Floating body and offshore wind turbine having a floating body

Abstract

The invention relates to a floating body (10) having a plurality of balls (30) arranged concentrically around a carrier (20), wherein the balls (30) are fastened to the carrier (20), at least a first subset of the balls (30) is arranged in at least a first plane and at least a second subset of the balls (30) is arranged in at least a second plane opposite to the first plane, and the balls (30) of the second plane are arranged offset with respect to the balls (30) of the first plane in such a way that the balls (30) of the second plane engage in the interspaces between the balls (30) of the first plane.

Description

[0001] Floating body and offshore wind turbine with floating body

[0002] The invention relates to a floating body. In particular, the invention relates to a floating body comprising a plurality of balls arranged concentrically around a support, wherein at least a first subset of the balls is arranged in at least one first plane and at least a second subset of the balls is arranged in at least one second plane parallel to the first plane.

[0003] Floating wind turbines, as known, for example, from EP 3 464 882 B1, have a floating foundation with a plurality of buoyancy bodies arranged thereon, hereinafter referred to as floats. For a floating offshore wind turbine to float stably, not only must the total buoyancy of the underwater part be as great as its total weight, but the part of the floats that protrudes from the water must also ensure that the system does not capsize if the turbine is tilted or if there are waves. The buoyancy volume of the floats required for this purpose accounts for at least 20% to 25% of the total buoyancy of a floating offshore wind turbine. To create stability in all directions, at least three floats are required, each of which can float up to 1,000 m 3or more buoyancy volume. The components that make up the floats are often made of steel tubes, but a shell construction made of fiberglass or an entire body made of plastic foam is also used.

[0004] These floats are not only exposed to the forces of nature such as seawater, storms, growth, UV radiation, etc., but must also be taken into account. Collisions with maintenance vessels or floating containers lost by cargo ships must also be taken into account. In the case of hollow tubes, this leads to the need to provide multiple chambers to prevent a complete loss of buoyancy and thus, under certain circumstances, the capsizing of the structure in the event of a leak. These structures must also be able to be repaired after such damage, which further increases the demands on the float structure. In addition, a not insignificant load on the structure results from the immersion depth of the floats below the water surface. When superimposed with an extreme wave, immersion depths of up to 30 m to 40 m can occur.In principle, the floating bodies must withstand not only hydrostatic loads but also dynamic wave loads, with particular attention being paid to minimizing material usage to limit the total weight of floating wind turbines. The principles for this are set out, for example, in DE 10 2019 118 564 Al "Wind turbine with a floating foundation comprising a plurality of buoyancy bodies."

[0005] The difficulty in manufacturing the floats intended for such systems is that the single-piece production of a float causes considerable problems during transport due to its size, while the small-piece production of a float entails increased material and labor costs during installation.

[0006] Although other floating bodies are known from other fields, such as CN 207129108 U, which discloses a floating body of the type mentioned above for the installation of measuring instruments for ocean research, no optimal solution seems to have been found for floating wind turbines in terms of labor and material expenditure and the associated logistical requirements.

[0007] The object of the invention is therefore to create a floating body whose production requires minimal labor and material expenditure and is also easy to transport and maintain, particularly after damage to the floating body through simple repair or replacement of a damaged component. Furthermore, due to the large demand for floating bodies for floating offshore wind turbines, special attention must be paid to the suitability of the manufacturing technology for series production, so that further objects also relate to the provision of elements of the floating bodies to be created and their manufacturing forms. The object underlying the invention is achieved according to the invention by the floating body with the features of claim 1. The subclaims represent advantageous embodiments of the invention.

[0008] The basic idea of ​​the invention is to create a float for a floating wind turbine, comprising a plurality of spherical buoyancy bodies with a high packing density. The spheres are particularly hollow spheres, individually transportable, and, if damaged, individually replaceable without having to disassemble neighboring spheres. The required total buoyancy of the float is distributed among a plurality of spheres / buoyancy bodies, so that if one sphere is damaged, the entire structure is not endangered, thus requiring no immediate replacement or repair. The turbine can therefore continue to operate, and there is no loss of energy yield.

[0009] According to the invention, a floating body is proposed with a plurality of balls arranged concentrically around a support, wherein the balls are fastened to the support, at least a first subset of the balls are arranged in at least one first plane and at least a second subset of the balls are arranged in at least one second plane arranged parallel to the first plane, and wherein the balls of the second plane are arranged offset from the balls of the first plane in such a way that the balls of the second plane engage in the spaces between the balls of the first plane.

[0010] It is preferably provided that the balls are identically designed. It is further preferably provided that the number of balls in the first subset and the number of balls in the second subset are identical. It is therefore preferably provided that a first subset of balls in the first plane and a second subset of balls in the second plane are arranged concentrically around the support, wherein the balls in the second plane are rotated around the support relative to the balls in the first plane such that, viewed from above, the sphere centers of the balls in the second plane are positioned centrally on an imaginary circular path between the sphere centers of the balls in the first plane. This means that the angle of rotation between the first and second sphere planes results in an angle of a = 360° / 2x the number of balls per plane. For example, 5 concentrically arranged balls per plane are conceivable, with the planes then rotated by 36° relative to one another.In any case, the distance between the parallel planes is smaller than the diameter of the balls, so that the balls of the second plane engage in the spaces between the balls of the first plane.

[0011] In general, it is intended that the balls are preferably arranged in a ring around the carrier.

[0012] According to a further preferred embodiment, the distance between the spheres arranged in the at least one first plane is smaller than the diameter of these spheres. The distances between the carrier and the spheres, as well as between the spheres themselves, are preferably selected such that the spheres have the highest packing density, taking into account the distances between the spheres within a plane and between the planes.

[0013] A particularly advantageous design with regard to minimal material expenditure is achieved when the balls are designed as hollow spheres. Specifically, the balls are manufactured in one piece without a connecting surface using a rotational molding process, with the balls most preferably being made of a fiber-reinforced thermoplastic.

[0014] Compared to other processes, such as injection molding and blow molding, the rotational molding process has the advantage that stress-free hollow bodies made of fiber-reinforced plastics with suitable wall thicknesses of up to 25 mm can be produced.

[0015] Specifically, tests have demonstrated that hollow spheres made of fiber-reinforced polyethylene with a diameter of 4.2 m and a wall thickness of 15 mm exhibited only minimal deformation under the tested hydraulic static pressures and were able to withstand the resulting material stresses over the long term. Polyethylene also exhibits better abrasion resistance than other thermoplastics, with marine growth and ice formation on the polyethylene spherical shells being less pronounced than with steel and the glass-fiber-reinforced thermosets used in previous floats.As a thermoplastic material, polyethylene is easily recyclable, even with fiber reinforcement, whereby the material expenditure is significantly reduced compared to conventional systems, so that this material is preferred for the production of the floating bodies according to the invention - taking into account the original instability to UV radiation and the additives required thereby.

[0016] The present invention specifically enables the balls to be releasably attached to the carrier independently of one another. Preferably, the attachment of the balls to the carrier or the detachment of the balls from the carrier takes place by means of a movement guided radially with respect to the carrier. For this purpose, a plurality of arms extending radially from the carrier are preferably provided, at each of whose free ends a fastening device for fastening a ball to the arm is provided. Specifically, two arms are each configured for fastening a ball, with the ball contacting the fastening devices of the arms with two surface portions located opposite one another with respect to the center of the ball.

[0017] The fastening devices of the arms and the balls preferably comprise elements of a cooperating plug-in connection. In particular, the fastening devices of the arms comprise radially extending slots designed to accommodate rods or screws arranged on the balls.

[0018] Furthermore, it is preferably provided that the arms arranged adjacently in a plane are each connected to one another by means of a skirt, which is curved to conform to the contour of the sphere attached to the respective arm. These curved skirts are arranged alternately around the support such that adjacent skirts in a plane are curved in opposite directions. The skirts have a beneficial effect on the hydrodynamic properties of the floating body, ensure overall improved stability of the structure, and simultaneously provide protection for the buoyancy bodies designed as spheres.

[0019] It is understood that in addition to the floating body as such, a wind turbine with a floating body designed according to the invention is also claimed.

[0020] As an essential element of the floating body, the invention also consists in a hollow sphere made of a thermoplastic material and formed by means of a rotational melting process for a floating body designed according to the invention, as previously described, wherein the sphere has a connecting means designed to connect the hollow sphere to the support of the floating body, comprising a plate, a ring arranged parallel to the plate, and a plurality of spacers connecting the plate to the ring, wherein the plate is arranged on the outside of the hollow sphere and has at least one means designed to fasten the hollow sphere to the support, and at least the spacers and the ring are molded with the thermoplastic material in a form-fitting manner. On the one hand, the hollow sphere can be designed such that the plate rests on the outside of the sphere wall.Alternatively, the plate can be partially immersed in the sphere wall, i.e., be laterally surrounded by the sphere wall, which creates a positive fit that counteracts transverse forces acting on the plate. The plate is preferably circular and has a diameter identical to that of the ring.

[0021] The thermoplastic material is preferably fiber-reinforced polyethylene with the aforementioned advantages.

[0022] In particular, the means designed to fasten the hollow sphere to the support is a blind hole having an internal thread and designed to receive a screw or a threaded rod.

[0023] Finally, a particularly preferred manufacturing mold for producing the aforementioned hollow sphere is also claimed, in which two mold halves that can be assembled to form a sphere are provided with at least one recess designed to flush receive the plate of the connecting means, wherein the recess has means for fastening the plate within the recess. The recess can have a depth that corresponds to the thickness of the plate, so that the plate rests on the outer side of the spherical wall of the manufactured hollow sphere. Alternatively, the recess can have a depth that is smaller than the thickness of the plate, so that the plate of the manufactured hollow sphere dips into the wall of the hollow sphere and is secured against any transverse forces that occur.

[0024] Preferably, a through hole is provided in the outer wall of the recess, and a screw is provided for fastening the plate within the recess. Insertable into the through hole and threaded into the internal thread of the blind hole. Further preferably, two recesses are provided, each for receiving a connecting means, with each mold half specifically having a recess. The invention is explained in more detail below with reference to a particularly preferred embodiment shown in the accompanying drawings. They show:

[0025] Fig. 1 is a perspective view of a particularly preferred floating wind turbine with floating bodies particularly preferred according to the invention;

[0026] Fig. 2 shows a particularly preferred floating body according to the invention in a perspective view;

[0027] Fig. 3 shows the floating body shown in Fig. 2 in a side view (A) and in a top view (B);

[0028] Fig. 4 shows a particularly preferred carrier of the previously illustrated particularly preferred floating body;

[0029] Fig. 5 shows the carrier from Fig. 4 in a side view (A) and in a top view (B);

[0030] Fig. 6 is a schematic detailed view of the connection between two arms of the support and a ball in a side view (A) and in a plan view (B);

[0031] Fig. 7 shows a connecting means provided on the balls for fastening the balls to the supports in a perspective view (A) and in a sectional view;

[0032] Fig. 8 shows a particularly preferred manufacturing mold for producing the floating body balls with connecting means positioned therein at the beginning of the ball production in a partially sectioned perspective view

[0033] (A) and in a sectional view in the area of ​​a connecting means

[0034] (B); Fig. 9 shows the particularly preferred manufacturing mold from Fig. 8 with a ball manufactured therein after completion of production in a partially sectioned perspective view (A) and in a sectioned view in the region of a connecting means (B);

[0035] Fig. 10 is a partially sectioned view through a ball manufactured using the manufacturing mold from Fig. 8 in a partially sectioned perspective view (A) and in a view sectioned in the region of a connecting means.

[0036] Fig. 1 shows a perspective view of a particularly preferably configured floating offshore wind turbine with floating bodies configured particularly preferably according to the invention. In particular, Fig. 1 shows a floating wind turbine 100 with a Y-shaped floating foundation, which is typical for this type of turbine, wherein a particularly preferably configured floating body 10 according to the invention is arranged at each of the free ends of the Y-shaped foundation structure. The floating body 10 serves not only to generate buoyancy, but is connected and configured to the foundation in such a way that the floating bodies 10 can also be used as anchor points for the guy cables.

[0037] One of these floating bodies 10 is shown in a perspective view in Fig. 2, separate from the wind turbine 100. The preferably configured floating body 10 essentially consists of a centrally arranged support 20, around which a plurality of floating bodies designed as spheres 30 are arranged in concentric circles in a plurality of planes, wherein the spheres 30 are in particular hollow spheres.

[0038] As can be seen from Fig. 3, in which the floating body 10 shown in Fig. 2 is shown in a side view (A) and in a top view (B), a first subset of the balls 30 is arranged in a first plane, and a second subset of the balls 30 is arranged in a second plane parallel to the first plane, wherein the balls 30 of the second plane are offset from the balls 30 of the first plane in such a way that the balls 30 of the second plane engage in the spaces between the balls 30 of the first plane. Due to this configuration, a maximum packing density of the balls 30 arranged in a ring around the carrier 20 is possible. In order to achieve this arrangement with a high packing density, the carrier 20, in particular - as shown in Fig. 4 in a perspective view without balls 30 - can have a central element 22, from which a plurality of arms 26 extend radially.At the free ends of the radially extending arms 26, a fastening device 28 is provided for fastening a ball 30 to the arm 26, wherein two arms 26 are each configured for fastening a ball 30, and the ball 30 contacts the fastening devices 28 of the arms 26 with two surface sections opposite one another with respect to the center of the ball. The arms 26, arranged adjacently in a plane, are each connected to one another by means of an apron 24, which is curved to conform to the contour of the ball 30 attached to the respective arm 26.

[0039] These curved aprons 24 are - as can be seen from Fig. 5 in a side view (A) and in a plan view (B) of the carrier 20 - arranged alternately around the carrier in such a way that adjacent aprons 24 are curved in opposite directions.

[0040] Fig. 6 shows a schematic detailed view of the connection between two arms 26 of the carrier 20 and a ball 30 in a side view (A) and a top view (B). On the one hand, it is clearly visible in Fig. 6 that two arms 26 are each configured to fasten a ball 30, wherein the ball 30 contacts the fastening devices 28 of the arms 26 with two surface portions opposite one another with respect to the center of the ball. On the other hand, it is particularly clear from Fig. 6B that the fastening devices 28 of the arms 26 and the balls 30 have elements of a mutually interacting plug-in connection. In particular, the fastening devices 28 of the arms 26 have radially extending slots configured to receive threaded rods or screws arranged on the balls 30.The balls 30 are secured to the arms 26 by frictional engagement either by means of nuts screwed onto the threaded rods or by tightening the alternatively provided screws.

[0041] This design specifically allows the balls 30 to be positioned independently of each other on the

[0042] Carrier 20 is to be attached to or detached from the carrier 20. In particular, this design makes it possible to attach or detach the balls 30 to the carrier 20 by means of a radially guided movement with respect to the carrier 20.

[0043] To achieve this type of fastening, the present application proposes that the balls 30 be formed as hollow spheres produced by rotational molding. In particular, the balls 30 are produced by rotational molding of a fiber-reinforced thermoplastic.

[0044] The challenge here is to integrate the connecting means 32 into the walls of the balls 30 for fastening to the support 20 and for transmitting forces acting on the balls 30 into the support 20.

[0045] For this purpose, Fig. 7 shows, in isolation, a particularly preferred connecting means 32 provided on the balls 30 for fastening the balls 30 to the supports 20 in a perspective view (A) and a sectional view (B). The connecting means 32 is—as shown below—positively connected to the wall of a ball 30, each ball 30 having two connecting means 32 arranged at positions opposite each other relative to the center of the ball.

[0046] Each connecting means 32 consists of a preferably circular plate 34 and a ring 36 arranged parallel thereto, which is connected to the plate 34 by means of spacers 38. In the plate 34, there are a plurality of blind holes 35, each having an internal thread, which ultimately serve to fasten the balls 30 to the supports 20, but are also used—as shown below—for fastening in the manufacturing mold 100 shown in Fig. 8 and Fig. 9 for manufacturing the balls 30.

[0047] The particularly preferred manufacturing mold 100 for producing the float balls, shown in Fig. 8, shows a ball formed from two half-shells, with a coupling 110 for connection to a rotating device (not shown) that moves the manufacturing mold 100 in a known, predetermined manner during the formation of the ball 30 by the rotational molding process. As a special feature, the half-shells of the manufacturing mold 100 have recesses 120 for receiving the connecting means 32 at two positions opposite the center of the ball. The recesses 120 are dimensioned such that the plate 34 of a connecting means 32 completely occupies the recess 120, with the spacers 38 with the ring 36 pointing in the direction of the center of the ball of the manufacturing mold 100.To secure the connecting means 32 in the recesses 120, the outer wall of the manufacturing mold 100 has a plurality of through holes corresponding to the blind holes 35 of the plate 34, through which the connecting means 32 are secured in the manufacturing mold 100 by means of screws. The through holes of the manufacturing mold 100 are sealed by the plate 34 of the connecting means 32 before the plastic forming the balls 30 is poured into the manufacturing mold 100.

[0048] If the connecting means 32 are fastened in the production mold 100 by means of screws, fiber-reinforced thermoplastic material can preferably be introduced into the production mold 100 as granules or powder and the rotational melting process can be carried out, the state shown in Fig. 9 being reached towards the end of the process.

[0049] In particular, Fig. 9 shows the particularly preferably designed manufacturing mold 100 from Fig. 8 before demolding the ball 30 manufactured in the manufacturing mold 100 in a partially sectioned perspective view (A) and in a sectioned view in the region of a connecting means (B).

[0050] By means of rotation about two mutually perpendicular axes of the production mold 100, the plastic previously introduced into the production mold 100 is applied to the inner wall of the production mold 100 at the appropriate temperature during the rotational melting process and flows around the spacers 36 and the rings 38 of the connecting means 32 fastened in the recesses 120, which are thus introduced into the wall of the balls 30 in a form-fitting manner (see in particular Fig. 9B).

[0051] After cooling the mold 100 and the ball 30 and demolding from the production mold 100 and in particular removing the screws connecting the connecting means 32 to the production mold 100, the ball shown in Fig. 10, manufactured using the production mold from Fig. 8, is obtained, which is shown in a partially sectioned perspective view (A) and in a view sectioned in the region of a connecting means (B). It can be clearly seen that the plastic has flowed around the ring 36 and the spacers 38, wherein the plate 34 connected to the ring 36 by means of the spacers 38 rests flush on the outer side of the ball 30, the surface of the ball 30.

Claims

CLAIMS 1. Floating body (10) with a plurality of balls (30) arranged concentrically around a carrier (20), wherein - the balls (30) are attached to the carrier (20), - at least a first subset of the balls (30) are arranged in at least one first plane and at least a second subset of the balls (30) are arranged in at least one second plane arranged parallel to the first plane, and - the balls (30) of the second level are arranged offset from the balls (30) of the first level such that the balls (30) of the second level engage in the spaces between the balls (30) of the first level.

2. Floating body (10) according to claim 1, characterized in that the number of balls (30) of the first subset and the number of balls (30) of the second subset are identical.

3. Floating body (10) according to one of the preceding claims, characterized in that the balls (30) are arranged in a ring around the carrier (20).

4. Floating body (10) according to one of the preceding claims, characterized in that the distance between the balls (30) in the respective plane is smaller than the diameter of these balls.

5. Floating body (10) according to one of the preceding claims, characterized in that the balls (30) are of identical design.

6. Floating body (10) according to one of the preceding claims, characterized in that the balls (30) have the highest packing density taking into account the distances between the balls (30) within a plane and between the planes.

7. Floating body (10) according to one of the preceding claims, characterized in that the balls (30) are designed as hollow balls.

8. Floating body (10) according to one of the preceding claims, characterized in that the balls (30) are manufactured in one piece by means of rotational melting.

9. Floating body (10) according to one of the preceding claims, characterized in that the balls (30) are made of a fiber-reinforced thermoplastic material.

10. Floating body (10) according to one of the preceding claims, characterized in that the balls (30) are releasably attached to the carrier (20) independently of one another.

11. Floating body (10) according to one of the preceding claims, characterized in that the balls (30) can be fastened to or detached from the carrier (20) by means of a movement guided radially with respect to the carrier (20).

12. Floating body (10) according to one of the preceding claims, characterized by a plurality of arms (26) extending radially from the carrier (20), at the free ends of which a fastening device (28) is provided for fastening a ball (30) to the arm (26).

13. Floating body (10) according to claim 12, characterized in that two arms (26) are each arranged for fastening a ball (30), wherein the ball (30) contacts the fastening devices (28) of the arms (26) with two surface sections opposite one another with respect to the center of the ball.

14. Floating body (10) according to one of claims 12 and 13, characterized in that the fastening devices (28) of the arms (26) and the balls (30) have elements of a cooperating plug connection.

15. Floating body (10) according to claim 14, characterized in that the fastening devices (28) of the arms (26) have radially extending slots which are designed to receive pins or screws (38) arranged on the balls (30).

16. Wind turbine (100) with a floating body (10) according to one of the preceding claims.

17. A hollow sphere (30) formed from a thermoplastic material by means of a rotational melting process for a floating body (10) according to one of claims 1 to 15, characterized by a connecting means (32) designed to connect the hollow sphere (30) to the support (20) of the floating body (10), comprising a plate (34), a ring (36) arranged parallel to the plate (34) and a plurality of spacers (38) connecting the plate (34) to the ring (36), wherein the plate (34) is arranged on the outside of the hollow sphere (30) and has at least one means (35) designed to fasten the hollow sphere (30) to the support (20), and at least the spacers (38) and the ring (36) are molded into the thermoplastic material in a form-fitting manner.

18. Hollow sphere (30) according to claim 17, characterized in that the means designed to fasten the hollow sphere (30) to the support (20) is a blind hole (35) designed to receive a screw or a threaded rod and having an internal thread.

19. Hollow sphere (30) according to one of claims 17 and 18, characterized in that the plate (34) rests on the outer side of the wall of the hollow sphere (30).

20. Manufacturing mold (100) for manufacturing a hollow sphere according to one of claims 17 and 18, characterized by two mold halves which can be assembled to form a sphere and have at least one recess (120) designed to receive the plate (34) of the connecting means (32), wherein the recess (120) has means for fastening the plate (34) within the recess (120).

21. Manufacturing mold (100) according to claim 20, characterized by a through hole provided in the outer wall of the recess (120) and a screw which can be inserted into the through hole and screwed into the internal thread of the blind hole (35) for fastening the plate (34) within the recess (120).

22. Manufacturing mold (100) according to one of claims 20 and 21, characterized in that the depth of the recess (120) corresponds to the thickness of the plate (34).

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