METHOD FOR LIFTING AND LOWERING BLADES WITHOUT USING A CRANE, AND DEVICES USED

Abstract

Disclosed is a method for lifting and lowering blades without using a crane, which uses an aligning and inserting device to solve the problem caused by the tilt and coning of the first/last 200-400 mm of the blade. The device comprises at least one hoist (4) and a pair of cables (5) coordinated by a pulley (10) and screwed to a bearing (12) by means of connecting elements at the ends thereof. The cables (5) are screwed diametrically opposite and as close as possible to the centre of gravity (CG) of the blade. After the initial descent, the blade is secured and a stiffening plate (20) is added to the blade root (13), and the lowering device, formed by a drumless hoist (18) and a set of pulleys (19), is used to lower the blade by means of a passing cable (22) joined to the plate (20). A crane disposed on the ground moves an auxiliary sling placed on the tip (23) of the blade and helps to navigate the transition piece (24) and bottom part (25) of a tower.

Claims

1-10. (canceled)

11. A system for raising and lowering blades without the use of a crane, which uses hoists (4, 18) that are related to pulleys (10, 19) and cables (5, 22), as well as rigid plates (20) screwed to the root of the blade (13), comprising: an alignment and hoisting device used to separate/join the blade in its first 200-400 mm and a lowering device to lower/raise the blade to/from the ground, the alignment and hoisting device including: at least one hoist (4) anchored inside (2) of the hub (1) that reacts the entire load from the inside, at least one cable (5) ended in a connecting element with a diameter smaller than the bearing hole (8), at least one pulley (10) per hoist (4) raising the load capacity and distributing the load between its corresponding inserts (9) and the cables (5) that pass through the holes of the bearing (8) are protected with a centering bushing (16) and are screwed into the insert (9) of the blade root (13) getting as close as possible to the center of gravity (CG), and the lowering device comprising: at least one hoist without drum (18) and at least one set of pulleys (19), anchored to the interior (2) of the hub (1) that react all the load from the inside, and a through cable (22) that is anchored by the connecting element (21) off-center with a stiffening plate (20) screwed to two or more inserts (9) of the blade.

12. The system according to claim 11, wherein the connecting element smaller than the bearing hole (8) is formed by two pieces threaded together: the upper one (14), where the cable (5) is fixed, is frustoconical with a thread inside and the lower one (15) is cylindrical with its threaded outer surface that is screwed to the inserts (9) and with a threaded male protruding to join the upper piece (14).

13. The system according to claim 11, wherein the anchoring inside the hub chassis (2) is carried out with auxiliary beams (3), the pulleys (4) having a set of chains (6) and a turn remover (7), the bushings (16) of the holes (8) are preferably metallic and are anchored to the edge of the bearing (12).

14. The system according to claim 13, wherein the final turn of the blade before reaching the ground is made with the connecting element (21) and its two connections with the cable (22) and with a crane arranged on the ground that moves a guide applied to the tip of the blade (23).

15. The system according to claim 11, wherein the drumless hoist (18) of the lowering device has a through cable (22) tensioned inside the hoist (18) and the rest is released and stored in the inside the hub, near the hub or in the nacelle itself.

16. The system according to claim 15, further comprising conical pins (17) in some of the inserts (9) during the operation of the alignment and insertion device in the raising process.

17. The system according to claim 16, wherein the alignment and hoisting device and the lowering device are connected to the hub-bearing joint or to the blade-bearing joint in three possible ways: directly to the holes of the hub, through beams (3) or through chains.

18. The system according to claim 11, wherein the blade (13) is lowered with the bearing (12) or without the bearing (12).

19. A method of raising and lowering blades without the use of a crane, comprising: raising inside the hub (1) the complete lifting elements, both for the alignment and hoisting device, and for the lowering device; anchor them to the chassis (2) selecting the preferred embodiment, removing several nuts and bolts (11) from the blade bearing (12); pass the cables (5) of the hoists (4) through their respective pulleys (10), pass them through the corresponding hole in the bearing (8) previously protected with a bushing (16) and screw them into the insert (9) of the T-bolt from the root of the blade (13), thread the cables (5) diametrically opposite and as close as possible to the center of gravity (CG), lowering the blade between 200 and 400 mm and fix the blade, screwing the stiffening plate (20) into the blade root (13), join the lowering device with the plate (20) using the connecting element (21); previously crossing the hoist without drum (18) and the double set of pulleys (19) with the through cable (22), release the alignment and hoisting device, raising the auxiliary sling at the tip of the blade (23) with a rope installed in the nacelle and place the sling at the appropriate height, lowering the blade with the help of a guide applied to the tip of the blade (23), rotate the blade before reaching the ground with the off-center connecting element (21) that anchors the stiffening plate (20) and with the guide the tip of the blade (23).

20. The method according to claim 19, wherein during the rise at least one centering pin (17) is added to the inserts (9) of the root of the blade (13) for when the alignment and drilling device is used or in the holes of the fixed bearing of the hub (1), in the case of lowering with bearing (12).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] A brief description will be given below for a series of drawings useful for better understanding the invention and that expressly relate to an embodiment of said invention that is presented as a non-limiting example thereof.

[0026] FIG. 1 shows the rotor in section with the alignment and hoisting device and a part of the blade to be lowered.

[0027] FIG. 2 shows a top view of the blade and its bearing, where the position of the center of gravity CG is indicated.

[0028] FIG. 3 shows the rotor in lateral section with the blade hanging and the angle due to coning and tilt.

[0029] FIG. 4 shows the rotor of the previous figure when it begins its descent, balances and the rotation of the blade is counteracted.

[0030] FIG. 5 shows the cables and the connecting element at their end.

[0031] FIG. 6 represents a section of the bearing and the blade root with a cable screwed on.

[0032] FIG. 7 shows the detail of a section of the blade root and the centering pins.

[0033] FIG. 8 shows the sectioned rotor seen from above, with the lowering device anchored in the hub.

[0034] FIG. 9 shows a plan view of the blade root with a detail of the stiffening bar.

[0035] FIG. 10 shows the rotor in lateral section with details of the anchoring of the lowering device.

[0036] FIGS. 11, 12 and 13 show the blade lowering sequence.

DETAILED DESCRIPTION

[0037] The method described uses several hoists, all of them fixed inside the hub so that the entire load of the blade reacts hanging inside the hub. They are elements limited by the maximum weight allowed to be carried by at least one person working inside a wind turbine. They are small elements that may require pulleys to distribute and equalize the load.

[0038] At least one hoist will be used as a lifting element to form the alignment and hoisting device. And a drumless electric hoist is used for the lowering device.

[0039] As shown in FIG. 1, the hub (1) is sectioned and the interior of the hub (2) is shown. In the upper part of the hub (1), in the fixed track of the connection with the upper blades and using an auxiliary beam (3), the alignment and slot-forming device is anchored by at least one hoist and preferably two. The entire load on the blade reacts by hanging inside the hub (2). According to this practical embodiment, each of the hoists (4) of the alignment and hoisting device works with cables (5) whose greatest requirement is that they have to pass through the holes of the bearing (8) and be anchored in the insert or T-bolt (9) from the root of the blade. To increase the load capacity, since a single insert (9) cannot support the total weight of the blade and the movement of the blade can cause the entire load to be under a single hoist (4), it is necessary to unfold the load with a pulley (10). The pulleys (10) ensure that the two cables support the same load. The interface between hoist (4) and pulley (10) is with a set of chains (6). The interface between the pulley (10) and the blade root insert (9) includes a turn remover (7).

[0040] As shown in FIG. 2, the center of gravity CG (marked with a circle) can be in front or behind the pair of bearing holes (8) that the cables (5) pass through before being threaded into the inserts (9) from the root of the blade. If the blade is opened using rigid elements such as threaded bars or similar, with any displacement of the CG, these elements bend. Working with cables (5) allows the blade to rotate, a rigid element does not. According to this practical embodiment, the points where the pairs of cables are placed are symmetrical. They are practically aligned and as close to the CG as possible. As soon as the rest of the nuts are released from the bolts and the blade is hanging from the cables (5), it tends to rotate due to coning and tilt. There is 5 of tilt. The cables (5) have to be very well coordinated with each other, since there are times when only one of them works.

[0041] For example, a small gust of wind can shift the CG center of gravity and force a single cable to support the entire weight.

[0042] As shown in FIG. 3, the blade has an inclination o with respect to the horizontal plane, due to coning and tilt. When the nuts are removed from the rest of the blade bolts (11) and with the two pairs of cables holding the blade, it is first released from the outermost part of the hub (1). The blade opens correctly since it can rotate thanks to the fact that it hangs from cables, as seen in FIG. 4. And all this without damaging the blade bolts (11) that protrude from the inserts (9) at the root of the blade. The alignment device is capable of supporting the entire blade on a pair of cables (5) thanks to the effect of the pulley (10) that distributes the weight. The cables (5) are very sensitive to twisting and the fact that they act in pairs is flattering.

[0043] The alignment and hoisting device uses cables (5), preferably metallic, to be screwed to the previously emptied inserts (9). FIG. 5 shows how the greatest requirement is that the cables (5) have to cross the bearing track (12) and specifically its holes (8) before being screwed into the insert (9) of the blade root (13). Each cable (5) has a connection element at its end and is made up of two pieces threaded together.

[0044] A truncated-conical piece with a thread inside is the upper piece (14). And the lower piece (15) consists of a threaded cylindrical area with a threaded male protruding. The union is made using the threaded male existing in the cylindrical part (15) and a threaded hole existing inside the truncated-conical part (14). As shown in FIG. 6, the dimensions of the connection element are critical so that they can pass through the bearing holes (8) with a diameter of around 30 mm. The bearing hole (8) is protected with a centering bushing (16) to avoid damaging the cable (5) during its movement. Said bushing (16) is made of a softer metal than the cable (5) and is fixed on the edge of the bearing hole (8).

[0045] FIG. 7 shows a section of the bearing (12) and the root of the blade (13) where the pins (17) used to center the blade in the final approach are located, when it is being raised. The pins (17) are threaded into the insert (9).

[0046] FIG. 8 shows a section of the hub (1), revealing the interior (2) and the lowering device, which is anchored by an auxiliary beam (3) in the fixed track at the junction with the upper blades. The connections of the alignment device and the lowering device can be through beams (3) connected to the hub-bearing joint or to the blade-bearing joint. They can also be through chains connected to the hub-bearing joint or to the blade-bearing joint. And finally, they can be direct connections to the holes-screws of the hub-bearing joint or to the blade-bearing joint.

[0047] The lowering device uses a hoist without drum (18) that, thanks to a certain number of forwards (19) and its reduction effect, manages to work at the necessary load. A stiffening plate (20) is added to the blade root (13). Said plate (20) is coupled with the corresponding cable (22) of the lowering device by means of a connecting element (21) perpendicular to the plate itself. The connecting element (21) can be coupled in the middle of the plate (22) when it is made up of two pieces joined together. The connecting element (21) will have two connections with the cable (22), which favors the rotation of the blade to a horizontal position, as seen in FIG. 9.

[0048] FIG. 10 shows another view of the lowering device formed by the drumless hoist (18) and its double set of pulleys (19). The cable used for the lowering device is a through cable (22). That is, the cable to be used is relaxed and collected inside the hub, near the hub or in the nacelle itself. Only the one inside the hoist (18) is tensioned. The method followed to lower blades without the use of a crane includes the following steps:

[0049] STEP 1Lift the complete lifting elements onto the hub (1) with the operators, both for the alignment and hoisting device, and for the lowering device. Anchor them inside (2) selecting the preferred embodiment.

[0050] STEP 2Remove several nuts and bolts (11) from the root of the blade (13) depending on whether you want to lower the blade or the blade with the bearing (12). Pass the cables (5) of the hoists (4) through their respective pulleys (10), pass them through the corresponding hole in the bearing (8) previously protected with a bushing (17) and screw them into the insert of the T-bolt (9). The cables (5) of the alignment and hoisting device work in pairs and are threaded through the connection element, being arranged symmetrically and closest to the center of gravity (CG) of the blade.

[0051] STEP 3Lower the blade between 200 and 400 mm, making, with the flexibility of the cable, the rotation due to the tilt and coning angle . Fix the blade.

[0052] STEP 4Screw the stiffening plate (20) into the blade root (13). Join the lowering device with the plate (20) using the off-center connecting element (21). The through cable (22) passes through the drumless hoist (18) and its double set of pulleys (19). Release the alignment and hoisting device.

[0053] STEP 5Raise the auxiliary sling at the tip of the blade (23) with a rope installed in the nacelle. Place the sling at the proper height.

[0054] STEP 6Lower the blade with the help of a guide applied to the tip of the blade (23) navigating the transition (24) and the bottom of the tower (25). The final turn of the blade before reaching the ground is done with the off-center connecting element (21) that anchors the stiffening plate (20) and with the auxiliary crane that pulls the sling at the tip of the blade (23).