Patent ID: 12241449

DETAILED DESCRIPTION

In the Figures, like reference numerals designate like or functionally equivalent elements, unless otherwise indicated.

FIG.1shows an offshore wind turbine1according to an embodiment.

The wind turbine1comprises a rotor2connected to a generator (not shown) arranged inside a nacelle3. The nacelle3is arranged at the upper end of a tower4of the wind turbine1. The tower4is arranged on a transition piece5. The transition piece5is a “Super Extended Transition Piece” with a height of 40 meters or more. The transition piece5is erected on a monopile6which is driven into the sea bed7and is partly above the level of the sea water8.

The rotor2comprises, for example, three rotor blades9. The rotor blades9are connected to a hub10of the wind turbine1. A shaft (not shown) connects the hub10to the generator.

The generator is electrically connected to a switch gear11in the transition piece5by means of a high voltage cable (not shown).

The tower4comprises one or more tower sections12,13,14. In the example ofFIG.1, the tower4comprises a bottom tower section12, a middle tower section13, and a top tower section14. The tower sections12,13,14include each one or more flanges15bolted to a corresponding flange15of another tower section12,13,14. Further, the bottom tower section12of the tower4includes a flange16bolted to the transition piece5.

The tower4comprises inside one or more platforms17,18,19,20. The tower4comprises, for example, a low voltage platform17in the bottom tower section12on which a low voltage transformer (not shown) is located. The tower4may further comprise bolt platforms18and19configured for a worker to bolt the corresponding tower sections12,13,14to each other when assembling the tower4.

The transition piece5comprises on its outside a landing platform21to provide access to the interior of the transition piece5and the tower4. The transition piece5comprises further a platform assembly22suspended from a flange23of the transition piece5. The flange23of the transition piece5is bolted to the flange16of the tower4.

The platform assembly22comprises a bottom module24and a top module25. The bottom module24and the top module25are connected to each other by connecting means26.FIG.2shows a perspective enlarged view of the platform assembly22ofFIG.1

The bottom module24comprises at least one first platform27,28. In the example ofFIGS.1and2, the bottom module24comprises a hang-off platform27and a switch gear platform28on which the switch gear11is arranged. Furthermore, the bottom module24may comprise above the switch gear platform28a switch gear footbridge29.

The top module25comprises at least one second platform30. In the example ofFIGS.1and2, the top module25comprises a bolt platform30for a worker to connect the transition piece5and the tower4by means of bolting the flanges16and23to each other. Furthermore, the top module25comprises two or more vertical legs31and a plurality of struts32connecting the two or more vertical legs31.

As can be seen inFIG.2, the top module25comprises e.g., six vertical legs31. Furthermore, the top module25comprises a first horizontal plane33at which the six vertical legs31are connected horizontally by means of the plurality of horizontal struts32. Further, the top module25comprises a second horizontal plane34at which the six vertical legs31are connected horizontally by means of the bolt platform30. The first horizontal plane33is spaced apart from the second horizontal plane34in the vertical direction Z by a first height H1. The first height H1is, for example, larger than two meters, larger than five meters and/or larger than ten meters.

The bottom module24comprises six vertical legs35. Furthermore, the bottom module24comprises a first horizontal plane36at which the six vertical legs35are connected horizontally by means of the hang-off platform27. Further, the bottom module24comprises a second horizontal plane37at which the six vertical legs35are connected horizontally by means of the switch gear platform28. The first horizontal plane36is spaced apart from the second horizontal plane37in the vertical direction Z by a second height H2. The second height H2is, for example, larger than two meters, larger than five meters and/or larger than ten meters.

In the following, a method for manufacturing the wind turbine1ofFIG.1is described with respect toFIGS.3-12.

In step S1of the method, the bottom module24is manufactured.FIG.3illustrates the manufacturing of the individual platforms27,28,30of the bottom module24and of the top module25at separate fixtures (stands)38within a factory hall.FIG.4illustrates the manufacturing of the bottom module24at a fixture (stand)39within the factory hall. The hang-off platform27and the switch gear platform28are each arranged on horizontal portions of the fixture39so as to extend horizontally. Then, the six vertical legs35are connected to the hang-off platform27. Further, the six legs35are connected to the switch gear platform28.

In step S2of the method, the top module25is manufactured at a fixture (stand)40in the factory hall, as shown inFIG.5. The bolt platform30is laid on a horizontal portion of the fixture40. Then, the six legs31are provided and connected horizontally at the second horizontal plane34comprising the bolt platform30. Further, the six legs31are connected horizontally at the first horizontal plane33by means of the plurality of struts32.

Both, the bottom module24and the top module25are self-supporting due to having each the two spaced apart horizontal connections of their legs31,35.

In step S3of the method, the bottom module24and the top module25are assembled to form the platform assembly22, as shown inFIG.6. The bottom module24and the top module25are transported to outside the factory hall. The top module25is lifted by a crane41above the bottom module24. The vertical legs31of the top module25comprise each a backing plate42. The top module25is aligned with the bottom module24by means of the backing plates42. The bottom module24and the top module25are connected with each other by means of the connection means26. The backing plates42can, for example, serve as the connection means26. The alignment and connection of the modules24,25may be supported by a worker standing on a platform of a scaffolding43.

In step S4of the method, the platform assembly22is inserted into the transition piece5of the wind turbine1by means of the crane41. As shown inFIG.7, the platform assembly22is lifted by the crane41and inserted from above into the vertical transition piece5.

In step S5of the method, the platform assembly22is connected to the flange23of the transition piece5to suspend the platform assembly22from the flange23.

In particular, arms44(FIG.2) of the top module25are connected with the flange23, e.g., by means of bolts. Thus, in this example, the platform assembly22is supported by the flange23at six connection points. From these six connection points, the platform assembly22is hanging free into the transition piece5, i.e. has no other connections providing support in the vertical direction Z.

In step S6of the method, pivotable edge elements45of the bolt platform30are pivoted so as to bridge a gap46between the bolt platform30and an adjacent wall portion47, as shown inFIGS.9to11.

FIG.8shows the bolt platform30as part of the platform assembly22. The bolt platform30comprises a main body48and the pivotable edge elements45. Further, there is the gap46between the main body48of the bolt platform30and the adjacent wall portion47because the diameter of the main body48of the bolt platform30is smaller than the diameter of the interior wall of the transition piece5, in particular at the adjacent wall portion47. To avoid items to fall from the bolt platform30through the gap46, the gap46is (partly) closed in the method by means of pivoting the pivotable edge elements45.

FIG.9shows an enlarged cross-section view of a portion of the bolt platform30. The pivotable edge elements45is connected to the main body48of the bolt platform30by means of bolts49.

To bridge the gap46, the pivotable edge elements45are pivoted outwards, as shown inFIG.10and, as enlarged cross-section view, inFIG.11. The pivotable edge elements45are pivoted outwards by pivoting them about the bolts49.

Although the present invention has been described in accordance with preferred embodiments, it is obvious for the person skilled in the art that modifications are possible in all embodiments.

Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements.