TECHNICAL FIELD
The technical field relates to systems and methods for the conversion of mechanical energy into fluid power.
BACKGROUND
Current systems and methods for converting mechanical energy into fluid power generally rely on pistons moving within cylinders, centrifugal rotors and/or gear rotors. These systems require large precision machined surfaces, complex hydraulics, numerous parts and components, and very tight tolerances to prevent hydraulic or fluid leakage. These systems are suited for compact power units and/or high volume fluid flow at high pressures, there is a need for a low-cost, robust technology for converting regular periodic mechanical motion, such as that produced by ocean waves or slow moving machinery, into a flow of fluid power.
SUMMARY
An embodiment of a system for converting mechanical energy into fluid power includes a fluid and one or more fluid inflatable containers which are arranged to receive mechanical energy from a plunger mounted on a shaft, such that the flexible wall of the fluid inflatable container forms a rolling lobe in response to changes in volume, enclosed within a cylindrical enclosure or drum, said shaft running axially through the center of the drum and coupled to the drum by bearings so that the drum and shaft may move freely in relation to one another, one or more vanes running longitudinally down the length of the drum and extending radially from their attachment point at the inner surface of the drum to the surface of the shaft. The source of mechanical energy may be connected directly or indirectly to either the shaft or to the drum. The fluid inflatable containers are arranged in a whole or partial annular ring inside of the drum around the shaft so that each container exerts expansive force between a vane fixed to the drum and the one or more plungers fixed to the shaft. A volume of the fluid is placed in the one or more fluid inflatable containers. Mechanical force or motion applied to the system causes the plunger to press into the fluid inflatable container, forming a rolling lobe that eliminates most of the friction between the fluid inflatable container and the inner surface of the drum, and expels fluid creating fluid flow, which can be directed to an energy conversion system or other purpose. The system may include valves to produce a uni-directional flow of fluid produced in response to mechanical motion in the system, and accumulators, pressure vessels, and/or other fluid power storage devices may be used to smooth out the flow of power output from the system. In an embodiment an arced or curved plunger is used to assist in creating the rolling lobe. The plunger and rolling lobe system may be configured to operate in non-linear or semi-circular rotation upon application of mechanical force to either the shaft or the drum.
The system may incorporate use of one or more elastic tensioning devices to bias the system in a specific position, to return the system to starting position after each stroke or cycle, or to tune the resonant frequency of the system to better suit the operating conditions. In one embodiment, a computer with a processor and memory is used to monitor and control the system. The system may be deployed at sea to generate electricity.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a cutaway view of an embodiment of a system for converting mechanical energy to fluid power in the top dead center position with main component parts in position.
FIG. 2 shows a view of an embodiment of a system for converting mechanical energy to fluid power with an arced actuator rotated to approximately 90° counter-clockwise position without the rolling lobe sections shown.
FIG. 3A shows a cutaway view of an embodiment of a system for converting mechanical energy to fluid power with a movable member transferring external force to the shaft to move an arced actuator in a repeatable arced motion.
FIG. 3B shows a partial cutaway view of an embodiment of a system for converting mechanical energy to fluid power showing the rotation of the plunger inside the boot and without the rolling lobe sections shown, as well as exemplary additional components for converting the flow of fluid power to electricity.
FIG. 4 shows a close-up partial cutaway view of an embodiment of a system for converting mechanical energy to fluid power using limited arcuate motion and fluid inflatable containers.
FIG. 5 shows three versions of the many possible configurations of plungers that force the fluid inflatable container to form a rolling lobe as they travel through an arcuate path inside the drum
FIG. 6 shows an example of one of the lower sections of a fluid inflatable container.
FIG. 7 shows an example of the upper section of a fluid inflatable container to form a rolling lobe.
FIG. 8 shows a close-up partial cutaway view of an embodiment of a system for converting mechanical energy to fluid power, showing one plunger pressing into a fluid inflatable container.
FIGS. 9A, 9B, and 9C show the use of one or more elastic tensioning devices to bias the system in a specific position, to return the system to starting position after each stroke or cycle, or to tune the resonant frequency of the system to better suit the operating conditions.
FIGS. 10A and 10B show a system of bearings that hold the shaft in an embodiment of a system for converting mechanical energy to fluid power.
FIG. 11A shows a prior art system for converting the energy of reciprocating ocean wave energy into fluid power.
FIG. 11B shows an embodiment of the system deployed in a wave or tidal current energy producing device such as a reciprocating linear motion attenuator.
FIG. 12 shows the system deployed in a wave or tidal energy producing device such as a wave flap.
FIG. 13A, the prior art portion of a sea surface system of tethered buoys used for converting the motion of surface ocean waves into fluid power is shown.
FIG. 13B, shows an embodiment of the system mounted at the junction of a chain of linked, tethered buoys, which float in the waves on the surface of the ocean.
FIG. 13C shows a more detailed depiction of the location of the system at the linkages of a series of tethered buoys positioned to capture mechanical energy from the buoys' reciprocating vertical and horizontal motion relative to one another
FIG. 14 shows the fluid circuit from the rolling lobe and plunger system to a hydraulic motor and generator to produce electricity under computer control.
FIG. 15 shows a manifold and check valve schematic that enables reciprocating mechanical force to direct fluid through the turbine generator in one direction rather than require a bi-directional turbine generator.
FIG. 16 shows the use of an accumulator device in the circuit to smooth the fluid flow.
DETAILED DESCRIPTION
An enduring challenge is posed by the high cost and fragility of machines used to convert mechanical motion produced by natural systems, such as ocean waves, into useful power. Many such devices rely on conversion of the reciprocating motion of waves into mechanical rotary power or into fluid power by use of pistons such as wave attenuator devices described in U.S. Pat. No. 4,672,222 or wave flap systems as described in PCT Publication Number WO/2006/100436 published Sep. 28, 2006 for International Application Number GB2006/000906. Such systems are not well suited to the harsh environments where they are deployed such as the ocean or tidewaters, where machined parts, piston shafts, piston seals, gears, motors and pumps may be damaged by water, salt, sand, organic material and other hazards. Additionally if such systems are complicated and prone to breakdown they will be much less manageable when situated in the ocean surface or in breaking waves. There is thus a need for a robust, simple alternative to traditional hydraulic pistons or gears for converting reciprocating motion collected from mechanical sources such as machinery and ocean waves into usable fluid power.
Existing examples of wave and ocean power generating systems using traditional pistons or gear systems include the Oyster wave flap system from Aquamarine Power Ltd., Elder House, 24 Elder Street Edinburgh EH1 3DX, Scotland, UK, described in PCT Application Number GB2006/000906, the WaveRoller from AW Energy Ltd. AW-Energy Oy, Kolamiilunkuja 6, FI-01730 Vantaa Finland, described in the PCT Publication Number WO/2007/125156 and the Pelamis “Sea Snake” type surface wave attenuator system from Pelamis Wave Power, Ltd., 31 Bath Rd, Leith, Edinburgh, EH6 7AH, Scotland, UK and described in PCT Publication Number WO/2004/088129, published on Oct. 14, 2004 for International Patent Application Number PCT/GB2004/001443.
The applicant previously described a non-linear actuator system which can be used to produce a large amount of precisely controlled mechanical force without the expense of numerous precision machined components and surfaces, in International Patent Application PCT/US2010/000220 entitled “Non-Linear Actuator System and Method” filed Jan. 27, 2010 which is incorporated by reference as if fully set forth herein. The non-linear system and variations of the non-linear system described can be also used to produce fluid power from reciprocating arcuate mechanical motion. For example, the same or similar arrangement of fluid inflatable containers can be used in reverse to produce a pump that converts mechanical work into fluid power. By applying a mechanical force to either the shaft or the drum, fluid inflatable containers are compressed and fluid power is produced. The fluid power can be used for many useful purposes, for example to power a common hydraulic motor turning a generator and thus producing electrical current. The addition of a valve manifold as described herein and common in prior art makes the fluid flow uni-directional for ease of application in various fluid power systems. The resulting fluid power can be stored in accumulators, and used for many purposes including, but not limited to, the driving of hydraulic motors for the generation of electricity and the pressurization of reverse osmosis desalination systems.
Referring to FIG. 1, an embodiment of a system 100 for converting mechanical energy to fluid power includes a shaft 116 to which is fixed a vane 120, which is operatively coupled to and runs longitudinally through the center of a drum 104. Bearings (not shown) hold the shaft 116 in a central axial position within the drum 104. Reciprocating mechanical power may be applied or transferred to either the drum 104 or the shaft 116. The plungers 124′,124″ or pistons 124′,124″ are mounted to each side of the vane 120, and may be fixed with bolts or other fasteners.
A fluid inflatable container 140′,140″ consisting of a rigid section or “boot” 136′,136″ and a flexible section or “sleeve” 112′,112″ is arranged so that it is in contact with the end of the plunger 124′,124″ opposite the vane 120. Fluid is introduced through the fill ports (not shown), which may be located in the boot 136.
The sleeve 112 portion inflates and moves into the clearance between the surface of the vane 120 and the drum 104 by rolling along the surface of the vane 120. Reciprocating mechanical motion causes the shaft 116 to rotate in the drum 104 and the shaft exerts a force on the plunger 124′,124″ and forces the plunger 124′,124″ against the sleeve 112 causing hydraulic pressure to build in the fluid inflatable container and forcing fluid through the fluid power manifold (not shown) from which fluid is returned to the opposite fluid inflatable container. As one fluid inflatable container 140′,140″ is compressed and deflated, the plunger 124′,124″ moves towards or into the opposite container and is forced into the boot 136′,136″, forcing the sleeve 112 to invert upon itself and form a rolling lobe as the sleeve 112 is rolled off the drum 104 wall. As the mechanical force reciprocates, the fluid is forced back through the system. In this embodiment, the boots 136′,136″ are bolted to the drum 104.
In an alternate embodiment, the boots 136′,136″ may be bolted to each other or fitted into the drum 104 without being bolted to each other or the drum 104. Alternatively, the vane 148 may be formed by two surfaces of the boots 136′,136″ in contact with each other when the boots 136′,136″ are made of a rigid or semi-rigid material. In this embodiment, the system 100 is shown positioned at the top dead center position 144. The rolling lobe sleeve 112 is not required to slide along the wall of the drum 104, and this allows the system 100 to operate with little or almost no internal friction. The fluid inflatable containers 140 may be entirely formed from the same material as the flexible sleeve portion. The containers 140 may also have other features formed into them such as mechanical attachment features to connect the containers to the plungers and/or the fixed vane 148.
The arcuate motion of the system 100 can be extreme because the fluid inflatable container 140′,140″ does not need to resist the large stresses that would build up in an unconstrained fluid inflated container. The plunger 124′,124″ is guided in an arcuate path by the rotation of the shaft 116, so that little or no internal friction will be generated within the fluid inflatable container 140′,140″.
Referring now to FIG. 2, shown is an embodiment of system 100 for producing fluid power from reciprocating mechanical motion. The source of mechanical power (not shown) may be rotated through at least a 180° range of motion as the rolling lobe sleeves 112 (not shown) move from almost fully extended on one side, to almost fully retracted on the other side. Various embodiments of system 100 can be rotated through at least a 180° range of motion. The rigid portion or boot 136′,136″ can be made smaller to accommodate ranges of motion of greater than 180°, such as 270° or more. In an embodiment, the rigid portion or boot is not required, and the entire fluid inflatable container is made into a bladder of the same material with the same properties throughout. Low friction coatings or materials, or lubricants may be used to reduce the friction of the shaft 116 against the boot sections 136 of the fluid inflatable containers 140.
Referring now to FIG. 3A, shown is a cutaway view of an embodiment of a system 100 for converting mechanical energy to fluid power. An external force 900 applied upon a movable member 840 is transferred to either the shaft 116 or the drum 104 (depending on which is connected to the movable member 840) and is thereby made to move the arced actuator 200 in a repeatable arced motion. In the embodiment shown in FIG. 3A, a movable member 840 is operably connected to the shaft 116. A system of plungers 200 are shown in this embodiment. The plunger 200 is shown attached to the shaft 116 along a longitudinal axis. Referring now to FIG. 3B, shown is an embodiment of a system 100 for converting reciprocating mechanical motion into electricity. The action of external force 900 applied to the movable member 840 is transferred to the shaft 116 causing rotation of the plungers 200 thereby compressing the fluid inflatable containers (not shown) thus forcing fluid through a hydraulic manifold system 250 which directs the fluid power for example to a turbine generator 270 so as to produce electric current. The turbine can be bi-directional to convert the reciprocating fluid flow into rotary energy, or uni-directional when a series of check valves 255 are used to direct fluid power to the turbine in a single direction, as the mechanical force 900 reciprocates back and forth. An accumulator 260 may also be incorporated to allow storage of fluid power and to smooth the flow of fluid through the turbine 270.
Referring now to FIG. 4 a fluid inflatable container 140′,140″ is shown within the housing 104 wherein the first plunger 124′ is engaged by the first fluid inflatable container 140′. The second fluid inflatable container 140′,140″ is shown constrained by the housing wherein the second plunger 124″ is engaged by the second fluid inflatable container 140″. In this embodiment the two plungers 124′,124″ are shaped to allow a plunger 124′,124″ to slide fully into the boot 136′,136″ section of a fluid inflatable containers 140′,140″ without striking the walls and without damaging the fluid inflatable containers' 140′,140″ and without compressing the boot 136′,136″ sections.
Referring now to FIG. 5, shown are examples of various possible shapes of a plunger 124. These plungers 124a-124c are shown curving to the left. Plungers 124a-124c may similarly curve to the right. The plungers 124a-124c are shaped to provide a space between the wall of the drum 104 (not shown) and the side wall of the plungers 124a-124c sufficient to allow a rolling lobe (not shown) to form in the membrane of the fluid inflatable containers (not shown). The plunger 124a is shown with a curved, hollow shell that may be filled with a high density material such as concrete, foamed concrete, or another semi-plastic material. The material used to fill the plunger 124a may be selected based on its effect on the buoyancy of the overall system. Plunger 124b is an alternative solid, plunger shape where one of the surfaces is straight 150 and one of the sides is curved 152. Plunger 124c is shown as a solid plunger with two arced sides 154,156. The bottom surfaces of the plungers 124a-124c come in contact with the fluid inflatable containers 140′,140″. The length of a plunger 124 helps determine the plungers 124′,124″ range of motion.
In an embodiment, the rolling lobe sleeve 112 may be coupled to a bottom surface of a plunger 124′,124″. A plungers 124′,124″ may be constructed of steel, aluminum, plastic, or any other sufficiently strong rigid or semi-rigid material. It may include reinforcing ribs within to counter the forces imposed by the mechanical energy or the pressure transmitted by the fluid inflatable container 140′,140″. The plunger 124′,124″ is slightly tapered to allow the plunger 124′,124″ to smoothly displace and move the walls of the fluid inflatable container 140′,140″. The plunger 124′,124″ may include a smooth outside wall and radiused corners to avoid damage to the fluid inflatable container 140′,140″. In one embodiment, the plunger 124′,124″ is be sized so that the gap between the drum 104 wall and the plunger 124′,124″ does not exceed the maximum unsupported radius of the material making up the fluid inflatable container 140′,140″ at the system's working pressure.
Referring now to FIG. 6, in one embodiment the fluid inflatable containers 140′,140″ are made up of a lower section or boot 136 which may be a rigidly molded plastic, elastomer, or metal. This section may be continuously molded with the sleeve 112 or flexible section that forms the rolling lobe. Alternatively, it may be formed like a tire with a bead that may be swaged or otherwise coupled to the sleeve 112. The boot 136 section need only be rigid enough in operation to resist deformation and ensure that the rolling lobe sleeve 112 is the only portion of the fluid inflatable container 140′,140″ that substantially deforms in response to changes in fluid pressure and volume. In many applications, the fluid containers' 140′, 140″ internal pressure will be sufficient to eliminate the need for a distinct boot section 136. The boot 136 may incorporate a metal plate to connect it to the vane 120 in the drum 104. The boot 136 is operatively coupled to the rolling lobe sleeve 112. The boot 136 typically fills a quadrant of the drum 104, for example the lower left or right quadrant.
Referring now to FIG. 7, in one embodiment the fluid inflatable containers 140′,140″ are also comprised of a rolling lobe sleeve 112 which may be smaller than the volume that it will expand to fill as it is pressurized. The lobe sleeve 112 is coupled to the boot 136′,136″ on one end and the plunger 124′,124″ at the other. In one embodiment, the lobe sleeve 112 is connected to the bottom of the plunger 124′, 124″. Once all the components are coupled, the fluid inflatable container 140′,140″ is complete. This embodiment thus provides fluid communication between the boot 136′,136″, the sleeve 112 and the plunger 124′,124″.
Referring now to FIG. 8, in one embodiment the fluid inflatable containers 140 are simple cells that consist only of a flexible membrane such as a heat sealed, urethane coated nylon fabric with a single fill port. The fluid inflatable container 140 can also be made out of elastomers, coated fabrics, multi-ply composites, or any material that can contain the fluid flexibly. In one embodiment, the fluid inflatable container 140 is shaped to fill slightly more than one half of the drum 104 at full inflation. The fluid inflatable containers 140 may have features that allow for mechanical attachment of the top face of the fluid inflatable container 140 to the bottom of the plunger 124 such as Velcro pads, grommets, or metal loops for straps. Mechanical attachments provide greater certainty that the fluid inflatable container 140 will remain in the proper position in the enclosure. The motion of the plunger 124 combined with the internal pressure of the fluid inflatable container 140 forces the wall of the fluid inflatable container 140 to form a rolling lobe against the wall of the drum 104 as the plunger 124 travels its arcuate path.
The system 100 can operate in a very wide range of pressures. For example, in some applications the system may operate at a relatively low pressure of 150 psi, in other applications as at much higher pressures in the range of 1500 psi -1700 psi. Typically, the determining factor as to the operating pressure is the ability of the fluid inflatable containers 140 to withstand the internal pressure generated by mechanical compression of the containers by the plunger 124 over the unsupported radius of the fluid inflatable container at the rolling lobe. For example, where the plunger is a maximum of 3 inches away from the inner wall of the drum 104, and the walls of the fluid inflatable container are 0.25 inches thick, the maximum unsupported radius is about 2.5 inches. Under these conditions, the fluid inflatable containers 140 would need a wall tensile rating in pounds per square inch at least 2.5 times greater than the pressure in pounds per square inch generated by the mechanical compression of the plungers 124. One skilled in the art will appreciate that a safety factor over and above the tensile limit will generally be specified, and that particular reinforcement may be required around the port leading into the fluid inflatable containers 140.
In some embodiments, the fluid pressure is used to return the system 100 to an equilibrium state or neutral location for the vane 120 and shaft 116. In some embodiments, the neutral position places the vane 120 in the middle or center of the system 100. In another embodiment, regulation of fluid pressure and flow within the system can also help to regulate the speed of mechanical equipment. In yet other embodiments, high fluid pressure allows the system 100 to resist movement when the system 100 is not in use.
The plunger 124′,124″ may constructed by any of a number of typical industrial processes such as injection molding, drawing, assembly of cut parts into a weldment, or by casting and machining. The plunger 124′,124″ may have smooth sides, and a tapered shape in the wall from the vane 120 to the bottom. In some applications it may be useful to create very heavy plungers 124′,124″ that can serve as counterweights to the mechanical energy source, plungers 124′,124″ may also be filled with high-density materials such as liquids, concrete, composites or ceramics to add to the counterweight effect. The materials used to fill the plungers 124′, 124″ can also be used to control the buoyancy of the entire system (not shown). Plungers 124′,124″ filled with concrete are cost efficient to produce as the shell of the plungers 124′,124″ may be made of cheaper, light-weight materials which travel easier. The lightweight shells are then filled with concrete or other high-density materials. The filling process can occur on-site to reduce transportation costs. In an embodiment, plungers 124′,124″ have internal structures such as framing or ribs for stability or strength.
Tolerances on the plunger 124′,124″ can be large, on the order of ¼″ or more, as the plunger 124′,124″ is a non-precision component. The plunger 124′,124″ may have a smooth outer surface to avoid damage to the fluid inflatable containers 140′,140″ and be tapered to allow smooth motion. The vane 120 and the plungers 124′,124″ are subjected to large forces as they transmit mechanical force to the fluid inflatable containers 140′,140″, and so it is preferred if the plunger 124′,124″ is capable of withstanding large amounts of force on the sides and bottom without significant or permanent deformation. The forces on the plunger 124′,124″ will be directly related to the pressure created in the fluid inflatable container 140′,140″ and the surface area of the fluid inflatable container 140′,140″ in contact with the plunger 124′,124″. A single-plunger vane assembly may be created by substituting two plungers 124′,124″ with a single, “two-headed” plunger. The two-headed plunger may be a single assembly and may include the vane 120 and be connected directly to the shaft 116.
The arcuate motion received by an embodiment of this invention is not limited to a circular path as shown in the drawings. So long as the motion of the plunger 124′,124″ is guided through an arcuate path similar to the curvature of the enclosure surrounding the fluid inflatable containers 140′,140″, the mechanical energy can be converted into fluid power. The movement and curvature of the enclosure can be similar in shape. The acceptable mechanical energy input arc is based upon the movement of the shaft 116, movable member, or non-stator portion of the actuator. The mechanical input or energy may be arcuate or linear and it may be reciprocating or non-reciprocating.
Various non-linear mechanical input is acceptable including crescent shaped, oval shaped, rotary, curves and other irregular patterns. The fluid inflatable container 140′,140″ may be charged with varying amounts of non-volatile gas or fluid. In an embodiment, the fluid may be air, water (including but not limited to groundwater, river water, seawater, brackish water, glycol-water mixes), gas, oil, high-density fluid, high-pressure hydraulic fluid, electro reactive fluid, and high viscosity fluid. In an embodiment, the fluid may contain suspended magnetic particles such that when the fluid passes a coil of wire, a current flow is induced in the coil. In another embodiment, the fluid may be conductive such that when the fluid passes an electromagnet, a current flow is induced in the fluid.
Referring now to FIGS. 9A, 9B and 9C, shown are side and frontal views of various exemplary spring arrangements that may be used to stabilize the shaft 116, to bias the system in a given orientation. In FIG. 9A, an embodiment is shown which employs two torsion springs 700′ and 700″ to stabilize the shaft 116 with relation to the drum 104. The spring or springs 700′ and/or 700″ can also be used to tune the resonant response of the entire system for collecting energy (not shown). By adjusting the spring constant and pre-load of the springs 700′ and/or 700″ and the pressure at which the system operates, the natural resonant frequency of the entire system can be tuned. In FIG. 9B, torsion springs 710′ and/or 710″ are shown stabilizing the shaft 116 in relation to the drum 104′. In FIG. 9C, the system is shown with power springs 730′ and/or 730″ positioned in relation to the drum 704.
Referring now to FIG. 10A and 10B, shown are side and frontal views of an exemplary rotating assembly 804 for use in an embodiment of the system for converting mechanical energy to fluid power, respectively. The rotating assembly 804 is an example of a component that can be used for bearings in system 100.
Referring to FIG. 10B, shown are three or more casters 440 mounted on the drum 104 (not particularly depicted) and arranged such that the shaft 116 is supported and can freely rotate in the center of the drum 104. Each of the casters 440 is attached to the rotating assembly 804 with one or more bolts 442. Each of the casters 440 is directly or indirectly attached to the drum 104. The rotating assembly 804 may be mounted outside of the drum 104, on an outside surface such as an end cap of a drum 104. The rotating assembly 804 may also be mounted inside the drum 104 on the inside of an end cap of the drum 104, for example. The rotating assembly 804 may also be connected to the drum 104 by a frame holding the rotating assembly 804 in place.
The casters 440 may be easily removed for field service. A caster 440 can be more easily replaced when it is not in contact with the shaft 116. In one embodiment, one or more casters 440 is adjustable so that it may be moved away from the shaft to create a small tolerance within which the shaft 116 may be moved radially away from each of the casters 440. In this manner, casters 440 may be replaced one at a time. In another embodiment all of the casters 440 are adjustable and the rotating assembly is integrated into the endplate of the system 100, the shaft 116 is moved by employing a conventional hydraulic or mechanical jack. The jack can be removed once a caster 440 is replaced and the one or more adjustable casters are tensioned to firmly hold the shaft 116 in position. The shaft 116 typically runs radially through the central axis of the drum 104. The casters 440 can be replaced without disassembling the rotating assembly 804 or removing the shaft 116 and without removing other casters 440. Given the very harsh conditions that a system 100 is expected to operate in, the rotating assembly 804 provides a low-cost method of providing a bearing, while also offering easy serviceability.
Referring now to FIG. 11A, shown is an embodiment of a prior art system for converting the energy of reciprocating ocean wave energy into fluid power. The prior art system 600 consists of a wave attenuating wall 840 which is connected to a frame 826 on the seafloor, by a hinge 827. As the wall 840 reciprocates, a hydraulic piston 825 connected to the wall 840 is forced back and forth within a hydraulic cylinder 820 mounted on the frame 826. The reciprocating mechanical motion of the ocean waves is thus converted into fluid power which can be used for power generation or other useful purposes. A drawback of this prior art is the reliance on conventional hydraulic cylinders which are ill suited to long-term use in the hostile undersea environment.
Referring now to FIG. 11B, an exemplary system 700 utilizing an embodiment of the apparatus for converting mechanical energy into fluid power 100 is shown applied for the conversion of ocean wave or current power into fluid power. In this embodiment the system 100 converts the reciprocating motion of ocean waves (not shown) into fluid power by the use of a flap 840 hinged to a frame 826 anchored to the sea floor (not shown) and extending through the surface of the water. In one embodiment, the shaft 116 is fixed to the frame 826 while the drum 104 is fixed to the flap 840. In another embodiment, the drum 104 is fixed to the frame 826, while the shaft 116 is fixed to the flap. In either embodiment, relative mechanical motion is created in the converting system 100 to move fluid. In one embodiment, the shaft 116 of the system 100, is turned by the action of the waves against the flap 840, which alternately compresses the fluid inflatable containers (not shown) to create a bidrectional flow of fluid power or, when coupled to a valve manifold with an appropriate arrangement of one-way valves (not shown), a unidirectional flow of fluid power. The fluid power may be used to power a hydraulic motor or turbine (not shown) coupled to a generator (not shown), and may thus generate electricity. The pressurized fluid may also be used to compress seawater for reverse osmosis desalination.
FIG. 11B shows two drum-shaped converting systems 100 one on each end of the wall. Any number of drum shaped converting systems 100 may be used, for example one in the center of the wall or three with one in the center and two on the ends or outer portion of the wall. In larger embodiments, four or more converting systems 100 may be used. Each of these systems 100 may be connected to a hydraulic motor or turbine (not shown) or multiple systems 100 may be connected to one hydraulic motor or turbine.
Referring now to FIG. 12, an apparatus for absorbing and converting tidal energy 1200 is shown fixed to the seafloor. An embodiment of the converting system 100 is shown with the shaft coupled to a wave flap 840 anchored to the seafloor. The flap 840 absorbs tidal energy 1000 in two directions, incoming and outgoing, and causes the plungers (not shown) to alternately compress one of the two fluid inflatable containers (not shown). The alternate compression of the fluid inflatable containers creates a bidirectional flow of fluid power or, when coupled to a valve manifold with an appropriate arrangement of one-way valves (not shown), a uni-directional flow of fluid power. The resulting fluid power may be used to power a hydraulic motor or turbine (not shown) coupled to a generator (not shown), or for other useful purposes as described herein. Many variations of the apparatus for absorbing and converting tidal energy 1200 using the converting system 100 are available. For example, more or less wave flaps 840 may be used, various means of fixing the apparatus 1200 to the sea floor are possible, any number of converting systems 100 may be connected and used, and the converting systems 100 may be operably connected to one or more turbines (not shown).
Referring now to FIG. 13A, the prior art of a sea surface system 1100 of tethered buoys 1120 used for converting the motion of surface ocean waves into fluid power is shown. The motion of the surface waves causes each of the tethered buoys 1120 to move relative to one another and this mechanical motion is used to generate fluid power. For a more specific description of this prior art sea surface system 1100 see WO/2004/088129. A drawback of this prior art sea surface system 1100 is the reliance on conventional hydraulic cylinders mounted at the junctions of the tethered buoys (not specifically shown) to convert the mechanical motion of the tethered buoys 1120 into fluid power. Conventional hydraulic cylinders are not well suited to prolonged service submerged in a marine environment.
Referring now to FIG. 13B, an embodiment of the converting system 100 is mounted at the junctions of a chain of linked, tethered buoys 1120, which float in the waves on the surface of the ocean. The buoys move relative to one another as they absorb ocean wave energy, which in turn causes the shaft 116 of the system 100 to rotate compressing the plungers 124 alternately into the fluid inflatable containers (not shown). The resulting fluid power can then be used for electric power generation as explained herein or for other useful purposes as described herein. The converting systems 100 may be arranged in horizontal or vertical planes between or connected to two of the tethered buoys.
Referring now to FIG. 13C a more detailed depiction of location of the invention at the linkages of a series of tethered buoys 1120′,1120″,1120″' is shown. The invention is positioned to capture mechanical energy from the ocean waves which force the buoys 1120′, 1120″,1120″' to reciprocate up and down and horizontally relative to one another. In the embodiment shown, each tethered buoy is connected to the next with two separate systems 100. One system 100 is placed in a horizontal orientation and one in a vertical orientation. A shaft 116 connects the two systems. In an embodiment a frame or bracket connects the shaft 116 of one system 100 to a system 100 on an adjacent buoy so that upon relative motion of the two adjacent buoys mechanical energy from waves is transferred and causes the shaft 116 of each system 100 to rotate. In this configuration, mechanical motion from at least two directions is captured and the energy converted into fluid motion. In another embodiment, in which only one converting system 100 is used between buoys, a horizontally placed system 100 is located between buoys 1120′ and 1120″, and a vertically placed system 100 is located between buoys 1120″ and 1120′, In one embodiment, the shaft 116 is connected to one buoy, while the drum 104 is connected to the adjoining buoy. The buoys move relative to one another as they absorb ocean wave energy, which in turn causes the shaft 116 to rotate compressing the plungers 124 alternately into the fluid inflatable containers (not shown). The resulting fluid power can then be used for electric power generation as explained herein or for other useful purposes as described herein.
As shown in more detail in FIG. 14, regardless of the source of the mechanical motion, the reciprocating motion and mechanical force (not shown) upon the moveable member (not shown) is translated to rotary motion by the system 100 either by rotating the drum 104, or the shaft 116. This relative motion of or between the drum 104 and shaft 116 causes the plungers 124′, 124″ to compress the fluid inflatable containers 112′, 112″ generating alternating flows of fluid from one fluid inflatable container 112′, 112″ to the other 112, 112″ through hoses 300 to the manifold 250. As the fluid (not shown) flows through the manifold 250 individual check valves (not shown) convert the reciprocating fluid flow into uni-directional flow through the hydraulic motor or turbine 270 which drives an alternator 280 to produce electric current (not shown) which is transmitted wherever desired. In one embodiment, fluid is stored in a reservoir (not shown) and flows between the reservoir and the containers 112′, 112″ and does not flow between the two inflatable containers 112′, 112″.
The system to generate electricity of FIG. 14 is monitored by a computing system 230 which receives data from multiple sensors 232 and which may control the flow of fluid through the system using electronically actuated variable valves (not shown) and thus controlling the speed of the hydraulic motor or turbine 270. In one embodiment, the computing system 230 is used to increase or decrease the pressure of the fluid in the inflatable containers 112′, 112″. With sensors such as 232, the computing system 230 can in real-time and substantially instantaneously change the pressure in the inflatable containers. This can be done by the computing system 230 controlling the valves (not shown), the turbine or an accumulator. If the computing system 230 software (not shown) learns from a sensor 232 that the velocity of the fluid flow is higher than desired or lower than desired, it can quickly change the pressure (up or down) and increase or decrease the velocity of the fluid flow. In one embodiment, computing system 230 and its software improves the performance and efficiency of the overall systems to generate electricity. In an embodiment multiple systems 100 can be arranged to collect energy from different points on the seabed and transmit pressurized fluid to a single turbine 270 and alternator 280 for power generation. This reduces the need for multiple turbines 270 and alternators 280 as well as other related components.
Referring now to FIG. 15, a schematic of an exemplary valve manifold 250 is shown for converting the alternating fluid flow from the system for converting mechanical energy to fluid power 100 into uni-directional flow. A series of check valves 255 are arranged as shown so that flow from a fluid inflatable container (not shown) passes from a port in the system for converting mechanical energy to fluid power 100, into and out of the manifold through hoses 300. By action of the check valves 255, the fluid is channeled in a single direction through the hydraulic motor 400 or turbine 270 and returns to the opposite fluid inflatable container (not shown) through the manifold 250, and hose 300. In an embodiment, several systems 100 may feed into a single manifold and power a single hydraulic motor 270, thereby reducing the complexity of the overall power collection system. The use of such an arrangement of check valves and other components is discussed in the prior art. For a detailed description of such hydraulic circuits see FIGS. 11a, 11b & 12, in PCT/GB2004/0001443 and the accompanying discussion in the specification therein which is hereby incorporated by reference.
Referring to the next FIG. 16 an alternative embodiment is shown which incorporates an accumulator 260 and charging circuit 600, including a flow limiting valve 620 to limit and smooth out the flow through the turbine 270 or hydraulic motor 400 to produce a more constant speed output and thereby improve the quality of the electricity (not shown) produced by the alternator (not shown). Additional hydraulic and electrical circuits of conventional types may be used to further condition the electrical output of the system. For example, the use of a flywheel to smooth the output of the electric power generator is discussed in PCT Publication No. WO2006/100436, published Sep. 28, 2006. Additional software and controllers may be used to control, monitor, smooth and improve system performance.
Patent Application
20130152566
