Co-perfusion of wind turbine blade glued flanges

Abstract

A method of manufacturing a wind turbine blade shell comprising a first wind turbine blade shell portion and a second wind turbine blade shell portion is provided. The method comprises: providing a blade mold (50) for forming a first blade shell portion; arranging the fiber reinforcement material (74) in the blade mold (50); disposing a first set of one or more fixing devices (61, 71) at corresponding one or more fixing device locations along a first edge (51) of the blade mold; arranging the first prefabricated gluing flange (81) in the blade mould using the first set of fixing means as a position reference; arranging the vacuum bag above the blade mold so as to form a mold cavity in which the fibre-reinforced material, the first gluing flange (81) and the first set of fixing means (61, 71) are contained; extracting air from the mold cavity; providing a resin into the mold cavity; and curing the resin. A corresponding system is provided.

Description

Technical Field

[0001] The present invention relates to a method and a system for manufacturing a composite wind turbine blade shell. Background Art

[0002] Wind turbine blades made of fiber reinforced polymers, and in particular aerodynamic wind turbine blade shells, are typically manufactured using two molds. A first blade shell portion (such as a suction side portion) and a second blade shell portion (such as a pressure side portion) of the blade are manufactured separately by arranging glass fiber mats and / or other reinforcing materials (such as carbon fiber materials and fiber pultrusions) in each of the two molds. After manufacturing the blade shell portions, the two portions are typically glued together by means of an internal glue flange. Before lowering the second blade shell portion for assembly with the first blade shell portion, an adhesive is applied to the glue flange and / or to the inner face of the second blade shell portion. In addition, before the first blade shell portion is glued to the second blade shell portion, one, two or more reinforcing profiles (such as shear webs or beams) are typically attached to the inner side of the first blade shell portion. It is known that the glued joints that hold the different portions together in wind turbine blades represent to some extent weak points in the structural integrity of the wind turbine blades. As wind turbine blades increase in size, it becomes increasingly more complex to manufacture wind turbine blades with the required structural integrity, including the integrity of the glued joints between blade shell parts.

[0003] Therefore, there is a need to ensure that the glued joint provided by the internal glue flange provides as much structural strength to the blade as possible. Summary of the invention

[0004] The above-mentioned problems are alleviated by the embodiments disclosed herein.

[0005] In a first aspect, the invention provides a method of manufacturing a wind turbine blade shell comprising a first wind turbine blade shell part and a second wind turbine blade shell part. The method comprises: - providing a blade mould for forming a first blade shell part, - Arrange the fiber reinforcement in the blade mold, - providing a first set of one or more fixing means at corresponding one or more fixing means locations along a first edge of the blade mould, - arranging the first prefabricated glue flange in the blade mould using the first set of fixing means as position reference, whereby the first glue flange is arranged in a first position relative to the blade mould, - placing a vacuum bag over the blade mould so as to form a mould cavity, wherein the fibre reinforcement material, the first glue flange and the first set of fixing means are contained within the mould cavity, - extract air from the mold cavity, - providing resin into the mold cavity, and - Curing the resin, thereby forming the first blade shell part.

[0006] The method according to the first aspect allows a relatively easy preparation of a mould having a fibre reinforcement and a gluing flange, while ensuring that the gluing flange is correctly positioned before being co-infused with the fibre reinforcement when air is evacuated in preparation for providing (infusing) the resin into the mould cavity. The first set of fixtures is adapted to limit the movement of the first gluing flange during the step of evacuating air, acting as a stop during the step of evacuating air from the mould cavity, thereby providing a position reference. The restriction (constraint) of the movement of the first gluing flange results in the first gluing flange being correctly positioned in a well-defined final position after the step of evacuating air from the mould cavity. Due to the correct positioning of the first gluing flange, the strength provided by the first gluing flange to the blade shell is optimised. Furthermore, despite the inclusion of the first set of fixtures in the mould cavity, the arrangement of the vacuum bag is hardly affected compared to the case where the gluing flange is not co-infused during the manufacture of the first blade shell part in the mould. The present invention exploits the fact that after the manufacture of the first blade shell part, the upper part of the first gluing flange (the free part of the first gluing flange) can be further prepared, such as by cleaning or grinding. Hence, before assembling the two blade shell parts, the resin or other substance on the upper part of the first glue flange may be removed.The first blade shell part and the second blade shell part may for example be the suction side and the pressure side of a wind turbine blade shell.

[0007] The number and shape of the first set of fixing means are selected so that the first glue flange does not change shape significantly during air extraction, as this would cause the first glue flange to impose permanent strains on other components of the blade shell after manufacturing. The fixing means are typically location specific and preferably follow the local contour of the first glue flange. This increases the area of ​​the first glue flange in contact with the fixing means, which results in a minimum local pressure on the first glue flange, avoiding strains in the first glue flange.

[0008] In some embodiments, the first glue flange is shaped such that when the first blade shell part and the second blade shell part are assembled to form the blade shell, glue applied to the first side of the first glue flange will engage with the inner surface of the second blade shell part and thereby provide a bond between the first blade shell part and the second blade shell part. This bonds the first blade shell part to the second blade shell part. Preferably, all glue provided over the entire first surface engages with the inner surface of the second blade shell part. This provides the highest achievable bond strength.

[0009] In some embodiments, prior to the step of evacuating air from the mould cavity, the first glue flange is held in a first position against the first set of fixtures using at least one or more glue flange attachment means, such as an adhesive, such as a pressure sensitive adhesive, that attaches the first glue flange to the first set of fixtures. In some embodiments, the adhesive is attached to the first glue flange and each of the fixtures, for example wrapped around an upper edge of the first glue flange and an upper edge of each fixture, thereby temporarily holding the first glue flange to the first set of fixtures. The adhesive may also be provided in the form of a fibrous material, such as a fibrous mat material, which is glued to the fixtures, wrapped around an upper edge of the first glue flange and an upper edge of each fixture, and glued to the first glue flange.

[0010] Other ways of temporarily holding the first glue flange may be used. For example, the first glue flange may be temporarily held by a fixing device using a wire (such as a metal wire). Alternatively or in addition, a fiber material (such as a fiber mat) may be glued to the first glue flange on a surface of the first glue flange that faces the fiber reinforcement material in the mold, and the fiber mat may be attached to the first edge of the first blade mold indirectly (such as sewing to other fiber reinforcement material arranged on the first mold edge) or directly (such as fixing directly to the first mold edge). This method has the advantage of providing a robust hold on the first glue flange. A portion of the fiber mat becomes integrally integrated in the first blade shell part. If a wire or a pressure sensitive adhesive is used to hold the first glue flange, these elements must be removed after the blade shell part is manufactured.

[0011] In some embodiments, the fiber reinforcement material and the first glue flange are arranged so that during the step of evacuating air from the mold cavity, the first glue flange moves from the first position to the final position at least partially due to the force applied by the vacuum bag to the first glue flange during the step of evacuating air from the mold cavity, and / or at least partially due to the compression of the fiber reinforcement material in the mold cavity during the step of evacuating air from the mold cavity. Such embodiments are even more advantageous because they allow greater flexibility when arranging the fiber reinforcement material and the first glue flange in the blade mold. The first set of fixing means limits the movement of the glue flange so that the movement cannot continue beyond the final position. In other words, when the glue flange is in the final position, the first set of fixing means prevents further movement of the glue flange.

[0012] In some embodiments, the first set of fixing means comprises a respective glue flange stopper facing the first glue flange and defining a position reference for the first glue flange. Preferably, the glue flange stopper is shaped to follow the contour of the first glue flange at the position where the glue flange stopper contacts the first glue flange. In particular, if during the step of extracting air from the mould cavity the first glue flange is moved from a first position to a final position different from the first position, the glue flange stopper is preferably adapted to follow the contour of the first glue flange when the glue flange is in the final position. This at least reduces strains that may occur in the event that the first glue flange flexes due to pressure from the vacuum bag. The latter may cause the first glue flange to continuously exert a force inside the blade shell, which may shorten the life of the blade shell.

[0013] In some embodiments, a peel ply is positioned between the first glue flange and one or more of the first set of fixtures. Since the fixtures are included in the mold cavity, they are likely to receive resin during the step of providing the resin to the mold cavity. Adding a peel ply between the fixture and the first glue flange makes it easier to separate the fixture from the first glue flange after the resin is cured, and it can reduce the amount of resin left on the first glue flange and / or the fixture.

[0014] In some embodiments, the method further comprises the step of removing the vacuum bag and detaching the first set of fixing means from the first glue flange after the step of curing the resin. In some embodiments, if necessary, the method further comprises the step of removing residual resin from the first glue flange. Residues on the first glue flange may result in a weaker bond between the two blade shell parts.

[0015] The present invention is advantageously used on both the leading edge and the trailing edge of the blade shell portion. Therefore, in some embodiments, the method further comprises the following steps before the step of arranging a vacuum bag over the blade mould to form the mould cavity: - providing a second set of one or more fixtures at corresponding one or more fixture locations along a second edge of the mould, - arranging the second prefabricated glue flange in the blade mould using the second set of fixing means as position reference, whereby the second glue flange is arranged in a second position relative to the blade mould.

[0016] This provides the advantages of the invention described above on both the leading edge glue flange and the trailing edge glue flange, including accurate positioning of the glue flanges by including fixing means in the mould cavity and easier lay-up and manufacture of the blade shell section.

[0017] In some embodiments, after curing the resin and before assembling the first blade shell part and the second blade shell part, the method further comprises: - applying glue to the first side of the first glue flange and / or to the inner surface of the second blade shell part, and - assembling the first blade shell part and the second blade shell part, whereby the first blade shell part and the second blade shell part are bonded to each other at least via the first glue flange.

[0018] The above steps provide an optimal bond between the first blade shell part and the second blade shell part, since the first glue flange is already correctly positioned. If glue is provided on the inner surface of the second blade shell part, the glue is provided in a position facing the first side of the first glue flange in order to provide a bond between the first glue flange and the second blade shell part.

[0019] In some embodiments where the method is applied on both the leading edge and the trailing edge, after curing the resin and before assembling the first blade shell part and the second blade shell part, the method further comprises: - Glue is also applied to the first side of the second glue flange and / or to the inner surface of the second blade shell part.

[0020] If glue is provided on the inner surface of the second blade shell part, the glue is provided in a position facing the first side of the second glue flange in order to provide a bond between the second glue flange and the second blade shell part.

[0021] The above method is suitable for use with different wind turbine blade elements provided in a mould as part of the manufacture of a wind turbine blade shell. In some embodiments, the first blade shell portion is a suction side or a pressure side of a wind turbine blade shell portion. In some embodiments, the first edge of the mould corresponds to a trailing edge of the first blade shell portion. The trailing edge is typically more complex and more difficult to handle and assemble than the leading edge, and therefore the method is particularly advantageous when used for the trailing edge.

[0022] A second aspect of the invention provides a system for manufacturing a wind turbine blade shell comprising a first wind turbine blade shell portion and a second wind turbine blade shell portion. The system comprises: - a blade mould for forming a first blade shell part, a set of one or more fixing devices attached at corresponding one or more positions along the first edge of the blade mould, the set of fixing devices being configured to cooperate with the prefabricated gluing flange to ensure that during manufacturing of the first blade shell part in the blade mould, movement of the prefabricated gluing flange is limited by the set of fixing devices so as to prevent movement of the gluing flange beyond a desired final position of the gluing flange.

[0023] In some embodiments, the system further comprises a vacuum bag arranged over the blade mold to form a mold cavity, wherein the mold cavity comprises a set of fixtures.

[0024] In some embodiments, the set of fixing means is reconfigurable to allow the set of fixing means to be adapted to cooperate with prefabricated glue flanges of different shapes. This makes the system more flexible.

[0025] In some embodiments, the system comprises a second set of one or more fixing means attached at corresponding positions along a second edge of the blade mould and arranged similarly to the set of fixing means on the first edge. This allows the system to be used to provide accurate positioning of the glue flange at both the leading edge and the trailing edge of the first blade shell part.

[0026] A third aspect of the invention provides a composite wind turbine blade shell.The composite wind turbine blade shell according to the third aspect is obtained using the method according to the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be explained in detail below with reference to the embodiments shown in the drawings.

[0028] Figure 1 A wind turbine is shown.

[0029] Figure 2 A wind turbine blade is shown.

[0030] Figure 3a-3e A root end portion of a mould for manufacturing a first blade shell portion of a wind turbine blade shell is shown.

[0031] Figures 4a-4j A method according to the invention is shown, in particular for producing a wind turbine blade shell.

[0032] Figures 5a-5f It further shows Figures 4a-4j The method shown in . DETAILED DESCRIPTION

[0033] Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. The same reference numerals may refer to the same elements throughout. The accompanying drawings illustrate selected ways of implementing the present invention and should not be interpreted as limiting the scope of the claims. The features in the drawings are not necessarily drawn to scale.

[0034] Figure 1 A conventional modern upwind wind turbine 2 according to the so-called "Danish concept" is shown, having a tower 4, a nacelle 6 and a rotor with a substantially horizontal rotor axis. The rotor comprises a hub 8 and three blades 10 extending radially from the hub 8, each blade 10 having a blade root 16 closest to the hub and a blade tip 14 farthest from the hub 8.

[0035] Figure 2A schematic diagram of a wind turbine blade 10 is shown. The wind turbine blade 10 has the shape of a conventional wind turbine blade and includes a root region 30 closest to the hub, a profile or airfoil region 34 farthest from the hub, and a transition region 32 between the root region 30 and the airfoil region 34. The blade 10 includes 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. The outermost point of the blade 10 is the tip end 15, which is located opposite the root end 31 attached to the wind turbine hub 8.

[0036] The airfoil region 34 (also referred to as the profile region) of the wind turbine blade has an ideal or nearly ideal blade shape with respect to generating lift, while the root region 30 has a substantially circular or elliptical cross section for structural reasons, for example, which makes it easier and safer to mount the blade 10 to the hub. The diameter (or chord) of the root region 30 may be constant or may vary along the root region 30. The transition region 32 has a transition profile that gradually changes 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 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 chord generally decreases with increasing distance from the hub.

[0037] The shoulder 40 of the blade 10 is defined as the location where the blade 10 has its maximum chord length. The shoulder 40 is typically located at the boundary between the transition region 32 and the airfoil region 34. Figure 2 Also shown is the longitudinal extension L of the blade 10 B .L B The longitudinal axis of the blade 10 is also represented.

[0038] The blade is typically made of a pressure side shell portion 36 and a suction side shell portion 38 that are glued to each other along a join line at the leading edge 18 and the trailing edge 20 of the blade 10. As also described above, the join line is usually supplemented by an internal glue flange. The present invention addresses how to ensure that the glue joint provided by the internal glue flange provides as much structural strength as possible to the blade.

[0039] Figure 3a-3e A method according to the invention is shown for manufacturing a first wind turbine blade shell part. Figures 4a-4j and 5a-5f and the associated descriptions.

[0040] Figure 3a A portion of a blade mould 50 for manufacturing the suction side shell portion 38 of a wind turbine blade is shown. Figure 3a The blades are shown (see Figure 2) of the blade mold 50 near a portion of the root region 30, the transition region 32 and the airfoil region 34. The blade mold 50 has a first edge 51, a second edge 52 and a layup surface 53 for laying up fiber reinforcement materials for manufacturing a composite wind turbine blade, such as fiber mats, spar caps, main laminates, shear web portions, core material, etc. The edges 18', 20' of the mold surface 53 correspond to the leading edge 18 and the trailing edge 20, respectively, of the blade shell to be manufactured.

[0041] Figure 3b Two fixing devices 61 and 71 are shown attached to Figure 3a 51 of the mold shown in . In this example, each of the fixing means 61 and 71 includes a glue flange stopper portion 63, 73 and an attachment means 62, 72 for firmly attaching the glue flange stopper portion 63, 73 to the first edge 51 of the mold 50. In order to make the method robust, the glue flange stopper 63, 73 and the attachment means 62, 72 are made so that when air is extracted from the mold cavity defined by the mold 50 and the vacuum bag, they do not change shape when exposed to pressure from the vacuum bag. The stopper 63, 73 and the attachment means 62, 72 can be made, for example, of a composite material with sufficient thickness, or of a metal (such as stainless steel or aluminum or equivalent material) with sufficient thickness without buckling due to pressure. As mentioned above, the stopper should be shaped so as to follow the contours of those parts of the glue flange that are in contact with it.

[0042] Figure 3b The stops 63, 73 in FIG. 1 are shown as being plate-shaped, and two stops are shown. This is a matter of design. The stops may be narrower or wider, and each of the stops 63, 73 and its corresponding attachment means 62, 72 may be formed as a single piece, rather than as a single piece. Figure 3b The number of fixing means, the size of the fixing means and the shape of the fixing means are selected so that the shape of the glue flange does not change significantly during air extraction.

[0043] exist Figure 3c In a subsequent step shown in , fiber reinforcement material 74 is added to the mold according to the specific design of the first blade shell part. Figure 3c As indicated in , the fiber reinforcement material at the transition from the mold surface 53, and the opposing mold edges 51 , 52 define the trailing edge 20 and the leading edge 18 of the blade shell, respectively.

[0044] Resin is subsequently added to the fiber reinforcement material to form a fiber reinforced first blade shell part.

[0045] like Figure 3dAs shown in Figure 8, after arranging the fiber reinforcement material, a glue flange 81 is added to the layup. The glue flange has a lower portion (not visible in this view but indicated in dotted lines) which will become part of the first blade shell part during manufacture, and a portion which will later be joined to the second blade shell part when the blade shell parts are assembled to form a complete blade shell.

[0046] exist Figure 3d In the example shown in FIG. 8 , the glue flange 81 is held in a first position on the fiber reinforcement material 74 by the fixing means 61 , 71 . In this example, and as Figure 3d As shown in more detail in the lower part of the , adhesives 84 and 94 are wrapped around the upper edge 82 of the glue flange 81 to temporarily fix the glue flange to the fixing devices 61, 71 respectively. The adhesive may be, for example, a pressure sensitive adhesive, such as an adhesive tape. It may also be a fiber material, such as a fiber mat, which is glued to the glue flange stoppers 63, 73 and wrapped around the upper edge 82 of the glue flange 81 and glued to the glue flange 81. The glue flange may also be temporarily held by the fixing device using a wire. Alternatively or in addition, the fiber material (such as a fiber mat) may be used as an attachment strip by being glued to the glue flange 81 on the surface that meets the fiber material 74 in the mold, and the attachment strip is further directly or indirectly attached to the first edge 51 of the mold (such as, sewn to other fiber materials arranged on the first mold edge or directly fixed to the first mold edge 51). During resin infusion, such an attachment strip will become part of the first blade shell part, and the above-mentioned other devices need to be removed.

[0047] The shape of the fixing means, in particular the shape of the glue flange stops 63, 73 that meet the glue flange 81, should be shaped so that they follow the local contour of the glue flange 81. This provides the best end result because it helps to ensure that the glue flange is correctly positioned after the air is evacuated from the mold cavity and distributes the pressure on the glue flange 81 over a larger area. In addition, the number of stops and / or their position along the mold 50 should be such that the glue flange 81 is not allowed to flex when the air is evacuated from the mold cavity, because flexure of the glue flange during the manufacturing process causes the glue flange 81 to exert continuous forces on the surrounding components after the manufacture of the blade shell part. The shape and number of the fixing means are design issues and may depend on, for example, the characteristics of the glue flange 81 and the blade shell part. A more flexible glue flange requires more glue flange stops than a more rigid glue flange.

[0048] like Figure 3d As shown in FIG. 1 , the glue flange stops 63, 73 substantially follow the contour of the glue flange 81. As described below, the glue flange 81 moves to a slightly different final position, which is Figure 3dIn the final position, the glue flange stops 63, 73 follow the contour of the glue flange 81. This Figure 4e-4f and 5a-5b, which will be described later in this specification.

[0049] A peel ply (not shown) may be added between the glue flange stopper 63, 73 and the glue flange 81 to reduce or prevent adhesion between the glue flange stopper 63, 73 and the glue flange 81, which would occur because, according to the present invention, the glue flange stopper 63, 73 is actually co-injected with the glue flange 81. Arranging the peel ply in this manner makes it easier to separate the glue flange 81 from the glue flange stopper 63, 73 after curing of the resin.

[0050] After the above steps, a vacuum bag is added over the mould. This is shown and described later in this specification. The vacuum bag is arranged so as to form a mould cavity which comprises not only the fibre reinforcement 74 and the glue flange 81, but also the fixing means 61, 71, or at least part of the fixing means, such as the glue flange stoppers 63, 73 if they can be embedded in the mould cavity without embedding the attachment means 62, 72 (for example, using an adhesive material to seal the vacuum bag in a way that the attachment means 62, 72 are located outside the mould cavity and the glue flange stoppers 63, 73 are located inside the mould cavity)). This means that the fixing means 61, 71 or at least the glue flange stoppers 63, 73 are poured together with the glue flange. After the vacuum bag is added, the mould cavity is evacuated and resin is poured into the mould cavity and the resin is allowed to cure. As Figure 3e This transforms the fiber reinforced material 74 into a composite material 75, and the glue flange 81 is in the final position of the glue flange (as indicated in FIG. Figure 3e The steps of adding the vacuum bag, evacuating the air, infusing the resin and curing the resin are as follows. Figure 3a-3e are not shown, but they are related to Figures 4a-4j and Figures 5a-5f It is shown in relation.

[0051] The results of the above methods are Figure 3e As described above, the glue flange 81 is in the final position 81 'and is glued to the composite material 75. The final position 81 'may be different from the first position in which the glue flange 81 is initially attached to the fixture. This will be shown in more detail below.

[0052] Although the above method causes the glue flange to become glued to the fixture during the curing of the resin poured into the mold cavity, this method always results in easier and more accurate positioning of the glue flange 81 .

[0053] like Figure 3b-3dAs shown in FIG, the different fixing means 61, 71 are typically shaped specifically for a certain position on the first mould edge 51 and a certain portion of the glue flange 81 (not coincident along its axis).

[0054] The fixture is typically reusable for manufacturing a plurality of blade shell sections of the same type. Cleaning of the fixture may be necessary between manufacture of blade shell sections, but this is a minor problem compared to the advantages provided by the invention, particularly the high precision and relative ease of positioning of the glue flanges during manufacture.

[0055] By making the fixture reconfigurable, the fixture can be used for different blades and glue flanges. It must be ensured that the fixture does not move or change position during air extraction. A reconfigurable fixture is not shown herein.

[0056] Figures 4a-4j The process of manufacturing the first blade shell part is shown during Figure 3a-3e A portion of the cross section II indicated in FIG.

[0057] Figure 4a Corresponds to Figure 3a , and shows Figure 3a A portion of an empty blade mould 50 near the trailing edge 20 ′ at the cross section II indicated in FIG. Figure 4a A first edge 51 of the mould is shown and also a portion of the mould surface 53 is shown.

[0058] Figure 4b As shown in the corresponding Figure 3b As will be described in further detail below, the glue flange stopper 63 faces the mold 50 to engage with the glue flange 81 and limit the movement of the glue flange 81. In this example, and also as described with respect to Figure 3b As described, the attachment means 62 securely attaches the glue flange stop 63 to the mould edge 51, ensuring that the glue flange stop 63 remains securely in the same position during air extraction, which is known to be a process that applies considerable pressure.

[0059] Figure 4c Corresponds to Figure 3c , and the addition of a fiber reinforcement material 74 is shown on the mold surface 53. For illustration purposes, the fiber reinforcement material in the relevant area is shown as a plurality of fiber mats 74, but it may additionally or alternatively be one or more other material types.

[0060] Figure 4d Corresponds to Figure 3d , and a glue flange 81 is shown added to the layup. Figure 4d As mentioned above, Figure 3dAs described in detail, the glue flange 81 is temporarily retained on the glue flange stopper 63 by the adhesive material 84 . Figure 4d The glue flange 81 is shown in a first position in which it is in contact with the fiber mat 74. Thus, in this example, the fiber mat 74 partially defines the first position of the glue flange 81. Since the glue flange 81 is not securely attached at this point, the glue flange 81 is movable, and thus the fiber mat 74 partially defines the first position of the glue flange 81, i.e., the position of the glue flange 81 before the step of extracting air from the mold cavity. As will be shown below, the glue flange typically shifts during air extraction.

[0061] Figure 4e The vacuum bag 90 is shown to have been loosely arranged on top of the mold to form the mold cavity. Figure 4e It can be seen that, as also described above, not only the fiber mat 74 and the glue flange 81, but also the fixture 61 (including the attachment means 62 and the glue flange stop 63) is contained within the mold cavity, which means that the fixture 61 will receive resin during infusion. The shape of the fixture (including the attachment means 62) should be suitable to minimize the amount of resin that ends up embedded in the fixture after infusion. Therefore, the width of the attachment means 62 should be as small as possible, and it may be advantageous to ensure that the attachment means 62 is as close to the first edge 51 as possible, thereby reducing the space created by the attachment means 62. The glue flange stop should also be as narrow as possible, but this is limited by the glue flange 81 not being able to flex when the air is evacuated.

[0062] Figure 4f The blade shell portion is shown after the air has been evacuated and resin has been infused into the mould cavity. The vacuum bag 90 is now snug and pressed against the fibre layer 74 and the glue flange 81 (and any other components in the mould cavity). Figure 4f and Figure 4e By comparison, it can be seen that the fiber layer 74 (now the composite 75) has a thickness that is less than the thickness before the air is evacuated (see Figure 4e ). The extraction of air causes the fiber mat to compress due to the pressure from the vacuum bag, which reduces the thickness of the fiber layer 74. Figure 4e and 4f It can also be seen that the glue flange 81 is in a final position 81' which is different from the first position before the air is evacuated from the mould cavity. The compression of the fibre mat 74 and the pressure from the vacuum bag forces the glue flange closer to the mould surface.

[0063] Crucially, from Figure 4e and 4f As can be seen in FIG. 1 , the glue flange stop 63 allows movement of the glue flange during air extraction, but also limits movement beyond the final (and desired) position, preventing further movement of the glue flange. Figure 4e The space between the lower part of the glue flange stopper 63 and the glue flange 81 is shown, and the space has been closed during the air extraction, as shown in FIG. Figure 4f The limitation of the movement of the glue flange 81 by the glue flange stop 63 helps to ensure that the glue flange 81 is accurately positioned in the desired final position 81 ' (if different from the first position).

[0064] Figure 4g The final product is shown after removal of the vacuum bag 90, the adhesive 84 and the fixing means 61 including the attachment means 62 and the glue flange stop 63. As described above, by virtue of the invention, the glue flange 81 ' is in the desired position.

[0065] Figure 4h The addition of glue 95 on a first surface of the glue flange 81 ' is shown (the glue flange 81 is in the final position). The first surface will face the second blade shell part which together with the first blade shell part forms a wind turbine blade shell. Before adding the glue 95, the first surface of the glue flange 81 ' may need to be prepared because this surface has been in contact with the glue flange stop 63 and there may be resin residue on it after the fixing device 61 is removed. Such residue may result in a poor bond between the glue flange 81 ' and the glue 95, which is unacceptable.

[0066] Figure 4i A second blade mould 50' is shown holding a second blade shell part. The second blade mould 50' is arranged above the first blade mould 50. The first edge 51 of the first mould 50 meets the first edge 51' of the second mould 50'. This is a general step of assembling the blade shell parts to form a complete blade shell. The second blade shell part in this example comprises a composite material 75' similar to the composite material 75 in the first blade shell part.

[0067] When the moulds 50 and 50' are brought close to each other, the glue flange 81' is glued to the composite 75' in the second blade shell part by means of the glue 95, thereby creating a secure bond between the two shell parts. According to an advantage of the invention, the glue flange 81' is positioned as intended and will therefore engage the second blade shell part in the same precise manner, resulting in a secure bond.

[0068] Figure 4j The resulting assembled blade shell section is shown (again only near the trailing edge 20 of the wind turbine blade shell, which is the relevant part). Additional elements may be used to glue the blade shell sections together, such as a glue bond that joins the composites 75 and 75' together where they meet at the trailing edge 20.

[0069] Figures 5a-5fThe use of another fixing device 71 further up the blade mould 50 in the direction of the tip of the blade to be manufactured is shown, as also in FIG. Figure 3b-3d As is typical, a single glued flange is used in this example, so Figures 5a-5f The glued flange 81 shown in FIG. Figure 3d-3e The same as the glue flange shown in 4d-4h. Therefore, the same reference numerals 81 and 81' are used below. Figures 5a-5f The view in corresponds to Figure 3a-3e The cross section KK indicated in .

[0070] Figure 5a Shows the corresponding Figure 4e step, wherein the vacuum bag has been loosely arranged on the mold 50, but the mold cavity has not yet been evacuated. Figure 4e Similarly, the glue flange 81 is held on a glue flange stop, in this case Figure 3b-3d The glued flange stopper 73 (comprising the Figure 3d Detail of the far lower left corner). The glue flange stop 73 is attached to the first mould edge 51 by means of the attachment means 72. As described above and as Figure 3b-3d As shown in FIG. , the fixing device 71 has Figures 4a-4f The fixing device 61 has different shapes. Figure 4e Similarly, before air is evacuated from the mold cavity, there is a gap between portions of the glue flange 81 and the glue flange stop 73 .

[0071] As about Figure 3d and 4d As discussed, when the glue flange 81 is added to the layup and before the air is evacuated, the glue flange 81 initially remains in the first position. Figure 4d The first position at the cross section II is shown in FIG. Similarly, Figure 5a The gluing flange 81 is shown in a first position at the cross section KK. Figure 3a-3e and Figure 4i-4j As can be seen in FIG. 1 , the glue flange has a different cross-sectional shape at cross section KK due to the different shape of the airfoil of the blade at cross section KK from the shape of the airfoil at cross section II (the latter being close to the root and therefore having a shape very close to a circle). Figure 4e Similarly, the glue flange 81 is attached to the glue flange stop 73 by an adhesive 94, such as a pressure sensitive adhesive, adhesive tape, or a fabric material that is glued to the glue flange stop 73 and the glue flange 81. Figure 3d and 4cAs shown in FIG. 1 , at cross section KK the glue flange rests on a fiber mat 74 which, for simplicity, is shown to be the same fiber mat as that laid down at cross section II.

[0072] and Figure 4f similar, Figure 5b The blade shell section is shown after the air has been evacuated and the resin has been poured into the mould cavity. Again, the vacuum bag is snug and pressed against the fibre layer 74 and the glue flange. The fibre layer 74 has been compressed and the resin has been poured into the mould cavity, which has turned the fibre layer into a composite 75. Figure 5b Also shown is the movement of the glue flange 81 from the first position to the second position 81 ′ due to the pressure from the vacuum bag and the compression of the fiber layer 74 . Figure 5a The first position 81 shown in Figure 5b It is shown as a dotted line. Figure 4f Similar to the glue flange stop 63 in the cross section, the glue flange stop 73 at the cross section KK allows the glue flange 81 to move from the first position to the final position 81 ', closing the gap about Figure 5a 81 '. As a result, the gluing flange 81 'is also correctly positioned at the cross section KK, i.e. as desired. As described above, the fixing means are arranged along the mould in such a way that no significant deflection of the gluing flange 81 is allowed when air is evacuated from the mould cavity. The above fixing means are merely exemplary. Narrower or wider gluing flange stops may be used, and the number of gluing flange stops is selected to ensure that the gluing flange 81 does not deflect.

[0073] Figure 5c The blade shell part is shown in the mould after the infused resin has cured and the vacuum bag 90 and the fixture 71 have been removed. In preparation for gluing the glue flange 81 ' to a second blade shell part, it may be necessary to clean the surface of the glue flange 81 ' where it contacts the glue flange stop 73, or where resin got to other places of the glue flange 81 ' during the infusion of the resin.

[0074] Figure 5d Glue 95 is shown provided along the glue flange 81 ' in preparation for assembling the blade shell portion with the second blade shell portion. Figure 4h As mentioned, glue 95 is applied to a first surface of the glue flange which will face the second blade shell part when the blade shell parts are assembled.

[0075] Figure 5e Corresponds to Figure 4i, and shows a point in time in which a second mould 50' with a second blade shell part is arranged above the first blade mould 50 and the second blade shell part is in contact with the glue 95, whereby the shell parts are bonded to each other via the glue flange 81', whereby the glue flange 81' provides additional strength to the blade shell. In this example, as is typically the case, the blade mould 50' is identical to the blade mould at cross section II, and as mentioned above, the glue flange is also typically identical to the glue flange at cross section II, since only a single glue flange is typically used in a blade shell. However, the invention is not limited to use with a single glue flange, but is readily applicable if several glue flange components are used in the blade shell.

[0076] Figure 5f The trailing edge portion of the resulting blade shell at cross section KK is shown, with the glued flange 81 ' providing structural strength to the blade shell.

[0077] The above description focuses mainly on the trailing edge. However, a leading edge glue flange for the leading edge 18 of the blade shell may also be provided, and it may be provided as part of the above method for the trailing edge glue flange 81. Thus, the fixing means is arranged on the second edge 52 of the mould (e.g. Figure 3d The second edge 52 is shown in FIG. 1 ). The shape and number of the fixing means are adapted to the shape of the leading edge glue flange so as to support the leading edge glue flange during the extraction of air to prevent deflection. The above description of the trailing edge glue flange is also applicable to the attachment of the leading edge glue flange.

[0078] Reference Mark List 2. Wind Turbines 4 Tower 6. Cabin 8 Hub 10 blades 11, 12 Blade shell part 14 Leaf tip 15 distal end 16 Blade root 18 Leading edge of blade shell 18' Blade Mould Leading Edge 20 Trailing edge of blade shell 20' Blade Mold Trailing Edge 30 Root Zone 31 Root end 32 Transition Zone 34 Airfoil area 36 Pressure side shell 38 Suction side shell 40 Blade shoulder 50 Blade mould for a first wind turbine blade shell section 50' Blade mould for second wind turbine blade shell section 51 First edge of blade mould 52 Second edge of blade mold 53 Blade mold laying surface 61, 71 Fixtures 62, 72 Attachment device for gluing flange stop 63, 73 Glued flange stop 74 Fiber-reinforced materials, fiber mats 75 Composite Materials 81 Gluing flange / first position of glueing flange 81' Final position of glued flange 82 Glue flange upper edge 84, 94 Adhesive for retaining glued flanges

Claims

1. A method of manufacturing a wind turbine blade shell comprising a first wind turbine blade shell portion (36) and a second wind turbine blade shell portion (38), the method comprising: - providing a blade mould (50) for forming said first blade shell part, - arranging a fiber reinforcement material (74) in the blade mould, - providing a first set of one or more fixing means (61, 71) at corresponding one or more fixing means positions along a first edge (51) of the blade mould, - arranging a first prefabricated glue flange (81) in the blade mould using the first set of fixing means as a position reference, whereby the first glue flange is arranged in a first position relative to the blade mould, - placing a vacuum bag over said blade mould so as to form a mould cavity, wherein said fibre reinforcement material, said first glue flange and said first set of fixing means are contained within said mould cavity, - evacuating air from the mould cavity, - providing resin into the mold cavity, and - Curing the resin, thereby forming the first blade shell part.

2. A method according to claim 1, wherein the first glue flange is shaped so that when the first blade shell part and the second blade shell part are assembled with each other to form the blade shell, the glue applied to the first side of the first glue flange will engage with the inner surface of the second blade shell part and thereby provide a bond between the first blade shell part and the second blade shell part.

3. A method according to any of the preceding claims, wherein before the step of extracting air from the mold cavity, the first glue flange is maintained in a first position against the first group of fixing devices at least by attaching the first glue flange to one or more glue flange attachment devices (84) of the first group of fixing devices, such as by an adhesive, such as a pressure-sensitive adhesive.

4. Method according to any of the preceding claims, wherein said first set of fixing means (61, 71) comprises respective glue flange stops (63, 73) defining a position reference for said first glue flange.

5. A method according to any of the preceding claims, wherein the fiber reinforcement material and the first gluing flange are arranged such that, during the step of evacuating air from the mold cavity, the first gluing flange moves from the first position (81) to the final position (81') at least partially due to the force applied by the vacuum bag during the step of evacuating air from the mold cavity and / or at least partially due to the compression of the fiber reinforcement material in the mold cavity during the step of evacuating air from the mold cavity.

6. A method according to any one of the preceding claims, wherein a peel ply is positioned between the first glue flange and one or more of the first set of fixing means.

7. The method according to any one of the preceding claims, further comprising: After the step of curing the resin, the vacuum bag is removed and the first set of fixing means is detached from the first glue flange.

8. The method according to any one of the preceding claims, further comprising: Prior to the step of positioning the vacuum bag over the blade mould to form the mould cavity: - providing a second set of one or more fixtures at corresponding one or more fixture positions along a second edge (52) of the mould, - arranging a second prefabricated glue flange in said blade mould using said second set of fixing means as position reference, whereby said second glue flange is arranged in a second position relative to said blade mould.

9. The method according to any one of the preceding claims, further comprising: After curing the resin and before assembling the first blade shell part and the second blade shell part: - applying glue to the first side of said first glue flange and / or to the inner surface of said second blade shell part, and - Assembling the first blade shell part and the second blade shell part, whereby the first blade shell part and the second blade shell part are bonded to each other at least via the first glue flange, thereby forming the blade shell.

10. The method of claim 9 when dependent on claim 8, further comprising after curing the resin and before assembling the first blade shell part and the second blade shell part: - Applying glue to the first side of the second glue flange and / or to the inner surface of the second blade shell part.

11. Method according to any of the preceding claims, wherein the first edge (51) corresponds to a trailing edge (20) of a suction side (38) or a pressure side (36) of a wind turbine blade shell part.

12. A system for manufacturing a wind turbine blade shell comprising a first wind turbine blade shell portion (36) and a second wind turbine blade shell portion (38), the system comprising: - a blade mould (50) for forming said first blade shell part, - a set of one or more fixing devices (61, 71) attached at corresponding one or more positions along the first edge (51) of the blade mould, the set of fixing devices being configured to cooperate with the prefabricated gluing flange (81) to ensure that the movement of the prefabricated gluing flange is limited by the set of fixing devices during the manufacture of the first blade shell part in the blade mould.

13. The system of claim 12, further comprising a vacuum bag arranged above the blade mould to form the mould cavity, wherein the set of fixtures is arranged within the vacuum bag.

14. A system according to claim 12 or claim 13, wherein the set of fixing means is reconfigurable, thereby allowing the set of fixing means to be adapted to cooperate with pre-fabricated glue flanges of different shapes.

15. A composite wind turbine blade shell obtained using the method according to any one of claims 1 to 11.

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