DE102014204593A1 - Horizontal rotor turbine - Google Patents

Abstract

The invention relates to a horizontal rotor turbine comprising a nacelle; a main shaft disposed in the nacelle, wherein an axis of rotation associated with the main shaft defines an axial direction; an electric generator disposed within the nacelle, at least indirectly driven by the main shaft; and at least one rotor blade. The invention is characterized in that the rotor blade is fastened to an outer rotor sleeve at at least two blade connections spaced apart in the axial direction and the outer rotor sleeve is supported with at least one radial bearing against a lateral surface of the machine nacelle and wherein the outer rotor sleeve and the main shaft are in at least indirect drive connection.

Description

The invention relates to a horizontal rotor turbine for energy production from a fluid flow, in particular a tidal current.

The horizontal rotor turbines preferably used for wind turbines represent a possible design for flow power plants in running waters without a dam structure. Such freely flowing horizontal rotor turbines can be used from a sufficient size for ocean currents, in particular for tidal currents. For the use of a wind force-like design underwater, there is not only the need to consider a much higher fluid density of the driving flow and thus the present Reynolds numbers, but it is also necessary, the plant design to the much difficult installation requirements, especially at a marine site to adapt.

For generic underwater systems usually a modularization is used, for example, from the WO 2007/125349 A2 and DE 10 2008 059 891 A1 is known. For this purpose, first of all a support structure is erected on the body of water, to which a machine nacelle provided with a tower adapter is attached to a coupling device in a subsequent installation step. Instead of a downhole support structure, the nacelle may be coupled to a floatable unit or a land connection support member such as a bridge member.

Typically, the nacelle includes an electric generator and a power train. Furthermore, prior to lowering, a flow energy converter having at least one rotor blade is attached to a rotating unit which is supported on a bearing of the nacelle.

For the rotating unit with typically several propeller-shaped rotor blades outer rotor and guided inside the nacelle, the main rotor carrying the rotor are known. For external rotor configurations is exemplified on the US 2007/0007772 A1 and DE 10 2007 003 618 A1 directed. From these documents, a bearing on a lateral surface of the machine nacelle outer rotor sleeve, which carries at least one rotor blade, forth. In this case, the outer rotor sleeve receives the generator rotor of an electric generator, which is usually equipped with permanent magnets.

Alternatively, by the GB 2 449 436 A proposed, in addition to the outer rotor sleeve, which carries the rotor blades to use another sleeve-shaped element for the generator rotor, which connects axially to the outer rotor sleeve and is rotatably connected thereto. In such an arrangement deformations of the outer rotor sleeve in operation do not affect directly on the components of the electric generator, so that the setting of a constant generator gap can be easily realized. However, such a concept requires a sufficient axial length of the nacelle, so that the tower adapter and the coupling device must be designed on the support structure for high payloads.

By the DE 10 2007 061 185 A1 A design is proposed for a horizontal rotor turbine, in particular for use as a tidal power plant, which provides a main shaft supported within the nacelle for supporting the rotating unit with the rotor blades. By using a main shaft with a large cross-section, it is possible to use this in addition to an air cap as buoyancy element of the rotating unit, so that the radial bearings of the shaft are relieved. This presupposes that essential parts of the main shaft are arranged within the nacelle in a water-guided area. A particularly robust design uses water-lubricated plain bearings, which include a hard-soft pairing, to guide the main shaft. The concept is extended by the use of a separate assembly for the electric generator, which, as by the DE 10 2008 031 615 A1 described with respect to the support structure opposite to the rotating unit with the rotor blades is arranged.

For system control, a pitch adjustment mechanism can be accommodated on the blade connections of the rotor blades. If there is a cyclic flow direction change, as in a tidal current, a pitch adjustment device must allow rotation of the rotor blade by at least 180 °. Such devices have been already for Kaplan turbines by the GB 750951 A called. For tidal power plants is such Vollpitchverstellmöglichkeit from the GB 2347976 B known. Pitch adjustment devices lead to additional system components, with each subcomponent, such as the adjustment mechanism, the associated adjustment drives and the control components used for the pitch adjustment, increase the risk of failure of the system and thus shorten their life. Therefore, a simplified concept with rotor blades fastened rigidly to the blade connections has been proposed for submersible power generation plants which are difficult to access and only with great effort for maintenance. For the realization of a bidirectional approachability, double-symmetric or point-symmetrical Used leaf profiles. In this regard, is exemplified on the US 2007/0231148 A1 . DE 10 2009 057 449 B3 and US 06 104 097 A directed.

To limit the power input for such systems is either slowed down to stall or operated in the high-speed range after reaching the rated power of the impinged rotor, so that the power absorbed by the rotor from the flow is reduced by the drop in the power coefficient. In a direct drive connection between the electric generator and the rotor flow around the system usually a certain generator torque is specified. This can be effected in a system control in the high-speed area, a load reduction to the complete elimination of the supporting generator torque.

If the passage speed number is reached, there is no further possibility in the high-speed range to further reduce the loads occurring during a high-level flow to the horizontal rotor turbine. Accordingly, simplified system concepts without a pitch adjustment device are to be designed for the rarely occurring maximum load case, resulting in heavy system components. As an alternative, the DE 10 2012 106 099 A1 flexurally elastic rotor blades and elastic blade connections. These allow a coupling between sheet bending and blade torsion, which reduces the effective rotor cross-section under strong flow and at the same time moves the rotor blade in the direction of the flag position. However, such elastic rotor blades are only suitable for a unidirectional flow, so that tidal currents can only be used with an additional device for plant tracking. A particularly robust system design without a pitch adjustment device and without components for rotation about the vertical axis therefore requires particularly structurally stable rotor blades. In particular, a blade torsion, which increases the effective flow angle, must be avoided. Exclusive sheet deformation in the direction of impact without substantial torsion is advantageous, but difficult to realize.

The invention has for its object to provide a horizontal rotor turbine, in particular with structurally rigid rotor blades, which has such a uniform load introduction into the drive train that shaft loads are reduced and necessary for the load bearing and storage axial length of the nacelle is shortened. Furthermore, the rotor blades are to be articulated to the rotating unit so that there is a sufficient safety margin at the blade terminals and the subsequent load-bearing components to the tower adapter of the machine nacelle and the coupling device to the support structure for the overload case at high flow. The problem underlying the invention is solved by the features of the independent claim. Advantageous embodiments emerge from the dependent claims.

In order to realize a system concept that is as fail-proof as possible, the inventors have recognized that the load occurring at the blade root of a rotor blade must be axially spread by the use of at least two blade connections spaced apart from one another in the axial direction. In addition, the at least doubly present blade terminals of each rotor blade are secured to an outer race sleeve to further reduce the introduction of point load. The concept of an external rotor sleeve is linked to a main shaft design. While the outer rotor sleeve is supported by means of its own radial bearing against a lateral surface of the nacelle, the main shaft, which drives an electric generator in the nacelle at least indirectly, within the nacelle and preferably has a separate storage. In this way, an electric generator arranged within the machine nacelle can be driven at least indirectly by a main shaft, which in turn is at least indirectly in driving connection with the outer rotor sleeve.

By eliminating significant load components on the main shaft, the associated separate storage can be significantly smaller. Also, the bendline of this arrangement will have significantly smaller deflections, simplifying generator alignment. In addition, a buoyancy compensation can be made smaller, so that the main shaft takes up less space.

For a preferred embodiment, outer rotor sleeve and main shaft are arranged coaxially with each other, so that the machine nacelle is formed axially short. Thus, the length of the machine nacelle in the axial direction is set so that the effects of Turmvorstaus or a wake flow to the support structure are tolerable. An additional extension of the machine nacelle in the axial direction to achieve space for an electric generator or an enlarged bearing distance for the reliable support of lateral forces on the main shaft is not necessary.

By using at least two blade terminals spaced apart in the axial direction, it is possible to rigidly fix a rotor blade to an outer rotor sleeve. In order to achieve a high level of stability at high axial thrust loads, an axial distance of the blade connections of the rotor blade is preferred, which amounts to at least 10% of the sheet longitudinal extent. In the present case, the leaf length is the total length the Auffädellinie the profile sections of a rotor blade from the blade root at the blade terminals and the outer rotor sleeve considered to the outermost blade tip. For sacculated or expansive swept rotor blades will generally deviate the Auffädellinie from the radial beam geometry. In this case, suitable forward swept rotors, which lead away the blade tips in the axial direction of the support structure, especially for axially short machine nacelles preferred.

The further the axial distance of the blade connections of the rotor blade is selected, the better is the load distribution in the axial direction. Therefore, a minimum distance of 20% of the blade connections of the rotor blade in the axial direction in relation to the sheet longitudinal extension is particularly preferred. Further, for a preferred embodiment, the blade is formed in the radially inner region as a split sheet, so that a first blade root portion and a second blade root portion are present, which are each in communication with different blade terminals. For a rotor blade, which is particularly preferably present over at least 10% of the sheet longitudinal extent in the radially inner region as a split sheet, a sufficiently large axial distance of the blade terminals of the rotor blade can be connected to a fluidically effective blade profile. A blade connection typically comprises a plurality of fastening elements, such as a connection flange with a worm ring and other components engaging positively in receptacles in the outer rotor sleeve. From each leaf connection emanating from a Strukturaussteifendes element, which is continued in the respective associated blade root. This can be, for example, a separate rotor blade carrier in the form of a box spar for a rotor blade produced by fiber composite construction.

For a further embodiment of the invention, the outer rotor sleeve comprises at least two separate sleeve elements, so that a realization of a double blade connection with a large axial distance is possible. Each individual sleeve element is preferably provided with a separate radial bearing for support against the lateral surface of the nacelle. In addition, separate, the individual sleeve elements associated thrust bearing can be present.

For a structurally simple design with high reliability, a rotor blade is rigidly attached to the axially spaced blade terminals of the outer rotor sleeve. For a further embodiment of the invention, the blade terminals are hinged with hinges or elastic components. The use of a structurally simplified and robust pitch adjustment is conceivable for a further design. Preferably, then the outer rotor sleeve comprises two circumferentially rotatable relative to each sleeve sleeve elements. In a relative displacement of the sleeve elements in the circumferential direction, a rotation of the blade roots in the respective associated blade connections, which is accompanied by a change in the installation angle of the rotor blade. For adjusting the pitch, therefore, an adjustment actuator between the sleeve elements of the outer rotor sleeve can be used. Such an actuator system can be formed, for example, as a hydraulic system which is supplied by an inductive device contactlessly from the nacelle of the engine with energy.

For a simplified embodiment, there is a rigid coupling between the outer rotor sleeve and the main shaft. In addition, there may be a direct drive connection between the main shaft and the generator rotor of the electric generator. For a preferred further embodiment, the rigid connection between the outer rotor sleeve and the main shaft is replaced by a coupling device with degrees of freedom. Such a coupling device ensures the transmission of the drive torque from the outer rotor sleeve to the main shaft, but allows relative movement to a certain extent, so that position errors between the main shaft and the outer rotor sleeve can be compensated. As a result, deformations or load surges on the outer rotor sleeve are not transmitted directly to the main shaft. Further, between the main shaft and the generator rotor of the electric generator, a transmission for speeding up can be provided. Such a transmission may include additional means to compensate for positional errors.

For a preferred embodiment, the concept according to the invention of a distributed load introduction of the rotor blade forces is linked via a double blade connection to an outer rotor sleeve and a main shaft arranged within the machine nacelle with component-associated bearing and buoyancy components. The component bearings and component self-weight compensating gears reduce static loads and overturning torques and thus load transfer to subsequent components of the powertrain. For this purpose, the outer rotor sleeve on an independent radial bearing. Preferably, a Anströmungshaube is additionally provided on a front side of the nacelle, which comprises a buoyancy element, wherein the Anströmungshaube is rigidly connected to the outer rotor sleeve to carry at least a portion of the rotating unit. In addition, further buoyancy bodies could be attached to the flow hood on an axial extension of the outer rotor sleeve.

The coupling between the outer rotor sleeve and the Anströmungshaube can be done via a radially inner portion of the Anströmungshaube. As far as possible, only driving forces should be transmitted in the circumferential direction. The subsequent main shaft is preferably designed with a lift so dimensioned that the radial bearing of the main shaft is relieved. To achieve this effect, the main shaft is located in a flooded area of the nacelle. Furthermore, there are separate thrust bearings for the outer rotor sleeve and the main shaft, which preferably have track discs.

The at least indirectly driven by the main shaft electrical generator is arranged for a preferred embodiment with respect to the coupling device on the support structure opposite to the outer rotor sleeve. This results in a reduction of the tilting moments on the nacelle and thus a relief of the tower adapter and the coupling device to the support structure. A further improvement of this weight compensation can be achieved by additionally assigning to the electric generator a separate buoyancy element in contact with the ambient water.

The invention will be explained in more detail below on the basis of preferred exemplary embodiments in conjunction with illustration representations. These represent the following:

1 shows a horizontal rotor turbine according to the invention in sectional view.

2 shows a further embodiment of a horizontal rotor turbine according to the invention in sectional view.

In 1 is a simplified schematic representation of the section of a horizontal rotor turbine according to the invention 1 shown. Shown is a modular system design for the machine nacelle 2 the horizontal rotor turbine 1 by means of a conical recording 31 on a tower adapter 30 on a complementary conical coupling pin 32 a coupling device 29 a support structure 27 is attached. To the tower adapter 30 closes the gondola side a support ring 33 which is designed for central weight concentration as a solid casting. Furthermore, one piece is integral with the support ring 33 connected support cylinder 34 in front, which has a lateral surface 11 forms, at which there is a radial bearing 10.1 . 10.2 an outer rotor sleeve 9 holding the rotor blades 7.1 . 7.2 carries, supports. The lateral surface 11 points opposite to the support ring 33 a reduced diameter, so that the radially outer surface of the outer rotor sleeve 9 essentially with the radial extent of the support ring 33 flees. Particularly preferred are the radial bearings 10.1 . 10.2 the outer rotor sleeve 9 designed as a water-lubricated slide bearing in the form of a hard soft pairing.

At the outer rotor sleeve 9 lie for each rotor blade 7.1 . 7.2 two blade connections 8.1 . 8.2 for fixing a rotor blade 7.1 . 7.2 in front. For the present embodiment, each rotor blade 7.1 . 7.2 rigidly to the respectively assigned blade connections 8.1 . 8.2 with the outer rotor sleeve 9 connected. Here is the radially inner region of the rotor blade 7.1 . 7.2 formed as a split sheet, so that a first blade root section 13 with the blade connection 8.1 and a second blade root section 14 with the blade connection 8.2 connected is.

To establish a sheet installation angle are the leaf connections 8.1 . 8.2 typically arranged offset in the circumferential direction by a predetermined angular difference and in addition, the rotor blades 7.1 . 7.2 provided with a sheet twisting. The blade geometry is in the schematically simplified representation of 1 but not shown in detail.

Inside the machine nacelle 2 lies a main wave 3 before, their associated axis of rotation 4 an axial direction 5 the horizontal rotor turbine 1 sets. The main shaft 3 extends through a central opening in the support ring 33 and in the support cylinder 34 and rests there by means of a radial bearing 19.1 . 19.2 against a storage section 20.1 . 20.2 from.

For the present embodiment is the main shaft 3 in direct drive connection to an electric generator 6 , concerning the support structure 27 opposite the outer rotor sleeve 9 is arranged. For the illustrated embodiment, the main shaft carries 3 the generator rotor 17 , which is preferably provided with permanent magnets. In the selected plant design, which is an arrangement of Außenläuferhülse 9 with the rotor blades 7.1 . 7.2 and the electric generator 6 on different sides of the support structure 27 provides a balancing of the plant weight, so that the tipping moment on the tower adapter 30 reduced. In addition, there is the possibility of the section of the nacelle 2 who has the electric generator 6 as a separate generator module 35 form, as a structural unit on the support ring 33 is flanged. During assembly, an additional generator rotor 17 carrying shaft socket 36 with the through the support ring 33 protruding part of the main shaft 3 connected.

By choosing a double blade connection 8.1 . 8.2 for each of the rotor blades 7.1 . 7.2 on a directly subordinate outer rotor sleeve 9 creates a heavy-duty articulation of the rotor blades 7.1 . 7.2 , In this case, the axial distance is preferred A of the leaf connections 8.1 . 8.2 in the axial direction 5 with at least 10% and preferably at least 20% of the leaf extension L chosen to a sufficient stability of the rotor blades 7.1 . 7.2 to achieve.

About a rigid with the outer rotor sleeve 9 Connected airflow hood 23 the rotational drive of the main shaft takes place 3 , For the illustrated preferred embodiment, the coupling of the Anströmungshaube 23 with the main shaft 3 by means of a coupling device 18 realized, the position error between the outer rotor sleeve 9 and the main shaft 3 balances. Therefore, elastic deformation of the outer race sleeve becomes 9 or air cap 23 due to strong, short-term loads, not directly to the main shaft 3 passed. Accordingly, there are separate axial supports, wherein for the illustrated embodiment, two track disc bearings are provided, which are a first thrust bearing 21 , that of the outer rotor sleeve 9 is assigned, and a second thrust bearing 22 for supporting the main shaft 3 serves, form.

The over the coupling device 18 in drive connection and shock-decoupled components of the rotating unit with outer sleeve 9 and flow hood 23 on the one hand and the main shaft 3 On the other hand, integrated buoyancy elements for bearing relief minimize static loads and moments. For this purpose, the main shaft includes 3 a centrally located buoyancy element 24 , Further, an electric generator 6 associated buoyancy element 28 enclosed, to balance the weight of the generator rotor 17 serves. For the development of the buoyancy effect is the area around the main shaft 3 including the generator module 35 a flooded area 26 , wherein the current-carrying components of the electric generator 6 are sealed in a watertight manner.

For the circulating unit is in the flow hood 23 a buoyancy element 25 arranged. As this on one side of the outer rotor sleeve 9 is located to avoid a tilting moment on the axially opposite side of a hollow ring 37 provided, which is rigid with the outer sleeve 9 connected is. In this case, the radially outer surface of the hollow ring closes 37 essentially with the radially outer surfaces of the outer sleeve 9 and the carrying ring 33 in alignment.

2 shows a further embodiment of the embodiment according to 1 , Identical components are provided with matching reference numerals. For the illustrated embodiment, the outer rotor sleeve 9 in two sleeve elements 15.1 . 15.2 each one of the leaf connections 8.1 . 8.2 assigned. Each sleeve element 15.1 . 15.2 is directly through a radial storage 10.1 . 10.2 underlain. In addition, a support structure near thrust bearing 38 the sleeve element 15.1 assigned. Accordingly, there is a support structure remote thrust bearing 39 for the sleeve element 15.2 and the flow hood 23 in front.

In addition, there is between the sleeve elements 15.1 . 15.2 an adjusting device 40 attached, the relative position between the sleeve elements 15.1 . 15.2 in the circumferential direction. This allows the adjustment 40 , the leaf connections 8.1 . 8.2 to adjust relative to each other for setting a predetermined blade mounting angle in the circumferential direction, so that a robust Pitchverstellvorrichtung is present. Furthermore, an axial tracking 41 used to relative to the circumferential direction of the distance of the blade terminals 8.1 . 8.2 to keep constant. This allows the use of structural rotor blades 7.1 . 7.2 , which ensure high torsional stability even under high flow.

For an alternative embodiment not shown in detail is on the axial tracking 41 the leaf connections 8.1 . 8.2 waived. Instead, at least partially elastic rotor blades 7.1 . 7.2 in conjunction with the sleeve elements 15.1 . 15.2 used. Further embodiments of the invention are defined by the following claims.

LIST OF REFERENCE NUMBERS

1

 Horizontal rotor turbine

2

 nacelle

3

 main shaft

4

axis of rotation

5

 axially

6

 electric generator

7.1, 7.2, 7.3

 rotor blade

8.1, 8.2

 blade connection

9

 External rotor sleeve

10.1, 10.2

 radial bearing

11

 lateral surface

12

 Sheet longitudinal extension

13

 first leaf root section

14

 second blade root section

15.1, 15.2

 sleeve member

16

 circumferentially

17

 generator rotor

18

 coupling device

19

 radial bearings

20

 bearing section

21

 first thrust bearing

22

 second thrust bearing

23

 Anströmungshaube

24

 buoyancy element

25

 buoyancy element

26

 flooded area

27

 support structure

28

 buoyancy element

29

 coupling device

30

 tower adapter

31

 conical recording

32

 conical coupling pin

33

 support ring

34

 support cylinder

35

 generator module

36

 shaft stub

37

 hollow ring

38

 thrust

39

 thrust

40

 adjustment

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2007/125349 A2 [0003]
• DE 102008059891 A1 [0003]
• US 2007/0007772 A1 [0005]
• DE 102007003618 A1 [0005]
• GB 2449436 A [0006]
• DE 102007061185 A1 [0007]
• DE 102008031615 A1 [0007]
• GB 750951 A [0008]
• GB 2347976 B [0008]
• US 2007/0231148 A1 [0008]
• DE 102009057449 B3 [0008]
• US 06104097 A [0008]
• DE 102012106099 A1 [0010]

Claims (15)

Horizontal rotor turbine comprising: a machine nacelle ( 2 ); one in the machine nacelle ( 2 ) arranged main shaft ( 3 ), wherein an axis of rotation associated with the main shaft ( 4 ) an axial direction ( 5 ); one inside the nacelle ( 2 ) arranged electrical generator ( 6 ), at least indirectly from the main shaft ( 3 ) is driven; and at least one rotor blade ( 7.1 . 7.2 . 7.3 ), characterized in that the rotor blade ( 7.1 . 7.2 . 7.3 ) at least two in the axial direction ( 5 ) spaced blade terminals ( 8.1 . 8.2 ) on an outer rotor sleeve ( 9 ) is attached and the outer rotor sleeve ( 9 ) with at least one radial bearing ( 10.1 . 10.2 ) against a lateral surface ( 11 ) of the nacelle ( 2 ) and wherein the outer rotor sleeve ( 9 ) and the main shaft ( 3 ) are in at least indirect drive connection. Horizontal rotor turbine according to claim 1, characterized in that the rotor blade ( 7.1 . 7.2 . 7.3 ) rigidly at the leaf connections ( 8.1 . 8.2 ) of the external rotor sleeve ( 9 ) is attached. Horizontal rotor turbine according to one of claims 1 or 2, characterized in that the axial distance of the blade terminals ( 8.1 . 8.2 ) of the rotor blade ( 7.1 . 7.2 . 7.3 ) at least 10%, preferably at least 20% of the leaf longitudinal extent ( 12 ) is. Horizontal rotor turbine according to one of the preceding claims, characterized in that the rotor blade ( 7.1 . 7.2 . 7.3 ) over at least 10% of the leaf longitudinal extent ( 12 ) as a split leaf with a first leaf root section ( 13 ) and a second blade root section ( 14 ), wherein the first blade root section ( 13 ) and the second blade root section ( 14 ) different leaf connections ( 8.1 . 8.2 ) assigned. Horizontal rotor turbine according to one of the preceding claims, characterized in that the outer rotor sleeve ( 9 ) two sleeve elements ( 15.1 . 15.2 ), wherein the rotor blade ( 7.1 . 7.2 . 7.3 ) associated leaf connections ( 8.1 . 8.2 ) on different sleeve elements ( 15.1 . 15.2 ) are arranged. Horizontal rotor turbine according to claim 5, characterized in that the sleeve elements ( 15.1 . 15.2 ) with respect to an axial direction ( 5 ) vertical circumferential direction ( 16 ) are rotatable relative to each other. Horizontal rotor turbine according to one of the preceding claims, characterized in that the outer rotor sleeve ( 9 ) and the main shaft ( 3 ) are arranged coaxially with each other. Horizontal rotor turbine according to one of the preceding claims, characterized in that the outer rotor sleeve ( 9 ) and the main shaft ( 3 ) are rigidly connected. Horizontal rotor turbine according to one of the preceding claims, characterized in that the main shaft ( 3 ) rigidly with a generator rotor ( 17 ) of the electric generator ( 6 ) connected is. Horizontal rotor turbine according to one of the preceding claims, characterized in that between the outer rotor sleeve ( 9 ) and the main shaft ( 3 ) a coupling device ( 18 ) is arranged, which has a drive torque from the outer rotor sleeve ( 9 ) on the main shaft ( 3 ) and position errors between the external rotor sleeve ( 9 ) and the main shaft ( 3 ) compensates. Horizontal rotor turbine according to one of the preceding claims, characterized in that the main shaft ( 3 ) at least one radial bearing ( 19 ) associated with the main shaft ( 3 ) against a storage section ( 20 ) in the nacelle ( 2 ) is supported. Horizontal rotor turbine according to one of the preceding claims, characterized in that the outer rotor sleeve ( 9 ) a first thrust bearing ( 21 ) and the main shaft ( 3 ) a second thrust bearing ( 22 ) assigned. Horizontal rotor turbine according to one of the preceding claims, characterized in that the horizontal rotor turbine ( 1 ) one at a front side of the nacelle ( 2 ) arranged flow hood ( 23 ) with a buoyancy element ( 25 ), wherein the flow hood ( 23 ) rigidly with the outer rotor sleeve ( 9 ) connected is. Horizontal rotor turbine according to one of the preceding claims, characterized in that the main shaft ( 3 ) a buoyancy element ( 24 ) and at least partially in a flooded area ( 26 ) of the nacelle ( 2 ) lies. Horizontal rotor turbine according to one of the preceding claims, characterized in that the horizontal rotor turbine ( 1 ) one the nacelle ( 2 ) supporting support structure ( 27 ), wherein the electric generator ( 6 ) with regard to the support structure ( 27 ) opposite the outer rotor sleeve ( 9 ) is arranged and the Machine nacelle ( 2 ) a the electric generator associated buoyancy element ( 28 ) encloses.

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