Abstract:
An improved waterwheel and methods for its use are provided. In an exemplary embodiment, the waterwheel is an undershot waterwheel utilized for electrical power generation. In another embodiment, the waterwheel may be partially or fully submerged. The waterwheel of the present invention may additionally be utilized to provide potable water, oxygen and hydrogen gases. This Abstract is provided for the sole purpose of complying with the Abstract requirement rules that allow a reader to quickly ascertain the subject matter of the disclosure contained herein. This Abstract is submitted with the explicit understanding that it will not be used to interpret or to limit the scope or the meaning of the claims.

Description:
[0001]    This application claims priority to, and the benefit of the filing date, of U.S. Provisional Application No. 60/915,642, filed May 2, 2007, which is incorporated herein by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention generally relates to waterwheels and, in particular, to the application of waterwheels with improved efficiency to non-polluting energy conversion applications. 
       BACKGROUND 
       [0003]    Waterwheels are used to convert the energy of moving water into rotational energy, which in turn is used to power linear or rotational mass transport apparatus. Historically constructed of wood, conventional waterwheels had two wooden vertical sidepieces supporting a horizontal wooden axle. Rigid vanes, blades or buckets, also fabricated from wood, were mounted radially around the rim of the horizontal axle. Some later designs had pivoting blades. The use of iron components and fasteners became common during the Renaissance. 
         [0004]    There are three general types of waterwheels, the undershot, the overshot, and the breast waterwheel. Of the three, the undershot waterwheel is the oldest variety and was the most commonly used. It was placed so that the water flowed under the wheel, engaging the blades, vanes, or buckets and causing the wheel to turn. The early Egyptians and Persians used it extensively to drive water-lifting devices use for irrigation. 
         [0005]    Although notably inefficient, it was the undershot waterwheel that functioned as the prime mover for running the thousands of sawmills that built early America. It generated mechanical energy for gristmills to grind grain, and carding mills to comb wool, and cutting nails and shingles, and powering machines that turned wood for furniture parts. 
         [0006]    However, conventional undershot waterwheels had the following disadvantages: 
         [0007]    They had high structural mass and weight that contributed to low mechanical efficiency. 
         [0008]    Due to the high structural mass and weight, construction of independent dams, sluices, or penstocks was often necessary to route the water to the waterwheel. 
         [0009]    The blades, vanes or buckets were rigidly attached to the sidewalls and the rotating center shaft. This contributed to the retention of water at certain points of rotation, adding weight and creating inherent drag. 
         [0010]    The materials of construction were prone to corrosion, rot, and general deterioration with the attendant cost of replacement and loss of use. 
         [0011]    Interference by floating and submerged debris caused damage, and loss of use during removal and/or repair. 
         [0012]    Maintenance was time consuming, difficult, and costly. 
         [0013]    The undershot waterwheel did not utilize the full velocity of the moving water. The lack of a bottom plate or horizontal shoe promoted turbulence and allowed substantial water to flow down and under the blades, vanes, or buckets during the power portion of the cycle. 
         [0014]    The lack of a bottom plate or horizontal shoe also contributed to scouring of the streambed. 
         [0015]    Only approximately one-third the side length of the blades, vanes, or buckets was utilized. This limited the pushing and lifting effect of the water. 
         [0016]    Atmospheric drag on the blades, vanes, or buckets when above water level contributed considerably to loss of efficiency. 
         [0017]    The waterwheel has progressed in more modern days, but even these newer machines suffer from some of the aforementioned disadvantages. Therefore, there exists a need for an improved waterwheel and methods of using same. 
         [0018]    Accordingly, it is an object of the present invention to provide a waterwheel apparatus, through the use of fiber reinforced polymers, carbon fiber composites, nano-composites, and other technologically advanced materials, having superior performance properties including high compressive, tensile, and shear strength, durability, and high strength-to-weight ratios. 
         [0019]    It is a further object of the present invention to provide for the incorporation of toughened epoxy resins, improved carbon fiber reinforced plastics, and enhanced carbon/epoxy composites, combined with newly modified nanoparticles, into the design and manufacturing process of the herein described waterwheel apparatus. 
         [0020]    It is a further object of the present invention to provide a waterwheel that is lightweight yet rugged and so versatile that no significant modifications are required for operation in a multitude of conditions, locations, and configurations, and that is easily scaled in size. 
       SUMMARY 
       [0021]    The present invention provides a system, apparatus and methods for overcoming one or more of the disadvantages of conventional waterwheels noted above. In one embodiment, a waterwheel apparatus includes a rotor assembly comprising a plurality of circular partitions, fabricated from engineered plastics, that provide exterior sides and inner separators for a plurality of one-piece flanged rotor shafts. The partitions may have V-belt drive grooves around their circumference. 
         [0022]    In one embodiment, the inboard rotor shafts may have flanges at each end with pre-drilled mounting holes that align with pre-drilled holes in the partitions. The outboard rotor shafts that connect to the exterior of the outboard partitions may have a flange with pre-drilled mounting holes on one end and a splined shaft on the other end. One of the outboard rotor shafts may be fitted with a held-type bearing. The other outboard rotor shaft may be fitted with a floating bearing. 
         [0023]    In another embodiment, multiple hinged rotor blades may be mounted radially between the partitions from the periphery of the rotor shafts to the outer edges of the partitions. The outside edges of the rotor blades may be fitted with spring-loaded water seals. The water seals may be constructed with slots and keepers. The hinged rotor blades may be secured to the partitions with ceramic hinge pins through predrilled holes in the partitions. The partitions may be equipped with forward-swing and backswing energy dampener/stops for the rotor blades. 
         [0024]    In one embodiment, a venturi-type inlet duct may be mounted on the inflow side of the waterwheel. In this embodiment, an elongated inlet duct assembly may be connected to the front of the venturi-type inlet duct. The waterwheel rotor assembly may be suspended over the centerline of a horizontal thrust shoe. The horizontal thrust shoe may be equipped with recessed embeds on both ends for retaining the legs of vertical maintenance towers (“maintenance towers”). The venturi-type inlet duct is secured to the leading bottom edge of the thrust shoe, and to the leading inside edges of the maintenance towers. 
         [0025]    A filtering grill/cleaning rake assembly and a trash storage bin may be mounted on the elongated inlet duct assembly. The maintenance towers may be equipped with lifting frame assemblies. Splined ends of outboard rotor shafts and their respective bearing housings rest in the lifting frame assemblies. Jackscrew assemblies mounted on top of the maintenance towers are configured to raise and lower the lifting frame assemblies. Equipment mounting platforms may be attached to outboard sides of the lifting frame assemblies. 
         [0026]    Enclosing the upper one-half of the rotor assembly is a cover that is split and hinged. For installation sites with vertical or sloped banks, air dams may be mounted on the outboard side of the maintenance towers. For installation sites with sloping sides of a hard material (e.g., concrete, brick, etc.), rotor assemblies may be cantilevered on the outboard sides of the maintenance towers. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0027]    Embodiments of the present invention described herein are illustrated by way of example and not by way of limitation, in the figures of the accompanying drawings, in which: 
           [0028]      FIG. 1A  illustrates a perspective view of a stationary rotor assembly in one embodiment; 
           [0029]      FIG. 1B  illustrates a side view of a double-flange inboard rotor shaft in one embodiment; 
           [0030]      FIG. 1C  illustrates a side view of a single-flange outboard rotor shaft in one embodiment; 
           [0031]      FIG. 2A  illustrates a perspective view of a hinged blade rotor assembly in one embodiment; 
           [0032]      FIGS. 2B and 2F  illustrate a plan view and a side view respectively of a hinged blade assembly in one embodiment; 
           [0033]      FIGS. 2C and 2D  illustrate a water seal assembly in one embodiment; 
           [0034]      FIG. 2E  illustrates a replaceable wear shield in one embodiment; 
           [0035]      FIG. 3  illustrates a side view of a stationary waterwheel apparatus with inlet ducts in one embodiment; 
           [0036]      FIG. 4  illustrates a plan view of a stationary waterwheel apparatus with air dams in one embodiment; 
           [0037]      FIGS. 5A and 5B  illustrate a side and a plan view respectively of a stationary waterwheel apparatus having outboard rotor assemblies with cantilevered blades in one embodiment; 
           [0038]      FIGS. 6A ,  6 B and  6 C illustrate a side, a plan, and a frontal view respectively of a floating waterwheel apparatus in one embodiment; 
           [0039]      FIGS. 7A ,  7 B, and  7 C illustrate a plan, a side, and a frontal view respectively of a tethered submersible waterwheel apparatus in one embodiment; 
           [0040]      FIGS. 8A and 8B  illustrate a side and a plan view respectively of a dual stationary waterwheel apparatus with vertically-mounted rotor assemblies mounted on a pier in one embodiment; 
           [0041]      FIG. 8C  illustrates a plan view of a dual stationary waterwheel apparatus with vertically-mounted rotor assemblies with horizontally opposed intakes mounted on a pier in one embodiment; 
           [0042]      FIG. 8D  illustrates a plan view of a single stationary waterwheel apparatus with a movable vertical rotor assembly mounted to a pier with two directional rack and pinion drive assemblies in one embodiment; 
           [0043]      FIGS. 9A and 9B  illustrate a plan view and a side view respectively of a portable waterwheel apparatus in one embodiment; 
           [0044]      FIGS. 10A and 10B  illustrate a side view and a plan view respectively of a portable floating waterwheel apparatus in one embodiment; 
           [0045]      FIGS. 11A and 11B  illustrate a plan view and a rear view respectively of a waterwheel apparatus with horizontal waterwheel rotor assemblies attached to a central floating object in one embodiment; 
           [0046]      FIG. 12  illustrates a side view of a waterwheel apparatus with wind-assisted hydropower generation in one embodiment. 
           [0047]      FIG. 13  illustrates a process for the generation of oxygen and hydrogen in one embodiment; 
           [0048]      FIG. 14  illustrates a combination gas and electrical power transmission system in one embodiment; and 
           [0049]      FIGS. 15A ,  15 B and  15 C illustrate various views of a tethered cable assembly and a cable cleaning system in one embodiment. 
       
    
    
       [0050]    It will be recognized that some or all of the Figures are schematic representations for purposes of illustration and do not necessarily depict the actual relative sizes or locations of the elements shown. The Figures are provided for the purpose of illustrating one or more embodiments of the invention with the explicit understanding that they will not be used to limit the scope or the meaning of the claims. 
       DETAILED DESCRIPTION  
       [0051]    In the following paragraphs, the present invention will be described in detail by way of example with reference to the attached drawings. While this invention is capable of embodiment in many different forms, there is shown in the drawings and will herein be described in detail specific embodiments, with the understanding that the present disclosure is to be considered as an example of the principles of the invention and not intended to limit the invention to the specific embodiments shown and described. That is, throughout this description, the embodiments and examples shown should be considered as exemplars, rather than as limitations on the present invention. Descriptions of well known components, methods and/or processing techniques are omitted so as to not unnecessarily obscure the invention. As used herein, the “present invention” refers to any one of the embodiments of the invention described herein, and any equivalents. Furthermore, reference to various feature(s) of the “present invention” throughout this document does not mean that all claimed embodiments or methods must include the referenced feature(s). 
         [0052]    Water wheels have been used for a number of years to accomplish many manual tasks. Additionally, waterwheels have been used to generate energy. These waterwheels suffer from a number of limitations that various aspects of the present invention address. 
         [0053]    One embodiment of a stationary waterwheel apparatus  200 , illustrated in  FIG. 1A , includes a plurality of circular partitions, such as partition  20 , that serve as exterior sides and inner separators for one-piece inboard rotor shafts  22  and one-piece outboard rotor shafts  24  as illustrated in  FIGS. 1B and 1C , respectively. In an exemplary embodiment, the partitions  20  may be fabricated from a reinforced plastic additionally strengthened through isogrid stiffening technology as is known in the art. The number of partitions  20  may be site installation dependent. 
         [0054]    The one-piece inboard rotor shafts  22  are flanged on both ends as illustrated in  FIG. 1B . The one-piece outboard rotor shafts  24  are flanged on one end and are equipped with a splined-end rotor drive journal (“drive journal”)  26  on the other end, as illustrated in  FIG. 1C . In one embodiment, the inboard rotor shafts  22  may be a plastic derived from plastic filament winding technology as is known in the art. In one embodiment, the outboard rotor shafts  24  may be a combination of reinforced plastic, derived from plastic filament winding technology. The number of inboard rotor shafts  22  is determined by site installation requirements. 
         [0055]    The partitions  20  are equipped with pre-drilled mounting holes to accommodate installation of the inboard and outboard rotor shafts  22  and  24 . The flanged ends of the inboard and outboard rotor shafts  22  and  24  are also pre-drilled for installation. The flanged ends of the inboard rotor shafts  22  are bolted to the partitions  20 . The flanged ends of the outboard rotor shafts  24  are bolted to the exterior of the outboard partitions  20 . 
         [0056]    The drive journal  26  of the outboard rotor shaft  24  on one side of the stationary waterwheel assembly  200  is fitted with a held-type bearing assembly  28 . The drive journal  26  of the outboard rotor shaft  24  on the other side of the rotor assembly is fitted with a floating bearing assembly  30 . 
         [0057]      FIG. 2A  illustrates a rotor assembly  170  comprising a plurality of hinged rotor blades  32  mounted between partitions  20 . In one embodiment, in order to mitigate water leakage and loss of kinetic energy, each hinged rotor blade  32  may be fitted with spring-loaded water seal assemblies  34  as illustrated in  FIGS. 2B and 2F . As illustrated in  FIGS. 2C and 2D , there is a groove  33  on each of the outside edges of each hinged rotor blade  32 . There are slot-shaped openings  35  that go through the two outside surfaces of the rotor blade  32  and through the groove  33 . Tension springs  37  and water seals  39  are placed in the grooves  33  of the rotor blade  32 . Thru-bolts  41  are inserted through the slots and predrilled openings in the water seals  39  and secured on each side of the rotor blade  32  with nuts and washers. The springs  37  place tension against the water seals  39  and the thru-bolts  41  hold the springs  37  and water seals  39  in place. The slots allow for gradual outward movement (from the spring tension) of the water seal  34  as it wears. 
         [0058]    The inboard edges of the hinged rotor blades  32  that will be closest to the inboard rotor shafts  22  have cylindrical openings on each side into which water-lubricated plastic bearings  36  are installed as illustrated in  FIG. 2B . In one embodiment the hinged blades  32  are fabricated from reinforced plastic additionally strengthened through internal and external isogrid stiffening technology as is known in the art. 
         [0059]    Replaceable wear shields  38 , illustrated in  FIG. 2E , are placed on the partitions  20  in preformed recesses that have a center hole. The hinged blades  32  are mounted to the partitions  20  radially from the periphery of the inboard rotor shafts  22  to the outer edges of the partitions  20 . The hinged blades  32  are secured to the partitions  20  through the wear shields  38  with ceramic hinge pin assemblies  40  as illustrated in  FIG. 2E . As illustrated in  FIG. 2A , forward-swing and backswing energy dampener/stops  42  and  44  may be mounted on the partitions  20  for each hinged blade  32 . 
         [0060]    In one embodiment, as illustrated in  FIG. 1A , waterwheel apparatus  200  may include a horizontal thrust shoe  46  with vertical flow-straightening vanes  48 . As illustrated in  FIG. 3 , the ends of the thrust shoe  46  may be equipped with openings  50  to accept the legs of maintenance towers  52 . In one embodiment, the horizontal thrust shoe  46  may be fabricated from lightweight aggregate and reinforced concrete and the flow-straightening vanes  48  may be reinforced plastic. 
         [0061]    The legs of maintenance towers  52  are attached to the thrust shoe  46  via the openings  50 . In one embodiment, the maintenance towers  52  are fabricated from reinforced plastic structural shapes. Liner guides  64 , which may be, for example, an acetyl copolymer, are installed on the insides of the legs of the maintenance towers  52 . Lifting frame assemblies  66 , comprising boxes with two open sides that house the rotor shaft bearings and housings  28  and  30  of the outboard rotor shaft journals, are fitted inside the liner guides  64  of the maintenance towers  52 . In one embodiment, the lifting frame assemblies may be fabricated from reinforced plastic structural shapes. Equipment mounting platforms  68  are secured to the outboard sides of the lifting frame assemblies  66 . Jackscrew assemblies  70  are secured to the tops of the maintenance towers  52 . Screw shafts  172  of the jackscrew assemblies  70  are secured to jackscrew gear motors (not shown) and to the lifting frame assemblies  66 .  FIG. 3  illustrates the rotor assembly  170  in its working (lowered) and parked (raised) positions. 
         [0062]    A venturi-type inlet duct  54  is fitted to a groove (not shown) on the leading edge of the thrust shoe  46  and secured to the legs of the maintenance towers  52 . An elongated inlet duct  56 , with internal flow-directing vanes (not shown), is attached by a flange  58  to the front of the venturi-type inlet duct  54 . A filtering grill/cleaning rake assembly  60  and a debris storage bin  62  may be installed on the front and top, respectively, of the elongated inlet duct  56 . Filtering grill/cleaning rake assembly  60  may include a continuous loop filtering/cleaning rake screen  61  engaged with an upper axle  63  and a lower axle  65 , which may be selectively engaged with the rotor assembly  170  to provide motive power. When engaged, the continuous loop filtering/cleaning rake screen  61  continuously filters out debris from the water flow and transports the debris to the debris storage bin  62 . 
         [0063]    The waterwheel rotor assembly  170  may be positioned over the centerline of the horizontal thrust shoe  46  and placed against the venturi-type inlet duct  54 . The housings of the held-type and floating bearings  28  and  30  on the outboard rotor shafts  24  rest on the lifting frame assemblies  66 . Housings for bearings  28  and  30  are bolted to the lifting frame assemblies  66 . 
         [0064]    The jackscrew assemblies  70  mounted on the maintenance towers  52  are used to raise and lower the lifting frame assemblies  66  on which the waterwheel rotor assembly  170  is supported. In the raised position, the rotor assembly  170  is accessible for maintenance. The lowered position can be adjusted so that the rotor assembly  170  is at an appropriate operating depth for the water source. The top half of the rotor assembly  170  is fitted with a double-hinged split cover  72  that is secured to the lifting assemblies  66 . The hinged cover  72  provides a personnel safety guard, protection from wind, and spray containment. 
         [0065]    The inlet ducts  54  and  56 , on the inflow side of the rotor assembly, channel and direct the water flow down to the hinged blades  32 . The flow-straightening vanes  48  of the horizontal thrust shoe  46  also serve to stabilize and direct the inflow. 
         [0066]    The hinged blades  32  interface with the incoming water creating torque on the rotor shafts  22  and  24 , and the rotor assembly  170  begins rotating. The main held-type bearing  28 , in which one of the outboard rotor shafts  24  is encased, supports and stabilizes the rotor assembly  170  during rotation. The floating bearing  30  on the other outboard rotor shaft  24  allows for horizontal movement of the rotor assembly during rotation. 
         [0067]    As the hinged blades  32  enter and leave the water they settle on the energy dampener/stops  42  and  44  at specific points of rotation determined by the radial length of the hinged blades  32  and the positions of the energy dampener/stops  42  and  44 . When the hinged blades  32  fully interface with the incoming flow, they are held against the forward-swing dampener/stops  42  by the water&#39;s force. As rotation continues, the hinged blades  32  leave the water and settle on the backswing dampener/stops  44 . The spring-loaded water seals  34  ensure minimal water leakage through the hinged blades  32 , and increase the generation of torque. 
         [0068]    Rotational speed continues to increase as each subsequent set of hinged blades  32  moves into position. The kinetic energy provided by the moving water and rotation of the rotor assembly  170  is transferred to the inboard and outboard rotor shafts  22  and  24  where it is converted into mechanical energy. 
         [0069]    The water-lubricated plastic bearings  36  and ceramic hinge pins  40  facilitate freedom of movement of the hinged blades  32  and keep them securely attached to the partitions  20 . The replaceable wear shields  38  mitigate wear of the partitions. 
         [0070]    For use in earthen or vertical concrete-banked watercourses, air dams  74  may be installed on the bank sides of the maintenance towers, as illustrated in  FIG. 4 . The air dams may be fabricated, for example, from a rubber/plastic impregnated cloth with UV protection. When installed, the air dams  74  function to minimize both the loss of water along the sides of the maintenance towers  52 , and to reduce erosion of earthen banks. 
         [0071]    If the waterway is a hard material, such as concrete, brick, etc., and the banks are sloping, rotor blades  76  that cantilever from the outboard sides of the maintenance towers  52  may be installed on the waterwheel apparatus  200  as illustrated in  FIG. 5A  and  FIG. 5B . When installed, the cantilevered rotor blades  76  take advantage of the full breadth and depth of the water flow, and negate the need for air dams and vertical stationary concrete retaining structures. In some embodiments, the cantilevered blades may be on only one side, with an air dam  74  on the other. 
         [0072]      FIGS. 6A ,  6 B and  6 C illustrate a side view, a plan view and a frontal view, respectively, of a floating waterwheel apparatus  600 .  FIGS. 6A and 6B  illustrate the floating waterwheel apparatus  600  with pontoons  80  attached by cross-mounting assemblies  82  to the maintenance towers  52 . In this embodiment, the pontoons  80  keep the rotor assembly  170  afloat. In other respects, the operation of the floating waterwheel apparatus  600  is similar to that of the stationary waterwheel apparatus  200 . Jackscrew assemblies  70  are installed on top of the maintenance towers  52  and screw shafts  172  are secured to lifting frame assemblies  66 . A horizontal thrust shoe  46  is installed beneath the rotor assembly  170  and attached to the legs of the maintenance towers  52 . The thrust shoe  46  for the floating waterwheel apparatus  600  may be fabricated from reinforced plastic and structural closed cell foam. The top half of the waterwheel rotor assembly may be fitted with a double-hinged split cover  72  that is secured to the lifting assemblies  66 . 
         [0073]    One of the pontoons  80  may be enlarged and sized to compensate for the additional weight of selected driven equipment mounted on the waterwheel apparatus as described in greater detail below. External shells of the pontoons  80  and the cross-mounting assemblies  82  may be fabricated from reinforced plastic additionally strengthened with isogrid stiffening technology as is known in the art. The internal areas of the pontoons  80  and cross-mounting assemblies  82  may be fabricated from closed-cell structural foam, for example. 
         [0074]      FIG. 6A  illustrates a motor-driven rotary filtering screen assembly  84  attached to the elongated inlet duct  56  that covers the water-inflow area. The filtering screen assembly  84  covers additional vertical and horizontal length in order to accommodate a horizontal manifold of a pressurized water backwash system. Two pressure sensors (not shown) are installed in the elongated inlet duct  56 . One is located upstream of a filtering screen  94  inlet and the other is located on the downstream side of the filtering screen  94 . The pressure sensors installed in the elongated inlet duct determine the pressure differential between the filtering screens. When a predetermined pressure differential is exceeded, an on-board computer activates a screen wash pump, which can be driven hydraulically, electrically, mechanically or pneumatically, and the drive mechanism activates a full 360° rotating wash cycle. When the screen drive mechanism shuts down, the pressure sensors resample the flow through the screens. If the pressure differential again exceeds the pre-determined value, another full cycle and backwash occurs. If after three full cycles the differential is still above the pre-determined value, the on-board computer shuts the rotary filtering screen assembly down and transmits a remote radio alarm that maintenance intervention is required. As the filtering screen passes over the nozzles of the backwash system, accumulated material is washed from the screen and carried away by the water flow. 
         [0075]    Mounted to the leading edge of the elongated inlet duct  56  is a horizontal driven shaft  90  with a sprocket on each end. An identical freewheeling shaft  92  is mounted on the bottom of the elongated inlet duct  56 . Driven shaft  90  and freewheeling shaft  92  are similar in operation to axles  63  and  65  described above. The sprockets fit into pre-formed drive slots on each side of the filtering screen  94 , which is similar to filtering screen  61  described above. The shafts  90  and  92  are secured to the elongated inlet duct  56  via mounted bearing housings (not shown). 
         [0076]    The backwash system includes a series of backwash nozzles, a horizontal manifold, a screen wash pump, and a screen drive motor. Such components are known in the art and, accordingly, are not described in detail. The backwash system is mounted between the bottom of the motor-driven shaft  90  and the top of the elongated inlet duct  56 . The backwash system runs the full length of the elongated inlet duct  56 . 
         [0077]    The rotary filtering screen assembly  84 , which may be installed at a 45° angle, keeps the rotor assembly free of debris. As the filtering screen  94  passes over the nozzles of the backwash system, accumulated material is washed from the screen  94  and is carried away by the water flow beneath the waterwheel apparatus  600 . 
         [0078]    As illustrated in  FIG. 6C , yoke attachment ears  100  are installed on the outboard and lower sides of the vertical maintenance towers  52 .  FIG. 6B  illustrates a Y-shaped rigid yoke assembly  102  with a crossbar  103  at the lower V points. Yoke assembly  102  may be attached to the yoke attachment ears  100 . Both of the Y legs may be hollow to accommodate controls, power cables, and/or communication cables. In one embodiment, as illustrated in  FIG. 6A , the yoke assembly  102  has a vertical-drop leg  104  that ensures there will be no interference with the incoming water flow. The yoke assembly  102  may be fabricated from reinforced plastic and carbon fiber, for example. 
         [0079]    As illustrated in  FIGS. 6A and 6B , a surge suppressor spring assembly  106  and a tether cable  108  are secured to a 360° swivel at the end of the yoke assembly  102 . The tether cable may be a single-purpose tether configured to anchor the floating waterwheel apparatus  600  in the watercourse, or multi-purpose tether. A single-purpose tether may be fabricated from low-stretch braided nylon and/or various carbon fibers and polymer-based materials. Multi-purpose tethers may include integrated cables for transporting electrical power generated by the waterwheel apparatus, instrument power and control cable systems, air hoses, buoyancy chambers, and/or communication cables. Preferably, steel cables would be used for multi-purpose tethers. Multi-purpose tethers may also be fitted with guide and drive rails to accommodate a remote controlled tether-cleaning mechanism as described below. 
         [0080]    The yoke assembly  102  maintains stability for the entire assemblage and serves as an anchor and pivoting point for the surge suppressor spring assembly  106  and tether cable  108 . The surge suppressor spring assembly  106  serves as a moderating influence over movement of the waterwheel apparatus  600  caused by water surge. The tether cable  108  acts as a link between the waterwheel apparatus and its anchor point and as a platform for the tether cleaner. 
         [0081]    A remote controlled maneuvering/parking rudder assembly  98  is mounted to the stern of each pontoon  80  and controlled via an on-board computer. Rudders  98  may be used in navigable rivers and waterways where barges, ships, and recreational craft navigate. When the on-board computer sends a signal to the rudders  98 , the rudders  98  are programmed to move the floating waterwheel apparatus  600  out of the main current into shallow water. This allows free unobstructed access of the main current to commercial and recreational use. 
         [0082]    An additional signal to the rudder assemblies  98  returns the floating waterwheel apparatus  600  back to the main current. When the on-board computer receives a signal that indicates an operating or maintenance problem exists, the rudders again come into play to move and park the apparatus in a shallow area until the problem is resolved. 
         [0083]      FIGS. 15A and 15B  illustrate a side view and a plan view, respectively, of a tethered cable cleaning mechanism (“cable cleaner”) in one embodiment, and  FIG. 15C  illustrates one embodiment of a tethered cable assembly on which the cable cleaner may operate to keep the tethered cable assembly free of debris and marine growth. The tether  108  is encased in a tether buoyancy chamber  144  that serves as a buoyancy compensator. An armored shielding cover  148  surrounds the tether  108  and tether buoyancy chamber  144 . The tether buoyancy chamber  144  provides the cable cleaner mechanism with the ability to surface, descend, and hover. 
         [0084]    The armored shielding cover  148  may be fitted with two horizontally opposed cutting drive mounting ears  146  and one top-mounted cable cleaner blade groove  162 . The cutting guide mounting ears  146  are for mounting the cable cleaner mechanism on the tether  108 . A foliage cutter blade groove  162  functions as a shear point between the serrated cutter blades  164  of the cable cleaner mechanism. The undersides of the cutting guide mounting ears  146  are notched to accept the cable cleaner drive sprockets  152  that are on the cable cleaner mechanism. The cutter drive sprockets  152  propel the movement of the cable cleaner mechanism up and down the tether  108 . 
         [0085]    Roller guide mounting pulleys  150  secure the cable cleaner mechanism to the tether  108 . Ballast tanks  166  keep the cable cleaner mechanism level. The interior of the armored shielding cover  148  may also contain, but is not limited to, communication/control cables  154 , an emergency supply gas hose  156 , an internal power control cable  160 , and power distribution cables  158 . 
         [0086]    In one embodiment, when the cable cleaner mechanism receives a signal from an on-board waterwheel computer that the rotor assembly is not operating or generating torque, the cable cleaner mechanism parks halfway between the bottom and the surface. During operation of the waterwheel rotor assembly the cable cleaner mechanism is programmed to descend and hover just off the bottom. This prevents the buoyant tether  108  from floating on the surface and interfering with operation of the waterwheel rotor assembly. An emergency recovery snorkel system  168  may be mounted on the top of the cable cleaner mechanism. 
         [0087]      FIGS. 7A ,  7 B and  7 C illustrate side view, a plan view and a frontal view, respectively, of a submersible waterwheel apparatus  700  with two submersible pontoons  110  attached by two cross-mounting assemblies  82  to the vertical members of the maintenance towers  52 . In one embodiment, one of the pontoons  110  may be enlarged and sized to compensate for the additional weight of selected driven equipment attached to the submersible waterwheel apparatus  700 . Inside the pontoons  110  may be ballast/trim tanks  112  controlled by an on-board computer. The external shells  110  of the pontoons and cross-mounting assemblies  82  may be fabricated from reinforced plastic/carbon fiber and additionally strengthened through isogrid stiffening technology. The ballast/trim tanks  112  may be fabricated from reinforced plastic and carbon fiber composites. 
         [0088]      FIG. 7B  illustrates a motor-driven rotary filtering screen assembly  84  attached to an elongated inlet duct  56  that covers the entire water-inflow area. Filtering screen assembly  84  has been described above in detail with respect to the floating waterwheel apparatus  600 . The filtering screen assembly  84  covers additional vertical and horizontal length in order to accommodate the horizontal manifold of a pressurized water backwash system such as the backwash system described above with respect to the floating waterwheel apparatus  600 . 
         [0089]    A remote controlled maneuvering/parking rudder assembly  98  may be mounted to the stern of each pontoon  110  and activated via an on-board computer in the same manner as the remote controlled maneuvering/parking rudder assembly  98  attached to pontoons  80  of the floating waterwheel apparatus  600  described above. 
         [0090]    Yoke attachment ears  100  are installed on the outboard and lower sides of the vertical maintenance towers  52 . A yoke assembly  102 , identical to the assembly for the floating waterwheel apparatus  600 , is Y-shaped and rigid with a crossbar at the lower V points. The yoke assembly  102  may be attached to the yoke attachment ears  100 . The Y-shaped yoke assembly  102  maintains stability for the entire waterwheel apparatus and serves as an anchor and pivoting point for the surge suppressor spring assembly  106  and tether cable  108 . Both of the Y legs of the yoke may be hollow to accommodate instrument control cables, power cables, and/or communication cables as described above. In one embodiment the yoke assembly  102  has a vertical-drop leg  104 , as illustrated in  FIG. 6 , that ensures there will be no interference with the incoming water flow. 
         [0091]      FIG. 7A  illustrates pivoting stabilators  116  that are mounted near the top of each vertical maintenance tower  52  of the submersible waterwheel apparatus  700 . The pivoting stabilators  116  may be controlled by an on-board computer to control horizontal axis roll and pitch. Optional, the stabilators  116  may be replaced with wings and ailerons as is known in the art. In one embodiment, the stabilators  116  may be fabricated from reinforced plastic. 
         [0092]      FIG. 7B  illustrates a 180° closed-end gas-tight clamshell cover  78  that horizontally covers the rotor assembly  170  between the maintenance towers  52 . In one embodiment, the clamshell cover  78  is hinged only on one side. The closed-end gas-tight clamshell cover  78  maintains a gas and water-free environment for the top 180° of the rotor assembly  170 . This chamber allows the blades  32 , either pivoting or fixed, to move through the upper area unimpeded by drag from water.  FIG. 7B  also illustrates the rotor assembly  170  in both its raised and lowered positions. 
         [0093]      FIGS. 7B and 7C  illustrate an emergency recovery snorkel system  118  on the top of the maintenance tower  52 . Snorkel system  118  may include a radio communication antenna, a red rotating beacon, an air activated float, a recovery air hose, and a lifting cable that can be stored on a rotary reel attached to the rotor assembly  170 . The emergency recovery snorkel system  118  is a backup system to recover the submersible waterwheel apparatus  700  in case buoyancy is lost. 
         [0094]    Similar to the waterwheel apparatus described above, submersible waterwheel apparatus  700  includes a horizontal thrust shoe  46  installed beneath the rotor assembly  170  and attached to the legs of maintenance towers  52 . For the submersible waterwheel apparatus  700 , the thrust shoe  46  may be fabricated from reinforced plastic and structural closed cell foam. 
         [0095]    The operation of the submersible waterwheel apparatus  700  is essentially the same as that of the stationary waterwheel apparatus  200 . The pontoons  110  with the ballast and trim tanks  112  receive input from the on-board computer to reach and maintain various operating depths, maintain buoyancy, and to keep the rotor assembly  170  horizontally level at operating depth. They may also serve to raise the rotor assembly to the surface for maneuvering and parking operations as described above. 
         [0096]    The construction and operation of the rotary filtering screen assembly  84  illustrated in  FIG. 7B , is likewise similar to that of the rotary filtering screen assembly described above, as are the remote controlled maneuvering/parking rudder assemblies  98  attached to the pontoons  110  to provide for controlled positioning of the submersible assembly in the current at operating depth. 
         [0097]    The ballast/trim tanks  112  in the pontoons  110  function in concert with the rudders  98  when a signal is sent from the on-board computer to move the submersible waterwheel apparatus  700  out of the main current. The ballast/trim tanks  112  raise the submersible unit to the surface. Then, the rudders  98  act to move the submersible waterwheel apparatus  700  into shallow water. This allows free unobstructed access of the main current to commercial and recreational use. With additional input from the on-board computer, the rudders  98  return the submersible waterwheel apparatus  700  back to the main current, and the ballast/trim tanks  112  dump and return the submersible waterwheel apparatus  700  back to operating depth. 
         [0098]      FIGS. 8A and 8B  illustrate a side view and a plan view, respectively, of a dual stationary vertical waterwheel apparatus  800  with rotor assemblies  170  mounted vertically (i.e., having a vertical axis of rotation) on a single concrete pier  174 . The rotor assemblies  170  are secured to the pier  174  vertically by rack and pinion drive assemblies  114 . The outboard rotor shafts  24  at the bottom of the vertical rotor assemblies  170  are equipped with water-lubricated bearings (not shown) as are known in the art. The outboard rotor shafts  24  at the top of the rotor assemblies  170  are equipped with Kingsbury thrust bearings (not shown) as are known in the art. The bearings on the upper edges of the hinged rotor blades  32  of the rotor assemblies  170  are water-lubricated bearings (not shown) as are known in the art. The bearings on the lower edges of the blades  32  are pre-lubricated sealed thrust type mounted carrier bearings (not shown) as are known in the art. The rotor assemblies  170  may be equipped with rotating filter screen assemblies  84 , described above. The lower ends of the rotor assemblies may be equipped with a ballast tank. Thrust shoes  46  can be installed in a vertical position and attached to the legs of maintenance towers  52 . A clamshell cover  78  may be installed vertically over each rotor assembly  170 . 
         [0099]    The operation of the dual stationary vertical waterwheel apparatus  800  is essentially the same, except for the vertical mounting position of the rotor assemblies  170 , as that of the stationary horizontal waterwheel apparatus  200 . The rack and pinion drive assemblies  114  allow the rotor assemblies  170  to move vertically. The racks of the rack and pinion drive assemblies  114  are mounted vertically to the tops of lifting frame assemblies  66 . Motor-driven pinion gears of the assemblies  114  are mounted on top of the maintenance towers  52 . 
         [0100]      FIG. 8C  illustrates a dual stationary vertical waterwheel apparatus  850  having vertical dual rotor assemblies  170  with horizontally opposed rotating filter screen assemblies  84  mounted on a single pier  174 . This type of installation may be used in dual-direction flow environments such as tidal flows. The rotor assemblies are secured to the pier  174  vertically by rack and pinion drive assemblies  114 . In other respects, the construction and operation of waterwheel apparatus  850  is the same as that of waterwheel apparatus  800 . 
         [0101]      FIG. 8D  illustrates a single stationary vertical waterwheel apparatus  875  with a single rotor assembly  170  mounted vertically to, and movable 180 degrees around, a pier  174 .  FIG. 8D  illustrates the rotor assembly  170  at its two extreme positions, 180 degrees apart. Attached to the pier are two rack and pinion drive assemblies  114 . One drive assembly  114  is installed horizontally and the other drive assembly  114  is installed vertically. Operation of the single stationary vertical waterwheel apparatus  875  is essentially the same as that of the dual stationary vertical waterwheel apparatus  800 , except for the movable rotor assembly  170 . This type of installation may operate in dual-direction tidal flows. The horizontal motor-driven rack and pinion drive assembly  114  moves the rotor assembly horizontally into opposing 180° directions to accommodate changes in tidal flow direction. The vertical motor-driven rack and pinion drive assembly  114  moves the rotor assembly vertically to accommodate changes in tide levels. Computer directional-sensing flow controls are programmed and actuated by flow direction. This keeps the rotor assembly&#39;s intake positioned into the incoming flow at all times. 
         [0102]      FIGS. 9A and 9B  illustrate a side view and a plan view, respectively, of a portable waterwheel apparatus  900 . The rotor assembly  170  of the portable waterwheel apparatus  900  is of the same design as the rotor assembly of the horizontal stationary waterwheel apparatus  200 , with the following possible exceptions: 1) there may be no maintenance towers; 2) the assembly may have hand leveling mechanisms  130  and landing pads  132 ; 3) The assembly may have a foldable and collapsible inlet grill  134 ; 4) The assembly may have a belt-driven vertically mounted generator  176  with a foldable support frame  136 . The operation of the portable waterwheel apparatus  900  is essentially the same as the operation of the horizontal stationary waterwheel apparatus  200 . 
         [0103]      FIGS. 10A and 10B  illustrate a plan view and a side view, respectively, of a portable floating waterwheel apparatus  1000 . The design and operation of the portable floating waterwheel apparatus  1000  is basically the same as the portable waterwheel apparatus  900 , except that: 1) the assembly may float on two attachable air-filled pontoons  138 ; 2) the assembly may have a manual rudder system  140 ; 3) the assembly may have an attached yoke and tether system  142 ; and 4) the assembly may not have hand leveling mechanisms or landing pads. 
         [0104]      FIGS. 11A and 11B  illustrate a rear view and a plan view, respectively, of a waterwheel apparatus  1100  having horizontal rotor assemblies  170  attached to a central floating object  176  that may be a barge, a structural foam filled pontoon, or other floating object. The operation and configuration of the rotor assemblies  170  are essentially the same as the horizontal floating rotor assemblies  170  described above in conjunction with other embodiments of waterwheel apparatus. 
         [0105]    Undershot waterwheels as described herein may provide pollution-free production of either electrical or direct hydrokinetic shaft-driven energy for applications including, but not limited to: reverse osmosis desalination of water; production of hydrogen and medical grade oxygen by electrolysis; utilization of hydrogen and oxygen gases; point-to-point multi-purpose energy transport; conversion of residual heat to steam; sequestering carbon dioxide; wind-assisted hydrokinetic energy generation and deep water cooling. Each of these applications is described briefly below. In the following descriptions, the platforms upon which the applications are performed are referred to as barges for the sake of simplicity and convenience. It will be appreciated that the applications may be implemented in or on one or more of the platforms described herein, including stationary platforms, floating platforms, submersible platforms and fixed and floating portable platforms. 
         [0106]    In one embodiment multiple waterwheel rotor assemblies and a single or multiple barges of appropriate design may be tethered to the ocean floor to convert ocean currents or tidal flows to rotational energy. To utilize direct shaft-driven hydrokinetic energy, positive displacement pumps may be mounted on the rotor shafts of the waterwheels. Multiple desalination units can be mounted on the barge(s). Multiple cylindrical tanks may be secured to the underside of the barge(s). High-pressure hoses may be run from the discharges of the positive displacement pumps to the intakes of the desalination units. Internally, the desalination units may contain long tubes that are divided inside by semi-permeable membranes. 
         [0107]    The positive displacement pumps can be activated by the rotation of the rotor assemblies, pumping seawater and increasing the pressure on the seawater side of the membranes. Because of the filtration level of the membranes, the pressure from the positive displacement pumps causes water molecules to flow through the membrane but does not allow salt molecules through. Pores in a membrane can vary, for example, from 1 to 50,000 angstroms depending on the desired level of filtration. The smallest pore size may be used for reverse osmosis “hyperfiltration.” 
         [0108]    In one embodiment, if the salinity of the water in the filters reaches a predetermined high limit, a computer may be pre-programmed to initiate a flush of the membranes. The highly saline water and the residual brine from previous operations are discharged to the ocean. High pressure hoses attached to the desalination units can either deliver the desalinated water directly to shore or fill tanks on barges or other water vessels for transport. 
         [0109]    An alternative to the aforementioned desalination process is a photochemical desalination process that may be used in lieu of or in addition to the reverse osmosis process. Both processes can be energized by hydrokinetic power provided by embodiments of the waterwheel apparatus described herein. 
         [0110]    In one embodiment, as illustrated by the flow diagram of  FIG. 13 , hydrogen and oxygen gases may be produced by electrolysis. In one configuration, there may be tanks on the barge(s) that can be equipped with an inside barrier wall that divides the tanks into compartments. The barrier stops short of the bottom of the tank. A high-pressure hose pumps desalinated water through a demineralizer and into the tanks, filling them. Inside and at the top of the tanks, on each side of the barrier, are electrodes—an anode (positive) on one side of the barrier and a cathode (negative) on the other. The electrodes are connected to opposite poles of a source of direct current powered by the waterwheel. Each electrode attracts ions of the opposite charge. Therefore, positively charged ions (cations) move toward the cathode, and negatively charged ions (anions) move toward the anode. 
         [0111]    The electric current disassociates water molecules into hydroxide (OH − ) and hydrogen (H + ) ions. At the cathode, hydrogen ions (H+) accept electrons in a reduction reaction that forms hydrogen gas. At the anode, hydroxide ions (OH−) undergo an oxidation reaction and give up electrons to the anode to complete the circuit and form water and oxygen gas. Oxygen gas can now be drawn off one side of the tanks and hydrogen gas from the other. The gases may then be transferred into their respective storage tanks beneath the barge(s) via high-pressure hoses and/or piping. The gases can then be off-loaded to other barges or floating vessels, in gaseous or liquid form, for transport. 
         [0112]    The hydrogen and oxygen gases can be utilized to generate electrical power through onboard equipment such as fuel cells, gas-powered turbines, and/or modified reciprocating engines to power the various operating systems during slack tides. The purity of both gases significantly extends fuel cell life cycles and vastly minimizes required maintenance. This significantly lowers the operating costs of fuel cells in the production of renewable electric power. 
         [0113]    These gases may also be used to fuel modified reciprocating engines and gas turbines. Utilization of pure oxygen in the combustion process eliminates the creation of nitrous oxides that are the precursor gas that creates smog. The electric power generated may also be sent ashore via underwater power lines to be marketed. 
         [0114]    In one embodiment, as illustrated in  FIG. 14 , both electrical power and hydrogen gas may be sent point-to-point via a multiple-purpose transportation pipeline  178 . The pipe may be scaled to size to accommodate a large internal electrical conductor in the center. Ceramic insulators may separate areas through which the hydrogen gas will flow. Thus, electrical power and hydrogen gas may be transported simultaneously. Further, the hydrogen gas can be tapped at various points and run through a non-polluting electrical generating fuel cell. 
         [0115]    The residual heat generated from the fuel cell can be converted to steam and marketed to steam-dependent industries along the pipeline, e.g., food processing plants. Residual heat passing over a bank of tubes that are filled with pressurized water transforms the water in the tubes to steam. The steam may then be piped to a steam turbine attached to an electric generator. Alternatively, the steam can be run through a steam turbine to generate additional non-polluting electrical power. 
         [0116]    One embodiment can effectively inject and safely store carbon dioxide (CO 2 ) at the bottom of the ocean. As the negatively buoyant CO 2  encounters the high pressure in the low temperatures at depths greater than 3000 m, the gas turns into a dense liquid unable to rise to the ocean&#39;s surface. Its inherent properties lead to the formation of crystals, known as CO 2  hydrides, which collect into a solid, stable layer from under which the gas cannot escape. The CO 2  may be condensed and pressurized at other facilities. The CO 2  is delivered to the floating waterwheel apparatus, equipped with a positive displacement pump, energized by ocean currents and wind. The condensed CO 2  is pumped to the bottom of the ocean via a weighted submersible discharge hose on the waterwheel apparatus. 
         [0117]    As illustrated in  FIG. 12 , fixed blade horizontal wind turbines, such as wind turbine  180 , with spring-loaded air seals and venturi shaped inlets, can be mounted on the foredecks of a floating waterwheel rotor assemblies. The horizontal wind turbine drive shafts can accommodate electric generators, process pumps, compressors, etc. The addition of pulley and belt systems, and/or chain and sprocket assemblies between the fixed blade horizontal wind turbine  180  and the waterwheel rotor assemblies  170  can also increase the power output of the waterwheel rotor assembly. 
         [0118]    Alternatively, installation of positive displacement pumps on the drive shafts of the horizontal wind turbine, and hydraulic motors on the drive shafts of the waterwheel rotor assemblies, can supply additional power. A hydraulic supply hose could convey the hydraulic energy to the hydraulic motor. This effectively reduces the number of onboard generators needed to one. 
         [0119]    In one embodiment, one or more bull wheels may be mounted on the outboard rotor shafts of the rotor assembly or assemblies. The outer circumference of the bull wheel(s) may be fitted with belt grooves, chain sprocket teeth or spur gearing, for example, to drive various RPM increasing or reducing transmissions and to drive other types of equipment such as electrical generators (e.g., to produce on-board power) and pumps. Such transmissions may have multiple power takeoff points which may be engaged and disengaged with clutches. 
         [0120]    Embodiments of the waterwheel apparatus may be used to power deep-water pumps to send cold water to shore installations via a cooling pipe. The cold water could be circulated through heat-exchangers in cooling systems in buildings and then discharged back into the originating body of water. This type of cooling system would replace chiller systems that are currently driven by polluting electrical power sources, thereby reducing operating costs and the carbon footprints of buildings. In parallel, electricity could be conveyed to shore with the cold water to power various pumps and fans in the buildings&#39; heating, cooling and ventilating systems. This combination of pollution-free energy would result in buildings with no carbon footprint at all. 
         [0121]    Thus, it is seen that an improved waterwheel and methods for its use are provided. One skilled in the art will appreciate that the present invention can be practiced by other than the above-described embodiments, which are presented in this description for purposes of illustration and not of limitation. The specification and drawings are not intended to limit the exclusionary scope of this patent document. It is noted that various equivalents for the particular embodiments discussed in this description may practice the invention as well. That is, while the present invention has been described in conjunction with specific embodiments, it is evident that many alternatives, modifications, permutations and variations will become apparent to those of ordinary skill in the art in light of the foregoing description. Accordingly, it is intended that the present invention embrace all such alternatives, modifications and variations as fall within the scope of the appended claims. The fact that a product, process or method exhibits differences from one or more of the above-described exemplary embodiments does not mean that the product or process is outside the scope (literal scope and/or other legally-recognized scope) of the following claims.