Patent Application
20170028587
The present subject matter relates generally to pultruded products and, more particularly, to a system and method for in-line processing of pre-formed pultruded products for use within a wind turbine rotor blade.
Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy from wind using known foil principles and transmit the kinetic energy through rotational energy to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
Wind turbine rotor blades typically include an outer body skin or shell formed from a composite laminate material. In general, the body shell is relatively lightweight and has structural properties (e.g., stiffness, buckling resistance and strength) which are not configured to withstand the bending moments and other loads exerted on the rotor blade during operation. In addition, wind turbine blades are becoming increasingly longer in order to produce more power. As a result, the blades must be stiffer and thus heavier so as to mitigate loads on the rotor.
To increase the stiffness, buckling resistance and strength of the rotor blade, the body shell is typically reinforced using one or more structural components (e.g. opposing spar caps with a shear web configured therebetween) that engage the inner surfaces of the shell. The spar caps are typically constructed from laminate composites (e.g., glass fiber laminate composites and/or carbon fiber laminate composites) that include dry or non-cured fabric plies that are laid up within the blade mold and subsequently infused with resin. Such materials, however, can be difficult to control during the manufacturing process and/or are often defect prone and/or highly labor intensive due to handling of the non-cured fabrics and the challenges of infusing large laminated structures.
As such, recent attempts have been made to form spar caps from pre-fabricated, pre-cured laminate composites that can be produced in thicker sections, and are typically less susceptible to defects. For example, it has recently been attempted to use pultruded plates to form wind turbine spar caps. In doing so, the pultruded plates are typically formed using a conventional pultrusion process.
For instance,
To allow a pultruded product formed using the above-described process to be further processed and/or used to manufacture a wind turbine blade component, the peel ply must be initially removed from the underlying fiber-reinforced polymer product. Typically, the removal process is both labor- and time-intensive, with each peel ply being required to be manually pulled off of the underlying product. As a result, the use of peel plies to provide a desired surface finish significantly increases the overall costs associated with manufacturing finished pultruded plates.
Moreover, the heated die used during the pultrusion process is typically only capable of forming a pultruded product having a given thickness and width. Thus, to produce a pultruded product having a different thickness and/or width, a separate die must be used that has suitable dimensions designed to produce a product having the desired thickness and width. The use of such separate dies significantly increases the overall manufacturing costs associated with producing pultruded products having differing dimensions.
Accordingly, a system and method for in-line processing of pre-formed pultruded products that addresses one or more of the problems identified above in the prior art would be welcomed in the technology.
Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
In one aspect, the present subject matter is directed to a method for in-line processing of pre-formed pultruded products. The method may generally include transporting a pre-formed pultruded product in a processing direction along a travel path, wherein the product includes a combination of fibers and resin and wherein the product extends lengthwise in the processing direction and defines an initial width in a widthwise direction. The method may also include roughening an outer surface of the pre-formed pultruded product as the product is being transported in the processing direction along the travel path and cutting the pre-formed pultruded product lengthwise in the processing direction to form first and second pultruded plates as the product is being transported in the processing direction along the travel path, wherein each of the first and second pultruded plates defines a width in the widthwise direction that is less than the initial width of the product.
In another aspect, the present subject matter is directed to a method for in-line processing of pre-formed pultruded products. The method may generally include transporting a pre-formed pultruded product in a processing direction along a travel path, wherein the product includes a combination of fibers and resin and wherein the product extends lengthwise in the processing direction and widthwise in a widthwise direction. The method may also include roughening an outer surface of the pre-formed pultruded product as the pre-formed pultruded product is being transported in the processing direction along the travel path.
In a further aspect, the present subject matter is directed to a method for in-line processing of pre-formed pultruded products. The method may generally include transporting a pre-formed pultruded product in a processing direction along a travel path, wherein the product includes a combination of fibers and resin and wherein the product extends lengthwise in the processing direction and defines an initial width in a widthwise direction. The method may also include cutting the pre-formed pultruded product lengthwise in the processing direction to form first and second pultruded plates as the product is being transported in the processing direction along the travel path, wherein each of the first and second pultruded plates defines a width in the widthwise direction that is less than the initial width of the product.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:
Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
In general, the present subject matter is directed to a system and method for in-line processing of pre-formed pultruded products to be used within a wind turbine rotor blade. Specifically, in several embodiments, the disclosed system and method adds one or more in-line processing stations or steps that allow a pre-formed pultruded product to be prepared, machined and/or otherwise processed for subsequent use within a rotor blade as a finished pultruded plate. For example, in one embodiment, the system may include a plurality of in-line processing stations positioned immediately downstream of a dispenser spool from which a pre-formed pultruded product is being dispensed, such as a surface preparation station, one or more widthwise machining stations and/or a lengthwise machining station. A different machining technique and/or process may be used at each in-line processing station to prepare the pre-formed pultruded product for use within a rotor blade.
For example, the in-line surface preparation station disclosed herein may be utilized to roughen the outer surface of the pre-formed pultrusion product (e.g., using mechanical or chemical abrasion). Specifically, the surface preparation station can be used to roughen the outer surface of the pre-formed pultrusion product to a desired surface roughness for creating a sufficient bonding interface between subsequently assembled pultruded plates. Thus, such in-line surface roughening may be used as an alternative to conventional peel plies, thereby eliminating the time-intensive, manual peel ply removal process and reducing overall manufacturing costs.
Similarly, the in-line widthwise machining station(s) disclosed herein may be configured to cut and/or chamfer the pre-formed pultruded product along its widthwise direction. For instance, the widthwise machining station(s) may be configured to chamfer the pre-formed pultruded product such that the product defines a tapered thickness that narrows or reduces in the direction of the anticipated widthwise cut location for the product. In addition, the widthwise machining station(s) may also be configured to cut the pre-formed pultruded product across its width at the anticipated cut location to create a pultruded plate having a desired length.
Additionally, the in-line lengthwise cutting station disclosed herein may be configured to cut the pre-formed pultruded product (or the previously cut pultruded plate when the cutting station is positioned downstream of the widthwise matching station) along its lengthwise direction. As such, a pre-formed pultruded product (or pultruded plate) having an initial width may be cut into two or more plates defining widths that are less than the initial width. For instance, in one embodiment, a pultruded plate having an initial width may be cut down the center along its lengthwise direction to create two separate plates, with each plate defining a width that is equal to one-half of the initial width.
Referring now to
It should be appreciated that, although the various stations 106, 108, 110, 112 will generally be described herein with respect to the differing processing steps implemented by each station, such stations 106, 108, 110, 112 may form part of a single piece of equipment. For example, as shown in the dashed lines in
As shown in
As shown in
In the illustrated embodiment, the pre-formed pultruded product 104 unwound from the dispenser spool 102 is directed in the processing direction 122 into the surface preparation station 106. In general, the surface preparation station 106 may correspond to and/or include any suitable component(s), equipment and/or the like that allows an outer surface(s) 105 of the pre-formed pultruded product 104 to be roughened or knurled. As is generally understood, such a roughened or knurled outer surface provides a suitable interface for bonding or joining two separate pultruded plates to one another. Thus, the surface roughening provided by the surface preparation station 104 may allow two or more pultruded plates 114 created using the disclosed system 100 to be bonded or joined together to form a wind turbine rotor blade component. For example, the pultruded plates 114 may be stacked one on top of the other to form a spar cap of a rotor blade, with the stacked plates 114 being subsequently infused with resin to join the plates 114 together. In such instance, the roughened outer surfaces of the pultruded plates 114 may provide enhanced bonding strength between the adjacent, infused plates 114.
In several embodiments, the surface preparation station 106 may be configured to roughen the outer surface(s) 105 of the pre-formed pultruded product 104 via mechanical abrasion. For instance, in a particular embodiment, the surface preparation station 106 may include or correspond to an abrasive blasting chamber that utilizes a blasting media to roughen the outer surface(s) 105 of the pre-formed pultruded product 104 as it is transported through the chamber in the processing direction 122. Suitable blasting media may include sand, beads (e.g., glass beads), carbide particles and/or any other suitable blasting material. Alternatively, the surface preparation station 106 may include or incorporate a rotary abrasion device configured to rotationally contact the outer surface(s) 105 of the pre-formed pultruded product 104 as it is transported in the processing direction 122, thereby allowing the rotary abrasion device to roughen the outer surface(s) 105. For instance, the rotary abrasion device may correspond to a grinding disc, bristled rotary tool (e.g., a rotary wheel including high-carbon steel wire bristles attached thereto) or any other suitable rotary abrasion device.
In other embodiments, the surface preparation station 106 may be configured to roughen the outer surface(s) 105 of the pre-formed pultruded product 104 using a chemical abrasion process. For example, the surface preparation station may include or correspond to a chamber within which a suitable chemical(s) may be applied to the outer surface(s) 105 to the pre-formed pultruded product 104 such that a chemical reaction occurs that corrodes or roughens the outer surface(s) 105 as desired.
It should be appreciated that the desired surface roughness for the pultruded plates 114 formed in accordance with aspects of the present subject matter may generally vary depending on the specific application within which the plates are being utilized.
As shown in
Additionally, as indicated above, the disclosed system 100 also includes a widthwise chamfering station 108 (e.g., location downstream of the surface preparation station 106). In general, the widthwise chamfering station 108 may be configured to chamfer the pre-formed pultruded product 104 across its width at anticipated cut locations defined along its length such that the pre-formed pultruded product 104 defines a tapered thickness along either side of such anticipated cut locations. As a result, when the pre-formed pultruded product 104 is subsequently cut along its width, the resulting “cut” plates may include lengthwise ends having tapered profiles.
In general, the widthwise chamfering station 108 may include or incorporate any suitable component(s) that allows the pre-formed pultruded product 104 to be chamfered or otherwise machined as described herein. For instance, in one embodiment, the widthwise chamfering station 108 may utilize a linearly actuated grinding disc or wheel 130 to chamfer the pre-formed pultruded product 104 as it is moved relative to the grinding wheel 130 in the processing direction 122 along its travel path. An example of such an embodiment is illustrated schematically in
It should be appreciated that the anticipated cut location 134 may generally correspond to the location at which the pre-formed pultruded product 104 is desired to be cut across its width so as to create a pultruded plate have a given length (e.g., a length measured in the processing direction 122). For instance, if the pultruded plate(s) 114 being manufactured using the disclosed system 100 will be used to form a spar cap for a wind turbine rotor blade, the cut location 134 may be selected so as to create a pultruded plate(s) 114 having a suitable spanwise length for forming the spar cap.
Referring back to
It should be appreciated that, in general, the widthwise cutting station 110 may include and/or correspond to any suitable component(s), equipment and/or the like that is configured to cut the pre-formed pultruded product 104 across its width. For instance, widthwise cutting station 110 may include or correspond to a cutting wheel, a press-cutting device and/or any other suitable cutting means.
It should also be appreciated that, in certain embodiments of the present subject matter, the widthwise chamfering station 108 may also serve as the widthwise cutting station 110. For instance, in the embodiment shown in
Referring still to
For example,
In other embodiments, the cutting device 150 may be offset from the center of the pre-formed pultruded product 104 such that two separate pultruded plates are created that define differing widths (with the sum of such differing widths being substantially equal to the initial width 160 of the product 104). Alternatively, two or more cutting devices 150 may be located at different widthwise locations relative to the pre-formed pultruded product 104 such that three or more separate pultruded plates are created as the pre-formed pultruded product 104 is cut lengthwise via the cutting devices 150.
As indicated above, the roughened, chamfered and cut pultruded plates 114 creating using the disclosed system 100 may then be utilized to form a wind turbine rotor blade component. For instance, in several embodiments, an assembly of the pultruded plates 114 may be used to form a spar cap for a wind turbine rotor blade that extends along the span of the rotor blade between the blade root and the blade tip.
It should be appreciated that, as opposed to being separated from the process used to initially manufacture the pre-formed pultruded product 104, the disclosed system 100 may also be provided in-line with such initial manufacturing processes to form a continuous in-line manufacturing process that starts with the initial fibers used to form the product 104 and ends with the roughened, chamfered and cut pultruded plates 114. For instance,
It should also be appreciated that, as indicated above, the pre-formed pultruded product 104 described herein may generally include a combination of fibers and resin. For instance,
Additionally, it should be appreciated that the resin 172 described herein may generally correspond to any suitable resin material, including a thermoplastic material and/or a thermoset material. As used herein, thermoplastic materials generally encompass a plastic material or polymer that is reversible in nature. For example, thermoplastic materials typically become pliable or moldable when heated to a certain temperature and solidify upon cooling. Further, thermoplastic materials may include amorphous thermoplastic materials and/or semi-crystalline thermoplastic materials. For example, some amorphous thermoplastic materials may generally include, but are not limited to styrenes, vinyls, cellulosics, polyesters, acrylics, polysulphones, and/or imides. More specifically, example amorphous thermoplastic materials may include polystyrene, acrylonitrile butadiene styrene (ABS), polymethyl methacrylate (PMMA), glycolised polyethylene terephthalate (PET-G), polycarbonate, polyvinyl acetate, amorphous polyamide, polyvinyl chlorides (PVC), polyvinylidene chloride, polyurethane, or similar. In addition, example semi-crystalline thermoplastic materials may generally include, but are not limited to polyolefins, polyamides, fluropolymer, ethyl-methyl acrylate, polyesters, polycarbonates, and/or acetals. More specifically, example semi-crystalline thermoplastic materials may include polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polypropylene, polyphenyl sulfide, polyethylene, polyamide (nylon), polyetherketone, or similar. Further, as used herein, thermoset materials generally encompass a plastic material or polymer that is non-reversible in nature. For example, thermoset materials, once cured, cannot be easily remolded or returned to a liquid state. As such, after initial forming, thermoset materials are generally resistant to heat, corrosion, and/or creep. Example thermoset materials may generally include, but are not limited to, some polyesters, esters, epoxies, or similar.
As indicated above, the present subject matter is also directed to various methods for in-line processing of pre-formed pultruded products. For example,
As shown in
Additionally, at (204), the method 200 includes roughening an outer surface of the pre-formed pultruded product as the product is being transported in the processing direction. For example, as indicated above, a surface preparation station 106 may be provided for roughening the outer surface(s) 105 of the pre-formed pultruded product 104 via mechanical abrasion, such as by using a blasting media within an abrasion blasting chamber to roughen the outer surface(s) 105 or by using a rotary abrasion device. Alternatively, the outer surface(s) 105 of the pre-formed pultruded product 104 may be roughened using a chemical abrasion process.
Moreover, at (206), the method 200 includes machining the pre-formed pultruded product along its widthwise direction as the product is being transported in the processing direction to create a tapered thickness at an anticipated cut location for the pre-formed pultruded product. For example, as indicated above, a grinding wheel 130 or other suitable chamfering device may be utilize to grind or machine the pre-formed pultruded product 104 along its widthwise direction 162 at the anticipated cut location 134 such that the pre-formed pultruded product 104 defines a tapered thickness both upstream and downstream of the anticipated cut location 134.
Referring still to
Additionally, at (210), the method 200 includes cutting the pre-formed pultruded product lengthwise in the processing direction to form first and second pultruded plates as the product is being transported in the processing direction. For instance, as indicated above, one or more cutting device(s) 150 may be positioned along the travel path of the pre-formed pultruded product 104 that are configured to cut the product 104 lengthwise along the processing direction 122, thereby creating two or more separate pultruded plates 114A, 114B having widths 164 that are less than the initial width 160 of the pre-formed pultruded product 104.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
