U.S. patent application number 13/583066 was filed with the patent office on 2013-01-03 for wall portion for a tower of a wind turbine.
Invention is credited to Steen Kirkegaard Jensen, Anders Nygaard Rasmussen.
Application Number | 20130000241 13/583066 |
Document ID | / |
Family ID | 43446745 |
Filed Date | 2013-01-03 |
United States Patent
Application |
20130000241 |
Kind Code |
A1 |
Jensen; Steen Kirkegaard ;
et al. |
January 3, 2013 |
WALL PORTION FOR A TOWER OF A WIND TURBINE
Abstract
A wall portion for a tower of a wind turbine is provided. The
wall portion has a first wall segment having a first flange at a
lateral side of the first wall segment; a connection plate having a
surface portion being mounted at a front side surface portion of
the first wall segment; a second wall segment having a second
flange at a lateral side of the second wall segment; and a third
wall segment. The second flange is mechanically connected to the
first flange. The connection plate protrudes an edge at another
lateral side of the first wall segment. Another surface portion of
the connection plate is mounted at a front side surface portion of
the third wall segment and the connection plate protrudes an edge
at a lateral side of the third wall segment.
Inventors: |
Jensen; Steen Kirkegaard;
(Skanderborg, DK) ; Rasmussen; Anders Nygaard;
(Kobenhavn, DK) |
Family ID: |
43446745 |
Appl. No.: |
13/583066 |
Filed: |
June 9, 2010 |
PCT Filed: |
June 9, 2010 |
PCT NO: |
PCT/EP2010/058052 |
371 Date: |
September 6, 2012 |
Current U.S.
Class: |
52/651.01 ;
52/655.1 |
Current CPC
Class: |
F05B 2240/912 20130101;
F03D 80/00 20160501; F05B 2240/40 20130101; F03D 13/10 20160501;
Y02E 10/728 20130101; E04H 12/085 20130101; F03D 13/20
20160501 |
Class at
Publication: |
52/651.01 ;
52/655.1 |
International
Class: |
E04B 1/38 20060101
E04B001/38; E04H 12/00 20060101 E04H012/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 12, 2010 |
EP |
10156336.9 |
Claims
1.-15. (canceled)
16. A wall portion for a tower of a wind turbine, comprising: a
first wall segment comprising a first flange at a first lateral
side of the first wall segment; a connection plate comprising a
first surface portion being mounted at a front side surface portion
of the first wall segment, the connection plate protruding an edge
at a second lateral side of the first wall segment; a second wall
segment comprising a second flange at a first lateral side of the
second wall segment, wherein the second flange is mechanically
connected to the first flange; and a third wall segment, wherein a
second surface portion of the connection plate is mounted at a
front side surface portion of the third wall segment, the
connection plate protruding an edge at a lateral side of the third
wall segment, wherein the first flange and the second flange extend
in a longitudinal direction of the tower of the wind turbine.
17. The wall portion according to claim 16, wherein the first wall
segment and the second wall segment are laterally spaced apart from
each other in a first direction.
18. The wall portion according to claim 16, wherein the first wall
segment and the third wall segment are laterally spaced apart from
each other in a second direction different from the first
direction.
19. The wall portion according to claim 16, wherein the edge of the
first wall segment is adjacent to the edge of the third wall
segment.
20. The wall portion according to claim 16, wherein the first
surface portion of the connection plate and the second surface
portion of the connection plate are arranged on a same side of the
connection plate.
21. The wall portion according to claim 16, wherein the first
surface portion of the connection plate is in contact with the
front side surface portion of the first wall segment.
22. The wall portion according to claim 16, wherein a friction
increasing material is arranged between the first surface portion
of the connection plate and the front side surface portion of the
first wall segment.
23. The wall portion according to claim 16, wherein a thickness of
the connection plate is greater than a thickness of at least one of
the first wall segment and the third wall segment.
24. The wall portion according to claim 16, further comprising: a
further connection plate comprising a first surface portion being
mounted at a back side surface portion of the first wall segment,
wherein the back side surface portion of the first wall segment is
opposite to the front side portion of the first wall segment,
wherein a second surface portion of the further connection plate is
mounted at a back side surface portion of the third wall segment,
and wherein the back side surface portion of the third wall segment
is opposite to the front side portion of the third wall
segment.
25. The wall portion according to claim 24, wherein a thickness of
at least one of the connection plate and the further connection
plate equals to at least half of a thickness of at least one of the
first wall segment and the third wall segment.
26. The wall portion according to claim 24, wherein the connection
plate and/or the further connection plate is mounted using a bolt
and/or a nut.
27. The wall portion according to claim 16, wherein the first wall
segment, the second wall segment and/or the third wall segment
comprises steel.
28. The wall portion according to claim 16, wherein the first
flange of the first wall segment is integrally formed with the
first wall segment.
29. The wall portion according to claim 28, wherein the first
flange of the first wall segment is integrally formed with the
first wall segment by bending.
30. The wall portion according to claim 16, wherein the first
flange of the first wall segment is a component separate from the
first wall segment and connected to the first wall segment.
31. A wind turbine tower wall, comprising: a wind turbine tower
wall portion according to claim 16, wherein the first flange of the
first wall segment protrudes into an inside of a tower of the wind
turbine tower wall.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the US National Stage of International
Application No. PCT/EP2010/058052 filed Jun. 9, 2010 and claims the
benefit thereof. The International Application claims the benefits
of European application No. 10156336.9 filed Mar. 12, 2010, both of
the applications are incorporated by reference herein in their
entirety.
FIELD OF INVENTION
[0002] The present invention relates to a wall portion for a tower
of a wind turbine and to a wind turbine tower wall comprising the
wall portion. In particular, the present invention relates to a
wall portion for a tower of a wind turbine comprising three wall
segments being connected by flanges and being connected using a
connection plate.
BACKGROUND OF THE INVENTION
[0003] US 2008/0256892 A1 discloses a wind energy plant tower,
wherein a tower wall consists of a plurality of wall sections which
comprise connection bores to connect to adjacent border sections in
the longitudinal direction.
[0004] WO 2009/097858 discloses a tower element for a tower for a
wind power plant, wherein the tower element is provided with
inwardly facing flanges at the longitudinal sides, the flanges
being connected to corresponding flanges on laterally arranged
segments.
[0005] EP 2 136 017 A1 discloses an upper tower ring and a lower
tower ring arranged such that a bottom section of the upper ring
overlaps the top section of the lower ring in a horizontal overlap
region.
[0006] WO 2004/083633 discloses a tower section for a wind turbine,
wherein vertical flanges are tightened together by bolts and
wherein upper and lower horizontal flanges are provided to allow
interconnection of tower sections one on top of each other.
[0007] EP 2 006 471 B1 discloses a wind turbine tower having a
polygonal cross-section, wherein the wind turbine tower comprises a
number of segments which are connected with each other using a
splice plate.
[0008] There may be a need for a wall portion for a tower of a wind
turbine which allows assembly of a large tower of a wind turbine,
wherein the tower of the wind turbine has increased size (diameter,
height) compared to a conventional wind turbine tower and also has
sufficient stability and stiffness in rough environments. Further,
there may be a need for a wall portion for a tower of a wind
turbine which can easily be assembled and which has a sufficient
stability to be used in a tower of a wind turbine. Further, there
may be a need for a wind turbine tower wall for assembling a wind
turbine, wherein the wind turbine tower wall has increased size
(diameter, height) compared to a conventional wind turbine tower
and which provide an optimized construction.
SUMMARY OF THE INVENTION
[0009] This need may be met by the subject matter according to the
independent claims. Advantageous embodiments of the present
invention are described by the dependent claims.
[0010] According to an embodiment the wall portion for a tower of a
wind turbine comprises a first wall segment having a first flange
at a lateral side of the first wall segment; a connection plate
having a surface portion being mounted at a front side surface
portion of the first wall segment, the connection plate protruding
an edge at another lateral side of the first wall segment; a second
wall segment having a second flange at a lateral side of the second
wall segment, wherein the second flange is mechanically connected
to the first flange; and a third wall segment, wherein another
surface portion of the connection plate is mounted at a front side
surface portion of the third wall segment, the connection plate
protruding an edge at a lateral side of the third wall segment,
wherein the first flange and the second flange extend in a
longitudinal direction of the tower of the wind turbine.
[0011] The first wall segment, the second wall segment, and the
third wall segment may each comprise a plate-like structure
extending primarily in two different lateral directions and further
extending in a thickness direction perpendicular to the two lateral
directions. Thereby, an extent of the first wall segment, the
second wall segment and/or the third wall segment in the lateral
directions may be much larger (such as 10 times, 100 times, 1000
times) than the extent of the first wall segment, the second wall
segment, and/or the third wall segment in the thickness direction.
For example, an extent in the thickness direction of the three wall
segments may range between 20 mm to 100 mm, in particular between
30 mm and 70 mm. For example, an extent of the first wall segment,
the second wall segment, and/or the third wall segment in at least
one of the lateral directions may amount to between 1 m to 5 m, in
particular between 2 m and 4 m.
[0012] In particular the first, the second and the third wall
segments may comprise a metal, such as steel, iron and/or copper.
In particular, the first wall segment, the second wall segment
and/or the third wall segment may be planar plates, may be segments
of a cylinder, may be segments of a cone, or may be a combination
of the aforementioned geometrical shapes. In particular, the first
wall segment, the second wall segment and the third wall segment
may be substantially of a same shape.
[0013] The first wall segment, the second wall segment and the
third wall segment (also referred to as the three wall segments)
may each comprise at least one flange. Thereby, the flange may
comprise a protruding rim at a lateral side of the corresponding
wall segment, wherein the rim protrudes perpendicular to the
lateral directions (i.e. in the thickness direction). A front side
surface portion (or a backside surface portion) of one of the three
wall segments may include an angle with a flange connection surface
(for connecting adjacent flanges of two different of the three wall
segments), wherein this angle may amount to between 70.degree. and
120.degree., in particular between 80.degree. and 100.degree., in
particular around 90.degree.. Further, the first flange may
comprise at least one bore (or a hole) for inserting a bolt or a
screw which may also reach through a bore or a hole in the second
flange for connecting the first flange to the second flange (in
particular also by using a nut).
[0014] The first flange and the second flange extend in a
longitudinal direction of the tower of the wind turbine. In
particular, when the wall portion is used to assemble a wind
turbine tower wall the first flange may extend in a vertical
direction (or z-direction) along a vertical edge of the first wall
segment, as the longitudinal direction of the tower may be the
vertical direction. Thereby, adjacent wall segments of the wind
turbine tower wall (being arranged side by side) may be
advantageously connected using flange connection surfaces opposing
each other (for example by pressing the flange connection surfaces
together using at least one bolt). In particular, when assembled
into a wind turbine tower wall the first flange and the second
flange may protrude to an inside of the tower. Thereby, a smooth
outside surface of the wind turbine tower wall may be provided.
Further, a stability of the vertical connections of adjacent wall
segments may be increased. Further, by providing the first flange
at the first wall segment and the second flange at the second wall
segment welding of adjacent wall segments may be avoided, thus
simplifying an assembly of a wind turbine tower wall from
individual wall segments.
[0015] Further the connection plate may provide horizontal
connections of the first wall segment and the third wall segment,
when the wall portion is used to assemble a wind turbine tower
wall.
[0016] In particular, a wind turbine wall may be assembled from
plural (such as 10, 20, 30, 40 or even more) wall segments.
Thereby, the size of the individual wall segments may be small
enough to be easily transported on a truck or on a train.
Nevertheless, the assembled wind turbine tower wall may have a
larger size than conventional wind turbine tower walls. In
particular, the wind turbine tower wall may have a diameter of more
than 4 m, in particular more than 6 m, in particular more than 10
m, and may have a height larger than 60 m, in particular larger
than 100 m, further in particular larger than 150 m.
[0017] At the top of the wind turbine tower a nacelle may be
mounted comprising a hub at which one or more rotor blades are
fixed. Further, the nacelle may comprise a rotor driving a
generator, wherein the rotor is connected to the hub such that
rotating the rotor by the connected rotor blades causes generating
electric energy output by the electric generator. Since at higher
elevations a wind velocity may be higher than in lower elevations
the wind turbine may produce more electric energy or power than a
conventional wind turbine.
[0018] The connection plate may comprise a metal, such as steel,
iron, and/or copper. The connection plate may have an extent in two
different lateral directions which is much larger than in a
thickness direction perpendicular to the two lateral directions
(for example 10 times, 100 times, 200 times larger). The connection
plate may be a component separate from each of the three wall
segments and may be fixed to the first wall segment and/or to the
third wall segment using at least one bolt and/or nut.
[0019] Thereby, the surface portion of the connection plate may
come into direct or indirect contact with the front side surface
portion of the first wall segment. Further, the other surface
portion of the connection plate may come in direct or indirect
contact with the front side surface portion of the third wall
segment. Direct contact thereby means that no (macroscopic)
structure is placed between the two surface portions being in
contact with each other. Thereby, it may not be excluded that
contaminating elements, compounds or layer(s) are arranged between
the two surface portions being in direct contact with each other.
Indirect contact between the two surface portions thereby means
that a macroscopic structure is placed between the two surface
portions. The mechanical connection strength of the connection
between the surface portion of the connection plate and the front
side surface portion of the first wall segment may result from
friction between the surface portion of the connection plate and
the front side surface portion of the first wall segment. The
friction may be increased by pressing the surface portions
together, for example by using one or more bolts arranged into one
or more holes provided in the connection plate and the first wall
segment and tightening them.
[0020] By allowing a direct or indirect contact between the surface
portions and by pressing the surface portions together by an
adjustable pressure the friction between the contacting surface
portions may be appropriately adjusted such as to generate an
appropriate connection strength between the connection plate and
the first wall segment. Similar considerations also hold for the
connection strength between the connection plate and the third wall
segment.
[0021] Assembled into a wind turbine tower wall the connection
plate may provide a connection between the first wall segment and
the third wall segment arranged on top of each other. Thereby, the
connection plate may provide a connection between the wall segments
along a horizontal line.
[0022] In particular, a portion of the connection plate protruding
the edge at the other lateral side of the first wall segment is
mounted at the third wall segment and a portion of the connection
plate protruding the edge at the lateral side of the third wall
segment is mounted at the first wall segment.
[0023] In particular the three wall segments may comprise steel
plates for assembling a wind turbine tower, wherein the steel
plates are connected by an advantageous combination of bolt
tightened inwardly facing flanges on vertical connections and by
means of splice plates (connection plates) on horizontal
connections between the steel plates.
[0024] In particular, the connection plate may have an extent at
least 50%, in particular 75%, in particular 90% of an extent of the
edge at the other lateral side of the first wall segment. In
particular, the extent of the connection plate may be substantially
the same as an extent of the edge at the other lateral side of the
first wall segment.
[0025] In particular, an extent of the first flange may be at least
50%, in particular 75%, in particular 90% of an extent of the first
wall segment at the lateral side. In particular, an extent of the
first flange may be substantially equal to an extent of the first
wall segment at the lateral side.
[0026] According to an embodiment the first wall segment and the
second wall segment are laterally spaced apart from each other in a
first direction. In particular, the first direction may be a
horizontal direction, when the wall portion is assembled into a
wind turbine tower wall. In particular, the first wall segment and
the second wall segment may be arranged side by side such that a
flange connection surface of the first flange is in direct or
indirect contact with a flange connection surface of the second
flange. Thus, the first wall segment and the second wall segment
may be in direct or indirect contact with each other via the first
flange and the second flange. Thereby, an annular wind turbine
tower wall section may be assembled by plural wall segments
connected side by side by corresponding flange pairs.
[0027] According to an embodiment the first wall segment and the
third wall segment are laterally spaced apart from each other in a
second direction different from the first direction. In particular,
the second direction may be a vertical direction when the wall
portion is used to build up a wind turbine tower wall. Thereby, a
height of the wind turbine tower wall may be increased by placing
plural wall segments on top of each other, wherein adjacent wall
segments may be connected by plural connection plates connecting
adjacent wall segments being spaced apart in the vertical
direction. Thereby, the connection plate(s) may provide connection
between adjacent wall segments along a horizontal line. Thereby,
plural annular wind turbine tower wall sections (each comprised of
plural wall segments connected side by side by corresponding flange
pairs) may be connected on top of each other using one or more
connection plates. Thereby, a great degree of flexibility with
respect to a size, geometry and other construction properties in
the construction of a wind turbine tower wall may be provided.
[0028] According to an embodiment the edge of the first wall
segment is adjacent to the edge of the third wall segment. In
particular, the edge of the first wall segment may be in contact
with the edge of the third wall segment. Thereby, the wall portion
may be a tight wall portion.
[0029] According to an embodiment the surface portion of the
connection plate and the other surface portion of the connection
plate are arranged on a same side of the connection plate. Thereby,
the front side surface portion of the first wall segment and the
front side surface portion of the third wall segment may be flush
with each other. Thereby, a smooth wall portion may be provided.
Further, a stability and/or stiffness of the wall portion (in
particular when used in a wind turbine tower wall) may be improved,
as a load force line may run through the first wall segment as well
as through the third wall segment in a vertical direction.
[0030] According to an embodiment the surface portion of the
connection plate is in contact with the front side surface portion
of the first wall segment. In particular, the surface portion of
the connection plate may be in direct contact (in particular having
no macroscopic structure placed in between) with the front side
surface portion of the first wall segment. Nevertheless, some
contamination, such as an oxide layer, contaminating elements or
compounds, or a dust or soil layer may be present between the
surface portion of the connection plate and the front side surface
portion of the first wall segment. Direct contact between the
surface portion of the connection plate and the front side surface
portion of the first wall segment may increase a friction between
these surface portions to thereby increase the connection strength
between the connection plate and the first wall segment. A
connection between the connection plate and the tower wall portion
may be provided in a similar way.
[0031] According to an embodiment a friction increasing material is
arranged between the surface portion of the connection plate and
the front side surface portion of the first wall segment. Thereby,
a friction between the surface portion of the connection plate and
the front side surface portion of the first wall segment having no
friction increasing material arranged in between may be less than
the friction between the surface portion of the connection plate
and the front side surface portion of the first wall segment having
the friction increasing material arranged in between. Thereby, the
pressure pressing the surface portion of the connection plate and
the front side surface portion of the first wall segment should be
the same for determining whether the friction is increased or not.
Further the surface portions of the connection and/or the (first)
wall segment may be pre-treated by spray-metalishing, mechanical
abrasion, abrasive blasting, chemical treatment, electro chemical
treatment and/or treatment with barrier creating paint.
[0032] According to an embodiment a thickness of the connection
plate is greater than a thickness of at least one of the first wall
segment and the third wall segment. Thereby, a connection strength
between the first wall segment and the third wall segment due to
the connection plate may be improved. In particular, the thickness
of the connection plate may be greater than a thickness of at least
one of the first wall segment and the third wall segment, if only
one connection plate is utilized for connecting the first wall
segment and the third wall segment.
[0033] According to an embodiment the wall portion further
comprises a further connection plate a surface portion of which
being mounted at a back side surface portion of the first wall
segment, wherein the back side surface portion of the first wall
segment is opposite to the front side portion of the first wall
segment, wherein another surface portion of the further connection
plate is mounted at a back side surface portion of the third wall
segment, and wherein the back side surface portion of the third
wall segment is opposite to the front side portion of the third
wall segment.
[0034] The further connection plate may in particular be arranged
opposite to the connection plate and may in particular be of a
similar shape and/or structure as the connection plate. By
providing the connection plate and the further connection plate a
connection strength may be improved and enhanced, as the further
connection plate provides additional friction. In particular, the
backside surface portion of the first wall segment and the backside
surface portion of the third wall segment may be flush with each
other. In particular, the connection plate and/or the further
connection plate may have a shape that is planar, curved,
cylindrical, and/or conical.
[0035] According to an embodiment a thickness of at least one of
the connection plate and the further connection plate amounts to at
least half of a thickness of at least one of the first wall segment
and the third wall segment. Thereby, by providing two connection
plates each of them may be provided thinner than in the case of
only one connection plate connecting the first wall segment to the
third wall segment.
[0036] According to an embodiment the connection plate and/or the
further connection plate is mounted using a bolt and/or a nut.
Thereby, welding the connection plate and/or the further connection
plate to the first wall segment and/or the third wall segment may
be avoided, thus simplifying the assembly and setup of the wind
turbine tower wall.
[0037] According to an embodiment at least one of the first wall
segment, the second wall segment and the third wall segment
comprises steel, in particular stainless steel. Thereby, a very
rigid and stable wall portion for a tower of a wind turbine may be
provided.
[0038] According to an embodiment the first flange of the first
wall segment is integrally formed with the first wall segment, in
particular by bending. According to another embodiment the first
flange of the first wall segment is integrally formed with the
first wall segment by casting. Thereby, the first flange may be
manufactured in a simple way. According to an embodiment the first
wall segment (or any of the three wall segments) may be
manufactured by rolling a metal, in particular by rolling steel.
Further, after-treatment by bending a portion of the first wall
segment may be employed for forming the first flange.
[0039] According to an embodiment the first flange of the first
wall segment is a component separate from the first wall segment
and is connected to the first wall segment. Thereby, the
manufacturing the first wall segment may be simplified as the first
wall segment may be prepared or manufactured by rolling steel and
connecting the separate first flange after having rolled the steel.
The connection may be provided by a bolt and/or a nut, for example.
Alternatively, the first flange may be welded to a metal structure
to complete the first wall segment.
[0040] According to an embodiment a wind turbine tower wall is
provided which comprises a wind turbine tower wall portion
according to an embodiment as described above, wherein the first
flange of the first wall segment protrudes into an inside of a
tower defined by the wind turbine tower wall. Thereby, a smooth
outer surface of the wind turbine tower wall may be provided
improving an aesthetic appearance of the wind turbine tower
wall.
[0041] It has to be noted that embodiments of the invention have
been described with reference to different subject matters. In
particular, some embodiments have been described with reference to
method type claims whereas other embodiments have been described
with reference to apparatus type claims. However, a person skilled
in the art will gather from the above and the following description
that, unless other notified, in addition to any combination of
features belonging to one type of subject matter also any
combination between features relating to different subject matters,
in particular between features of the method type claims and
features of the apparatus type claims is considered as to be
disclosed with this document.
[0042] The aspects defined above and further aspects of the present
invention are apparent from the examples of embodiment to be
described hereinafter and are explained with reference to the
examples of embodiment. The invention will be described in more
detail hereinafter with reference to examples of embodiment but to
which the invention is not limited.
[0043] Thereby, elements, components and/or method steps similar in
structure and/or function are denoted by reference signs differing
only in the first position. As far as an element, a component, or a
method step is not described in detail with respect to a particular
embodiment the description of the corresponding element, component,
or method step with respect to another embodiment may serve as an
auxiliary description for this element, component, or method step
in the particular embodiment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] FIG. 1 schematically illustrates a wall portion for a tower
of a wind turbine according to an embodiment;
[0045] FIG. 2 schematically illustrates a cross-sectional view of
two wall segments of the wall portion illustrated in FIG. 1 and
illustrates the connection between the two wall segments;
[0046] FIG. 3 schematically illustrates a cross-sectional view of
two wall segments comprised in the wall portion illustrated in FIG.
1 and illustrates the connection between the two wall segments.
DETAILED DESCRIPTION OF THE INVENTION
[0047] The illustration in the drawing is schematically. It is
noted that in different figures, similar or identical elements are
provided with the same reference signs or with reference signs,
which are different from the corresponding reference signs only
within the first digit.
[0048] FIG. 1 schematically illustrates a side view of a wall
portion 100 for a tower 101 of a wind turbine. In the illustrated
embodiment the wind turbine tower wall 101 has a slightly conical
shape such that a diameter of the wind turbine tower wall 101
decreases for an increasing height along the vertical direction z
of the tower. In other embodiments the wind turbine tower wall may
have a cylindrical shape, a polygonal shape or any other shape.
[0049] The wind turbine tower wall 101 is assembled from plural
wall segments from which only the wall segments 103, 105 and 107
are shown. The wall segments 103, 105 and 107 are connected to each
other to form the wall portion 100 for a tower of a wind turbine.
The wall segment 103 has a flange 109 formed integrally with the
wall segment 103. The flange 109 protrudes inwardly into an inside
of the wind turbine tower which is defined by the wind turbine
tower wall 101. The wall segment 107 also comprises a flange 111
protruding into an inside of the wind turbine tower and being
opposite to the flange 109 of the wall segment 103. The flanges 109
and 111 are connected to each other by bolts 113. The flange 109 is
arranged at a lateral side of the wall segment 103 such that the
flange 109 extends primarily in the vertical z-direction.
[0050] The wall segment 105 arranged above the wall segment 103 is
connected to the wall segment 103 using a splice plate (connection
plate) 115, wherein an upper portion of the slice plate 115 is
connected to the upper wall segment 105 using bolts 117 and a lower
portion of the splice plate 115 is connected to the lower wall
segment 103 by bolts 119.
[0051] The wind turbine tower wall 101 thus comprises steel plates
103, 105 and 107 which are united at vertical (along the z-axis)
connections 121 by inwardly facing flanges 109, 111 and at
horizontal (along the x-axis and/or y-axis) connections 123 by
means of slice plate 115 which is connected to the steel plates
103, 105 by bolts 117, 119.
[0052] FIG. 2 schematically illustrates a cross-sectional view
(along line 11A in FIG. 1) of the horizontal connection by means of
the splice plate 115 arranged at an outside surface of the wind
turbine tower wall 101 and a splice plate 116 arranged in an inside
of the wind turbine tower wall 101. The wall segment 105 is
arranged in the vertical direction z above the wall segment 103
such that the wall segment 105 and the wall segment 103 are in an
"end-to-end" configuration such that an lower edge 124 of the wall
segment 105 is adjacent to an upper edge 125 of the wall segment
103.
[0053] Further, a back surface 127 of the wall segment 105 is flush
with a back surface 129 of the wall segment 103. Further, a portion
of the back surface 127 of the wall segment 105 is in contact with
a surface portion 131 of the splice plate 116. Thereby, pressure is
applied by tightening the bolt 117 such that a friction resistance
is generated between the surface portion 131 of the splice plate
116 and a portion of the back surface 127 of the wall segment
105.
[0054] Another surface portion 133 of the splice plate 116 is in
contact with a portion of the back surface 129 of the wall segment
103, wherein also a friction resistance between the splice plate
116 and the wall segment 103 is generated by tightening the bolt
119.
[0055] Thereby, the connection between the wall segment 105 and the
wall segment 103 may be achieved by having a second splice plate
115 arranged opposite to the splice plate 116 such that also
between a front surface 135 and the splice plate 115 as well as
between the front side surface 137 and the splice plate 115
friction is generated. When using two splice plates 115 and 116, a
thickness d2 of the splice plates 115, 116 may be greater than half
of a thickness d1 of each of the wall segments 105, 103.
[0056] In other embodiments only one splice plate is provided on
either the inner side or the outer side of the wind turbine tower
wall. When using only one splice plate a thickness d2 of the single
splice plate should be not less than a thickness d1 of the wall
segments 105, 103.
[0057] FIG. 3 schematically illustrates a cross-sectional view
(along line IIB in FIG. 1) of the vertical connection using flanges
109, 111, as illustrated in FIG. 1. In this cross-sectional view
the vertical z-axis is perpendicular to the drawing plane. In the
illustrated embodiment the wall segments 103 and 107 have a curved
shape in cross-section, in particular they have a shape of a
cylinder segment. In other embodiments the wall segments 103, 107
may have a planar shape, such as for assembling a polygonal wind
turbine tower wall.
[0058] The wall segments 103, 107 are arranged side by side such
that the flanges 109, 111 are opposite to each other, wherein a
flange connection surface 139 of the flange 111 is in direct
contact with a flange connection surface 141 of the flange 109. A
contact pressure between the flange connection surfaces 139, 141 is
adjusted by tightening a bolt 113 such that a friction resistance
is established between the flange connection surfaces 139 and 141.
Thereby, a vertical connection between the wall segments 103 and
107 is established.
[0059] The use of a segmented construction of a wind turbine tower
may overcome the dimensional restrictions during transportation.
The individual wall segments 103, 107 and 105 may easily be
transported using for example a truck or a train. By using splice
plates 115, 116 at horizontal connections between wall segments it
may be ensured that stresses, such as gravity forces, are
transferred between the united steel plates or wall segments in an
advantageous manner so that the dimensions of the steel
construction as a whole may be minimized.
[0060] Steel plates or wall segments bolted together by bolt 113,
117, 119 may eliminate the welding process and subsequent control
of welds as is required in conventional methods for manufacturing a
wind turbine tower wall. Further, the connections may have very
good fatigue properties and moreover the plates may be easily
assembled.
[0061] By using inwardly facing flanges 109, 111 for construction
on the vertical connections 121 of the wall segments 103 and 107 it
may be ensured that sufficient connections between the wall
segments or steel plates are made. The facing flanges 109, 111 for
the vertical connections may have the result that the overall
stiffness of the wall portion structure 100 or plate structure is
enhanced i.e. the buckling capacity on the tower may be increased.
This in turn may have the advantage that the dimensions of the wall
segments or steel plates may be decreased. Furthermore, the use of
flanges 109, 111 which are connected to each other inside the tower
avoids a tightening of bolts from the outside of the tower, thus
simplifying the construction and improving the aesthetic appearance
of the tower.
[0062] By combining the two types of connections for vertical and
horizontal connections, an advantageous tower construction may be
made. The construction may have also the advantage that the
dimensions of the steel plates (wall segments) may be decreased,
thereby decreasing the costs.
[0063] According to an embodiment only one splice plate on one side
of the horizontal connections is provided. In this case the
thickness of the single splice plate may be somewhat greater than
that of either of the wall segments or steel plates to be connected
or to be united, in order to allow for the extra stress caused by
the cover plate or splice plate being out of the direct line of
stress.
[0064] For one embodiment the splice plate may be connected to the
flat plates or wall segments by means of bolts and nuts. For
various embodiments the plates or wall segments to be united or
connected and/or the splice plates 115, 116 may be made of steel or
of a rust resistance steel in order to make surface treatment
redundant.
[0065] For various embodiments the plates to be united or to be
connected and/or the splice plates may be pre-treated with friction
creating material on the joining surfaces 131, 127, 129, 133. This
treatment may for various embodiments by spray metalishing and/or
treatment with barrier creating paint.
[0066] For various embodiments the flange connection may further
comprise flanges divided into several parts which are then bolted
together alternately. This means that flanges with a very large
cross-section may be avoided.
[0067] For various embodiments of the invention the said vertical
flanges may be separate flange constructions attached to the wall
segments or steel plate or the flanges may preferably be bended
parts of the wall segments or steel plates.
[0068] It should be noted that the term "comprising" does not
exclude other elements or steps and "a" or "an" does not exclude a
plurality. Also elements described in association with different
embodiments may be combined. It should also be noted that reference
signs in the claims should not be construed as limiting the scope
of the claims.
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