Tower element with platform and fixation element

Abstract

There is presented a tower element, such as a tower element for a tower for a wind turbine generator, said tower element comprising a hollow, tubular element, a flange on an inside surface of the hollow, tubular shell, a unit comprising a platform and a fixation element, such as a plurality of fixation elements, attached to the platform, wherein the unit is arranged with respect to the flange, so that the flange prevents movement of the platform in both directions along an axis being parallel with an axis of the tubular element, and movement of the platform is allowed in at least one direction along an axis being orthogonal to the axis of the tubular element. There is furthermore presented a tower, a wind turbine generator and a method for providing a tower element.

Claims

1. A tower element for a tower of a wind turbine generator, comprising: a hollow, tubular element, a flange on an inside surface of the hollow, tubular element, a unit comprising: a platform, and at least one fixation element attached to the platform, the at least one fixation element being rotatable relative to the platform, wherein the unit is arranged with respect to the flange, so that: the flange prevents movement of the platform in both directions along an axis being parallel with an axis of the tubular element, and movement of the platform is allowed in at least one direction along an axis being orthogonal to the axis of the tubular element.

2. The tower element according to claim 1, wherein the unit abuts the flange at least at two points of contact including: a first point of contact where the flange inhibits movement of the unit in a first direction along an axis being parallel to the axis of the tubular element, and a second point of contact where the flange inhibits movement of the unit in a second direction along an axis being parallel to the axis of the tubular element, where the second direction is opposite the first direction, and where a vector formed by projecting a vector from the first point of contact to the second point of contact onto an axis of the hollow, tubular element, is parallel with the first direction.

3. The tower element according to claim 1, wherein the unit is arranged with respect to the flange, so that: the flange prevents movement of the platform in both directions along an axis being parallel with an axis of the tubular element, and movement of the platform is allowed in at least one direction along an axis being orthogonal to the axis of the tubular element, by: the unit being arranged relative to the hollow, tubular element so that the flange prevents relative movement of the unit with respect to the flange in a first direction along the axis of the tubular element, and so that the fixation element comprises a portion extending beyond the flange in the first direction, and the fixation element being rotated so that at least some of the portion extending beyond the flange in the first direction is arranged so that the flange prevents relative movement of the unit with respect to the flange in a second direction along the axis of the tubular element, where the second direction is opposite the first direction.

4. The tower element according to claim 3, wherein the fixation element being rotated so that at least some of the portion extending beyond the flange in the first direction is arranged so that the flange prevents relative movement of the unit with respect to the flange in a second direction along the axis of the tubular element, where the second direction is opposite the first direction, can be provided by: rotating the fixation element about a central axis of a member wherein the portion extending beyond the flange in the first direction, extends further away from the central axis of the member than another portion of the fixation element.

5. The tower element according to claim 4, wherein a horizontal dashed line separates a first portion of the fixation element within a first interval along the axis of the tubular element, and a second portion within a second interval along the axis of the tubular element, and the second portion extends beyond and further away from the central axis of the member than the first portion.

6. The tower element according to claim 1, wherein the unit and the flange are forming a sliding fit.

7. The tower element according to claim 1, wherein the unit comprises a bolt with an axis substantially parallel with the axis of the tubular element, which bolt intersects at least a surface of each of the fixation element and the platform and prevents relative, translational movement of the fixation element relative to the platform in directions orthogonal to the axis of the tubular element.

8. The tower element according to claim 7, wherein the fixation element comprises: a first portion within a first interval along the axis of the tubular element, which portion comprises no parts, which are further away from the bolt in a first radial direction (v.sub.1) away from the axis of the bolt, and away from the axis of the tubular element, than a first distance (d.sub.1), and a second portion within a second interval along the axis of the tubular element, wherein the first interval and the second interval are not overlapping, which portion comprises parts, which are further away from the bolt in the first radial direction, than a second distance (d.sub.2), where the second distance is larger than the first distance.

9. The tower element according to claim 8, wherein the first portion comprises parts, which are further away from the bolt in a second radial direction than a third distance, wherein the second radial direction is: away from the axis of the bolt, and within an angular interval of [0°, −90°] or [0°, 90°], around the axis of the bolt, with respect to the first angular direction, where the third distance is larger than the first distance.

10. The tower element according to claim 8, wherein the second portion comprises no parts, which are further away from the bolt in a third radial direction than a fourth distance, wherein the third radial direction is: away from the axis of the bolt, and different with respect to the first radial direction, where the fourth distance is smaller than the second distance.

11. The tower element according to claim 7, wherein the platform has a hole for accommodating the bolt, said hole being delimited around its axis by a wall, and wherein a resilient member is arranged between the bolt and the wall, so as to exert a force upon the bolt and keeping it in place in the absence of application of a force on the bolt exceeding a threshold force.

12. The tower element according to claim 1, wherein the flange is encircling the axis of the hollow, tubular element.

13. The tower element according to claim 1, wherein the flange is placed between ends of the hollow, tubular element and placed away from each end with respect to an axis being parallel with the axis of the hollow, tubular element.

14. A wind turbine tower comprising one or more tower elements according to claim 1.

15. A wind turbine comprising the tower according to claim 14.

16. A method for providing a tower element for a tower of a wind turbine generator, said method comprising providing: a hollow, tubular element, a flange on an inside surface of the hollow, tubular element, a unit comprising: a platform, at least one fixation element attached to the platform, the at least one fixation element being rotatable relative to the platform, said method further comprising: arranging the unit relative to the hollow, tubular element so that the flange prevents relative movement of the unit with respect to the flange in a first direction along the axis of the tubular element, and so that the fixation element comprises a portion extending beyond the flange in the first direction, rotating the fixation element relative to the platform so that at least some of the portion extending beyond the flange in the first direction is arranged so that the flange prevents relative movement of the unit with respect to the flange in a second direction along the axis of the tubular element, where the second direction is opposite the first direction, and fixing the fixation element relative to the platform so as to fix the fixation element in a position wherein: the flange prevents movement of the platform in both directions along an axis being parallel with an axis of the tubular element, and movement of the platform is allowed in at least one direction along an axis being orthogonal to the axis of the tubular element.

17. The method according to claim 16 for providing a tower element, wherein fixing the fixation element relative to the platform so as to prevent movement of the platform in both directions along an axis being parallel with an axis of the tubular element, is carried out by; rotating the fixation element into an angular position where further rotation is blocked by a part of the fixation element being blocked by contact forces upon abutting the flange and thereby subsequently passively applying an oppositely directed torque to the fixation element, and rotating a bolt by actively applying a torque to a bolt on one side of the platform.

18. The method according to claim 16 for providing a tower element, wherein fixing the fixation element relative to the platform so as to prevent movement of the platform in both directions along an axis being parallel with an axis of the tubular element, is carried out while an axis of the tubular element is non-vertical.

19. The method according to claim 16 for providing a tower element, wherein: providing the unit comprises: fixing a plurality of fixation elements to the platform, wherein each fixation element is fixed to the platform via a bolt so that rotation of the fixation element around the axis of the bolt requires overcoming a threshold torque, which exceeds a torque applied by gravity around the axis of the bolt, wherein the step of rotating the fixation element comprises: applying to the bolt an applied torque above the threshold torque thereby rotating bolt and fixation element.

20. The method according to claim 16, wherein the method comprises providing the tower element in an orientation wherein the axis of the hollow, tubular element is substantially horizontal and subsequently placing a buffer element between the platform and the hollow, tubular element.

21. The method according to claim 16, wherein providing a flange on an inside surface of the hollow, tubular element, comprises attaching the flange to the inside surface of the hollow, tubular element.

22. The method according to claim 16, wherein the tower element is transported subsequent to fixing the fixation element relative to the platform so as to prevent movement of the platform in both directions along an axis being parallel with an axis of the tubular element.

23. The method according to claim 16, wherein rotating the fixation element so that at least some of the portion extending beyond the flange in the first direction is arranged so that the flange prevents relative movement of the unit with respect to the flange in a second direction along the axis of the tubular element, is provided by; rotating the fixation element about a central axis of a member wherein the portion extending beyond the flange in the first direction extends further away from the central axis of the member than another portion of the fixation element.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The tower element and corresponding tower, wind turbine and method for providing a tower element according to the invention will now be described in more detail with regard to the accompanying figures. The figures show one way of implementing the present invention and is not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

(2) FIG. 1 shows a wind turbine 100.

(3) FIG. 2 shows technical drawings of the fixation element 210.

(4) FIG. 3 shows a part of the unit 320 with fixation element 310 attached to the platform 322.

(5) FIG. 4 shows a part of a tower element 430.

(6) FIG. 5 illustrates directions and distances of the fixation element,

(7) FIG. 6 illustrates a method according to an embodiment of the invention, FIG. 7 shows perspective views of the fixation element.

(8) FIG. 8 shows a part of a tower element.

(9) FIG. 9 shows parts of a tower element and adjacent elements.

(10) FIG. 10 shows is a schematic illustrating assembly of the unit.

DETAILED DESCRIPTION OF AN EMBODIMENT

(11) FIG. 1 shows a wind turbine 100 (which may also be referred to as a wind turbine generator (WTG)) comprising a tower 101 and a rotor 102 with at least one rotor blade 103, such as three blades and a nacelle 104. The tower 101 comprises a plurality of hollow, tubular elements, such as hollow, tubular element 106 indicated between the dashed horizontal lines.

(12) FIG. 2 shows technical drawings of the fixation element 210. In the top of the drawing (a) there is shown a side view, such a observed in a direction orthogonal to the axis of the tubular element and the bolt, wherein an upwards direction in the drawing is a direction towards the flange and the platform. A dimension 211 (“height”) in the axial direction is indicated. In the bottom of the drawing (b) there is shown a top view, such as observed in a direction parallel with to the axis of the tubular element and the bolt, and more particularly in a direction from (or through) the platform and the flange. The figure shows a hole for the bolt.

(13) FIG. 3 shows a part of the unit 320 with fixation element 310 attached to the platform 322 via a bolt, or other similar member (not shown). The fixation element comprises a polymeric part 312 and a metallic, hollow, circular cylindrical insert 314 (such as a nut) for engaging with the bolt, which has axis 316, illustrated as a central axis. The fixation element has a through-going hole for accommodating the bolt. In one embodiment, the opening in the polymeric part below the insert 314 has a smaller inner diameter than the outer diameter of the bolt, so that when the bolt is tightened it cuts its way through the polymer ensuring a tight fit. The platform 322 comprises a plate 324 and a nut 326 welded to the plate for engagement with the bolt. The platform furthermore is arranged with a groove, and the unit comprises a resilient member, such as a spring or rubber band 328, in the groove for engaging with the bolt and keeping it in place during transport and installation. The horizontal dashed line 318 separates a first portion of the fixation element (above the dashed line 318) within a first interval along the axis of the tubular element (which is parallel with the axis 316 of the bolt), and a second portion within a second interval along the axis of the tubular element. The right hand side of the second portion extends beyond (further away from the axis of the bolt) than the first portion. The upper surface of the right hand portion may be non-horizontal, and in this embodiment it tilts slightly upwards. In other embodiments, it tilts slightly downwards.

(14) FIG. 4 shows a part of a tower element 430 comprising a hollow, tubular element 436, a flange 434 attached, such as welded, to the tubular element 436, and the unit 310 of FIG. 3 attached to the flange 434 via a bolt 432. The figure shows that the plate 324 of the platform 322 abuts a buffer element in the form of a flexible, rubber tube 435, which in turn abuts the tubular element 436. Relative movement between the unit 320 and the tubular element 436 is allowed as indicated by the double-headed arrow 438, although at some point upon compressing the buffer element 435, movement towards each other is no longer possible. The figure shows that the plate 324 of the platform 322 abuts the flange 434 at a first point at an upper side of the flange 434 and the polymeric part of the fixation element 310 abuts the flange at a second point at an opposite side of the flange 434 with respect to an axial direction (i.e., on either side of a plane orthogonal to the axial direction). The bolt is shown fully traversing each of the platform and the fixation element through through-going holes in each of the platform and the fixation element. In alternative embodiments, each or both of the holes for the bolt in the platform and the fixation element are non-through-going. For example, the hole in the platform may be a non-through-going hole realized by not having a hole in the plate 324 but merely having the hole arranged as the hole in the nut 326, which might be advantageous for rendering the need for alignment between the hole in the plate and the nut superfluous.

(15) FIG. 5 illustrates directions and distances of the fixation element, and more particularly a first radial direction given by the direction of a first vector (v.sub.1), a first distance (d.sub.1), a second distance (d.sub.2), a second radial direction given by the direction of a first vector (v.sub.2), a third distance (d.sub.3), a third radial direction is given by the direction of a first vector (v.sub.3) and a fourth distance (d.sub.4). The part around the axis (see also perspective view in FIG. 7) is shown as being circularly cylindrical with radius d.sub.4. In other embodiments, this part is not circular cylindrical (as observed in the top view similar to FIG. 2(b) and FIG. 5), but may for example be elliptical. In such other embodiments, a size of that part in a direction from the axis of the bolt in a direction of the flange may decrease during rotation during mounting (see also FIGS. 6(a)-(c)), so that initially (cf., e.g., FIG. 6(a) a size in a direction of the flange is relatively larger than said distance upon rotation (cf., e.g., FIG. 6(b)-(c)). An advantage of such decrease in distance may be that the fixation element may be arranged to abut the flange initially (cf. FIG. 6(a)), but then during rotation the surface of said part is due to the non-circularity moved away from the flange and further contact is avoided, which may for example be beneficial for reducing or eliminating friction during rotation.

(16) FIG. 6 illustrates a method according to an embodiment of the invention, where the method is illustrated by three snapshots (a)-(c) at different points in time during installation. Each snapshot is a top view as observed in an axial direction, such as from a top of the hollow, tubular element. The fixation element is mounted on the platform (not shown). The flange is indicated by the thick, dashed line, which is an edge of the flange, where the flange is on the right hand side. In the first shapshot (a) the unit with the fixation element in a first angular orientation around the axis of the bolt is being moved in an axial direction (such as along an axis orthogonal to the plane of the paper) and the fixation, so that at least a part of the fixation element is moved past the axial position of the flange and so that at least a part of the unit, such as the platform is brought to abut the flange so that the flange prevents further movement of the unit in that axial direction. In the next shapshot (b) the unit is abutting the flange at the first point of contact and the fixation element is rotated around the axis of the bolt by rotating the bolt in a tightening direction so that the unit has parts on both sides of the flange in an axial direction. In the last snapshot (c) the fixation element is rotated into its final position by continued rotating the bolt where after the unit is tightened and fixed onto the flange by further rotating the bolt. It is understood that the flange is sandwiched between parts of the unit, for example so that a fictitious line in an axial direction may intersect first the platform, then the flange and finally the fixation element. The flange thus fixes the position of the unit in the axial direction, but it allows movement in directions orthogonal to the axial direction.

(17) FIG. 7 shows a perspective view of the fixation element, which is also shown in FIGS. 2, 5 and 6.

(18) FIG. 8 shows a part of a tower element similar to FIG. 4 except that the platform, fixation unit and bolt are arranged so that no part of the bolt extends further in one axial direction, such as the direction opposite the fixation element, than the platform. This may be preferred for safety reasons as no bolt head sticks above the level of the platform, which may in turn reduce a risk of tripping.

(19) FIG. 9 shows parts of a tower element 430 (as in FIG. 4) and adjacent elements, in particular an adjacent (upper) tower element 944 and an adjacent (lower) foundation 948. The flange 434 is understood to be spaced apart with respect to each end of the hollow, tubular element 436, such as a smallest distance with respect to an end of the hollow, tubular element (such as the smallest distance amongst a first distance 952 from the (closest part of the) flange 434 to a first (top) end of the hollow, tubular element 436 and a second distance 954 from the (closest part of the) flange 434 to a second (bottom) end of the hollow, tubular element 436) being at least a certain non-zero percentage of a total length 950 of the hollow tubular element along an axis of the hollow, tubular element and/or such as a certain non-zero distance. The flange 434 is not being an end-flange of the hollow, tubular element, such as wherein an end flange, may be a lower end-flange 940 or an upper end-flange 942. The adjacent (upper) tower element 944 is coupled to the tower element 436 via flanges 942, 946. The tower element 436 is coupled to the adjacent (lower) foundation 948 via the lower end-flange 940. A lower end of the tower element 436 may be flush with a plane 956 being equal to or above a ground level and/or a sea level.

(20) FIG. 10 shows is a schematic illustrating assembly of the unit. The flange 1034 is a monolithic element. The flange 1034 is completely encircling (360°) and forming a closed loop around the axis 1058 of the hollow, tubular element 1036. A cross-section of the flange 1034 in a plane comprising the axis 1058 of the hollow, tubular element 1036, is circularly symmetrical. The left-hand side (a) of FIG. 10 furthermore shows a part of a process of arranging the unit 1020 relative to the hollow, tubular element 1036, where the arrow 1060 indicates a direction of movement relative to the hollow, tubular element 1036 and flange 1034 in a direction along an axis being parallel with the axis 1058 of the tubular element 1036. The right-hand side (b) of FIG. 10 furthermore shows the unit 1020 being placed relative to the hollow, tubular element 1036 and flange 1034, so that the flange prevents further movement of the platform in the direction indicated with arrow 1060 and wherein the prevented further movement is indicated by arrow 1062 with the overlaid “no” symbol. In FIG. 10, the tubular element 1036 is shown with the axis 1058 being vertical, but it could have been any orientation, such as horizontal, i.e., during installation of assembly and/or transportation, the axis 1058 could be any orientation. When placed in a tower, the orientation of axis 1058 is substantially vertical, such as vertical. Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms “comprising” or “comprises” do not exclude other possible elements or steps. Also, the mentioning of references such as “a” or “an” etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.