The present invention relates to an apparatus for generating rotational movement of a shaft employing the motion of gases rising through liquids in a helical pipe array to generate rotational mechanical energy.

Background of the Invention

It is well known that when introducing gases into certain liquids, the gaseous component freely rises through the liquid and, when harnessed in a balloon or other appropriate container, can be employed to generate lift; for example in the case of air balloons being employed in water to raise objects from the sea bed. In addition, within toys and certain power generation apparatus, air bubbles in water have been used to turn under water wheels which contain air capturing recesses on their outer circumferences. Alternatively, the rising gas moves a bucket conveyor belt type apparatus, where the air is captured within individual containers held on a chain, belt or other means, which then delivers the motion of the rising gas to a cog or wheel. Where such designs are employed to generate meaningful energy which is put to work, they suffer either from a lack of efficiency, or the need for multiple moving parts and numerous components, with the resultant regular maintenance required for such parts, particularly when operating in a submerged environment. This, in turn, leads to higher costs to produce robust

components, higher assembly costs to construct the machines, and reliability issues unless a strict maintenance regime is observed.

It is an aim of the present invention to provide an apparatus which mitigates or obviates at least one of the disadvantages of known devices.

It is an aim of the invention to provide an apparatus for generating rotational movement of a shaft employing the motion of gases rising through liquids which usefully converts that motion into mechanical energy.

It is a further aim of the invention to provide an apparatus for generating rotational movement of a shaft which provides a low maintenance requirement due to the absence of moving parts and ease of repair due to the simplicity of design.

In a first aspect the invention provides an apparatus for generating rotational movement of a shaft employing the motion of gases rising through liquids, which apparatus comprises: at least one pipe coupled to and helically arranged around a central shaft, the at least one pipe, at each extremity thereof, being at least partially open ended such that the pipe can be flooded with liquid through at least one open end, with the angle of the helix being between 0 and 89 degrees relative to the longitudinal axis of the central shaft, and a fluid reservoir in fluid communication with said at least one pipe, the fluid reservoir being operable to deliver gas and/or a mixture of gas and liquid into the at least one pipe such that rotational movement is imparted on the central shaft by gas and/or liquid moving through the at least one pipe.

In certain embodiments, the angle of the helix of the pipe varies along the length of the central shaft.

In certain embodiments, the angle of the helix is from greater than 0 to about 89 degrees.

In certain embodiments, the material of the pipe may comprise one or more of the group comprising plastics, metals, alloys and rubber compounds.

In certain embodiments the pipe is formed of a rigid material.

In certain embodiments the pipe is formed of a flexible material.

In certain embodiments the pipe is formed of a flexible fabric material.

In certain embodiments, one or more of the pipe, the central shaft and the fluid reservoir are formed of a flexible material (e.g. a fabric material or the like). In this way, the structure can be inflated and weighted for the appropriate level of lift underwater.

It is much preferred that the gas is selected from the group including, but not be limited to, hydrogen, Brown's gas, air, oxygen and nitrogen.

In embodiments of the invention, the apparatus comprises a plurality of pipes helically arranged around a central shaft. More specifically, the plurality of pipes are each open at their ends so as to provide a continuous fluid conduit along the length of the central shaft. The open ends allow each pipe to be flooded with liquid, preferably water, prior to the injection of gas or a gas/liquid mixture into the pipe.

In embodiments of the invention the, or each, pipe is releasably coupled to the central shaft.

In embodiments of the invention the, or each, pipe is fixedly coupled to the central shaft. In preferred embodiments the, or each, pipe is a flexible hose.

In embodiments of the invention the, or each, pipe is entirely open ended at at least one extremity thereof. In certain embodiments, the, or each, pipe is entirely open ended at each extremity thereof. In this way, gas and/or liquid can be introduced into the pipe at an end thereof. In preferred embodiments, liquid is introduced into the pipe at a lower end thereof. Gas may be introduced with the liquid at the lowermost end of the pipe or at a separate gas injection point above the at least one end of the pipe.

In embodiments of the apparatus, the central shaft comprises a shaft body and a drive shaft, the drive shaft coupled to and retained within the shaft body. In certain

embodiments the drive shaft is fixedly coupled to the shaft body. More specifically, the rotation of the shaft body as a consequence of gas and/or gas/liquid mix moving through the pipe, is transferred to the drive shaft via a coupling between the shaft body and the drive shaft.

In embodiments of the invention, the fluid reservoir may comprise a skirt. More specifically, the skirt may define an area in which a fluid reserve is stored. The fluid may be a gas or a gas/liquid mix. In embodiments wherein the liquid flooding the pipe enters the pipe(s) at a point above the skirt, the skirt is configured to retain gas alone.

In preferred embodiments, the skirt depends from the central shaft. In certain

embodiments, the skirt is a coupled to the central shaft. More specifically, the skirt may be fixedly coupled to the central shaft.

In preferred embodiments, the skirt extends around the lower portion of the apparatus. More specifically, the skirt may extend around the entire lower portion of the apparatus.

The skirt is preferably configured to contain a fluid. More specifically, the skirt is configured to contain a gas and/or a liquid. Yet more specifically, the skirt is configured to contain a gas and/or a gas/liquid mix.

In certain embodiments, the skirt is generally conical, cylindrical or frustoconical in shape. In should be understood that the shape of the skirt is selected in order to provide suitable hydrodynamics and gas/liquid manipulation.

The skirt may be formed of a non-permeable material. More specifically, the non- permeable material may be Perspex or the like.

Alternatively, the skirt may be formed of a semi-permeable material. More specifically, the semi-permeable material may be cloth, fabric or netting. In such embodiments, the skirt may provide filtration or protection functions.

In embodiments of the invention, the fluid reservoir may comprise a compressor or a pump. In this way, gas may be delivered directly into the pipe.

In embodiments of the invention, the fluid reservoir may comprise a storage tank. More specifically, the fluid reservoir may comprise a gas or a gas and liquid storage tank. In certain embodiments, the apparatus further comprises a skirt cover. More specifically, the skirt cover may be formed of a fine or, alternatively, a coarse material.

The skirt cover preferably covers at least a part of the lower portion of the skirt. More specifically, the skirt cover covers the entire lower circumference of the lower part of the skirt.

The skirt cover is adapted to disperse or concentrate a gas, a liquid, or a mixture of both. Alternatively, or in addition, the skirt cover is adapted to filter a gas, a liquid, or a mixture of both. More specifically, the skirt cover may be adapted to filter liquid and/or gas passing into the apparatus.

In embodiments of the invention, the skirt cover is adapted to contain a gas and the energy produced by a detonation or explosion of gas. The gas and energy so produced may be used to further power the rotation of the apparatus.

The skirt and skirt cover, if present, attach to the lower part of the central shaft, and may extend some distance below the central shaft in order to maintain an enclosed volume of a gas, a liquid, or a mixture of both.

The at least one pipe preferably comprises at least one fluid inlet and at least one fluid outlet. In this way, fluid can be introduced to and removed from the at least one pipe. More specifically, the fluid inlet and fluid outlet are configured to provide for the introduction or removal of air and/or other gases and/or water and/or other liquids into and from the helical pipe(s).

In certain embodiments, the at least one fluid inlet is provided by a first open end of the pipe and the at least one fluid outlet is provided by a second open end of the pipe. In use of the apparatus, it is much by preference that the second open end of the pipe is located above the first open end of the pipe. In such arrangements, the at least one fluid inlet allows flooding of the pipe and the introduction of a gas or a gas and liquid mix into the pipe.

In certain embodiments, the at least one pipe may comprise one or more further fluid inlets and/or one or more further fluid outlets. In such arrangements, the, or each further fluid inlet may be a gas or a gas and liquid inlet into the pipe. More specifically, the further fluid inlets may be fluidly connected to the fluid reservoir. In this way, a gas or a gas and liquid mix may be injected into the pipe through the further fluid inlets. The further fluid outlets may allow the release of gas and/or liquid from the pipe. In certain embodiments, the, or each, helical pipe comprises a plurality of additional, separate inlets and outlets. More specifically, the additional separate inlets and outlets may be spaced along the at least one pipe. Yet more specifically, the additional separate inlets may be fluidly connected to the fluid reservoir. In this way, a gas or a gas and liquid mix may be injected into the pipe through the additional separate inlets. The additional separate outlets may allow the release of gas and/or liquid from the pipe.

In certain embodiments the lower surface of the, or each, helical pipe comprises at least one hole, typically a plurality of holes (e.g. perforations). In this way, the additional outlets (e.g. perforations) allow liquid within the pipe(s) to move out of the way of the rising gas or gas/liquid mix in the pipe(s).

In certain embodiments, the holes in the lower surface of the, or each helical pipe are spaced apart along the length of the pipe(s). More specifically, the holes in the lower surface of the, or each helical pipe are spaced apart every 1 mm to 2 metres along the length of the pipe(s).

In certain embodiments, the at least one hole comprises an elongate channel along the length of the lowermost surface of the pipe(s). The elongate channel may be continuous, alternatively, the elongate channel is formed of a number of discrete sub-channels along the length of the lower surface of the pipe(s).

In certain embodiments the pipe(s) is braced by bracing elements to hold it in place on the central shaft.

In certain embodiments the bracing elements are one or more of tensioned wires and struts.

In other embodiments, one or more tee pieces may be connected to the helical pipe and also to the fluid reservoir, being a gas supply, allowing gas or gas bubbles to be supplied into the helical pipe. More specifically, gas may be fed into the tee piece(s) via an airlock type system comprising of a 'U' shaped pipe, which in turn is fed via one or more manifolds attached to a hollow drive shaft or pipe acting as the drive shaft.

The fluid inlets and fluid outlets may vary in number depending upon one or more of: the size and use of the apparatus, the number and size of the helical pipes, and their arrangement around the central shaft.

In embodiments comprising at least one pipe coupled to and helically arranged around a central shaft, a fluid reservoir, and at least one fluid inlet and at least one fluid outlet in the at least one pipe to allow flooding of the pipe, and at least one gas or gas and liquid inlet and at least one gas or gas and fluid outlet in the at least one pipe the combination of features creates a cell. In such arrangements, the apparatus for generating rotational movement of a shaft employing the motion of gases rising through liquids comprises at least one cell in which the skirt is in fluid communication with said at least one pipe, the skirt being adapted to deliver gas and/or liquid into the at least one pipe such that rotational movement is imparted on the central shaft by gas and/or liquid moving through the at least one pipe.

In embodiments, the fluid inlet and the at least one gas or gas and liquid inlet may be one and the same.

In embodiments, the fluid outlet and the at least one gas or gas and liquid outlet may be one and the same.

In embodiments, the fluid inlet and the gas or gas and liquid inlet are separate inlets to the pipe.

In embodiments, the fluid outlet and the gas or gas and liquid outlet are separate outlets to the pipe.

In embodiments, the fluid reservoir may comprise a skirt and, if present, a skirt cover.

The apparatus, in embodiments thereof, may comprise a plurality of cells. More specifically, the cells are stacked one upon another and in fluid communication with one another such that gas and/or liquid passing through the helically wound pipe of a first cell is fluidly connected to the helically wound pipe of a second cell. Thus, gas entering the pipe of the first cell is able to travel through the first cell and into the pipe of the second cell. In this way, rotational movement may be imparted on both the first and the second central shafts, or further energy transferred to a single, longer central shaft.

In certain embodiments, the apparatus may also comprise additional components to enhance its structural strength and/or to improve its weight/size to energy conversion ratio. These additional components may include lightweight lattices or rigid foams, composite or metallic structures, or the creation of free space within the cell.

In use, the cell is wholly submerged within a liquid and the open-ended skirt and the open-ended at least one pipe partially or entirely flooded. In subsea applications, flooding of the cell is achieved by placing the cell into the water, with associated structures and apparatus either submerged alongside the cell or held on the surface. In land-based applications, the cell is submerged in a tank, pipe, shaft, or other structure capable of holding the requisite liquid to submerge the cell and allow free movement of it. A gas, or gas and liquid mixture, or sequence of gas and liquid, is applied to the lower part of the cell via equipment found either within the cell, or via external structures and apparatus and connected, either permanently or temporarily, to the cell, or within the immediate vicinity of the cell.

The associated/external structures and apparatus may comprise one or more of: a monitoring station, pipes, a compressor, a vacuum pump, a liquid pump, a valve assembly, a diffuser and a purge or lift gas manifold.

The apparatus may further comprise a gas delivery system. More specifically, the gas delivery system is fluidly connected to the at least one pipe(s) and/or to the area defined by the skirt. The area defined by the skirt is the skirted area. Alternatively, the gas delivery system may be fluidly connected to the drive shaft, which is hollow, and from there via manifolds to the helical pipe or pipes. It is much preferred that the gas delivery system is fluidly connected to the fluid reservoir. In this way, a gas or a gas and liquid mix may be delivered from the fluid reservoir, via the gas delivery system, to the at least one pipe.

The apparatus may further comprise a gas generating system. More specifically, the gas generating system is fluidly connected to the gas delivery system. In this way, gas generated by the gas generating system can be delivered directly to the gas delivery system.

In embodiments of the invention, the apparatus comprises a gas compressor operable and located to inject gas jets or bubbles directly into the helical pipe(s) of the cell. In use of the apparatus, the gas compressor operates to inject gas into the flooded helical pipe(s).

In embodiments of the invention the, or each, helical pipe comprises fluid inlets in the form of apertures along at least a lower portion thereof. In this way the, or each, helical pipe may be further flooded with liquid through the apertures in order to provide a structured gas/liquid introduction sequence within the helical pipe(s). By way of the structured gas/liquid introduction sequence it is possible to direct, stabilise and otherwise control the interaction between the inner walls of the helical tube(s) and the gas or air mixture, or gas and air sequence. More specifically, the sequence of gas and liquid within a helical pipe as the gas rises through the liquid imparts differing levels of energy to the pipe walls; a larger proportion of gas in a certain liquid may produce additional energy transfer, whereas the opposite may be true in a different liquid/gas combination. Further, the amount of gas and liquid in each helical tube influences the torque and/or rotational speed and rotational balance of the turning central shaft. Without wishing to be bound by theory, it is thought that the contact of the gas/air with the pipe walls that causes the rotation of the central shaft.

In embodiments of the invention, a gas or gases are evolved by either chemical, electrical or other means and introduced into the flooded cell and, in particular, into the skirt and/or the helical pipe(s) in a manner that creates a pulsed sequence of gas and liquid. In certain embodiments, the gas or gases are introduced in pulses to the liquid within the cell skirt. The gas is detonated or otherwise caused to react or combine with another gas(es) and/or liquid to produce further products or pressure which enhances or otherwise controls, directs or stabilises the interaction between the inner walls of the helical pipe(s) and the gas and liquid mixture, or gas and liquid sequence.

In embodiments of the invention, the central shaft may comprise a shaft body. The shaft body may enclose a void. More specifically, the shaft body may define a hollow tank or pipe. It is much by preference that the tank is fluidly connected to the at least one pipe(s).

The tank or pipe may provide a fluid reservoir being a sealed tank or conduit for storing and/or delivering gas. The gas may be delivered and/or stored at either ambient pressure or at pressure above ambient.

In embodiments of the invention, the tank and/or pipe is fluidly connected to the at least one further pipe(s). In this way, gas stored within the tank can be piped directly to each flooded helical tube, or directly to the skirted area beneath the cell. This replaces or supplements a separate gas generating or delivery system not directly attached to the cell.

In embodiments of the invention, the interior of the helical pipe(s) is textured, profiled or otherwise treated to provide resistance to the flow of the gas through the liquid and the liquid's behaviour as it interacts with the gas. In this way, in use of the apparatus, further drag is created on the interior helical pipe walls which is, in turn, transferred into rotation of the central shaft.

In certain embodiments, the interior surface of the, or each, helical pipe wall may comprise rifling, such as pitting of the surfaces in a pattern and/or ridge and valley profiling or corkscrew or other designs.

In embodiments of the invention, the interior surface of the, or each, helical pipe may be formed from or coated with material which increases gas-to-surface resistance and/or liquid to surface resistance. Such materials may include rubber and fabric, for example, specifically for the purposes of generating further transfer of motion from vertical movement of gas or gas and liquid within the helical pipe to rotation of the cell's central shaft and/or for controlling the amount of energy transferred.

In embodiments of the invention, the apparatus may further comprise an outer skin. More specifically, the outer skin encloses the cell. In a preferred embodiment, the cell is enclosed by an outer skin which is configured to contain at least one gas. The gas contained within the outer skin may be stored therein at ambient pressure or at a pressure above ambient pressure.

In embodiments of the invention, the fluid reservoir may comprise an enclosed skirt. More specifically, the enclosed skirt depends from the central shaft. Yet more specifically, the enclosed skirt is in fluid communication with the at least one helical pipe such that gas and/or liquid in the enclosed skirt can be transferred into the pipe in order to impart rotational movement on the central shaft. In use of the apparatus, the enclosed skirt is configured to contain flammable gases in the presence of accelerants and oxygen evolving gases or compounds (appropriate for the assistance of ignition and/or continual or staged burning whilst immersed in liquid). The flammable gases may comprise hydrogen and/or Brown's gas. In use of the apparatus, the resultant pressurised gas and/or liquid are employed to further drive the central shaft via the interaction between the gas and the inner surface of the helical pipe(s).

A substantial advantage of the apparatus of the invention is that it provides a means of producing useful rotational movement from ambient pressure or pressurised gas or gas and liquid combinations via a simple and low maintenance structure,

The apparatus of the invention eliminates or reduces the use of moving parts constructed of often expensive materials which function in a more energy inefficient manner.

A further advantage of the apparatus of the invention is that it can be used to contribute to, or replace, present methods of generating electrical power.

An additional advantage of the apparatus of the invention is that, when deployed in open water, the cell will require no shell nor rigid outer component. Save for netting to exclude sea life and large debris, the cell will perform without the need fora substantial cowl or enclosure, eliminating the costs of the same and further enabling access for maintenance or repair.

It will be understood that the size of the cell is restricted only by the available depth and expanse of liquid where deployment takes place. For example, in water, the height and width of the cell is limited only by the area of protected water available. On land, cell size is limited only by the size of enclosure available in which to fully submerge the cell. In embodiments of the invention, the apparatus further comprises microchannels operable to direct micro bubbles of gas to the outer surface of the, or each, cell. In this way, the microbubbles of gas serve to reduce friction between the liquid in which the apparatus is submerged and the outer surface of the cell.

In embodiments of the invention, multiple helical pipes may be wound around and connected to the central shaft of a, or each, cell.

In certain embodiments of the invention, the apparatus further comprises a pipe retaining plate. The pipe retaining plate is preferably located at a first end of the central shaft. More specifically, the, or each, pipe may be coupled to the pipe retaining plate at an end of the, or each, pipe. In this way, it is possible to both quickly and easily fix one end of all helical pipes in their desired formation around the central shaft into the pipe retaining plate, situated at one end of the central shaft.

The apparatus may further comprise a further pipe retaining plate. The further pipe retaining plate is preferably located at a second end of the central shaft opposite the first end of the central shaft. In this way, downward pressure and rotation is applied to the second pipe retaining plate at the opposite end of the shaft. This has the effect of transitioning all pipes from a vertical path to a helical path around the central shaft, at a chosen angle of ascent.

In embodiments of the invention the, or each, helical pipe(s) may be fixed into the pipe retaining place by one or more of: mechanical joints, glue and other fixing means to produce the completed helical winding of pipes around the central shaft.

In embodiments of the invention, the entire cell may be covered by at least one of: an additional skin, netting, alloy, composite material and a space frame. Such additional components provide further fixing and rigidity for the system comprising one or a number of cells and/or for the purposes of other application considerations, including but not limited to, connecting a load, cabins and other areas designed for human use, connecting propulsion sources, fuel storage, gas production, quarters, advertising, lightning conductivity, solar cells and the like.

The additional skin or outer skin of the complete cell or cells may comprise pores, either of nanoscale or larger, which pores may be open or able to seal or otherwise restrict the flow of liquid or gases to and/or from or interacting with the outer skin surface. More specifically, the pores operate to provide pressure or vacuum to encourage laminar or other hydro dynamically beneficial liquid or liquid/gas flows over what may be the substantial outer bulk of certain sizes of cell, whilst also providing an alternative means of controlling the trim and/or direction and/or rotation and/or propulsion for the cell, and a means of producing pressure or vacuum to remove or reduce the accumulation of ice or other solids either by the direct or indirect application of liquid, gas or another

combination of gases, and/or liquids, or by the flexing of the outer skin via the action of liquid, gas or another combination of gases and/or liquids and gases.

In a second aspect, the present invention provides a system for generating rotational movement employing the motion of gases rising through liquids, which system comprises a plurality of apparatus according to the first aspect of the invention.

In preferred embodiments, the system comprises a plurality of cells fluidly coupled with one another such that gas and/or liquid is transferrable from one cell to another cell. In this way, gas and/or liquid transferring from one cell to another can undertake further useful work in the subsequent cell.

In the first and/or second aspect of the invention, each of the cells may be connected to another cell as a separate, demountable component, each of which fulfils the functions of a cell. Such a system may be connected to larger compressors and electrical generator components to make a more substantial system when required.

It is much by preference that the, or each, cell can be repaired or replaced.

It is much by preference that other components of the apparatus, such as the separate external gas, liquid compressors, pumps or electrical generators can be removed, repaired and/or replaced with relative ease and simplicity and the minimum of

engineering support.

An advantage of the cell structure of the apparatus and system of the invention are the benefits of the insulation effects offered by the structure in this particular application. Specifically, the warming effects of the energy transfer, and the relative chilling effects of large open areas of liquid in which the apparatus or system are submersed, can be balanced for maximum beneficial effect when sizing and designing a specific cell for a specific application or environment.

In the first and second aspect of the invention, the apparatus or system may further comprise control equipment. More specifically, the control equipment may comprise additional structural components or other operational components. In certain

embodiments the operational components may be one or more of: pumps, compressors, actuated valves, electrical generation equipment, programmable logic controllers (PLC), brakes and start up motors. Such additional structural components and/or other operational components may be located within the cell, or beneath, above, in front or behind the cell.

The operational components may comprise at least one means to convert the rotational movement of the central shaft into electrical energy. The conversion means may be provided by the turning of an electrical generator or alternator either directly or via gears.

In embodiments of the invention, the apparatus may comprise additional surfaces, which additional surfaces are adapted to interact with a gas and/or liquid in the apparatus to impart rotational movement on the central shaft or otherwise increase the efficiency of the operation of the apparatus. In certain embodiments, the additional surfaces may comprise the outer surfaces of the helical pipes enclosed in a multi-layered bundle of pipes around the central shaft. In additional, or alternative, embodiments, the additional surfaces may be provided by a static outer sleeve around the central shaft. In such embodiments, rising bubbles of gas between the central shaft and the outer sleeve act to reduce drag on the rotating outer part of the central shaft produced by the liquid in which it is submerged.

In order that the invention be easily understood and readily carried into effect, reference will now be made, by way of example only, to the accompanying drawing in which:

Figure 1 shows a schematic view of an apparatus according to an embodiment of the invention.

Figure 2 shows a schematic view of an apparatus according to an alternative

embodiment of the invention;

Figure 3 shows a schematic view of a system according to the second aspect of the invention;

Figure 4 shows a schematic view of the apparatus of Figure 1 enclosed in an outer skin;

Figure 5a shows a schematic view of an apparatus according to an embodiment of the invention in which gas is delivered via a conduit through the drive shaft; and

Figure 5b shows an exploded view of the portion "C" of the apparatus of Figure 5a.

Detailed Description of the Invention

Figure 1 depicts an apparatus 1 for generating rotational movement of a drive shaft 3 employing the motion of gases rising through liquids. The apparatus 1 comprises a flexible pipe 5 coupled to and helically wound around a central core 7. In the depicted arrangement, the central core 7 is a hollow tank surrounding and coupled to a drive shaft 3. Pipe 5 comprises an opening 9 at one end thereof forming a fluid inlet in the pipe. At the other end of pipe 5 is a fluid outlet 1 1. The flexible pipe 5 is wound around and attached to central core 7 with the angle of the helix being between 0 and 89 degrees relative to the longitudinal axis of the drive shaft 3. A fluid reservoir is provided by a skirt 13. Skirt 13 depends from and is attached to the lower portion of central core 7. The skirt 13 is in fluid communication with the fluid inlet 9 at the end of pipe 5.

The depicted apparatus forms a cell.

Drive shaft 3 is attached to at least one means (not shown) to convert the rotational movement of the central core 7 and drive shaft 3 into electrical energy. The conversion means may be provided by the turning of an electrical generator or alternator either directly or via gears.

In operation of the apparatus, the cell 1 is submersed in liquid and the helical pipe 5 flooded with that liquid through an open end 9 of the pipe 5. Gas is introduced into the fluid reservoir, skirt 13, which is in fluid communication with gas inlet 9 at the end of pipe 5. The injection of gas into the flooded pipe 5 causes the gas to move through the pipe 5 and the movement of the gas through the fluid in the flooded pipe 5 in the direction shown as "A" in Figure 1 causes rotation of the central core 7 coupled to drive shaft 3 in the direction of arrow "B". Gas and/or fluid escapes from the helical pipe 5 through fluid outlet 1 1 at the opposite end of the pipe 5. In embodiments not shown, gas may be recaptured at fluid outlet 1 1 and fed back to skirt 13 to be recycled back into the process.

The fluid reservoir 13 retains and delivers gas into the pipe 5 such that rotational movement is imparted on the drive shaft 3 by gas moving through the pipe 5.

In an alternative embodiment, not shown, the apparatus further comprises a separate gas inlet located in the lower portion of the helical pipe 5. In such arrangements, liquid is introduced into helical pipe 5 through the fluid inlet 9. A gas inlet (not shown), is located above the fluid inlet 9 and allows gas to be delivered into the flooded pipe 5. The gas inlet is preferably fluidly connected to a gas delivery manifold which is in turn coupled to a gas delivery/storage tank. The combined liquid and gas will exit the pipe 5 through the open end of the pipe forming fluid outlet 1 1.

Figure 2 shows an alternative apparatus 1 in which a bundle of flexible pipes 5 are coupled to and wound around central core 7. Each pipe 5 of the bundle is open at its ends to provide fluid inlets 9 and fluid outlets 1 1. Each fluid inlet 9 of each pipe 5 is in fluid communication with the fluid reservoir in skirt 13. In use, the gas in skirt 13 is released into each pipe 5 via the fluid inlets 9. The gas rises through the liquid in the flooded pipes 5 and the movement of gas through the helical path of the pipes causes the central core 7 and the draft shaft 3 to rotate.

Figure 3 depicts a system of the invention comprising two cells 27a and 27b stacked one on top of the other. Each cell 27a, 27b comprises a flexible pipe 5a, 5b coupled to and helically wound around a hollow central core 7a, 7b. In the depicted arrangement, the central core 7a, 7b of each cell is a hollow tank surrounding and coupled to a drive shaft 3a, 3b.

A connecting pipe 22 fluidly connects the fluid outlet 1 1 a of pipe 5a of the first cell 27a to the fluid inlet 9b of the pipe 5b of the second cell 27b. The fluid inlet 9a of the first cell 27a is fluidly coupled to skirt 13a which depends from the central core 7a of the cell 27a. The skirt 13b of the second cell 27b is coupled to the upper portion of the central core 7a of the first cell 27a and to the lower portion of the central core 7b of the second cell 27b.

Gas contained in the reservoir bounded by skirt 13a is released into the fluid inlet 9a of the first cell 27a. The gas travels through pipe 5a and interacts with the inner surfaces of the pipe 5a and the liquid contained therein. The interaction of the gas with the pipe 5a and the liquid contained in the pipe causes the central core 7a and draft shaft 3a to rotate. As the gas reaches the fluid outlet 1 1 a at the end of pipe 5a in cell 27a, the gas continues to travel through connecting pipe 22 and into the fluid inlet 9b in the pipe 5b in the second cell 27b. The gas continues to rise in the pipe 5b in the second cell 27b. The interaction of the gas with the pipe 5b and the liquid contained in the pipe causes the central core 7b and draft shaft 3b to rotate.

Figure 4 shows the apparatus of Figure 1 enclosed in an outer skin 37. The outer skin 37 provides protection for the apparatus 1 whilst also providing a means of reducing hydrodynamically created friction.

In each of the depicted embodiments, the drive shaft 3 is coupled, either directly or via a gear train, to an electrical generator or alternator (not shown). In use of the apparatus 1 , the device is submerged in a body of water and the pipes flooded with water through the open ends of the, or each pipe. Gas is generated or provided from a storage tank, or directly via a pump or compressor, then delivered either directly to the helical pipe or pipes, or to the reservoir bounded by skirt 13. The apparatus 1 is now primed for use. In certain arrangements, it may be necessary to provide a device for starting the rotation of the central core and the drive shaft, after which the gas lift within the pipe(s) continues the rotation. The start sequence may include an electric motor or a manual wheel attached to the drive shaft 3 which operate to initiate the rotation of the cell, after which the gas lift maintains and/or increases that initial rotation speed. Gas is then released into the inlet 9 of pipe 5 and travels through the water contained in the flooded pipe 5. The movement of the gas through the water in the pipe 5 causes the central core 7 to which the pipe 5 is coupled and the drive shaft 3 to which the central core 7 is coupled to rotate. Gas is continuously injected into the inlet 9 of the pipe 5 until rotation is no longer required. Gas reaching the end of pipe 5 is released from the apparatus 1 through outlet 1 1. In embodiments now shown, it is envisaged that a gas recycling line may be provided from outlet 11 to the reservoir bounded by skirt 13.

Figure 5a shows a schematic view of an apparatus 1 in which gas is delivered to helical pipe 5 via a conduit 41 which is coupled to hollow drive shaft 3 by a rotatable coupling 42. A gas generating device (not shown) is connected in fluid communication with conduit 41 which in turn is coupled to the helical pipe 5 at a lower portion thereof by rotatable coupling 42. Gas from the generating device, is injected into conduit 41 and travels up through the coupling 42 into the hollow draft shaft 3. Exploded section "C", as best seen in Figure 5b, shows the connection of hollow draft shaft 3 with helical pipe 5. Drive shaft 3, enclosed by the central core (not shown in Figure 5b) is connected at a first end of a "U-shaped" airlock 43. The second and opposite end of the airlock 43 is fluidly

connected to the helical pipe 5 in a tee section. In this way, gas is delivered via the rotating hollow drive shaft 3, through conduit 41 from a gas generating device (not shown), to the airlock 43 and into helical pipe 5 via a tee piece (not shown). In certain arrangements, the drive shaft 3 may be fitted with one or many manifolds (not shown) and gas delivered via that manifold and into airlock 43.