Patent ID: 12241451

DETAILED DESCRIPTION

FIG.1shows a wind turbine rotor blade20during an installation procedure. The rotor blade20is being hoisted to the level of the hub21of an offshore wind turbine, so that its root end20R can be attached to the hub21. A handling arrangement1holds the rotor blade20as shown, i.e. with its airfoil20A in an essentially horizontal orientation, and this handling arrangement1is hoisted by a crane (only partially shown), for example a crane on an installation vessel in the case of an offshore wind turbine.

Each rotor blade20of the wind turbine2has an arrangement of add-ons200on its suction side20S, as shown in the exemplary embodiment illustrated byFIG.2. The add-ons200—in this case vortex generators—are arranged essentially parallel to the leading edge LE and serve to improve the aerodynamic performance of the rotor blades20. Of course, the rotor blade may be equipped with other further arrangements of add-ons, and may also have add-ons on its pressure side.

During the lifting procedure, the rotor blade can be held with its suction side20S facing downwards. This is to avoid unfavorably large lift forces that would be caused by airflow over the rotor blade20, as will be known to the skilled person, especially if the leading edge LE faces into the wind. However, as shown inFIG.3, a favored location for add-ons200is in line with a structurally reinforcing web20W arranged in the rotor blade interior. This position is therefore also the most suitable location for placing a pad of a handling arrangement. Conventionally, the solution has been to omit a sufficient number of add-ons to leave a gap for a lifting apparatus pad (with an associated reduction in aerodynamic efficiency), or to construct a pad for placement to one or both sides of the add-ons (thereby risking damage to the rotor blade).

The inventive handling arrangement1is constructed to be able to grasp the rotor blade20without damaging any of the add-ons200. This is illustrated inFIG.4, which shows the handling arrangement1in place about a rotor blade20, which is oriented so that its suction side20S faces downward. In this exemplary embodiment, the handling arrangement1comprises a frame assembly11realized to fit about the airfoil20A of the rotor blade20, and to clamp the rotor blade20between pads10,11P in a region near the center of mass of the rotor blade20. Here, the pads10,11P are essentially in line with the structurally reinforcing web20W in the rotor blade interior. The diagram shows a protective cup10arranged to fit between the frame assembly11and the airfoil surface of the downward-facing suction side20S, and a further pad11P arranged to fit between the frame assembly11and the airfoil surface of the upward-facing pressure side20P. The protective cup10has a rigid housing10H that is shaped to define a volume or cavity10C which encloses or surrounds one or more add-ons200protruding from the airfoil surface. The cavity10C defined by the housing10H and the airfoil surface is filled with a non-compressible load-bearing material M. A seal10S arranged about the perimeter of the housing10H ensures that the load-bearing material M cannot escape during the lifting procedure. The frame assembly11of the handling arrangement1is connected by means of an outer structure12and lifting eyelet13to a hoisting apparatus such as a crane. The frame assembly11can be opened and closed by means of remote control, as will be known to the skilled person.

FIG.5shows a protective cup10in one possible embodiment of the invention. Here, the protective cup10is filled with the chosen load-bearing material M before being pressed against the airfoil surface20S. The diagram shows the rotor blade20arranged so that a surface with add-ons200is arranged to face downwards. In this exemplary embodiment, the seal10S is realized as an inflatable chamber or tube which, when inflated, will conform to the surface of the rotor blade.

FIG.6shows a further possible embodiment of the invention. The rotor blade20is arranged so that a surface carrying add-ons200faces upwards. A protective cup10mounted on the frame of the handling arrangement1is arranged in place about a group of add-ons200. The frame assembly is clamped about the rotor blade20so that pressure is applied to press the seal10S against the rotor blade surface. In this exemplary embodiment, the protective cup10is equipped with a port10P through which the load-bearing material M can be introduced to fill the cavity10C. In this exemplary embodiment, the seal10S is realised as a flexible lip which, when pressed against the rotor blade, will conform to the surface of the rotor blade. In this case, the seal10S faces inwards, so that the filler M will press against the seal10S, causing it to make optimal contact with the rotor blade surface during the entire handling procedure, thereby increasing the effectiveness of the seal10S. The load-bearing material M can be sand, water, a gel, a colloid, etc. For example, sand can be filled into the protective cup10. With sand (or any comparable granulate material) as a filler, the protruding add-ons can bury into the granulate. When the cover is pressed against the airfoil surface, the granulate contacts the rotor blade surface. The grains of sand are pressed together, making contact by virtue of their many surfaces, and can therefore very effectively transfer the downward load to the frame assembly when the rotor blade is being lifted, while the add-ons are not subject to any loading and are optimally protected from damage. The filler can simply be dry sand, or a quantity of water can be added to form a colloid filler and to further improve the effectiveness of load transfer within the cup.

A combination of insoluble granulate and water can advantageously reduce the lateral forces on the seal, and can be the preferred choice of filler in the case of relatively robust add-ons. More vulnerable add-ons may benefit from a dry granulate or other filler such as a gel or colloid.

Alternatively, as explained above, the load-bearing material M can be any particulate or granular material that is essentially non-compressible and which will not adhere to the rotor blade, i.e. a material that will detach from the rotor blade20without any assistance. For example, a water-based gel may simply slide off the rotor blade20or may be washed off by rain. The materials mentioned above are non-polluting and do not present any environmental risk.

Of course, the features of the embodiments described above—i.e. the choice of seal, the choice of filler, etc. can be combined or exchanged in any reasonable manner.

FIG.7shows a perspective view of a protective cup10as described above. The diagram shows the housing10H and the seal10S about the perimeter of the housing10H. A group of vortex generators200is indicated by dotted lines, and the diagram shows how these will be safely enclosed by the filler M when the cup10is put into place about the vortex generators200. The load-bearing material M will be prevented from escaping from the cup10when the seal10S is pressed against the rotor blade surface.

FIG.8shows a further possible embodiment of the invention. Here, the rotor blade20has add-ons200on its suction side20S and also on its pressure side20P. The handling arrangement1is equipped with appropriately arranged protective cups10for placement over the add-ons on the suction side20S and also on the pressure side20P, so that the add-ons200remain undamaged during handling of the rotor blade. In this embodiment, two protective covers10are provided for each of the suction side20S and the pressure side20P.

Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention. For example, the filler material can be collected after completion of a handling maneuver, for example by extracting the material through a port and conveying it to a storage container.

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