Method for removing spar cap elements

Abstract

The present disclosure relates to a method (100, 200) for removing a spar cap element (50) from a spar cap (74, 76) for a wind turbine blade (10), and to a related assembly. The method (100) comprises: heating a portion of thermoplastic material (55), the portion of thermoplastic material (55) at least 5-partially surrounding a first thermoset pultrusion element (50); removing part or all of the heated portion of the thermoplastic material; and removing at least a portion of the first thermoset pultrusion element (50).

Description

Technical Field

[0001] This application claims the benefit of European patent application No. 22 161 175.9 filed on March 9, 2022.

[0002] The present disclosure relates to a method for removing a spar cap element from a spar cap for a wind turbine blade. The present disclosure also relates to a method for repairing a spar cap for a wind turbine blade, and to related assemblies. Background Art

[0003] Modern wind turbines are commonly used to supply electricity to an electrical grid. Such wind turbines typically include a tower and a rotor arranged on the tower. The rotor typically includes a hub and a plurality of blades, arranged to rotate under the influence of wind acting on the blades. The rotation generates a torque, which is typically transmitted to a generator via a rotor shaft, either directly ("direct drive" or "gearless") or by using a gearbox. In this way, the generator generates electricity, which can be supplied to an electrical grid.

[0004] The wind turbine hub may be rotatably coupled to the front of the nacelle. The wind turbine hub may be connected to the rotor shaft, and the rotor shaft may then be rotatably mounted in the nacelle using one or more rotor shaft bearings arranged in a frame inside the nacelle. The nacelle is a housing arranged on top of the wind turbine tower that may house and protect the gearbox (if present) and the generator (if not placed outside the nacelle), and depending on the wind turbine, may also house and protect components such as the power converter and auxiliary systems.

[0005] In order to extract more energy from the wind, the size of the rotor diameter is increased by increasing the size of the wind turbine blades. The larger size of the blades introduces higher physical loads into the blades and related components. Wind turbine rotor blades typically include a body shell, which is formed by two shell halves of a composite material (e.g., a glass fiber composite). The shell halves are typically manufactured using a molding process and then coupled together along the respective edges of the rotor blade. The body shell is relatively lightweight and has the following structural characteristics: it is not designed to withstand all bending moments and other loads acting on the blade during operation. In order to improve the structural characteristics of the rotor blade, such as stiffness, strength, and buckling resistance, the body shell is typically reinforced with structural components, such as spar caps at the suction and pressure sides of the blade, with one or more shear webs connecting them. The spar caps may also be referred to as the "main laminate" or "spar cap laminate" of the wind turbine blade.

[0006] Spar caps can be manufactured using several materials, such as glass fiber laminate composites and carbon fiber laminate composites. Modern spar caps can be manufactured using pultruded composites. Composites manufactured by pultrusion can have a constant cross-section, which can be easily stacked to form larger composite parts. Thus, multiple pultruded sheets can be stacked together and infused in a mold to form a larger (i.e. longer, thicker, wider) composite part, such as a spar cap.

[0007] The spar caps may be manufactured "offline", i.e. the spar caps may be manufactured separately from the rest of the blade. A stack of pultruded sheets may be placed in a mould, which may then be impregnated with a thermosetting resin. The stack of impregnated sheets forms the spar caps, which are then joined to the shell of the wind turbine blade.

[0008] If a spar cap is damaged or defective, for example if it has cracks or delaminations, or if tolerances are not met, it is typically discarded and replaced by an entirely new spar cap. Thus, the resources invested in manufacturing the spar cap, including time and materials, are lost, and additional time, materials, and man-hours are required to manufacture a new spar cap.

[0009] Defects may occur during the off-line manufacturing process of the spar caps described above, or after the spar caps have been joined to the shell of the blade. Defects may even occur during storage, transportation or use of the manufactured wind turbine blades.

[0010] The present disclosure is directed to reducing the need to replace damaged or defective spar caps. Summary of the invention

[0011] In one aspect of the present disclosure, a method for removing one or more thermoset pultruded elements from a spar cap for a wind turbine blade is provided. The spar cap includes a plurality of thermoset pultruded elements, each of the thermoset pultruded elements being at least partially surrounded by a thermoplastic material. The method includes: heating a portion of the thermoplastic material, the portion of the thermoplastic material at least partially surrounding a first thermoset pultruded element. The method also includes: removing some or all of the heated portion of the thermoplastic material; and removing at least a portion of the first thermoset pultruded element.

[0012] According to this aspect, one or more thermoset pultruded elements (such as pultruded sheets and stacks of pultruded sheets, or one or more portions thereof) may be removed from a spar cap by heating and removing the thermoplastic material at least partially surrounding them. Thus, the desired thermoset pultruded element may be removed from the spar cap in a non-destructive manner while maintaining the structural integrity of the remainder of the spar cap. A new or identical thermoset pultruded element may then be added to the spar cap for repairing it. Throwing away a defective spar cap and starting manufacturing from scratch may be avoided. Material, labor, and time resources may be used more efficiently. A relatively quick and easy repair process may be obtained.

[0013] In the prior art, such repairs are not known, and are usually not even possible, because when manufacturing the spar caps, thermosetting resins are usually used to impregnate the stack of pultruded plates. If a defect occurs at any time during or after the resin infusion process, the spar caps usually always need to be discarded entirely.

[0014] Throughout this disclosure, the term "thermoset pultruded sheet" is generally used to define a reinforcing material, such as fibers or woven or braided wires, which is impregnated with a thermoset material (such as a thermosetting resin) and pulled through a hot female die so that the thermoset material cures or undergoes polymerization. Such pultruded sheets can be stacked to form a "stack of pultruded sheets". The pultruded sheets included in the stack of pultruded sheets can have the same or different sizes. For example, different pultruded sheets can have different lengths and / or widths. As used herein, pultruded sheets and stacks of pultruded sheets are encompassed by the term "pultrusion element".

[0015] Throughout this disclosure, thermoset materials generally include plastic materials or polymers that, once cured, cannot be easily re-molded or returned to a liquid state. Therefore, after initial molding, thermoset materials are generally resistant to heat, corrosion, and / or creep. Examples of thermoset materials generally may include, but are not limited to, some polyesters, esters, or epoxies.

[0016] Throughout this disclosure, thermoplastic materials generally include plastic materials or polymers that typically become soft or moldable when heated to a certain temperature and solidify when cooled. In addition, thermoplastic materials may include amorphous thermoplastic materials and / or semi-crystalline thermoplastic materials.

[0017] For example, some amorphous thermoplastic materials may generally include, but are not limited to, styrene, vinyl, cellulose, polyester, acrylic, polysulfone and / or imide. More specifically, exemplary amorphous thermoplastic materials may include, polystyrene, acrylonitrile-butadiene-styrene (ABS), polymethyl methacrylate (PMMA), ethanolized polyethylene terephthalate (PET-G), polycarbonate, polyvinyl acetate, amorphous polyamide, polyvinyl chloride (PVC), polyvinylidene chloride, polyurethane, or any other suitable amorphous thermoplastic material. In addition, exemplary semi-crystalline thermoplastic materials may generally include, but are not limited to, polyolefins, polyamides, fluorocopolymers, methyl acrylate, polyesters, polycarbonates, and / or acetals. More specifically, exemplary semi-crystalline thermoplastic materials may include, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polypropylene, polyphenylene sulfide, polyethylene, polyamide (nylon), polyetherketone, or any other suitable semi-crystalline thermoplastic material.

[0018] In another aspect of the present disclosure, a method for removing one or more thermoset pultruded sheets from a spar cap for a wind turbine blade is provided. The spar cap includes a plurality of thermoset pultruded sheets separated by thermoplastic material. The method includes: removing a top thermoset pultruded sheet; heating and removing the thermoplastic material surrounding the thermoset pultruded sheet below the top thermoset pultruded sheet; and removing the next thermoset pultruded sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 illustrates a perspective view of an example of a wind turbine; Figure 2A illustrates a perspective view of an example of a wind turbine blade; Figure 2B schematically illustrates the internal structure of a wind turbine blade; Figure 2C illustrates a molding system that may be used in the manufacture of wind turbine blades; Figure 3 A flow chart illustrating an example of a method for removing one or more thermoset pultruded components from a spar cap for a wind turbine blade; Figures 4A to 6B schematically illustrates examples of cross-sections of different spar caps in which the methods disclosed herein may be used; and Figure 7A flow chart illustrating an example of a method for repairing a spar cap for a wind turbine blade. DETAILED DESCRIPTION

[0020] Reference will now be made in detail to embodiments of the present disclosure, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation only and not as a limitation. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made in the present disclosure. For example, a feature illustrated or described as part of one embodiment may be used together with another embodiment to produce yet another embodiment. Therefore, the present disclosure is intended to cover such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0021] Figure 1 A conventional modern upwind wind turbine 2 according to the so-called "Danish concept" is illustrated, having a tower 4, a nacelle 6 and a rotor with a substantially horizontal rotor axis. The rotor comprises a hub 8 and three blades 10 extending radially from the hub 8, each blade having a blade root 16 closest to the hub and a blade tip 14 farthest from the hub 8.

[0022] Figure 2A A schematic view of an exemplary wind turbine blade 10 is shown. The wind turbine blade 10 has the shape of a conventional wind turbine blade, with a root end 17 and a tip end 15, and includes a root region 16 closest to the hub, a profiled or airfoil region 34 farthest from the hub, and a transition region 32 between the root region 16 and the airfoil region 34. The blade 10 includes 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 in the opposite direction of the leading edge 18.

[0023] The airfoil region 34, also referred to as the profiled region, has an ideal or nearly ideal blade shape in terms of generating lift, while the root region 16 has a generally circular or elliptical cross section due to structural considerations, which, for example, makes it easier and safer to mount the blade 10 to the hub. The diameter (or chord length) of the root region 16 can be constant along the entire root region 16. The transition region 32 has a transition profile that gradually changes from the circular or elliptical shape of the root region 16 to the airfoil profile of the airfoil region 34. The chord length of the transition region 32 typically increases with increasing distance 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 from the hub.

[0024] The shoulder 40 of the blade 10 is defined as the location where the blade 10 has its maximum chord length. The shoulder 40 is typically disposed at the boundary between the transition region 32 and the airfoil region 34.

[0025] It should be noted that the chords of different sections of the blade do not usually lie in the same plane, as the blade may be twisted and / or bent (i.e. pre-bent), thereby providing a correspondingly twisted and / or bent path for the chord plane, which is most often the case in order to compensate for the local velocity of the blade, which depends on the radius from the hub. The wind turbine blade 10 includes a blade shell, which includes two blade shell parts or half shells (a first blade shell part 24 and a second blade shell part 26), typically made of fiber reinforced polymer. The wind turbine blade 10 may include additional shell parts, such as a third shell part and / or a fourth shell part. The first blade shell part 24 is typically a pressure side or upwind blade shell part. The second blade shell part 26 is typically a suction side or downwind blade shell part. The first blade shell part 24 and the second blade shell part 26 are fastened together with an adhesive (e.g. glue) along a join line or glue joint 28, which extends along the trailing edge 20 and the leading edge 18 of the blade 10. Typically, the root end of the blade shell portions 24, 26 has a semi-circular outer cross-sectional shape.

[0026] Figure 2B is a schematic diagram illustrating a cross-sectional view of an exemplary wind turbine blade 10, such as a cross-sectional view of an airfoil region 34 of the wind turbine blade 10. The wind turbine blade 10 includes: a leading edge 18, a trailing edge 20, a pressure side 24, a suction side 26, a first spar cap 74, and a second spar cap 76. The wind turbine blade 10 includes a chord line 38 between the leading edge 18 and the trailing edge 20. The wind turbine blade 10 includes a shear web 42, such as a leading edge shear web and a trailing edge shear web. Alternatively, the shear web 42 may be a spar box with a spar side, such as a trailing edge spar side and a leading edge spar side. The spar caps 74, 76 may include carbon fiber, while the remainder of the shell portion 24, 26 may include glass fiber.

[0027] Figure 2C 1 is a schematic diagram illustrating an exemplary mold system for molding a blade shell of a wind turbine blade. The mold system 100 includes a first mold 102 and a second mold 112. The first mold 102 is configured for manufacturing a first blade shell portion of a wind turbine blade, such as an upwind shell portion of a wind turbine blade (forming a pressure side), and has a mold surface 104 for depositing fibers. The second mold 112 is configured for manufacturing a second blade shell portion of a wind turbine blade, such as a downwind shell portion of a wind turbine blade (forming a suction side), and has a mold surface 114 for depositing fibers.

[0028] In one aspect of the present disclosure, a method 100 is provided for removing one or more thermoset pultruded elements 50 from a spar cap 74, 76 for a wind turbine blade 10. The spar cap 74, 76 includes a plurality of thermoset pultruded elements 50, wherein each of the thermoset pultruded elements 50 is at least partially surrounded by a thermoplastic material 55. The method 100 includes: Figure 3 The process is schematically shown in the flow chart.

[0029] The method includes, at box 110, heating a portion of the thermoplastic material 55, the portion of the thermoplastic material 55 at least partially surrounding the first thermoset pultruded element 50. Any suitable heating tool 45 that allows selective heating can be used. For example, a torch or heater that can be moved over the spar cap can be used. In this way, certain specific areas of the thermoplastic material can be heated in a controlled manner. The method also includes, at box 120, removing some or all of the heated portion of the thermoplastic material. The method also includes, at box 130, removing at least a portion of the first thermoset pultruded element 50. In some examples, the spar caps can be arranged in a spar cap mold. In other examples, the spar caps can be supported, held and / or fixed by any suitable supporting or fixing element (such as a crane, bracket, conveyor belt and others). A lifting element such as a crane or other can be used to remove one or more thermoset pultruded elements.

[0030] Heating a portion of the thermoplastic material may include heating a top portion or a bottom portion of the spar cap 74 . Figure 4A A cross section of an example of a spar cap 74 is schematically illustrated. The spar cap 74 will extend lengthwise perpendicular to the plane of the figure. The spar cap 74 includes four thermoset pultruded elements 50, such as carbon fiber reinforced thermoset pultruded elements. In this example, the thermoset pultruded elements 50 are pultruded sheets 51, such as carbon fiber reinforced pultruded sheets. In the cross section, each of the pultruded sheets 51 is completely surrounded by a thermoplastic material 55. In this example and other examples, the thermoplastic material 55 may, for example, include a thermoplastic reinforced prepreg. Specifically, at least the top surface and the bottom surface of each pultruded sheet 51 are surrounded by the thermoplastic material 55. The heating tool 45 is used to heat the top portion of the spar cap. The thermoplastic material surrounding the top pultruded sheet 61 is heated and at least a portion thereof is removed. This allows access to the top pultruded sheet 61, which is also removed. Removal of the top pultruded sheet 61 is performed in Figure 4B The remaining spar caps retain their structural integrity.

[0031] In other examples, the spar cap may include more or less than four pultruded sheets. If desired, one or more of the remaining pultruded sheets 51 may be removed, for example, from top to bottom, in the same manner by heating and removing an appropriate amount of thermoplastic material 55. In this example and other examples, it is also possible to first remove the bottom pultruded sheet 64 and then, if desired, remove one or more additional pultruded sheets 51 from bottom to top.

[0032] Although the pultruded panels 51 are shown as thin, wide, and long panels stacked on top of each other in all depicted examples, it should be noted that this is for illustration purposes only. That is, in any of the depicted examples, a single pultruded panel 51 may actually include multiple pultruded panels or "strips" adjacent to each other. In cross section, each pultruded panel or strip may have a width of, for example, between 5 and 15 cm and a height of between 2 and 10 mm.

[0033] exist Figure 4A In the example of , it is possible to remove only a portion of the top pultruded sheet, rather than removing the entire top pultruded sheet. Figure 4C Such an example is schematically illustrated in . In this example, the top pultruded sheet 61 or a portion thereof can be exposed by heating and removing the thermoplastic material 55. A first portion 611 of the pultruded sheet, such as a damaged portion, can be separated from the pultruded sheet and removed. The location and size of the portion 611 to be separated can depend, for example, on the degree of damage to the top pultruded sheet 61. The separation can be performed by cutting, sawing or other means. The second portion 612 of the pultruded sheet can be retained as part of the spar cap 74. Removing a portion 611 of the pultruded sheet 51 is generally applicable to any pultruded sheet. For example, a portion of the bottom pultruded sheet 64 or other pultruded sheet 51 can be removed. Typically, a portion of the pultruded element 50 can be removed. For example, a portion of the pultruded stack 52 of pultruded sheets can be cut away and removed.

[0034] Figure 4D Schematically illustrated is a cross section of another example of a spar cap 74. The spar cap 74 includes two pultruded elements 50. In this example, the pultruded elements 50 are stacks 52 of pultruded sheets. Each stack 52 may include a plurality of pultruded sheets that are previously molded together using a thermosetting resin.

[0035] In cross-section, each stack 52 is completely surrounded by thermoplastic material 55. In this example, each stack 52 of pultruded sheets includes four pultruded sheets 51. Each sheet of the stack is adjacent to at least one other sheet of the stack. The thermoplastic material surrounding the top stack 71 of pultruded sheets can be heated, and at least a portion thereof can be removed. This allows access to the top stack 71 of pultruded sheets, which can be removed. In other examples, the stack 52 of pultruded sheets may include more or less than four pultruded sheets. In this example and in other examples, the spar cap 74 may include stacks 52 of pultruded sheets with the same or different numbers of sheets. All stacks 52 of the spar cap 74 may include the same number of pultruded sheets, or one or more stacks may have a different number of pultruded sheets. Figure 4A Similar to the example of , it is possible that the stack 72 of bottom pultruded sheets may be removed first.

[0036] In some examples, the method may include removing the second thermoset pultruded element 50 before heating the portion of the thermoplastic material. The second thermoset pultruded element may be removed in different ways. In some examples, see e.g. Figure 4A and Figure 5 , the second thermoset pultruded element may be a top thermoset pultruded element 61 or a bottom thermoset pultruded element 64, and the first thermoset element may be below or above the second thermoset pultruded element 61, 64, respectively, for example, immediately below or above the second thermoset pultruded element 61, 64.

[0037] Figure 5 A cross section of another example of a spar cap 74 is schematically illustrated. The spar cap 74 comprises four pultruded elements. In this example, the pultruded elements are pultruded sheets 51. The top and bottom surfaces of the intermediate pultruded sheets 62, 63, i.e. the pultruded sheets between the top pultruded sheet 61 and the bottom pultruded sheet 64, are surrounded by the thermoplastic material 55. In this example, the top surface of the top pultruded sheet 61 and the bottom surface of the bottom pultruded sheet 64 are not surrounded by the thermoplastic material 55.

[0038] exist Figure 5 In the example of , the removal of the second thermoset pultruded element 61 can be performed by scarfing. In this context, scarfing can be understood as a grinding process in which the thermoset element 50 can be thinned and eventually broken down. Suitable tools for scraping can include, for example, grinding wheels, grinding wheels, and sandpaper. Thus, the top pultruded sheet 61 can be scraped, for example, ground, and the next pultruded sheet 62 is removed after heating and removing at least a portion of the thermoplastic material 55 surrounding the sheet 62. In other examples, Figure 5 The pultruded sheet can be a stack of pultruded sheets. In other examples, the external thermosetting pultruded element (such as Figure 5In some of these examples, the thermoplastic material 55 may be both scraped and heated to remove the outer thermoset pultruded element.

[0039] Since the outer thermoset pultruded elements 61, 64 are more accessible than the intermediate thermoset pultruded elements 62, 63, the use of the thermoplastic material 55 to cover the top and bottom surfaces of the intermediate thermoset pultruded elements 62, 63 can facilitate faster and easier removal thereof. Also the use of the thermoplastic material 55 to cover the top and bottom surfaces of the outer pultruded elements 61, 64 can further facilitate simplifying and speeding up the process of separating one or more outer thermoset pultruded elements 61, 64 from the spar caps 74, 76, as processes such as grinding can be avoided.

[0040] In a similar manner to the first thermoset pultruded element, the second thermoset pultruded element may also be removed. Figure 4A In the example of , the first and second thermoset pultruded elements can be, for example, any two pultruded sheets 51 adjacent to each other. That is, the first thermoset pultruded element can be above or below the second thermoset pultruded element. The second thermoset pultruded element can be, for example, the top pultruded sheet 61, and the first thermoset pultruded element can be, for example, the upper middle pultruded sheet 62. Therefore, removing the second pultruded element can include: heating a portion of the thermoplastic material, the portion of the thermoplastic material at least partially surrounding the second thermoset pultruded element, and removing part or all of the heated portion of the thermoplastic material 55.

[0041] In some examples, the plurality of thermoset elements 50 can be arranged in two or more columns. In some of these examples, a first thermoset element can be removed from a first column and a second thermoset element can be removed from the same first column. Fig. 6A Another example of a cross section of a spar cap 74 is schematically illustrated, the spar cap 74 comprising a plurality of pultruded sheets 51. In this example, the pultruded sheets are arranged in two columns 66, 67 and in a plurality of rows (in Fig. 6A ). The first thermoset element may be, for example, the pultruded sheet of the second row (starting from the top) and left column 66, and the second thermoset element may be, for example, the top pultruded sheet of the left column 66.

[0042] In other examples, a first thermoset pultruded element may be removed from a first column and a second thermoset pultruded element may be removed from a second, different column. Fig. 6A , the first thermoset pultruded element may be, for example, the top pultruded sheet of the left column 66 , and the second thermoset pultruded element may be, for example, the top pultruded sheet of the right column 67 .

[0043] In general, the first and second thermoset pultruded elements may be any two thermoset pultruded elements of the spar cap to be removed. They may be adjacent to each other, such as vertically or laterally adjacent to each other, or there may be one or more other thermoset pultruded elements between them.

[0044] Figure 6B Another example of a cross section of a spar cap 74 is schematically illustrated. In this example, the thermoset pultruded element 50 is a stack 52 of pultruded sheets. The spar cap 74 comprises two rows 86, 87 and three columns 66, 67, 68 of the stack 52 of pultruded sheets.

[0045] In examples where the plurality of thermoset pultruded elements 50 are arranged in two or more rows, for example, Fig. 6A and 6B In the first column (for example Fig. 6A The columns 66 in the middle may be removed in a single operation. This may mean removing a certain column (e.g., an outer column) at one time, rather than removing the thermoset pultruded elements 50 of that column at different times. For example, in Figure 6B In the example of , the left column 66 may be completely removed before starting to remove the stack 52 from the other columns. In some examples, the removal of the thermoset pultruded elements may be performed on a column-by-column basis. This may speed up the removal process. If the first and second thermoset pultruded elements are in the same column, the column may be removed in a single operation. If the first and second thermoset pultruded elements are in different columns, each of the columns may be removed in a single operation, or if the columns are adjacent, the two columns may be removed simultaneously in a single operation.

[0046] In examples where the plurality of thermoset pultruded elements 50 are arranged in two or more rows, for example Figures 4A-6B In , one or more rows can be removed in a single operation. For example, in Fig. 6A In the example of , the top row may be completely removed before starting to remove the pultruded sheets 51 from other rows to remove another row. The first and second thermoset pultruded elements 50 may be in the same row or in different rows. The row including the first thermoset pultruded element may be removed in a single operation, and the row including the second thermoset pultruded element may be removed in a single operation. If two rows are adjacent, the two rows may be removed together in a single operation. Removal of the thermoset pultruded elements may be performed row by row on the thermoset pultruded elements. Depending on the configuration of the thermoset pultruded elements (e.g., the number and arrangement), row-by-row or column-by-column removal may be appropriate. In other examples, different strategies for removing thermoset pultruded elements may be used.

[0047] In some examples, the method may further include: adding one or more thermoset pultruded elements 50 and / or portions of one or more thermoset pultruded elements to the spar caps 74, 76 and joining them to the spar caps by using a thermoplastic material. If a portion of a thermoset pultruded element is added, it may be further joined to a corresponding portion of the thermoset pultruded element of the spar cap, for example, by gluing or in any suitable manner. In this way, after removing one or more thermoset pultruded elements 50 or portions thereof, the same and / or new thermoset pultruded elements may be added and joined to the spar caps for manufacturing spar caps with desired specifications and characteristics. If a thermoset pultruded element or a portion thereof is damaged, it may be replaced. If there are undamaged thermoset pultruded elements, but they need to be removed, for example, to access the damaged thermoset pultruded elements or to adjust their position, the same thermoset pultruded elements may be used. In this way, at least a portion of the existing spar caps may still be used, and less material and time may be wasted than if a new spar cap needs to be built.

[0048] Depending on the type of spar cap, this step may be performed in different ways. For example, the thermoset pultruded element 50 and the thermoplastic material 55 may be added to the spar cap mold and cured. In other examples, the thermoset pultruded element may be at least partially surrounded by a thermoplastic material to form a block, and it may be joined to another block via thermoplastic welding. It may be possible to add and join the thermoset pultruded element and the thermoplastic material to the spar cap using other means.

[0049] The method 100 may be used while the spar caps 74, 76 are being manufactured, for example, if a defect or problem has been detected before the spar caps are completed or after their manufacture (e.g., once the spar caps have been removed from their molds, after the defect in question has been detected). The method 100 may also be used after the spar caps have been assembled with the shell of a wind turbine blade, for example, after a wind turbine blade 10 of a wind turbine has been damaged. One or more spar caps of the damaged wind turbine blade may be recycled and refurbished as explained herein for use in a wind turbine blade. The method may also include removing a portion of the shell of the wind turbine blade.

[0050] In some examples, the method may also include determining that the spar caps 74, 76 include one or more defects before initiating removal of the one or more thermoset pultruded elements 50 from the spar caps. Determining the presence of one or more defects may include detecting cracks, delamination, erosion, deformation, improper positioning of the one or more thermoset pultruded elements, or others. The determination may occur at one or more of a manufacturing site, a wind farm site, and during transportation.

[0051] Therefore, despite the Figures 4A-6BIn the examples illustrated in , the spar caps have been shown as separate units, i.e. not attached to other wind turbine blade components (e.g., the shell of the wind turbine blade), but it should be clear that similar methods can be used at a later stage. For example, if a defect occurs or is detected after the spar caps have been joined to the shell of the wind turbine blade, in the prior art, the entire assembly would typically be discarded. However, using examples of the methods and systems disclosed herein, portions of the spar caps or blade assemblies may be salvaged. Defects may even occur or be noticed after storage or during transportation. In some examples, repair may require removal of a portion of the blade shell or replacement of a portion of the blade shell.

[0052] In another aspect of the present disclosure, a method 200 is provided for removing one or more thermoset pultruded sheets 51 from a spar cap 74, 76 for a wind turbine blade 10. The spar cap includes a plurality of thermoset pultruded sheets 51 separated by thermoplastic material 55. The method 200 includes: Figure 7 For example, the method can be applied to Figure 4A , 4B , 5 and 6A. The description and explanation of the spar caps 74, 76 and the pultruded plate 51 related to the method 100 also apply to the method 200, and vice versa.

[0053] The method includes: at block 210, removing the top thermoset pultruded sheet. In some examples, the top thermoset pultruded sheet can be removed by grinding. If the top pultruded sheet is surrounded by thermoplastic material 55, the top thermoset pultruded sheet can be removed by heating and removing the thermoplastic material 55 surrounding the top thermoset pultruded sheet.

[0054] The method further includes heating and removing the thermoplastic material surrounding the thermoset pultruded sheet below the top thermoset pultruded sheet at block 220. The method further includes removing the next thermoset pultruded sheet, ie, the sheet below the top thermoset pultruded sheet, at block 230.

[0055] Once the necessary thermoset pultruded sheet has been removed, the necessary thermoset pultruded sheet (eg, new thermoset pultruded sheet) may be added to the spar cap. The method may also include completing the spar cap by joining the missing thermoset pultruded sheet to the spar cap using a thermoplastic material 55 .

[0056] The spar caps 74, 76 may be repaired after defects in the spar caps have been detected during their manufacture.

[0057] This written description uses examples to disclose teachings, including preferred embodiments, and also enables any person skilled in the art to put the teachings into practice, including making and using any device or system, and performing any incorporated method. The patentable scope is defined by the claims and may include other examples that occur to a person skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that are not different from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims. In accordance with the principles of the present application, aspects from the various embodiments described and other known equivalents for each such aspect may be mixed and matched by one of ordinary skill in the art to construct additional embodiments and techniques. If reference numerals associated with the drawings are placed in parentheses in the claims, they are merely an attempt to increase the understandability of the claims and should not be interpreted as limiting the scope of the claims.

Claims

1. A method (100) for removing one or more thermoset pultruded components (50) from a spar cap (74, 76) for a wind turbine blade (10), the spar cap (74, 76) comprising a plurality of thermoset pultruded components (50), wherein each of the thermoset pultruded components is at least partially surrounded by a thermoplastic material (55), the method comprising: heating (110) a portion of a thermoplastic material (55) at least partially surrounding the first thermoset pultruded element (50); removing (120) some or all of the heated portion of the thermoplastic material (55); as well as At least a portion of the first thermoset pultruded element (50) is removed (130).

2. The method according to claim 1, wherein: Heating (110) the portion of the thermoplastic material (55) includes heating a top portion or a bottom portion of the spar cap (74, 76).

3. The method according to claim 1 or 2, further comprising: Prior to heating (110) the portion of the thermoplastic material (55), the second thermoset pultruded element (50) is removed.

4. The method according to claim 3, wherein: Removal of the second thermosetting pultruded element (50) is performed by scraping.

5. The method according to claim 3 or 4, wherein: The second thermoset pultruded component (50) is a top thermoset pultruded component (61, 71) or a bottom thermoset pultruded component (64, 74), and the first thermoset component is below or above the second thermoset pultruded component, respectively.

6. The method according to any one of claims 3 to 5, wherein: Removing the second pultruded element includes heating a portion of a thermoplastic material (55) that at least partially surrounds the second thermoset pultruded element, and removing some or all of the heated portion of the thermoplastic material (55).

7. The method according to any one of claims 1 to 6, wherein: The thermoplastic material (55) comprises a thermoplastic reinforced prepreg.

8. The method according to any one of claims 1 to 7, wherein: The thermosetting pultruded component (50) is a carbon fiber reinforced thermosetting pultruded component.

9. The method according to any one of claims 1 to 8, wherein: The spar caps (74, 76) are assembled with the shell of a wind turbine blade (10).

10. The method according to claim 9, further comprising: At least a portion of the housing is removed.

11. The method according to any one of claims 1 to 10, wherein: The plurality of thermoset pultruded elements (50) are arranged in two or more rows (66, 67, 68) and the first row is removed in a single operation.

12. The method according to any one of claims 1 to 11, further comprising: One or more thermoset pultruded elements (50) and / or portions of one or more thermoset pultruded elements are added to the spar caps (74, 76) and joined to the spar caps (74, 76) using a thermoplastic material (55).

13. The method according to any one of claims 1 to 12, wherein: The plurality of thermosetting pultruded elements (50) are a plurality of thermosetting pultruded sheets (51) or a stack (52) of a plurality of thermosetting pultruded sheets.

14. The method according to any one of claims 1 to 13, further comprising: It is determined that the spar caps (74, 76) include one or more defects.

15. The method according to claim 14, wherein: The determination occurs at one or more of a manufacturing site, a wind farm site, and during transportation.

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