Patent Publication Number: US-7905705-B2

Title: Adaptable flow-driven energy capture system

Description:
RELATED APPLICATIONS 
     This application is a continuation application of application Ser. No. 11/205,752, filed Aug. 16, 2005 now U.S. Pat. No. 7,632,069. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The subject matter of the application generally relating to converting and storing the kinetic energy of a flowing fluid. More particularly, the subject matter of the application relates to the conversion and storage of wind power and hydropower. 
     2. Description of Related Art 
     Windmills and wind turbines are generally well known in the art. Windmills traditionally include a plurality of blades or vanes connected to a rotatable shaft. Wind (or other fluids) act upon the blades to create an aerodynamic or hydrodynamic reaction upon the blades causing the shaft and blades to rotate about the axis of the shaft. Windmills have traditionally been employed across the world to: pump water, grind grain and crush stone. Additionally, windmills have been employed in systems that convert kinetic energy, namely wind, into electrical energy. The rotation of the blades of a windmill drives a generator, which in turn produces an electric current. For applications that require linear actuation, additional mechanical systems are required to translate the rotation of the blades into such linear motion, further complexifying a windmill&#39;s operation. 
     Wind turbines are designed to work between certain wind speeds. The lower speed, called the ‘cut in speed’ is generally 4-5 ms −1 , as there is too little energy below this speed to overcome system losses. The ‘cut out speed’ is determined by the ability of the particular machine to withstand high wind. The ‘rated speed’ is the wind speed at which the particular machine achieves its maximum rated output. Above this speed, it may have mechanisms that maintain the output at a constant value with increasing wind speed. 
     Windmills and wind turbines require frequent repair and maintenance. Blades can be damaged by high winds and the complex mechanisms that have been devised to accommodate for such must be frequently inspected and maintained. Additionally, while windmills and wind turbines present emission-free options to oil- and gas-fueled power plants, they have been implicated in the annual deaths of tens of thousands of birds, some of which are endangered. Besides the loss of life, repair and maintenance are necessitated as a result of a number of such avian fatalities. 
     Hydropower plants operate similarly to harness the kinetic energy of flowing water to generate electricity. Hydropower plants generally include a dam, one or more turbines and a corresponding number of generators. Each turbine is positioned at the dam such that water flowing through the dam strikes and turns the turbine&#39;s blades. Each turbine is attached to a generator via a shaft such that rotation of the turbine turns the generator producing an electrical current. However, while wind turbines are designed to rotate orthogonal to airflow, hydropower turbines are generally designed to rotate parallel with water flow. Therefore, improvements to wind turbines are not easily translatable to hydropower turbines. 
     Therefore, what is needed in the art is a system for capturing and storing the kinetic energy of a flowing fluid. What is further needed is such a system that is simpler in construction and provides greater efficiencies than current wind turbines and/or hydropower turbines. Additionally, what is needed is a system that requires less maintenance and repair. 
     SUMMARY OF THE INVENTION 
     It is to the solution of the hereinabove mentioned problems to which the present invention is directed. In accordance with the present invention there is provided an adaptable flow-driven energy conversion system comprising: 
     A support mast having a base and a top, the support mast affixed to a surface at said base thereof; 
     A balance beam having a first end and a second end and extending therebetween, said balance beam comprising a force arm side extending from said second end thereof in the direction of said first end and a load arm side extending from said first end thereof in the direction of said second end, said force arm side and said load arm side coterminating at a balance beam fulcrum, said balance beam pivotally attached to the top of the support mast at the balance beam fulcrum; 
     A compensatory weight attached to the force arm side of the balance beam, said compensatory weight selected to equalize the weight disposed about the balance beam fulcrum; 
     A fluidfoil mast extending between at least one fluidfoil, defining two ends, said fluidfoil mast pivotally connected to the load arm side of said balance beam; 
     At least one fluidfoil pivotally attached to the fluidfoil mast, said at least one fluidfoil having a leading edge and a trailing edge cooperatively defining an edge axis extending therebetween, said fluidfoil further having an orthogonally disposed longitudinal axis; 
     An angle of attack positioner attached between the at least one fluidfoil and the fluidfoil mast, said positioner moderating fluidfoil angle of attack with respect to fluid flow; 
     A vane disposed posterior the at least one fluidfoil, said vane registering fluid flow forces that are not parallel with the fluidfoil edge axis; 
     At least one control rod having a support masthead end and a fluidfoil mast end, said control rod pivotally attached thereto and extending parallel the balance beam affixed to the support mast. 
     It is an objective to provide a fluidfoil and associated electromechanical assembly capable of extracting energy from low to high velocity prevailing winds for the conversion of such. 
     It is further an objective to provide for the selectable control of positive and negative lift on a fluidfoil by changing fluidfoil attitude. 
     It is another objective to provide an energy recapture device for conserving and reusing the energy forces required for controlling fluidfoil transitions from positive to negative lift related orientations. 
     The adaptable fluid flow-driven system is uniquely configured to oscillate in the presence of and orthogonal to the direction of fluid flow. Each of the at least one fluidfoil is dynamically positioned to promote a constant and optimum angle of attack. 
     A balance beam is rotatably affixed to a support mast at a fulcrum point. The balance beam comprises a force arm and a load arm with each extending from opposed ends of the balance beam and coterminating at the fulcrum. The force arm and the load arm are different lengths thereby providing the mechanical advantage that enables the oscillatory motion even in the presence of low energy fluid flow. Energy of such fluid flow is a function of the fluid density and velocity. 
     The support mast is affixed to a surface and includes a rotational portion disposed at a point along the length thereof such that the mast may rotate at a side of the rotational portion opposed the ground. 
     A counterweight is attached to the force arm such that the weight at either side of the balance beam fulcrum is substantially equivalent. Given the unequal lengths of the force arm and the load arm, there is a mechanical advantage at the force arm [side of the balance beam equal to the product of the length of the load arm multiplied by the length of the force arm. 
     A fluidfoil is aligned with a fluid flow by a vane attached at the force arm side of the fulcrum. Lift is created across the fluidfoil in proportion to fluid flow velocity and the characteristics of the fluidfoil well known to those skilled in the art of fluidfoils, such as airfoils. Control rods each extend equidistantly and parallel to the balance beam and are pivotally affixed to the support mast. 
     A fluidfoil mast is attached to the balance beam and control rods in a like manner and extends in parallel to the support mast. This arrangement forms a dynamic rhomboid assembly that allows the fluidfoil to maintain an optimum angle of attack into fluid flow by adjusting that angle. 
     An angle of attack positioning mechanism adjusts the fluidfoil&#39;s angle of attack to a constant positive or negative lift position thus enabling an up and down motion that produces lift in both directions and creating an energy converting capability from low velocity as well as high velocity fluid flows including wind and water flow. 
     Kinetic energy from the fluidfoil is transferred by the lever action of the rhomboid assembly to a connector for energy transfer to one of a variety of energy storage systems for converting the energy of the linear oscillating motion to other desired forms of energy. Such systems include generators or compressors or the like. 
     As the fluid foil oscillates through positive and negative lift modes, the energy expended to make the transition is partially recaptured by an energy recapture device. This is a dual function device that dampens and stops the upward or downward motion of the fluidfoil as the angle of attack positioner changes the fluidfoil from a positive to a negative lift or vice versa. 
     The transition point at which the foil changes from positive to negative lift and vice versa requires energy to be extracted from the positive upward momentum and stored as the action is stopped and turned around. An energy recapture device in conjunction with cam actions, solenoids, air compression pistons or calibrated springs is employed for this purpose. When this action is completed and the foil reverses its lift generating capability, the stored energy is transferred back to the foil by the energy releasing function of the energy recapture device to aid in quickly regenerating a negative lift component in the downward cycle. The same occurs in the negative to positive lift transition. 
     For a more complete understanding of the subject matter of the application, reference is made to the following detailed description and accompanying drawings. In the drawings, like reference characters refer to like parts, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of a preferred embodiment of an adaptable flow-driven energy capture system; 
         FIG. 2  is an elevated lateral perspective view of a balance beam and fluidfoil mast portions of an adaptable fluid flow-driven energy conversion system in accordance with the preferred embodiment; and 
         FIG. 3  is a side perspective view of the preferred embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings more particularly by reference numbers,  FIGS. 1 and 2  show an adaptable flow-driven energy capture system  100 . The system  100  is uniquely configurable to oscillate in the presence of and orthogonal to the direction of fluid flow (shown as ‘X’). Fluid flow may include airflow, running water, or some other fluid the properties of which fall within about the properties of water and air. 
     The system  100  generally includes a support mast  102 , a balance beam  104 , a counterweight  106 , an angle-of-attack positioner  108  and an at least one fluidfoil  110 . The support mast  102  has a base  112  and a top  114 , the support mast  102  is attached to a ground  116  at said base  112  thereof. The support mast  102  may be formed from corrosion resistant strong lightweight materials. Additionally, the material should withstand the forces associated with the reciprocating movement of the balance beam  104  resulting from movement of the at least one fluidfoil  110 . Aluminum, titanium, composite or some other material well known to one skilled in the art may be used. 
     The balance beam  104  has a first end  118  and a second end  120  and extends therebetween. The balance beam  104  is preferably formed from a strong, lightweight material that resists corrosion. Such materials are well known in the art and include aluminum, titanium, or some other material well known for such properties. The balance beam  104  comprises a force arm side  122  extending from said first end  118  thereof in the direction of said second end  120  and a load arm side  124  extending from said second end  120  thereof in the direction of said first end  118 , said force arm side  122  and load arm side  124  each coterminate at a balance beam fulcrum  126 . The balance beam  104  is pivotally and rotatably attached at the top  114  of the support mast  102  at the balance beam fulcrum  126 . 
     The force arm side  122  and the load arm side  124  are different lengths. More particularly, the load arm side  124  of the balance beam  104  is longer than the force arm side  122  providing a mechanical advantage at the force arm side  122  of the balance beam  104 . As discussed further hereinbelow, by configuring the relative lengths of the force arm side  122  and the load arm side  124 , one is able to configure the system  100  depending upon the conditions under which the system is operating. 
     As shown in  FIG. 3 , the support mast  102  houses a bearing  302  to which is affixed a support masthead  304  that extends coaxially and rotates about a longitudinal axis of the support mast  102 . Force sensing means  306  sense rotational forces at the bearing  302 . Such force sensors are known to those skilled in the art and as such shall not be further discussed herein. The support masthead  304  is preferably formed from materials known to those skilled in the art to function similarly to those comprising the balance beam  104  and the support mast  102 . 
     Referring back to  FIGS. 1 and 2 , the counterweight  106  is attached to the force arm side  122  of the balance beam  104  and is selected to equalize the weight at either side of the fulcrum  126 . The means for attaching the counterweight  106  preferably provide for removably attaching the counterweight  106  such as clamping or bolting, or some other means for removable attachment well known to those skilled in the art. The unequal lengths of the force arm side  122  and the load arm side  124  create a mechanical advantage at the force arm side  122  of the balance beam  104 . 
     A fluidfoil mast  128  has a first end  130  and a second end  132  and extends therebetween. The fluidfoil mast  128  is pivotally connected at the load arm side  124  of the balance beam  104 . Each at least one fluidfoil  110  is pivotally attached to the fluidfoil mast  128  at a fluidfoil pivot point  134 . The fluidfoil mast  128  additionally comprises a center section  136  having two opposed ends  138 ,  139 . End sections  140 ,  141  are rotatably attached one at each end  138 ,  139  through a motor or some other well-known means for rotating  142  one element relative another. In this fashion, each of the at least one fluid foils  110  can be rotated about the longitudinal axis of the foil support mast  128  as described hereinbelow in greater detail. 
     Referring back to  FIGS. 1 and 2 , each fluidfoil  110  comprises a leading edge  202  and a trailing edge  204  that define an edge axis (Y) extending therebetween. As most easily viewed in  FIG. 2 , each at least one fluidfoil  110  further defines a longitudinal axis (Z). While the system  100  will function with at least one fluidfoil  110  as disclosed, it is to be appreciated that the at least one fluidfoil  110  in the preferred embodiment comprises two substantially identical fluidfoils. In other embodiments, the system  100  can have more than two substantially identical fluidfoils. 
     Lift is created across the at least one fluidfoil  110  in proportion to fluid flow velocity and characteristics of the fluidfoil  110  well known to those skilled in the art of fluidfoils, including airfoils. Control rods  144 ,  145  each extend preferably equidistantly and parallel to the balance beam  104  and are pivotally affixed to the support masthead  304  and the fluidfoil mast  128  respectively via well-known pivotal mounting means. This arrangement forms a dynamic rhomboid assembly that allows the fluidfoil  110  to maintain an optimum angle of attack into fluid flow by restricting the travel of the fluidfoil mast  128  to remain perpendicular to the ground  116 . 
     The angle of attack positioner  108  is attached between the at least one fluidfoil  110  and the fluidfoil mast  128 . By pivoting the at least one fluidfoil  110  about pivot point  134 , the angle of attack positioner  108  moderates the at least one fluidfoil&#39;s  110  angle of attack with respect to fluid flow X therepast. As such, each of the at least one fluidfoil  110  is alternatingly positioned to maintain the angle of attack at a generally constant positive or negative lift position depending upon the direction of travel of the balance beam  104 . Sensing means  308 , such as an optical encoder, potentiometer or other well-known rotational sensors is preferably disposed about the fulcrum. 
     When the balance beam  104  reaches the limit of travel as indicated by the position indicated by the sensing means  308 , the angle of attack positioner  108  is activated to reverse the angle of attack. As such, given the configuration of the preferred embodiment, the angle of attack positioner  108  is configured to receive such control signals. Varying the angle of attack enables the reciprocating up and down motion that produces lift in both directions and facilitates energy conversion from low velocity as well as high velocity fluid flows. Note that the terms ‘up’ and ‘down’ are with respect to the defined ground  116 . 
     While fluid flow velocity is within a predetermined range, the positioner  108  maintains the fluidfoil  110  at an optimum angle of attack to provide maximum lift. When fluid flow exceeds such a range, positioner  108  alters the angle of attack, effectively reducing lift to guard against damaging the system  100 . A fluid flow meter  154 , such as but not limited to the WindMate wind meter produced by SpeedTech, Inc., located in Great Falls, Va. 22066, can be used to measure wind speed. Such information is used to adjust the angle of attack at times when wind speeds exceed a selected threshold. Wind meters are well known to those skilled in the art and as such shall not be discussed further herein. 
     As the at least one fluidfoil  110  oscillates through positive and negative lift modes, the energy expended to make the transition between such is partially recaptured by an energy recapture device  146 . The energy recapture device  146  dampens and stops the upward or downward motion of the at least one fluidfoil  110  as the angle of attack positioner  108  changes the fluidfoil from a positive to a negative lift or vice versa. 
     A transition point at which the fluidfoil  110  changes from positive to negative lift and vice versa requires energy to be extracted from the travel momentum and stored as the action is stopped and turned around. An energy recapture device  146  in conjunction with cam actions, solenoids, air compression pistons or calibrated springs is employed for this purpose. Such devices and their function with regard to reciprocating motion are well known in the art. As the balance beam  104  reaches its maximum travel, the energy recapture device  146  drives the movement of the balance beam  104  in the opposite direction from that it was traveling to aid in quickly regenerating a negative lift component in the downward cycle. The same occurs in the negative to positive lift transition. 
     A vane  148  is attached posterior to the at least one fluid foil  110 . Preferably the vane  148  is positioned at the second end  120  of the balance beam  104 . The vane  148  is configured so that fluid flow incident thereto serves to apply rotational force at the force sensing means  306  at the bearing  302 . The rotational force, or torque, at the bearing  302  is communicated to the means for rotating  142  to rotate the at least one fluidfoil  110 , about the fluidfoil support mast  128 , in response to the sensed torque. In another embodiment, rotation in response to the sensed torque takes place at the bearing  302  and not about the fluidfoil mast  128 . In yet another embodiment, rotation in response to the sensed torque takes place at both the bearing  302  and about the fluidfoil mast  128 . 
     The vane  148  is attached to the balance beam  104  via well-known mounting means including brackets, or bolts and is preferably removably mounted to ease in repair or replacement if such is required. Alternatively, the vane  148  may be permanently affixed by welding or some other well-known means for permanent attachment. Additionally, the vane  148  is preferably formed from a lightweight corrosion-resistant material consistent with the other elements of the preferred embodiment. 
     Kinetic energy from the fluidfoil is transferred by the lever action of the rhomboid assembly to a connector  150  for energy transfer to one of a variety of energy storage systems for converting the energy of the linear oscillating motion to other desired forms of energy. Such systems include, for example electrical generators. Alternatively, the connector  150  may drive a compressor  152  for compressing air. 
     While certain exemplary embodiments of the present invention have been described and shown on the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive on the broad invention, and that this invention not be limited to the specific constructions and arrangements shown and described, since various other modifications may occur to those ordinarily skilled in the art. As such, what is claimed is: