Abstract:
The embodiment is a venturi front shroud that can be pursed or released to decrease or increase water velocity through the housing of a turbine.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     “Not Applicable” 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     “Not Applicable” 
       REFERENCE TO A MICROFICHE APPENDIX  
       [0003]     “Not Applicable” 
       BACKGROUND OF THE INVENTION  
       [0004]     This patent application follows the provisional application No. 60/472,092 with the filing date May 21, 2003, titled, “Means to increase water velocity through a hydro electric turbine”.  
         [0005]     The method of using a venturi to increase the velocity of a water flow is old. The embodiment has the following aspects which the inventor believes are new. 
        1) The front shroud is flexible (collapsible) on demand.     2) The front shroud can be pursed (drawn) together to stop water from flowing through it and the turbine.     3) The purse line can be released to allow water to flow through the front shroud and turbine.     4) A combination of a flexible front and a rigid rear shroud used together as one unit.     5) The method of pursing a flexible shroud to stop the rotation of a turbine.     6) The method of using a flotation chamber to raise a turbine to the surface to be serviced.        
 
       BRIEF SUMMARY OF THE INVENTION  
       [0012]     One of the problems inherent in a low head (run of the river, tidal, etc.) turbine for producing electricity is the relatively slow water velocity; usually from 1 to 5 knots. This device that incorporates 2 shrouds (one front, one rear) increases the water velocity flowing through the turbine.  
         [0013]     This ability to increase low head water velocities to those of high head applications has inherent advantages of cost, size, efficiency and overall maintainability. Since horsepower output is on an exponential curve with water velocity, it is expedient to keep the blade diameter as small as possible to reach the goal power output. This embodiment does that by the use of shrouds. Overall cost per kilowatt hour is lower when shrouds are used since the shrouds are the least expensive component of the machine.  
         [0014]     The collapsible front shroud, when pursed, provides a rapid means of shutting down the turbine. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0015]      FIG. 1  shows the front and rear shroud with the turbine section between. The cables to the flotation chamber are cut at match line (A).  
         [0016]      FIG. 2  shows the flotation chamber with anchor line. The cables to the shroud are cut at match line (A). 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]     As the water flows through front shroud ( 4 ), it&#39;s velocity and pressure increases. When the flow enters turbine housing ( 1 ), it has reached maximum velocity and pressure. It is in the area ( 2 ) that the work is being done of rotating the turbine blades. As the water passes through the rear shroud ( 3 ), its velocity and pressure is decreased continually until it merges again with the outside flow.  
         [0018]     The draw line ( 6 ) which passes through all the purse rings ( 5 ) and is attached at one end to the front of the shroud ( 4 ) has the ability when pulled, to purse (draw together) the purse rings ( 5 ) and stop the water flow through the turbine. When the draw line ( 6 ) is released, the shroud ( 4 ) will again open, allowing water to pass through the turbine. The cable ( 7 ) attaches the front shroud ( 4 ) to the flotation chamber ( 8 ).  
         [0019]     The scope angle adjustment ( 9 ) is where the anchor line ( 10 ) is attached to the flotation chamber ( 8 ). By adjusting the attachment point of the anchor line ( 1 ) fore or aft, the scope angle  
         [0020]     The embodiment is designed to be pulled below the water surface by the increased amount of drag created when the turbine is operating. When the turbine is switched off or the front shroud ( 4 ) is pursed, drag will decrease and the entire embodiment will float to the surface of the water body.