STRUCTURE AND ACCELERATOR PLATFORM PLACEMENT FOR A WIND TURBINE TOWER

BACKGROUND

It is the general object of the present invention to provide an improved wind turbine and tower for mounting wind turbines, as well as improved methods for manufacturing thereof and associated systems, components, methods, devices, and electronics.

SUMMARY

Disclosed herein is a structure for a wind turbine tower. The structure includes a plurality of corner posts forming the core of the tower, one or more cross braces spanning the distance between at least one pair of corner posts, at least one rotating support member mounted at the location of at least one corner post, at least two accelerator platforms attached to the at least one rotating support member, wherein each accelerator platform can rotate on at least one rotating support member, and at least two horizontal-axis wind turbines mounted on opposite sides of the at least one accelerator platform. In some embodiments, the vertical spacing between the rotating support member from the at least one accelerator platform to an adjacent accelerator platform is substantially an integer multiple of the vertical spacing between the intersection points between the cross braces and the corner posts. In other embodiments, the rotating support member locations on the corner posts are proximal to the intersection of the cross braces and the corner posts.

Two or more accelerator platforms may be mounted on the tower in a vertical stacking arrangement, may be linked in such a way that they always point in substantially the same direction relative to rotation about the vertical Z axis, or may be linked by a spring to enable movement in the X and Y axes and wherein the force of the spring acts to return the accelerator platforms to an aligned configuration. The cross braces may be angled. The power and communication wires between the rotating platforms and a non-rotating part of the facility may traverse at least part of the core of the tower vertically so that the wires can twist a plurality of turns in either direction as the platforms rotate. The wires may come from two or more wind-turbine generators on the platforms. The vertical location of the rotating support member attachment points to the corner posts may be within a pre-defined distance of where the cross braces intersect the corner posts, wherein the pre-defined distance is a percentage of the spacing between intersection points between the cross braces and the corner posts. The percentage may be +/−25%.

Disclosed is a method of assembling a wind turbine blade and impeller blade hub including injection molding an impeller blade including a connection feature at the root end of the blade, injection molding the impeller hub including a hub connection feature that is complementary to the connection feature at the root end of the blade, and mounting one or more impeller blades to the impeller hub by mating the connection feature at the root end of the blade with the complementary hub connection feature to form an impeller blade assembly. At least one of the impeller blades and the impeller hub is injection molded out of plastic, such as glass-fiber filled or carbon-fiber filled plastic, and may utilize a gas assist. The connection feature and hub connection feature may enable fastening via at least one of an interference fit, a friction fit, a ball and socket, a zipper, a snap fit, a threaded fit, a hook and loop, an eyelet, and a clip. The injection molded impeller blade may be hollow. The method may further include mounting a nose cone to the impeller blade assembly, if a nose cone feature is not already integrated into the impeller hub. The nose cone may be injection molded. The method may further include mounting the impeller blade assembly on a generator shaft of a wind turbine. The method may further include first mounting the impeller blade assembly on an adaptor hub before mounting to the generator shaft or first mounting an adaptor hub to the generator shaft before mounting the impeller blade assembly on the adaptor hub. The wind turbine may be adapted to be mounted on an accelerator platform that rotates around a tower on at least one rotating support member. Closed-cell foam may be injected into air cavities of the impeller blade assembly. The impeller blade assembly may be balanced by adding a weight to the hub, such as by mounting through an opening in the hub, optionally with bolts that self tap into plastic features in the hub. The impeller blade assembly may be disassembled and re-assembled without having to rebalance the assembly.

Disclosed herein is a method of manufacturing a flange for connecting structural members of a wind turbine tower. The method may include hot rolling steel and forming it to an approximately cylindrical shape or a flat sheet. The method may also include heating and forging the approximately cylindrical steel shape to form it into a flange shape. If the hot rolled steel is flat, the method may include cutting the flat steel into an approximately cylindrical steel shape before heating and forging to form it into a flange shape. The method may conclude with cooling the flange and machining the inside and outside surfaces of the flange to their final shape. The flange material may include a carbon content less than 0.3% or a carbon equivalent. The carbon equivalent is defined by an equation, such as CE=% C+((% Mn+% Si)/6)+((% Cr+% Mo+% V)/5)+((% Cu+% Ni)/15), less than 0.45%, or any other equation for calculating carbon equivalency. The flange material may include an element to retard grain growth during heating above an austentizing temperature, such as 1000 degrees Fahrenheit. The flange material may include at least one of titanium, niobium, ruthenium, vanadium, zirconium, molybdenum, a rare earth element, a transition metal, and a combination thereof. The flange material may include a grain size (G) of 12 or smaller as measured using ASTM E112. The flange material may include at least one of austenite dispersed in a ferrite microstructure, pearlite dispersed in a ferrite microstructure, carbide precipitates in a ferrite microstructure, and nitride precipitates in a ferrite microstructure. The flange may be welded to the tubular member, such as via a multipass metal inert gas (MIG) weld or an inside tungsten inert gas (TIG) pass weld. The assembly may be galvanized after welding. The flange may define a circumaxially spaced series of small axially extending openings for receiving bolts. The final shape of the flange may be radial annular with at least a partial generally planar surface on one side. The flange may be part of a flanged coupling unit for use with a similar coupling unit in oppositely oriented interconnected mating relationship for the endwise interconnection of the structural members. The structural members may be axially aligned similar elongated members.

The flanged coupling unit may include the radially extending generally annular flange having at least a partially generally planar radial surface on one side, a rigid connector for connecting the flange with a mating flange of a similar coupling unit with the planar surfaces of the two flanges engaged in face-to-face relationship, and a boss formed integrally at its inner end portion with the flange to form an external corner surface area therewith on the side thereof opposite its planar surface and projecting axially therefrom for connection with an end portion of a first elongated member, the mating flange having a similar boss for connecting a second elongated member in endwise axially aligned relationship with the first member, and the external surfaces oppositely adjacent to and through the corner area between the flange and boss being substantially arcuate concave throughout deriving from substantially continuously varying radii of curvature between a first imaginary annular line spaced outwardly along and extending around the boss and a second imaginary annular line spaced outwardly along and extending around the flange, opposite ends of the arcuate surface respectively adjacent the first and second imaginary annular lines blending smoothly in transition to a linear surface on the opposite side of the line, the largest radius of curvature being adjacent the first imaginary annular line and the smallest radius of curvature adjacent the second imaginary annular line, and the first imaginary line being substantially farther from the corner between the boss and flange than the second imaginary line.

Disclosed herein is a wind power generating system that includes at least two wind turbines comprising impeller blades, wherein the turbines are mounted on a horizontally rotatable support in spaced relationship with each other on opposite sides of the axis of the support for rotation about horizontal axes, each turbine being connected in driving relationship with an electrical generator, which is in turn connected to an external load. The system may also include at least two DC converters and power switches respectively receiving the output of said generators, at least two monitors each sensing at least one parameter of operation of one generator, a controller connected with and receiving signals from said monitors and including a reference in the form of a performance curve for said generators, wherein said controller is connected in controlling relationship with each of said generators such that at least one generator follows the performance curve to generate power, and at least one resistor in electrical communication with at least one DC bus that transfer signals between the DC converter and at least one inverter. The resistor may dissipate the power when a monitor determines a dissipation-requiring condition. The dissipation-requiring condition may be at least one of: that at least one generator is not following the performance curve, that power drawn by the generator exceeds the capacity of the at least one inverter, that the power drawn by the generator exceeds the capacity of a utility grid connection, and that the utility grid fails. Substantially all of the power may be dissipated in the at least one resistor while the impeller blades are decelerated. The system may include various combinations of resistors and inverters, such as two resistors and two inverters, one resistor and one inverter, two resistors and one inverter, one resistor and two inverters, and the like.

Disclosed herein is a method of braking in a wind turbine generator including attaching at least one brake set to the rear of a wind turbine generator, wherein the brake set is spring-applied, pneumatically released, connecting at least one air pressure system to the brake set, connecting a solenoid valve in line with the brake set to control an air pressure from the at least one air pressure system at the generator brake, pressurizing the brake to release when the solenoid valve has voltage on its coil, and venting the brake to engage when there is no voltage on its coil. The at least one air pressure system comprises at least one compressor. The at least one compressor may be located on a non-rotating portion of a tower where the wind turbine generator is mounted or a rotating portion of a tower where the wind turbine generator is mounted. The single air pressure system may power a plurality of brake sets. The plurality of air pressure systems may power one or more brake sets.

In another method of braking in a wind turbine generator, the method may include attaching at least one brake set to the rear of at least one wind turbine generator, connecting at least one air pressure system to the brake set, wherein the at least one air pressure system is controlled by a solenoid valve, and applying an air pressure through the air pressure system to the at least one brake set to release and venting the air pressure at the least one brake set to engage. The brake set may be spring-applied, pneumatically released. 9. The method of claim 7, wherein the air pressure system comprises at least one compressor. The at least one air pressure system comprises at least one compressor. The at least one compressor may be located on a non-rotating portion of a tower where the wind turbine generator is mounted or a rotating portion of a tower where the wind turbine generator is mounted. The single air pressure system may power a plurality of brake sets. The plurality of air pressure systems may power one or more brake sets.

Disclosed herein is a large monolithic twin-sheet thermoformed panel for use as a wind engaging arcuate convex exterior covering on a generally cylindrical accelerator mounted at an elevated position on a tower supports at least one pair of wind turbines for generating electricity; said panel having a smooth continuous exterior surface for engaging the wind and directing the same in separate streams of air toward the turbines, an interior surface comprising a multiplicity of small projections enhancing the structural integrity of the panel and a structural foam enhancing the strength of the panel, narrow elongated edge portions on all sides of substantially reduced thickness overlapping like edge portions of adjacent panels, at least one notch for receiving and tightly fitting a structural mounting member and preventing relative rotation of the panel, and a connector for fixedly mounting the panel on the structural member so as to accommodate full expansion and contraction of the panel. Second and third notches may be provided respectively at opposite ends of the interior surface of the panel each in spaced relationship with the first notch, the second and third notches accommodating second and third structural members with provision for panel expansion and contraction and with resistance to panel stressing for firm engagement with the structural member. At least three small spaced apart projections may be provided with at least one on a first side of the panel notch and with at least two on an opposite side for firm engagement with the structural member and for prevention of relative rotation of the panel. A bolt opening may be provided and an annular flange may be provided to support the panel and to recess the head of a bolt entered in the bolt opening so as to provide a smooth uninterrupted wind flow surface on the exterior of the panel. The small projections on the interior surface of the panel may generally be cone shaped. The panel may be substantially rectangular with approximately fifty (50) rows of projections in one direction and approximately eighty two (82) rows in the other direction.

Disclosed herein is a method of forming a large monolithic lightweight thermoplastic panel including the steps of positioning a pair of similar large blank sheets of thermoplastic in the shape of the panel in parallel face-to-face relationship between first and second thermal forming molds, vacuum drawing and thermoforming the sheets so that a first sheet has a smooth continuous external surface and a second sheet has a multiplicity of small spaced apart projections substantially throughout the side opposite the first sheet, the projections on the second sheet being simultaneously fused with the first sheet to form an integral monolithic final panel which is lightweight yet exhibits a high degree of structural integrity; and injecting the interior of the panel with a structural foam. The projections take substantially a cone shape. There may be approximately sixty rows of cones in one direction and approximately one hundred and four rows of cones in the other direction. The plastic may be polyethylene. The plastic may be high-density high molecular weight polyethylene. A central notch may be formed in the second sheet with a through bolt hole centrally located in both sheets. At least two spaced apart small projections may be molded in each wall of the notch for a press fit engagement with a structural member entered in the notch. Second and third notches may be formed in the second sheet of plastic in spaced relationship with the first notch. Each edge portion of the panel may be formed with an elongated portion of reduced thickness.

These and other systems, methods, objects, features, and advantages of the present invention will be apparent to those skilled in the art from the following detailed description of the preferred embodiment and the drawings.

All documents mentioned herein are hereby incorporated in their entirety by reference. References to items in the singular should be understood to include items in the plural, and vice versa, unless explicitly stated otherwise or clear from the text. Grammatical conjunctions are intended to express any and all disjunctive and conjunctive combinations of conjoined clauses, sentences, words, and the like, unless otherwise stated or clear from the context.

BRIEF DESCRIPTION OF THE FIGURES

The invention and the following detailed description of certain embodiments thereof may be understood by reference to the following figures:

FIG. 1 depicts a schematic perspective showing a tower, a cylindrical accelerator and wind turbines mounted thereon;

FIG. 2 depicts a schematic top view showing a tower, a cylindrical accelerator and a pair of wind turbines with three hundred sixty (360) degree diffusers shown in section;

FIG. 3A depicts a block diagram illustrating twin turbines and their associated generators and control system with a resistor disposed in parallel with the DC bus;

FIG. 3B depicts a block diagram illustrating twin turbines and their associated generators and an improved AC output system;

FIG. 4 depicts a schematic illustration of Four Quadrant or Regenerative Drive Circuitry monitored by the controller to determine either generator or motor operation;

FIG. 5 depicts an enlarged schematic of a pair of vertically adjacent accelerators with the skin members somewhat transparent to show at least partially the support structures;

FIG. 6 depicts an enlarged view of a joint area between vertically adjacent accelerators;

FIG. 7 depicts an enlarged perspective view of an accelerator showing the support structure;

FIG. 8A depicts a schematic front view of a turbine with forwardly swept blades in accordance with the invention;

FIG. 8B depicts a schematic side view of a turbine illustrating blades with a rearward linear rake;

FIG. 8C depicts a schematic view of a turbine having blades with a gradually curved rearward rake;

FIG. 8D depicts a schematic view of a turbine with blades which have an outer portion with a rearward rake;

FIG. 9 depicts a schematic front view of a turbine with unequal blade spacing;

FIG. 10A depicts an enlarged illustrative view of a wind turbine, hub, shroud and completed vane assembly;

FIG. 10B depicts an enlarged view of an illustrative wind turbine, hub, shroud and exposed structural member assembly;

FIG. 11A depicts an enlarged cross-sectional view of a structural member and sheath forming a vane assembly;

FIG. 11B depicts a perspective view of a sheath;

FIG. 11C depicts a fragmentary view showing a sheath and structural member of a vane assembly;

FIG. 12 depicts a somewhat schematic vertical section through a wind turbine showing the relationship of an annular shroud or blade tip ring and an adjacent stationary ring;

FIG. 13 depicts an enlarged view of a portion of FIG. 12 showing sealing means and the relationship thereto of the annular ring about the blades and the associated stationary ring;

FIG. 14 depicts a plan view of a single panel of the invention;

FIG. 15 depicts a fragmentary enlarged side view of the FIG. 14 panel;

Fig. depicts an exploded side view of a panel and associated structural members prior to mounting the panel on the members;

Fig. depicts is a fragmentary exploded and enlarged side view showing the panel and structural members of FIG. 15;

FIG. 18 depicts further enlarged view in perspective and showing edge portions of a pair of panels;

FIG. 19 depicts a side view similar to FIG. 17 but showing a panel partially attached to a structural member;

FIG. 20 depicts a fragmentary enlarged exploded side view similar to FIGS. 16 and 17 showing a panel partially attached to a structural member;

FIG. 21 depicts an enlarged vertical cross sectional view of a panel taken through a central portion thereof;

FIG. 22 depicts a perspective view in cross section taken through a central portion of a panel;

FIG. 23 depicts an enlarged cross sectional view through an overlapping vertical joint between panels;

FIG. 24 depicts an enlarged sectional view and showing a joint panel and its mounting means;

FIG. 25 depicts a cross sectional view through an open thermoforming mold for the panels;

FIG. 26 depicts a fragmentary enlarged view through a portion of the mold of FIG. 25;

FIG. 27 depicts a view similar to FIG. 25 but showing the mold closed;

FIG. 28 depicts a somewhat schematic sectional view of a joint construction of the present invention;

FIG. 29 depicts schematic sectional view taken generally as indicated at 2-2 in FIG. 28;

FIG. 30 depicts a view of a small insert used between the male member and an adjacent shoulder on the female member;

FIG. 31 depicts a view showing a locating pin employed as a self-fixturing means;

FIG. 32 depicts a view showing a pair of locating pins installed prior to the telescopic assembly of the male and female members;

FIG. 33 depicts a view of a female member with integral ribs employed as a centering means;

FIG. 34 depicts a schematic perspective showing an adhesive distributing device mounted on an assembled male-female joint;

FIG. 35 depicts a fragmentary cross-sectional enlarged view showing a notch and chamfer in an open end of a female member, the locating pins thus being guided into an adjacent adhesive chamber;

FIG. 36 depicts a fragmentary cross-sectional enlarged view showing a notch and chamfer in an open end of a female member, the locating pins thus being guided into an adjacent adhesive chamber;

FIG. 37 depicts a fragmentary cross-sectional enlarged view showing a short centering means formed integrally on the interior surface of a female member in spaced relationship with the mouth of the member, the centering means serving to center the free end of a male member entered in the female member;

FIG. 38 depicts a sectional view through the adhesive distributing device;

FIG. 39 depicts a side elevation in section of an improved flanged coupling unit in accordance with the present invention;

FIG. 40 depicts a side elevation in section of a second embodiment of an improved flanged coupling unit in accordance with the present invention;

FIG. 41 depicts a side elevation of a ‘third embodiment of an improved flanged coupling unit in accordance with the present invention;

FIG. 42 depicts a schematic view of a tower employing a number of improved flange coupling units interconnecting elongated tubular structural Members;

FIG. 43 depicts an enlarged sectional view of an assembled coupling employing a pair of similar units with flanges bolted together to interconnect hollow tubular structural units as in FIG. 42;

FIG. 44 depicts a view similar to FIG. 43, but employing an alternative means in the form of a clamp connecting the flanged coupling units;

FIG. 45 depicts an enlarged elevational view in section showing an improved coupling unit used individually in mounting an elongated generally vertical support member for a wind tower or the like;

FIG. 46 depicts an enlarged fragmentary perspective view showing a manifold and lower end portions of an outrigger comprising three (3) tubular members with a three member foundation;

FIG. 47 depicts an enlarged fragmentary perspective showing a manifold and a connecting bracket associated with a three member foundation and main structural member of a tower;

FIG. 48 depicts a fragmentary sectional view showing a guide and manifold with associated foundation members during drilling and formation of the micro pile;

FIG. 49 depicts a view in elevation showing the tower, wind turbines and supporting structures mounted thereon, outriggers in place about the base of the tower with foundation members supporting the tower and outriggers;

FIG. 50 depicts a fragmentary view in elevation showing a lower portion of the tower and outriggers in greater detail;

FIG. 51 depicts a fragmentary illustration in perspective of the erection apparatus of the present invention connected with a tower to be erected;

FIG. 52 depicts a schematic side view of the apparatus and tower of FIG. 50 demonstrating the erection procedure;

FIG. 53 depicts a further schematic view showing the tower in a position of substantial erection where the cylinders commence a resistive action;

FIGS. 54A and 54B depicts an enlarged view in section showing a pivotal support for the tower and the connection of an elongated member to the tower; and

FIG. 55 depicts a perspective view showing the apparatus of the invention disconnected from the tower and in a preliminary substantially horizontal attitude.

FIGS. 56A and B depict a top-down and section view, respectively, of a tower for mounting a wind turbine and an accelerator platform.

FIG. 57A depicts an impeller blade and FIG. 57B depicts an enlarged view of the blade root.

FIG. 58 depicts an impeller hub.

FIG. 59A depicts an impeller blade assembly and FIG. 59B depicts an enlarged view of the assembly.

DETAILED DESCRIPTION

Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting, but rather to provide an understandable description of the invention.

Referring to FIG. 1, a wind turbine installation may be indicated generally at 100 with a tower 102, a cylindrical accelerator 104, and six (6) pairs of wind turbines 108, 108 mounted in vertically stacked relationship on opposite sides of the tower. The accelerator 104 may vary widely in construction and configuration but is preferably cylindrical as shown and serves to divide wind impinging thereon into a pair of discrete diverging and accelerating streams of air for flow around opposite sides thereof before entering the turbine. Further, the accelerator may be preferably of sufficient vertical dimension to accommodate a plurality of pairs of wind turbines, such as six shown in FIG. 1.

Wind turbines 108, 108 may be conventional and may be mounted in vertically stacked relationship by means of spars 110, 110 projecting from accelerator 104. Various means of mounting the wind turbines may be contemplated including cantilevered struts as shown, multiple struts spaced angularly around the hub and other arrangements common in fan design.

Disclosed herein are gaps between the wind turbine blades and the accelerator platform surface. These gaps act to reduce the downstream wake, which may result in a net increase in flow through the turbine in spite of some air bypassing the turbine. In combination with the gaps, a simple cylinder may be used as the accelerator shape, stacking up multiple accelerators vertically, and either blocking or using a mesh material in the gaps. In combination with the gaps, diffuser shrouds may be disposed around each turbine. Thus, any combination of accelerator shapes, gaps, and shrouds in a twin-turbine wind power generating system may be used. The accelerator may have a converging portion rearwardly of the turbines. The front portion of the accelerator may have a convex arcuate configuration.

Each wind turbine 108 may include means defining an associated front to rear bypass opening. The openings may be formed by naturally occurring gaps defined between a generally tangential portion of an adjacent accelerator surface and the sweep formed by tip portions of the turbine blades above and below the adjacent accelerator surface portion. As illustrated in FIG. 1, gaps may be shown at 112, 112 and take the configuration of upper and lower triangles in reverse orientation. A wide variety of other bypass opening designs may also be contemplated. Still referring to FIG. 1 the uppermost gaps 112, 112 may preferably open but, optionally, may be provided with closing means 114, 114 and the gaps 112, 112 may also have a mesh-like material 118, 118 disposed therein as in the turbines there below.

In embodiments, a diffuser shroud may be disposed about each turbine which diverges rearward of the turbine. Shrouds 120, 120, as depicted in FIG. 1, may extend about the outer 180° of the turbines with integral flat supporting spars 122, 122 extending inwardly to the accelerator 104. The diffuser shrouds may continue around on the side adjacent the accelerator, in which case, the supporting spars will be structural only and not part of the shrouds. The diffuser shrouds may be truncated along spaced upper and lower horizontal planes adjacent turbine blade tips to permit close spacing of the wind turbines.

Referring to FIG. 2 a schematic top view showing a tower, a cylindrical accelerator and a pair of wind turbines 108, 108 is illustrated. The diffusers 202, 202 (shown in section) may extend through 360° and completely surround a turbine 108, diverging rearwardly of the turbine. Both diffuser designs as well as other configurations may provide additional turbine performance improvement as described herein.

Further, adjusting the accelerator and wind turbines carried thereby angularly relative to wind direction may include using a ring gear 124 mounted on the accelerator 104, a spur gear 128 driving the ring gear 124 and a small electric motor 130 rotating the spur gear in one and an opposite direction. A controller 208 may respond to a wind direction sensor 210 and in turn monitor operation of the motor 130.

The controller may also respond to signals from the sensor and rotate the turbines to a safe angular position out of the wind when dangerously high winds occur, as in the event of a hurricane.

The aggregate effect of the cylindrical accelerator, the bypass openings adjacent the turbines and the diffusers about the turbines may result in a substantial improvement in performance accompanied by significant savings in manufacturing cost. Angular adjustment of the turbines in unison on the accelerator may also result in substantial savings, such as for example in wiring costs and in the costs associated with individual adjusting means for the turbines.

Disclosed herein is a method for steering a wind power generating system that has two turbines on opposite sides of a vertical rotational axis by adjusting the load on at least one of the generators so as to create a thrust imbalance between the two sides, causing the entire system to rotate about its vertical rotational axis to a new angular position. The implementation of the method includes using a wind direction sensor as part of the control system, using a permanent magnet AC generator, adjusting the PWM duty cycle of the rectifier power electronics as the means of adjusting the load, and the use of the method for turning the system in or out of the wind based on power measurements, which is a possible method of furling the twin turbine system.

Also disclosed is a power electronics architecture in combination with the twin turbine system. Two architectures for the boost converter and inverter are disclosed: the first is a dedicated inverter for each boost converter in the system and the second is a single inverter accepting power from a pair of boost converters.

Also disclosed is the use of the power electronics to drive at least one generator as a motor. Disclosed is the use of at least one motor-driven impeller blade to generate thrust, much like the prop of an airplane, that can rotate the wind generating system about its vertical rotational axis. Using thrust from the turbines to rotate a twin turbine wind generating system may be independent of which direction the wind is coming from or if the wind is blowing at all.

Referring now to FIG. 3, it will be obvious that all four turbine generator control systems may be identical with A1 and B1 representing turbines in common on a first accelerator and A1 and B1 representing turbines mounted in common on other accelerators. The A1 system will be described as representative. Each turbine may be connected in driving relationship with an electrical generator in turn connected with an external load. Turbine 108 drives AC generator 302 which may be conventional and of a variety of different constructions, such as a three-phase or permanent magnet type. In the three-phase type, the current and voltage of at least one phase are sensed. DC boost converter 304 may be conventional with variable pulse width capability and has at least one sensor for monitoring parameters and preferably speed, voltage and current sensors associated therewith and connected with the controller 308. Speed may be measured by the controller by sensing the frequency of the AC signal from the generator. A support position sensor is included and advises the controller of the angular position of the support. Controller 308, may be a conventional microprocessor type, receives current and voltage signals from the sensors, calculates power therefrom, and compares the calculated power with a desired power reference in the form of a performance curve. An upper power limit is established by the controller, the latter serving to adjust the angular position of the support as required to reduce power when said limit is exceeded. A lower power limit is established by the controller, the latter serving to adjust the angular position of the support as required to increase power when said limit is exceeded. In some embodiments, the controller 308 receives meteorological data. A vertical series of supports each carrying a pair of wind turbines are mounted on a vertical tower having stationary sections, and wherein meteorological data gathering devices are mounted on a stationary section and connected with said controller 308. The data may include wind speed, wind direction, and the like.

The controller 308 then adjusts the PWM duty cycle to adjust generator output as required to bring the output into compliance with the desired curve. The PWM of the converters may be selected by comparing a function of voltage and current between the two generators. The controller 308 may adjust the generator output by adjusting the thrust of its associated turbine and thereby adjust the angular position of the accelerator to maintain an optimum angle of attack for the wind relative to the turbine blades. In embodiments, the thrust may be adjusted until the horizontal support stops moving. This may be accomplished by adjusting the relative thrust until the accelerator stops rotating. In embodiments with at least two turbines connected to a generator each, at least one generator follows the performance curve and the other generator adjusts the thrust of its turbine and thereby adjusts the angular position of the horizontally rotatable support.

From the boost converter 304, generator output may proceed conventionally through DC bus 310, inverter 312 which serves the generator 302 or both the generator 302 and a second generator 302a in the system B1, and then in conventional AC form through disconnect switch 314 to grid 318.

The reference performance curve is a current (or power) vs. generator shaft speed curve that may be a target the controller is trying to achieve as the wind speed changes. In accordance with the performance curve, the speed of one or more of the turbines may be reduced at high current (or power) to stall the blades when the wind speed is too high such that the power on the generator shaft is reduced. During fast wind speed increases (e.g. wind gusts), the power drawn by the generator during the transient deceleration time may temporarily exceed the power rating/capacity of the inverter or the utility grid connection. During this time the excess power may be dissipated in a resistor 320, which is shown in the block diagram of FIG. 3A as a component in parallel electrical communication with the DC bus 310. In embodiments, the resistor 320 may comprise more than one discrete resistor connected in series and/or parallel combinations, such as for example, any resistor network that is the Thevenin-equivalent of a single resistor.

Thus, the resistor 320 may be used to help return performance to that dictated by the performance curve, which during a wind gust, for example, would be the lower-speed higher-current portion of the curve. A control algorithm may be programmed in accordance with the performance curve to cause the turbine speed reduction under various programmed conditions.

In the event of a grid failure, all of the power may be dissipated in the resistor 320 while the blades are decelerated to zero speed. Shutdown using the resistor 320 may be in place of or in combination with a mechanical brake, which may be adapted primarily to serve as a parking brake for maintenance or as a brake in an emergency if the power electronics fail. In embodiments, the resistor 320 may be the primary method of stopping the turbines while the mechanical brakes may be the secondary method.

For example, if the utility grid fails while using the generator as a motor to adjust the yaw angle of the turbines, the kinetic energy in the blades can be dissipated in the resistor 320 until the blades stop.

In an embodiment, the back of the generator may connect to a brake set, wherein the brakes may be used to stop the turbine-driven generator from operating.

In an embodiment, two or more generators may be connected to wind turbines on a tower. The brakes on each generator may be spring-applied, pneumatically released, that is, the brakes may need air pressure to release.

In an embodiment, a solenoid valve near each generator may control the air pressure at each generator brake, pressurizing the brake to release when it has voltage on its coil or venting the brake to engage when there is no voltage on its coil. Thus, when the solenoid valve is included in embodiments of the brakes, they are fail-safe brakes, i.e., both air pressure and electrical power are required for them to be released and allow the wind turbines to spin.

In an embodiment, one or more compressors may power the brakes. In embodiments, the compressors may not be located on the rotating part of the tower. In embodiments, the compressors may be located elsewhere on the tower and may have a flexible air hose connection to the brakes that is threaded up the center of the rotating part of the tower to allow it to twist. The compressors may operate in conjunction with or without the solenoid valve in embodiments.

In an embodiment, a single air pressure system may provide air pressure to all brakes on the tower. In other embodiments, two independent air systems may provide the air pressure to the brakes, such as one supplying air to half the generator brakes and the other supplying air to the other half of the generator brakes. In other embodiments, three independent air systems may provide the air pressure, each supplying air to a ⅓ of the generator brakes. In embodiments, an air pressure system may be dedicated to each pair of turbines on a single accelerator platform. It should be understood that any number of independent air systems may be used to provide air pressure to any number of brakes associated with turbine-drive generators on the tower. In any event, the air systems may include the compressors, as previously described herein, located either on the rotating part or the non-rotating part of the tower.

As described elsewhere herein, power cables carrying power from the turbine-driven generator to the ground may be routed down the center of the tower in a so-called twist section, enabling the accelerator platforms to rotate at least a plurality of turns in either direction. In embodiments, the twisting wires may not traverse the complete length of tower. For example, the twist section may be only ˜25% of the height of the tower while the remainder comprises non-flexible wires that do not twist.

In an embodiment, the brakes may feature automatic pad wear adjustment, torque adjustment, quick change pads, modular design and easy maintenance.

The controller 308 may also operate to convert the operation of one or both generators to operation in the mode of motors. This is accomplished by the Four Quadrant or Regenerative Drive Circuitry of FIG. 4 wherein the controller 308 may have two modes of operation. In a first mode of operation the generator 302 may operate as a generator and in the second mode of operation the generator may operate as a motor. When the first bank of switches 314 are operated as a boost converter and the second and third banks of switches 318, 402 as motor controls, the generators operate as motors. In the alternative, when the first bank of switches are operated as an inverter and the second and third bank as boost converters, the generators may be operated as generators. For example, the thrust from running at least one generator as a motor may be employed to adjust the relative position of the turbines. In another example, at least one turbine may be operated as a motor when the wind is blowing predominately in a direction perpendicular to the axis of rotation of the turbines.

Disclosed herein is a structure of the wind accelerating platform in a twin-turbine wind power generating system that is a cage-like structure of thin lightweight supporting members, e.g., a truss, with at least one thin cover member attached to and forming the skin of the structure. Also disclosed are methods of attachment of the skin members that allow for differing thermal expansion coefficients between the truss and the skin. Plastic, either injection-molded or thermo-formed plastic, may be used as a construction material for the skins. Galvanized steel, aluminum, and carbon-fiber composites may be possible materials to build the truss support structure with. Also disclosed is the use of labyrinth seals between accelerator structures stacked vertically on the same tower, which may be useful if the accelerator structures rotated independently.

Referring to FIGS. 5 and 7, a support structure for the accelerator is illustrated at 504, 504 and 508, 508. Generally u-shaped thin support members may be provided in an annular series arrangement to define the three-dimensional outline of the recess 502 which in turn defines an air passageway. Connected with the u-shaped members may be thin annular members 508, 508 which together with the members 504, 504 provide a lightweight but sturdy support structure. The u-shaped members 504, 504 may take the form of trusses as illustrated. Further, structural members may comprise mounting plates 702, 702 which extend vertically and which support the wind turbines 108, 108.

The support members 504, 504 and 508, 508 may be of galvanized steel, aluminum, or a carbon composite. Supported on and about the support members 504, 504 and 508, 508 may be a plurality of cover member sections 512, or panels as elsewhere described herein, as shown in FIG. 6 illustrating an enlarged view of a joint area 510 between vertically adjacent accelerators. Each of the cover member sections 512, 512 takes a generally u-shaped form and the members are arranged in an adjacent relationship with edge portions overlapping. Alternatively, a single large cover member may be provided.

Attachment of the cover member to the support structure may be a completely floating arrangement between the member and the support structure. Alternatively, the cover member may be attached to the support structure at a single area with the remaining portion of the member in a floating relationship with the support member. Annular connecting members 510 interconnect vertically adjacent accelerators and joint areas between the members 510 and 512 are preferably provided with labyrinth seals 602, 602.

The cover member may be an injection-molded thermoplastic, optionally with internal strengthening ribs, or it may be of substantially uniform thickness throughout for production by a thermo-forming process. In an embodiment, the member is formed of polypropylene.

Disclosed herein are blade geometries used to improve the structure of the blades and reduce audible noise when they are spinning Some aspects include: varying the radial angles between the blades which spreads the blade-pass frequency so it will not sound like a pure tone which is easier for the ear to pick out than white noise; adjusting the angle of the blade rake, which is an angle back along the axis of rotation, and the weight of the tip ring so that centrifugal forces balance wind thrust forces in the wind direction to keep the rake constant without excessively stiff and heavy blades; and blade sweep, which is a curve of the blade from the hub to the tip in the plane of rotation.

Referring to FIG. 8A, a turbine may be indicated generally therein at 108 with a hub 802, a plurality of circumaxially spaced blades, shown at 804, 804 and an annular ring 808 interconnecting the blade tips. The blades may be narrow, radially outwardly elongated and configured to respond to wind pressure and provide a torque in one direction. Each blade may have a root portion connected with and supported by the hub 802 and a remote tip portion connected with the ring 808. The blade tips may be displaced forwardly as a result of centerlines 810, 810, which curve gradually forwardly from their root portions to their tip portions to provide a forward blade sweep. Alternatively, the blades may have linear centerlines angularly arranged to provide a forward sweep. Preferably, the blades may have arcuate centerlines as shown with constant angles of curvature selected to cooperate with centrifugal force to provide insignificant blade movement at operating speeds. As shown, the blades 804, 804 may have tip displacements of approximately nine degrees, although tip displacements in the range one tenth of one degree to twenty degrees are contemplated.

The annular tip ring 808 interconnecting the blade tips, in addition to enhancing the generation of centrifugal force, tends to minimize vortices adjacent the blade tips and as a result noise generation is reduced and turbine performance enhanced. Twisting of the long narrow blades about their centerlines may also be reduced by the ring 808.

Referring to FIG. 8B, a turbine 108b that may have a hub 802b, blades 804b, 804b and an end ring 808b is illustrated. As will be obvious from an inspection of the drawing, the blades 804b, 804b may have a rake profile with their tip portions displaced rearwardly, or downwind, in relation to their root portions. The blades may also have linear centerlines 804b, 804b in FIG. 8B but gradually curved centerlines as at 810 in FIG. 8A may be contemplated as well as blades having only portions 812, 812 near their tips curved rearwardly as in FIG. 8D. In embodiments, the longitudinal centerline of each blade may have a constant rate of curvature from its root to its tip portion. Mass may be added at the tips of the blades to increase the centrifugal force generated during rotation and urge the blades radially in a direction opposite the direction of rotation and toward a linear centerline condition or urge the blades axially in a direction opposite the direction of wind flow. For example, the annular ring 808 may add mass. The longitudinal curvature of the blades and the tip mass may be selected in relation to centrifugal force such that centrifugal and wind generated forces balance and radial movement of the blade tips relative to the hub is insignificant at operating speeds of the turbine. In some embodiments, the angular displacement of each blade tip portion from the hub center through the point of attachment of the blade to the hub may fall in the range of one tenth of one degree to twenty degrees or may be approximately nine degrees.

Irrespective of the precise configuration, the displacement of each blade tip portion relative to its root portion may fall in the range of one degree to fifteen degrees and, preferably, the displacement may be approximately five degrees.

Referring to FIG. 9 turbine 108b may have a hub 802b, blades 804b, 804b, and an end ring 808b. The blades 804b, 804b may have any of the configurations described above but the circumaxial spacing thereof may be unequal. As shown, the blades 804b, 804b may have gradually curving centerlines 810, 810 in a forward sweep configuration as described above and their tip portions are unequally spaced circumaxially, spacing progressing from seventy degrees to seventy four degrees for the five blades shown. The root spacing may be equal in FIG. 9 but the tip spacing may be unequal, but it will be obvious that unequal spacing may be provided at both root and tip portions of the blades. Substantial reduction in noise generation may be achieved with the configuration shown.

As is described hereinabove, the wind turbine may include an impeller hub, which is mounted for rotation about an axis, and which supports a plurality of radially-extending, wind-responsive impeller blades. The blades may be connected with and supported by the hub on a root end of the blade. The blades are configured such that wind impinging thereon results in a substantial aggregate torque rotating the blades and hub in one direction.

The impeller blades may be manufactured by injection molding. In embodiments, the blades may be injection molded out of plastic. The blade may be injection molded with connection features at the blade root that enable mating with the impeller hub. For example, the features may enable fastening via an interference fit, a friction fit, a ball and socket, a zipper, a snap fit, a threaded fit, a hook and loop, an eyelet, a clip, a slot fit, a tab fit, and the like.

In embodiments, each impeller blade may be made in an identical mold. However, it should be understood that not all impeller blades mounted to a single impeller hub must be identical.

In embodiments, the impeller hub may also be injection molded. For example, the hub may be molded with a complementary feature to enable impeller blade mating. The impeller hub may also be injection molded to enable attachment to a generator shaft.

An imbalanced impeller would cause the tower to shake and cause excessive wear on the generator rotating support members. In an embodiment, weights may be added to the hub during or after injection molding in order to balance the impeller assembly. For example, the weights may be added during the final assembly. In an embodiment, the hub may have a feature for mounting balancing weights to balance the rotating masses about the rotational axis. The impeller hub may have features 5808, as seen in FIG. 58, through which a bolt may be mounted to serve as either the weight itself or to bolt something heavier. In embodiments, the features 5808 may be formed from plastic. The bolts may be through bolts with nuts on the opposite side or they may self tap into the features 5808. The features 5808 may be blind cylindrical cavities that do not go through. In an embodiment, the rotating support member may be a pair of wheels on a yoke that is affixed to each corner post. For embodiments of the tower with three corner posts, there may be six total wheels. The platform may have a rail that rests on the six wheels allowing the entire platform to rotate. In some embodiments, one wheel at each corner post could be used, such as if stronger wheel rotating support members were used.

Referring to FIGS. 57, 58, and 59, a plurality of injection molded impeller blades 5708 may be attached to an impeller hub 5800, which may also be injection molded, to form the final impeller blade assembly 5900. For example, a connection feature 5702 at the blade root (shown enlarged in FIG. 57B) may slide into a mating slot 5802 or otherwise connect with a complementary hub connection feature. FIG. 59B is an enlargement of an embodiment where the blade root connection features 5802 are mated with the mating slots 5802 of the impeller hub. The blade 5708 may then be secured, such as by being bolted in place. In embodiments, the blades may not be evenly spaced about the hub. In embodiments, the blades may be disposed in an angular relationship to the hub.

The impeller blade assembly may be adapted to attach to the generator shaft via the hub. In some embodiments, the impeller hub mounts to an adaptor hub on the generator shaft. The impeller hub may secure to the adaptor hub via a fastener, such as a nut, in an opening 5804 of the impeller hub that aligns with an opening on the adaptor hub.

Alternatively, the impeller hub may first be attached, and then the impeller blades may be attached to the impeller hub thereto. In some embodiments, the entire impeller blade assembly may be injection molded as a single unit.

In an embodiment, a nose cone, or other cover for the upwind side of the hub, may be injection molded. In an embodiment, the cover may be a blunt-nose curved axisymmetric shape. In another embodiment, the cover may be a dome-shaped nose cone that attaches to the front of the hub, obscuring the blade attachment to the hub. In yet another embodiment, the cover may be a bullet shaped nose cone. In some embodiments, the nose cone feature may be integrated into the hub, rather than being a separate part.

For example and without limitation, a sample process for assembling the impeller blade assembly is described. In the example, five blades made from the same blade mold are each connected to a hub as described herein and secured. Continuing with the example, the five-bladed impeller assembly is balanced. After balancing, the blades are removed and the separate parts are transported to the site of the wind turbine where the impeller assembly is identically reassembled and installed on a generator without changing the impeller balance that was performed previously.

Still continuing with the example, a nose cone may be attached. While many different attachment mechanisms may be utilized such as any of the fit mechanisms described above for impeller blade and impeller hub connection, the nose cone attachment in this example is a single bolt through the center of the nose cone to a tapped hole in the end of the generator shaft and nose cone tabs that mate into the hub. In embodiments, a sealant, epoxy or adhesive may be used to secure all bolts and connections in the final assembly. For example, LOCTITE® may be used.

In embodiments, assembly may include closed-cell foam being injected into air cavities of the impeller blade assembly, such as the nose cone, to prevent ice build up inside that would imbalance the blade. Injection of the closed-cell foam is done in a way that still allows the impeller to be disassembled for transport.

In an embodiment, the injection molded impeller blade may be hollow. In other embodiments, the impeller blades are solid.

In embodiments, the material used for injection molding may be glass-fiber filled plastic, such as glass-filled PPA, glass-filled nylon, and the like. In embodiments, the plastic used for injection molding may be carbon-fiber filled.

In an embodiment, the process for injection molding the wind turbine impeller blades may be controlled by a computer. The computer may receive sensor data from sensors mounted along the injection molding line. The sensors may be configured to report back a sensor output, such as any one of mold temperature, melt temperature, injection pressure, packing pressure, warping, and the like. The computer may modify the injection molding process based on the feedback received from one or more sensors reporting one or more sensor outputs.

In an embodiment, there may be three separate mold tools to form the blade, hub and nose cone of the assembly. The blade mold may include multiple plastic injection gates with hot runners, movable baffles that direct the flow at specific times, and a gas assist to make the root of the blade hollow to reduce warping and bulk plastic cost. The process for timing of gate opening/closing and baffle moving, temperatures at various places/times, and pressures at various places/times may be controlled by the computer.

Disclosed herein are stator vanes as airfoil-shaped coverings over structural support struts that are shaped to straighten the swirling airflow discharged downstream from the turbine blades to increase performance. Also disclosed is the use of steel as structural struts, struts as parallel offset metallic members to fit within optimum airfoil shapes, thermoplastic as the material for the airfoil-shaped coverings, cambered airfoils, extruded airfoils, and a single hard attachment point or friction attachment of the airfoil to the strut to accommodate differing thermal expansion of the two materials.

FIGS. 10B, 11B, and 11C illustrate an elongated sheath 1008 in the shape of an airfoil which may form an air-directing vane. As best illustrated in FIG. 11A the sheath 1008 has a number of integral strengthening members which may extend throughout its length within its interior cavity together with spaced apart elongated and parallel cylindrical openings 1112, 1112 which may slidably receive the aforementioned parallel tubular members 1012, 1012. An open channel 1114 extending between the two cylindrical openings 1112, 1112 may receive the transverse truss members 1102, 1102 of the structural member 1108. The sheath may also be provided with a camber, which together with the axial offset of the structural members results in an optimum airfoil configuration.

As will be apparent, the sheaths 1008, 1008 and the structural members 1108, 1108 may be readily assembled in a relative sliding operation. The sheaths 1008, 1008 and structural members 1108, 1108 may be maintained in their assembled relationship merely with the aid of friction or, alternatively, a single point of positive attachment may be provided as with a bolt 1118 in FIG. 11B. The bolt 1118 may penetrate the sheath and connect with the structural member 1012. Thus, thermal expansion and contraction of the sheath relative to the structural member is accommodated. Further in accommodation of thermal expansion, the sheath 1008 may be spaced slightly in a longitudinal direction from the hub 802 as illustrated at 1120 in FIG. 11C.

The structural members 1108, 1108 may take the form of trusses with a pair of elongated spaced apart parallel tubular members 1012, 1012 extending longitudinally and connected by transverse truss members 1102, 1102, FIGS. 10A, 11A, and 11C. The tubular structural members 1012, 1012 may be spaced apart axially as illustrated in FIG. 11A with the turbine axis depicted by broken line 1104. The members 1012, 1012 may also be offset axially as illustrated by the relationship between the axis line 1104 and the broken centerline 1108 of the tubular members, the lines 1104 and 1108 being angularly displaced as illustrated at 1110 in FIG. 11A. The structural members 1108, 1108 may be of metallic construction, and the specific material may vary but is preferably galvanized steel.

Disclosed herein is a sealing between independently rotating accelerators that are vertically stacked. Also disclosed is a horizontal-axis wind turbine with a ring connecting the blade tips and a variety of sealing geometries between the blade tip ring and a surrounding stationary ring (e.g., shroud), the primary sealing method being a labyrinth seal on one or both axial sides of the passageway between the blade ring and the stationary ring. Referring to FIG. 12, a schematic vertical section through a wind turbine is depicted. In an embodiment, the turbine blades 804 may be provided with an annular shroud. A portion 1202 of the vertical section may depict a sealing means. Details about the sealing means and the relationship of the shroud and the annular ring 808 will be described in conjunction with FIG. 13. The seal is provided for restricting the flow of air between the blade tip ring and the stationary ring thereabout and thereby directing maximum flow through the blades.

Referring to FIG. 13, an enlarged view of the portion 1202 is depicted. In an embodiment, the annular ring 808 may be adjacent to the annular shroud 120. Further, the annular ring 808 may be stationary. It will be evident to a person skilled in the art that enhanced blade performance may be achieved with a minimal loss of airflow radially outwardly about the turbine as might occur between the annular shroud 120 and the annular ring 808. Accordingly, a sealing means may be provided and may take the form of labyrinth seals at 602. The seals 602 may minimize the loss of airflow between the annular shroud 120 and the annular ring 808 with the air instead passing through or otherwise being directed to the turbine blades 804 as desired. In an embodiment, the blade edges may be at least partially enclosed through 360 degrees. The turbine blades, the hub, and the annular ring about the blades may be integrally molded in a one-piece plastic molded process, such as by an injection molding process.

A vertically sectioned cylindrical accelerator for mounting pairs of wind turbines respectively on opposite sides thereof may have a covering of twin-sheet thermoformed plastic panels which are smooth on the outside but carry a multiplicity of small cone-shaped projections on their interior surface. The panels may be mounted on a structural member to enable free expansion and contraction with variation in ambient temperature. For example, the panels may be secured using a single central bolt, a combination of a single central bolt, a plurality of bolts, a mechanism that allows the panel to move relative to the underlying truss structure to allow for thermal expansion differences between the skin panel and the truss structure, and a combination of one or more bolts and the mechanism. The panels may be manufactured in a twin-sheet thermoforming operation wherein one sheet is maintained with a smooth surface and the second sheet is provided with the cone-shaped projections, the two sheets being fused together to form an integral panel of lightweight and high strength characteristics.

Referring to FIG. 14, a plan view of a single panel 1402 is depicted. The panel 1402 may be configured as a large monolithic substantially rectangular panel. The panel 1402 may be approximately eight and one half (8.5) feet long and five (5) feet wide. Further, overall thickness of the panel 1402 may be approximately one and one fourth (1.25) inches. In an embodiment, an exterior surface 1404 of the panel 1402 may be smooth and continuous for uninterrupted wind flow thereover.

Now referring to FIG. 15, a fragmentary enlarged side view of the panel 1402 is depicted. In an embodiment, an interior surface of the panel 1402 may include a multiplicity of small strengthening projections 1508, 1508. The projections 1508, 1508 may take the form of a plurality of small cones. In an exemplary embodiment, the panel 1402 may be manufactured with a slightly greater curvature than in the installed condition.

Referring to FIG. 16, an exploded side view of the panel 1402 and associated structural members prior to mounting the panel 1402 on the members is depicted. The panel 1402 may be shown prior to installation with a slight excess curvature. The panel 1402 may receive a structural member 1602 by means of a notch 1608. Further, at a central location, the panel 1402 may be provided with another notch for receiving another structural member 1604 of the accelerator 104. More details about the another notch and the another structural member 1604 will be explained in conjunction with FIG. 17.

Referring to FIG. 17, a fragmentary exploded and enlarged side view illustrating the panel 1402 and structural members 1602, 1604 is depicted. Further, the panel 1402 may include a notch 1702. Centrally located in the notch 1702 may be a single through opening 1704. The opening 1704 may be provided with a grommet 1708 for receiving a bolt 1710. The bolt 1710 may be the only positive connection between the panel 1402 and the structural members 1602, 1604 of the accelerator 104. Further, the notch 1702 may be provided with a few projections 1712.

Now referring to FIG. 18, a further enlarged view in perspective and showing edge portions of a pair of panels 1402 is depicted. In an embodiment, six small spaced projections 1712 on walls of the notch 1702 may provide for a press fit of the structural member 1604 in the notch 1702. In a preferred embodiment, notches 1714, 1608 may also be provided at opposite ends of the panel 1402 for receiving structural members 1602, 1602. Further, the structural members 1602, 1602 may position the ends of the panel 1402 precisely against a flexing force of the latter, a left hand edge portion of an adjacent panel being inserted between the structural member 1602 and the base of the notch in the right hand notch 1607 which may be substantially deeper than the left hand notch 1714.

Referring to FIG. 19, a side view similar to FIG. 18 but showing the panel 1402 partially attached to a structural member is depicted. In an embodiment, the structure member 1602 of the panel 1402 may be received by the notch 1714.

Referring to FIG. 20, a fragmentary enlarged exploded side view similar to FIGS. 16 and 19 showing the panel 1402 partially attached to the structural member 1602 is depicted. As mentioned herein, the notch 1702 may be single through the opening 1704. Further, the panel 1402 may include the projections 1712.

Referring to FIG. 21, an enlarged vertical cross sectional view of the panel 1402 taken through a central portion thereof is depicted.

FIGS. 19, 20 and 21 show the panel 1402 in position on and supported by the structural member 1604.

Now referring to FIG. 22, a perspective view in cross section taken through a central portion of the panel 1402 is depicted. Further, FIG. 23 depicts an enlarged cross sectional view through an overlapping vertical joint between panels. As illustrated in FIGS. 22 and 23, the overlapping vertical edge portions 2302 of the panel 1402 may be shown with the edge portion 2302 provided with a small boss 128 on its interior surface. The boss 128 may be engaged by an anti-rattle spring clip 2304 at a central portion of the latter with end portions of the clip entered in openings 2308, 2310 respectively in end portions of the panels adjacent the edge portions 2302. Further, the spring clip 2304 may be maintained in a slightly flexed condition to ensure a tight fit between the panel edge portions 2302 and may thus prevent intermittent airflow inwardly and resulting rattle.

Referring to FIG. 24, an enlarged sectional view of the panel 1402 and its mounting means are illustrated. In an embodiment, a panel 2402 may extend between panel edge portions 2402a and 2302a, overlapping the edge portion 2302a and in turn may be overlapped by the edge portion 2402a. Further, a rivet 2404 or other connector may be employed to connect the panel 2402 to the edge portion 2402a and to one end of a spring clip 2404; the latter may have its opposite end connected to the panel 2402 at a central portion by a bolt 2410 and a nut 2412. As will be apparent, the bolt 2410 may be tightened to draw the panel 2402 and the clip 2404 toward engagement and to urge the end portion of the panel 2402 against the edge portion 2302a thus completing a tight closure of all joints between the panel 2402 and vertically adjacent panels 1402a, 1402a.

Disclosed herein is a twin thermoforming process used to fabricate the skin panels of the accelerator platform. Aspects of the panel geometry may be adapted to enhance strength, prevent rotation, allow for thermal expansion, and generate overlap regions between panels that allow for minimal disruption of the air flowing over the surface and the shedding of rainwater. Now referring to FIG. 25, a cross sectional view through an open thermoforming mold for the panels is depicted. Further, FIG. 26 depicts a fragmentary enlarged view through a portion of the mold of FIG. 25. Also, FIG. 27 depicts a portion of the mold with the mold closed. FIGS. 25-27 will be described herein together. In an embodiment, the mold may be employed in the manufacture of the panels 1402, 1402 and it will be noted that an upper mold half 2502 may have a gradually arcuate smooth lower surface 2504 for forming the exterior surface of a first sheet of thermoplastic 2508 which may be extruded or otherwise prepared. A lower mold half 2510 may have a multiplicity of small projections 2512, 2512 for forming cones on the lower surface of a second sheet of plastic 2514 and for fusing and forming the two sheets of plastic into a single integral panel 1402 of large monolithic unitary construction in a rectangular or other configuration. This method of molding may be known as “twin-sheet thermoforming” and may result in a panel 1402 of the highest possible strength to weight ratio. The presently preferred plastic may be high-density high-molecular weight polyethylene. In some embodiments, the inside of the twin-thermoformed skin panel structure may be filled with structural foam after the twin-thermoforming process to make it at least one of stiffer and stronger.

Disclosed herein is a method of forming a structural adhesive joint between two tubular members. Gluing with a structural adhesive, like bolting, is a method of joining steel components that can be done in the field without compromising corrosion protection already applied to the members to be joined. Properly engineered adhesive joints take advantage of the compliance of the adhesive to reduce stress concentrations in the joint and use less material than bolted flange couplings, reducing weight and cost of a structure with many joints such as a truss. This disclosure provides methods of achieving good adhesive joints between telescoped tubular components using a centering means to maintain the proper adhesive thickness and an adhesive injection means that is fast for field installation and results in complete filling of the adhesive chamber.

Referring to FIGS. 28 and 29, an adhesive joint construction indicated generally at 2800 may include telescopically assembled male and female members 2802 and 2804, which may be similar in cross sectional configuration but which are different in size so as to cooperatively define a narrow continuous open-end adhesive chamber 2808. The members 2802 and 2804 may be both tubular with circular cross sections as shown, but as mentioned above, a wide variety of types of tubular and other male and female members may benefit from the teaching of the present disclosure. As mentioned above, it may be most important to maintain uniform thickness of the adhesive throughout the chamber 2808 without pockets or voids in order to provide an efficient and low cost joint of high structural integrity and light weight.

The male and female members may be designed to provide adhesive chamber 2808 of uniform width throughout when the members may be telescopically assembled and small locating pins 2810, 2810 may thereafter be employed to fix the relative positions of the members and precisely establish the width of the adhesive chamber 2808. At least one pin 2810 may be provided and as shown, four (4) equally circumaxially spaced pins 2810, 2810 may be inserted into the adhesive chamber 2808 through its open end to positively fix the position of the members and the width of the chamber 2808. The pins 2810, 2810 may be inserted under pressure as with a pneumatic gun and may thus serve as a self-fixturing function for the joint.

Referring to FIGS. 29 and 36, a series of small notches 2902, 2902 may be provided in equally circumaxial spaced relationship around the mouth of the female member 2804. Each notch 2902 may have a shallow chamber 3602 at its inner end which may be adapted to direct a locating pin 2810 into an adhesive chamber in pressure engagement with the contiguous surfaces of the male and female members 2802, 2804.

Alternatively, locating pins such as 3202, 3202 shown in FIG. 32 may be employed as centering means and may be positioned in the mouth of the female member 2804 prior to assembly of the same with the male member 2802. A connecting loop 3204 may facilitate handling the pair of the locating pins 3202, 3202.

Referring to FIG. 33, a second alternative embodiment of centering means is shown with integral ribs 3302, 3302 formed in circumaxially spaced relationship on the interior surface of a rectangular tubular member 3304 with two (2) ribs 3302, 3302 on one side of the member 3304.

Still further, short centering means 3702 may include a single annular element or a number of individual ribs on the interior surface of the female member 2804 spaced inwardly from the mouth of the member as shown in FIG. 37. The annular element or ribs 3702 may serve as auxiliary centering means and may engage and center the free end of a male member 2802 as it may reach the end of its travel during assembly of the male and female members. The annular element or ribs 3702 may be employed with any of the foregoing centering means.

With the adhesive chamber 2808 properly sized and the members 2802 and 2804 secured in fixed positions by the pins 2810, 2810, a distributing device 2814 may be positioned about open end 2812 of the adhesive chamber 2808, and as shown in FIGS. 34 and 38 encloses and may have an inlet port 2902 which may communicate with the same for the introduction of an adhesive under pressure. Various adhesives may be employed but LOCTITE H8600 may be preferred in an illustrative embodiment for joining the galvanized structural steel employed in wind turbine tower construction. A relatively low viscosity adhesive may be preferred for rapid insertion in a high production environment. A uniform adhesive thickness less than fifty thousandths of an inch may be found to provide the high strength low weight results desired with galvanized structural steel.

As mentioned above, the use of open cell foam seals may accommodate an adhesive filling procedure based on pressure control and termination resulting in a completely filled adhesive chamber. It should also be noted that the distributing device 2814 may serve independently as a centering means avoiding the need for substantially all other centering means.

As mentioned, the prevention of voids in the adhesive may also be important and a small open cell foam insert 2818, FIGS. 30 and 37, captured and compressed between an annular shoulder 2820 on the interior wall of the female member 2804, and the inner end of the male member 2802 may prevent the entrapment of air and resulting pockets or voids. The insert may be perforate to air and may readily allow the same to pass but may serve as an effective barrier to adhesive.

Referring now to FIG. 35, it may be observed that three (3) elongated structural members 3502, 3502 form a closed loop subassembly indicated generally at 3504, which may be a part of a truss type wind turbine tower. Employing the teaching of the present method, the members 3502, 3502 may be assembled as shown with their end portions entered loosely in cups 3508, 3508, which form a part of connecting or joint members 3510, 3510. Locating pins such as 2810, 2810, not shown, may then be inserted circumaxially about the ends of the members 3502, 3502 into adhesive chambers within the cups 3508, 3508 in a self-fixturing operation. This may be followed by positioning of adhesive distributing devices about the joints and the introduction of adhesive to fill the adhesive chambers thus completing the subassembly.

Disclosed are flange geometries for welding to the end of tubes that result in the best strength per weight of the flange plus tube system. By morphing from a thin-walled tube to a flange in a roughly elliptical manner, stress concentrations may be reduced resulting in at least one of thinner tubes, lighter flanges, or a combination thereof. Because galvanizing steel cannot be done in the field, it is necessary to have another joining means such as bolted flanges for final construction at the site of the wind turbine. Thus, for a given strength of tower, the use of steel may be economized. Referring to FIG. 39, a first embodiment of the present invention is indicated generally at 3900 and may include a radial flange 3902 and an axial boss 3904 projecting axially there from. A corner area at the junction of the flange and boss may be indicated generally at C with adjacent area B extending from the corner region along the neck and toward the free end of the boss. A second and substantially smaller area D adjacent the corner area (on its opposite side) may extend along the flange 3902 toward its free end. A through opening or axial bore 3912 may extend from the free end of the boss to a planar surface 3914 on the flange which may reside in a radial plane. The corner or junction E between the planar surface 3914 and internal annular surface 3912 of the boss 3904 may be defined by a convex curve E also on a relatively small radius.

As mentioned above, the external surfaces of the unit at B, C and D may be bounded by two points or imaginary annular lines 3908, 3910 respectively on the axial surface of the boss and the radial surface of the flange. The former line may be substantially farther from the corner than the latter as indicated by the dimensions F, G. As will be apparent on inspection, the external surface 3912 may curve gradually adjacent the boundary line 3908 and substantially more rapidly adjacent the boundary line 3910 on the flange. At each end, however, the arcuate surface may blend smoothly in transition to a linear surface on the opposite side of the boundary line. As stated above, the curve may also be regarded as having a gently changing slope adjacent the boss and a more sharply changing slope adjacent the flange. Still further, the external surface 3912 may be viewed as defined by at least three, and preferably an infinite number of discrete radii. In any event, the portions of the surface may blend together to form a continuously varying smooth arcuate surface with the surface of the smallest radius on the flange 3902. Preferably the surfaces B, C and D taken in the aggregate, at least approximately follow the contour of the external surface of a quadrant of an ellipse, shown in broken line at 3916.

As mentioned above, the enhanced thickness of the wall of the coupling unit may be a second important feature of the present invention. As will be obvious from inspection of the drawings, the wall thickness of the unit may proceed along the neck of the boss toward the flange increasing through the regions B and (and remaining substantially constant in outward progression along the flange from C to the outer end of the flange.

FIG. 40 shows a second embodiment of the invention in the form of a coupling unit 4002 having a flange 4004 and an axial boss 4008. The external surface of the unit at its corner region and adjacent areas may be identical with those of the coupling of FIG. 39. The internal surface of the unit, however, may vary substantially from that of the FIG. 39 coupling and instead may be substantially identical with the external surface. As will be obvious, this may result in a slight reduction of the thickness of the coupling wall but the unit may nevertheless be found to have excellent strength characteristics and may be a lightweight construction. A third embodiment of the coupling unit of the present invention may be indicated generally at 4100 in FIG. 41. The unit may include a flange 4108 and a boss 4102 with an external corner area C with a relatively small radius of curvature similar to that of conventional coupling units. The internal surface of the unit at 4104, however, may be substantially identical with the external surface B, C, and D in FIG. 39 and with the internal and external surfaces in FIG. 40. This may entail a substantial radial inward bulge of the inner surface, which may be acceptable in certain applications. Wall thickness may be superior in this embodiment to both the FIG. 39 and FIG. 40 embodiments.

FIG. 42 illustrates a structural use of the improved coupling of the present invention in a wind turbine tower or the like having a plurality of elongated tubular structural members 4204, 4204 interconnected by coupling units 3900, 3900 shown in enlarged fragmentary section in FIG. 43. As illustrated in FIG. 43, each of the flanges 3902, 3902 of mating coupling units 3900, 3900 may be provided with an annular series of axial openings 4010, 4010 which receive bolts 4302, 4302 connecting the units together.

Referring to FIG. 44, an alternative means of connection is provided in the form of a clamp member 4402, which may surround the flanges 3902, 3902 and may in turn be interconnected by bolts 4404, 4404 whereby to clamp and firmly hold the flanges in engagement.

FIG. 45 illustrates the use of a single coupling unit as a mounting support for a large generally vertical elongated base member of a wind turbine tower or the like. The unit may have a configuration substantially identical with the FIG. 39 unit and may be attached to a foundation by a plurality of bolts as illustrated. From the foregoing, it will be apparent that design improvements have been made which may initially seem to be minor in nature, but which in the aggregate are nevertheless found to substantially enhance the strength and integrity of the units while simultaneously reducing the weight and the amount of material consumed in manufacture of the improved coupling units.

FIG. 46 illustrates an alternative embodiment of the invention with improved foundation systems providing a higher degree of structural integrity and superior stability for the tower and its wind turbines even in hurricane conditions. Referring particularly to FIG. 46, lower end portions 4602, 4602 of three (3) elongated tubular members forming an outrigger may be shown connected by flanges 4604, 4604 with short tubular connecting tubes 4608, 4608. The connecting tubes may open at their lower ends and may receive upper end portions of tubular metallic inner members 4610, 4610 of micro piles 4612, 4612. Further, external nuts 4614, 4614, one shown, may cooperate with nuts internally of the connecting tubes together with rotating support member plates in affecting connections between the outriggers 4602, 4602 and the tubular inner members 4610, 4610 of the micro piles.

A manifold 4618, which may preferably be of precast concrete, may have three (3) openings 4620, 4620 for receiving the inner members 4610, 4610 of the micro piles. A hardenable medium 4622 may fill the gaps between the walls of the openings 4620, 4620 and the tubular micro pile members 4610, 4610, the former being somewhat larger in diameter than the latter.

As will be apparent from the forgoing, the upper end portions of the tubular members 4610, 4610 of the micro piles may be maintained in desired predetermined positions by means of the manifold 4618, and as will be described herein below, the manifold 4618 may also serve as a guide during the formation of the micro piles whereby to establish desired predetermined angular relationships of the micro piles.

Referring to FIG. 47, a manifold 4700 is shown for establishing connection of tubular upper end portions 4702, 4702 of micro piles 4704, 4704. The manifold 4700 may also be constructed of precast concrete and may have three through openings 4708, 4708, two shown, for receiving the tubular inner members 4702, 4702 of the micro piles. A hardenable medium 4710, 4710 may fill gaps between the tubular members 4702, 4702 and the walls of the openings 4708, 4708. At upper end portions, the members 4702, 4702 may be connected with a manifold type bracket 4712, which has three (3) flanges 4714, 4714, two shown. The flanges 4714, 4714 may have openings for receiving the members 4702, 4702 and may be associated with upper and lower nuts 4718, 4720 that secure the members 4702, 4702 in the openings in the flanges 4714, 4714. At its upper end, the manifold type bracket 4712 may carry a large flange 4722 for connection with a main vertical structural member of a wind turbine tower. An associated truss member may be connected with the bracket 4724.

The micro piles 4612, 4612 and 4704, 4704 may extend a substantial distance downwardly into the earth and may be between 20 and 50 feet in length, preferably approximately 30 feet long for both the outriggers and the main structural members of the tower. Further, the micro piles may extend in a “splayed” relationship with each other, FIG. 48, for maximum effectiveness in both compression and tension. The angular relationship of the micro piles with respect to the centerlines of their supported members may vary, but it is preferred to maintain a displacement of approximately 3 degrees from the centerlines of the outriggers and a displacement of approximately 10 degrees from the centerlines of the structural members of the towers.

Referring now to FIG. 48, the template function of the manifolds 4618, 4700 is illustrated subsequent to the drilling operation and the injection of concrete through a tube such as 4702a. The tube 4702a may be entered in an opening 4620a and may be maintained in position on completion of drilling and concrete injection by means of one or more small inserts 4802, 4802 positioned in the opening 4620a. A first insert 4802 is shown in the opening 4620a in FIG. 48, and a second insert 4802 is shown above the upper end of the tube 4702a. As will be apparent, the inserts 4802, 4802 may serve to maintain the tubular member 4702a in a desired angular position when drilling and formation of the micro pile is complete with the concrete remaining in an unhardened condition. The inserts 4802, 4602 may be retained in the opening 4620a during grouting of the opening 4620a with hardenable medium and may insure precise final positioning of the upper ends of the members 4702a, 4702a for connection with their respective supported members.

Disclosed herein is a method of manufacturing the flange of the coupling unit described above. As described previously herein, the coupling unit includes a radial flange and an axial boss with an axial bore, and is adapted to couple tubular members that form the structural components of the tower for mounting wind turbines.

Alloyed steels may be used to manufacture the flange. The flange may then be welded to a tube without becoming brittle in the heat-affected zone. The alloyed steel may be compatible with the galvanizing process without any other treatment (e.g. annealing).

The flange material may begin as hot rolled bar stock or a high-strength, low-alloy (HSLA) steel plate that may be hot-formed to a near net shape resembling the finished flange, and then machine-finished to the final size. The flange raw material may be steel utilizing alloying elements rather than carbon to attain the desired grain size and structure in the final product. Grain structure and size may affect the mechanical properties of the flange, and may be controlled in part by the alloying elements and in part by the manufacturing process. Using the alloyed steel enables welding of the flange to a tube without heat treatment of the weld zone. In embodiments, alloying elements of steel may be selected to reduce grain growth during reheating, restrict zinc alloy growth during galvanizing, and to have high strength without heat treatment.

In an embodiment, the hot rolled bar may be a fine grain hot-rolled bar that may be cut to a pre-determined length and heated to form a slug. The slug may then be moved to a die which may close around the hot bar forming it into a shape resembling the finished flange. The formed slug may then be cooled and machined to the net shape.

In an embodiment, the HSLA plate may be cut to a pre-determined size and placed into a die which draws the steel to a shape resembling the finished flange. The formed steel may then be cooled and machined to net shape.

In an embodiment of the process, a steel slug may be hot rolled into an approximate cylindrical shape, heated, and forged with one or more steps to form it into a shape approximating the shape of the flange as described herein. Forging may include striking the material while it is hot. In another embodiment of the process, a steel slug may be hot rolled into a flat piece of steel, cut into an approximate cylindrical shape, heated, and forged with one or more steps to form it into a shape approximating the shape of a flange as described herein.

In any event, the material may then be cooled and the inside and outside surfaces of the flange may be machined to their final shape. The flange may then be welded to the tubular member.

The flange material may comprise a carbon content less than 0.3%. The flange material may comprise a carbon equivalent defined by an equation, such as the American Welding Society (AWS) equation or any other applicable equation. For example, the AWS equation is as follows: CE=% C+((% Mn+% Si)/6)+((% Cr+% Mo+% V)/5)+((% Cu+% Ni)/15), less than 0.45%. The flange material may comprise an element to retard grain growth during heating above the austentizing temperature, such as a temperature of about 1000 degrees Fahrenheit. The flange material may comprise at least one of titanium, niobium, ruthenium, vanadium, zirconium, molybdenum, or other rare earth elements, metals, transition metals, or combinations thereof.

The flange material may be of a fine grain with a grain size (G) of 12 or smaller, as measured using ASTM E112. In embodiments, the grain size is substantially about 7. It should be understood that the flange material is not limited to a particular grain size.

The flange material may include austenite dispersed in a ferrite microstructure, pearlite dispersed in a ferrite microstructure, carbide precipitates in a ferrite microstructure, nitride precipitates in a ferrite microstructure, or the like.

The weld may be a multipass metal inert gas (MIG) weld. The weld may be an inside tungsten inert gas (TIG) pass weld. After welding, the assembly may be galvanized.

Disclosed herein is a tower and wind turbine supporting structure which at least partially envelops the tower at an elevated position for enhanced wind velocity. The tower includes a plurality of horizontally spaced apart vertically extending narrow elongated and lightweight members and a plurality of shorter narrow lightweight interconnecting cross members extending between the vertical members and cooperating therewith to form a massive monolithic structure having a vertical dimension of at least thirty five (35) feet. The exterior cross sectional configuration and dimensions of the tower from its base to the area of attachment of the wind turbine supporting structure may be less than that of the adjacent interior cross sectional surfaces of the wind turbine supporting structure. At least one power operated lifting device may be mounted substantially at the top of the tower and have at least one lift line extending downwardly therefrom. A plurality of diagonally extending outriggers may be adapted to be attached to the tower after the turbine and supporting structure has been positioned at the base of the tower, raised to its respective operating position by said lifting device and secured in place. The outriggers may be spaced apart horizontally about the base of the tower and may each be of narrow elongated and lightweight but longitudinally rigid construction, each outrigger having its upper end portion connected to the tower in supporting relationship therewith and its lower end portion disposed in horizontally spaced relationship with the tower at least approximately at ground level. The supporting structure may include a foundation system supporting each vertical structural member of the tower and each outrigger at its lower end portion. The wind turbines and their supporting structures may be substantially completely manufactured on site about the base of the tower. Alternatively, the wind turbines and their supporting structures may be manufactured off-site in sections, and the sections may be transported to the site and assembled sequentially about the tower base and thereafter raised and secured in position. The sections may be no larger than that allowed for truck transport.

Referring to FIG. 49, a tower for mounting wind turbines and their supporting structures is indicated generally at 4900 with the tower proper at 4902, supporting structures at 504, 504 and turbines at 108,108. The illustrative tower 4902 shown may have a height A of two hundred (200) feet. As illustrated in FIG. 50, the tower 4902 may include a plurality of narrow elongated and lightweight vertically extending longitudinal members 4904, 4904, preferably tubular, and a plurality of shorter narrow lightweight interconnecting cross members 5012, 5012. The cross members 5012, 5012 may be tubular or triangular in cross section in a truss structure. The members 5012, 5012 may extend between the members 4904, 4904 and may cooperate therewith to form a massive monolithic structure having a vertical dimension of at least fifty (50) feet. The cross section and other structural characteristics of the tower may vary but in all cases the cross sectional dimensions and configuration of the tower may from its base to the area of connection with the wind turbine supporting structures be at least partially uniform to permit raising of the wind turbines and their supporting structures thereabout. Tower 4902 may be a preferred triangular vertically uniform cross sectional configuration the short cross members 5012, 5012 extending diagonally between the vertical members 4904, 4904.

Mounted at or near the top of the tower or at its base may be a power operated lifting device 4908, which may be shown with a pair of depending lift lines 4912, 4912 respectively on opposite sides of the tower 4902 and may be connected with a wind turbine supporting structure 504 at the base of the tower.

The wind turbines 108, 108 and their supporting structures 504, 504 may vary widely in construction and may completely surround the tower 4902. It should also be noted that the supporting structures may be mounted for incremental rotation about the tower in adjusting the position of the turbines for optimum performance in response to change in the direction of wind flow.

Referring now to FIG. 56, a tower for mounting wind turbines and accelerator platforms is depicted. In this embodiment, the tower is a double-lattice, or truss-type, tower with diagonal support beams attached to the corner posts at the exact same vertical spacing as the spacing between the accelerators (also known as accelerator platforms) and wind turbines. The rotating support member attachment points that hold the rotating accelerator platforms to the tower may be located substantially at the same locations as the support brace intersections for maximum strength.

FIG. 56A depicts a top view of the tower. FIG. 56B depicts a section view where the section goes through a blade, along the inner diameter of an accelerator platform to a rotating support member on one corner post, straight to another corner post to another rotating support member, and along the inner diameter of the platform until it can go straight through the other turbine. FIG. 56 also depicts the wind turbines 5620 with an impeller 5618 that defines a swept area 5614.

The vertical spacing between rotating support member attachment points from one accelerator platform 5602 to the other may be the same as the spacing between the wind turbine impeller hubs 5604 and is shown as dimension h. The vertical spacing between the intersections of the cross braces 5612 and corner posts 5610 is shown as dimension d. The relationship between these vertical spacings may be described by the equation h=n*d where n is an integer. The cross bracing structure on the tower depicted in FIG. 56 is a so-called double lattice architecture where each cross brace 5612 in one direction crosses three cross braces 5612 in the other direction. In the case depicted in FIG. 56, the vertical spacing of the tower would be described by the equation h=2*d. It should be understood that not all towers will be of a double lattice architecture. For example, in a single-lattice tower the cross braces 5612 would be a series of X's going up the tower where each cross brace 5612 intersects a single cross brace 5612 in the other direction. In this case, the vertical spacings of the tower would be described by the equation h=d.

In an embodiment, a lattice (truss-type) tower for wind turbine 5620 mounting may have two or more accelerator platforms 5602 attached to the tower such that they can rotate around the tower on rotating support members 5608 mounted on each corner post 5610. Each accelerator platform 5602 may have two horizontal-axis wind turbines 5620 on opposite sides and the accelerator platforms 5602 may be mounted on the tower in a vertical stacking arrangement. The lattice tower may have three or more corner posts 5610 with angled cross bracing 5612 between the corner posts 5610. The vertical spacing between the rotating support members from one platform 5602 to an adjacent platform 5602 may be an exact multiple of the vertical spacing between the intersection points between the cross braces 5612 and the corner posts 5610.

Each rotating support member 5608 may be located on the corner posts 5610 at substantially the same location as where the cross braces 5612 intersect the corner posts 5610. In the tower, the rotating support member location mounts may be substantially close to where the center line of a cross brace 5612 may intersect the outside of the corner post 5610. In an embodiment, at an intersection point there may be cross braces 5612 that go downwards and cross braces 5612 that go upwards. The downwards and upwards cross braces 5612 would not intersect the outside of the corner post 5610 at the same place. The rotating support members 5608 may be located at the higher of the two locations, i.e., the intersection of the centerline of the cross brace 5612 that goes downward from the intersection point.

The vertical location of the rotating support member attachment points may be within a pre-defined distance of where the cross braces 5612 intersect the corner posts 5610, where the pre-defined distance may be a percentage of the spacing between intersection points between the cross braces 5612 and the corner posts 5610.

In embodiment, each platform may be mounted to the tower on its own rotating support member 5608. The vertical spacing of rotating support members 5608 between adjacent accelerator platforms 5602 may be aligned with cross braces spacing. The rotating support members are aligned at cross brace intersection points.

In an embodiment, the vertical spacing between turbine axes may be greater than 1.25 the diameter of the turbines. The accelerators carrying the turbines may each define a passageway designed to capture and direct a stream of wind through an arcuate horizontal path to its associated wind turbine, each said passageway having an interior forwardly facing concave central portion viewed in cross-section which is generally parti-circular for wind impact, redirection horizontally and transfer to the turbine. There may be forwardly facing convex exposed opposite end portions at the mouth of the passageway viewed in cross-section each having a sharp substantially pointed radius of curvature for entry of the wind and direction of the same rearwardly toward the central portion of the passageway. The radii of said end portions may fall in the range of zero (0) to 0.25 the diameter of the turbines. Smooth transition portions may converge toward the central portion from the front end portions of each passageway. The radius of curvature of the end portions of the passageways falls in the neighborhood of zero (0) to 0.1 or approximately zero. The transition portions of said passageway may be linear. A unitary wind passageway may extend continuously in opposite directions and in a generally diverging arcuate path from a front portion of the accelerator to each of the turbines. Each wind passageway may extend arcuately from the front of the accelerator through approximately one hundred eighty degrees (180 degrees) in each direction to the wind turbines. Each of said wind passageways may generally be parti-circular viewed vertically and open radially outwardly substantially throughout its length between the wind turbines. The turbine inlets may provide a funnel like configuration transitioning air into the turbines. Each turbine may have a funnel like shape at its outlet to diffuse air from the turbine.

In embodiments, a winch at the bottom of the tower with cables running up over pulleys at the top of the tower may be used to lift the accelerator platforms 5602 to the mounting positions along the tower.

In an embodiment, when two or more accelerator platforms 5602 are mounted on a tower, each accelerator platform 5602 is mounted to the tower on its own rotating support members. The platforms 5602 may be connected together in a way that forces them to rotate together about a vertical Z axis, i.e., the platforms 5602 are linked together in such a way that they always point in substantially the same direction relative to rotation about the vertical Z axis (give or take a few degrees for tolerance), but all other degrees of freedom remain (translation in X, Y, and Z and rotation about X and Y). Thus, if one accelerator platform 5602 tries to rotate, it will cause all of the other accelerator platforms 5602 to rotate with it, however, no other significant forces other than rotation about the Z axis may act between the platforms. In this way, each platform 5602 carries its own weight on its own rotating support members 5608, and the platforms 5602 can translate in the horizontal plane relative to each other to allow for tolerances in how each platform 5602 rotates on its rotating support members 5608. In some embodiments, the rotating support members 5608 on each platform 5602 may allow movement, such as movement in the horizontal plane, to account for tolerances in the roundness of the platform.

In some embodiments, the freedom for accelerator platforms 5602 to move in the X-Y plane relative to each other may be restricted by a compliant spring-like means. The restriction is such that horizontal translation and angular misalignment (rotation about the Z axis) between adjacent platforms is possible but the further the platforms translate/rotate from the nominal relative position between platforms, the more force there is trying to pull them back to the nominal relative position/angle between platforms. In these embodiments there may be no substantial mechanical coupling that resists relative motion in the Z direction between platforms.

In an embodiment, the power cables carrying power from the generators attached to the wind turbines to the ground come up to the top of the tower and drop down the middle of the tower in the so-called twist section. The twist section enables the accelerator platforms to rotate at least a plurality of turns in either direction. In some embodiments, a plurality of generators for the tower may have their cables running down the center of the tower in the twist section. In embodiments, both power and communication wires to instrumentation and actuators on the rotating accelerator platforms may run down the center of the tower so they may also twist.

Disclosed herein is a lattice tower with substantially uniform cross section and outriggers that can be attached after the wind accelerating platforms have been raised into place, such as by using power operated lifting devices rigged to the tower, alleviating the need for a crane to install the parts of the wind turbine mounted up on the tower. Different truss geometries for the tower and outriggers may be possible. Also disclosed is the use of foundation members only where the vertical tower members reach the ground, and the use of micropile foundations as the discrete foundation members. The use of micropiles greatly reduces the amount of concrete use compared to pedestal-type foundations for conventional wind turbines.

Referring to FIG. 50, a plurality of longitudinally rigid outriggers may provide support in both tension and compression. As shown, three (3) outriggers 4910, 4910 may be provided and each outrigger 4910 may be of tubular metallic construction with three (3) longitudinally extending elongated members 5014, 5014 in a triangular configuration and a plurality of shorter tubular members 5018, 5018 interconnecting the longitudinal members. The outriggers 4910, 4910 may have their upper end portions connected in supporting relationship with the vertical longitudinally members of the tower; three (3) outriggers may be provided for the triangular tower 4902. Preferably, the connection of the outriggers with the tower may be effected at the point where at least one cross member 5012 may connect with a vertical member 4904. Further, the outriggers may have a length B in the range twenty (20} to one hundred (100) feet and, in the illustrative embodiment shown, the outriggers may have a length B of approximately fifty (50) feet. The outriggers may be at an angle with the vertical in the range of thirty (30) to eighty (80) degrees, the preferred angle may be approximately sixty (60) degrees.

At lower end portions, the outriggers 4910, 4910 may be provided with separate foundation members in the form of elongated members 4918, 4918 of composite metallic and concrete construction. As shown, the foundation members 4918, 4918 may take the form of micro piles of the type sold and installed by CON-TECH SYSTEMS LTD. of 8150 River Road, Delta, B.C. Canada V4G 1B5 under the trademarks SCHEBECK and TITAN and may extend downwardly into the earth at angles substantially the same as that of the members which they support. The length of the micro pile members may be in the range of twenty (20) to fifty (50) feet and in the illustrative embodiment shown, the outrigger foundation members 4918, 4918 may be approximately thirty (30) feet long.

When bedrock may be reasonably close to the surface, the foundation members 4918, 4918 may be supported by anchors 4914 embedded in the bedrock, one shown on the right hand member 4918 in FIG. 49. Foundation members 4920, 4920 for the vertical members 4904, 4904 of the tower 4902 may be preferably the same as those for the outriggers with the length of the members falling in the range of twenty (20) to fifty (50) feet. In the illustrative embodiment shown, the length of the members 4920, 4920 may be approximately thirty (30) feet and the members extend vertically, downwardly from the vertical members which they support.

Referring to FIG. 51 a fragmentary illustration in perspective of an erection apparatus connected with a tower to be erected is depicted. In an embodiment, a wind turbine tower or the like may be indicated at 5100 in position on the ground ready for erection. The apparatus and method of the invention may be particularly well suited to the erection of relatively lightweight lattice type towers of the type shown but are not so limited. It may be contemplated that a wide variety of tower types and configurations may benefit from the apparatus and method of the invention.

The erection apparatus may be indicated at 5102 and may include a pair of rigid elongated members 5104, 5104 in generally triangular configuration straddling a base portion of the tower with the apex 5108 of the triangle spaced substantially above the tower and with the elongated members arranged laterally with respect to the arc of tower erection. At least one rigid elongated lift member 5110 may be provided and may have one end attached to the elongated members 5104, 5104 at their apex 5108 and an opposite end attached to the tower at 5112 in remotely spaced relationship with the apex 5108 of the elongated members 5104, 5104. Further, a pair of fluid pressure operated cylinders 5114, 5114 may also be provided and may be arranged in a triangular configuration laterally straddling the tower 5100 each with an upper end secured to the elongated members 5104, 5104 at their apex 5108 and with their lower ends supported in laterally spaced relationship with the tower 5100. In an embodiment, the elongated members 5104, 5104 may be pivotally supported at their lower end portions and a representative mounting device shown at 5118 may be employed for each of said members.

Referring to FIG. 52, a schematic side view of the apparatus 5102 and the tower 5100 demonstrating the erection procedure is depicted. A pivot pin may be connected with and supports an elongated member 5104 and may be mounted in housing for rotation through an arc of approximately ninety degrees as required during tower erection. The housing may be secured to a foundation by bolts and the pivot pins for the two elongated members may be maintained in axial alignment.

In an alternative and preferred embodiment of the pivotal support for the elongated members 5104, 5104 are shown in FIG. 54A. FIGS. 54A and 54B depict an enlarged view in section showing a pivotal support for the tower 5100 and the connection of an elongated member to the tower 5100. In an embodiment, a pivot pin 5402 may be mounted in a boss 5424 on a member 5404. The member 5404 may in turn be secured to a foundation 5408 by bolts 5410, 5410. Further, the pivot pin 5402 may be connected with a generally L-shaped member 5410 that may be connected with and may support the lower end portion of a main corner member 5412 forming an integral part of the tower 5100. Also connected with the lower end portion of the member 5412 may be a lower end portion of an elongated member 5104 by means of bolts 5414, 5414. Thus, the elongated member 5104 may pivot with the member 5412 and the tower 5100 during erection of the latter. The pivot pin 5402 may rotate through approximately 90 degrees during erection of the tower 5100 and a stop 5420 on the member 5404 may serve to position the tower 5100 precisely in its vertical attitude on engagement of the member 5420 with a co-operating stop 5422 on the base of the tower member 5412. Thus, both the tower member 5412 and the elongated member 5104 may move together through an angle of approximately 90 degrees in an erection operation.

Further, a pair of fluid pressure cylinders and their extensions may also pivot through an angle of approximately 90 degrees during erection. In an embodiment, due to increase in length during the erection procedure a slight degree of freedom in the lateral direction may also be required. Accordingly, a two dimensional pivot capability may be provided at both ends of the cylinders and their extensions by means of conventional ball joint connections, not shown.

Referring to FIG. 53, a schematic view showing the tower 5100 in a position of substantial erection where cylinders commence a resistive action is depicted. The method of the present invention may be apparent in conjunction with FIGS. 52 and 53. The aforementioned elongated members 5104, 5104, lift member 5110, and fluid pressure cylinders may be positioned as shown in FIG. 52 on the pivotal supports of 54A, the elongated members and fluid pressure cylinders at approximately 11 o'clock in FIG. 52 and the tower 5100 in a substantially horizontal position. The fluid pressure cylinders may then be operated in a pushing mode to urge the pistons of the cylinders upwardly and to cause the elongated members and the lift member 5110 to swing arcuately upwardly and rightwardly to the position shown in FIG. 53. During this operation the elongated members and the cylinders swing through an arc in a clockwise direction. When the tower 5100 may have swung upwardly through an arc bringing its center of gravity 5302 into vertical alignment above the pivot point 5304 of the tower 5100 as shown in FIG. 53, the tendency of the tower 5100 may be to continue in its clockwise movement, accelerating as it moves. Accordingly, at approximately eighty degrees in the illustrative embodiment shown, the fluid pressure cylinders may be reversed and assume a resistive or pulling mode controlling the movement of the tower so that it may gradually come to rest in a vertical position with the stop members 5420 and 5422 of FIG. 54A in engagement.

Disclosed herein is the use of hydraulic cylinders, such as in the erection apparatus, to tip up the tower after it has been constructed horizontally on the ground, eliminating the need for a crane on site which would add considerable expense. The hydraulic cylinders may be attached to the discrete foundations members for the outriggers that are spaced apart from the main tower foundations. Referring to FIG. 55, a perspective view showing the erection apparatus disconnected from the tower 5100 and in a preliminary substantially horizontal attitude is depicted. Further, the erection apparatus, which may be preferably detachably connected to the tower 5100 and its pivot supports, may then be removed from the tower 5100 and employed in the erection of the next succeeding tower. At this point, it may be noted that the pivot supports and foundations for the fluid pressure cylinders may be positioned so as to be employed subsequently in the installation of diagonal outriggers supporting the tower.

Finally, the erection apparatus may be transported to the tower site, such as in a relatively small truck even in the most difficult terrain; ]the problems with access encountered with large cranes are overcome. On arrival at the site, the erection apparatus may be attached with its elongated members secured to independent pivot supports, the fluid pressure operated cylinders similarly mounted on their ball joint supports, and the apparatus arranged in a preliminary prone position as shown in FIG. 55. That is, the apparatus may extend rightwardly away from the tower and may be substantially horizontal but may be elevated slightly at its end remote from the tower. The fluid cylinders may then be operated in a retractive or pulling mode to cause the apparatus to swing upwardly and leftwardly in a counter-clockwise direction to its broken-line operating position. The lift member may then be attached and a simple and efficient method of installation of the erection apparatus completed.

The methods and systems described herein may be deployed in part or in whole through a machine that executes computer software, program codes, and/or instructions on a processor. The processor may be part of a server, cloud server, client, network infrastructure, mobile computing platform, stationary computing platform, or other computing platform. A processor may be any kind of computational or processing device capable of executing program instructions, codes, binary instructions and the like. The processor may be or include a signal processor, digital processor, embedded processor, microprocessor or any variant such as a co-processor (math co-processor, graphic co-processor, communication co-processor and the like) and the like that may directly or indirectly facilitate execution of program code or program instructions stored thereon. In addition, the processor may enable execution of multiple programs, threads, and codes. The threads may be executed simultaneously to enhance the performance of the processor and to facilitate simultaneous operations of the application. By way of implementation, methods, program codes, program instructions and the like described herein may be implemented in one or more thread. The thread may spawn other threads that may have assigned priorities associated with them; the processor may execute these threads based on priority or any other order based on instructions provided in the program code. The processor may include memory that stores methods, codes, instructions and programs as described herein and elsewhere. The processor may access a storage medium through an interface that may store methods, codes, and instructions as described herein and elsewhere. The storage medium associated with the processor for storing methods, programs, codes, program instructions or other type of instructions capable of being executed by the computing or processing device may include but may not be limited to one or more of a CD-ROM, DVD, memory, hard disk, flash drive, RAM, ROM, cache and the like.

A processor may include one or more cores that may enhance speed and performance of a multiprocessor. In embodiments, the process may be a dual core processor, quad core processors, other chip-level multiprocessor and the like that combine two or more independent cores (called a die).

The methods and systems described herein may be deployed in part or in whole through a machine that executes computer software on a server, client, firewall, gateway, hub, router, or other such computer and/or networking hardware. The software program may be associated with a server that may include a file server, print server, domain server, internet server, intranet server and other variants such as secondary server, host server, distributed server and the like. The server may include one or more of memories, processors, computer readable media, storage media, ports (physical and virtual), communication devices, and interfaces capable of accessing other servers, clients, machines, and devices through a wired or a wireless medium, and the like. The methods, programs or codes as described herein and elsewhere may be executed by the server. In addition, other devices required for execution of methods as described in this application may be considered as a part of the infrastructure associated with the server.

The server may provide an interface to other devices including, without limitation, clients, other servers, printers, database servers, print servers, file servers, communication servers, distributed servers, social networks, and the like. Additionally, this coupling and/or connection may facilitate remote execution of program across the network. The networking of some or all of these devices may facilitate parallel processing of a program or method at one or more location without deviating from the scope of the invention. In addition, any of the devices attached to the server through an interface may include at least one storage medium capable of storing methods, programs, code and/or instructions. A central repository may provide program instructions to be executed on different devices. In this implementation, the remote repository may act as a storage medium for program code, instructions, and programs.

The software program may be associated with a client that may include a file client, print client, domain client, internet client, intranet client and other variants such as secondary client, host client, distributed client and the like. The client may include one or more of memories, processors, computer readable media, storage media, ports (physical and virtual), communication devices, and interfaces capable of accessing other clients, servers, machines, and devices through a wired or a wireless medium, and the like. The methods, programs or codes as described herein and elsewhere may be executed by the client. In addition, other devices required for execution of methods as described in this application may be considered as a part of the infrastructure associated with the client.

The client may provide an interface to other devices including, without limitation, servers, cloud servers, other clients, printers, database servers, print servers, file servers, communication servers, distributed servers and the like. Additionally, this coupling and/or connection may facilitate remote execution of program across the network. The networking of some or all of these devices may facilitate parallel processing of a program or method at one or more location without deviating from the scope of the invention. In addition, any of the devices attached to the client through an interface may include at least one storage medium capable of storing methods, programs, applications, code and/or instructions. A central repository may provide program instructions to be executed on different devices. In this implementation, the remote repository may act as a storage medium for program code, instructions, and programs.

The methods and systems described herein may be deployed in part or in whole through network infrastructures. The network infrastructure may include elements such as computing devices, servers, cloud servers, routers, hubs, firewalls, clients, personal computers, communication devices, routing devices and other active and passive devices, modules and/or components as known in the art. The computing and/or non-computing device(s) associated with the network infrastructure may include, apart from other components, a storage medium such as flash memory, buffer, stack, RAM, ROM and the like. The processes, methods, program codes, instructions described herein and elsewhere may be executed by one or more of the network infrastructural elements.

The methods, program codes, and instructions described herein and elsewhere may be implemented on a cellular network having multiple cells. The cellular network may either be frequency division multiple access (FDMA) network or code division multiple access (CDMA) network. The cellular network may include mobile devices, cell sites, base stations, repeaters, antennas, towers, and the like. The cell network may be a GSM, GPRS, 3G, EVDO, mesh, or other networks types.

The methods, programs codes, and instructions described herein and elsewhere may be implemented on or through mobile devices. The mobile devices may include navigation devices, cell phones, mobile phones, mobile personal digital assistants, laptops, palmtops, netbooks, pagers, electronic books readers, music players and the like. These devices may include, apart from other components, a storage medium such as a flash memory, buffer, RAM, ROM and one or more computing devices. The computing devices associated with mobile devices may be enabled to execute program codes, methods, and instructions stored thereon. Alternatively, the mobile devices may be configured to execute instructions in collaboration with other devices. The mobile devices may communicate with base stations interfaced with servers and configured to execute program codes. The mobile devices may communicate on a peer to peer network, mesh network, or other communications network. The program code may be stored on the storage medium associated with the server and executed by a computing device embedded within the server. The base station may include a computing device and a storage medium. The storage device may store program codes and instructions executed by the computing devices associated with the base station.

The computer software, program codes, and/or instructions may be stored and/or accessed on machine readable media that may include: computer components, devices, and recording media that retain digital data used for computing for some interval of time; semiconductor storage known as random access memory (RAM); mass storage typically for more permanent storage, such as optical discs, forms of magnetic storage like hard disks, tapes, drums, cards and other types; processor registers, cache memory, volatile memory, non-volatile memory; optical storage such as CD, DVD; removable media such as flash memory (e.g. USB sticks or keys), floppy disks, magnetic tape, paper tape, punch cards, standalone RAM disks, Zip drives, removable mass storage, off-line, and the like; other computer memory such as dynamic memory, static memory, read/write storage, mutable storage, read only, random access, sequential access, location addressable, file addressable, content addressable, network attached storage, storage area network, bar codes, magnetic ink, and the like.

The methods and systems described herein may transform physical and/or or intangible items from one state to another. The methods and systems described herein may also transform data representing physical and/or intangible items from one state to another.

The elements described and depicted herein, including in flow charts and block diagrams throughout the figures, imply logical boundaries between the elements. However, according to software or hardware engineering practices, the depicted elements and the functions thereof may be implemented on machines through computer executable media having a processor capable of executing program instructions stored thereon as a monolithic software structure, as standalone software modules, or as modules that employ external routines, code, services, and so forth, or any combination of these, and all such implementations may be within the scope of the present disclosure. Examples of such machines may include, but may not be limited to, personal digital assistants, laptops, personal computers, mobile phones, other handheld computing devices, medical equipment, wired or wireless communication devices, transducers, chips, calculators, satellites, tablet PCs, electronic books, gadgets, electronic devices, devices having artificial intelligence, computing devices, networking equipments, servers, routers and the like. Furthermore, the elements depicted in the flow chart and block diagrams or any other logical component may be implemented on a machine capable of executing program instructions. Thus, while the foregoing drawings and descriptions set forth functional aspects of the disclosed systems, no particular arrangement of software for implementing these functional aspects should be inferred from these descriptions unless explicitly stated or otherwise clear from the context. Similarly, it will be appreciated that the various steps identified and described above may be varied, and that the order of steps may be adapted to particular applications of the techniques disclosed herein. All such variations and modifications are intended to fall within the scope of this disclosure. As such, the depiction and/or description of an order for various steps should not be understood to require a particular order of execution for those steps, unless required by a particular application, or explicitly stated or otherwise clear from the context.

The methods and/or processes described above, and steps thereof, may be realized in hardware, software or any combination of hardware and software suitable for a particular application. The hardware may include a general purpose computer and/or dedicated computing device or specific computing device or particular aspect or component of a specific computing device. The processes may be realized in one or more microprocessors, microcontrollers, embedded microcontrollers, programmable digital signal processors or other programmable device, along with internal and/or external memory. The processes may also, or instead, be embodied in an application specific integrated circuit, a programmable gate array, programmable array logic, or any other device or combination of devices that may be configured to process electronic signals. It will further be appreciated that one or more of the processes may be realized as a computer executable code capable of being executed on a machine readable medium.

The computer executable code may be created using a structured programming language such as C, an object oriented programming language such as C++, or any other high-level or low-level programming language (including assembly languages, hardware description languages, and database programming languages and technologies) that may be stored, compiled or interpreted to run on one of the above devices, as well as heterogeneous combinations of processors, processor architectures, or combinations of different hardware and software, or any other machine capable of executing program instructions.

Thus, in one aspect, each method described above and combinations thereof may be embodied in computer executable code that, when executing on one or more computing devices, performs the steps thereof. In another aspect, the methods may be embodied in systems that perform the steps thereof, and may be distributed across devices in a number of ways, or all of the functionality may be integrated into a dedicated, standalone device or other hardware. In another aspect, the means for performing the steps associated with the processes described above may include any of the hardware and/or software described above. All such permutations and combinations are intended to fall within the scope of the present disclosure.

While the invention has been disclosed in connection with the preferred embodiments shown and described in detail, various modifications and improvements thereon will become readily apparent to those skilled in the art. Accordingly, the spirit and scope of the present invention is not to be limited by the foregoing examples, but is to be understood in the broadest sense allowable by law.

All documents referenced herein are hereby incorporated by reference.

	Number	Date	Country
Parent	12077556	Mar 2008	US
Child	13215140		US
Parent	12315943	Dec 2008	US
Child	12077556		US
Parent	12286054	Sep 2008	US
Child	12315943		US
Parent	12929000	Dec 2010	US
Child	12286054		US
Parent	12286055	Sep 2008	US
Child	12929000		US
Parent	12454526	May 2009	US
Child	12286055		US
Parent	12454527	May 2009	US
Child	12454526		US
Parent	12454823	May 2009	US
Child	12454527		US
Parent	12586998	Sep 2009	US
Child	12454823		US
Parent	12592909	Dec 2009	US
Child	12586998		US
Parent	12460985	Jul 2009	US
Child	12592909		US
Parent	12217916	Jul 2008	US
Child	12460985		US
Parent	12006024	Dec 2007	US
Child	12217916		US
Parent	12077556	Mar 2008	US
Child	12006024		US

STRUCTURE AND ACCELERATOR PLATFORM PLACEMENT FOR A WIND TURBINE TOWER

Information

Publication Number

Date Filed

Date Published

Inventors

Original Assignees

CPC

US Classifications

International Classifications

Abstract

Description

Claims

CROSS-REFERENCE TO RELATED APPLICATIONS

Continuation in Parts (14)