Patent ID: 12188452

DETAILED DESCRIPTION

The illustrations in the drawings are schematically. It is noted that in different figures, similar or identical elements are provided with the same reference signs.

FIG.1shows a wind turbine1according to embodiments of the invention. The wind turbine1comprises a tower2axially extending along a longitudinal axis Z of the wind turbine1. In the following with the term “axial”, where not further specified, reference is intended to a direction parallel to the longitudinal axis Z. A nacelle3is attached to an upper end of the tower2. The wind turbine1further comprises a wind turbine rotor5having three blades4(in the perspective ofFIG.1only two blades4are visible). The rotor5is attached to the nacelle3in order to be rotatable around a rotational axis Y. The tower2comprises a plurality of axially adjacent tower segments (four tower segments7a.7b,7c,7din the embodiment ofFIG.1). Each tower segment7a,7b,7c,7dextends axially between two axial ends, where means for connecting the tower segments to each other are provided, as better detailed in the following.

The wind turbine1comprises a concentrated winding electrical generator10. The wind rotor5is rotationally coupled with the electrical generator10by means of a rotatable main shaft9. According to other possible embodiments of the present invention (not represented in the attached figures), the wind rotor5is rotationally coupled directly with the electrical generator10(direct-drive generator configuration). A schematically depicted bearing assembly8is provided in order to hold in place the rotor5. The rotatable main shaft9extends along the rotational axis Y. The permanent magnet electrical generator10includes a stator11and a rotor12. The rotor12is radially external to the stator11and is rotatable with respect to the stator11about the rotational axis Y.

FIG.2shows two tower segments7a,7bconnected together at two respective axial ends by means of a plurality of bolts22. The bolts22join together two respective flanges21provided at the respective axial ends of the tower segments7a,7b. The flanges21protrude from a cylindrical wall23of the respective tower segment7a,7baccording to a direction, which is orthogonally oriented with respect to the longitudinal axis Z. Similar connections may be provided between the tower segments7b,7cand between the tower segments7c,7d.

FIGS.3and4show more detailed views of the first tower segment7a. The other tower segments7b,7c,7dmay be identical to the first tower segment7aofFIG.3. One or both the axial ends of the first tower segment7ainclude a respective “T” flange21. The “T” flange21comprises a first portion21aprotruding inwards, i.e. towards the longitudinal axis Z, and a second portion21bprotruding outwards, i.e. opposite to the longitudinal axis Z. Holes for connecting the bolts22to the flange21are provided on both the first portion21aand the second portion21b. The first tower segment7acomprises a rail20attached to the second portion21bof the flange21. The rail20is a circular ring coaxial with the longitudinal axis Z and extending for 360° about the longitudinal axis Z. According to other embodiments of the present invention (not shown) the rail20extends for an angle smaller than 360° about the longitudinal axis Z. According to another embodiment of the present invention (not shown) a rail may be provided also along the first portion21aof the flange21. The rail20is attached to the respective flange21by means of a plurality of supports25regularly distributed about the longitudinal axis Z. The supports25are fixed, for example by welding, to both the flange21and the rail20.

The rail20provides a guide for attaching a service trolley30to the tower20. The service trolley30is attachable in order to be translated along the rail20. The service trolley30has a curved shape parallel to the guide20and extends for an angle smaller than 360° about the longitudinal axis Z. The coupling between the service trolley30and the rail20may be provided by means of a wheeled connection or any other sliding connection. The rail20may be provided at one or both the axial ends of each tower segment7a,7b,7c,7d.

FIGS.5and6show how the service trolley30and the rail20may be used for operating a service platform40along the external surface of the cylindrical wall23. A retaining cable55is arranged around the tower2in a belt configuration and attached to the service platform40. The retaining cable55reduces movements, in particular lateral movements, of the service platform and improves security and increase the wind speed limit to operate.

In an initial step of a method for mounting the tower2a first tower segment7aand a second tower segment7bidentical to each other are provided. The rail20is provided at least at a second axial end of the second tower segment7b, i.e. to the axial end of the each second tower segment7b, which in the assembled tower2is distanced from the first tower segment7a. In a following step of the method the service trolley30is attached on the rail20. In a further step of the method, the first tower segment7aand a second tower segment7bare axially attached to each other, the first axial end of the second tower segment7bbeing attached to the first tower segment7a. The first tower segment7aand the second tower segment7bare fixed to each other by means of a plurality of bolts22provided on the first portion21aof the respective flanges21. Other bolts22may be prefixed to the second portion21bof one of the flanges21at the interface between the first tower segment7aand the second tower segment7b. In a further step of the method, a service platform40is attached to the service trolley30. The service platform40may be attached to the service trolley30by means of a lifting apparatus including a plurality of cables41,42, which connect the service platform40may be attached to the service trolley30. The cable may be used to operate the service platform40in a direction parallel to the longitudinal axis Z. The position of the service platform40about the longitudinal axis Z can be varied by sliding the service trolley30along the rail20. In a further step of the method, the service platform40is used by operators for fixing the plurality of bolts22on the second portion21bof the flanges21at the interface between the first tower segment7aand the second tower segment7b. Bolts22of a further downstream flange between a tower segment and another tower segment are accessed.

FIG.7shows a further step of the method, wherein a parapet clamp50is used for removing the service trolley30from the second axial end of the second tower segment7b. In a further step of the method, the service trolley30may be attached to a third tower segment7cfor attaching the third tower segment7cto the second tower segment7bin an analogous way to that above described for the first tower segment7aand the second tower segment7b.

According to other embodiments of the present invention, the rail20may be used for performing other service and maintenance operations on the external surface of the tower2.

According to other embodiments of the present invention (not shown) the rail20may be provided at an intermediate axial position between the two axial ends of a tower segment7a,7b,7c,7d.

According to other embodiments of the present invention (not shown) the rail20may be provided on the external surface of a tower2for a wind turbine not having an axially segmented structure.

Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements.