Abstract:
A wind turbine is provided which comprises a plurality of blades and a single venturi disposed at a central area of the plurality of blades. The single venturi redirects the wind from a concave side of an active blade to the concave sides of the other blades. Also, the single venturi reduces turbulent flow of air out of the venturi and redirects the flow of air against the adjacent blades.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    Not Applicable 
       STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT 
       [0002]    Not Applicable 
       BACKGROUND 
       [0003]    The present invention is related to a fluid (wind) turbine. 
         [0004]    Environmentally friendly electrical generating systems have become a major issue in today&#39;s society due to the harmful effects of emissions from burned fuel causing a global warming effect. Accordingly, devices have been invented to harness energy in an environmentally friendly manner. Such devices include a wind operated turbine that converts wind energy into electricity and/or mechanical energy for various types of work. 
         [0005]    Prior art wind turbines may have two concave shaped wings attached to a central shaft, as shown in  FIG. 1 . The wind blows against the concave side of the first wing and against a convex side of a second wing. The force applied against the concave side is greater than the force applied against the convex side. Accordingly, the wind pushes against the wings and rotates the shaft. The rotating shaft may be coupled to a generator to generate electricity. Unfortunately, prior art wind turbines are inefficient at converting wind energy into electricity. An example of prior art wings of a turbine is described in U.S. Pat. No. 4,005,947 (hereinafter the &#39;947 patent). 
         [0006]    To improve upon the basic design of the winged wind turbine, the prior art wing turbines also include an offset wings configuration, as shown in  FIG. 2 . In this example, the wind flows against the concave side of one of the wings and is redirected to the concave side of the following wing. The redirected wind pushes against the concave side of the following wing to help increase the pressure against the concave side of the following wing. This reduces the pressure difference between the concave and convex sides of the following wings thereby assisting in the rotation of the shaft. 
         [0007]    The &#39;947 patent also discusses an alternative embodiment that more efficiently redirects the wind against the following blade. In particular, as understood, the &#39;947 patent introduces a central vein which is fixed in relation to the wings. The central vein and the wings provide flow paths to redirect the wind against the other blades. 
         [0008]    The wind turbine discussed herein is an alternative embodiment which aids in efficiently converting wind energy into electrical energy or mechanical energy. 
       BRIEF SUMMARY 
       [0009]    The wind turbine discussed herein addresses the needs discussed above, discussed below and those that are known in the art. 
         [0010]    The wind turbine may comprise a rotor assembly comprising a plurality of blades symmetrically disposed about a rotating axis of the rotor assembly. The wind may blow against the plurality of blades and be operative to rotate the plurality of blades. A venturi may be disposed at a central area of the blades such that wind exiting the venture is redirected in a less turbulent manner to adjacent blades. 
         [0011]    In an aspect of the wind turbine, the leading edges of the blades may be folded. 
         [0012]    In another aspect of the wind turbine, the leading portions and trailing portions of the blades may be tangentially aligned to a circle defined by the leading edges and the trailing edges of the blades. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which like numbers refer to like parts throughout, and in which: 
           [0014]      FIG. 1  is an illustration of a prior art winged turbine; 
           [0015]      FIG. 2  is an illustration of a prior art winged turbine with offset wings to redirect wind to a concave side of a following wing; 
           [0016]      FIG. 3  is an illustration of a prior art winged turbine with offset wings and a central vein to redirect wind to adjacent blades; 
           [0017]      FIG. 4  is a perspective view of a wind turbine; 
           [0018]      FIG. 5  is a top cross sectional view of a rotor assembly of the wind turbine shown in  FIG. 4 ; 
           [0019]      FIG. 6  is a top cross sectional view of a blade with bent and a crimped leading portion. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    Referring now to  FIG. 4 , a turbine  10  is illustrated. The turbine  10  may be operative to rotate a shaft  14  for generating electricity or other types of work. The turbine  10  will be discussed in relation to the flow of wind across the turbine  10  but may be applicable to other types of fluid such as liquid, water, etc. Accordingly, the various aspects of the turbine  10  disclosed herein are also applicable to other types of fluid media. 
         [0021]    The turbine  10  may comprise a frame  12 , a rotatable shaft  14  and a rotor assembly  16 . A plurality of rotor assemblies may be stacked in two sets of three rotor assemblies as shown in  FIG. 4 . The rotatable shaft  14  may be mounted to the frame  12  with bearings to allow relatively frictionless rotation of the shaft  14  to the frame  12 . The rotor assembly  16  may be mounted to the shaft  14  at various angular orientations. The turbine  10  may be located in any area but is preferably located in windy areas in order to provide sufficient wind energy to the turbine  10 . The turbine  10  may convert the wind energy into electricity or other types of work. Generally, wind may blow against the rotor assembly  16  thereby rotating the rotor assembly  16 . Since the shaft  14  is attached to the rotor assembly and aligned to a rotating axis  18  of the rotor assembly  16 , the rotation of the rotor assembly  16  is operative to also rotate the shaft  14 . The shaft  14  may be coupled to a generator  17  to generate electricity. Alternatively, the shaft may be directly attached to a device to directly provide energy to the device for operating the device. 
         [0022]    The rotor assembly  16  may have a plurality of blades  20  symmetrically positioned about a rotating axis  18 . Upper and lower plates  19 ,  21  may be attached to the upper and lower edges of the blades  20 , as shown in  FIG. 4 . As shown in  FIG. 5 , the rotor assembly  16  may have three blades  20   a, b, c  which are positioned about the rotating axis  18  in a symmetrical manner. During use, the wind blows against the blades  20  of the rotor assembly  16 . When the wind contacts the concave side  22 , the wind pushes against the blade  20  with a force X. When the wind contacts the convex side  24  of the blades  20 , the wind pushes against the blade with a force Y. The force X is generally greater than the force Y. Accordingly, the rotor assembly  16  shown in  FIGS. 4 and 5  rotates in a clockwise direction. Although the rotor assembly  16  will be discussed in relation to a clockwise rotating rotor assembly, it is contemplated that the various aspects of the turbine  10  may be variously embodied and employed in a counter clockwise rotating rotor assembly  16 . To this end, the blades  20  may be fabricated in a mirror configuration. 
         [0023]    During operation, the wind simultaneously blows against the active blade and a following blade. In  FIG. 5 , the arrows  23  represent wind. The active blade is the blade  20   a  upon which the wind  23  directly blows against the concave side  22 . The following blade is blade  20   c  immediately adjacent to the active blade on the counter clockwise side of the active blade. When the wind  23  contacts the concave side  22  of the active blade, the wind  23  is redirected toward the center of the rotor assembly  16 . The wind  23  enters a venturi  26  which redirects the wind  23  against the concave sides  22  of the following blade  20   c  and a preceding blade  20   a . The redirected wind increases the pressure applied against the concave sides  22  of the following blade and the preceding blade. As the rotor assembly  16  rotates in the clockwise direction, the wind produces a positive pressure against the concave side  22  of the active blade. The throughput of wind through the venture is less than the speed of the wind thereby pressure builds on the concave side  22  of the active blade. Conversely, the concave sides  22  of the following blade and the preceding blade experience a negative pressure. To reduce the negative pressure or to provide a positive pressure against the concave sides  22  of the following blade and the preceding blade, the wind blown against the concave side  22  of the active blade is redirected by the venturi  26  to the concave sides  22  of the following blade and the preceding blade. 
         [0024]    As the wind enters the venturi  26 , the wind accelerates through the narrow section of the venturi  26 . The venturi  26  shown in  FIG. 5  is a three way venturi but a two way venturi for a two bladed rotor assembly or a multi-way venturi for a multi-bladed rotor assembly is contemplated. The wind is then redirected toward the concave sides  22  of the following blade and the preceding blade but is slowed down by the widening or expansion of the venturi&#39;s exit portion. The wind is slowed down to reduce the turbulent flow of air through the venturi  26  and provide more laminar flow of air against the concave sides  22  of the following and preceding blades. The flow of air against the concave sides  22  of the following and preceding blades provide rotational thrust on the blades  24 . 
         [0025]    The blades  20  may each define a leading portion  28 , leading edge  30 , trailing portion  32  and a trailing edge  34 . The leading edges  30  may be equally distantly spaced a part from each other and also equally distantly spaced from the rotating axis  18  of the rotor assembly  16 . The leading edges  30   a, b  and  c  of the blades  20   a, b  and  c  may define a circle which is aligned to the outer perimeter  36  of the lower plate  21 , as shown in  FIG. 5 . The leading portions  28   a, b  and  c  of the blades  20   a, b  and  c  may extend tangentially from the outer perimeter  36  and curve inward toward the central area of the rotor assembly  16 . 
         [0026]    Similarly, the trailing edges  34   a, b  and  c  of the blades  20   a, b  and  c  may be equally distantly spaced apart from each other as well as from the rotating axis  18 . The trailing edges  34   a, b  and  c  of the blades  20   a, b  and  c  may define a circle  38 . As the blades  20   a, b  and  c  curve inward toward the central area of the rotor assembly  16 , the trailing portions  32   a, b  and  c  of the blades  20   a, b  and  c  may be tangentially aligned to the circle  38 . 
         [0027]    In an aspect of the turbine  10 , the leading portions  28   a, b, c  of the blades  20   a, b, c  may be bent and crimped, as shown in  FIG. 6 . The bent and crimped leading portion provides reinforcement or additional strength along a height of the blade so as to prevent the leading portion from bending in high winds or at high rotational speeds. In high winds, the upper and lower points of the leading portions are fixedly attached to the upper and lower plates  19 ,  21 , as shown in  FIG. 4 . However, the high winds may place an excessive amount of pressure against the middle of the leading portions  28 . The excessive pressure may tend to bend the leading portions. Fortunately, the leading portion  28  may be reinforced by bending and crimping the leading portion  28  of the blade  20  (see  FIG. 6 ) to prevent deformation of the leading portion  28 . 
         [0028]    In an aspect of the turbine  10 , the venturi  26  may be sized to provide optimum performance and efficiency of the blades  20 . More particularly, the venturi  26  may be defined by the circle  38  (see  FIG. 5 ). The trailing edges  34   a, b, c  of the blades  20   a, b , and  c  may be aligned to the circle  38  to maintain symmetry and balance of the rotating blades  20   a, b , and  c  to the rotating axis  18 . Based on the specific configuration of the blades  20   a, b , and  c  and other factors, the size of the venturi  26  defined by the trailing edges  34   a, b, c  and the trailing portions  32   a, b, c , the size of the circle  38  to which the trailing edges  34   a, b, c  are aligned to may be enlarged or reduced to provide the optimum performance and efficiency of the rotating blades  20   a, b , and  c.    
         [0029]    The above description is given by way of example, and not limitation. Given the above disclosure, one skilled in the art could devise variations that are within the scope and spirit of the invention disclosed herein, including various ways of incorporating the various aspects of the turbine  10  to turbines in relation to other fluid media. Further, the various features of the embodiments disclosed herein can be used alone, or in varying combinations with each other and are not intended to be limited to the specific combination described herein. Thus, the scope of the claims is not to be limited by the illustrated embodiments.