US20120087732A1

US20120087732A1 - Simplified Wave Energy Device Without One-way Clutches

Info

Publication number: US20120087732A1
Application number: US12/900,097
Authority: US
Inventors: Dennis John Gray
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-10-07
Filing date: 2010-10-07
Publication date: 2012-04-12

Abstract

This invention is a greatly simplified device for transforming the energy of water waves into useable energy. The invention is a device for transforming the energy of water waves into useable energy comprising two or more buoys or buoys, and structural members connecting buoys, whereby motions of buoys relative to one another generates torque, and a means for transferring torque to one or more generators, and a means by which to enable all generator currents to flow in a single beneficial direction. Novel systems for interconnecting such devices are also described herein.

Description

CROSS-REFERENCES TO MOST RELATED APPLICATIONS


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STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH & DEVELOPMENT

Not Applicable. No others have rights to this patent.

BACKGROUND OF THE INVENTION

Populations grow exponentially, demand for energy is escalating, and political tensions over hydrocarbons are increasing to say the least. In light of these issues the U.S. Department of Energy continues to place renewable energies as a focal point to their program.
When one looks across an open ocean and views the large rolling waves the energy is glaringly obvious. Winds travel for hundreds of miles and beautifully store and compact their energy into waves. The magnitude of energy and density of energy in ocean waves is fairly easy to comprehend. After all, only waves can pitch and roll ships weighing thousands of tons.
To be cost-effective and viable, a wave energy device must be very simple. It must also be strong to survive punishing ocean environments. Last but not least, it must avoid sophisticated components and have any critical components protected from the harsh oceanic environment. Simplicity in design ensures low capital investment, low operating costs, low maintenance costs, and low energy production costs. Ideally, a wave energy system should be complete and demonstrate interconnectivity. An individual device should not require individual mooring systems and individual subsea electric cables to shore. Devices should float on the water surface to extract maximum wave energy and either be capable of withstanding storm events, be towed away when the largest of storms arise, or temporarily sink below water level until storms pass.
Upon review of existing patents one will find that most have addressed only a few of the challenging design requirements mentioned above. Many wave energy patents that have avoided or eliminated the use of one-way clutches have not sufficiently described how they work and how they would actually be built. A patent specification must enable any person skilled in the art or science to which the invention pertains to make and use the same”. Without sufficient descriptions a patent can be deemed invalid. Without addressing all of the challenging design requirements an wave energy device cannot cost-effectively and reliably deliver power. The novel invention presented herein overcomes the above challenges. Particular features not found in prior patent applications make this invention fully viable, useful, and beneficial.

BRIEF SUMMARY OF THE INVENTION

The purpose of this invention is to efficiently and cost effectively transform water wave energy into useful electrical energy with little or no environmental impact. There are numerous advantages of this particular invention in comparison with prior art.
Maximum available wave power, not partial available power, is extracted by this device and it is extracted on both up and down strokes. Torque arms, acting as levers, add mechanical advantage for power output. The refined design ensures that capital costs will be very low and reliability will be extremely high. Critical components are 100% protected from oceanic spray keeping maintenance costs negligible. No reversing gears are utilized and slightly higher gearing ratios are used for significant benefits. The efficiency losses associated with reducing gears is completely eliminated. Reversing gear systems have generators that spin too slowly and are not of large enough diameter. Thus, these generators become too heavy and expensive. Heavy generators inhibit a wave energy device from harnessing energy because the device cannot properly maintain rhythm or resonance with wave motions. Standard gearboxes can and should be utilized instead of reversing gear systems and such gearboxes can come from many suppliers at fairly low prices.
The use of one-way clutches in wave energy devices presents additional efficiency losses and higher costs. It is better to simply reduce the mass moment of inertia of the gearing and generator so that both gearbox and generator can spin in both directions as waves rise and fall. Multiple hinge points make the device stronger in rough seas and/or quartering seas, enables system redundancy, and enables gearboxes and generators with smaller diameters and lower mass moments of inertia. In combination with reduced mass moments of inertia these wave energy devices should have equipment that accommodates the changing direction of a generator's current flow as waves change from up to down stroke. In essence, sensors would recognize when waves change from up to down motion or when a generator's current direction changes. At these moments the electrical paths would be switched or flip-flopped so that a generator's current is ultimately heading in the preferred direction. Modern electrical equipment can have milli-second response times. In one embodiment, as shown in FIG. 3, the electrical lines are switched at the changing of wave strokes so that the outflow paths remain unchanged.
Buoys can be flooded and the device temporarily submerged below water level. A system for interconnecting energy transformation devices is included herein. Interconnectivity creates a truly complete system that eliminates the need for many individual mooring lines, eliminates a considerable amount of electrical cable, and it allows many of units to be towed via a single tugboat. Towing of many units is desirable since many units could potentially be installed or removed all at once. Mass towing also enables production-line maintenance at shoreline. Assembly-line maintenance at shoreline is far less expensive and safer than maintenance or repair performed offshore. In essence, while many other arrays are generating power just one array at a time can be brought in for service.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a plan and side view of a preferred embodiment of the invention where reversing gears and one-way clutches have been eliminated from the design.

FIG. 2 is a plan and side view of a preferred embodiment of the invention where reversing gears, one-way clutches and gearboxes have been eliminated from the design.

FIG. 3 is a drawing of a switch that could accommodate the changing of wave up/down stroke.

FIG. 4 is an isometric view of a two buoy version of the device with many hinge points.

FIG. 5 is a plan view of many devices connected together with an interconnectivity and mooring system.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention can be designed and scaled for any size waves. A preferred embodiment would primarily be constructed of steel or other suitable marine materials. Components of the device include two or more buoys (1) connected by torque arms (2) whereby a pivoting motion is permitted at hinge points (3) that have bushing or bearings. The buoy movements generate torque which drive one or more gearboxes (4) which in turns drives one or more generators (5) at higher speeds for electrical output.
The complex transmission system described in U.S. Pat. No. 7,315,092 is too customized and expensive, reversing gears are not necessary, and reversing gears present unnecessary efficiency losses. Most importantly, the electrical load, or the amount a wave energy device is trying to power, can be controlled such that the moment of inertia of gearboxes and generators can be consumed before a wave reverses direction. For example, electrical load can be electronically increased just as a wave turns from going up to going downward which would stop the gearboxes and generators. Thus, one-way clutches are not necessary. When a gearbox with dual output shafts is used there can be two generators which as shown at the bottom of the device depicted in FIG. 1. These two generators are labelled as generator (6) and generator (7). This dual generator configuration can inherently reduce the mass moment of inertia of the system since two generators with smaller diameters can have less moment of inertia than one generator of larger size and diameter. Another problem associated with the transmission system described in U.S. Pat. No. 7,315,092 is that it does not permit a high enough rotational speed for the generators to work efficiently. As a result, the U.S. Pat. No. 7,315,092 has generators that are too large, too expensive, too heavy, and they therefore inhibit the device's ability to move with the waves and generate power. This is why gearboxes with higher gearing ratios have been used in this invention.
Although it is desirable that wave energy devices be relatively invisible on the horizon, corners/edges of arrays (many units linked together) will likely be marked with traditional lighted buoys. This will ensure that they are visible from ships at night and in fog.
All critical components are enclosed and protected since the buoys (1) themselves function as protective shells. The only exposed moving joints are the bushings/bearings (8) that are properly designed for submersion in salt water. Common propeller shafts of ships have very similar watertight bearings and seals. If desired, and since the torque arms do not rotate in excessive angles, a sleeve (9) can be installed to cover any bushings/bearings from salt water contact. This invention deliberately raises the elevation of the pivot points (10) to above mean waterline. Propeller shaft seals are designed to be used fully underwater but leakage is far less likely with the pivot points, seals and sleeves/boots elevated above waterline. Universal joints or flex joints (11) may be used to ensure that only pure torque enters gearboxes. Nylatron, plastic, or other pad materials (12) can be used at pivot points to ensure the torque arms do not rub or contact the buoy.
In the preferred embodiment the buoys (1) are flattened but in other embodiments the buoys could have a wide range of volumetric shapes. Flattened buoys or buoys enable immediate response to wave motions. Buoys are constructed of thick materials or deliberately weighted in this embodiment such that they float at about mid level. Weights could be made of concrete, other solid materials, or liquid materials. Buoyancy provides an upward force while weight provides a downward force, both of which generate useful torque. As a result, both upward and downward buoy motions result in torque that ultimately drives generators (5). Splitting this torque relatively evenly, vs. twice the torque on just up or down strokes, reduces the cost of the drive train (gearboxes, generators, etc). Without thick buoy plating or weights (13) the resistance of generators (5) and gears would likely cause buoys to “stick” in an upward position upon the first wave crest. At a minimum, the downward movement of buoys would likely be delayed.
As mentioned previously, buoys are connected via torque arms (2). Torque arms may have the capability of automatically extending or retracting themselves via auto-lengthening mechanisms. Auto-lengthening mechanisms can accommodate varying wavelengths as sea conditions change on any given day. Arm length adjustability increases energy production since distances between outer buoys can better match wavelengths on a given day for optimized power output. In a preferred embodiment, one wave energy device within a large array could measure wave heights and wave periods. A computer program could then estimate average wavelengths from the recorded data and instruct all torque arms within that array to lengthen or shorten accordingly. In the preferred embodiment, the auto-lengthening mechanisms are actuated electromechanically but they could also be actuated via hydraulics or other means. Auto-lengthening mechanisms, like the primary bearings, can be protected from saltwater contact by waterproof sleeves.
With wave movements the motion of one buoy relative to the other buoy or buoys creates extremely high torque. Very high torque is a result of the large displacement of a buoy (1) coupled with the torque arm lengths whether the arms are long or short. The high torque is next directly transferred via the torque arms (2) to a shaft which rotates a gearbox (4). Note that gears, chains and sprockets, or other means can serve to transfer torque to one or more generators.
Similar to arrays of offshore wind turbines, electrical processing equipment can take the electrical output of each generator, process and combine it at a central electrical processing station, and send it to shore via a single subsea cable, batteries, compressed air, or other means. In a one embodiment a central electrical processing station is enclosed within a windowless room and located on a barge near the center of an array. The windowless room could be climate controlled and dehumidified to better protect the equipment within the electrical processing station. Alternatively, the central electrical processing station could be located in a subsea pod.
Components of energy transformation devices that are exposed to the elements, which include buoys and torque arms, can be structurally designed for storm and hurricane forces. Offshore oil platforms have similar pontoons and tubulars that are designed for such storms. Many torque arms can be used and they can be laterally braced and/or trussed (14) as well as vertically braced and/or trussed. In a preferred embodiment, if excessively large waves were encountered, the gearbox could automatically disengage via a clutch. Slip clutches (15) such as those constructed of spring loaded frictional discs can be installed to ensure that gearboxes and all remaining drive train machinery can never be over-loaded. This disengagement feature permits wave energy devices to accommodate excessively dynamic conditions without any damaging effects to internal components.
In rough seas, wave energy devices would have a natural tendency to collide with one another within their arrays. Note that any point on an individual device will move through all six degrees of translation and rotation within a wave cycle. Consequently, there is no single point on an energy transformation device that can be “grabbed” or “held” rigidly in an attempt to interconnect them. FIG. 5 shows flexible interconnection lines (15) connected between devices with mooring lines (16) and anchors (17) at the ends of arrays to keeps lines taught and all devices from contacting one another. Items 15, 16, and 17 together create an interconnect system.
Wave energy devices of this type with just two hinge points, as described in U.S. Pat. No. 7,315,092, are not likely to be structurally strong enough to handle waves coming from diagonal direction or “quartering seas” as this is sometimes called. Devices with few hinge points typically have fewer gearboxes and generators with much larger mass moments of inertia. Many torque arms and hinge points are shown in FIG. 4. Many hinge points not only makes the device stronger in rough seas but it enables many gearboxes and generators, a lower total mass moment of inertia in the machinery, system redundancy, and smaller gears which can reduce costs. Smaller gearboxes and gears is just one way that moment of inertia in the drive trains can be reduced which enables lower energy losses. Rotation of generators directly and without gearboxes is another way to reduce inherent energy losses and improve efficiency. With the advent of slow rpm generators, annular generators (18), and direct drive generators we can now eliminate gearboxes in wave energy devices. Previous wave energy devices have not been able to successfully prove the operation of, and thus patent, a truly viable wave energy device without gearboxes. This is now possible when annular or direct drive generators are used. An electronic means by which to control electrical load (19) can be installed to reduce if not eliminate the mass moment of inertia of machinery items between wave up and down strokes. Switches (20) or other means by which to ensure that all current goes to grid in the desired direction or fashion can also be added so that one-way clutches are not necessary. In essence, these switches or other means make the reversing of up/down wave direction irrelevant. A means by which to control electrical load, or any other means by which to control the flexibility of the device about hinge points, further enables the device to stay in sync with wave motions which can improve if not optimize power output.
Patent applications must sufficiently describe a system for the patent to valid. Furthermore, inventions are novel, beneficial, and patentable when they greatly simplify existing inventions and improve efficiency. Adding an item to an existing invention could be considered infringement. Patent laws state that subtracting items, however, can result in new patents. In summary, inventions that result in fewer components, simplified systems, and higher efficiencies are patentable. This is the case in this invention.

Claims

1. A device for transforming the energy of water waves into useable energy comprising two or more buoys, and structural members connecting said buoys, at least two hinge points, whereby motions of said buoys relative to one another generates torque, one or more shafts or other means by which to transfer torque connected to one or more generators, and a means by which to ensure that one or more generator output currents flow in a single useful direction despite the reversing of generator rotation.

2. The device of claim 1 with one or more slip clutches or other means by which to automatically disengage torque at appropriate times.

3. The device of claim 1 with a means by which to control electrical load or otherwise control the flexibility of the device at hinge points.

4. The device of claim 1 whereby one or more transmissions or gearboxes are added which increase the speed of one or more generators.

5. The device of claim 1 whereby one or more structural members are made automatically adjustable in length resulting in improved energy production.

6. The device of claim 1 whereby an interconnect system is included.

7. The device of claim 1 whereby one or more buoys are sufficiently weighted resulting in useful torque during both upward and downward buoy motions.

8. The device of claim 1 with a means by which to temporarily submerge the device when environmental conditions are deemed too onerous.

9. A device for transforming the energy of water waves into useable energy comprising two or more buoys, and structural members connecting said buoys, at least three hinge points, whereby motions of said buoys relative to one another generates torque, one or more shafts or other means by which to transfer torque connected to one or more generators, a means by which to ensure that one or more generator output currents flow in a single useful direction despite the reversing of generator rotation, and a means by which to control electrical load or otherwise control the flexibility of the device at hinge points.

10. The device of claim 9 with one or more slip clutches or other means by which to automatically disengage torque at appropriate times.

11. The device of claim 9 whereby one or more transmissions or gearboxes are added which significantly increase the speed of one or more generators.

12. The device of claim 9 whereby one or more structural members are made automatically adjustable in length resulting in improved energy production.

13. The device of claim 9 whereby an interconnect system is included.

14. The device of claim 9 whereby one or more buoys are sufficiently weighted resulting in useful torque during both upward and downward buoy motions.

15. The device of claim 9 with a means by which to temporarily submerge the device when environmental conditions are deemed too onerous.

16. A device for transforming the energy of water waves into useable energy comprising two or more buoys, and structural members connecting said buoys, three or more hinge points that are elevated above mean water level, whereby motions of said buoys relative to one another generates torque, one or more shafts or other means by which to transfer torque connected to one or more generators, a means by which to protect one or more shaft locations from water penetration, a means by which to ensure that one or more generator output currents flow in a single useful direction despite the reversing of generator rotation, and a means by which to control electrical load or otherwise control the flexibility of the device at hinge points.

17. The device of claim 16 with one or more slip clutches or other means by which to automatically disengage torque at appropriate times.

18. The device of claim 16 whereby one or more transmissions or gearboxes are added which significantly increase the speed of one or more generators.

19. The device of claim 16 whereby one or more structural members are made automatically adjustable in length resulting in improved energy production.

20. The device of claim 16 whereby an interconnect system is included.

21. The device of claim 16 whereby one or more buoys are sufficiently weighted resulting in useful torque during both upward and downward buoy motions.

22. The device of claim 16 with a means by which to temporarily submerge the device when environmental conditions are deemed too onerous.