partially composed of a profile element of the main structure. Thus, the control device can be arranged in a profile element of the main structure. In these ways, the control device is well protected. This has the advantage that the process of coupling the holding device to the lifting device is uncomplicated in a simple and inexpensive manner. Furthermore, the independence of the heave compensation of the holding device can be improved.

[0022] According to a preferred embodiment of the invention, a sensor is arranged at the main structure for detecting the environment of the main structure. Preferably, two or more sensors are provided. Thus, a better detection of the relative orientation of the object to the platform is provided. Furthermore, in the event of a failure of one sensor, a reliable detection of the environment of the main structure is still provided by the other sensors. The sensor is preferably connected to the control device. The sensor can be a radar sensor, a lidar sensor or the like. Preferably, more different sensors are provided in order to provide reliable detection under different environmental conditions. This has the advantage that, in a simple and inexpensive manner, the heave compensation can be improved. Thus, a safer placement of the object on the platform is provided.

[0023] Particularly preferably, the sensor is configured to detect the object to be lifted and / or to detect the environment of the object to be lifted. By detecting the object to be lifted, the control device obtains information about the relative position and / or movement of the object with respect to the main structure. By detecting the environment of the object, the control device obtains information about the relative position and / or movement of the holding device with respect to the platform, which is usually caused by disturbances of the sea through the ship. With this information, for example, swinging movements of the object can be compensated by respectively operating the winch. This has the advantage that, in a simple and inexpensive manner, the heave compensation can be improved. Thus, a safer placement of the object on the platform is provided.

[0024] According to a preference of the present invention, the holding device comprises a sensing device for attachment to the object to be lifted, the sensing device being configured to sense the alignment of the object to be lifted with respect to the horizontal plane. Preferably, the sensing device is configured to sense the direction of gravity with respect to the orientation of the sensing device. A sensing device comprising an acceleration sensor can be provided. Further preferably, the sensing device is encapsulated in order to protect the sensing device from environmental influences that can affect the measurements of the sensing device. In order to attach the sensing device to the object, the sensing device can comprise a magnet, a suction cup or the like. In order to transmit data to the control device, the sensing device can have a wireless transmitter, a data cable, a data connector plug or the like. By means of the sensing device, the control device can be provided with additional data for operating the winch. This has the advantage that heave compensation can be improved in a simple and inexpensive manner. Thus, a safer placement of the object onto the platform is provided.

[0025] Preferably, the holding rope comprises steel wire and / or dyneema rope. Such a holding rope is strong enough for lifting heavy loads and has a long durability. This has the advantage that the reliable operation of the holding device with fewer maintenance requirements can be ensured in a simple and inexpensive manner.

[0026] Further preferably, the holding device comprises four holding ropes and four winches, wherein the winches are arranged identically at the main structure. For such a configuration, the main structure is preferably a rectangle with different side lengths. The winches are preferably arranged in the corner regions of the main structure. This has the advantage that the holding device can be specifically configured to hold an object with a rectangular face (such as a container, a box, a slide or the like) in a simple and inexpensive manner.

[0027] According to a second aspect of the present invention, this object is achieved by a method for placing an object onto a platform of an offshore wind turbine. The method comprises:

[0028] - providing a holding device according to the first aspect of the present invention for a lifting device,

[0029] - fixing the object to a plurality of holding ropes,

[0030] - lifting the holding device together with the object by means of the lifting device,

[0031] - moving the object by means of the lifting device above the deployment position,

[0032] - operating the winches by means of the control device to hold the object in a predetermined orientation with respect to the platform, and

[0033] - placing the object onto the deployment position.

[0034] The holding device can be arranged at the lifting device (eg a hook, shackle, rope or the like of the lifting device) before or after the object is fixed to the holding device.The object is fixed to the holding rope (eg by means of a hook, shackle or the like).

[0035] When the holding device is attached to the lifting device and the object is attached to the holding device, the lifting device moves the holding device together with the object above a deployment location of the object, such as a platform of a wind turbine.

[0036] For heave compensation, the control device operates the winch of the holding device. Thus, the object is held in a predetermined orientation (e.g. horizontal alignment) relative to the platform. Furthermore, the object is placed onto the platform. Preferably, heave compensation is performed until the object is firmly placed on the platform.

[0037] The method for placing an object onto a platform of an offshore wind turbine according to the invention has all the advantages already described for the holding device according to the first aspect of the invention. Accordingly, the method according to the invention has the advantage over conventional methods that heave compensation is provided in a simple and inexpensive manner. By operating the winches independently, the control device is able to compensate for the relative movement of the lifting device to the offshore platform. Thus, an expensive ship or jack-up vessel with a heave compensation crane can be replaced by a standard ship with a standard crane. Furthermore, since the holding device can be manufactured at relatively low cost, the availability of the holding device is relatively high compared to standard offshore lifting solutions. Thus, the placement operations of different objects can be performed simultaneously by using more ships.

[0038] Preferably, placing the object on the deployment position is at least partially performed by a winch. In other words, the winch is operated to provide at least two different technical functions. According to a first technical function, the winch is operated to provide heave compensation for the object so as to keep the object in a predetermined alignment with respect to the platform. This generally means forward and backward movement of the winch and / or movement at different speeds. According to a second technical function, the winch is operated to lower the object in the direction of the platform. Preferably, the two technical functions are performed simultaneously with superimposed movements. This has the advantage that the quality of the process of placing the object on the platform is further improved in a simple and inexpensive manner.

[0039] It is further preferred that placing the object on the deployment position is at least partially performed by a lifting device. This means that the lifting device lowers the object while the holding device provides heave compensation. Preferably, the holding device only provides heave compensation in order to avoid unwanted swinging of the object. Alternatively, the lifting device enables the object to be lowered together with the holding device. Thus, the deployment time for deploying the object on the platform can be reduced. This has the advantage that the quality of the process of placing the object on the platform is further improved in a simple and inexpensive manner.

[0040] Preferably, a sensor is used to determine the relative position of the object with respect to the platform, wherein the winch is operated by a control device to hold the object in a predetermined orientation with respect to the platform based on the determined relative position. By using a sensor for determining the relative position of the object with respect to the platform, information about the swaying motion of the object due to sea disturbances and wind is obtained. In addition, the heave compensation mass performed by the winch can be monitored online. Therefore, heave compensation errors can be identified and corrected in real time. This has the advantage of further improving the quality of the process of placing the object on the platform in a simple and inexpensive manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Further advantages, features and details of the present invention are set forth in the following development, in the following description, working examples of the present invention are described in detail by reference to the accompanying drawings. Thus, the features from the claims as well as the features mentioned in the description can be essential for the present invention when taken alone or in any combination. In the drawings:

[0042] Figure 1 A schematic perspective view of a lifting device with heave compensation according to the prior art is illustrated,

[0043] Figure 2 A schematic side view of a jack-up vessel according to the prior art is illustrated,

[0044] Figure 3 A schematic perspective view of a preferred embodiment of a holding device in a first state according to the present invention is illustrated,

[0045] Figure 4 Illustrated in a second state Figure 3 of the

[0046] Figure 5 A schematic flow chart of a method according to a preferred embodiment of the present invention is illustrated.

[0047] Elements having the same function and effect are, in Figure 1-5 each element is denoted by the same reference numeral. DETAILED DESCRIPTION

[0048] In Figure 1 , in a schematic perspective view, a lifting device 3 with heave compensation according to the prior art is illustrated. The lifting device 3 is arranged on the deck of the vessel and, therefore, is exposed to sea disturbances. The lifting device 3 is configured as a heave compensation crane and is used to place an object 2 at a deployment position D on an offshore platform 4. In this example, the object 2 is a container.

[0049] Figure 2A schematic side view of a jack-up vessel 16 according to the prior art with a mounted lifting device 3 is illustrated. The lifting device 3 is configured as a standard crane. The jack-up vessel 16 is raised on supports 17 and, therefore, is no longer exposed to disturbances of the sea. Therefore, this does not require a lifting device 3 for heave compensation.

[0050] exist Figure 3 , a preferred embodiment of a holding device 1 according to the invention is illustrated in a schematic perspective view in a first state.

[0051] exist Figure 4 In the schematic perspective view, the second state Figure 3 The holding device 1 comprises a main structure 5 configured as a rectangular frame. In each corner of the main structure 5, a winch 9 with a holding rope 7 is arranged. The holding rope 7 is attached to an attachment point 8 of an object 2. In this example, the object 2 is configured as a container. On top of the object 2, an optional sensing device 15 for sensing the horizontal alignment of the object 2 is arranged.

[0052] For operating the winch 9, a control device 10 is provided. In this example, the control device 10 is arranged at the main structure 5, for example, in a profile beam of the main structure 5. For providing electricity for the winch 9 and the control device 10, an optional battery 13 is arranged at the main structure 5, for example, in a profile beam of the main structure 5. Alternatively or additionally, a generator can be provided, for example at the main structure 5, in particular, in a profile beam of the main structure 5. In this example, the control device 10 is configured to operate the winch based on the sensing data of the sensing device 15.

[0053] Furthermore, a plurality of sensors 14 are arranged at the main structure 5. In this case, the sensors 14 are arranged at corner sections of the main structure 5. The sensors 14 are configured to sense the object 2 and / or the environment of the object 2, in particular the platform 4 of an offshore wind turbine. In this example, the control device 10 is configured to operate the winch based on the sensor data of the sensors 14.

[0054] Furthermore, the holding device 1 comprises an adapter device 11 with four straps, which are attached to the corners of the primary structure 5. The adapter device 11 is attached to a load hook 12 of a lifting part 6 of a lifting device 3. By these means, the holding device 1 is movable by a lifting device.

[0055] Figure 5A schematic flow chart of a method according to a preferred embodiment of the invention is illustrated. According to a first method action 100, a lifting device 3 is arranged at an installation site of an offshore wind turbine on a floating vessel. The lifting device 3 is a standard crane without an integrated heave compensation system. The lifting device comprises a lifting component 6 with a load hook 12. At the load hook 12, an adapter device 11 of a holding device 1 according to the invention is attached. In a second method action 200, an object 2 is fixed to a plurality of holding ropes 7. Preferably, each holding rope 7 comprises a shackle or hook, which is attached to an attachment point 8 (e.g. an eyelet) of the object 2.

[0056] In a third method action 300, the holding device 1 is lifted together with the object 2 by the lifting device 3. According to a fourth method action 400, the lifting device 3 moves the object 2 above the deployment position D of the platform 4 of the wind turbine. The deployment position D is the position of the platform 4 where the object 2 must be deployed. In a fifth method action 500, the control device 10 operates the winch 9 to hold the object 2 in a predetermined orientation relative to the platform 4. Thus, heave compensation is provided. In a sixth method action 600, the object 2 is placed onto the deployment position D of the platform 4. The lowering of the object 2 can be done by the lifting device 3 and / or the holding device 1.

Claims

1. A holding device (1) for attaching an object (2) to a lifting device (3) and for placing the object (2) on a platform (4) of an offshore wind turbine, the holding device (1) comprising a main structure (5) for attachment to a lifting part (6) of the lifting device (3) and a plurality of holding ropes (7) for attachment to attachment points (8) of the object (2), wherein the holding ropes (7) are attached to the main structure (5) at intervals from one another, Features The holding ropes (7) of the plurality of holding ropes (7) are attached to the main structure (5) by means of a plurality of winches (9), wherein the winches (9) are configured to be independently operated by means of a control device (10), wherein the control device (10) is configured to operate the winches (9) in a manner that compensates for the swinging movement of the lifting device (3).

2. The holding device (1) according to claim 1, Features The main structure (5) is configured as a frame, wherein the winch (9) is arranged at the corners of the main structure (5).

3. The holding device (1) according to claim 1 or 2, Features The primary structure (5) comprises an adapter device (11) for coupling to a load hook (12) of the lifting device (3).

4. Holding device (1) according to any one of the preceding claims, Features The control device (10) is configured to operate the winch (9) in such a way as to maintain the primary structure (5) in horizontal alignment.

5. Holding device (1) according to any one of the preceding claims, Features A generator and / or a battery (13) is arranged at the main structure (5) for providing electricity to the winch (9).

6. Holding device (1) according to any one of the preceding claims, Features The control device (10) is arranged on the main structure (5).

7. Holding device (1) according to any one of the preceding claims, Features A sensor (14) is arranged at the main structure (5) for detecting the environment (E) of the main structure (5).

8. The holding device (1) according to claim 7, Features The sensor (14) is configured to detect the object (2) to be lifted and / or to detect an environment (E) of the object (2) to be lifted.

9. Holding device (1) according to any one of the preceding claims, Features The holding device (1) comprises a sensing device (15) for attachment to the object (2) to be lifted, the sensing device (15) being used to sense the alignment of the object (2) to be lifted with a horizontal plane.

10. Holding device (1) according to any one of the preceding claims, Features The retaining rope (7) comprises a steel wire and / or a Dyneema rope.

11. Holding device (1) according to any one of the preceding claims, Features The holding device (1) comprises four holding ropes (7) and four winches (9), wherein the winches (9) are arranged equally at the main structure (5).

12. A method for placing an object (2) on a platform (4) of an offshore wind turbine, the method comprising: - providing a lifting device (3) with a holding device (1) according to any one of the preceding claims, - securing the object (2) to the plurality of holding ropes (7), - lifting the holding device (1) together with the object (2) by means of the lifting device (3), - moving the object (2) by means of the lifting device (3) above the deployment position (D), - operating the winch (9) by means of the control device (10) to keep the object (2) in a predetermined orientation relative to the platform (4), and - Placing said object (2) in said deployment position (D).

13. The method according to claim 12, Features Placing the object (2) in the deployment position (D) is at least partially performed by means of the winch (9).

14. The method according to claim 12 or 13, Features Placing the object (2) in the deployment position (D) is at least partially performed by the lifting device (13).

15. The method according to any one of claims 12 to 14, Features A sensor (14) is used to determine the relative position of the object (2) with respect to the platform (4), wherein operation of the winch (9) by the control device (10) to maintain the object (2) in a predetermined orientation relative to the platform (4) is performed based on the determined relative position.

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