APPARATUS FOR RECOVERING THE INHERENT KINETIC ENERGY FROM WAVES

Abstract: An apparatus for recovering the inherent kinetic energy from waves has a plate assembly (1) consisting of a plurality of juxtaposed, spaced-apart circular plates (2) which are mounted at their centres on a horizontal shaft (3) located on the still-water level (4) parallel to the wave front and which are provided at their sides with fins (6) extending from the centre of the plates to the periphery thereof and being so designed that they can be driven by the rotating water particles of the waves in one direction only, being the direction in which the rotating water particles above the still-water level (4) act on the plates (2).

Description: APPARATUS FOR RECOVERING THE INHERENT KINETIC ENERGY FROM WAVES The present invention relates to an apparatus for recovering the inherent kinetic energy from waves in which the water particles rotate in substantially circular-cylindrical paths which pass into new cir- cular-cylindrical paths downwards as counted from the wave crests, so as to have a diameter progressively decreasing with the distance away from the level of the wave crests. According to the invention, the appa¬ ratus comprises a plate assembly consisting of a plu- rality of juxtaposed, spaced-apart substantially cir¬ cular plates or the like which are mounted at their centres on a horizontal shaft located at least approxi¬ mately on the still-water level parallel to the wave front and which are provided at their sides with fins or the like extending from the centre of the plates to the periphery thereof and being so designed that they can be driven by the rotating water particles in one direction only, being the direction in which the rotating water particles above the still-water level act on the plates. By the invention, it has thus become possible, by relatively simple means, to recover substantial portions of the inherent kine¬ tic energy in waves. The invention will be described in more detail hereinbelow with reference to the accompanying drawings which, by way of example, show an embodiment of the apparatus according to the invention and in which: Fig. 1 is side view of the apparatus when in operation. Fig. 2 is a sectional view taken along the line II-II in Fig. 1, and Fig. 3 is a top plan view of the appa ¬ ratus. The apparatus according to the invention comprises a plate assembly 1 consisting of a plurality of spaced- apart, planar circular plates or discs 2 arranged in side-by-side relationship. The plates 2 which are fixedly mounted at their centres on a horizontal shaft 3 located on the still-water level 4 parallel to the wave front and, thus, at right angles to the direction of motion of the waves as illustrated by the arrow 5. The plates 2 are provided at both sides with straight or arcuate fins or the like extending from the centre of the plates to the periphery thereof and being so designed that they can be driven by the rotating water particles in one direction only r being the direction in which the rotating water particles above the still- water level 4 act on the plates 2. Normally, the planar plates 2 should be unperfo- rated since this contributes to making the flow between the plates 2 laminar. In some cases, it may however prove appropriate to design the plates 2 with perfora¬ tions. In an extreme case, the plates 2 may be more or less dispensed with, the fins 6 then in principle forming spokes. As stated in the introduction to this specifica¬ tion, the wave motion consists in water particles moving in circular-cylindrical paths, the uppermost circle, at its highest point, being tangent to a line 7 passing through the wave crests, and at its lowest point tangent to a line 8 passing through the wave troughs. Midway between the lines 7 and 8 r the still- water level 4 is located. If the wave height r i.e. the distance between lines 7 and 8, is H, the circular plates 2 should suitably have a diameter of 2.0 x H. In one embodiment of the invention, the apparatus comprises at least one further plate assembly 9 which is disposed straight underneath the first plate assembly 1, the plates 10 of the plate assembly 9 extending in between the plates 2 of the first plate assembly 1. Also the plates 10 of the assembly 9 should have a diameter of 2.0 x H. The plates 2 and 10 of the two assemblies 1 and 9, respectively, thus suitably have the same radius, i.e. H. In this case, the distance between the shafts 3 and 11 of the plate assemblies 1 and 9, respectively, should be slightly larger than the radius H, suitably 1.25 x H. Normally, the distance between the plates of each plate assembly 1 and 9 should be approximately one third of the radius of the plates, for instance 0.35 x H. It should however be noted that the relative distance between the plates may be slightly varied. As appears from Fig. 3, the plates 2 and 10 of the plate assemblies 1 and 9 are spaced from each other a distance equalling half the distance between the plates of each assembly 1 and 9. Said half distance is approximately equal to H/6. The number of the fins 6 may be varied, but in the illustrated embodiment there are four fins pro¬ vided on each side of the plates 2 and 10. As best appears from Fig. 2, the fins have the cross-sectional shape of a right-angled triangle with one cathetus engaging the plate 2 and the other cathetus 12 project¬ ing straight out from the plate 2, the hypotenuse 13 of the triangle forming an inclined side, the incli- nation suitably being 1:7. This triangle may of course be slightly modified. The cathetus 12 may be varied in size, but should suitably have a length of about 2 cm. The circular-cylindrical paths of the water par- tides will have a diameter progressively decreasing downwards and become of lesser importance in terms of energy recovery down to a depth of 2-3 x the wave height H. Thus, it is justified only in exceptional cases to provide a further, third plate assembly below the two assemblies 1 and 9. If the width of the energy-producing part is B, as indicated in Fig. 3, it is possible by providing inclined side baffles 14 and 15 in the intake zone 16 in front of the energy-producing part with an angu¬ lar change of 1:7 as counted in the direction of motion of the waves, to increase the intake side or intake width 17 for the waves to B + 2 x r, where the length of the intake zone is 7 x r. Thus, the side baffles 14 and 15 converge towards the intake zone 16. An assembly of the width B will then cover a length of B + 2 x r of the wave front. The upper plate assembly 1, having its shaft 3 disposed horizontally on the still-water level 4 parallel to the wave front, is provided with fins 6 with the cathetus 12 projecting at right angles to the plane of the plate and oriented in opposition to the direction of movement of the water particles, i.e. in the anticlockwise direction with respect to Fig. 1, such that the rotating water particles above the still-water level 4 will drive the plates 2 forwards about their shaft 3. The water particles below the still-water level 4 will rotate in a direction contrary to the wave motion, and the fins 6 on the plates 2 located below the still-water level 4 will drive the plates 2 against the direction of the wave motion and, thus, assist in rotating the plates 2 in the same direction as mentioned above. The lower plate assembly 9, having its shaft 11 located at a distance of 1.25 x H below the upper shaft 3 will rotate in the same direction as the upper assembly 1. Between the shafts 3 and 11, the plates 2 and 10 of the two assemblies will overlap each other , such that the distance between the plates is equal to half the distance between the plates 2 and 10 of each shaft 3 and 11. The rotating water particles in the uppermost circular-cylindrical paths of movement will pass in their lower trajectory the upper fins 6 of the lower plate assembly 9 in a direction contrary to that in - which the upper part of the lower plate assembly 9 is moving. Thus, these water particles will not impinge on the short sides 12 of the fins 6 on the upper part of the lower plate assembly 9, but pass in the opposite direction along the flat hypotenuse 13 of the fins 6 so as not to produce any notable frictional resis¬ tance. The lower plate assembly 9 will however take up the force of the rotating water particles in the circular-cylindrical paths which are located further down in the wave and the upper peripheries of which are tangent to or situated below the horizontal still- water level 4. These latter rotating water particles will thus drive the lower plate assembly 9 in the same direction of rotation as the upper plate asssembly 1. The shafts 3 and 11, which are fixedly anchored in the plates 2 and 10, will rotate as the plates 2 and 10 are driven by the water particles yielding power for driving electric generators and producing electric energy. By means of the apparatus according to the inven¬ tion, it is possible to recover the inherent kinetic energy from waves not only in the water surface but as far down as energy is produced by the circular- cylindrical motions of the water particles. The apparatus is so designed that, irrespective of the direction of movement of the rotating water particles, the energy thereof will be recovered by the apparatus. The apparatus is so designed, with the upper plate assembly 1 locate -with its shaft 3 on the still- water level 4 and having a diameter of 2.0 x H, that energy can be recovered from larger waves than where the difference in level between wave crest and wave trough is equal to H. In this case, energy can be recovered from waves having a wave height of 2.0 x H. In larger waves, wave masses above a horizontal line through wave crests of a height of 2.0 x H cannot be utilized. In the wave zone between the still-water level 4, i.e. the level on which the shaft 3 of the upper plate assembly 1 is located, and the level on which the shaft 11" of the lower plate assembly 9 is located, the inherent kinetic energy of the rotating particles will be taken up, owing to the design of the apparatus, whether the direction of movement of the particles coincides with the direction of the waves or is contrary thereto. Thus, with the apparatus here described it is only a very small portion of the inherent kinetic energy of the rotating particles that is not recovered. The fact that the distance between the plates 2 and 10, respectively, has been chosen at approximately 0.35 x H in this case is because if the plates had been mounted closer to each other, the water particles of inherent energy passing in a direction contrary to that of the perpendicularly extending fins 6 would have an excessively increasing speed, giving rise to turbulence and undesirable movements of the water particles, the energy of which it would not be possible to recover by means of the plate assembly rotating in the opposite direction in the zone between the two shafts 3 and 11. The present apparatus for recovering the inherent kinetic energy from waves is usable also in the case of rough waves. From even waves where alternatingly high and low wave crests appear, as in the case of a "choppy" sea, the inherent kinetic energy can be recovered. Where the sea level does not vary to an excessive extent, the apparatus can be fixedly mounted without having to vary with the still-water level. In this case, the shaft 3 of the upper plate assembly 1 should be positioned on a level which does not substantially deviate from the still-water level 4. In those cases where the sea level varies considerably, the apparatus should be movably mounted so that it can be adjusted to the still-water level 4. In such case, the apparatus may be mounted e.g. on floating bodies. In some cases, it may be assumed that the water particles of the inherent kinetic energy do not move in strictly circular-cylindrical paths, but in more or less deformed paths which do not give straight wave fronts but fronts terminated in any other way. it may therefore prove advantageous to set the planar circular plates 2 and 10, respectively, at a slight angle differing from the right angle to the rotary shaft 3 and 11, respectively, as shown in the drawings. The invention is not restricted to the embodiment illustrated above and shown in the drawings, but may be modified within the scope of the accompanying claims.

Claims: CLAIMS 1. Apparatus for recovering the inherent kinetic energy from waves in which the water particles rotate in substantially circular-cylindrical paths which pass into new circular-cylindrical paths downwards as counted from the wave crests, so as to have a dia¬ meter progressively decreasing with the distance away from the level of the wave crests, wherein it comprises a plate assembly (1) consisting of a plurality of juxtaposed, spaced-apart substantially circular plates (2) or the like which are mounted at their centres on a horizontal shaft (3) located at least approximately on the still-water level (4) parallel to the wave front and which are provided at their sides with fins (6) or the like extending from the centre of the plates to the periphery thereof and being so designed that they can be driven by the rotating water particles in one direction only, being the direction in which the rotating water particles above the still-water level (4) act on the plates (2). 2. Apparatus as claimed in claim 1, wherein it comprises at least one further plate assembly (9) disposed below said first plate assembly (1), the plates (10) of said further plate assembly (9) extending in between the plates (2) of the first plate assembly (1). 3. Apparatus as claimed in claim 2, wherein the plates (2, 10) of said first (1) and of said further plate assembly (9) have substantially the same radii (H), the distance between the shafts (3, 11) of the two plate assemblies (1 and 9, respectively) slightly exceeding said radius (H) . 4. Apparatus as claimed in claim 3, wherein the distance between the plates (2, 10) of each plate assembly (1 and 9, respectively) is approximately one third (H/3) of the radius (H) of the plates (2, 10). 5. Apparatus as claimed in claim 4, wherein the plates (2, 10) of the two plate assemblies (1, 9) are spaced from each other a distance equalling half the distance (H/6) between the plates (2 and 10, re¬ spectively) of each assembly (1 and 9, respectively). 6. Apparatus as claimed in any one of claims 1-5, wherein the fins (6) on the sides of the plates (2, 10) have the cross-sectional shape of a right-angled triangle with one cathetus engaging the plate (2 and 10, respectively) and the other cathetus (12) extending straight out from the plate (2 and 10, respectively), the hypotenuse (13) of the triangle forming an inclined side, the inclination suitably being 1:7. 7. Apparatus as claimed in any one of claims 1-6, wherein the plate assembly (1) or assemblies (1, 9) are provided between two side baffles (14, 15) or the like which converge towards the intake side (16) of the assemblies as counted in the direction of motion (5) of the waves, the angular change of the converging side baffles suitably being 1:7.

Inventors: HENRIKSON STIG ARVID, HENRIKSON, STIG, ARVID
Applicants: HENRIKSON STIG ARVID, HENRIKSON, STIG, ARVID
Application year: 1988
Main classification: E02B9
IPC codes: F03B13