Method for mounting a rotor blade and assembly arrangement

Abstract

The invention relates to a method for mounting a rotor blade with a rotor blade shell and an internal space defined by the rotor blade shell, by at least one rotor blade clamp being applied around the outside of the rotor blade shell, by means of which at least one clamping force is exerted from the outside to the rotor blade shell, directed into the internal space by at least one expansion device being introduced into the internal space, by the expansion device inside the internal space being moved into at least one segment of the rotor blade around which the at least one rotor blade clamp is applied, by the at least one expansion device being expanded inside the at least one segment until at least one outwardly-acting counteracting force is exerted from the inside on the rotor blade shell.

Claims

1. A method for mounting a rotor blade (20) with a rotor blade shell and an internal space (53) defined by the rotor blade shell, the mounting performed by at least one rotor blade clamp (10) being applied around the outside of the rotor blade shell, by means of which at least one clamping force is exerted from the outside on the rotor blade shell, directed into the internal space (53), by at least one expansion device (30) being introduced into the internal space (53), by the expansion device (30) inside the internal space (53) being moved into at least one segment (26) of the rotor blade (20) around which the at least one rotor blade clamp (10) is applied, by the at least one expansion device (30) being expanded inside the at least one segment (26) until at least one outwardly-acting counteracting force is exerted from the inside on the rotor blade shell, which at least partially compensates the at least one clamping force.

2. The method as claimed in claim 1, wherein a load is measured inside the at least one segment (26).

3. The method as claimed in claim 2, wherein a deformation is measured inside the at least one segment (26).

4. The method as claimed in claim 1, wherein the measurement values are supplied to a controller unit (40) and are evaluated there and control values are determined and supplied to the at least one expansion device (30), and the at least one expansion device (30) is expanded.

5. The method as claimed in claim 1, wherein the rotor blade (20), together with the at least one expanded expansion device (30), is pulled up to the nacelle of a wind turbine, and mounted there, and the at least one rotor blade clamp (10) and the at least one expansion device (30) are then released.

6. The method as claimed in claim 5, wherein the at least one expansion device (30) is secured to a rope, after mounting the rotor blade (20) is lowered with a tip (27), and the at least one expansion device (30) is pulled out of the internal space (53) on the rope after release of the expansion device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a front view of an open rotor blade clamp,

(2) FIG. 2 shows a rotor blade with a mounted rotor hub and a rotor blade clamp according to FIG. 1 applied to the rotor blade,

(3) FIG. 3 shows a side view of a spreading device according to the invention,

(4) FIG. 4 shows a side view, in partial section, of the contracted spreading device according to FIG. 3, between the main webs of the rotor blade,

(5) FIG. 5 shows the spread spreading device according to FIG. 3 inside a segment of the rotor blade clamp clamped around the rotor blade,

(6) FIG. 6 shows a view in section of the arrangement in FIG. 5 along the line VI-VI.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(7) FIG. 1 shows a rotor blade clamp 10. It has an upper pivotable sky-side clamping arm 11 and a lower ground-side clamping arm 12. The upper clamping arm 11 is arranged on the ground-side clamping arm 12 so that it can be pivoted as desired at a first hinge 13 or a second opposite hinge 14 to open and close the rotor blade clamp 10. The rotor blade clamp 10 has a locking mechanism 16 by means of which the sky-side and the ground-side clamping arms 11, 12 can be locked in a fixed position relative to each other.

(8) The inner sides of the sky-side and the ground-side clamping arms 11, 12 are each provided with a sky-side and a ground-side impact protection guard 17, 18, respectively, which counteract damage to an outer surface of a rotor blade 20 gripped inside the rotor blade clamp 10.

(9) FIG. 2 shows a rotor blade 20, ready for mounting, with a rotor hub 21 and a closed rotor blade clamp 10 according to FIG. 1.

(10) During the mounting of a rotor on a wind turbine, a first rotor blade 20 is first mounted on the rotor hub 21. The rotor blade 20 is attached to the rotor hub 21 in a horizontal position directly next to the already erected tower (not shown) of the wind turbine with a nacelle rotatably mounted on the tower.

(11) The rotor blade clamp 10 can, according to FIG. 1, be folded open by means of the first and second hinges 13, 14 on both sides transverse to a longitudinal direction L of the clamped rotor blade 20. The opened rotor blade clamp 10 is arranged on a vertically extendable support device, the Merlot, and, in the open state, is moved on the ground onto the rotor blade 20 until the rotor blade 20 bears with its ground-side outer wall against the ground-side impact protection guard 18 of the ground-side clamping arm 12 of the rotor blade clamp 10. The rotor blade clamp 10 is then closed by the sky-side clamping arm 11 being pivoted and locked over a segment 26 of the rotor blade 20, bearing against the rotor blade clamp 10. The rotor blade clamp 10 is thus firmly clamped to the rotor blade 20 by tensioning the locking mechanism 16. A sufficiently great clamping force must thus be exerted on the outer wall of the rotor blade 20 to make it difficult for the rotor blade 20 to slip out of the rotor blade clamp 10, and preferably prevent it, during the mounting or dismantling process.

(12) Alternatively, the already closed rotor blade clamp 10 can be threaded over a tip 27 of the rotor blade 20 and then be pushed in the longitudinal direction L in the closed state over the rotor blade 20 until it has been pushed into the segment 26 of the rotor blade 20 which is provided for the application of the rotor blade clamp 10.

(13) Three hoisting ropes 22, 23, 24 are provided for hoisting up the rotor blade 20. In other embodiments of the invention, it is of course also conceivable to use a different number of hoisting ropes 22, 23, 24. The first hoisting rope 22 is fastened directly to the rotor hub 21. The second and the third hoisting ropes 23, 24 are fastened opposite each other to the rotor blade clamp 10 next to the first and second hinges 13, 14.

(14) The rotor hub 21 and the single rotor blade 20 are hoisted up, by means of a crane (not shown) having a crane arm, from the horizontal position next to the tower by the three hoisting ropes 22, 23, 24 vertically from the ground, preferably from the earth, and hoisted up from there to the nacelle. During the hoisting procedure, the rotor blade 20 according to FIG. 2 remains constantly in an essentially horizontal position.

(15) When tensioned, the rotor blade clamp 10 exerts a clamping force which acts from the outside into an internal space 53 formed between the two rotor blade shells. The clamping force can result in damage to the relatively light and delicate, in particular internal structure of the rotor blade 20, in particular to the main webs 51, 52 which run parallel to each other inside the internal space 53 of the rotor blade 20 in the longitudinal direction L from a rotor blade root 28 to the tip 27 of the rotor blade 20. The clamping force can, however, also or additionally cause other damage, for example to the outer skin. The damage can go undiscovered as inter-fiber fractures in the laminate or as cracks in the bonds of the main webs 51, 52 to a sky-side main chord 54 and a ground-side main chord 55 of the two rotor blade half-shells of the rotor blade 20.

(16) A spreading device 30 according to FIGS. 3, 4, 5, 6 is provided to prevent damage to the internal structure of the rotor blade 20. The spreading device 30 shown in FIGS. 3, 4, 5, 6 is shown only by way of example. A wide variety of embodiments of the spreading device are conceivable.

(17) FIG. 3 shows the spreading device 30 with a frame, having four wheels 36, with a motor drive 34 by means of which the spreading device 30 can be moved through between the two main webs 51, 52, horizontally in the longitudinal direction L of the rotor blade 20. To do this, the width of the spreading device 30 perpendicular to the direction of travel is such that it passes between the two main webs 51, 52. It can be displaced back and forth in the longitudinal direction L. The motor drive 34 enables the spreading device 30 to travel in a folded-together state in the longitudinal direction L between the two main webs 51, 52 from the rotor blade root 28 into the tip 27 of the rotor blade 20. The motor drive 34 comprises an electromotor 35 with wheels 36 driven by it. The spreading device 30 travels back and forth in the longitudinal direction L on the inner wall of the ground-side main chord 55 of the rotor blade 20. The spreading device 30 according to FIG. 3 has two opposite pressure pads 31, 32. The two pressure pads 31, 32 can be moved toward and apart from each other by means of a spreadable and refoldable spreading rod 33. The spreading device 30 has a spreading drive 37 for spreading and folding up the spreading rod 33. The spreading drive 37 can also be driven via the electromotor 35.

(18) The spreading device 30 is introduced in FIG. 2 into the internal space 53 of the rotor blade 20 between the two main webs 51, 52 via the mounted rotor hub 21 and the rotor blade root 28 which is open facing the rotor hub 21, and, with the rotor blade 20 in a horizontal position, displaced there by the motor drive 34 into the segment 26 toward the tip 27 of the rotor blade 20 according to FIG. 4, in which the rotor blade clamp 10 is clamped around the outside of the rotor blade 20. Inside the segment 26 in which the rotor blade clamp 10 is clamped around the outside of the rotor blade 20, the spreading device 30 according to FIG. 5 is spread by means of the spreading drive 37 until it presses from the inside with the two pressure pads 31, 32 against the inner walls of the main chords 54, 55 and thus counteracts the clamping force, acting from the outside, of the rotor blade clamp 10 with a counteracting force.

(19) A controller unit 40 is provided to control the counteracting force and the correctly proportioned size of the counteracting force. The controller unit 40 is positioned outside the rotor blade 20 during its operation.

(20) FIG. 6 shows the wiring of the controller unit 40 in a longitudinal section along the rotor blade 20. The controller unit 40 is, on the one hand, connected in a data-transferring manner to the motor drive 34 and to the spreading drive 37 of the spreading device 30 and, on the other hand, connected in a data-transferring manner to sensors integrated in the rotor blade 20, such as strain gauges 41 or the like.

(21) The strain gauges 41 are provided in the region of or in the bonds of the main webs 51, 52 on the two opposite main chords 54, 55. They can also be integrated into the laminate of the main webs 51, 52 or of the rotor blade half-shells. Each of the strain gauges 41 is connected to a respective electrical contact 62 arranged on the rotor blade root 28 by a respective electrical cable 61. The strain gauges 41 determine the forces acting on the main webs 51, 52 and the bonds via deformation of the main webs 51, 52 caused by the clamping force, acting from the outside, of the rotor blade clamp 10. The controller unit 40 calculates, from the measurement values of the strain gauges 41, the counteracting force with which the spreading device 30 needs to be pressed from the internal space 53 against the two opposite inner walls of the main chords 54, 55, so that its total force resulting from the addition of the counteracting force and the clamping force is as low as possible and/or the deformations measured by the strain gauges 41 are minimized. The controller unit 40 is designed as a control loop so that, when the measured load which is exerted by the main webs 51, 52 and the bonds of the main webs 51, 52 on the main chords 54, 55 becomes greater, the counteracting force is increased until the loads measured at the strain gauges 41 are minimized and then the spreading device 30 is adjusted.

(22) Once the adjustment of the spreading device 30 is complete, the rotor blade 20 is hoisted up. The rotor blade 20, together with the rotor blade clamp 10 and the spread spreading device 30 according to FIG. 5, is hoisted up vertically from the horizontal position on the ground to the level of the nacelle, and at the level of the nacelle the rotor blade hub 21 according to FIG. 2 is rotated by 90 and mounted on the nacelle.

(23) After the rotor blade hub 21 has been mounted on the nacelle, the clamping force of the rotor blade clamp 10 and the counteracting force of the spreading device 30 are reduced simultaneously, and the released rotor blade clamp 10 can be pulled off over the tip 27 of the rotor blade 20. The blade clamp 10 can also be completely opened and thus released from the rotor blade 20 and lowered again. At the same time, before or after, the released spreading device 30 is extracted from the rotor blade 20 arranged essentially horizontally at the level of the nacelle, between the main webs 51, 52 from the segment 26, by means of its own spreading drive 34.

(24) The spreading device 30 is then used to mount a second rotor blade. The same applies to the rotor blade clamp 10. In order to mount the second rotor blade, the first rotor blade 20, together with the rotor hub 21, is first rotated by 120 so that the rotor blade connection of the second rotor blade of the already mounted rotor blade hub 21 is oriented in a horizontal position. The second rotor blade, lying horizontally on the ground, together with the rotor blade clamp 10, is oriented horizontally and hoisted up vertically, with the spreading device 30 inserted and adjusted, by means of the second and the third hoisting rope 23, 24 and by means of the first hoisting rope 22 fastened directly to the rotor blade root of the second rotor blade. It is hoisted up to the level of the rotor blade connection on the nacelle. The second rotor blade is then mounted on a second connection of the rotor hub 21, and the rotor blade clamp 10 and spreading device 30 are, as with the first rotor blade 20, in turn released.

(25) The corresponding procedure is then repeated for a third rotor blade.

LIST OF REFERENCE NUMERALS

(26) 10 rotor blade clamp 11 sky-side clamping arm 12 ground-side clamping arm 13 first hinge 14 second hinge 16 locking mechanism 17 sky-side impact protection guard 18 ground-side impact protection guard 20 rotor blade 21 rotor hub 22 first hoisting rope 23 second hoisting rope 24 third hoisting rope 26 segment 27 tip 28 rotor blade root 30 spreading device 31 pressure pad 32 pressure pad 33 spreading rod 34 motor drive 35 electromotor 36 wheel 37 spreading drive 40 controller unit 41 strain gauges 51 main web 52 main web 53 internal space of the rotor blade 54 sky-side main chord 55 ground-side main chord 61 electrical cable 62 electrical contact L longitudinal direction