METHOD FOR CORROSION PROTECTION IN A WIND TURBINE AND WIND TURBINE

Abstract

Provided is a method for corrosion protection in bolt holes of a wind turbine, whereby a sleeve made of a corrosion resistant metallic material is inserted into the bolt hole, in particular covering the whole length of the bolt hole wall, and at least partly expanded using an expander tool to be fixed in the bolt hole.

Claims

1. A method for corrosion protection in bolt holes of a wind turbine, comprising: inserting a sleeve made of a corrosion resistant metallic material into a bolt hole, covering a whole length of a bolt hole wall; and at least partly expanding the sleeve using an expander tool to be fixed in the bolt hole.

2. The method according to claim 1, wherein the corrosion resistant metallic material comprises aluminium and/or zinc.

3. The method according to claim 1, wherein the sleeve has a thickness of at least 1.2 mm.

4. The method according to claim 1, wherein the expander tool is a tube expander.

5. The method according to claim 1, wherein at least the end parts of the sleeves extending over at least 20% of the sleeve are expanded.

6. The method according to claim 5, wherein the sleeve is expanded over the whole length of the sleeve.

7. The method according to claim 1, wherein the sleeve protrudes from the bolt hole at at least one end to form a holding rim when the sleeve is expanded.

8. A wind turbine, comprising: a plurality of bolt holes for bolted connection between components, wherein at least a part of the bolt holes has a sleeve made of a corrosion resistant metallic material fixed therein by expanding using a method according to claim 1, and covering a whole length of the bolt holes.

9. The wind turbine according to claim 8, wherein the sleeved bolt holes are used for connecting blade bearings to a hub.

10. The wind turbine according to claim 8, wherein the bolt hole walls are made of steel and/or the wind turbine is an offshore wind turbine.

11. The method of claim 1, wherein the expanding tool is a pneumatic or electric roller machine.

Description

BRIEF DESCRIPTION

[0021] Some embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, where in:

[0022] FIG. 1 depicts a schematic drawing of a blade bearing of a wind turbine having bolt holes receiving bolts when fixing a wind turbine blade to the hub, in accordance with embodiments of the present invention;

[0023] FIG. 2 depicts a cross section of such a bolt hole, in accordance with embodiments of the present invention;

[0024] FIG. 3 depicts a sleeve, in accordance with embodiments of the present invention;

[0025] FIG. 4 depicts an expander tool, in accordance with embodiments of the present invention;

[0026] FIG. 5 depicts the sleeve of FIG. 3 inserted into the bolt hole and expanded using the expander tool, in accordance with embodiments of the present invention;

[0027] FIG. 6 depicts a final product, in accordance with embodiments of the present invention; and

[0028] FIG. 7 shows a detail of the connection area between blades and a hub in a wind turbine, in accordance with embodiments of the present invention.

DETAILED DESCRIPTION

[0029] FIGS. 1 to 6 show materials and illustrate certain steps of an embodiment of the method according to the embodiments of the invention. FIG. 1 shows a schematic drawing of a blade bearing 1 of a wind turbine having bolt holes 2 receiving bolts when fixing a wind turbine blade to the hub.

[0030] FIG. 2 shows a cross section of such a bolt hole 2. The bolt hole 2 is formed in steel 3 which thus also forms the bolt hole wall 4. Since the steel 3 is subject to corrosion, the present method aims at protecting the bolt hole wall 4 from corrosion effects caused by water or respective water spray. To achieve this protection, a sleeve 5 as shown in FIG. 3 is used. The sleeve 5 is made from a corrosion resistant metallic material 6, in particular comprising zinc or aluminium or an alloy containing at least one of these metals. The outer diameter of the cylindrical sleeve 5 matches the inner diameter of the bolt hole wall 4.

[0031] FIG. 4 shows a schematic of an expander tool 7, in this case a tube expander as known from the respective fields of the art, for example an electrical rolling machine. The expander tool 7 in FIG. 3 is only exemplary; in particular, any kind of suitable commercially available tube expander may be applied.

[0032] According to the method, as shown in FIG. 5, the sleeve 5 is inserted into the bolt hole 2 and expanded using the expander tool 7 to fix the sleeves 5 such that the metallic material 6 adheres to the bolt hole wall 4.

[0033] FIG. 6 shows the final product of this method. The whole wall 4 of the bolt hole 2 is covered by the sleeve 5, protecting the steel 3 from corrosion.

[0034] Optionally, the sleeve 5 may be chosen a bit longer than the length of the bolt hole 2 such that it protrudes over the bolt hole 2 at both ends, resulting in the forming of a holding rim 8 during the expanding process.

[0035] Finally, FIG. 7 shows a detail of a wind turbine according to the embodiments of the invention. The hub 9 and a root 10 of a blade of the wind turbine are connected using bolt connections, wherein bolts 11 extend through bolt holes 2. As can be seen from the section of FIG. 7, the corresponding bolt holes 2 each comprise a sleeve 5 inserted and fixed according to a method according to the embodiments of the invention.

[0036] 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.

[0037] 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.