Patent Document

BACKGROUND  
       [0001]     Hydroelectric power is an efficient, abundant power source, relied upon in many parts of the world. This has led to the development of reliable turbine generators.  
         [0002]     However, in many instances constructing additional dams to store the water necessary to power these hydroelectric generators is not practical due to the nature of the water source. For example, the grade of the available terrain may be too shallow to allow a dam of sufficient height to develop the required motive flow for the efficient operation of a hydroelectric turbine. In other situations, there may not be a stream or river to dam. In addition, the ecological impact or economic expense of constructing such a dam may be prohibitive.  
         [0003]     In yet a further situation, dammed water may be desired to be transferred to a distant or elevated location. However, the number of electrical pumps needed may consume a considerable amount of energy.  
         [0004]     In yet another situation, an existing dam and hydroelectric generator system are available; however, an augmented system is desired for instances during extended droughts or to more fully utilize the power generation capability of the generators.  
         [0005]     What is needed is a system that consistently provides stable electrical energy in quantities suitable for addition to the electrical power grid by taking advantage of hydroelectric power generation technology. Furthermore, this system should not require a large dam to create sufficient water pressure for efficient operation of a hydroelectric generator. Alternatively, the water pressure could be used to elevate or transfer water across a distance. Moreover, such a system should be operable in situations where water is a scarce commodity by being capable of implementation as a closed system. Also, the system should be as efficient as possible in converting motive power into electricity.  
       SUMMARY  
       [0006]     The invention, generally referred to as a hydro engine or variable buoyancy float engine, meets these and other needs. The invention relates to hydroelectric generators, and has special application to a generator which is activated by a fluid flowing through a conduit. By concentrating the weight of a float tank onto a small area, a pressurized stream of fluid is provided making full use of the generator. Recycling the float tank for its next stroke is performed efficiently with a minimum of mechanical parts. In addition, the system is ecologically sound.  
         [0007]     In its closed system form, one version consistent with the invention uses a float tank that can become negatively buoyant by allowing its inner chamber to flood or to become positively buoyant by draining its ballast. The descent of the float tank pushes a piston into a shaft to force fluid through a hydroelectric generator. Fluid discharging from the generator is captured in a recycling pool which in turn refills the shaft. The float tank is drained into a drain tank which in turn allows the float tank to ascend. The drain tank is recycled by first allowing it to descend over a plug, thus expelling its fluid back into the fluid chamber. The slidable plug then descends through the drain tank, drawing air back into the tank, whereby the drain tank and plug are enabled to ascend together. A plurality of valves control the flow of air and water in the system.  
         [0008]     Additional features of the hydro engine include controlling the flow into the turbine intake and out of the recycling pool so that the float tank can be held in position during draining or filling with ballast.  
         [0009]     In its open system form, a version consistent with the invention includes the aforementioned apparatus; however, the discharge from the generator may not be captured and the shaft may be refilled instead by another fluid source. Alternative uses for the open-system version include utilizing the shaft water pressure to elevate water or to transfer water across a distance.  
         [0010]     The above and other objects and advantages of the present invention shall be made apparent from the accompanying drawings and the description thereof.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  is a cross-section view of a variable buoyancy float engine according to the principles of the present invention.  
         [0012]      FIG. 2  is a partial cross-section view of the drain tank and plug shown in  FIG. 1 .  
         [0013]      FIG. 3  is a partial cross-section view, similar to  FIG. 2 , of the drain tank and plug after the drain tank has received the drained fluid from the float tank.  
         [0014]      FIG. 4  is a partial cross-section view, similar to  FIGS. 2 and 3 , of the drain tank and plug after the drain tank has descended.  
         [0015]      FIG. 5  is a partial cross-section view, similar to  FIG. 2-4 , of the drain tank and plug after the plug has descended. 
     
    
       [0016]     The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the invention.  
       DETAILED DESCRIPTION  
       [0017]     Referring to the figures and to  FIG. 1  in particular, a variable buoyancy float engine or system for generating work  10  is shown. The system  10  includes a fluid chamber  12  that is filled with a stored fluid  14  such as water. The fluid chamber  12  has an upper reservoir  16  and a lower reservoir  18 . The reservoirs  16 ,  18  are connected by a channel  20  which permits free flow of the fluid  14  between the two reservoirs  16 ,  18 . While two distinct reservoirs  16 ,  18  are illustrated, in alternative embodiments, the fluid chamber  12  may be comprised of a single reservoir or a plurality of reservoirs.  
         [0018]     Contained within the upper reservoir  16  is a float tank  22 . The float tank  22  has an inner chamber  24  that can hold a fluid ballast  14  such as water. The float tank  22  has a water vent or drain valve  26  through which the fluid  14  can be let in as trapped air is released through an upper hatch or air vent valve  28 . The air vent valve  28  is connected to a source of air, like the atmosphere, through a pipe  30  or other like conduit.  
         [0019]     The system  10  also contains a drain tank  32  which is positioned in the lower reservoir  18  of the fluid chamber  12  so as to allow fluid  14  from the float tank  22  to gravitationally flow into the drain tank  32 . A float tank drain receiver valve  34  attached to the drain tank  32  operationally connects with the float tank drain valve  26 . As shown in  FIG. 2 , a retractable pipe  36  and an elbow pipe  38  can be used between the two valves  26 ,  34  to facilitate fluid  14  communication from the float tank  22  and the drain tank  32 . The retractable pipe  36  could be an accordion pipe, a telescopic pipe, or any like pipe which allows for longitudinal expansion and retraction. However, in alternative embodiments the float tank  22  and the drain tank could be positioned so as to allow the two tanks  22 ,  32  to be directly coupled to each other, without the need for any retractable pipes. In addition, the movement of the float tank  22  and/or the drain tank  32  could be used to facilitate the mating and the operation of the valves  26 ,  34 .  
         [0020]     The drain tank  32  also contains an air vent valve  40 . The air vent valve  40  is connected to a source of air, such as the atmosphere, via a pipe  42  or other like conduit. The air pipe  42  has an upper valve  44  and a lower valve  46 . Here retractable pipes  48 ,  50  and an elbow pipe  52  can be used to facilitate the connection between the air vent valve  40  and the respective air pipe valves  44 ,  46 . The retractable pipes  48 ,  50  could be accordion pipes, telescopic pipes, or any like pipes which allow for longitudinal expansion and retraction. However, in alternative embodiments the air vent valve  40  and the respective air pipe valves  44 ,  46  could be positioned so as to allow direct coupling, without the use of retractable pipes. In addition, the vertical movement of the drain tank  32  could be used to facilitate the mating and operation of the valves  40 ,  44 ,  46 .  
         [0021]     As shown, the drain tank  32  has a pair of drain tank equalizing valves  54 ,  56  which allow fluid to flow from the drain tank  32  into the lower reservoir  18 . While two valves  54 ,  56  are shown, in alternative embodiments, any number may be used. Additionally, in alternative embodiments the float tank drain receiver valve  34  and/or the air vent valve  40  could function as equalizing valves.  
         [0022]     A plug  58  is slidably connected within the drain tank  32 . In operation, the drain tank  32  descends over the plug  58  and the plug  58  can descend below the floor or base  60  of the lower reservoir  18 . The drain tank  32  has a seal ring (not shown) which prevents fluid from flowing between the drain tank  32  and the lower reservoir  18  at the area where the plug  58  contacts the drain tank  32 . Similarly, the base  60  of the lower reservoir  18  also contains a seal ring (not shown) which prevent fluid  14  from escaping from the lower reservoir  18 . The base or bottom  62  of the plug  58  is supported by at least one (two shown) mechanical plug stops  64 .  
         [0023]     One embodiment of the present invention includes a float tank guide  66  which constrains the float tank  22  to translate vertically in the upper reservoir  16 . As shown, the float tank guide  66  is comprised of a pair of generally vertical guide posts  68 , to which the float tank  22  slidably contacts or is connected, a float tank upper stop  70 , and a float tank lower stop  72 .  
         [0024]     A discharge piston  74  is connected to the bottom  76  of the float tank  22 . The opposite end of the piston  74  terminates in a discharge piston seal  78 . The piston  74  fits and vertically translates within a discharge shaft  80 . A piston ring access room  82  is provided to aid in maintaining the discharge piston ring  78  that would be expected to wear during operation.  
         [0025]     In one embodiment, the piston  74  can be connected directly to a converter such as gear assembly, a pump like mechanical system (not shown) which is adapted to convert mechanical energy into work. Alternatively, the converter could be directly and operatively connected to the float tank  22 .  
         [0026]     As shown, the lower portion  84  of the shaft  80  contains a second fluid  86  such as water. While the first fluid  14  and the second fluid  86  may be the same, and will typically be water, the two bodies of fluid  14 ,  86  will typically not mix. In some embodiments, however, it may be advantageous to use fluids in the two fluid bodies  14 ,  86  with different buoyancy, viscosity, or corrosive properties.  
         [0027]     A shown, the shaft  80  is connected to a convertor  88  in the form of a hydroelectric generator which has a turbine intake (not shown) and a turbine discharge (not shown). Any suitable generator, including induction type generators like a Pelton turbine, may be used. As shown, a generator valve  90  is interposed between the lower portion  84  of the shaft  80  and the generator  88 . The generator valve  90  may be in the form of a vein valve. The second fluid  86  is forced through the generator  88  by the piston  74  and passes out of the turbine discharge and into a discharge or recycling pool  92 .  
         [0028]     The recycling pool  92  is typically positioned substantially lower than the upper reservoir  12  so that the base or bottom  94  of the recycling pool  92  and the feedback line  96  is vertically positioned at an elevation to permit an equal amount of the fluid  86  that was discharged into the recycling pool  92  from the generator  88  to be recycled back into the shaft  80 . A recycling pool valve  98  is interposed between the recycling pool  92  and the shaft  80  and is adapted regulate the flow of the fluid  86  from the recycling pool  92  back into the shaft  80 . The recycling pool valve  98  may be in the form of a vein valve. In alternative embodiments, the feedback line  96  could be shortened or even eliminated, allowing for the recycling pool valve  98  to directly connect the recycling pool  92  with the shaft  80 .  
         [0029]     The generator valve  90  and the recycling pool valve  98  can further-be used to regulate the vertical motion of the float tank  22 . For example the generator valve  90  and the recycling pool valve  98  can be closed to prevent air or fluid from exiting the shaft  80 . This will keep the float tank  22  from beginning to descend before it is filled with fluid  14 . Thus, when the generator valve  90  is opened and the float tank  22  begins to descend, the filled float tank  22  will exert a sufficient pressure on the piston  74  for efficient operation of the hydroelectric generator  88 . Similarly, when the float tank  22  is at its lower position, the generator valve  90  and the recycling pool valve  98  can again remain closed to keep the float tank  22  at its lower position until the fluid  14  is drained into the drain tank  32 . At that point, the recycling pool valve  98  can be opened, allowing the now buoyant float tank  22  to ascend.  
         [0030]     In operation, the system  10  begins with the upper reservoir  16  being filled with fluid  14 , and the inner chamber of the float tank  22  and the drain tank  32  substantially empty of fluid  14 . The float tank  22  is thus positively buoyant and positioned at or near its upper limit near the top of the upper reservoir  16 . The trapped air in the inner chamber  24  offsets the weight of the empty float tank  22 .  
         [0031]     The water vent  26  is opened to allow fluid  14  to be taken into the inner chamber  24  of the float tank  22  as air trapped within the inner chamber  24  is released through the upper air hatch  28 . Once the float tank  22  is filled with fluid  14 , the generator valve  90  is opened and the now negatively buoyant float tank  22  is allowed to descend. In some embodiments, other mechanical stops or braces may also need to be released to allow the float tank  22  to begin its descent. As the negatively buoyant float tank  22  descends, its weight is transferred through the discharge piston  74  into pressurizing the fluid in the shaft  80 . The discharge piston seal  78  prevents this pressurized fluid in the shaft  80  from bypassing back into the upper reservoir  16 . The pressurized fluid  86 , unable to go directly into the recycling pool  92  because the recycling pool valve  98  is closed, goes through the generator valve  90  and into the turbine intake of the hydroelectric generator  88 .  
         [0032]     Once the float tank  22  reaches its lower limit in the upper reservoir  16 , the generator valve  90  is closed to keep the float tank  22  at its lower position while it drains it fluid  14  into the drain tank  32 . As shown in  FIG. 3 , a pipe  36  is extended to connect the float tank drain valve  26  ( FIG. 1 ) with the float tank drain receiver valve  34  which is connected to the drain tank  32 . Alternatively, the two valves  26 ,  34  could be directly coupled. The air vent  28  in the float tank  22  is also connected and opened to an air supply pipe  30  which permits the fluid  14  in the float tank  22  to gravitationally flow into the drain tank  32 . After the float tank  22  has drained, the float tank drain valve  26  is closed and the recycling pool valve  98  is opened, allowing the float tank  22  to ascend.  
         [0033]     While the float tank  22  is ascending, as shown in  FIG. 4 , the drain tank equalizing valves  54 ,  56  are opened and the mechanical stops  100  are disengaged from the drain tank support member  102  allowing the drain tank  32  to gravitationally descend over the plug  58 . The drain tank  32  will descend to a point at or near the top  104  of the plug  58  and may in alternative embodiments be supported by the plug  58 , by the bottom  60  of the lower reservoir  18 , or by another mechanical stop (not shown).  
         [0034]     Next, as shown in  FIG. 5 , the drain tank air valve  40  is connected and opened to the air supply pipe  42  via the lower air supply valve  46 . Once the air connection is established, the mechanical plug stops  64  holding the plug  58  are released and the plug  58  is allowed to gravitationally descend. The plug  58  will descend to a point where its top  104  is at or near the bottom  106  of the drain tank  32 . As the plug  58  descends, air is drawn into the drain tank  32  and it becomes buoyant. The drain tank  32  may be kept in place by means of other mechanical stops (not shown) until it is filled with air. The air valve  40  is then closed and the drain tank  32  along with the plug  58  buoyantly ascend back to their starting positions. A set of upper mechanical stops  108  may be used to position the drain tank  32  in its proper position.  
         [0035]     This closed system  10  lends itself to a number of variations. For example, an upper reservoir vent cap (not shown) and recycling pool vent cap (not shown) could be use to maintain atmospheric pressure within each containment chamber while also providing protection from the elements. In addition, the upper reservoir  12  could be filled from an available water supply at a higher elevation, thus allowing gravity feed with the corresponding energy savings. Also, the float tank  22  could be structurally held during draining or filling rather than relying on the pressure of suction in the shaft  80 . Moreover, some applications could omit the holding of the float tank  22  at its upper or lower limit during transitions. Also, more than one float tank  22  may be able to feed a single generator  88  and discharge into a single drain tank  32 , allowing for a nearly constant motive fluid flow to be provided to the hydroelectric generator  88 , thus allowing for continuous generation of power.  
         [0036]     Another embodiment of the present invention provides for a float actuated hydroelectric generator open system. In one implementation, there is not a need for a drain tank  32  but rather the float tank  22  can be drained directly to a destination outside of the fluid chamber  12 . A fluid source (not shown) refills the upper reservoir  16 . The operation of the float tank  22  with its discharge piston  74  and piston seal  78  within the shaft  80  is as described above.  
         [0037]     Similarly, another embodiment of the present invention provides for a separate fluid replenishment source for refilling the shaft  80 . The fluid replenishment source could be closed during descent of the float tank  22  by an interposed replenishment valve (not shown). In yet another variation, the fluid replenishment source could also be a source for refilling the upper reservoir  16 .  
         [0038]     Another embodiment consistent with the principles of the present invention would be to use the hydro engine system  10  as a large volume water pump to transfer water through an aqueduct for irrigation. In this application, instead of a generator, a one-way valve allowing the hydro engine to pulse streams of water is used.  
         [0039]     The advantage of these versions and other versions consistent with the invention is that during descent of the float tank  22 , the motive force of fluid  86  passing through the hydroelectric generator  88  can be increased, allowing efficient operation. Also, the storing of fluid, such as water, in an upper reservoir minimizes the need for ecologically unsound dams.  
         [0040]     Although ground water is assumed to be the most plentiful and practical fluid for practicing the hydro engine invention, obviously many other fluids could be substituted. For example, operation of the hydro engine in sub-freezing temperatures may require mixtures that would remain liquid. Corrosion of materials may be of consideration. In addition, versions consistent with this invention could utilize manufacturing effluents, consumer waste water, or nuclear power plant cooling water, etc.  
         [0041]     The hydro engine lends itself to augmenting an existing hydroelectric facility. Given constraints on the amount of water that can be drained from behind the hydroelectric dam, the hydro engine could fulfill a way of continuing to provide pressurized water to the generators.  
         [0042]     While the present invention has been illustrated by a description of various embodiments and while these embodiments have been described in considerable detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method, and illustrative example shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant&#39;s general inventive concept.

Technology Category: 2