U.S. patent application number 14/682844 was filed with the patent office on 2015-07-30 for process and unit for the attachment of a wind turbine's tower to a foundation and wind turbine incorporating said unit.
The applicant listed for this patent is ACCIONA WINDPOWER, S.A.. Invention is credited to Teresa ARLAB N GABEIRAS, Eduardo AZANZA LADRON, Carlos CERD N MART NEZ, Javier CI URRIZ MART N, Javier FERN NDEZ DE MANZANOS, Jose Miguel GARC A SAYES, Ivan GARCiA MAESTRE, Koldo LARUMBE FERNANDINO, Miguel NUNEZ POLO.
Application Number | 20150211251 14/682844 |
Document ID | / |
Family ID | 48425453 |
Filed Date | 2015-07-30 |
United States Patent
Application |
20150211251 |
Kind Code |
A1 |
GARCiA MAESTRE; Ivan ; et
al. |
July 30, 2015 |
PROCESS AND UNIT FOR THE ATTACHMENT OF A WIND TURBINE'S TOWER TO A
FOUNDATION AND WIND TURBINE INCORPORATING SAID UNIT
Abstract
The invention describes a process and a unit, both enabling to
attach a wind turbine tower to a foundation, as well as describes
also a wind turbine incorporating the unit. The process features a
stage of installation of a support element for the transmission of
stresses from the tower to the foundation, followed by a stage of
leveling the support element and pouring foundation concrete up to
the support element's lower side so that the lower side is adhered
to the poured concrete once it has set. The unit comprises at least
one support element.
Inventors: |
GARCiA MAESTRE; Ivan;
(Navarra, ES) ; AZANZA LADRON; Eduardo; (Navarra,
ES) ; LARUMBE FERNANDINO; Koldo; (Navarra, ES)
; CERD N MART NEZ; Carlos; (Navarra, ES) ; ARLAB N
GABEIRAS; Teresa; (Navarra, ES) ; CI URRIZ MART N;
Javier; (Navarra, ES) ; FERN NDEZ DE MANZANOS;
Javier; (Navarra, ES) ; GARC A SAYES; Jose
Miguel; (Navarra, ES) ; NUNEZ POLO; Miguel;
(Navarra, ES) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ACCIONA WINDPOWER, S.A. |
Navarra |
|
ES |
|
|
Family ID: |
48425453 |
Appl. No.: |
14/682844 |
Filed: |
April 9, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13490151 |
Jun 6, 2012 |
9016005 |
|
|
14682844 |
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Current U.S.
Class: |
52/126.7 |
Current CPC
Class: |
E02D 27/42 20130101;
E04B 1/4157 20130101; E02D 27/425 20130101; Y02E 10/728 20130101;
Y02E 10/72 20130101; E04H 12/347 20130101; E04H 12/34 20130101 |
International
Class: |
E04H 12/34 20060101
E04H012/34; E02D 27/42 20060101 E02D027/42; E04B 1/41 20060101
E04B001/41 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 17, 2011 |
ES |
201131851 |
Claims
1. A unit for the attachment of a wind turbine tower to a
foundation, the foundation comprising concrete poured into a
foundation hole and a set of connection bolts between the tower and
the foundation embedded in the concrete, the unit comprising at
least one support element for the transmission of stresses from the
tower to the foundation placed in an assembled position so that its
upper side is in contact with the tower and its lower side is in
contact with and adhered to the concrete, the support element
comprising at least some orifices for the connection bolts to go
through.
2. The unit of claim 1, further comprising leveling and attachment
means for leveling and attaching the at least one support element
to the connection bolts.
3. The unit of claim 2, wherein the leveling and attachment means
comprise at least one threaded element which is located in
connection with the support element and is movable in relation to
the connection bolts, the connection bolts being also threaded so
that the elevation of the orifices of the support element is
variable through actuation of the threaded element.
4. The unit of claim 3, wherein the threaded element is located in
connection with the support element's lower side and is embedded in
the foundation concrete in an assembled position.
5. The unit of claim 4, wherein the threaded element is located in
contact with an intermediate element which is located also
connected to the support element, which is removable subsequently
to the leveling and attachment of the support element.
6. A wind turbine comprising: a tower, and a foundation
additionally comprising a unit for the attachment of the wind
turbine tower to the foundation comprising: at least one support
element for the transmission of stresses from the tower to the
foundation placed in an assembled position so that its upper side
is in contact with the tower and its lower side is in contact with
and adhered to the concrete, the support element comprising at
least some orifices for the connection bolts to go through.
7. The wind turbine of claim 6, further comprising leveling and
attachment means for leveling and attaching the at least one
support element to the connection bolts.
8. The wind turbine of claim 6, further comprising a lower section
comprising a flange with drills for the introduction of connection
bolts and for clamping said flange to the support element and the
foundation.
9. A unit for the attachment of a wind turbine tower to a
foundation, the foundation comprising concrete poured into a
foundation hole and a set of connection bolts between the tower and
the foundation embedded in the concrete, the unit comprising at
least one support element for the transmission of stresses from the
tower to the foundation placed in a position so that its lower side
is in contact with the foundation hole, the support element
comprising at least some orifices for the connection bolts to go
through.
10. The unit of claim 9, further comprising a leveling and
attachment device for leveling and attaching the at least one
support element to the connection bolts.
11. The unit of claim 10, wherein the leveling and attachment
device comprise at least one threaded element which is located in
connection with the support element and is movable in relation to
the connection bolts, the connection bolts being also threaded so
that the elevation of the orifices of the support element is
variable through actuation of the threaded element.
12. The unit of claim 11, wherein the threaded element is located
in connection with the support element's lower side.
13. A wind turbine comprising: a tower, and a foundation comprising
concrete poured into a foundation hole and a set of connection
bolts between the tower and the foundation embedded in the
concrete, wherein the wind turbine additionally comprises a unit
for the attachment of the wind turbine tower to the foundation
comprising: at least one support element for the transmission of
stresses from the tower to the foundation placed in a position so
that its lower side is in contact with the foundation hole, the
support element comprising at least some orifices for the
connection bolts to go through.
14. The wind turbine of claim 13, further comprising leveling and
attachment device for leveling and attaching the at least one
support element to the connection bolts.
15. The wind turbine of claim 13, further comprising a lower
section comprising a flange with drills for the introduction of
connection bolts and for clamping said flange to the support
element and the foundation.
Description
OBJECT OF THE INVENTION
[0001] The object of the invention is a process enabling the
attachment of a wind turbine tower to a foundation, as well as the
attachment unit enabling the aforementioned attachment between the
tower and the foundation, and the wind turbine itself which
incorporates said attachment unit.
BACKGROUND OF THE INVENTION
[0002] The objective of wind energy is to generate electricity from
the wind through wind turbines with the maximum possible efficiency
and the minimum cost. The most spread configurations of wind
turbines imply the use of one tower for the installation of the
rotor at some predetermined elevation relative to the ground.
[0003] These towers are designed to withstand the set of reactions
generated as a consequence of the loads to which both the wind
turbine's rotor and the nacelle are subjected. The ideal position
of the rotor to prevent the ground effect together with the blade
diameters cause the optimal height at which it should be placed to
increase as the wind turbine's electric power increases. In these
machines with large power it is common to use towers with a height
greater than 100 meters.
[0004] The attachment area, where the tower is attached to the
foundation is one of the critical design points of the wind turbine
and it has an impact in the latter's structural integrity.
[0005] The manufacturing of attachments between the tower's base
and the foundation is known in the state of the art, said
manufacturing essentially comprising the following steps:
[0006] First, a foundation hole is made in which a set of bolts,
over which the first the first section of the tower is to be
connected, are installed. Subsequently, concrete is poured in the
hole in a way that the bolts protrude thereof.
[0007] Later, a first section of the tower is added over the
already set concrete, wherein said concrete will be in contact with
leveling metal sheets placed between the aforementioned first
section and the foundation's concrete, said sheets intended for
correcting the manufacturing dimensional tolerances of the
foundation and correctly positioning the first section of the
tower.
[0008] Once the first section of the tower has been leveled over
the foundation, a cylindrical ring is installed on the perimeter
surrounding the section and grout is poured over the ring. The
grout collaborates in the attachment of the tower to the foundation
establishing an adhesive connection between the grout and the tower
on the upper section of the grout and between the grout and the
foundation on the lower section of the grout.
[0009] Finally, once the grout has set, torque is applied to the
bolts for tightening said bolts, the attachment being thereby
finished.
[0010] Other methods for the attachment of the tower to the
foundation are also known, in which a previous stage of making the
hole is also executed which is then filled with concrete and from
which the aforementioned bolts for connection to the tower's base
also protrude. Subsequently, a support element is located over the
foundation for the transmission of stresses from the tower to the
foundation which may be, for example, made of steel or concrete,
and which is placed over the concrete poured in the foundation hole
once said concrete has set.
[0011] Subsequently, the leveling of the support element is carried
out and then filling grout is poured in the space located between
the support element and the foundation concrete, for the connection
of the support element to the foundation. Once the filling grout
has set, the upper side of the support element is connected to the
tower's base through connection bolts which go through the
aforementioned support element. In this case, an adhesive
connection is established between the grout and the support element
on the grout's upper side and between the grout and the foundation
on the grout's lower side.
[0012] In both cases, the use of grout as an intermediate element
and the reaction stresses generated at the tower's base determine,
for a design of the predetermined tower section, the choice of the
type of foundation for a specific location, since the strength
mechanical capacity of the grout is limited and, at each location,
the stresses vary depending on the winds associated to each
aforementioned location. This creates the need to vary either the
dimensions of the hole or its strength capacity for each type of
tower.
[0013] Other disadvantages are the additional setting time that is
implied by the use of grout, which increases the tower's
construction time, as well as the influence of climatological
conditions on the grout's setting time and also on the quality of
the grout itself and, therefore, on the quality of the connection
or even on the impossibility to be able to pour the grout.
[0014] Finally, another disadvantage of the use of grout are the
associated quality problems, since the quality of the grout's seal
is critical and difficult to control and even to unify for each
wind turbine, since it depends, in addition to the climatological
conditions previously discussed, on the experience of the workers
or the existence of bubbles inside the grout which weaken the mix
and which may appear as a consequence of a variation of the
direction and speed of the grout in each area throughout the
surface with regards to previous calculations, these parameters
being difficult to control as they are affected by numerous
variables.
[0015] In the first attachment method of a tower to the foundation
known in the state of the art and described above, there is an
additional given disadvantage: since the stage of leveling is
applied to the tower's first section, it is necessary to use a high
tonnage crane to move the first section during the leveling stage,
thereby incurring in additional installation costs and the
possibility of a damage to the components.
DESCRIPTION OF THE INVENTION
[0016] The process for attachment of a wind turbine's tower to a
foundation object of the invention comprises the aforementioned
stages of: [0017] performing a foundation hole for the subsequent
pouring of foundation concrete inside, and [0018] placement in said
foundation hole of a set of connection bolts for connecting the
foundation to the tower.
[0019] However, the process is characterized by a sequence of
stages in which the installation of a support element having
capacities for stress transmission from the tower to the foundation
is carried out first, followed by a stage of leveling the element,
and when the aforementioned support element has been leveled, then
the foundation concrete is poured into the hole.
[0020] The invention is applied in an equivalent manner both to
onshore wind turbines, i.e., located on land, for which a hole is
made on the ground for pouring the concrete, as well for offshore
wind turbines, i.e. located at sea, for which formwork is performed
on land defining the aforementioned hole in which the concrete is
poured, this formwork being removed once the concrete has set, and
the set concrete being transported to its final location at sea
without the formwork.
[0021] More precisely, the process object of the invention is
characterized in that it comprises the following stages: [0022]
installation of at least one support element for the transmission
of stresses from the tower to the foundation, through the
introduction of connection bolts through at least some orifices of
the support element, [0023] leveling of the support element in the
foundation's hole, [0024] attachment of the leveled support element
to the connection bolts, [0025] subsequent to the attachment of the
support element, pouring of the foundation concrete into the
foundation hole to at least the lower side of the support element
in such a way that the lower side is adhered to the poured concrete
once it has set; [0026] subsequent to the setting of the concrete,
installation of at least one lower section of the tower over the
leveled support element, and [0027] attachment of the tower's lower
section to the connection bolts between the foundation and the
tower.
[0028] In the event that the wind turbine is offshore, the
installation of the support element, its leveling and attachment
and the subsequent pouring of the concrete into the foundation hole
or formwork would be carried out on land. Subsequently to the
concrete setting, the assembly made up of the concrete, the bolts
and the leveling element would be transported to its final location
at sea, which would therefore entail an additional stage of
transport of the aforementioned elements to the final location, and
this final location would be where the installation and attachment
of the tower's lower section would be carried out, as well as the
installation of the set over an offshore platform.
[0029] The process object of the invention has an initial advantage
of eliminating the need to use grout as the final filling element
in the attachment between the lower tower section and the
foundation, thereby solving the previously exposed technical
problems. This occurs because the support element allows, firstly,
performing the leveling over this element instead of over the
tower's lower section, and secondly, since there is a direct
attachment between the foundation concrete after its leveling, the
support element is integrated into the foundation itself,
establishing a connection through direct adhesion between the lower
side of the support element and the foundation concrete, without
the need for additional adhesives such as grout as in the
aforementioned case of the state of the art, since this support
element is pre-installed and leveled during the creation of the
foundation, and it is not until a subsequent stage that the
concrete is poured and, once set, the first section of the tower is
installed directly over the upper surface, already leveled, of the
support element. Two problems associated to the use of grout are
therefore eliminated.
[0030] Another additional advantage presented by the invention is
that it allows for the normalization and homogenization of the
foundations for different structural loads to be borne, since the
support element itself, which has the capacity to transmit stresses
from the tower to the foundation, is the variable and modifiable
part in the design of the attachment from the tower to the
foundation, as the larger the dimensions of the element are, the
greater is the allocation of stresses and therefore there is a
decrease of the tensions observed in this attachment area. This
entails an important reduction in the cost of manufacturing of the
foundations.
[0031] In addition to the aforementioned, there are other
advantages such as the improvement of the attachment quality, by
avoiding the problems derived from the lack of quality as
previously described due to the use of grout, since this is a
critical element in the attachment, but whose final result depends
on several variables, many of them impossible to control. Through
the leveling of the support element which conforms the attachment
unit and the process object of the invention the dimensional errors
in the use of concrete, present at least as foundation material in
any building solution of the wind turbine, are avoided and
additionally, by establishing a connection through adhesion between
the lower side of the support element and the foundation concrete,
the previously described quality problems arising from the use of
grout are eliminated.
[0032] Optionally, the stage of installing at least one support
element in the connection bolts may be done before or after the
stage of placing the connection bolts in the foundation hole. That
is to say, the support element(s) may come previously installed in
the set of bolts from the manufacturer or they may be installed in
the tower's location, or in the land area where the foundation work
is carried out in the case of offshore wind turbines, once the
above set of bolts has been positioned in the foundation hole.
[0033] A unit for attachment of a wind turbine tower to a
foundation is also an object of this invention, the foundation
comprising concrete poured into a foundation hole and a set of
connection bolts between the tower and the foundation embedded
inside the concrete.
[0034] According to what was previously described, the unit is
characterized in that it comprises: [0035] at least one support
element for the transmission of stresses from the tower to the
foundation, said support element placed in an assembled position so
that its upper side is in contact with the tower and its lower side
is in contact with and adhered to the concrete poured into the
foundation hole, the support element comprising at least some
orifices for the bolts to go through, and [0036] leveling and
attachment means for the support element to the connection
bolts.
[0037] It is also an object of the present invention a unit for the
attachment of a wind turbine to a foundation which is attainable
through the previously described process and which incorporates the
described technical characteristics of the unit for the attachment
of a tower to a foundation.
[0038] According to the aforementioned, the unit for the attachment
of a wind turbine tower to a foundation is also characterized in
that the lower side of the support element is directly connected
through adhesion to the concrete poured into the foundation hole,
due to the setting of the concrete poured into the foundation hole
being carried out when it is in contact with the support
element.
[0039] Finally, a wind turbine incorporating the unit for the
attachment of the wind turbine tower to the foundation as
previously described is also an object of this invention.
DESCRIPTION OF THE DRAWINGS
[0040] To complete the description that is being made and with the
object of helping to a better understanding of the characteristics
of the invention, in accordance with a preferred embodiment
thereof, accompanying said description as an integral part thereof,
is a set of drawings wherein, by way of illustration and not
restrictively, the following has been represented:
[0041] FIG. 1.--Shows a schematic section of an attachment between
the tower and the foundation according to the state of the art.
[0042] FIG. 2.--Shows a schematic perspective view of the
foundation hole of an onshore wind turbine which incorporates a set
of bolts and a support element located over them.
[0043] FIG. 3.--Shows a schematic section of an attachment between
tower and foundation according to a first example of preferred
embodiment of the leveling and attachment means of the support
element.
[0044] FIG. 4.--Shows a schematic section of an attachment between
the tower and the foundation according to a second example of
preferred embodiment of the leveling and attachment means of the
support element.
PREFERRED EMBODIMENT OF THE INVENTION
[0045] FIG. 1 shows an example of an attachment between a lower
section of a tower (1) and a foundation known in the state of the
art. The tower (1) is installed over the foundation which is
connected to the bolts (3) which are at the same time partially
embedded in the foundation concrete (2). Around the base of the
tower (1) there is a grout ring (20) which connects the tower (1)
to the foundation. This solution has the disadvantages previously
described.
[0046] FIG. 3 shows a preferred embodiment of an attachment unit
according to the object of the invention, which is obtained
following the process that was previously described. Represented in
the figure are: [0047] a set of connection bolts (3) for connecting
the foundation to the tower (1), [0048] a support element (10) in
contact with the tower (1) and in contact with the foundation
concrete (2). The support element (10) comprises some orifices (11)
for the connection bolts (3) to go through, and [0049] leveling and
attachment means for the support element (10), comprising at least
one threaded element (13) which is located in connection with the
support element (10) and movable relative to the connection bolts
(3), which are also threaded so that activation of the threaded
element (13) varies the elevation of the support element's (10)
orifices (11).
[0050] In this preferred embodiment of FIG. 3, the threaded
elements (13) are located in contact with the lower side of the
support element (10) and embedded in the foundation concrete
(2).
[0051] This way, the stage of leveling the support element (10)
comprises a stage for the regulation of the elevation of the
support element's (10) orifices (11) until the support element (10)
is leveled.
[0052] More precisely, in the preferred embodiment shown in FIG. 3,
the threaded elements (13) are low resistance threaded elements
(13), so that when the connection between the tower's (1) first
section and the connection bolts (3) is carried out, the tension of
the bolts (3) will lead to the rupture of the threaded elements
(13) which will break due to the connection bolt's (3) traction,
which will cause the threaded element (13) to collide against the
support element (10), causing the threads thereof (13) to break,
thus enabling traction of the connection bolt (3).
[0053] A second preferred embodiment of the leveling and attachment
means of the support element (10) is represented in FIG. 4, which
also consist of at least one threaded element (13), in particular,
there are two threaded elements (13) represented, located in
connection with the support element (10). However, in this
preferred embodiment, the threaded elements (13) are located in
contact with an intermediate element (15) which is located also
connected with the support element (10). This way, an actuation
over the threaded elements (13), provokes said threaded elements
(13) moving the intermediate element (15), which has a U shape and
whose legs are placed attached through screws (16) to the support
element (10), and thus through the screws (16) the support element
(10) is moved. The advantage of this second embodiment is that once
the support element (10) is attached, the leveling and attachment
means are removable so that they may be able to be used for
leveling in another tower, being therefore reusable.
[0054] The support element (10) could be made of a metallic
material such as mechanized steel or made of a base of elastomeric
material which has a great resilience capacity and reinforced with
a metallic material, for example with embedded plates in its
interior. This embodiment has the additional advantage of
mitigating and absorbing land vibrations, in case they are located
in seismic areas.
[0055] Additionally, in the case of the metallic support element
(10), it may comprise a sheet of elastomeric material over its
upper side which would be installed before the stage of the
installation of the tower's (1) lower section over the support
element (10).
[0056] Optionally, the support element (10) may consist of a disc
or may be divided into partially annular configured sectors (14) to
facilitate transportation and handling thereof (10).
[0057] There is also a preferred embodiment of the tower's (1)
lower section represented in FIG. 3, which itself comprises a
flange (5) with drills (6) for the introduction of connection bolts
(3) and for clamping the lower section of the tower (1) to the
support element (10) and the foundation.
[0058] FIG. 2 shows a preferred embodiment of the stage in which
the execution of positioning of, specifically, the partially
annular configuration sectors (14) over the connection bolts (3)
between the foundation and the tower (1) is performed. FIG. 2 shows
the foundation hole (4) of an onshore wind turbine and the set of
bolts (3) and the preferred embodiment in which the positioning of
the partially annular configuration sectors (14) in the connection
bolts (3) is carried out in the foundation hole (4). Optionally,
the partially annular configuration sectors (14) may be previously
installed in the set of connection bolts (3). It should be noted
that in this stage the concrete (2) has not yet been poured into
the hole (4).
[0059] For the leveling, each partially annular configuration
sector (14) comprises at least three orifices (11) for the
insertion of three bolts (3), therefore, through the action of the
three threaded elements (13) previously described, the leveling and
attachment of the partially annular configuration sectors (14) is
carried out, as well as their (14) alignment.
* * * * *