WO2011135172A1

WO2011135172A1 - Method for assembling a wind turbine tower on an erection foundation and a device

Info

Publication number: WO2011135172A1
Application number: PCT/FI2011/050357
Authority: WO
Inventors: Jouko JÄRVI; Heikki Kankkunen
Original assignee: Consolis Technology Oy Ab
Priority date: 2010-04-27
Filing date: 2011-04-20
Publication date: 2011-11-03
Also published as: WO2011135172A4; FI20105460A0; EP2563994A4; EP2563994B1; FI20105460L; EP2563994A1

Abstract

A method for assembling a wind turbine tower on an erection foundation, in which method at least two ring elements, as high as part of the tower, are composed from concrete segments, and the ring elements are lifted in the assembly order to superimposed positions. The first ring element is lifted in an upright position to the vertical position of the next ring element, and locked at that height. The following ring elements are placed individually in the assembly order below the previous ring element and lifted with the previous ring element or the ring elements to the vertical position of the next ring element, and locked at that height. The last ring element is lifted into contact with the previous ring element and released connected together to hanging suspended state, and the superimposed ring elements are lowered onto the erection foundation. In addition the invention relates to the device for assembling a wind turbine tower on an erection foundation.

Description

METHOD FOR ASSEMBLING A WIND TURBINE TOWER ON AN ERECTION FOUNDATION AND A DEVICE

The invention relates to a method for assembling a wind turbine tower, wherein the wind turbine tower is assembled from concrete ring elements with the help of an assembly table, a multifunctional carriage and an assembly device. In addition the invention relates to the device used for assembly.

Wind turbines are important sources of renewable energy and the number of wind turbines is growing rapidly. Wind turbines will be more effective when built higher than today, which will increase the challenges of building wind turbine towers.

Wind turbine towers are traditionally made of steel or concrete. The use of steel, especially in high towers, is problematic because of the large diameter they require, therefore transporting parts to the construction site is difficult. Similarly, vibration of the steel structure may restrict its use in high towers. Concrete structures are made either by casting on site or in factory-made prefabricated elements. The very time-consuming casting on site contains plenty of phases and is sensitive to weather conditions. Factory-prefabricated concrete elements are transported to the worksite in parts and are assembled on site using a crane.

One method for assembling the tower from prefabricated concrete elements is presented in patent application FI 201051 16, where the tower part consists of sections assembled from concrete elements, which are placed on top of each other to form the tower. To assist in assembling the sections, a building base is used, on which base the precast concrete elements are positioned and their seams concreted. After the seam concrete of the section has cured, it is lifted onto the foundations and sections are added until the tower is completed. The problem in the above described methods for assembling wind turbine towers is the capacity requirements for the cranes needed to assemble still higher wind turbine towers. Lifting parts of the towers rising to over a hundred meters into place requires effective cranes, the transportation, assembly and use of which consume time, resources and money. The aim of the present invention is to remove the above-mentioned disadvantages. In the solution according to the invention, the wind turbine tower is assembled on an erection foundation, whereby at least two ring elements, as high as part of the tower, are composed from concrete segments, and the ring elements are lifted into superimposed positions in the order of assembly. The first ring element is lifted in an upright position to the vertical position of the next ring element, and locked at that height. The following ring elements are placed individually in the assembly order below the previous ring element and lifted with the previous ring element or the ring elements the height of the next ring element, and locked at that height. The last ring element is lifted into contact with the previous ring element and released connected together to a suspended state, and the superimposed ring elements are lowered onto the erection foundation.

The device for assembling the wind turbine tower on the erection foundation comprises the installation path, the assembly table, the multifunctional carriage and the assembly device on the erection foundation. In addition, a crane movable on the installation path can be used.

More precisely, the method according to the invention is characterized by what is stated in the characterizing part of claim 1 and the device according to the invention is characterized by what is stated in the characterizing part of claim 7.

The invention and its details will be described in more detail in the following, with reference to the enclosed drawing, wherein

Fig. 1 shows one assembly phase of a wind turbine tower according to the invention, where the ring element is assembled on the erection foundation,

Fig. 2 shows one other assembly phase of a wind turbine tower according to the invention, where a ring element is assembled on the erection foundation,

Fig. 3 shows an assembly phase of a wind turbine tower according to the invention,

Fig. 4 shows an assembly phase of a wind turbine tower according to the invention, where the generator is being installed,

Fig. 5 shows an assembly phase of a wind turbine tower according to the invention, where the steel part of a hybrid tower is being installed, Fig. 6 shows an assembly phase of a wind turbine tower according to the invention, where the blades of the generator are being installed,

Fig. 7 shows an assembly phase of a wind turbine tower according to the invention, where the multifunctional carriage is shown from the front in its lower and upper positions; and

Fig. 8 shows an assembly phase of a wind turbine tower according to the invention, where the multifunctional carriage is shown from the side in its lower and upper positions. Figure 1 illustrates one assembly phase of a wind turbine tower according to the invention, where the ring element 1 is assembled on the assembly table 5. From now on, the wind turbine tower is called the tower. The tower consists of the ring elements 1 assembled on the site, which elements are assembled from concrete segments 2 of the same height as the ring element 1. The segments 2 have been transported from a production site to a location next to the tower, where the actual assembly of the tower occurs.

In the first phase, the installation path 3 is assembled on the installation site, either on the other or on both sides of the tower foundations. The installation path 3 serves as a platform for assembling the ring elements and for transferring them to underneath the actual tower assembly device 4. The installation path 3 includes rails for the assembly tables 5 required for assembling the ring elements 1 , for the gantry crane 7 (Figure 2) and for the

multifunctional carriage 6.

In the assembly table 5 is the stencil for the segments 2 to be installed and for the binding points of the installation support struts for supporting the segments 2. The ring-shaped assembly table 5 is open in the middle and placed high enough, so that the scissor platform crane 13 is able to move inside the assembled ring element 1 and to make the necessary joints and buildups between the segments 2, such as the drillings and the fasteners required for the lift, the ladders and other equipment of the tower.

After the installation path 3 is assembled, the assembly tables 5 for the ring elements 1, the gantry crane 7 and the multifunctional carriage 6 are lifted on top of the installation path 3. Thereafter the actual assembly device 4 is assembled, which combines already assembled and joined ring elements 1 to form the tower. The assembly device 4 consists of frame guide columns 10 , locking collars 1 1 climbing along the guide columns 10 and the upper locking ring 9 used for suspending the tower, where the movable locking arms 12 are located radially in a circular fashion. Figure 2 shows the assembly of the ring element 1 from the concrete segments 2 at the working site on the assembly table 5 on top of the installation path 3 with the aid of gantry crane 7 and turning device 8. The seams of the completed ring element 1 are soldered to produce a monolithic structure. Instead of the gantry crane 7, the ring elements 1 can also be assembled using the standard crane according to Figure 1. After the assembly, the multifunctional carriage 6 moves under the ring element 1 , raises it up together with the assembly table 5 and moves the ring element 1 and the assembly table 5 over the foundations of the tower under the tower assembly device 4. The multifunctional carriage 6 has driving motors and wheels under the longitudinal beams for transport and hydraulic cylinders for lifting the ring element 1.

Figure 3 shows the assembly of the tower in assembly device 4, from top to bottom in reverse order, so that the upper ring element 1 of the tower is installed first, and under it the lower ring elements 1 are threaded one by one. Before the actual tower assembly it is possible to install and fasten the required adapter 15 (Figure 4) on top of the topmost, assembled ring element 1 between the wind turbine generator 14 and the ring element 1. The adapter 15 may also be installed at a later stage, for example, during installation of the generator 14.

The tower assembly begins when, below the assembly device 4 in multifunctional carriage 6 on assembly table 5, the top ring element 1 is lifted into an upright position using the locking collars 1 1 climbing up along the assembly device 4. The lifted ring element 1 is locked into place in its raised position with the aid of locking arms 12 of the locking ring 9 located on the top part of the assembly device 4. At the lower part of the ring element are provided mounting holes which the extensions of the locking arms 12 engage. After the locking, the multifunctional carriage 6 and the assembly table 5 are taken down with the help of locking collars 1 1 , and the multifunctional carriage 6 repositions assembly table 5 and leaves to pick up a new ring element 1.

The other ring elements 1 to be located below the top ring element 1 will be lifted one by one with the aid of the locking collars 1 1 into contact with ring element 1 above and attached to each other. Thus, the ring elements of the tower thus formed are raised to the upper position with the help of the locking collars 1 1 and locked into place using locking arms 12. The multifunctional carriage 6 and the assembly table 5 are taken down with the help of locking collars 1 1 and the multifunctional carriage 6 repositions assembly table 5 and leaves to pick up a new ring element 1.

The bottom tower ring element 1 on the assembly table 5 of multifunctional carriage 6 is raised using locking collars 1 1 into contact with the above tower and is suspendenly attached to the tower above. The multifunctional carriage 6 and the assembly table 5 are taken down with the help of the locking collars 1 1 and moved outside of the tower. The locking collars 1 1 are lifted to align with fastening holes located in the lower part or close to the lower part of the lowest ring element 1 , and the extensions of locking collars 1 1 engage the locking holes of the lower part of the ring element 1. Subsequently, locking arms 12 located at the top of the assembly device 4, which arms have been supporting the tower, are released whereby the full weight of the tower is shifted to the locking collars 1 1. Finally, the finished tower is lowered as a whole onto the foundations with the help of locking collars 1 1. In Figure 4 the wind power generator 14 is installed on top of upper ring element 1 and adapter 15 at the stage when the first ring element 1 has been lifted to the top level of the tower assembly device 4. The frame of the hybrid tower shown in Figure 5 consists of both the steel part and the concrete elements. The upper steel part and the generator 14 are installed at the stage when the vertical position of the concrete part of the tower is at the upper level of the assembly device 4. The generator 14, or the upper steel column and generator 14 can be installed subsequent to any lifting phase of the ring element 1. In Figure 6, the vanes 16 of the wind turbine generator 14 are installed directly from the bed of the transport vehicle at the stage when the tower assembly has progressed so far that the vertical position of the generator 14 corresponds to the dimension of the vane 16. The vanes 16 can also be installed at a later stage.

In the above example, a multifunctional carriage 6, which lifts and moves the ring elements 1 under the assembly device 4, has been described. Alternatively, it is possible to use the multifunctional carriage 17 shown in Figure 7, which carriage lifts and moves the ring elements 1 as well as climbs up along the frame of the assembly device 4. In Figure 7, the multifunctional carriage 17 is shown from the front in its upper and lower position. In the Figure 8 multifunctional carriage 17 is shown from the side in its upper and lower position. Multifunctional carriage 17 is provided with an U-shaped wagon, where the frame beam connected to the rear part of the frame is located above the foundations of the tower. The multifunctional carriage 17 is able to park underneath assembly table 5, raise the assemble ring element 1 together with assembly table 5 and transfer it across the tower foundations to below assembly device 4. The multifunctional carriage 17 is provided with a motor and wheels below the frame beam for transfer, and with hydraulic cylinders 19 for lifting the assembly table 5 and for climbing along the frame of assembly device 4. Climbing takes place by means of hydraulic cylinders 19, which have lever-type locking and unlocking mechanisms 18. When such a multifunctional carriage is used, 17 the lowest ring element 1 of the assembly ring of the assembly device 4 comprises two semi-circular structures, which are released from each another after the installation.

The vertical alignment of the tower is controlled for example with the help of spacers fitted between the ring elements, using a plumb wire suspended from the middle of the top of the tower or with a laser. In building the tower, more than one multifunctional carriage can also be used, for example when the installation paths 3 are on both sides of the tower foundations. In this case the multifunctional carriages install segments alternately from different sides of the tower.

Especially in high towers, prestressed steel wires are used. The prestressed steel wires needed to reinforce the tower can be preinstalled inside the top ring element and attached to the adapter at ground level already in the assembly phase, making them easy to straighten and prestress as the assembly of the tower proceeds. Installation and prestressing of the steel wires can be carried out in two stages, whereby for example the top of the tower is prestressed when the vertical position of the tower is at the level of the upper part of the assembly device 4, and the lower part of the tower is prestressed when the tower is ready. It is also possible to prestress only part of the tower or the whole tower in one part.

Using the wind turbine tower assembly method described in the invention, high towers can be built without big cranes, thereby saving time and costs. Furthermore, the above described assembly method is fast, because the segments are assembled in advance on the assembly tables with the help of the gantry cranes, transferred with the multifunctional carriage along the installation path under the assembly device and lifted into the place with the assembly device without the help of the cranes. The wind turbine adapter, the steel parts, the generator and the installation of the vanes are done at the early stage of assembly, when the tower is low and lifting is easy. When working on the ground level it is easier to take care of safety issues and weather changes, wind and winter conditions cause fewer problems. The ring elements are located on the compact area above the installation path, so they are easy to protect from rain for example using a collapsible tent, and to heat. The solution according to the invention is particularly suitable when sufficiently large cranes are not available or when it is not possible to transport big cranes to the assembly site, for example in mountain areas. Large cranes need supporting bases, the construction of which is not required according to the invention, since the tower foundations can be relied upon.

Claims

A method for assembling a wind turbine tower on an erection foundation, in which method at least two ring elements (1), as high as part of the tower, are composed from concrete segments (2) and the ring elements (1) are lifted into a superimposed position in the order of assembly, characterized in, that

the first ring element (1) is lifted in an upright position to the vertical position of the next ring element (1) and locked at that height,

the following ring elements (1) are placed individually in the assembly order below the previous ring element (1) and lifted with the previous ring element (1) or the ring elements the height of the next ring element (1) and locked at that height, the last ring element(l) is lifted into contact with the previous ring element and released connected together to a suspended state, and

the superimposed ring elements (1) are lowered onto the erection foundation.

A method according to claim 1, characterized in, that a generator (14) is installed subsequent to any lifting phase of the ring element (1).

A method according to claim 1 , characterized in, that an upper steel column and the generator (14) are installed subsequent to any lifting phase of a ring element (1).

A method according to any of the preceding claims, characterized in, that when the vertical position of the generator (14) corresponds to the dimension of a vane (16), the vanes (16) are installed.

A method according to any of the preceding claims, characterized in, that prestressed steel wires are installed inside the top ring element (1) and attached to an adapter.

A method according to any of the preceding claims, characterized in, that the

prestressed steel wires of the wind turbine tower are installed and prestressed in two stages.

7. A device for mounting a wind turbine tower on an erection foundation, characterized in, that the device comprises an installation path (3), an assembly table (5), a multifunctional carriage (6, 17) and an assembly device (4).

8. A device according to claim 7, characterized in, that the multifunctional carriage (6, 17) is provided with wheels and driving motors for the transfer of the ring elements (1) and hydraulic cylinders (19) for lifting the ring elements (1).

9. A device according to claim 8, characterized in, that the hydraulic cylinders (19) of the multifunctional carriage ( 17) enable climbing along the frame of the assembly device (4).

10. A device according to claim 9, characterized in, that the hydraulic cylinders (19) of the multifunctional carriage (17) have a lever-type locking and unlocking mechanisms (18).

1 1. A device according to claim 7, characterized in, that the assembly device (4) consists of frame guide columns (10), locking collars (1 1) for climbing along the guiding columns (10) and the upper locking ring (9) used for suspending the tower.