Patent Description:
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, a generator, a gearbox, a nacelle, and one or more rotor blades. The rotor blades capture kinetic energy of wind using known foil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as 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.

The wind turbine tower is generally constructed of steel tubes, prefabricated concrete sections, or combinations thereof. Further, the tubes and/or concrete sections are typically formed off-site, shipped on-site, and then arranged together to erect the tower. For example, one manufacturing method includes forming pre-cast concrete rings, shipping the rings to the site, arranging the rings atop one another, and then securing the rings together. As wind turbines continue to grow in size, however, conventional manufacturing methods are limited by transportation regulations that prohibit shipping of tower sections having a diameter greater than about <NUM> to <NUM> meters. Thus, certain tower manufacturing methods include forming a plurality of arc segments and securing the segments together on site to form the diameter of the tower, e.g. via bolting. Such methods, however, require extensive labor and can be time-consuming. Document <CIT> relates to automated construction including robotic systems. Document <CIT> relates to an apparatus and a method for constructing a construction element or a building. Document <CIT> relates to products and the apparatus for their manufacture and transportation.

In view of the foregoing, the art is continually seeking improved methods for manufacturing wind turbine towers. Accordingly, the present disclosure is directed to methods for manufacturing wind turbine tower structures that address the aforementioned issues. In particular, the present disclosure is directed to methods for manufacturing wind turbine tower structures with embedded reinforcement elements.

In one aspect, the present disclosure is directed to a system for manufacturing a structure, according to claim <NUM>, such as a tower structure of a wind turbine. The system includes a supporting frame assembly moveable in a vertical direction of the structure. Further, the system includes an additive printing assembly secured to the supporting frame assembly. The additive printing assembly includes at least one printer head configured to dispense a first cementitious material. The system also includes a reinforcement dispensing assembly supported by the supporting frame assembly. Thus, the reinforcement dispensing assembly is configured to automatically and continuously dispense a plurality of reinforcing members as the structure is printed and built up via the at least one printer head and as the supporting frame assembly moves in the vertical direction.

In an embodiment, the printer head(s) of the additive printing assembly may include, at least, an outer printer head for printing an outer wall of the structure and an inner printer header for printing an inner wall of the structure. Further, in another embodiment, the additive printing assembly may include an intermediate printer head secured between the outer and inner printer heads for filling an area between the outer and inner tower walls with a second cementitious material.

In certain embodiments, the second cementitious material may be different than the first cementitious material. In particular, in one embodiment, the second cementitious material may be a self-compacting cementitious material.

As set out in claim <NUM>, the supporting frame assembly comprises at least one ring-shaped platform assembly supported by a plurality of rod members.

As set out in claim <NUM>, the ring-shaped platform assembly comprises a platform supporting an outer ring support member and an inner ring support member arranged concentrically with each other with the plurality of rod members extending therebetween. In particular embodiments, the outer and inner ring support members may each have an adjustable diameter.

In additional embodiments, the system may include a lifting jack that is moveable along each of the plurality of rod members so as to move the supporting frame assembly in the vertical direction by raising the outer and inner ring support members. In certain embodiments, the lifting jacks may be hydraulically-driven, pneumatically-driven, or mechanically-driven, such as via a screw, and/or combinations thereof.

In another embodiment, the reinforcement dispensing assembly may also include a plurality of roller devices and the plurality of reinforcing members may be reinforcing cables. In such embodiments, the reinforcing cables may be dispensed from the plurality of roller devices by automatically and continuously rolling the reinforcing cables therefrom under tension. Further, in an embodiment, the roller devices may be arranged atop the outer ring support member or the inner ring support member.

Alternatively, the reinforcement dispensing assembly may include a plurality of pulley blocks with one of the plurality of pulley blocks being arranged with each of the plurality of roller devices, the plurality of pulley blocks arranged atop the at least one ring-shaped platform assembly, the plurality of roller devices being arranged lower than the plurality of pulley blocks.

In yet another embodiment, the reinforcement dispensing assembly may include a plurality of feeder devices arranged atop at least one of the outer ring support member or the inner ring support member. In such embodiments, the reinforcing members may be reinforcing bars. Accordingly, the reinforcing bars may be dispensed from the plurality of feeder devices by automatically and continuously pushing the reinforcing bars therefrom.

In another aspect, the present disclosure is directed to a method for manufacturing a structure according to claim <NUM>. The method includes (a) providing a supporting frame assembly having at least one ring-shaped platform assembly supported by a plurality of rod members. Further, the method includes (b) arranging an additive printing assembly and a reinforcement dispensing assembly with the at least one ring-shaped platform assembly. Moreover, the method includes (c) raising the at least one ring-shaped platform assembly a certain distance in a vertical direction by moving the at least one ring-shaped platform assembly along the plurality of rod members. In addition, the method includes (d) dispensing a plurality of reinforcing members from the reinforcement dispensing assembly under tension. The method also includes (e) printing, via at least one printer head of the additive printing assembly, at least a portion of the structure via at least one cementitious material so as to embed the dispensed plurality of reinforcing members therein. As set out in claim <NUM>, the at least one ring-shaped platform assembly comprises a platform supporting an outer ring support member and an inner ring support member arranged concentrically with each other with the plurality of rod members extending therebetween.

In an embodiment, the method may include repeating steps (c) through (d) to complete the structure.

In another embodiment, moving the at least one ring-shaped platform assembly along the plurality of rod members in the vertical direction may include hydraulically driving the at least one ring-shaped platform assembly along the plurality of rod members via a plurality of lifting jacks.

In further embodiments, printing, via the at least one printer head of the additive printing assembly, at least the portion of the structure via the at least one cementitious material may include printing, via outer and inner printer heads of the additive printing assembly, outer and inner walls of the structure of a first cementitious material and filling, via an intermediate printer head secured between the outer and inner printer heads, an area between the outer and inner walls of the structure with a second cementitious material. It should be understood that the method may further include any of the additional features and/or steps as described herein.

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 of the invention as set out in the appended claims.

Generally, the present disclosure is directed to systems and methods for manufacturing structures, such as tower structures, using automated deposition of cementitious materials via technologies such as additive manufacturing, <NUM>-D Printing, spray deposition, extrusion additive manufacturing, concrete printing, automated fiber deposition, as well as other techniques that utilize computer numeric control and multiple degrees of freedom to deposit material. More specifically, the systems and methods of the present disclosure include an automated reinforcement integration module to gradually feed reinforcing members into the tower structure during the construction process, which allows for incorporation of continuous vertical reinforcing members into the completed concrete structure.

Thus, the methods described herein provide many advantages not present in the prior art. For example, the systems and methods of the present disclosure allow for automation of integrating both vertical and horizontal reinforcing members into a tower structure during construction, enable full automation of concrete structure construction, simplify the construction process with faster speeds, accommodates both steel cable and conventional steel rebar as reinforcement, and directly forms the conduits for post-tension bars or cables, which are necessary for concrete towers.

Referring now to the drawings, <FIG> illustrates one embodiment of a wind turbine <NUM> according to the present disclosure. As shown, the wind turbine <NUM> includes a tower <NUM> extending from a foundation <NUM> or support surface with a nacelle <NUM> mounted atop the tower <NUM>. A plurality of rotor blades <NUM> are mounted to a rotor hub <NUM>, which is in turn connected to a main flange that turns a main rotor shaft. The wind turbine power generation and control components are housed within the nacelle <NUM>. The view of <FIG> is provided for illustrative purposes only to place the present invention in an exemplary field of use. It should be appreciated that the invention is not limited to any particular type of wind turbine configuration. In addition, the present invention is not limited to use with wind turbine towers but may be utilized in any application having concrete constructions and/or tall towers in addition to wind towers, including for example homes, bridges, tall towers and other aspects of the concrete industry. Further, the methods described herein may also apply to manufacturing any similar structure that benefits from the advantages described herein.

Referring now to <FIG>, a cross-sectional view of a tower structure <NUM> of a wind turbine <NUM> manufactured according to the present disclosure is illustrated. As shown in the illustrated embodiment, the tower structure <NUM> defines a circumferential tower wall <NUM> having an outer surface <NUM> and an inner surface <NUM>. Further, as shown, the circumferential tower wall <NUM> generally defines a hollow interior <NUM> that is commonly used to house various turbine components (e.g. a power converter, transformer, etc.). In addition, as will be described in more detail below, the tower structure <NUM> is formed using additive manufacturing. Moreover, as shown, the tower structure <NUM> is formed of a cementitious material <NUM> that is reinforced with one or more reinforcement elements <NUM>. In particular embodiments, the reinforcement element(s) <NUM> may include, for example, elongated reinforcing cables or wires, reinforcing bars (also referred to as rebar), (hollow or solid), fibers (such as metal, glass, or carbon fibers) and/or any such structures or materials as may be known in the art to reinforce concrete structures. For example, as shown in <FIG>, the tower structure <NUM> may include a plurality of pre-tensioned linear cables <NUM> embedded in the cementitious material <NUM>.

In addition, the cementitious material <NUM> described herein may include any suitable workable paste that is configured to bind together after curing to form a structure. As examples, a cementitious material may include lime or calcium silicate based hydraulically setting materials such as Portland cement, fly ash, blast furnace slag, pozzolan, limestone fines, gypsum, or silica fume, as well as combinations of these. In some embodiments, the cementitious material <NUM> may additionally or alternatively include non-hydraulic setting material, such as slaked lime and/or other materials that harden through carbonation. Cementitious materials may be combined with fine aggregate (e.g., sand) to form mortar, or with rough aggregate (sand and gravel) to form concrete, including both cement-based and non-cement based concretes. For example, in certain embodiments, the cementitious material may include geopolymer concrete, biopolymer concrete, or any other suitable concrete. A cementitious material may be provided in the form of a slurry, which may be formed by combining any one or more cementitious materials with water, as well as other known additives, including accelerators, retarders, extenders, weighting agents, dispersants, fluid-loss control agents, lost-circulation agents, strength-retrogression prevention agents, free-water/free-fluid control agents, expansion agents, plasticizers (e.g., superplasticizers such as polycarboxylate superplasticizer or polynaphthalene sulfonate superplasticizer), and so forth. The relative amounts of respective materials to be provided in a cementitious material may be varied in any manner to obtain a desired effect.

Referring now to <FIG>, the present disclosure is directed to systems and methods for manufacturing tower structures, such as wind turbine towers, via additive manufacturing. Additive manufacturing, as used herein, is generally understood to encompass processes used to synthesize three-dimensional objects in which successive layers of material are formed under computer control to create the objects. As such, objects of almost any size and/or shape can be produced from digital model data. It should further be understood that the additive manufacturing methods of the present disclosure may encompass three degrees of freedom, as well as more than three degrees of freedom such that the printing techniques are not limited to printing stacked two-dimensional layers but are also capable of printing curved and/or irregular shapes.

Referring particularly to <FIG>, a perspective view of one embodiment of a system <NUM> for manufacturing a tower structure <NUM> according to the present disclosure is illustrated. As shown, the system <NUM> includes a supporting frame assembly <NUM> moveable in a vertical direction of the tower structure <NUM>. More specifically, as shown in <FIG> and <FIG>, the supporting frame assembly <NUM> includes a ring-shaped platform assembly <NUM> supported by a plurality of rod members <NUM>. The ring-shaped platform assembly includes a platform <NUM> supporting an outer ring support member <NUM> and an inner ring support member <NUM> arranged concentrically with each other with the plurality of rod members extending therebetween <NUM>.

In particular embodiments, the outer and inner ring support members <NUM>, <NUM> may each have an adjustable diameter. For example, as shown in <FIG>, the outer and inner ring support members <NUM>, <NUM> may be segmented, with the segments <NUM> joined together via slidable, hollow sleeves <NUM>. Thus, as shown, the slidable, hollow sleeves <NUM> are configured to receive varying lengths of the segments <NUM> so as to adjust the diameter of the outer and inner ring support members <NUM>, <NUM>. In certain embodiments, the hollow sleeves <NUM> and/or the segments <NUM> may be sufficiently flexible to enable the radius of curvature to change over the range of tower diameters. Accordingly, the outer and inner ring support members <NUM>, <NUM> can be adjusted to accommodate tower structures of varying sizes.

Referring now particularly to <FIG> and <FIG>, the system <NUM> may include a lifting jack <NUM> that is moveable along each of the plurality of rod members <NUM> so as to move the supporting frame assembly <NUM> in the vertical direction V, i.e. by raising the outer and inner ring support members <NUM>, <NUM> continuously or incrementally. In certain embodiments, the lifting jacks <NUM> may be hydraulically-driven screw jack. In further embodiments, the lifting jacks <NUM> may be driven using any suitable means, such as pneumatic, mechanical, etc. Thus, by lifting the lifting jack(s) <NUM>, the supporting frame assembly <NUM> can be lifted to any desired height.

Referring particularly to <FIG>, the system <NUM> also includes an additive printing assembly <NUM> secured to the supporting frame assembly <NUM>. It should be understood that the additive printing assembly <NUM> described herein generally refers to any suitable additive printing device having one or more nozzles or printer heads for depositing material (such as the cementitious material described herein) onto a surface that is automatically controlled by a controller to form an object programmed within the computer (such as a CAD file). More specifically, as shown, the additive printing assembly <NUM> may include at least one printer head <NUM>, <NUM> configured to dispense a first cementitious material <NUM>. For example, in an embodiment, as shown in <FIG>, the printer head(s) <NUM>, <NUM> of the additive printing assembly <NUM> may include, at least, an outer printer head <NUM> for printing an outer wall <NUM> of the tower structure <NUM> and an inner printer header <NUM> for printing an inner wall <NUM> of the tower structure <NUM>.

In addition, as shown, the additive printing assembly <NUM> may also include an intermediate printer head <NUM> secured between the outer and inner printer heads <NUM>, <NUM>. As such, in certain embodiments, the intermediate printer head <NUM> may be a pump for filling an area <NUM> between the outer and inner tower walls <NUM>, <NUM> with a second cementitious material <NUM> may be different than the first cementitious material <NUM>. In particular, in one embodiment, the first cementitious material <NUM> may be a fast-setting concrete. Therefore, the printed outer and inner walls can harden very quickly and can thus hold hydrostatic pressure of poured concrete. Accordingly, the second cementitious material <NUM> may be a self-compacting cementitious material. In further embodiments, the additive printing assembly <NUM> may include any suitable number of printer heads including more than three printer heads or less than three printer heads.

Referring now to <FIG>, the system <NUM> also includes a reinforcement dispensing assembly <NUM> supported by the supporting frame assembly <NUM>. Thus, the reinforcement dispensing assembly <NUM> is configured to automatically and continuously dispense a plurality of reinforcing members <NUM> as the tower structure <NUM> is printed and built up via the printer head(s) <NUM>, <NUM>, <NUM> and as the supporting frame assembly <NUM> moves in the vertical direction V. For example, as shown in <FIG> and <FIG>, the reinforcement dispensing assembly <NUM> may include a plurality of roller devices <NUM>. In such embodiments, the reinforcing members <NUM> may be reinforcing cables <NUM> or wires. In such embodiments, the reinforcing cables <NUM> may be dispensed from the roller devices <NUM>, e.g. by automatically and continuously rolling the reinforcing cables <NUM> therefrom under tension. Further, in an embodiment, as shown in <FIG>, the roller devices <NUM> may be arranged atop the outer or inner ring support members <NUM>, <NUM>.

Alternatively, as shown in <FIG>, the reinforcement dispensing assembly <NUM> may include a plurality of pulley blocks <NUM> with one of the plurality of pulley blocks <NUM> being arranged with each of the plurality of roller devices <NUM>. Accordingly, as show, the pulley blocks <NUM> may be arranged atop the outer or inner ring support members <NUM>, <NUM> and the roller devices <NUM> may be arranged lower than the pulley blocks <NUM>, such as on the ground.

Referring to <FIG>, in alternative embodiments, the reinforcement dispensing assembly <NUM> may include a plurality of feeder devices <NUM> arranged atop the outer or inner ring support members <NUM>, <NUM>. In such embodiments, the reinforcing members <NUM> may be reinforcing bars <NUM>. Accordingly, as shown, the reinforcing bars <NUM> may be dispensed from the feeder devices <NUM> by automatically and continuously pushing the reinforcing bars <NUM> therefrom.

Referring particularly to <FIG>, a flow diagram of one embodiment of a method <NUM> for manufacturing a tower structure <NUM> according to the present disclosure is illustrated is illustrated. In general, the method <NUM> will be described herein with reference to the tower structure <NUM>, such as a wind turbine tower, formed using the system <NUM> shown in <FIG>. However, it should be appreciated that the disclosed method <NUM> may be implemented to form other similar tower structures having any other suitable configurations. In addition, although <FIG> depicts steps performed in a particular order for purposes of illustration and discussion, the methods discussed herein are not limited to any particular order or arrangement.

As shown at (<NUM>), the method <NUM> includes providing the supporting frame assembly <NUM> described herein. As shown at (<NUM>), the method <NUM> includes arranging the additive printing assembly <NUM> and the reinforcement dispensing assembly <NUM> with the ring-shaped platform assembly <NUM> of the supporting frame assembly <NUM>. As shown at (<NUM>), the method <NUM> includes raising the ring-shaped platform assembly <NUM> to a certain distance in the vertical direction V by moving the ring-shaped platform assembly <NUM> along the plurality of rod members <NUM>, e.g. via a plurality of lifting jacks <NUM>.

While the ring-shaped platform assembly <NUM> is being lifted or after, as shown at (<NUM>), the method <NUM> includes dispensing a plurality of reinforcing members <NUM> from the reinforcement dispensing assembly <NUM>. For example, as mentioned, in an embodiment, the reinforcing member(s) <NUM> may be reinforcing cable <NUM> that is unwound from a rolling device <NUM> under tension. Alternatively, as mentioned, the reinforcing member(s) <NUM> may be reinforcing bars <NUM> that are pushed down and into a space that will ultimately be filled or printed with cementitious material.

It should be understood that the reinforcing member(s) <NUM> may extend along the entire height of the tower structure <NUM> or along only a portion of the tower height. In addition, in such embodiments, the additive printing assembly <NUM> is configured to print the cementitious material around the reinforcing member(s) <NUM>. In alternative embodiments, the reinforcement dispensing assembly <NUM> may be configured to provide tension to the reinforcing member(s) <NUM>, such as when the member(s) are cables, during printing of the tower structure <NUM> and/or during lifting of the supporting frame assembly <NUM>. In such embodiments, the method <NUM> may also include varying a tension of the one or more reinforcing member(s) <NUM> as a function of a cross-section of the tower structure <NUM> during the printing process. Thus, such reinforcing member(s) <NUM> are configured to manage tensile stresses of the tower structure <NUM>.

Referring still to <FIG>, as shown at (<NUM>), the method <NUM> includes printing, via at least one printer head of the additive printing assembly <NUM>, at least a portion of the tower structure <NUM> via at least one cementitious material so as to embed the dispensed plurality of reinforcing members <NUM> therein. For example, in an embodiment, as shown in <FIG>, the method <NUM> may include printing, via the outer and inner printer heads <NUM>, <NUM> of the additive printing assembly <NUM>, the outer and inner walls <NUM>, <NUM> of the tower structure <NUM> of the first cementitious material <NUM>. Such walls <NUM>, <NUM> may be printed simultaneously to save time or separately, if needed. Then, the method <NUM> may include filling, via the intermediate printer head <NUM> secured between the outer and inner printer heads <NUM>, <NUM>, the area <NUM> between the outer and inner walls <NUM>, <NUM> with the second cementitious material <NUM> so as to completely cast the tower structure <NUM>. This process (i.e. steps <NUM>, <NUM> and <NUM>) can be repeated to complete the tower structure <NUM> up to any suitable height. Moreover, in certain embodiments, the rod members <NUM> of the supporting frame assembly <NUM> may be removed after construction of the tower structure <NUM>, thereby creating holes or channels that can be used as conduits for post-tension bars or cables.

In addition, in certain embodiments, the additive printing assembly <NUM> is configured to print the cementitious material in a manner that accounts for the cure rate thereof such that the tower structure <NUM>, as it is being formed, can bond to itself. In addition, the additive printing assembly <NUM> is configured to print the tower structure <NUM> in a manner such that it can withstand the weight of the walls <NUM>, <NUM> as the additively-formed cementitious material can be weak during printing. Thus, the reinforcement element(s) <NUM> of the tower structure <NUM> are provided to enable the tower to withstand wind loads that can cause the tower <NUM> to be susceptible to cracking.

Referring now to <FIG>, a block diagram of one embodiment of a controller <NUM> configured to control the additive printing assembly <NUM> described herein is illustrated. As shown, the controller <NUM> may include one or more processor(s) <NUM> and associated memory device(s) <NUM> configured to perform a variety of computer-implemented functions (e.g., performing the methods, steps, calculations and the like and storing relevant data as disclosed herein). Additionally, the controller <NUM> may also include a communications module <NUM> to facilitate communications between the controller <NUM> and the various components of the additive printing assembly <NUM>. Further, the communications module <NUM> may include a sensor interface <NUM> (e.g., one or more analog-to-digital converters) to permit signals transmitted from one or more sensors <NUM>, <NUM> to be converted into signals that can be understood and processed by the processor(s) <NUM>. It should be appreciated that the sensors may be communicatively coupled to the communications module <NUM> using any suitable means. For example, as shown in <FIG>, the sensors <NUM>, <NUM> may be coupled to the sensor interface <NUM> via a wired connection. However, in other embodiments, the sensors <NUM>, <NUM> may be coupled to the sensor interface <NUM> via a wireless connection, such as by using any suitable wireless communications protocol known in the art. As such, the processor(s) <NUM> may be configured to receive one or more signals from the sensors.

As used herein, the term "processor" refers not only to integrated circuits referred to in the art as being included in a computer, but also refers to a controller, a microcontroller, a microcomputer, a programmable logic controller (PLC), an application specific integrated circuit, and other programmable circuits. The processor(s) <NUM> is also configured to compute advanced control algorithms and communicate to a variety of Ethernet or serial-based protocols (Modbus, OPC, CAN, etc.). Additionally, the memory device(s) <NUM> may generally comprise memory element(s) including, but not limited to, computer readable medium (e.g., random access memory (RAM)), computer readable non-volatile medium (e.g., a flash memory), a floppy disk, a compact disc-read only memory (CD-ROM), a magnetooptical disk (MOD), a digital versatile disc (DVD) and/or other suitable memory elements. Such memory device(s) <NUM> may generally be configured to store suitable computer-readable instructions that, when implemented by the processor(s) <NUM>, configure the controller <NUM> to perform the various functions as described herein.

Claim 1:
A system for manufacturing a structure, the system comprising:
a supporting frame assembly (<NUM>) moveable in a vertical direction of the structure;
an additive printing assembly (<NUM>) secured to the supporting frame assembly, the additive printing assembly comprising at least one printer head (<NUM>, <NUM>) configured to dispense a first cementitious material (<NUM>); and,
a reinforcement dispensing assembly (<NUM>) supported by the supporting frame assembly, the reinforcement dispensing assembly configured to automatically and continuously dispense a plurality of reinforcing members (<NUM>) as the structure is printed and built up via the at least one printer head and as the supporting frame assembly moves in the vertical direction;
wherein the supporting frame assembly comprises at least one ring-shaped platform assembly (<NUM>) supported by a plurality of rod members (<NUM>); and
wherein the at least one ring-shaped platform assembly comprises a platform (<NUM>) supporting an outer ring support member (<NUM>) and an inner ring support member (<NUM>) arranged concentrically with each other with the plurality of rod members extending therebetween.