WIND TURBINE ROTOR BLADE WITH COVERED ACCESS WINDOW

Abstract

The present invention relates to a wind turbine blade with an access window extending through the blade. A cover member for covering the access window is provided, such that a first end of the cover member is pivotally connected to the outer surface of the blade and a second end of the cover member is releasably fastened to the outer surface of the blade.

Claims

1. A wind turbine blade, comprising: a profiled contour comprising a pressure side and a suction side, and a leading edge and a trailing edge with a chord having a chord length extending therebetween, the wind turbine blade extending in a spanwise direction between a root end and a tip end; an outer surface; an access window extending through the wind turbine blade; and a cover member for covering the access window, wherein a first end of the cover member is pivotally connected to the outer surface of the wind turbine blade and a second end of the cover member is releasably fastened to the outer surface of the wind turbine blade.

2-20. (canceled)

21. The method of claim 1, wherein the cover member substantially flushes with the outer surface of the wind turbine blade.

22. The method of claim 1, wherein the first end of the cover member is hinged to the outer surface of the wind turbine blade.

23. The method of claim 1, wherein the second end of the cover member is releasably fastened to the outer surface of the wind turbine blade through a fastening mechanism.

24. The method of claim 23, wherein the fastening mechanism comprises a male fastening member and a female fastening member.

25. The method of claim 23, wherein the cover member is configured to cover the fastening mechanism in a closed position of the cover member.

26. The method of claim 23, wherein the fastening mechanism is a push-latch mechanism.

27. The method of claim 23, wherein the fastening mechanism is a twist-latch mechanism.

28. The method of claim 23, wherein the fastening mechanism is a magnetic latch.

29. A method of manufacturing a wind turbine blade having a profiled contour including a pressure side and a suction side, and a leading edge and a trailing edge with a chord having a chord length extending therebetween, the wind turbine blade having an outer surface extending in a spanwise direction between a root end and a tip end, the method comprising: cutting an access window through the wind turbine blade; pivotally connecting a first end of a cover member to the outer surface of the wind turbine blade; and releasably fastening a second end of the cover member to the outer surface of the wind turbine blade to cover the access window.

30. A method of manufacturing a wind turbine blade, the method comprising: manufacturing a pressure side shell half and a suction side shell half; arranging a spar structure within the pressure side shell half or within the suction side shell half, the spar structure comprising a first part and a second part, the first and second part being releasably coupled to each other; cutting an access window through the suction side shell half or the pressure side shell half; pivotally connecting a first end of a cover member to the outer surface of the wind turbine blade; releasably fastening a second end of the cover member to the outer surface of the wind turbine blade to cover the access window; joining the pressure side shell half and the suction side shell half for obtaining a closed shell body; cutting the closed shell body along a cutting plane substantially normal to the spanwise direction of the closed shell body to obtain a first blade segment and a second blade segment, each of the first and second blade segments comprising part of the pressure side shell half and part of the suction side shell half, wherein the spar structure extends across the cutting plane; uncoupling the first and second part of the spar structure; separating the first blade segment from the second blade segment; and joining and sealing the first blade segment to the second blade segment for obtaining the wind turbine blade; wherein the spar structure comprises at least one locking pin for releasably coupling the first part to the second part of the spar structure through aligned respective locking apertures in each of the first and second part of the spar structure.

31. The method of claim 30, wherein uncoupling the first and second part of the spar structure comprises withdrawing the locking pin from the aligned respective apertures in each of the first and second part of the spar structure via the access window.

32. The method of claim 30, further comprising re-inserting the locking pin into the aligned respective apertures in each of the first and second part of the spar structure via the access window, after joining and sealing the first blade segment to the second blade segment.

33. The method of claim 30, wherein the cover member is flush with the outer surface of the wind turbine blade.

34. The method of claim 30, wherein the first end of the cover member is hinged to the outer surface of the wind turbine blade.

35. The method of claim 30, wherein the second end of the cover member is releasably fastened to the outer surface of the wind turbine blade through a fastening mechanism.

36. The method of claim 30, wherein the cover member is configured to cover the fastening mechanism in a closed position of the cover member.

37. The method of claim 30, wherein the fastening mechanism is a push-latch mechanism.

38. The method of claim 30, wherein the fastening mechanism is a twist-latch mechanism.

39. The method of claim 30, wherein the fastening mechanism is a magnetic latch.

Description

DESCRIPTION OF THE INVENTION

[0073] The invention is explained in detail below with reference to an embodiment shown in the drawings, in which

[0074] FIG. 1 shows a wind turbine,

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

[0076] FIG. 3 shows a schematic view of a cross-section of a wind turbine blade,

[0077] FIG. 4 is a schematic cut-open view of a wind turbine blade,

[0078] FIG. 5 is an enlarged view of the encircled section in FIG. 4, and

[0079] FIGS. 6, 7 and 8 are perspective views of a spar structure,

[0080] FIG. 9 is a partial perspective view of an access opening of a wind turbine blade,

[0081] FIG. 10 is a perspective partial view of a wind turbine rotor blade,

[0082] FIG. 11 is a front partial view of a wind turbine rotor blade according to the present invention, wherein push latch mechanism is employed as a fastening mechanism to fasten cover member to the blade,

[0083] FIG. 12 is a front partial view of a wind turbine rotor blade according to the present invention, wherein magnetic latch is employed as a fastening mechanism to fasten cover member to the blade, and

[0084] FIG. 13 and FIG. 14 are front partial views of a wind turbine rotor blade according to the present invention, wherein twist latch mechanism is employed as a fastening mechanism to fasten cover member to the blade.

DETAILED DESCRIPTION

[0085] FIG. 1 illustrates a conventional modern upwind wind turbine according to the so-called “Danish concept” with a tower 4, a nacelle 6 and a rotor with a substantially horizontal rotor shaft. The rotor includes a hub 8 and three blades 10 extending radially from the hub 8, each having a blade root 16 nearest the hub and a blade tip 14 farthest from the hub 8. The rotor has a radius denoted R.

[0086] FIG. 2 shows a schematic view of a wind turbine blade 10. The wind turbine blade 10 has the shape of a conventional wind turbine blade and comprises a root region 30 closest to the hub, a profiled or an airfoil region 34 farthest away from the hub and a transition region 32 between the root region 30 and the airfoil region 34. The blade 10 comprises a leading edge 18 facing the direction of rotation of the blade 10, when the blade is mounted on the hub, and a trailing edge 20 facing the opposite direction of the leading edge 18.

[0087] The airfoil region 34 (also called the profiled region) has an ideal or almost ideal blade shape with respect to generating lift, whereas the root region 30 due to structural considerations has a substantially circular or elliptical cross-section, which for instance makes it easier and safer to mount the blade 10 to the hub 8. The diameter (or the chord) of the root region 30 may be constant along the entire root area 30. The transition region 32 has a transitional profile gradually changing from the circular or elliptical shape of the root region 30 to the airfoil profile of the airfoil region 34. The chord length of the transition region 32 typically increases with increasing distance r from the hub 8. The airfoil region 34 has an airfoil profile with a chord extending between the leading edge 18 and the trailing edge 20 of the blade 10. The width of the chord decreases with increasing distance r from the hub.

[0088] A shoulder 40 of the blade 10 is defined as the position, where the blade 10 has its largest chord length. The shoulder 40 is typically provided at the boundary between the transition region 32 and the airfoil region 34. FIG. 2 also illustrates the longitudinal extent L, length or longitudinal axis of the blade.

[0089] It should be noted that the chords of different sections of the blade normally do not lie in a common plane, since the blade may be twisted and/or curved (i.e. pre-bent), thus providing the chord plane with a correspondingly twisted and/or curved course, this being most often the case in order to compensate for the local velocity of the blade being dependent on the radius from the hub.

[0090] The blade is typically made from a pressure side shell part 36 and a suction side shell part 38 that are glued to each other along bond lines at the leading edge 18 and the trailing edge of the blade 20.

[0091] FIG. 3 shows a schematic view of a cross section of the blade along the line I-I shown in FIG. 2. As previously mentioned, the blade 10 comprises a pressure side shell part 36 and a suction side shell part 38. The pressure side shell part 36 comprises a spar cap 41, also called a main laminate, which constitutes a load bearing part of the pressure side shell part 36. The spar cap 41 comprises a plurality of fibre layers 42 mainly comprising unidirectional fibres aligned along the longitudinal direction of the blade in order to provide stiffness to the blade. The suction side shell part 38 also comprises a spar cap 45 comprising a plurality of fibre layers 46. The pressure side shell part 38 may also comprise a sandwich core material 43 typically made of balsawood or foamed polymer and sandwiched between a number of fibre-reinforced skin layers. The sandwich core material 43 is used to provide stiffness to the shell in order to ensure that the shell substantially maintains its aerodynamic profile during rotation of the blade. Similarly, the suction side shell part 38 may also comprise a sandwich core material 47.

[0092] The spar cap 41 of the pressure side shell part 36 and the spar cap 45 of the suction side shell part 38 are connected via a first shear web 50 and a second shear web 55. The shear webs 50, 55 are in the shown embodiment shaped as substantially I-shaped webs. The first shear web 50 comprises a shear web body and two web foot flanges. The shear web body comprises a sandwich core material 51, such as balsawood or foamed polymer, covered by a number of skin layers 52 made of a number of fibre layers. The blade shells 36, 38 may comprise further fibre-reinforcement at the leading edge and the trailing edge. Typically, the shell parts 36, 38 are bonded to each other via glue flanges.

[0093] FIG. 4 is a schematic cut-open, exploded view of a wind turbine blade according to a co-pending application of the present applicant, wherein FIG. 5 is an enlarged view of the encircled section in FIG. 4. A pressure side shell half and a suction side shell half are typically manufactured over the entire length L of the wind turbine blade 10. A spar structure 62 is arranged within the shell. The spar structure 62 comprising a first part 64 and a second part 66 [as shown in FIG. 5], the first and second part being releasably coupled to each other, as shown in FIG. 8. The method advantageously comprises fixing the first part 64 of the spar structure 62 to one or both of the shell halves within the first blade segment 68 and fixing the second part 66 of the spar structure to one or both of the shell halves within the second blade segment 70.

[0094] The shell halves are then closed and joined, such as glued together for obtaining a closed shell, which is subsequently cut along a cutting plane 69 substantially normal to the spanwise direction or longitudinal extent of the blade to obtain a first blade segment 68 and a second blade segment 70. The cutting plane 69 coincides with an end surface 65 of the first part 64 of the spar structure.

[0095] As seen in FIGS. 4 and 5, the spar structure 62 extends across the cutting plane 69. As best seen in FIG. 5, the first part 64 of the spar structure 62, which takes the form of a box-shaped sheath member for at least partly enclosing the second part 66 of the spar structure in the illustrated embodiment, is fixed to the first blade segment 68. The second part 66 of the spar structure 62, which comprises a spar box in the illustrated embodiment, is fixed to the second blade segment 70, wherein the second part 66 extends beyond the second blade segment 70 into the first blade segment 68, when the blade segments are assembled.

[0096] FIG. 5 also illustrates an access opening 80 within the upper half of the illustrated shell for accessing the spar structure and coupling and uncoupling the first and second part of the spar structure 62. For uncoupling, a locking pin, as illustrated in FIGS. 6-8, is withdrawn from the aligned respective apertures 76, 78 in each of the first and second part of the spar structure via the access opening 80. Prior to, or after, joining and sealing the first blade segment 68 to the second blade segment 70 for obtaining the wind turbine blade, the method advantageously comprises re-coupling the first and second part of the spar structure, via the access opening 80, as illustrated in FIG. 8, by re-inserting the locking pin 74 into the aligned respective apertures 76, 78 in each of the first and second part of the spar structure. As seen in FIGS. 4 and 5, the cutting step dl) does not comprise cutting the spar structure, only the shell halves are cut. In addition, two shear webs 82a, 82b are arranged within the first blade segment.

[0097] FIGS. 6, 7 and 8 illustrate an embodiment of the spar structure 62 with the first part 64 in the form of a conductive, box-shaped sheath member according to a co-pending application of the present applicant. Preferably, the conductive sheath member is part of a lightning protection system of the wind turbine blade. The second part 66 of the spar structure comprises a box spar 67, part of which is encased in a jacket 72, for example comprising a conductive mesh 72. The spar structure 62 comprises a locking pin 74 for releasably coupling the first part 64 to the second part 66 of the spar structure through aligned respective locking apertures 76, 78 in each of the first and second part of the spar structure.

[0098] FIG. 9 is a partial perspective view of an access opening 180 of a wind turbine blade 10. The wind turbine blade 10 comprises a shell member 138, such as a suction side shell half, with an outer surface 110. The shell member 138 may comprise a first segment 168, such as a root end segment, connected to a second segment 170, such as a tip end segment. An access opening 180 is provided in the blade shell member 138 for allowing access to a hollow space within the blade, e.g. for inserting or withdrawing a locking pin 174 as described above.

[0099] FIG. 10 is a partial perspective view of a wind turbine rotor blade 10 with an outer surface 110, here illustrating the outer surface of a suction side shell half 138. In manufacturing the blade of the present invention, an access window 94 is cut through the blade for allowing access to the interior thereof, as indicated by the hatched line in FIG. 10. In the illustrated example of FIG. 10, the access window is substantially rectangular and is provided close to the trailing edge of the blade.

[0100] As illustrated in FIG. 11, a cover member 92 is configured to cover the access window 94. The cover member 92 comprises a first end 92a and a second end 92b. The first end 92a is pivotally connected to the outer surface 110 of the blade 10 and the second end 92b is releasably and self-engagingly fastened to the outer surface 110 of the blade 10 through a fastening mechanism. In one embodiment of the invention, the fastening mechanism may be a self-engaging and externally releasable fastening mechanism. The cover member 92 is capable of pivotally moving between an open position and a closed position relative to the blade 10. In the open position of the cover member 92, the interior of the blade 10 may be accessed through the access window 94, and in the closed position, the cover member 92 substantially flushes with the outer surface 110 of the blade 10. The fastening mechanism includes but not limited to push latch mechanism 95 as shown in FIG. 11. The push latch mechanism 95 includes a male fastening member 93a and a female fastening member 93b. The push latch mechanism 95 is an exemplary mechanism that typically opens upon receiving an input force to unlock and subsequently an input force from the same direction locks the mechanism. In the locked or closed position, the male fastening member 93a is self-engagingly accommodated in the female fastening member 93b. In an exemplary embodiment of the push latch mechanism 95 shown in FIG. 11, the female fastening member 93a is a ball mounted on an inner surface of the cover member 92. The ball latches and releases from the hook provisioned on the outer surface 110 of the blade 10 based on the position and the external input force applied on the cove member 92 between open and closed positions.

[0101] The second end 92b of the cover member 92 is self-engagingly fastened to the outer surface 110 of the blade 10. In other words, that there is no requirement of any external member or tool for fastening the cover member 92 with the blade 10. The fastening mechanism of the present invention is self-reliant or self-engaged in that it allows the male fastening member 93a to engage with the female fastening member 93b without having to use any external tool and to remain engaged until an external disengaging force is applied.

[0102] For instance, considering push-latch mechanism 95 as an exemplary fastening mechanism, a push force applied on the external surface of the cover member 92 towards the blade 10 causes engagement between the male fastening member 93a and the female fastening member 93b and hence eliminates the requirement of external members such as screw, nut and bolt etc.

[0103] Further, the fastening mechanism is externally releasable, in that the fastening mechanism may be disengaged by external operation. Considering the exemplary push-latch mechanism 95, external input force on the cover member 92 proximal to second end 92a causes release or dis-engagement of the cover member 92 from the blade 10. This eliminates the need for using either manual or powered tools to operate the cover member between the closed position and the open position.

[0104] As illustrated in FIG. 12, in another exemplary embodiment of the invention, the fastening mechanism is a magnetic latch 97. The magnetic latch 97 is a system of magnets that can either attach directly and self-engagingly to another magnetic structure or will move when the magnets are nearby. A first magnet 93a may be mounted on the inner surface of the cover member 92 and a second magnet 93b may be attached to the outer surface 110 of the blade 10 proximal to access window 94. The first magnet 93a and the second magnet 93b of opposite polarity may be attracted to each other to bring the cover member 92 to a self-engagingly closed position. Further, a magnet of same polarity may induce repulsive force to move the cover member 92 away from the closed position.

[0105] As in case of the push-latch mechanism 95, the exemplary magnetic latch 97 allows self-engagement between the cover member 92 and the blade 10. The magnetic latch 97 is externally releasable as well using a suitable technique. A magnet of one polarity may be provisioned on an inner surface of the cover member 92 at its second end 92b, this acts as a male fastening member 93a. Further, a magnet of opposite polarity or a member having magnetic properties may be provisioned in the blade 10, to act as a female fastening member 93b. As the cover member 92 is moved towards the blade 10, the male fastening member 93a engages with the female fastening member 93b, and remains engaged until an external disengaging force is applied and hence eliminates the requirement of external members such as screw, nut and bolt etc.

[0106] Further, the magnetic latch may be externally releasable by means such as introducing magnetic member of polarity same as that of the male fastening member 93a provisioned on the cover member 92. This may create repulsive force and thus causes release of the cover member 92. This eliminates the need for using tools either manual or powered, to operate the cover member between the closed position and the open position.

[0107] As illustrated in FIG. 13 and FIG. 14, in yet another exemplary embodiment of the invention, the self-engaging and externally releasable fastening mechanism is twist latch mechanism 96. The twist latch mechanism 96 refers to a mechanism that typically remains flush with the outer surface when not in use, as shown in FIG. 13, but can be opened up by an externally applied twist force which allows movement from the closed position towards the open position as shown in FIG. 14. The twist latch mechanism 96 includes a threaded fastening member which may unfasten when twisted facilitating opening of the cover member 92.

[0108] As in case of push-latch mechanism 95 and the magnetic latch 97, the twist latch mechanism 96 allows self-engagement between the cover member 92 and the blade 10. The twist latch mechanism 96 is externally releasable as well. The twist-latch mechanism 97 may include a knob-like member, which may be turned in clockwise direction to cause engagement and in anti-clockwise direction to unlock or disengage. Thus, the cover member 92 and the blade 10 may be self-engaged by twisting the knob-like structure in clockwise direction and may be externally released by twisting in the antic-clockwise direction. This eliminates the requirement of external members such as screw, nut and bolt etc.

[0109] In some embodiments, there may be other self-engaging and externally releasable fastening mechanisms that may be employed apart from the above. Other such self-engaging and externally releasable fastening mechanisms may include but are not limited to snap lock, detent lock etc and the same should be construed as part of the present invention.

[0110] The invention is not limited to the embodiments described herein and may be modified or adapted without departing from the scope of the present invention.

[0111] A technical contribution for the disclosed wind turbine blade and method of manufacturing the same is that it improves access opening and closing and engaging arrangement.

[0112] According to one embodiment of the invention, there is provided a wind turbine blade having a profiled contour including a pressure side and a suction side, and a leading edge and a trailing edge with a chord having a chord length extending therebetween, the wind turbine blade extending in a spanwise direction between a root end and a tip end, wherein the blade comprises an outer surface, an access window extending through the blade, a cover member for covering the access window, wherein a first end of the cover member is pivotally connected to the outer surface of the blade and a second end of the cover member is releasably fastened to the outer surface of the blade.

[0113] According to another embodiment of the invention, there is provided a method of manufacturing a wind turbine blade having a profiled contour including a pressure side and a suction side, and a leading edge and a trailing edge with a chord having a chord length extending therebetween, the wind turbine blade extending in a spanwise direction between a root end and a tip end, wherein the blade comprises an outer surface, the method comprising the steps of: cutting an access window through the blade, pivotally connecting a first end of a cover member to the outer surface of the blade, and releasably fastening a second end of the cover member to the outer surface of the blade to cover the access window.

[0114] According to yet another embodiment of the invention, there is provided a method of manufacturing a wind tur-bine blade according to the present invention, the method comprising the steps of: manufacturing a pressure side shell half and a suction side shell half, arranging a spar structure within the pressure side shell half or within the suction side shell half, the spar structure comprising a first part and a second part, the first and second part being releasably coupled to each other, cutting an access window through the suction side shell half or the pressure side shell half, preferably the suction side shell half, pivotally connecting a first end of a cover member to the outer surface of the blade, releasably fastening a second end of the cover member to the outer surface of the blade to cover the access window, joining the pressure side shell half and the suction side shell half for obtaining a closed shell body, cutting the closed shell body along a cutting plane substantially normal to the spanwise direction of the closed shell body to obtain a first and a second blade segment, each blade segment comprising part of the pressure side shell half and part of the suction side shell half, wherein the spar structure extends across the cutting plane, uncoupling the first and second part of the spar structure, separating the first blade segment from the second blade segment, joining and sealing the first blade segment to the second blade segment for obtaining the wind turbine blade, wherein the spar structure comprises at least one locking pin for releasably coupling the first part to the second part of the spar structure through aligned respective locking apertures in each of the first and second part of the spar structure.

[0115] While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Further, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not limited by the foregoing description, but is only limited by the scope of the appended claims.

LIST OF REFERENCE NUMERALS

[0116] 4 tower [0117] 6 nacelle [0118] 8 hub [0119] 10 blade [0120] 14 blade tip [0121] 16 blade root [0122] 18 leading edge [0123] 20 trailing edge [0124] 30 root region [0125] 32 transition region [0126] 34 airfoil region [0127] 36 pressure side shell part [0128] 38, 138 suction side shell part [0129] 40 shoulder [0130] 41 spar cap [0131] 42 fibre layers [0132] 43 sandwich core material [0133] 45 spar cap [0134] 46 fibre layers [0135] 47 sandwich core material [0136] 50 first shear web [0137] 51 core member [0138] 52 skin layers [0139] 55 second shear web [0140] 56 sandwich core material of second shear web [0141] 57 skin layers of second shear web [0142] 60 filler ropes [0143] 62 spar structure [0144] 64 first part [0145] 65 end surface of first part [0146] 66 second part [0147] 67 spar member [0148] 68,168 first blade segment [0149] 69 cutting plane [0150] 70,170 second blade segment [0151] 72 jacket/mesh [0152] 74,174 locking pin [0153] 76 aperture [0154] 78 aperture [0155] 80,180 access opening [0156] 82 shear web [0157] 90 access arrangement [0158] 92 cover member [0159] 92a first end of the cover member [0160] 92b second end of the cover member [0161] 93a male fastening member [0162] 93b female fastening member [0163] 94 access window [0164] 95 push-latch mechanism [0165] 96 twist-latch mechanism [0166] 97 magnetic latch [0167] 110 outer blade surface [0168] L length [0169] r distance from hub [0170] R rotor radius