Wind turbine blade, ladder support assembly, wind turbine, and method for accessing the interior of a hollow blade of a wind turbine

Abstract

A wind turbine blade including a hollow blade body having a blade root and a base plate disposed at a root end of the blade, the base plate including a manhole allowing access to an interior of the blade, the base plate being provided with attachment means disposed at or near the manhole and configured to directly or indirectly attach at least one ladder to the base plate.

Description

[Technical Field]

[0001] The present invention relates to a method for accessing the interior of a hollow blade of a wind turbine, the blade being attached to a rotatable hub of the wind turbine, the interior of the blade being accessible from the hub area through a manhole in a base plate at the root end of the blade, and more particularly to a ladder support assembly and a wind turbine. [Background technology]

[0002] To increase maximum energy output, wind turbines are being built larger. Offshore wind turbines, in particular, now have rotor blades with root diameters of 3 to 8 meters, sometimes even larger. Consequently, the root end of the blade also has an inner diameter that exceeds the size of an operator, and therefore has a portion outside the reach of an operator standing inside the hollow blade.

[0003] Depending on the type of blade, it may be necessary to enter the blade from time to time, for example to perform maintenance routines or repair procedures inside the blade. It is therefore known to provide manholes in the blade base plate that allow personnel to enter the interior of the hollow blade. However, particularly for larger blades, depending on the orientation of the blade or rotor, the manhole may be at a height that is inaccessible to personnel, thereby preventing them from accessing the section of the blade that lies behind the base plate.

[0004] Generally, the location of a manhole relative to the access point to the hub can be changed by rotating the wind turbine rotor, so that the manhole can be located in an accessible position. However, locating the rotor blade in such a position may limit the area of ​​the blade interior that is accessible to workers. For example, if the blade diameter is 3 m or more, the location where the manhole can be accessed through the manhole may not allow workers to reach all sections of the blade interior.

[0005] This can lead to problems depending on the position of the blade: either the manhole is inaccessible to workers, making it impossible to access the blade through the manhole, or even if the blade is accessible through the manhole, not all sections of the inner surface are in the direction of access for a worker standing inside the blade. Since it is desirable that all sections of the inner surface of the blade are accessible to perform maintenance procedures, it is necessary to make the blade accessible at various rotor positions. Summary of the Invention

[0006] The invention is based on the object of providing an improved method for accessing the interior of a hollow blade of a wind turbine.

[0007] According to the invention, this problem is solved firstly by the method described below, which comprises: placing the blade in a first position; In this first position, the manhole is accessible to workers from a foothold inside the hub, which remains stationary while the hub rotates; attaching a ladder support assembly to the base plate at or near at least one edge of the manhole; placing the blade in a second position by rotating the hub; In this second position, the distance between the manhole and the footing is greater than in the first position, and mounting at least one ladder to the ladder support assembly for accessing the interior of the blade.

[0008] In a first step, the blade is positioned in a first position to allow access to the manhole by a worker standing on a scaffold inside the hub. The blade can be positioned in the first position by actively rotating the rotor so that the entering blade is in the first position. Alternatively, for example, the rotating rotor can be braked to stop the rotor so that the entering blade is in the first position.

[0009] The blade to be entered has a base plate at its root end, which separates the interior of the hollow blade from the interior of the hollow hub. A manhole is provided in the base plate to allow access to the interior of the blade. The manhole may be, for example, circular or rectangular, and is sized to allow an operator to enter the blade. A circular manhole may have a diameter of, for example, 50 cm to 1 m, while a rectangular or square manhole may have an edge length of, for example, 40 cm to 1 m.

[0010] In the first position, the manhole is accessible to workers from the footing inside the hub. Accessible in this case means that a worker can reach the manhole, particularly the entire circumference, while standing on the footing. Therefore, the distance between the top or apex of the manhole and the footing is 1.5 m or less. This allows a worker to reach the manhole without hindrance while standing on the footing. The footing can be fixed to the nacelle or other stationary support structure of the wind turbine, for example, so as not to rotate when the wind turbine rotor rotates or when the blades rotate around the central axis of the hub.

[0011] When the blade is in the first position, the rudder support assembly is attached to the base plate. The rudder support assembly is attached at least to the edge of the manhole or immediately adjacent to the edge of the manhole. The rudder support assembly can be attached to the base plate, for example, by bolting the rudder support assembly to each opening in the base plate. The manhole can initially be covered with a cover, which is removed before attaching the rudder support assembly to the manhole. The bolt holes used to secure the cover can also be used to secure the rudder support assembly to the base plate.

[0012] The rudder support assembly is attached to the blade in a first position but is not yet used to enter the blade. Once the blade is in the first position, the rudder support assembly can be attached to the base plate without any obstruction, meaning it can be installed in a position that is easily accessible to operators. Naturally, as the rotor blade rotates from the first position to the second position, the rudder support assembly also changes position. Therefore, the rudder support assembly is already attached for the subsequent second blade position, allowing the rudder to be properly secured when the rotor blade rotates to the second position.

[0013] After the ladder support assembly is attached to the base plate, the blade to be entered is placed in a second position by rotating either the hub or the rotor of the wind turbine blade. In the second position, the manhole and the footing are farther apart than in the first position. Specifically, the distance between the manhole and the footing may be such that a worker standing on the footing cannot reach the manhole. For example, the distance between the lower edge of the manhole and the footing in the second position may be 1.5 m or more, particularly 2 m or more. In the second position, at least one ladder is attached to the ladder support assembly to access the interior of the blade. After the ladder is attached to the ladder support assembly, a worker can use the ladder to enter the blade from the manhole.

[0014] The solution according to the invention has the advantage that in the second position it is possible to use the ladder to enter the interior of the hollow blade, even if the manhole is located so far from the footing that the worker cannot enter without using the ladder.

[0015] By placing the blade in the first position, the ladder support assembly can be installed without interfering with the manhole in the blade. For example, if maintenance procedures must be performed on the entire inner surface of the blade, workers can enter the blade in the first position and perform the respective maintenance or repair procedures in the areas accessible in the first position.

[0016] After the blade is rotated to the second position, the blade's orientation relative to the stationary footing changes, and the area of ​​the blade's inner surface accessible to the operator changes. Specifically, for example, if the blade is rotated 180 degrees, the area that was below the blade in the first position becomes above the blade in the second position, and vice versa.

[0017] The method of the present invention has the advantage that by installing the ladder support assembly at the first blade position, the ladder can be installed on the ladder support assembly at the second blade position, allowing safe access to the blade. Furthermore, installation of the ladder is simplified because the ladder can be installed at the second blade position, already in the correct orientation for manhole entry. Another advantage is that it avoids the tedious and difficult task of installing the ladder upside down at the first blade position.

[0018] In particular, the method may be carried out on blades with a root diameter of 2 m or more, in particular 3 m or more or 5 m or more. For example, the root diameter of a wind turbine blade may be between 2 m and 15 m, in particular 3 m to 8 m.

[0019] The method according to the present invention has the additional advantage that it is not necessary to pitch the blades to change the position of the manholes relative to the footing inside the hub. Normally, pitching the turbine blades by approximately 90° allows the manholes in the blade base plate to be repositioned relative to the stationary footing. However, because the rotor is stopped during maintenance procedures, the blades are usually pitched to a parking position, where the rotor is not subjected to any, or at least not significantly, forces from the wind acting on the front side of the rotor. This is undesirable, since the method according to the present invention also has the advantage that the blades can be moved to a different position, avoiding blade pitching and thus the generation of undesirable loads on wind turbine components, particularly the main bearings, shaft, and brakes used to secure the rotor.

[0020] Access to various sections of the inner surface of a wind turbine blade may be required, for example, to check the condition of the blade's shell and / or to perform repair procedures, for example, on the upper and lower sides of the webs that run through the interior of the blade. Also, certain sensors, such as LOPC sensors, may need to be accessed frequently during maintenance procedures. Such sensors may be positioned, for example, at the 3, 6, 9, and 12 o'clock positions around the essentially circular root portion of the wind turbine blade. On larger blades, a sensor positioned at the 12 o'clock position may be inaccessible to a worker standing on the underside of the blade, i.e., at the 6 o'clock position. According to the method of the present invention, the sensor at the 12 o'clock position can be reached using a ladder and ladder support assembly when the blade is positioned in the second position.

[0021] Preferably, in the first position the blade is oriented at an angle of 90° to 120°, in particular an angle of 105°, relative to the vertically upward position of the blade, and / or in the second position the blade is oriented vertically upward or at an angle of 255° to 285°, in particular an angle of 270°.

[0022] The vertically upward position of the blade corresponds, for example, to a position of 0°. The angle between the vertically upward and the position of the blade can be measured in either a clockwise or counterclockwise direction, depending, for example, on the position of the manhole or the eccentric offset of the manhole relative to the center point of the base plate.

[0023] In a preferred embodiment of the invention, the ladder support assembly is mounted at least at or near the upper edge of the manhole in the blade's first position, and when the blade is rotated to the other side of the hub, the ladder support assembly is positioned at the lower end of the manhole, allowing easy access to the blade using a ladder attached to the ladder support assembly, particularly when the entering blade has rotated approximately 180°.

[0024] Preferably, the ladder support assembly includes at least one frame- or plate-shaped, particularly ring- or split-ring-shaped, support segment attached to the base plate so as to at least partially surround the manhole. The support segment allows for attachment of another component of the ladder support assembly to the manhole, particularly perpendicular to the opening. The ladder attached to the ladder support assembly when the blade is rotated to the second position can be attached directly to the support segment or to another component of the ladder support assembly that is attached to the support segment when the blade is in the first position.

[0025] Preferably, the ladder support assembly includes at least one platform segment. The ladder support assembly is positioned at the manhole such that the platform segment extends through the manhole and / or is positioned below the manhole when the blade is in the second position. In particular, the platform segment can be used to rotate the blade to a second position that is different from the vertical orientation of the rotating blade. The platform segment facilitates passage of an operator through the manhole, for example, by walking or crawling on the platform segment.

[0026] Other (further) components of the ladder support assembly may be attached to the platform segment, such as one or more handrails and / or one or more support posts, which support the platform segment relative to the support segment and / or the base plate. The platform segment may include one or more mountings for securing one or more ladders, or one or more mountings may be attached to the platform segment. These components are attached at a first blade position and their orientation is adjusted to be appropriately used when the incoming blade rotates to a second position.

[0027] In a preferred embodiment, at least one ladder is hung on the ladder support assembly. When the rotor blades rotate to the second position, one ladder can be attached to the ladder support assembly by hanging it on the ladder support assembly, particularly by hanging it on a mounting portion of the ladder support assembly. The mounting portion can include, for example, one or more hooks to which the top portion of the ladder can be attached. Alternatively, the ladder can include one or more hooks at its top that engage with corresponding portions on the mounting portion of the ladder support assembly. After being attached to the ladder support assembly, the ladder can be secured by at least one locking mechanism and / or one or more fastening means, such as bolts.

[0028] The ladder may include one or more support segments that allow the ladder to be supported relative to the base plate of the wind turbine blade, particularly if a ladder support assembly platform is used. In this case, the ladder is suspended from the edge of the platform segment spaced apart from the manhole so that a gap remains between the ladder and the blade base plate. This gap can be bridged by one or more support structures, such as support feeds. The support structures can be attached to the ladder before or after the ladder is attached to the ladder support assembly, supporting the ladder relative to the base plate and facilitating access to the manhole.

[0029] Preferably, two ladders are attached to the ladder support assembly, with a first ladder positioned on the side of the base plate facing the inside of the hub and a second ladder positioned on the side of the base plate facing the inside of the blade, allowing a person to climb up from the foothold in the hub, through the manhole, and then use the second ladder to descend from the manhole into the inside of the blade on the opposite side of the base plate.

[0030] In a preferred embodiment, the second ladder is attached to the ladder support assembly by sliding it through a manhole toward the interior of the blade where the ladder support assembly is located and locking onto the ladder support assembly, particularly by hanging from the ladder support assembly. The second ladder can be slid, for example, over a platform segment of the ladder support assembly or another guide structure. The second ladder can be attached to the ladder support assembly by hanging from the ladder support assembly, and the ladder extends from the ladder support assembly toward the bottom of the interior of the blade it is entering.

[0031] Like the first ladder, the second ladder may also be hung over the edge of a platform segment spaced from the manhole, leaving a gap between the ladder and the blade base plate. This gap may be bridged by one or more support structures, such as support feeds. The support structures may be attached to the second ladder before or after the second ladder is attached to the ladder support assembly to support the second ladder relative to the base plate and facilitate access to the manhole.

[0032] The ladder support assembly for a wind turbine according to the present invention comprises at least one frame- or plate-shaped, in particular ring- or split-ring-shaped, support segment, which is mountable to a base plate of a wind turbine blade so as to at least partially surround a manhole in the base plate. The ladder support assembly comprises at least one mounting point for mounting a ladder to the ladder support assembly. The frame- or plate-shaped support segment is mounted to the base plate at or near the manhole and provides at least one mounting point for mounting the ladder to the ladder support assembly, in particular by hanging one side of the ladder on the ladder support assembly.

[0033] Preferably, the ladder support assembly includes two mounting portions, each located on an opposite side of the base plate when the ladder support assembly is installed, one of the mounting portions usable to mount a first ladder to allow climbing up from the footing in the hub towards the manhole, and the other of the mounting portions usable to mount a second ladder to allow climbing down from the manhole into the interior of the blade.

[0034] Preferably, the ladder support assembly includes at least one platform segment that is positionable relative to the manhole so that the platform segment extends through the manhole and / or is positioned on one side of the manhole to allow an operator to pass over the platform segment to exit the manhole. In particular, the platform segment may be mounted or mountable orthogonally or essentially orthogonally to a support segment attached to the rim of the manhole.

[0035] A wind turbine according to the present invention comprises at least one rudder support assembly according to the present invention. The wind turbine includes at least one blade having a base plate to which the rudder support assembly is attached. Preferably, all blades of the wind turbine are attached to a rudder support assembly. The wind turbine may include, in particular, three blades attached to the hub of the wind turbine. The rudder support assembly can be stored inside the wind turbine, for example, in the hub or in the nacelle adjacent to the hub. In addition to the rudder support assembly, one or more rudder(s), which can be attached to the rudder support assembly, can also be stored in the wind turbine.

[0036] The invention further relates to a wind turbine blade comprising a hollow blade body having a blade root and a base plate arranged at the root end of the blade, the blade including a manhole through which the interior of the blade is accessible, the base plate being provided with attachment means arranged at or near the manhole and configured to attach at least one ladder directly or indirectly to the base plate.

[0037] According to one embodiment, the base plate has no more than one manhole. This results in an optimal configuration of the base plate for structural loads. The blade contains only one manhole, and no other openings of a similar size allow a person to pass through. The base plate's primary purpose is to increase the blade's stiffness at the root end. This function is weakened if multiple manholes are provided to allow access to the interior at various locations. A base plate having multiple manholes must therefore have a comparable weight to be sufficiently stiff to perform its stiffening function. Because the blade of the present invention contains only one manhole, the base plate is highly stiff and does not require additional stiffening measures. Furthermore, the base plate is provided with attachment means located at or adjacent to the single manhole and configured to attach at least one ladder directly or indirectly to the base plate. The attachment means allows for the attachment of a ladder, which can be used by maintenance personnel to reach the manhole if it is located too far from the footing. If the manhole is close enough to the scaffolding, maintenance personnel can access the manhole directly from the scaffolding. On the other hand, if the manhole is rotated to a position that is not directly reachable from the scaffolding, personnel can easily attach a ladder to the attachment means and use this ladder to climb up to the manhole. The attachment means can also be configured to attach the ladder directly to the attachment means without using any other fixing or mounting equipment or tools. In this case, the attachment means already includes, for example, a hook-like attachment interface to which the ladder can be directly attached. Alternatively, the attachment means can be configured to indirectly fix the ladder using some additional mounting or fixing equipment or tools, which are attached to the attachment means, if necessary, and which ultimately attach the ladder. The attachment means can also be located directly on the manhole, which means that it is located as close to the manhole as possible.Alternatively, the attachment means may be located some distance from the manhole, provided that the manhole can be easily reached by personnel using the attached ladder.

[0038] The blade according to the invention is thus improved in terms of its rigidity, its respective set-up and its easy accessibility through one manhole, even if it is located away from the footing.

[0039] The mounting means is preferably configured to mount, directly or indirectly, a first ladder on a first side of the base plate facing away from the interior of the blade and a second ladder on a second side of the base plate facing the interior of the blade, thereby allowing the first ladder to be located, directly or indirectly, on the outside of the base plate to enable a worker standing on the platform to climb up to the manhole, and the second ladder to be located on the inside of the base plate to enable a worker to descend after passing through the manhole. The base for mounting both ladders is a common mounting means.

[0040] The attachment means may be permanently arranged on the base plate, meaning that they are permanently and rigidly attached to the base plate, for example by welding. Alternatively, the attachment means may be removably arranged on the base plate. The attachment means may be fixed, for example by screws or clamps, when the blades are assembled when the turbine is built or after the blades have been attached to the hub, in which case they can always be removed if required.

[0041] As mentioned above, the base plate contains only one manhole. The manhole is preferably circular or oval. This geometric shape can be easily cut from a regular metal base plate and does not significantly affect stability. The manhole should not be too large, allowing a person to easily pass through.

[0042] The attachment means can be considered the central item of the blade. It preferably consists of or comprises at least one frame- or plate-shaped support segment adapted to at least partially surround the manhole. Such a frame- or plate-shaped support segment provides a sufficiently stable attachment interface for attaching either a ladder or additional attachment equipment. This is particularly true when the attachment means is removably arranged on the base plate, for example, the frame- or plate-like design makes it possible to provide sufficient fixing elements for secure attachment to the base plate, preferably fixing elements in the form of clamps or the like fixed to the base plate edge extending around the manhole.

[0043] Preferably, the geometric shape of each support element of the mounting means is adapted in some way to the shape of the manhole. If the manhole is preferably circular or elliptical, the support elements are preferably U-shaped, circular, elliptical or polygonal. These geometric shapes allow the support elements to enclose the manhole to some extent. However, even if the manhole is, for example, rectangular, a U-shaped or polygonal support element can at least partially enclose the manhole.

[0044] According to another aspect of the invention, the mounting means may include two or more separate mounting positions assigned to different positions on the support element. As described above, the blade can be positioned in different rotational positions depending on which area of ​​the blade's interior requires maintenance. Thus, the manhole can be positioned closer to the footing or further away from the footing. If the support element is provided with only one predetermined mounting position for the ladder, the blade can be positioned in a first position closer to the footing and in a second position, rotated, for example, 180° relative to the first position, with the manhole higher above the footing. In contrast, if the support element is provided with two or more predetermined mounting position interfaces, the blade can also be rotated to predetermined intermediate positions that allow the ladder to be easily secured to the support element. This provides more flexibility in terms of possible maintenance positions, allowing different blade areas to be positioned well for subsequent maintenance. Each mounting position or mounting interface is realized by a fastening means or element configured to directly receive the ladder or to receive a separate mounting device for securing the ladder.

[0045] Preferably, each fixing means or element defining the mounting position is assigned to a separate circumferential position, which is particularly preferred when the support element has a closed configuration, such as a circular, elliptical, or polygonal configuration. In particular, in polygonal configurations, such as rectangular or hexagonal or octagonal configurations, which include a certain number of linear support element members forming a geometric shape, it is easily possible to provide each support element member with a mounting element or interface, so that the blades can be positioned in four different positions in the case of a rectangular support element, six positions in the case of a hexagonal configuration, and eight positions in the case of an octagonal configuration. Other polygonal configurations are also possible.

[0046] Finally, the base plate may be a single plate provided with the manhole and the mounting means. Alternatively, the base plate may include a first plate having a first manhole opening and a second plate arranged parallel to the first plate having a second manhole opening, the manhole openings being at the same height as each other to form a manhole. This base plate has a double-plate structure with two parallel plates arranged parallel and adjacent to each other. Both plates contain manhole openings, and both manhole openings are at the same height to form a single manhole. In this case, the mounting means may be attached only to the outer first plate, and additional mounting devices may be fixed, if necessary, to allow for the placement of at least a second inner ladder or both ladders.

[0047] All details and advantages described in relation to the method according to the invention apply equally to the ladder support assembly according to the invention and to the wind turbine, and therefore details and advantages described in relation to the ladder support assembly according to the invention also apply equally to the method according to the invention and to the wind turbine according to the invention and vice versa. [Brief explanation of the drawings]

[0048] Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings, which are merely principle sketches designed for illustrative purposes and are not intended to limit the invention. [Figure 1] 1 illustrates an embodiment of a wind turbine according to the present invention. [Figure 2] A wind turbine rotor with the incoming blade in the first position. [Figure 3] A wind turbine rotor with the incoming blade in the second position. [Figure 4] A detailed view of the base plate of an incoming wind turbine blade. [Figure 5]FIG. 10 is a detailed view of a manhole in a base plate with attached support segments of an embodiment of a ladder support assembly according to the present invention. [Figure 6] Manhole with ladder support assembly installed. [Figure 7] FIG. 10 is a cross-sectional view showing the installed rudder support assembly with the incoming blade in a second position. [Figure 8] A second rudder attached to the rudder support assembly inside the incoming blade. [Figure 9] 1 is a partial view of a wind turbine blade facing the blade root and provided with attachment means including multiple attachment locations for a rudder; [Figure 10] 1 is a cross-sectional view of a blade including a base plate having first and second plates and mounting means for mounting first and second rudders; DETAILED DESCRIPTION OF THE INVENTION

[0049] An embodiment of a wind turbine 1 is shown in Figure 1. The wind turbine 1 includes a tower 2, which supports a nacelle 3 of the wind turbine 1. A rotor 4 is attached to the front of the nacelle 3 and includes a hub 5 and a number of rotor blades 6. During operation of the wind turbine 1, the rotor 4 rotates and drives a generator (not shown) of the wind turbine 1 to produce primarily electrical energy.

[0050] 2 shows the rotor 4 in detail. The rotor 4 includes three rotor blades 6. The rotor blades 6 are attached to the hub 5 at their root ends 8, opposite their tips 9. The interiors 10 of the blades 6 are at least partially hollow and are each surrounded by a shell 11 of the blade 6. The blades 6 include a base plate 12 at each of their root ends 8.

[0051] In order to perform a maintenance routine or repair procedure inside 10 of one of the wind turbine blades 6, it may be necessary for a worker to access the interior 10 of the wind turbine blade 13 to enter. However, particularly if the rotor blade 6 has a large diameter at its root end, not all areas of the inner surface of the shell 11 are reachable by a worker standing inside the blade. In particular, since the wind turbine blade 6 may have a diameter of 2 m to 15 m, particularly a diameter of 3 m to 8 m, at the root end 8, a worker standing below cannot reach elements or sections of the shell 11 located at the top of the blade 13.

[0052] To facilitate understanding of the orientation of the blade 13 to be repaired, an arrow 7 is shown in Figure 2. In the figure, the incoming blade 13 is positioned in a first position. In this first position, the arrow 7 points from the underside of the blade 13 to the top. The blade in the first position is oriented at an angle α = 105°, measured counterclockwise when looking from the front of the rotor 4, or clockwise when standing inside the nacelle and looking towards the hub, relative to the vertical direction indicated by the dashed line 15.

[0053] 3 shows the rotor 4 after rotation, with the incoming rotor blades 13 now in a second position, where the blades are oriented at an angle α=270°. The relative direction of arrow 7 to blades 13 has not been changed to illustrate the effect of the rotation of the orientation of blades 13.

[0054] As can be seen from arrow 7, the orientation of blade 13 and sections of its shell 11 changes from the first position to the second position, so that areas or components of blade 13 that were at the top of blade 13 in the first position are now at the bottom, and vice versa. Specifically, when servicing large blades with diameters of 3 m or more, rotating the blade during a maintenance procedure allows workers to reach all relevant components or sections of shell 11 from inside blade 10.

[0055] 4 shows a detail of the base plate 12 of the wind turbine blade 6. To allow access to the interior 10 of the blade 6 from the hub 5, the base plate 12 is provided with a manhole 14. To access the interior 10 of the blade 13, workers must pass through the manhole 14, which is formed as an opening in the base plate 12.

[0056] The illustrated manhole 14 is shown as being circular, with a diameter that allows a worker to fit through the manhole 14. The manhole 14 may have a diameter of, for example, 50 cm to 1 m. Other shapes are also possible for the manhole 14, such as a rectangular or square manhole 14 with sides measuring 40 cm to 1 m.

[0057] The manhole 14 is offset from the center 16 of the base plate 12 so that the manhole 14 changes position when the blade 13 rotates to the second position as shown in Figure 3. The position of the manhole 14 in the second blade position is indicated diagrammatically by the dashed line 17.

[0058] In the first blade position, an operator can access the manhole 14 from a foothold 18 installed inside the hub 5. For example, the distance between the top of the manhole 14 and the top surface of the foothold 18 is 1.5 m or less.

[0059] In contrast, in the second position, the distance between the manhole 14 and the footing 18 is greater than in the first position. The distance from the footing 18 to the bottom of the manhole 14 can be greater than 1.5 m, for example, and in particular can be greater than 2 m or 2.5 m.

[0060] The footing 18 is stationary and does not change position when the rotor 4 of the wind turbine blade 1 rotates or when the blade 13 moves from a first position to a second position. For example, the footing 18 may be the top surface of a platform that is fixed to the nacelle 3 or to another structural element of the nacelle 3.

[0061] For example, in a repair procedure requiring access to four sensors equidistantly spaced around the inner circumference of a wind turbine blade 6, access to the blade 13 in both the first and second positions is required to access all of the sensors. Specifically, the sensors may be located at the 3 o'clock, 6 o'clock, 9 o'clock, and 12 o'clock positions around the inner circumference of the blade 13 in the first blade position. For particularly large blades, the top sensor at the 12 o'clock position may be inaccessible when the blade is oriented in the first position. However, this sensor will be at the 6 o'clock position when the blade is rotated to the second position, and therefore will be located lower inside the hollow blade 6 and easily accessible to the operator.

[0062] In one embodiment of a method for accessing the interior 10 of a hollow blade 6 of a wind turbine 1, the entering blade 13 is first positioned in a first position, as illustrated in Figure 2. In the first position, a manhole 14 in the base plate 12 is accessible to workers from a foothold 18, as can be seen in Figure 4. To allow access to the blade 13 in the second position, a ladder support assembly 19 is attached to the base plate 12 at or near the manhole 14 when the entering rotating blade 13 is positioned in the first position.

[0063] 5 shows the manhole 14 in the base plate 12 in detail with the blade 13 in the first blade position. A ladder support assembly 19 is attached to the edge of the manhole 14. The ladder support assembly 19 includes at least one support segment 20 attached to the base plate 12 near the manhole 14. In the illustrated embodiment, the ladder support assembly 19 includes two ring-shaped plates 21 and 22 that are attached to the base plate 12 around the perimeter of the manhole 14. The support segment 20 includes a flat portion 23 that is positioned on an upper edge 24 of the manhole 14 when the manhole 14 is in the first position.

[0064] 6, the other components of the ladder support assembly 19 can be assembled when the incoming rotating blade 13 is in the first position. The ladder support assembly 19 includes a platform segment 25 that is positioned on the flat portion 23 of the support segment 20. The ladder support assembly 19 also includes two handrails 26, 27 that are attached to the platform segment 25 and used to support the platform segment 25 relative to the support segment 20 and the base plate 12. The handrails 26, 27 can be attached to the platform segment 25 and / or to the support segment 20 by, for example, a plurality of bolt connections 28.

[0065] The platform segment 25 is attached to the flat part 23 of the support segment and thus to the upper edge of the manhole 14 in a first position, as the blade 13 is rotated to a second position before entering the manhole 14. The platform segment 25 therefore changes its position, in particular so that the platform segment 25 is located at the lower edge of the manhole 14 after the blade has rotated to the second position.

[0066] After attaching the rudder support assembly 19 to the manhole 14 or to the base plate 12, the blades 13 rotate to a second position. From a perspective looking toward the center of the hub 5 from inside the nacelle 3, the incoming rotor blades 13 may rotate, for example, from the right side to the left side or vice versa. The rotation of the blades 13 also causes the base plate 12 to rotate (revolve) about the central axis of the rotor 4, and the base plate 12 is positioned in a second position that is at least essentially upside down relative to the first position.

[0067] 7 shows a cutaway view of the base plate 12 with the incoming blade 13 rotated to a second position. The rotor blade 13 is on the left side of the base plate 12 and the hub is on the right side.

[0068] In this second position, the distance between the manhole 14 and the stationary footing 18 is greater than in the first position. The platform segment 25 includes a mounting portion 29 for attaching the ladder 30 to the ladder support assembly 19. In this embodiment, for example, the top rung 31 of the ladder 30 is attached to the mounting portion 29, which includes two hooks 32 for suspending the ladder 30 from the ladder support assembly 19. Note that the handrails 26 and 27 have been omitted from Figure 7 for clarity. The ladder 30, attached to the ladder support assembly 19 at its hub end, is supported on the base plate 12 by a support portion 33.

[0069] A rudder 34 is also mounted on the rudder support assembly 19 so as to be able to enter the interior of the hollow blade located on the left hand side in Figure 7. This other rudder 34 is attached to another mounting point 35 of the rudder support assembly 19. This mounting point 35 may, for example, comprise one or more hooks 36 onto which the rudder 34 can be hung.

[0070] To position the alternative ladder 34 on the blade side of the base plate 12, the alternative ladder 34 can be slid into the ladder support assembly 19, for example, into the platform segment 25, through the manhole 14. Insertion of the ladder 34 is shown diagrammatically in dashed lines in Figure 7. The alternative ladder 34 can also include supports 33 to support the ladder against the blade side of the base plate 12. The supports can specifically be attached before the alternative ladder 34 is attached to the ladder support assembly 19.

[0071] FIG. 8 shows a view of the blade side of base plate 12. Another ladder 34 is attached to ladder support assembly 19 located below manhole 14. Workers who need to enter the hollow interior of blade 6 can walk or crawl through manhole 14 on platform segment 25. The ladder is hung from ladder support assembly 19, for example, by hooking top rung 37 of ladder 34 onto hook 36 of mounting portion 35. With both ladders aligned vertically toward the lower edge of manhole 14 in the second blade position, a worker can climb from foot platform 18 onto platform segment 25 of ladder support assembly 19 and then climb down into the blade.

[0072] After performing the necessary maintenance routines and / or repair procedures, the rudders 33, 34 and rudder support assembly 19 can be removed by performing the steps described above in reverse order. The wind turbine 1 includes the rudder support assembly 19 and / or the rudders 33, 34, which can be stored, for example, inside the hub 4 and / or inside the nacelle 3.

[0073] In an alternative embodiment of the method for gaining access to the interior of one of the blades 6, the blade 13 to be entered can be placed in a second position with an angle α=0° pointing vertically upwards. In this case, the blade can be accessed by a ladder hung on the ladder support assembly 19. The ladder is then positioned at least essentially perpendicular to the base plate 12, and an operator can climb it and enter the blade through the manhole 14.

[0074] In this case, the support segment 20 of the ladder support assembly 19 attached to the edge of the manhole 14 may include a mounting portion 29 with two hooks, for example as described above, oriented to allow the ladder to be hung on the ladder support assembly 19 when the blade 13 is in the second vertical position. In this embodiment, the platform segment 25 and / or the handrails 26, 27, respectively, are not attached to the support segment 20 and may be omitted.

[0075] Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the disclosed embodiments, and those skilled in the art can derive other modifications from these embodiments without departing from the scope of the present invention.

[0076] FIG. 9 illustrates the main parts of a wind turbine blade 6, which typically includes an outer shell 11 and a root section with a root end 8 to which a base plate 12 is attached. The view shows the root section. The base plate 12, like the previous embodiment, has only one manhole 14, which is eccentrically positioned relative to the center 16. The base plate 12 is provided with a mounting means 38, which includes a frame-like support segment 20 and, optionally, several additional mounting fixtures or elements. The support segment 20 of the mounting means 38 is polygonal, here rectangular, in this example. The support segment 20 of the mounting means 38 (and any additional fixing fixtures or elements) is permanently attached to the base plate. Permanent in this case means that the support segment of the mounting means (and any optional fixing fixtures) is already attached to the base plate at the blade manufacturing site and remains on the base plate when the blade is attached to its respective hub, and can remain there throughout the life of the blade once the wind turbine is finally assembled and operational. The attachment can be permanent or removable. This can be achieved, for example, by welding the support segments 20 to a metal base plate or by using fastening means such as screws or bolts and nuts or clamping elements.

[0077] The support segment 20 is positioned adjacent to the manhole 14 and completely surrounds it like a frame. The rectangular support segment 20 comprises four longitudinal support element members 39a, 39b, 39c, and 39d. Two of these members, namely members 39b and 39c, are provided with fastening means 40b and 40c. The fastening means 40b and 40c can be various fastening elements that provide either a fastening interface for attaching the ladder directly to the support segment 20 or some additional fastening device that ultimately attaches the ladder so that the ladder is indirectly fixed to the support segment 20. Therefore, the fastening means are located at different circumferential positions relative to the center of the manhole 14 or the frame-like shape of the support segment 20.

[0078] When the blade is in the rotated position with the manhole 14 near the footing 18 as shown, workers have direct access to the manhole 14 from the footing 18. This allows for inspection and work on the lower blade body area below in this rotated position. If maintenance is required on the surface area further to the right of the blade, the blade is rotated approximately 90° clockwise, bringing the manhole 14, along with the support segment 20, into the upper left position shown in dashed lines. After the 90° rotation, the support element 39b, along with its fastening means 40b, is now in its lower position, allowing a ladder to be attached to allow workers to reach the manhole 14 elevated from the footing 18. If maintenance is required on another interior area, the blade is rotated another 90° clockwise so that the manhole 14 is in the upper right position. In this position, the support element 39c, along with its fastening means 40c, is at its lowest, allowing a ladder to be attached there. This allows maintenance to be performed on the area opposite the area below in the initial rotated position. Finally, by rotating the blade clockwise another 90°, another interior area can be brought into position for maintenance. The manhole 14 is again in a lowered position directly accessible from the footing 18, without the need for a ladder. In this manner, each position can be reached directly. In this embodiment, each interior area can be brought into a good position for maintenance work, and the manhole is always easily accessible to workers, either directly from the footing or via an attached ladder. The ladder can be firmly and safely attached to the support segment at the designated rotational position where the ladder is needed to reach the manhole 14.

[0079] The rectangular design shown is merely exemplary. The support segments 20 with one or more fastening means may have various shapes, for example, circular or polygonal, as well as rectangular. A U-shape is also possible, in which case they partially surround the manhole 14 and may each be equipped with a fastening means.

[0080] FIG. 10 shows a cutaway view of the blade 6 at the root end 8, revealing the base plate 12, a sort of sandwich structure made up of two separate plates. The base plate 12 consists of a first plate 41 near the open end of the root end 8 and a second plate 42 facing the interior of the hollow blade body. The plates 41, 42 are similarly sized and are arranged parallel and close to each other. The first plate 41 has a first manhole opening 43, and the second plate 42 has a second manhole opening 44. Both manhole openings 43, 44 are at the same height and form a common manhole 14.

[0081] The support segment 20 is provided with a mounting means 38, which is permanently attached to a first plate 41 facing the open end of the root end 8, to which the first ladder 30 is attached. The mounting means comprises a hook 32, which may form the fastening means described in connection with FIG. 9. As an additional, and permanent, fastening device, a mounting part 35 with another hook 36 is attached to the support segment 20. The mounting part 35 extends through the manhole, i.e., both manhole openings, with the hook 36 positioned inside the second plate 42. The second ladder 34 is attached to the hook 36. A worker can use the first ladder 30 to climb up to the manhole 14 and the second ladder 34 to descend to the maintenance area, or vice versa.

Claims

1. A wind turbine blade (6, 13) comprising a hollow blade body having a blade root and a base plate (12) disposed at a root end (8) of the blade (6), The base plate (12) includes a manhole (14) that allows access to the interior of the blade (6); The base plate (12) is provided with attachment means (38), which are arranged in the manhole (14) or in the vicinity of the manhole (14) and are configured to attach at least one ladder (30, 34) directly or indirectly to the base plate (12).

2. 2. The wind turbine blade (6, 13) of claim 1, wherein the base plate (12) includes one manhole (14) and no more than one manhole (14).

3. The attachment means (38) a first rudder (30) attached directly or indirectly to a first side of said base plate (12) facing away from the interior of said blade (6); 2. The wind turbine blade (6, 13) according to claim 1, configured to attach a second ladder (34) directly or indirectly to a second side of the base plate (12) facing towards the interior of the blade (6).

4. 2. The wind turbine blade (6, 13) according to claim 1, wherein the attachment means (38) is permanently arranged on the base plate (12) or the attachment means (38) is removably arranged on the base plate (12).

5. The wind turbine blade (6, 13) according to claim 1, wherein the manhole (14) is circular or oval.

6. 2. The wind turbine blade (6, 13) according to claim 1, wherein the mounting means (38) is or comprises at least one frame- or plate-shaped support segment (20) at least partially surrounding the manhole (14).

7. 7. The wind turbine blade (6, 13) according to claim 6, wherein the shape of the support segment (20) is U-shaped, circular, elliptical or polygonal.

8. The wind turbine blade (6, 13) according to claim 6, wherein the attachment means (38) comprises two or more different attachment locations allocated to different positions of the support segment (20).

9. The wind turbine blade (6, 13) according to claim 8, wherein the different mounting positions are assigned to different circumferential positions.

10. The base plate (12) is a single plate, or 2. The wind turbine blade (6, 13) of claim 1, wherein the base plate (12) comprises a first plate (41) having a first manhole opening (43) and a second plate (42) arranged parallel to the first plate (41) and having a second manhole opening (44), the first and second manhole openings (43, 44) being at the same height as each other to form the manhole (14).

11. 1. A ladder support assembly for a wind turbine, comprising: The ladder support assembly (19) includes at least one frame-shaped or plate-shaped support segment (20), which is attached to a base plate (12) of the wind turbine blade (6, 13) and at least partially surrounds a manhole (14) in the base plate (12); The rudder support assembly (19) includes at least one mounting portion (29, 35) for mounting a rudder (30, 34) to the rudder support assembly (19); and / or 2. A rudder support assembly (19) configured to be attached to a wind turbine blade (6, 13) according to claim 1.

12. The ladder support assembly (19) includes two mounting portions (29, 35); 12. A ladder support assembly according to claim 11, wherein, in an installed state of the ladder support assembly (19), each of the mounting portions (29, 35) is located on an opposite side of the base plate (12).

13. The ladder support assembly (19) includes at least one platform segment (25); 13. A ladder support assembly according to claim 11 or 12, wherein the ladder support assembly (19) is positionable in the manhole (14) such that the platform segment (25) extends through the manhole (14) and / or is positioned on one side of the manhole (14), allowing an operator to pass over the platform segment (25) to exit the manhole (14).

14. A wind turbine comprising at least one wind turbine blade (6, 13) according to claim 1 and / or at least one ladder support assembly (19) according to claim 11.

15. A method for allowing passage into the interior of a hollow blade (6, 13) of a wind turbine (1), comprising: the blades (6, 13) are mounted on a rotatable hub (5) of the wind turbine (1), the interiors (10) of the blades (6) being accessible from the hub (5) through manholes (14) in a base plate (12) at the root ends (8) of the blades (6, 13); The method comprises: placing the blade (6, 13) in a first position; In the first position, the manhole (14) is accessible to an operator from a footrest (18) inside the hub (5), the footrest (18) being stationary when the hub (5) rotates; attaching a ladder support assembly (19) to said base plate (12) at or near at least one edge of said manhole (14); placing the blades (6, 13) in a second position by rotating the hub (5); In the second position, the distance between the manhole (14) and the footing (18) is greater than in the first position, Attaching at least one rudder (30, 34) to the rudder support assembly (19) for entry into the interior of the blade (6, 13).

16. the blades (6, 13) are oriented at an angle of 90° to 120° relative to a vertically upward position of the blades (6, 13) in the first position; and / or 16. The method of claim 15, wherein the blades (6, 13) are oriented vertically upwards or at an angle of 255° to 285° in the second position.

17. 16. The method of claim 15, wherein the ladder support assembly (19) is mounted at least at or near an upper edge of the manhole (14) when the blade (6, 13) is in the first position.

18. 16. The method of claim 15, wherein the ladder support assembly (19) includes at least one frame- or plate-shaped support segment (20), the support segment (20) attached to the base plate (12) so as to at least partially surround the manhole (14).

19. The ladder support assembly (19) includes at least one platform segment (25); 16. The method of claim 15, wherein the ladder support assembly (19) is positioned in the manhole (14) such that the platform segment (25) extends through the manhole (14) and / or such that the platform segment (25) is positioned below the manhole (14) when the blade (6, 13) is in the second position.

20. 16. The method of claim 15, wherein the at least one ladder (30, 34) is hung on the ladder support assembly (19).

21. Two ladders (30, 34) are attached to the ladder support assembly (19); a first ladder (30) of the two ladders (30, 34) is arranged on a side of the base plate (12) facing the inside of the hub (5); 16. The method according to claim 15, wherein the second rudder (34) of the two rudder (30, 34) is arranged on the side of the base plate (12) facing towards the inside of the blade (6, 13).

22. 22. The method of claim 21, wherein the second ladder (34) is attached to the ladder support assembly (19) by sliding it over the ladder support assembly (19) through the manhole (14) toward the interior of the blade (6, 13) and attaching it to the ladder support assembly (19).

Images