A METHOD FOR ERECTING A WIND TURBINE TOWER USING STUD BOLTS

Abstract

A method for erecting a wind turbine tower is disclosed. A tower section (8) comprising a lower flange (9) and an upper flange (10), and a plurality of stud bolts (6) and nuts (7) are provided. The tower section (8) is oriented in an upright position with the lower flange (9) below the upper flange (10), and stud bolts (6) are positioned in bolt holes (12) in the lower flange (9) with nuts (7) arranged on an upper side of the lower flange (9). The tower section (8) is lifted to a mounting position on top of another tower section (13), and a flange combination is formed by aligning the bolt holes (12) formed in the lower flange (9) of the tower section (8) with bolt holes (15) formed in an upper flange (14) of the other tower section (13), while advancing the stud bolts (6) through the bolt holes (12, 15). The invention further provides a socket tool (16) for screwing nuts (7) onto stud bolts (6) in a manner which positions the stud bolts (6) correctly with respect to a flange (9).

Claims

1. A method for erecting a wind turbine tower, the method comprising the steps of: providing a tower section comprising a lower flange and an upper flange, each flange being provided with a plurality of through-going bolt holes, providing a plurality of stud bolts and a pair of nuts for each stud bolt, mounting a nut to one end of each stud bolt, orienting the tower section in an upright position with the lower flange below the upper flange, positioning stud bolts in the plurality of bolt holes in the lower flange with the nuts arranged on an upper side of the lower flange, lifting the tower section to a mounting position on top of another tower section, forming a flange combination by aligning the through-going bolt holes formed in the lower flange of the tower section with through-going bolt holes formed in an upper flange of the other tower section, while advancing the stud bolts through the bolt holes, mounting a nut on a lower part of each of the stud bolts, and tensioning the stud bolts, thereby securing the tower section to the other tower section.

2. The method according to claim 1, wherein the step of mounting a nut on a lower part of each of the stud bolts comprises the steps of: mounting a socket tool on an end part of one of the stud bolts, adjusting a position of the stud bolt relative to the flange combination, using the socket tool, such that a predetermined portion of the stud bolt is positioned above the lower flange, and mounting a nut on the lower part of the stud bolt and moving the nut into abutment with the upper flange of the other tower section.

3. The method according to claim 2, wherein the socket tool comprises a bolt engaging part comprising a body having an inner cavity arranged to receive an end part of a stud bolt, a stud bolt engaging arrangement configured for positively engaging the stud bolt and transferring movements of a tool to the stud bolt, and a length adjuster configured for adjusting a free length of the end part of the stud bolt, and wherein the step of adjusting a position of the stud bolt is performed by operating the length adjuster.

4. The method according to claim 3, wherein the inner cavity of the body of the socket tool is provided with an inner thread corresponding to a threaded portion of the stud bolt and with an end portion at an open end of the inner cavity, wherein the length adjuster of the socket tool comprises an inner part arranged in a portion of the inner cavity and being provided with an outer thread being arranged in threaded engagement with the inner thread of the inner cavity, the inner part being provided with an end portion, and wherein the step of adjusting a position of the stud bolt comprises operating the length adjuster until the end portion of the body abuts a nut arranged on the upper part of the stud bolt and the end portion of the inner part abuts an upper end of the stud bolt.

5. The method according to claim 4, wherein the stud bolt engaging arrangement of the socket tool comprises a tool engaging part, and wherein the step of operating the length adjuster comprises operating a driving tool engaging the tool engaging part.

6. The method according to claim 2, further comprising the step of removing the socket tool from the upper part of the stud bolt.

7. The method according to claim 1, wherein the step of positioning stud bolts in the plurality of bolt holes in the lower flange is performed using a bolt gripping tool.

8. The method according to claim 7, wherein the bolt gripping tool comprises a gripping portion arranged to grip a stud bolt and a moving portion arranged to move the gripping portion, and wherein the step of positioning the stud bolts in the plurality of bolt holes comprises the steps of: moving the gripping portion to a position of a stud bolt by means of the moving portion, gripping the stud bolt by means of the gripping portion, moving the gripping portion and the stud bolt to a bolt hole by means of the moving portion, positioning the stud bolt in the bolt hole, and releasing the stud bolt from the gripping portion.

9. The method according to claim 8, wherein the step of gripping the stud bolt by means of the gripping portion is performed by means of a magnet forming part of the gripping portion.

10. The method according to claim 8, wherein the steps of moving the gripping portion comprise lifting and/or swinging the gripping portion.

11. The method according to claim 1, wherein the step of orienting the tower section in an upright position comprises positioning the tower section on at least two tower supports, thereby arranging the lower flange at a level about the ground.

12. The method according to claim 1, wherein the step of tensioning the stud bolts is performed using a hydraulic tensioning tool.

13. A socket tool for screwing threaded nuts onto stud bolts, the socket tool comprising: a body formed with an inner cavity arranged to receive therein an end part of a stud bolt, a stud bolt engaging arrangement configured for positively engaging the stud bolt and transferring torque from a drive tool to the stud bolt, and a length adjuster configured for adjusting a free length of the end part of the stud bolt.

14. The socket tool according to claim 13, wherein the inner cavity of the body is provided with an inner thread corresponding to a threaded portion of the stud bolt.

15. The socket tool according to claim 14, wherein the length adjuster comprises: an inner part arranged in a portion of the inner cavity and being provided with an outer thread being arranged in threaded engagement with the inner thread of the inner cavity, the inner part being provided with an end portion.

16. The socket tool according to claim 15, wherein the body is provided with an end portion at an open end of the inner cavity, and wherein the end portion of the inner part is arranged inside the inner cavity at a distance from the end portion of the body.

17. The socket tool according to claim 16, wherein the inner thread of the body extends over only a part of an inner surface of the inner cavity, and wherein the part of the inner surface of the inner cavity without the inner thread is arranged in a region adjacent to the end portion of the body.

18. The socket tool according to claim 13, wherein the stud bolt engaging arrangement comprises a tool engaging part.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0085] The invention will now be described in further detail with reference to the accompanying drawings in which

[0086] FIGS. 1-14 illustrate a method for erecting a wind turbine tower in accordance with an embodiment of the invention,

[0087] FIGS. 15 and 16 illustrate adjusting of a position of a stud bolt relative to a flange connection, using a socket tool according to an embodiment of the invention, and

[0088] FIGS. 17 and 18 are perspective views of a body and an inner part, respectively, of a socket tool according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0089] FIGS. 1-14 illustrate a method for erecting a wind turbine tower in accordance with an embodiment of the invention.

[0090] In FIG. 1 a bolt gripping tool 1 and three tower supports 2 have been positioned at a site where the wind turbine tower is being erected.

[0091] FIG. 2 shows the bolt gripping tool 1 in more detail. It can be seen that the bolt gripping tool 1 comprises three gripping portions 3, in the form of magnets, and three moving portions 4, in the form of electrical cable winches. Each gripping portion 3 is connected to a separate moving portion 4, thereby allowing each gripping portion 3 to be moved independently of any of the other gripping portions 3.

[0092] In FIG. 3 a container 5 with a plurality of stud bolts 6 has been positioned next to the bolt gripping tool 1. A nut 7 is mounted to an end of each of the stud bolts 6.

[0093] In FIG. 4 a tower section 8 is in the process of being oriented in an upright position. The tower section 8 comprises a lower flange 9 and an upper flange 10, arranged at opposing ends of the tower section 8. Prior to the movement of the tower section 8 which is illustrated in FIG. 4, the tower section 8 will normally be lying on the ground with its longitudinal axis arranged parallel to the ground, i.e. along a substantially horizontal direction. The movement towards the upright position is then performed by elevating the part of the tower section 8 which contains the upper flange 10, as illustrated by arrow 11. When this movement has been completed, the tower section 8 will be in the upright position, i.e. the longitudinal direction of the tower section 8 will be arranged in a substantially vertical direction, with the lower flange 9 arranged below the upper flange 10.

[0094] In FIG. 5 the tower section 8 has been oriented in the upright position, and is in the process of being lowered onto the three tower supports 2. When this movement has been completed, the lower flange 9 of the tower section 8 will rest on the three tower supports 2.

[0095] The tower section 8 is further being positioned in such a manner that the bolt gripping tool 1 and the container 5 with stud bolts 6 are arranged inside the tower section 8, i.e. within the wall of the tower section 8.

[0096] FIG. 6 illustrates that a stud bolt 6 from the container 5, with a nut 7 mounted thereon, has been gripped by a gripping portion 3 of the bolt gripping tool 1, and is in the process of being moved away from the container 5 by operation of a moving portion 4 of the bolt gripping tool 1. It can be seen that the bolt gripping tool 1 is arranged next to the lower flange 9 of the tower section.

[0097] FIG. 7 is a view from above illustrating that stud bolts 6 are being gripped by means of the gripping portions 3 of the gripping tool 1 and moved by means of the moving portions 4 of the gripping tool 1 from the container 5 to through-going bolt holes 12 formed in the lower flange 9 of the tower section 8. The use of the bolt gripping tool 1 for this purpose minimises the amount of manual work required. It can be seen from the insert that the stud bolts 6 are positioned in the through-going bolt holes 12 of the lower flange 9 in such a manner that the nuts 7 is arranged above the lower flange 9, and thereby rest on the lower flange 9. Accordingly, the nuts 7 prevent the stud bolts 6 from passing all the way through the through-going bolt holes 12, i.e. they retain the stud bolts 6 relative to the lower flange 9.

[0098] FIG. 8 shows a portion of the lower flange 9 with stud bolts 6 arranged in each of the through-going bolt holes 12. It can be seen that the stud bolts 6 arranged in the through-going bolt holes 12 formed in a region of the lower flange 9 which rests on a tower support 2 have not been advanced through the through-going bolt holes 12 to the extent that the nuts 7 rest on the lower flange 9. Instead the ends of these stud bolts 6 rest on the tower support 2.

[0099] In FIG. 9 the tower section has been lifted clear of the tower supports 2. Thereby the stud bolts 6 which previously rested on the tower support 2, as illustrated in FIG. 8, have advanced further through the respective through-going bolt holes 12 to the extent that the nuts 7 now rest on the lower flange 9.

[0100] In FIG. 10 the tower section 8 has been lifted to a position immediately above another tower section 13. The stud bolts 6 positioned in each of the through-going bolt holes 12 of the lower flange 9 of the tower section 8 have been lifted along with the tower section 8. Accordingly, the tower section 8 and all bolts 6 required for mounting the tower section 8 on the other tower section 13 are lifted to the mounting position in a single lifting operation.

[0101] The tower section 8 is in the process of being lowered towards a mounting position on the other tower section 13 in order to arrange the lower flange 9 of the tower section 8 in abutment with an upper flange 14 of the other tower section 13. The upper flange 14 of the other tower section 13 is also provided with a plurality of through-going bolt holes 15. As the tower section 8 is lowered towards the other tower section 13, the stud bolts 6, which are already arranged in the through-going bolt holes 12 of the tower section 8, are advanced through the through-going bolt holes 15 of the upper flange 14 of the other tower section 13. Thereby a flange combination is formed.

[0102] FIG. 11 shows a part of the flange combination formed in the manner described above. It can be seen that the lower flange 9 of the tower section and the upper flange 14 of the other tower section are arranged in abutment with each other, and that each of the stud bolts 6 extends through a pair of through-going bolt holes 12, 15 formed in the lower flange 9 of the tower section and the upper flange 14 of the other tower section, respectively, and with the respective nuts 7 resting on the lower flange 9 of the tower section, i.e. the nuts 7 are arranged above the flange combination, and they retain the stud bolts 6 relative to the lower flange 9 of the tower section, and thereby relative to the flange combination.

[0103] A nut 7 is in the process of being mounted on a lower part of one of the stud bolts 6. This nut 7 is arranged below the upper flange 14 of the other tower section, and thereby below the flange combination.

[0104] FIG. 12 shows the nut 7 in position on the lower part of the stud bolt 6.

[0105] FIG. 13 illustrates adjustment of the position of one of the stud bolts 6 relative to the flange combination, using a socket tool 16 according to an embodiment according to the invention. The socket tool 16 comprises a body 17 formed with an inner cavity (not visible) in which a part of a stud bolt 6 can be received. The socket tool 16 is further provided with a tool engaging portion 18 in which a driving tool 19 is arranged. Operating the driving tool 19 causes the position of the stud bolt 6 relative to the flange combination to be adjusted in a manner which will be described in further detail below with reference to FIGS. 15 and 16.

[0106] As a result, the stud bolt 6 will be positioned relative to the flange combination in such a manner that the upper end of the stud bolt 6 is arranged with a specified distance to the lower flange 9 of the tower section. Subsequently, the socket tool 16 and the driving tool 19 may advantageously be moved to one of the other stud bolts 6 in order to adjust the position of that stud bolt 6 relative to the flange combination. This may be repeated until the position of each of the stud bolts 6 has been adjusted.

[0107] When the position of a given stud bolt 6 has been adjusted as described above, the nut 7 mounted on the lower part of the stud bolt 6 may advantageously be moved into abutment with the upper flange 14 of the other tower section.

[0108] FIG. 14 shows tensioning of one of the stud bolts 6 by rotating the nut 7 mounted thereon, using a hydraulic tensioning tool 20.

[0109] FIGS. 15 and 16 illustrate various steps during adjustment of the position of a stud bolt 6 relative to a flange combination, using a socket tool 16 according to an embodiment of the invention. Each of the illustrated stud bolts 6 represents a step of the process, in a sequence from left to right. FIG. 15 is a cross sectional view of the flange combination and the stud bolts 6, and FIG. 16 is a perspective cross sectional view.

[0110] Initially, the stud bolt 6, with a nut 7a mounted thereon, is arranged in the through-going bolt holes 12, 15 formed in the lower flange 9 of the tower section and the upper flange 14 of the other tower section, respectively, in the manner described above with reference to FIGS. 1-14. Accordingly, the nut 7a rests on the lower flange 9 of the tower section. Furthermore, an additional nut 7b is mounted above the nut 7a which rests on the lower flange 9. This nut 7b will be mounted on the lower part of the stud bolt 6 at a later point in time, but mounting it on the upper part of the stud bolt 6 as illustrated allows it to be lifted to the mounting position along with the tower section and the stud bolts 6, in the manner described above, i.e. a separate lifting operation for lifting the additional nuts 7b to the mounting position is not required.

[0111] Thus, in the next step the nut 7b has been removed from the upper part of the stud bolt 6 and has instead been mounted on the lower part of the stud bolt 6. The nut 7b has been mounted in such a manner that it is not arranged in abutment with the upper flange 14 of the other tower section, thereby allowing the stud bolt 6 to move in an upwards direction if this is required.

[0112] In the next step a socket tool 16 has been mounted on the upper end of the stud bolt 6. The socket tool 16 comprises a body 17 with an inner cavity 21. The inner cavity 21 has a threaded portion and an unthreaded portion, arranged adjacent to an open end of the inner cavity 21. The socket tool 16 has been mounted on the stud bolt 6 by sliding the unthreaded portion of the inner cavity 21 onto the upper end of the stud bolt 6.

[0113] The socket tool 16 further comprises an inner part 22 with an outer thread. The inner part 22 is arranged inside the inner cavity 21 in such a manner that the outer thread of the inner part 22 is arranged in threaded engagement with the threaded portion of the inner cavity 21. The inner part 22 is further provide with a tool engaging part 18 arranged to receive a tool, e.g. as illustrated in FIG. 13.

[0114] In the next step the socket tool 16 has been advanced further onto the stud bolt 6. This is obtained by rotating the inner part 22 by operating a driving tool (not shown) mounted on the tool engaging part 18. Due to the threaded connected between the inner part 22 and the inner cavity 21, this causes the body 17 to rotate, thereby forming a threaded connection between the threaded portion of the inner cavity 21 and the outer thread of the stud bolt 6. Accordingly, the socket tool 16 is screwed onto the upper end of the stud bolt 6, until the end of the inner part 22 abuts the end of the stud bolt 6, as shown.

[0115] In the next step rotation of the inner part 22 as described above is continued. However, since the end of the inner part 22 now abuts the upper end of the stud bolt 6, this causes the stud bolt 6 to be moved in a downwards direction, due to the threaded connection between the threaded portion of the inner cavity 21 and the stud bolt 6. This continues until the socket tool 16 abuts the nut 7a. At this point in time the upper end of the stud bolt 6 is arranged at a specific distance above the lower flange 9 of the tower section. This specific distance is defined by the distance between the end of the inner part 22 and the free end of the body 17, which is arranged in abutment with the nut 7a, and the size of the nut 7a. Accordingly, the position of the stud bolt 6 has been adjusted very precisely.

[0116] Furthermore, when the socket tool 16 has been moved into abutment with the nut 7a, the body 17 is prevented from rotating relative to the stud bolt 6.

[0117] In the next step the nut 7b is moved into abutment with the upper flange of the other tower section.

[0118] Finally, in the last step the socket tool 16 is removed from the stud bolt 6.

[0119] Reverse rotation of the inner part 22 causes the inner part 22 to rotate relative to the body 17 along a specified angular interval which is defined by grooves formed in the body 17, in which protruding parts formed on the inner part 22 are received. This will be described in further detail below with reference to FIGS. 17 and 18. This moves the inner part 22 slightly upwards relatively to the body 17, sufficiently to move the inner part 22 out of abutment with the stud bolt 6. Reverse rotation of the socket tool 16 continues until the socket tool is free of the stud bolt 6. Thereby the total time required for adjusting the position of all stud bolts 6 is minimised and the position is adjusted reliably.

[0120] FIGS. 17 and 18 are perspective views of a body 17 and an inner part 22, respectively, of a socket tool according to an embodiment of the invention. The inner part 22 of FIG. 18 is configured to be inserted into the body 17 of FIG. 17, thereby forming a socket tool. The socket tool formed in this manner could, e.g., be the socket tool illustrated in FIGS. 15 and 16.

[0121] The body 17 of FIG. 17 has a cylindrical shape defining an inner cavity 21. The body 17 is further provided with two through-going grooves 23 formed in the cylindrical wall of the body 17. Each groove 23 extends over an angular distance of substantially 90° along the circumference of the body 17, and the two grooves 23 are arranged substantially opposite to each other.

[0122] The inner part 22 of FIG. 18 also has a cylindrical shape which is sized to fit inside the inner cavity 21 of the body 17 illustrated in FIG. 17. The inner part 22 is provided with a tool engaging part 18 and two protruding parts 24 which protrude outwards from the surface on opposite sides of the cylindrical inner part 22.

[0123] When the inner part 22 of FIG. 18 is arranged inside the inner cavity 21 of the body 17 of FIG. 17, each of the protruding parts 24 is received in one of the through-going grooves 23. Thereby the inner part 22 is allowed to rotate relative to the body 17 along an angular span defined by the grooves 23, i.e. approximately 90°, corresponding to the protruding parts 24 moving from one end of the respective groove 23 to the opposite end.

[0124] Clockwise or counter clockwise rotation or of the inner part 22 will cause a corresponding rotation of the body 17 when the two protruding parts 24 are in their extreme positions in the grooves 23, whereas the inner part 22 and the body 17 may rotate relative to each other between the extreme positions of the two protruding parts 24.