Improvements related to a wind turbine blade root cover

Abstract

There is provided a blade root cover segment adapted to be assembled to a wind turbine blade to span a gap between the blade and a nacelle cover. The blade root cover segment includes a first end and a second end and comprises: a curved flange for abutting a corresponding curved surface of the wind turbine blade; a cover wall extending radially from the flange; and a tension band associated with the flange. The tension band includes a first end proximate to the first end of the blade root cover segment and a second end proximate to the second end of the blade root cover segment, and wherein the first end and the second end of the tension band include connecting means for connecting to a similar blade root cover segment and applying tension between similar blade root cover segments. The invention also encompasses a blade root cover including a plurality of blade root cover segments. The invention also extends to a method of assembling a blade root cover from a plurality of blade root cover segments.

Description

Field of the Invention

[0001] The present disclosure generally relates to a solution or device for covering the interface between the blade and the rotor hub of a wind turbine generator. Background Art

[0002] In a typical "horizontal axis" wind turbine, a nacelle mounted on a tower supports a rotor including a rotor hub and a plurality of blades. Each blade is connected at its root end to the rotor hub via a pitch bearing. The pitch bearing allows the blade to rotate or "pitch" about the axis of the blade. The rotor hub may be wholly or partially received by a spinner which protects the hub from the environment and improves the aerodynamics of the rotor.

[0003] Typically, the spinner includes blade openings overlying respective pitch bearings of the rotor hub, and each blade extends through the blade opening. Typically, the blade opening in the spinner is larger than the diameter of the pitch bearing to allow the blade to move laterally during installation. As a result, once the blade is installed on the pitch bearing, an uncovered annular gap exists between the spinner and the blade. Through this gap, the rotor hub is exposed to the environment and is particularly vulnerable to water tracking along the blade towards and into the rotor hub from the root.

[0004] Known methods for sealing the annular gap include a cover profile having at least one angled tapered section to deflect water away from the gap. Methods including more than one interacting cover profile are also known. The known cover profiles may be continuous around the circumference of the gap or divided into arcuate sections or segments and joined together. Current methods typically require the use of a sealing substance (such as Sikaflex TM ) to seal any gaps created by surface irregularities at the interface between the blade or spinner and the cover profile. Liquid sealants can be difficult and time-consuming to apply on-site and require dry, clean application conditions to function reliably.

[0005] It is in this context that the present invention has been devised. Summary of the Invention

[0006] According to a first aspect of the present invention, there is provided a blade root cover segment adapted to be fitted to a wind turbine blade to span a gap between the blade and a spinner cover. The blade root cover segment has a first end and a second end. The blade root cover segment comprises: a curved flange for abutting a corresponding curved surface of the wind turbine blade; a cover wall extending radially from the flange; and a tension band associated with the flange. The tension band includes a first end proximate to the first end of the blade root cover segment and a second end proximate to the second end of the blade root cover segment, and wherein the first and second ends of the tension band include connecting means for connecting to a similar blade root cover segment and for applying tension between similar blade root cover segments.

[0007] The invention also extends to a blade root cover comprising a plurality of blade root cover segments connected end to end in a loop.

[0008] The blade root cover segments can be attached to similar segments and can thus together form a string of cover segments linked together in a stepwise manner to form a complete blade root cover. The tension band is a separate component and is preferably made of a material having a higher tensile strength than the body of the blade root cover. Thus, the force required to hold the blade root cover on the blade can be provided by the tension established in the tension band, whereby the blade root cover segments can be made relatively light in weight as they do not need to be strong. One option is for the tension band to be a steel band and the cover segments to be made of plastic. Further benefits can be realized by considering how a wind turbine operates in extreme environmental conditions and the operating temperature requirements are in the range of -50°C to 70°C. In this temperature range, the thermal expansion of the plastic part is more significant than that of the metal part, so the thermal dimensional stability of the reinforcing band is advantageous as it ensures that the blade root cover remains firmly attached to the blade within the required temperature range. Similarly, the metal reinforcing band does not become brittle during low temperatures. The tension band can be a single component for each blade root cover segment, or it can comprise multiple parts for each blade root cover segment. In one embodiment, the tension band is two parts, one on each side and converging at the center. In an alternative embodiment, the tension band is one part from each side converging at the center to a central part.

[0009] Another advantage of the present invention is that since each blade root cover segment has a corresponding tension band, a damaged segment can be removed from the blade root cover without removing the entire assembled component. Thus, maintenance can be performed while the blade root cover is on the blade.

[0010] To help keep adjacent cover segments together, the first and second ends of the cover segments may include complementary mating features. Preferably, the mating features are defined on respective ends of the cover wall. The mating features permit adjacent cover segments to be assembled together and remain in place when assembling the blade root cover. In one embodiment, the complementary mating features include a locking mechanism. This helps lock adjacent cover segments together before connecting adjacent tension bands.

[0011] Although the complementary mating features can take various forms, in one embodiment, the complementary mating features include a convex feature on the first end of the cover wall and a concave feature on the second end of the cover wall.

[0012] As a further enhancement, the flange may include a sealing device for sealing against the surface of the blade. The sealing device may include at least one gasket component. Thus, when the blade root cover component is fixed to the blade surface, the gasket component seals against the underlying blade surface. As a result, there is no need to apply a liquid sealant.

[0013] To ensure that the tension band remains associated with, linked to, or otherwise attached to the blade root cover segment during handling and assembly, in one embodiment, the tension band is held on the blade root cover segment. Holding may involve holding the tension band in a groove defined in the flange.

[0014] The blade root cover segment may also include one or more reinforcing webs extending between the flange and the cover wall. Since the flange and the cover wall are relatively flat and thin components that extend at an angle to each other, the reinforcing webs provide a structure that increases the rigidity of the cover segment without significantly increasing the mass. The reinforcing webs may be configured to hold the tension band on the blade root cover segment.

[0015] The connecting device of the tension band may include a bracket that is connected to the flange. Thus, the brackets of the respective tension bands of adjacent blade root cover segments can be fastened together to connect the adjacent cover segments. An adjustable connector may be provided that is configured to connect to adjacent tension bands, such as between adjacent brackets, and adjust the spacing between the adjacent tension bands.

[0016] In another aspect, the present invention provides a method of installing a blade root cover on a wind turbine blade, wherein the blade root cover includes a plurality of separate and interconnected blade root cover segments. The method includes the steps of:

[0017] Supporting a first blade root cover segment on the blade;

[0018] A blade root cover assembly is formed by providing a second blade root cover segment to a position adjacent to the first blade root cover segment of the blade and connecting the second blade root cover segment to the first blade root cover segment using the connecting means of the respective blade root cover segments; and

[0019] A further blade root cover segment is connected to the blade root cover assembly of the first and second blade root cover segments to increase the circumferential length of the blade root cover assembly until a complete blade root cover is formed.

[0020] The step of supporting the first blade root cover segment on the blade may include: suspending the first blade root cover component from a support member that is separate from the blade.

[0021] The step of suspending the first blade root cover segment includes: extending a tether line from the first blade root cover segment above the upper part of the blade root to the support member. It should be noted that using a tether line is an option, but the blade root cover can also be installed without using a tether line.

[0022] The method may further include the step of moving the first blade root cover segment in a stepwise manner while connecting a further blade root cover segment to the blade root cover assembly.

[0023] The method may include the steps of pre-assembling the blade root cover on the blade and then applying circumferential tension to the blade root cover through the connecting means.

[0024] It should be appreciated that the preferred and / or optional features of the first aspect of the present invention may be combined with other aspects of the present invention. The various aspects of the present invention are defined in the appended independent claims, and the advantageous features are defined in the appended dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Below, with reference to the drawings, the above and other aspects of the present invention will be described by way of example only, in which:

[0026] Figure 1 is a front view of a horizontal axis wind turbine into which an embodiment of the present invention may be incorporated;

[0027] Figure 2 is an illustration Figure 1 of a component of the rotor hub of the wind turbine shown, the component including a hub body, a nacelle, and blades;

[0028] Figure 3 is a partial perspective view of the nacelle and blades as shown in accordance with an embodiment of the present invention, but further equipped with a blade root cover; Figure 2 shown;

[0029] Figure 4Yes Figure 3 is a perspective view of the blade root cover, but shown in isolation;

[0030] Figure 5 Yes Figure 3 is an exemplary cross-sectional view of a portion of, showing the relative positioning of the blade root cover, the blade, and the fairing;

[0031] Figure 6 is a perspective view of a portion of the blade root cover, focusing on the interface or junction between adjacent blade root cover sections;

[0032] Figure 7 is a perspective view of a single blade root cover section;

[0033] Figure 8 Yes Figure 7 is a view of the bottom of one end of the blade root cover section shown in;

[0034] Figures 9a to 9f is a series of exemplary views showing the process of mounting the blade root cover to the blade;

[0035] Figure 10 is a perspective view of an alternative embodiment of the blade root cover;

[0036] Figure 11a and Figure 11b show Figure 10 the central portion of;

[0037] Figure 12 is a perspective view of the tension band portion; and

[0038] Figure 13 show Figure 10 the end of.

[0039] Note that the same or similar features are denoted by the same reference numerals in the different figures. DETAILED DESCRIPTION

[0040] Referring to Figure 1 and Figure 2 , the wind turbine 2 includes a nacelle 4 that is supported on a generally vertical tower 6, which in turn is mounted to a foundation 8. The foundation 8 can be on land or all or part underwater. The nacelle 4 supports a rotatable rotor 10 that includes a rotor hub 12 at the front of the nacelle 4. The rotor hub has a set of blades 14 attached thereto, which drive the rotor hub 12 to rotate in a common manner under the influence of the wind flow.

[0041] As is known, the rotor hub includes a hub body 16 to which a nacelle cover or more simply a "nacelle" 18 is attached. The hub body 16 is the main structural member of the rotor hub 12 and is the assembly to which the blades 14 are attached and which is coupled to the main rotor shaft 20 of the wind turbine 2. In view of Figure 1 a broad view of the wind turbine 2 is shown, Figure 2 and the rotor hub 12 is schematically depicted, in which the positional relationship between the hub body 16, the nacelle 18, and the rotor blades 14 is more comprehensively considered. The nacelle 18 is an aerodynamic fairing, typically of composite plastic construction, which protects the internal hydraulic and electrical systems (not shown) housed within the hub body 16 from the external environment. As can be seen, the hub body 16 includes blade connectors 22 for the respective rotor blades 14, Figure 2 and only one blade is shown. Each blade connector 22 includes a blade bearing (not shown) having a circular flange to which the root 24 of the blade is attached. A pitch system (not shown) is housed within the hub body 16 and functions to rotate the pitch bearing and thus also the blade 14 about the longitudinal axis of the blade. This arrangement is typical in wind turbine designs and is not described in further detail here for the sake of brevity.

[0042] Figure 3 a view of the nacelle 18 and one of the blades 14 is shown. As can be seen, in this view, the blade 14 extends laterally from the nacelle 18 through a blade aperture 26.

[0043] To allow sufficient clearance for the blade 14 to pitch about its longitudinal axis, the blade aperture 26 of the nacelle 18 defines a circumferential gap 28 around the blade root 24 (see Figure 5 ). However, during wet weather, this gap 28 serves as a path through which water can enter the interior of the nacelle 18 and thus into the hub 12. Therefore, it is generally important to protect the hub from water ingress, and salt water can be particularly damaging. To this end, a blade root cover 30 is provided. In Figure 3 it can be seen that the blade root cover 30 is installed in place on the blade 14 so as to cover the annular gap, while Figure 4 shows that the blade root cover 30 is an assembly of individual blade root cover segments 32 or sections, and for the sake of brevity, only three of these blade root cover segments are labeled. In the illustrated embodiment, the blade root cover 30 comprises a total of twelve cover segments 32. However, it should be understood that this is merely an example and should not be considered limiting. More details of each individual blade root cover segment 32 will be described in the discussion below.

[0044] Figure 3 andFigure 4 shows the blade root cover 30 at a relatively high level of detail, but Figure 5 shows different perspective views of a cross-section through the root 24 of the blade 14, the fairing 18, and the blade root cover 30. Figure 5 clearly illustrates the annular gap 28 defined between the circumferential lip 34 of the fairing 18 and the blade 14, and how the blade root cover 30 is configured to prevent water ingress by covering the gap 28.

[0045] As can be seen in Figure 5 the cross-section of the blade root cover 30 is generally L-shaped, as defined by a relatively narrow base or flange 40 and an upright wall 42. The wall 42 meets the flange at an elbow 44 such that the wall 42 is inclined relative to the flange 40. In this embodiment, by way of example only, the wall 42 defines a large angle of inclination within the range of 60 degrees. In other words, the cover wall 42 extends radially from the flange 40. In this sense, the term "radially" does not refer to a strict 90-degree angle between the flange and the cover wall, but rather the cover wall is inclined such that when mounted on the blade, the cover wall extends away from the flange such that the height of the wall increases in the radial dimension away from the blade.

[0046] The flange 40 has dimensions defined by a first edge 40a and a second edge 40b in the width direction. The first edge 40a is a free edge, while the second edge 40b is connected to the inclined wall 42. Similarly, the flange 40 has dimensions defined by a first end 40c and a second end 40d in the length direction. The flange 40 abuts an adjacent surface of the blade 14 and thus serves as an interface with the blade 14. The width of the flange 40 is configured such that the free edge 40a of the flange 40 is radially aligned with the circumferential lip 34 of the fairing 18 that defines the blade aperture 26. Note that the position of the blade root cover 30 is such that a small net clearance 41 is established between the wall 42 and the fairing 18. The clearance 41 can be useful for reducing wear on the blade root cover 30. Alternatively, the blade root cover 30 can be configured and assembled to the blade such that the wall 42 contacts the fairing 18, which can improve weather resistance.

[0047] Now, will also be described Figure 6 、 Figure 7 and Figure 8 which show various perspective views of an example of one of the blade root cover segments 32 that form the complete assembly of the blade root cover 30.

[0048] As already mentioned, in the illustrated embodiment, the blade root cover 30 includes twelve blade root cover segments 32, so that when considering a circular cross-section through the blade root 24, each of the segments 32 spans an arc of approximately 30 degrees. Due to the large diameter of the blade root 24 and the relatively small circumferential span of the blade root cover segments 32, the flanges 40 of the segments 32 have a shallow curvature, as can be seen from the figures.

[0049] As can be seen, the blade root cover segment 32 has an elongated shape and has a first end 44 and a second end 46 that define opposite ends of the flange 40 and the wall 42. Advantageously, each of the blade root cover segments 32 is configured to connect to an adjacent and substantially identical blade root cover segment 32 so as to form a complete blade root cover 30, as Figure 4 shown. In other words, the blade root cover segments are connectable to each other. In addition to being connectable to similar segments, each blade root cover segment 32 is provided with a tensioning device 48 that is operable, when a set of blade root cover segments 32 are assembled together, to form a complete annular blade root cover 30 and to apply a tension between each of the blade root cover segments 30 so as to pull them tightly against the blade root 24 on which they are mounted.

[0050] As Figure 6 and Figure 8As shown, the tensioning device 48 is a tensioning band 50 associated with the flange 40. The tensioning band 50 takes the form of a strip of high tensile material such as steel, which is held on the flange 40 so that the tensioning band forms part of the blade root cover segment 32, since the tensioning band cannot be easily removed during handling or assembly. Importantly, the increased tensile strength of the tensioning band 50 provides the blade root cover 30 with the ability to withstand the hoop stress generated by such tension, i.e., the tension required for the assembled blade root cover 30 to apply a radially inwardly directed compressive force to the blade root 24 in order to hold the blade root cover 30 in a substantially fixed axial position on the blade. Since the compressive force is generated by the tensioning band 50, the remainder of the blade root cover segment 32 can be made of a relatively lightweight material such as plastic. The exact material is not critical to the present invention, but it is contemplated that the material will be cost-effective for sourcing and manufacturing. As a non-limiting example, options can include polyamides, polyethylenes, and other thermoplastic polymers, which can be suitable for producing segments in an injection molding process. Forming the blade root cover segments by injection molding is a very time-saving and material-saving way of manufacturing the article. Since all the segments are identical for all intents and purposes, the segments themselves are suitable for mass production in this way. The strength of the plastic parts of the blade root cover segments is not critical, as they only need to have primary structural integrity when installed on the blade; they do not serve as load-bearing components in the same way. The shrinkage load that secures the assembled blade root cover to the blade is generated by the tensioning band, which is preferably made of a material with a high tensile strength as described above.

[0051] It is also contemplated that the body of the blade root cover segment will be suitable for an additive manufacturing process.

[0052] In the illustrated embodiment, the tensioning band 50 is held on the upper surface of the flange 40. This can be achieved in various ways. As shown, the tensioning band 50 is located within a longitudinal groove 52 defined on the upper surface of the flange 40. In this embodiment, the groove 52 extends along the length of the flange 40. Clips or other suitable retaining members can be used to ensure that the tensioning band 50 remains located within the groove 52. In the illustrated embodiment, a plurality of upright fins or webs 54 span between the wall 42 and the flange 40. The webs 54 serve two purposes. First, they provide additional rigidity to the wall 42 relative to the flange 40, as they reduce the stress acting through the elbow 44. Second, the lower ends of the webs 54 extend above the groove 52 and prevent the tensioning band 50 from rising out of the groove 52. Suitable holes (not shown) can be provided in the webs to allow a person to more easily grasp the cover segment during installation. During installation, the holes can also be temporarily used to tie a rope to the cover segment.

[0053] At each end of the tensioning belt 50, there is provided a connecting device 56 in the form of a bracket 58 located at the first and second ends of the tensioning belt 50. In this embodiment, the bracket 58 is shown in the form of an L-shape and thus includes a base 58a adjacent to the tensioning belt 50 and a connecting flange portion 58b extending vertically upward from the base 58a. This is best seen in Figure 8 . The base 58a also includes retaining lugs 60 on its lower side (see Figure 7 ), which extend through corresponding holes (not shown) defined in the tensioning belt 50 and the flange 40. As can be seen, the retaining lug 60 has a head 62 which has an oval or stadium shape and thus forms a twist-locking feature for the bracket 56. Thus, in this way, the bracket can be used to lock the tensioning belt 50 to the flange 40 by using a quarter-turn fixing method. Thus, the bracket 56 is releasably held on the flange 40 and is also used to hold the tensioning belt 50 against the flange 40.

[0054] As already mentioned above, each of the blade root cover segments 32 in the blade root cover is connected to substantially the same segment so as to form a complete blade root cover, as shown in Figure 3 and Figure 4 . Figure 8 More details of the connection are shown, which shows the first blade root cover segment 32a engaging and connected to the second blade root cover segment 32b.

[0055] At the center of Figure 8 , the respective tensioning belts 50 of the first blade root cover segment 32a and the second blade root cover member 32b are joined together at their respective brackets 58. The tensioning device 48 includes means for joining and applying tension between the respective tensioning belts 50. This function is provided in part by the bracket 58 but also by an adjustable tensioning mechanism or "regulator" 70 which joins the respective brackets 58 together. In the illustrated embodiment, the regulator 70 is shown as a threaded bolt 72 having a nut 74, which nut is visible on the right side of the two brackets 58. Rotation of the nut 74 reduces the spacing between the brackets 58 and thus pulls the two blade root cover segments 32 more firmly together.

[0056] At this point, it should be realized that the regulator 70 can be provided by different means. For example, a different threaded mechanism such as a turnbuckle device can be used. Also, it is conceivable that a suitable ratchet device can be used to perform the same function of applying tension between adjacent tensioning belts 50.

[0057] One advantage of the blade root cover 30 is from Figure 5This is particularly obvious here. It can be seen that, due to the fact that the leeward or "sheltered" part of the blade root cover 30 adjacent to the annular gap 28, the regulator 70 can be accessed from the direction of the fairing 18. Therefore, access to the blade root cover segment 32 can be obtained through the interior of the fairing 18, enabling maintenance personnel to adjust the blade root cover 30 or even replace the blade root cover segment 32 in place without removing the blade root cover 30 from the blade.

[0058] By observation Figure 8 It can be envisioned that the adjacent blade root cover segments 32a, 32b are configured to cooperate with each other to improve the connection between them and also contribute to the process of joining the individual cover segments 32 together.

[0059] More specifically, the first end 76 of the wall 42 of the blade root cover segment 32a has a concave mating feature 78, while the second end 80 of the wall 42 has a convex mating feature 82. In this embodiment, the concave mating feature 78 is a groove or recess 79 defined between parallel wall portions 81 along the first end 76 of the wall 42, and the convex mating feature 82 is a rib or blade defined along the second end 80 of the wall, in fact, an extension of the wall 42, and it is configured and dimensioned to be received in the concave mating feature 78.

[0060] Therefore, when the adjacent blade root cover segments 32 are brought together, the complementary mating features 78, 82 can slide relative to each other. In Figure 8 it is shown that the concave mating feature 78 of the first blade root cover segment 32a engages with the convex mating feature 82 of the second blade root cover segment 32b, but it should be realized that Figure 6 in it the two mating features 78, 82 are shown on the same segment.

[0061] The benefits of the complementary mating features 78, 82 are that they help to position and guide two adjacent blade root cover segments 32 into place during assembly. And in particular, during the tensioning process, the mating features 78, 82 ensure that the cover segments 32 are locked together and cannot move out of sync. Another benefit is that the interlocking nature of the adjacent wall edges means that there are no gaps in the blade root cover through which water can pass. Although the illustrated embodiment depicts the currently preferred complementary mating features, it is conceivable that similar effects can be achieved by other means. For example, a type of interlocking connector can be provided on the flange edge for connection to an adjacent flange edge.

[0062] Optionally, and as shown in the illustrated embodiment, the complementary mating features 78, 82 also include a locking system 90 such that once the mating features have engaged beyond a predetermined amount, they are interlocked with each other. This is useful during the assembly process as adjacent vane root cover segments 32 can be locked together in a daisy chain fashion while progressively building the vane root cover assembly.

[0063] As Figures 6 to 8 shown, the locking system in this embodiment includes a pair of locking wedges 92 defined on the convex mating feature 82 and a corresponding pair of locking windows 94 defined on the concave mating feature 82. The locking wedges 92 are oriented such that their shallow inclined surfaces 92a face the adjacent vane root cover segments, while the sharp inclined surfaces 92b face away from the adjacent segments. More or fewer locking wedges 92 can be provided as desired.

[0064] In use, as the convex mating feature 82 is inserted into the concave mating feature 78, the locking wedges 92 force the parallel wall portions 81 apart and form a bayonet fit into the corresponding locking windows 94.

[0065] In accordance with the above discussion, it should be appreciated that the complementary mating features 78, 82 and the tensioning device 48 work together during the assembly of the complete vane root cover to first hold the individual vane root cover segments 32 together, but also apply tension between the segments in order to force the vane root cover 30 to contract onto the vane and thus be held firmly in place. As Figure 3 shown, once the vane root cover 30 is in place to cover the gap between the vane root 24 and the vane hole in the fairing, water ingress into the hub can be reliably prevented. In a further enhanced aspect, the vane root cover 30 is equipped with a sealing device that includes an integral surface seal 96 that is configured to seal against the vane surface when the vane root cover is in place.

[0066] As Figure 7Best shown, the surface seal 96 is implemented by a first gasket member and a second gasket member 98. The gasket member 98 is installed in the corresponding groove 100 defined on the lower side of the flange 40 so that when the blade root cover member is installed, these gasket members press against the blade root 24. The corresponding groove 100 and thus also the gasket member 98 extend longitudinally along the flange 40 from the first and second ends of the flange, that is, along the length direction of the flange. When assembling the blade root cover to the blade, the corresponding gasket members 98 of the blade root cover segment 32 form a continuous waterproof seal between the flange 40 and the blade root 24 to prevent water from passing through this path. This is beneficial for known methods involving using curable polymers to seal the blade root cover to the blade. Although two gasket members are shown in the illustrated embodiment, it is conceivable that a single gasket member can also be effective.

[0067] Although the tensioning device 48 discussed above is envisioned to be sufficient to fix the assembled blade root cover 30 to the blade, as a further measure, one or more of the blade root cover segments can be provided with additional fixing means 102. This is shown Figure 6 in the form of holes 104 which define a path through which a suitable fastener can pass to be screwed into the blade. As shown here, the hole 104 is a relatively flat block protruding outward from the flange 40 along the plane of the flange 40. Optionally, a suitable mounting point (such as a polymer block) can be molded into the blade to serve as a sacrificial screw point in the blade, thus avoiding possible damage to the composite material of the blade skin.

[0068] It is conceivable that a similar solution can be provided by bonding the mounting block to the blade, for example, using a liquid adhesive or double-sided tape, where the hole 104 has suitable configurable variations. However, instead of the hole 104, a clamping member in the form of a plate (not shown) can be used to attach to the mounting block and traverse the cover segment to apply a downward and / or lateral force to the cover segment as an additional measure to hold the cover segment in place. Adjustment in the circumferential direction and the span direction can be provided. With this solution, drilling in the blade can be avoided.

[0069] Figures 9a to 9f A method of assembling the blade root cover 30 according to the above embodiment is shown. It should be realized that the modular nature of the blade root cover 30 of the present invention facilitates a particularly convenient step-by-step assembly process. In Figure 9aIn [description], it is shown that a single blade root cover segment 110 is provided to the blade root 24. This blade root cover portion is attached to a tether or rope 112 that is suspended above the top of the blade root 24. The rope 112 can be fixed to a suitable stop or support 113 (such as a winch (not shown)), or simply held in the hand of an assembly worker (not shown). Then, the blade root cover segment 110 can be pulled by the rope 112 to place the blade root cover segment in a higher position on the blade root 24. At this time, a second blade root cover segment 114 can be provided upward to the blade root and fixed to the first blade root cover segment 110. This is shown in Figure 9b At this point, the complementary mating features 78, 82 of the blade root cover segments 110, 114 will engage with each other, and the bracket 58 can also be fixed by the adjuster 70 (as discussed above), although this detail is not shown in Figures 9a to 9f In [description]. Figure 9c And Figure 9d show the continuation of this process of gradually building up the blade root cover by adding more and more blade root cover segments (shown here as 116 and 118). The control of the partially assembled blade root cover can be maintained by appropriate tension on the rope 112. Figure 9e shows the complete blade root cover 30. At this time, the adjusters 70 spanning the respective pairs of blade root cover segments can be loosely adjusted so that the blade root cover 30 can be correctly positioned. Possibly, most of the adjusters can be fully tightened at this time, conveniently leaving only one or two adjusters to be tightened, so as to place the tension band under sufficient tension to hold the blade root cover tightly in place on the blade root 24. Figure 9f depicts the final tightening of one or more adjusters 70 (as illustrated by the radially inward straight arrows) to achieve a slight radial contraction of the blade root cover 30, thereby fixing the blade root cover to the blade root portion 24.

[0070] Once this is achieved, one or more of the blade root cover segments 32 can be fixed to the blade by suitable fasteners passing through the through-holes 104.

[0071] Figure 10 shows an alternative blade root cover that particularly has variations regarding fastening the blade root cover to the blade and fastening the blade root cover segments to each other. The differences from Figure 6 will be described in more detail below, and items similar to Figure 6 are not highlighted here.

[0072] In Figure 6It is mentioned in [reference] that the additional fixing device 102 can be an eyelet 104 through which a suitable fastener can be screwed into the blade. Alternative options include, for example, a mounting block 204 fixed to the blade by a liquid adhesive or double-sided tape. Below, reference will be made to Figure 11a and Figure 11b to describe the block in more detail.

[0073] In addition, in Figure 6 a single-piece embodiment of the tensioning belt 50 is shown. Below, alternative embodiments of the tensioning belt will be described in detail with reference to FIGS. 11 to Figure 13 . Finally, it should be noted that Figure 6 the web 54 in Figure 10 has also been slightly modified in the embodiment of

[0074] Figure 11a and Figure 11b , that is, two additional webs 210 are introduced in the outermost part. This further strengthens the system. Figure 11b A bracket connecting the two bolts 204a and 205a is also disclosed, and enables front-back and lateral adjustment through the slits in at least one of the said components.

[0075] Similarly, in Figure 10 and FIG. 11, a variant of the tensioning belt 50 can be seen, which includes a plurality of tensioning belt parts 250. In one variant as shown in the figure, two similar tensioning belt parts 250 are positioned at each end of the blade root cover segment, and as best seen in Figure 11a , these tensioning belt parts are connected to each other in the region of the segment block 205. The connection is shown with two bolts 255 on each side of the segment block 205; however, other connecting devices can also be used, and the third belt part can be a central member.

[0076] In Figure 12 , a single tensioning belt part 250 is shown, which includes an inner end 251 showing four holes for connecting to another belt part, as described above. In another outer end 252, the tensioning belt part is shaped to form two loops that serve as part of the connecting device. As seen in Figure 13 , a fixing mechanism 253 can be held between the two loops, and thus in a manner similar to Figure 6 and Figure 8in the same manner as shown, is securely connected to an adjacent blade root cover segment, where brackets are used. Compared with Figure 6 and Figure 8 , Figure 12 the advantages of the design are considered to be that the pulling force from the adjustable tensioning mechanism or "regulator" (similar to the bolts and nuts described in Figure 8 ) is better aligned with the tensioning belt. Note that all parts of the connecting device can be made of steel.

[0077] Those skilled in the art will recognize that various modifications can be made to the illustrated embodiments discussed above without departing from the inventive concept defined by the claims.

[0078] For example, one enhancement to the illustrated embodiments is to provide reinforcing ribs on the cover segment. These reinforcing ribs can be formed in any suitable manner, which will provide increased stiffness to the cover segment in a certain direction. One option is to define such reinforcing ribs on the lower side of the cover segment, for example, between the gasket grooves.

Claims

1. A blade root cover segment (32) adapted to be assembled to a wind turbine blade (14) to span a gap (28) between the blade and a nacelle cover (18), the blade root cover segment (32) extending circumferentially between a first end (44) and a second end (46), and the blade root cover segment comprising: A curved flange (40) for abutting a corresponding curved surface of the wind turbine blade; A cover wall (42) extending from the flange (40); A tension band (50) associated with the flange (40), the tension band (50) extending in the circumferential direction between a first end and a second end, wherein the first end of the tension band (50) is close to the first end (44) of the blade root cover segment (32), and the second end of the tension band (50) is close to the second end (46) of the blade root cover segment (32), and wherein the first end and the second end of the tension band (50) comprise connecting means (56, 58, 70) for connecting to a similar blade root cover segment and applying tension between similar blade root cover segments.

2. The blade root cover segment according to claim 1, wherein, The first end and the second end of the cover wall (42) comprise complementary mating features (78, 82).

3. The blade root cover segment according to claim 2, wherein, The complementary mating features comprise a locking mechanism.

4. The blade root cover segment according to claim 2 or 3, wherein The complementary mating features comprise a convex feature (82) on the first end (76) of the cover wall (42) and a concave feature (78) on the second end (80) of the cover wall (42).

5. The blade root cover segment according to claim 1, wherein, The flange (40) comprises sealing means for sealing against the blade surface.

6. The blade root cover segment according to claim 5, wherein, The sealing means comprises at least one gasket member (96).

7. The blade root cover segment according to claim 6, wherein, The gasket member (96) extends along the length of the blade root cover segment.

8. The blade root cover segment according to claim 6 or 7, wherein, The gasket member (96) extends between the first end (44) and the second end (46) of the blade root cover segment (32).

9. The blade root cover segment according to any one of claims 1 to 3, wherein, The tension band (50) is retained on the blade root cover segment (32).

10. The blade root cover segment according to claim 9, wherein, The tension band (50) is retained in a groove (52) in the flange (40) of the blade root cover segment (32).

11. The blade root cover segment according to any one of claims 1 to 3, the blade root cover segment further comprising one or more stiffening webs (54) extending between the flange (40) and the cover wall.

12. The blade root cover segment according to claim 11, wherein, The one or more stiffening webs (54) retain the tension band (50) on the blade root cover segment (32).

13. The blade root cover segment according to any one of claims 1 to 3, wherein, The connecting means (56) of the tension band (50) comprises a bracket (58) connected to the flange (40).

14. The blade root cover segment according to any one of claims 1 to 3, wherein, The connecting means (56) comprises an adjustable connector (70) configured to connect to an adjacent tension band (50) and adjust the spacing between the tension bands.

15. The blade root cover segment according to any one of claims 1 to 3, wherein, The flange (40) includes holes (104) for fasteners that can pass through the holes to fasten the flange (40) to the blade.

16. The blade root cover segment according to any one of claims 1 to 3, wherein, The tension band is formed of a material having a tensile strength higher than that of the materials forming the flange (40) and the cover wall (42).

17. The blade root cover segment according to any one of claims 1 to 3, wherein, The tension band is a single component for each blade root cover segment.

18. The blade root cover segment according to any one of claims 1 to 3, wherein, The tension band includes a plurality of portions for each blade root cover segment.

19. The blade root cover segment according to any one of claims 1 to 3, wherein, The cover wall (42) and the flange (40) are made of plastic.

20. The blade root cover segment according to any one of claims 1 to 3, wherein The cover wall and the flange are injection molded as a single article.

21. A blade root cover (30) comprising a plurality of blade root cover segments (32) according to any one of claims 1 to 20 connected end to end in a ring.

22. A method for mounting a blade root cover (30) on a wind turbine blade, wherein, The blade root cover includes a plurality of separate and connectable blade root cover segments (32) according to claim 1, the method including the steps of: Supporting a first blade root cover segment (32; 110) on the blade (24), Forming a blade root cover assembly by providing a second blade root cover segment (32; 114) to a position adjacent to the first blade root cover segment (32; 110) on the blade and connecting the second blade root cover segment (32; 114) to the first blade root cover segment (32; 110) using the connecting means (56) of each respective blade root cover segment, Connecting additional blade root cover segments (32; 116, 118) to the blade root cover assembly of the first and second blade root cover segments to increase the circumferential length of the blade root cover assembly until a complete blade root cover is formed.

23. The method according to claim 22, wherein, The step of supporting the first blade root cover segment (32; 110) on the blade includes: suspending the first blade root cover segment (32; 110) from a support member (113) that is separate from the blade.

24. The method according to claim 23, wherein, The step of suspending the first blade root cover segment (32; 110) includes: extending a rope (112) from the first blade root cover segment (32; 110) above the upper part of the blade root to the support member (113).

25. The method according to any one of claims 22 to 24, the method further comprising the steps of: While connecting the additional blade root cover segments (32: 114, 116, 118) to the blade root cover assembly, moving the first blade root cover segment (32; 110) in a stepwise manner.

26. The method according to any one of claims 22 to 24, the method further comprising the steps of: When the complete blade root cover has been assembled, applying circumferential tension to the blade root cover through the connecting means.

27. The method according to any one of claims 22 to 24, the method further comprising the steps of: Fixing one or more of the blade root cover segments to the blade using corresponding blade fastening components.

28. A wind turbine generator, the wind turbine generator comprising a nacelle, the nacelle being rotatably supported to a hub including at least one blade, wherein, The blade includes a blade root cover according to claim 21.

29. The wind turbine generator according to claim 28, wherein, The blade root cover is attached to the blade by one or more fasteners penetrating the blade.

30. The wind turbine generator according to claim 29, wherein, The one or more fasteners penetrate into fixing blocks embedded in the blade, and the fixing blocks are made of a material different from that of the blade.

31. The wind turbine generator according to claim 28, wherein, The blade root cover is attached to the blade by using a liquid adhesive or double-sided tape.

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