WO2010071975A1

WO2010071975A1 - Wind turbine tower and method for building the same

Info

Publication number: WO2010071975A1
Application number: PCT/CA2009/001670
Authority: WO
Inventors: Frederick Churchill
Original assignee: Organoworld Inc.
Priority date: 2008-12-23
Filing date: 2009-11-18
Publication date: 2010-07-01
Also published as: CA2647804A1

Abstract

The present invention relates to a wind turbine tower and a method for building the same. The tower of the present invention comprises a platform and a number of columns "c", the platform resting upon the columns and receiving the wind turbine. Each column "c" of the tower comprises a foundation and a plurality of adjacent stacked column sections extending from the foundation. Each pair of adjacent column sections comprises a linking flange and a reinforcing element. The linking flange itself is characterized in that it comprises an edge, a main perforation traversing the flange and a satellite perforation traversing the flange, positioned between the edge and the main perforation. The present invention also pertains to a device for providing a seal around a main perforation of the flange during the construction of the tower. This device comprises a hollow body, an inlet for receiving building materials and a vent for allowing air circulation. The method for building the tower in accordance with the present invention does not require the use of lifting cranes to hoist the column sections on top of one another. The method may also be performed on the site of construction of the tower.

Description

WIND TURBINE TOWER AND METHOD FOR BUILDING THE SAME

FIELD OF THE INVENTION

The present invention generally relates to tower construction. More specifically, the present invention relates to a tower for supporting a wind turbine and a method for building the same.

BACKGROUND OF THE INVENTION

It is generally known that wind energy is a clean, sustainable energy source. Wind energy is a pollution-free, infinitely sustainable form of energy which does not use fuel, does not produce greenhouse gases and does not produce toxic or radioactive waste.

It is also known that wind energy machines are called "wind turbine generators", "wind pumps", or more generally "wind turbines". The use of wind turbine generators is growing around the world. However, in order to meet the greater demands for energy, wind turbines are becoming larger in size to reduce the cost of electricity. Therefore, it follows that the cost of building the structures used to support the wind turbines are also becoming more costly as well as more complicated to build, on a logistical level. Indeed, it is difficult and costly to manufacture and transport the large heavy prefabricated wind turbine sections, whether they are of steel or pre-cast concrete, since the size and the weight of the tower sections has increased to support the growing size of the wind turbines. The lifting cranes required to raise and position the sections are also costly and difficult to mobilize.

It is known that large commercial wind turbines are always installed at considerable heights. Indeed, it is known that wind energy converts kinetic energy that is present in the wind into more useful forms of energy such as mechanical energy or electricity. Therefore, the amount of potential energy depends mainly on wind speed, but is also affected slightly by the density of the air, which is determined, amongst others, by the air temperature, barometric pressure, and altitude. Concerning the average wind velocity, it will increase with an increase in the height at which the wind turbine is positioned according to the 1/7™ rule. The average wind velocity will increase with an increase in height at which the wind turbine is positioned according to the 1/7™ rule. Wind power production is very dependant on wind speed, as power increases with the cube of the wind speed. As such, the higher the installation of the wind turbine, the higher will be the wind speeds experienced by the turbine and the more power will be produced. The turbines are usually installed at a height of 30 to 80 meters from the ground.

Almost all existing large wind turbines are of the three-bladed propeller Horizontal Axis Wind Turbine (HAWT) type. These turbines use a slew bearing to rotate the propeller into the wind direction. A hollow pre-cast concrete or prefabricated steel tower is traditionally used to support this type of turbine. The slew bearing sits inside the tower and the turbine sits on the top rim of the tower. The advantage of this arrangement is that the slew bearing and its drive are protected from the elements. However, the arrangement also presents disadvantages in that the sections of the tower are very heavy and require powerful cranes, to lift them to the top of the tower during construction. Transportation of the tower sections from their place of manufacture to the building site of the tower is difficult and requires special routing, special heavy load trucks, which necessarily imply high transportation costs. Therefore, as a matter of logistics, the diameter of the tower is essentially limited to the diameter of what can be transported. In limiting the diameter of the towers, the structural design of the tower will require very large foundations to accept horizontal wind thrust. Indeed, the more the wind thrust is concentrated on a small diameter, the larger and deeper will be the foundation which supports the tower.

In light of these issues, it is clear that developed world countries have been at the forefront of the installation of wind turbines. In contrast, in third world countries for example, the lack of equipment and infrastructure necessary to build, transport or erect large towers is an obstacle to the installation of wind turbines.

Therefore, in view of the above, there is a need for an improved wind turbine tower which is more versatile, easier to build on the site of its erection, and less expensive than some of the wind turbine towers already known in the art. Also, there is a need for an improved method of building wind turbine towers which is logistically simple, limits the need to transport heavy tower sections and limits the equipment required to build such a tower.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a wind turbine tower and a method for building the same which, by virtue of its design and components, satisfy some of the above-mentioned needs and is thus an improvement over other related turbine towers and/or tower building methods known in the prior art.

In accordance with the present invention, the above object is achieved, as will be easily understood, with a turbine tower and a method of building this tower such as the ones briefly described herein and such as the ones exemplified in the accompanying drawings.

In accordance a preferred embodiment of the present invention, there is provided a wind turbine tower for supporting a wind turbine, the wind turbine tower comprising a platform and a number of columns "c". The platform rests upon the columns and receives the wind turbine.

Each column "c" of the tower comprises: a foundation; a plurality of adjacent stacked column sections, a first one of the plurality of column sections resting upon the foundation, a second one of the plurality of column sections providing support to the platform, each column section having an upper surface facing the platform and a lower surface facing the foundation, each pair of adjacent column sections comprising:

-a linking flange, linking the upper and lower column sections of the pair of adjacent column sections, said linking flange having a lower face contacting the upper surface of the lower column section and an upper face contacting the lower surface of the adjacent upper column section, the linking flange comprising:

- an edge;

- a main perforation traversing the flange; and - a satellite perforation traversing the flange, positioned between the edge and the main perforation; and -a reinforcing element comprising a top end and a bottom end, the reinforcing element spanning at least two adjacent column sections, the top end of the reinforcing element being engaged into the platform and the bottom end of the reinforcing element resting on the foundation, the reinforcing element passing through the satellite perforation of the linking flange separating the adjacent column sections.

In accordance with another preferred embodiment of the present invention, there is provided a flange as described hereinabove.

Furthermore, and in accordance with yet another preferred embodiment of the present invention, there is provided a device for providing a seal around the main perforation of the flange. This device comprises: a hollow body positioned so as to provide a seal around the main perforation; - an inlet for receiving building materials, the inlet comprising a first end and a second end, the first end of the inlet being connected to the hollow body and the second end of the inlet adapted to be connected to an inlet orifice extending through the second column section to the outside surface of the second column section; and a vent for allowing air circulation, the vent comprising a first end and a second end, the first end of the vent being connected to the hollow body and the second end of the inlet adapted to be connected to a vent orifice extending through the second column section to the outside surface of the second column section.

Advantageously, this device will be used during the construction of the tower according to a method of building the same described herein below.

In accordance with another preferred embodiment of the present invention, there is provided a method for building a wind turbine tower which may be carried out using the following sequence of steps to which may be added a plurality of optional steps: a. laying a foundation; b. providing a removable hollow spacer of height hi in contact with the foundation, the hollow spacer comprising a lower surface facing the foundation and an upper surface opposite the lower surface, c. placing a linking flange (Fn) on the upper surface of the hollow spacer, at a jacking position, the linking flange comprising: an edge; a lower face perpendicular to the edge and contacting the upper surface of the hollow spacer; an upper face opposite the lower face; a main perforation traversing the flange; and a satellite perforation traversing the flange, positioned between the edge and the main perforation; d. inserting a first reinforcing element (Rn) through the satellite perforation of the linking flange (Fn), the first reinforcing element (Rn) thereby spanning a columnar unit (U_n) and the height of the spacer hi ; e. placing a mould on the upper face of the linking flange (Fn); f. positioning a device to provide a seal around the main perforation of the linking flange on the upper surface of the linking flange (Fn), the device comprising:

- a hollow body positioned so as to provide a seal around the main perforation;

- an inlet for receiving building materials or a mixture, the inlet comprising a first end and a second end, the first end of the inlet being connected to the hollow body and the second end of the inlet adapted to be connected to an inlet orifice extending through the columnar unit to the outside surface of the columnar unit (U_n); and - a vent for allowing air circulation, the vent comprising a first end and a second end, the first end of the vent being connected to the hollow body and the second end of the inlet adapted to be connected to a vent orifice extending through the columnar unit (U_n) to the outside surface of the columnar unit (Un); g. pouring a mixture into the mould as defined in step e) so as to obtain the columnar unit (U_n); h. providing a first jack and a second jack on either side of the hollow spacer, the first jack and second jack each comprising an extension arm and each being of height h2, the first and second jack being operable between a retracted position and an extended position, and the height h2 being smaller than the height hi when the first and second jack are in the retracted position; i. positioning the extension arms of the first and second jacks to support the linking flange (Fn) in the jacking position, when the first and second jacks are in the retracted position; j. operating the first jack and the second jack from the retracted position to the extended position, allowing the linking flange in the jacking position to transition to a building position, a space (Sn) being provided between the foundation and the jacking position; k. placing another linking flange (Fn+1 ), equivalent to the first linking flange (Fn), on top of the spacer;

I. placing another reinforcing element (Rn+1 ), equivalent to the first reinforcing element (Rn), through the satellite perforation of the another linking flange (Fn+1 ), the lower face of the flange in the building position receiving a top end of the another reinforcing element (Rn+1 ) and a bottom end of the another reinforcing element

(Rn+1 ) resting on the foundation; m. placing a mould on the upper face of the another linking flange

(Fn+1 ) so as to define another columnar unit (U_n+i); n. positioning another device to provide a seal around the main perforation of the another linking flange (Fn+1 ) on the upper surface of the another linking flange (Fn+1 ); o. pouring a mixture into the input of the device positioned in the columnar unit (U_n) so as to obtain another columnar unit (U_n+O as the mixture flows through the main perforation of the flange in the building position; p. operating the first and second jack from the extended position to the retracted position; q. Repeating steps (i) to (p) n number of times until a desired number of the columnar units (U_n) is reached, wherein steps (a) to (q) are performed for each of the c number of columns of the wind turbine tower.

There are several advantages to this type of turbine tower and method of building the same. The tower is built on the site of erection and no high scaffolding is required. There are no heavy cylindrical pieces or sections of the tower to be transported and then lifted to great heights with a crane.

Furthermore, the wind turbine itself can be assembled at almost ground level using small mobile equipment and subsequently erected to the desired height with the method of building the wind turbine tower described hereinabove. This is less expensive and safer than lifting the turbine components to the top of the tower for assembly, when the tower is under construction.

Therefore, in accordance with the present invention, the turbine tower and/or the method of building the same avoid the transportation and erection of large and heavy prefabricated tower sections on site. Also, the equipment needed for on-site erection of the tower is limited.

According to yet another aspect of the present invention, there is also provided a turbine tower assembly with the above-mentioned turbine tower.

According to yet another aspect of the present invention, there is also provided a kit for assembling the above-mentioned turbine tower, components and/or turbine tower assembly.

According to yet another aspect of the present invention, there is also provided a method for assembling components of the above-mentioned kit.

The objects and advantages of the present invention will become more apparent upon reading of the following non-restrictive description of preferred embodiments thereof, given for the purpose of exemplification only, with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1A shows a front view of a wind turbine tower according to a preferred embodiment of the present invention.

Figure 1 B shows a side view of the wind turbine tower of Figure 1 A.

Figure 1 C shows a front view of another wind turbine tower according to another preferred embodiment of the present invention.

Figure 1 D shows a side view of the wind turbine tower of Figure 1 C.

Figure 2A is a top view of a flange for linking columnar sections of any one of the wind turbine towers of Figures 1A to 1 D.

Figure 2B is a cross-sectional view along line B-B of the flange of Figure 2A.

Figure 2C is a cross-sectional view along line C-C of the flange of Figure 2A.

Figure 2D is another cross section of the flange of Figure 2A along line D-D, in accordance with another preferred embodiment of the invention.

Figure 3 is a schematic cross-sectional view of a column of a tower in accordance with the present invention.

Figure 4 is a cross-sectional view of the placement of a reinforcing bar relative to another reinforcing bar and a flange in a column of a tower in accordance with the present invention.

Figure 5 is a schematic cross-sectional view of a column of a tower in accordance with the present invention, in which two adjacent stacked column sections are supported on a spacer which rests upon a pedestal, the uppermost stacked column section supporting a platform for supporting a wind turbine. Figure 6 is a schematic exploded side view of a portion of the tower shown in Figure 1 B.

While the invention will be described in conjunction with example embodiments, it will be understood that it is not intended to limit the scope of the invention to such embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included, as apparent to a person skilled in the art.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

In the following description, the same numerical references refer to similar elements. The embodiments, geometrical configurations, materials mentioned and/or dimensions shown in the figures or described in the present description are preferred embodiments only, given for exemplification purposes only.

In the context of the present description, the expression "tower" includes all types of towers, structure, support structure and/or the like, as can be easily understood by a person skilled in the art. Moreover, although the present invention was primarily designed for a wind turbine, it may be used with other kinds of turbines, such as the aforementioned or others (e.g. HAWT, VAWT, etc.), as also apparent to a person skilled in the art. For this reason, the expression "turbine" should not be taken as to limit the scope of the present invention and includes all other kinds of turbines or items with which the present invention may be used and could be useful.

Moreover, in the context of the present description, the expressions "tower", "structure", "support", "system", "device", "assembly" and "product", as well as any other equivalent expressions and/or compound words thereof, may be used interchangeably. The same applies for any other mutually equivalent expressions, such as "turbine" and "mill" for example, as apparent to a person skilled in the art. In addition, although the preferred embodiment of the present invention as illustrated in the accompanying drawings comprises components, and although the preferred embodiment of the wind turbine tower and corresponding parts of the present invention as shown consists of certain geometrical configurations as explained and illustrated herein, not all of these components and geometries are essential to the invention and thus should not be taken in their restrictive sense, i.e. should not be taken so as to limit the scope of the present invention. It is to be understood, as also apparent to a person skilled in the art, that other suitable components and cooperations thereinbetween, as well as other suitable geometrical configurations may be used for the wind turbine tower according to the present invention, as will be briefly explained herein and as can be easily inferred herefrom, without departing from the scope of the invention.

A. Wind Turbine Tower

In accordance with a preferred embodiment of the present invention, and as shown in Figures 1A to 1 D, the wind turbine tower (1 ) comprises a platform (3) and a number of columns "c", each column "c" designated by the reference numeral (5). The platform (3) rests upon the total number of columns "c" (5) and receives a wind turbine (7).

As mentioned hereinabove, each column (5) of the wind turbine tower (1 ) of the present invention comprises a foundation (9). As will be understood by a person skilled in the art, the foundation (9) may be the ground or any other type of solid base, natural or artificial, on which the column rests. Advantageously, the foundation (9) is made of concrete, but can also be made of any other suitable material known in the art. It will also be understood by a person skilled in the art that each column (5) may have its own foundation (9), or, alternatively, there may be a single foundation (9) for the total number of columns "c" (5).

Advantageously, the foundation (9) is provided with a column pedestal (11 ) on which the column (5) sits. A person skilled in the art will understand that the pedestal (11 ) provides extra support to the column (5), but that the column (5) may as easily rest directly on the foundation (9).

It will be understood by a person skilled in the art that the platform (3) may be constructed from a variety of building materials such as structural steel, concrete and/or the like. Thus, the platform (3) may be suitable to receive slew bearings drives or carriages structure that rotate by motorized wheels rolling on the top of the platform (3). As such, the platform (3) may support very long turbines (7) comprising multiple rotor(s) and multiple generator(s) installed in series. Furthermore, increasing the diameter of the platform (3), the columns (5) can be placed over a larger surface area. The diameter of each one of the columns (5) is not limited to the diameter of the slew bearings of the turbine (7). In turn, the size of the foundation (9) that supports the column (5) is decreased. By expanding the surface area on which the columns (5) are erected to form a tower (1 ), the horizontal wind thrusts are absorbed by a much smaller mass of the foundation (9).

As shown in Figure 3, each column (5) further comprises a plurality of adjacent column sections, each column section identified as reference numeral (13), stacked one upon the other. A first one of the plurality of column sections rests upon the foundation (9) and a second one of the plurality of column sections (13) provides support to the platform (3). Each one of the column sections has an upper surface facing the platform (3) and a lower surface facing the foundation (9).

For the purposes of the present invention, a person in the art will understand that the first one of the plurality of column sections may be a spacer (51 ) while the column (5) is in the process of being built, advantageously in accordance with the method that will described herein below. Of course, it is understood that once the column (5) has attained its desired height, the space defined by the spacer (51 ) will be replaced by or filled with building material in order to enhance the structural integrity of the column (5). Still as shown in Figure 3, each pair of adjacent column sections (13) further comprises a linking flange (15), linking the upper and lower column sections (13) of the pair of adjacent column sections. This linking flange (15) has a lower face contacting the upper surface of the lower column section, or spacer (51 ), and an upper face contacting the lower surface of the adjacent upper column section (13).

As shown in Figures 2A to 2C, the linking flange (15) comprises an edge (17), a main perforation (19) traversing the flange (15); and a satellite perforation (21 ) traversing the flange, positioned between the edge (17) and the main perforation (19).

A person skilled in the art will understand that the edge (17) of the flange (15) may be round, straight or of any other form suitable for the purpose of the present invention.

Advantageously, and as shown in Figure 2D, the linking flange (15) comprises a depression (23) adjacent to the satellite perforation (21 ), and thus positioned between the edge (17) and the main perforation (19), the depression (23) being in the lower face of the flange (15). Advantageously also, another depression may additionally be positioned in the upper face of the flange (15), opposite to the depression (23) in the lower face of the flange (15). The depression (23) is designed so as to receive a reinforcing element (41 ) as will be described herein below and to prevent lateral movement of this reinforcing element (41 ).

Also advantageously, the flange (15) may comprise a plurality of depressions (23) and satellite perforations (21 ) positioned in alternation.

Further advantageously, the linking flange (15) comprises a groove. This groove may be present on both of the upper face and the lower face of the linking flange (15). The groove is designed so as to hold a mould in place. However, a person skilled in the art will understand that the moulds may be held in place by any type of attachment means such as straps, hinges, and/or the like. The attachment means may also cover the part of the mould which is in contact with the flange (15) and overlap part of the edge (17) of the flange (15). The groove will also advantageously limit the leaking of the mixture or building materials when this mixture is poured to form the columnar section (13) or columnar unit.

Advantageously, the flange (15) is larger than the column section (13). As such, a lip will be formed by the part of the flange (15) which extends beyond the column section (13). The flange (15) also advantageously provides a connection point for cross bracing between columns (5).

Each pair of adjacent column sections (13) further comprises a reinforcing element (41 ). This reinforcing element (41 ) comprises a top end (43) and a bottom end (45) and spans at least two adjacent column sections (13), or, as shown in Figure 3, spans a column section (13) and the space defined by the spacer (51 ). As will be understood by a person skilled in the art, the reinforcing element (41 ) may also be called a "rebar" or "reinforcing bar". The reinforcing element (41 ) is advantageously made of steel or any other type of metal, and may comprise several sub-elements which are important to ensure the structural integrity of the reinforcing element (41 ). Therefore, a person skilled in the art will understand that the reinforcing bar (41 ) does not have to be a single element; it can comprise a plurality of elements tied together.

As shown in Figure 3, the top end (43) of the reinforcing element (41 ) may abut the platform (3), or an additional support structure (31 ) which has been added in order to further support the platform (3). The bottom end (45) of the reinforcing element (41 ) rests on the foundation (9), on the pedestal (11 ) or on an additional support structure (33) which has been laid upon the foundation (9) or the pedestal (11 ). As such, and as shown in Figure 4, the reinforcing element (41 ) passes through the satellite perforation (21 ) of the linking flange (15) separating the adjacent column sections (13).

Of course, a person skilled in the art will understand that the foundation (9), the pedestal (11 ) and/or the platform (3) may be provided with a cupped portion in order to receive the top end (43) or the bottom end (45) of the reinforcing element may be provided with a cupped portion in order to receive the top end (43) or the bottom end (45) of the reinforcing element (41 ). This cupped portion will advantageously stabilize the reinforcing element (41 ). Alternatively, a person skilled in the art will also understand that the reinforcing element (41 ) may be stabilized by using other means such as wire, glue and/or the like.

As shown in Figure 5, the columns (5) of the wind turbine tower (1 ) may comprise a plurality of adjacent column sections (13). As will further be described herein below, when the first one of the plurality of column sections (13) is raised, another linking flange, equivalent to the flange (15) described hereinabove, is positioned so that the satellite perforation (21 ) of the another linking flange engages another reinforcing element (47), this another reinforcing element (47) being equivalent to the reinforcing element (41 ) described hereinabove. The bottom end of the another reinforcing element (47) may abut the foundation (9), the pedestal (11 ) or the additional support (33). Advantageously, and as shown in Figure 4, the top end of the another reinforcing element (47) may abut the lower face of the linking flange (15). Advantageously also, and as still shown in Figure 4, the reinforcing element (41 ) and the another reinforcing element (47) will be adjacent to one another. Advantageously, the reinforcing element (41 ) and the another reinforcing element (47) are continuous in length and do not contain splices. Also advantageously, they are of same length. This will simplify the building of the column (5).

B. Method for Building the Wind Turbine Tower In accordance with another preferred embodiment of the present invention, there is provided a method for building a wind turbine tower (1 ), such as the wind turbine tower described hereinabove.

This method for building a wind turbine tower (1 ) which comprises a number of columns "c" (5) and a platform (3) for receiving a wind turbine (7), the platform (3) resting atop the number of columns "c" (5), comprises a step (a) of laying a foundation (9) to support the column (5).

As mentioned hereinabove, the laying of the foundation (9) advantageously includes the laying of a pedestal (11 ) upon the foundation (9) and/or the laying of an additional support structure (33) on the foundation (9) or the pedestal (11 ). Also advantageously, the foundation (9) may comprise a base contacting the ground and a pedestal (11 ) positioned on top of the base. Further advantageously, the platform (3) may comprise a deck.

Advantageously, the tower (1 ) consists of multiple columns (5) which are supported by one another through a cross brace (4) shown in Figure 1 A to 1 D.

In a step (b), the removable hollow spacer (51 ) of height hi is provided, the spacer (51 ) being in contact with or placed upon the foundation (9). This hollow spacer (51 ) thus comprises a lower surface facing the foundation (9) and an upper surface opposite the lower surface.

Advantageously, the spacer (51 ) is made of steel and is designed to absorb the loads and thrusts of each column (5). The upper surface of the spacer (51 ) is preferably annular in shape.

In a step (c), the linking flange (Fn), equivalent to the linking flange (15) described hereinabove and as shown in Figures 2A to 2D, is placed on the upper surface of the hollow spacer (51 ), at a jacking position. The jacking position may be defined as the position at which the linking flange (Fn) is placed in order to be jacked up to a building position, in accordance with a step of the method yet to be defined.

Advantageously, the linking flange (Fn) may be made of any material that has the tensile strength to absorb the bending moment experienced during extension of the jacks (81a, 81b). It will be understood that for aesthetic reasons, the material should be one which is rust-resistant and/or rust-proof. Examples of such materials include, but are not limited to plastics, polyethylene, aluminium and stainless steel.

In a step (d), a first reinforcing element (Rn), equivalent to the reinforcing element (41 ) as defined hereinabove, is inserted through the satellite perforation (21 ) of the linking flange (Fn). As such, the first reinforcing element (Rn) spans a columnar unit (U_n) and the height hi of the spacer (51 ).

As will be understood by a person skilled in the art, the columnar unit (U_n) corresponds to the column section (13) as described hereinabove.

In a step (e), a mould is placed on the upper face of the linking flange (Fn). This mould may comprise a body which is in two pieces and which fits around the reinforcing element (41 ). As will be known to a person skilled in the art, the mould can be in aluminium, cardboard, wood plastic or any other suitable material. Advantageously, aluminium and stainless steel are selected for the mould as they can be left in place after a mixture is poured and will serve to protect the mixture of the columns from the elements while this mixture sets.

When the method of the present invention is realized, a person skilled in the art will understand that the platform (3) will be installed and the turbine (7) set upon the platform (3) when the columns (5) of the tower (1 ) are still at a low level, i.e. when the columns (5) undergoing construction are still close to the ground. As such, the use of cranes and other equipment necessary to lift the platform (3) and the turbine (7) will be minimized. Also, if desired, the turbine (7) may be set up on- site, on top of the platform (3), upon erecting the tower (1 ).

In the case where long propeller type blades are used, the first blade can be bolted in place. The two remaining blades can be attached to a frame located directly under the end of the rotor shaft that will allow their bolting in place once the platform is sufficiently raised. This same frame can later be used to remove a blade(s).

In a step (f), a device (60) is positioned to provide a seal around the main perforation of the linking flange (Fn) on its upper surface. As shown on Figures 3 and 5, this device (60) comprises: a hollow body (61 ) positioned so as to provide a seal around the main perforation of the linking flange (Fn); an inlet (63) for receiving building materials, the inlet (63) comprising a first end (65) and a second end (67), the first end (65) being connected to the hollow body (61 ) and the second end (67) of the inlet (63) adapted to be connected to an inlet orifice extending through the columnar unit (U_n) to an outside surface of the columnar unit (U_n); and a vent (71 ) for allowing air circulation, the vent (71 ) comprising a first end (73) and a second end, the first end (73) being connected to the hollow body (61 ) and the second end adapted to be connected to a vent orifice (77) extending through the columnar unit (U_n) to the outside surface of the columnar unit (U_n).

As such, a person skilled in the art will understand that the device (60) for providing a seal around a main perforation of the linking flange (Fn) is a device that is used when the flange (Fn) links a first and second adjacent stacked column sections of a column under construction, the second column section being stacked on top of the first column section, each column section being provided with an outside surface, an upper surface and a lower surface, with the flange (Fn) having a lower face contacting the upper surface of the first column section and an upper face contacting the lower face of the second column section. The device (60) seals the main perforation of the flange (Fn) and provides an inlet (63) for allowing the mixture to be inserted or pumped into the mould and a vent (71 ) for allowing air to leave the mould and thereby improving the time required for the mixture to set. The vent (71 ) further ensures that no air pockets remain in the mixture once the latter has been pumped into the mould. Of course, the filing of the mould with the mixture and the venting of the mixture once it has been poured may be accomplished by other means. The inlet (63) and the vent (71 ) may also advantageously be one and the same.

Advantageously, the device (60) can be made of many types of materials such as, but not limited to metals, plastics and composite materials. Advantageously also, the device (60) is conical in shape. This shape is advantageous in that it allows a stronger connection to be made between successive columnar units (U_n). The device may also take many hollow forms. As will be understood by a person skilled in the art, the device (60) may also be circular in shape and/or be designed so as to include a depression. Further advantageously, the device may comprise grooves on its surface.

In a step (g), the mixture is poured into the mould so as to obtain the columnar unit (U_n). Advantageously, this mixture is a concrete mixture suitable to be used for building turbine towers. A person skilled in the art will understand that any other types of mixtures suitable for constructing a tower may also by used. Advantageously, the platform (3) may be placed on top of the columnar unit (U_n) after this step (g) of the method has been completed.

In a step (h) of the method of the present invention, a first jack (81a) and a second jack (81 b) are, or have already been, secured to the foundation (9) and/or the pedestal (11 ), on either side of the hollow spacer (51 ). Advantageously, the jacks (81 a, 81 b) will be secured to the foundation (9) and/or the pedestal (11 ) by way of securing means, such as bolts for example. A person skilled in the art will understand that the foundation (9) and/or the pedestal (11 ) of each foundation (9) is adapted in size so as to allow the securing of the jacks (81 a, 81 b) in a suitable position. The first and second jacks (81 a, 81 b) are also of a height h2 which is smaller than the height hi of the spacer (51 ) when the first and second jacks (81a, 81 b) are in the retracted position. Advantageously, the first and second jacks (81 a, 81 b) are equivalent and may be hydraulic jacks. However, a person skilled in the art will know that other types of jacks may be used with the same purpose and without limiting the scope of the present invention. Further advantageously, the first and second jacks (81a, 81b) are telescopic.

The first jack (81 a) and second jack (81 b) each comprise an extension arm. The extension arm of the first and second jacks (81 a, 81 b) must be resilient enough to support the linking flange (Fn) in the jacking position.

The jacks (81 a, 81 b) are operable between a retracted position and an extended position.

As such, in a step (i) of the method of the present invention, the extension arms of the first and second jacks (81 a, 81 b) are positioned so as to support the linking flange (Fn) in the jacking position when the first and second jacks (81 a, 81 b) are in the retracted position. Advantageously, the extension arms are fitted around the exposed edges of the flange (Fn).

In a step (j), the first jack and the second jacks (81 a, 81 b) are operated from the retracted position to the extended position, allowing the linking flange (Fn) in the jacking position to transition to a building position. In doing so, a space (Sn) is provided between the foundation (9) and the linking flange (Fn) in the building position.

In a step (k), another linking flange (Fn+1 ), equivalent to the first linking flange (Fn), is placed on top of the spacer (51 ). In a step (I), another reinforcing element (Rn+1 ), equivalent to the first reinforcing element (Rn), is placed through the satellite perforation of the another linking flange (Fn+1 ), the top end of the another reinforcing element (Rn+1 ) abutting on the lower face of the flange in the building position and the bottom end of the another reinforcing element (Rn+1 ) abutting on the foundation (9) and/or the pedestal (11 ). The reinforcing elements that extend into the spacer (51 ) support the weight of the column (5) during the time required to lower the jacks (81a, 81 b) and reset their extension arms relative to the flange in the jacking position.

In a step (m), a mould is placed on the upper face of the another linking flange (Fn+1 ) so as to define another columnar unit (U_n+i).

Subsequently, in a step (n), another device to provide a seal around the main perforation of the another linking flange (Fn+1 ) is positioned on the upper surface of the another linking flange (Fn+1 ).

In a step (o), the mixture is poured or pumped into the input (63) of the device (61 ) positioned so as to cover the main perforation of the flange (Fn) in the building position, and as the mixture flows through the main perforation of the flange (Fn) in the building position and sets therein, another columnar unit (U_n+O will be obtained. It is understood in the context of the present invention that the term "set" as it applies to the mixture or to concrete means that the mixture has hardened or solidified and/or that it has hardened sufficiently for the columnar unit (U_n) to be raised.

In a step (p), the first and second jacks (81a, 81 b) are operated from the extended position to the retracted position. The reinforcing bar (41 ) and the another reinforcing bar (47) are now temporarily supporting the weight of the column (5).

In a step (q), steps (i) to (p) are repeated "n" number of times, until a desired number of the columnar units (U_n) is reached. This "desired number" will be determined by the desired height of the column (5) and/or the height at which the turbine (7) will be positioned.

It is to be understood that steps (a) to (q) of the method of the present invention are performed for each of the "c" number of columns (5) of the wind turbine tower

(1 ). This number may vary according to the size of the wind turbine (7), the size of the platform (3) supporting the wind turbine (7), etc. Advantageously, "c" has a value of at least 2. It may be desirable that the diameter of the columns varies for a given tower to reduce the material required and improve aesthetics. This is achieved by using progressively larger jacking whose thickness is increased.

Also, a person skilled in the art will note that no lifting crane is necessary for raising tower sections according to the method of the present invention.

The method of constructing a wind turbine tower as described hereinabove further advantageously comprises a step (n) of operating the first jack (81a) and the second jack (81 b) from the retracted position to the extended position, allowing the flange in the jacking position to transition to a building position, inserting another flange in the jacking position, removing the spacer, inserting the mould in the space between the flange in the jacking position and the foundation (9), and pouring the mixture to fill the space. Alternatively, the method comprises a step (^) of operating the first jack and the second jack from the retracted position to the extended position and pouring the mixture into the spacer.

Advantageously, and as shown in Figure 6, the tower (1 ) may comprise a hollow space (81 ) formed by the columns (5) which support the turbine (7). In this space (81 ), means to access the platform (83), such as stairs or an elevator for example, may be provided in order to allow access to the platform (3) and to the wind turbine (7) for maintenance and repairs thereof, for example. Depending on the size of the turbine (7), the hollow space (81 ) may be reinforced to resist wind thrust and support the entire weight of the platform (3) and turbine (7). The number "n", size and disposition of the columns "c" are designed for each tower (1 ) based on dead loads, live loads, wind thrust, seismic rating, etc.

As a person skilled in the art will understand, a plurality of types of axial flow or horizontal axis turbines may be supported by the tower of the present invention. All types of turbine whether Vertical Axis Wind Turbine (VAWT) or Horizontal Axis Wind Turbine (HAWT) can be installed on the platform and tower. It is extremely well suited for very large turbines using augmentation devices and multiple rotors and multiple generators. These larger turbines will have increased horizontal wind thrust given their size. Also for a plurality of wind turbines, different combinations and permutations of turbines may be used and supported by the wind turbine tower of the present invention, for example if a different number and/or configuration of the columns "c", is used.

As a person skilled in the art will also understand that the tower and method for building the same as described in the present invention will be adapted to wind and site locations, construction conditions, environment and the turbine itself.

The tower columns can be installed or constructed on a large surface. This would be impractical for rolled steel plate or pre-cast concrete towers. The large surface available for installation or construction is important for accepting horizontal wind thrust. By increasing the surface of installation or construction of the columns they can be of smaller diameter and installed on much smaller foundations. The requirements for load bearing capacity under the foundations are also reduced as the surface available for installation or construction increases.

Although a preferred embodiment of the present invention has been described in detail herein and illustrated in the accompanying drawings, it is to be understood that the invention is not limited to this embodiment and that various changes and modifications could be made without departing form the scope and spirit of the present invention.

Claims

1. A flange for linking a first and second adjacent stacked column sections of a column, each column section being provided with an upper surface and a lower surface, said flange having a lower face contacting the upper surface of the first column section and an upper face contacting the lower face of the second column section, the flange comprising:

- an edge;

- a main perforation traversing the flange; and - a satellite perforation traversing the flange, positioned between the edge and the main perforation.

2. The flange according to claim 1 , wherein the flange further comprises a depression, adjacent to the satellite perforation on the lower face of the flange, positioned between the edge and the main perforation.

3. The flange according to claim 1 or 2, wherein the flange comprises a plurality of depressions and satellite perforations positioned in alternation.

4. The flange according to any one of claims 1 to 3, wherein the flange further comprises a groove for receiving a mould, the groove being positioned between the edge and the satellite perforation.

5. A device for providing a seal around a main perforation of a flange, the flange linking a first and second adjacent stacked column sections of a column, the second column section being stacked on top of the first column section, each column section being provided with an outside surface, an upper surface and a lower surface, said flange having a lower face contacting the upper surface of the first column section and an upper face contacting the lower face of the second column section, the device comprising: i. a hollow body positioned so as to provide a seal around the main perforation; ii. an inlet for receiving building materials, the inlet comprising a first end and a second end, the first end of the inlet being connected to the hollow body and the second end of the inlet adapted to be connected to an inlet orifice extending through the second column section to the outside surface of the second column section; and iii. a vent for allowing air circulation, the vent comprising a first end and a second end, the first end of the vent being connected to the hollow body and the second end of the inlet adapted to be connected to a vent orifice extending through the second column section to the outside surface of the second column section.

6. The device according to claim 5, wherein the hollow body of the device is conical in shape.

7. The device according to claim 5 or 6, wherein the device comprises a plurality of grooves on its surface.

8. The device according to any one of claims 5 to 7, wherein the input and the vent are one and the same.

9. The device according to any one of claims 5 to 8, wherein the flange is the one defined in any one of claims 1 to 4.

10. The device according to claim 9, wherein the flange further comprises a depression, adjacent to the satellite perforation on the lower face of the flange, positioned between the edge and the main perforation.

11. The device according to claim 9 or 10, wherein the flange comprises a plurality of depressions and satellite perforations positioned in alternation.

12. The device according to any one of claims 9 to 11 , wherein the flange further comprises a groove for receiving a mould, the groove being positioned between the edge and the satellite perforation.

13. A wind turbine tower for supporting a wind turbine, the wind turbine tower comprising a platform and a number of columns "c", the platform resting upon the columns and receiving the wind turbine, each column comprising: i. a foundation; ii. a plurality of adjacent stacked column sections, a first one of the plurality of column sections resting upon the foundation, a second one of the plurality of column sections providing support to the platform, each column section having an upper surface facing the platform and a lower surface facing the foundation, each pair of adjacent column sections comprising: -a linking flange, linking the upper and lower column sections of the pair of adjacent column sections, said linking flange having a lower face contacting the upper surface of the lower column section and an upper face contacting the lower surface of the adjacent upper column section, the linking flange comprising:

- an edge; - a main perforation traversing the flange; and

- a satellite perforation traversing the flange, positioned between the edge and the main perforation; and -a reinforcing element comprising a top end and a bottom end, the reinforcing element spanning at least two adjacent column sections, the top end of the reinforcing element abutting the platform and the bottom end of the reinforcing element abutting the foundation, the reinforcing element passing through the satellite perforation of the linking flange separating the adjacent column sections.

14. The wind turbine tower according to claim 13, wherein "c" has a value of at least 2.

15. The wind turbine tower according to claim 13 or 14, wherein the flange further comprises a depression, adjacent to the satellite perforation on the lower face of the flange, positioned between the edge and the main perforation.

16. The wind turbine tower according to any one of claims 13 to15, wherein, when the first one of the plurality of column sections is raised, another linking flange is positioned, the satellite perforation of the another linking flange engaging another reinforcing element and the top end of the another reinforcing element being abutting the lower face of the linking flange and the bottom end of the another reinforcing element abutting the foundation.

17. The wind turbine tower according to claim 16, wherein the reinforcing element and the another reinforcing element are adjacently positioned.

18. The wind turbine tower according to any one of claims 13 to 17, wherein the flange further comprises a plurality of depressions and satellite perforations positioned in alternation.

19. The wind turbine tower according to any one of claims 13 to 18, the flange further comprising a groove for receiving a mould, the groove being positioned between the edge and the satellite perforation.

20. A method for building a wind turbine tower, the wind turbine tower comprising a number of columns "c" and a platform for receiving a wind turbine, the method comprising the steps of: a. laying a foundation; b. providing a removable hollow spacer of height hi in contact with the foundation, the hollow spacer comprising a lower surface facing the foundation and an upper surface opposite the lower surface, c. placing a linking flange (Fn) on the upper surface of the hollow spacer, at a jacking position, the linking flange comprising: an edge; a lower face perpendicular to the edge and contacting the upper surface of the hollow spacer; - an upper face opposite the lower face; a main perforation traversing the flange; and a satellite perforation traversing the flange, positioned between the edge and the main perforation; d. inserting a first reinforcing element (Rn) through the satellite perforation of the linking flange (Fn), the first reinforcing element

(Rn) thereby spanning a columnar unit (U_n) and the height of the spacer hi ; e. placing a mould on the upper face of the linking flange (Fn); f. positioning a device to provide a seal around the main perforation of the linking flange on the upper surface of the linking flange (Fn), the device comprising: i. a hollow body positioned so as to provide a seal around the main perforation; ii. an inlet for receiving building materials, the inlet comprising a first end and a second end, the first end of the inlet being connected to the hollow body and the second end of the inlet adapted to be connected to an inlet orifice extending through the columnar unit to the outside surface of the columnar unit (U_n); and iii. a vent for allowing air circulation, the vent comprising a first end and a second end, the first end of the vent being connected to the hollow body and the second end of the inlet adapted to be connected to a vent orifice extending through the columnar unit (U_n) to the outside surface of the columnar unit (U_n); g. pouring a mixture into the mould as defined in step e) so as to obtain the columnar unit (U_n); h. providing a first jack and a second jack on either side of the hollow spacer, the first jack and second jack each comprising an extension arm and each being of height h2, the first and second jack being operable between a retracted position and an extended position, and the height h2 being smaller than the height hi when the first and second jack are in the retracted position; i. positioning the extension arms of the first and second jacks to support the linking flange (Fn) in the jacking position, when the first and second jacks are in the retracted position; j. operating the first jack and the second jack from the retracted position to the extended position, allowing the linking flange in the jacking position to transition to a building position, a space (Sn) being provided between the foundation and the jacking position; k. placing another linking flange (Fn+1 ), equivalent to the first linking flange (Fn), on top of the spacer;

I. placing another reinforcing element (Rn+1 ), equivalent to the first reinforcing element (Rn), through the satellite perforation of the another linking flange (Fn+1 ), the lower face of the flange in the building position receiving a top end of the another reinforcing element (Rn+1 ) and a bottom end of the another reinforcing element (Rn+1 ) abutting the foundation; m. placing a mould on the upper face of the another linking flange

(Fn+1 ) so as to define another columnar unit (U_n+1); n. positioning another device to provide a seal around the main perforation of the another linking flange (Fn+1 ) on the upper surface of the another linking flange (Fn+1 ); o. pouring a mixture into the input of the device positioned in the columnar unit (U_n) so as to obtain another columnar unit (U_n+i); p. operating the first and second jack from the extended position to the retracted position; q. Repeating steps (i) to (p) n number of times until a desired number of the columnar units (U_n) is reached, wherein steps (a) to (q) are performed for each of the "c" number of columns of the wind turbine tower.

21 . The method according to claim 19, wherein the flange further comprises a depression adjacent to the satellite perforation, between the edge and the main perforation.

22. The method according to claim 19 or 20, wherein the flange further comprises a groove for receiving a mould, the groove being positioned between the edge and the satellite perforation.

23. The method according to any one of claims 19 to 21 , wherein the method comprises an additional step, after step (g), of placing the platform on top of the columnar unit (U-i).

24. The method according to claim any one of claims 20 to 23, wherein the method comprises a step (P₁) of operating the first jack and the second jack from the retracted position to the extended position, allowing the flange in the jacking position to transition to a building position, inserting another flange in the jacking position, removing the spacer, inserting the mould in the space between the flange in the jacking position and the foundation, and pouring the mixture to fill the space.

25. The method according to any one of claims 20 to 23, wherein the method comprises a step (r₂) of operating the first jack and the second jack from the retracted position to the extended position and pouring the mixture into the spacer.

26. The method according to any one of claims 20 to 25, wherein the mixture is a concrete mixture.

27. The method according to any one of claims 20 to 26, wherein steps (k) to (p) are performed once the mixture poured in step (o) has set.

28. The method according to any one of claims 20 to 27, wherein the first jack and the second jack are telescopic hydraulic jacks.

29. The method according to any one of claims 20 to 28, wherein the foundation comprises a base contacting the ground and a pedestal positioned on top of the base.

30. The method according to any one of claims 20 to 29, wherein the upper surface of the hollow spacer is annular.

31. The method according to any one of claims 20 to 30, wherein the number of columns "c" is dependant on platform size.

32. The method according to any one of claims 20 to 31 , wherein a bracing element is positioned between two adjacent columns of the "c" number of columns.

33. The method according to any one of claims 20 to 32, wherein the wind turbine tower comprises an additional column, positioned under the platform, and designed so as to allow an access to the platform.

34. The method according to any one of claims 20 to 33, wherein the wind turbine is chosen among a vertical axis wind turbine (VAWT) and a horizontal axis wind turbine (HAWT).

35. The method according to any one of claims 20 to 34, wherein the platform further comprises a deck.

36. The method according to any one of claims 20 to 35, wherein the wind turbine tower is built on-site.

37. The wind turbine tower built in accordance with the method defined in any one of claims 20 to 36.