U.S. patent application number 13/109222 was filed with the patent office on 2011-11-24 for blade of a wind turbine.
Invention is credited to Jens Jorgen Ostergaard Kristensen, Michael Noerlem.
Application Number | 20110286853 13/109222 |
Document ID | / |
Family ID | 42651050 |
Filed Date | 2011-11-24 |
United States Patent
Application |
20110286853 |
Kind Code |
A1 |
Kristensen; Jens Jorgen Ostergaard
; et al. |
November 24, 2011 |
BLADE OF A WIND TURBINE
Abstract
A blade of a wind turbine is provided. The blade includes
different layers, which are used to build up the three-dimensional
shape of the blade. Resin is applied to connect the layers while
the blade is manufactured. A reinforcement structure is arranged
close to the surface of the blade and at a resin-rich-section of
the blade, where a certain amount of resin is gathered during the
manufacture of the blade.
Inventors: |
Kristensen; Jens Jorgen
Ostergaard; (Nibe, DK) ; Noerlem; Michael;
(Svenstrup, DE) |
Family ID: |
42651050 |
Appl. No.: |
13/109222 |
Filed: |
May 17, 2011 |
Current U.S.
Class: |
416/229R |
Current CPC
Class: |
Y02P 70/50 20151101;
B32B 2260/046 20130101; B32B 2260/023 20130101; B32B 21/042
20130101; Y02P 70/523 20151101; B32B 2603/00 20130101; B32B 21/045
20130101; B32B 2260/048 20130101; B32B 1/00 20130101; F05B
2280/6015 20130101; Y02E 10/721 20130101; B32B 5/26 20130101; F05C
2253/22 20130101; F05B 2280/702 20130101; Y02E 10/72 20130101; F05C
2253/20 20130101; B29L 2031/085 20130101; B32B 2260/026 20130101;
F03D 1/065 20130101; B32B 3/08 20130101 |
Class at
Publication: |
416/229.R |
International
Class: |
F01D 5/14 20060101
F01D005/14 |
Foreign Application Data
Date |
Code |
Application Number |
May 21, 2010 |
EP |
EP10163580 |
Claims
1.-10. (canceled)
11. A blade of a wind turbine, comprising: a plurality of different
layers, which are used to build up a three-dimensional shape of the
blade; and a reinforcement structure, which is arranged close to a
surface of the blade and at a resin-rich-section of the blade,
wherein resin is applied to connect the plurality of layers while
the blade is manufactured, and wherein a certain amount of resin is
gathered at the reinforcement structure during the manufacture of
the blade.
12. The blade according to claim 11, wherein the reinforcement
structure is arranged along at least a part of the trailing edge,
and wherein the reinforcement structure is arranged along at least
a part of the leading edge, and wherein the reinforcement structure
is arranged close to a plurality of sharp corners of the blade.
13. The blade according to claim 11, wherein the reinforcement
structure is arranged along at least a part of the trailing
edge.
14. The blade according to claim 11, wherein the reinforcement
structure is arranged along at least a part of the leading
edge.
15. The blade according to claim 11, wherein the reinforcement
structure is arranged close to a plurality of sharp corners of the
blade.
16. The blade according to claim 11, wherein the blade is
manufactured by an applied Vacuum Assisted Resin Transfer Moulding
process, which uses a closed-mould-structure to encapsulate the
blade while the resin is applied.
17. The blade according to claim 16, wherein the resin-rich-section
is defined by an inner surface of the closed-mould-structure and by
the shape of the blade.
18. The blade according to claim 11, where the reinforcement
structure is a rail.
19. The blade according to claim 11, wherein the reinforcement
structure includes an angle in its cross section, while the angle
is chosen in a way that the reinforcement structure is attached in
a form-fit-manner to the plurality of layers of the blade.
20. The blade according to claim 19, wherein the angle is
90.degree..
21. The blade according to claim 11, wherein the reinforcement
structure is a laminate structure and a pre-casted laminate
structure.
22. The blade according to claim 11, wherein the reinforcement
structure is a laminate structure.
23. The blade according to claim 11, wherein the reinforcement
structure is a pre-casted laminate structure.
24. The blade according to claim 11, wherein the reinforcement
structure comprises a plurality of channels or tubes, and wherein
the applied resin penetrates the reinforcement structure.
25. The blade according to claim 11, wherein the reinforcement
structure is an integrated part of the blade.
26. The blade according to claim 24, wherein the reinforcement
structure is an integrated part of the blade.
27. The blade according to claim 26, wherein the reinforcement
structure is arranged close to a surface of the blade.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority of European Patent Office
application No. 10163580.3 EP filed May 21, 2010, which is
incorporated by reference herein in its entirety.
FIELD OF INVENTION
[0002] The invention relates to a blade of a wind turbine
BACKGROUND OF INVENTION
[0003] Modern blades of a wind turbine are manufactured typically
by help of the so called "Vacuum Assisted Resin Transfer Moulding,
VARTM" process.
[0004] For this process a number of layers, which contain fibers,
mats, balsa-wood, prefabricated components, balloons filled with
any kind of shaping material, . . . , etc. is put onto a so called
"lower mould" to build up the three-dimensional shape of the blade.
The lower mould is used to support the "sandwich structure" of the
blade.
[0005] The lower mould is connected with an "upper mould" to form a
closed mould structure. The moulds enclose or better encapsulate
the blade structure.
[0006] During the VARTM-process a technical vacuum is applied to
the closed mould structure, thus air is evacuated out from this
structure while resin is infused into the structure
accordingly.
[0007] The resin is allowed to cure out and the blade can be
removed from the dismounted moulds.
[0008] The VARTM-process allows the production of very strong
blades and of very strong composites and components.
[0009] The composites and components may be designed and
constructed to be located inside a blade later, while the blade is
manufactured in a subsequent VARTM-process.
[0010] The products, which are manufactured by help of the
VARTM-process, even show a reduced weight due to the balsa-wood and
due to balloons used. The balloons stay inside the product while it
is manufactured, but will be removed later, thus a kind of an
air-filled cavity remains inside the product.
[0011] The most part of the product, especially of the manufactured
blade, is built up reinforcing materials, especially by
glass-fibers, carbon fibers, woven mats, etc.
[0012] Within this VARTM-process a problem arises. The closed mould
system may contain deep and concave-shaped cross-sections and
areas, which are needed to build up the specific and needed shape
of the product.
[0013] For example the trailing edge and/or the leading edge belong
to those sections.
[0014] Fiber mats, which are used to build up the shape of the
section, may not be aligned close and firm to an intended surface
of the blade. The intended surface is determined by the curvature
of the inner surface of the later closed mould system.
[0015] During the build-up process of the blade the fiber mats
might follow a curvature which is different to the intended one.
For example the fiber mats may tend to a shape like catenaries
(hanging chain) in certain circumstances.
[0016] This effect results in a number of voids, which are located
between the inner surface of the closed mould system and the fiber
mats. Due to the VARTM process the voids will be filled with
resin.
[0017] In this case the weight of the blade is increased due to the
weight of the resin, while the structure of the blade might be
weakened by the resin, as the resin shows no inner support
structure (fibers) at theses locations. Cracks may be the result on
the blade surface.
[0018] The wind turbine blade is exposed to fatigue load, thus the
leading edge and the trailing edge of the blade may show
fatigue-cracks in the blade surface.
[0019] Cracks need to be repaired by hand. This work is time
consuming and expensive.
SUMMARY OF INVENTION
[0020] It is therefore the aim of the invention, to provide an
improved wind turbine blade to overcome the problems mentioned
above.
[0021] This aim is reached by the features of the claims.
[0022] Preferred embodiments of the invention are object of the
dependent claims.
[0023] According to the invention the blade of a wind turbine
contains different layers, which are used to build up the
three-dimensional shape of the blade. Resin is applied to connect
the layers while the blade is manufactured. A reinforcement
structure is arranged close to the surface of the blade and at a
resin-rich-section of the blade, where a certain amount of resin is
gathered during the manufacture of the blade.
[0024] According to the invention the reinforcement structure is a
shaped and preferably open laminate, which is arranged at sections
of the blade, where a big amount of resin will usually arise, for
example during an applied VARTM process.
[0025] These sections contain sharp corners of the blade for
example, like the trailing edge or like the leading-edge of the
blade.
[0026] Due to the invention the production of the blade is cheaper,
as the number of cracks are minimized or even avoided due to the
reinforcement structure. Thus the repair-work is reduced or even
avoided.
[0027] Due to the invention the weight of the blade is reduced as
the number of resin-filled-voids is even reduced.
[0028] Due to the invention the blade structure, especially the
leading and the trailing edge, is stronger. Resin-rich areas are
supported by the reinforcement structure, which is an integrated
part of the blade.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] The invention is shown in more detail by help of figures
now.
[0030] The figures show preferred embodiments and do not limit the
scope of the invention.
[0031] FIG. 1 shows the arrangement invented by help of a
cross-sectional view to a closed-mould-system,
[0032] FIG. 2 shows the shape of the "open grid laminate", which is
used and described in FIG. 1.
[0033] FIG. 1 shows the arrangement invented by help of a
cross-sectional view to a part of a closed-mould-system. CMS.
[0034] A lower mould LM is used within a VARTM-process to support
the blade BL of a wind turbine.
[0035] The structure of the blade BL is built up by fibers, mats,
balsa-wood, prefabricated components, balloons filled with any kind
of shaping material, . . . , etc. (not shown here in detail) as
described above. Thus these elements form different layers of the
wind turbine blade.
[0036] Thus the lower mould LM is used to support this "sandwich
structure" of the blade BL.
[0037] An upper mould UM is connected with the lower mould LM and
is also used to build up the closed-mould-structure as described
above.
[0038] The cross sectional view shows the trailing edge TE of the
blade BL.
[0039] Due to the inner surface IS of the closed-mould-structure
and due to the specific shape of the trailing edge TE a resin rich
area RRA will be created.
[0040] If no further steps are taken the VARTM-process would lead
to cracks, as described above and will lead to voids. The voids
might be located between the inner surface IS of the closed mould
structure and the surface of the blade BL (or better and the
fiber-mat-surface of the blade BL) along the trailing edge TE.
[0041] To overcome these problems a shaped laminate structure SLS
is used as reinforcement structure. It is located along the
trailing edge TE and within the resin rich area RRA.
[0042] Preferably the shaped laminate structure SLS is shaped like
a rail, showing an angle in its cross section.
[0043] The angle is chosen in a way that the shaped laminate
structure SLS, used as reinforcement structure, is attached in a
form-fit-manner to the layers of the blade.
[0044] The angle might be a right angle with 90.degree., for
example.
[0045] Preferably the shaped laminate structure SLS is made as an
open structure, like a grid. This allows that resin penetrates the
laminate structure SLS during the VARTM process.
[0046] When the VARTM process is applied and when the blade BL is
finished the shaped laminate structure SLS is an integrated part of
the blade BL.
[0047] As the resin gets inside the shaped laminate structure SLS
it is used as a reinforcement-structure inside the blade BL.
[0048] Preferably the shaped laminate structure SLS is made as
pre-casted open structure. The pre-casted structure is integrated
and fixed by the resin within the blade BL.
[0049] The arrangement invented minimizes the need for
post-repairs. Additionally the manual work during the lay-up
process of the blade elements (fiber, mats, wood, etc.) is easier
than before as the "hanging chain" effect as described above is
reduced.
[0050] Thus an easier and simplified lay-up of the fiber material
at sharp corners of the blade is allowed. It is even possible to
implement and to achieve more difficult curvatures for the shape of
the blade.
[0051] Preferably the shaped laminate structure SLS is arranged
close to the surface of the blade BL.
[0052] The shaped laminate structure SLS is used as an
edge-protection, especially for the trailing edge and/or for the
leading edge or other relevant sections of the blade BL.
[0053] FIG. 2 shows the shape of an open grid laminate OGL, which
is used as shaped laminate structure SLS according to FIG. 1.
* * * * *