(19)
(11)EP 3 751 133 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
15.03.2023 Bulletin 2023/11

(21)Application number: 19180271.9

(22)Date of filing:  14.06.2019
(51)International Patent Classification (IPC): 
F03D 1/06(2006.01)
(52)Cooperative Patent Classification (CPC):
F03D 1/0675; F05B 2240/302; F05B 2250/292; Y02E 10/72

(54)

ROTOR BLADE FOR A WIND TURBINE

ROTORBLATT FÜR EINE WINDTURBINE

PALE DE ROTOR POUR ÉOLIENNE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(43)Date of publication of application:
16.12.2020 Bulletin 2020/51

(73)Proprietor: Siemens Gamesa Renewable Energy A/S
7330 Brande (DK)

(72)Inventors:
  • Burchardt, Claus
    9260 Gistrup (DK)
  • Hurup, Allan
    9240 Nibe (DK)
  • Nielsen, Mogens
    9220 Aalborg (DK)

(74)Representative: SGRE-Association 
Siemens Gamesa Renewable Energy GmbH & Co KG Schlierseestraße 28
81539 München
81539 München (DE)


(56)References cited: : 
EP-A1- 2 749 765
CN-A- 102 200 100
US-A1- 2018 238 300
WO-A1-2018/215457
US-A1- 2017 145 986
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description


    [0001] The invention relates to a rotor blade for a wind turbine, comprising a hollow blade body with a root and a tip.

    [0002] Wind turbines usually comprise at least two, in most appliancies three rotor blades which are attached to a hub. The rotor blades interact with the wind making the hub rotate. As the hub is coupled to a generator, electric energy is produced as is commonly known.

    [0003] Wind turbines are installed on shore, but also offshore wind turbines are well known. Especially offshore wind turbines were increased in size over the years. With an increasing height of the wind turbine tower, also the length of the rotor blades increases. This makes the production and transportation of the rotor blade difficult. Prior art examples are disclosed in WO2018/215457A1 and US2018/238300A1.

    [0004] It is an object of the invention to provide an improved rotor blade.

    [0005] For solving the problem a rotor blade for a wind turbine, comprising a hollow blade body with a root and a tip, is provided, which is characterised in that the blade body is split along a split plane into two body parts, one extending from the root to a first connection section and the other extending from a second connection section to the tip, wherein the first and the second connection sections are adapted to overlap each other in the connected position.

    [0006] The inventive rotor blade is split into two blade body parts, which are due to their reduced length easier to produce. Also the handling and transportation to the installation side is simplified. They can then be connected to each other on site, so that the complete long rotor blade may then be mounted to the hub.

    [0007] In an embodiment not covered by the invention the split plane is in an area where the blade has a convex peripheral geometry. The overall shape of the rotor blade usually changes a lot from the root, where the cross section is cylindrical, to the tip having an air foil like cross section. Over the length, usually starting close to the root, the circumference respectively the cross section widens to a maximum and gets smaller towards the tip, also changing the cross section geometry. According to an embodiment not covered by the invention, the split plane is arranged in an area, where the blade has a convex peripheral geometry, seen from the side of the blade. In this area the cross section respectively the circumference either still widens, is in its maximum or reduces slightly, but in any way is relatively large, so that a large overlap of the first and second connection section in the connected position is realised.

    [0008] In an embodiment not covered by the invention it is also possible to arrange the split plane in an area where the rotor blade has a single curved cross section seen in the direction from the root to the tip. A singled curved cross section means that the cross section has a circular, oval or egg-shaped form. It does not change the direction, but has always, seen from the inner of the blade, a convex circumference along the split plane. This geometry in the split plane region is advantageous for a simple connection of the two body parts.

    [0009] According to the invention, the split plane is in an area where the blade has a convex peripheral geometry and where it has a single curved cross section seen in the direction from the root to the tip. In this embodiment the split plane is arranged in an area where a convex peripheral geometry and a single curved cross section is given. This embodiment allows to combine the positive effects of both split plane positions. Both possible positions enhance the structural performance and enable a lighter and stronger connection. According to the invention both of these possible positions are chosen for arranging this split plane, the positive structural and mechanical advantages can be used.

    [0010] In a further embodiment of the rotor blade the first connection section and the second connection section have a conical geometry adapted to insert one connection section into the other connection section. This conical geometry allows for an easier alignment and assembly of the two body parts, while also the overlapping section allows for a simple but mechanically strong connection of the body parts. The respective conical geometries at both connection sections are quite simple to produce and allow a simple assembly, as both connection sections simply need to be pushed into one another.

    [0011] In an alternative to providing the conical geometries at the connection sections, it is possible that at least one connection section has a stepped geometry. This connection section preferably has a reduced diameter and an abutment shoulder. The other connection section has a larger inner diameter, so that the stepped connection section can be pushed into the other connection section, which abuts with its front surface at the abutment shoulder. It is certainly also possible to provide such an abutment shoulder also at the second connection section, which may have a larger inner diameter at the connection section, so that both connection sections are stepped, one having a reduced outer diameter, the other having an enlarged inner diameter, and are pushed into one another overlapping each other and abutting at the respective abutment shoulders.

    [0012] In any way, no matter if the conical geometry or the stepped geometry is provided at the connection section(s), the connection sections are designed for interlocking with a form fit, so that they perfectly fit into one another. This form fit interlocking means that in the overlapping area the body parts respectively connection sections are attached to each other without larger gaps or slits, but are directly attached to each other, so that a certain fixture is already given right after attaching the body parts to each other without providing special fixation or connection means.

    [0013] Preferably the first connection section being provided at the body part comprising the root is inserted into the second connection section being provided at the body part with the tip.

    [0014] Another preferred embodiment is characterised in that at the first connection section and/or at the second connection section one or more slits extending from the end edge over at least a part of the length of the connection section are provided. While at least one slit is advantageous, preferably several slits, arranged around the circumference and equally distanced to each other, are provided. This slit or these slits enhance the flexibility of the first and/or second connection section, which allows an even better form fit connection of the body parts. The slit or the slits are directed towards the root respectively the tip. If more than one slit is provided, the slits define a kind of flexible fingers extending at the free end edge of the respective connection section.

    [0015] For connecting the body parts respectively for stiffening the connection a connection or stiffening means extending at the inner surfaces and bridging the transition region from the first connection section to the second connection section are provided. These connection or stiffening means are preferably arranged or attached to the inner surface, so that the outer surface is smooth and both body parts merge without a remarkable step or shoulder or groove at the outer surface.

    [0016] The connection or stiffening means comprises one or more webs or sheets attached to the inner surface. These webs or sheets allow to cover larger areas and are quite easy to be very firmly attached to the respective inner surface. Among these webs or sheets the connection or stiffening means may comprise at least one web or sheet extending along the inner circumference for at least 360 degrees. This ring-shaped web or sheet covers the whole ring-shaped transition area and is attached to both inner surfaces of the body parts. It may extend remarkably far into the respective body parts, so that the attachment area or region at both body parts is remarkably large for firmly anchoring the web or sheet at the respective surfaces.

    [0017] Alternatively or additionally the connection or stiffening means may also comprise several band- or strip-like webs or sheets extending in a longitudinal direction over the transition region and being distanced to each other along the inner circumference. The band- or strip-like webs or sheets are also firmly anchored and fixed to the respective inner surfaces bridging the transition region. They are preferably arranged together with the circular web or sheet and extend into the respective body parts even longer than this ring-shaped web or sheet. The band- or strip-like webs or sheets are preferably equally distanced to each other arranged along the inner circumference, so that a uniform distribution is realised.

    [0018] The webs or sheets, no matter which web or sheet is attached, are preferably attached by means of a hardened bonding agent, by lamination or by vacuum assisted resin transfer molding. There are several ways to tightly anchor or embed the webs at the respective surfaces. No matter which way is chosen, they all are based on bonding or gluing the respective web tightly to the respective body part.

    [0019] The split plane itself is preferably at the inboard section of the blade body closer to the root, as in this area preferably the respective convex and single curved geometry is provided.

    [0020] Beside the rotor blade itself the invention also refers to a wind turbine, comprising a rotor blade with at least one rotor blade as described above.

    [0021] Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. The drawings, however, are only principle sketches design solely for the purpose of illustration and do not limit the invention. The drawings show:
    Fig. 1
    shows a principle sketch of an inventive wind turbine comprising three inventive rotor blades,
    Fig. 2
    shows a perspective exploded sketch of an inventive rotor blade of a first embodiment,
    Fig. 3
    shows a partial sketch of a cross section of the rotor blade in the connection area of the two body parts with a web-like connection of stiffening means being provided,
    Fig. 4
    shows a sketch according to fig. 3 with further web-like connection or stiffening means being provided, and
    Fig. 5
    shows a principle sketch of an inventive rotor blade according to a second embodiment in an exploded view.


    [0022] Fig. 1 shows an inventive wind turbine 1, comprising a tower 2 with a nacelle 3 and a hub 4, at which hub in this embodiment three inventive rotor blades 5 are attached. As commonly known, the rotor blades 5 interact with the wind making the hub 4 rotate. This rotation drives a generator arranged in the nacelle 3 for producing electric energy.

    [0023] Fig. 2 shows a principle sketch in form of an exploded view of a rotor blade 5 according to a first embodiment. In the following several embodiments are described. The same reference numbers will be used for the same or comparable parts of the respective embodiment.

    [0024] The rotor blade 5 as shown in fig. 2 comprises a hollow blade body 6 which is split along a split plane 7 into two body parts 8, 9, which can be, as shown by the arrows P, pushed into each other respectively connected to each other. The first blade body 8 extends from a root 10 to a first connection section 11, while the second body part 9 extends from a second connection section 12 to a tip 13.

    [0025] In the connected position, as shown in fig. 3, which shows a partial cross sectional view of the rotor blade 5 of fig. 2, the body parts 8, 9 are pushed with their respective connection section 11, 12 into each other, wherein in this embodiment the first connection section 11 of the first body part 8 is pushed into the second connection section 12 of the second body part 9. As fig. 3 shows, both connection sections 11, 12 are conical allowing for a simple alignment and assembly of the connection sections 11, 12 and for attaching them to each other with a form fit as shown in fig. 3.

    [0026] The split plane 7 is arranged in an area of the rotor blade 5, where the blade has, as shown in fig. 3, a convex peripheral geometry seen from the side of the blade. As can be clearly seen in fig. 3, the circumference widens from the left to a kind of maximum circumference in the area of the split plane 7 and narrows then again.

    [0027] Furthermore the split plane 7 is arranged in an area where the blade has a single curved cross section, as is shown in the exploded view in fig. 1. The cross section of the connection sections 11, 12 is circular respectively oval, thus the connection sections have a single curved cross section respectively are convex all around the circumference seen from the inner of the blade. Arranging the split plane 7 in the convex and single curved area as explained above enhances the structural performance and enables a lighter and stronger connection of both body parts 8, 9 together with the form fit connection of the connection sections 11, 12 preferably via the conical geometries of the connection sections 11, 12.

    [0028] Fig. 3 shows a connection or stiffening means 22 being provided at the inner surfaces 14, 15 of the respective body parts 8, 9 respectively the respective connection sections 11, 12. This connection or stiffening means 13 comprises a web 16, for example a glass fiber web or carbon fiber web or the like, which has a ring form and extends around at least 360 degrees along the inner circumference covering the transition region 17, where the inner surface 14 changes to the inner surface 15. The web 16 extends in the longitudinal direction into both body parts 8, 9 and overlaps a certain area of the inner surfaces 14, 15, to which it is tightly embedded by means of a hardened bonding agent or by lamination or by vacuum assisted resin transfer molding or the like. This web 16 connects the body parts 8, 9 and stiffens the connection and also transfers the shear loads from one body part to the other body part.

    [0029] Fig. 4 shows a view according to fig. 3, where in addition to the web 16 several further band- or strip-like webs 18 are attached to the respective inner surfaces 14, 15 extending even further into the respective body part 8, 9. They obviously extend over the web 16 and the respective transition region 17 and are used for further improving the connection respectively the stiffening and the shear load transfer.

    [0030] Certainly additional fixation mean may be used for fixing the body parts 8, 9 to each other in the overlapping connection sections, for example bolt-nut-connections or the like, which are not shown in detail. It is clear that the connection of the body parts 8, 9 needs to be as firm as possible due to the forces acting on the rotor blade and thus on the connection area when in motion.

    [0031] Finally fig. 5 shows another embodiment of an inventive rotor blade 5 again comprising a hollow blade body 6 which is split along a split plane 7 into two body parts 8, 9, the one extending from the root 10 to a first connection section 11 and the other one extending from a second connection section 12 to a tip 13. Also in this embodiment the split plane 7 is provided in an area where the rotor blade 5 has a convex peripheral geometry seen from the side of the blade and where it has a single curved cross section seen in the direction from the root to the tip, as already explained with regard to fig. 1.

    [0032] In this embodiment the connection section 11 shows several slits 19 extending from the end edge 20 over at least a part of the length of the connection section 11. These slits 19 are preferably equally distributed around the circumference and define respective flexible fingers 21. These flexible fingers 21 enhance the flexibility of the connection section 11 which is advantageous for the good form fit of the connection sections 11, 12.

    [0033] While the fingers 21 are only provided at the first connection section 11, it is also possible to provide the second connection 12 with the respective fingers 21 or to provide both connections 11, 12 with fingers 21.


    Claims

    1. Rotor blade for a wind turbine, comprising a hollow blade body (6) with a root (10) and a tip (13), whereby the blade body (6) is split along a split plane (7) into two body parts (8, 9), one extending from the root (10) to a first connection (11) section and the other extending from a second connection (12) section to the tip (13), wherein the first and the second connection sections (11, 12) are adapted to overlap each other in the connected position, characterised in that the split plane (7) is in an area where the rotor blade (5) has a convex peripheral geometry seen from the side of the blade and where it has a single curved cross section seen in the direction from the root (10) to the tip (13).
     
    2. Rotor blade according to claim 1, characterised in that the cross section is circular or oval or egg-shaped.
     
    3. Rotor blade according to claim 1 or 2, characterised in that the first connection section (11) and the second connection section (12) have a conical geometry adapted to insert one connection section (11) into the other conection section (12).
     
    4. Rotor blade according to claim 1 or 2, characterised in that at least one connection section (11, 12) has a stepped geometry.
     
    5. Rotor blade according to claim 3 or 4, characterised in that the connection sections (11, 12) are interlocked with a form fit.
     
    6. Rotor blade according to one of the claims 3 to 5, characterised in that the first connection section (11) is inserted into the second connection section (12).
     
    7. Rotor blade according to one of the claims 3 to 6, characterised in that at the first connection section (11) and/or at the second connection section (12) one or more slits (19) extending from the end edge (20) over at least a part of the length of the connection section (11) are provided.
     
    8. Rotor blade according to one of the preceding claims, characterised in that connection or stiffening means (13) extending at the inner surfaces (14, 15) and bridging the transition region (17) from the first connection section (11) to the second connection section (12) are provided.
     
    9. Rotor blade according to claim 8, characterised in that the connection or stiffening means (13) comprises one or more webs (16, 18) or sheets attached to the inner surfaces (14, 15).
     
    10. Rotor blade according to claim 9, characterised in that the connection or stiffening means (13) comprises at least one web (16) or sheet extending along the inner circumference for at least 360 degrees.
     
    11. Rotor blade according to claim 9 or 10, characterised in that the connection or stiffening means (13) comprises several band- or strip-like webs (18) or sheets extending in a longitudinal direction over the transition region and being distanced to each other along the inner circumference.
     
    12. Rotor blade according to one of the claims 9 to 11, characterised in that the webs (16, 18) or sheets are attached by means of a hardened bonding agent, by lamination or by vacuum assisted resin transfer molding.
     
    13. Rotor blade according to one of the preceding claims, characterised in that the split plane (7) is at the inboard section of the blade body (6).
     
    14. Wind turbine, comprising a rotor with at least one rotor blade (5) according to one of the preceding claims.
     


    Ansprüche

    1. Rotorblatt für eine Windenergieanlage, umfassend einen hohlen Blattkörper (6) mit einem Fuß (10) und einer Spitze (13), wobei der Blattkörper (6) entlang einer Teilungsebene (7) in zwei Körperteile (8, 9) geteilt ist, wobei sich einer von dem Fuß (10) zu einem ersten Verbindungs(11)-Abschnitt erstreckt und der andere von einem zweiten Verbindungs(12)-Abschnitt zu der Spitze (13) erstreckt, wobei der erste und der zweite Verbindungsabschnitt (11, 12) dazu ausgelegt sind, einander in der verbunden Position zu überlagern, dadurch gekennzeichnet, dass die Teilungsebene (7) in einem Bereich liegt, in dem das Rotorblatt (5) bei Ansicht von der Seite des Blatts eine konvexe Umfangsgeometrie aufweist und in dem es bei Ansicht in der Richtung von dem Fuß (10) zu der Spitze (13) einen einzelnen gebogenen Querschnitt aufweist.
     
    2. Rotorblatt nach Anspruch 1, dadurch gekennzeichnet, dass der Querschnitt kreisförmig oder oval oder eiförmig ist.
     
    3. Rotorblatt nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass der erste Verbindungsabschnitt (11) und der zweite Verbindungsabschnitt (12) eine konische Geometrie aufweisen, die dazu ausgelegt ist, einen Verbindungsabschnitt (11) in den anderen Verbindungsabschnitt (12) einzusetzen.
     
    4. Rotorblatt nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass mindestens ein Verbindungsabschnitt (11, 12) eine gestufte Geometrie aufweist.
     
    5. Rotorblatt nach Anspruch 3 oder 4, dadurch gekennzeichnet, dass die Verbindungsabschnitte (11, 12) mit einem Formschluss ineinandergreifen.
     
    6. Rotorblatt nach einem der Ansprüche 3 bis 5, dadurch gekennzeichnet, dass der erste Verbindungsabschnitt (11) in den zweiten Verbindungsabschnitt (12) eingesetzt ist.
     
    7. Rotorblatt nach einem der Ansprüche 3 bis 6, dadurch gekennzeichnet, dass an dem ersten Verbindungsabschnitt (11) und/oder an dem zweiten Verbindungsabschnitt (12) ein oder mehrere Schlitze (19), die sich von der Endkante (20) über zumindest einen Teil der Länge des Verbindungsabschnitts (11) erstrecken, bereitgestellt sind.
     
    8. Rotorblatt nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass Verbindungs- oder Versteifungsmittel (13), die sich an den Innenflächen (14, 15) erstrecken und den Übergangsbereich (17) von dem ersten Verbindungsabschnitt (11) zu dem zweiten Verbindungsabschnitt (12) überbrücken, bereitgestellt sind.
     
    9. Rotorblatt nach Anspruch 8, dadurch gekennzeichnet, dass das Verbindungs- oder Versteifungsmittel (13) eine oder mehrere Rippen (16, 18) oder Platten umfasst, die an den Innenflächen (14, 15) angebracht sind.
     
    10. Rotorblatt nach Anspruch 9, dadurch gekennzeichnet, dass das Verbindungs- oder Versteifungsmittel (13) mindestens eine Rippe (16) oder Platte umfasst, die sich entlang des Innenumfangs für mindestens 360 Grad erstreckt.
     
    11. Rotorblatt nach Anspruch 9 oder 10, dadurch gekennzeichnet, dass das Verbindungs- oder Versteifungsmittel (13) mehrere band- oder streifenartige Rippen (18) oder Platten umfasst, die sich in einer Längsrichtung über den Übergangsbereich erstrecken und entlang des Innenumfangs voneinander beabstandet sind.
     
    12. Rotorblatt nach einem der Ansprüche 9 bis 11, dadurch gekennzeichnet, dass die Rippen (16, 18) oder Platten mittels eines gehärteten Bindemittels, durch Laminieren oder durch vakuumunterstütztes Harzspritzpressen angebracht sind.
     
    13. Rotorblatt nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass sich die Teilungsebene (7) an dem innenliegenden Abschnitt des Blattkörpers (6) befindet.
     
    14. Windenergieanlage, umfassend einen Rotor mit mindestens einem Rotorblatt (5) nach einem der vorhergehenden Ansprüche.
     


    Revendications

    1. Pale de rotor pour une éolienne, comprenant un corps de pale creux (6) avec un pied (10) et une pointe (13), dans laquelle le corps de pale (6) est divisé le long d'un plan de séparation (7) en deux parties de corps (8, 9), l'une s'étendant à partir du pied (10) jusqu'à une première section de connexion (11) et l'autre s'étendant à partir d'une deuxième section de connexion (12) jusqu'à la pointe (13), dans laquelle la première et la deuxième sections de connexion (11, 12) sont adaptées pour se chevaucher en position connectée, caractérisée en ce que le plan de séparation (7) est dans une zone où la pale de rotor (5) a une géométrie périphérique convexe vue du côté de la pale et où elle a une seule section transversale incurvée vue dans la direction allant depuis le pied (10) à la pointe (13).
     
    2. Pale de rotor selon la revendication 1, caractérisée en ce que la section transversale est circulaire ou ovale ou ovoïde.
     
    3. Pale de rotor selon la revendication 1 ou 2, caractérisée en ce que la première section de connexion (11) et la deuxième section de connexion (12) ont une géométrie conique adaptée pour insérer une section de connexion (11) dans l'autre section de connexion (12).
     
    4. Pale de rotor selon la revendication 1 ou 2, caractérisée en ce qu'au moins une section de connexion (11, 12) présente une géométrie étagée.
     
    5. Pale de rotor selon la revendication 3 ou 4, caractérisée en ce que les sections de connexion (11, 12) sont imbriquées avec un ajustement de forme.
     
    6. Pale de rotor selon l'une des revendications 3 à 5, caractérisée en ce que la première section de connexion (11) est insérée dans la deuxième section de connexion (12).
     
    7. Pale de rotor selon l'une des revendications 3 à 6, caractérisée en ce qu'au niveau de la première section de connexion (11) et/ou au niveau de la deuxième section de connexion (12) sont prévues une ou plusieurs fentes (19) s'étendant depuis le bord d'extrémité (20) jusqu'à au moins une partie de la longueur de la section de connexion (11).
     
    8. Pale de rotor selon l'une des revendications précédentes, caractérisée en ce que sont prévus des moyens de connexion ou de rigidification (13) s'étendant au niveau des surfaces intérieures (14, 15) et reliant la région de transition (17) de la première section de connexion (11) à la deuxième section de connexion (12) .
     
    9. Pale de rotor selon la revendication 8, caractérisée en ce que les moyens de connexion ou de rigidification (13) comprennent une ou plusieurs toiles (16, 18) ou feuilles fixées sur les surfaces intérieures (14, 15).
     
    10. Pale de rotor selon la revendication 9, caractérisée en ce que les moyens de connexion ou de rigidification (13) comprennent au moins une toile (16) ou une feuille s'étendant le long de la circonférence intérieure sur au moins 360 degrés.
     
    11. Pale de rotor selon la revendication 9 ou 10, caractérisée en ce que les moyens de connexion ou de rigidification (13) comprennent plusieurs toiles (18) ou feuilles en forme de ruban ou de bande s'étendant dans une direction longitudinale sur la région de transition et étant espacées les unes des autres le long de la circonférence intérieure.
     
    12. Pale de rotor selon l'une des revendications 9 à 11, caractérisée en ce que les toiles (16, 18) ou feuilles sont fixées au moyen d'un agent de liaison durci, par laminage ou par moulage par transfert de résine sous vide.
     
    13. Pale de rotor selon l'une des revendications précédentes, caractérisée en ce que le plan de séparation (7) se trouve au niveau de la section intérieure du corps de pale (6).
     
    14. Éolienne, comprenant un rotor avec au moins une pale de rotor (5) selon l'une des revendications précédentes.
     




    Drawing














    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description