Ring and transition piece, in particular for a wind turbine, tower for a wind turbine and wind turbine

Abstract

The invention relates to a ring (1), in particular for a wind turbine, comprising: a lower contact surface (2) which can be placed on the upper end of a reinforced concrete ring or on a steel plate, an upper contact surface (3) on which a transition piece (13) or a tubular steel tower can be placed, and an outer contour (5) with a lower outer section (6), which is concave and extends from the lower contact surface (2) in the direction of the upper contact surface (3), while reducing its diameter, and an upper outer section (7), which adjoins the lower outer section (6) and has a substantially constant diameter. The invention also relates to an arrangement (12) having a ring (1) and a transition piece (13), and to a tower (17) and a wind turbine.

Description

[0001] Ring and transition piece, in particular for a wind turbine, tower for a wind turbine and wind turbine

[0002] The invention relates to a ring and a transition piece for a tower, in particular a wind turbine.

[0003] An established design for wind turbines involves a two-part tower structure. The lower section is a reinforced concrete tower mounted on a foundation. The reinforced concrete tower consists of stacked reinforced concrete rings. In the lower section of the reinforced concrete tower, a reinforced concrete ring can also be composed of several reinforced concrete ring segments.

[0004] The upper part of the wind turbine consists of a tubular steel tower positioned on top of the reinforced concrete tower. The tubular steel tower supports a turbine. A transition piece is typically located between the reinforced concrete tower and the tubular steel tower, which serves two functions. On the one hand, the ends of tendons are attached to the transition piece, the other ends of which are anchored to the foundation. The tendons brace the reinforced concrete tower. The transition piece also serves as a support for the tubular steel tower. Such transition pieces have generally proven their worth.

[0005] DE 102011 001 250 A1 describes a T-shaped steel component suitable for forming the transition between the lower prestressed concrete section of a tower and the steel tower section. The tendons of the lower prestressed concrete tower section are inserted, anchored, and prestressed through recesses arranged centrally in a T-shaped cross-section. The component is thus anchored without additional anchoring elements and without additional loads from eccentrically acting forces.

[0006] Currently, wind turbines are being developed that are designed for particularly high power outputs. This results in larger rotor diameters and greater hub heights. Furthermore, the loads acting on the transition piece are also increasing, which can cause high local compressive stresses on the top surface of the reinforced concrete tower's top ring. Therefore, there is a need for a solution that prevents damage and premature fatigue of the top ring.

[0007] To solve this problem, a ring having the features of claim 1 is provided.

[0008] The ring according to the invention comprises a lower contact surface which can be placed on the upper end of a reinforced concrete ring or on a steel plate, an upper contact surface onto which a transition piece or a steel tube tower can be placed, and an outer contour with a lower outer section which is concave and extends from the lower contact surface with a reduction in its diameter towards the upper contact surface, and with an upper outer section which adjoins the lower outer section and has a substantially constant diameter.

[0009] The invention is based on the finding that the ring according to the invention can achieve a homogenization of the stress distribution on the upper surface of the uppermost reinforced concrete ring. The stress distribution is homogenized both tangentially and radially, thereby counteracting premature fatigue of the reinforced concrete ring. This makes it possible to build wind turbines designed for higher power outputs.

[0010] The ring according to the invention is placed on the top ring of the reinforced concrete tower. The through openings in the ring are preferably used to anchor tendons that extend in the longitudinal direction of the reinforced concrete tower and are anchored at their other end to a foundation.

[0011] The lower outer section of the outer contour is concave, so that the diameter of the ring decreases from the lower contact surface until it merges into the upper outer section with a constant diameter. This shape saves material and also results in the desired homogenization of the stress distribution, preventing stress peaks.

[0012] The ring can be provided with a plurality of circumferentially arranged through-holes. Tendons can be anchored to the through-holes. The reinforced concrete rings are braced together by means of the tendons, which extend from the ring to a foundation.

[0013] In the ring according to the invention, it is preferred that the lower outer section and the upper outer section of the outer contour seamlessly merge into one another. This design also contributes to avoiding stress peaks and enables a uniform transfer of forces from a tubular steel tower to the reinforced concrete tower.

[0014] The ring according to the invention is preferably manufactured as a cast component, in particular from cast steel or cast iron. The ring is preferably manufactured as a monolithic component, in particular using a casting process. With this design, the ring can reliably absorb and transmit the loads that occur.

[0015] A preferred development of the invention provides that the upper contact surface and the lower contact surface are machined and preferably arranged parallel to each other. After the ring is cast, it is machined on its opposite contact surfaces, thereby ensuring exact parallelism. The tower for a wind turbine comprising the ring thus has a precisely aligned upper horizontal contact surface onto which a transition piece or a tubular steel tower can be mounted.

[0016] It is particularly preferred that the ring has an inner contour with a lower inner section which is convex and extends from the lower contact surface while reducing its diameter in the direction of the upper contact surface, as well as with a central inner section which adjoins the lower inner section and has a substantially constant diameter, as well as with an upper inner section which is convex, adjoins the central inner section and extends to the upper contact surface.

[0017] This special design results in further material savings. Uniform force transmission and thus even stress distribution are achieved both tangentially and radially. Premature fatigue and damage to the reinforced concrete ring are avoided.

[0018] Similar to the outer contour, it is also preferred for the inner contour that the lower inner section and the middle inner section as well as the middle inner section and the upper inner section each merge smoothly into one another in order to achieve a smooth flow of force.

[0019] Preferably, the ring is manufactured as a monolithic component from spheroidal graphite cast iron and / or with inclusion of spheroidal graphite. Such a ring can exhibit improved elongation at break and / or notched impact toughness, particularly for use at low temperatures. In a preferred embodiment, the ring is made of unalloyed or alloyed spheroidal graphite cast iron, in particular in accordance with the German industrial standard DIN EN 1563 - 2019. Cast irons in this material group can also be referred to as "bainitic-austenitic spheroidal graphite cast iron," "bainitic spheroidal graphite cast iron," "intermediate-tempered spheroidal graphite cast iron," and / or "austempered ductile iron (ADI)."

[0020] In a preferred embodiment of the manufacturing process, after casting the ring, a heat treatment takes place, in particular annealing at a low temperature, for example between 675°C and 725°C, preferably at approximately 700°C, followed by cooling, in particular at a rate of approximately 50°C per hour. In this way, the proportion of eutectoid iron carbide can be reduced, particularly in a ring made of spheroidal graphite cast iron, in order, for example, to achieve the desired notched impact toughness at low temperatures. The ring serves in particular to transfer the prestressing forces and operating loads to the lower part of the reinforced concrete tower, in particular a prestressed concrete tower. The ring is preferably arranged as an additional "pressure stamp" between an upper tower section, in particular designed as a tubular steel tower with thinner walls, and the lower part of the prestressed concrete tower with thicker walls.With the help of the ring, the stress distribution towards the uppermost reinforced concrete ring can be smoothed. In an advantageous embodiment, a stress gradient caused by the prestressing forces and operating loads can be reduced by means of the ring. The load introduction can be mediated in particular via an L-shaped lower flange of the transition piece. To compensate for an eccentric load introduction into the lower tower section, the upper contact surface of the ring is offset radially inward with respect to the lower contact surface of the ring. Suitable load distribution can be provided in particular by a ring with an outer contour having a corresponding concavity and represent an improved loading situation for the concrete components of the lower tower section. As a load-bearing component, the ring is prestressed and loaded in particular by the tensioning system.

[0021] The invention also relates to an arrangement comprising a ring of the type described and a tubular transition piece, particularly formed integrally with the ring, which has a flange on its upper side for attaching a steel tower. The ring and the transition piece thus form a single unit that can be placed on the reinforced concrete tower. The steel tower can then be placed on the arrangement.

[0022] In this context, according to one possible embodiment, it is preferred that the ring and the transition piece of the arrangement according to the invention be welded together. This offers the advantage that the welding process can be carried out before the arrangement is placed on the reinforced concrete tower.

[0023] The invention also relates to a tower for a wind turbine, comprising a foundation, a lower tower section comprising reinforced concrete ring segments and / or reinforced concrete rings, a ring of the type described arranged on top of the lower tower section, and a tubular transition piece arranged on the ring and preferably welded to the ring. The lower tower section is braced by means of tendons that are supported on the foundation on one side and on the ring on the other. The ring according to the invention enables the tower according to the invention to be used even in wind turbines with high power outputs and large hub heights.Preferably, in the tower according to the invention, the through openings in the ring are arranged either in such a way that the tendons run within the reinforced concrete ring segments and / or the reinforced concrete rings of the lower tower section, or alternatively, they can also run exposed in the interior of the lower tower section.

[0024] Finally, the invention relates to a wind turbine having a tower of the type described, which has a lower tower section, and an upper tower section mounted thereon, which is designed as a tubular steel tower and carries a turbine.

[0025] The invention also relates to a transition piece for a tower, in particular of a wind turbine. The transition piece comprises, in particular, a lower annular contact surface with a plurality of through-openings arranged in the circumferential direction, an upper annular contact surface with a plurality of through-openings arranged in the circumferential direction, a central section which extends essentially perpendicular to the contact surfaces in the axial direction, with a lateral surface surrounding a free space, on one axial side of which the lower annular contact surface is arranged and on the opposite axial side of which the upper annular contact surface is arranged. The transition piece connects the lower part, in particular of a hybrid tower, to the tubular steel tower or another tower placed thereon. The lower part of a hybrid tower is designed as a prestressed concrete tower. It has tendons, in particular strands.The tendons are anchored at their ends, i.e., at one end to the foundation and at the other end to the transition piece located on the top ring of the prestressed concrete tower. Tensioning the tendons applies compressive stress to the rings, providing the prestressed concrete tower with the required stability. The upper end of a tendon passes through another opening at the lower annular contact surface of the transition piece.

[0026] Preferably, through-openings, bores, recesses or the like are also provided on the upper annular contact surface of the transition piece, which serve to fasten the upper part of the hybrid tower, in particular the steel tube tower.

[0027] A tubular transition piece composed of several segments arranged side by side in the circumferential direction is particularly easy to transport. This is particularly advantageous in the context of wind turbines.

[0028] In the development of wind turbines, there is a trend toward ever-increasing power outputs. This increases both the rotor diameter and the tower height, and inevitably also the diameter of the transition piece. Above a certain size, transporting a transition piece to the planned installation site becomes complex, as special transport is required. Transporting such large objects is often also complicated by traffic signs, bridges, branches, etc. Even if the turbine is segmented into two halves, special transport is no longer necessary. This results in cost advantages and greater flexibility in transporting the turbine from the production site to the construction site.

[0029] Preferably, the transition piece is composed of n segments, where n is a number between 2 and 12.

[0030] Preferably, several or all segments are the same size.

[0031] Preferably, a segment has circumferential coupling surfaces extending radially and at least approximately parallel to the axial direction, which form flanges for connecting adjacent segments.

[0032] Preferably, the flanges of adjacent segments have through openings, in particular bores or recesses, located opposite one another.

[0033] Preferably, the contact surfaces and the middle section are made of steel and welded together.

[0034] Preferably, the through openings of the lower and upper annular contact surfaces are offset radially inwards relative to the lateral surface of the central section.

[0035] Preferably, the transition piece is cylindrical or conical in shape.

[0036] In addition, the invention relates to a tower for a wind turbine, with a foundation, a lower tower section having reinforced concrete ring segments and / or reinforced concrete rings, optionally with a ring arranged on the upper side of the lower tower section, in particular the ring already described above, and a transition piece of the type described, which is arranged on the tower section or optionally on the ring, wherein the lower tower section is braced by means of tendons which are supported on the one hand on the foundation and on the other hand on the transition piece.

[0037] In the tower according to the invention, the ring arranged on the lower tower section can be designed as a steel ring, a reinforced concrete ring or a cast ring.

[0038] The ring is optional, meaning a tower can be constructed either with or without a ring. However, it is preferred that the tower have such a ring, which contributes to the equalization of the acting loads. Furthermore, the invention relates to a wind turbine with a tower of the type described, having a lower tower section, and an upper tower section mounted thereon, designed as a tubular steel tower and supporting a turbine.

[0039] The invention is explained below using exemplary embodiments with reference to the drawings. The drawings are schematic representations and show:

[0040] Fig. 1 is a perspective view of a ring according to an embodiment of the invention;

[0041] Fig. 2 is a plan view of the ring of Fig. 1;

[0042] Fig. 3 is a sectional view along the line III-III of Fig. 2;

[0043] Fig. 4 is an enlarged view of the cross-section of the ring shown in Fig. 3;

[0044] Fig. 5 shows an arrangement with a ring and a transition piece according to an embodiment of the invention;

[0045] Fig. 6 shows a tower according to an embodiment of the invention;

[0046] Fig.7 the arrangement of Fig. 5 in a perspective view;

[0047] Fig. 8 is a sectional view of a segmented transition piece for a tower according to a first embodiment;

[0048] Fig. 9 shows the transition piece of Fig. 8 in a perspective view;

[0049] Fig. 10 shows a single segment of the transition piece of Fig. 8 in a perspective view;

[0050] Fig. 11 is a sectional view of a segmented transition piece for a tower according to a second embodiment;

[0051] Fig. 12 the transition piece of Fig. 11 in a perspective view;

[0052] Fig. 13 shows a single segment of the transition piece of Fig. 11 in a perspective view;

[0053] Fig. 14 is a sectional view of a segmented transition piece for a tower according to a third embodiment;

[0054] Fig. 15 the transition piece of Fig. 14 in a perspective view;

[0055] Fig. 16 shows a single segment of the transition piece of Fig. 14 in a perspective view;

[0056] Fig. 17 shows a coupling surface of a segment of a transition piece in detail. Fig. 18 shows a ring according to a further embodiment of the invention in a perspective view.

[0057] Fig. 19 the ring of Fig. 18 in a cross-sectional view.

[0058] Identical or corresponding elements are provided with the same reference numerals in all drawings.

[0059] The ring 1 shown in Figures 1 to 4, 18 and 19 is made of cast steel or iron and comprises a lower contact surface 2 and an upper contact surface 3, which are produced from the raw casting by machining such as milling or grinding. Both contact surfaces 2, 3 are aligned with each other with high precision. The ring 1 comprises a plurality of through-openings 4 arranged in the circumferential direction, which are cylindrical in the illustrated embodiment. However, other designs are also possible in which the through-openings 4 are conical. In the assembled state, the through-openings 4 are penetrated by tendons 15, with which a reinforced concrete ring 192 is braced.

[0060] The ring 1 has an outer contour 5 with a lower outer section 6 that is concave and extends upwards from the lower contact surface 2, with the diameter of the lower outer section 6 decreasing. Adjoining the lower outer section 6 is an upper outer section 7, which in this embodiment has a constant diameter. The upper outer section 7 extends up to the upper contact surface 3. The lower outer section 6 and the upper outer section 7 merge seamlessly into one another.

[0061] The ring 1 has an inner contour 8 which has a lower, convexly shaped inner section 9. The lower inner section 9 extends upwards from the lower contact surface 2, reducing its diameter, as shown in Fig. 4. This is followed by a central inner section 10 which has an at least approximately constant diameter. An upper inner section 11 extends up to the upper contact surface 3. The lower inner section 9, the central inner section 10 and the upper inner section 11 each merge continuously into one another. The central inner section 10 forms a constriction of the ring 1, thereby saving material and thus mass and costs.

[0062] Fig. 5 is a sectional view of an assembly 12 comprising the ring 1 and a tubular transition piece 13 formed integrally therewith. The ring 1 and the transition piece 13 are welded together. At the upper end of the transition piece 13 is a flange 14, which serves to attach a tubular steel tower (not shown). The through-openings 4 of the ring 1 are penetrated by tendons 15, which are braced relative to the ring 1 of the assembly 12 by means of anchors 16. The other, lower end of the tendons 15 is anchored to a foundation.

[0063] The transition piece 13 has a lower flange 141 with additional through-openings 137 arranged coaxially with the through-openings 4 of the ring 1. The tendons 15 extend through the through-openings 4 of the ring 1 and the additional through-openings 137. The anchors 15 fasten the tendons 15 to an upper side of the lower flange 141.

[0064] Finally, Fig. 6 shows a tower 17 for a wind turbine, with a foundation 18 and a lower tower section 19 comprising reinforced concrete ring segments 191 and reinforced concrete rings 192. The assembly 12 with the ring 1 and the transition piece 13 is arranged on top of the lower tower section 19. An upper tower section 20, which is designed as a tubular steel tower and supports a turbine, can be placed on the transition piece 13.

[0065] Figure 5 is a sectional view of the transition piece 13 as a component of the tower 13, wherein the transition piece 13 is arranged on a cast ring, in particular the ring 1, which in turn is arranged on the uppermost ring of reinforced concrete ring segments 191. Tendons 15 are supported on a lower annular contact surface 135 of the transition piece 13 and penetrate its further through-openings 137. A steel tube tower is mounted on an upper annular contact surface 136 of the transition piece 13.

[0066] As shown in Figure 5, the lower annular contact surface 135 can be provided by the lower flange 141 and the upper annular contact surface 136 can be provided by an upper flange 14 of the transition piece 13. The lower and / or upper flange 14, 141 can in particular be welded to a central portion 133 of the transition piece 13.

[0067] The tubular transition piece 13 is, for example, formed in one piece, essentially as a hollow cylinder. The exemplary embodiment in Fig. 5 illustrates a segmented structure of the tubular transition piece 13, wherein a full-circumferential section of the transition piece 13 is formed by a plurality of segments 131 arranged in the circumferential direction.

[0068] Figure 7 is a perspective view of the transition piece 13 shown in Figure 5. Figures 8, 9, and 10 show an embodiment with a two-part transition piece 13, wherein Figure 8 is a plan view and Figure 9 is a perspective view. Figure 10 shows a segment 131 of the split transition piece 13. Figures 11, 12, and 13 show an embodiment with a three-part transition piece 13, wherein Figure 11 is a plan view and Figure 12 is a perspective view. Figure 13 shows a segment 131 of the split transition piece 13.

[0069] Figures 14, 15, and 16 show an embodiment with a four-part transition piece 13, with Figure 14 being a plan view and Figure 15 being a perspective view. Figure 16 shows a segment 131 of the split transition piece 13.

[0070] Figure 12 shows a coupling surface 132 that extends radially and parallel to the axial direction on a segment 131 of the transition piece 13. The coupling surface 132 forms a flange for connecting to an adjacent segment of the transition piece 13. For this purpose, the coupling surface 132 has a plurality of bores 134 for receiving suitable fastening means, such as bolts or the like. The coupling surfaces 132 are connected, for example, by welding to the central section 133 of a segment 131. The tubular transition piece 13 is provided, as shown in Figs. 8 to 16, by a plurality of segments 131 that are positioned and fixed relative to one another in the circumferential direction. The bores 134 in the coupling surfaces 132 that abut one another at the end can form continuous passages, in particular for receiving suitable fastening means.

[0071] To accommodate the clamping means 15, the passages 14 in the ring 1 and the further passages 137 in the transition piece 13 are preferably aligned coaxially with each other.

[0072] Figures 18 and 19 illustrate a further embodiment of the ring 1, which is made of cast steel or cast iron, preferably of cast iron with spheroidal graphite. The outer contour 5 of the ring 1 has the lower outer section 6, which is concave and extends upwards from the lower contact surface 2, reducing its diameter. In the adjoining, upper outer section 7, the outer diameter of the ring 1 changes only insignificantly, with the outer sections 6, 7 merging seamlessly into one another. The inner contour 8 of the ring 1 has the lower, convexly shaped inner section 9, the middle inner section 10, and the upper inner section 11, which is also convex. Compared to the embodiments illustrated in particular with reference to Figures 1 to 17, the upper inner section 11 protrudes further in the radial direction into the tower interior than the lower inner section 9.In other words, the upper inner section 11 forms a projection relative to the lower inner section 9 and relative to an inner radius of the lower tower section 19, so that the upper contact surface 3 is arranged radially inwardly offset relative to the lower contact surface 2. With such a ring 1, an eccentric load introduction, which is caused, for example, by the operating loads of the upper tower section 20 and / or other tower structures and is conveyed in particular via the lower flange 141 of the transition piece 13 into the upper contact surface 3 of the ring 1, can be compensated. The dimensioning of the inner sections 8, 10, 11 and / or the radial offset of the contact surfaces 2, 3 of the ring 1 relative to one another can be designed differently, in particular depending on the magnitude of the loads to be introduced into the lower tower section 19.

[0073] It is understood that the description, particularly with reference to the figures, serves to illustrate the invention and is not to be construed as limiting. Deviations from this are possible and intended, as long as they are within the scope of protection defined by the following claims.

[0074] List of reference symbols

[0075] 1 ring

[0076] 2 lower contact surface

[0077] 3 upper contact surface

[0078] 4 passage opening

[0079] 5 Outer contour

[0080] 6 lower outer section

[0081] 7 upper outer section

[0082] 8 Inner contour

[0083] 9 lower inner section

[0084] 10 middle inner section

[0085] 11 upper inner section

[0086] 12 Arrangement

[0087] 13 Transition piece

[0088] 131 segments

[0089] 132 coupling surface

[0090] 133 middle section

[0091] 134 bore

[0092] 135 lower annular contact surface

[0093] 136 upper annular contact surface

[0094] 137 additional passage opening

[0095] 14 upper flange

[0096] 141 lower flange

[0097] 15 tendon

[0098] 16 Anchor tower foundation lower tower section reinforced concrete tower ring segment steel concrete ring upper tower section

Claims

Patent claims 1. Ring (1), in particular for a wind turbine, comprising: - a lower contact surface (2) which can be placed on the upper end of a reinforced concrete ring or on a steel plate, - an upper contact surface (3) onto which a transition piece (13) or a steel tube tower can be placed, and - an outer contour (5) with a lower outer section (6) which is concave and extends from the lower contact surface (2) towards the upper contact surface (3) while reducing its diameter, and with an upper outer section (7) which adjoins the lower outer section (6) and has a substantially constant diameter.

2. Ring (1) according to one of the preceding claims, wherein the ring (1) is made of cast iron or cast steel.

3. Ring (1) according to claim 2, wherein the ring (1) is manufactured in a casting process as a monolithic component from spheroidal graphite cast iron.

4. Ring (1) according to one of the preceding claims, wherein the upper contact surface (3) is offset radially inwards with respect to the lower contact surface (2).

5. Ring (1) according to one of the preceding claims, wherein the ring (1) has an inner contour (8) with a lower inner section (9) which is convex and extends from the lower contact surface (2) with a reducing diameter in the direction of the upper contact surface (3), a central inner section (10) which adjoins the lower inner section (9) and has a substantially constant diameter, and with an upper inner section (11) which is convex, adjoins the central inner section (10) and extends as far as the upper contact surface (3).

6. Ring according to claim 5, wherein the lower inner section (9) and the middle inner section (10) as well as the middle inner section (10) and the upper inner section (11) each merge continuously into one another.

7. Arrangement (12) comprising a ring (1) according to one of claims 1 to 6 and a tubular transition piece (13), wherein the transition piece (13) is placed on the upper contact surface (3) of the ring (1).

8. The assembly (12) of claim 7, wherein the transition piece (13) has an upper flange (14) on its upper side for attaching a steel tower.

9. Arrangement (12) according to claim 7 or 8, wherein the transition piece (13) is formed integrally with the ring (1), wherein in particular the ring (1) and the transition piece (13) are welded together.

10. Arrangement (12) according to one of claims 7 to 9, wherein the transition piece (13) is composed of several segments (131) arranged side by side in the circumferential direction.

11. Arrangement (12) according to claim 10, wherein the segments (131) have circumferential coupling surfaces (132) extending radially and at least approximately parallel to the axial direction.

12. A tower (17) for a wind turbine, comprising a foundation (18), a lower tower section (19) comprising reinforced concrete ring segments and / or reinforced concrete rings, a ring (1) arranged on the upper side of the lower tower section (19) according to one of claims 1 to 6 or an arrangement according to one of claims 7 to 11.

13. Tower (17) according to claim 12, with a tubular transition piece (13) which is arranged on the ring (1) and preferably welded to the ring (1), wherein the lower tower section (19) is braced by means of tendons (15) which are supported on the one hand on the foundation (18) and on the other hand on the ring (1) or the transition piece (13).

14. Tower (17) according to claim 12 or 13, wherein through openings (4) in the ring (1) are arranged either so that the tendons (15) run within the reinforced concrete ring segments and / or the reinforced concrete rings of the lower tower section (19) or are exposed in the interior of the lower tower section (19).

15. Wind turbine, with a tower (17) according to claim 12 to 14 having a lower tower section (19) and an upper tower section mounted thereon, which carries a turbine and is designed as a tubular steel tower.

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