METHOD FOR MANUFACTURING A WIND TURBINE BLADE AND MOLD FOR MANUFACTURING A WIND TURBINE BLADE

Abstract

A method for manufacturing a wind turbine blade including: arranging an upper mold on a lower wherein a dry fiber lay-up is arranged in the upper mold or in the upper mold and the lower mold, applying vacuum to a space between the upper and lower molds, and infusing the dry fiber lay-up in the upper and/or lower molds with resin through at least one upper resin inlet arranged at an upper portion of the upper mold. Having the at least one upper resin inlet of the upper mold improves the vacuum-assisted resin infusion. Resin provided through the at least one upper resin inlet has to be raised by a smaller height to reach the top of the mold. A resin flow of the resin provided through the at least one upper resin inlet is supported in a downward direction by the gravitational force.

Claims

1. A method for manufacturing a wind turbine blade, comprising arranging an upper mold on a lower mold, wherein a dry fiber lay-up arranged in the upper mold or in the upper mold and the lower mold; applying vacuum to a space between the upper mold and the lower mold; and infusing the dry fiber lay-up in the upper mold and/or the lower molds with resin, wherein the resin is at least partially provided through at least one upper resin inlet arranged at an upper portion of the upper mold.

2. The method according to claim 1, wherein: at least one further resin inlet is arranged at the upper mold or the lower mold and at a different height than the at least one upper resin inlet, and the dry fiber lay-up in the upper mold and the lower mold is infused, in addition to the resin being provided through the at least one upper resin inlet, with resin being provided through the at least one further resin inlet.

3. The method according to claim 1, further comprising detecting a position of the resin during a flow through the dry fiber lay-up in the upper mold and the lower mold.

4. The method according to claim 2, wherein a position of the resin is detected at the at least one upper resin inlet, at the at least one further resin inlet and/or at a lower portion or a bottom portion of the lower mold.

5. The method according to claim 2, wherein: the infusion of the dry fiber lay-up in the upper mold and the lower mold is started by providing resin through the at least one upper resin inlet, and the infusion of the dry fiber lay-up the upper mold and the lower mold is continued, after providing resin through the at least one upper resin inlet, by providing resin through the at least one further resin inlet.

6. The method according to claim 2, wherein: the infusion of the dry fiber lay-up in the upper mold and the lower molds is started by providing resin through the at least one further resin inlet, and the infusion of the dry fiber lay-up in the upper mold and the lower mold is continued, after providing resin through the at least one further resin inlet, by providing resin through the at least one upper resin inlet.

7. The method according to claim 5, further comprising detecting when the resin, provided through the one of the at least one upper resin inlet and the at least one further resin inlet has flown to the other one of the at least one upper resin inlet and the at least one further resin inlet, and in response to the detecting, providing resin through the other one of the at least one upper resin inlet and the at least one further resin inlet.

8. The method according to claim 1, wherein an inlet pressure of the resin being provided through the at least one upper resin inlet and/or the at least one further resin inlet is controlled to a pressure below atmospheric pressure.

9. The method according to claim 1, wherein an inlet pressure of the resin being provided through the at least one upper resin inlet and/or the at least one further resin inlet is controlled such that a pressure inside the space between the upper mold and the lower mold is controlled to a pressure below atmospheric pressure.

10. The method according to claim 8, wherein the inlet pressure of the resin being provided through the at least one upper resin inlet and/or the at least one further resin inlet is reduced during a flow of the resin through the dry fiber lay-up in the upper mold and the lower mold.

11. The method according to claim 1, further comprising extracting excess resin from a lower portion or a bottom portion of the upper mold, from the lower mold and/or from a lower portion or a bottom portion of the lower mold.

12. The method according to claim 1, wherein the at least one upper resin inlet is arranged exclusively at a lengthwise section of the upper mold configured for manufacturing an inboard blade section of the wind turbine blade.

13. The method according to claim 1, wherein: the at least one upper resin inlet is arranged at a height above a lower end of the upper mold corresponding, as seen in cross-section, to an angle larger than 15 degrees, larger than 30 degrees, larger than 40 degrees, larger than 45 degrees, larger than 60 degrees, larger than 75 degrees and/or larger than 80 degrees, and the angle is defined between a horizontal plane including the lower end of the upper mold and a plane intersecting a longitudinal axis of the manufactured blade and the at least one upper inlet.

14. A mold for manufacturing a wind turbine blade, comprising a lower mold and an upper mold, wherein at least one upper resin inlet is arranged at an upper portion of the upper mold.

Description

BRIEF DESCRIPTION

[0083] Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

[0084] FIG. 1 shows a wind turbine according to an embodiment;

[0085] FIG. 2 shows a cross-section view of a mold for manufacturing a wind turbine blade of the wind turbine of FIG. 1, according to a first embodiment;

[0086] FIG. 3 shows a view similar as FIG. 2 but with resin partly infused into a fiber lay-up arranged in the mold;

[0087] FIG. 4 shows a view similar as FIG. 2 but with an apparatus for extracting excess resin;

[0088] FIG. 5 shows a perspective view of a variant of the mold of FIG. 2;

[0089] FIG. 6 shows a perspective view of a variant of the mold of FIG. 2;

[0090] FIG. 7 shows a flowchart illustrating a method for manufacturing the wind turbine blade of the wind turbine of FIG. 1 using the mold of FIG. 2, according to a first embodiment;

[0091] FIG. 8 shows a cross-section view of a mold for manufacturing a wind turbine blade of the wind turbine of FIG. 1, according to a second embodiment;

[0092] FIG. 9 shows a flowchart illustrating a method for manufacturing the wind turbine blade of the wind turbine of FIG. 1 using the mold of FIG. 8, according to a second embodiment; and

[0093] FIG. 10 illustrates, in cross-section, a geometrical arrangement of resin inlets of the mold of FIG. 2 according to the first embodiment and of the mold of FIG. 8 according to the second embodiment.

DETAILED DESCRIPTION

[0094] In the Figures, like reference numerals designate like or functionally equivalent elements, unless otherwise indicated.

[0095] FIG. 1 shows a wind turbine 1 according to an embodiment. The wind turbine 1 comprises a rotor 2 having one or more blades 3 connected to a hub 4. The hub 4 is connected to a generator (not shown) arranged inside a nacelle 5. During operation of the wind turbine 1, the blades 3 are driven by wind to rotate and the wind's kinetic energy is converted into electrical energy by the generator in the nacelle 5. The nacelle 5 is arranged at the upper end of a tower 6 of the wind turbine 1. The tower 6 is erected on a foundation 7 such as a monopile or tripile. The foundation 7 is connected to and/or driven into the ground or seabed.

[0096] In the following an improved method for manufacturing a wind turbine blade 3 according to a first embodiment is described with respect to FIGS. 2 to 7.

[0097] FIG. 2 shows a mold 8 in cross-section for manufacturing one of the wind turbine blades 3 of FIG. 1. The mold 8 comprises a lower mold 9 and an upper mold 10.

[0098] In step S1 of the method, a dry fiber lay-up 11 is arranged in the upper and lower molds 9, 10. The fiber lay-up 11 may also comprise a core material and/or reinforcement beams (not shown). Furthermore, a shear web 12 is arranged in the mold 8.

[0099] Furthermore, the fiber lay-up 11 is covered with one or more vacuum bags 13.

[0100] In step S2 of the method, the upper mold 10 is arranged on the lower mold 9. FIG. 2 shows the mold 8 in a closed state in which the upper mold 10 is already arranged on the lower mold 9.

[0101] It is noted that the mold 8 may further comprise one or more mold cores 14. In the example of FIG. 2 two mold cores 14 are shown. The mold cores 14 allow an improved arrangement of the dry fiber lay-up 11 in the mold 8, particularly in the upper mold 10, and of the shear web 12. Further, the upper mold 10 can be more easily arranged on the lower mold 9. In the case of having one or more mold cores 14, each of them is, for example, covered by one of the vacuum bags 14.

[0102] In step S3 of the method, a vacuum is generated in a space 15 covered by the vacuum bag 13. The space 15 is, in particular a space between the upper and lower molds 10, 9 and the one or more vacuum bags 13. The space 15 may include an area around the shear web 12.

[0103] The upper mold 10 comprises at least one upper resin inlet channel 16. In the example shown in FIG. 2, there are two upper resin inlet channels 16 arranged between the dry fiber lay-up 11 and the vacuum bag 13. The two upper resin inlet channels 16 are arranged on the mold cores 14 covered by the vacuum bags 13. Further, the two upper resin inlet channels 16 in FIG. 2 are arranged symmetrically with respect to a vertical center line V of the mold 8.

[0104] Each of the upper resin inlet channels 16 has an elongated structure arranged along a longitudinal direction L1 of the mold 8 (the longitudinal direction L1 is illustrated in FIG. 5). Further, each of the upper resin inlet channels 16 comprises an opening at its top along its length through which resin 17 can be provided and infused into the fiber lay-up 11.

[0105] In step S4 of the method, a supply of resin 17 to the at least one upper resin inlet channel 16 is started, and resin 17 is provided through the opening of the at least one upper resin inlet channel 16 (FIG. 3).

[0106] The resin provided through the openings of the two upper resin inlet channels 16 is delivered with an inlet pressure below atmospheric pressure. The inlet pressure is, for example, slightly below atmospheric pressure. The inlet pressure has, for example, a value in the range of 0.6 to 0.95 bar, in particular in the range of 0.8 to 0.95 bar, even more particularly a value of about 0.9 bar.

[0107] In step S5 of the method, the resin 17 provided through the openings of the upper resin inlet channels 16 is infused into the fiber lay-up 11 due to the vacuum generated in the space 15. In particular, the resin 17 provided through the openings of the upper resin inlet channels 16 is infusing the fiber layup 11 in the upper mold 10.

[0108] The mold 8 comprises at least one further resin inlet channel 18, 19. In the example shown in FIGS. 2-4, the mold 8 comprises two further resin inlet channels 18, 19 arranged at a connection region between the upper mold 10 and the lower mold 9. The further resin inlet channel 18 is, for example, a trailing-edge resin inlet channel. The further resin inlet channel 19 is, for example, a leading-edge resin inlet channel. Each of the further resin inlet channels 18, 19 has an elongated structure comprising an opening along its length.

[0109] The two further resin inlet channels 18, 19 in the example of FIG. 2-4 are arranged between the upper/lower mold 10, 9 and the dry fiber lay-up 11. In another example, the at least one further resin inlet channel 18, 19 may be arranged between the dry fiber lay-up 11 and the vacuum bag 13. In even another example, there may be arranged at least one further resin inlet channel 18, 19 between the upper/lower mold 10, 9 and the dry fiber lay-up 11 (e.g., as shown in FIGS. 2-4), and there may be in addition arranged at least one further resin inlet channel between the dry fiber lay-up 11 and the vacuum bag 13.

[0110] In step S6 of the method, the position of the resin 17 (FIG. 3) is detected by means of one or more sensors 20, 21 at the at least one further resin inlet 18, 19.

[0111] The sensors 20, 21 in the example of FIGS. 2-4 are arranged within the lower mold 9. The lower mold 9 comprises several boreholes 22, 23 having each an opening towards an inner surface 24 of the lower mold 9. Each of the sensors 20, 21 is arranged in one of the boreholes 22, 23 such that the respective sensor 20, 21 is flush with the inner surface 24 of the lower mold 9. The sensors 20, 21 could also be configured and arranged differently, for example as stickers at the inner surface 24 (i.e. without boreholes in the mold 8).

[0112] The sensors 20, 21 are, for example, pressure sensors. The sensors 20, 21 could also be other sensors capable of detecting the resin 17.

[0113] The sensor 20 is arranged below the further resin inlet channel 18 to detect if the resin 17 provided through the openings of the upper resin inlet channels 16 has passed the further resin inlet channel 18.

[0114] The sensor 21 is arranged below the further resin inlet channel 19 to detect if the resin 17 provided through the upper resin inlet channels 16 has passed the further resin inlet channel 19.

[0115] In step S7 of the method, resin 17 is provided through the openings of the further resin inlet channels 18 and 19, if it was detected by means of the sensors 20, 21 that a flow front of the resin 17 provided through the upper resin inlet channels 16 has reached and passed the further resin inlet channels 18 and 19.

[0116] In detail, a supply of resin 17 to the further resin inlet channels 18 and 19 is started in step S7 and the resin 17 is provided through the openings of the further resin inlet channels 18, 19 with an inlet pressure below atmospheric pressure. The resin provided through the further resin inlet channels 18, 19 is, for example, delivered with an inlet pressure slightly below atmospheric pressure. The inlet pressure has, for example, a value in the range of 0.6 to 0.95 bar, in particular in the range of 0.8 to 0.95 bar, even more particularly a value of about 0.9 bar.

[0117] Furthermore, a supply of resin 17 to the upper resin inlet channels 16 may be closed in step S7.

[0118] In step S8 of the method, the fiber layup 11 in the lower mold 9 is infused with resin 17 provided through the upper resin inlet channels 16 and the further resin inlet channels 18, 19.

[0119] In step S9 of the method, the inlet pressure of the resin 17 provided through the further resin inlet channels 18, 19 is reduced. The inlet pressure of the resin 17 may be reduced continuously or may be reduced stepwise. The inlet pressure of the resin 17 is reduced in order to keep the pressure in the entire space 15 (chamber 15) below atmospheric pressure. In particular, the inlet pressure of the resin 17 is reduced in order compensate for an increase of the pressure in the space 15 during the downward flow of the resin 17.

[0120] Step S9 may be carried out throughout the whole infusion process (e.g., in S5 to S10), whenever an adjustment of the pressure within the space 15 is necessary to keep the pressure in the space 15 below atmospheric pressure.

[0121] In step S10 of the method, a position of the resin 17 is detected by means of one or more sensors 25 at a bottom portion 26 of the lower mold 9.

[0122] In the example of FIGS. 2-4, there are shown two sensors 25 arranged within boreholes 27 in the lower mold 9. The sensors 25 are, for example, pressure sensors, but could be also other sensors capable of detecting the position of the resin 17.

[0123] In step S11 of the method, an overabundance of resin 17 in a lower portion 28 and/or in the bottom portion 26 of the lower mold 9 is handled by extracting excess resin 17″ from the lower portion 28 and/or from the bottom portion 26 (FIG. 4). The excess resin 17″ is, for example, extracted by means of a through hole 31 within the lower mold 9, a hose 32, a pump 33, and an overflow container 34.

[0124] It is noted that in FIG. 4 the resin 17 infused already into the fiber lay-up 11 is not shown for clarity.

[0125] Step 11 of the method may be carried out throughout the whole infusion process (e.g., in S8 to S10), whenever an overabundance of resin 17 occurs in a lower part of the mold 8.

[0126] In step S12 of the method, a vacuum is applied to the top inlet channels 16 in order to keep the resin 17 in an upper portion 29 and/or a top portion 30 of the upper mold 10.

[0127] Step S12 may be carried out simultaneously with any of steps S7 to S11. In particular, step 12 may be carried out at the end of the infusion process and/or after finishing the infusion process (e.g., at the end of S8, after S8, S9, S10 and/or S11).

[0128] FIG. 5 shows a variant of the at least one upper resin inlet channel 16 of FIGS. 2-4. Shown in FIG. 5 is a perspective view of the lower mold 9 and the two mold cores 14 of the mold 8. The upper mold 10 is not shown in FIG. 5 for illustration purposes. In the example of FIG. 5, the at least one upper resin inlet channel 116 comprises four upper resin inlet channels 116 arranged on the mold cores 14, parallel to each other and along a longitudinal direction L1 of the mold 8. The longitudinal direction L1 of the mold 8 defines a longitudinal direction of the blade manufactured by use of the mold 8. Resin is supplied through a hose 42 via a branch 43 and two manifolds 35 to the four upper resin inlet channels 116.

[0129] An insert I in FIG. 5 shows an extended view of the branch 43, the manifolds 35 and the upper resin inlet channels 116.

[0130] In the example of FIG. 5, there are shown one branch 43, two manifolds 35 and one hose 42. However, in another example, there may be two hoses, two branches and no manifold. In this case, each of the two hoses is connected fluidly with one of the two branches. Further, each of the two branches is fluidly connected with two of the four upper resin inlet channels.

[0131] In the example of FIG. 5, there are shown four upper resin inlet channels 116. However, in another example, there may be a different (even or uneven) number of upper resin inlet channels.

[0132] Furthermore, any suitable number of upper resin inlet channels 116, hoses 42, branches 43 and manifolds 35 can be used.

[0133] The method according to the first embodiment may be applied for manufacturing of the entire wind turbine blade 3 (FIG. 1). In this case the described upper resin inlet channels 16 (or 116) are arranged along the entire upper mold 10. Alternatively, as shown in FIG. 6, the upper mold 10 may comprise the described upper resin inlet channels 16 (or 116) only in a lengthwise section C1 of the upper mold 10 configured for manufacturing an inboard blade section of the wind turbine blade 3. The section C1 corresponds, for example, to one third of the entire length L3 of the mold 8. The fiber lay-up 11, 11′ in the mold 8 in the section C1 is, for example, infused with resin as described in steps S1 to S12. The fiber lay-up 11, 11′ in the mold 8 in the section C2 is, for example, infused with resin by providing resin only through the inlet channels 18 and 19.

[0134] In the following an improved method for manufacturing a wind turbine blade 3 according to a second embodiment is described with respect to FIGS. 8 and 9.

[0135] The mold 8′ used in the method according to the second embodiment is similar to the mold 8 used in the method according to the first embodiment apart from a different arrangement of upper resin inlet channels 37, 38 and of sensors 39, 40.

[0136] As shown in FIG. 8, the upper mold 10′ of the mold 8′ according to the second embodiment comprises in addition to or instead of upper resin inlet channels 16′ upper resin inlet channels 37 and 38. The upper resin inlet channels 37 and 38 are arranged half way between a top portion 30′ of the upper mold 10′and a lower end 41′ of the upper mold 10′. Furthermore, the upper resin inlet channels 37 and 38 are, for example, arranged between the dry fiber lay-up 11 and the vacuum bag 13.

[0137] Furthermore, the upper mold 10′ according to the second embodiment comprises the sensors 39 and 40 above the upper resin inlet channels 37 and 38, respectively.

[0138] Steps S1′, S2′ and S3′ of the method according to the second embodiment are similar as steps S1, S2, and S3 of the method according to the first embodiment. Therefore, a description thereof will be omitted.

[0139] In step S4′ of the method according to the second embodiment, a supply of resin to the at least one further resin inlet channel, i.e. in the example of FIG. 8 to the two further resin inlet channels 18′ and 19′, is started. Furthermore, resin (not shown in FIG. 8) is provided through openings of the further resin inlet channels 18′ and 19′. The resin is provided through the openings of the further resin inlet channels 18′ and 19′ with an inlet pressure below atmospheric pressure. The inlet pressure has, for example, a similar value or range as the inlet pressure of the resin 17 provided through the upper resin inlet channels 16 in the first embodiment.

[0140] In step S5′ of the method according to the second embodiment, the resin provided through the further resin inlet channels 18′ and 19′ is infused into the fiber layup 11′ due to the vacuum generated in the space 15′. In particular, the resin provided through the further resin inlet channels 18′ and 19′ is flowing upwards wetting the fiber layup 11′ in the upper mold 10′. Furthermore, the resin provided through the further resin inlet channels 18′ and 19′ is also flowing downwards wetting the fiber layup 11′ in the lower mold 9′.

[0141] In step S6′ of the method according to the second embodiment, a position of the resin provided through the further resin inlet channels 18′ and 19′ and flowing upwards is detected by means of the sensors 39 and 40.

[0142] In particular, the sensor 39 is arranged above the upper resin inlet channel 37. By means of the sensor 39 it can be detected if the resin provided through the further resin inlet channel 18′ and flowing upwards has passed the upper resin inlet channel 37. Furthermore, by means of the sensor 40 it can be detected if the resin provided through the further resin inlet channel 19′ and flowing upwards has passed the upper resin inlet channel 38.

[0143] In step S7′ of the method according to the second embodiment, resin is provided through the upper resin inlet channels 37 and 38, if it was detected by means of the sensors 39, 40 that a flow front of the resin provided through the further resin inlet channels 18′, 19′ has reached and passed the upper resin inlet channels 37 and 38, respectively.

[0144] In detail, a supply of resin to the upper resin inlet channels 37 and 38 is started in step S7′ and resin (not shown) is provided through openings of the upper resin inlet channels 37 and 38. The resin provided through the upper resin inlet channels 37, 38 is delivered with an inlet pressure below atmospheric pressure. The inlet pressure has, for example, a similar value or range as the inlet pressure of the resin 17 provided through the upper resin inlet channels 16 in the first embodiment.

[0145] In step S8′ of the method according to the second embodiment, the fiber layup 11′ in the upper mold 10′ is infused with resin provided through the further resin inlet channels 18′ and 19′ and through the upper resin inlet channels 37 and 38.

[0146] The resin provided through the upper resin inlet channels 37 and 38 supports an upward flow of resin through the fiber layup 11′ in the upper mold 10′. Thus, the fiber layup 11′ can be better wetted even in an upper portion 29′ and/or a top portion 30′ of the upper mold 10′. Therefore, spots of fiber layup 11′ remaining dry, i.e. without resin, in the manufactured blade 3 can be better prevented, even for very large blades having a large cross section.

[0147] The upper mold 10′ according to the second embodiment may comprise in addition to the upper resin inlet channels 37 and 38 also upper resin inlet channels 16′, as shown in FIG. 8. Resin provided through the optional upper resin inlet channels 16′ can further support the infusion of the fiber layup 11′ in the upper portion 29′ and in the top portion 30′ of the upper mold 10′.

[0148] The mold 8′ according to the second embodiment may also comprise further sensors in addition to the sensors 39, 40. For example, the mold 8′ may comprise sensors 25′ similar to the sensors 25 of the first embodiment.

[0149] FIG. 10 illustrates, in cross-section, a geometrical arrangement of the at least one upper inlet 16 and the at least one further inlet 18, 19 according to the first embodiment. Furthermore, FIG. 10 illustrates, in cross-section, the geometrical arrangement of the at least one upper inlet 37, 38, the optional at least one upper inlet 16′ and the at least one further inlet 18′, 19′ according to the second embodiment.

[0150] The at least one upper inlet 16 according to the first embodiment is arranged at the upper portion 29 of the upper mold 10. In the example shown in FIGS. 2-4 and 10, the at least one upper inlet 16 comprises two upper resin inlet channels 16. The upper resin inlet channels 16 are both arranged at the top portion 30 of the upper mold 10. In particular, each of the upper resin inlet channels 16 is, as seen in the cross-section view of FIGS. 2-4 and 10, arranged at a height H1 above a lower end 41 of the upper mold 10. The height H1 corresponds to an angle α1 larger than 80 degrees in the example of FIGS. 2-4 and 10. The angle α1 is, in particular, defined between a horizontal plane H and a plane A. The horizontal plane H includes the lower end 41 of the upper mold 10 and/or a dividing line between the lower and upper molds 9, 10. The plane A is, as seen in cross-section, intersecting a longitudinal axis L2 of the manufactured blade and the at least one upper inlet 16.

[0151] The at least one upper inlet 37, 38 according to the second embodiment is arranged at the upper portion 29′ of the upper mold 10′. In the example shown in FIGS. 8 and 10, the at least one upper inlet 37, 38 comprises two upper resin inlet channels 37 and 38. Each of the upper resin inlet channels 37, 38 is, as seen in the cross-section view of FIGS. 8 and 10, arranged at a height H2 above a lower end 41′ of the upper mold 10′. The height H2 corresponds to an angle α2 of about 45 degrees in the example of FIGS. 8 and 10. The angle α2 is, in particular, defined between a horizontal plane H including the lower end 41′ of the upper mold 10′ and a plane B. The plane B is, as seen in cross-section, intersecting a longitudinal axis L2 of the manufactured blade and the at least one upper inlet 37, 38.

[0152] The mold 8′ according to the second embodiment may optionally also comprise the upper resin inlet channels 16′, as shown in FIGS. 8 and 10. In the example shown in FIGS. 8 and 10, the at least one upper resin inlet 16′ comprises two upper resin inlet channels 16′ configured and arranged similar as the upper resin inlet channels 16 according to the first embodiment.

[0153] Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

[0154] For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements.