A WIND TURBINE TOWER ASSEMBLY DEVICE FOR MAKING A WIND TURBINE TOWER

Abstract

A wind turbine tower assembly device comprising a tower interface configured to be attached to a wind turbine tower during construction of the wind turbine tower, a nacelle interface for being attached to a part of a nacelle of a wind turbine and arranged to place the nacelle above a free end of a wind turbine tower which is attached to the tower interface; a lifting structure configured to move the nacelle interface relative to the tower interface to create a space between the free end of the wind turbine tower and the nacelle interface; a unit receiving structure configured to insert a tower unit into the space; and a tower assembly structure configured for joining the tower unit to the free end of the tower.

Claims

1. A wind turbine tower assembly device comprising: a tower interface configured to be attached to a wind turbine tower during construction of the wind turbine tower; a nacelle interface configured to be attached to a part of a nacelle of a wind turbine and arranged to place the nacelle above a free end of a wind turbine tower which is attached to the tower interface; a lifting structure configured to move the nacelle interface relative to the tower interface to create a space between the free end of the wind turbine tower and the nacelle interface; a unit receiving structure configured to insert a tower unit into the space; and a tower assembly structure configured for joining the tower unit to the free end of the tower.

2. The device according to claim 1, further comprising an encapsulation extending in the space and forming an enclosed area in the space.

3. The device according to claim 1, comprising a partition structure separating the enclosed area into an upper enclosed area and a lower enclosed area.

4. The device according to claim 1, wherein the tower assembly structure comprises a welding robot for automatic welding of a seam between the free end of the tower and the tower unit.

5. The device according to claim 1, comprising a surface treatment unit for surface treatment of the wind turbine tower.

6. The device according to claim 3, wherein the partition structure separates the welding robot from the surface treatment unit.

7. The device according to claim 1, further comprising a crawling structure configure to release the tower interface from the wind turbine tower, and reattach the tower interface at another location on the wind turbine tower.

8. The device according to claim 1, further comprising a compartment forming accommodation for objects.

9. A wind turbine nacelle comprising a main unit housing a main frame supporting a rotor assembly, the rotor assembly defining a rotation axis and the main unit being arranged to be mounted on a wind turbine tower via the main frame, the wind turbine further comprising at least one tower assembly device connected to the main unit and extending below the main frame, the tower assembly device comprising: a tower interface configured to be attached to the wind turbine tower during construction of the wind turbine tower, a lifting structure configured to lift the main unit relative to the tower interface to create a space between a free end of the tower and the main frame, a unit receiving structure configured to enter a tower unit into the space, and tower assembly structure configured for joining the tower unit to the free end of the tower.

10. The nacelle according to claim 9, wherein the tower assembly unit is releasable from the main unit.

11. A method of constructing a wind turbine generator at a construction site by use of a device according to claim 1, the method comprising: attaching the device between a main frame of a nacelle and the wind turbine tower; lifting the nacelle relative to the wind turbine tower to create a space between a free end of the wind turbine tower and the nacelle, inserting a tower unit into the space, and joining the tower unit to the free end of the tower.

12. The method according to claim 11, wherein the nacelle forms a main unit and at least one auxiliary unit, the main unit and the auxiliary unit being separate parts, and the main frame forms part of the main unit, and wherein the main unit and the auxiliary unit are assembled after the tower unit is joined to the free end of the tower.

13. The method according to claim 11, wherein the nacelle includes components being operative for transforming wind energy into electrical energy, and wherein at least one or more of these components are assembled after the tower unit is joined to the free end of the tower.

14. The method according to claim 11, comprising transporting blanks to the construction site, and forming, at the construction site, tower units for insertion into the space by bending the blanks and joining opposite free ends of the blanks.

Description

LIST OF DRAWINGS

[0032] In the following, embodiments of the disclosure will be described in further details with reference to the drawing in which:

[0033] FIG. 1 illustrates a wind turbine;

[0034] FIG. 2 illustrates an assembly device;

[0035] FIG. 3 illustrates a tower interface;

[0036] FIG. 4 illustrates a nacelle interface;

[0037] FIG. 5 illustrates an assembly device in operation;

[0038] FIG. 6 illustrates an assembly device;

[0039] FIGS. 7-8 illustrate an embodiment where the nacelle comprises a main unit and one or more auxiliary units;

[0040] FIGS. 9-16 illustrate details of a procedure to assemble the tower and subsequently the nacelle to reduce weight of the nacelle during tower construction.

DESCRIPTION OF EMBODIMENTS

[0041] The detailed description and specific examples, while indicating embodiments, are given by way of illustration only, since various changes and modifications within the spirit and scope of this disclosure will become apparent to those skilled in the art from this detailed description.

[0042] FIG. 1 illustrates a wind turbine 1 with a nacelle 2 mounted on a tower 3. A hub 4 carrying three rotor blades 5 is mounted at the nacelle 2. The nacelle supports a rotor-supporting assembly inside the nacelle. Typically, the rotor-supporting assembly comprises a rotor shaft connecting a gear arrangement and a generator to the hub 4.

[0043] The tower is typically assembled from a number of round sections of steel extending between flanges which are bolted to flanges of adjacent sections. Each section is often made from round units, also known as cans, which are welded to adjacent units. The cross section of the tower is often tapered in the direction from the bottom towards the top of the tower.

[0044] FIG. 2 illustrates a wind turbine tower assembly device 20 for making wind turbine towers. The device 20 comprises a chassis 21. In a bottom end 22 of the chassis 21, the device 20 forms a tower interface 23 which is illustrated in a cross section in FIG. 3. The tower interface 23 is arranged to be attached to a wind turbine tower during construction of the wind turbine tower 3 and comprises a number of claw elements 31 (shown in FIG. 3). The claw elements 31 are arranged to clamp about an outer surface 32 of the tower 33. Such claw elements may include power actuated, e.g. hydraulic or electric, actuators and friction pads being pressed against the outer surface 32 or a strand jack lifting system, e.g. forming a hollow cylinder, e.g. hydraulically actuated, and having steel cables passing through an open centre of the cylinder. The cables may pass through two clamps - one mounted to either end of the cylinder. This structure enables operation in a caterpillar’s walking manner and thereby allows climbing along the strands by the repeated procedure of releasing the clamp at one end, expanding the cylinder, clamping there, releasing the trailing end, contracting, and clamping the trailing end.

[0045] In an embodiment, the surface of the tower 33 has indentations or protrusions that provide an interface for the claw or clamp elements to attach to.

[0046] At a top end 24 of the chassis 21, the device 20 comprises a nacelle interface 25. The nacelle interface 25 is illustrated in further details in FIG. 4 and may e.g. comprise a flange 41 with bolt holes 42 arranged for bolting onto a flange of a yaw assembly of the nacelle 2. In that way, the nacelle interface 25 can be attached to a part of a nacelle 2 of the wind turbine 1 which is under construction.

[0047] The chassis 21 extends between the tower interface 23 and the nacelle interface 25, and the nacelle interface 25 is thereby arranged to place the nacelle above a free end of a wind turbine tower.

[0048] A lifting structure (not shown) is configured to move the nacelle interface relative to the tower interface to create a space 26 (illustrated by the bracket) between the free end of the wind turbine tower and the nacelle interface. The lifting structure may e.g. be comprised in the aforementioned strand jack lifting system.

[0049] The device is arranged to receive tower units 53 which are to be attached to the tower. The arrow 27 indicates a window in which a unit receiving structure can insert tower units into the space 26. The unit receiving structure may include the illustrated hoisting structure 28 by which the tower unit can be lifted from ground and inserted into the space. In the illustrated embodiment, the hoisting structure is constituted by a cantilever beam with a pulley structure mounted on a trolley 29. In the illustrated external position of the trolley, the tower units can be hoisted along an external tower surface until reaching a sideways window into the space. In this altitude, the trolley is moved as illustrated by the arrow 27 and the tower unit enters into the space.

[0050] The tower assembly structure includes an assembly structure, in this embodiment constituted by the welding assembly comprising one or more welding robots with welding guns 30 fixed to a rotating assembly allowing the welding robots to rotate about the outer surface of the tower. By this structure, the tower unit can be welded to the free end of the tower. Additionally or alternatively, the assembly structure may comprise any suitable structure for bolting, riveting, gluing or other ways of assembly.

[0051] In an embodiment the chassis 21 comprises a platform (not illustrated) from where personnel can perform welding manually and/or inspect the welding performed by the welding robots.

[0052] FIG. 5 illustrates a device 20 when in operation and being attached between a free end 51 of a tower and a part 52 of a nacelle. In the illustrated situation, the tower unit 53 is being hoisted from ground and will follow the path indicated by the arrows. The tower unit 53 is provided by the unit provider 54. The unit provider is a local manufacturing site configured to receive plane panels in the form of metal sheets and to curl up these sheets to form tubular elements with opposite free ends of the sheets being arranged against each other. The unit provider may be configured for assembling the free ends, e.g. by welding to form the units for the tower assembly.

[0053] In the space, the tower unit is lowered onto the free end of the tower, and an internal tower assembly structure joins the tower unit to the free end of the tower. Particularly, the tower assembly structure may include the welding assembly mentioned previously.

[0054] FIG. 6 illustrates an embodiment of the assembly device 20 including an encapsulation 61 forming an enclosed area in the space. The encapsulation 61 may be formed by a tarp or by more ridged wall structures, e.g. formed by a tubular steel wall. The encapsulation may form a shielding which is sufficiently closed to enable a controlled climate in the enclosed area, e.g. a controllable temperature or humidity. An environmental control system including a dehumidifier may be provided in the encapsulation.

[0055] In one embodiment, the encapsulation comprises air cushions or bellow structures 62 at the top end 24 and at the bottom end 23. These cushion or bellow structures are configured to expand into contact with an outer surface of the tower or tower unit and thereby provide a sealed enclosed area in which temperature and humidity can more easily be controlled.

[0056] A partition wall formed by the inflatable bellow 63 which can be inflated into contact with an outer surface of the tower may separate the enclosed area into an upper enclosed area 64 and a lower enclosed area 65.

[0057] The assembly structure, illustrated by the welding guns 30, may be housed in the upper enclosed area 64, and the lower enclosed area 65 may contain a surface treatment unit for treatment of the wind turbine tower. In one example, such a surface treatment unit includes abrasive cleaning equipment, painting equipment and paint curing equipment etc. In this way, a completely finished and surface treated interface between each tower unit may be created in the enclosed area.

[0058] One or more platforms (not shown) for personnel working in the device may be provided at appropriate locations to allow access to the tower structure as needed.

[0059] In FIG. 5, the assembly device is attached between a part of the nacelle, herein referred to as the main unit of the nacelle, and the free end of the tower. This is an alternative to lifting the entire nacelle during tower erection. According to this method, the nacelle is assembled after the tower is finished.

[0060] When the tower is finished, the main unit is fixed to the tower via a yaw assembly. Subsequently, the nacelle is completed by lifting further nacelle components and attaching them to the main unit. In one such embodiment, the nacelle is constituted by a main unit and one or more auxiliary units, each having e.g. the shape of a standard container for shipping.

[0061] The partly assembled nacelle can for example be used for equipment storage, storage of supplies, i.e. surface treatments, as a temporary workshop and/or accommodation for personnel during construction of the tower structure.

[0062] FIG. 7 illustrates hoisting of an auxiliary unit 71 up or down, e.g. if an auxiliary unit is used for a specific period of time during assembly of the wind turbine or during maintenance etc. The auxiliary unit 71 is hoisted by use of an internal crane 72 forming part of the main unit 52. Movement is essentially only in the vertical plane, illustrated by the arrow.

[0063] FIG. 8 illustrates the internal crane 72 in an enlarged view. The crane is attached to a roof part of the main unit. The internal crane can hoist the auxiliary unit in a vertical direction to a position where it is fixed to the main unit.

[0064] In accordance with the embodiment where the nacelle is constituted by a main unit and one or more auxiliary units, the assembly procedure may include that a first tower unit is installed on a foundation. The tower interface of an assembly device described herein is attached to the first tower unit, and a main unit of the nacelle is attached to the nacelle interface of the assembly device. The internal crane 72 on the main unit is used for hoisting tower units and the assembly device is used for assembling the tower units to the free end of the tower, and to lift the main unit to create space for the tower units to be inserted between the free end and the main unit. When the tower is finished, the crane 72 is used as indicated on FIGS. 7-8 to lift the auxiliary units and assemble them with the main unit to form the nacelle. In this way, the lifting structure of the tower assembly device will not need to lift the weight of a complete nacelle but only the weight of the main unit. Additionally, that main unit can be essentially empty or the heavy components, e.g. the drive train components, may be installed after the tower is finished. This will further reduce the required lifting capacity of the lifting structure of the tower assembly device.

[0065] One or more of the auxiliary units may contain separate cranes which, once the auxiliary unit is mounted on the main unit, can be used for lifting components from ground to the nacelle, e.g. for final assembly of the wind turbine or during maintenance.

[0066] FIGS. 9-10 illustrate an embodiment where the nacelle comprises a main unit and two auxiliary units 71. Each auxiliary unit contains a crane. Each crane 91 comprises a crane arm which can be lifted by the piston 92. The crane line 93 runs from a winch 94 around a pulley 95 placed at the rear end of the auxiliary unit 71. From the pulley, the crane line 93 extends to the top pulley 97 at the end of the crane arm and ends in a spreader which separates the hoisting point 98 into two hoisting points 99, 100 attached to the hub or to the blades for lifting and assembling the hub to the rotor supporting assembly in the main unit. The crane can comprise any known form of crane including any kind of support column or crane arm, and with or without articulation ability for the arm. The crane may include a jib, e.g. attached to the crane in a manner known from tower cranes, and the crane arm may be expandable, e.g. in a telescopic way.

[0067] FIG. 10 illustrates an embodiment where the cranes 91 in both auxiliary units 71 are used in combination for lifting the hub.

[0068] FIG. 11 illustrates a lifting method where two cranes 96 cooperate in the lifting of the hub 4 via a lifting bracket 111.

[0069] FIG. 12 illustrates a lifting method where two cranes 91 cooperate in the lifting of the hub 4 directly at one common lifting point, e.g. formed by a lifting lug 121 attached to the hub.

[0070] FIG. 13 illustrates a lifting method where two cranes 91 work in collaboration on blade lifting.

[0071] FIG. 14 illustrates an assembly method where components in the nacelle are inserted into the nacelle and installed after the nacelle is fitted on the tower. In this lifting method, two cranes 91 cooperate in lifting a gearbox, a generator, or similar component 141 of the drive train. In this procedure, the component is lifted from ground to the top of the tower and lifted sideways into the nacelle. In a maintenance situation, the opposite procedure may include lowering the component to the ground after they have been lifted out of the nacelle. The two cranes may be located in the same auxiliary unit, in this case a service unit on the left side of the main unit.

[0072] In any of the embodiments illustrated in FIGS. 7-14, the required lifting capacity of the lifting structure of the tower assembly unit can be reduced by assembling the nacelle after the tower is finished such that the lifting structure of the tower assembly unit only needs to lift the main unit including a crane which can be used both for lifting tower units during tower assembly and for lifting auxiliary units for completing the nacelle when the tower is made.

[0073] FIG. 15 illustrates the finished nacelle. The auxiliary unit 71 may e.g. facilitate accommodation of crew members working on the assembly of the wind turbine.

[0074] FIG. 16 illustrates an auxiliary unit accommodating a crane 91 for further assembly work.

[0075] In one embodiment, the crane 91 is used for lifting the tower unit 53 from the ground and thereby for assisting the unit receiving structure. In this embodiment, the unit receiving structure may be reduced simply to an opening into the space 26 through which opening, the crane 91 may lift the tower unit 53. In this embodiment, the wind turbine tower assembly device may comprise no lifting capacity for lifting the tower units.

[0076] In other embodiments, the crane 91 is used for supporting the lifting of the tower unit 53 from the ground, and the unit receiving structure may comprise complementary support, lifting or handling means configured for supporting entry of the tower unit into an opening into the space 26. In this procedure, the crane 91 may e.g. provide a vertical lift and support, lifting or handling means forming part of the unit receiving structure may e.g. provide horizontal movement of the tower unit into the space 26.