Submerged hydroelectric turbines having buoyancy chambers

The present invention generally relates to the field of turbines or power plants that utilize the flow of water to generate electricity. This flow of water includes one-way ones such as those found in rivers or ocean currents, and bidirectional ones such as tidal currents. More specifically, the present invention relates to a device including a large propeller type rotor having an annular outer rim, which is arranged in a large annular housing, and causes the rotation of the rotor to be caused by a fluid flow. More specifically, the present invention relates to a device for immersing a turbine in water.

The production of electricity using hydroelectric turbines is well known. Turbines are typically installed in dams where the flow of fluid under control causes the rotation of propeller rotors or blades. Such a condition in which the water flow is relatively steep is known as a high head condition. It is also known that turbines are placed under low head conditions formed in the bay, estuary or offshore by tidal currents.

Most turbine configurations include a central rotating shaft that is fitted with blades or runners while also known to open the central part of the turbine, which is also known as a rim mount turbine. Has been done. Turbines with a centrally open rotor are particularly effective in low head conditions, i.e. more gradual flow, in which blades are mounted between the inner and outer annular rings or rims to the annular housing that holds the rotor. On the other hand, energy is transmitted through the outer rim.

An example of a rim-mounted turbine with an open center is US Pat. No. 5,592,816, issued January 14, 1997 and reissued as RE38336 on December 2, 2003, on November 18, 2003. U.S. Patent No. 6648589 issued, U.S. Patent No. 6729840 issued on May 4, 2004, and U.S. Patent Application Publication No. US2005 / 0031442 published on February 10, 2005 (US Patent Application No. 10). / 633865) can be found. Examples of hydroelectric turbines used in low head (tide) conditions include US Pat. No. 4421990 by Heuss et al., US Pat. Nos. 6168373 and 6406251 by Vauthier, UK patent application GB2408294 by Susman et al., And Davis et al. It can be found in the international publication WO03 / 025385.

<p> Fluid-driven turbines are considered an environmentally safe alternative to power plants that utilize fossil fuels or nuclear energy. Large-scale power generation using wind power or hydraulic power, which enables power supply in industrial complexes, urban areas, urban areas, etc., requires the installation of a large number of turbines, and these turbines are generated by each turbine. In order to maximize the amount of power generated, it must be large enough to be realistic. The rotor blades of these turbines vary in length, and some experimental designs have blades longer than 50 meters.</p><p> Increasing the length of rotor blades creates structural and manufacturing problems not encountered with smaller turbines or generators. With shaft-mounted turbines, it is difficult to install strong and lightweight long blades. According to the rim mount turbine, this problem is solved by providing an outer support rim as an annular support for each end of the blade, which is held inside a housing with an annular slot or channel. For power generation, a number of magnets are spaced along the annular support rim and a number of coils are spaced along the accommodation channel of the stator housing. The magnetic field formed by the rotor field crosses the gap separating the rotor and the stator. The rotation of the rotor changes the magnetic flux link with the coil, and an electromagnetic force is generated in the coil.</p><p> Since the rim mount turbine does not have a shaft or axle for the central support, the weight of the rotor rests on the lower half of the housing. For large turbines, the effects of such loads and the resulting friction are significant on both the start of the rotor in the housing and the overall efficiency of the turbine after it has started rotating. An increase in rotor weight means an increase in resistance to rotation, which means that a stronger flow of fluid is required to overcome the inherent inertia and friction. This is of particular concern for hydroelectric turbines used under low head conditions.</p><p> It is an object of the present invention to provide an improved structure for a hydroelectric turbine that reduces the weight of the rotor so that buoyancy acts on the rotor. Further, for a rotor immersed in water, a turbine in which the reduction of gravity is achieved by providing a buoyancy chamber in the rotor so that the adverse effects of gravity resulting from the heavy weight of the rotor are reduced or counteracted by the increase in rotor buoyancy. The purpose is to provide.</p>

<p> The present invention is an improved fluid drive turbine in the form in which the rotor blades are supported by an outer rim, the outer rim being held inside or housed in a housing having a channel to receive it. In a typical configuration, the turbine is a generator in which magnets are placed on the outer rim of the rotor and coils are placed in the channels of the housing or stator, producing electricity by rotating the rotor within the stator. In particular, this turbine is of the type to be immersed in water.</p><p> Improvements to the present invention include providing a buoyant rotor inside the housing. In a preferred embodiment, the turbine rotor comprises one or more buoyancy chambers on the annular outer and / or inner rims and / or blades to reduce the overall weight of the rotor and increase the buoyancy of the rotor. .. This buoyancy chamber can be filled with air and other gases, liquids, foams, solids, and any other material with a specific gravity of 1 or less. The buoyancy chamber may be filled with polymer foam, thereby adding structural integrity and rigidity to the rotor.</p>

<figref num="1">It is a figure which shows the typical center open type rim mount turbine which includes the rotor which has the outer rim, and the stator housing which has the channel which receives the outer rim of this rotor, in the state which looked at the axial direction.</figref><figref num="2">It is a perspective view of the stator housing.</figref><figref num="3">It is a perspective view of a rotor.</figref><figref num="4">It is a partial sectional view of the annular outer rim of a rotor.</figref><figref num="5">It is a partial cross-sectional view of a stator housing.</figref><figref num="6">It is a partial sectional view of the annular inner rim of a rotor.</figref>

Hereinafter, the present invention will be described in detail with reference to the drawings in terms of the best and preferred embodiments. The present invention, in one of its broadest significance, is a hydroelectric turbine of the type submerged in water, the turbine comprising a rotor installed inside a stator housing. The rotor has an annular outer rim housed or held by an annular channel or slot in the stator housing and is configured to be buoyant. Other power generation means may be employed, but the power generation means shown herein is in a number of magnets located on the annular rim of the rotor and inside the stator housing, preferably in a channel that houses the annular rim of the rotor. It is configured by combining a large number of arranged coils. For illustration purposes, the turbine is shown in the drawings as a centrally open rim mount rotor, where all support structures for the rotor are formed by a stator housing, but the present invention provides shaft mount rotors with an annular outer rim. It can also be applied to the provided turbine. The term "buoyant", as used herein, means that the described element, whether fresh water or seawater, does not submerge in the type of "water" that immerses the element. And. Regarding the scientific definition of "buoyancy" as having a specific gravity of 1 or less, it is interpreted here as including the extended range when explaining the situation where the density of "water" is different from that of pure water. It shall be.

As outlined in FIGS. 1-3, the present invention is a turbine or generator 10 with a substantially annular stator housing 30. The configuration of the housing 30 shown herein does not imply any limitation and employs other configurations to allow the housing 30 to move undesirably along the axis for any other purpose. It is also possible to hold the rotating part assembly or the rotor 20 and rotate the rotor 20 around its axis of rotation. The housing 30 includes a pair of holding flanges 31 that form a channel 32 that houses and holds the rotor 20.

The rotating part assembly or rotor 20 includes an annular rim member 23 located inside and an annular rim member 22 located outside. A plurality of props, ie runners or blade members 21, are provided extending between the inner rim 23 and the outer rim 22, and these blades 21 have a rotor that allows fluid movement in the axial direction and along the stator housing 30. Angled or twisted in a known manner to produce 20 rotations. Although the individual number, composition and material composition of the blades 21 can be varied, the blades 21 are preferably configured to be as lightweight as possible without unduely impairing structural integrity. ..

The housing 30 and the rotor 20 constitute a power generation means for generating electricity as a combination thereof. Specifically, a plurality of magnets 41 are arranged on the outer peripheral portion of the outer rim 22, and a plurality of coils 42 are arranged near the inner peripheral surface 34 of the housing 30 or the housing channel 32, so that the housing 30 is the stator of the generator. It is supposed to be. The rotation of the rotor 20 causes the magnet 41 to pass between the coils 42, producing electricity according to known methods.

Due to its size, the turbine 10 is preferably made of a relatively lightweight but structurally strong material. For this purpose, the use of polymers, epoxies, resins and reinforcing fibers as key components of the rotor 20 and housing 30 has been found to be suitable for turbine configurations. Typically, the rotor 20 is mainly composed of the above lightweight material in which the magnet 41 and other elements can be embedded. The rotor 20 is configured to exert buoyancy when submerged.

In one embodiment, one or more buoyancy chambers 60 are provided inside the rotor 20, for example, inside the annular outer rim 22 as shown in FIG. In a preferred embodiment, one annular chamber 60 is stretched over the entire circumference of the outer rim 22, but a plurality of chambers 60 may be formed adjacent to each other or in a vertically continuous relationship. In the case of the plurality of chambers, they are arranged in equilibrium in the circumferential direction so as not to adversely affect the rotation of the rotor 20. It is also possible to improve the rigidity of the outer rim 22 by providing a structural element (not shown) such as a reinforcing material in the buoyancy chamber 60. The buoyancy chamber 60 can be filled with air or other gas, liquid, lightweight solid element, or other material with a specific gravity of 1 or less, most preferably of a material such as a polymer foam. A buoyancy material 61 having a certain structural feature is filled. This polymer foam, exemplified by polyurethane or the like, can be preformed and placed in the buoyancy chamber 60 or injected into the buoyancy chamber 60, with respect to the latter being the inner surface of the buoyancy chamber 60 during the curing process. It is preferable in that an adhesive force with respect to is formed. The rigidity of the foam itself and the bonded interface to the wall of the buoyancy chamber 60 enhance the overall rigidity and structural integrity of the rotor 20. The dimensions of the buoyancy chamber 60 and the selection of the buoyancy material 61 are made so that a buoyancy of a desired size according to individual conditions works. For example, under some conditions it may be preferable to make the rotor 20 slightly lighter, under other conditions it may be preferable to reduce the weight of the rotor 20 to a neutral point with respect to buoyancy, and yet another condition. Now, it is necessary to reduce the gravity of the rotor 20 until it has a positive buoyancy with respect to water so that the rotor 20 floats above the stator channel 32 and all frictional effects occur on the upper part of this channel 32. In some cases it is preferable.

Instead of or in addition to the buoyancy chamber 60 provided on the annular outer rim 22, the buoyancy chamber 60 can be provided inside the annular inner rim 23 and / or the blade 21 as shown in FIG. As mentioned above, the buoyancy chamber 60 of the inner rim 23 and the blade 21 may be filled with air or other gas, liquid, lightweight solid element, or other material with a specific gravity of 1 or less. Most preferably, it is filled with a buoyancy material 61 having substantive structural features such as polymer foam.

In this way, the adverse effects of friction between the rotor 20 and the stator housing 30 due to the outstanding weight of the rotor 20 are reduced or eliminated so that starting is achieved more smoothly and more efficiently. Rotation is possible.

Depending on the situation, for example, if a water turbine is desired, it is preferable to reduce the weight of the stator housing 30 as well. As shown in FIG. 5, one or more buoyancy chambers 60 are provided inside the stator housing 30, and the buoyancy chambers 60 are formed by a polymer foam placed after curing or a buoyancy filler 61 such as any other material described above. It is filled, preferably with a material that adds rigidity and structural integrity to the housing 30. Since the stator housing 30 is a stationary element of the turbine 10, the buoyancy chamber 60 is most preferably located at the top of the housing 30 in order to increase the stability of the turbine 10 in water.

The scope and significance of the present invention will be defined as set forth in the appended claims, as it will be understood to those skilled in the art that the equivalents or substitutions for the elements described above will be apparent to those skilled in the art.