Alignment and insertion system for lowering blades without using crane

Abstract

A system for lowering blades without the use of a crane solves the misalignment and insertion problems due to the inclination and taper of the blades along the initial / final 200-400 mm as well as the space problem inside the hub. The system is characterized in that it moves the vertical load of the blade by 90 DEG, converts it into a horizontal load actuated by at least two hydraulic elements (14), and vertically aligns the center of gravity (CoG) of the blade with the center of the bearing by means of a cable (5) and pulleys (13, 21). Each of the systems is arranged inside the hub (1) in the bottom portion thereof and is fixedly connected to a fixed portion (19). The system comprises three main parts: a pulley (13), a hydraulic element (14) and an axis transformation element (15) secured by pins, one of which is fixed and the other is an adjustable pin (22). The cable (5) next to the end pulley (13) comprises a connector (7) in front of the point at which it passes through the inner pulley (24), which evenly distributes the load between the two cables (5).

Description

Technical Field

[0001] The proposed system fits into the reduced space inside the hub of a wind turbine and seeks to improve time and operating costs in assembly, replacement or repair of blades without the need for large cranes. Background Art

[0002] Document PCT / ES2021 / 070488 from the same applicant proposes an alignment and insertion system in which at least one rigger lowers the first 200-400 mm of the blade, rotating it to align the center of gravity (CoG) displaced by the taper and tilt of the blade. For some models of wind turbines, space and line-of-sight problems arise at the bottom of the hub interior. The rigger used in the alignment and insertion system cannot be installed because there is no hole in the upper part of the hub that has a line of sight with the hole for passing the cable (which is responsible for ensuring that the entire load suspension functions inside the hub).

[0003] Other wind turbine models have high taper and tilt angles, which cause the vertical projection of the blade's center of gravity at the bearing level to be displaced, becoming outside the bearing's own circumference. The new system allows the blade to rotate more easily, with the blade's center of gravity vertically aligned with the center of the bearing's circumference.

[0004] A requirement for operating the blade lowering system without using the crane presented in this patent is that all lifting elements used are fixed inside the hub and not outside the wind turbine (outside the hub or in the nacelle) or on the ground close to the tower foundation. The presented solution solves the problem of existing reduced space and center of gravity shift, also suitable between the hub and the blades, meeting the above prerequisites. Summary of the invention

[0005] One object of the invention is to provide a hydraulic system that rests directly on the inner ring of the bearing that houses the blade to be lowered, or on a possible element for blade extension that can be arranged between the bearing and the blade itself. For the attachment of this new alignment and insertion system, the necessary clearance between the hub and the beginning of the blade is minimized to the greatest extent possible.

[0006] Another object of the invention is to arrange the cylinders of the hydraulic system horizontally, as it allows for greater stroke capacity.The vertical position of the cylinders described above does not minimize the space required in the lower part of the hub.

[0007] Another object of the invention is that the anchoring of the hydraulic system is achieved by means of pins that are fixed as tightly as possible to the holes that house them, at least one of which is an adjustable pin.

[0008] With the new system, the center of gravity (CoG) is always controlled to mitigate the effects of pitch and taper. The CoG must be comfortably controlled and moved until it aligns with the clamping point, which is where the lifting / lowering system will attach to the blade.

[0009] Finally, another object of the invention is that the cylinders of the system are at least two, and preferably three: two front cylinders and one rear cylinder. The center of gravity is aligned with the two front systems, since in this case the third system will remain prestressed to ensure that no openings appear in the rear support area between the blade and the bearing.

[0010] From all that has been described above, the following advantage results: the alignment movement, which was previously performed manually by intervening in the chain to lift or lower the blade and align the center of gravity with the clamping point, is now done by operating a hydraulic system which allows maintaining the same stroke capacity in a much smaller space by redirecting the load by 90°. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Below a brief description will be given of a series of drawings which facilitate a better understanding of the invention and which relate expressly to an embodiment of said invention presented as a non-limiting example thereof.

[0012] FIG. 1 shows the prior art.

[0013] Figure 2 Sections of the hub bottom and restrictor plate are shown.

[0014] Figure 3 The layout of the new alignment and insertion system is shown.

[0015] Figure 4 Details of the cable connection to the blade root are presented.

[0016] Figure 5 The location of the center of gravity and its alignment are shown.

[0017] Figure 6 An insertion system and a lowering system are shown.

[0018] Figure 7a A system for hydraulic piston extension is presented.

[0019] Figure 7b A system is presented where the piston is retracted and the vanes are unhooked.

[0020] FIG8 shows a cross-sectional view of a portion of the new alignment and insertion system. DETAILED DESCRIPTION

[0021] As shown in FIG. 1 of the prior art described in patent PCT / ES2021 / 070488, the hub (1) is cut away and its internal structure is shown. In the upper part of the chassis (2), on a fixing ring at the junction with the upper blade and using auxiliary beams (3), the alignment and insertion system is anchored by at least one and preferably two hoists. Therefore, each of the two hoists (4) of the alignment and insertion system has a pair of cables (5) with a set of chains (6) and connectors (7). The greatest requirement is that the cables (5) must pass through the bearings and be anchored in the holes (8) of the T-bolts / blade root inserts (9). To achieve this, some pulleys (10) are needed to share the load, so that two cables (5) are used for each hoist (4).

[0022] The new alignment and insertion system object of this patent is used when the fixing and use of the hoisting machine (4) inside the hub (1) is not feasible.

[0023] Figure 2 It is shown how the connection between the hub and the blade incorporates a plate (11) which limits the line of sight of the hole (11') for passing the cable (5). In this detailed practical embodiment, the root of the blade (9) has its peripheral bolt holes (8) connected by one of its ends to an extension ring (11") which has an upper plate (11) and, as shown in the following figure, at its opposite end, it is attached to the bearing (12) of the blade.

[0024] like Figure 3 In the figure shown, the plate (11) has been removed in order to facilitate viewing of the different elements of the new system anchored in holes (11') present on the inner surface of the extension ring (11"). In other practical embodiments, the extension ring (11") is absent and the bearing (12) is in contact with the root of the blade (9).

[0025] On the other hand, the new blade alignment and insertion system consists of three main elements: a pulley (13) at the end, a hydraulic cylinder block (14) and an axis transformation element (15), which arranges the load of the blade at 90°. Two cables (5) extend from each of the three systems shown in the figure, pass through an extension ring (11) and are then screwed into an insert (8) at the root of the blade (9). Each cable (5) has a connecting element (16) at its end, which is formed by two parts threaded together. The truncated conical part with a thread inside is the upper part (17). And the lower part (18) consists of a threaded cylindrical area with a threaded convex protrusion. As Figure 4 As shown in , the connection is made using a threaded protrusion present in the cylindrical portion (18) and a threaded hole present in the frustoconical portion (17).

[0026] The points at which the pairs of cables (5) are arranged are each approximately 120° apart. They are in fact aligned and as close to the center of gravity as possible. In some practical embodiments, the vertical projection of the center of gravity on the bearing plane is outside the circle forming the root of the blade (9), such as Figure 5 The use of different cables (5) and the load required for each cable allow modifying the blade angle and thus the vertical projection of the center of gravity until it is aligned with the clamping point.

[0027] The axis conversion (15) of the system is necessary because previously the entire raising / lowering stroke during the alignment of the blade was carried out in the vertical direction, meaning that a free height twice as large as the necessary stroke was required. Now, by converting the direction of the cable (5) by 90° to redirect the raising / lowering stroke during its alignment and insertion, this limitation is relaxed, since the system acts in the horizontal direction towards the inside of the blade (always an area free of obstacles).

[0028] like Figure 6 As shown in , there are two parts at the connection of the blade to the hub: a fixed part (19), which is most likely an extension ring or the bearing itself, and a mobile part corresponding to the root of the blade (9). Auxiliary systems for operators, such as walkways (20), are anchored in the fixed part (19) together with the alignment and insertion systems. Once the center of gravity is aligned and there is enough space between the fixed part (19) and the root of the blade (9), the lifting / lowering system (21) is installed.

[0029] Figure 7a and Figure 7b It is shown how the hydraulic cylinder (14) has a pulley (13) at the end and how the cables (5) pass through the pulley (13) so that when the cylinder (14) extends, the cables (5) hold the roots of the blades (9) together, and when the cylinder (14) retracts the cables (5), they extend and the roots of the blades (9) separate from the hub or its corresponding extension ring (11).

[0030] The anchoring of the alignment and insertion system is carried out by a fixed pin at one end (not shown in the figure) and an adjustable pin (22) at the opposite end. Once the fixed pin is inserted, the adjustable pin (22) is arranged, which rests on a plate (23) that can be moved to find the insertion point of the bearing hole or the extension ring (11).

[0031] By making a section AA on the axis transition element (15) shown in Figure 7, Figure 8 is obtained, in which the interior is shown in detail. The axis transition (15) is formed by an internal pulley (24) guiding the cables (5), and the pulley (13) ensures that both cables (5) support the same load. Outside the structure constituting the axis transition element (15) there is a cylinder (14) and anchor pins at one of its ends, one of which is located on the sliding plate (23). All parts of the system are metal and are anchored in the fixed part (19).

Claims

1. An alignment and insertion system for lowering a blade without using a crane, the alignment and insertion system using a hoist (4), a pulley (10) and a cable (5), all supported and anchored in a rigid beam (3) inside a hub (1), characterized in that: - during the alignment and insertion of the blade, the vertical load of the blade is transferred by 90°, the lowering / lifting stroke of the blade is 200-400 mm, - horizontal transfer of loads by the action of at least two hydraulic elements (14), - using the cables (5) and pulleys (13, 21) to align the centre of gravity of the blade vertically with the centre of the bearing, - all systems are arranged in the lower part of the hub (1), anchored in a fixed part (19) between the hub and the blade, and - Each of the systems comprises three main components: a pulley (13), a hydraulic element (14) and an axis conversion element (15), wherein: - the hydraulic element (14) is arranged between the pulley (13) at one end and the axis conversion element (15) arranged at 90° at the other end, - the axis conversion element (15) is anchored with pins, one of which is fixed and the other of which is an adjustable pin (22), - The cable (5) adjacent to the pulley (13) at one end has a connector (7) before passing through the inner pulley (21) to then pass through the fixed part (19) of the blade joint and be screwed into the hole (8) at the root of the blade (9) through a connecting element (16).

2. The alignment and insertion system according to claim 1, characterized in that The axis conversion element (15) is formed by two internal pulleys (24) that distribute the cables (5) and a pulley (13) that ensures that the two cables (5) support the same load.

3. The alignment and insertion system according to claim 1 or 2, characterized in that An adjustable pin (22) resting on a plate (20) is movable to find the insertion point of the hole (8) at the root of the blade (9) and is large enough to be anchored in the hole of the fixed part (19).

4. The alignment and insertion system according to claim 1, characterized in that The connection element (16) is formed of two parts threaded together: an upper frustoconical part having an internal thread and a lower part (18) having a threaded cylindrical area with a protruding male thread.

5. The alignment and insertion system according to claim 1, characterized in that Once the center of gravity is aligned and there is enough space between the fixing part (19) and the root of the blade (9), a lowering / lifting system (21) is installed, which is fixed at the root of the blade (9).

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