Performing post-moulding operations on a blade segment of a wind turbine blade

Abstract

The present invention relates to a method of performing at least one post-moulding operation on a blade segment (70) of a wind turbine blade. The method comprises the providing a holding device (88) for supporting the blade segment (70) at its spar structure (62), the holding device (88) comprising a coupling member (90) for engaging the spar structure (62). The blade segment (70) is held with the holding device (88) such that the spar structure (62) of the blade segment (70) is engaged by the coupling member (90), and performing at least one post-moulding operation on the shell structure (82) of the blade segment (70).

Claims

1. A method of performing at least one post-moulding operation on a spanwise blade segment (70) of a wind turbine blade, the blade segment (70) comprising a shell structure (82) with an open end (86) and a spar structure (62) arranged at least partly within the shell structure (82) and protruding from the open end (86), the method comprising the steps of: providing a holding device (88) for supporting the blade segment (70) at the spar structure (62) thereof, the holding device (88) comprising a coupling member (90) for engaging the spar structure (62); holding the blade segment (70) with the holding device (88) such that the spar structure (62) of the blade segment (70) is engaged by the coupling member (90); and performing at least one post-moulding operation on the shell structure (82) of the blade segment (70), wherein the shell structure (82) is not directly engaged by the holding device (88), such that the shell structure (82) is freely accessible, wherein the holding device (88) further comprises actuation means for rotating the coupling member (90) around a longitudinal axis (Lo) thereof, wherein the actuation means comprises a motor.

2. The method according to claim 1, wherein the blade segment (70) is a spanwise blade segment (70).

3. The method according to claim 2, wherein the blade segment (70) includes the tip of the wind turbine blade.

4. The method according to claim 1, wherein the blade segment (70) is held in a substantially horizontal position above a ground surface.

5. The method according to claim 1, wherein the coupling member (90) comprises a sheath element for receiving at least part of the spar structure (62).

6. The method according to claim 5, wherein the sheath element is rotatable around a longitudinal axis thereof.

7. The method according to claim 1, wherein the spar structure (62) is fastened to the coupling member (90) by one of more pins extending through the coupling member (90) and the spar structure (62).

8. The method according to claim 1, wherein the holding device (88) further comprises a counterweight for balancing the weight of the supported blade segment (70).

9. The method according to claim 1, wherein the holding device (88) further comprises a bearing for rotatably receiving a spanwise extending appendage of the spar structure (62).

10. The method according to claim 1, wherein the holding device (88) further comprises a movable support member comprising a plurality of wheels.

11. The method according to claim 1, wherein the post-moulding operation is selected from a shell repair operation, a shell grinding operation or a shell coating operation.

Description

DESCRIPTION OF THE INVENTION

(1) The invention is explained in detail below with reference to an embodiment shown in the drawings, in which

(2) FIG. 1 shows a wind turbine,

(3) FIG. 2 shows a schematic view of a wind turbine blade.

(4) FIG. 3 shows a schematic view of a cross-section of a wind turbine blade,

(5) FIG. 4 is a perspective view of blade segments of a wind turbine blade according to the present invention,

(6) FIG. 5 is a schematic side view of a support assembly of the present invention in a disassembled state.

(7) FIG. 6 is a schematic side view of a support assembly of the present invention in an assembled state, and

(8) FIG. 7 is a partial perspective view illustrating a blade segment and a coupling member according to the present invention.

DETAILED DESCRIPTION

(9) FIG. 1 illustrates a conventional modern upwind wind turbine according to the so-called Danish concept with a tower 4, a nacelle 6 and a rotor with a substantially horizontal rotor shaft. The rotor includes a hub 8 and three blades 10 extending radially from the hub 8, each having a blade root 16 nearest the hub and a blade tip 14 farthest from the hub 8. The rotor has a radius denoted R.

(10) FIG. 2 shows a schematic view of a wind turbine blade 10. The wind turbine blade 10 has the shape of a conventional wind turbine blade and comprises a root region 30 closest to the hub, a profiled or an airfoil region 34 farthest away from the hub and a transition region 32 between the root region 30 and the airfoil region 34. The blade 10 comprises a leading edge 18 facing the direction of rotation of the blade 10, when the blade is mounted on the hub, and a trailing edge 20 facing the opposite direction of the leading edge 18.

(11) The airfoil region 34 (also called the profiled region) has an ideal or almost ideal blade shape with respect to generating lift, whereas the root region 30 due to structural considerations has a substantially circular or elliptical cross-section, which for instance makes it easier and safer to mount the blade 10 to the hub. The diameter (or the chord) of the root region 30 may be constant along the entire root area 30. The transition region 32 has a transitional profile gradually changing from the circular or elliptical shape of the root region 30 to the airfoil profile of the airfoil region 34. The chord length of the transition region 32 typically increases with increasing distance r from the hub. The airfoil region 34 has an airfoil profile with a chord extending between the leading edge 18 and the trailing edge 20 of the blade 10. The width of the chord decreases with increasing distance r from the hub.

(12) A shoulder 40 of the blade 10 is defined as the position, where the blade 10 has its largest chord length. The shoulder 40 is typically provided at the boundary between the transition region 32 and the airfoil region 34. FIG. 2 also illustrates the longitudinal extent L, length or longitudinal axis of the blade.

(13) It should be noted that the chords of different sections of the blade normally do not lie in a common plane, since the blade may be twisted and/or curved (i.e. pre-bent), thus providing the chord plane with a correspondingly twisted and/or curved course, this being most often the case in order to compensate for the local velocity of the blade being dependent on the radius from the hub.

(14) The blade is typically made from a pressure side shell part 36 and a suction side shell part 38 that are glued to each other along bond lines at the leading edge 18 and the trailing edge of the blade 20.

(15) FIG. 3 shows a schematic view of a cross section of the blade along the line 1-1 shown in FIG. 2. As previously mentioned, the blade 10 comprises a pressure side shell part 36 and a suction side shell part 38. The pressure side shell part 36 comprises a spar cap 41, also called a main laminate, which constitutes a load bearing part of the pressure side shell part 36. The spar cap 41 comprises a plurality of fibre layers 42 mainly comprising unidirectional fibres aligned along the longitudinal direction of the blade in order to provide stiffness to the blade. The suction side shell part 38 also comprises a spar cap 45 comprising a plurality of fibre layers 46. The pressure side shell part 38 may also comprise a sandwich core material 43 typically made of balsawood or foamed polymer and sandwiched between a number of fibre-reinforced skin layers. The sandwich core material 43 is used to provide stiffness to the shell in order to ensure that the shell substantially maintains its aerodynamic profile during rotation of the blade. Similarly, the suction side shell part 38 may also comprise a sandwich core material 47.

(16) The spar cap 41 of the pressure side shell part 36 and the spar cap 45 of the suction side shell part 38 are connected via a first shear web 50 and a second shear web 55. The shear webs 50, 55 are in the shown embodiment shaped as substantially I-shaped webs. The first shear web 50 comprises a shear web body and two web foot flanges. The shear web body comprises a sandwich core material 51, such as balsawood or foamed polymer, covered by a number of skin layers 52 made of a number of fibre layers. The blade shells 36, 38 may comprise further fibre-reinforcement at the leading edge and the trailing edge. Typically, the shell parts 36, 38 are bonded to each other via glue flanges.

(17) FIG. 4 is a schematic perspective view of two spanwise segments 68, 70 of a wind turbine blade 10 according to the present invention. In this embodiment, the blade comprises a first blade segment 68, such as a root segment, and a second blade segment 70, such as a tip segment. A spar structure 62 is arranged within the second blade segment 70 and protrudes from the same.

(18) FIGS. 5 and 6 illustrate a support assembly 80 for performing a post-moulding operation on a blade segment of a wind turbine blade according to the present invention. FIG. 5 shows a dissembled state, whereas FIG. 6 shows an assembled state. The support assembly 80 comprises a spanwise blade segment 70 of a segmented wind turbine blade. The blade segment 70 comprises a shell structure 82 having an outer shell surface 84 and comprising the tip 14 of the later wind turbine blade. The blade segment 70 has an open end 86, as seen in FIGS. 4 and 7, and a spar structure 62 arranged at least partly within the shell structure 82 and protruding from the open end 86.

(19) The support assembly 80 comprises a holding device 88 for supporting the blade segment 70 at its spar structure 62. The holding device 88 comprises a coupling member 90 for engaging the spar structure 62. In the illustrated embodiment the coupling member 90 has the form of a sheath element that receives part of the spar structure 62 therein. The sheath element is advantageously rotatable around its longitudinal axis Lo for rotating the blade segment 70 during or in between post-moulding operations.

(20) As seen in FIG. 6, the blade segment is held in a substantially horizontal position above a ground surface. Thus, the outer shell surface is accessible for post-moulding operations such as a shell repair operation, a shell grinding operation or a shell coating operation. The holding device 88 further comprises actuation means including chain-type rotation means 94 and a motor 92 for driving the chain for rotating the coupling member around its longitudinal axis Lo. The holding device 88 further comprises a counterweight 96 for balancing the weight of the supported blade segment 70.

(21) Also, the spar structure is fastened to the coupling member 90 by a pin 95 extending through the coupling member 90 and the spar structure 62. This is illustrated in the partial perspective view of FIG. 7 showing an embodiment with a spar structure 62 in the form of a box spar and a coupling member 90 having a corresponding cross section for receiving the box spar (remaining parts of holding device not shown). Alignable holes 90a, 62a may be provided in the coupling member 90 and the spar structure 62 to receive the pin 95. Thus, during rotation of the coupling member 90, the relative position of the spar structure to the coupling member is fixed.

(22) As also seen in FIGS. 5 and 6, the holding device 88 comprises a bearing 97 for rotatably receiving a spanwise extending appendage 63 of the spar structure 62. In addition, the holding device 88 comprises a movable support member 100, such as a roll table or wagon, comprising a plurality of wheels 102.

(23) The invention is not limited to the embodiments described herein and may be modified or adapted without departing from the scope of the present invention.

LIST OF REFERENCE NUMERALS

(24) 4 tower 6 nacelle 8 hub 10 blades 14 blade tip 16 blade root 18 leading edge 20 trailing edge 30 root region 32 transition region 34 airfoil region 36 pressure side shell part 38 suction side shell part 40 shoulder 41 spar cap 42 fibre layers 43 sandwich core material 45 spar cap 46 fibre layers 47 sandwich core material 50 first shear web 51 core member 52 skin layers 55 second shear web 56 sandwich core material of second shear web 57 skin layers of second shear web 60 filler ropes 62 spar structure 63 appendage 68 first blade segment 70 second blade segment 80 support assembly 82 shell structure 84 outer shell surface 86 open end of blade segment 88 holding device 90 coupling member 92 motor 94 chain-type rotation means 95 pin 96 counterweight 97 bearing 99 holes 100 roll table 102 wheels L length r distance from hub R rotor radius