Patent Publication Number: US-2009238676-A1

Title: Accelerator for use in a wind power electrical generating system

Description:
BACKGROUND OF THE INVENTION 
     Twin wind turbines mounted on a common rotatable support for rotation about horizontal axes are shown in the following U.S. Patents, disclosures incorporated herein by reference:
         U.S. Pat. No. 4,021,140       

     Reference is also had to: U.S. patent application Ser. No. 11/820741 filed Jun. 19, 2007 entitled IMPROVED CONTROL SYSTEM FOR TWIN TURBINE WIND POWER GENERATING SYSTEM invented by Russel H. Marvin, hereby incorporated herein by reference, 
     U.S. Patent Application entitled IMPROVED GENERATOR OUTPUT CIRCUITRY FOR TWIN TURBINE WIND POWER GENERATING SYSTEM, filed Sep. 21, 2007, invented by Russel H. Marvin, hereby incorporated herein by reference, and 
     U.S. Patent Application entitled SYSTEM FOR OPERATING A GENERATOR AS A MOTOR IN A TURBINE WIND POWER GENERATING SYSTEM, filed Sep. 21, 2007, invented by Russel H. Marvin, hereby incorporated herein by reference. 
     U.S. Patent Application entitled IMPROVED INLET PASSAGEWAY AND SEALING IN A TURBINE WIND POWER GENERATING SYSTEM, filed Dec. 28, 2007, invented by Russel H. Marvin, hereby incorporated herein by reference. 
     Improved control systems for operating the apparatus of the aforesaid patents and improvements in airflow control and sealing of the turbines are disclosed in the aforementioned applications. The present application relates to an accelerator construction of lightweight high strength characteristics and durability under the severe conditions of temperature and humidity change in outdoor operation. 
     It is the general object of the present invention to provide a separator construction which meets the aforesaid criteria and which may be constructed at economic advantage. 
    
    
     SUMMARY OF THE INVENTION 
     In fulfillment of the foregoing object and in accordance with the present invention an accelerator for use in a wind power electrical generating system has at least one variable speed wind turbine axis mounts the turbine for rotation about a horizontal axis and defines an outwardly open recess forming an airflow passageway. The airflow passageway captures and directs a stream of wind through an arcuate acceleration path to the wind turbine. The accelerator comprises a cage-like structure of thin lightweight supporting members connected together in a configuration which defines the three dimensional outline of the aforesaid airflow passageway. At least one thin but sturdy cover or skin member is disposed in overlaying relationship about and supported by the structure. 
     The cover member may be maintained in a floating relationship about the support structure with no connection to the structure or it may be attached positively to the support structure at a single area of attachment and remain otherwise in a floating relationship with the structure. The cover member may be an injection molded plastic with internal strengthening ribs or a substantially uniform thickness member produced in a thermo forming process. 
     The accelerators may be stacked vertically with a connecting member therebetween provided at joint areas with labyrinth seals. 
     The support structure may be a lightweight galvanized steel construction, aluminum or a composite carbon material. 
     Preferably, a plurality of cover member sections are mounted on the support structure in adjacent relationship with edge portions overlapping. 
     A presently preferred material for the cover member is polypropylene. 
     The accelerator may include a second wind turbine having an axis parallel with that of the first turbine but mounted on an opposite side of the accelerator. In this case, the airflow passageway bifurcates and follows arcuate paths diverging from a central location to supply each of the turbines with an accelerated airflow. 
     Viewed from the top the accelerator is generally cylindrical with the airflow passageway extending approximately 180 degrees and the turbines 180 degrees apart. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic illustration of a tower comprising a vertical stack of ten accelerators. 
         FIG. 2  is an enlarged schematic of a single accelerator showing its airflow passageway and twin turbines. 
         FIG. 3  is an enlarged view similar to  FIG. 2  but from the top of the accelerator showing the direction of wind flow therethrough. 
         FIG. 4  is 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. 5  is an enlarged view of a joint area between vertically adjacent accelerators. 
         FIG. 6  is an enlarged perspective view of an accelerator showing the support structure. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
     Referring particularly to  FIG. 1 , a tower comprising ten,  10  vertically stacked accelerator and turbine assemblies with a depending anchor  12 . Each accelerator  14  mounts a pair of wind turbines  16 ,  16  each rotatable about a horizontal axis and disposed respectively on opposite sides of the accelerator 180 degrees apart. 
     In  FIG. 2  a single accelerator has an annular recess  18  which is open outwardly to receive the wind and which defines a bifurcated airflow passageway which captures the wind at the front of the unit and divides the flow for delivery to the turbines  16 ,  16 . Due to the curvature of the passageway  18 , the airflow is accelerated in passage from the front of the accelerator to the wind turbines. 
     Arrows  15 ,  15  in  FIG. 3  illustrate airflow through the passageway  18  and the turbines  16 ,  16 . 
     In  FIG. 4 and 6  a support structure for the accelerator is illustrated at  20 ,  20  and  22 ,  22 . Generally u-shaped thin support members are provided in an annular series arrangement to define the three-dimensional outline of the recess  18  which in turn defines the aforementioned air passageway. Connected with the u-shaped members are thin annular members  22 ,  22  which together with the members  20 ,  20  provide a lightweight but sturdy support structure. The u-shaped members  20 ,  20  may take the form of trusses as illustrated. Further structural members comprise mounting plates  30 ,  30  which extend vertically and which support he wind turbines  16 ,  16 . 
     The support members  20 ,  20  and  22 ,  22  may be of galvanized steel, aluminum, or a carbon composite. 
     Supported on and about the support members  20 ,  20  and  22 ,  22  are a plurality of cover member sections  28 . Each of the cover member sections  28 ,  28  takes a generally u-shaped form and the members are arranged in an adjacent relationship with edge portions overlapping. Alternatively, a single large covermember may be provided. 
     Attachment of the cover member to the support structure is limited with a completely floating arrangement between the member and the support structure presently preferred, 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  24  interconnect vertically adjacent accelerators and joint areas between the members  24  and  28  are preferably provided with labyrinth seals  26 ,  26 . 
     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. Preferably the member is formed of polypropylene. 
     From the foregoing it will be apparent that a lightweight but sturdy accelerator construction has been provided with anticipated construction at economic advantage and durability over a long service life.