Abstract:
A hydraulic power system is used in a river, ocean or any other body of water having a current. The method is useful for generating useful electric power from flowing water. The flowing water rotates a turbine and a pump that provides hydraulic power to an electric generator for a clean, renewable energy source. The hydraulic power system tethered to the bottom of a body of water and a positive buoyancy mechanism can be integrated or tethered to the pump assembly. The positive buoyancy can support the pump assembly at a predetermined distance above the sea floor.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 62/015,707, “Positive Boyancy Hydraulic Power System And Method” filed Jun. 23, 2014 which is hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    Water has long been used as a source of energy. For over a century, water has been used to generate electricity as it flows from higher to lower elevation, rotating hydraulic turbines to create electricity. Current power, although not widely used, can also generate electricity by utilizing the same principle. 
         [0003]    Transforming the energy in water into electricity is considered to be a clean, renewable source of energy, emitting no greenhouse gases when compared to fossil fuels. It has a low operating cost once installed and can be highly automated. An additional benefit is that the power is generally available on demand since the flow of water can be controlled. 
         [0004]    Using hydro power also has disadvantages. Dams can block fish passage to spawning grounds or to the ocean, although many plants now have measures in place to help reduce this impact. The diversion of water can impact stream flow, or even cause a river channel to dry out, degrading both aquatic and streamside habitats. Hydroelectric plants can have an impact on water quality by lowering the amount of dissolved oxygen in the water. In the reservoir, sediments and nutrients can be trapped and the lack of water flow can create a situation for undesirable growth and the spread of algae and aquatic weeds. 
         [0005]    While the use of water to produce electricity is an attractive alternative to fossil fuels, the technology must still overcome obstacles related to space requirements, building costs, environmental impacts, and the displacement of people. Further, possible locations for new hydropower projects are very limited. What is needed is a water powered system that can be used without the use of traditional means such as Hydroelectric plants. 
       SUMMARY OF THE INVENTION 
       [0006]    In various embodiments, a hydraulic power system and method used in a fluid such as a river or any other body of water having a current. The system can include a hydraulic power system that is tethered to a floor at the bottom of the body of water. The inventive system can include a pump assembly that is coupled to a turbine that uses fluid movement to rotate the turbine and power the pump. A positive buoyancy structure can be tethered to the pump assembly that causes the pump assembly to be positioned above the floor at the bottom of the body of water. The positive buoyancy structure can potentially rise to the surface of the water but also maintain the pump assembly and turbine at a predetermined tethered distance below the surface of the water. The positive buoyancy structure can have a shape and pitch that uses the water velocity to generate lift and help to maintain the pump assembly above the water floor. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  illustrates a side view of an embodiment of the hydraulic power system; 
           [0008]      FIGS. 2A and 2B  illustrate a side view of an embodiment of a variable buoyancy mechanism; 
           [0009]      FIG. 3  illustrates a turbine pump system, piping and on a closed loop energy generation system; 
           [0010]      FIG. 4  illustrates a turbine pump system, piping and on an open loop energy generation system; 
           [0011]      FIG. 5  illustrates an electrical generator system and on electrical energy generation system; 
           [0012]      FIGS. 6 and 7  illustrate an embodiment of a pump assembly with the turbine on the back end of the pump assembly structure. 
           [0013]      FIGS. 8 ,  9  and  10  illustrate front views of pump assemblies with buoyancy structures; 
           [0014]      FIG. 11  illustrates a top view of an embodiment of the buoyancy structure with wings; 
           [0015]      FIG. 12  illustrates a top view of an embodiment of the pump assembly with wings; 
           [0016]      FIG. 13  illustrates an embodiment of the pump assembly having an integrated positive buoyancy system without the buoyancy structure; 
           [0017]      FIG. 14  illustrates an embodiment of the pump assembly having an integrated positive buoyancy system without the buoyancy structure; 
           [0018]      FIGS. 15 ,  16  and  17  illustrate front views of the pump assemblies. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    The present invention is directed towards a hydraulic power system and method used in a fluid such as a river or any other body of water having a current. In an embodiment the inventive system can include a hydraulic power system that is tethered to a floor at the bottom of the body of water. The inventive system includes a pump assembly that is coupled to a turbine that uses fluid movement to rotate the turbine and power the pump. A positive buoyancy structure can be tethered to the pump assembly that causes the pump assembly to be positioned above the floor at the bottom of the body of water. The positive buoyancy structure can potentially rise to the surface of the water but also maintain the pump assembly and turbine at a predetermined tethered distance below the surface of the water. In addition to the upward buoyancy force, the positive buoyancy structure can have a shape and pitch that uses the water velocity to generate lift and help to maintain the pump assembly above the water floor. 
         [0020]    With reference to  FIG. 1 , a hydraulic power system  100  is illustrated that includes a pump assembly  101  with a turbine  103  coupled to a front end of the pump assembly  101 . The turbine  103  can have a plurality of blades  104  that rotate about a first shaft  105 . The first shaft  105  is coupled to a gearing system  107  that can change the rotational velocity of a second shaft  109  mounted between the gearing system  107  and a pump  111 . In the illustrated embodiment, the gearing system  107  may be placed between the turbine  103  and the pump  111 . The turbine  103  can have a rotational velocity that is proportional to the velocity of the water  113  relative to the turbine  103 . Thus, the rotational velocity of the turbine  103  and first shaft  105  can be variable. The turbine  103  can be coupled by the first shaft  105  to a gearing system  107  that can increase or decrease a rotational velocity of the second shaft  109  relative to the first shaft  105 . The rotational energy from the turbine  103  can be transmitted through the first shaft  105 , gearing system  107  and second shaft  109  to the pump  111 . 
         [0021]    The system can include a tether system with a plurality of high strength tether lines  115  coupling the pump assembly  101  to the floor  117  of the body of water  113 . A buoyancy structure  121  can be coupled with tether lines  115  to the top of the pump assembly  101  and the buoyancy structure  121  can help to lift the pump assembly  101  above the floor  117  and prevent the turbine  103  from contacting the floor  117 . The buoyancy structure  121  can also keep the pump assembly  101  below the surface  123  of the water  113  to prevent the top of the turbine  103  from coming out of the water  113 . In an embodiment, the buoyancy structure  121  includes a variable buoyancy mechanism  125 , which can alter the upward force applied to the pump assembly  101 . In calm conditions with lower velocity water, less upward force can be required to keep the pump assembly  101  at the proper vertical position within the water  113 . Thus, less buoyant forces from the buoyancy structure  121  are necessary. However, as the water  113  flow increases, the drag forces on the pump assembly  101  will also increase, which will pull the pump assembly  101  downstream. A greater buoyant force can be required to counteract the drag force and pull the pump assembly  101  back to the desired position. In an embodiment, the pump assembly  101  can have a positive buoyance and the buoyancy structure  121  can supplement these positive buoyant forces. 
         [0022]    In order to minimize the drag forces on the pump assembly  101 , the housing of the pump assembly  101  may be made to have a hydrodynamic shape with a rounded front end and a tapered back portion. By having a smooth hydrodynamic shape, the forces overcome the drag forces and raise the pump assembly  101  to the proper height within the water  113  can be minimized. Because the hydrodynamic drag does not provide any benefit to the inventive system, this drag should be minimized. 
         [0023]    With reference to  FIGS. 2A and 2B , in an embodiment, the variable buoyancy mechanism  125  can include a compressible volume  127  of gas with an actuator  129  to alter the gas volume  127 . When the volume  127  is allowed to expand as shown in  FIG. 2A , the buoyancy force will increase and when the volume  127  is compressed as shown in  FIG. 2B , the buoyancy force will decrease. In an embodiment, the compressible volume  127  can be a gas cylinder with a piston  131  that is coupled to an actuator  129 , which can be controlled to compress or decompress the gas volume  127  in the cylinder  133 . The cylinder  133  and exposed side of the piston  131  may be exposed to the ambient water pressure so that when the cylinder  133  is deep in the water, the water pressure may tend to further compress the cylinder . Thus, the actuator may need to oppose the water pressure by expanding the cylinder volume  127 . With reference to  FIG. 1 , by controlling the buoyancy, the buoyancy structure  121  can control the upward force and the vertical position of the pump assembly  101 . 
         [0024]    With reference to  FIG. 3 , a more detailed illustration of the hydraulic power system  101  is shown. The pump  111  can circulate a fluid such as water through a piping system to an onshore power station  141 . The pump  111  can be a closed loop system as shown where the liquid in the system circulates from the pump  111  through the piping system  143  to the power station  141  and then back through the piping system  143  to the pump  111 . This closed loop system can be preferable because sediment and debris can be removed from the circulating fluid (such as water), which can damage the pump  111  and/or power station  141 . In this illustration, the piping system  143  is a closed loop system with concentric outlet and return paths. The liquid can be pumped on shore to the power station  141  through the center pipe  145  and the liquid may return through the outer piping  147 . Alternatively, the liquid can be pumped on shore to the power station  141  through the outer piping  147  and the inner pipe  145  can be the liquid return. 
         [0025]    In an alternative embodiment with reference to  FIG. 4 , the system can be an open loop system where ambient water is pumped from the pump  111  through the piping system center pipe  145  to the onshore power station  141  and then released back to the body of water  113  through an outlet pipe  149 . The open loop system can be more energy efficient because there is less friction and pressure losses due to the liquid flowing through the piping system center pipe  145 . However, the water being pumped may need to be filtered through a filter  151  to prevent debris from entering the pump  111 , which can add fluid flow friction and reduce the efficiency of the system. In other embodiments the pump  111  can be used to pressurize a compressible fluid that runs in an open loop as shown in  FIG. 3  or closed loop as shown in  FIG. 3  to an on shore power system  141 . 
         [0026]    In yet other embodiments, the pumps can be replaced by other energy producing devices such as electrical power generators  181 , which can convert the rotational energy transmitted from the turbines  103  into electrical power. In this embodiment, the generator  181  can produce direct current or alternating electrical current that can be transmitted through electrical conductors  183  away from the generator assembly  191  to an on shore power station  185 . In each of these alternative embodiments, the inventive system can utilize the positive buoyancy and or hydrodynamic lift of the wings to maintain the position of the generator assembly  191  and turbine  103  above the floor  117 . 
         [0027]    With reference to  FIG. 6 , another embodiment of the pump assembly  201  is illustrated with the turbine on the back end of the pump assembly  201  structure. This configuration can provide hydrodynamic stability to the system because the drag generated by the turbine  103  is now at the rear of the assembly where there is less tendency for the drag forces to push the pump assembly  201  out of alignment with the water flow. Another benefit is that as the drag forces push the pump assembly  201  down stream, the tethers  115  will lie at a more acute angle in relation to the water floor. However these angled tethers  115  will be less like likely to interfere with the turbine  103  rotation. In an embodiment, the pump assembly  201  can have a positive buoyance and the buoyancy structure  121  can supplement these positive buoyant forces. 
         [0028]    With reference to  FIG. 7 , if the water level  123  decreases in the body of water  113 , the buoyancy structure  121  may float on the surface  123  of the water  113 , which can result in the pump assembly  201  and turbine  103  being lowered close to the sea floor  117 . When the water lever  123  rises, the pump assembly  201  will rise higher over the sea floor  117  until the tethers  115  are all tights. However, the turbine  103  will not rise above the water  113  surface level  123 . 
         [0029]      FIGS. 8 and 9  are front views of  FIG. 1  and  FIG. 5  respectively. The tethers  115  between the floor  117  and the pump assemblies  101 ,  201  can be angled outward and coupled to the outer sides of the pump assemblies  101 ,  201 . This configuration can be necessary to counter act the torque forces applied to the pump assemblies  101 ,  201  by the turbines  103 . For example, if the turbines  103  rotate clockwise facing the front of the system then the rotational force, which drives the gear system and pump, will create a clockwise torque on the pump assembly. By placing the tethers  115  as wide as possible on the pump assemblies  101 ,  201 , the tethers  115  can better resist the torque forces from the turbine  103 . The torque force can be represented by F x R which is the distance from the center shaft. Since the tethers  115  may only resist tension, the torque force may be mostly applied to the tethers  115  coupled to the left side of the pump assemblies  101 ,  201 . The torque force may also be applied to the tethers  115  extending between the pump assemblies  101 ,  201  and the buoyancy structure  121 . Again, since the tethers  115  may only function in tension, the tethers  115  on the right side of the pump assemblies  101 ,  201  may have added tension forces applied due to the torque of the turbine  103 . 
         [0030]    With reference to  FIG. 10 , another method for resisting the torque forces of the turbine  103  can be to attach extensions  161  to the sides of the pump assembly  201 . In this illustration, the extensions extend beyond the outer diameter of the turbine  103  and provide a much longer arm length R to resist the turbine torque. 
         [0031]    Thus the force F, which is an additional tension force on the tethers  115 , can be proportionally lower. In this example, the arm length R may be about 4+ times the width of the pump assembly  201 . Extensions  161  can also be placed on the buoyancy device  121  and can provide additional torque resistance. This configuration can also keep the tethers  115  away from the turbine  103  in the event that the turbine  103  moves into close proximity of the tethers  115 . 
         [0032]    With reference to  FIG. 11  a top view of an embodiment of a buoyancy structure  121  is illustrated and with reference to  FIG. 12  a top view of an embodiment of a pump assembly  201  is illustrated. In these illustrated embodiments, the extensions can be wings  163  that have elevators  165  or can be positioned to resist the turbine torque. More specifically, as the liquid flows over the wings  163 , the wings  163  can be configured to generate a rotational torque on the pump assembly  201  that resists the turbine  103  torque. For example, the left elevator  165  can be raised and the right elevator  165  can be lowered to produce a counter clockwise torque on the pump assembly  201 . Since tether  115  tension forces can be transmitted from the buoyancy structure  121 , these wings  163  can also be configured to transmit a counter clockwise torque. 
         [0033]    In another embodiment, the wings  163  can provide lift that can supplement the upward buoyant forces of the buoyancy structure  121  and/or the pump assembly  201 . The lift can be produced by the flow of liquid over the wings, which can have an upward pitch. The wing  163  lift can also be generated with the elevators  165 , which can be raised to cause the wings to generate lift and the lift force can be used to put the tethers  115  in tension. 
         [0034]    In another embodiment with reference to  FIG. 13 , the pump assembly  101  can include an integrated positive buoyancy system (as described above with reference to  FIGS. 2 and 3 ). Thus, the system may include a turbine  103  coupled to the pump assembly  101  that is tethered with tethers  115  to a floor  117  at the bottom of the body of water  113 . In this embodiment, the pump assembly  101  does not require the positive buoyancy structure. The inventive system can include a pump assembly  101  that is coupled to a turbine  103  that uses fluid movement to rotate the turbine  103  and power the pump  111  through a gear system  107 . The pump assembly  201  can have positive buoyancy that causes the pump assembly  101  to float above the floor  117  at the bottom of the body of water  113 . The tethers  115  can prevent the pump assembly  101  and turbine  103  from floating to the surface  123  of the water  113 .  FIG. 14  illustrates an embodiment of the inventive system with the turbine  103  mounted at the rear end of the pump assembly  201 . 
         [0035]      FIGS. 15 and 16  illustrate front views of  FIGS. 13 and 14  respectively. Again, the tethers  115  can be mounted to the outer side of the pump assemblies  101 ,  201  to resist the torque applied to the pump assemblies  101 ,  201  from the turbines  103 . 
         [0036]      FIG. 17  illustrates a front view of an embodiment of the inventive system with extensions  161  coupled to tethers  115  coupled to the water floor  117 . The extensions  161  can be wings  163  with elevators  165  (as shown in  FIG. 11 ) that provide a hydrodynamic counter torque force that resists the turbine  103  torque applied to the pump assembly  201  as described above. 
         [0037]    In an embodiment, force transducers  167  can be coupled to one more of the tethers  115  for monitoring the forces applied to the tethers  115 . If excessive force is applied, a warning system can notify the system operators. The forces applied to the tethers  115  can include hydrodynamic drag in the horizontal direction. In an embodiment, the hydrodynamic drag can be reduced by lowering the angle of the turbine blades  104  which can result in lowing the horizontal forces on the tethers  115 . 
         [0038]    In an embodiment, the force transducers  167  can have positive buoyancy or alternatively, buoyancy devices  168  can be coupled to the force transducers  167 . In either configuration, the force transducers  167  will not sink if the devices are accidentally dropped. This configuration can prevent the force transducers  167  from being accidentally lost. During the assembly process, the force transducers  167  can first be coupled to the tethers  115 . If the force transducers  167  are dropped, the transducer  167  and the attached tether  115  can come to rest above the sea floor  117  so that it can be easily retrieved. In contrast, if the force transducer  167  has negative buoyancy or is not coupled to a buoyancy device  168 , the force transducer  167  and any connected tether  115  will sink to the sea floor  117  when dropped. It can be difficult to see and retrieve these components if they are resting on the sea floor  117 . 
         [0039]    While one or more implementations have been described by way of example and in terms of the specific embodiments, it is to be understood that one or more implementations are not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements as would be apparent to those skilled in the art. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.