Platform and method for mounting it

Abstract

The invention relates to a platform (10) for temporarily or permanently mounting to an existing tower structure (1) of a wind turbine, comprising: a scaffold (20) for receiving a crane; and jibs (30) for fastening the platform (10) to the tower structure (1).

Description

[0001] Platform and method for its assembly

[0002] The invention relates to a platform for mounting on an existing tower structure of a wind turbine with a platform for receiving a crane, with booms for fastening the platform to the tower structure, and a method for its assembly.

[0003] When erecting wind turbines, the assembly and installation of the rotor blades and turbines represents a major challenge. Several hundred tons of the current turbine power classes of approximately 4 MW must be lifted to heights of more than 90 m, and even more than 130 m in low-wind areas, and held securely in position until the frictional connection to the supporting structure is established.

[0004] This task will become even more challenging in the future, as the trend is towards turbines with a capacity of 6 to 7 MW and these must be installed at hub heights of more than 200 m.

[0005] This is not possible with the crane systems available today, or only with enormous time and financial expenditure. This is further complicated by the fact that the number of such cranes is very limited and their availability is therefore severely restricted. This unavailability can lead to significant delays in project processes and enormous additional costs due to waiting times and thus the loss of feed-in tariffs.

[0006] A concept was developed for erecting platforms for temporary installation on existing wind turbine towers to achieve greater heights, particularly through the use of conventional tower cranes. The use of platforms for temporary installation on existing wind turbine towers is shown as an example in the published patent application CN 114 180 469 A.

[0007] The invention is therefore based on the object of providing a platform with which wind turbines, in particular with large hub heights, can be manufactured economically.

[0008] This object is achieved by a platform having the features of patent claim 1 and by a method having the features of patent claim 10. The first teaching of the invention relates to a platform for mounting on an existing tower structure of a wind turbine with a platform for receiving a crane, with booms for fastening the platform to the tower structure, wherein the booms consist of a built-up steel construction and each boom comprises at least four longitudinal profiles, wherein one longitudinal profile is arranged as the lower longitudinal profile in the lower part of the boom and three longitudinal profiles are arranged as the front longitudinal profile, as the middle longitudinal profile and as the rear longitudinal profile in the upper part of the boom.

[0009] The platform comprises at least two or preferably exactly two booms.

[0010] The invention enables an economical method for erecting a wind turbine, particularly one with a high hub height. Hub height refers to the hub of the wind turbine's rotor above the ground surface (installation site).

[0011] The wind turbine to be constructed therefore comprises a tower structure and a nacelle mounted on the tower structure. The nacelle houses a generator and other mechanical and electrical components. A hub extends outward, on which the rotor blades are mounted.

[0012] The tower structure of the wind turbine can comprise or consist of a steel or concrete construction, or a hybrid structure, i.e. a combination of a steel structure and concrete.

[0013] The tower structure of the wind turbine preferably comprises a lower lattice structure, a transition, and an upper cylinder, wherein the transition connects the upper cylinder to the lattice structure, see, for example, DE 10 2012 106 772 Al, DE 10 2012 112 415 Al, DE 10 2019 218 687 Al, DE 10 2019 218 358 Al, DE 10 2019 219 722 Al. The lattice structure has at least three corner posts, which can be inclined to one another at an angle to the vertical of the lattice structure, at least in sections, in their direction of extension, cross struts, and / or diagonal struts. The corner posts can be inclined to one another in such a way that they can be spaced further apart from one another in the lower or middle section of the lattice structure than in the upper section of the lattice structure.

[0014] The tower structures have at least one thing in common: they are built on one or more local foundations at their lower ends. The longitudinal profiles can consist of profiles with an open or, preferably, closed cross-section.

[0015] The crane to be mounted on the platform is preferably a tower crane, preferably a self-climbing tower crane, which is used to complete the erection of the wind turbine. Since the tower crane on the platform or platform is located very close to the tower structure, the torque acting on the tower crane is reduced, allowing the wind turbines to be erected even at higher wind speeds.

[0016] The steel structure of the assembled booms and the platform are dimensioned accordingly to be able to lift not only the weight of the crane, but also components such as the nacelle, gearbox, rotor blades, etc. The provided platform, which can be mounted temporarily or permanently, with the crane erected on it, takes into account an economical and safe overall concept for the construction of a wind turbine for any hub height. At least the lower part of the tower structure is preferably already sufficiently dimensioned in advance not only to support the loads from the wind, rotor blades, and turbine, but the dimensioning also preferably takes into account the at least temporary installation of the platform and integration of the tower crane.

[0017] Thus, the platform can be attached to the tower structure of a wind turbine for temporary assembly and thus for a limited period of time, in particular for the duration of the construction or completion of the wind turbine. Alternatively, the platform can also remain permanently attached to the tower structure, in particular to provide storage space for additional components, units, systems, containers for spare parts, etc.

[0018] Further advantageous embodiments and developments will become apparent from the following description. One or more features from the claims, the description, and the drawings can be combined with one or more other features therefrom to form further embodiments of the invention. One or more features from the independent claims can also be combined with one or more other features. The longitudinal profiles each comprise a spherical plain bearing at their ends. The spherical plain bearings are preferably manufactured separately and welded to the longitudinal profile.

[0019] The three longitudinal profiles in the upper part of the boom are connected at their lower ends to the upper end of the lower longitudinal profile via the spherical bearings. The three upper longitudinal profiles are thus almost fan-shaped.

[0020] The position information such as top, bottom, front, back, etc. essentially refers to the assembly state, i.e. when the platform is attached to the tower structure, in order to have a clear assignment.

[0021] In the upper part of the boom, two cross sections are arranged as a front cross section and a rear cross section. The cross sections can each comprise a joint bearing at their ends, with the front longitudinal section being connected at the upper end to the front end of the front cross section via the joint bearings, the middle longitudinal section being connected at the upper end to the rear end of the front cross section and the front end of the rear cross section via the joint bearings, and the rear longitudinal section being connected at the upper end to the rear end of the rear cross section.

[0022] Each boom comprises at least three supports, which are intended to hold the platform. At least two of the supports comprise a pivot bearing, wherein the first or front support is connected via the pivot bearing to the pivot bearings of the upper end of the front longitudinal profile and the front end of the front transverse profile, and the middle or second support is connected via the pivot bearing to the pivot bearings of the upper end of the middle longitudinal profile, the rear end of the front transverse profile, and the front end of the rear transverse profile. The front and middle supports can preferably be identical. The rear or third support can be welded to the rear end of the rear cross member, in particular above or onto a bracket.

[0023] The boom can be attached to an existing tower structure via the spherical bearing at the lower end of the lower longitudinal beam and the spherical bearing at the upper end of the rear longitudinal profile. Therefore, two mounting positions per boom are sufficient to securely and stably attach the platform to the existing tower structure for the period required for the erection or completion of the wind turbine.

[0024] The platform consists of a built-up steel structure comprising at least three longitudinal profiles, at least two transverse profiles, and at least one locking plate connected to and on the profiles. At least one reinforcement plate is arranged locally on the at least one locking plate. If there are several reinforcement plates, for example, four or more, these can in turn serve as supports for the crane to be erected.

[0025] According to a second teaching, the invention relates to a method for mounting a platform on an existing tower structure of a wind turbine, with a platform for receiving a crane, with booms for fastening the platform to the tower structure, wherein first the booms of the platform are fastened to the tower structure and only then is the platform stage connected to or with the booms.

[0026] This can be a temporary or permanent installation.

[0027] The boom is lifted by a crane using a cable hoist. The cable hoist comprises a main strand, which at its lower end is divided into at least three sub-strands with different sub-strand lengths. The boom is connected to the ends of the sub-strands at three defined lifting positions. The sub-strand lengths are dimensioned such that the boom, in a suspended position prior to being attached to the tower structure, assumes an orientation that essentially corresponds to the attachment position. This has the advantage that simple attachment can be achieved without complex alignment in the suspended position.

[0028] The erection or assembly of a subsection, in particular the lower part and optionally the middle part of a tower structure, is carried out using a crane, in particular a standard (mobile) crane, which can preferably have a lifting capacity of at least 50 t and a lifting height of up to 100 m or more. This crane is also used for the temporary or permanent assembly of the platform and the lifting of the preferably tower crane onto the platform. During the erection of the lower and optionally middle part of the tower structure, attachment points for attaching the platform or the boom at defined positions are or will be integrated, for example in the form of spherical bearings, which (can) remain on the tower structure, for example as a welded construction.

[0029] A further logistical advantage is that an entire wind farm can be constructed, preferably with a single platform and a tower crane. After the wind farm is completed, at least the platform, or parts such as the boom and platform, can remain in the wind farm or be stored. This makes the platform immediately available for repairs, such as replacing rotor blades, gearboxes, and / or turbines, as well as for maintenance and repair work, minimizing downtime and thus contributing to cost-effectiveness. This allows for either temporary assembly of a platform or permanent installation, with a separate platform available for each wind turbine.

[0030] Depending on the design of the wind turbine and the hub height, the platform can be attached to the tower structure at a height between 70 and 210 m, in particular between 80 and 200 m, preferably between 90 and 180 m, and most preferably between 100 and 150 m. The height refers to the distance between the ground and the platform's access area. This height increases the tower crane's lifting height.

[0031] Therefore, the use of a platform according to the invention for permanent installation on the tower structure can also be provided, which can preferably enable the accommodation or storage of further components, units, systems, containers for spare parts storage, etc.

[0032] The invention is explained in more detail below with reference to the drawings. Identical parts are provided with the same reference numerals. In detail:

[0033] Fig. 1 is a perspective view of a platform in the attached state according to a first embodiment,

[0034] Fig. 2 is a perspective view of a boom in a suspended state,

[0035] Fig. 3 is a schematic, perspective and enlarged partial view of a connection point in Fig. 2, Fig. 4 is a side view of a platform in the attached state according to a second embodiment of the invention and

[0036] Fig. 5 a finite element plot of an exemplary deformation state from the isometry.

[0037] Figure 1 shows a perspective CAD representation of a platform (10) in the attached state according to a first exemplary embodiment. The tower structure (1) can be designed as a lattice structure in the lower part of a wind turbine (not shown) that is yet to be erected or completed, see, for example, DE 10 2019 219 722 A1. The lattice structure is erected, for example, using a mobile crane (not shown). In addition to the lattice structure, a transition, which connects an upper cylinder of the tower structure (1) that is yet to be constructed, can also be lifted by means of a mobile crane (not shown), which is mounted and attached to the lattice structure. Attachment points (2) for attaching the platform (10) at defined positions, for example in the form of spherical bearings, are integrated on the tower structure (1) or on the lattice structure.

[0038] The platform (10) for temporary or permanent installation on an existing tower structure (1) of a wind turbine comprises a platform (20) for receiving a crane, preferably a self-climbing tower crane, and booms (30) for fastening the platform (10) to the tower structure (1). The booms (30) consist of a built-up steel construction, and each boom (30) comprises at least four longitudinal profiles (31-34), with one longitudinal profile being arranged as the lower longitudinal profile (34) in the lower part of the boom (30), and three longitudinal profiles being arranged as the front longitudinal profile (33), as the middle longitudinal profile (32), and as the rear longitudinal profile (31) in the upper part of the boom (30). The longitudinal profiles (31-34) each comprise a spherical bearing (31.11-34.21) at their ends (31.1-34.1, 31.2-34.2). The three longitudinal profiles (31-33) in the upper part of the boom (30) are connected at their lower end (31.1-33.1) to the upper end (34.2) of the lower longitudinal profile (34) via the spherical bearings (31.11,32.11,33.11,34,21). Bolts or other known fasteners are suitable for joining.

[0039] In the upper part of the boom (30), two cross profiles are arranged as a front cross profile (35) and a rear cross profile (36), which can each comprise a spherical bearing (35.11-36.11) at their ends (35.1, 36.1, 35.2). The front longitudinal profile (33) is connected at the upper end (33.2) to the front end (35.1) of the front cross profile (35) via the spherical bearings (33.21, 35.11). The middle longitudinal profile (32) at the upper end (32.2) is connected to the rear end (35.2) of the front cross profile (35) and the front end (36.1) of the rear cross profile (36) via the spherical bearings (32.21, 35.21, 36.11). The rear longitudinal profile (31) is connected at the upper end (31.2) to the rear end (36.2) of the rear transverse profile (36). Each boom (30) comprises at least three supports (37, 38) which are provided for receiving the platform (20). Two of the supports (37) comprise a pivot bearing (37.1), with the front support (37) being connected via the pivot bearing (37.1) are connected to the spherical bearings (33.21, 35.11) and the middle support (37) is connected to the spherical bearings (32.21, 35.21, 36.11) via the spherical bearing (37.1).

[0040] The boom (30) is rigid and therefore consists of a large number of interconnected or welded steel components.

[0041] The platform (20) also consists of a built-up steel structure, comprising at least three longitudinal profiles (21), at least two transverse profiles (22), and at least one locking plate (23) mounted on and connected to the profiles (21, 22). The locking plate (23) can be composed of several individual locking plates (23), particularly due to its large surface area. At least one reinforcement plate (24) can be arranged locally on the at least one locking plate (23); in this example, there are six reinforcement plates (24).

[0042] Figure 2 shows a boom (30) in a suspended state. The method for temporarily or permanently mounting a platform (10) on an existing tower structure (1) of a wind turbine provides that the booms (30) of the platform (10) are first attached to the tower structure (1) and only then is the platform (20) of the platform (10) connected to or with the booms (30). The platform (20) and boom (30) are thus detachably connected to one another.The boom (30) is lifted with a cable pull (100) by means of a crane (not shown), in particular a mobile crane, in such a way that the cable pull (100) comprises a main strand (101) which is divided at its lower end into at least three sub-strands (102-104) with different sub-strand lengths and the boom (30) is connected to the ends of the sub-strands (102-104) at three defined lifting positions (40). The sub-strand lengths are dimensioned such that the boom (30), in the suspended state before being attached to the tower structure (1), assumes an orientation which essentially corresponds to the attachment position. The platform (10) is attached to the tower structure (1) at a height (H) of between 70 and 210 m. Depending on the technical requirements of the turbine manufacturer, the exemplary lattice structure can have an equilateral triangle as its base area with a side length at the ground between 20 and 30 m.This design allows large bending moments to be transferred into the ground. In conventional tower cranes, this (lack of) lever arm can be compensated for by appropriately high counterweights. The lattice structure is dimensioned to support not only the loads from the wind, rotor blades, and turbine, but also a platform (10) with a conventional, self-climbing tower crane mounted on it.

[0043] After the platform (10) has been mounted on the tower structure (1), a first subassembly of a pre-assembled tower crane is lifted onto the platform (10) or onto the platform (20) of the platform (30) using the mobile crane (not shown) and preferably secured using screw connections. The further construction of the overall structure or the completion of the wind turbine is then carried out with the support of the tower crane mounted on the platform (10). As the height of the tower structure (1) increases, the height of the tower crane is successively increased using additional segments, so that by inserting further intermediate elements, the mast of the tower crane can climb, thus preferably always working at the optimal height (cf. also DE 10 2019 219 722 A1, see Figure 3).If necessary, the platform (10) can generally be stiffened and / or secured by additional ropes (39), which can be attached to the stage (20) and to the tower structure (1).

[0044] Once the tower crane has been assembled, it can be used to install the further, or upper, section of the wind turbine tower structure, as well as the nacelle and rotor blades, thus completing the wind turbine (not shown). A key advantage of this method is that the individual components and parts are easy to transport and require little space for assembly. This concept enables wind turbines to be erected quickly and safely with significantly improved scheduling. Hub heights of over 200 m can be achieved using this technology. The self-climbing tower crane can obtain sufficient stability by attaching additional support arms to the existing tower structure (1), which it can use to brace itself (see also DE 10 2019 219 722 Al).After the final assembly or installation of the wind turbine, the tower crane and, if not intended for permanent use, the platform (10) can be dismantled in reverse order, allowing another wind turbine to be erected and installed. A further logistical advantage is that an entire wind farm can be constructed using a single crane and, for example, a single platform (10). After completion, the crane and platform (10) can remain in the wind farm or be stored. This makes the system immediately available for repairs, such as replacing rotor blades, gearboxes, and turbines, as well as for maintenance and servicing, which minimizes turbine downtime and can therefore significantly contribute to economic efficiency.

[0045] Alternatively, a platform (10) for permanent installation can be provided for each wind turbine.

[0046] The tower structure (1) of a wind turbine not shown is preferably designed for onshore use.

[0047] According to a second embodiment, the application or use of the previously described platform (10) is also possible for tower structures (1) with a circular or polygonal cross-section made of steel or concrete, see Figure 4.

[0048] Figure 5 shows deformations and their progressions, simulated using the FE solver MSC nastran, on a platform (10), with the largest deformations occurring on the stage (20) in an area located on the side facing away from the tower structure (1).

[0049] The features described can all be combined with each other, as far as technically possible.

Claims

Patent claims 1. Platform (10) for mounting on an existing tower structure (1) of a wind turbine, with a platform (20) for receiving a crane, with booms (30) for fastening the platform (10) to the tower structure (1), characterized in that the booms (30) consist of a built-up steel construction and each boom (30) comprises at least four longitudinal profiles (31-34), wherein one longitudinal profile is arranged as the lower longitudinal profile (34) in the lower part of the boom (30) and three longitudinal profiles are arranged as the front longitudinal profile (33), as the middle longitudinal profile (32) and as the rear longitudinal profile (31) in the upper part of the boom (30).

2. Platform according to claim 1, wherein the longitudinal profiles (31-34) each comprise a joint bearing (31.11-34.21) at their ends (31.1-34.1, 31.2-34.2).

3. Platform according to one of the preceding claims, wherein the three longitudinal profiles (31-33) in the upper part of the boom (30) are connected together at their lower end (31.1-33.1) to the upper end (34.2) of the lower longitudinal profile (34) via the articulated bearings (31.11, 32.11, 33.11, 34.21).

4. Platform according to one of the preceding claims, wherein in the upper part of the boom (30) two transverse profiles are arranged as a front transverse profile (35) and as a rear transverse profile (36), which can each comprise a joint bearing (35.11-36.11) at their ends (35.1, 36.1, 35.2), wherein the front longitudinal profile (33) is connected at the upper end (33.2) to the front end (35.1) of the front transverse profile (35) via the joint bearings (33.21, 35.11), wherein the middle longitudinal profile (32) is connected at the upper end (32.2) to the rear end (35.2) of the front transverse profile (35) and the front end (36.1) of the rear transverse profile (36) via the joint bearings (32.21, 35.21, 36.11), and wherein the rear longitudinal profile (31) at the upper end (31.2) is connected to the rear end (36.2) of the rear cross profile (36).

5. Platform according to one of the preceding claims, wherein each boom (30) comprises at least three supports (37, 38) which are provided for receiving the platform (20).

6. Platform according to claim 5, wherein two of the supports (37) comprise a joint bearing (37.1), wherein the front support (37) is connected to the joint bearings (33.21, 35.11) via the joint bearing (37.1) and the middle support (37) is connected to the joint bearings (32.21, 35.21, 36.11) via the joint bearing (37.1).

7. Platform according to one of the preceding claims, wherein the boom (30) can be attached to an existing tower structure (1) via the pivot bearing (34.11) at the lower end of the lower longitudinal member (34) and via the pivot bearing (31.21) at the upper end of the rear longitudinal profile (31).

8. Platform according to one of the preceding claims, wherein the stage (20) consists of a built steel structure comprising at least three longitudinal profiles (21), at least two transverse profiles (22) and at least one locking plate (23) on the profiles (21, 22) and connected thereto.

9. Platform according to claim 8, wherein at least one reinforcing plate (24) is arranged locally on the at least one locking plate (23).

10. Method for mounting a platform (10) on an existing tower structure (1) of a wind turbine, with a stage (20) for receiving a crane, with booms (30) for fastening the platform (10) to the tower structure (1), in particular a platform (10) according to one of the preceding claims, characterized in that firstly the booms (30) of the platform (10) are fastened to the tower structure (1) and only then is the stage (20) of the platform (10) connected to or with the booms (30).

11. The method according to claim 10, wherein the boom (30) is lifted with a cable pull (100) by means of a crane, such that the cable pull (100) comprises a main strand (101) which is divided at its lower end into at least three partial strands (102-104) with different partial strand lengths and the boom (30) is connected to the ends of the partial strands (102-104) at three defined lifting positions (40), wherein the partial strand lengths are dimensioned such that the boom (30) in the suspended state before being fastened to the tower structure (1) assumes an orientation which substantially corresponds to the fastening position.

12. Method according to one of claims 10 or 11, wherein the platform (10) is attached to the tower structure (1) at a height (H) between 70 and 210 m.

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