WO2019144942A1

WO2019144942A1 - Apparatus for creating electrical energy from waterflow

Info

Publication number: WO2019144942A1
Application number: PCT/CN2019/073243
Authority: WO
Inventors: William Henry Richards
Original assignee: Flow Energy (Hk) Limited
Priority date: 2018-01-25
Filing date: 2019-01-25
Publication date: 2019-08-01

Abstract

An apparatus for creating electrical energy from a water flow has a turbine and at least one axial flux magnetic generator associated with the turbine. The generator includes a stator, a rotor and a gear box. The rotor supported by the generator housing for rotation with the turbine. The stator mounted with a stator shaft for rotation by the gearbox, and the gearbox is a planetary gearbox having a ring gear configured for rotation with the generator housing, and wherein the stator shaft and generator housing rotate in different directions.

Description

[Title established by the ISA under Rule 37.2] APPARATUS FOR CREATING ELECTRICAL ENERGY FROM WATERFLOW

TECHNICAL FIELD

The present invention relates generally to an apparatus for creating electrical energy from a water flow.

BACKGROUND ART

A tidal stream generator, often referred to as a tidal energy converter (TEC) , is a machine that extracts energy from moving masses of water, in particular tides, although the term is often used in reference to machines designed to extract energy from run of river or tidal estuarine sites. Certain types of these machines function very much like underwater wind turbines, and are thus often referred to as tidal turbines. They were first conceived in the 1970s during the oil crisis.

Tidal stream generators are the cheapest and the least ecologically damaging among the three main forms of tidal power generation.

The main environmental concern with tidal energy is associated with blade strike and entanglement of marine organisms as high speed water increases the risk of organisms being pushed near or through these devices. As with other renewable energies, there is also a concern about how the creation of EMF and acoustic outputs may affect marine organisms. It should be noted that because these devices are in the water, the acoustic output can be greater than those created with offshore wind energy.

Tidal energy removal can also cause environmental concerns such as degrading farfield water quality and disrupting sediment processes. Depending on the size of the project, these effects can range from small traces of sediment build up near the tidal device to severely affecting nearshore ecosystems and processes.

It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

SUMMARY OF INVENTION

The present invention is directed to an apparatus for creating electrical energy from a water flow, which may at least partially overcome at least one of the abovementioned disadvantages or provide the consumer with a useful or commercial choice.

With the foregoing in view, the present invention in one form, resides broadly in an apparatus for creating electrical energy from a water flow, as set out in any one of the appended claims. Further aspects and forms will be evident from the description and drawings.

The apparatus of the present invention is specifically adapted to the creation of electrical energy from a water flow. Normally, the floating vessel is anchored or otherwise moored relative to a moving water flow, typically a non-tidal water flow such as a river for example. It can be difficult to obtain sufficient energy from the flow of a river or non-tidal flow in order to make it economical to produce electrical power from the flow. The flow of the water will cause rotation of the turbine causing rotation of the turbine shaft and the epicyclic gearbox will typically use the relatively slow rotation of the turbine shaft and convert this into a higher speed of rotation of the generator shaft associated with the at least one axial flux magnetic generator. The inventor has found that a turbine speed as low as 2 rpm can be used to create a stable and efficient electrical power supply generated using the present invention. This apparatus therefore can harness the steady, but relatively slow water flow of the waterway to efficiently convert into electrical energy.

The apparatus of the present invention includes a moored or anchored floating vessel, moored or anchored relative to a water flow, the floating vessel mounting a sealed, watertight, cylindrical turbine with a plurality of turbine blades extending along a cylindrical turbine length, each turbine blade sealed at both ends, the turbine associated with a turbine shaft rotating with the cylindrical turbine.

The floating vessel will normally be moored such that the turbine is oriented substantially perpendicularly to the directional flow. As mentioned, the apparatus of the present invention will normally be used in a river or non-tidal flow and these flows will normally be substantially unidirectional.

The vessel will typically have a pair of spaced apart floats or pontoons relative to which the remainder of the vessel is constructed. Each of the floats or pontoons will preferably be elongate in order to provide stability. The floats or pontoons will normally be spaced apart from one another, typically with the turbine located substantially between the spaced apart floats or pontoons.

The vessel will normally have a superstructure provided above the pontoons with the superstructure mounting the turbine relative to the floats or pontoons. Provision of the pontoons will preferably provide a shaped entryway for the flow to the turbine. The spaced apart pontoons will typically induce a channeling effect in the water flow to the turbine which may assist with a slight speed increase in the water flow due to the channeling of the water between the pontoons.

Each of the floats or pontoons is preferably generally rectangular. Each of the floats or pontoons will typically have an angled entry portion and an angled exit portion with the entry portion angled downwardly and rearwardly in the direction of flow and the exit portion angled upwardly and rearwardly in the direction of flow. Each of the floats or pontoons typically has a substantially planar lower surface and a pair of substantially perpendicularly extending side surfaces, one outer side surface on the side of the float or pontoon opposite to the turbine and an opposed inner side surface located on the side of the float or pontoon closest to the turbine.

Each of the floats or pontoons will preferably have a modular construction, formed from a number of modules which are attached together. Typically, each of the pontoons will have a pair of end modules which are substantially the same but oriented in different directions, and one or more intermediate modules. Each of the modules will typically have a frame construction with the frame manufactured from a number of members attached together to define the overall shape of the module and then with a covering or shell provided about the frame in order to form a closed module. This will provide the modules with the required strength and also reduce weight.

The floats or pontoons will typically be located on opposed lateral sides of the vessel, typically extending or defining the length of the vessel and normally, the floats or pontoons will be generally oriented in the direction of flow relative to the vessel.

The vessel includes a superstructure mounted relative to the floats or pontoons. In a preferred embodiment, the superstructure will be built including a framework having a number of members. The superstructure will typically be configured to allow the turbine to be raised and lowered relative to the waterline in order to raise the turbine above the waterline for transport of the vessel to a desired location or for maintenance or the like and to allow the turbine to be lowered at least partially into the flow in a working position. The turbine may also be raised and lowered relative to the waterline to adjust the depth of engagement of the turbine blades with water flow. This allows the turbine to be adjusted for varying water flow conditions within the river or body of water. In one embodiment the turbine is design to submerge to a maximum depth of around 6 meter into the water.

The superstructure will typically include one or more shaped, transversely extending members or assemblies mounted relative thereto, preferably on an upstream side of the turbine. The transverse members or assemblies are preferably shaped such that each includes an angled portion extending upwardly toward the centre of the vessel from an outer side. This may form a Venturi shaped entryway into the turbine which may result in a small increase in fluid flow to the turbine.

Preferably, the transverse members or assemblies will be provided within the separation distance between the floats or pontoons and therefore, an outer end of the transverse members or assemblies will be located inside the pontoons but outside the end edges of the turbine.

Operational equipment is preferably mounted relative to the superstructure for example a plant room, bridge, any regulation equipment in any electrical connection equipment to connect to an external grid or power store for example.

The superstructure will preferably mount the turbine. The superstructure will also preferably mount at least one generator and at least one gearbox relative to the turbine, preferably coaxially with the turbine.

The turbine will normally be mounted relative to at least one turbine shaft and the turbine shaft mounted relative to the superstructure. The at least one turbine shaft is generally end mounted, that is a bearing mount will normally be provided at both ends of the at least one turbine shaft. Preferably, the bearing mount will be provided outside the end walls of the turbine.

The turbine of the present invention is preferably mounted for use or deployment between the preferred floats or pontoons. The turbine preferably has a turbine body which is cylindrical having a cylindrical surface and a pair of substantially planar, circular end surfaces. The turbine body will typically be substantially hollow in order to reduce weight but the turbine body is preferably sealed with the blades extending from an outer surface of the turbine body. The cylindrical surface and the pair of substantially planar circular end surfaces will preferably close and at least partially seal the cylindrical body.

The turbine includes at least one, substantially centrally extending turbine shaft which preferably acts to both mount the turbine and due to its rotation with the turbine, forms an input into the preferred epicyclic gear box.

The turbine body is typically provided with an internal frame about which the cylindrical surface and end surfaces are provided. The frame is typically formed from a plurality of members and in a preferred form, the frame is an annular frame.

Each turbine includes a plurality of turbine blades. In one preferred embodiment, the bladescan be double curved. It is preferred that each of the blades has a pair of closed ends, preferably substantially coplanar with the circular ends of the turbine body.

Each blade will typically have a substantially linear blade root where the blade attaches or extends from the turbine body generally along the cylindrical surface of the turbine and each blade is then preferably substantially sickle shaped such that the blade tip is in a different radial plane to the blade root.

The preferred closed ends of each blade will preferably form a containment volume. Each blade may include one or more intermediate members in order to brace the curved blade relative to the turbine body, and preferably, a number of intermediate members are provided across the width of the turbine body.

The turbine body may include one or more spokes or spoke assemblies linking on the mounting the cylindrical turbine body frame to relative to the turbine shaft. Preferably, there is at least one intermediate set of spokes or spoke assembly extending radially from the turbine shaft to support the cylindrical turbine body frame partway over the length of the turbine.

The present invention includes at least one axial flux magnetic generator associated with a generator shaft. More than one axial flux generator may be provided. Typically, a pair of generators are provided, one positioned relative to each end of the preferred turbine. Typically, the magnetic generators are located coaxially with the turbine, generally relative to the outside ends of the turbine. A permanent magnet generator is preferred for use as the power generator in the present invention as for its high-efficiency because there is less excitation loss compared to an induction generator.

The permanent magnet generator can be categorized into a radial type and a axial type in terms of the direction of the magnetic flux from the magnet and the generator.

In the radial type, the magnet is positioned on the surface of the rotor that is coupled to the shaft, and the magnetic flux is generated in the radial direction perpendicular to the shaft toward the stator arranged on the outer side of the rotor. In the axial type, the disk shape rotor is coupled to the shaft, and the magnet is positioned on the surface of the disk to generate the magnetic flux parallel to the shaft.

With the radial type, only the magnetic field is used that is generated in the cylindrical gap between the outer stator and the inner rotor so that the output density cannot be increased. Also, with the radial type, in order to increase the magnetic field in gap, magnetic materials such as laminated silicon steel plate is used in the stator side.

Accordingly, the starting performance decreases by the magnetic attraction generated between the magnet and the stator, while the efficiency decreases because of the loss caused by the generation of the alternate magnetic field in the stator side. A possible countermeasure to these predicaments, involves rotor arrangement at the inner and outer periphery, as well as the configuration of the double ring rotor that sandwich the stator without using the magnetic material in the stator side. However, as they are still of radial type, the inner space of the rotor does not contribute to power generation.

On the other hand, the axial type can improve the output density as it can adopt the large magnetic surface by making the rotor dimension thin in the direction of the rotation shaft. By positioning the stator on both sides of the rotor, the magnetic flux on both sides of the magnet can be utilized. In addition, by piling the rotor and the stator in the direction of the shaft, a plurality of the air gap can be applied. As described above, configuring the pile plurality of the rotor and stator creates large air gap in the volume given to the generator, and thereby increases output density. By using this method, instead of increasing the diameter of generator in order to raise the output, the stacking number of rotors and stators can be increased in the axial direction. This also results in an increase in the degrees of freedom of the generator shape.

With the remarkable performance improvement of the NdFeB magnet in recent years, even in a coreless structure that has no magnet material in the stator, it possible to generate high magnetic field. In addition, by stacking the rotor and making the closed flux magnetic circuit, the magnetic field in the gap can be intensified. Moreover, the coreless permanent magnet generator of axial type has neither the cogging torque nor the iron loss of the stator, so one can expect a high efficiency and good starting performance.

The basic preferred structure involves the stacking of the axial gap coreless generator in the axial direction. The rotor coupled to the rotation shaft and the stator fixed to the case is arranged alternatively. A plurality of the permanent magnet is fixed to the rotor with NS alternatively in the ring shape, and the magnetization direction is aligned with that of the neighbouring rotor and generates the magnetic field between the gaps of the rotors. The magnetic field is not only added, but is also increased as the permeance inside the magnet is improved. Also, the rotor arranged at the edge in the axial direction is constructed with ferromagnetic material attached with the magnet in order to suppress the external leakage of the magnetic flux of the magnet. At the same time, recycling the flux increases the magnetic field in the gap, as it is structured to increase the magnetic field in the gap between the rotors by forming the closed magnetic circuit among the magnet of the stacked rotor and the edge back yoke.

The coreless coil is arranged in a ring shape in the stator, and the stator itself is positioned in the gap of the rotor to generate the electromotive force by receiving the alternating magnetic field. As each stator receives the alternating magnetic field of the same phase, the generated voltage can be increased proportionally to the stator number by connecting a coil in series at the same position of each stator.

The increase of the generated voltage is directly related to the increase of the power output, and the generated voltage is proportional to the strength of the magnetic field. Preferably, the gap is as small as possible in order to increase the magnetic field. Additionally, it is preferable to avoid making the thickness of the rotor arranged inside more than that of the magnet, and preferable to make a structure that allows both sides of the stator coil to approach the magnet as often as possible. For that purpose, the rotor has the structure wherein the magnet is embedded in a disk hole made of non-magnetic material, while the stator has the structure wherein the coil is embedded in the disk made of insulating material to avoid generating eddy current. This results in a generator with the stacked magnetic circuit which is smaller, lighter and costs less compared to a plurality of coreless generators being placed side by side simply.

The preferred embodiment generator is designed with 48 poles above has the magnetic pole measuring W 376 mm x H 1740 mm x T 50 mm. A process to incorporate magnets of this size into rotor disks and to stack rotors with a specified gap maintained is required. NdFeB magnets are manufactured by arranging the crystal orientation of NdFeB magnet powder in a particular direction using an external magnetic field, applying mechanical pressure to the mold and sintering it through powder metallurgy. In line with this process, the electromagnet used to apply the magnetic field is incorporated into the press. Due to the limitations of the electromagnet’s performance, the maximum size of a magnet manufactured in one press is approx. 100 mm square. As the pole of the generator is large, it is made by assembling magnet blocks measuring 100 mm x 100 mm x 50 mm. In addition, as NdFeB magnets are fragile, threaded holes cannot be made in them. They are therefore bonded to an iron plate (called the back plate) , which is then bolted to the rotor disk.

Since assembling the magnetized magnet blocks to the rotor disk one by one is intensive in terms of time and labour, separation of the pole into four units and incorporating each of the separated units onto the rotor and bolted them to the rotor disk. The magnetizing process for the magnets requires a magnetic field exceeding 2 T. Magnetic blocks before magnetizing are preferably bedded and bonded to a back plate. Then, the unit is completed by one magnetizing process using superconductive magnetizing equipment. This method is simple and easy compared to magnetizing and fixing each magnet blocks. It is rather difficult to control the unit due to the strong magnetic attractive force toward the rotor in the method where the unit is lowered to the rotor. In addition, the magnetic attractive force generated between the rotors when they are facing finally reaches approx. 2700 kN for a gap of 140 mm, which also makes control rather difficult.

Accordingly, the units can be mounted by sliding them onto the rotor. Despite an attractive force of 10 kN or more between rotor and unit, the unit can be moved with a relatively light force by greasing the area between the rotor and the back plate to reduce friction. In addition, this method enables embedding the units while maintaining the gap between the rotors aligned beforehand so that they face each other. When the units are completely embedded, the rotor assembly is complete. Then, coils are inserted into the rotor gap from the outer diameter side, and the coils are assembled and connected each other to complete the manufacture of the stator.

A single axial-type generator preferably comprises these two rotors and one stator. The generated voltage can be increased by stacking rotors and stators in the axial direction.

Preferably two generators will be provided, one at either end of the turbine mounted coaxially with the main shaft with the gearbox connecting the main shaft and the generator.

The apparatus of the present invention also includes at least one epicyclic gear box associated with the turbine shaft and the generator shaft, the gear box including a sun gear centrally mounted and at least three planet gears, the respective gears configured to cause a speed increase in the rotation of the generator shaft relative to the turbine shaft.

Epicyclic gear sets are relatively well known. The turbine shaft can be associated with the sun gear or a carrier associated with the planet gears and the at least one generator shaft is preferably associated with the other of the sun gear or a carrier associated with the planet gears. Importantly, the gearbox is configured to result in increase in rotational speed of the at least one generator shaft based on the input from the turbine shaft. Therefore, if the turbine shaft is associated with the sun gear, it is preferred that the sun gear is larger, which will cause the planet gears to rotate faster (and the at least one generator shaft is associated with the carrier of the planet gears) and conversely, if the turbine shaft is associated with the carrier for the planet gears, it is preferred that the planet gears are larger, which will cause the sun gear to rotate faster (and the at least one generator shaft is associated with the sun gear) .

It is preferred that the at least three planet gears are each larger than the sun gear to cause a speed increase in the rotation of the sun gear. In a preferred embodiment, the planet gears are mounted relative to the turbine shaft and the sun gear is associated with the generator shaft. Importantly in this preferred embodiment, the sun gear is smaller than the planet gears, meaning that the input from the turbine shaft associated with the planet gears is converted into a faster rotation of the sun gear which drives the generator shaft. Each of the planet gears will normally be mounted relative to a carrier and the turbine shaft is mounted to the carrier.

The planet gears are preferably supported by a carrier such that the planet gears rotate in a coordinated fashion about the sun gear.

A ring gear is also preferably provided about the planet gears. In a preferred embodiment, the ring gear is held stationary which will result in the rotation of the sun gear causing rotation of the planet gears and/or vice versa.

Normally there is a generator at either end of the turbine and each turbine has an intervening gearbox connecting it to the turbine shaft,

At least one pendulum assembly is preferably associated with the ring gear of the epicyclic gear box. If more than one gearbox is provided, a pendulum assembly may be associated with each gearbox. In some embodiments, the pendulum assembly may be or may form a part of the clutch mechanism or alternative, may be provided separately therefrom.

Preferably, the pendulum is configured to hold the preferred ring gear in position or as still as possible or resist momentum which may be induced by the turbine shaft while the sun and the planet gears rotate relative to the ring gear. Preferably, the pendulum will allow a small amount of relative movement but it is preferred that the movement is limited, particularly when the pendulum is associated or a part of the clutch mechanism and the pendulum is used to lock the movement of the ring gear. Typically, the pendulum will include a pair of spaced apart elongate arms with a weighted portion provided at all between the ends of the elongate arms. In this configuration, the pendulum will use gravity to resist movement of the pendulum but as mentioned above, will still allow a small amount of movement.

Preferably, the pendulum is mounted relative to the turbine shaft but associated with the ring gear of the gear box.

The apparatus of the present invention also includes a clutch mechanism to allow slippage between the turbine shaft and generator shaft to assist with build-up of operational rotation speed in the turbine at start-up whereupon once the operational rotation speed has been reached, the clutch mechanism is locked for generation of power.

As mentioned above, at least one pendulum may be provided as a part of or to act as a part of the clutch mechanism. Preferably, the weight of the pendulum in association with the ring gear will allow relative movement of the ring gear to reduce the load on the turbine shaft and generator shaft during start-up, but once operational rotation speed has been reached, the pendulum will act to resist movement of the ring gear thereby locking the rotation of the turbine shaft relative to the generator shaft through the clutch mechanism.

A more advanced clutch mechanism may be provided if necessary or desired.

Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention.

The reference to any prior art in this specification is not, and should not be taken as an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.

BRIEF DESCRIPTION OF DRAWINGS

Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows:

Figure 1 is an isometric view of an apparatus according to a preferred embodiment of the present invention showing the turbine in the elevated, transport condition.

Figure 2 is an isometric view of the apparatus illustrated in Figure 1 with the turbine in the lower end, operational condition.

Figure 3 is a side elevation view of the apparatus illustrated in Figure 1.

Figure 4 is an end elevation view of the apparatus illustrated in Figure 2.

Figure 5 is a schematic diagram of a horizontal venturi for water turbine.

Figure 6 is a second schematic diagram of the horizontal venturi for water turbine.

Figure 7 5 is a schematic diagram of a vertical venturi arrangement for water turbine.

Figure 8 is a 3D diagram of the horizontal venturi according to an embodiment of the present invention.

Figure 9 is a schematic diagram of the horizontal venturi in Figure 5 and 8.

Figure 10 is a top view of the one side of the vertical quad-core venturis showing two orientations according to an embodiment of the present invention.

Figure 11 is a schematic diagram of the one side of the vertical quad-core venturis.

Figure 12 is a schematic view showing the operation of a turbine according to the present invention.

Figure 13 is an isometric view of one embodiment of a turbine wheel according to the present invention.

Figure 14 is an isometric end view of the core of the turbine wheel according to one embodiment of the present invention.

Figure 15 is an isometric view of one set of turbine blades according to one embodiment of the present invention.

Figure 16 is an isometric view of the pontoons of a vessel according to a preferred embodiment of the present invention.

Figure 17 is an end elevation view of the pontoons illustrated in Figure 16.

Figure 18 is a side elevation view of a pontoon such as that illustrated in Figure 16.

Figure 19 is a schematic view of an epicyclic gear box according to one embodiment of the present invention.

Figure 20 is a side elevation view of a pendulum configuration of a one embodiment of the present invention, the location of which is illustrated in Figure 12 and 28.

Figure 21 is a side perspective view of a turbine according to a second preferred embodiment of the present invention showing curved turbine blades.

Figure 22 is a front perspective view of the turbine illustrated in Figure 21.

Figure 23 is a perspective view of a turbine segment of the turbine cylinder according to a second preferred embodiment of the present invention.

Figure 24 is a perspective view of a turbine segment of the turbine cylinder illustrated in Figure 23.

Figure 25 is a side perspective view of the valve in Figure 26.

Figure 26 is a view of a valve to be mounted on the blades in accordance with one embodiment of the present invention.

Figure 27 is a schematic view of the valve mounted on the blades.

Figure 28 is a schematic diagram showing the arrangement of the turbine wheel, gear box, and the alternator.

Figure 29 is a schematic illustration of the axial flux generator rotor and stator stack.

Figure 30 is a perspective view of an alternator housing including three magnetic housings of the rotor mounted therein,

Figure 31 is a perspective view showing planetary gear arrangements.

DESCRIPTION OF EMBODIMENTS

According to a particularly preferred embodiment of the present invention, an apparatus for creating electrical energy from a water flow is provided.

The apparatus of the preferred embodiment includes a moored or anchored floating vessel 10, moored or anchored relative to a water flow (direction illustrated by arrow in Figure 3) the floating vessel 10 mounting a sealed, watertight, cylindrical turbine 11 with a plurality of turbine blades 12 extending along a cylindrical turbine length, each turbine blade 12 sealed at both ends and the turbine associated with a turbine shaft 13 rotating with the cylindrical turbine 11.

The floating vessel 10 will normally be moored such that the turbine 11 sits substantially perpendicularly to the directional flow. As mentioned, the apparatus of the present invention will normally be used in a river or non-tidal flow and these flows will normally be substantially unidirectional.

The vessel 10 will typically have a pair of spaced apart floats or pontoons 14 relative to which the remainder of the vessel 10 is constructed. Preferred pontoons are illustrated in more detail in Figures 16 to 18. Each of the floats or pontoons 14 is elongate in order to provide stability to the vessel. The floats or pontoons 14 are spaced apart from one another as shown in Figures 1 to 4, with the turbine 11 located substantially between the spaced apart floats or pontoons 14.

The vessel 10 illustrated has a superstructure 15 provided above the pontoons 14 with the superstructure 15 mounting the turbine 11 relative to the floats or pontoons 15. As shown in Figure 4, provision of the pontoons 14 provides a shaped entryway for the flow to the turbine 11. The spaced apart pontoons 14 will typically induce a channelling effect in the water flow to the turbine 11 which may assist with a slight speed increase in the water flow due to the channelling of the water between the pontoons 14.

As shown best in Figures 16 to 18, each of the floats or pontoons 14 is generally rectangular. Each of the floats or pontoons 14 has an angled entry portion 16 and an angled exit portion 17 with the entry portion 16 angled downwardly and rearwardly in the direction of flow and the exit portion 17 angled upwardly and rearwardly in the direction of flow. Each of the floats or pontoons 14 typically has a substantially planar lower surface and a pair of substantially perpendicularly extending side surfaces, one outer side surface on the side of the float or pontoon opposite to the turbine 11 and an opposed inner side surface located on the side of the float or pontoon closest to the turbine 11.

Each of the floats or pontoons 14 of the illustrated embodiment has a modular construction, formed from a number of modules which are attached together. As illustrated, each of the pontoons 14 has a pair of end modules 18 which are substantially the same but oriented in different directions and a pair of intermediate modules 19. Each of the modules has a frame construction with the frame manufactured from a number of members attached together to define the overall shape of the module and then a covering or shell is provided about the frame in order to form a closed module. This will provide the modules with the required strength and also reduce weight. The hull sections can be transported by ship, rail or road easily to even the hardest to get places. In a preferred embodiment each

hull sections

18, 19 are the size as a 12-meter shipping container with cam locks incorporated. This enables the pontoon sections to be transported or shipped from a manufacturing site to the desired location of use by known container transport means, and assembled together on site. Although figure 18 shows 4

pontoon sections

18, 19 there may be more or less sections, for example 6 sections as illustrated in figure 1.

The floats or pontoons 14 are located on the lateral sides of the vessel 10, typically extending or defining the length of the vessel 10 and normally, the floats or pontoons 14 are generally oriented in the direction of flow relative to the vessel. The vessel will typically be allowed some freedom of orientation to self-align with the prevailing water flow or can be anchored in a fixed orientation. The degree of freedom position of each of the pontoons may be provided with a downwardly extending elongate fin 101 on its lower planar surface. The fin 101 may be fixed, or in preferred embodiments there are fins or

rudders

101, 102 at the front and rear underside of each pontoon and a steering mechanism for adjusting the angular position of the fins or

rudders

101, 102 for controlling the position of the vessel 10 in the water and relative to the direction of water flow. The steering mechanism may be a hydraulic steering system of a type common in boats and ships and may in preferred embodiments be linked to an auto-steering control system. One or more of a GPS receiver and/or flow-vane may be provided and positioned to provide location and water flow direction signals, which can be received by a steering controller and used to generate a fin or rugger position signal for controlling the angular position of one or more of the fins or

rudders

101, 102. The flow-vane is preferably located in the clear water flow upstream of the turbine to provide a water direction signal dependent on the water flow direction ahead of the turbine.

In the preferred embodiment, the superstructure 15 is built around a framework including a number of members. The superstructure 15 will typically be configured to allow the turbine 11 to be raised and lowered relative to the waterline in order to raise the turbine 11 above the waterline for transport of the vessel to a desired location or for maintenance or the like (illustrated in Figures 1 and 3) and to allow the turbine to be lowered at least partially into the flow in a working position (illustrated in Figures 2 and 4) . In a preferred embodiment the turbine blades may be lowered to a nominal depth D of, say, six-meters in to the water. A hydraulic ram system can be used for raising and lowering the turbine. The hydraulic system is preferably powered by a charged hydraulic accumulator and has a governor mechanism operated by the turning turbine to enable the hydraulics to raise the turbine quickly using accumulator charge.

The superstructure 15 as illustrated in Figures 1 to 4 includes a number of shaped, transverse extending members or assemblies 20 mounted relative thereto, at least some on an upstream side of the turbine 11. The transverse members or assemblies 20 are shaped such that each includes an angled portion extending upwardly toward the centre of the vessel 10 from an outer side. This forms a Venturi shaped entryway into the turbine 11 which may further result in even a small increase in fluid flow to the turbine 11.

As illustrated best in Figure 4, the transverse members or assemblies 20 are provided within a separation distance between the floats or pontoons 14 and an outer end of the transverse members or assemblies 20 is located inside the pontoons 14 but outside the end edges of the turbine 11.

Figure 8 and 9 show the horizontal venturi 310 according to an embodiment of the present invention. The horizontal venturi 310 comprises a cylindrical body 311 having a cross-section as a circular segment. A shaft 312 disposed coaxially with a central axis 313 passes through the whole length of the body 311 and extends from both ends of the body 311 to allow rotation of the horizontal venturi 310 to a certain degree. The horizontal venturi 310 can act as a controller to decrease or increase the revolution speed of the turbine wheel 128.

Referring to Figure 7, the horizontal venturi 310 can be positioned under water at a depth deeper than that of the circumference of the turbine wheel 128 with blades 112 and at about 7 o’clock position relative to the turbine wheel 128 (i.e. behind the turbine wheel 314) . Such arrangement is to create a venturi from 6: 30 o’clock position to 8 o’clock position. When there is water flow in a direction as shown in the arrow, the horizontal venturi 310 can be hydraulically rotated around the shaft 12 by zero degree, and up to 30 degrees relative to the water flow. This increases the torque turning moment arc by up to 120 degrees from 4 o’clock position to 8 o’clock position so there are four blades 112 acting as a 120-degree fulcrum to turn the turbine wheel 128 to achieve a greater turning torque.

Optionally, the horizontal venturi 310 can be removed when velocity of the water flow is too high.

Figure 10 shows the vertical quad-core venturis 410-413 aligning to each other according to an embodiment of the present invention. All four of the venturis are joined together and are adjustable simultaneously from 0 to 30 degrees as shown in Figure 10. The venturis can be mounted on the inside of the hull and are arranged on opposing sides, with each side having the vertical quad-core venturis.

Figure 11 shows each of the venturis 410-313 comprises a rear section 128 of the same length to prevent it from entering into the turbine wheel. The leading edge of each venturi increases in length and are spaced accordingly.

The first venturi 410 is used to prevent water from escaping the front of the wheel and out to each side. It functions to direct water spillage to flow back into the turbine wheel to create an end seal on the turbine wheel to increase efficiency of the turbine wheel and blades. The length of the leading edge 112 of the first venturi 410 is configured to protrude under the hull where it picks up undisturbed water when turned to 30 degrees, as well as to deflect the water back into the turbine wheel.

The second venturi 411, having a leading edge 416 of 250 mm longer than the leading edge 415, functions to allow more water to increase both the volumetric flow and speed being directed into the turbine wheel.

The third venturi 412, having a leading edge 417 of 250 mm longer than the leading edge 416, functions the same as the second venturi 411.

The fourth venturi 413, having a leading edge 418 of 250 mm longer than the leading edge 417, functions the same as the second venturi 411.

The venturis 410-313 are of length of six meters and are positioned to inter-phase with the horizontal venturis. The venturis 410-313 are all angled at about 30 degrees to each end opening of the blades.

Optionally, the venturis 410-313 can be adjusted for water speed control.

Operational equipment is preferably mounted relative to the superstructure 15 for example a plant room or control room 21 and a bridge 22 and any regulation equipment in any electrical connection equipment to connect to an external grid or power store for example.

The superstructure 15 mounts the turbine 11. In the preferred form illustrated in Figure 12, the superstructure 15 will also mount a pair of generators 23 each with an associated gearbox 24 to connect the turbine shaft 25 to the generator shaft, preferably coaxially with the turbine 11 as shown.

The turbine shaft 25 is generally end mounted, that is a bearing mount 26 will normally be provided at both ends of the turbine shaft 25. As illustrated in Figure 12, the bearing mounts 26 will be provided outside the end walls of the turbine 11 and fixed in place with removable end caps 27.

The turbine 11, one form of which is illustrated in Figures 13 and 14 is mounted for use or deployment between the preferred floats or pontoons 14. The turbine 11 has a cylindrical turbine body 28 having a cylindrical surface and a pair of substantially planar, circular end surfaces 29. The turbine body 28 is preferably substantially hollow in order to reduce weight but the turbine body 28 is preferably sealed, with the blades 12 extending from an outer surface of the turbine body 28. The cylindrical surface and the pair of substantially planar circular end surfaces 29 will then close and at least partially seal the cylindrical body 28.

The turbine 11 includes at least one substantially centrally extending turbine shaft 25 which acts to both mount the turbine 11 and due to its rotation with the turbine 11, forms an input into the epicyclic gear box 24.

The turbine body 28 is typically provided with an internal frame 30 about which the cylindrical surface and end surfaces are provided, one form of which is shown in Figures 14. The frame 30 is typically formed from a plurality of members and in at least one form illustrated, the frame 30 is an annular frame.

The turbine includes a plurality of turbine blades 12 which, in the illustrated embodiment, are each associated with a section of the annular frame 30 with a blade 12 provided on every alternating section of the annular frame 30 and mounted relative thereto as illustrated in Figure 15. In the preferred embodiment, each blade 12 is double curved from the blade root to the blade tip. As illustrated, each of the blades 12 has a pair of closed ends 31, preferably substantially coplanar with the circular ends 29 of the turbine body 28.

Each blade 12 has a substantially linear blade root 42 at a first radial plane 43 where the blade 12 attaches or extends from the turbine body 28 generally along the cylindrical surface of the turbine 11 and each blade 12 is then preferably extends in a substantially sickle shaped curve 44 such that the blade tip is in a second different radial plane 45 to the blade root.

The closed ends 31 of each blade 12 form a containment volume and each blade 11 includes a number of intermediate members 32 in order to brace the curved blade 12 to the turbine body 28, are provided across the width of the turbine body 28. The intermediate members 32 also serve to divide the containment volume into smaller volumes and prevent the transverse movement of water or debris along the blade.

The turbine body 28 may include one or more spoke assemblies 33 linking on the mounting the cylindrical turbine body frame 30 to relative to the turbine shaft 25. As shown in Figure 12, there is at least one intermediate spoke assembly 33 extending radially from the turbine shaft 25 to support the cylindrical turbine body frame 30.

The first embodiment illustrated in Figure 12 includes a pair of axial flux magnetic generators 23, one positioned relative to each end of the preferred turbine 11. Typically, the magnetic generators 23 are located coaxially with the turbine 11, generally relative to the outside ends of the turbine 11. A permanent magnet generator is preferred for use as the power generator in the present invention as for its high-efficiency because there is less excitation loss compared to an induction generator.

An axial type generator can improve the output density as it can adopt the large magnetic surface by making the rotor dimension thin in the direction of the rotation shaft. By positioning the stator on both sides of the rotor, the magnetic flux on both sides of the magnet can be utilized. In addition, by piling the rotor and the stator in the direction of the shaft, a plurality of the air gap can be applied. As described above, configuring the pile plurality of the rotor and stator creates large air gap in the volume given to the generator, and thereby increases output density. By using this method, instead of increasing the diameter of generator in order to raise the output, the stacking number of rotors and stators can be increased in the axial direction. This also results in an increase in the degrees of freedom of the generator shape.

As illustrated, two generators 23 are provided, one at either end of the turbine 11 mounted coaxially with the turbine shaft 25 with a gearbox 24 connecting the turbine shaft 25 and each generator 24.

The apparatus of the present invention also includes an epicyclic gearbox 24 such as that illustrated in Figure 19, associated with the turbine shaft 25 and the generator shaft, the gear box 24 including a sun gear 34 centrally mounted and at least three planet gears 35, the respective gears configured to cause a speed increase in the rotation of the generator shaft relative to the turbine shaft.

It is preferred that the at least three planet gears 35 are each larger than the sun gear 34 to cause a speed increase in the rotation of the sun gear 34. In the illustrated preferred embodiment, a carrier 36 mounting the planet gears 35 is mounted relative to the turbine shaft 25 and the sun gear 34 is associated with the generator shaft (removed for clarity but extending out of the plane of the page) . Importantly in this preferred embodiment, the sun gear 34 is smaller than the planet gears 35, meaning that the input from the turbine shaft 25 associated with the planet gears 35 is converted into a faster rotation of the sun gear 34 which drives the generator shaft. Each of the planet gears 35 will normally be mounted relative to a carrier and the turbine shaft 25 is mounted to the carrier 36.

A ring gear 37 is also provided about the planet gears 35. In a preferred embodiment, the ring gear 37 is held stationary (during operation but not necessarily during start up) which will result in the rotation of the sun gear 34 causing rotation of the planet gears 35 and/or vice versa minimising lost energy.

As shown in Figure 12, a pair of pendulum assemblies 38 is provided associated with the ring gear 37 of the epicyclic gear boxes 24. If more than one gearbox 24 is provided, a pendulum assembly 38 may be associated with each gearbox 24. In some embodiments, the pendulum assembly 38 may be or may form a part of the clutch mechanism or alternative, may be provided separately therefrom.

Preferably, the pendulum is configured to hold the preferred ring gear 37 in position or as still as possible or resist momentum which may be induced by the turbine shaft 25 while the sun gear 34 and the planet gears 35 rotate relative to the ring gear 37. Preferably, the pendulum 38 will allow a small amount of relative movement but it is preferred that the movement is limited, particularly when the pendulum 38 is associated or a part of the clutch mechanism and the pendulum 38 is used to lock the movement of the ring gear. Typically, the pendulum will include a pair of spaced apart elongate arms 39 with a weighted portion 40 provided at or between the ends of the elongate arms 39. In this configuration, the pendulum will use gravity to resist movement of the pendulum 38 as shown in Figure 20 but as mentioned above, will still allow a small amount of movement.

As illustrated, the pendulum 38 is mounted relative to the turbine shaft 25 but associated with the ring gear 37 of the gear box 24.

As mentioned above, at least one pendulum 38 may be provided as a part of or to act as a part of the clutch mechanism. Preferably, the weight of the pendulum 38 in association with the ring gear 37 will allow relative movement of the ring gear 37 to reduce the load on the turbine shaft 25 and generator shaft during start-up, but once operational rotation speed has been reached, the pendulum 38 will act to resist movement of the ring gear 37 thereby locking the rotation of the turbine shaft 25 relative to the generator shaft through the clutch mechanism.

Normally, the floating vessel 10 is anchored or otherwise moored relative to a moving water flow, typically a non-tidal water flow such as a river for example as illustrated generally in Figures 1 to 4. The flow of the water will cause rotation of the turbine 11 causing rotation of the turbine shaft 12 and the epicyclic gearbox 24 will typically use the relatively slow rotation of the turbine shaft 25 and convert this into a higher speed of rotation of the generator shaft associated with the axial flux magnetic generators 23. The inventor has found that a turbine speed as low as 2 rpm can be used to create a stable and efficient electrical power supply generated using the present invention. This apparatus therefore can harness the steady, but relatively slow water flow of the waterway to efficiently convert into electrical energy.

In the present specification and claims (if any) , the word ‘comprising’ and its derivatives including ‘comprises’ and ‘comprise’ include each of the stated integers but does not exclude the inclusion of one or more further integers.

Reference throughout this specification to ‘one embodiment’ or ‘an embodiment’ means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases ‘in one embodiment’ or ‘in an embodiment’ in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.

The following paragraphs refer to a second preferred example of the invention.

An alternative embodiment of the turbine 11 is illustrated in Figures 21 and 22 preferably mounted for use or deployment between the preferred floats or pontoons 14. The turbine 111 has a cylindrical turbine body 128, preferably made of turbine segments 143 that are joined together.

A plurality of turbine blades 112 are preferably arranged on the circumference of the cylindrical turbine body 128. The spacing between the blades 112 may be adjusted as suitable. Most preferably the turbine blades 112 are arranged equally spaced on the circumference of the cylindrical turbine body 128. For example, the turbine blades 112 are arranged equally spaced on the circumference of the cylindrical turbine body 128 along the width of the turbine body 128, most preferably along the full width of the turbine body 128.

The number of turbine blades 112 arranged on the turbine body 128 may be varied. In a an example embodiment there are at least 5 turbine blades 112, preferably more than 10 turbine blades 112, and most preferably twelve turbine blades 112 arranged equally spaced on the circumference of the turbine body 128.

The turbine blade 112 comprises a non-planar configuration and preferably a generally curved configuration. Each blade 112 comprises a blade tip 141 at the distal end of the blade 112 and a blade root 144 closest to, and attached, to the turbine body 128 defining an opposite end of the blade tip 141. The blade 112 will typically have a substantially linear blade root 144 where the blade 112 attaches or extends from the turbine body 128 generally along the cylindrical surface of the turbine 111 and each blade 112 is then preferably substantially sickle shaped such that the blade tip 141 is in a different radial plane to the blade root 144. In an example embodiment, the blade 112 is made of a hard and durable material such as, for example, steel.

In an example embodiment, the blade tip 141 is curved to an angle of greater than 20 degrees. In a preferred embodiment, the blade tip 141 is curved at an angle of 30 degrees. The curved blade tip 141, particularly but not exclusively curved to an angle of 30 degrees, provides the advantage of additional outside blade strength and higher

blade efficiency. The curved blade 112 also makes the turbine 111 more hydro dynamically hydrofoil suited to lower water velocity flows. Advantageously, the curved turbine blade 112 exhibits maximum output torque and a high energy efficiency rating.

As shown best in Figures 21 and 22, the turbine 111 has a cylindrical turbine body 28 having a cylindrical surface and a pair of substantially planar, circular end surfaces 129. Typically, there are support bearings 142 on the circumference of the circular end surfaces 129 of the turbine body 28. In a preferred embodiment, there are two moving main support bearings 28 on both circular end surfaces 129, one support bearing 128 on each circular end surface 129. This preferred embodiment eliminates any moving external parts being subjected to a liquid environment, i.e. water.

The design and efficiency of the turbine 111 as described advantageously reduces or eliminates the need for regular or intermittent maintenance and/or replacement parts, thus providing an effective, efficient and cost-effective solution.

With reference to Figures 23 and 24, the turbine 111 preferably has a cylindrical turbine body 128 as previously described, wherein the cylindrical body 128 in an example embodiment is assembled from a plurality of turbine segments 143.

The turbine segments 143 are sealed together forming flexible sealing joints on the inside joints 146, outside joints 147 and the end section 148. The joints are preferably sealed and bolted together to form a water-tight cylinder 128 that advantageously reduces oxidation and creates a buoyant cylinder 28. The sealing and bolting of the turbine segments 143 on the inside 146, outside 147 and end section 148 joints form a cylindrical body 128 that is beneficially buoyant externally with an air-tight compartment.

With reference to Figures 25 to 27, there is provided a valve 200 to be mounted on the curved blades 112 of the turbine 128 which manipulates the water flow (direction illustrated by the arrow in Figure 25) through the blades 112. In a preferred embodiment, the valve 200 is a dual flow anti-siphon valve.

Referring first to Figures 26 and 27, the valve 200 includes a hollow head 2 having a first portion 212 along an axis 210, and a second portion 214 along an axis 220 at an angle of about 120° with respect to the axis 210; a ring 202 around an end 216 of the second portion 214 of the hollow head 210; an elongated cage 220 aligned adjacent the second portion 214 along the axis 220; and a ball 230 movable between an open position and a closed position along the axis 220 within the cage 220, wherein the

axes

210, 220 define a pathway for both air flow and water flow through the blades.

As shown in Figure 26, the first portion 212 of the hollow head 210 may include a flat surface 222 on which an inlet 224 is located and connected to the pathway for air flow and water flow. The flat surface 222 allows the valve 200 to be securely fixed to the blade, as compared to a curved surface, especially during the operation of the turbine. Additionally, the flat surface 222 may be mounted on the blade using various securing elements known in the art, such as nails and screws. The first portion 212 of the hollow head 210 may further include a cylindrical portion 226 having a slanted end which connects the flat surface 222 to the second portion 214 of the hollow head 210.

On the other hand, the second portion 214 of the hollow head 210 may include a slanted end, allowing the second portion 214 to connect to the slanted end of the cylindrical portion 226 of the first portion 212. The end 216 of the second portion 214 may have a slanted surface between the inner and outer surfaces of the second portion 214 such that the ball 230 abuts the end 216 in the closed position, preventing the ball 230 moving out of the hollow head 210. The first and

second portions

212, 214 of the hollow head 210 may be formed integrally, or alternatively, may be formed as different components joined together using, for example, adhesives.

The elongated cage 220 with an opening includes four rods, each having a curved end joined together, forming a space within the cage 220 for retaining the ball 230. In one embodiment, the circumference of the opening is larger than the circumference of the end 216 of the second portion 214 of the hollow head 210 so that the ball 230 is moveable only inside the cage 220 without moving into the second portion 214. Preferably, the cage 220 is cylindrical, allowing the ball 230 to move more freely within the cage 220, compared to other shapes of the cage 220. More preferably, the area of space between each rod covers over 70%of the outer surface area of the cage 220 to allow a better air flow and water flow through the blades.

With continued reference to Figure 26, the ring 202 is positioned around the outside of the end 216 of the second portion 214 of the hollow head 210 and designed to fit in the space between the hollow head 210 and the elongated cage 220 since the circumference of the opening is larger than the circumference of the end 216 of the second portion 214 of the hollow head 210.

Referring to Figure 27, the ball 230 is movable between an open position, where the ball 230 sits at the end of the cage, and a closed position, where the ball abuts the end 216 of the second portion 214 of the hollow head 210, along the axis 220.

In the illustrated embodiment as shown in Figure 27, the valve 200 is provided on the leading edges of two curved blades 112 of the turbine 128. Preferably, the valve 200 is provided on each of the curved blades 112 and incorporated in each section and diversion of all the curved blades 112 such that the applicability of the turbine 128 can be maximised, as will be discussed in the following paragraphs.

As water flows through the blades 112 in the direction as indicated by the arrow in Figure 25, the ball 230 of the valve 200 on the blade 112 contacting the water is in the closed position. This in turn traps water on the blade 112 and facilitates the operation of the turbine 128. When the blade 112, which is full of water, goes up along the direction, the ball 230 of the valve 200 is in the open position, allowing the removal of the trapped water, so as to prevent a suction lock. Then, when the blade 112 continues to travel back to the water, the ball 230 returns to its closed position and stops water passing through the blades 112, and the cycle continues. In addition, the open position of the ball 230 also helps preventing leading edge blades 112 from airlocks in front of the blades 112 by letting all trapped air out of the front of the blades 112. When all trapped air is eliminated as the blade 112 goes down to the water, the ball 230 returns to its closed position. As such, the efficiency of the turbine 128 may be increased using the abovementioned valve 200.

Figures 28 to 31 illustrates a second, preferred, embodiment of an axial flux generator 123 for use on the vessel. The generator 123 is bolted or otherwise affixed to the outside end 129 of the turbine body 128. Two generators 123 are provided, one at each end of the turbine wheel 128. The generator 128 has a generator housing 150 comprising three axially concentric and longitudinally arranged

portions

151, 152 and 153. An inner portion adjacent the turbine wheel 128 comprises a gearbox housing portion 151 the outer surface of which provides a running surface for one or a plurality of wheel support bearings 142. At the opposite end of the generator housing is a bearing housing portion 153 provided a second running surface for a second one or a plurality of wheel support bearings 142. Intermediate the gear housing portion 153 and bearing housing portion 153 is a rotor housing portion 152 for supporting the generator rotor. The generator housing 150 rotates with the turbine wheel 128. The axial flux rotor is supported in the rotor housing portion 152 and rotates with the turbine wheel 128. The rotor comprises a plurality of axially spaced stacked rotor discs 160 as illustrated and discussed in more details with reference to Figures 29 and 30. The generator housing additionally comprises a pair of inwardly extending stator support flanges 164, 165 supporting stator bearing members 166. A stator shaft 170 is axially supported within the stator bearing members 166 by stator bearings 171 so as to be independently rotationally supported at the axial centre of the generator housing 150. The stator shaft 170 supports a plurality of stator discs 172 that extend radially from the stator shaft to locate between adjacent pairs of the rotor discs 160. The stator discs 172 have stator winding with winding tails 175 which take voltage and current induced in the windings to slip rings 178 located on the distal end of the stator shaft 170.

A planetary gearbox 180 is located within the gearbox housing portion 151 generator 123. The planetary gearbox comprises a ring gear 181 that is supported on an inner surface of the gearbox housing 151 and configured to turn with the generator housing 150 and turbine wheel. A sun gear 183 of the planetary gearbox is supported on and configured to rotate the stator shaft 170. A plurality of planet gears 182 meshingly engage between the ring gear 181 and sun gear 183.

A planet shaft 182 extends from the gearbox housing portion to within the turbine wheel 128, and is rotationally support between the proximal end of the rotator shaft 170 and an intermediate spoke assembly 33 extending radially within the turbine wheel 128 on bearings 186, 187. At the distal end of the planet shaft 182 is a radially extending planet support flange 184 on which the plurality of planet gears 182 are rotationally supported about axes 188. A pendulum 30 with a weighted portion 40 is supported by elongate arms 139 at the proximal end of the planet shaft 185. A clutch mechanism is provided to selectively allow slippage between the planet shaft 185 and elongate pendulum arms 139 or to selectively rotationally lock the elongate pendulum arms 139 with the planet shaft 185. Selectively rotationally locking the elongate pendulum arm 139 with the planet shaft 185 causes a high inertia in the planet shaft 185 such that it resists moving with the gearbox housing 150 and thus locks the planet gears 182 relative to the ring gear 181. This engages the planetary gearbox.

The stator shaft 170 and planet shaft 185 are rotationally independent of each other and of the generator housing 150 in which they are supported. As the turbine wheel is lowered into a water flow at start-up of the generator 123 the clutch is selectively engaged to allow slippage between the planet shaft 185 and elongate pendulum arms 139. This allows the stator shaft 170, planet shaft 185 and generator housing 150 to be freely independently rotatable to reduce the load on the generator during start-up. Once operational rotation speed has been reached the clutch is selectively dis-engaged to rotationally lock the elongate pendulum arms 139 with the planet shaft 185. The weight of the pendulum 38 then causes the planet shaft 185 to begin to slow any rotation relative the generator housing 150 and ring gear 181, which in turn starts to engage the planetary gearbox. As the planetary gearbox is engaged the planet gears 182 begin to counter-rotate the ring gear 183 and thus the stator.

The planetary gearbox arrangement provides a counter rotation between the generator rotor and stator to increase the relative speed between the two. For example if water flow achieves 2rpm clockwise rotation in the main turbine wheel and stator and the planetary gearbox is selected to achieve 12 rpm anticlockwise in the Stator giving a total speed increase of 14rpm less gearbox efficiency which is our requirement of RPM for power generation. This way 2 rpm is gained with just the seed of the main turbine 128.

The clutch may be provided in the form of a hydraulic torque limiter which is allowed to slip at a reduced speed till it has reached operating rpm and is then locked for the duration of the generation of power. The hydraulic torque limiter is used to de energized the alternator and is used for servicing main turbine and or repairs. It allows for easier start-up which lets the turbine to build up to operating RPM and inertia before end-gauging the rotating stator. The Hydraulic Torque Limiter is flanged mounted and fixed or driven through a hydraulic cylinder pin-drive coupling to the offset bearing mounted pendulum counter weight that hangs in the down position when the turbine rotates. Weight is adding till the pendulum hangs vertically and transmits the final drive power to the stator.

The hydraulic torque limiter may also be configured to limit the operating rpm of the gear box so as to prevent overloading of the electronic components. In one example, a second hydraulic torque limiter may be connected in between the turbine wheel and the gear box housing. The limiter may be arranged to slip there between so as to act as a clutch to slow down and lock the rotation speed of the ring gear once the gear box has reached the operating rpm. Advantageously, such arrangement allows an easy start-up which lets the turbine to build up to operating rpm and inertia before end-gauging the rotating stator.

With reference also to Figure 29 and 30, there is shown an embodiment of an alternator housing fitted with three magnetic rotor housings 160 as shown in Figure 28. The alternator has an outside section 152 which is directly connected to the main turbine wheel 128 all as one fixed unit. Accordingly, the magnets fix on the magnetic housing rotate in the same direction and speed as the main turbine wheel. On the other hand, the stator is then fixed to a central shaft that is bearing mounted and is then turned in the opposite direction to the magnets via a planetary, speed increasing gearbox.

Preferably, the slots in each of the rotor poles 160 are also aligned according to the N/Spole direction of the magnets, such that the magnetization direction is also aligned with that of the neighbouring rotor and generates the magnetic field between the gaps of the rotors. In addition, the magnetic housing is preferably made of non-magnetic material such that the alternatively aligned magnetic field is not diverted by the housing material.

The stator disks 172 placed in alternate manner adjacent to each of the magnetic housings or rotor discs 160, i.e. four stator disks alternating with three rotor disks. Alternatively, different numbers of stator and/or rotor disk may be included in the alternator. As the outside section the alternator housing (thus all the rotor disks) are connected to the turbine wheel 128, in contrast, the stator disks are connected at the relatively inner section, and further connected to the central shaft of the generator.

The stator disc preferably has a ring shape structure similar to that of the magnetic housing or the rotor and is substantially flat such that it may be positioned in the gap between two adjacent rotor disks so as to generate electromotive force by receiving the alternating magnetic field from the rotor disks on both sides. Preferably, the bearing or the supporting structure of the stator disk may be made of insulating material to avoid generating eddy current during the operation of the alternator.

Preferably, the stator disk includes a coreless structure having a main support bearing and multiple electrical wires running through the bearing. Upon subjected to magnetic field change in response to a relative movement between the stator and the rotor, electrical current and voltage may be generated within the wires. The wires are arranged radially and the ends of the wires may connect to the external components such as brushes. In addition, one or more electrical coil sections may be formed in an outer section of the stator disk, and the coils may aligns with the magnets in the rotor disks and therefore the aligning magnetic flux running through the coils in the outer section of the stator.

As appreciated by a skilled person in the art, the brushes may connects to external cables and transformers such that power generated in the wires may be further transmitted to power supply stations or the main grid for different usages or storage purposes. Preferably, a 3-phase wiring configuration may be applied, which may be more preferable for a 3-phase power supply system or power grid.

Claims

An apparatus for creating electrical energy from a water flow, the apparatus including:

a) a moored or anchored floating vessel, moored or anchored relative to a water flow, the floating vessel mounting a sealed, watertight, cylindrical turbine with a plurality of turbine blades extending along a cylindrical turbine length, each turbine blade sealed at both ends, the turbine associated with a turbine shaft rotating with the cylindrical turbine;

b) at least one axial flux magnetic generator associated with a generator shaft;

c) an epicyclic gear box associated with the turbine shaft and the generator shaft, the gear box configured to cause a speed increase in the rotation of the generator shaft relative to the turbine shaft; and

d) a clutch mechanism to allow slippage between the turbine shaft and generator shaft to assist with build-up of operational rotation speed in the turbine at start-up whereupon once the operational rotation speed has been reached, the clutch mechanism is locked for generation of power.
An apparatus for creating electrical energy from a water flow, the apparatus including:

a) a moored or anchored floating vessel, moored or anchored relative to a water flow, the floating vessel mounting a sealed, watertight, cylindrical turbine with a plurality of turbine blades extending along a cylindrical turbine length, each turbine blade sealed at both ends, ;

b) at least one axial flux magnetic generator associated with the turbine; the generator including a stator and a rotor,

c) the rotor supported by a generator housing for rotation with the turbine,

d) an gear box associated with the turbine and the generator, the gear box configured to cause a speed increase in rotation relative to the turbine;

e) the stator mounted with a stator shaft for rotation by the gearbox, and

f) the gearbox is a planetary gearbox having a ring gear configured for rotation with the generator housing, and wherein the stator shaft and generator housing rotate in different directions.
The Apparatus of any preceding claim wherein the stator and rotor rotate in different directions.
The Apparatus of any preceding claim further including a clutch mechanism to allow slippage between the turbine shaft and generator shaft to assist with build-up of operational rotation speed in the turbine at start-up whereupon once the operational rotation speed has been reached, the clutch mechanism is locked for generation of power.
The Apparatus of any preceding claim further including a planetary shaft associated with the gearbox and a clutch that selectively allows the planetary shaft to rotate or not rotate.
The Apparatus of any preceding claim including a valve associated with one or more turbine blades.
The Apparatus of claims 6 wherein thwe valve is near a root of the blade and iscoinfigured to release traped air, or to release a vaccum, on one side of the blade.
The Apparatus of any preceding claim wherein the turbine and vessel are constructed in modular form for shipment by container carrying means of transport.
The Apparatus of any preceding claim further including a fin or rudder system and sensors to provide signals received by the fin or rudder system for positioning or maintaining position of the vessel.
The Apparatus of claim 10 wherein the sensors include one of more of a GPS sensor or a flow sensor.
The Apparatus of any preceding claim further including a horizontal venturi system associated with the turbine.
The Apparatus of claims 11 wherein the horizontal venturi is supported below and/or dehind a vertical centerline of the turbine.
The Apparatus of any preceding claim further including one or more vertical venturi systems associated with the turbine.
The Apparatus of claim 13 wherein a vertical venturi is located on either side of the turbine in an upstreams (or flow) position and cononfigured to direct a water flow between the the vertical venturis towards the turbine.
The Apparatus of any preceding claim wherein the generator is an axial flux generator having a plurality of axially arranged rotor and stator discs.