U.S. patent application number 13/144347 was filed with the patent office on 2011-11-10 for wind turbine blade.
Invention is credited to Manuel Torrez Martinez.
Application Number | 20110274552 13/144347 |
Document ID | / |
Family ID | 42312603 |
Filed Date | 2011-11-10 |
United States Patent
Application |
20110274552 |
Kind Code |
A1 |
Torrez Martinez; Manuel |
November 10, 2011 |
WIND TURBINE BLADE
Abstract
The invention relates to a wind turbine blade formed by outer
lateral skins (1) arranged on stringers (2) in the manner of inner
longitudinal partitions, the blade root being determined by a
cylindrical section (5) which is formed by means of extensions (4)
of the outer lateral skins (1) and the stringers (2) forming the
structural assembly of the blade body, said blade body being able
to be determined by means of longitudinal sections which are
attached to anchoring rods through longitudinal holes of the walls
of the sections in coinciding portions of the attachment.
Inventors: |
Torrez Martinez; Manuel;
(Pamplona, ES) |
Family ID: |
42312603 |
Appl. No.: |
13/144347 |
Filed: |
January 15, 2010 |
PCT Filed: |
January 15, 2010 |
PCT NO: |
PCT/ES2010/000008 |
371 Date: |
July 13, 2011 |
Current U.S.
Class: |
416/227A |
Current CPC
Class: |
F05B 2240/302 20130101;
F05B 2240/301 20130101; F03D 1/0675 20130101; Y02E 10/72 20130101;
Y02E 10/721 20130101 |
Class at
Publication: |
416/227.A |
International
Class: |
F01D 5/14 20060101
F01D005/14 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 19, 2009 |
ES |
P200900127 |
Claims
1. A wind turbine blade of the type comprising a structural
formation formed by outer lateral skins (1) arranged on an inner
structure formed by stringers (2) in the manner of longitudinal
partitions, the length of the blade being able to be determined by
means of the attachment of consecutive sections (7, 8),
characterized in that at the end corresponding to the base of the
blade the outer lateral skins (1) and the stringers (2) of the
inner structure determine extensions (4), by means of which a
cylindrical section (5) forming the blade root for the securing in
the assembly of application is formed; whereas the attachment of
the sections (7, 8) of longitudinal composition of the blade is
established with an anchoring by means of rods (15) which are
included through opposite longitudinal holes (11) of the respective
sections (7, 8), said rods (15) being attached in a threaded
coupling at one end on elements (14) which are fitted in cavities
(12) of one of the sections (7) which are attached, whereas at the
other end these rods (15) emerge in cavities (13) of the other
section (8) participating in the attachment, nuts (17) being
incorporated in these cavities (13) on the end of the rods (15),
which nuts allow performing a tightening for frontally compressing
the sections (7, 8) against one another.
2. The wind turbine blade according to claim 1, characterized in
that the extensions (4) making up the cylindrical section (5)
forming the root are determined with beveled or stepped-cut lateral
edges (6) for the attachment by means of the bonding of the
mentioned extensions (4) at said lateral edges (6)
3. The wind turbine blade according to claim 1, characterized in
that the cavities (12 and 13) into which the longitudinal holes
(11) for housing the rods (15) open out are made perpendicularly
over the inner portion of the structural wall of the sections (7,
8), without affecting the outer surface.
4. The wind turbine blade according to claim 3, characterized in
that the structural wall of the sections (7, 8) determines in the
attachment area a thickened portion (10), in which the longitudinal
holes (11) and the corresponding cavities (12, 13) are defined.
5. The wind turbine blade according to claim 1, characterized in
that in the coupling for the attachment between the sections (7, 8)
of longitudinal composition of the blade there is included an
intermediate ring (9) having, on its front faces, channels (9.1) in
which the outer lateral skins (1) and the stringers (2) of the
sections (7, 8) are fitted with their end edges.
Description
FIELD OF THE ART
[0001] The present invention relates to wind turbine blades which
are formed by the attachment of a set of independently manufactured
longitudinal parts, determining structural features of the assembly
for forming the blade which provide an advantageous implementation
in the part of the root intended to secure the blade on the
rotating hub in the corresponding wind turbine; likewise
contemplating a particular system for the attachment between
longitudinal sections of composition of the blade.
STATE OF THE ART
[0002] The worldwide demand for renewable energies, to deal with
climate change and to maintain an expectation of energy production
with less dependence on depletable natural resources, involves in a
highly relevant manner wind energy, which is mostly developed by
means of wind turbines which are driven by a rotor with blades
which captures the action of the wind.
[0003] The development of wind turbines and their application to
electricity production requires, however, wind turbines with an
increasingly higher rated power and lower cost per Kilowatt of the
energy which is produced.
[0004] To that end, the sweep surface of the blades of the rotor
receiving the action of the wind, among other aspects, is essential
in said wind turbines, such that one of the factors for maintaining
the energy generation power is the increase in the size of the
blades capturing the action of the wind.
[0005] Exceeding a measurement of the size of the blades of the
wind turbines entails, however, a series of associated problems due
to the difficulties which arise for the construction and the
assembly in the installation, as well as for the transport.
[0006] Indeed, the wind turbine blades of a great length (greater
than 35 meters) have a weight which greatly hinders the handling
and which furthermore conditions the need for a very resistant
anchoring in the installation, also having difficulties for the
transport, since special means are required which are very
expensive.
[0007] In relation to the installation securing, various anchoring
solutions have been developed, as well as structural
implementations for determining in the blade root a resistance
which allows safely withstanding all the stresses which that area
must withstand in the functional action of the blade. However, the
solutions developed in this sense detrimentally condition the
constructive formation and the cost of the blade to achieve
satisfactory results of resistance in the installation.
[0008] In addition, to solve the problems inherent to the
longitudinal dimension, the constructive implementation of the
blades by means of longitudinal sections is known, which sections
can be independently transported for their attachment in the site
of installation of the wind turbine and even in the constructive
assembly thereof.
[0009] This involves an advantage for blades of a great length
(between 40 and 60 meters) which are already demanded by the wind
energy sector, but also for more traditional blades (of between 30
and 40 meters), because since the blades can be made in sections of
between 15 and 20 meters in length, they can be transported by
normal means, a reduction of the transport cost being achieved
which is advantageously greater than the cost of forming the
independent sections and attaching them in the constructive
assembly of the blades.
[0010] In this sense, various systems have been developed for
attaching the component sections of the blades which are formed by
the attachment of longitudinal sections, such as the solution of
Patent ES 9901177, but the solutions known in such sense generally
have deficiencies relating to the assembling difficulty and to the
anchoring efficiency in the attachment of the sections.
OBJECT OF THE INVENTION
[0011] According to the invention, a wind turbine blade is
proposed, with a structural implementation which advantageously
determines a resistant root for securing the blade in its assembly
of application and which can furthermore be formed by means of
longitudinal sections, with also advantageous features of the
attachment between the sections.
[0012] This blade object of the invention essentially consists of
outer lateral skins laminated with layers of synthetic fibers, by
means of which the aerodynamic profile of the blade is determined,
arranged on a resistant inner structure formed by stringers in the
manner of longitudinal partitions, the trailing edge of the
aerodynamic profile being able to be determined by means of an
attachment between the outer skins themselves, whereas the leading
edge is formed by means of a complementary part also laminated with
synthetic fibers.
[0013] According to the invention, the outer lateral skins of the
aerodynamic profile and the stringers of the inner structure are
extended at the end of the base of the blade, determining between
the extensions of said parts a section of cylindrical composition
which forms the blade root for the securing in the assembly of
application.
[0014] The blade root is thus formed by the actual assembly of the
constructive formation of the blade, therefore being a simple
construction since it is not necessary to incorporate any accessory
part for determining the blade root and, furthermore, since the
root is formed by the actual structural parts of the constructive
composition of the blade body, without accessory parts, attachments
which can cause the weakening of the structural resistance of the
blade are prevented.
[0015] In addition, the blade can be formed by means of
longitudinal sections, a ring being arranged in the attachment of
the component sections, which ring determines at its front portions
channels in which there are fitted with their end edge the
stringers of the inner structure of the sections, as well as the
edges of the outer skins, which in the area comprised between the
inner stringers are formed with a inwardly thickened portion,
inside which, as well as over the stringers themselves, there are
defined longitudinal holes opening out into respective cavities of
the corresponding walls, the anchoring of the attachment being
performed by means of rods which are inserted through said
longitudinal holes, passing through the intermediate ring of the
attachment, which rods are attached in a threaded coupling with
respect to end elements between which a tightening tension is
established.
[0016] In the sections which are attached, the cavities into which
the longitudinal holes open out are made perpendicularly from the
inner portion of the corresponding walls, without passing to the
outer portion, said cavities having a cylindrical shape in one of
the sections which are attached, in order to fit a cylindrical
element therein, with respect to which the respective anchoring rod
is coupled by screwing, whereas in the other section the cavities
are oblong, a nut being incorporated therein on the end of the
anchoring rod, to perform through the opening of the oblong cavity
the action of the actuation on said nut.
[0017] An anchoring between the component sections of the blades is
thus obtained which allows establishing a resistant attachment,
with precision in the tightening by means of the actuation of the
nuts which are arranged on the anchoring rods, it being very easy
to assemble the attachment since the anchoring rods are
incorporated before the coupling in one of the sections to be
attached, such that it is then only necessary to couple the second
section and tighten the nuts on the anchoring rods.
[0018] The incorporation of the intermediate ring of the attachment
furthermore determines a protection preventing the defibration of
the layers of fibers in the attachment edge of the outer skins of
the blade sections which are attached, which prevents the force of
the wind from causing a progressive defibration deterioration of
the skins forming the aerodynamic profile in the work of
application of the blade.
[0019] In addition, all the cavities for housing the anchoring
elements of the attachment between the blade sections are located
at the inner portion of the structural walls of the sections,
whereby said walls of the sections are not very weakened, and the
outer surface thereof remains continuous, such that the efficiency
of the aerodynamic profile for the performance of the blade is not
affected.
DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 shows an exploded perspective view of the structural
assembly of a wind turbine blade according to the object of the
invention.
[0021] FIG. 2 is a perspective view of an enlarged detail of the
end corresponding to the blade root of the previous figure.
[0022] FIG. 3 is a frontal view of the previous blade root.
[0023] FIGS. 4, 5 and 6 show non-limiting examples of structural
embodiments of wind turbine blades, with which the invention can be
applied.
[0024] FIG. 7 is a perspective view of an example of a wind turbine
blade according to the invention, made in a single longitudinal
section.
[0025] FIG. 8 is a perspective view of an example of a wind turbine
blade according to the invention, made with two longitudinal
sections.
[0026] FIG. 9 is an exploded perspective view of the attachment of
the component sections of the previous figure.
[0027] FIG. 10 is a perspective view of the area of the attachment
of the component sections of the blade, with the outer skins being
transparent to observe the elements of the inside.
[0028] FIG. 11 is an enlarged sectioned detail of the arrangement
of an anchoring rod in the attachment between the component
sections of the blade.
DETAILED DESCRIPTION OF THE INVENTION
[0029] The object of the invention relates to a wind turbine blade,
in which features improving the constructive formation of the blade
and its functionality have been determined.
[0030] The proposed blade is of the type comprising two outer
lateral skins (1), arranged on an inner structure formed by
stringers (2) in the manner of longitudinal partitions, such that
the outer lateral skins (1) determine the aerodynamic profile of
the blade, together with a complementary part (3) defining the
leading edge, whereas in the opposite portion the mentioned outer
lateral skins (1) are attached to one another determining the
trailing edge.
[0031] According to the invention, both the outer lateral skins (1)
and the stringers (2) of the inner structure determine, at the end
corresponding to the base of the blade, extensions (4) by means of
which there is formed a cylindrical section (5) forming the blade
root for the securing in the assembly on the rotating rotor of the
wind turbine of application.
[0032] The blade root is thus formed by the constructive assembly
itself of the blade, by means of the outer lateral skins (1) and
the stringers (2) of the inner structure which make up the
structural formation of the blade body, without need to
subsequently couple accessory parts for forming the root.
[0033] The attachment between the extensions (4) forming the
cylindrical section (5) which forms the root is determined by the
bonding of the corresponding edges, it being provided for such
purpose that the edges (6) of said extensions (4) are defined in a
bevel or in a stepped cut so that the bonding surface is greater
and the attachment is therefore stronger.
[0034] Said formation of the blade is applicable regardless of the
structural shapes of the outer lateral skins (1) and of the
stringers (2) of the inner structure, which can have various
configurations as observed in FIGS. 4, 5 and 6, in which
embodiments which are not limiting have been depicted only as
examples; whereas longitudinally the blade can be in a single
section such as the example of FIG. 7, or be formed with two or
more longitudinal sections (7, 8) such as the example of FIG. 8,
for the component sections (7, 8) to be attached in the
constructive assembly of the wind turbine in which the blade is
applied.
[0035] For the attachment of the sections (7, 8) of longitudinal
composition of the blade, an intermediate ring (9) is incorporated
in the coupling of the attachment as observed in FIGS. 6 to 8, said
intermediate ring (9) determining, on its front faces, channels
(9.1) in which the outer lateral skins (1) and the stringers (2) of
the inner structure of the sections (7, 8) which are attached are
fitted with their end edge, thus preventing the defibration of the
outer lateral skins (1) from the edge of the attachment, due to the
action of the wind during the function of the work of application
of the blade.
[0036] In the end portion corresponding to the attachment, the
outer lateral skins (1) of the sections (7, 8) are formed in the
area comprised between the stringers (2) of the inside, with an
inwardly thickened portion (10), there being defined in said
thickened portion, as well as in the stringers (2), longitudinal
holes (11) which are opposite one another in the sections (7, 8)
which are attached, as well as in relation to corresponding through
holes which the intermediate ring (9) has between its front
channels (9.1).
[0037] The longitudinal holes (11) of the sections (7, 8) open out
into respective cavities (12 and 13) made perpendicularly over the
inner portion of the walls of said sections (7, 8), such that in
one of the sections, for example the section (7), the cavities (12)
into which the respective longitudinal holes (11) open out are
cylindrical, cylindrical elements (14) being fitted therein, which
cylindrical elements are provided with a threaded transverse hole
(14.1) for the threaded coupling of the end of a rod (15) which is
inserted through the respective longitudinal hole (11).
[0038] In the other section of the blade, in this case the section
(8), the cavities (13) into which the respective longitudinal holes
(11) open out are oblong, there being housed in each of these
cavities (13) a stop washer (16) and a nut (17) which is
incorporated on the other end of the rod (15) passing through the
respective longitudinal hole (11), such that said nut (17) can be
actuated through the opening of the oblong cavity (13) to establish
therewith tightening for tensioning the rod (15).
[0039] In such conditions, to establish the anchoring of attachment
between the sections (7, 8), the cylindrical elements (14) are
first inserted in the cavities (12) of the section (7) and
respective rods (15) are introduced through the corresponding
longitudinal holes (11), which rods are coupled by screwing on the
mentioned cylindrical elements (14), whereby said rods (15) are
fixed with respect to the section (7), projecting at the front
thereof through the longitudinal holes (11).
[0040] Once this is done, the intermediate ring (9) is placed,
making the rods (15) passing through the holes thereof until said
intermediate ring (9) abuts against the section (7), and in this
arrangement, in order to establish the attachment of the section
(8), the insertion of both sections (7, 8) in relation to one
another is carried out, making the rods (15) be introduced in the
longitudinal holes (11) of the section (8), up to the oblong
cavities (13) thereof, wherein the washers (16) and the
corresponding nuts (17) are incorporated on the end of the rods
(15), such that by tightening the nuts (17) a tension of the rods
(15) is obtained which assures the attachment between the sections
(7, 8), as observed in FIG. 11.
[0041] The cavities (12 and 13) do not pass to the outside of the
outer lateral skins (1) of the sections (7, 8), such that the
aerodynamic profile of the blade is not affected by the anchoring
of the attachment; the actuation on the nuts (17) being able to be
performed from the inside of the blade in order to perform the
assembly for the formation thereof.
* * * * *