The present invention relates to a wind turbine tower, wind turbine tower installation apparatus and methods of erecting a wind turbine tower.
The invention relates to the technical field of wind turbines, and more specifically to the installation and construction of wind turbines.
For increased efficiency it is desirable to provide wind turbines with larger rotor areas (to increase the capacity of the turbine) and to position the turbine at a higher elevation (as wind speeds typically increase with altitude and wind is subject to less disruption). As such, there is a trend towards building wind turbines with towers having much greater length. Further, the growth of offshore wind turbines is an additional driving factor towards larger and taller wind turbines.
As wind turbines grow taller the installation process becomes more challenging such that there is a need for effective methods and apparatus for successful installation of tall wind turbines. Conventionally, the wind turbine tower is constructed of a series of longitudinally stackable tubular sections which must be placed and secured end on end. The assembly process therefore comprises first installing a base section of the tower (for example embedded on a platform or foundation) before installing the tower sections in sequence followed by a nacelle and blades on the final section. This installation is carried out using extremely large cranes, but the size of the cranes is such that significant work and infrastructure is required to merely position and install the cranes before work can commence on the wind turbine itself. For example delivery of the parts of a crane to an installation site may require some 80 semi-trailers. Furthermore, it may be very challenging, and require acceptable weather conditions, to install parts of the wind turbine, particularly the uppermost parts, when they are lifted by a crane separate from the tower, for example because of relative movement of the crane and the tower.
Accordingly, the applicant has proposed (in their co-pending Norwegian patent applications NO20201367, NO20201368, NO20201369 all having a filing date of 11 Dec. 2020) an apparatus and method for performing parts of an operation to install a tower for a wind turbine in which an apparatus comprising a travelling car for travelling up and down along an installed tower section of the wind turbine and for carrying an item to be installed as part of the wind turbine. This apparatus and method provides significant potential advantages over the conventional, crane based, methods of installation. Embodiments of the invention seek to provide further improvements and/or alternatives to the apparatus and method.
According to a first aspect of the invention, there is provided a wind turbine tower installation apparatus for installing a tower comprising a plurality of longitudinally stackable sections, wherein the apparatus comprises a frame comprising a guide for positioning the apparatus on an installed portion of a tower, a platform for supporting wind turbine components on the frame, and at least one transverse positioning mechanism for transversely positioning the supported wind turbine component in alignment with the tower; and a lifting mechanism for moving the apparatus longitudinally up and down the tower, wherein the apparatus is characterized by the at least one transverse positioning mechanism further comprising: an adaptor frame defining a collar for receiving and aligning the end faces of the free end of the installed portion of the tower and the adjacent end of the subsequent tower section.
The adaptor frame may further comprise an adjustment mechanism. The adjustment mechanism may be configured for correcting the cross-sectional shape of one or both of the end faces. For example, the adjustment mechanism may remove or reduce any non-conformity or irregularity in the cross-sectional shape of the end faces. The tower may typically be specified as having a circular profile but in practice when the tower is installed the profile is found to have some non-conformity for example it may have a degree of ovality to its profile (this may for example be a result of manufacturing tolerances or resultant of the handling or storage of the tower between manufacturing and installation). As such, the adjustment mechanism may be intended to return or adjust the end section of the tower into close tolerance with the intended circular form.
The adjustment mechanism may further comprise a locking mechanism for retaining the end of the tower section in the adaptor frame. In particular the adjustment mechanism may provide a locking mechanism to retain the free end of the uninstalled tower section in the adaptor frame. For example, this may allow the uninstalled tower section to be inserted into the adaptor frame and secured prior to moving the adaptor frame into position on the free end of the installed section (thus positioning the subsequent tower section). Adjustments to the profile of end of the uninstalled tower section may be performed prior to or subsequent to positioning on the installed tower section.
The adjustment mechanism may radially engage a periphery of the tower proximal to the end face. The adjustment mechanism may force the end section of the tower to deform into conformity with the profile of the adaptor frame. The periphery of the tower proximal to the end face may comprise a side wall of the tower section.
The adjustment mechanism comprise a plurality of circumferentially distributed engagement members. The engagement members may comprise a plurality of radial fingers. Each radial finger may project radially from the adaptor frame and have head to engage a surface of the end section of the tower.
In one example, each radial finger may project inwardly from the adaptor frame and have a head to engage an internal surface of the end section such that the fingers outwardly radially load the end section. In this arrangement the fingers may force the external surface of the end section into conformity with an internal alignment surface of the adaptor frame. The internal alignment surface of the adaptor frame may for example be an internal circumferential wall of the collar.
In another example, each radial finger may project inwardly from the adaptor frame and have a head to engage an external surface of the end section such that the fingers inwardly radially load the end section.
The end section of the tower section may include a feature, for example a circumferential rib or groove for seating the adaptor frame. For example, the rib or groove may provide a seat for the head of the radial fingers of the engagement members.
The apparatus of embodiments may also help enable novel methods of assembly. As such, a further aspect of the invention provides a method of erecting a wind turbine tower, the method comprising the steps of:
It may be appreciated that the order of the steps in the method is not considered limiting. In some embodiments the adaptor frame may be positioned around the subsequent tower section before being positioned around the free end of the installed tower section. The method may for example comprise the step of engaging and retaining the subsequent tower section in the adaptor frame and using the adaptor frame to move the tower section.
The method may comprise adjusting the end profile of at least one of the tower sections. Adjustment may be achieved by clamping the end in the adaptor frame. Adjustment may correct the shape of the end for example remove or reduce any non-conformity or irregularity in the cross-sectional shape of the end. The method may comprise adjusting the shape of both ends prior to aligning the tower sections. For example, the method may comprise adjusting the end profile of both tower sections prior to inter-engaging the tower sections.
Methods and apparatus in accordance with embodiments may enable greater alignment accuracy between tower sections particularly when any non-conformity in the end profiles is corrected. As such, methods and apparatus may enable a variety of interconnection arrangements between tower sections (in contrast to conventional methods where a simple bolted abutment joint between adjacent flanges may be necessary but require significant manual work). In some embodiments the method may, for example, comprise forming a lap joint between the tower sections. The method may comprise engaging a clamping ring between the ends of the tower segments after the sections are aligned.
Accordingly, in a further aspect of the invention, there is provided a wind turbine support tower comprising: a plurality of longitudinal tower sections, the tower sections being stacked end-to-end to form the tower, wherein each tower section comprises a hollow tubular member and a mating interface is provided at adjacent ends of respective tower sections, characterised by the mating interface comprising complimentary sleeve portions formed at the end of the tower section, the sleeve portions being configured to be coaxially adjacent when the tower sections are stacked end-to-end and wherein one of sleeve portions comprises a radially displaceable locking ring and the other of the sleeve portion comprises a radially extending feature for engaging the locking ring. The radially extending feature may for example be a recess or flange. The radially extending feature may engage or abut a radially adjacent surface of the locking ring.
The radially displaceable locking ring may comprise a plurality of radial bolts for positioning the locking ring. The locking ring may comprise a plurality of circumferential segments.
The mating interface may further comprise at least one radially extending flange for axially aligning the sleeve portions. The at least one radially extending flange may abut an end face of the tower section and may, for example be axially inward of the sleeve portion. Both sleeve portions may terminate at a radially extending flange.
The wind turbine support tower may further comprise an adaptor frame defining a collar for receiving and aligning the mating interface, provided at adjacent ends of respective tower sections, during assembly. In some embodiments the tower may comprise a specific adaptor frame for each section-to-section connection of the tower.
According to yet a further aspect of the invention, there is provided the adaptor frame of the wind turbine installation apparatus in accordance with the invention, the adaptor frame defining a collar for receiving and aligning end portions of the free end of the installed portion of the tower and the adjacent end of the subsequent tower section. The inventors discovered that the adaptor frame may actually be used without the wind turbine tower installation apparatus of the invention, for instance when the tower sections are lifted and placed on top of each other using a crane. In such scenario also the adaptor frame may be lifted and placed on the tower being built, facilitating the alignment of the tower section to be placed to the tower sections already placed.
Unless otherwise stated, each of the integers described may be used in combination with any other integer as would be understood by the person skilled in the art. Further, although all aspects of the invention preferably “comprise” the features described in relation to that aspect, it is specifically envisaged that they may “consist” or “consist essentially” of those features outlined in the claims. In addition, all terms, unless specifically defined herein, are intended to be given their commonly understood meaning in the art.
Whilst the invention has been described above, it extends to any inventive combination of the features set out above or in the following description or drawings.
Embodiments of the invention may be performed in various ways, and embodiments thereof will now be described by way of example only, reference being made to the accompanying drawings, in which:
Note that the embodiments shown in the figures are mere examples of the invention, and that they are not necessarily drawn to scale. Other embodiments being configured differently from those shown in the figures may be within the scope of the invention according to the claims.
As noted above, the applicant has proposed an apparatus and method for performing parts of an operation to install a tower for a wind turbine. This apparatus and method will be briefly described with reference to
As shown in
The travelling car 101 comprises a frame 110 defining a generally horizontal platform 102 (see
In
Subsequently, in
As can be further seen in
Once the final tower section is installed (in this case 223) the lifting mechanism is again attached to the upper end of the installed tower section, as shown in
As shown in
An installation apparatus 100 is shown in further detail in
As shown in the detail aspect of
Initially, the actuators 160 may be used as a locking mechanism to engage and retain the tower segment end 500 in position in the adapter frame 150 (although alternatively a separate locking mechanism may be provided). Once secured the actuators 160 act as an adjustment mechanism by applying a force onto the end section 500. Due to the distributed nature of the actuators 160 the force applied can be applied around the full periphery of the end wall 505 (see
An alternate configuration of the adaptor frame 150′ is shown in
As the apparatus according to embodiments enables non-conformity (such as ovality) to be removed from the tower end 500 or 400 prior to connection embodiments enable the use of a finer tolerance attachment between the tower sections. In contrast, conventional tower sections are typically connected by axial aligned bolts extending through abutting flanges at the interface between the sections. Such bolted connections typically require a significant amount of manual labour for connection.
A partial cross-section of the connection interface between tower sections 221 and 221 in accordance with embodiments is shown in
The lower end 500 of the upper wing section 222 is provided with a complementary interface arrangement formed by flange 520. The flange 520 extends from a first end proximal to the end face 525 (which in use abuts the seat 425 of the flange 410). The flange 520 forms a radially aligned locking surface 530 (which could optionally be part of a recess) which faces away from the open end of the tower section. A tapered ramp surface 540 is provided on the flange axially forward of the locking surface 530.
The end sections 400, 500 provide respective sleeve portions of the tower sections 221 and 222 which form a lap joint between the sections in use. When aligned and adjusted by the adaptor frame 150 of the installation apparatus 100, the end section 500 is able to pass over the flange 410 of the end section 400. As the sections 221 and 222 are brought axially together (by lowering the upper section 222) the ramp surface 530 and tapered wall 420 will slide across each other until the end face 525 abuts the seat 425 formed in the flange 410. In this position the locking ring 440 will have axially aligned beyond the locking surface 540 of the flange 520. The plurality of radial bolts 430 may then be fastened to secure the locking ring 440 in position behind the flange 520 with the radial locking surface 530 and radial face of the locking ring 440 ensuring that the engagement between the sleeve portions of the tower sections is secure.
As already mentioned in the introduction, the adaptor frames 150, 150′ as illustrated in
The method according to embodiments of the invention is shown schematically in
It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb “comprise” and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
Although the invention has been described above with reference to preferred embodiments, it will be appreciated that various changes or modification may be made without departing from the scope of the invention as defined in the appended claims. For example, whist the illustrated embodiment uses the adjustment mechanism to adjust the shape of the end of the subsequent tower section in some embodiments the mechanism may alternatively or additionally adjust the shape of the end of the installed tower section. Further, whilst the interface between tower sections in the illustrated embodiment is generally internal to the tower (having internal bolts and an outwardly projecting retaining ring) it will be appreciated that this arrangement could be reversed.
Number | Date | Country | Kind |
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20210880 | Jul 2021 | NO | national |
This application is the U.S. national stage application of International Application No. PCT/NO2022/050142, filed Jun. 22, 2022, which international application was published on Jan. 12, 2023 as WO 2023/282756 in the English language. The International Application claims priority to Norwegian patent application Ser. No. 20/210,880, filed Jul. 7, 2021. The international application and Norwegian application are both incorporated herein by reference, in their entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/NO2022/050142 | 6/22/2022 | WO |