GB1601398A

GB1601398A - Method and installation for generating power from the buoyancy of water

Info

Publication number: GB1601398A
Application number: GB15257/78A
Authority: GB
Original assignee: FERNEZ A
Current assignee: FERNEZ A
Priority date: 1977-04-20
Filing date: 1978-04-18
Publication date: 1981-10-28
Also published as: BE866192A; NL7804105A; IT1094463B; FR2388143B1; FR2388143A1; DE2817077A1; LU77162A1; IT7822560A0

Description

(54) METHOD AND INSTALLATION FOR GENERATING POWER FROM THE BUOYANCY OF WATER (71) I, ADOPHE FERNEZ, a subject of the King of the Belgians, of Braine-le-Comte (Belgium), 190, Chemin de Feluy, 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 performed, to be particularly described in and by the following statement:- This invention relates to a method for generating power from the buoyancy of water by using a water level differential and more particularly, the invention is intended to work with relatively low water level differentials, which are for example comprised between about 1 and 5 m.

It is to be noted that level differentials in this range are to be found frequently on plain rivers or along sea coasts where the tide phenomenon is marked.

Such water level differentials could not be worked efficiently up to now for generating power due to the low output from the hydraulic apparatus for collecting power under such conditions.

Consequently an object of the invention is to provide a simple, inexpensive and efficient method for generating power from a relatively low water level differential.

This object and other objects are obtained according to to one aspect of the invention by a method for generating power from the buoyancy of water in which power is generated according to a cycle which comprises floating a closed and substantially empty tank in a body of water between an upper and a lower level opening said tank to said body of water to permit water to enter the tank so that the tank sinks to an intermediate level, locking said tank at said intermediate level, reclosing said tank to isolate the water in the tank from the body of water lowering the level of the body of water and unlocking the tank to permit the tank containing the isolated water to fall down under the action of gravity while collecting power thus generated, discharging the tank water to the lower level and raising the empty tank by the action of the Archimedian thrust caused by recreating the body of water utilising water from the upper level, up to the original tank position, while collecting power thus generated, so as to start the cycle over again.

According to a further aspect the invention provides a method for generating power from the buoyancy of water in which power is generated according to a cycle which comprises successively isolating in a basin a certain quantity of water on an upper level of two water levels floating a closed and substantially empty tank in said basin on said upper water level of this isolated quantity, opening said tank to permit water from said basin to enter the tank so that the tank sinks to an intermediate level locking said tank at said intermediate level, reclosing the tank to isolate the water in the tank from the water in the basin, lowering the level of the water in the basin under this intermediate level, and unlocking the tank so that said tank containing the isolated water falls down under the action of gravity, while collecting power thus generated, discharging the tank water to said lower level and then raising the tank by the action of the Archimedian thrust caused by water from the upper level introduced in said basin up to the original tank position referred to hereinabove, while collecting power thus generated, so as to start the cycle over again.

Another object of the invention is to provide an installation for the working of the method of the invention.

The installation for the working of the method according to the invention comprises a dam for forming two different water levels, a basin downstream from the dam said basin having means for causing same to communicate at will with the upper water level to permit water to flow into the basin or with the lower level to permit water in the basin to drain to the lower level, a closed and substantially empty tank disposed in the basin so as to be capable of floating in water in the basin and movement in a vertical direction between an upper and a lower position, inlet and outlet openings in said tank for permitting respectively water from the basin to enter the tank and water to empty from the tank a closure member for each said tank opening and releasable locking means for locking said tank in an intermediate position between said upper and lower positions.

Other details and features of the invention will stand out from the following description given by way of non limitative example and with reference to the accompanying drawings, in which: Figure 1 shows diagrammatically the various steps in a power-generating cycle according to the invention.

Figure 2 is a diagram in which the working force acting on the tank is plotted along the X-axis and the vertical position of the tank bottom relative to the lower water level being plotted along the Y-axis.

Figure 3 is a view showing in cross-section an embodiment of the invention.

Figure 4 is a view showing in cross-section another embodiment of the invention.

The invention provides for the use of a tank I which is movable vertically relative to a basin 2 downstream from a dam dividing two discrete water levels: an upper level 3 and a lower level 4.

By means of suitable closing and opening members, the basin 2 can be caused to communicate at will with the upper water level by means of members 5 such as a socalled upper-basin gate, or with the lower water level by means of members 6, such as a so-called lower-basin gate. The tank 1 can also communicate at will with basin 2 by means of a closing and opening member 7, such as a so-called tank-basin gate. By the term "at will", there should be understood that the closing and opening of said members occurs at predetermined times which are a function of the position of tank 1.

With reference to figures I and 2 there will now be described a preferred cycle for generating power according to the invention.

In figure 2 has been shown diagrammatically the main cycle the various steps of which have been shown in figure 1. On the X-axis in figure 2 has been plotted the working force F acting on tank 1 along a vertical direction and when considering as positive direction the direction of the gravity force. The working force F is equal to the sum of the weight of tank 1 together with the contents thereof and of the Archimedean thrust said tank undergoes. On the Y-axis is plotted the height at which lies the tank bottom relative to the lower water level.

At the beginning of the cycle, that is during a step I, the tank 1 swims on the water retained in basin 2 which is filled up to the same level as the upper water level 3 and the members 5 and 6 stand in the closing position. Said step I corresponds to point 8 in figure 2. During a step II, the tank is set in communication with basin 2 by opening member 7 and water enters said tank 1 while the tank sinks into the basin 2 filled with water. During a step III the tank 1 is locked into an intermediate position and it is isolated from basin 2 by closing member 7. The steps II and III correspond in figure 2 to the passage from point 8 to point 9 along a clockwise direction. During a step IV, the basin 2 is caused to communicate with the lower water level 4 by opening member 6 so as to drain same from the water thereof.Said step IV corresponds to the passage from point 9 to point 10 in figure 2. As soon as said step IV is ended the tank 1 filled with water is unlocked to let same go down under the action of gravity, towards the basin bottom, down to the lower level. This comprises a step V corresponding in figure 2 to the passage from point 10 to point 11, which performs a first power stroke, the driving force acting along the direction of arrow A and it is used for generating power. During a step VI. the tank I is caused to communicate by opening member 7, with the empty basin 2 which still communicates with lower lever 4 so as to drain the water contained inside tank 1 towards said lower level.After emptying during a step VII, the tank I is locked in a position at the bottom of the basin, the members 6 and 7 are closed and then during a step VIII, the member 5 is opened to fill that volume of basin 2 which is not taken by tank 1. Said latter steps VI, VII and VIII correspond in figure 2, to the passage from point 11 to point 12. During a step IX, when the water level inside basin 2 is the same as upper level 3, the tank 1 is unlocked, said tank rising under Archimedean thrust while basin 2 goes on filling with water. Said step IX which corresponds in figure 2 to the passage from point 12 to point 8, comprises a second power stroke, the driving force acting along the direction of arrow B and it is used to generate power.When the tank 1 has reached the original position thereof, corresponding in figure 2 to point 8, it swims on the water contained in basin 2 and during a step X, the member 5 is so closed as to have the tank 1 ready to start the cycle over again.

By way of variation not shown, it is possible not to lock tank 1 after same has been emptied during step VII, but rather to isolate the tank and to go on with the cycle by bringing basin 2 in communication with the upper water level. The basin 2 fills up and the Archimedean thrust which is exerted on tank 1 causes same to rise. The bottom of tank 1 does not lie however at the same level as the water contained in basin 2 but remains partly sunk into the water which fills basin 2 in such a way that the archimedean thrust exerted on tank 1 be equal to the own weight of tank 1 increased by the opposing force exerted thereon by the devices used to collect the generated power.When the tank has stopped and basin 2 has filled up to the upper water level 3, the conditions are back to the original position of the described main cycle and the cycle can start over again.

The overall efficiency of the method can be substantially increased if said intermediate level for the tank bottom lies at half the height of the water level differential. This results more particularly from the diagram as shown in figure 2.

The installation shown in figure 3 or figure 4, comprises a dam 13, downstream of which is arranged a basin 2 the bottom of which does not lie higher than the lower water level 4. The side walls of basin 2 extend at least up to the upper water level 3. Suitable members comprised for example of controlled gates 5 and 6, allow to bring basin 2 in communication respectively with the water at upper level 3 or with the water at lower level 4. Said gates can be arranged one above the other as shown in Figure 3 or on the same level at the bottom of basin 2 as shown in Figure 4. Said tank 1 is so arranged inside basin 2 as to be movable vertically and the side walls thereof have at least a height equal to the water level differential.The tank 1 has advantageously the same shape in horizontal cross-section as basin 2 and it is so adjusted inside said basin 2 that the water can flow without hindrance between the side walls of tank 1 and basin 2 which may however engage slidingly in some points at least, for example through rails not shown, so as to guide tank 1 during the vertical motions thereof. Said tank 1 comprises members, having for instance a controlled gate 7, a so-called tank-basin gate, which let tank 1 communicate with basin 2 through the tank bottom. The tank 1 can be made from concrete or some other suitable material.

In a preferred embodiment of the invention, tank 1 is connected through a rod 14 to a piston 15 which slides inside a doubleaction cylinder 16 to recover the power generated by the fall or rise of the tank. The rod 14 also enables supporting the tank during the various steps of the power generating cycle. The chambers 17 and 18 on either side of the piston 15 are each connected to a first pipe 19 feeding oil and to a second pipe 20 receiving pressure oil which has been pressurized by piston 15. The pressurized oil obtained in pipe 20 during the fall or rise of tank 1 may then be used thereafter to drive for example electricity generators and after being used, said oil is fed back to cylinder 16 through pipe 19. The locking of tank I to secure same in position during steps IV and VIII may advantageously be obtained by closing valves 21 and 22 in the oil circuit as shown in figure 3.

It is clear that a plurality of cylinders may easily be used instead of a single cylinder, said cylinders then being connected through a plurality of rods to tank 1 so as to better support and guide same as well as to allow a better weight distribution.

As regards the use of the power generated during the motions of tank 1, the man of the art might easily design other arrangements than the one described above, particularly by making use of rack, crank or hydropheumatic systems.

When the water throughput available between both levels is larger than the operating capacity of an installation with a single tank 1 the size of which is of course limited by building and strength considerations, it is possible to have an arrangement in which a plurality of installations according to the invention each having a tank, are connected im parallel relationship. Such an arrangement has the advantage that the motions of the tanks can be out-of-phase in such a way that the various steps of the generating cycle are not repeated at the same time for each tank and thus the power strokes of different tanks follow one another so as to collect continuously or substantially continuously power from the installation.

Members could possibly be provided to store the power generated during the power strokes so as to return same during those cycle steps where no power is generated.

Such members could for example comprise a fly-wheel.

The above-described installation can be erected in a suitable location on a stream where there is a high enough water level differential, for example where a lock is provided. The installation could also be erected on a sea coast where the tide motion is marked and which allows building a dam to separate the sea from an inner catch basin.

The installation would operate both at high tide when the. sea water will flow into the catch basin after generating power by passing through the installation, and at low tide when the water retained at high tide inside the catch basin, will flow into the sea after generating power by passing through the installation.

It must be understood that the invention is in no way limited to the above embodiments and that many changes could be brought therein without departing from the scope of the invention as defined by the appended

Claims

claims. WHAT I CLAIM IS:

1. Method for generating power from the buoyancy of water in which power is generated according to a cycle which comprises floating a closed and substantially empty tank in a body of water between an upper and a lower level opening said tank to said body of water to permit water to enter the tank so that the tank sinks to an intermediate level, locking the tank at said intermediate level, reclosing said tank to isolate the water in the tank from the body of water lowering the level of the body of water and unlocking the tank to permit the tank containing the isolated water to fall down under the action of gravity while collecting power thus generated, and discharging the tank water to the lower level and raising the empty tank by the action of the Archimedian thrust caused by recreating the body of water utilising water from the upper level, up to the original tank position, while collecting power thus generated, so as to start the cycle over again.

2. Method for generating power from the buoyancy of water in which power is generated according to a cycle which comprises successively isolating in a basin a certain quantity of water on an upper level of two water levels floating a closed and substantially empty tank in said basin on said upper water level of this isolated quantity, opening said tank to permit water from said basin to enter the tank so that the tank sinks to an intermediate level, locking said tank at said intermediate level, reclosing the tank to isolate the water in the tank from the water in the basin, lowering the level of the water in the basin under this intermediate level, and unlocking the tank so that said tank containing the isolated water falls down under the action of gravity, while collecting power thus generated, discharging the tank water to said lower lever and then raising the tank by the action of the Archimedian thrust caused by water from the upper level introduced in said basin up to the original tank position referred to hereinabove, while collecting power thus generated, so as to start the cycle over again.

3. Method as claimed in Claim 2 in which, after having discharged the tank water to the lower level, said tank is retained near the bottom of the basin while introducing water in the latter from the upper level and while avoiding the introduction of water in the tank, the latter being liberated when the water introduced in the basin has reached about said upper level, so that the tank will raise very quickly by the action of the Archimedian thrust caused by the water from the upper level introduced in said basin.

4. Method as claimed in Claim 1, 2 or 3 wherein the tank bottom is maintained at an intermediate level that lies substantially half way between the upper and lower levels before letting said tank fall down under the action of gravity.

5. Method as claimed in any one of the preceding claims, wherein the power is collected by submitting to a pressure a fluid during the fall and rise of the tank.

6. Method as claimed in Claim 5, in which oil is used as fluid.

7. Installation for the working of the method claimed in any one of the preceding claims comprising a dam for forming two different water levels, a basin downstream from the dam said basin having means for causing same to communicate at will with the upper water level to permit water to flow into the basin or with the lower level to permit water in the basin to drain to the lower level, a closed and substantially empty tank disposed in the basin so as to be capable of floating in water in the basin and movement in a vertical direction between an upper and a lower position, inlet and outlet openings in said tank for permitting respectively water from the basin to enter the tank and water to empty from the tank a closure member for each said tank opening and releasable locking means for locking said tank in an intermediate position between said upper and lower positions.

8. Installation as claimed in Claim 7, wherein the tank inlet and outlet closure members each comprise a controlled gate, a so-called tank-basin gate, the means for letting the basin communicate with the upper water level comprising a controlled gate, a so-called upper basin gate, and the means letting the basin communicate with the lower water level comprising a controlled gate, a so-called lower-basin gate.

9. Installation as claimed in Claim 8, wherein the controlled gates are controlled by a device which allows opening the tankbasin gate when the tank goes down to the intermediate level so as to fill said tank with water, then closing said tank-basin gate and opening the lower-basin gate to empty the basin, opening after the fall of the tank down to the lower level, the tank-basin gate to empty the tank and then closing said gate as well as the lower-basin gate, then opening the upper-basin gate to fill with water that basin portion not taken up by the tank and after the tank rise, closing said upper-basin gate to start the cycle over again.

10. Installation as claimed in any one of Claims 7 to 9, wherein the tank is guided along the basin side walls.

11. Installation as claimed in any one of Claims 7 to 10, wherein the basin bottom lies lower than the lower water level.

12. Installation as claimed in any one of Claims 7 to 11, wherein the height of the tank side walls is at least equal to the water level differential.

13. Installation as claimed in any one of Claims 7 to 12 in which the movable tank is made from concrete.

14. Installation as claimed in any one of Claims 7 to 13, wherein the movable tank is connected to a piston sliding inside a cylinder to submit to a pressure a fluid, the pressure energy of which is recovered during the expansion thereof.

15. Installation as claimed in Claim 14, wherein the cylinder is a double-action type to submit to a pressure the fluid both during the fall and the rise of said tank.

16. Arrangement for generating power, which comprises a plurality of installations as claimed in any one of Claims 7 to 15 operating in parallel relationship.

17. Arrangement as defined in Claim 16, wherein the cycles of the various installations which are part of the arrangement are out-ofphase.

18. Installation as claimed in Claim 7, which is erected on a water stream, said water level differential being obtained by means of a dam.

19. Installation as claimed in Claim 7, which is so erected on a sea coast as to form a catch basin, the water lever differential obtained due to the tide phenomenon, being the differential between the sea level and the water level inside the basin.

20. Arrangement as claimed in Claim 16, which is erected on a water stream, said water level differential being obtained by means of a dam.

21. Arrangement as claimed in Claim 16, which is so erected on a sea coast as to form a catch basin, the water level differential obtained due to the tide phenomenon, being the differential between the sea level and the water level inside the basin.

22. Hydraulic method for generating power, as described above with reference to the accompanying drawings.

23. Hydraulic installation or arrangement for generating power, as described above with reference to the accompanying drawings.