DE102013221681B4 - Hybrid tower of a wind turbine - Google Patents

Abstract

Hybrid tower (11) for a wind turbine (2), - wherein a lower section of the hybrid tower (11) is designed as a lattice tower (12) and an upper section of the hybrid tower (11) as a tubular tower (3), - the lattice tower (12) at least comprises three corner posts (13) which are connected to one another via cross members (14) and cross braces (15), and the corner posts (13) are arranged at an angle (α) to a longitudinal axis (7) of the hybrid tower (11), - the Tubular tower (3) consists of at least one tubular segment (16) and - the lattice tower (12) and the tubular tower (3) are detachably connected to one another by means of a transition piece (1), - the transition piece (1) has an adapter shell (17) and adapter plates ( 18), wherein the adapter shell (17) and the adapter plates (18) are detachably connected to one another in such a way that the adapter plates (18) and the adapter shell (17) partially overlap in the longitudinal direction of the hybrid tower (11), with the adapter plates also (18) with the corner posts (13) of the lattice tower (12) ve are connected and the adapter shell (17) is connected to the tubular tower (3), characterized in that- the number of adapter plates (18) corresponds to the number of corner posts (13),- the adapter shell (17) is tubular and at least a lower part of the adapter shell (17) is conical, with the cone angle corresponding to the angle of inclination of the corner posts (13), - the corner posts (13) protrude into the conical area of the adapter shell (17) and - the adapter plates (18) between the adapter shell (17) and the corner posts (13) and have a central post-shaped area for fastening the corner posts (13) which protrudes beyond the adapter shell (17) in the longitudinal direction of the hybrid tower (11).

Description

The present invention relates to a hybrid tower according to the preamble of patent claim 1. Such a hybrid tower is provided with a transition piece for connecting a tubular steel tower to a lattice tower of a wind turbine. Very tall tubular steel towers require a certain level of rigidity because of the vibration and natural frequency that occur. This requires a large tower diameter or a large wall thickness. The anchoring of tubular steel towers is often realized with the help of a flange, particularly often with the help of a T-flange, which is usually clamped to a foundation by means of two rows of anchor bolts arranged in the shape of a ring.

Since the transport of tubular steel towers from the manufacturer's production halls to the installation sites usually has to be realized with the help of heavy-duty transport over land, the maximum transport height is around 4.5 meters due to the height of bridges. The tower segments are usually transported lying down during transport, which is why the maximum diameter of the tower segments in the area of the flange must not exceed the transport height. The distance between the road and the transported tower segments is around 0.1 to 0.2 meters for most heavy-duty transporters. For this reason, the maximum diameter of the tower segments including the flange must not be greater than around 4.3 or 4.4 meters. In order to provide a sufficient base and enough space for positioning the anchor bolts, the outer flange width - i.e. the part of the T-flange that protrudes beyond the diameter of the lateral surface - must be greater than 0.25, usually greater than 0. be 3 meters. This applies in particular to towers over 80 meters high. For this reason, the maximum diameter of the tower in the area of the lateral surface without a flange when using conventional anchoring systems must not be greater than a certain dimension, around 4.0 meters.

Due to the transport-related cross-sectional limitation of the tower segments, other measures must be taken in wind turbines with large towers in order to ensure adequate tower rigidity. One possibility is to design the tower as a lattice-tube hybrid tower. This hybrid tower combines a lattice tower with a tubular tower. This has the advantage that the upper section of the tower, designed as a tubular tower, is very torsion-resistant and the lower section of the tower, designed as a lattice tower, can be transported to the erection site in individual parts, thus enabling a very large standing area, which leads to high flexural rigidity. without exceeding the maximum transport height of the tower segments.

The lattice tower usually consists of at least three corner posts, which are connected by several cross braces and horizontal crossbeams. The corner posts are designed to transfer the bending moments that act perpendicular to the tower axis, as well as to transfer forces that act in the tower axis. The cross braces and crossbeams of the lattice tower are designed to transfer torsional moments acting around the tower axis as well as forces acting perpendicular to the tower axis. In the case of the tubular tower, all forces and moments are transferred via the cylindrical shell of the tube. This gives rise to the problem of connecting the round tubular tower to the square lattice tower. Such a compound is from a generic hybrid tower after DE 103 39 438 A1 known. The connection is designed here as a transition piece with an adapter shell and adapter plates. Also the DE 10 2005 017 162 A1 shows a transition piece with an adapter shell and adapter plates, namely tab segments. The transition piece is designed here in the form of a pot and is provided between a lattice tower and a nacelle of a wind turbine.

It is an object of the invention to realize a transition between tubular tower and lattice tower without impairing the stability of the tower.

The object is achieved according to the invention by a hybrid tower of a wind turbine with the features of main claim 1 .

The hybrid tower according to the invention comprises a transition piece with an adapter shell and a number of adapter plates. The adapter shell is tubular and has at least one flange with the same diameter as the lowermost section of the tubular tower, so that the adapter shell can be connected to the tubular tower. Several elongated adapter plates are detachably arranged on the adapter shell. The adapter plates are detachably arranged on the adapter shell in such a way that the adapter plate and adapter shell overlap in the longitudinal direction of the tower and part of the adapter plate protrudes from the adapter shell in the longitudinal direction of the tower. The adapter plate is designed in such a way that it can be connected to a corner post of the lattice tower. The number of installed adapter plates therefore also corresponds to the number of corner posts of the lattice tower used. The combination of tubular adapter shell and adapter plates creates a transition from a round tubular tower to a square lattice tower.

The adapter plates are double Y-shaped, so that the vertical part of the Y forms a first central post-shaped area for attaching the adapter plate to the corner post of the lattice tower and the fanned-out part of the Y forms a second area for attaching the adapter plate to the adapter shell. Due to the double Y-shaped design of the adapter plate, essentially four webs are formed which protrude from the central area of the adapter plate and are designed to receive fastening means for fastening to the adapter shell. The fastening means arranged on the webs are also responsible for transferring loads from the adapter shell to the adapter plate. To accommodate the fasteners, the adapter plate is prepared with bores that are mainly located on the webs. In this way, essentially two upper and two lower fields with fasteners are formed on each adapter plate.

Intensive investigations have shown that the webs and the bores arranged thereon for receiving fastening means are advantageously aligned at an angle of 20-45° to the longitudinal axis of the adapter plate. It has been shown that in this way the vertical loads can be introduced as evenly as possible, without large jumps in rigidity, from the adapter shell via the adapter plate into the corner post of the lattice tower, and thus stress concentrations in the adapter shell and the corner post can be avoided.

In order to avoid overloading individual fastening means, the lower fields with fastening means are advantageously designed in such a way that the fastening means are perpendicular to the expected bending direction of the adapter plate. The upper panels with fastening means are advantageously arranged in such a way that the bending directions of the adapter shell are perpendicular to the outermost fastening means of the panel. This arrangement of the fields is intended to ensure that no fasteners are exposed, so that an individual fastener can be overloaded and stress peaks in the area of the fasteners in the adapter plate and the adapter shell are avoided.

The fastening means can be, for example, screws, rivets or locking ring bolts, but screws are advantageously used since they can be detached again when servicing the transition piece and/or the tower. All screw connections should be designed as high-strength, pre-tensioned screw connections (GV connections).

The central, post-shaped area of the adapter plate is adapted to the shape of the corner post so that the adapter plate can be inserted into the corner post and fastened. This can be done, for example, by bending the adapter plate along the longitudinal axis or by dividing the adapter plate along the longitudinal axis. Dividing the adapter plate reduces the amount of work involved in manufacturing the adapter plate, since the step of bending along the longitudinal axis is eliminated. Advantageously, the stem-shaped area of the adapter plate should be guided to the connection of the next cross brace of the lattice tower and not end between two cross braces, thus ensuring a safe transfer of forces and moments from the tubular tower section to the lattice tower section.

In the case of the lattice tower, the corner posts define the flexural rigidity and the cross braces the torsional rigidity, while in the tubular tower both are defined by the tower shell. The design of the adapter plate described here ensures for the first time that the vertical forces and bending moments of the tubular tower that occur are transferred cleanly to the corner posts of the lattice tower, while the torsional moments and shear forces from the adapter shell are transferred directly to the crossbeam of the lattice tower below the adapter.

Advantageously, the adapter shell is conical, with a cone angle of the adapter shell corresponding to the angle of inclination of the corner posts. This ensures that the adapter plate can be made compact and the vertical forces and bending moments are mainly transmitted via shear. The offset moments resulting from the offset between the adapter shell and the corner post remain low. The production (bending) of the adapter plate is also easier for a conical adapter. The adapter shell can be made from a formed sheet metal, which means that the adapter shell can be manufactured very cheaply compared to cast components. The transition piece is advantageously made of steel.

According to the invention, in a further embodiment, only a lower part of the adapter shell is conical; here, too, the cone angle should be adapted to the angle of inclination of the corner posts. The upper part of the adapter shell is designed cylindrically, as this makes it easier to mount the tubular tower on the adapter shell. The adapter shell is designed in such a way that segments of an existing tubular tower can be mounted on the transition piece.

The conical adapter can also be divisible. Thus, the diameter of the Adapter shell can also be larger than the diameter limited by the transport restrictions and the diameter possible for transport can be fully utilized for the tubular tower. The parts of the adapter shell are advantageously connected to one another with a strap connection.

Since the adapter plate transfers the vertical forces and bending moments via shear from the adapter shell to the corner standard, the eccentricity between the adapter shell and corner standard also generates a misalignment moment, which must be absorbed by the corner standards and the adapter shell. The adapter shell can only absorb forces perpendicular to the plane of the shell to a limited extent, so the adapter shell is advantageously reinforced with stiffening ribs above and/or below the adapter plate. An arrangement of a stiffening rib at the upper end of the connection of the adapter plate and a stiffening rib below the connection of the adapter plate is particularly advantageous. If a conical adapter is used, it is advisable to place an additional stiffening rib in the transition between the cylindrical and conical shell. This additional stiffening rib prevents the adapter shell from buckling under pressure at this point and the kink occurring in the transition area between the conical and cylindrical area from being straightened out under tensile stress. The bottom stiffening rib is also used to transfer the torsional moments and shear forces (forces acting perpendicularly to the tower axis) to the underlying cross member and from there to the framework of the lattice tower. When connecting the lower stiffening rib to the cross member, it should be avoided as far as possible that the adapter shell stands up on the cross member or introduces significant vertical loads. This can be done, for example, with a spacer between the adapter shell and the cross member. The gap should be defined in such a way that it does not close even under extreme loads. The bottom stiffening rib now acts like a spring that can transfer horizontal loads, but only to a limited extent vertical loads. The stiffening ribs should be designed as a T-profile or L-profile in order to prevent buckling of the stiffening rib as such.

With the described combination of corner post, adapter plates, adapter shell, stiffeners and crossbeams, it is possible to transfer the occurring forces and moments of the tube section cleanly to the relevant components of the lattice tower.

The transition piece is advantageously arranged at the level of a blade tip of the erected wind turbine. Thus, the very slim and torsionally rigid tubular tower reaches to the blade tip, creating a lot of space for the blades. This allows the sheets to be designed very softly and therefore economically.

The transition piece can be connected to the tubular tower conventionally, e.g. with ring flange connections or strap connections. If the adapter needs to be divided, this should also be done with strap connections. Advantageously, the connections are screwed, because damaged components can be replaced quickly and inexpensively and unfavorable notch cases can be avoided.

The transition piece in the hybrid tower according to the invention is designed in such a way that no connections are welded.

Furthermore, the invention also relates to a wind turbine with the hybrid tower described above.

Further details of the invention emerge from the drawings based on the description.

• 1 eine Windturbine mit einem aus dem Stand der Technik bekannten Rohrturm,
• 2 einen erfindungsgemäßen Hybridturm,
• 3 eine Außenansicht des Übergangsstücks,
• 4 eine Innenansicht des Übergangsstücks,
• 5 eine erste Draufsicht einer Adapterplatte,
• 6 eine zweite Draufsicht der Adapterplatte.
• 7 Detail Ansicht eines Distanzstücks zwischen Übergangsstück und Querträger

Show in the drawings

• 1 a wind turbine with a tubular tower known from the prior art,
• 2 a hybrid tower according to the invention,
• 3 an exterior view of the transition piece,
• 4 an interior view of the transition piece,
• 5 a first plan view of an adapter plate,
• 6 a second plan view of the adapter plate.
• 7 Detail view of a spacer between transition piece and crossbeam

In 1 a wind turbine 2 is shown with a tubular tower 3 known from the prior art, a machine house 4 mounted on the tower 3 and a rotor 5 with a hub 8 and three rotor blades 6 mounted rotatably about a blade axis. The hub 8 is fastened to a rotor shaft rotatably mounted in the nacelle 4 . According to this embodiment, the tubular tower 3 is made up of a plurality of tubular segments 16 .

The details of an axial direction 9, radial direction 10 and details of top and bottom used below apply to the longitudinal axis 7 of the erected tower 3 of the wind turbine 1.

2 shows the hybrid tower 11 according to the invention, with an upper section of the hybrid tower 11 is designed as a tubular tower 3 and a lower section as a lattice tower 12 . The tubular tower 3 and the lattice tower 12 are connected to one another via the transition piece 1 . The lattice tower 12 comprises at least three, in this exemplary embodiment four, corner posts 13 which are connected to one another via a number of crossbeams 14 and crossbars 15 . The corner posts 13 are designed to transfer the bending moments that act perpendicularly to the tower axis 7 and to transfer forces that act in the tower axis 7 . The transverse struts 15 of the lattice tower 12 are designed for the transfer of torsional moments that act around the tower axis and for forces that act perpendicular to the tower axis 7 . The corner posts 13 are arranged at an angle of inclination to the axis 7 of the tower. The tubular tower 3 is connected to the lattice tower 12 via the transition piece 1 . Existing pipe segments 16 from the known tubular tower 3 can be used for the tubular tower 3; here, for example, the top two segments 16 of the known tubular tower 3 are used. The transition piece 1 is placed at the level of the tip of the rotor blade 6 which is in the lowest position. The hybrid tower 11 is thus designed to be very slim in the area of the rotor 5, so that it is ensured that the rotor blades 6 are released from the hybrid tower 11 even when there is a great deal of bending. Below the rotor 5, the width of the lattice tower 12 can increase freely, so that a large footprint and thus a stable stand of the hybrid tower 11 is ensured.

In 3 the transition piece 1 is shown in an installed state on the lattice tower 12 . The transition piece 1 consists of an adapter shell 17 and several adapter plates 18. The number of adapter plates 18 corresponds to the number of corner posts 13 of the lattice tower 12, in this case four pieces. The adapter shell 17 is partially conical in this embodiment, the cone angle α _shell of the adapter shell 17 corresponds to the angle of inclination α _stiel of the corner struts 13. Due to the conical shape of the adapter shell 17, the adapter plate 18 can be made compact and vertical forces and bending moments are mainly caused by shear transferred from the adapter shell 17 to the corner posts 13 of the lattice tower 12. The offset moments caused by the offset δ between the adapter shell 17 and the corner post 13 remain small. The production of the adapter plate is also easier for a conical adapter shell 17 since the adapter plate 18 does not have to compensate for the difference in inclination between the adapter shell 17 and the corner post 13 . An upper section of the adapter shell 17 in the area of the connection to the tubular tower 3 is of cylindrical design, thus ensuring easier assembly and better dissipation of forces and moments from the tubular tower 3 . In order to be able to use the maximum transport diameter for the tubular tower 3, the adapter shell 17 is designed to be divided here. The diameter of the lower area of the adapter shell 17 can thus exceed the maximum transport diameter when installed. During transport, the parts of the adapter shell 17 are taken apart so that the width to be transported is reduced. The parts of the adapter shell 17 are connected to one another here via a screwed strap connection 20 . The adapter plates 17 are detachably connected to the adapter shell 17 by means of fastening means 19; here the fastening means 19 are designed as screw connections.

4 shows an interior view of the adapter shell 17, with an annular flange 21 for fastening the tubular tower 3 to the adapter shell 17 of the transition piece 1. In order to prevent the adapter shell 17 from being deformed by forces acting perpendicularly to the plane of the shell, the adapter shell 17 is provided with at least one stiffening rib 22 stiffened. In this embodiment, the adapter shell 17 is designed with a total of three stiffening ribs 22 . A first stiffening rib 22a is disposed above the adapter plate 18 and a second stiffening rib 22b is disposed below the adapter plate 18. The lower stiffening rib 22b is also used to transmit the torsional moments and shear forces (forces acting perpendicularly to the tower axis) to the underlying horizontal crossbeam 14 of the lattice tower 12 and from there to the framework of the lattice tower defined by the crossbars 15 and the crossbeams 14 Lattice tower 12 to pass. When connecting the lower stiffening rib 22b to the crossbeam 14, it should be avoided as far as possible that the adapter shell 17 stands up on the crossbeam 14 or introduces appreciable vertical loads. The gap should be defined in such a way that it does not close even under extreme loads. The bottom stiffening rib 22b now acts like a spring that can transfer horizontal loads, but only to a limited extent vertical loads. If the adapter shell 17 has a conical design, a stiffening rib 22c is also arranged in the area of the transition from the conical to the cylindrical area. This stiffening rib 22c prevents the adapter shell 17 from buckling at this point under compressive load and from straightening the kink occurring in the transition area between the conical and cylindrical area under tensile load. The stiffening ribs 22 are advantageously designed as a T-profile or L-profile, thus buckling of the stiffening rib 22 as such is prevented.

5 shows the adapter plate 18 from a plan view orthogonal to a longitudinal axis 23 of FIG Adapter plate 18. The adapter plates 18 are double Y-shaped and have a first central area for fastening the adapter plate 18 to the corner post 13 of the lattice tower 12. The central area is provided with bores 26 for accommodating fasteners 19 . In an upper area, the double Y-shape forms four webs 27 which protrude from the central area of the adapter plate 18. The webs 27 are designed to receive the fastening means 19 for fastening the adapter plate 18 to the adapter shell 17 . The fastening means 19 arranged on the webs 27 are also responsible for transferring loads from the adapter shell 17 to the adapter plate 18 . To accommodate the fastening means 19, the adapter plate 18 is provided with bores 26, which are mainly arranged on the webs 27. Essentially, two upper 29 and two lower 28 fields with fastening means 19 for fastening the adapter shell 17 are formed on each adapter plate 18. The adapter shell 17 is of course provided with corresponding bores 26 for receiving the fastening means. In order to avoid stress concentrations in the adapter plate 18, the transitions from the webs 27 to the central area of the adapter plate 18 are formed with a radius R ₁ , R ₂ , R ₃ . The radius R ₁ , R ₂ , R ₃ should be at least 150 mm, but the radius R ₁ , R ₂ , R ₃ is advantageously at least 500 millimeters. The radii R ₁ , R ₂ , R ₃ can be of the same size, but they are advantageously of different sizes and adapted to the loads in the respective area of the adapter plate 18 .

Advantageously, the webs 27 and the bores 26 arranged thereon for receiving the fastening means 19 are aligned at an angle β of 20-45° to the longitudinal axis of the adapter plate 18 . It has been shown that in this way the vertical loads can be introduced as uniformly as possible from the adapter shell 17 via the adapter plate 18 into the corner post 13 of the lattice tower 12 without any major jumps in stiffness, and stress concentrations in the adapter shell 17 and the corner post 13 can thus be avoided.

In order to avoid overloading individual fastening means 19, the two lower fields 28 with fastening means 19 are advantageously designed in such a way that the fastening means 19 are perpendicular to the expected bending direction of the adapter plate 18. The upper fields 29 with fastening means 19 are advantageously arranged in such a way that the bending directions of the adapter shell 17 are perpendicular to the outermost fastening means of the field 29. This arrangement of the fields 28 and 29 is intended to ensure that no fastening means 19 is exposed, which means that an individual fastening means 19 can be overloaded and stress peaks in the area of the fastening means 19 in the adapter plates 18 and the adapter shell 17 are avoided.

6 shows the adapter plate 18 in the direction of the longitudinal axis 23. The adapter plate 18 is bent around the longitudinal axis 23, so that the central area of the adapter plate 18 assumes a V-shape with two legs. The spread of the two legs is defined by the corner post 13 of the lattice tower 12 used, so that the contact surfaces 30 of the central area of the adapter plate 18 run parallel to a corresponding contact surface of the corner post 13 of the lattice tower 12 . The webs 27 also have an angle to the contact surfaces 30 so that the webs 27 run parallel to the outer surface of the adapter shell 17 and the bores 26 in the adapter plate 18 are aligned with the bores 26 in the adapter shell 17 . In a further embodiment, the adapter plate 18 can be of divided design instead of being bent about the longitudinal axis 23 . Here, the adapter plate 18 is cut along the longitudinal axis 23, so the two parts of the adapter plate 18 can be arranged with the desired spread to each other.

7 shows the connection of the stiffening rib 22b to the crossbeam 14 via a spacer 32. The spacer should be defined in such a way that the gap between the stiffening rib 22b and the crossbeam 14 does not close even under extreme loads. The gap between the stiffening rib and the cross member should be at least 20 mm. The bottom stiffening rib 22b now acts like a spring that can transfer horizontal loads, but only to a limited extent vertical loads.

Reference List

1

transition piece

2

wind turbine

3

tubular tower

4

machine house

5

rotor

6

rotor blade

7

longitudinal axis of the tower

8th

hub

9

axial direction

10

radial direction

11

hybrid tower

12

lattice tower

13

corner post

14

cross member

15

cross brace

16

pipe segments

17

adapter shell

18

adapter plate

19

fasteners

20

tab connection

21

ring flange

22

stiffening rib

23

Longitudinal axis of the adapter plate

24

Upper area of the adapter plate

25

Lower area of the adapter plate

26

drilling

27

web

28

lower field

29

upper field

30

contact surface of the adapter plate

31

Central area of the adapter plate

32

spacer

33

bending line

δ

offset

α handle

Angle of inclination of the corner posts

αshell

Angle of inclination of the adapter shell

β

angle

R1

radius

R2

radius

R3

radius

Claims (12)

Hybrid tower (11) for a wind turbine (2), - a lower section of the hybrid tower (11) being designed as a lattice tower (12) and an upper section of the hybrid tower (11) being designed as a tubular tower (3), - the lattice tower (12) at least comprises three corner posts (13) which are connected to one another via cross members (14) and cross braces (15), and the corner posts (13) are arranged at an angle (α) to a longitudinal axis (7) of the hybrid tower (11), - the Tubular tower (3) consists of at least one tube segment (16) and - the lattice tower (12) and the tubular tower (3) are detachably connected to one another by means of a transition piece (1), - the transition piece (1) has an adapter shell (17) and adapter plates ( 18), wherein the adapter shell (17) and the adapter plates (18) are detachably connected to one another in such a way that the adapter plates (18) and the adapter shell (17) partially overlap in the longitudinal direction of the hybrid tower (11), with the adapter plates also (18) with the corner posts (13) of the lattice tower (1 2) are connected and the adapter shell (17) is connected to the tubular tower (3), characterized in that - the number of adapter plates (18) corresponds to the number of corner posts (13), - the adapter shell (17) is tubular and at least one lower part of the adapter shell (17) is conical, with the cone angle corresponding to the angle of inclination of the corner posts (13), - the corner posts (13) protrude into the conical area of the adapter shell (17) and - the adapter plates (18) between the adapter shell (17) and the corner posts (13) and have a central post-shaped area for fastening the corner posts (13), which protrudes beyond the adapter shell (17) in the longitudinal direction of the hybrid tower (11). Hybrid tower (11) after claim 1 , characterized in that the adapter plate (18) has a second area for fastening the adapter shell (17), the second area of the adapter plate (18) being viewed orthogonally to a longitudinal axis (23) of the adapter plate (18) as viewed from the front webs (27) projecting out from the upper part of the central area of the adapter plate, so that the adapter plate (18) essentially forms a double Y-shape, and the webs (27) for receiving fastening means (19) for fastening the adapter shell (17) and adapted to transfer loads from the adapter shell (17) into the corner post (13). Hybrid tower (11) after claim 2 , characterized in that the webs (27) of the adapter plate (18) are aligned substantially at an angle (β) of 20-45 ° to the longitudinal axis (23) of the adapter plate (18). Hybrid tower (11) according to one of the preceding claims, characterized in that the central post-shaped area of the adapter plate (18) is designed in such a way that it can be inserted into the corner post (13) of a lattice tower (12) and connected to the corner post (13) via fastening means (19) is connectable. Hybrid tower (11) after claim 4 , characterized in that the central rod-shaped area of the adapter plate (18) has a length such that the adapter plate (18) extends to a connection of a first cross brace (15) of the lattice tower (12). Hybrid tower (11) according to one of the preceding claims, characterized in that the adapter shell (17) has bores (26) for receiving fastening means (19) for fastening the adapter plate (18) to the adapter shell (17). Hybrid tower (11) according to one of the preceding claims, characterized in that the adapter shell (17) has at least one stiffening rib (22) pointing radially inwards. Hybrid tower (11) after the claims 6 and 7 , characterized in that the adapter shell (17) has at least two stiffening ribs (22) pointing inward, a first stiffening rib (22a) being arranged above and a second stiffening rib (22b) being arranged below the bores (26). Hybrid tower (11) after claim 8 , characterized in that the second stiffening rib (22b) is detachably connected to one of the cross members (14) via at least one spacer (32). Hybrid tower (11) according to one of the preceding claims, characterized in that the adapter shell (17) is designed to be divisible along the longitudinal axis (7) in such a way that the respective parts of the adapter shell (17) have a width of about 4 not exceed .3 meters. Hybrid tower (11) after claim 10 , characterized in that the parts of the adapter shell (17) are detachably connected to one another by means of a screw connection. Wind turbine (2) with a hybrid tower (11) according to one of the preceding claims and a machine house (4) rotatably mounted thereon, a rotor shaft arranged rotatably in the machine house (4) and a rotor (5) arranged on the rotor shaft with rotor blades ( 6).

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