GB2224807A - Electricity generating system - Google Patents

Abstract

An arrangement for generating electricity in mountainous terrain, especially where there is no regular heavy rain fall, comprises filling with water from a catchment area (20) one of a pair of linked containers (18a, b: 18c, d) at a first location on an upland site, allowing the first, full, container (18a) to move under the force of gravity from the first location to a second, lower, location whilst pulling the second, empty container (18b) from the second location up to the first location. The containers are pulled by cables (22a, b) which engage pulley wheels, (14a, b) rotation of which may be used to operate a dynamo arrangement (26). <IMAGE>

Description

ELECTRICITY GENERATING SYSTEM The present invention relates to an electricity generating system and particularly to an electricity generating system for use in terrain including mountains and hills.

It is the object of the present invention to provide an electricity generating system and a method of generating electricity particularly but not exclusively for use in locations where, because of small amounts of precipitation or water catchments available, a conventional hydro-electric generating system would not be practical.

According to a first aspect thereof, the present invention provides an electricity generating system comprising at least one pair of containers each of which is adapted to be filled with and emptied of water in and alternating sequence and which are movable under the force of gravity between a first location in mountainous terrain and a second, lower, location, filling means disposed at said first location for filling an empty container with water, emptying means disposed at said second location for emptying a filled container of water, at least two guide tracks disposed between said first and second locations, the tracks being of uniform slope and each container being movable along a respective track between the first and second locations, linking means operating between the containers of each pair so that as one full container descends from the first location to the second location the other container ascends in an empty condition from the second location to the first location, and energy conversion means coupled to said linking means whereby the energy produced by the motion of a descending, filled, container is converted to electrical energy.

Preferably, said filling means may be provided by a water tank filled from a water catchment area on said mountain, the water tank having a closeable opening through which water may be supplied to said container.

Preferably, the emptying means may be provided by a door of the container which may be opened when the full container reaches the second location to allow water to flow into a water spillway disposed at said second location.

In a preferred example, the linking means comprise a cable coupled between said containers, said cable being disposed around a pulley wheel located at said first location.

Advantageously, the energy conversion means may comprise first and second energy conversion devices, the first conversion device adapted to convert the linear motion of the full container into rotary motion, and the second conversion device adapted to convert the rotary motion into electrical energy.

Preferably, the first energy conversion device is provided by the cable and pulley wheel, the movement of the cable in response to the linear movement of a full container causing said pulley wheel to rotate.

Preferably, the second energy conversion device may be provided by a dynamo coupled to the pulley wheel.

Conveniently said pulley wheel is coupled to the dynamo by a shaft and high ratio gearing.

In the preferred example, there are provided at least two pairs of containers, each container being mounted on a respective guide track, said pairs of containers being arranged such that there is at least one container which is full and which is descending from said first location to said second location at all operating times.

Conveniently, there is provided a container release mechanism to ensure that as an ascending empty container of one pair of containers reaches said first location, a full container of the other pair is released from said first location to descend to said second location.

Preferably, there may be provided a pulley wheel and cable for each pair of containers. Both the pulley wheels may be coupled to the dynamo or, alternatively, each of the pulley wheels are coupled to respective dynamos.

Conveniently, each of said containers may be mounted on slides or running wheels which allow the containers to travel along their respective rail tracks.

According to the nature of the terrain, the rail tracks may be disposed within a tunnel linking said first and second locations, or each of the rail tracks may be disposed in a separate tunnel. Where the terrain permits, the rail tracks may be disposed in an open arrangement on the slope of the mountain.

According to a second aspect of the present invention, there is provided a method of generating electricity comprising the steps of: filling with water one of a pair of linked containers at a first location on a mountain or upland terrain; allowing the full container to move, under the force of gravity from said first location to a second, lower, location whilst pulling the second, empty, container from said second location to said first location, and causing electricity to be generated in response to the movement of said containers.

In a preferred arrangement an electricity generating station is situated at a first location in mountainous terrain and a water spillway terminal is disposed at a second, lower, location. The station and terminal are linked by four tunnels, or series of tunnels, each tunnel having a rail track of constant slope disposed therein. A container which may be filled with water is disposed in each tunnel. Each container is mounted on a respective rail track and is movable under the force of gravity between the station and the terminal. Each container is adapted for filling with water in a filling bay of the station and for travel down a tunnel under the force of gravity.

The linear movement of the container between the locations is converted into electrical energy by energy conversion apparatus disposed in the generating station. As each full container descends from the generating station to the terminal, an empty container is pulled from the terminal to the station. There should always be one full container descending from station to terminal to ensure uniform power generation in the system. Each full container empties its load of water upon entering the terminal and re-ascends in an empty condition.

There now follows a detailed description of an example of an arrangement according to the invention.

It will be understood that the description is given by way of example only and not by way of limitation.

Fig. 1 is a diagrammatic sectional view of part of an electricity generating system in accordance with the present invention; Fig. 2 is also a diagrammatic sectional view of part of the electricity generating system shown in Fig. 1, but shown from a different angle; Fig. 3 is an elevational view of a water container for use in the system shown in Figs. 1 and 2; Fig. 4 is a plan view of the water container shown in Fig. 3; Figs. 5A and 5B are diagrammatic views of a water container filling mechanism used in the system shown in Figs. 1 and 2, and Figs. 6A and 6B show a pulley arrangement which may be used as an alternative to that used in the system shown in Figs. 1 and 2, Fig. 6B being a view in the direction of arrow A of Figure 6A.

Reference is first made to Figs. 1 and 2 of the drawings which show an electricity generating system, generally indicated by reference numeral 10. The system 10 comprises an electricity generating station 12 located as high as possible in a mountainous area, and a water spillway terminal 14 located further down the mountain. The station 12 and terminal 14 are linked by four tunnels 16a,16b,16c and 16d, each tunnel 16a-16d having a rail track 17 disposed therein upon which wheeled water containers 18a-d (best shown in Figs. 3 and 4) can travel along tunnels 16a-d respectively.

The water containers 18a,18b, 18c and 18d are each alternately filled with water supplied from a water catchment area 20 as will be described and travel down tunnels 16a-d respectively, the downward movement of each container 18a-d causing electricity to be generated in a manner which will also be described.

Water container 18a is coupled to water container 18b by a cable 22a as best shown in Fig. 2. Cable 22a extends along tunnels 16a and 16b and is disposed around pulley wheel 24a. When water container 18b is filled with water, the force of gravity acts on the mass of container 18b causing it to travel down tunnel 16b whilst pulling cable 22a behind it. The pulling of cable 22a causes container 18a simultaneously to ascend the tunnel 16a acting as a back balance to container 18b. The cable 22a passes around pulley wheel 24a, which is caused to rotate. The pulley wheel 24a is coupled to a dynamo 26 through a high ratio gear system 28. As the pulley wheel 24a rotates due to the movement of the cable 22a, the rotation is transmitted to the input shaft of the dynamo 26 and thus electricity is generated as will be described later.Water containers 18c and 18d are coupled together in a similar manner to containers 18a and 18b by cable 22b which is disposed around pulley wheel 24b. The function of each of these components is substantially the same as that described above.

Generating station 12 comprises a filling bay 30 in which water containers 18a-d are each filled in turn with water supplied from catchment area 20. Water is supplied to containers 18a-d through an opening 32 of a header tank arrangement 34. The header tank arrangement 34 comprises two tanks 34a and 34b which are connected to the catchment area 20 by pipes 36a and 36b respectively. Both tanks 34a and 34b have capacities approximately equal to that' of each water container 18a-d. When a water container 18 is in the position shown in broken outline in Fig. 1, the container 18 is filled with water supplied from the header tank 34.

When container 18 is filled with water it is substantially heavier than when empty, thus the container 18 may descend track 17 pulling up an empty container in the manner described above.

Spillway terminal 14, located at a lower location on the mountain, comprises a guarded culvert spillway 37 which links the terminal 14 with a lake 38. When a container 18 descends the tunnel 16 and arrives at terminal 14, the water inside the container 18 is released to flow through spillway 37 and into lake 38 as will be described later in detail. As container 18 travels at a substantial speed the container 18 must be slowed almost to a stop before entering terminal 14.

Drag brakes 40a-d are disposed in tunnels 16a-d respectively and are used to slow the containers 18.

Drag brakes 40a-d, similar to those used on aircraft carriers to bring aircraft to a halt, decelerate the descending container 18 to such a speed that the descending container 18 may be stopped in terminal 14 when the container 18 reaches hydraulic buffers 42.

Because of the period of time taken to fill an empty container 18 in station 12 and empty a full container in terminal 14, there may be a short period of time when no electricity is being generated by movement of the pair of containers 18a and 18b. To overcome this problem it is ensured that there is always at least one container 18 descending a tunnel at a uniform velocity, to ensure uniform generation of electricity. As an empty container, for example container 18c, ascends the tunnel 16c the empty container 18c triggers a mechanical release switch 42c (best shown in Fig. 2) which causes a full container, for example container 18b, to commence its descent of tunnel 16b. The full container 18b is held in position in station 12 by a hydraulic lock 44 shown in Fig. 3.When the release switch 42c is triggered by the ascending container 18c, lock 44 is released to allow the full container 18b to commence descent of the tunnel 16b. Release switch 42 is placed at a distance from station 12, this allows the descending full container 18b to gain a desired optimum speed before the empty container 18c reaches and stops in station 12.

A descending container 18 travels at a predetermined optimum speed for electrical generation. A speed control mechanism (not shown) is coupled to the drive wheels 24a and 24b to ensure that the drive wheels 24a,24b rotate at the optimum speed and that the container 18 which is descending travels at a corresponding optimum speed.

Reference is now made to Figs. 3 to 5B of the drawings, Figs. 3 and 4 being elevational and plan views respectively of a container 18 in the locked position in station 12, and Figs. 5A and 5B being diagrammatic views of a water container filling mechanism. The container 18 is generally rectangular in shape and is mounted upon wheels 50 which allow container 18 to travel along track 17. The container 18 has a baffled inlet 52 through which the container 18 may be filled with water, and a hinged outlet door 54 which may be opened to let the water flow out of container 18 under the force of its own weight. Header tank 34 has an opening 32 over which is disposed a hinged blanking plate 56 to prevent the water flowing prematurely from opening 32 as shown in Fig. 5A.The blanking plate 56 is coupled to a lever 58 which allows the plate 56 to be moved to allow water to flow through opening 32. When a container 18 is in the position shown in broken outline in Fig. 1, the lever 58 and plate 56 are moved to the position shown in Fig. 5B and water in header tank 34 flows into container 18 to fill the container 18.

As hereinbefore described, tanks 34a and 34b each have approximately the same capacity as one of the containers 18. This allows a container 18 to be filled relatively quickly without metering. The volumes of water in tanks 34a and 34b are controlled by ball cock mechanisms 60a and 60b respectively, when the tanks 34a or 34b are filled with the correct volume of water, the ball cock mechanisms 60a or 60b cause a valve to be closed to prevent more water entering the tanks 34a or 34b from catchment area 20.

When each full container 18 enters terminal 14 the water is flushed out of the container 18 as hereinbefore described. The hinged door 54 of container 18 is operated by a mechanical trigger switch 62 (best shown in Fig. 2) as the container 18 enters terminal 14. This causes the hinged door 54 to open which results in the water in container 18 flowing out through the front of the container 18, through spillway 37 and into lake 38.

As a container 18 descends the slope in a tunnel 16, its effective weight increases the further it travels down tunnel 16 due to the additional weight of cable which is added as the distance from station 12 increases. To compensate for this, a trailing cable 75 (best seen in Fig. 2) and equal in length to the drive cable would be coupled to the lower end of each pair of containers, and by travelling round pulleys 76, in the terminal building, would compensate for the changing weight of the drive cables and nullify the imbalance.

The use of containers of equal tare weights would avoid one source of imbalance, leaving the container content load as the true and effective gravitation power source.

Manhole openings 64 are provided in tunnel 16 to facilitate track, channel or cable maintenance.

Pulley wheels 24a and 24b have large diameters giving substantial leverage to drive shaft 25. This enables the high ratio gearing 28 to permit high rotational speed of drive shaft of dynamo 26. The cable 22a is applied to the pulley wheels 24a via pulleys 66.

Pulleys 66 are located as close to each other as possible to provide a maximum amount of cable contact on the circumference of pulley wheels 24a. A similar arrangement is provided for pulley wheel 24b. By using a large diameter pulley wheel 24 with maximum circumferential cable contact, the 'pull' of cable on the pulley wheel is minimised and the slope of the tunnel 16 may be made more shallow, giving longer 'runs' with less bearing wear. In addition, the pulleys 66 and pulley wheels 24 are disposed horizontally to the floor of the station 12 (as best shown in Fig. 1) to minimise friction between the cable 22 and the floor of the station 12. The pulley wheels 24a and 24b are coupled to the same dynamo 26 and gearing arrangement 28 through a centrifugal clutch 68 coupled to the gearing 28.This ensures that dynamo 26 is constantly driven by one or other of the pulley wheels 24a and 24b. A small standby generator 70 (Fig. 2) is provided to initiate the sequence of container descents.

Reference is now made to Figs. 6A and B of the drawings which show an alternative pulley arrangement for applying cable 22 to pulley wheel 24. The pulley wheel 24 is oriented vertically and pulleys 71, 72 and 74 direct the cable in the appropriate directions to provide the required torque to drive shaft 25.

Various modifications can be made to the embodiments hereinbefore described without departing from the scope of the invention. The tunnels may be of any suitable length and possibly up to 20 miles long. The tunnels may be replaced by guarded tracks along which the wheeled containers may run. The system may be used not only in mountainous terrain but may be adapted to make use of small 'runs' on relatively low hills. The spillway may open out into a lake, river, stream, loch, reservoir or the sea. The guarded culvert may be replaced by a system of pipes. The mechanical release switch which causes a container to commence its descent may be replaced by an electronic release switch. The two pulley wheels may be coupled to respective dynamos, the two dynamos being linked in an electrical grid.

Where larger water catchment areas are available a larger number of tunnels could be disposed side by side or one above the other giving a larger generating potential.

Where the terrain only allows short runs, several runs may be arranged in series using the same water which is flushed from one system into the catchment area of another system. This allows the system to be arranged in a zig-zag down the mountain or hillside to maximise use of the terrain. The system is designed to traverse the natural slope of the terrain to reduce the angle of the run and maximise the distance from generating station to spillway terminal. The container size and weight is designed to suit the angle of the run and to maintain optimum cable pressure on the drive wheel. A Ward-Leonard braking system may be incorporated in the system to maintain the optimum speed of travel of container.

A preferred arrangement of the system may incorporate a large diameter pulley wheel, a high gear ratio to the dynamo and a gentle slope for the rail track. Such an arrangement would provide an exceptionally long run for one container and allow a very slow container speed as slow as walking pace with a large container.

Advantages associated with the present invention include an electricity generating system which can operate from a minimal constant water supply.

It is visualised that a container with 10-20 tonnes of water could produce power for as long as the terrain would allow the the maximum length of track - upwards of one hour.

As can be seen, there is a very great saving of water compared with a conventional hydro-electricity station and the volume of water required by the system is so relatively small that a vast number of small hill and mountain lakes and streams could be used to supplement the existing power supplies with no pollution hazards whatever.

Claims (15)

CLAIMS:

1. An electricity generating system comprising at least one pair of containers each of which is adapted to be filled with and emptied of water in and alternating sequence and which are movable under the force of gravity between a first location in mountainous terrain and a second, lower, location, filling means disposed at said first location for filling an empty container with water, emptying means disposed at said second location for emptying a filled container of water, at least two guide tracks disposed between said first and second locations, the tracks being of uniform slope and each container being movable along a respective track between the first and second locations, linking means operating between the containers of each pair so that as one full container descends from the first location to the second location the other container ascends in an empty condition from the second location to the first location, and energy conversion means coupled to said linking means whereby the energy produced by the motion of a descending, filled, container is converted to electrical energy.

2. A generating system as claimed in claim 1, wherein the filling means comprises a water tank supplied from a water catchment area, said tank having a closeable orifice through which water passes to said container, said tank having substantially the same volume capacity as each associated container.

3. A generating system as claimed in either one of claims 1 and 2, wherein the emptying means comprises a closure panel of an opening at a lower portion of the container, and a spillway at the second location adapted to receive water leaving the container through the opening.

4. A generating system as claimed in any one of the preceding claims, wherein the energy conversion means comprises first and second energy conversion devices, a first conversion device being adapted to convert linear motion into rotary motion and the second adapted to convert the rotary motion in an electricity generator.

5. A generating system as claimed in claim 4, wherein the first conversion device comprises said linking means in the form of cables secured to the containers, each of said cables passing around a pulley device at said first location so as to rotate said pulley device.

6. A generating system as claimed in either one of claims 4 and 5, wherein the second conversion device comprises a dynamo arrangement.

7. A generating system as claimed in any one of the preceding claims, wherein there are provided at least two pairs of containers, each container being mounted on a respective guide track, said pairs of containers being arranged such that there is at least one container which is full and which is descending from said first location to said second location at all operating times.

8. A generating system as claimed in claim 7, wherein there is provided a container release mechanism to ensure that as an ascending empty container of one pair of containers reaches said first location, a full container of the other pair is released from said first location to descend to said second location.

9. A generating system as claimed in either one of claims 7 and 8, wherein there are provided two operative pulley wheels and cables, one of which wheel and cable is used for one pair of containers.

10. A generating system as claimed in claim 9, wherein both or all pulley wheels are coupled to a single dynamo.

11. A generating system as claimed in claim 9, wherein each pulley wheel is coupled to a separate dynamo.

12. A generating system as claimed in any one of the preceding claims, wherein said containers are mounted upon slides or upon wheels which enables the containers to travel along the respective rail tracks.

13. A method of generating electricity comprising the steps of: filling with water one of a pair of linked containers at a first location on a mountain or upland terrain; allowing the full container to move, under the force of gravity from said first location to a second, lower, location whilst pulling the second, empty, container from said second location to said first location, and causing electricity to be generated in response to the movement of said containers.

14. An electricity generating system constructed, arranged and adapted to operate substantially as hereinbefore described with reference to and as shown in the drawings.

15. A method of generating electricity substantially as hereinbefore described with reference to the drawings.