Wave energy converter

Abstract

A wave energy harnessing converter ( 1 ) has a tube ( 3 ) which floats on the sea. A water inlet ( 2 ) delivers water to the tube, and an air inlet ( 2 ) delivers air to the tube ( 3 ). The tube has sufficient buoyancy and flexibility to float on the water and conform to the shape of waves when the tube extends substantially in the direction of travel of the waves, causing water in the tube to be conveyed from the inlet and to be pressurised and the air to be compressed in a series of moving air pockets. The tube is reinforced to minimise energy losses through distortion or elongation. A converter output section ( 10 ) for receiving water and compressed air from the tube ( 3 ) for providing energy.

1 - 40 . (canceled) 
     
     
         41 . A wave energy converter comprising:
 at least one tube to float on the sea or other water body,   a water inlet for delivering water to the tube,   an air inlet for delivering air to the tube,   wherein the tube has sufficient buoyancy and flexibility to float on the water and conform to the shape of waves when the tube extends substantially in the direction of travel of the waves, causing water in the tube to be conveyed from the inlet and to be pressurised and the air to be compressed;   a system output section for receiving water and compressed air from the tube for providing energy.   
     
     
         42 . The wave energy converter as claimed in  claim 41 , wherein said tube has a diameter is in the range of 100 mm to 2 m. 
     
     
         43 . The wave energy converter as claimed in  claim 41 , wherein the length of at least one tube is in the range of 100 m and 1000 m. 
     
     
         44 . The wave energy converter as claimed in  claim 41 , wherein at least one tube has a longitudinal stiffener. 
     
     
         45 . The wave energy converter as claimed in  claim 41 , wherein at least one tube has a longitudinal stiffener which extends along a neutral plane of the tube. 
     
     
         46 . The wave energy converter as claimed in  claim 41 , wherein at least one tube has a longitudinal stiffener on each opposed side of the tube. 
     
     
         47 . The wave energy converter as claimed in  claim 41 , wherein there is a plurality of juxtaposed and interconnected tubes forming a tube assembly. 
     
     
         48 . The wave energy converter as claimed in  claim 41 , wherein there is a plurality of juxtaposed and interconnected tubes forming a tube assembly; and wherein the tube assembly comprises a skirt along sides of the assembly to reduce air ingress under the tubes. 
     
     
         49 . The wave energy converter as claimed in  claim 41 , further comprising a tensioning mechanism for varying overall length of the tube in the horizontal plane. 
     
     
         50 . The wave energy converter as claimed in  claim 41 , further comprising a tensioning mechanism for varying overall length of the tube in the horizontal plane; and wherein the tensioning mechanism comprises tensioning ropes extending between the ends of the tube, and a control mechanism to adjust the length of the ropes. 
     
     
         51 . The wave energy converter as claimed in  claim 41 , further comprising water outtake means for removing water from a location to define a plurality of tube stages, in which pressure of stages increases with distance from the inlet end. 
     
     
         52 . The wave energy converter as claimed in  claim 41 , further comprising water outtake means for removing water from a location to define a plurality of tube stages, in which pressure of stages increases with distance from the inlet; and further comprising a manifold between the stages for routing of air and water between different tubes. 
     
     
         53 . The wave energy converter as claimed in  claim 41 , further comprising water outtake means for removing water from a location to define a plurality of tube stages, in which pressure of stages increases with distance from the inlet; and wherein there are progressively fewer tubes as pressure increases. 
     
     
         54 . The wave energy converter as claimed in  claim 41 , further comprising water outtake means for removing water from a location to define a plurality of tube stages, in which pressure of stages increases with distance from the inlet; and wherein the tubes of the successive stages are arranged in parallel. 
     
     
         55 . The wave energy converter as claimed in  claim 41 , further comprising water outtake means for removing water from a location to define a plurality of tube stages, in which pressure of stages increases with distance from the inlet; and wherein the tubes of the successive stages are arranged in parallel; and wherein the higher pressure stages are biased towards being located centrally. 
     
     
         56 . The wave energy converter as claimed in  claim 41 , wherein the water and the air inlets are combined in a combined inlet comprising:
 a rigid tube having a mouth to receive water and air, the mouth having a bottom plate located to cut the top of a wave to take advantage of the momentum of the forward-rotating portion of the water at the top of the wave, and   buoyancy means to position the rigid tube to receive air and water with the inlet tube sloped downwardly from its front.   
     
     
         57 . The wave energy converter as claimed in  claim 41 , wherein the water and the air inlets are combined in a combined inlet comprising:
 a rigid tube having a mouth to receive water and air, the mouth having a bottom plate located to cut the top of a wave to take advantage of the momentum of the forward-rotating portion of the water at the top of the wave,   buoyancy means to position the rigid tube to receive air and water with the inlet tube sloped downwardly from its front, and   wherein the inlet comprises a tapered or curved guide for guiding water into the mouth.   
     
     
         58 . The wave energy converter as claimed in  claim 41 , wherein the water and the air inlets are combined in a combined inlet comprising:
 a rigid tube having a mouth to receive water and air, the mouth having a bottom plate located to cut the top of a wave to take advantage of the momentum of the forward-rotating portion of the water at the top of the wave,   buoyancy means to position the rigid tube to receive air and water with the inlet tube sloped downwardly from its front, wherein the inlet comprises a tapered or curved guide for guiding water into the mouth, and   wherein the guide extends downwardly below the mouth.   
     
     
         59 . The wave energy converter as claimed in  claim 41 , wherein the water inlet is in the form of a substantially vertical riser, and comprises a pumping means to pump water upwardly through the riser. 
     
     
         60 . The wave energy converter as claimed in  claim 41 , wherein:
 the water inlet is in the form of a substantially vertical riser, and comprises a pumping means to pump water upwardly through the riser; and   wherein the pumping means comprises a feedback link from the outlet section arranged to deliver compressed air to the riser to provide an air lift pump, said link providing at least part of the air inlet.   
     
     
         61 . The wave energy converter as claimed in  claim 41 , wherein:
 the water inlet is in the form of a substantially vertical riser, and comprises a pumping means to pump water upwardly through the riser; and   wherein the pumping means comprises a feedback link from the outlet section arranged to deliver compressed air to the riser to provide an air lift pump, said link providing at least part of the air inlet; and   the feedback link includes an air storage tank, and the storage tank is adapted to release air into the riser.   
     
     
         62 . The wave energy converter as claimed in  claim 41 , wherein the water inlet comprises an oscillating water column. 
     
     
         63 . The wave energy converter as claimed in  claim 41 , wherein the water inlet comprises an oscillating water column; and
 wherein the air inlet comprises a one-way valve at an upper end of the oscillating water column.   
     
     
         64 . The wave energy converter as claimed in  claim 41 , wherein the air inlet comprises a bellows. 
     
     
         65 . The wave energy converter as claimed in  claim 41 , wherein the air inlet comprises a bellows; and wherein the inlet comprises a buoy for supporting the bellows. 
     
     
         66 . The wave energy converter as claimed in  claim 41 , wherein the air inlet comprises a floating air trap having an inlet valve and an outlet for pulsed air driven by rising waves. 
     
     
         67 . The wave energy converter as claimed in  claim 41 , wherein the output section comprises a flow restrictor to build pressure of air and water in each tube; and wherein the flow restrictor is an electricity generator such as a turbine. 
     
     
         68 . The wave energy converter as claimed in  claim 41 , wherein the output section comprises an air/water separator. 
     
     
         69 . The wave energy converter as claimed in  claim 41 , wherein the output section comprises an air turbine and a separate water turbine.