GB2457027A

GB2457027A - Hydro-power system

Info

Publication number: GB2457027A
Application number: GB0801616A
Authority: GB
Inventors: Alan Henry Walker
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-01-30
Filing date: 2008-01-30
Publication date: 2009-08-05
Also published as: GB0801616D0

Abstract

A hydro-power system 1 comprises a plurality of pivotally mounted vanes 19. The vanes 19 may be mounted on an endless conveyor 11, the vanes 19 and conveyor 11 in combination having substantially neutral buoyancy, or; the vanes 19 may be mounted in pairs on an endless conveyor 11, or; the vanes 19 may be mounted on an endless conveyor 11 and arranged in sets distributed uniformly there around, or; the vanes 19 may be buoyant. The vanes 19 may be positively buoyant. The endless conveyor 11 may be supported by one or two pylons 3, 5 offset from one another in the direction of a local current. The vanes 19 may be arranged in pairs, first and second vanes of the pair pivoting about a common axis, with the first vane on a first side of the conveyor 11 and the second vane on a second, opposite, side of the conveyor 11.

Description

HYDRO-POWER SYSTEM

The present invention relates to a hydro-power system for use in a flow of water, such as a river or tide way It is known to provide a hydro-power system with a series of vanes mounted on an endless conveyor In use, the vanes are displaced by the current and a dynamo, operatively coupled to the endless conveyor, is driven to generate electricity.

PCT/CN2006/000346 discloses a tidal flow power generator in which a series of sails mounted on an endless conveyor are driven by the current. The sails are provided in a channel and a guide member retracts the sails into a closed position to facilitate displacement against the current. The apparatus is arranged such that the current always enters from the same end, so the generator may be unsuitable for use in tide ways. The weight of the sails may apply a transverse load on the endless conveyor GB 1504104 discloses a generating station comprising a plurality of blades carried on an endless conveyor. The station is moored so that if the current reverses, the station can turn around so that the current flows against the front of the generating station.

Again, the blades may apply non-axial forces to the endless conveyor.

PCTIGR2006/000045 discloses a system comprising a series of parachutes attached to an endless chain couple to a generator. The parachutes are mounted on the endless chain to allow the system to operate when the current is reversed. However, debris may become caught in the parachutes and may result in fouling of the drive gear.

Furthermore, the parachutes may apply transverse loads on the endless chain due to variations in the local current.

The arrangement of the vanes in known hydro-power systems may result in the application of transverse or non-axial forces on the endless conveyor. These non-axial forces may cause unnecessary wear and may eventually lead to failure of the endless conveyor.

The present invention, at least in preferred embodiments, sets out to ameliorate or overcome at least some of the problems associated with known hydro-power systems.

Viewed from a first aspect, the present invention relates to a hydro-power system comprising a plurality of vanes pivotally mounted on an endless conveyor, wherein said vanes and the endless conveyor in combination have substantially neutral buoyancy. In use, the vanes are submerged in a body of water, such as a tidal waterway, estuary or river, and the water current acts on the vanes causing them to be displaced The vanes and the endless conveyor in combination have substantially neutral buoyancy when submerged in water. At least in preferred embodiments, the substantially neutral buoyancy of the vanes may reduce the operational loads applied to the system.

Advantageously, transverse loads applied to the system may be reduced since the vanes and the endless conveyor may be effectively self-supporting.

One or more elements having positive buoyancy may be coupled to the endless conveyor at least partially to offset the weight of the vanes and/or the endless conveyor to provide substantially neutral buoyancy. Preferably, however, the vanes are positively buoyant The positive buoyancy of the vanes may at least partially offset the weight of the endless conveyor To provide the desired buoyancy, at least one cavity may be provided in each vane. More preferably, each vane is at least partially hollow. A gas, such as air, or a buoyant material may be provided in the vanes. For example, an expanded foam may be provided in the vanes.

The vanes are preferably movable between an extended position and a contracted position. Preferably, the vanes are pivotable between said extended position and said contracted position. In their extended position, the vanes present a relatively large cross-sectional area and are displaced by the current thereby providing a driving force which may, for example, drive a dynamo. In their contracted position the vanes present a smaller cross-sectional area and may be displaced against the current with relative ease.

The vanes may be shaped so as to present a streamlined profile when they are in their contracted position.

The system may comprise means for pivoting the vanes between their extended and contracted positions. The pivoting means may be an actuator or guide member.

Preferably, however, the vanes pivot in response to the force applied by the water current when the system is in use. The vanes are preferably shaped to pivot between their extended and contracted positions in response to the local flow conditions. The vanes may pivot to their extended position for travel with the flow and may pivot to their contracted position for travel against the flow.

A biasing means may be provided to bias the vanes towards an extended position or a contracted position. Alternatively, one or more guide vanes may be provided for applying a biasing force to the vanes as they travel through the water.

A locking mechanism may be provided for retaining the vanes in an extended or contracted position. The locking mechanism may, for example, comprise an over-centre locking mechanism. Preferably, however, the vanes are adapted to remain in their extended and/or contracted positions in response to the forces applied by the water. The vanes may be adapted to receive one or more locking devices for locking the vanes in their contracted position. The locking device may be used to retain the vanes in the contracted position to enable servicing and/or maintenance.

The vanes are preferably drivingly coupled to a generator, preferably a dynamo.

The endless conveyor may, for example, be a belt or a chain In use, the endless conveyor is preferably maintained substantially honzontal The system may comprise a plurality of endless conveyors For example, the vanes may be supported between two or more endless conveyors Preferably, the endless conveyors extend substantially parallel to each other.

The endless conveyor is preferably carried by at least one pylon A rotatably mounted drive wheel for supporting the endless conveyor is preferably provided on said at least one pylon. The at least one pylon is preferably fixedly mounted The endless conveyor could extend between a pylon and a floating or tethered support. Preferably, however, the endless conveyor is carried by two or more pylons One or more intermediate pylons may be provided.

The endless conveyor is preferably carried by two or more pylons offset from each other in the direction of the local current or prevalent flow Thus, in use, the vanes may travel between the pylons in a direction substantially parallel to the current Preferably, the at least one pylon is operatively mounted on the bed of the body of water in which the system is installed. For example, the at least one pylon may be mounted in a riverbed or seabed.

The vanes are preferably arranged in sets. The sets preferably each comprise two or more vanes. The vanes in each set are preferably pivotable between an extended position and a contracted position. When the vanes are in a contracted position they may be positioned alongside each other and their longitudinal axes may be arranged substantially parallel to the endless conveyor. Conversely, when the vanes are in an extended position, they may be spread apart and their longitudinal axes inclined relative to the endless conveyor. The vanes in each set may all be mounted on a common carrier.

The vanes in each set may extend radially outwardly from a longitudinal axis of the endless conveyor. The vanes in each set may be distributed uniformly around the endless conveyor. Thus, the angular displacement of adjacent vanes about said longitudinal axis may be the same for all of the vanes in a set. A set consisting of two vanes may have an angular displacement of 180° between the vanes. A set consisting of three vanes may have an angular displacement of 120° between the vanes. This arrangement is advantageous since it may help to ensure that the loading on the endless conveyor is axial and may reduce turning or twisting moments applied to the endless conveyor.

Preferably, the sets each comprise one or more pairs of vanes The vanes in each pair may be opposable. The pairs of vanes may be arranged alongside each other.

Preferably, the vanes in each pair are pivotable about a common pivot axis. The vanes in two or more pairs may also be pivotable about a common pivot axis The vanes in each set may be mounted on a carrier member or a common pivot pin. The carrier member or pivot pin is preferably mounted on the endless conveyor. In use, the pivot axis is preferably substantially horizontal. The vanes are preferably pivotable through substantially 900.

The system is preferably provided with a generator operatively coupled to the vanes More preferably the hydro-power system is provided with a dynamo. The dynamo may operatively be mounted above the surface of the body of water in which the system is installed Alternatively, the dynamo may be provided in a watertight casing operatively located below the surface of the body of the water in which the system is installed. Preferably, the dynamo is located at a centre of a drive wheel rotated by the endless conveyor.

A hazard beacon may be provided to alert craft to the presence of the hydro-power system. Alternatively, a series of beacons may be provided along the length of the system.

Viewed from a further aspect, the present invention relates to a hydro-power system comprising a plurality of vanes pivotally mounted on an endless conveyor; wherein said vanes are arranged in pairs. The vanes are preferably operatively pivotable between an extended position and a contracted position. By arranging the vanes in pairs, the loading on the endless conveyor may be reduced. At least in preferred embodiments, the vanes may apply a driving force to the endless conveyor in a substantially axial direction.

The vanes are preferably in an open position when they are extended. Conversely, when the vanes are contracted they are preferably in a closed position.

Preferably, a first pair of said vanes is provided on a first side of the endless conveyor and a second pair of said vanes is provided on a second side of the endless conveyor. The first and second pairs of vanes may be mounted on the same carrier.

Preferably, the first and second pairs are pivotally mounted on the same pivot pin The vanes are preferably arranged ri sets comprising at least one pair of vanes.

The sets may each consist of two pairs of said vanes.

The endless conveyor may be a continuous belt or the like, but is preferably a chain.

Viewed from a further aspect, the present invention relates to a hydro-power system comprising a plurality of vanes pivotally mounted on an endless conveyor; wherein the vanes are arranged in sets and the vanes in each set are distributed uniformly around the endless conveyor. The angular displacement between adjacent vanes in each set is preferably constant The vanes in each set are preferably operatively pivotable between an extended position and a contracted position Viewed from a yet further aspect, the present invention relates to a hydro-power system comprising a plurality of pivotally mounted vanes, wherein said vanes are buoyant The vanes may be mounted on a drive member or an endless conveyor The vanes are buoyant and this may at least partially offset the weight of the drive member or endless conveyor. Preferably, the vanes in combination with the drive member or endless conveyor have substantially neutral buoyancy.

The vanes according to the various embodiments may each have a longitudinal axis The vanes may pivot about said longitudinal axis, for example to feather and/or unfeather them. Alternatively, the vanes may pivot about a transverse axis extending substantially perpendicular to said longitudinal axis. Pivoting about said transverse axis may cause the vanes to move between an extended or open position and a contracted or closed position.

The term vane used herein may refer to a blade, plate, sail or the like A preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying Figures, in which: Figure 1 shows a side elevation of a hydro-power system according to the present invention installed in a tide way; Figures 2A and 2B show plan views of the hydro-power system of Figure 1 with the local current flowing in opposite directions; Figure 3 shows a plan view of the pivotable vanes according to the present invention in a closed position; Figure 4 shows a plan view of part of the pivotable vanes according to the present invention in an open position, and Figure 5 shows a flat elevation of the vanes according to the present invention passing a drive wheel.

A hydro-power system 1 in accordance with the present invention is illustrated in Figure 1 The hydro-power system 1 comprises first and second pylons 3, 5 fixedly mounted on the seabed in a tide way. The pylons 3, 5 are offset from each other in the direction of the tidal flow such that one pylon 3, 5 is directly upstream of the other pylon 3, depending on the direction of tidal flow. The flow direction of the local current is illustrated in Figures 2A and 2B by the arrows A and A'.

The pylons 3, 5 are partially submerged and a beacon 7 is mounted on each pylon 3, 5 above the water level to warn shipping of their presence. A dynamo 9 is fixedly mounted on top of the first pylon 3 above the surface of the water W, although it may alternatively be provided in a waterproof casing below the surface of the water. One or more intermediate idler wheels may be provided along the length of the hydro-power system 1 between the pylons 3, 5. The idler wheels may be mounted on one or more ntermediate pylons.

An endless conveyor 11 is carried by first and second drive wheels 13, 15 rotatably mounted on the first and second pylons 3, 5 respectively below the surface of the water The endless conveyor 11 may be a continuous belt, but in the present embodiment is a chain. The chain is toothed along one side drivingly to engage the drive wheels 13, 15. The first drive wheel 13 is connected to the dynamo 9 by a vertical drive shaft 17.

A plurality of vanes 19 are pivotably mounted on the endless conveyor 11 In use, the vanes 19 are completely submerged and, preferably, are maintained at a sufficient depth below the surface to prevent them being damaged by boats and other craft passing between the pylons 3, 5 One or more screens may be provided around the hydro-power system 1 to protect it from damage and/or to prevent marine creatures being injured by the moving vanes 19 The vanes 19 are hollow and at least partially filled with air such that each vane 19 has positive buoyancy. The positive buoyancy of the vanes 19 supports the endless conveyor 11 along its length Preferably, the vanes 19 and the endless conveyor 11 in combination have substantially neutral buoyancy when submerged in the water W. Thus, the transverse loading applied on the endless conveyor 11 as it extends between the first and second pylons 3, 5 may be reduced. The vanes 19 are preferably shaped so as to not to generate transverse forces as they travel through the water (i.e. the vanes 19 may be dynamically neutral).

The vanes 19 are grouped in sets of four (4) pivotably mounted on a common pivot pin 21 The vanes 19 in each set are arranged in first and second opposable pairs 23, 25 The vanes 19 are each pivotable through approximately 90° relative to the endless conveyor 11 and pivot between an open or extended position and a closed or contracted position The vanes 19 are illustrated in their contracted position in Figure 3 and in their extended position in Figure 4. The ends of the vanes 19 distal from the pivot pin 21 are chamfered such that a V-shaped channel C is defined when the vanes 19 are in their closed position.

Stops 26a-d are mounted at the base of each of the vanes 19 and abut each other when opposing vanes 19 are in their open position The stops 26a-d help to limit the travel of the vanes 19. A swivel check frame 28 is mounted on the endless conveyor 11 at the junction with the pivot pin 21. The frame 28 may stop the pairs of vanes 19 pivoting beyond a 90° position in relation to the endless conveyor 11. The frame 28 is preferably constructed from a plurality of members each having a triangular section and arranged such that the thinner profile of the triangular members is presented to the water current When the vanes 19 are in their closed position, the longitudinal axes of the vanes in each pair are substantially parallel to each other Conversely, when the vanes 19 are in their open position, their longitudinal axes are substantially co-axial.

The pivot pin 21 is preferably arranged substantially vertically, in use, and the vanes 19 pivot about a substantially vertical pivot axis The pivot pin 21 is mounted directly on the endless conveyor 11.

As illustrated in Figure 5, the first and second pairs 23, 25 of vanes 19 are spaced apart from each such that the first pair 21 passes above the drive wheels 13, 15 and the second pair 23 passes below the drive wheels 13, 15 This arrangement helps to ensure that even loading is applied to the drive wheels 13, 15 by the endless conveyor 11. First and second flanges 27, 29 are provided around the circumference of the drive wheels 13, 15 to guide the endless conveyor 11. A series of detents (not shown) may be provided in the first and second flanges 27, 29 to accommodate the pivot pins 25 A series of recesses 31a-d are formed in the upper edges of the vanes 19 for receive U-shaped saddle locks 33. The locks 33 are locatable in the recesses 31a-d when the vanes 19 are in their closed position. Thus, the vanes 19 may be locked in a closed position to allow maintenance or routine servicing of the hydro-power system 1 The vanes 19 may, for example, periodically be descaled by divers.

In use, the vanes 19 move between their open and closed positions depending on their direction of travel relative to the direction of the local current When the vanes 19 are travelling with the current, the water enters the channel C defined at the free ends of the vanes 19 and biases them towards their open position thereby extending them and increasing their profile. The current acting on the open vanes 19 applies a driving force to the endless conveyor 11 causing it to rotate. Conversely, when the vanes 19 travel against the current they pivot to their closed position presenting a relatively small profile and reducing the drag generated as they travel against the current The driving force imparted by the open vanes 19 exceeds the drag generated by the closed vanes 19 Thus, the endless conveyor 11 rotates.

With reference to Figure 2A, the current is travelling from right to left, as represented by the arrow A. The vanes 19 illustrated at the bottom of Figure 2A are displaced to their open position by the current A The open vanes 19 are displaced with the current A and apply a driving force to the endless conveyor 11 Conversely, the vanes 19 illustrated at the top of Figure 2A are displaced to their closed position by the current A The closed vanes 19 are displaced against the current A and trail behind the pivot pin 21.

The transition between the open and closed positions occurs as the vanes 19 travel around the drive wheels 13, 15.

With reference to Figure 2B, the current is reversed and is travelling from left to right, as represented by the arrow A' The vanes 19 illustrated at the bottom of Figure 2B are now travelling against the current A' and are displaced to their closed position The vanes 19 illustrated at the top of Figure 2 are travelling with the current A' and are displaced to their open position and, therefore, apply the required driving force.

It will be appreciated that the endless conveyor 11 rotates in the same direction irrespective of the direction of the current A Thus, if the hydro-power system 1 is located in a tidal estuary, the dynamo 9 will be rotated in the same direction regardless of whether the tide is coming in or going out.

The rotation of the endless conveyor 11 rotates the vertical drive shaft 17 which drives the dynamo 9 to generate electricity. The electricity may be supplied to the required destination, such as an on-shore power-plant, by one or more cables (not shown) In the illustrated embodiment, the endless conveyor 11 rotates in a clockwise direction when viewed from above, but it will be appreciated that the rotational direction may be reversed by reversing the mounting arrangement of the vanes 19.

To cope with larger drive forces, for example those that may be experienced in deep-water installations, a plurality of endless conveyors 11 may be provided. For example, a pair of endless conveyors 11 may be provided A first endless conveyor 11 may be provided above the vanes 19 and a second endless conveyor provided below the vanes 19. Alternatively, multiple endless conveyors may be provided with vanes 19 provided between them One or more idler wheels may be provided for additional stability The hydro-power system 1 has been described as being mounted on the seabed.

However, the system I may be mounted on a riverbed In order to place the system 1 in a fast-current river valley, gorge or canyon, overspill or perforated dams may be provided to deepen the water without reducing the aggregate power of the current. To control the water level, gated sluices may be provided in the dam, or upstream of the system 1.

Upstream sluices may be provided with gates or valves and piped or canalised to discharge below the dam so as to dry out the system 1 for maintenance or alterations.

This arrangement may be used in place of high dams with turbines, since however high the dam only the aggregate current power is available, the slower speed drive wheels 13, of the hydro-power system 1 according to the present invention may be geared to provide the necessary speed and power of turbines.

To protect large marine creatures, and to protect the hydro-power system 1 from damage from such creatures, screens may be provided in the form of metal, plastic or textile nets attached to the anchor cables of beacon-buoys or to similar beacon pylons surrounding the installation. These screens may only be required in open-ocean deep-water applications.

Warning beacon-lights may be arranged in pairs. one green beacon on the ship-lane or open water side and a red beacon on the side of the hydro-power system 1.

It will be appreciated that governments and other operators of submarines may be provided with clearly marked charts; and underwater Asdic-type sound warnings may be installed.

In some cases the endless conveyors according to the present invention may be so far below the surface as to be no danger to normal shipping, but would still present hazards to fishing lines and trawls Thus, warnings would normally be required It will be appreciated that various changes and modifications may be made to the hydro-power system 1 described herein without departing from the spirit and scope of the present invention -10-

Claims

CLAIMS: 1 A hydro-power system comprising a plurality of vanes pivotally mounted on an endless conveyor, wherein said vanes and the endless conveyor in combination have substantially neutral buoyancy 2 A hydro-power system as claimed in claim 1, wherein said vanes are positively buoyant 3. A hydro-power system as claimed in claim 1 or claim 2 further comprising one or more elements having positive buoyancy coupled to the endless conveyor.

4 A hydro-power system as claimed in any one of claims 1 to 3, wherein said endless conveyor is carried by at least one pylon 5. A hydro-power system as claimed in claim 4, wherein said endless conveyor is carried by two or more pylons offset from each other in a direction of the local current.

6. A hydro-power system as claimed in claim 4 or claim 5, wherein said at least one pylon is mounted on the bed of the body of water in which the system is installed 7. A hydro-power system as claimed in any one of claims 4, 5 or 6, wherein, in use, said endless conveyor is substantially horizontal.

8. A hydro-power system as claimed in any one of the preceding claims, wherein said vanes are arranged in pairs operatively pivotable between an extended position and a contracted position.

9. A hydro-power system as claimed in claim 8, wherein the vanes in each pair are pivotable about a common pivot axis.

10. A hydro-power system as claimed in claim 9, wherein, in use, said pivot axis is substantially horizontal 11 A hydro-power system as claimed in claim 7, 8 or 9, wherein a first pair of said vanes is arranged alongside a second pair of said vanes.

12 A hydro-power system as claimed in claim 11, wherein the vanes in said first and second pairs are pivotable about a common pivot axis.

13. A hydro-power system as claimed in any one of the preceding claims, wherein each vane is pivotable through 900.

14. A hydro-power system as claimed in any one of the preceding claims further comprising a generator.

A hydro-power system as claimed in claim 14, wherein, in use, said generator is operatively mounted above the surface of the body of water in which the system is installed, or in a watertight casing below the surface of the body of the water in which the system is installed 16. A hydro-power system as claimed in any one of the preceding claims further comprising a hazard beacon.

17. A hydro-power system as claimed in any one of the preceding claims comprising a plurality of endless conveyors.

18. A hydro-power system comprising a plurality of vanes pivotally mounted on an endless conveyor; wherein said vanes are arranged in pairs.

19 A hydro-power system as claimed in claim 18, wherein the vanes in each pair are operatively pivotable between an extended position and a contracted position.

20. A hydro-power system as claimed in claim 18 or claim 19, wherein a first pair of said vanes is provided on a first side of the endless conveyor and a second pair of said vanes is provided on a second side of the endless conveyor.

21. A hydro-power system as claimed in any one of claims 18, 19 or 20, wherein the vanes are arranged in sets, each set consisting of two pairs of said vanes 22. A hydro-power system as claimed in any one of claims 18 to 21, wherein said vanes and the endless conveyor in combination have substantially neutral buoyancy 23 A hydro-power system as claimed in ny one of the preceding claims, wherein said endless conveyor is a chain.

24. A hydra-power system comprising a plurality of vanes pivotally mounted on an endless conveyor; wherein the vanes are arranged in sets and the vanes in each set are distributed uniformly around the endless conveyor.

A hydro-power system comprising a plurality of pivotally mounted vanes, wherein said vanes are buoyant.

26. A hydro-power system substantially as herein described with reference to the accompanying Figures