GB2337089A

GB2337089A - Apparatus for generating electrical energy by utilising pressure differentials as a body is submerged in liquid

Info

Publication number: GB2337089A
Application number: GB9903698A
Authority: GB
Inventors: Jonathan Moore
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-02-20
Filing date: 1999-02-19
Publication date: 1999-11-10
Also published as: GB9803495D0; GB9903698D0

Abstract

An apparatus 10 for generating electrical energy comprises a plurality of generating units 24 mounted on a wheel 12 which is submerged in a liquid. Each generating unit 24 comprises a variable volume container 28 having a movable wall portion, preferably a piston 26, and an electricity generator 32 for converting movement of the piston 26 into electrical energy. In use, rotation of the wheel 12 causes the generating units 24 to move between positions of different submerged depths so that the pressure exerted on them varies. This variation in pressure cause the pistons 26 to reciprocate which in turn drives the generators 32 via a gearing mechanism 30. The generators 32 may be either dynamos or alternators. The wheel is made to rotate either by an electric motor (figure 3) or by introducing air 22, at depth, into pockets 20 mounted on the wheel 12 to make the pockets buoyant.

Description

2337089 1 ELECTRICITY GENERATOR The present invention relates to an

apparatus for generating electrical energy.

According to the present invention, there is provided an apparatus for generating electrical energy, said apparatus comprising:

a plurality of generating units mounted on a rotatable body, said rotatable body being adapted to be submerged in a liquid so that a pressure differential is established across the height of said body, each generating unit comprising a variable volume container having a movable wall portion for containing a compressible fluid and electricity generation means for converting movement of said wall portion into electrical energy.

whereby, in use, rotation of said rotatable body causes the pressure exerted on each generating unit to vary, said variation in pressure causing movement of said wall portion.

The body may be rotated by, for example, mechanical, electrical or hydraulic means. In one embodiment, the rotatable body is provided with a plurality of peripheral pockets. In operation, air is directed into the pockets positioned at a lower side of the body. The buoyancy of the air trapped in the pockets produces an upward force tending to rotate the body. As the body rotates and the pockets move towards or across the highest point of rotation, the air is released from the pockets. By varying the rate at 2 )o which air is introduced into the pockets and altering the size of the pockets, the rate of rotation of the body may be controlled.

In another embodiment, an electric motor drives the rotating body, conveniently by driving a sprocket or the like which engages a corresponding circular track on the body.

The rotatable body may take the form of a large wheel between 5 and 20 metres in diameter. In a preferred embodiment, the wheel is approximately 10 metres in diameter.

Mounted to the rotatable body are a plurality of generating units. Preferably, the generating units are mounted circumferentially, around the periphery of the rotatable body.

Each generating unit may comprise a piston slidably mounted in a housing. Conveniently, the housing contains air or some other compressible gas and the piston forms a gas-tight seal with the housing.

The position of the piston relative to the housing is related to the external pressure. An increase in external pressure causes the piston to move inwards, compressing the fluid in the housing. When the external pressure decreases, fluid in the housing expands and pushes the piston outwards. This linear movement is converted into electrical energy by the electricity generation means. In a preferred embodiment, the electricity generating means comprises a dynamo or alternator.

3 The electricity generating means may also include a gearing system for converting the movement of the piston to rotational movement. For example, the piston may be provided with a longitudinal member which defines a gear rack for engaging a series of gear wheels. The longitudinal member may be in the form of a rod which extends into the housing. In operation, linear movement of the rod causes the gear wheels to rotate to drive a dynamo or alternator.

Advantageously, the gearing system is adapted to ensure that the dynamo or alternator is rotated in one direction irrespective of the direction of movement of the piston.

These and other aspects of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a schematic view of an apparatus in accordance with an embodiment of the present invention; Figure 2 is a sectional view of a generating unit of the apparatus of Figure 1; Figure 3 is a schematic view of an apparatus in accordance with a further embodiment of the present invention; and Figure 4 is a plan view of the apparatus of Figure 3.

Reference is first made to Figure 1 of the drawings which depicts an apparatus in accordance with an embodiment of the present invention.

The apparatus 10 is located in a large-wate-r tank 14 is and comprises a carrier wheel 12 which is rotatably mounted about a central axis 16 on a support frame 18. The wheel 12 is approximately 10 metres in diameter.

The outer surface of the wheel 12 is provided with a plurality of pockets 20. An air pump is positioned at the base of the tank 14 to direct air from the surface into the water. In use, air 22 is introduced into the pockets 20 at position "P". The buoyancy of the air 22 trapped within the pockets 20 creates an upward force on the pockets 20, causing the wheel 12 to rotate in the water. As the wheel 12 rotates past position "Q", the air 22 is released from the pockets 20 and displaced by water.

Mounted within the circumference of the wheel 12 are a plurality of generating units 24, only five of which are shown in Figure 1. Each generating unit 24 measures approximately 20 cm in diameter. Thus, 153 units are positioned around the circumference of the wheel 12. 147 units are accommodated in the next "layer", and 141, 135, and 128 units respectively are accommodated in subsequent layers.

As shown in Figure 2, each generating unit 24 comprises a piston 26 slidably mounted within a cylindrical housing 28.

The position of the piston 26 relative to the housing 28 is related to the external water pressure. As the water pressure increases, the piston moves inwards, compressing the air in the housing. As the water pressure decreases, the air in the housing 28 expands and pushes the-piston 26 outwards. This linear movement is converted into rotational energy by a gearing system 30 which drives a dynamo 32 to generate electricity.

1 The gearing system 30 comprises a rod 34 and a series of gear wheels 36a, b,c,d,e,f,g. The rod 34 is coupled to the piston 26 and defines a gear rack for engaging a cog 40 which is axially slidable within a slot (not shown). The cog 40 may be actuated to rotate the gear wheels 36, as described below.

In operation, the carrier wheel 12 is rotated by introducing air 22 into the pockets 20 at position "P". As a generating unit 24 is moved downwards through the water, the water pressure exerted on the piston 26 increases. This causes the piston 26 to move inwards in the direction W, compressing the air in the housing 28. Movement of the piston 26 causes the rod 34 to engage the cog 40 and slide the cog 40 into engagement with the gear wheel 36a. As the piston 26 moves further inwards, the cog 40 rotates in an anti-clockwise direction. This drives the gear wheel 36a clockwise, rotating a larger gear wheel 36d anti-clockwise.

As the generating unit 24 moves upwards through the water, the water pressure acting on the unit 24 decreases. Accordingly, the air in the housing expands, pushing the piston 26 outwards in the direction "B". The rod 34 also moves outwards, causing the cog 40 to slice out of contact with the gear wheel 36a and into engagement with another gear wheel 36b. As the rod 34 moves further outwards, the cog 40 is rotated clockwise, driving gear wheel 36b 6 anticlockwise. This causes gear wheel 36c to rotate clockwise, driving the large gear wheel 36d in an anticlockwise direction. The arrangement ensures that the dynamo 32 rotates in the same direction irrespective of the direction of movement of the rod 34.

Reference is now made to Figures 3 and 4 of the drawings, which illustrate apparatus 50 in accordance with a further embodiment of the invention. The apparatus 50 is generally similar to the apparatus of the first described embodiment, however the generating unit carrier wheel 52 of this embodiment is driven by an electric motor 54, mounted on an upper portion of the support frame 56, and stabilised by a retaining strut 57 extending from the side of the tank. The motor 54 drives the wheel 52 via a gearbox 58 and a toothed sprocket 60 which engages a corresponding circular track 62 defined around the circumference of the wheel 52.

Various modifications may be made to the embodiment_s described above without departing from IL:-he scope of the invention. For example, the number of gear wheels used and the relative sizes of the gear wheels in the generating units may be altered as required to produce the desired output. Further, the number of generating units mounted within the carrier wheels may be varied as required.

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Claims

1. An apparatus for generating electrical energy, said apparatus comprising: a plurality of generating units mounted on a rotatable body, said rotatable body being adapted to be submerged in a liquid so that a pressure differential is established across the height of said body, each generating unit comprising a variable volume container having a movable wall portion for containing a compressible fluid and electricity generation means for converting movement of said wall portion into electrical energy, whereby, in use, rotation of said rotatable body causes the pressure exerted on each generating unit to vary, said variation in pressure causing movement of said wall portion.

2. The apparatus of claim 1, wherein the body is rotated by electric motor.

3. The apparatus of claim 1, wherein the rotatable body is provided with a plurality of peripheral pockets and means is provided for directing air into the pockets positioned at a lower side of the body, the buoyancy of the air trapped in the pockets producing an upward force tending to rotate the body.

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4. The apparatus of any of the preceding claims, wherein the rotatable body is a wheel between 5 and 20 metres in diameter.

5. The apparatus of claim 4, wherein the wheel is approximately 10 metres in diameter.

6. The apparatus of any of the preceding claims, wherein a plurality of generating units are mounted to the rotatable body.

7. The apparatus of claim 6, wherein the generating units are mounted circumferentially, around the periphery of the rotatable body.

8. The apparatus of any of the preceding claims, wherein each generating unit comprises a piston slidably mounted in a housing.

9. The apparatus of claim 8, wherein each housing contains a compressible gas and the piston forms a gastight seal with the housing.

10. The apparatus of claim 9, wherein linear movement of the piston in the housing in response to changing external fluid pressure is converted into electrical energy by the electricity generation means.

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11. The apparatus of any of the preceding claims, wherein the electricity generating means comprises a dynamo or alternator.

12. The apparatus of claim 11, wherein the electricity generating means includes a gearing system for converting linear movement of the piston to rotational movement.

13. The apparatus of claim 12, wherein the piston is provided with a longitudinal member defining a gear rack for engaging a gearing system

14. The apparatus of claim 13, wherein the gearing system is adapted to ensure that the dynamo or alternator is rotated in one direction irrespective of the direction of movement of the piston.

15. The apparatus substantially as described herein and as illustrated in the accompanying drawings.