A wind turbine tower, a wind turbine, a wind turbine tower elevator and a method for assembling a wind turbine tower

ES 2 394 460 T3

DESCRIPTION

A wind turbine tower, a wind turbine, an elevator for a wind turbine tower, and a procedure for assembling a wind turbine tower

Field of the invention

The invention relates to a wind turbine tower according to the preamble of claim 1, to a wind turbine and to a method for assembling a wind turbine tower.

Description of Related Art

A wind turbine tower known in the art comprises a frusto-conical wind turbine tower and a wind turbine nacelle located on top of the tower. A wind turbine rotor with three wind turbine blades is connected to the nacelle by a low speed shaft, which extends outward from the front of the nacelle, as illustrated in Figure 1.

Wind turbine towers typically comprise a number of round frusto-conical tower sections mounted one on top of the other. The tower sections are typically bolted together by internally horizontal flanges, which are welded to the top and bottom of each tower section. Each of the tower sections comprises a number of tower rings welded together. These tower rings are typically made of steel plates, which are rolled in a circular shape and welded to form a closed 360 ° ring.

The general idea behind this design is that the tower has to be relatively easy to mount at the mounting site and that a round tower without any visible joints is more pleasing to the eye. However, in recent years the development of mass produced wind turbines has evolved towards making them larger and larger, both in power and in size. This process demands better and more cost-efficient components and manufacturing procedures, and specifically in the field of wind turbine towers, this development has been profound. Large modern wind turbine tower installations require a building with a clear height of 8 m, access to lifting equipment with a capacity of 70 t and highly specialized and expensive rolling equipment. Furthermore, welding reduces the fatigue limit of the towers and therefore their strength, which makes it necessary to manufacture the tower, or at least parts of the tower, of thicker plates than would otherwise be necessary.

United States patent US 3,034,209 refers to a process for producing frusto-conical tubular sections from sheet metal material, which are fitted one inside the other by overlapping joints in order to form a tubular mast, and in which each section is made up of one or more sheets that are joined by a combination of welding and riveting.

European patent application EP 1 561 883 discloses a wind turbine tower made of staggered precast metal parts. The metal parts are formed as long, substantially rectangular plates, which are open on the inward facing side of the tower. The pieces are screwed together inside the tower through their adjoining sides. A large annular reinforcing ring may be arranged inside the tower to improve the rigidity of the towers. This design provides a polygonal tower in which welding in and between tower sections is eliminated or greatly reduced. However, metal parts are complex in design and therefore difficult and expensive to manufacture. A wind turbine having the features of the preamble of claim 1 is disclosed.

An object of the invention is to provide a wind turbine tower without the mentioned disadvantages.

Especially, it is an object of the invention to provide a cost efficient tower design which provides a simple tower manufacturing process.

Furthermore, it is an object of the invention to provide efficient means for assisting in tower mounting and subsequent maintenance.

The invention

The invention is defined by a wind turbine tower according to claim 1.

The invention provides a wind turbine tower comprising at least two annular tower rings positioned vertically one above the other. A first tower ring of said at least two tower rings overlaps with at least one additional tower ring of said at least two tower rings, wherein the at least two tower rings comprise at least two tower plates and in wherein the at least two tower plates comprise a first vertical or substantially vertical side section and a second vertical or substantially vertical side section, wherein the first section overlaps a second lateral section of a horizontally juxtaposed tower plate, and wherein the at least two tower plates are overlappingly connected by means of

ES 2 394 460 T3 bolts.

It is advantageous to have the tower rings of a wind turbine overlap, as this provides a simple tower design that can be manufactured by low-tech manufacturing means.

Making the tower rings overlap allows the possibility of connecting the rings by mechanical connecting means such as screws, bolts or rivets. Thus, welding in the tower is avoided, and especially in areas of the world where the labor hour is relatively cheap it is economically advantageous, for example, to screw the rings together, since although it may take more time to manufacture welded joints, the bolted tower can be made of a thinner plate, thus reducing the material cost of the tower.

It should be emphasized that in a wind turbine tower known in the art the tower rings are usually welded together in tower sections, which are then bolted together. In a wind turbine tower according to the invention all connections between the rings and tower sections are in principle the same. This means that when referring to a tower ring or rings, these could also be tower sections, since a tower section in a tower according to the invention would be a number of tower rings connected in the same way in the which sections would connect.

By fabricating the tower rings from a number of tower plates, it is possible to fabricate the plates in a manufacturing facility with a clearance less than the full diameter of the tower ring, and the plates are smaller and lighter than a tower ring. complete, and therefore easier to handle during manufacture. Furthermore, the design of traditional welded towers is limited by the fact that the tower sections or rings have to be able to pass under bridges, high voltage cables, etc. during transportation. By manufacturing the tower rings from a number of tower plates it is possible to transport the tower as individual plates which are mounted at or near the lifting site. Therefore it is possible to design towers with a better load transfer quality, such as a tower having, for example, more than 10 meters in diameter at the base of the tower.

Making the tower plates overlap laterally is advantageous as it allows the possibility of connecting the tower plates by means of bolts.

In one aspect of the invention, said at least two tower rings overlap in a substantially horizontal overlapping region consisting of a lower section of one tower ring and an upper section of other tower rings.

It is advantageous to have the tower rings overlap in an overlapping region as described, since an advantageous region is thus established for connecting the tower rings.

In one aspect of the invention, said substantially horizontal overlap region extends in said longitudinal direction of the tower rings.

Having the overlap region extend in the same direction that the tower rings extend is advantageous as it provides a simple tower design in which the tower rings are relatively simple to manufacture and the connection of the rings Tower can be made simply by means of, for example, bolts.

In one aspect of the invention, said lower section and / or said upper section is inclined at an angle α, β, respectively, relative to an intermediate section of said tower rings.

It is advantageous to bend the lower section and / or the upper section of an overlap, as this provides a more optimal load distribution along the overlap.

In one aspect of the invention, said angles α, β are between 0.5 ° and 15 °, preferably 1 ° and 10 °, and most preferably between 2 ° and 7 °.

If the angles are too small, the load distribution becomes less optimal and if the angles are too large the tower rings become more difficult to fabricate and the overlap region becomes less material efficient.

The present angle range thus provides an advantageous relationship between good load distribution and material usage.

It should be emphasized that the angles α and β do not necessarily have to be exactly the same.

In one aspect of the invention, said at least two tower rings overlap downward, causing an upper tower ring to overlap with a lower tower ring located immediately below said upper tower ring, and so on.

Having the tower rings overlap downwards is advantageous as the gap between the overlapped rings will be facing downwards, thus reducing or eliminating the risk of water penetrating the joint, as rain,

ES 2 394 460 T3 snow and others will run along the surface of the tower.

In one aspect of the invention, said at least two rings are connected by said substantially horizontal overlap region.

It is advantageous to connect the tower rings via the overlap region, as this provides an advantageous location for connecting the tower rings by mechanical connecting means such as bolts, screws or rivets.

In one aspect of the invention, said at least two tower rings are connected by bolts.

Connecting a load transport joint in a wind turbine tower by means of welding is a rather complex procedure, which has to be carried out properly by certified welders and possibly subsequently controlled by means of a control procedure such as X-rays, ultrasound, or other non-destructive control procedure to ensure the quality of the joint. The person who bolts a bolted load transport joint of a wind turbine tower needs only very little training to do the job satisfactorily, and the control procedure is much simpler and requires much simpler equipment.

Furthermore, the connection could also be made by screws or rivets, however screws are usually more expensive than bolts and the assembly of traditional rivets usually takes too much time.

In one aspect of the invention, said at least two tower rings are of substantially constant height.

Manufacturing the tower rings of a substantially constant height is advantageous as it provides a simple tower ring manufacturing procedure and a simple tower assembly procedure.

In one aspect of the invention, wherein said at least two tower rings are made of steel.

Making the tower rings from steel is advantageous as this is a proven, relatively cheap and strong material that is well suited for making wind turbine towers.

In one aspect of the invention, said at least two tower rings comprise between 1 and 50, preferably 3 and 30, and most preferably between 5 and 11, such as 8 horizontally juxtaposed tower plates.

Manufacturing and assembly costs increase with the number of tower plates in a tower ring, but if the number of plates is very small the plates become larger and therefore more difficult to handle, and therefore the advantages previously mentioned are reduced or disappear.

The present range of plate quantities thus provides an advantageous relationship between manufacturing and assembly costs and the ability to handle the plates reasonably easily.

In one aspect of the invention, said at least two tower plates comprise between 1 and 5, preferably 2 or 3 vertical or substantially vertical folds.

Manufacturing costs increase with the number of folds, but in relation to load distribution the optimal tower ring design is round, since, for example, the tower has to transfer the moment of wind loads from all directions .

The present fold number range thus provides an advantageous relationship between manufacturing cost and quality of charge transfer.

In one aspect of the invention, said at least two tower plates have a lower width that is wider than the width of the upper width.

Making the tower plates wider at the bottom than at the top is advantageous as it provides an easy way to make the tower wider at the bottom than at the top, providing an advantageous tower design throughout. which refers to load transfer.

In one aspect of the invention, said tower plates in a tower ring are substantially identical in shape.

Making all the tower plates of a specific tower ring identical is advantageous as this simplifies the manufacturing and assembly processes.

In one aspect of the invention, said at least two tower plates comprise a cutout in at least one corner.

Providing the tower plates with a cutout in at least one corner is advantageous as it allows the possibility of making the tower plates overlap both upwards and downwards and laterally.

ES 2 394 460 T3

In one aspect of the invention, said at least two tower plates have a longitudinal extension of between 1 and 50m, preferably between 3 and 30m, and most preferably between 7 and 15m.

The longer the plates, the more difficult they are to handle, and the shorter they are, the higher the manufacturing and assembly costs of a tower of a given height become.

The present length range thus provides an advantageous relationship between manufacturing and assembly costs and advantageous handling qualities.

For example, if each tower ring of an 80 m high wind turbine tower comprises eight tower plates and each of those tower plates is approximately 11 m long, the completely disassembled tower can be housed in three shipping containers. 40 feet (12.2 meters).

In one aspect of the invention, said at least two tower rings are frusto-conical, which makes them wider in the lower section than in the upper section.

Making the tower rings wider at the bottom than at the top is advantageous as it provides an advantageous tower design in relation to load transfer.

In one aspect of the invention, said at least two tower rings are polygonal in shape.

In manufacturing the polygon tower, expensive and complex rolling equipment is avoided, as the rings can be formed by a number of vertical or substantially vertical pleats. Therefore the shape of the tower rings is not restricted to plants comprising highly specialized rolling mills, but the rings can be manufactured on much simpler and more common bending machines located anywhere in the world. This allows the towers to be manufactured close to their mounting location, even though these areas are often remote, and therefore transporting the towers over long distances is avoided.

Still further, the invention provides a wind turbine tower elevator for use in a wind turbine tower, characterized in that said elevator comprises means for allowing movement of said elevator both vertically and horizontally.

Providing a wind turbine tower with a wind turbine tower elevator comprising means for causing said elevator to move both vertically and horizontally is advantageous as it allows easy access to substantially the entire interior surface of the tower. Therefore, access to section joints and others is facilitated both during erection of the tower and during subsequent maintenance.

In one aspect of the invention, said elevator comprises means for causing an elevator basket of said elevator to maintain a constant distance from the inner surface of said wind turbine tower.

If the tower is flared, making it wider at the bottom than at the top, it is advantageous for the elevator to maintain a substantially constant distance from the inner surface of the tower rings, so that a person operating the elevator is capable of reaching all or almost all of the bolts during checking or tightening.

In one aspect of the invention, said means comprise a number of rails attached to the interior of said tower by means of magnets.

It is advantageous to provide the inner surface of the tower with a number of rails, as these provide a simple way of maintaining a substantially constant distance between the elevator and the inner surface of the tower rings. Furthermore, it is advantageous to join these rails by means of magnets, as this provides an easy way to join the rails and at the same time avoid welding.

In one aspect of the invention, said means that allow horizontal movement of said elevator comprise a substantially horizontal annular rail.

Using an annular rail to allow the elevator to move in the horizontal plane is advantageous as it provides a simple and proven way to move loads in a horizontal plane.

A tower according to the invention comprises, for example, a multitude of bolted joints. Providing the tower with an elevator according to the invention is advantageous since it is thus easy to access the joints connecting the tower rings and / or the tower plates. Both during tower assembly, immediately thereafter and at certain intervals during the life of the towers, the joint bolts have to be checked and possibly tightened. Therefore, an elevator is advantageous that can be easily positioned in front of or near the bolts regardless of their radial or axial position in the tower.

The invention also provides a method for assembling a wind turbine tower. Said method comprises the steps of establishing at least two tower rings each of which comprises at least two tower plates and wherein said at least two tower plates comprise a first vertical lateral section or

ES 2 394 460 T3 substantially vertical and a second vertical or substantially vertical lateral section, in which said first lateral section overlaps with a second lateral section of a horizontally juxtaposed tower plate, and in which said at least two tower plates are connected by said overlap by means of bolts, mounting a first tower ring of said at least two tower rings over at least one additional tower ring of said at least two tower rings, causing said first tower ring to overlap said additional tower ring, and connecting said first tower ring and said additional tower ring through its overlap by using connecting means, such as screws, bolts or rivets.

Thus, according to the invention, an advantageous method of assembling a wind turbine tower is achieved.

In one aspect of the invention, said connecting means are tightened by using an elevator comprising means for allowing the elevator to move both vertically and horizontally.

The threaded joints of a wind turbine tower have to be tightened several times during the life of the tower due to vibrations, variations in temperature and load etc., and doing this using an elevator, which can be moved both vertically and horizontally, is advantageous. as it provides easy access to the bolts.

In one aspect of the invention, an elevator basket of said elevator maintains a substantially constant distance from the inner surface of said tower rings.

In one aspect of the invention, said mounting is carried out at, or in the vicinity of, the mounting location where said wind turbine tower is to be erected.

Mounting the tower at, or in the vicinity of, the location where the tower is to be erected is advantageous as long-distance transportation of large tower parts that are difficult to handle is avoided. Furthermore, mounting the tower at, or in the vicinity of, the lifting site is possible due to the fact that a load bearing bolted joint can be manufactured correctly, even under relatively primitive conditions, in which a welded joint with cargo transportation requires a more controlled environment to be performed reliably.

Figures (edit)

The invention will be described in the following with reference to the figures, in which:

fig. 1 illustrates a large modern wind turbine known in the art, viewed from the front, fig. 2 illustrates a section of a wind turbine tower according to the invention immediately before the assembly of two round tower rings, seen in perspective, fig. 3 illustrates an embodiment of a round tower ring, seen from above, fig. 4 illustrates an embodiment of a polygonal tower ring, seen from above, fig. 5 illustrates a section of a wind turbine tower according to the invention immediately before the assembly of two polygonal tower rings, seen in perspective, fig. 6 illustrates a section of a wind turbine tower according to the invention during the assembly of two polygonal tower rings, seen in perspective, fig. 7 illustrates a part of a cross section of a tower section gasket known in the art, fig. 8 illustrates a part of a cross section of an embodiment of a tower ring gasket according to the invention, fig. 9 illustrates a part of a cross section of another embodiment of a tower ring joint according to the invention fig. 10 illustrates an embodiment of a tower plate before it has been bent, fig. 11 illustrates the same embodiment of a tower plate as illustrated in FIG. 10 after being bent, fig. 12 illustrates a cross section of a wind turbine tower according to the invention comprising an embodiment of an elevator, seen from the side, and fig. 13 illustrates a cross section of a wind turbine tower according to the invention comprising an embodiment of an elevator, viewed from below.

ES 2 394 460 T3

Detailed description

Fig. 1 illustrates a wind turbine 1 known in the art, comprising a frusto-conical tower 2, which is subdivided into a number of tower sections 6. A nacelle 3 of the wind turbine is located on top of tower 2.

The rotor 4 of the wind turbine, comprising a number of blades 5 of the wind turbine, is connected to the nacelle 3 by a low speed shaft extending outward from the front of the nacelle 3.

Fig. 2 illustrates a section of a wind turbine tower 2 according to the invention immediately before the assembly of two round tower rings 14, viewed in perspective. Fig. 2 shows an upper tower ring 8 being positioned on a lower tower ring 9, which causes the lower section 11 of the upper ring 8 to overlap the upper section 12 of the lower ring 9 in a horizontal overlapping region 35 . When the tower rings 8, 9 are in place, the two rings are joined by screwing or riveting the rings 8, 9 together through the rows of screw holes 10.

In this embodiment of the invention, the tower rings 8, 9 are manufactured as full 360 ° annular round rings. To make one ring overlap another ring, the diameter of the lower section 11 of the upper tower ring 8 has to be approximately, or at least two plate thicknesses, greater or less than the diameter of the upper section 12 of the tower ring. lower tower 9. This could be done by making the rings 8, 9 flare over their entire vertical extent, in parts of their vertical extent, or the lower and / or upper sections 11, 12 could be provided with a number of bending cutouts, which allow that the sections 11, 12 could overlap where they bend, even though their diameters were the same before they were bent.

Fig. 3 illustrates a round annular tower ring 14 viewed from above. In this embodiment of the invention, tower ring 14 is made of eight tower plates 13, but in another embodiment of the invention, tower ring 13 could comprise fewer or more tower plates 13, such as six, seven, nine or ten.

In this embodiment of the invention, the tower ring 14 has a constant uniform cross section in its longitudinal direction, which makes the tower ring 14 substantially cylindrical, although in a preferred embodiment of the invention the plates of tower could be wider at the bottom than at the top, making the tower ring 14 frusto-conical or substantially conical.

In this embodiment of the invention, a first lateral section 17 of a tower plate 13 overlaps with a second lateral section 18 of a horizontally contiguous tower plate 13. The first side section 17 of said adjoining tower plate 13 then overlaps with a second side section 18 of a further tower plate 13, and so on. This pattern continues all the time with a constant width (Wj) of the vertical joints, which unifies the design of the tower, although in another embodiment of the invention one plate 13 out of two could overlap with its horizontally neighboring plates 13 on Both Sides.

Fig. 4 illustrates a polygonal annular tower ring 14, viewed from above.

In this embodiment of the invention, all the tower plates 13 are substantially identical, and each tower plate 13 comprises two vertical or substantially vertical folds 16, which make the tower ring 14 polygonal, with twenty-four faces in this case , although in another embodiment the plates 13 could comprise another number of folds 16 such as three or four, making the ring 14 out of thirty-two or forty faces, if tower ring 14 comprises eight tower plates 13.

In still a further embodiment, the tower plates 13 of the tower ring 14 could be welded together, or the tower ring could be made of a tower plate 13 comprising a plurality of pleats 16, which were screwed or they were welded to join their two ends.

Fig. 5 illustrates a section of a polygonal wind turbine tower 2 according to the invention immediately before the assembly of two tower rings 14, viewed in perspective. Fig. 3 shows an upper tower ring 8 being positioned on a lower tower ring 9, causing the lower section 11 of the upper ring 8 to overlap the upper section 12 of the lower ring 9 in a horizontal overlap region. At this point in the mounting procedure, the tower plates 13 on the two tower rings 14 would be screwed together at their vertical joints 15, although in fig. 3 the vertical joints 15 are illustrated without connecting means such as screws, bolts or rivets.

Fig. 5 further illustrates that in order to overlap the upper and lower tower rings 8, 9, at least one corner of the plates 13 has to be removed. In this embodiment of the invention, three corners of each plate 13 are chamfered. A first upper corner 19 of a plate 13 on the lower tower ring 9 and a first lower corner 20 of a plate 13 on the upper tower ring 8 are chamfered to enable the plates 13 to overlap both vertically and horizontally. The second upper corner 21 is also chamfered in this embodiment of the invention to ensure free access to the screw holes, otherwise covered. In another embodiment, a second lower corner could be chamfered

ES 2 394 460 T3 also to ensure free access to the screw holes.

In another embodiment of the invention, only one corner of each plate 13 is chamfered or the corner or corners could comprise a cutout of another shape such as rectangular, polygonal or some other regular or irregular shape.

Fig. 6 illustrates a section of a wind turbine tower 2 according to the invention during the assembly of two polygonal tower rings 14, viewed in perspective. In this embodiment, only some of the screw holes are provided with connection means, which in this case are bolts 24 fitted with nuts on the inner side of the tower 2, although when the assembly process is finished, all the holes bolt shall be provided with means of connection.

In this embodiment of the invention, the chamfering of the first lower corner 20 of a plate 13 is visible, but in a preferred embodiment of the invention, the cutout that houses space for the corners of the overlapping plates 13 could be completely covered by an overlapping plate 13.

Fig. 7 illustrates a part of a cross section of a tower section joint 6 known in the art. As illustrated in fig. 1, a traditional wind turbine tower 2 comprises a number of rounded frusto-conical tower sections 6 mounted one above the other. The tower sections 6 are screwed together by internally horizontal flanges 7, which are welded to the top and bottom of each section 6.

Fig. 8 illustrates a part of a cross section of an embodiment of a tower ring gasket 14 according to the invention.

If a wind turbine tower 2 comprises tower rings 14 according to the invention, at least all or substantially all horizontal overlap regions 35 between tower rings 14 are connected by mechanical connection means such as screws, bolts, rods or rivets. Since the tower rings 14 are connected in this way along, or substantially along, the length of the tower 2, there is no difference between a tower section joint 6 and a tower ring joint 14 in a wind turbine tower 2 according to the invention.

In this embodiment, a lower section 11 of the upper tower ring 8 overlaps with an upper section 12 of the lower tower ring 9. The two rings are then joined together by means of bolts, screws, rods or rivets through of the four rows of screw holes 10. In another embodiment of the invention, the overlap region 35 could comprise another number of bolt rows such as one, two, three, five or six, and in another embodiment, the lower tower ring 9 could overlap with the upper tower ring 8.

Fig. 9 illustrates a part of a cross section of another embodiment of a tower ring gasket according to the invention. This is in principle the same type of tower ring gasket design illustrated in FIG. 8. The tower rings 8, 9 are usually frustoconical, which makes the tower 2 wider at the bottom than at the top. In this embodiment, the lower section 11 of the upper tower ring 8 is bent at an angle α, and the upper section 12 of the lower tower ring 9 is bent at an angle β, making the lower and upper sections 11, 12 flare at an angle other than intermediate section 31 of tower ring 14. The two bending angles α, β could be the same, such as 5 °, but in another embodiment of the invention, the bending angle α could be slightly greater (for example 2 °) than the bending angle β, making that the upper section 12 of the lower tower ring 9 presses out against the lower section 11 of the upper tower ring 8, when the rows of screw holes 10 are aligned.

In this embodiment of a horizontal overlap region 35, not all the load of the tower rings 14, nacelle 3, etc. located above the joint is carried by the connecting means. The interior of the lower section 11 of the upper tower ring 8 presses down on the exterior of the upper section 12 of the lower tower ring 9, thus providing a more optimal load distribution along the joint.

Fig. 10 illustrates embodiment of a tower plate 13 before it has been bent. If tower ring 14 is made of tower plates 13 comprising lower and upper sections 11, 12 at an angle, lower and upper sections 11, 12 could comprise bending cutouts 32 to allow plate 13 to be bent both horizontally as vertically. Fig. 10 illustrates that the tower plate 13 is provided with four vertical fold cutouts 32 before the lower and upper sections 11, 12 are bent along the horizontal fold 33.

Fig. 11 illustrates the same embodiment of a tower plate 13 as illustrated in FIG. 10 once it has been folded. Due to the bending cutouts 32, the plate 13 can be provided with vertical folds 16 once the lower and upper sections 11, 12 have been bent, without deforming the lower and upper sections 11,

12.

Fig. 11 further illustrates that the plate 13 has a lower width Wb that is wider than the width of the upper width Wt. A tower ring 14 made of tower plates 13, which are wider at the bottom

ES 2 394 460 T3 than in the upper part, it will also be wider in the lower part than in the upper part, assuming that the vertical joints 15 are of constant width Wj, as they are in a tower according to the invention. Thus, the tower rings 14 flare.

The tower plates 13 can be manufactured to a length Lp, which makes them easy to transport, for example in ISO standard 40 feet (12.2 meters) containers.

Fig. 12 illustrates a cross section of a wind turbine tower 2 according to the invention, comprising an embodiment of an elevator 22, seen from the side. In order to maintain the bolted joints, the tower is provided, in this embodiment of the invention, with an elevator 22. The elevator 22 comprises an elevator basket 23, which could also be a cage, a platform or others. The elevator basket 23 is connected to a lifting equipment 24 by one or more cables 29 to make the elevator basket 23 go up and down.

In this embodiment of the invention, the lifting equipment 24 is mounted on a horizontal rail 25, annular or substantially annular, in the upper part of the tower or in the vicinity of it. In this embodiment, annular rail 25 is mounted on a vibration damper 26 at the top of the tower, although in another embodiment rail 25 could otherwise be directly or indirectly attached to tower 2, to nacelle 3, to the yaw mechanism (not shown) or others. The annular rail 25 allows the starting point of the elevator baskets 23 at the top of the tower 2 to move, thus allowing the basket 23 to be raised and lowered along the entire interior of the tower 2.

In this embodiment, tower 2 is frusto-conical, offering a circumference that passes through all folds 16 in the upper part of tower 2 with a diameter of approximately 2.5 m and 4.5 m in the lower part. of the tower. As elevator 22 is primarily used to tighten bolted joints during tower assembly and throughout the life of the tower, it is essential that these joints can be accessible throughout the entire interior of tower 2. In this embodiment, the tower 2 is therefore provided with a number of vertical or substantially vertical guides 27, which in this case are a vertical rail 27 connected to the interior of the tower 2. For example, if 60 ° of the 360 ° of the tower rings 14 can be accessible from a given horizontal position, the tower 2 should be provided, for example, with six vertical rails 27 or six pairs or parallel vertical rails 27. To avoid welding them to the tower 2, the rails 27 could be connected to the tower by using bolts, screws, rivets, or as illustrated by using magnets 28.

When the basket 23 is in its upper position, it can move freely horizontally on the ring rail

25. The basket 23 is then connected to a vertical rail 27 or pair of rails by guiding means 30, and when the basket 26 is lowered it will maintain a constant distance from the inside of the tower rings 14, even though the horizontal cross section of the tower rings 14 rise downward.

In another embodiment of the invention, the vertical or substantially vertical guides 27 could be very taut cables connected to the upper and lower part of the tower 2, or other suitable means to keep the elevator basket 23 at a constant horizontal distance. or substantially constant with respect to the inner surface of tower 2.

Fig. 13 illustrates a cross section of a wind turbine tower according to the invention, comprising an embodiment of an elevator, seen from below. In this embodiment of the invention, the tower is provided with six vertical rails 27 that extend substantially from the bottom to the top of the tower 2. The horizontal annular rail 25 is closed, making it describe a complete circle of 360 °, but in another embodiment of the invention the annular rail 25 could be less than a complete circle, such as between 250 ° and 330 ° of a circle. complete, leaving room for example for me to pass a ladder (not shown), which could extend substantially along the entire vertical length of tower 2.

The invention has been exemplified above with reference to specific examples of overlapping tower rings 14, tower plates 13, and internal elevators 22 for use in a wind turbine 1. However, it should be understood that the invention is not limited to the examples. particular described above, but can be designed and altered into a multitude of varieties within the scope of the invention, as specified in the claims.

List

1. wind turbine

2. tower

3. gondola

Four. rotor

5. shovel

ES 2 394 460 T3

6. tower section

7. horizontal flange

8. top tower ring

9. lower tower ring

10. row of screw holes

eleven. lower section of a tower ring

12. upper section of a tower ring

13. tower plate

14. tower ring

fifteen. vertical joint

16. fold

17. first side section of tower plate

18. second side section of tower plate

19. first top corner of tower plate

twenty. first bottom corner of tower plate

twenty-one. second upper corner of tower plate

22. lift

2. 3. elevator basket

24. lifting equipment

25. horizontal ring rail

26. vibration damper

27. vertical guide

28. magnet

29. cable

30. guidance means

31. middle section of tower ring

32. bending cutout

33. horizontal fold

3. 4. cap screw

35. overlap horizontal region

Lp length of the tower plate α bending angle of the lower section β bending angle of the upper section

Wb bottom width of tower plate

Wt top width of tower plate Wj width of vertical joints