Abstract:
An electric power-generating assembly is disclosed. The assembly includes a sill wall constructed within the bed of the waterway and at least one waterwheel-driven generating unit supported directly downstream of the sill wall. The waterwheel generating unit includes a waterwheel, a chute and an electric generating unit. The electric generator unit is mounted axially within the waterwheel and includes a rotor disposed axially within a stator and drive means operably connecting the waterwheel to the rotor.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This U.S. Patent Application is based upon U.S. Provisional Patent Application Ser. No. 60/069,102, filed Dec. 10, 1997, entitled “WATERWHEEL-DRIVEN GENERATING ASSEMBLY” and U.S. Provisional Patent Application Ser. No. 60/095,437, filed Aug. 5, 1998, entitled “WATERWHEEL-DRIVEN GENERATING UNIT”. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to waterwheel-driven generating assemblies. More particularly, the invention relates to waterwheel-driven generating assemblies adapted for application at locations without an existing dam. The invention further relates to a waterwheel-driven generating unit operating in an overshot or pitchback mode and including booster jets directing streams of high pressure water against the buckets of the wheel near their lowest point. 
     2. Description of the Prior Art 
     This invention pertains, in general, to waterwheels containing a speed-increaser gear unit and an electric generator internally contained within the waterwheel. One waterwheel-drive generating unit known to the public is disclosed in the inventors&#39; own U.S. Pat. No. 5,440,175, entitled “Waterwheel-Driven Generating Unit”, to Mayo, Jr. et al., which is incorporated herein by reference. 
     At present and in the recent past, hydroelectric installations using low-head dam sites, such as those typically less than 15 feet when measured vertically from headwater to tailwater, have generally been unable to economically develop commercial power. The limited number of installations of this type which have been developed had either a subsidy, special power rates, very unusual site conditions, or proved to be economic failures. The hydraulic turbines currently being manufactured are usually custom-designed and are very expensive per unit of power output due to their complex designs which require such items as trash racks, flume or penstock, intake gate, speed-increaser and generator, powerhouse, tailrace and possibly other auxiliary equipment. Existing dams are typically most economical to develop but they also require either an opening through or around the dam or a syphon intake. Each of these items adds substantially to the cost. 
     As the inventors&#39; own U.S. Pat. No. 5,440,175 shows, attempts have been made to overcome the limitations of the prior art as discussed above. However, no solution has been provided to address the use of waterwheel-driven generating assemblies at locations having no existing dam. The present invention provides a solution to the need for waterwheel-driven generating units at locations having no existing dam. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to provide an electric power-generating assembly adapted for application at waterway locations without an existing dam. The assembly includes a sill wall constructed within the bed of the waterway and at least one waterwheel-driven generating unit supported directly downstream of the sill wall. The waterwheel generating unit includes a waterwheel, a chute and an electric generating unit. The electric generator unit is mounted axially within the waterwheel and includes a rotor disposed axially within a stator and drive means operably connecting the waterwheel to the rotor. In addition, the chute includes an upstream end pivotally secured to the sill wall and a downstream end supported on the waterwheel, wherein the downstream end of the chute clears the circular path defined by an outer edge of the waterwheel when the waterwheel is rotating. 
     It is also an object of the present invention to provide an electric power generating assembly wherein the downstream end of the chute includes wheels which ride upon the waterwheel. 
     It is another object of the present invention to provide an electric power generating assembly wherein the waterwheel-driven generating unit includes a shroud secured adjacent a downstream side of the waterwheel. 
     It is a further object of the present invention to provide an electric power generating assembly including means for selectively lifting the waterwheel-driven generating unit. 
     It is also an object of the present invention to provide an electric power generating assembly wherein the means for selectively lifting includes a guide frame which selectively raises and lowers the waterwheel to control the volume of water entering the waterwheel. 
     It is another object of the present invention to provide an electric power generating assembly wherein the guide frame selectively lifts the waterwheels between a fully raised position where no water flows onto the waterwheel and a fully lowered position where the waterwheel is inoperative. 
     It is a further object of the present invention to provide an electric power generating assembly wherein components of the electric generating unit are supported by a carriage sealed within the waterwheel, and the carriage may be withdrawn from the waterwheel. 
     It is also an object of the present invention to provide an electric power generating assembly wherein the carriage is supported for movement on a runway rail mounted within the waterwheel. 
     It is another object of the present invention to provide an electric power generating assembly wherein the components include a speed increaser and a generator. 
     It is a further object of the present invention to provide an electric power generating assembly wherein the waterwheel-driven generating unit includes a booster jet. 
     It is also an object of the present invention to provide an electric power generating assembly wherein the waterwheel-driven generating unit operates in an overshot mode. 
     It is another object of the present invention to provide an electric power generating assembly wherein the waterwheel-driven generating unit operates in a pitchback mode. 
     It is a further object of the present invention to provide a waterwheel-driven generating unit wherein the guide frame includes first and second columns coupled to opposite ends of the waterwheel. 
     It is also an object of the present invention to provide a waterwheel-driven generating unit wherein the carriage is supported for movement on a runway rail mounted within the waterwheel such that the carriage moves through the watertight door onto an external runway. 
     It is a further object of the present invention to provide a waterwheel-driven generating unit wherein the booster jet includes a spring loaded adjustment sleeve attached to a first end of the booster jet for maintaining the booster jet adjacent the water wheel. 
     Other objects and advantages of the present invention will become apparent from the following detailed description when viewed in conjunction with the accompanying drawings, which set forth certain embodiments of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of the present waterwheel-driven generating assembly installed at a river site. 
     FIG. 2 is a cross sectional view along the line II—II of the waterwheel-driven generating assembly as shown in FIG.  1 . 
     FIG. 3 is a downstream elevation view of the present waterwheel-driven generating assembly. 
     FIG. 4 is a cross sectional view of the waterwheel used in accordance with the present invention. 
     FIG. 5 is a detailed cross sectional view showing one embodiment for the end structure of the waterwheel including trunions. 
     FIG. 6 is an end view showing the lifting framework and hoist mechanism in accordance with the present invention. 
     FIG. 7 is a cross sectional view along the line VII—VII of the lifting framework and hoist mechanism as shown in FIG.  6 . 
     FIG. 8 is a detailed cross sectional view along the line VIII—VIII in FIG. 7 (alternate design, including rollers, to that shown in FIG. 5 ). 
     FIG. 9 is a detailed cross sectional view along the line IX—IX in FIG.  6 . 
     FIG. 10 is a sectional view of an alternate embodiment of the invention showing a waterwheel-driven generating unit operating in the overshot mode and utilizing booster jets having a telescopic sleeve which holds the nozzle to the conduit. 
     FIG. 11 is a sectional view of a further embodiment of the invention showing a waterwheel-driven generating unit operating in the pitchback mode and utilizing booster jets having a hinged joint which holds the nozzle to the conduit. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The detailed embodiments of the present invention are disclosed herein. It should be understood, however, that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, the details disclosed herein are not to be interpreted as limited, but merely as the basis for teaching one skilled in the art how to make and/or use the invention. 
     With reference to FIGS. 1-3, a waterwheel-driven generating assembly  10  adapted for application at locations without an existing dam is disclosed. The waterwheel-driven generating assembly  10  includes an associated control center  12  and walkway  14 . In addition, other necessary accessories may be employed with the waterwheel-driven generating assembly  10 , without departing from the spirit of the present invention. The present waterwheel-driven generating assembly  10  permits application at locations without a dam, where the installation of the waterwheel-driven generating assembly  10  will not cause upstream flooding during normal flow and operating conditions. The present waterwheel-driven generating assembly  10  also permits application at locations without a dam, where the waterwheel-driven generating assembly  10  will not cause any significant increase in the upstream water elevations when the waterwheels are lowered and flood flow occurs. 
     As shown, the waterwheel-driven generating assembly  10  includes first and second waterwheel-driven generating units  16   a ,  16   b  installed on a low concrete sill wall  18 . The sill wall  18  is constructed across a river bed between a first concrete abutment  20  positioned on a first riverbank and a second concrete abutment  22  positioned on the opposite second riverbank. A concrete dividing wall  24  is provided in the center of the river. The concrete dividing wall  24  is positioned and constructed to separate and support one end of each of the first and second waterwheel-driven generating units  16   a ,  16   b . While the disclosed embodiment employs two waterwheel-driven generating units, a single unit or additional units may be employed without departing from the spirit of the present invention. 
     Each waterwheel-driven generating unit  16   a ,  16   b  is provided with a waterwheel, a chute and a shroud. The embodiment disclosed in FIGS. 1-3 includes a first waterwheel-driven generating unit  16   a  including a first waterwheel  26   a , a first chute  28   a  and a first shroud  30   a , and a second waterwheel-driven generating unit  16   b  which includes a second waterwheel  26   b , a second chute  28   b  and a second shroud  30   b.    
     With reference to FIGS. 4 and 5, an embodiment of the first waterwheel  26   a  is disclosed in detail. While the first waterwheel  26   a  is described herein, it should be understood that the second waterwheel  26   b  may be identical. The waterwheel  26   a  is operable between headwater and tailwater and comprises a metal cylinder  32  surrounded by multiple sets of buckets  34 . The buckets  34  are fixedly attached along one edge to the cylinder and are also attached and sealed at each end by an end closure plate  36  and/or intermediate disc  37  (see FIG.  1 ). The waterwheel  26   a  may be constructed in any structurally-rigid length with rigidly-attached intermediate rings and/or discs  37  to increase the rigidity of cylinder  32  and buckets  34 . In fact, the waterwheel  26   a  is constructed in much the same manner as the waterwheel disclosed in the inventors&#39; own U.S. Pat. No. 5,440,175, which is incorporated herein by reference. 
     Internal reinforcing, not shown, may be added as necessary for additional stiffness. Trunnion bearings  38  are centrally-located at each end of the waterwheel and are connected to a lift framework  40  (see FIG. 6) that will be discussed in greater detail below. A watertight door  42  is attached to the flat circular plate  36 . As will be discussed in greater detail below, the watertight door  42  facilitates internal access to the waterwheel  26   a  while preventing the entrance of water and debris. Within the cylinder  32  is a speed-increaser system  44  (see (FIG. 7) directly connected by suitable means to an electric generator  46 . The detailed structures of the speed-increaser system  44  and the generator  46  are disclosed in the inventors&#39; own U.S. Pat. No. 5,440,175, which is incorporated herein by reference. 
     Water flowing over the concrete sill wall  18  (see FIGS. 1-3) is directed onto the first waterwheel  26   a  by the first chute  28   a , while water flowing over the concrete sill wall  18  is directed onto the second waterwheel  26   b  by the second chute  28   b . In use, the first and second chutes  28   a ,  28   b  are each long and high enough to discharge water into the uppermost space between the buckets  34  of the waterwheels  26   a ,  26   b , while also acting as a bottom hinged gate to resist pressure from the water upstream of the waterwheel-driven generating assembly  10 . 
     The first chute  28   a  and the second chute  28   b  are hinged  48  to the top of the concrete sill wall  18  at positions upstream and adjacent the respective first waterwheel  26   a  and second waterwheel  26   b . The first and second chutes  28   a ,  28   b  are pivotally secured to the concrete sill wall  18  such that they respectively move with the first and second waterwheels  26   a ,  26   b . The general structure of the first and second chutes  28   a ,  28   b  is similar to the chute disclosed in the inventors&#39; own U.S. Pat. No. 5,440,175, which is incorporated herein by reference. In addition, each end and lower edge of each chute is provided with a flexible seal  50  (see FIG. 2) that prevents water from breaking past the ends and lower edge of the chute. The surface of the concrete abutment walls  20 ,  22  and  24  are made true and smooth to achieve a watertight seal. 
     While the upstream edges  52   a ,  52   b  of the first and second chutes  28   a ,  28   b  are hinged to the concrete sill wall  18 , the downstream edges  54   a ,  54   b  of the first and second chutes  28   a ,  28   b  are respectively supported on the first and second waterwheels  26   a ,  26   b  by grooved wheels  56  secured to the undersides of the first and second chutes  28   a ,  28   b . The wheels  56  run on the edges of disks  37  formed transversely to the axis of the waterwheels  26   a ,  26   b . The disks  37  are spaced at intervals along the waterwheels  26   a ,  26   b  and are positioned such that the wheels  58  of the chutes  28   a ,  28   b  ride thereon to support the downstream edges  54   a ,  54   b  of the first and second chutes  28   a ,  28   b . In this way, supporting wheels  56  riding on the waterwheels  26   a ,  26   b  at a downstream position, in combination with a hinged mounting at the upstream position, allow the first and second chutes  28   a ,  28   b  to respectively follow the motion of the first and second waterwheels  26   a ,  26   b.    
     As discussed above, each waterwheel-driven generating unit  16   a ,  16   b  is provided with a shroud  30   a ,  30   b  (see FIGS. 2 and 3) positioned by cable substantially along its downstream side. Each shroud  30   a ,  30   b  consists of a curved plate that extends the full length of the waterwheel  26   a ,  26   b . The curved plate also extends vertically downward approximately 90° from about 10° above the horizontal centerline. The curvature has a radius slightly greater than that of the waterwheel. This provides sufficient clearance to prevent the shroud from rubbing the waterwheel when in operation. The shroud  30   a ,  30   b  is pivotally-attached to the outside face of the stationary ring girders  58  (discussed in greater detail below and shown in FIGS. 7 and 8) at each end of the waterwheel  26   a ,  26   b  by a curved box shaped track and steel rollers  76  (see FIG.  8 ). 
     The first and second waterwheel-driven generating units  16   a ,  16   b  are respectively supported by lifting frameworks  40   a ,  40   b ,  40   c ,  40   d  (see FIGS.  2  and  3 ), and an associated guide frame  60  (see FIG.  6 ), designed to selectively raise and lower the waterwheels  26   a ,  26   b  to control the volume of water entering the waterwheels  26   a ,  26   b  from the chutes  28   a ,  28   b . When the waterwheels  26   a ,  26   b  are fully raised, no water flows onto the tops of waterwheels. When the waterwheels  26   a ,  26   b  are fully lowered, the waterwheels  26   a ,  26   b  are protected from flood flows and debris by the chutes  28   a ,  28   b  on the upstream side of the waterwheel-drive generating units  16   a ,  16   b  and the shrouds  28   a ,  28   b  on the downstream side of the waterwheel-drive generating units  16   a ,  16   b . The waterwheel-drive generating units  16   a ,  16   b  are inoperative when in their fully lowered positions. 
     During normal operation, the waterwheel height is adjusted to develop maximum power output for the available discharge in the river. During inspection and maintenance periods, the waterwheels are fully raised to provide access to the electrical and mechanical equipment associated with each waterwheel-drive generating unit. When there is a warning of an impending flood, the waterwheels are fully lowered to protect the wheels and provide minimum obstruction to flood flows. 
     Referring to FIG.  3  and  6 - 9 , the lifting frameworks  40   a ,  40   b ,  40   c ,  40   d , and associated guide frame  60 , are disclosed. The first lifting framework  40   a  disclosed in FIGS. 6-9 is associated with the first abutment  20 . However, a respective lifting framework is provided at each end of both the first and second waterwheel-drive generating units  16   a ,  16   b . As such, a second lifting framework  40   b  is provided adjacent the second abutment  22 , and first and second central lifting frameworks  40   c ,  40   d  are positioned on opposite sides of the central concrete dividing wall  24 . 
     The lifting framework  40   a  includes a pair of cylindrical metal columns  62 ,  64  supporting the guide frame  60 . The metal columns  62 ,  64  are mounted on the concrete foundation slab  66  adjacent to the first abutment  20 , and extend substantially parallel to the first abutment  20 . The columns  62 ,  64  are bolted at intervals to the concrete abutment  20  to provide lateral support. The metal columns  62 ,  64  position the guide frame  60  and the ring girder  58 . The external ring girder  58  is mounted on the guide frame  60  located between the cylindrical metal columns  62 ,  64  to permit vertical movement of the guide frame  60  and the external ring girder  58 , and the waterwheel-driven generating unit  16   a . The guide frame  60  is, therefore, provided with Teflon faced guides shoes  68 , or rollers, which ride around the cylindrical surface of the metal columns  62 ,  64  as the external ring girder  58  is moved up and down on the metal columns  62 ,  64 . 
     The external ring girder  58  includes a stationary support ring  70  (see FIGS. 6 and 8) mounted on the guide frame  60  and a bearing housing  72  rotatably coupled to the stationary support ring  70 . In use, the waterwheel  26   a  is coupled to the bearing housing  72  formed by the waterwheel metal cylinder  32  and closure plate  36  for rotation therewith. The bearing housing  72  includes ball bearings  74  and roller bearings  76  positioned between the stationary support ring  70  and a rotating ring closure plate  36  which is part of the waterwheel  26   a . The bearing housing  72  permits the waterwheel  26   a  to freely rotate as the water flows through the waterwheel-driven unit  16   a.    
     Vertical movement of the external ring girder  58 , with guide frame  60  and the waterwheel-driven generating unit  16   a , is controlled by a multi-part steel wire rope block and tackle  80  (see FIG.  6 ). The wire rope  82  is guided by a series of pulleys  84  leading to an electrically powered winch  86  from both ends of each waterwheel-driven generating unit  16   a  to assure simultaneous operation. In this way, the external ring girder  58  is selectively moved up and down. 
     The external ring girder  58  is connected to an end of a waterwheel  26   a  such that when the waterwheel  26   a  is at the top of its travel (see FIG.  7 ), a watertight door  42  in the end closure plate  36  of the waterwheel  26   a  may be removed and a wheeled carriage  87  (see FIGS.  7  and  9 ), supported by an internal frame  88 , carrying the speed increaser  44  and generator  46  may be withdrawn for inspection and maintenance work. The wheeled carriage  87  is withdrawn with the help of a hand operated winch and wire rope block and tackle (not shown) that can operate in either direction. 
     During operation of the system, the internal frame  88  of the waterwheel  26   a  is supported by the external ring girder  58  at the outboard end and by the first transverse disk  37  at the inboard end. A runway rail  90  is installed at each side of the internal frame  88  to permit withdrawal of the electro mechanical equipment and transfer to a truck or support frame for inspection. As such, the equipment is provided with wheels  92  which ride on the runway rail  90 . With this in mind, the internal framework  88  is designed to both support the weight of the speed increaser  44  and generator  46 , and also to resist the torque applied to the equipment from the rotating waterwheel. 
     The present invention permits waterwheel-driver generating units to be applied at locations on natural rivers and man-made canals where no dam presently exists, but where the installation of such an invention will not cause a significant increase in water level upstream during normal flow and operating conditions. The present assembly also will not cause any significant increase in upstream water elevations when the waterwheels are lowered and flood flow occurs. 
     The present invention also provides a convenient and reliable system for supporting columns from the base of the concrete abutments at each river or canal bank and/or at any intermediate wall for the multi-unit installations. Use of the cylindrical shaped metal columns as both vertical load carrying members and guides in a horizontal direction, provides greater precision of location and assurance of safety factor than use of concrete projections in a remote area. In this way, the present invention employs an external frame able to support each end of a waterwheel and convey the load to the columns while allowing access to the end of the wheel for withdrawal of the electro mechanical equipment housed within the end of the waterwheel. 
     With reference to FIG. 10, and alternate embodiment of the present waterwheel-driven generating unit is disclosed. The disclosed waterwheel-driven generating unit  102  is installed downstream of a check structure in an irrigation canal. The present waterwheel-driven generating unit  102  is designed to be constructed at sights having concrete spillways, such as check structures in irrigation canals. However, the disclosed waterwheel-driven generating unit may be employed in a variety of applications without departing from the spirit of the present invention. The check structure includes removable wooden flash boards  124  located above a concrete spillway  106 . A control center  134  and walkway  110  are associated with the waterwheel-driven generating unit  102 . In addition, other necessary accessories may be employed with the waterwheel-driven generating unit  102 , without departing from the spirit of the present invention. 
     The waterwheel-driven generating unit  102  includes a waterwheel  112  and an adjustable steel chute  114  attached to flashboards  124 . The waterwheel  112  is constructed in much the same manner as the waterwheel disclosed in the inventors&#39; own U.S. Pat. No. 5,440,175. The waterwheel  112  supports a plurality of curved buckets  116  positioned around the perimeter  118  of the waterwheel  112 . The buckets  116  extend radially inwardly from the perimeter  118  of the waterwheel  112  toward the axis  120  of the waterwheel  112 . The buckets  116  each have a concave surface  122  which faces opposite the waterflow direction, such that when water flows into the buckets  116  the buckets catch and hold the water while the waterwheel  112  rotates. 
     The steel chute  114  is attached to a weir  124  on top of the concrete spillway  106  such that the chute  114  may be adjusted to direct the flow of water onto the waterwheel buckets  116  at the top of the waterwheel&#39;s rotation. The general structure of the chute  114  is similar to the chute disclosed in the inventors&#39; own U.S. Pat. No. 5,440,175. The water remains in the buckets  116  until the buckets  116  reach a point near the bottom of the waterwheel&#39;s rotation. At this point, the water falls from the buckets  116  into the canal below the waterwheel. 
     A steel shroud  126  surrounds a 90 degree section of the waterwheel  112  near the lower, downwardly rotating section of the waterwheel  112 . The shroud  126  prevents water from spilling out of the waterwheel buckets  116  until the buckets reach a position at the bottom of the waterwheel&#39;s rotation. The general structure and operation of the shroud  126  is similar to the shroud disclosed in the inventors&#39; own U.S. Pat. No. 5,440,175. 
     In addition to the above features, the waterwheel-driven generating unit  102  includes a steel frame platform  128  which holds a waterwheel  112 , controls  134 , cables  136 , winches  138 , fences  140 , and a roof  142 . The detailed structures of the speed-increaser system  130 , the generator  132  and their respective operation are disclosed in the inventors&#39; own U.S. Pat. No. 5,440,175. 
     Referring to FIG. 10, the disclosed waterwheel-driven generating unit  102  is an overshot mode waterwheel-driven generating unit. The waterwheel-driven generating unit  102  includes six booster jets  144  which direct streams of higher pressure water against the buckets  116  of the waterwheel  112  near the waterwheel&#39;s lowest point of travel. The configuration of each of the six booster jets  144  is identical. As such, although only one booster jet  144  is shown in the drawings, the following detailed description is applicable to each of the booster jets. In addition, although six booster jets are disclosed in the preferred embodiment, one or more booster jets may be employed without departing from the spirit of the present invention. 
     Each booster jet  144  comprises one or more conduits  146  which transports water entering the upper end  148  of the conduit  146  through a control gate  150  located in the plane  152  of the weir  124  on the concrete spillway  106 . The booster jet  144  also comprises an adjustable vertical nozzle  154  located at the lower or downstream end  156  of the one or more conduits  146 . 
     Each conduit  146  is preferably manufactured from steel. The one or more conduits  146  preferably have a total cross-sectional area of approximately one half the vertical sectional area under the waterwheel  112 , and the control gate  150  has an effective water flow preventing area equal to or greater than the cross-sectional area of the conduit. While the preferred dimensions and materials are disclosed herein, it should be understood that the booster jet may vary, somewhat, without departing from the spirit of the present invention. 
     When assembled, the conduit  146  is secured to the sloping upper surface  158  of the concrete spillway  106 . A plurality of steel bolts  160  and other commonly-used fastening hardware components secure the conduit  146  to the concrete spillway  106 , although other suitable fastening methods and apparatuses may be used without departing from the spirit of the invention. 
     The booster jets  144  utilize a first configuration for adjusting the position of the booster jets  144  in relation to the fixed portion of the supply conduit  146 . Adjustment maintains the elevation and direction of the booster jets  144  constant in relation to the position of the bottom of the waterwheel  112 . Although shown with the overshot embodiment, use of this booster jet nozzle configuration is not strictly limited to use with overshot mode waterwheels. 
     The booster jet  144  includes a spring-loaded adjustment sleeve  162  which attaches the first end  164  of the adjustable vertical nozzle  154  to the lower end  156  of the conduit  146 . The adjustment sleeve  162  is a spring-loaded telescopic sleeve which forces the vertical nozzle  154  toward the bottom of the waterwheel  112 . Other spring-loaded sleeve configurations may be used without departing from the spirit of the invention. 
     The vertical nozzle  154  is positioned such that the second end  166  of the vertical nozzle  154  contacts the rim  168  of the waterwheel  112  near the lowest point of travel of the waterwheel  112 . The force provided to the vertical nozzle  154  from the spring-loaded adjustable sleeve  162  keeps the second end  166  of the vertical nozzle  154  in contact with the waterwheel rim  168 , ensuring that the position of the booster jets  144  with respect to the bottom of the waterwheel  112  remains constant. 
     In operation, water flows into the upper end  148  of the conduit  146  through the control gate  150  in the weir  124  above the concrete spillway  106 . Water then flows through the conduit  146  and passes through the vertical nozzle  154  located at the lower end  156  of the conduit  146 . The vertical nozzle  154  directs the stream of high pressure water against the waterwheel&#39;s buckets  116  near the waterwheel&#39;s lowest point of travel. The high pressure stream of water applies a force against the buckets  116  in addition to, and in the same direction as, the force applied to the buckets  116  simultaneously by the overshot water flowing against the buckets  116  at the top of the waterwheel&#39;s rotation plus the water weight acting on the downstream side. Thus, the booster jets  144  increase the amount of water pressure acting on the waterwheel  112 , thereby increasing the cost effectiveness of the waterwheel-driven generating unit  102 . Alternatively, the booster jets may be operated independent of water flowing over the waterwheel. 
     FIG. 11 shows a further configuration of the waterwheel-driven generating unit  202  wherein the waterwheel&#39;s direction of rotation is reversed. The waterwheel  212  operating in this mode is known to be operating in a pitchback mode. The basic configuration of the waterwheel-driven generating unit  202  is similar to the configuration of FIG. 10, with the exception of the following detailed additions and modifications. 
     Firstly, the waterwheel  212  is adjustably mounted such that it rotates in a pitchback direction. Thus, the top of the waterwheel  212  moves in a direction toward the upstream side of the waterwheel  212 . Secondly, the waterwheel-driven generating unit  202  includes a deflectory plate  270  attached to the lower surface of the steel frame platform  228 . The deflectory plate  270  is a concave, curved steel plate which has a length equal to the width of the waterwheel  212 . The first edge  272  of the deflectory plate  270  is attached to the lower surface of the steel platform  228 . The second edge  274  of the deflectory plate  270  protrudes downwardly into the flow of water, just downstream of the downstream edge of the chute  214 . 
     Thirdly, the chute  214  in the pitchback embodiment is slightly modified, as compared to the chute in the overshot embodiment. In the pitchback embodiment, the downstream edge  276  of the chute  214  is curved downwardly to facilitate the transition of the water to a vertical direction. Water flowing over the adjustable chute  214  is deflected downwardly by the deflectory plate  270  such that the water flows against the waterwheel&#39;s buckets  216 , forcing the waterwheel  212  to rotate in a reverse, or pitchback direction. A steel shroud  226 , located near the lower section of the waterwheel&#39;s downward rotation, prevents water from flowing out of the buckets  216  until the buckets  216  reach a point near the lowest point of the waterwheel&#39;s rotation. 
     The pitchback embodiment of the waterwheel-driven generating unit  202  also includes one or more booster jets  244  which direct high pressure streams of water against the buckets  216  at the waterwheel&#39;s lowest point of rotation. The booster jets  244  utilize a second configuration for adjusting the position of the booster jets  244  in relation to the fixed portion of the supply conduit to maintain the elevation and direction of the jets constant in relation to the position of the bottom of the waterwheel  212 . Although shown with the pitchback embodiment, use of this booster jet nozzle configuration is not strictly limited to use with the pitchback embodiment. 
     It should be understood that the following detailed description of one booster jet  244  configuration in this embodiment is typical of all booster jets  244  in this specific embodiment. The first end  264  of the vertical nozzle  254  is hingedly attached to the lower end  256  of the conduit  246 . While FIG. 11 shows two fasteners  278 , such as threaded fasteners and nuts or rivets, attaching the first end  264  of the nozzle  254  to the lower end  256  of the conduit  246 , any suitable fastener providing hinged movement between the nozzle  254  and the conduit  246  may be used without departing from the scope of the invention. 
     A spring  280  connects the second end  266  of the vertical nozzle  254  to a point on the conduit upstream of the lower end  256  of the conduit  246 , near the lower end  256  of the conduit  246 . The spring  280  forces the second end  266  of the nozzle  254  close to the waterwheel rim  268 , such that the waterwheel rim  268  rotates close to the second end  266  of the nozzle  254  as the waterwheel  212  rotates. The nozzle  254  is positioned close to the waterwheel  212  in a position such that the nozzle  254  directs a high pressure stream of water against the waterwheel buckets  216  at a location near the lowest point of the waterwheel&#39;s rotation. 
     The high pressure water stream simultaneously applies a pressure to the waterwheel buckets  216  in the same rotational direction as the pitchback water pressure applied to the buckets  216  at the top of the waterwheel  212 . Thus, the pressure applied by the high pressure streams from the nozzle enhances the rotating pressure applied to the waterwheel  212  by the upper pitchback water pressure. This combined force results in a higher output waterwheel-driven generating unit. Additionally, in the pitchback mode, the discharge of both the upper pitchback water which acts upon the buckets  216  and the lower booster jet water stream which acts upon the buckets  216  is directed downstream. This downstream direction of water results in less build-up in the downstream water level and consequently increases the available driving force to generate power. 
     In operation, the waterwheel-driven generator unit  202  has maximum output when the waterwheel  212 , the shroud  226 , booster jets  244  and the chute  214 , as well as the other components in the system, are positioned at a proper height with respect to each other and with respect to the headwater I and the tailwater II. The waterwheel-driven generator unit  202  includes various height control cables  236 , platform  228  and winches  238  used to adjust the height of the shroud  226  and the chute  214 . The control cables  236 , platform  228  and winches  238 , as well as their most efficient levels of operation, are similar to the control cables, platform, winches and efficient levels of operation disclosed in the inventors&#39; own U.S. Pat. No. 5,440,175. 
     While the preferred embodiments have been shown and described, it will be understood that there is no intent to limit the invention by such disclosure, but rather, is intended to cover all modifications and alternate constructions falling within the spirit and scope of the invention.