Abstract:
A wind turbine rotor blade handling system for moving a wind turbine rotor blade is provided. The wind turbine rotor blade comprises a root portion, a tip portion and a rotor blade longitudinal rotational axis extending from the root portion to the tip portion. Furthermore, the wind turbine rotor blade handling system comprises a rotary device to rotate the wind turbine rotor blade about the rotor blade longitudinal rotational axis. The rotary device is arranged and prepared for being fastened to the tip portion. Additionally, a method of moving the wind turbine rotor blade by means of the wind turbine rotor blade handling system is also provided.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to EP 13169955.5, having a filing date of May 31, 2013, the entire contents of which are hereby incorporated by reference. 
       FIELD OF TECHNOLOGY 
       [0002]    The following relates to a wind turbine rotor blade handling system for moving a wind turbine rotor blade, and a method of moving a wind turbine rotor blade by means of such a handling system. 
       BACKGROUND 
       [0003]    Rotor blades need to be handled, i.e. moved or transported, during manufacturing of the rotor blade and afterwards. A current wind turbine rotor blade typically exhibits a size, i.e. a maximum extension, of at least 50 m and can reach a size of up to 100 m. Thus, handling of such a wind turbine rotor blade is challenging. 
         [0004]    Current rotor blade handling systems comprise at least two parts, a root part and a tip part. To rotate the wind turbine rotor blade, the wind turbine rotor blade is rotated by the root part. In other words, a root portion of the wind turbine rotor blade is supported by the root part and rotated by an appropriate mechanism. Meanwhile, a tip portion of the wind turbine rotor blade is fixed by the tip part. The tip portion may be fixed in a disk, and the rotation at the root part may be performed by powered rollers. 
         [0005]    A disadvantage of current rotor blade handling systems is that the tip portion is rigidly fixed in the tip part and thus deflection of the wind turbine rotor blade during handling, e.g. during rotation, is difficult or impossible. This causes a problem because of high loads and high forces which are exerted on the rotor blade during rotation. As a consequence, handling of a wind turbine rotor blade is complicated and damages to the wind turbine rotor blade occur frequently. 
       SUMMARY 
       [0006]    Thus, there exists a need to provide an improved system for handling a wind turbine rotor blade with fewer damages to the wind turbine rotor blade caused by the handling compared to the state of the art. 
         [0007]    An aspect relates to a wind turbine rotor blade handling system for moving a wind turbine rotor blade. The wind turbine rotor blade comprises a root portion, a tip portion and a rotor blade longitudinal rotational axis extending from the root portion to the tip portion. Furthermore, the wind turbine rotor blade handling system comprises a rotary device which is suited to rotate the wind turbine rotor blade about the rotor blade longitudinal rotational axis. The rotary device is arranged and prepared for being fastened to the tip portion. 
         [0008]    A wind turbine rotor blade is arranged and prepared for being a part of a wind turbine. A wind turbine is a device that can convert wind energy, i.e. kinetic energy from wind, into mechanical energy. Advantageously, the mechanical energy is subsequently used to generate electricity. A wind turbine is also referred to as a wind power plant or a wind charger. Furthermore, a wind turbine may also be referred to as a wind turbine engine. 
         [0009]    In this application, the wind turbine rotor blade is also simply denoted as a rotor blade. The rotor blade comprises a root, a main body and a tip. At the root, the rotor blade is attached to a hub of a wind turbine. The tip may be characterized as a part of the rotor blade which is most distal from the root. The rotor blade may thus be divided in the root portion, the tip portion and a main body portion. The root portion may be characterized as a portion of the rotor blade which includes the root and the portion around the root. The root portion may comprise up to 20%, in particular up to 10%, of the whole rotor blade. Analogously, the tip portion may be characterized as a portion of the rotor blade which includes the tip and the portion around the tip. The tip portion may be characterized as the portion of the rotor blade where a tip stand is attached to the main body portion. Regarding the maximum extension of the rotor blade, i.e. its maximum length, the tip portion may comprise up to 50% of the total length of the rotor blade. Furthermore, the rotor blade may comprise a trailing edge and a leading edge. 
         [0010]    The rotor blade may comprise an axis of symmetry and the rotor blade may be symmetrical regarding rotation of the rotor blade about the axis of symmetry. However, due to an optimal profile of the rotor blade, the rotor blade is not fully symmetrical. 
         [0011]    A length of the rotor blade longitudinal rotational axis, which extends from the root portion to the tip portion, may be referred to as a maximum extension of the rotor blade. If the rotor blade comprises an axis of symmetry, the rotor blade longitudinal rotational axis may be equal to the axis of symmetry. 
         [0012]    The rotary device may be fastened directly or indirectly to the tip portion. The rotary device is, for example, a part of another device, which is fixed to the tip portion. This other device may be referred to as a tip part of the wind turbine rotor blade handling system. The rotary device may be attached to a chain, which runs around a disk, which secures the tip portion. Thus, by means of the chain, the rotary device may be able to rotate the rotor blade. 
         [0013]    By stating that the rotary device is fastened to the tip portion, in the context of this application, it is meant that the rotary device is attached or connected or joined or secured to the tip portion. 
         [0014]    Functions of the tip part may be: supporting the rotor blade on the handling system, securing the rotor blade in a fixed position, and rotating the rotor blade. 
         [0015]    Embodiments of the wind turbine rotor blade handling system as described above may be flexible and can adapt to various rotor blade positions. This can result in smaller loads on the rotor blade. As a consequence, a risk of damages to the rotor blade is reduced. 
         [0016]    Embodiments of a wind turbine rotor blade handling system may be denoted as a rotor blade handling system or as a handling system. 
         [0017]    In an exemplary embodiment, the wind turbine rotor blade handling system comprises a pivot mechanism by which the wind turbine rotor blade can be rotated about a rotational axis. The rotational axis is substantially perpendicular to the rotor blade longitudinal rotational axis. 
         [0018]    In an exemplary embodiment, if a first axis is referred to as being substantially perpendicular to a second axis, a deviation of up to 20°, in particular of up to 10°, more particularly of up to 5°, is comprised. Analogously, if a first axis is referred to as being substantially parallel to a second axis, a deviation of up to 20°, in particular of up to 10°, more particularly of up to 5°, is comprised as well. Thus, specifically in this embodiment, the rotational axis comprises an angle with the rotor blade longitudinal rotational axis, which is at least 70°, in particular at least 80°, more particularly at least 85°. 
         [0019]    The pivot mechanism of the rotor blade handling system can be advantageous when moving or transporting the rotor blade. Due to the pivot mechanism loads and forces, which are exerted on the rotor blade during transportation or moving, may be reduced compared to a fixed attachment of the rotor blade to the rotor blade handling system. 
         [0020]    In another exemplary embodiment, the pivot mechanism comprises a first pivot device by which the wind turbine rotor blade can be rotated about a first transversal rotational axis. Additionally, the pivot mechanism comprises a second pivot device by which the wind turbine rotor blade can be rotated about a second transversal rotational axis. Furthermore, the first transversal rotational axis and the second transversal rotational axis are substantially perpendicular to each other. By having two transversal rotational axes being substantially perpendicular to each other and each one being substantially perpendicular to the rotor blade longitudinal rotational axis, any movement in a plane, which is perpendicular to the rotor blade longitudinal rotational axis, is possible. When also counting the movement around the rotor blade longitudinal rotational axis, even any movement in space is possible. In other words, three degrees of freedom are comprised by the handling system. 
         [0021]    The first pivot device and/or the second pivot device may comprise a hinge or a joint. 
         [0022]    In an exemplary embodiment, the wind turbine rotor blade handling system comprises a tip part frame and a tip part securing means for securing the tip portion to the tip part frame. The tip part securing means may comprise a clamping yaw, a mounting bracket and/or a strap. A requirement for the tip part securing means is, on the one hand, that the rotor blade is secured safely and in a fixed manner. On the other hand, the rotor blade, e.g. a surface of the rotor blade and/or a structural element of the rotor blade, is not damaged by the tip part securing means. The tip part frame may comprise iron. Embodiments of the tip part frame may be mechanically rigid and stable. 
         [0023]    In an exemplary embodiment, the wind turbine rotor blade handling system comprises a height adjustment means by which the wind turbine rotor blade can be raised and/or lowered relative to a plane where the wind turbine rotor blade handling system is set up. A handling system which is height adjustable can be advantageous. When a rotor blade is transported, it may first be secured to the tip part frame in a low position. When securing is finished, it is, for instance, raised and subsequently the rotor blade is moved by means of the rotor blade handling system. 
         [0024]    The plane where the wind turbine rotor blade handling system is set up is also referred to as a ground, where the handling system is put or is positioned. If the ground is substantially horizontal, the height adjustment means has, for example, a function to vertically adjust the rotor blade. 
         [0025]    The height adjustment means may comprise a height adjustment mechanism that works hydraulically. The rotor blade may be raised and/or lowered up to 10 m (metre), in particular up to 2 m. 
         [0026]    In an exemplary embodiment, the wind turbine rotor blade handling system comprises a root supporting element which is arranged and prepared for supporting the root portion. 
         [0027]    To efficiently move the rotor blade, a second part, which is referred to as a root part, may be used. Due to the length of the rotor blade, which may at least be 50 m in current industrial type applications, and which may reach up to 100 m, the root part may be a separate part relative to the tip part. A function of the root part, in particular the root supporting element, is to support the rotor blade, in particular the root portion, during transportation. The root supporting element may also support the rotor blade during storage. 
         [0028]    Embodiments of the root supporting element comprises a root part frame and at least one roller. The root part frame and the roller are joined with each other. The root part frame may hold the roller in an optimal position with respect to the root portion. The roller may be pivoted relative to the root part frame. The roller interacts with the root portion by, for instance, surface friction. The roller may comprise polyurethane. In an exemplary embodiment, the root supporting element comprises four rollers. 
         [0029]    In another exemplary embodiment, the roller comprises a roller longitudinal rotational axis. The roller longitudinal rotational axis and the rotor blade longitudinal rotational axis are substantially parallel to each other. 
         [0030]    Thus, if the rotor blade is rotated, e.g. by the rotary device located at the tip part, the rotor blade rotates in an opposite direction compared to the roller. In other words, if, for instance, the rotor blade is rotated clockwise, the roller may rotate counter clockwise. 
         [0031]    In another exemplary embodiment, the wind turbine rotor blade handling system comprises a roller blocking mechanism for preventing a rotational movement of the roller about the roller longitudinal rotational axis. Thus, the roller can be actively controlled and locked or unlocked. If, for example, the rotor blade is stored or moved in a linear direction, the roller is locked and rotation of the rotor blade is prevented. If, however, it is desired that the rotor blade shall be rotated, then, the roller is actively unlocked. 
         [0032]    In an exemplary embodiment, the roller comprises a shape of a circular cylinder. A diameter of the roller may be in a range between 20 cm (centimetre) and 60 cm. In particular, the diameter may be in a range between 40 cm and 50 cm. A length of the roller may be in a range between 20 cm and 100 cm. In one embodiment, it is in a range between 40 cm and 80 cm. The length of the roller may correlate with a length of the rotor blade, i.e. for handling a long rotor blade a longer roller is used than for handling a short rotor blade. However, the length of the roller may correlate with a specific design of the rotor blade and the surface pressure between the rollers and the rotor blade. 
         [0033]    In another exemplary embodiment, the root part frame comprises a root part frame cubature that is substantially equal to a root portion curvature of the root portion. 
         [0034]    If the root portion comprises a shape of a circular cylinder, an outer radius can be attributed to the root portion. The root supporting element may also comprise a curved shape with an inner radius, which is similar to the outer radius of the root portion. In more general terms, the shape of the root supporting element is adapted to the shape of the root portion. 
         [0035]    In another embodiment, the rotary device comprises at least one motor for realizing a rotational movement of the wind turbine rotor blade about the rotor blade longitudinal rotational axis. The motor may be an electrical motor. Embodiments of the electrical motor has a power between 1 kW (kilowatt) and 5 kW, in particular between 2 kW and 2.5 kW on one axis. It can be beneficial to have several motors as the power of a single motor then is smaller compared to one common motor. 
         [0036]    The motor may be attached to an outer frame of the tip part, the outer frame being non-rotatable compared to other parts of the tip part which can be rotated or pivoted. 
         [0037]    In another embodiment, the rotor blade longitudinal rotational axis is substantially perpendicular to a gravitational force acting on a wind turbine rotor blade during rotation of the wind turbine rotor blade. In other words, if the rotor blade is positioned horizontally, then the rotor blade longitudinal rotational axis is advantageously horizontal as well, a gravitational force acting on the wind turbine rotor blade on its centre of mass. 
         [0038]    In another embodiment, the wind turbine rotor blade handling system comprises a means of transportation for moving the wind turbine rotor blade handling system in a plane which is substantially in parallel to the rotor blade longitudinal rotational axis. If a rotor blade is only needed to be rotated about the rotor blade longitudinal rotational axis, then a means of transportation for moving the rotor blade may not be necessary. If, however, the rotor blade shall be transported from one location to another location, then a means of transportation for moving the rotor blade and/or the handling system may be used. 
         [0039]    In an advantageous embodiment, the means of transportation comprises an arrangement with a plurality of wheels. The arrangement can be stable enough to support the rotor blade. The wheels may be pivotable, i.e. that they can be swivelled. Furthermore, each one of the root part and the tip part may comprise a plurality, in particular at least three, wheels. 
         [0040]    Embodiments of the invention also relate to a method of moving a wind turbine rotor blade by means of a wind turbine rotor blade handling system as described above. In an exemplary embodiment, the method may comprise the following steps:
       a) securing the wind turbine rotor blade with the wind turbine rotor blade handling system, and   b) rotating the wind turbine rotor blade, in particular by the rotary device.       
 
         [0043]    Securing the rotor blade may be done manually or automatically. According to common shapes or profiles of the tip portion, there may be predefined programs for securing the tip portion. 
         [0044]    In step b) it may be possible to rotate the rotor blade about 360° or less. However, it may also be possible that a maximum rotation of only up to 200° or less is possible. 
     
    
     
       BRIEF DESCRIPTION 
         [0045]    Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein: 
           [0046]      FIG. 1  depicts a schematic view of a wind turbine; 
           [0047]      FIG. 2  depicts a schematic view of a wind turbine rotor blade; 
           [0048]      FIG. 3  depicts a schematic view of a tip part of a wind turbine rotor blade handling system; 
           [0049]      FIG. 4  depicts a schematic view of a root part of a wind turbine rotor blade handling system; and 
           [0050]      FIG. 5  depicts a schematic view of a wind turbine rotor blade handling system and a wind turbine rotor blade. 
       
    
    
     DETAILED DESCRIPTION 
       [0051]    Referring to  FIG. 1 , a wind turbine  10  with a tower  11  and a nacelle  12  is shown. The nacelle  12  is connected with a hub  13 . Two wind turbine rotor blades  20  are mounted to the hub  13 . The hub  13 , and thus also the wind turbine rotor blade  20 , can be rotated about a rotor axis of rotation  14 . The wind turbine  10  is a direct drive wind turbine. 
         [0052]    Referring to  FIG. 2 , a wind turbine rotor blade  20  is shown. The wind turbine rotor blade  20  is divided in a root portion  21 , a tip portion  22  and a main body portion  24 . The root portion  21  comprises a shape of a circular cylinder. The root portion  21  comprises a portion of 5% relative to the maximum length of the whole wind turbine rotor blade  20 . The tip portion  22  comprises a portion of 30% relative to the wind turbine rotor blade  20 . 
         [0053]    Furthermore, the wind turbine rotor blade  20  comprises a virtual axis extending from the root portion  21  to the tip portion  22 . This virtual axis is referred to as a rotor blade longitudinal rotational axis  23 . The wind turbine rotor blade  20  comprises a maximum extension, extending from the root portion  21  to the tip portion  22 , of about 70 m. 
         [0054]    Referring to  FIG. 3 , a tip part  40  of a wind turbine rotor blade handling system is shown. The tip part  40  comprises a first rack  43  and a second rack  44 . Both racks  43 ,  44  comprise each a means of transportation  37 . The means of transportation  37  comprise two wheels each, which can be swivelled relative to the racks  43 ,  44 . The racks  43 ,  44  are positioned or set up vertically relative to the ground  38 . Alternatively, the racks  43 ,  44  may also be positioned on a common frame and the means of transportation  37 , e.g. comprising three wheels in total, are fixed to the common frame. 
         [0055]    Furthermore, the tip part  40  comprises a tip part frame ring  45 . The tip part frame ring  45  comprises a shape of a hollow circular cylinder. The tip part frame ring  45  is pivoted relative to the racks  43 ,  44  by means of a second pivot device  33 . The second pivot device  33  is a hinge. The second pivot device  33  allows a rotation of the tip part frame ring  45  about a second transversal rotational axis  34 . A rotation about 25° in both directions, thus 50° in total, is possible by the second pivot device  33 . 
         [0056]    A rotary device  30  is attached to the tip part frame ring  45 . By means of a chain, which is running inside the tip part frame ring  45 , the rotary device  30  enables a rotation of the tip part frame ring  45  up to 260°. The whole tip part frame ring  45  can be raised and lowered by the height adjustment means  35 . Two height adjustment means  35  are included, one at the first rack  43 , one at the second rack  44 . The height adjustment means  35  raise and lower the tip part frame ring  45  at the second pivot device  33 . They enable a vertical shift of up to 2 m. 
         [0057]    The tip part  40  further comprises a tip part frame  41 , which is made from steel. The tip part frame  41  is pivoted by a first pivot device  31 . The first pivot device  31  enables a rotation of the tip part frame  41  about a first transversal rotational axis  32 . A rotation of 25° in both directions, thus 50° in total, about the first transversal rotational axis  32  is possible. The first pivot device  31  comprises a hinge. 
         [0058]    The tip part frame  41  is connected to a tip part securing means  42 . The wind turbine rotor blade handling system shown in  FIG. 3  comprises four tip part securing means  42 . The tip part securing means  42  comprises a screw by which a wind turbine rotor blade  20  can be secured. The tip part securing means  42  comprises a cushion in order to protect a surface of the wind turbine rotor blade  20  from scratches or other damages. 
         [0059]    The wind turbine rotor blade  20  is secured to the wind turbine rotor blade handling system at its tip portion  22 . By means of the rotary device  30 , the wind turbine rotor blade  20  can be rotated about a rotor blade longitudinal rotational axis  23 . It can also be moved in vertical and horizontal direction by the first pivot device  31  and the second pivot device  33 . 
         [0060]    Referring to  FIG. 4 , a root portion  21  of a wind turbine rotor blade  20  and a root part  50  of a wind turbine rotor blade handling system is shown. The root portion  21  comprises a shape of a circular hollow cylinder that may have a diameter of 2.5 m. The root part  50  comprises a root supporting element  51  which supports the root portion  21 . The root supporting element  51  comprises a root part frame  52  which is connected to four rollers  53 . The rollers  53  comprise polyurethane and may have a shape of a circular cylinder with a diameter of 430 mm (millimetre) and a length of 400 mm. Each roller  53  is rotatably mounted about a roller longitudinal rotational axis  54 . The roller longitudinal rotational axis  54  is substantially parallel to a rotor blade longitudinal rotational axis  23 . During operation, i.e. when a rotary device  30  rotates the wind turbine rotor blade  20 , the root portion  21  is rotated counter clockwise, while the rollers  53  are rotated clockwise. To clarify, the rollers  53  are either locked to secure the rotor blade  20  or free rolling, so the rotor blade  20  can adapt to the rotation driven by the tip part  40 . 
         [0061]    Furthermore, the root supporting element  51  comprises three pairs of means of transportation  37  which comprise wheels. The whole root part  50  is located on a ground  38 . 
         [0062]    Referring to  FIG. 5 , a wind turbine rotor blade handling system comprising a tip part  40  and a root part  50  is shown. The wind turbine rotor blade handling system can be used for rotating a wind turbine rotor blade  20 . The wind turbine rotor blade  20  can, for example, be rotated about a rotor blade longitudinal rotational axis  23  and/or can be moved, i.e. transported in a direction which is substantially perpendicular to a gravitational force  36  of the wind turbine rotor blade  20 . The gravitational force  36  refers to a gravitational force  36  which is applied or is exerted on a centre of mass of the wind turbine rotor blade  20 . The wind turbine rotor blade handling system also comprises a means of transportation  37  comprising two pairs of wheels. Each wheel can be swivelled. 
         [0063]    While this disclosure has been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the present disclosure as set forth above are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention, as required by the following claims. The claims provide the scope of the coverage of the invention and should not be limited to the specific examples provided herein.