METHOD AND DEVICE FOR CONVERTING WAVE ENERGY

Abstract: Method and device for converting energy into a form of energy which can be used in practice. The device comprises an elongated body (4) which is provided along the periphery with longitudinal vanes (2), disposed at angles to the radial direction, at least at their outer portions. The vanes define chambers which are bounded axially by walls (3) along the periphery of the body, which are disposed at angles to the vanes. The vanes afford a greater displacing capacity at one side of the longitudinal axis of the body than at the other side so that the body is caused to rotate by wave movements when it is anchored in the water with the longitudinal axis substantially in the surface of the water.

Description: METHOD AND DEVICE FOR CONVERTING WAVE ENERGY The present invention relates to a method and a device for converting wave energy into a form of energy that can be used in practice, particularly for convert¬ ing wave movement into a rotational movement. Man has long tried to make use of the energy which is found in waves on seas and lakes and in doing so has most often tried to utilize floating bodies which are firmly anchored to the bottom of the sea or lake, or floating bodies, the mass inertia of which is utilized to convert the wave energy into another form of energy which can be used. However, the majority of attempts which have hitherto been made to convert wave energy into a form of energy ' which can be used have involved several disadvantages: the constructions have been complicated and expensive, and the possibility of effectively converting the wave energy has been li ited. The object of the invention is to render possible the effective conversion of the wave energy into another form of energy by means of a device which is of extremely simple and robust construction. The object of the invention is achieved by a method of converting wave energy into a form of energy which can be used in practice, with the features which appear from claim 1. In-order to carry out this method, the invention also provides a device for converting wave energy into a form of energy which can be used in practice, compris¬ ing an elongated, preferably cylindrical body which is provided along the periphery with longitudinal vanes, this device having obtained the features according to claim 3. The invention will be explained in more detail with reference to an illustrative embodiment which is shown on the accompanying drawing in which FIG. 1 is a side view of a device according to the invention, anchored floating on the surface of a sea or lake, FIG. 2 is a side view of part of the device in FIG. 1 , and FIG. 3 is an end view of the device in FIG. 1 , FIGS. 2 and 3 being shown on a larger scale. In FIG. 1 the device for carrying out the method according to the invention is designated generally by reference 1 and is shown floating on the surface of a sea or a lake where waves occur. The device is anchored by means of the bottom footings A and B and ropes a and b connected thereto, with the longitudinal axis sub¬ stantially in the surface of the water and at an angle to the prevailing direction of the wave fronts. As a result, the mooring forces are small while at the same time the device tends to adjust itself in a favourable working position in relation to the direction of the waves. It may suffice to provide an anchoring device at one end only and not at both ends as shown here. The device 1 comprises a cylindrical body 4 with vanes 2 which extend axially along the body and project therefrom at an angle to the radial direction, the outer portions of the vanes being bent at an angle. The vanes may, however, also be arranged flat and/or curved. They can also be arranged with a pitch along the outer sur¬ face ' of the body, which is particularly advantageous if the device according to the invention is intended to work in breaking waves, since a device constructed in this manner permits conversion of some of the "horizontal" kinetic energy of the wave into rotational movement. Partitions 3 are arranged radially and extend peripherally round the body axially spaced. They may, OMPI . W WIIPPΌO in the speed of rotation. The reaction forces during the rotation of the device can be taken up by a floating platform anchored stationary or by a construction fixed to the bottom. The stator of an electrical generator is then disposed on the platform or the construction fixed to the bottom, while its rotor is connected to the rotating body. It is also possible to connect two bodies adapted to rotate in opposite directions. In such a case, the stator of the generator is connected to the one body and its rotor to the other body. Holes 5 may be provided in the vanes 2, as shown in FIG. 3, through which air can .pass in under the vanes at the side 2a when the device moves upwards. As a result of the fact that air passes in through the vanes, these release more easily the water which is present at the ' bottom side of the vanes. Otherwise, this water can exert a braking force on the rotating device. Water, however, does not pass through the holes 5 as easily as air and in this manner the openings act as non-return valves. Nevertheless, the openings 5 may also be provided with valve bodies which are open in the upward-moving part of the device but which close when they come into the downward-moving part 2b, FIG. 3, of the device. These valve bodies may consist of some form of flap. The device according to the present invention thus consists of a simple movable body to which an electric generator, for example, can be connected directly or through a simple transmission. The device can be given an uncomplicated shape, which provides a simple and sturdy construction with great stiffness, suitable for the manufacture of large series from cheap material . The device according to the invention can also be de- signed so that it can stand up to storms and even is able to take up energy from storm waves. It may be added that the device can be mounted in a construction fixed to the bottom with the longitudinal axis of the body . substanti al ly in the surface of the water. Thus, the body does not necess¬ arily have to be a floating body. Nor does it need to be a body of revolution but may have a polygonal shape

Claims: CLAIMS 1. A method of converting wave energy into a form of energy which can be used in practice, c h a r a c ¬ t e r i z e d in that an elongated body with longi¬ tudinal vanes which afford a greater displacing capacity at one side of the longitudinal axis of the body than at the other side, is anchored in the water with the longitudinal axis substantially in the surface of the water (FIG. 1). 2. A method as claimed in claim 1 , c h a r a c - t e r i z e d in that the body is disposed with its longitudinal axis at angles to the prevailing direction of the wave fronts. 3. A device for converting wave energy into a form of energy which can be used in practice by carrying out the method as claimed in claim 1 , comprising an elongated, preferably cylindrical body (4) which is provided along the periphery with longitudinal vanes (2), c h a r a c t e r i z e d in that the vanes (2) are disposed at angles to the radial direction, at least in their outer portions, to define chambers between the vanes with a greater displacing capacity at one side of the longitudinal axis of the body than at the other side of the longitudinal axis and that these chambers are bounded axially by walls (3) along the periphery of the body, which are disposed at angles to the vanes. 4. A device as claimed in claim 3, c h a r a c ¬ t e r z e d in that the vanes are disposed with a pitch along the outer surface of the body (4). 5. A device as claimed in claim 3 or 4, c h a r a c t e r i z e d in that the body (4) is adapted as a floating body. 6. A device as claimed in one of the claims 3 to 5, c h a r a c t e r i z e d in that the length of the device (1) exceeds the length of the waves. 7. A device as claimed in one of the claims 3 to 6, c h a r a c t e r i z e d in that air openings (5) are provided in the vanes (2). 8. A device as claimed in claim 7, c h a r a c ■ t e r i z e d in that the air openings are provided with non-return valves adapted to open in the upward- - oving part of the body to admit air under the blades ___ OMPf

Inventors: WINCRANTZ F
Applicants: WINCRANTZ F
Application year: 1981
Main classification: F03B13
IPC codes: F03B13