A SYSTEM AND METHOD FOR MANUFACTURING A WIND TURBINE BLADE

Abstract

The present invention relates to a manufacturing system (100) and methods for the manufacture of a wind turbine blade, the system comprising a frame body with a lower frame part (92a) and an upper frame part (92b). The upper frame part (92b) is detachably fastened on top of at least part of the lower frame part (92a) of the first frame body (92). A mould body (96) with a main mould part (96a) and a releasable tip mould part (96b) is supported by the frame body. Turning devices are fastened to the lower frame part (92a) for turning the frame body.

Claims

1. A manufacturing system (100) for the manufacture of a wind turbine blade, the system comprising: a first frame body (92) comprising a lower frame part (92a) and an upper frame part (92b), the upper frame part (92b) being detachably fastened on top of at least part of the lower frame part (92a) of the first frame body (92), a first mould body (96) supported by the first frame body (92), the first mould body comprising a first moulding surface (97) defining an outer part of a first wind turbine blade shell part, the first mould body comprising a main mould part (96a) and a releasable tip mould part (96b), wherein the releasable tip mould part is supported by the upper frame part (92b) of the first frame body (92), and one or more turning devices (95) for turning the first frame body (92), wherein the one or more turning devices are fastened to the lower frame part (92a) of the first frame body (92).

2. A manufacturing system (100) according to claim 1, the system further comprising: a second frame body (94) comprising a lower frame part (94a) and an upper frame part (94b), the upper frame part (94b) being detachably fastened on top of at least part of the lower frame part (94a) of the second frame body (94), a second mould body (98) supported by the second frame body (94), the second mould body comprising a second moulding surface (99) defining an outer part of a second wind turbine blade shell part, the second mould body comprising a main mould part and a releasable tip mould part, wherein the releasable tip mould part is supported by the upper frame part (94b) of the second frame body (94), and wherein the one or more turning devices are arranged for turning the first frame body (92) relative to the second frame body (94).

3. A manufacturing system (100) according to claim 1, wherein the upper frame part (92b) has a length of between 2-35% of the length of the lower frame part (92a) of the respective frame body.

4. A manufacturing system (100) according to claim 1, wherein the upper frame part (92b) has a length of between 2-40 meters and wherein the lower frame part (92a) has a length of 40-120 meters.

5. A manufacturing system (100) according to claim 1, wherein the first and/or the second frame body (94) each comprise at least two interchangeable upper frame parts (92b, 92b′) having different lengths.

6. A manufacturing system (100) according to claim 1, wherein the first and/or the second mould body each comprise at least two interchangeable tip mould parts having different lengths.

7. A manufacturing system (100) according to claim 1, wherein each lower frame part (92a) extends over the entire length of its respective mould body, and/or wherein the lower frame part (92a) of the second frame body (94) is fastened to a ground surface.

8. A manufacturing system (100) according to claim 1, wherein each main mould part is supported by its respective lower frame part (92a).

9. A manufacturing system (100) according to claim 1, wherein each frame body forms an open-framed structure such as an open-framed lattice or truss structure.

10. A manufacturing system (100) according to claim 1, wherein each frame body comprises fastening elements for detachably fastening the upper frame part (92b) to the respective lower frame part (92a), e.g. wherein the position of the fastening elements on the lower frame part (92a) is variable in the length direction and/or in the width direction of the lower frame part (92a).

11. A method of manufacturing a wind turbine blade using the manufacturing system (100) of claim 1, the method comprising the steps of: arranging one or more layers of fibre material on the first and second moulding surfaces, injecting the one or more layers of fibre material with a curable resin, curing the resin to form to form respective first and second blade shell parts, closing the first and second blade shell parts to form a closed wind turbine blade shell using the one or more turning devices for turning the first frame body (92) relative to the second frame body (94), and bonding said first and second blade shell parts to form a wind turbine blade.

12. A method of manufacturing a wind turbine blade using the manufacturing system (100) of claim 1, the method comprising the steps of: forming a cured first blade shell part and transferring the first blade shell part to the first mould body, forming a cured second blade shell part and transferring the second blade shell part to the second mould body, performing at least one post-moulding operation on the first and/or second blade shell part, closing the first and second blade shell parts to form a closed wind turbine blade shell using the one or more turning devices for turning the first frame body (92) relative to the second frame body (94) and, bonding said first and second blade shell parts to form a wind turbine blade.

13. A method of manufacturing at least two wind turbine blades having different sizes, using the manufacturing system (100) of claim 1, the method comprising the steps of manufacturing a first wind turbine blade, comprising providing respective upper frame parts (92b) and releasable tip mould parts (96b) for forming respective first and second moulding surfaces having a first size, forming respective first and second blade shell parts on the respective first and second moulding surfaces having the first size, or transferring respective first and second blade shell parts to the respective first and second moulding surfaces having the first size, closing the first and second blade shell parts to form a closed wind turbine blade shell using the one or more turning devices for turning the first frame body (92) relative to the second frame body (94), and bonding said first and second blade shell parts to form the first wind turbine blade, manufacturing a second wind turbine blade having a second size, comprising providing respective upper frame parts (92b′) and releasable tip mould parts (96b′) for forming respective first and second moulding surfaces having a second size, forming respective first and second blade shell parts on the respective first and second moulding surfaces having the second size, or transferring respective first and second blade shell parts to the respective first and second moulding surfaces having the second size, closing the first and second blade shell parts to form a closed wind turbine blade shell using the one or more turning devices for turning the first frame body (92) relative to the second frame body (94), and bonding said first and second blade shell parts to form the second wind turbine blade.

14. A method according to claim 11, wherein the lower frame part (92a) of the second frame body (94) remains fastened to a ground surface while carrying out said steps.

15. A wind turbine blade manufactured according to the method according to claim 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0073] Certain embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0074] FIG. 1 shows a wind turbine;

[0075] FIG. 2 shows a schematic view of a wind turbine blade;

[0076] FIG. 3 shows a schematic view of an airfoil profile of the blade of FIG. 2;

[0077] FIG. 4 is a perspective view of a manufacturing system according to the present invention

[0078] FIG. 5 is a schematic cross-sectional view along the line A-A′ in FIG. 4,

[0079] FIG. 6 is a partial top view of a frame body according to the present invention,

[0080] FIG. 7 is a partial side view of a frame body according to the present invention, and

[0081] FIG. 8 is a schematic perspective view of a manufacturing system according to the present invention.

[0082] FIG. 1 illustrates a conventional modern upwind wind turbine according to the so-called “Danish concept” with a tower 4, a nacelle 6 and a rotor with a substantially horizontal rotor shaft. The rotor includes a hub 8 and three blades 10 extending radially from the hub 8, each having a blade root 16 nearest the hub and a blade tip 14 furthest from the hub 8. The rotor has a radius denoted R. While a three-bladed upwind wind turbine design is presented here, it will be understood that the invention may equally apply to blades of other wind turbine designs, e.g. two-bladed, downwind, etc.

[0083] FIG. 2 shows a schematic view of a first embodiment of a wind turbine blade 10 according to the invention. The wind turbine blade 10 has the shape of a conventional wind turbine blade and comprises a root region 30 closest to the hub, a profiled or an airfoil region 34 furthest away from the hub and a transition region 32 between the root region 30 and the airfoil region 34. The blade 10 comprises a leading edge 18 facing the direction of rotation of the blade 10, when the blade is mounted on the hub, and a trailing edge 20 facing the opposite direction of the leading edge 18.

[0084] The airfoil region 34 (also called the profiled region) has an ideal or almost ideal blade shape with respect to generating lift, whereas the root region 30 due to structural considerations has a substantially circular or elliptical cross-section, which for instance makes it easier and safer to mount the blade 10 to the hub. The diameter (or the chord) of the root region 30 may be constant along the entire root area 30. The transition region 32 has a transitional profile gradually changing from the circular or elliptical shape of the root region 30 to the airfoil profile of the airfoil region 34. The chord length of the transition region 32 typically increases with increasing distance r from the hub. The airfoil region 34 has an airfoil profile with a chord extending between the leading edge 18 and the trailing edge 20 of the blade 10. The width of the chord decreases with increasing distance r from the hub.

[0085] A shoulder 40 of the blade 10 is defined as the position, where the blade 10 has its largest chord length. The shoulder 40 is typically provided at the boundary between the transition region 32 and the airfoil region 34.

[0086] It should be noted that the chords of different sections of the blade normally do not lie in a common plane, since the blade may be twisted and/or curved (i.e. pre-bent), thus providing the chord plane with a correspondingly twisted and/or curved course, this being most often the case in order to compensate for the local velocity of the blade being dependent on the radius from the hub.

[0087] FIG. 3 shows a schematic view of an airfoil profile 50 of a typical blade of a wind turbine depicted with the various parameters, which are typically used to define the geometrical shape of an airfoil. The airfoil profile 50 has a pressure side 52 and a suction side 54, which during use—i.e. during rotation of the rotor—normally face towards the windward (or upwind) side and the leeward (or downwind) side, respectively. The airfoil 50 has a chord 60 with a chord length c extending between a leading edge 56 and a trailing edge 58 of the blade. The airfoil 50 has a thickness t, which is defined as the distance between the pressure side 52 and the suction side 54. The thickness t of the airfoil varies along the chord 60. The deviation from a symmetrical profile is given by a camber line 62, which is a median line through the airfoil profile 50. The median line can be found by drawing inscribed circles from the leading edge 56 to the trailing edge 58. The median line follows the centres of these inscribed circles and the deviation or distance from the chord 60 is called the camber f. The asymmetry can also be defined by use of parameters called the upper camber and lower camber, which are defined as the distances from the chord 60 and the suction side 54 and pressure side 52, respectively.

[0088] Airfoil profiles are often characterised by the following parameters: the chord length c, the maximum camber f, the position df of the maximum camber f, the maximum airfoil thickness t, which is the largest diameter of the inscribed circles along the median camber line 62, the position dt of the maximum thickness t, and a nose radius (not shown). These parameters are typically defined as ratios to the chord length c.

[0089] The wind turbine blades may further comprise pre-bent blades, wherein the body of the blade is designed having a bend or curve, preferably in the direction of the pressure side of the blade. Pre-bent blades are designed to flex during operation of the wind turbine, such that the blades straighten under the effect of optimum wind speed at the wind turbine. Such a pre-bent blade will provide improved performance during wind turbine operation, resulting in numerous advantages, e.g. tower clearance, swept area, blade weight, etc.

[0090] One way of constructing a wind turbine blade 10 comprises forming the blade 10 as two separate shell pieces—a first piece which substantially forms the pressure or upwind side 52 of the blade 10, and a second piece which substantially forms the suction or downwind side 54 of the blade 10. Such shell pieces are normally formed in separate open blade moulds conforming to the aerodynamic shapes of the respective sides, and are subsequently joined together by closing the blade moulds to form a wind turbine blade 10.

[0091] An embodiment of a manufacturing system for the manufacture of a wind turbine blade according to the invention is illustrated in FIG. 4. The illustrated system comprises a conventional moulding station 70 and a manufacturing system 90 of the present invention. The blade moulding station 70 comprises a set of first and second blade shell moulds 72, 74. The blade moulds 72, 74 comprise respective first and second internal surfaces 76, 78 which are arranged to produce first and second cured blade shell parts having an aerodynamic profile substantially corresponding to respective upwind (or pressure side) and downwind (or suction side) halves of a wind turbine blade.

[0092] A lay-up operation is performed at the blade moulding station 70, wherein a plurality of layers of a preferably fibre-based composite material are applied to the internal surfaces 76, 78 of the blade moulds 72, 74. The fibre layers are applied to conform to the mould shape, and may be arranged at various thicknesses or densities dependent on the structural requirements of the wind turbine blade to be manufactured.

[0093] In the embodiment shown in FIG. 5, the blade moulding station 70 is provided with an automatic fibre lay-up apparatus 80, which allows for machine-controlled lay-up of the layers of fibre-based material in the blade moulds 72, 74. The automatic fibre lay-up apparatus comprises at least one fibre applicator device suspended on a moveable gantry provided above the blade moulds 72, 74, the at least one fibre applicator device operable to move along the length of the blade moulds 72, 74 to apply fibre layers, e.g. fibre tape, to the internal surfaces 76, 78 of the blade moulds 72, 74.

[0094] However, it will be understood that the manufacturing system of the invention may be implemented using any suitable lay-up mechanism, e.g. hand lay-up. Furthermore, the lay-up operation may comprise the use of pultruded elements or pre-pregs of composite material within the blade moulds, either as an alternative to or in addition to the layers of fibre-based material.

[0095] Once sufficient layers of the fibre-based material have been applied to the surfaces of the moulds 72, 74, a curing operation is then performed to cure the fibre layers to a relatively hardened state. In one embodiment, this may comprise applying a cover or vacuum bag over the fibre layers to form a container, and subsequently applying a vacuum pressure to the interior of the container defined by the vacuum bag and the surface of the blade mould 72, 74.

[0096] A curing resin is then infused or injected into the interior of the container, the resin spreading throughout the fibre layers by the action of the vacuum pressure. The resin is then allowed to cure and accordingly harden and join the layers of fibre-based material into a cured blade element, preferably comprising a cavity for later integration of a reinforced section (not shown); the cured blade element having a structural profile corresponding to the shape of the surface of the blade moulds 72, 74.

[0097] The term “cured blade part” is used herein to refer to blade parts which have been substantially cured by the curing operation, preferably to a level where the blade parts can be handled without undergoing significant deformation of the shell structure. The duration of the curing operation performed will depend on the type of curing resin used in the manufacture of the blade shell parts, but may be of the order of 2-3 hours using standard resins. However, it will be understood that the blade parts themselves may continue to undergo a curing process within the body of the blade parts for several hours after the denoted curing operation.

[0098] Accordingly, once the blade parts have substantially cured, the associated cover or vacuum bag may be removed, and the cured blade parts can be demoulded from the blade moulds 72, 74. To demould the blade parts, any manufacturing equipment which may be provided above the blade moulds 72, 74, e.g. automatic fibre applicator device 80, may be removed, and a lifting apparatus (not shown) may be positioned above the blade parts contained in the blade moulds 72, 74. The lifting apparatus is operable to lift the cured blade parts out of the blade moulds 72, 74, and to transfer the cured blade parts to the manufacturing system 90, where reinforcing and optionally post-moulding operations may be performed.

[0099] It will be understood that the transferring operation may be performed using any suitable lifting apparatus for the transferral of a wind turbine blade elements, e.g. a vacuum lifting device, a crane, a manual lifting operation, etc.

[0100] The manufacturing system 90 comprises a first frame body 92 and a second frame body 94 each comprising a mould body 96, 98 supported by respective support frame bodies. Each cured blade part can be arranged in its mould body for forming a reinforced section on the cured blade part of each blade shell or for carrying out other post-moulding operations. Forming of the reinforced section will typically include the lay-up of additional fibre material on the cured blade element, preferably in cavity prepared therein, followed by vacuum-assisted resin infusion and curing.

[0101] The first and second frame bodies 92, 94 are arranged in a parallel longitudinal relationship, the first frame body 92 being coupled to the second frame body 94 via a plurality of hinging mechanisms 95. The first frame body 92 is arranged to be hinged relative to the second frame body 94, such that the first frame body 92 is positioned above the second frame body 94 to form a closed arrangement. The first frame body 92 may also be translationally movable relative to the second frame body 94 when in the closed position, to correct the alignment between the first and second frame bodies 92, 94. The first frame body 92 may be moveable along the horizontal and/or vertical axis with respect to the second frame body 94.

[0102] Examples of post-moulding operations which can be performed at the post-moulding station 90 on the blade shells can include, but are not limited to: a blade shell repair operation, involving a repair of any minor defects in a cured blade shell; a blade shell cutting or grinding operation, wherein a portion of a surface of the cured blade shell can be cut away or ground to present a relatively smooth profile; a blade root flange coupling operation, wherein a pair of blade root flanges which are provided on first and second blade shells are coupled together to form a single integral blade root flange; a gluing operation, wherein an adhesive is applied to a surface of a blade shell to bond components or blade shells together; a coating operation, wherein an external surface of a blade shell is coated with a coating layer, e.g. a gel coat or suitable erosion resistant material; a laminate installation operation, wherein a main laminate or other element of the interior of a wind turbine blade may be fixed to an internal surface of one of the blade shells for positioning in the interior of a wind turbine blade; an overlamination operation; installation of internal blade components, e.g. load or deflection monitoring sensors, lightning protection systems, etc.; a survey of blade shell geometry; a secondary curing operation in, for example, an oven; or any other suitable manufacturing or assembly operations.

[0103] While the embodiment shown in FIG. 4 illustrates a manufacturing system with a separate moulding station and a manufacturing system according to the present invention, both the moulding and the post-moulding operations can be carried out in the mould bodies 96, 98 of the manufacturing system 90. Alternatively, the moulding station 70 could also comprise first and second frame bodies as discussed above for the manufacturing system of the present invention.

[0104] FIG. 5 shows a schematic cross-sectional view of one embodiment of a manufacturing system 100 according to the present invention. The manufacturing system 100 comprises a first frame body 92 and a second frame body 94. The first frame body 92 comprises a lower frame part 92a and an upper frame part 92b, which is detachably fastened to the lower frame part 92a. Likewise, the second frame body 94 comprises a lower frame part 94a and an upper frame part 94b, which is detachably fastened to the lower frame part 94a. The upper frame parts 92b and 94b each support a first mould body 96 and a second mould body 98, respectively. Each mould body 96, 98 comprises a moulding surface 97, 99 defining an outer part of respective wind turbine blade shell parts, i.e. a pressure side shell and a suction side shell.

[0105] Fibre-reinforcement material as well as possible core material may be arranged on the moulding surfaces of the mould bodies 96, 98, after which a curable resin may be infused into mould cavities formed by the mould bodies 96, 98 which is subsequently cured. Alternatively, the mould bodies 96, 98 of FIG. 5 may receive already cured shell parts for one or more post-moulding operations being carried out in the manufacturing system.

[0106] In a next step, the cured and optionally further treated wind turbine blade shell parts may be adhered to each other. This may be carried out by applying glue to the leading edge and trailing edge (and along a not shown glue flange), after which the first mould body 96 along with the first wind turbine blade shell part is turned over and aligned with the second mould body 98 and second wind turbine blade shell part, such that the two wind turbine blade shell parts are adhered to each other along the leading edge and trailing edge.

[0107] The two mould bodies 96, 98 are arranged in parallel to each other. To turn the first mould body 98 over, a plurality of turning devices 95 are arranged along the longitudinal direction of the two mould bodies 96, 98. The turning devices 95 each comprise a stationary base part 102 and a rotational part 104, which is rotationally movable relative to the base part 102 about a rotation axis 16. The base part 102 is attached or at least fixedly arranged with respect to the lower frame part 94a of the second frame body 94. The rotational part 104 is attached to the lower frame part 92a of the first frame body 92, such that the first frame body 92 may be turned relative to the second frame body 94. The base part 102 and the rotational part 104 are preferably detachably coupled to the second frame body 94 and the first frame body 92, respectively.

[0108] One embodiment of a frame body according to the present invention is illustrated in the partial top view of FIG. 6 and the partial side view of FIG. 7. As seen in FIG. 6, the frame body comprises a set of opposing side rails 112a, 112b extending longitudinally between a tip end 110 and an opposing root end (not shown due to cut-off). A plurality of support elements 114 of having different spatial orientations form an open-framed structure such as an open-framed lattice or truss structure.

[0109] As seen in FIG. 7, an upper frame part 92b is detachably fastened to a lower frame part 92a. The frame body 92 also comprises height adjustment blocks 122, length adjustment elements 120, and width adjustment elements 117 for accommodating for different sizes of upper frame parts 92b. In addition, the frame body 92 comprises first fastening elements 116 and second fastening elements 118 for fixing the upper frame part 92b to the lower frame part 92a in the length and width direction, respectively. The lower frame part 92a illustrated in FIG. 7 has a stepped height profile with a first height h1 along a first section and a second, lower height h2 along a second section of its length. The upper frame part 92b is detachably fastened on top of said second section of the lower frame part 92a. The length Le of the lower frame part and the extent of the first section S1 and the second section S2 are illustrated with the dashed lines of FIG. 8B.

[0110] The schematic perspective view of FIGS. 8A, 8B and 8C illustrates different parts of a manufacturing system according to the present invention for manufacturing blade shell parts of two alternative sizes. A frame body 92 comprises a lower frame part 92a and an upper frame part 92b, the upper frame part 92b being detachably fastened on top of part of the lower frame part 92a. The respective upper frame part 92b is different in the two embodiments shown in respective FIGS. 8A and 8B, while the lower frame part 92 is the same. As described above, the frame parts 92a, 92b, will usually comprise several support elements such as bars or rods with different spatial orientation (not shown).

[0111] A mould body 96 is supported by the first frame body 92, the mould body 96 comprising a moulding surface 97 defining an outer part of a wind turbine blade shell part, such as a downwind shell half or an upwind shell half. The mould body 96 comprises a main mould part 96a and an exchangeable tip mould part 96b, wherein the exchangeable tip mould part 96b is supported by the upper frame part 92b. As seen in FIG. 8B, the tip mould part 96b′ can be exchanged together with its supporting upper frame part 92b′ in an easy and quick way if a blade shell of a different size and/or shape is to be produced.

[0112] FIG. 8C illustrates a third arrangement in which a longer tip mould part 96b″ is provided together with its supporting upper frame part 92b″ for providing a longer moulding surface. Thus, the embodiment of the manufacturing system in FIG. 8 enables the efficient manufacturing of blade shell parts of three different sizes.

[0113] The invention is not limited to the embodiment described herein, and may be modified or adapted without departing from the scope of the present invention.