Field of the Invention

The present invention relates generally to the field of wind turbines, and, more partic- ularly, to a hub system for a wind turbine comprising a nacelle having a main structure, a rotor for rotation about a rotation axis, which rotor comprises at least two rotor blades and a hub provided with first connection means for connection of the rotor blades to the hub, which hub is a part of the hub system, which hub has a first part directed against the wind when in use, and a second part directed against the nacelle and provided with second connection means arranged for being connected with a main bearing supporting the rotor, wherein a spinner is attached on the hub via a number of brackets for covering at least the first part of the hub,

and wherein said spinner is symmetrically placed with respect to a rotation axis for the rotor.

Background of the Invention

US 2015/0023794 disclose a hub system of the type mentioned by way of introduction. This document does not disclose an air inlet into the hub or into the spinner. US 2006/0120862 Al disclose equipment for aeration of a rotor hub which is covered with a spinner. The aeration equipment is provided with a cup shaped cover for preventing intrusion of water into the hub. The cover is arranged in front of an opening in the spinner and is attached to the hub via a connection piece passing through the opening in the spinner. This document does not disclose that a water separator can mount- ed in the spinner.

There exists a need for providing a hub system, also called spinner system, which creates a visually smooth shape of the hub and transition to the nacelle. And it shall prevent water, snow and birds from entering the hub and nacelle.

Furthermore, there exists a need for providing more simple structures due to need of cost cutting. In general, the mounting and dismounting of a hub involves lifting of heavy weights, and there is a need to reduce the weight. For transportation there is a need to reduce the size.

Object of the Invention

It is the object of the present invention to obtain a hub system which fulfills the above mentioned desires and which overcomes the drawback explained above.

Description of the Invention

This object is obtained with a hub system being peculiar in:

that said spinner in a top part of the spinner comprises an air inlet provided with a tubular extension in which a water separator is arranged integrally with the spinner, and

that said hub part comprises a manhole covered with a hatch and arranged in the second part.

As the spinner and the water separator is manufactured integrally is shall be easy to mount and dismount the spinner and the associated water separator in order for maintenance work on the water separator. The water separator is built-in into the tubular extension in such way that the water separator will fit snugly in the tubular extension. Accordingly the water separator cannot be mounted or dismounted through the hole for maintenance. The unit formed by the spinner and the water separator is easily mounted and dismounted from the hub due to the use of brackets. The brackets may be bolted to the hub or be mounted with any other connections means for easy mounting and dismounting.

The spinner will be arranged in close relation to the hub in order not to be for bulky and will not allow for persons to enter between the spinner and the hub to do maintenance work.

The spinner may have a parabolic or semi-spherical outer shape. The spinner may be a nose cone of the hub. Use of nose cone, also called mini spinner, reduces weight and work and reduces installation costs. There is no need for work shop assembly. The spinner may be assembled with the hub on site. The spinner is easy to transport.

As the top part of the spinner comprises an air inlet, it allows cooling air to enter the hub. The water separator arranged in the air inlet will keep rain water out of the hub.

With top part is meant the part of the spinner pointing against the wind in direction away from the nacelle. The air inlet is provided in the form of an air duct being a tubular extension of the hole in the top part of the spinner. The air duct is shaped in such a way that the water separator ensures that rain water will be collected and will run out of the nose cone, due to gravitation, without entering the hub. The air inlet shall have a grid in the front which ensures that birds cannot enter the hub. On the other hand the grid must not block the airflow by trapped leaves and catkin.

The spinner shall have lifting points to allow mounting of the spinner when the hub is in an upright position.

Due to the water separator in the air inlet, it is not possible to provide a manhole in the nose of the hub. Accordingly, the manhole is provided in the second part of the hub. Hereby access is provided close to the nacelle. Hereby it is easy to have access almost directly from the roof of the nacelle.

The manhole hatch shall allow easy access through the man hole pointing upwards (0°) for service work. In case only one manhole is provided, the hub may be rotated so that the manhole points downwards. In this position it may be used as an emergency exit using an emergency decent devise. Furthermore, heavy components, such as pitch gear, can be lowered to the ground and up again though the manhole pointing downwards.

The hub may be provided with more than one manhole. It shall be possible to open the hatch with a handle both from the inside and the outside.

The hatch keeps rain water out and it prevents the cooling air from escaping out through the manhole.

The spinner gives smooth curve of the original design of the hub.

Together with the surrounding surface of the hub, the hatch shall form a flush surface in order to establish a smooth curved surface. This is an advantage for the aerodynamic properties and also decreases the risk that impurities are agglomerated.

A hatch opening inwards means better security. Therefore, for safety reasons, the hatch can only open inwards. This means that a person can step on it by mistake with- out any risk of falling out. Still, the hatch must have no-step stickers both on the inside and the outside.

In short, we have better DFX comparisons with a hub system, according to the present invention.

DFX comparison: Transportation/Manufacturing/Service/EHS/LMT Risk

2. Needs site work to nosecone

put on nosecone

Needs work shop assembly No need for work shop assem-

Assembly bly, saves man hour each set.

1. Better work space, 3. Inside hub work, still tough in spinno need for outner side work

Service

2. Massive check 4. Few brackets, points with spinfewer check ner brackets points

1 Fast rescue 3 Fast rescue

2. Need work in nar- 4. SUHMJ tor

EHS

row space work in narrow space

1. Massive brackets, 3. Fewer brackets, more failure posless failure possi¬

LMT risk sibility bility

2. Longer service 4. Shorter service time time

According to a further embodiment, the system, according to the present invention, is peculiar in that said spinner is provided with shirt parts extending to a position between the first connection means, thereby arranged for covering the first part of the hub and at least a part of the hub arranged between the first connection means. Such spinner is also called a mini spinner.

The shirt parts will cover the first part of the hub and the areas of the hub provided between the rotor blades. The second part of the hub is not covered with such spinner and the shirt parts will not cover the first connection means. According to a further embodiment, the system, according to the present invention, is peculiar in that the hub system also comprises separate cover parts for the first connection means when a mini spinner is provided. Typically, the first connection means may be a pitch bearing for the rotor blade.

It is possible with a mini spinner to cover the pitch bearing with the separate shirt parts. The separate shirt parts may be provided in segments e.g. four segments. This makes it easier to assemble. The pitch bearing cover shall be attached directly on the pitch bearing.

According to a further embodiment, the system, according to the present invention, is peculiar in that the hub system also comprises separate cover parts for the second connection means. Such cover part will be a hub-nacelle transition disc.

The disc shall form a rotating water tight closure of the nacelle front towards the hub. The disc shall have an overlap with the nacelle cover. There must be sufficient clearance between the parts to avoid interference when the hub is rotating, even when extreme deformation of MSTR, main bearing and hub is taken into account.

The weight of the parts of the mini spinner is approximately 1/3 of a traditional full cover and the heaviest individual part weighs 120 kg.

Furthermore, the system has a relatively small area which can carry snow, compared to a traditional full spinner. This reduces the fatigue loads on brackets and bolts significantly and the risk of broken brackets and bolts is very small.

The spinner system has sufficient strength for extreme loads. According to a further embodiment, the system, according to the present invention, is peculiar in that the hub said spinner is provided with shirt parts extending between the first connection means and extending to the second connection means thereby arranged for covering the first part of the hub and a part of the hub arranged between the first connection means and the second part of the hub. Such spinner is also called a full spinner.

According to a further embodiment, the system, according to the present invention, is peculiar in that said shirt parts in the full spinner comprise shirt parts covering the first connection means. Typically, the first connection means may be a pitch bearing for the rotor blade.

According to a further embodiment, the system, according to the present invention, is peculiar in that said air inlet is arranged in a hole being recessed from the top part of the spinner. Hereby, rounded edges for the hole may be provided. This increases the strength of the spinner.

According to a further embodiment, the system, according to the present invention, is peculiar in that the spinner has a parabolical or semi-spherical outer shape at the top part. These shapes are preferred, however, other shapes may also be used.

According to a further embodiment, the system, according to the present invention, is peculiar in that for a rotor comprising three rotor blades, there are provided three manholes as they are arranged in positions between the rotor blades.

The manhole pointing upwards (0°) will allow easy access through the manhole for service work while the two manholes pointing downwards can be used as an emergency exit, using an emergency decent devise. Furthermore, heavy components such as pitch gear can be lowered to the ground and up again though the two manholes positioned at 120° and 240° from a vertical position.

According to a further embodiment, the system according to the present invention is peculiar in that said hatch which covers the manhole is provided with a handle on the inside and the outside extending through the hatch. Hereby it is possible to open the hatch with a handle both from inside and outside.

According to a further embodiment, the system, according to the present invention, is peculiar in that said hatch is connected via a hinge with main hub through a hinge be- ing connected for inwardly opening of the hatch. As already mentioned, this is a security measure as a person can step on it by mistake without any risk of falling out.

According to a further embodiment, the system, according to the present invention, is peculiar in that said manhole is oval. Oval manholes adapt to the human body and oval manholes will give a smaller opening and a stronger structure.

According to a further embodiment, the system, according to the present invention, is peculiar in that said hatch is provided with a flange arranged to bear against an inner circular surface encircling the manhole. This gives further security in case a person by mistake steps on the hatch.

According to a further embodiment, the system, according to the present invention, is peculiar in that said hatch has a plane outer surface and is provided with a handle ex- tending to the above said outer surface of the hatch. Hereby, a flush surface is obtained and there is no risk that water agglomerates in a countersunk area.

According to a further embodiment, the system, according to the present invention, is peculiar in that said plane outer surface of the hatch is flush with the surrounding outer surface to form a closed surface seen from the outside of the hub. Hereby, a smooth profile curve is obtained.

Description of the Drawing

An embodiment of the invention will now be described by way of example only and with reference to the accompanying drawings, in which:

Fig. 1 shows a perspective view of a wind turbine,

Fig. 2 shows a partial view of a hub system comprising a full spinner,

Fig. 3 shows a partial view corresponding to fig. 2; however, with a hub system comprising a mini spinner,

Fig. 4 shows a perspective view of the mini spinner illustrated in Fig. 3 comprising an air inlet in the top part,

Fig. 5 shows a partial view of a manhole covered with a hatch, Fig. 6 shows a cross-section through a manhole covered with a hatch being partially opened,

Fig. 7 shows a partial view of a manhole covered with a hatch according to a further embodiment,

Fig. 8 shows a section through a mini spinner illustrated in fig. 4, and,

Fig. 9 shows a cross-section through a hub.

Detailed Description of the Invention

In the following text, the figures will be described one by one, and the different parts and positions seen in the figures will be numbered with the same numbers in the different figures. Not all parts and positions indicated in a specific figure will necessarily be discussed together with that figure.

Position number list

1 Wind turbine

2 Wind turbine tower

3 Foundation

4 Nacelle

5 Rotor hub

6 Wind turbine rotor blade

7 First end of blade (root end)

8 Second end of blade (tip end)

9 Full spinner

10 Mini spinner

11 Air inlet

12 Top part

13 Rotation axis

14 Manhole

15 Hatch

16 First part

17 Second part

18 First connection means

19 Second connection means

20 Opening 21,22 Brackets

23,24 Connection means

25 Hole

26 Outermost portion

27 Tubular extension

28 Shirt parts

29 Separate cover parts

30 Portion of full spinner

31 Separate cover parts

32 Surface of hatch

33 Surface surrounding manhole

34 Groove

35 Hinge

36 Handle

37 Countersunk hole

38 Flange part

39 Inner surface

40 Water separator

41 Annular ridge

Detailed Description of the Invention

In fig. 1 a typical wind turbine 1 is seen comprising a tower 2 installed at a foundation 3. At the top of the tower 2, a nacelle 4 comprising e.g. a gearbox, a generator and other components is seen. At the nacelle 4, a shaft for carrying a rotor comprising a hub 5 and three wind turbine rotor blades 6 is also installed. The rotor blades 6 are arranged at the hub 5 at a first end 7, called the root end of the rotor blade 6. The second end 8 of the rotor blades 6 constitutes a tip end.

Fig. 2 shows a spinner 9 which in a first embodiment is a full spinner.

Fig. 3 shows a spinner 10 according to a second embodiment which is a mini spinner. The spinner 9, 10 is provided with an air inlet 11 in a top part 12 of the spinner. In the air inlet 11 a water separator (not illustrated) is arranged. The spinner 9, 10 is placed symmetrically with respect to a rotation axis 13 for the rotor hub 5.

In figs. 1 and 2 a manhole 14 covered with a hatch 15 is illustrated. The surface of the hatch will be flush with the surface of the spinner, respectively, with the surface of the hub surrounding the manhole.

Fig. 9 illustrates a hub 5. The hub is a part of the hub system, according to the invention. The hub has a first part 16 which is directed against the wind when in use and a second part 17 which is directed against the nacelle.

The hub 5 is provided with first connection means 18 for connecting the rotor blades 6 to the hub 5. The first connection means is typically a bolt connection through which the rotor blades are mounted to a pitch bearing.

Furthermore, the hub is provided with second connections means 19 in the second part 17 of the hub. The second connections means 19 is typically a flange used for connecting the hub to the main bearing in the nacelle. Fig. 9 illustrates that the hub 5 is provided with an opening 20 in the first part 16, which hole corresponds to the air inlet opening 11 in the spinner. Brackets 21 and 22 are arranged on the hub. These brackets are used for connecting the spinner to the hub.

In fig. 8 a mini spinner 9 is illustrated, in which connection means 23 and 24 are illus- trated which are intended for cooperation with the brackets 21 and 22 in order to attach the spinner to the hub.

In fig. 8 it is shown that the air inlet is a hole 25 which is recessed from an outermost portion 26 of the top part 12. Hereby, it is possible to provide rounding around the hole 25. Furthermore, fig. 8 illustrates that the air inlet 11 is provided with a tubular extension 27 in which the water separator 40 is arranged.

One can see that the water separator 40 is built-in into the tubular extension 27. The tubular extension 27 is at the opening limited by an annular ridge 41 having a diame- ter less than the diameter of the tubular extension 27. The water separator has an outer diameter corresponding to the diameter of the tubular extension. Hereby the water separator 40 will fit snugly in the tubular extension 27. Accordingly the water separator 40 cannot be mounted or dismounted through the hole 25. The water separator 40, or at least the outer part thereof may be is manufactured integrally with the spinner 9.

As the air inlet 11 in the hub 5 is provided with a water separator, it is not possible to enter into the hub through the air inlet 11.

Accordingly, the manholes 14 are provided. As illustrated in figs. 2, 3 and 9 the manhole 14 is provided in the second part 17 of the hub 5. Hereby, it is easy to enter into the hub from the top of the nacelle 4. In the drawings only one man hole is illustrated. However, a manhole 14 will be provided between each of the three rotor blades 6. Accordingly, a manhole 14 could be directed upwards for a person to enter into the hub, and the manholes which are directed downwards, could be used for hoisting elements down from the hub and up into the hub.

Fig. 4 shows the mini spinner which is also illustrated in fig. 3 and 8.

The spinner has a parabolic or semi-spherical outer shape at the top part 12. From the top part the spinner is provided with shirt parts 28 which are intended for extending to a position between the first connection means 18 for the rotor blades. Hereby, the first part 16 of the hub is covered and parts of the hub arranged between the first connection means are also covered by the mini spinner.

Fig. 3 illustrates that separate cover parts 29 are arranged for covering the first con- nection means (not visible in fig. 3). These separate cover parts 29 will cover the pitch bearing. The separate cover parts 29 will typically be provided in three or more segments, which are mounted after the mounting of the rotor blades. In fig. 2 it is seen that the full spinner 9 comprises portions 30 which cover the first connection means 18(see fig. 9).

In figs. 2 and 3 a separate cover part 31 is illustrated which is used for covering the second connection means 19. The separate cover parts would preferably be provided in three or more segments.

The full spinner 9 illustrated in fig. 2 will cover the first part 16 of the hub and the second part 17 of the hub and also the part of the hub arranged between the first con- nection means and will, as explained above, also cover the first connection means 18.

Accordingly, the hub system comprising a full spinner only requires the use of the separate cover parts 31 for the second connection means. Fig. 5 illustrates an embodiment for a manhole 14 and a hatch 15 covering said manhole. The hatch 15 is provided with a surface 32 which is flush with a surface 33 surrounding the manhole.

This is also clear from fig. 6 in which the hatch 15 is partially opened. Between the surfaces 32 and 33 a groove 34 is arranged which allows the hatch to swing open around a hinge 35 (see fig. 6).

As seen in fig. 6 the hatch 15 is intended to swing inwardly into the hub. Hereby, a security measure is obtained, seeing that it will not open accidently in case a person steps on the hatch.

The hatch 15 is provided with a handle 36. The handle 36 is provided in a countersunk hole 37 in the surface 32 of the hatch 15. In fig. 6 it is also seen that a flange part 38 is provided around the hatch in order to rest against an inner surface 39 of the manhole 14. This increases the security of the hatch. As it most clearly occurs from fig. 5 it is seen that the manhole 14 is oval. Hereby, the manhole is adapted to a person and also a more strong construction is obtained compared to a circular manhole. Fig. 7 illustrates another embodiment for the hatch. It is noted that the manhole 14 is illustrated as circular. However, it is preferred that the man hole is oval. fig. 7 illustrates another embodiment for the hatch.

The hatch would have a totally plane surface 32 without any countersunk openings for the handle 36. Accordingly, the handle will extend above the outer surface 32 of the hatch 15. The handle will extend through the hatch and have a corresponding handle on the inside (not illustrated). Hereby, it is possible to open the hatch from both the outside and the inside. The plane outer surface 15 of this hatch is flush with a surface 33 surrounding the man- hole 14. Only a small groove 34 is provided. Accordingly, this embodiment provides a hatch which is flush with the surrounding outer surface. Hereby, a substantially closed surface is provided as seen from the outside of the hub 5. This embodiment will obviate the risk that water is agglomerated in the area around the handle, which could be a problem with a handle illustrated in fig. 6.

It is noted that the embodiments illustrated above are examples, and that modifications are possible. It is also possible to combine the features from different embodiments.