Securing system and subsequent method for exchanging wind turbine blades

Abstract

The blade (10) is lifted without the use of large cranes, using at least one lifting cable (11a) attached to the blade root (10") and controlled from inside the rotor (12) for raising and lowering. With the aid of a yoke secured to the blade tip (10"), the blade (10) is rotated and held correctly positioned both horizontally and vertically, absorbing loads and torsional moments. The yoke and the peripheral anchors (9) of the pull cables, which are incorporated on the yoke, allow the blade to rotate along a longitudinal axis and a transverse axis. The pull cables are located around the periphery of the yoke and are auxiliary cables (11b), guiding or retaining cables (11c) and safety cables (11d). All hoists, closure elements, and cables are controlled from the ground by a general remote control (18) that activates the other remote controls (18a, 18b, 18c, 18d). The method is valid when the blade is on the ground in a horizontal position and when the blade is secured to the rotor (12) of the wind turbine.

Description

[0001] FIXING SYSTEM AND METHOD USED FOR THE EXCHANGE OF

[0002] WIND TURBINE BLADES

[0003] Field of invention

[0004] The present invention describes the method for lowering the blade of a wind turbine without the use of an external crane and the system for fixing the blade tip, called a tile.

[0005] Background

[0006] The prior art protects various support solutions for wind turbine blades during storage and transport. However, the object of the present invention is more specific. The fixing tool is used specifically for the assembly or disassembly of blades, and its main function is to stabilize the blade by securing it from the tip during these operations. From this perspective, the most relevant patents are the following:

[0007] US patent 2016040649A1 can be considered to use the most basic tile or cover for securing the blade. It is made of fabric and is applied over the blade tip, holding it firmly in place during lifting and lowering. Using the cable and hook on the tile, in combination with the auxiliary crane, the blade can be raised vertically.

[0008] Patent EP2412659A1 presents a tool for raising and lowering a shovel. The tile achieves its closing force by utilizing the shovel's own weight. It has four diamond-shaped hinged points to narrow the tile and hold the shovel by its tip.

[0009] Patent WO2021022361 A1 presents a tile having a single spring hinge at one end and a pulley cable assembly at the opposite end. Pulling the cable assembly adjusts the tile to the blade. With five or six external cables, control over the blade's vertical position is achieved.

[0010] US patent 10113530B2 describes a flexible cover, or rather, a flexible sleeve. It is secured with a strap that covers the tip of the blade and with the tension of the cables that control it, which are responsible for adjusting the sleeve. Another feature of this sleeve is that it can move laterally along the blade thanks to the lifting cable. Curved supports are used beneath the sleeve to protect the leading and trailing edges of the blade.

[0011] There is no known in the state of the art a rigid tile with the characteristics presented in this invention, to allow handling the shovel from the ground to its assembly, rotating the shovel according to different axes and fixing the shovel without damaging it.

[0012] The blades are handled with a large external crane of the same height as the wind turbine itself, since the quickest and easiest way to install the blade is to lift it horizontally from the ground and assemble it on the rotor. In these cases, the element that supports the blade horizontally is much more complex and larger than the tile that is the subject of this invention. In the case at hand, the blade is lifted without the use of large cranes, with at least one cable attached to the blade root, which is controlled from inside the rotor to raise and lower it. With the help of the tile, the blade is rotated and held correctly positioned both horizontally and vertically. The tile and the pull cable anchors it incorporates allow the blade to be rotated around both a longitudinal and a transverse axis.

[0013] It is an object of the invention that the pull cable anchors are arranged on the periphery of the blade and can be operated remotely. The pull cables consist of auxiliary cables, guide or stay cables, and safety cables. In addition to these cables, a hoist cable extends between the blade root and the rotor.

[0014] Another object of the invention is that the tile, preferably metallic, can be fully opened, has remote-controlled opening / closing, and a pressure control system in the blade housings. The pressure exerted on the blade housings cannot exceed 0.5 MPa, otherwise it will be damaged. The full opening facilitates installation with the blade resting on the ground without lifting it from its transport supports, providing greater versatility. The remote partial opening allows the tile to be installed / removed with the blade mounted in the hub, using the safety cables.

[0015] Another object of the invention is that the bearings and pads that prevent the blade from slipping are: bearings on the leading edge to facilitate the guidance of the blade, pads made of soft foams in contact with the shells and a hard rubber in contact with the cap.

[0016] The tile hangs from the spade root by two safety cables: one at the back and one at the front. If the tile's hydraulic locking system fails, the cable prevents the tile from falling. Initially, the spade root is bolted to the hub. When the root is released, the load is transferred from the hub to the spade, and the safety cables also transfer the load, as they connect the spade root to the tile. The safety cables also help lift the tile from the ground and, with the help of the stay cables, guide it into the spade without the need for a crane and using remote control.

[0017] From everything described above, the following advantages in the essential functions of the tile emerge:

[0018] It is capable of withstanding vertical loads and torque when the blade is in a horizontal position on or near the ground (Fig. 2),

[0019] - is capable of withstanding the horizontal load and torque when the blade is hanging in a vertical position (Fig. 5.),

[0020] - It is able to secure its position on the blade by means of pressure and secure cables,

[0021] - It is capable of being installed on the shovel without the need for cranes using secure cables.

[0022] Brief description of the drawings

[0023] The following section briefly describes a series of drawings that help to better understand the invention and that expressly relate to an embodiment of said invention, presented as a non-limiting example. Figures 1a and 1b show a tile as a fastening system, and Figures 1c and 1d show a second practical embodiment with a different shovel.

[0024] Figures 2, 3, 4, 5, 6 and 7 show the different phases of lifting, rotating and subsequent fixing of the shovel with the help of the tile.

[0025] Figure 8 shows the final movement for the definitive fixing of the blade to the rotor.

[0026] Figure 9 shows the set of remote control systems used during the assembly of the blade.

[0027] Detailed description

[0028] As shown in Figures 1a and 1b, the fixing system, called the tile, consists of a rectangular frame whose longer sides (1) include the shock-absorbing elements. These shock-absorbing elements are soft foam pads (2) distributed across the blade shells (10) and hard rubber pads (3) in contact with the blade cap or beam (10e). The short sides (4) of the tile house the bearings (5) and hinges (6) on one side and the pressure-controlled opening / closing device (7) on the other. The bearings (5) ensure smooth tile movement and prevent damage to the blade when one tile is inserted into the other. The opening / closing device is used to position the tile on the blade, whether it is on the ground or attached to the rotor. The remote pressure control ensures that the blade is not damaged during tile closure by regulating the pressure applied.

[0029] Inside the tile, the blade (10) is supported, represented by its section. It has a leading edge (10a), a trailing edge (10b), a suction side (10c), a pressure side (10d), and its cap or beam (10e) in the middle of the blade's profile (10).

[0030] Figures 1c and 1d show a second embodiment of the tile for a different blade design, resulting in different loads and torque. The new tile remains rectangular, with elongated sides (1) incorporating damping elements such as soft foams (2) distributed across the shells (10c and 10d) and hard rubbers (3) in contact with the cap (10e). The short sides (4) include the bearings (5) and hinges (6), as well as the pressure-controlled opening / closing system (7).

[0031] On both tiles, extending around their periphery, all the anchors (9) are arranged. There, the auxiliary cables (11b), the guide or stay cables (11c) and the safety cables (11d) are anchored, as shown in figure 2. The blade lifting system consists of a lifting cable (11a), which can be a cable or a bundle of cables, remotely controlled from inside the rotor (12) and attached to the root of the blade (10').

[0032] There are two singular moments shown between figure 2 and figure 8: Moment 1.- When the shovel is horizontal, being raised from the ground.

[0033] The blade lifting system from inside the rotor is not capable of stopping the torque at the root when the blade is horizontal. In addition to preventing the blade from falling to the ground, it is necessary to prevent the blade from rotating on its axis. To prevent this rotation, two cases are presented:

[0034] Case A, tile of the first realization figures 1a and 1b, the blade must be allowed to rotate and remain in equilibrium, ensuring that the CG is below the point of release (as low as possible). In this first case, the trailing edge (10a) of the blade is downwards and the tile cannot have a torsional moment.

[0035] Case B, tile of the second embodiment, figures 1c and 1d. The blade is carried horizontally, with the leading edge (10a) and trailing edge (10b) in the same plane. The tile is supported at four points, and the torsional moment is absorbed. The damping elements (2 and 3) help to counteract the torsional moment without damaging the blade.

[0036] Moment 2.- When the blade is vertically hanging from the wind turbine.

[0037] The tile must prevent horizontal wobble due to wind impacting the blade (10). This is achieved using at least three stays (11c) arranged at 120°. However, torsional moment remains, as the blade (10) is suspended from a hoist cable (11a) (or a cable bundle), allowing it to rotate about its axis. Adding another stay to the tile prevents the blade from rotating and wobbling. Two stays (11a) are located at the leading edge (10a) and two at the trailing edge (10b), with the stays at 90° to each other. The point where the two stays (11a) at the leading edge (10a) intersect must be as far apart as possible from the point where the two stays (11a) at the trailing edge (10b) intersect to maximize torsional leverage. For this purpose, extenders (8) are added to the tile to achieve more arm and retain the torsional force.The cables and the tile transmit this retention to the paddle (10) through the contact rubbers (3) with the cap (10e) and the foams (2) in contact with the shell (10c and 10d). This is case A in figures 1a and 1b.

[0038] For movement away from the blade when it is horizontal, at least one pull point (11b) (which can be two at the ends of the tile) is needed to prevent the blade from rotating around its axis. For movement perpendicular to the blade (10) when it is vertical, at least three pull points (11c) are needed. To also counteract rotation around the blade's axis, the number of stopes (11c) needs to be increased to four.

[0039] For torsion, two pulling points on a hook and two anchor points (9) are needed. Two cables are required so that one is tauter than the other when the blade is vertical. These are the auxiliary cables (11b) with the auxiliary crane (13).

[0040] The assembly method followed is as follows:

[0041] Figure 2 shows the beginning of the lifting process of the blade (10) positioned in the field. First, the blade root (10') is attached to the lifting cable (11a) controlled by a hoist located inside the rotor (12). The tile is opened and fixed to the tip of the blade (10"), which is in the resting position. The anchors (9) are secured with the auxiliary cables (11b) that run to the crane (13) and are remotely controlled from the crane itself. The blade (10) is in a horizontal position with the leading edge (10a), the trailing edge (10b), and the elongated sides (1) of the tile parallel to the ground (14).

[0042] In Figure 3, the blade (10) is rotated about its longitudinal axis so that its trailing edge (10b) faces downwards, towards the ground (14). The lifting process then begins by retrieving the hoist cable (11a) controlled from the pulleys inside the rotor (12). The rotation is achieved by pulling on the auxiliary cables (11b) attached to their corresponding anchor points (9) and controlled from the crane (13). In Figures 4 and 5, the blade (10) is gradually raised vertically until its tip (10") is clear of the ground (14). This is controlled at all times by the auxiliary cables (11b) of the small auxiliary crane (13) to prevent it from colliding with the tower (15) due to wind.

[0043] In Figure 6, the auxiliary cables (11b) are released by remote control, and the guide cables or stays (11c), controlled by their respective hoists (16) located on the ground (14), are tensioned. Safety cables (11d) extend from the tile to the root of the blade (10').

[0044] In Figure 7, the blade (10) is continued to be hoisted by means of the hoisting cable (11a) until the root of the blade (10') reaches next to the rotor (12), while the guide or restraint cables (11c) prevent damage to the blade (10) against the tower (15) by the effect of the wind.

[0045] In Figure 8, to complete the assembly of the blade root (10') in the rotor (12) avoiding tilt and coning of the blade (10), one of the guide cables or retainers (11c) is activated, and in turn the alignment and fitting system (17) inside the rotor (12) is activated, which rotates the blade enough to fit the bolts and complete the assembly.

[0046] Once the process is completed, the tile is opened with the remote opening system and lowered to the ground, guided by the secure cable (11 d) controlled from the base of the shovel (10').

[0047] Figure 9 shows the arrangement of the remote control systems mentioned above. The main remote control (18) is located on the ground (14) and operates the tile opening / closing / pressure control remote control (18b), the hoist remote control (18c) for the stays (11c), the safety cable remote control (18d) for the safety cables (11d), and the rotor remote control (18a), which is a dual control: one for the hoist cables (11a) and another for the alignment and engagement system (17) that prevents tilt and coning of the bucket. As shown in the figure, the safety cables (11d) help prevent the tile from falling when it is released from the bucket.

[0048] During the installation of the blade with the fixed blade on the wind turbine, the blade is hoisted by the safety cables (11d) from the blade root (10'). The stays (11c) help thread the blade onto the blade, and the foam inserts (2) prevent damage to the blade. Finally, the blade is closed remotely (18b). This method also allows for the lowering of the blade mounted on the wind turbine. The blade can also be installed using a crane, lifting it from the ground (14) to the tip of the blade (10").

Claims

CLAIMS 1- Wind turbine blade fixing system, of the type of a hinged rectangular tile that hugs the tip of the blade (10”) in order to give it stability during its lifting with at least one lifting cable (11a) disposed between the root of the blade (10') and the inside of the hub (12) characterized in that it has: - a frame, inside which are arranged damping elements (2 and 3) and sliding elements (5), - a frame on the outside of which there are peripheral anchors (9) where the pulling cables are fixed, which are: auxiliary cables (11b), the stays (11c) and the safety cables (11d), - The anchors (9) and the pull cables absorb the torsional moment generated in the blade by hanging from at least one lifting cable (11a) and allow the blade to rotate from the horizontal position to the vertical position and vice versa, while supporting the horizontal and vertical loads, all controlled by a main remote control (18). 2- Fixing system according to claim 1, characterized in that the frame has opening and closing elements, and the shock-absorbing elements (2 and 3) are arranged on the longer sides (1) of the frame and are soft foams (2) in contact with the shells (10c and 10d) and hard rubbers (3) in contact with the cap or beam (10e) of the blade and the sliding elements are bearings (5) that are arranged on the shorter sides (4) of the frame and are for the blade to move well and not be damaged when entering the fixing system. 3- Fixing system for wind turbine blade according to the previous claim, characterized in that with some vertical loads and with a certain torsional moment due to the blade (10) being hanging from a lifting cable (11a), two stays (11c) are fixed from the anchors (9) on the leading edge (10a) and at 90° another two stays (11c) are fixed on the trailing edge (10b) and the extenders (8) are added to the frame of the fixing piece to achieve more arm. 4- Fixing system according to claim 1, characterized in that the main remote control (18) is disposed on the floor (14) and commands the remote control (18b) of the fixing system / pressure control system, the remote control of the hoists (18c) of the stays (11c), the remote control (18d) of the safety cables (11d) and the remote control (18a) of the rotor (12): one for the hoists of the lifting cable (11a) and another for the alignment and inlet system (17). 5- Method for exchanging a wind turbine blade held by a hinged rectangular tile applied to the tip of the blade (10”) characterized in that, with the blade on the ground (14), horizontal, with the leading edge (10a) and the trailing edge (10b) parallel: - the tile opens and the shovel (10) is caught by its tip (10”), - a hoist cable (11a) extends from the root of the blade (10') to the hoist inside the rotor (12), - from the peripheral anchors (9) of the tile, the auxiliary cables (11b) extend to the auxiliary crane (13) and the safety cables (11d) between the shovel root (10') and the tile, - the blade is rotated and placed with the trailing edge (10b) downwards, the rotation is carried out by pulling the auxiliary cables (11b) fixed in their corresponding anchors (9) and controlled from the crane (13), - the blade (10) is raised from a horizontal to a vertical position, collecting the lifting cable (11a) and compensating for the vertical loads and the torsional moment with the auxiliary cables (11b), - the auxiliary cables (11b) are released and from the hoists (16) on the ground (14) the stays (11c) are extended to their respective anchors (9), - with the guide cables or retainers (11c) the blade (10) is guided to the rotor (12) and by pulling on at least one of the retainers (11c) tilt and coning are avoided, aided by the alignment and entry system (17), - The tile is opened when the blade (10) is fixed to the rotor (12) and the tile is lowered to the ground using the safety cables (11 d). If the blade (10) is initially fixed to the wind turbine, the tile is attached to the tip of the blade (10) with the help of a crane or the safety cables (11 d), and the lowering cable (11a), the stays (11c) and the auxiliary cables (11b) are used, performing the opening and closing of the clamp and anchors, remote control of cables and hoists from the ground (14) with the main control (18).

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