Wave Energy Converter

Abstract

Apparatus ( 10 ) rests on the seabed at a location below sea level for capturing wave energy. The apparatus ( 10 ) comprises a body structure ( 11 ) having a diaphragm ( 25 ) adapted to deflect in response to wave action. A working chamber ( 27 ) is disposed immediately below the diaphragm ( 25 ) and contains a compressible fluid such as air. A pump system ( 43 ) is accommodated within the working chamber ( 27 ). The pump system ( 43 ) comprises two reciprocating pumps ( 45, 47 ) operating in opposition. The pumps ( 45, 47 ) are operably connected to the diaphragm ( 25 ) through a lever mechanism ( 61 ). Because of the geometry of the lever mechanism ( 61 ), the stroke length of each pump ( 45, 47 ) is less than the amplitude of displacement of the diaphragm ( 25 ) as it moves in response to wave action. Thus, the lever mechanism ( 61 ) increases the force acting on each pump ( 45, 47 ) by a given ratio and reduces the stroke of each pump by the same ratio. The reduction in stroke length provides for compact construction so that the pumps ( 45, 47 ) can be readily accommodated within the working chamber ( 27 ). The pumps ( 45, 47 ) draw seawater from the environment about the apparatus ( 10 ) and discharge the seawater at a high-pressure. The high-pressure seawater generated by the pumps can be piped to shore for use in any appropriate purpose.

1 . Apparatus for capturing wave energy in a body of water, the apparatus comprising a body structure having a portion thereof adapted to deflect in response to wave action, a reciprocating pump defining a pumping chamber adapted to undergo expansion and contraction in response to deflection of said portion of the body structure, the pumping chamber having an inlet communicating with a fluid source and an outlet, whereby fluid from the fluid source is drawn into the pumping chamber upon volume expansion thereof and is discharged from the pumping chamber upon volume reduction thereof through the outlet, the pump being operably connected to said portion of the body structure by a mechanism providing a velocity ratio of less than 1.0.  
   
   
       2 . Apparatus according to  claim 1  wherein the mechanism comprises a lever, the pump being operably connected to the lever at a location closer to the fulcrum of the lever than the location at which said portion is connected to the lever.  
   
   
       3 . Apparatus according to  claim 1  wherein the mechanism comprises a lever operably connected to at least two pumps.  
   
   
       4 . Apparatus according to  claim 3  wherein the lever is operably connected to two pumps disposed one to each side of the lever fulcrum, whereby the pumps operate in opposition.  
   
   
       5 . Apparatus according to  claim 1  wherein there is a plurality of levers operably connected to said portion, each lever operating at least one pump.  
   
   
       6 . Apparatus according to  claim 5  wherein there are three levers arranged in a delta formation, each lever being operably connected to said portion.  
   
   
       7 . Apparatus according to  claim 2  wherein the or each lever is of framed construction to provide both vertical and lateral rigidity under load.  
   
   
       8 . Apparatus according to  claim 1  wherein said portion of the body structure adapted to deflect in response to wave action comprises a diaphragm exposed to a body of water incorporating wave action.  
   
   
       9 . Apparatus according to  claim 8  wherein the diaphragm comprises a substantially rigid portion and a flexible portion, the mechanism being operably connected to the rigid portion.  
   
   
       10 . Apparatus according to  claim 9  wherein the mechanism is coupled rigidly to the rigid portion of the diaphragm.  
   
   
       11 . Apparatus according to  claim 9  wherein the body structure includes a working chamber which is disposed below the diaphragm and which is adapted to contain a compressible fluid such as air.  
   
   
       12 . Apparatus according to  claim 11  wherein the or each lever is accommodated in, or at least extends into, the working chamber for connection to the diaphragm.  
   
   
       13 . Apparatus according to  claim 2  wherein the or each lever is guided as it undergoes reciprocating movement in response to movement of the diaphragm.  
   
   
       14 . Apparatus according to  claim 2  wherein the or each lever is provided with a counter-weight to provide assistance for a return stroke of the diaphragm following completion of a power stroke thereof.  
   
   
       15 . Apparatus according to  claim 1  wherein the body structure comprises a ballast chamber for accommodating ballast material such as sand.  
   
   
       16 . Apparatus according to  claim 15  wherein the ballast chamber surrounds the working chamber.  
   
   
       17 . Apparatus according to  claim 1  wherein the fluid being pumped comprises water drawn from the body of water from which wave energy is to be captured.  
   
   
       18 . Apparatus according to  claim 17  further comprising a filtration system for filtering the water, the filtration system comprising saturated sand employed as ballast material for the apparatus.  
   
   
       19 . Apparatus for capturing wave energy in a body of water, the apparatus comprising a body structure having a portion thereof adapted to deflect in response to wave action, a reciprocating pump defining a pumping chamber adapted to undergo expansion and contraction in response to deflection of said portion of the body structure, the pumping chamber having an inlet communicating with a fluid source and an outlet, whereby fluid from the fluid source is drawn into the pumping chamber upon volume expansion thereof and is discharged from the pumping chamber upon volume reduction thereof through the outlet, the pump being operably connected to said portion by a mechanism whereby the stroke length of the pump is less than the amplitude of displacement of said portion undergoing movement in response to wave action.  
   
   
       20 . Apparatus for capturing wave energy in a body of water, the apparatus comprising a body structure having a portion thereof adapted to deflect in response to wave action, a reciprocating pump defining a pumping chamber adapted to undergo expansion and contraction in response to deflection of said portion of the body structure, the pumping chamber having an inlet communicating with a fluid source and an outlet, whereby fluid from the fluid source is drawn into the pumping chamber upon volume expansion thereof and is discharged from the pumping chamber upon volume reduction thereof through the outlet, the pump being operably connected to said portion by a lever, the pump being operably connected to the lever at a location closer to the fulcrum of the lever than the location at which said portion is connected to the lever.  
   
   
       21 . Apparatus according to  claim 20  wherein the diaphragm comprises a substantially rigid portion and a flexible portion, the lever being operably connected to the rigid portion of the diaphragm.  
   
   
       22 . (canceled)