| CLAIMS: 1. A turbine apparatus adapted to generate power from a flow of water, the turbine generator comprising: an elongate pillar having a longitudinal axis extending between a top portion and a base portion, the base portion being adapted to be installed on a submerged surface; a support member having a mounting sleeve at a lower end and a generator housing at an upper end, the top portion of the elongate pillar being telescopically received within the mounting sleeve on a bearing mechanism that allows the support member to pivot about the longitudinal axis and slide along the longitudinal axis relative to the elongate pillar; a floatation device mounted on the support member; a generator mechanism housed in the generator housing; and a rotor engaged with the generator mechanism and adapted to rotate about a rotation axis, the rotor having a plurality of arms extending radially from a central hub and a paddle secured to an outer end of each arm, wherein the floatation device is sufficiently buoyant to float the support member above the surface of a flow of water and the rotor arms are sufficiently long to enable the paddles to be driven by the flow of water to rotate the rotor and drive the generator mechanism. 2. The turbine apparatus of claim 1 wherein a guide device is provided at the lower end of the support member, the guide device projecting radially outwardly from the longitudinal axis and adapted to act as a rudder in the flow of water, pivotally aligning the support member such that the rotation axis is substantially perpendicular to the flow of water. 3. The turbine apparatus of claim 2 wherein the floatation device and the guide device are a single component. 4. The turbine apparatus of any one of claims 1 to 3 wherein the floatation device has a profiled teardrop shape in horizontal cross section. 5. The turbine apparatus of any one of claims 1 to 4 wherein the bearing mechanism comprises a ring-shaped ball bearing race and a coaxial ring of roller bearings, the ball bearings adapted to allow pivotal movement of the support member about the longitudinal axis and the roller bearings adapted to allow sliding of the support member along the longitudinal axis. 6. The turbine apparatus of claim 5 wherein the ball bearing race is arranged radially inwardly of the ring of roller bearings such that the ball bearing race contacts the elongate pillar and the roller bearings contact the support member. 7. The turbine apparatus of claim 5 wherein the ball bearing race is arranged radially outwardly of the ring of roller bearings such that the ball bearing race contacts the support member and the roller bearings contact the elongate pillar. 8. The turbine apparatus of any one of claims 1 to 7 further comprising a lifting actuator adapted to raise the support member above the surface of the water flow for maintenance purposes. 9. The turbine apparatus of claim 8 wherein the top portion of the elongate pillar is a hollow cylinder and the lifting actuator comprises an internal piston projecting downwardly into the hollow cylinder of the elongate pillar. 10. The turbine apparatus of claim 9 wherein the elongate pillar includes an injection valve located below the internal piston adapted to receive pressurised fluid to drive the piston upwardly in the hollow cylinder and raise the support member. 11. The turbine apparatus of claim 9 or 10 wherein the internal piston is secured to a mounting plate and the mounting plate is fixed at a flange joint in the support member. 12. The turbine apparatus of any one of claims 1 to 11 wherein the elongate pillar is pile driven into the submerged surface and filled with concrete to install the pillar in place. 13. The turbine apparatus of any one of claims 1 to 11 wherein the elongate pillar is mounted on a pre-cast concrete slab using jacking bolts and a rocker plate. 14. The turbine apparatus of any one of claims 1 to 13 comprising two rotors engaged with the generator mechanism, the rotors being arranged at opposing ends of the generator housing and adapted to rotate about a common rotation axis. 15. The turbine apparatus of claim 14 wherein the generator mechanism comprises a single generator driven by an axel common to both rotors. 16. The turbine apparatus of claim 14 wherein the generator mechanism comprises two generators arranged end to end within the generator housing. 17. The turbine apparatus of any one of claims 1 to 13 comprising two rotors engaged with the generator mechanism, the rotors being arranged at opposing ends of the generator housing and wherein the generator mechanism comprises two generators arranged side by side within the generator housing. 18. The turbine apparatus of any one of claims 14 to 17 wherein the rotors have a corresponding number of arms and the corresponding arms of each rotor are parallel. 19. The turbine apparatus of any one of claims 14 to 17 wherein the arms of one rotor are angularly offset relative to the arms of the other rotor. 20. The turbine apparatus of any one of the claims 1 to 19 wherein each paddle is offset relative to an elongate axis of each arm and is pivotable about the elongate axis between a first position, in which the paddle is generally perpendicular to the rotation axis of the rotor, and a second position, in which the paddle is generally perpendicular to the first position. |
Field of the Invention
The present invention relates to a turbine apparatus and in particular, to a turbine apparatus for generating power from the flow of water, such as a current in a river or tidal inlet.
Background of the Invention
Renewable energy is generated from natural resources such as wind, sunlight, water and geothermal heat, which are naturally replenished. Renewable energy generation allows energy to be produced without depleting limited resources such as coal and oil and without expelling pollutants and greenhouse gases such as carbon dioxide, carbon monoxide and methane.
Wind turbines, which are driven by natural airflows, are a common form of renewable energy generation and typically range from 600kW to 5MW of rated power. However, wind turbine power generation is dependent on naturally variable conditions such as wind speed and direction. Wind turbines can become inoperable, if the wind speed is too low or too high, resulting in intermittent and unreliable energy supply.
Hydroelectric energy is another form of renewable energy that uses the flow of water to drive turbines for generating power. As water is about 800 times denser than air, a far greater output of energy can be derived from a flow of water than for an equivalent flow of air through a given turbine. Natural water flows, such as river and ocean currents, typically tend to provide a relatively reliable and steady flow of water, when compared to air flows in wind, which can vary considerably.
Most hydroelectric power comes from the potential energy of dammed water driving a water turbine and generator. The energy extracted from the water depends on the volume and on the difference in height between the source and the water's outflow, or head. The amount of potential energy in water is proportional to the head. However, the construction of dams to drive hydro-electric power generators is very costly both economically and
environmentally. Aside from the cost of constructing a dam, the damming of a river blocks the movement of fish upstream to spawn and of silt downstream to fertilize fields. In addition, the vegetation submerged by the dammed water decays to form methane, which is a greenhouse gas pollutant.
Low head hydro power applications use water flows such as natural river currents or ocean tidal flows to produce energy. While low head applications typically provide less potential energy, they are able to have far less impact on the natural environment.
Subsurface water turbines are used to generate low head hydro power from water flows by directing water flow through the turbine. As the turbines are submerged, the mechanical and electrical components of the turbine are more susceptible to corrosion and ceasing than dry environment turbines. Subsurface turbines can also be fouled by objects suspended in the water and must be raised for cleaning and maintenance on a regular basis.
Object of the Invention
It is an object of the present invention to substantially overcome or at least ameliorate one or more of the above disadvantages, or to provide a useful alternative.
Summary of the Invention
In a first aspect, the present invention provides a turbine apparatus adapted to generate power from a flow of water, the turbine generator comprising:
an elongate pillar having a longitudinal axis extending between a top portion and a base portion, the base portion being adapted to be installed on a submerged surface;
a support member having a mounting sleeve at a lower end and a generator housing 1 at an upper end, the top portion of the elongate pillar being telescopically received within the mounting sleeve on a bearing mechanism that allows the support member to pivot about the longitudinal axis and slide along the longitudinal axis relative to the elongate pillar;
a floatation device mounted on the support member;
a generator mechanism housed in the generator housing; and
a rotor engaged with the generator mechanism and adapted to rotate about a rotation axis, the rotor having a plurality of arms extending radially from a central hub and a paddle secured to an outer end of each arm,
wherein the floatation device is sufficiently buoyant to float the support member above the surface of a flow of water and the rotor arms are sufficiently long to enable the paddles to be driven by the flow of water to rotate the rotor and drive the generator mechanism.
In a preferred embodiment, a guide device is provided at the lower end of the support member, the guide device projecting radially outwardly from the longitudinal axis and adapted to act as a rudder in the flow of water, pivotally aligning the support member such that the rotation axis is substantially perpendicular to the flow of water. Preferably, the floatation device and the guide device are a single component. Further preferably, the t floatation device has a profiled teardrop shape in horizontal cross section.
Preferably, the bearing mechanism comprises a ring-shaped ball bearing race and a coaxial ring of roller bearings, the ball bearings adapted to allow pivotal movement of the support member about the longitudinal axis and the roller bearings adapted to allow sliding of the support member along the longitudinal axis. Optionally, the ball bearing race is arranged radially inwardly of the ring of roller bearings such that the ball bearing race contacts the elongate pillar and the roller bearings contact the support member. Alternatively, the ball bearing race is arranged radially outwardly of the ring of roller bearings such that the ball bearing race contacts the support member and the roller bearings contact the elongate pillar.
The turbine apparatus preferably further comprises a lifting actuator adapted to raise the support member above the surface of the water flow for maintenance purposes. Preferably, the top portion of the elongate pillar is a hollow cylinder and the lifting actuator comprises an internal piston projecting downwardly into the hollow cylinder of the elongate pillar. Further preferably, the elongate pillar includes an injection valve located below the internal piston adapted to receive pressurised fluid to drive the piston upwardly in the hollow cylinder and raise the support member. The internal piston is preferably secured to a mounting plate and the mounting plate is fixed at a flange joint in the support member.
Optionally, the elongate pillar is pile driven into the submerged surface and filled with concrete to install the pillar in place. Alternatively, the elongate pillar is mounted on a precast concrete slab using jacking bolts and a rocker plate. In a preferred embodiment, the turbine apparatus comprises two rotors engaged with the generator mechanism, the rotors being arranged at opposing ends of the generator housing and adapted to rotate about a common rotation axis. Preferably, the generator mechanism comprises a single generator driven by an axel common to both rotors. Alternatively, the generator mechanism comprises two generators arranged end to end within the generator housing. Further alternatively, the generator mechanism comprises two generators arranged side by side within the generator housing.
Optionally, the rotors have a corresponding number of arms and the corresponding arms of each rotor are parallel. Alternatively, the arms of one rotor are angularly offset relative to the arms of the other rotor.
In a preferred embodiment, each paddle is offset relative to an elongate axis of the arm and is pivotable about the elongate axis between a first position, in which the paddle is generally perpendicular to the rotation axis of the rotor, and a second position, in which the paddle is generally perpendicular to the first position.
Brief Description of the Drawings
A preferred embodiment of the invention will now be described by way of specific example with reference to the accompanying drawings, in which:
Fig.l depicts a turbine apparatus installed in a water flow;
Fig.2 is a partial elevation view of the turbine apparatus of Fig.l;
Fig.3 is a cross-sectional view of a portion of the turbine apparatus of Fig. l;
Fig.4 depicts a pile driven installation of the turbine apparatus of Fig. l;
Fig.5 depicts a concrete slab foundation of the turbine apparatus of Fig. l;
Fig.6 is a cross-sectional view of the floatation and guide device of the turbine apparatus of Fig.l; Fig.7 depicts a bearing mechanism of the turbine apparatus of Fig.l;
Fig.8 is a cross-sectional view of the bearing mechanism of Fig.7;
Fig.9A is a schematic depiction of a generator mechanism of the turbine apparatus of
Fig.l;
Fig.9B is an alternative schematic depiction of a generator mechanism of the turbine apparatus of Fig.l; and
Fig.9C is a further alternative schematic depiction of a generator mechanism of the turbine apparatus of Fig. l.
Fig.lOA is a side view of an alternative turbine apparatus; and
Fig.lOB is an end view of the turbine apparatus of Fig. 10A.
Detailed Description of the Preferred Embodiments .
Fig. l depicts a turbine apparatus 10 adapted to generate power from a flow of water 12. As shown in Fig.2, the turbine apparatus 10 includes an elongate pillar 20 having a longitudinal axis A-A and a support member 30. As shown in Fig.4, the elongate pillar 20 has a top portion 24 and a base portion 26 and as shown in Figs.2 and 3, the support member 30 has a mounting sleeve 32 at a lower end and a generator housing 34 at an upper end. The support member 30 is mounted on the top portion 24 of the elongate pillar 20. The top portion 24 of the elongate pillar 20 is telescopically received within the mounting sleeve 32 on a bearing mechanism 40 that allows the support member 30 to pivot about the longitudinal axis A-A and slide along the longitudinal axis A-A relative to the elongate pillar 20.
A floatation device 50, which also acts as a guide device, is provided at the lower end of the support member 30 and is sufficiently buoyant to float the support member 30 on the surface of the water flow 12. The floatation device 50 projects radially outwardly from the longitudinal axis A-A and is adapted to act as a rudder in the flow of water 12. The floatation device 50 has a profiled teardrop shape in horizontal cross section.
A generator mechanism 60 is housed in the generator housing 34. Two rotors 70 are mounted at opposing ends of the generator housing 34. Each rotor 70 is engaged with the generator mechanism 60 and is adapted to rotate about a common rotation axis B-B. . Each rotor 70 has a plurality of arms 72 extending radially from a central hub 74 and a paddle 76 secured to an outer end of each arm 72. The arms 72 each extend beyond the lower end of the support member 30 during rotation of the rotor 70, so that the paddles 76 are at least partially immersed into the flow of water 12 at the bottom of the rotation. The optimum paddle length, depth and profile, as well as the number and spacing of arms 72, will depend on the particular characteristics of the flow of water 12. Ideally, as one paddle 76 exits the flow of water 12, at least one other paddle 76 enters the flow of water 12 to maintain driving force on at least one paddle 76.
In one embodiment, as depicted in Fig.9A, the generator mechanism 60 includes a single generator 62 driven by an axle 64 common to both rotors 70. Alternatively, as depicted in Fig.9B, the generator mechanism 60 includes twin generators 62 arranged end to end, one associated with each rotor 70, with separate gear boxes. Further alternatively, as depicted in Fig.9C, the generator mechanism 60 includes two generators 62 arranged side by side. Gear boxes for the generator mechanism 60 can be fixed ratio or variable speed to allow for varying flow rates of water. A flywheel and clutch arrangement can also be incorporated for start-up and smoother force transfer.
The base portion 26 of the elongate pillar 20 is adapted to be installed on a submerged surface 14 in a flow of water 12, such as a river, estuary, inlet or in an ocean current. In one embodiment depicted in Fig.4, the elongate pillar 20 is pile driven into the submerged surface 14 and filled with concrete to install the elongate pillar 20 in place. Alternatively, as shown in Fig. 5, the elongate pillar 20 is mounted on a pre-cast concrete slab 80 using - jacking bolts 82 and a rocker plate 84.
Referring to Fig.6, as the flow of water 12 flows around the floatation device 50, the profiled teardrop shape causes the radially projecting floatation device 50 to point downstream, in the manner of a rudder. Since the floatation device 50 projects perpendicularly to the I
7 rotation axis B-B, this pivotally aligns the support member 30 such that the rotation axis B-B is substantially perpendicular to the flow of water 12. In this orientation, the paddles 76 are adapted to be driven by the flow of water 12 to rotate the rotors 70 and drive the generator mechanism 60, which produces an electrical power output. Electrical power output is conducted via an electrical cable that passes internally through the elongate pillar 20.
Alternatively, power can be extracted in other forms such as using hydraulic and/or pneumatic pressure.
Turning to Figs and 8, the bearing mechanism 40 comprises a ring-shaped ball bearing race 42 and a coaxial ring of roller bearings 44. The ball bearing race 42 is adapted to allow pivotal movement of the support member 30 about the longitudinal axis A-A and the roller bearings 44 are adapted to allow sliding movement of the support member 30 along the longitudinal axis A-A. In the embodiment depicted, the ball bearing race 42 is arranged radially inwardly of the ring of roller bearings 44 such that the ball bearing race 42 contacts the elongate pillar 20 and the roller bearings 44 contact the support member 30. In an alternative embodiment, the ball bearing race 42 is arranged radially outwardly of the ring of roller bearings 44 such that the ball bearing race 42 contacts the support member 30 and the roller bearings 44 contact the elongate pillar 20.
Returning to Fig.3, the turbine apparatus 10 further comprises a lifting actuator 90 adapted to raise the support member 30 above the surface of the flow of water 12 for maintenance purposes. The top portion of the elongate pillar 20 includes a hollow cylindrical chamber 92 and the lifting actuator 90 comprises an internal piston 94 projecting downwardly into the hollow cylindrical chamber 92 of the elongate pillar 20. The internal piston 94 is secured to a mounting plate 96 via a ram 95 and the mounting plate 96 is fixed at a flange joint 98 in the support member 30. The elongate pillar 20 includes an injection valve 100 located below the internal piston 94 that is adapted to receive pressurised fluid to drive the internal piston 94 upwardly in the hollow cylindrical chamber 92 and raise the support member 30 relative to the elongate pillar 20 until all of the paddles 76 are suspended above the surface of the flow of water 12. Alternatively, the lifting actuator 90 can be provided as an inflatable diaphragm in the elongate pillar 20.
In one embodiment, the rotors 70 have a corresponding number of arms 72 and the corresponding arms 72 of each rotor 70 are parallel. This arrangement provides a substantially equal and balanced distribution of force from the flow of water 12 on the paddles 76 to each of the rotors 70. This arrangement also provides a greater torque to the generator mechanism 60. Alternatively, the arms 72 of one rotor 70 may be angularly offset relative to the arms 72 of the other rotor 70. This arrangement provides a more constant total force with peak power alternating from one rotor 70 to the other as each arm passes the bottom of the rotation.
As the force transfer from flowing water is greater to that of wind, the gearing in the turbine apparatus can be far greater than a traditional wind turbine, with a far lower rpm of the blades required to create an equivalent electrical power output.
Figs.lOA and 10B depict an alternative turbine apparatus 10 including a rotor 70 having arms 72 with paddles 76 that are offset relative to a longitudinal axis of the arm 76. The offset paddles 76 are pivotally mounted to the arms 72 and are pivotable about the longitudinal axis. The paddles 76 are pivotable between a first position, in which the paddle 76 is generally perpendicular to the rotation axis of the rotor 70, and a second position, in which the paddle 76 is generally perpendicular to the first position. In the first position, the leading edge of the paddle 76 is aligned with the arm 72 and the paddle 76 extends backwards from the arm 72.
During operation, the paddles 76 are arranged in the first position during travel through the air, which will typically be the uppermost 270° of rotation (the upper seven paddles shown in Fig.lOA), minimising air resistance as the paddles 76 are aligned in the direction of travel. The paddles 76 are then pivoted to the second position for travel through the water, which will typically be the lowermost 90° of rotation (the lower three paddles shown in Fig.lOA), maximising the surface area presented to the flow of water. This helps to maximise power output as drag is minimised and the driving force is maximised.
Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other . forms.
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