METHOD AND APPARATUS FOR ALIGNING WIND TURBINE STRUCTURAL PARTS

Abstract

The present invention relates to an assembly of two structural parts of a wind turbine wherein the structural parts are to be connected in a flange-to-flange connection by a number of bolts and such that a flange of the first structural part and a flange of the second are centrally and rotationally aligned whereby a first borehole in the flange of the first structural part is matched and aligned with a corresponding first borehole in the flange of the second structural part. The structural parts may for example be a tower section or a foundation section. The assembly further comprises a first and a second rotational guide member releasably attached to each of the flanges of the structural parts. Each of the rotational guide members comprises a U-shaped or L-shaped structure of a first leg portion and a second leg portion connected by a central portion, the first leg portion ending in a positioning portion shaped to be inserted into a borehole of the flange, and the second leg portion comprising a stop member, and for at least one of the rotational guide members the structure comprised in the rotational guide member is U-shaped. The stop member of the first rotational guide member is configured for abutment to the second leg portion of the second rotational guide member when the flanges of the first and second structural parts are centrally and rotationally aligned. The invention further relates to a method of positioning and connecting two structural parts of a wind turbine as described above. The method includes first centrally aligning the structural parts with the flanges face-to-face and then rotating the structural part relative to each other until the rotational guide members come into contact with each other.

Claims

1. An assembly of two structural parts of a wind turbine wherein the structural parts are to be connected in a flange-to-flange connection by a number of bolts and such that a flange of the first structural part and a flange of the second are centrally and rotationally aligned whereby a first borehole in the flange of the first structural part is matched and aligned with a corresponding first borehole in the flange of the second structural part, the assembly further comprising a first rotational guide member releasably attached to the flange of the first structural part and a second rotational guide member releasably attached to the flange of the second structural part, and wherein each rotational guide member comprises a U-shaped or L-shaped structure of a first leg portion and a second leg portion connected by a central portion, the first leg portion ending in a positioning portion shaped to be inserted into a borehole, and the second leg portion comprising a stop member, wherein the stop member of the first rotational guide member is configured for abutment to the second leg portion of the second rotational guide member when the flanges of the first and second structural parts are centrally and rotationally aligned, wherein for at least one of the rotational guide members the structure comprised in the rotational guide member is U-shaped.

2. The assembly according to claim 1, wherein for each of the rotational guide members the structure comprised in the rotational guide member is U-shaped.

3. The assembly according to claim 1, wherein the two structural parts comprises a tower section and a foundation section or the two structural parts comprises two tower sections.

4. The assembly according to claim 1 wherein each of the rotational guide members comprises an attachment member configured for the releasably attachment of the rotational guide member to a surface of the flange of one of the structural parts.

5. The assembly according to claim 4, wherein the attachment member comprises a magnet.

6. The assembly according to claim 1, wherein the flange of each structural part comprises a number of boreholes extending from an outer surface to an inner surface, and further comprises a side surface extending between the outer surface and the inner surface, and wherein the U-shaped structure of each of the rotational members comprising the U-shaped structure is dimensioned to be inserted in a borehole of one of the flanges and extend from the borehole along the inner surface and up against the side surface of the flange.

7. The assembly according to claim 6, wherein the second leg portion extend a length larger than a height of the side surface.

8. The assembly according to claim 6, wherein the stop member lies against the side surface of the flange.

9. The assembly according to claim 1, wherein the stop member of each rotational member extends a width transversely to the length of the second leg portion, the width corresponding to the distance between two neighbouring boreholes in the flange.

10. The assembly according to claim 1, wherein each of the rotational members are symmetrical about a plane passing through the first leg portion, the second leg portion and the central portion.

11. The assembly according to claim 1, wherein the first rotational member is inserted in the first borehole in the flange of the first structural part and the second rotational member is inserted in a neighbouring borehole to the first borehole in the flange of the second structural part.

12. The assembly according to claim 1, wherein at least the second leg portion of the U-shaped structure is made of a flexible material such as for example POM.

13. The assembly according to claim 1, wherein the rotational guide members are attached to the flanges prior to assembly and connection of the flanges and such that the second leg portion of the U-shaped structure projects from each of the structural parts.

14. The assembly according to claim 1, wherein the stop member of a rotational guide member is exchangeable.

15. The assembly according to claim 1, wherein the positioning portion of a rotational guide member is exchangeable.

16. The assembly according to claim 1, wherein the assembly further comprises a number of alignment devices attached to the flange of the first or the second structural part and configured for centrally alignment of the structural parts.

17. The assembly according to claim 16, wherein at least one of the alignment devices is a rotational guide member.

18. The assembly according to claim 1, wherein the assembly further comprises at least one sensor arranged at or near at least one of the structural parts.

19. A method of positioning and connecting two structural parts of a wind turbine wherein the structural parts are to be connected in a flange-to-flange connection by a number of bolts and such that a flange of the first structural part and a flange of the second are centrally and rotationally aligned whereby a first borehole in the flange of the first structural part is matched and aligned with/connected to a corresponding first borehole in the flange of the second structural part, the method comprising: positioning a first rotation guide member in the first borehole in the flange of the first structural part; positioning a second rotation guide member in a second borehole in the flange of the second structural part, wherein the second borehole is a neighbouring borehole to the first borehole in the flange of the second structural part; centrally aligning the structural parts with the flanges face-to-face; moving the structural parts towards each other; rotating the first structural part relative to the second while maintaining the flanges face-to-face and until the first rotational guide member comes into contact with the second rotational guide member; and positioning the first structural part on the second structural part.

20. The method according to claim 19 further comprising removing the first and second rotational guide members and connecting the flanges of the first and second structural parts by bolts.

21. The method according to claim 19, wherein the step of centrally aligning the structural parts comprises positioning a number of alignment devices in the second structural part such as to project from the flange and lowering the first structural part over the alignment devices.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In the following different embodiments of the invention will be described with reference to the drawings, wherein:

[0036] FIG. 1 is a sketch of two tower sections of a wind turbine being assembled,

[0037] FIG. 2 is a sketch of a foundation section for a wind turbine comprising a number of alignment devices and a rotational guide member according to an embodiment of the invention,

[0038] FIGS. 3-5 show an embodiment of a rotational guide member in a perspective, a cross sectional, and an exploded view, respectively,

[0039] FIG. 6 shows an embodiment of an alignment device,

[0040] FIGS. 7-8 show a rotational guide member attached to a first and a second structural part, respectively,

[0041] FIGS. 9A-G illustrate the method of positioning two structural parts for connection according to an embodiment of the invention

[0042] FIG. 10 illustrates an embodiment of the method of positioning two structural parts using an L-shaped rotational guide member, and

[0043] FIG. 11 illustrates an embodiment of the method of positioning two structural parts using an alignment devices that also is a rotational guide member.

DETAILED DESCRIPTION OF THE DRAWINGS

[0044] FIG. 1 illustrates two tower sections 2a, 2b of a wind turbine 1 being assembled. Here, a first structural part 2a in the form of a tower section is positioned and in place and a second structural part 2b, such as another tower section or the nacelle (not shown) of a wind turbine, is suspended from a crane 3 and is to be connected with the first structural part 2a in a flange-to-flange connection. For this purpose, a plurality of alignment devices schematically illustrated by numeral 10 may be mounted on the structural parts. For ensuring a correct rotational alignment of the two structural parts 2a, 2b a rotational guide member 4 is attached to each of the flanges of the two structural parts.

[0045] FIG. 2 is a sketch of a structural part forming a foundation section 2c for a wind turbine and prepared for the attachment to another structural part (not shown). The foundation section may equally well form part of an off-shore or of an on-shore wind turbine. The foundation section 2c comprises a flange 5 with a number of boreholes 6 which is to be connected to a corresponding flange of another structural part. The figure shows a rotational guide member 4 attached to the flange 5. The rotational guide member is inserted into one of the boreholes 6 from the underside or the inner side of the flange 5 as illustrated in the later FIGS. 7 and 8. In this way the rotational guide member is positioned such as not to obstruct the outer surface 7 of the flange 5 which is to abut the flange of the other structural part when connected. The rotational guide member is inserted into a specific borehole which corresponds to where the second rotational guide member attached to the second structural part is mounted. In this way, the two rotational guide members can be used to ensure a correct positioning and rotational alignment of the two structural parts. Further, a number of alignment devices 10 are attached to the flange 5. The rotational guide member 4 is preferably positioned with some radial distance (as marked by the arrow 8) to the nearest alignment device. This will ease the positioning of the two structural parts as will be described in more details in relation to FIG. 9. The structural part 2c may further comprise a marking 9 on the exterior of the structural part showing where the rotational guide member 4 and the nearest alignment device 10 are. As these remain visible during positioning of the two structural parts, the marking 9 can aid during a part of the positioning and alignment procedure.

[0046] An embodiment of a rotational guide member is shown in more detail in the FIGS. 3, 4, and 5. FIG. 3 show a rotational guide member 4 in a perspective view. The rotational guide member 4 of FIGS. 3, 4 and 5 comprises a generally U-shaped structure of a first leg portion 301 and a second leg portion 302 connected by a central portion 303. The first leg portion 301 comprises a positioning portion 304 which is shaped to be inserted into a borehole of one of the flanges of the structural parts of the wind turbine. Here the positioning portion is of a generally cylindrical shape with two ring shaped protrusions 305. The diameter of the protrusions 305 corresponds to the diameter of the borehole. Because of the protrusions 305, the positioning portion 304 can be more easily retracted from the borehole when desired. The positioning portion 304 ensures that the rotational guide member 4 is placed correctly on the flange with a view to obtain the desired positioning and centrally and rotationally alignment of the two flanges whereby a first borehole in the first flange is matched and aligned with a corresponding first borehole in the other flange. The positioning portion 304 can be exchanged for example to another portion of another diameter. In this way, the rotational guide member 4 can be easily adapted to fit to other flanges with different borehole sizes.

[0047] In this embodiment of a rotational guide member with a U-shaped structure, part of the second leg portion 302 and central portion 303 is formed by an L-shaped bar 310 which is received in and attached to a holder 309. Hereby the dimension of the central portion 303 can be easily adjusted, so that the same rotational guide member 4 can be used on different types and sized of flanges. For a rotational guide member with an L-shaped structure, the bar 310 would typically be a straight bar. The second leg portion 302 comprises a stop member 306. The second leg portions of a set of two rotational guide members 4a, 4b are configured such as to abut sideways to each other when the flanges they are placed on are centrally and rotationally aligned. This is shown in more detail in FIGS. 9E, F, and G. As an example, the two stop members of two rotational guide members 4a, 4b may be configured for abutting each other, and/or a stop member of two rotational guide members 4a, 4b may be dimensioned to abut the second leg portion of the other rotational guide member (as is the case with the embodiments shown in FIGS. 9E-G). The abutment is the most easily obtained by dimensioning the width 307 of the stop member so that it corresponds to the distance between two neighbouring boreholes in the flanges to be aligned. The stop member 306 is exchangeable and so the rotational guide member can easily be adapted to fit a different type of flange where the distance between the boreholes is different. The positioning portion 304 and the holder 309 for receiving the bar 310 is made of steel or a similar material yielding high stiffness properties. The L-shaped bar 310 and the stop member 306 are preferably made of a flexible material such as a plastic such as for example POM to give the rotational guide member some flexibility to thereby withstand any sideways pushing on the stop member during assembly and alignment of the flanges.

[0048] The rotational guide member 4 further comprises an attachment member 308 configured for the releasably attachment of the rotational guide member to a surface of the flange of one of the structural parts. In this embodiment, the attachment member 308 is a magnet which is attached to or form part of the central portion 303 of the rotational guide member. The attachment member could alternatively or additionally be positioned to form part of the second leg portion 302. The magnet is strong enough to support the weight of the rotational guide member.

[0049] The rotational guide member 4 is shown in a cross-sectional view in FIG. 4 and in an exploded view in FIG. 5. The different parts of the rotational guide member are attached by bolts, screws, rivets or the like fastening members (not shown).

[0050] FIGS. 7 and 8 show a rotational guide member 4 attached to the flange 5 of a first and a second structural part, respectively. The flange 5 of each structural part comprises a number of boreholes 6 extending from an outer surface 7 to an inner surface 702 (see FIG. 8), and further comprises a side surface 701 extending between the outer surface 7 and the inner surface 702. The U-shaped structure of a rotational member 4 is dimensioned to be inserted in a borehole 6 of one of the flanges 5 and extend from the borehole 6 along the inner surface 702 and up against the side surface 701 of the flange. In this way, the outer surface 7 of the flange which is to lie against the other flange is left free and unobstructed by the rotational guide member. When attached to a flange 5, the positioning portion 304 of the rotational guide member is inserted into a borehole 6 (barely visible in FIG. 7) and the second leg portion 302 lies at least partly against the side surface 701 of the flange. In this embodiment, the stop member 306 lies against the side surface 701. Hereby, the rotational guide member maintains its position relative to the flange even if pushed sideways during assembly and positioning of the two structural parts. FIG. 8 further shows a number of bolts 800 loosely inserted in the boreholes 6 ready for connection.

[0051] FIG. 6 shows an embodiment of an alignment device 10. The alignment device is likewise configured for being inserted into a borehole and for releasable attachment to a flange by means of a magnet. When inserted into a borehole, the alignment device extends a considerable length from the flange towards the other structural part for the other structural part to be lowered down over and guided into a central alignment of the two flanges. This is also illustrated in FIGS. 9A and 9B.

[0052] FIGS. 9A-G illustrate the method of positioning two structural parts 2a and 2b for connection according to an embodiment of the invention. The figures show the flanges 5a, 5b of each structural part (not shown to enhance clarity), which are to be centrally and rotationally aligned such that a first borehole 6a of the one flange match and is aligned to a specific first borehole 6a of the other flange.

[0053] A first rotation guide member 4a positioning in the first borehole 6a in the flange 5a of the first structural part 2a. Further, a second rotation guide member 4b is positioning in a second borehole 6b in the flange 5b of the second structural part 2b, wherein the second borehole 6b is a neighbouring borehole to the first borehole 6a in the flange 5b of the second structural part 2b. The rotational guide members 4 are positioned such that the second leg portions project from each of the structural parts. When one of the rotational guide member has an L-shaped structure, only the second leg of the rotational guide member with the U-shaped structure will project from the structural part.

[0054] Also, the method may optionally include the use of a number of alignment devices 10 attached to one or both of the flanges 5. For the sake of simplicity only one alignment device 10 is shown here, however, often a number of alignment devices like for example three to ten, preferably four to eight, such as four or six are used to ease the centrally alignment of the two flanges of the structural parts.

[0055] The two structural parts 2a, 2b are then centrally aligned with the flanges 5a, 5b face-to-face and the structural parts moved towards each other as illustrated by the arrow 901 in FIG. 9A. When the flanges are moved within a certain distance to each other as illustrated in FIG. 9B, the first structural part 1a is then rotated relative to the second 2b while maintaining the flanges face-to-face. This is illustrated by the arrow 902 in FIG. 9C of which an enlarged detail is shown in FIG. 9D. The distance between the structural parts depends on how much the second leg portions of each of the rotational guide members project from the flanges. The structural parts are then rotated relative to each other until the first rotational guide member 4a comes into contact with the second rotational guide member 4b as shown in the enlarged view in FIG. 9E. Here the stop member 306 of the first rotational guide member 4a abuts the second leg portion 302 of the second rotational guide member 4b and vice versa.

[0056] In this situation the flanges 5a, 5b are both centrally and rotationally aligned and the first structural part 2a is then lowered onto and positioned onto the second structural part 2b with the rotational guide members remaining in contact as illustrated by the arrows 903 in FIG. 9F and in a larger view in FIG. 9G where the flanges 5a, 5b abut each other. The rotational guide members can then be removed and the flanges connected by the bolts. It is preferred that the guide members are removed after connecting the flanges by bolts as this ensures visually that the first and second structural parts remains aligned until structural parts are connected. However, removing of one or more of the rotational guide members may be done before connecting the flanges by bolts as the rotational guides typically does not provide any substantial fixating force between the flanges after the flanges have been positioned onto each other.

[0057] FIG. 10 shows an embodiment where a rotational guide member 4d with an L-shaped structure is used in the setup of FIG. 9D. The corresponding rotational guide member 4c with a U-shaped structure has here an extended second leg portion.

[0058] In FIG. 11, an embodiment where one of the alignment devices also being used as a rotational guide member 4e is used in the setup of FIG. 9D. It is observed that the stop member 306 is arranged so that it will interact with the stop member or the second leg portion of the rotational guide member 4a. In FIG. 11, the rotational guide member 4a has a U-shaped structure, however, the rotational guide member 4a of FIG. 11 may also have a L-shaped structure (not shown) without changing the function of the setup.