GB1604372A - Apparatus for deriving power from a rise or fall of a liquid level - Google Patents

Description

(54) APPARATUS FOR DERIVING POWER FROM A RISE OR FALL OF A LIQUID LEVEL (71) I, MALCOLM ALVA FIDELIS D'RosARro of 22 Oaktree Avenue, Palmers Green, London, N.13, a British subject, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be per- formed, to be particularly described in and by the following statement : This invention relates to apparatus for deriving power from a rise or fall in the level of a body of liquid, e.g. the sea.

In the past numerous proposals have been made to harness the effect of the tides in order to derive useful power therefrom.

However a common problem to all such methods is that the power cannot be obtained exactly when required, irrespective of the state of the tide. Accordingly a cheap easy and convenient way of storing the energy derived from the rise and fall of the tide would be advantageous. One method of achieving this is to use the retention of a body of gas compressed or rarefied by the action of the tide through some apparatus such as a storage means. A method of using compressed air as a energy storage means for the utilisation of tidal energy is disclosed in UK patent specification 384,844. In this a complex series of compressors, storage tanks, valves and the like is used to store air compressed indirectly as a result of air being forced through a motor 15 (see the Figure in UK 384,844) by the rise of the tide within a tank open only to the sea and to the motor.

However such an apparatus is mechanically complex and is only intended to operate during a rising tide. It would thus be advantageous to provide an apparatus capable of utilising both the rise and fall of the tide to compress or rarefy air which is simple in both construction and use and which may be used to store such tidal energy.

The present invention provides an apparatus for deriving power from a rise or fall in the level of a body of liquid comprising a first tank member which said liquid level moves relative to and a second buoyant tank member which cooperates in a gas tight manner with said first tank member so as to form a gas tight tank within which a gas is compressed or rarefied on the rise or fall of said liquid level such that the compressed gas or partial vacuum may be used as a source of power.

The present invention may further provide means for preventing relative movement of said first and second tank members after said gas has been compressed or rarefied so that the gas may be retained in its compressed or rarefied state.

An embodiment of the present invention will now be described in more detail by way of example with reference to the accompanying drawing.

In the accompanying drawing an apparatus according to the present invention is shown standing on the sea bed 1 in an area where the sea levels at low and high tide are shown at 2 and 3 respectively.

The apparatus is supported on a tripod base 4 resting on the sea bed 1. Attached to the base 4 is a central cylindrical support 5 to which a cylindrical upper tank member 6 having a closed upper end 7 is rigidly attached by the upper end 7.

A second cylindrical tank member 8 having a closed lower end is provided which cooperates slidingly and sealingly with the outer cylidrical wall of the first tank member 6. $ihe second tank member 8 is also provided with an inner cylindrical wall 9 which fits slidably and sealingly over the central support 5 so that the first and second tank members may slide relative to one another so as to provide a tank of variable volume. The second tank member 8 is further provided with a flotation collar 10 having a frusto-conical outer wall, to render it buoyant such that it rises and falls with the sea level 2,3.

Connections 11,12 are provided in the top of the fixed tank member 6, and in use are connected to power-generating means, e.g. a turbine. In operation, as the water level rises, the air in the tank 6,8 is compressed and is used to drive the turbine.

As the water level falls, the air is rarefied, and the resultant partial vacuum can again be used to drive the turbine.

In addition, the apparatus is provided with a rubberised compressible sleeve 13 to form a watertight protection for the lubricated outer bearing surface of the central cylinder 5 on which the second tank member 8 slides.

The apparatus is also provided with a telescopic hydraulic locking means compfls- ing an inner cylinder 15 attached to the base 4 and a cooperating outer cylinder 14 attached to the tank member 8 by lugs 20 protruding through slots 21 in the support 5. The base 4 is utilized as a hydraulic fluid reservoir 16. The cylinders 14,15 slide apart on the rise of the second tank member 8 and when this occurs fluid 16 is drawn into the cylinder from the reservoir in the base 4 via a pipe 17. When the pressure in the tank reaches a set value measured by a sensor 18 a valve 19 in pipe 17 is closed so that the second tank member is locked in its upper most position.

The air in the tank may thus be retained in a compressed state, with suitable valving to control the air flow from the connections 11,12 until it is desired to use it irrespective of the state of the tide.

In an alternative mode of operation, a partial vacuum is created when the outer lank member 8 sinks as the tide falls, and the vacuum sensed by the sensor 18 is caused to close the valve 19 to lock the tank members 6,8 to store the vacuum for subsequent use.

WHAT I CLAIM IS:- 1. An apparatus for deriving power from a rise or fall in the level of a body of liquid comprising a first tank member which said liquid level moves relative to and a second buoyant tank member which cooperates in a gas tight manner with said first tank member so as to form a gas tight tank within which a gas is compressed or rarefied on the rise or fall of said liquid level such that the compressed gas or partial vacuum may be used as a source of power.

2. An apparatus according to claim 1 wherein the two tank members are annular as seen in plan view and have respective outer cylindrical walls which cooperates slidably and sealingly, the first tank member having a closed upper end and being mounted on a support comprising a support member extending axially through it and the second tank member having a closed lower end slidably and sealingly cooperating with said support member.

3. An apparatus according to claim 2 wherein said outer wall of the second tank member is radially outside the outer wall of said first tank member and is attached to a buoyant collar surrounding it.

4. An apparatus according to any one of claims 1 to 3 further comprising means for preventing relative movement of said first and second tank members so that said compressed gas or partial vacuum may be retained.

5. An apparatus according to claim 4 wherein said means for preventing'relative movement of said tank members comprise a telescopic hydraulic fluid container and a valve controlling fluid flow into and out of the container.

6. An apparatus for deriving power from a rise or fall in the level of a body of liquid substantially as herein described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. be used to drive the turbine. In addition, the apparatus is provided with a rubberised compressible sleeve 13 to form a watertight protection for the lubricated outer bearing surface of the central cylinder 5 on which the second tank member 8 slides. The apparatus is also provided with a telescopic hydraulic locking means compfls- ing an inner cylinder 15 attached to the base 4 and a cooperating outer cylinder 14 attached to the tank member 8 by lugs 20 protruding through slots 21 in the support 5. The base 4 is utilized as a hydraulic fluid reservoir 16. The cylinders 14,15 slide apart on the rise of the second tank member 8 and when this occurs fluid 16 is drawn into the cylinder from the reservoir in the base 4 via a pipe 17. When the pressure in the tank reaches a set value measured by a sensor 18 a valve 19 in pipe 17 is closed so that the second tank member is locked in its upper most position. The air in the tank may thus be retained in a compressed state, with suitable valving to control the air flow from the connections 11,12 until it is desired to use it irrespective of the state of the tide. In an alternative mode of operation, a partial vacuum is created when the outer lank member 8 sinks as the tide falls, and the vacuum sensed by the sensor 18 is caused to close the valve 19 to lock the tank members 6,8 to store the vacuum for subsequent use. WHAT I CLAIM IS:-

1. An apparatus for deriving power from a rise or fall in the level of a body of liquid comprising a first tank member which said liquid level moves relative to and a second buoyant tank member which cooperates in a gas tight manner with said first tank member so as to form a gas tight tank within which a gas is compressed or rarefied on the rise or fall of said liquid level such that the compressed gas or partial vacuum may be used as a source of power.

2. An apparatus according to claim 1 wherein the two tank members are annular as seen in plan view and have respective outer cylindrical walls which cooperates slidably and sealingly, the first tank member having a closed upper end and being mounted on a support comprising a support member extending axially through it and the second tank member having a closed lower end slidably and sealingly cooperating with said support member.

3. An apparatus according to claim 2 wherein said outer wall of the second tank member is radially outside the outer wall of said first tank member and is attached to a buoyant collar surrounding it.

4. An apparatus according to any one of claims 1 to 3 further comprising means for preventing relative movement of said first and second tank members so that said compressed gas or partial vacuum may be retained.

5. An apparatus according to claim 4 wherein said means for preventing'relative movement of said tank members comprise a telescopic hydraulic fluid container and a valve controlling fluid flow into and out of the container.

6. An apparatus for deriving power from a rise or fall in the level of a body of liquid substantially as herein described with reference to the accompanying drawings.