WO2010055303A2

WO2010055303A2 - Apparatus and method utilising fluids, buoyancy or a combination or part combination of fluids and buoyancy

Info

Publication number: WO2010055303A2
Application number: PCT/GB2009/002661
Authority: WO
Inventors: Warren Leo Gillespie; William Dennis Gillespie; Michael Raymond Gillespie
Original assignee: Warren Leo Gillespie; William Dennis Gillespie; Michael Raymond Gillespie
Priority date: 2008-11-15
Filing date: 2009-11-13
Publication date: 2010-05-20
Also published as: WO2010055303A3; GB0820962D0

Abstract

Apparatus in which objects (9) and/or liquid introduced in to a lower portion of a tower structure (1) containing a column of liquid in which the objects (9) are buoyant. The objects (9) and/or liquid are removed from an upper portion of the tower structure (1) and are returned to the lower portion for re-insertion into the tower structure (1). The objects (9) and/or liquid are returned by a delivery structure (11) including a see-saw device in which a swing arm (45) rocks about a pivot (51) to operate one or more devices (47, 49) that provide or generate a power source.

Description

APPARATUS AND METHOD UTILISING FLUIDS, BUOYANCY OR A COMBINATION OR PART COMBINATION OF FLUIDS AND BUOYANCY.

This invention concerns an apparatus and method utilising fluids, especially liquids, buoyancy or a combination or part combination of fluids and buoyancy. In particular but not exclusively, the apparatus and method can be used to raise liquid only or objects buoyant in a liquid to an elevated position.

A buoyancy system is described in co-pending International patent application No.WO2008/015408 that operates to raise objects in a tower structure using buoyancy of the objects in a liquid contained in the tower structure and then to lower the objects under gravity for return to the tower structure where the raising and/or lowering of the objects can be utilised to provide a power source.

In the system described in my aforementioned application, objects are inserted into the lower end of the tower structure by a ram mechanism. A second tower structure is provided for admitting water to a ram chamber for assisting movement of the ram to transfer the objects from an inlet chamber into the lower end of the main tower structure. The ram chamber is provided with a water displacement mechanism to compensate for the change in volume of the ram chamber as the ram is. displaced to urge the object from the inlet chamber into the main tower structure.

The object rises in the tower structure due to buoyancy in the liquid and is discharged from the upper end of the main tower structure where it picked up by a wheel that rotates under the weight of the object and returns the object to the lower end of the main tower structure where it is re-inserted. Many objects are provided that are inserted into the main tower structure in sequence.

One preferred object of the present invention is to improve the system described in the aforementioned patent application.

Another preferred object of the present invention is to provide additional or alternative power sources utilising buoyancy of the objects.

Yet another preferred object of the present invention is to provide a system based on the addition of liquid as opposed to buoyant objects to the tower structure.

In one aspect of the invention, buoyancy units and/or liquid ejected from the upper end of a tower structure are returned to the tower structure by one or more devices that can be used to provide or generate a power source.

In another aspect of the invention, liquid is admitted to a tower structure in place of or in addition to buoyancy units.

In yet a further aspect of the invention, buoyancy units and/or liquid are admitted to a tower structure at more than one position in the height of the tower structure.

In a still further aspect of the invention, means is employed for transferring buoyancy objects and/or liquid ejected from a tower structure to an inlet device for returning the objects and/or liquid to tower structure. In a preferred embodiment, apparatus according to the invention comprises a tower, a column of liquid contained within the tower, the tower having inlet means at a lower portion of the tower for introducing objects that are buoyant in the liquid and/or liquid into the column of liquid contained in the tower, and outlet means at an upper portion of the tower by means of which objects and/or liquid can be discharged from the tower, the apparatus further comprising delivery means externally of the tower for returning objects discharged from the outlet means of the tower to the inlet means of the tower, the delivery means including at least one see-saw device.

Preferably, said at least one see-saw device comprises a swing arm pivotally mounted at or near its midpoint. Preferably, pivotal movement of the swing arm provides or generates a power source. The power source may be a source of mechanical power or electrical power or any other power source.

Preferably, the swing arm receives objects and/or liquid to one side and then the other side of the midpoint whereby the swing arm rocks about the midpoint and the objects and/or liquid move towards and are released from the ends of the swing arm. Preferably, the see-saw device further comprises a control unit arranged to selectively deliver objects and/or liquid to the swing arm.

Preferably, the delivery means further includes at least one device for lowering objects received from the outlet means to the at least one seesaw device. Preferably the lowering device comprises a wheel or an endless conveyor. Preferably, the tower includes guide means for guiding objects introduced into the tower.

Preferably, the tower includes a storage tank for adding liquid to the tower.

Preferably, the apparatus further includes a second tower and a column of liquid in the second tower. The liquid in the second tower may assist operation of the inlet means. Alternatively or additionally, the liquid in the second tower may assist operation of the delivery means.

Preferably, a plurality of see-saw devices are provided, preferably arranged in parallel and/or series.

According to another preferred embodiment, a method according to the invention comprises the steps of providing a column of liquid, introducing objects buoyant in the liquid and/or liquid into a lower portion of the column of liquid, removing objects and/or liquid from an upper portion of the column of liquid and returning the objects and/or liquid to the lower portion of the column of liquid, wherein the step of returning the objects and/or liquid to the lower portion of the column of liquid is used to provide or generate a power source from gravitational potential energy of the objects and/or liquid by means including at least one see-saw device.

These and other objects of the invention will be apparent from the following description of exemplary embodiments wherein like reference numerals are used throughout to indicate the same or similar parts and in which: Figure 1 is a schematic view showing a buoyancy apparatus according to an embodiment of the invention;

Figure 2 is a schematic view showing one embodiment of the swing arm shown in Figure 1 ; and

Figure 3 is a schematic view showing a buoyancy apparatus according to another embodiment of the invention.

Referring first to Figure 1 of the accompanying drawings, there is shown a first embodiment of apparatus according to the present invention. The apparatus employs a tower structure (1) preferably arranged vertically although it may be arranged at an angle to the vertical. The tower structure (1) contains a column of liquid, typically water.

The tower structure (1) preferably has inlet means towards the lower end and outlet means towards the upper end. In this embodiment, the inlet means preferably comprises first (3) and second (5) inlet devices and the outlet means preferably comprises an outlet device (7) . In other embodiments the number of inlet and outlet devices may vary.

The inlet device (3) is preferably employed to introduce objects (9) into a lower portion of the tower structure (1) that are buoyant in the liquid in the tower structure (1) . The inlet device (5) is preferably employed to introduce liquid, preferably the same liquid as contained in the tower structure (1) , into a lower portion of the tower structure (1) . The inlet devices (3) and (5) may introduce the objects (9) and liquid at substantially the same height or at different heights. The outlet device (7) is preferably employed for transferring objects (9) and liquid from the tower structure (1) to return means that may be used for returning objects (9) and liquid to the inlet devices (3) and (5) respectively or to a storage facility (not shown) . In this embodiment, the return means preferably comprises a delivery structure (11) .

Within the tower structure (1) there is preferably guide means for guiding objects (9) introduced into the tower structure. In this embodiment, the guide means preferably comprises a conveyor system including an endless conveyor belt (13) or chain extending between guide rollers or sprockets (not shown) mounted on rotatable spindles (15, 17) towards the lower and upper ends of the tower structure (1) adjacent to the inlet devices (3, 5) and outlet device (7) . The conveyor belt (13) is preferably provided with a plurality of holders preferably in the form of curved plates (19) extending transversely of the belt (13) and spaced apart, preferably uniformly, along the length of the belt (13) .

The inlet device (3) preferably includes a loading station (21) to receive objects (9) from the delivery structure (11) and a power drive (23) such as a ram for inserting the objects (9) one at a time into the tower structure (1) through a one-way entry arrangement that is preferably self- sealing to prevent or reduce loss of liquid from the tower structure (1) . In this embodiment, the objects are preferably cylindrical although other shapes could be employed and, as each object (9) is inserted, it is located below one of the plates (19) of the conveyor belt (13) .

The upward force of the objects (9) on the plates (19) due to their buoyancy in the liquid in the tower structure (1) causes the belt (13) to move in the direction of arrow X. The objects (9) are preferably retained by the plates (19) until the plates (19) reach the upper end of the conveyor system where the objects (9) are preferably released as the conveyor belt (13) moves around the guide roller at the upper end of the conveyor system. As the objects (9) are released, they can rise clear of the conveyor system and are directed towards the outlet device (7) optionally assisted by a deflector (25) . Movement of the conveyor belt (13) under the buoyancy of the objects (9) retained by the plates (19) causes the guide rollers and in turn the spindles (15, 17) to rotate. Rotation of one or both spindles (15, 17) may be used to operate other equipment or provide or generate a power source. For example, one or both spindles (15, 17) may provide a power take off to assist directly or indirectly operation of other parts of the apparatus . Thus, where provided, a power source or power take-off from one or both spindles (15, 17) may assist operation of one or both inlet devices (3) and (5) .

The inlet device (5) preferably includes a inlet chamber (27) for liquid, a feed chamber (29) for adding liquid to the inlet chamber (27) preferably via a non return valve (30) , and a power drive (31) such as a ram for inserting the liquid into the tower structure (1) through a one-way entry arrangement preferably including one or more non-return valves (33) to prevent return flow of liquid from the tower structure (1) to the inlet chamber (27) . The addition of liquid to the tower structure (1) causes the liquid level to rise and, depending on the arrangement of the conveyor system within the tower structure (1) may assist movement of the conveyor belt (13) .

An optional storage tank (35) is mounted on top of the tower structure (1) . The tank (35) may collect rainwater and/or may be connected to any other convenient source of water such as rivers, dams or the sea. Liquid in the tank (35) may be used to fill and top-up liquid levels in the tower structure (1) when required. The storage tank (35) may be provided with an overflow pipe (not shown) . The outlet device (7) preferably includes a channel section chute (37) that receives objects (9) released from the conveyor system and/or water overflowing from the tower structure (1) when the liquid level in the tower structure (1) is raised to the level of the outlet device (7) . The chute (37) is preferably inclined downwards to direct the objects (9) and/or water towards the delivery structure (11) . The objects (9) and/or water are preferably confined by the sides of the chute (37) and the objects (9) can roll down the chute (37) to the delivery structure (11) .

The delivery structure (11) preferably includes means for lowering objects (9) and/or water received from the outlet device (7) . In this embodiment, the lowering means preferably comprises a wheel (39) mounted on a shaft (41) for rotation. The surface of the wheel (39) is preferably provided with a plurality of channels or chambers (43) configured to receive and retain water transferred to the delivery structure (11) from the tower structure (1) . The wheel (39) is preferably also provided with means (not shown) to receive and retain objects (9) transferred to the delivery structure (11) from the tower structure (1) . As shown, objects (9) and/or water are preferably delivered to the wheel (39) at a position slightly past the mid-centre at the top of the wheel (39) .

The weight of the objects (9) and/or water transferred to the wheel (39) causes the wheel (39) to rotate in the direction of the arrow Y under gravity thereby lowering the objects (9) and/or water. Rotation of the wheel (39) causes the shaft (41) to rotate which may be used to operate other equipment or provide or generate a power source. For example, the shaft (41) may provide a power take off to assist directly or indirectly operation of other parts of the apparatus. The objects (9) and/or water are preferably retained by the wheel (39) as it rotates and are preferably released from the wheel (39) at or approaching the bottom of the wheel (39) .

The delivery structure (11) preferably further includes means for collecting objects (9) and/or water released from the wheel (39) and returning the objects (9) and/or water to the respective inlet devices (3, 5) to be re-inserted into the tower structure (1) . In this embodiment, this means is preferably in the form of a see-saw device employing a swing arm (45) that is preferably pivotally mounted at or towards its mid point and a control unit (55) that is preferably arranged to collect objects (9) and/or liquid released from the wheel (39) .

The control unit (55) is preferably arranged to deliver the objects (9) and/or water to inclined arm sections (57, 59) respectively of the swing arm (45) . The objects (9) and/or water are preferably released to the arm sections (57, 59) alternately by the control unit (55) and cause the swing arm (45) to rock about the centre pivot (51) in the manner of a see-saw between a first end position shown in Figure 1 in which the right hand arm section (57) is lowered and the left hand arm section (59) is raised and a second end position (not shown) in which the left hand arm section (59) is lowered and the right hand arm section (57) is raised. The end positions are determined when the raised arm section contacts the control unit (55) .

In each end position, an object (9) and/or liquid can be released from the end of the arm section that is lowered (the right hand arm section (57) in Figure 1) and an object (9) and/or liquid can be transferred from the control unit (55) to the arm section that is raised (the left hand arm section (59) in Figure 1) . On release of the object (9) and/or liquid from the lowered arm section, the weight of the object (9) and/or liquid transferred to the raised arm section causes the swing arm (45) to pivot about the centre pivot (51) so that the raised arm section is lowered and the lowered arm section is raised. During this movement, the object (9) and/or liquid on the arm section that is being lowered preferably moves to the end of the arm section from where it can be released and the arm section that is being raised preferably comes into contact with the control unit (55) and can receive an object (9) and/or liquid from the control unit (55) to pivot the arm (45) . Objects (9) released from the swing arm (45) are preferably collected and returned to the loading station (21) of the inlet device (3) . Water released from the swing arm (45) is preferably collected by a duct (58) and returned to the feed chamber (29) of the inlet device (5) . The above operation repeats while the control unit (55) receives objects (9) and/or water from the wheel (39) .

The swing arm (45) preferably rocks up and down in this way to alternately direct objects (9) and/or water to opposite ends of the swing arm (45) . The see-saw motion of the swing arm (45) is preferably employed to actuate one or more devices (47, 49) arranged below the swing arm (45) , preferably either side of the centre pivot (51) , so that the devices (47, 49) are operated alternately as the swing arm (45) rocks about the centre pivot (51) . The devices (47, 49) may comprise hydraulic, mechanical, pneumatic or electrical rams.

Means (53) may be provided to supply objects (9) and/or water to the swing arm (45) from any suitable source if required to assist operation.

For example objects (9) and/or water may be supplied to the swing arm (45) when starting the apparatus to position the swing arm (45) in an end position ready to receive an object (9) and/or water from the control unit (55) . The water is preferably returned to the tower structure (1) by means of the inlet device (5) . However, we may also divert some water to the inlet device (3) for return to the tower structure with the objects (9) . This may be desirable if the volume of water exceeds the capacity of the inlet device (5) to minimise water loss from the system.

Operation of the devices (47, 49) can be used to operate other equipment or to provide or generate a power source. The power source may be mechanical, electrical or any other suitable power source. For example, one or both devices (47, 49) may operate or assist operation of other parts of the apparatus. Thus, device (49) is shown assisting operation of the power drive (23) for inserting objects (9) into the tower structure (1) and device (47) is shown assisting operation of the power drive (31) for inserting water into the tower structure (1) and the conveyor system in the tower structure. Other uses of the devices (47, 49) are envisaged and will be understood by those skilled in the art. Spindle (15) is also shown assisting operation of the power drive (31) .

Referring now to Figure 2, one embodiment of a see-saw device is shown in more detail and like reference numerals are used to indicate parts corresponding to Figure 1. The see-saw device includes control unit (55) arranged to transfer objects (9) and/or water from the wheel (39) to the swing arm (45) for return to the inlet devices (not shown in Figure 2) and insertion into the tower structure (not shown in Figure 2) .

The swing arm (45) is preferably pivotally mounted at or towards its mid- point so as to tip up and down as indicated by the arrows A in the manner of a see-saw. The control unit (55) is preferably arranged to receive objects (9) and/or water from the wheel (39) and deliver the objects (9) and/or water to inclined arm sections (57, 59) respectively of the swing arm (45) . The objects (9) and/or water are preferably released to the arm sections (57, 59) alternately by the control unit (55) and move towards the ends of the swing arm (45) to cause the swing arm (45) to rock about the centre pivot (51) in the manner of a see-saw. Release mechanisms (61, 63) at the ends of the swing arm (45) preferably release the objects (9) and/or water from the swing arm (45) for return to the inlet devices of the tower structure. As described previously, the swing arm (45) rocks between end positions such that when one arm section is lowered to release objects (9) and/or water, the other arm section is raised to receive objects (9) and/or water from the control unit (55) . The operation of this device will be understood from the description of Figure 1.

Referring now to Figure 3, there is shown a second embodiment of apparatus according to the invention in which like reference numerals are used to indicate parts corresponding to Figures 1 and 2. The arrangement and operation of corresponding parts will be understood from the description of Figures 1 and 2.

In this embodiment, the inlet device (5) for adding water to the tower structure (1) is preferably provided at a higher point of the tower structure (1) than the inlet device (3) for adding objects (9) to the tower structure. This is not essential and both inlet devices (3, 5) could be at the same height. A pump (65) may be provided for the water supply to top up the storage tank (35) . The pump (65) may be driven directly by a power take off from one or both spindles (15, 17) or shaft (41) or indirectly by an electric motor powered by a generator driven by a power take off from one or both spindles (15, 17) or shaft (41) . Any other means of operating the pump (65) may be employed.

A second tower structure (67) is preferably provided containing liquid, typically water as provided in the tower structure (1), and a feed pipe (69) preferably connects the tower structures (1 , 67) for transferring water from the first tower structure (1) to the second tower structure (67) . A storage tank (71) for liquid contained in the second tower structure (67) is preferably mounted on top of the second tower structure (67) . The storage tank (71) may collect rainwater and/or may be connected to any other convenient source of water such as rivers, dams or the sea. A pump (73) may be provided for the water supply to top up the storage tank (71) . The pump (73) may be driven directly by a power take off from one or both spindles (15, 17) or shaft (41) or indirectly by an electric motor powered by a generator driven by a power take off from one or both spindles (15, 17) or shaft (41) . Any other means of operating the pump (73) may be employed. The storage tank (71) may be provided with an overflow pipe (not shown) . Water in the tank (71) may be used to fill and top-up liquid levels in the tower structure (67) via a valve (not shown) operated by a float (75) when required.

The water in the second tower structure (67) may be used to assist operation of the apparatus. As described previously, the power drive (31) of the inlet device (5) for adding water to the tower structure (1) may include a ram that may be assisted in its operation by the swing arm (45) . The ram may also be assisted by the output from one or both spindles (15, 17) of the conveyor system or shaft (41) or indirectly by an electric motor powered by a generator driven by a power take off from one or both spindles (15, 17) or shaft (41) . Alternatively or additionally, the power drive (31) may be connected to the second tower structure (67) by one or more valves (77) by means of which pressure of water in the second tower structure (67) can be used to counteract the pressure of water in the first tower structure (1) when adding water to the first tower structure (1) such that the power requirements to operate the ram may be reduced. A line (not shown) may also allow water to be diverted from the tower structure (67) to the feed chamber (29) .

Also in this embodiment, the inlet device (3) may be supported by the tower structure (67) . A power take off from spindle (15) may assist operation of the ram for the power drive (23) for the inlet device (3) . In a modification (not shown) , water in the tower structure (67) may be used to assist operation of the ram for the power drive (23) when introducing objects (9) into the tower structure (1) .

Alternatively or additionally, the water in the second tower structure may be employed to start and stop rotation of the wheel (39) and/or to control the rotational speed of the wheel (39) . Thus, one or more valves (79) may control supply of water from the second tower structure to one or other side of the wheel (39) start or stop rotate of the wheel (39) and/or to increase or reduce the speed of rotation. For example, adding water to the right hand side of the wheel (39) as viewed in Figure 3 may be used to start rotation of the wheel (39) and/or in use will add to the weight of objects (9) and/or water transferred from the tower structure (1) to increase the speed of rotation while adding water to the left hand side will have the opposite effect and may be used to stop rotation of the wheel (39) and/or to reduce the speed of rotation of the wheel (39) .

In this embodiment, swing arm (45') preferably receives objects (9) and water from the wheel (39) via control unit (55') . Water released from the swing arm (45') is returned to feed chamber (29) for the inlet chamber (27) of the inlet device (5) for return to the tower structure (1) .

As shown, one end of the swing arm (45') preferably delivers water to a duct (81) connected to the feed chamber (29) . The other end of the swing arm (45') may deliver water directly to the feed chamber (29) or to the duct (81) for return to the feed chamber. The devices (47' , 49') actuated by the see-saw motion of the swing arm (45') preferably assist operation of the inlet device (5)

Objects (9) released by the swing arm (45') are preferably collected and transferred to the control unit (55") . Swing arm (45") preferably receives the objects (9) from the control unit (55") and preferably transfers the objects (9) to a line (not shown) feeding the loading station (21) of the inlet device (3) for return to the tower structure (1) . In this embodiment, the control unit (55") preferably also receives water that has been used to assist operation of the ram of the power drive for the inlet device (5) and delivers the water to the swing arm (45") . As shown, water in the tower structure (67) is preferably admitted to a ram chamber (83) to assist forward movement of the ram of the inlet device (5) to insert water into the tower structure (1) . The water is transferred to the control unit (55") via a non-return valve (85) and a line (87) in the forward position of the ram to drain the ram chamber (83) and allow return movement of the ram. As shown, a duct (89) preferably collects water released from the swing arm (45") and preferably transfers the water to a chamber (91) that supplies the water via one or more nonreturn valves (93) to the inlet device (3) to assist insertion of the objects (9) into the tower structure (1) . As shown, the ends of the objects 9) are preferably concave or recessed so that adjacent ends of successive objects (9) can provide an area to receive the water for return to the tower structure (1) with the objects (9) without any significant adverse effect on the insertion of the objects (9) . In this way, water loss from the apparatus may be minimised. The devices (47" , 49") actuated by the see-saw motion of the swing arm (45") preferably assist operation of the inlet device (3) . Means (95) is preferably provided that can be selectively employed to collect and direct objects (9) and water from the wheel (39) to a storage facility (not shown) if required. For example, if the apparatus is not in use or needs to be stopped for any reasons such as to allow repairs or maintenance, the objects (9) and water can be diverted to the storage facility until the apparatus is to be re-started. When re-starting the apparatus, objects (9) and/or water may be supplied directly from the storage facility to the inlet devices (3) and (5) . Alternatively or additionally, objects (9) and/or water may be supplied to the see-saw devices for return to the inlet devices (3) and (5) . In other respects, the operation of this embodiment will be understood from the description of Figures 1 and 2.

In the above-described embodiments, the tower structure (1) preferably has an inlet device (3) for introducing objects (9) that are buoyant in the liquid in the tower structure (1) and another inlet device (5) for introducing liquid. It is not essential to introduce both objects (9) and liquid to the tower structure (1) and some embodiments of the apparatus may introduce objects only while other may introduce liquid only with appropriate modifications to other parts of the apparatus as necessary. Where separate inlet devices (3, 5) are provided for adding objects (9) and water, these may be provided at the same height position in the tower structure (1) as shown in Figure 1 or at different height positions as shown in Figure 3. More than one inlet device (3) may be provided for adding objects (9) to the tower structure (1) and may be provided at the same height position in the tower structure (1) or at different height positions. More than one inlet device (5) may be provided for adding liquid to the tower structure (1) and may be provided at the same height position in the tower structure (1) or at different height positions. Any number of inlet devices (3) for objects (9) and any number of inlet devices (5) for liquid may be provided at the same or different heights and one type of inlet device may be provided independently of the other type or both types may be provided in any combination.

In the above described embodiments, the tower structure (1) preferably has a conveyor system that extends from the lower end to the upper end. It is not essential to employ a conveyor system and the apparatus may be employed without a conveyor system in the tower structure (1) . Where provided the conveyor system may comprise a single unit as shown in Figures 1 and 3. Alternatively, more than one unit may be provided. Multiple units increases the number of potential outputs for assisting operation of other parts of the apparatus and or for providing or generating a power source. Where two or more units are provided, these may be arranged one above the other so that objects are transferred from one unit to the next as they rise up the tower structure. Multiple units on top of each other may be particularly useful in very tall tower structures where a single unit may not be practical and/or may not be as efficient as multiple units. Alternatively multiple units may be arranged side by side. Where units are arranged side by side these may be fed by the same inlet device or separate inlet devices and the units may be the same height or different heights. The conveyor system separates the objects as the rise in the tower structure and/or controls the ascent of the objects. This is beneficial as it avoids the objects interfering with each other and potentially blocking the tower structure. It also allows the transfer of objects from the tower structure to the delivery structure to be achieved in a controlled manner by releasing the objects one at a time, again reducing the risk of interference between the objects. Any other means for achieving one or both of these benefits may be employed in place of the conveyor system. In the above described embodiments, the delivery structure preferably includes a wheel to collect and lower objects and/or water discharged from the tower structure. Rather than one large wheel, it may be desirable to employ two or more smaller wheels and to transfer the objects and/or water between the wheels as they are being lowered. This may be particularly beneficial if the tower structure is very tall and one large wheel of the appropriate size may not be practical and/or efficient. It is not essential to employ one or more wheels to lower the objects and/or water. For example a conveyor system may be used with appropriate means to retain objects and/or water received from the tower structure at an elevated position and to release the objects and/or water at a lowered position. The conveyor system may comprise a single unit or multiple units arranged one above the other to transfer the objects and/or water from one unit to another as they are being lowered. Employing a conveyor system may increase the number of potential outputs for assisting operation of other parts of the apparatus and or for providing or generating a power source. Multiple units may be particularly useful where the tower structure is very tall and a single unit may not be practical and/or may not be as efficient as multiple units. It is also envisaged that we may employ a combination of one or more wheels with one or more conveyor units to lower the objects and/or water.

In the above-described embodiments, one wheel and/or conveyor is preferably used to lower both objects and water. In a modification, the device for transferring objects and/or water from the tower structure to the delivery structure may be arranged and adapted to separate the objects and water and the delivery structure may comprise separate wheels and/or conveyors for lowering the objects and water. Also in the above- described embodiments, the wheel and/or conveyor receive objects and/or water from one tower structure. In a modification, more than one tower structure may be provided in which objects (9) and/or liquid are raised to an elevated position and the wheel may receive objects and/or liquid from more than one tower structure. The objects and/or liquid from the tower structures may be separated and delivered to different wheels and/or conveyors. Where provided, the wheel (s) and/or conveyor(s) may be replaced by any other suitable means for lowering the objects and/or liquid.

In the above-described embodiments, one or more see-saw devices may be used to assist operation of other parts of the apparatus and/or to provide or generate a power source. Where more than one see-saw device is employed, these may be arranged in parallel or series thereby increasing the number of potential outputs for assisting operation of other parts of the apparatus and/or for providing or generating a power source. The see-saw device is a particularly effective means of making use of the objects and/or water to assist operation of other parts of the apparatus and/or for providing or generating a power source. The see-saw device does not have to be as tall as the wheel and can have a length less than, equal to or greater than the width of the wheel so as to make effective use of the available space for incorporation in the apparatus.

In the above-described embodiments, the see saw device comprises an arm that rocks about a pivot point at or towards the mid-point of the arm as objects and/or liquid are transferred to the arm either side of the pivot point. The up and down movement of the arm can be used to provide or generate a power source as described by means of appropriate devices arranged to be actuated by the up and down movement. The number and arrangement of the devices may be altered from that shown and described. It will also be understood that other arrangements for achieving an up and down movement under the action of objects and/or water may be employed for the same purpose and the term see-saw device is intended to include such devices.

Where provided, rotation of the wheels or belts may be enhanced by the use of means employing other available sources of natural power. For example the wheels or drive belt sprockets maybe provided with formations such as vanes to make use of wind power to assist rotation and increase torque. We may employ air tunnels to channel the wind to improve efficiency.

Although the invention has been described for applications for driving a power source such as a wheel or belt, the invention is not limited to such application and raising buoyancy units or fluid in the tower structure may be used for other purposes. For example, to pressurise a liquid system like a conventional water tower once the liquid has reached its upper level.

The above described apparatus may be combined with other systems for generating power or energy such as solar power systems. For example, solar panels may be mounted on the tower structure.

The various feed lines may be combined where an improvement in efficiency may be obtained.

As will be understood from the description of the exemplary embodiments, the invention provides a system in which objects and/or liquid that are raised from a starting point to a desired height are returned to the starting point by one or more devices that may provide or generate a power source utilising energy that may be extracted from the apparatus by means of gravity. More especially, the mass (weight) of the objects and/or liquid is utilised as the objects are lowered from the desired height under gravity to operate the one or more devices to extract energy allowing the one or more devices to provide or generate a power source. By providing more than one device and transferring the objects and/or liquid between the devices as they are being lowered for return to the starting point, effective and efficient use of the objects and/or liquid can be made to optimise the energy produced by lowering the objects and/or liquid.

Features of any of the embodiments may be employed separately or in combination with features of any other embodiments. The see-saw device may be used in any other apparatus where objects and/or liquid raised in a tower structure are collected and returned to the tower structure. For example we may employ the see saw device in the apparatus described in co-pending International patent application No.WO2008/015408.

Other modifications and improvements will be apparent to those skilled in the art.

Claims

1. Apparatus comprising a tower, a column of liquid contained within the tower, the tower having inlet means at a lower portion of the tower for introducing objects that are buoyant in the liquid and/or liquid into the column of liquid contained in the tower, and outlet means at an upper portion of the tower by means of which objects and/or liquid can be discharged from the tower, the apparatus further comprising delivery means externally of the tower for returning objects discharged from the outlet means of the tower to the inlet means of the tower, the delivery means including at least one see-saw device.

2. Apparatus according to claim 1 wherein said at least one see-saw device comprises a swing arm pivotally mounted at or near its midpoint.

3. Apparatus according to claim 2 wherein pivotal movement of the swing arm provides or generates a power source.

4. Apparatus according to claim 2 or claim 3 wherein the swing arm receives objects and/or liquid to one side and then the other side of the midpoint whereby the swing arm rocks about the midpoint and the objects and/or liquid move towards and are released from the ends of the swing arm.

5. Apparatus according to claim 4 wherein the see-saw device comprises a control unit arranged to selectively deliver objects and/or liquid to the swing arm.

6. Apparatus according to any preceding claim wherein the delivery means further includes at least one device for lowering objects received from the outlet means to the at least one see-saw device.

7. Apparatus according to claim 6 wherein the lowering device comprises a wheel or an endless conveyor.

8. Apparatus according to any preceding claim wherein the tower includes guide means for guiding objects introduced into the tower.

9. Apparatus according to any preceding claim wherein the tower includes a storage tank for adding liquid to the tower.

10. Apparatus according to any preceding claim wherein the apparatus further includes a second tower and a column of liquid in the second tower.

11. Apparatus according to claim 10 wherein liquid in the second tower assists operation of the inlet means.

12. Apparatus according to claim 10 or claim 11 wherein liquid in the second tower assists operation of the delivery means.

13. Apparatus according to any preceding claim wherein a plurality of see-saw devices are provided.

14. Apparatus according to claim 14 wherein the see-saw devices are arranged in parallel and/or series.

15. A method comprising the steps of providing a column of liquid, introducing objects buoyant in the liquid and/or liquid into a lower portion of the column of liquid, removing objects and/or liquid from an upper portion of the column of liquid and returning the objects and/or liquid to the lower portion of the column of liquid, wherein the step of returning the objects and/or liquid to the lower portion of the column of liquid is used to provide or generate a power source from gravitational potential energy of the objects and/or liquid by means including at least one see-saw device.