GB1587593A

GB1587593A - Apparatus for the utilisation of wave energy

Info

Publication number: GB1587593A
Application number: GB10075/78A
Authority: GB
Original assignee: Olsen J R
Current assignee: Olsen J R
Priority date: 1977-03-28
Filing date: 1978-03-14
Publication date: 1981-04-08
Also published as: FR2385908A1; PT67792A; NO781023L; SE7803392L; ES468256A1; IT7821643A0; IT1093733B

Description

(54) APPARATUS FOR THE UTILIZATION OF WAVE ENERGY (71) I, JENS ROBERT OLSEN, a Subject of the King of Denmark, of Sonderstrandsvej 35, 4400 Kalundborg, Denmark 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: - The present invention relates to an apparatus for the utilization of wave energy and having at least one pontoon moved by the undulations of the water surface.

Known apparatuses of this kind consist in general of a device securely mounted on a lake or ocean floor and a movable pontoon which follows the undulations of the water surface, by these means transferring wave energy to the securely mounted device.

These apparatuses are, however, relatively complicated.

In accordance with the present invention there is provided an apparatus for the utilization of wave energy, comprising an hydraulic circuit through which an hydraulic liquid is pumped by one or more hydraulic piston pumps to operate an electric generator, characterized in that the piston rod of the or each pump is connected to one end of a pivotally mounted lever, while the other end of the lever is connected to a respective pontoon, said pontoon being movable by the undulations of the water, and in that the hydraulic circuit is supported by a floatable device pivotally mounted on a rod member to be secured substantially vertically in relation to a lake or ocean floor, said device being so inert as regards floatability that it can only follow the average changes in the water level.

Preferably a plurality of pontoons are utilized.

As a result, an apparatus of relatively simple construction is achieved which is at all times able to adjust to changes in the water level and to changes in the direction of the waves, due to the fact that the device to which wave energy is transferred is floatable, pivotable and displaceable. By using a closed hydraulic system for transferring the wave energy to the generator, greater durability is ensured in the apparatus, as the inner parts of the apparatus are not exposed to the corrosive effect of sea water, and the advantages of using hydraulic liquid for transferring energy are exploited.

In addition an apparatus is achieved which at all times ensures a relatively good exploitation of wave energy and which is of relatively simple construction. This is especially due to the fact that the device supporting the hydraulic circuit and the pontoons is able to adjust to the direction of the waves. Thus the pontoons will at times be passed by the greatest number of waves possible per unit of time, and the forces that the pontoons will be exposed to will therefore be directed substantially along the length of the levers. By following the rise and fall of the water level, the pontoons and the levers are always situated in the best possible relationship to the piston pumps regardless of the water level.

According to the invention the rod member may furthermore be adapted to be driven into the lake or ocean floor, thereby ensuring easy mounting of the apparatus.

In the event of heavy ice formation, the device with pumps and pontoons may be relatively easily lifted off the rod member and brought safely ashore.

According to the invention the floatable device may comprise a container with a first and a second closed chamber, each being adapted to contain the hydraulic liquid.

The chambers are connected to the hydraulic pump or pumps and an engine which drives the generator in such a manner that the pump, when the apparatus is in operation, pumps liquid from the first chamber to the second chamber, said liquid being passed back into the first chamber through the engine due to the pressure differential. By these means an especially preferred embodiment of the invention is obtained, which i. a. allows pressure to build up in the second chamber.

Moreover according to the invention the two chambers may be located one over the other inside the container, and the con tainer may comprise at least one lower airfilled chamber, thereby ensuring simple construction of the container. At the same time its floatability is achieved by the presence of the air-filled chamber.

According to the invention the hydraulic piston pumps may be pivotally mounted on an axis perpendicular to a radius of the container and substantially horizontal when the device is mounted; and the levers may be pivotally mounted on an axis parallel to the axis of rotation of the pumps, thereby ensuring simple suspension of the pumps and levers, said suspension being at the same time well suited for resisting the forces affecting the piston pumps along the length of the levers, due to their rotating around their axis of rotation.

Furthermore according to the invention the levers and the hydraulic pumps may be situated symmetrically around a vertical plane containing the axis of rotation of the container. As a result a well-balanced apparatus is achieved which easily adjusts to the direction of the waves, so that the vertical symmetry plane will always extend in this direction.

According to the invention the length of and the space between the levers may also be adapted, so that the pontoons, when viewed away from the symmetry plane are located in the wake of the pontoons nearest the symmetry plane, thereby ensuring the greatest possible exploitation of wave energy.

According to the invention each of the levers may consist of two articulated parts, pivotable in relation to each other around a substantially horizontal axis; between said two parts of each lever there may be hydraulic piston pumps also in communication with the hydraulic circuit, the cylindrical parts of the pumps being pivotally connected to one part of the lever and the piston rod of the pumps being pivotally connevted to the other. By these means the apparatus can effectively exploit the backward and forward undulations in the travel direction of the waves.

The present invention will be described below with reference to the accompanying drawing, in which fig. 1 is a diagrammatic plan view of a preferred embodiment of an apparatus according to the invention, fig. 2 is a diagrammatic view of the apparatus shown in fig. 1, seen in cross-section along line II-II, and fig. 3 is a diagrammatic view of another embodiment of the invention, seen in a cross-section identical to the one shown in fig. 2.

The apparatus according to the invention illustrated in fig. 1 and fig. 2 comprises a floatable, hollow, cylindrical container having a co-axial, through opening for receiving a rod member 3, on which the container 2 is mountable, so that it can slide freely along its axis and pivot freely around its axis. The lower end of the rod member is pointed as shown in fig. 2, so that it can be easily driven into the lake or ocean floor in a substantially vertical position. As shown in fig. 2, the cylindrical container comprises a first chamber 4, above it a second chamber 5 and below it a third chamber 6. The first and the second chambers are adapted to contain an hydraulic liquid 7, whereas the third chamber 6 is filled with air to ensure the floating of the container above water.

Extending through the tank wall at the bottom of the first chamber is a pipe 8, which is in communication with the suction side of several hydraulic piston pumps 1 la, lib . . . llf . . . llj through a first branch pipe 9, the discharge side of the pumps being in communication with a second branch pipe 13, from which a pipe 14 extends through the container wall into the second chamber 5.

As shown in fig. 1 the row of piston pumps is aligned symmetrically on both sides of a vertical plane containing the common axis of the rod member 3 and the container 1. Each piston pump is pivotally mounted on a common bracket part 15, so that they have a common axis of rotation.

The connection between the branch pipe 9, which is in communication with the first chamber in the container, and each piston pump comprises a resilient pipe section lOf and a check valve 16f connected hereto (see especially fig. 2). In the same way, the connection between the second branch pipe 13, which is in communication with the second container chamber 5, and the discharge side of each piston pump comprises a resilient pipe section 12f and a check valve 17f connected hereto. The bracket part 15, on which the piston pumps are pivotally mounted is secured to the exterior of the container wall.

The piston rod 18a . 18f . . 18i of each pump is pivotally connected to one end of its respective lever 19a . . . 19f . . . 19j, the other end of the lever being connected to a pontoon 20a . . . 20f . . . 20j, which is adapted so as to be moved by the undulations of the water surface. All levers 19a l9j are pivotally mounted on a common rod 21 so that they can pivot around an axis parallel to the common axis of rotation of the pumps. The common rod 21 is secured to the exterior of the container wall by means of two bracket arms 22 and 23.

As shown in fig. 2 especially, the container has a pipe 26 extending from the second chamber through the container wall into the inlet side of an hydraulic engine 24 which is used to operate an electric generator 25. A pipe 27 extends from the outlet side of the hydraulic engine 24 along the side of the container and through the container wall into the first chamber 4.

Furthermore between the floor of the second chamber 5 and the first chamber 4 is a by-pass pipe 28 with a suitable safety valve 29.

When the rod member has been driven into the lake or ocean floor, preferably away from the surf in the case of the lat ter, and the container 1 with pumps and pontoons has been placed onto the rod member, the container will float above water and the pontoons will follow the undulations of the waves, as indicated by the arrow 30 in fig. 2, in which the water surface is represented by a chain dotted line. By giving the container a certain weight, said container will not follow the undulations of the waves, but will move only with the rise and fall of the water level. When the apparatus according to the invention is in operation, the movement of the pontoons represented by arrow 30 is, as indicated by arrow 31 in fig. 2, transferred to their respective piston pumps.By these means the piston pumps draw hydraulic liquid from the first chamber through the pipe 8, the branch pipe 9, the pipe sections 10f and the check valve 16f into the pump cylinder.

From there the hydraulic liquid is pressed out through the check valve 17f, the pipe sections 12f, the branch pipe 13 and the pipe 14 and down into the second chamber 5 of the container. As the chambers of the container are closed, pressure will build up inside the second chamber 5 which will consequently function as a pressure source supplying hydraulic liquid through pipe 26 to operate the hydraulic engine 24. The hydraulic liquid flows from the hydraulic engine 24 back into the first chamber through pipe 27. To ensure that a suitable volume flow is constantly supplied to the hydraulic engine, a suitable control means may be inserted between the second chamber 5 and the hydraulic engine in communication with pipe 26.In the event that the pressure inside the second chamber reaches too high a level, the safety valve 29 and the by-pass pipe 28 ensure that the hydraulic liquid is channeled back to the first chamber 4, by-passing the hydraulic engine.

As illustrated in fig. 1, the levers increase in length, the longest ones being farthest from the aforesaid symmetry plane containing the axis of the rod member 3. In a preferred embodiment of the invention, the length of the two outermost levers 19a and l9j is such that the centres of gravity of their respective pontoons are on a line perpendicular to the symmetry plane, which line lies a predetermined distance from a corresponding line through the centre of gravity of the two pontoons 20e and 20f closest to the symmetry plane. This dis tance may correspond to the normal wave length in the area in which the apparatus is to be used. The lengths of the other levers increase gradually as illustrated from the innermost to the outermost levers.In a preferred embodiment of the invention the distance of the individual pontoons from the aforesaid symmetry plane is adjusted, so that their centres of gravity are located in the wake of the innermost pontoons during a normal wave.

Also, as shown in fig. 1, the diameters of the piston pumps increase in size, the largest ones being farthest from the aforesaid symmetry plane, as the diameter together with the stroke of the individual piston pump is adjusted according to the lengths of the levers, so that each pump supplies the same amount of liquid per pump stroke.

The embodiment of the invention shown is constructed so that the apparatus as a whole will not be conspicuous above water.

The individual parts of the apparatus are made of suitable, corrosion-resistant material.

The invention has been described with reference to a special embodiment. Many modifications may be made, however, without departing from the scope of the invention. For example, the number of piston pumps and pontoons may be different, or the length of the individual levers may be changed. Furthermore the piston pumps may be located differently in relation to the container, so that they become even less conspicuous above water.

The rod member 3 may be made of steel.

The lever arms l9a . . . 19f . . 19j may be made of aluminium, for example, or another strong, yet lightweight material. The pontoons 20a . . 20f . . . 20j may be made of fiberglass re-inforced plastic.

Fig. 3 is another embodiment of the apparatus according to the invention which is well suited for the utilization of wave energy in both vertical and horizontal direction. Besides the construction parts shown in fig. 1 and fig. 2, the apparatus here has lever parts consisting of two articulated parts 31, 21f, together forming a suitable angle, said parts rotating freely in relation to each other around a horizontal axis.

The two lever parts are connected by means of an hydraulic piston pump 33f in such a manner that the pump cylinder 36f is pivotally joined to one lever part 31f, whereas the piston rod 37f is pivotally joined to the other lever part 32f. Like piston pumps ilk . . . llf . . . llj, the suction side of each piston pump 33a . . 33b . . . 33j is con nected to the first branch pipe 9 and the discharge side of each piston pump 33a 33f . . 33j is connected to the other branch pipe 13 through suitable resilient conduits 34a . 34f . . 34j and 35a . . 35!. . 35j respectively. In order to make room for the piston pump located between the two parts of a single lever, the second part 32f has an elbow adjacent to the connection with the bracket arm 23.When the apparatus shown in fig. 3 is in operation, it is possible to utilize the force of the waves, so that their horizontal undulations cause a movement of the first parts 31a . . . 31j of the levers in the direction indicated by the arrow 38, thereby achieving a relative movement of the two lever parts and an activation of the hydraulic pumps 33.

Whercas the pump and suction strokes of the pumps located on the cylindrical con tainer 1 ai.e e both automatically achieved by means of wave undulations, the waves only contribute to one kind of stroke in the pumps located between the lever parts.

The other kind of stroke may be achieved by means of a spring mechanism adapted to bring tlie piston rods back towards the bottom of the cylinder.

WHAT I CLAIM IS: 1. An apparatus for the utilization of wave energy, comprising an hydraulic circuit through which an hydraulic liquid is pumped by one or more hydraulic piston pumps to operate an electric generator, characterized in that the piston rod cf the or each pump is connected to one end of a pivotally mounted lever, while the other end of the lever is connected to a respective pontoon, said pontoon being movable by the undulations of the water, and in that the hydraulic circuit is supported by a floatable device pivotally mounted on a rod member to be secured substantially vertically in relation to a lake or ocean floor, said device being so inert as regards floatability that it can only follow the average changes in the water level.

2. An apparatus as claimed in claim 1, characterised in that the floatable device comprises a container with a first chamber and a second chamber, each being adapted to contain the hydraulic liquid, said chambers being connected to the hydraulic piston pump or pumps and an engine which drives the generator, so that said pump or pumps. when said apparatus is in operation, pump liquid from the first chamber to the second chamber, said liquid being passed back into the first chamber through the engine due to the pressure differential 3. An apparatus as claimed in claim 2, characterised in that the container is cylindrical and the rod member extends coaxially through the container.

4. An apparatus as claimed in claim 3, characterised in that the rod member is adapted so as to be driven into the lake or ocean floor.

5. An apparatus as claimed in claims 3 or 4, characterised in that the piston pump or pumps are located outside the container.

6. An apparatus as claimed in claims 3, 4 or 5, characterised in that the two chambers are located one above the other inside the container and the lowest chamber of the container is air-filled.

7. An apparatus as claimed in claim 5 or 6, characterised in that the hydraulic piston pump or pumps are pivotally mounted on an axis perpendicular to a radius of the container, said axis being substantially horizontal when said apparatus is mounted, and said lever or levers being pivotally mounted on an axis parallel to the axis of rotation.

8. An apparatus as claimed in claim 7, characterised in that the suction sides and the discharge sides of the hydraulic pump or pumps are connected to their respective branch pipes, said branch pipes extending parallel to the axis of rotation of the pump or pumps and being in communication with the first and second chambers respectively.

9. An apparatus as claimed in one or more of claims 3-8, characterised in that the lever or levers together with the hydraulic pump or pumps are situated symmetrically around a vertical plane containing the axis of rotation of the container.

10. An apparatus as claimed in claim 9, characterised in that, where a plurality of pontoons are utilized, the levers increase in length viewed away from the symmetry plane.

Il. An apparatus as claimed in claim 10, characterised in that the length of the levers is adjusted to the normal wave length of the area in which said apparatus is being used, so that the centre of gravity of the outermost pontoons lies on a line perpendicular to the symmetry plane, said perpendicular line being a normal wave through the centres of gravity of the pontoons located nearest the symmetry plant.

12. An apparatus as claimed in claims 10 or 11, characterised in that the length of and space between the levers are adjusted so that the pontoons, when viewed away from the symmetry plane, are located in the wake of the pontoons nearest the symmetry plane.

13. An apparatus as claimed in claims 10, 11, or 12, characterised in that the length of stroke and the diameter of the piston pumps are adjusted to the length of the levers and the location of the pontoons, so that each pump supplies substantially the same amount of hydraulic liquid at each stroke.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. nected to the first branch pipe 9 and the discharge side of each piston pump 33a 33f . . 33j is connected to the other branch pipe 13 through suitable resilient conduits 34a . 34f . . 34j and 35a . . 35!. . 35j respectively. In order to make room for the piston pump located between the two parts of a single lever, the second part 32f has an elbow adjacent to the connection with the bracket arm 23. When the apparatus shown in fig. 3 is in operation, it is possible to utilize the force of the waves, so that their horizontal undulations cause a movement of the first parts 31a .. . 31j of the levers in the direction indicated by the arrow 38, thereby achieving a relative movement of the two lever parts and an activation of the hydraulic pumps 33. Whercas the pump and suction strokes of the pumps located on the cylindrical con tainer 1 ai.e e both automatically achieved by means of wave undulations, the waves only contribute to one kind of stroke in the pumps located between the lever parts. The other kind of stroke may be achieved by means of a spring mechanism adapted to bring tlie piston rods back towards the bottom of the cylinder. WHAT I CLAIM IS:

1. An apparatus for the utilization of wave energy, comprising an hydraulic circuit through which an hydraulic liquid is pumped by one or more hydraulic piston pumps to operate an electric generator, characterized in that the piston rod cf the or each pump is connected to one end of a pivotally mounted lever, while the other end of the lever is connected to a respective pontoon, said pontoon being movable by the undulations of the water, and in that the hydraulic circuit is supported by a floatable device pivotally mounted on a rod member to be secured substantially vertically in relation to a lake or ocean floor, said device being so inert as regards floatability that it can only follow the average changes in the water level.

2. An apparatus as claimed in claim 1, characterised in that the floatable device comprises a container with a first chamber and a second chamber, each being adapted to contain the hydraulic liquid, said chambers being connected to the hydraulic piston pump or pumps and an engine which drives the generator, so that said pump or pumps. when said apparatus is in operation, pump liquid from the first chamber to the second chamber, said liquid being passed back into the first chamber through the engine due to the pressure differential

3. An apparatus as claimed in claim 2, characterised in that the container is cylindrical and the rod member extends coaxially through the container.

14. An apparatus as claimed in one or

more of claims 1-13 characterised in that the or each of the levers consists of two articulated parts which are relatively pivotable around a substantially horizontal axis, and in that an hydraulic pump, also in communication with the hydraulic circuit, is located between the two parts of the or each lever, the cylindrical part of said piston pump being pivotally joined to the first lever part and the piston rod of said pump being pivotally joined to the other lever part.

15. An apparatus as claimed in claim 14, characterised in that the suction and discharge sides of the hydraulic pump or pumps are connected to their respective one of the two branch pipes through suitable conduits.

16. An apparatus for the utilization of wave energy substantially as described with reference to and as shown in the accompanying drawings.