AU4600900A - Wave-powered pump - Google Patents

Description

WO 00/70218 PCT/IB00/00627 1 WAVE-POWERED PUMP This invention relates to pumping a fluid by means of wave action. It relates more specifically to a method of pumping a fluid by means of wave 5 action, and to a wave action pumping installation. The Applicant expects the invention to be particularly advantageously applicable to the pumping of liquid, for example water, more especially sea water, but the scope of the invention is not limited to pumping of liquid, or water or sea water. ) According to a first aspect of this invention, there is provided a method of pumping a fluid by means of wave action, the method including, in a pump arranged to pump the fluid, cyclically reciprocating a pump member alternatingly in opposite directions, the pump member being driven in one direction by means of a buoyancy member subjected to the wave action, and in WO 00/70218 PCT/IB00/00627 2 the opposite direction by means of a biassing force or torque opposing the buoyancy member. The method may be carried out in association with a body of water undergoing wave action. In some methods, the fluid being pumped may then be water of the body of water. Said buoyancy member may be a primary buoyancy member, biassing being effected by means of a secondary buoyancy member having less buoyancy than the primary buoyancy member, the primary and secondary buoyancy members acting on a lever at opposed sides of a fulcrum of the lever. ) The buoyancy of the secondary buoyancy member may be about one half of the buoyancy of the primary buoyancy member. Instead, biassing may be effected by means of a counterweight arranged to counter the buoyancy effect of the buoyancy member, the counterweight having a weight which is less than the buoyancy force. The counter weight may be about one half of the buoyancy force. The pump may include an arcuate pump chamber and the pump member may be in the form of a vane which can be swept to and fro through the pump chamber, the buoyancy force by the buoyancy member or the primary WO 00/70218 PCT/IB00/00627 3 buoyancy member sweeping the vane in one direction and the biassing force or torque sweeping the vane in the opposite direction. By way of development, the pump may include a plurality of arcuate pump chambers and the pump member may be in the form of a corresponding plurality of vanes which can be swept to and fro through the respective pump chambers. In yet a further method, the pump may be a squeeze pump, the pump chamber then being conduit means for the fluid and the pump member being a squeeze member arranged to squeeze the conduit means. The fluid may then be a gas, e.g. air. In accordance with a second aspect of this invention, there is provided a wave action pumping installation for fluid suitable for location in association with a body of water undergoing wave action, the pumping installation including a pump including a pump chamber, a reciprocating pump member reciprocal to and fro to effect pumping and valve means for controlling flow of fluid toward and from the pump chamber; biassing means for biassing the pump member in a predetermined direction toward a starting condition; WO 00/70218 PCT/IB00/00627 4 a buoyancy member having buoyancy in water and being connected to the pump member cyclically to drive the pump member from the starting condition when the buoyancy member is lifted by wave action in use. In one kind of embodiment, said buoyancy member may be a primary 5 buoyancy member, the biassing means including a secondary buoyancy member having a predetermined buoyancy which is smaller than the buoyancy of the primary buoyancy member, the primary and secondary buoyancy members being connected to a lever at opposed sides of a fulcrum of the lever, the lever being drivingly connected to the pump member. The secondary buoyancy may be ) about one half of the primary buoyancy. The buoyancy members may be in the form of floats. The floats may be connected to the lever by elongate flexible elements at positions which may be equidistant from the fulcrum, one of the floats being larger than the other and being connected to the lever arm by an elongate flexible element having a length which is greater than that of the other i flexible element. In another kind of embodiment, the biasing means may include a counterweight arranged only partially to counteract the effect of the buoyancy member. The counterweight may be about one half of the buoyancy force.

WO 00/70218 PCT/IB00/00627 5 The pump may be an arcuately reciprocal vane pump, the pump chamber being an arcuate pump chamber and the pump member being a vane arcuately pivotal to and fro in the pump chamber. By way of development the pump may be a composite arcuately reciprocal vane pump, which includes a plurality of arcuate pump chambers and a corresponding plurality of pump members in the form of vanes respectively arcuately pivotal to and fro in the respective pump chambers. In another embodiment, the pump may be a squeeze pump, the pump chamber being a conduit means for the fluid and the pump member being ) a squeeze member arranged to squeeze the conduit means. The invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings. In the drawings: Figure 1 shows a schematic side view of a pumping installation in accordance with the invention; Figure 2 shows a schematic plan view of a composite squeeze pump forming part of the pumping installation of Figure 1; Figure 3 shows a side view of the composite squeeze pump shown in Figure 2; WO 00/70218 PCT/IB00/00627 6 Figure 4 shows another embodiment of a pumping installation in accordance with the invention; Figure 5 shows, in side view, another embodiment of a pump suitable to form part of a pumping installation in accordance with the invention; 5Figure-6 shows, in axial section, but without hatching for convenience of drawing, the pump of Figure 5; Figure 7 shows a schematic view corresponding to Figure 6, with inlet and outlet ports and flow conduits leading toward the inlet ports and away from the outlet ports; ) Figure 8 shows a view corresponding to Figure 6 but of a developed embodiment; and Figure 9 shows in cross-sectional view (but without hatching for ease of drawing), yet a further embodiment of a pump suitable to form part of a pumping installation in accordance with the invention. In Figures 1 to 3 of the drawings, reference numeral 10 refers generally to a first embodiment of a pumping installation in accordance with the invention. The pumping installation 10 includes a platform 12 anchored to the sea bed 60 by means of anchors 62. A circular cylindrical drum 14 is mounted on the platform 12, the axis of the drum extending decumbently or generally horizontally. The installation 10 further includes a lever arm 16 pivotally mounted WO 00/70218 PCT/IB00/00627 7 intermediate its ends via a fulcrum 18 which is coincident with the axis of the drum 14. The pumping installation 10 further includes two composite squeeze pumps 20 in a manner described in more detail below. In the embodiment shown, the pumping installation 10 is intended 5 for use in pumping sea water making use of wave action or wave energy as the driving force. To this end, the pumping installation 10 includes a primary buoyancy member in the form of a float 24 connected to the lever arm 16 adjacent its one end by an elongate flexible element, e.g. a cable 26, and a secondary buoyancy member in the form of a float 28 connected to the lever arm ) 16 adjacent its other end by an elongate flexible element, e.g. a cable 30. The cable 26 is substantially longer than the cable 30 and, in addition, the buoyancy of the float 24 is substantially greater than the buoyancy of the float 28 e.g. about twice as large. The floats 24, 28 are configured such that torque applied to the lever arm 16 as a result of the buoyancy of the float 5 24 is approximately double that applied to the lever arm as a result of the buoyancy of the float 28. With particular reference now to Figures 2 and 3 of the drawings, each squeeze pump 20 includes a pair of manifolds 32, 34 and a plurality of lengths of pipe 36 connected at the one ends to the manifold 32 and at the other ) ends to the manifold 34.

WO 00/70218 PCT/IB00/00627 8 Both manifolds 32, 34 are connected via flow lines 38, 40, respectively to an inlet 42. Non-return valves 44, 46 are mounted in the respective flow lines 38, 40. Similarly, the manifolds 32, 34 are connected via flow lines 48, 50 5 respectively, to an outlet 52. Once again, non-return valves 54, 56 are mounted in the flow lines 48, 50. Each squeeze pump 20 includes a compression member 22. Each compression member 22 is in a form of a roller 58 rotatably mounted on the lever arm 16 such that the pipes 36 are laterally compressed ) between the associated roller 58 and a radially inner surface of the drum 14 in a fluid tight manner. In use, as a wave approaches, buoyancy forces acting on the float 24 cause the float 24 to move upwardly and the lever arm 16 to pivot in the direction of arrow 64 causing the rollers 58 to move in a corresponding direction. 5As can best be perceived from Figures 2 and 3 of the drawings, as the roller 58 moves in the direction of arrow 64 towards the manifold 32 the effective length of each of the pipes 36 between the roller 58 and the manifold 32 is decreased so that water is discharged under pressure from the manifold WO 00/70218 PCT/IB00/00627 9 through the non-return valve 54 and the outlet 52. Similarly, the effective length of each pipe 36 between the manifold 34 and the roller 58 increases thereby resulting in a decrease in water pressure in the manifold 34 and the lengths of pipe 36 between the manifold 34 and the roller 58. This causes water to be 5 drawn in through the inlet 42 and the non-return valve 46 into the manifold 34 and the lengths of pipe between the manifold 34 and the roller 58. As the wave passes, the water level drops so that the float 24 recedes, the cable 26 slackens, and pull on the lever 16 in the directions 64 ceases. By virtue of the buoyancy forces acting on the float 28, the lever arm 16 3 is caused to pivot in a direction opposite to the direction of the arrow 64. This results in the roller 58 moving toward the manifold 34 thereby compressing water in the portions of the pipes 36 between the roller 58 and the manifold 34 resulting in the non-return valve 46 being closed and the water being discharged through the non-return valve 56 to the outlet 52. The non-return valve 54 closes. 5 Water is drawn through the inlet 42 and the non-return valve 44 into the manifold 32 and into those portions of the pipes 36 intermediate the manifold 32 and the rolLer 58. With reference to Figure 1, it is to be appreciated that the two squeeze pumps 20 are operated simultaneously, the arrangements in Figures 2 ) and 3 being duplicated.

WO 00/70218 PCTIIB00/00627 10 In this way, water can be pumped in a more-or-less continuous manner as a result of the action of the waves or swells. If desired, more than two pumps 20 and corresponding compression members 22 can be provided. 5As mentioned above, the embodiment shown in Figures 1 to 3 is intended for use in pumping sea water and will accordingly be constructed of components which are resistant to attack from sea water. The pumped water can be used for any desired application, e.g. for the generation of electricity and/or for desalination. The Inventor believes that the installation could be used ) as a compressor to compress air or the like. In this case a plurality of pumps will be provided. The lengths of the pipes will be reduced. The Inventor believes that this arrangement will permit air to be compressed up to a pressure of about 12 BAR or more with relatively small movements of the lever arm. Reference is now made to figure 4 of the drawings, in which 5 reference numeral 70 refers generally to another embodiment of a pumping installation in accordance with the invention. The pumping installation 70 includes pumping apparatus, generally indicated by reference numeral 72.

WO 00/70218 PCT/IB00/00627 11 The pumping apparatus 72 includes a platform 74 which is anchored to the sea bed 60 by anchors 76. A lever arm 78 is pivotally connected toward its one end via a fulcrum 80 to the platform 74. A float 82 is connected via an elongate flexible element, e.g. a cable 84 to the lever arm 78 at a position remote 5 from the fulcrum 80, i.e, adjacent an opposed end thereof. A counterweight 86 is connected via a cable 88 to the lever arm 78 at the same position as the float 82. The weight of the counterweight 86 is about one half of the buoyancy force of the water on the float 82. The pumping apparatus further includes a double acting piston and D cylinder arrangement 90 which is mounted between the lever arm 78 and the platform 74. The cylinder of the piston and cylinder arrangement 90 is communicated at opposite sides of the piston to an inlet 92 via flow lines 94, 96. Similarly, an outlet 98 is communicated at opposite sides of the piston, in flow 5 communication with the cylinder via flow lines 100, 102. Non-return valves 104, 102, 106, 105 are mounted in the respective flow lines 94, 96, 100, 102. The inlet 92 is connected to a delivery end of a suction line 107 the other or inlet end of the suction line 107 being positioned below the surface of the sea bed 60.

WO 00/70218 PCT/IB00/00627 12 In use, as a wave or swell arrives causing the surface level to rise, the buoyancy forces acting on the float 82 cause the lever arm 78 to be displaced in the direction of arrow 109. The buoyancy force is greater than and overcomes gravity force on the counterweight 86. This causes the piston to be displaced 5 upwardly within the cylinder causing water to be drawn through the inlet 92, the flow line 96 and the non-return valve 108 into the cylinder. Similarly, water in the cylinder above the piston is pressurized and is discharged through the non return valve 106 and the flow line 100 to the outlet 98. As the wave or swell passes and the surface level drops, the float 82 recedes with the water level the D cable 84 slackens and the pull on the lever end ceases. The force of gravity on the weight 86 then causes the lever arm 78 to pivot in a direction opposite to the direction of arrow 109. This results in water being drawn through the inlet 92, the flow line 94 and the non-return valve 104 into the cylinder. Similarly, water is discharged through the non-return valve 105 and flow line 102 to the outlet 5 98. In this way, a more-or-less continuous pumping process can be achieved. Positioning the inlet end of the suction line 107 below the surface of the sea bed 60 results in the water being drawn into the suction line first 3 passing through the material of the sea bed 60 adjacent to the inlet end of the WO 00/70218 PCT/IB00/00627 13 suction line which serves as a natural filter for the water. If desired a further in line or series filter can be provided in the inlet 92. It should be appreciated, that the pumping apparatus of the pumping installation 70 can take any suitable form and, for example, may be in the form 5 of the pumping apparatus 10. The Inventor believes that the pumping installation in accordance with the invention will provide pumped water which, as mentioned above, can be used to drive a generator, e.g. via a turbine, to generate electricity or be used for desalination in a cost effective manner. ) With reference to Figures 5 and 6 of the drawings, a pump suitable to form part of a pumping installation in accordance with the invention is generally indicated by reference numeral 110. The pump 110 can, for example, be used instead of the squeeze pumps 20 in Figure 1, or instead of the plunger and cylinder pumping arrangement 90 of Figure 4. 5 The pump 110 includes a shaft assembly generally indicated by reference numeral 112 and comprising a shaft 14 and end flanges 116 incorporating rotation means such as sealed bearings rotatably supporting the shaft 114 in the end flanges 116.

WO 00/70218 PCT/IB00/00627 14 The pump 110 further comprises a round cylindrical barrel 118 having end flanges 120 at opposed ends thereof. The pump 110 is assembled in concentric fashion such that the end flanges 116, 120 and the barrel 118 are concentric with the shaft 114. At each end of the pump 110, the respective end flange 116 rotatably supporting the shaft 114 and the corresponding end flange 120 fixed to that end of the barrel 118 are secured together by means of nut and bolt arrangements 122. A gasket is preferably provided intermediate the corresponding faces of the flanges. With reference more specifically to Figure 6, there is provided a ) composite vane generally indicated by reference numeral 124 which extends diametrically through the shaft 114 and which is fixed to the shaft 114. Thus, to either side, radially and longitudinally extending vanes 124.1 and 124.2 are provided. Also with reference more specifically to Figure 6, internally of the barrel 118, there is provided an opposing pair of radially and longitudinally extending compartment baffles 126 dividing the interior of the barrel 18 into semi-cylindrical, longitudinal, chambers. Inner free ends of the compartment baffles 126 stop just shy of a periphery of the shaft 114 to allow running clearance for the shaft 114. The compartment baffles 126 are anchored at their outer radial ends by means of bolts or studs and nuts 128 thus rendering the compartment baffles integral with the barrel 18.

WO 00/70218 PCT/IB00/00627 15 Outer radial ends of the vane 124.1 and 124.2 have little, but nevertheless running, clearance with an internal periphery of the barrel 118. So as not to clutter up the drawing, hatching is generally not shown in Figure 6 and inlet and outlet ports and corresponding flow conduits which are 5 described herebelow are not shown in Figure 6. With reference to Figure 7, inlet and outlet ports, flow conduits leading toward the inlet ports and away of the outlet ports and the like are now described. It is to be appreciated that the compartment baffles 126 divide the cylinder 118 in upper and lower symmetrical halves. Each half forms a chamber ) 150. To one side of the vane 124.1, a first sub-chamber 150.1 is formed. To an opposed side of the vane 124.1, a second sub-chamber 150.2 is formed. Similarly, to one side of the vane 124.2 a third sub-chamber 150.3 is formed, and to an opposed side of the vane 124.2, a fourth sub-chamber 150.4 is formed. Closely adjacent the inner periphery of the barrel 118, and proximate S onabaffle 126, at one end of the chamber, more specifically in one end plate 120, in the first sub-chamber 150.1, there is provided a first inlet port 130.1. Axially opposite the inlet port 130.1, in the opposed end flange 120, in the first sub-chamber 150.1, there is provided afirst outlet port 140.1. In Figure 7, the outlet port 140.1 is shown in dotted adjacent the first inlet port 130.1. In fact ) it will be in register with the inlet port 130.1 but in the opposite end flange.

WO 00/70218 PCT/IB00/00627 16 Correspondingly, in the opposite sub-chamber 150.2, there is provided a second outlet port 140.2 in the end flange 120 having the inlet port 130.1. Similarly, in the opposite end flange 120, axially opposite to the second outlet port 140.2 i.e. in register therewith, there is provided a second inlet port 130.2 shown in dotted. Thus the sub-chamber 150.1 has, at opposite ends thereof, the inlet port 130.1 and the outlet port 140.1. Similarly, the second sub chamber 150.2 has, at opposite ends thereof, the inlet port 130.2 and the outlet port 140.2. Similarly, the third and fourth sub-chambers 150.3, 150.4 have ) respective inlet ports 130.3 and 130.4, and outlet parts 140.3 and 140.4. A supply conduit leading from a source of fluid to be pumped as indicated by reference numeral 136 extends via an inlet one way valve 134 into a branch 132.4 leading to the fourth inlet port 130.4 in the sub-chamber 150.4. A branch 132.2 parallel to the branch 132.4 extends to the inlet port 130.2 in i the sub-chamber 150.2. Similarly, branch conduits 142.1 and 142.3 lead from the first and third outlet ports 140.1 and 140.3 via a one way valve 144 into a delivery line 146 extending to a sink for the fluid to be pumped.

WO 00/70218 PCT/IB00/00627 17 A similar inlet system serves the sub-chambers 150.1 and 150.3. Also, a similar outlet system serves the sub-chambers 150.2 and 150.4. However so as not to clutter up the drawing, the duplicated systems are not shown in the drawing. In use, assume that the vanes 124.1 and 124.2 are in positions pivoted anti-clockwise from the positions shown in Figure 7, i.e. adjacent the respective compartment baffles 126 and proximate respectively the first inlet port 130.1 and the first outlet port 140.1; and the third inlet port 130.3 and the third outlet port 140.3. When in those positions, the first sub-chambers 150.1 and 150.3 between the vanes 124.1 and 124.2 and the proximate compartment baffles 126 are at minimum volume. Correspondingly, the second and fourth sub chambers 150.2 and 150.4 intermediate the vanes 124.1, 124.2 and the remote compartment baffles 126 are at maximum volume. The shaft 114 is pivoted clockwise through an angle less than 1800 to sweep the vanes 124.1, 124.2 to angular positions proximate the opposed compartment baffles 126 adjacent respectively the second outlet port 140.2 and the second inlet port 130.2; and the fourth outlet port 140.4 and the fourth inlet port 130.4. While this stroke takes place, the first sub-chamber 150.1 with which the inlet port 130.1 is in communication, and the third sub-chamber 150.3 ) with which the inlet port 130.3 is in communication increase in volume with a consequent decrease in pressure. Thus, fluid is drawn from the source via the WO 00/70218 PCT/IB00/00627 18 duplicated inlet system (not shown) and the ports 130.1 and 130.3 into the first and third sub-chambers 150.1 and 150.3 thus filling the first and third sub chambers 150.1, 150.3. During a return stroke of the vanes 124.1, 124.2 in which they are pivoted in anti-clockwise direction to angular positions respectively adjacent the first inlet port 130.1 and first outlet port 140.1; and the third inlet port 130.3 and the third outlet port 140.3 the second sub-chamber 150.2 and fourth sub chamber 150.4 are charged via the supply line 136, one-way valve 134, branch lines 132.2, 132.4 and inlets 130.2, 130.4 in a similar manner to what was described for the first and third sub-chambers during the first stroke of the vanes 124.1, 124.2. Simultaneously, during the reverse stroke, the first and third sub chambers 150.1, 150.3 decrease in volume with a consequent increase in pressure. The fluid is pressurized through the first and third outlet ports 140.1, 140.3 via the flow conduits 142.1, 142.3 the corresponding one way valve 144 and the delivery conduit 146 to the sink. The above procedure is repeated cyclicly. It is to be appreciated that diagonally opposed quadrants of the pump work in combination to render the pump double acting. Branch lines leading to the respective inlet ports and outlet ports are appropriately connected to respectively the supply conduit 136 and the delivery conduit 146.

WO 00/70218 PCT/IB00/00627 19 It is further to be appreciated that the embodiment of Figure 7 can have only a single vane 124, or a double vane (as described) or multiples. It is believed that only four one-way valves will be required for two or more vanes. With reference to Figure 8, by way of development, seal assemblies generally indicated by reference numeral 160 are provided at the radially outer ends of the vanes 124 and at the radially inner ends of the compartment baffles 126 to minimize or prevent leakage. The Applicant regards it as a first advantage that a simple, inexpensive and elegant pump is provided to use a rocking or to and fro pivoting action which can be obtained, for example from wave action, to pump a fluid, for example water. The Applicant regards it as a further advantage that to and fro pivoting or rocking action obtained from other sources can be used to drive a pump as disclosed. For example, the Applicant envisages that water can be pumped in rural areas by using drive from a see-saw to pump water while children are using the see-saw. This can also be used in amusement parks for purposes not necessarily utilitarian. With reference to Figure 9, yet a further embodiment of a pump suitable to form part of a pumping installation in accordance with the invention WO 00/70218 PCT/IB00/00627 20 is generally indicated by reference numeral 210. The pump 210 is similar to the pump 110 of Figures 6 and 7. Like reference numerals refer to like components or features, and the pump of Figure 9 is not described in detail. Differences between the pump of Figures 6 and 7 on the one hand and the pump of Figure 5 9 on the other hand will merely be emphasized. The pump 210 includes a spherical pump body 218 which is provided in two halves with circular flanges which are closed onto and secured to each other as indicated at 217 to form the spherical body. It is envisaged that the pump body may be formed of mouldings of synthetic polymeric material. ) In this embodiment, the pump 210 has a single pump chamber only, but it will readily be understood by a person skilled in the art that it can be provided with two or even more pump chambers similarly to the pump of Figures 6 and 7. The pump 210 has a single baffle 226 in the form of a semi-circle. 5 Thabaffle 226 is secured, for example by welding, or by being integrally moulded along its semi circular periphery to an inner periphery of the pump body 218. Along a free, diametrical extremity of the baffle 226, it is sealed as indicated by reference numeral 260.1 to a shaft 214 to allow for relative rotation of the shaft.

WO 00/70218 PCT/IB00/00627 21 The pump 210 has a single semi-cylindrical vane 224 which is secured, for example by means of welding, to the shaft 214. A semi cylindrical free extremity of the vane 224 is sealed as indicated by reference numeral 260.2 against an inner periphery of the pump body 218 to allow sliding of the vane 224 5 through the pumping chamber indicated by reference numeral 250. The vane is swept through an angle marginally short of 3600 though the pumping chamber 250 by appropriate pivoting of the shaft 214. It is to be appreciated that the shaft 214 is pivoted by means of wave action, which fluctuates and it is thus to be appreciated that the shaft 214 does not necessarily pivot through its entire arc 0 at every stroke. This, however, does not influence the principle of operation of the pump 210. To one side of the baffle 226, there is provided an inlet 230.1 and an outlet 240.1 which inlet and outlet are shown as a single port. Two ports are in fact provided of which only one is shown in the drawing. Similarly, to the 5 other side of the baffle 226, there is provided a second inlet port 230.2 and a second outlet port 240.2, again only one being shown in the drawing. The inlet ports 230.1, 230.2 are communicated via appropriate non return valves to a source of fluid to be pumped. Similarly, the outlet ports 240.1, 240.2 are communicated via appropriated non-return valves to a sink to which ) fluid is to be pumped. The arrangement is similar to the arrangements shown and described above.

WO 00/70218 PCT/IB00/00627 22 Operation of the pump 210 is similar to that of the pump 110 in that, when the vane 224 moves from a position proximate the inlet valve 230.1 in a direction which is clock-wise in Figure 9, fluid such as water is drawn into the chamber via the inlet 230.1, while water which has perviously been drawn into the chamber 250 is expelled under pressure via the outlet 240.2. At the end of the stroke, the vane 224 is returned to charge the chamber 250 at the traling side of the vane 224 via the inlet 230.2, while water is expelled under presure at the leading end of the vane 224 via the outlet 240.1. Although operation of the pump 210 is similar to operation of the ) pump of Figures 6 and 7, the Applicant believes that a pump having a spherical body has a number of advantages, for example that a sphere is the strongest constructional form for withstanding pressure, thus requiring merely a thin shell thus saving on weight and costs. Furthermore, it is believed that the sperical form will render the pump less prone to drag by currents in the water. An i important advantage is that the seals employed in the pump 210 will not extend around corners, but will extend merely along smooth arcs. Such an arrangement promotes integrity in sealing.

Claims (14)

1. A method of pumping a fluid by means of wave action, the method including, in a pump arranged to pump the fluid, cyclically reciprocating a pump member alternatingly in opposite directions, the pump member being driven in one 5 direction by means of a buoyancy member subjected to the wave action, and in the opposite direction by means of a biassing force or torque opposing the buoyancy member.

2. A method as claimed in Claim 1 which is carried out in association with a body of water undergoing wave action.

) 3. A method as claimed in Claim 2 in which the fluid being pumped is water of the body of water.

4. A method as claimed in any one of Claim 1 to Claim 3 inclusive in which said buoyancy member is a primary buoyancy member and in which biassing is effected by means of a secondary buoyancy member having less buoyancy than the primary buoyancy member, the primary and secondary buoyancy members acting on a lever at opposed sides of a fulcrum of the lever.

5. A method as claimed in any one of Claim 1 to Claim 3 inclusive in which biassing is effected by means of a counterweight arranged to counter the WO 00/70218 PCT/IB00/00627 24 buoyancy effect of the buoyancy member, the counterweight having a weight which is less than the buoyancy force.

6. A method as claimed in any one of Claim 1 to Claim 5 inclusive in which the pump includes an arcuate pump chamber and in which the pump member is in the form of a vane which can be swept to and fro through the pump chamber.

7. A method as claimed in Claim 6 in which the pump includes a plurality of arcuate pump chambers and in which the pump member is in the form of a corresponding plurality of vanes which can be swept to and fro through the ) respective pump chambers.

8. A method as claim in any one of Claim 1 to Claim 5 inclusive in which the pump is a squeeze pump, the pump chamber being conduit means for the fluid and the pump member being a squeeze member arranged to squeeze the conduit means. i

9. A wave action pumping installation for fluid suitable for location in association with a body of water undergoing wave action, the pumping installation including WO 00/70218 PCT/IB00/00627 25 a pump including a pump chamber, a reciprocating pump member reciprocal to and fro to effect pumping and valve means for controlling flow of fluid toward and from the pump chamber; biassing means for biassing the pump member in a predetermined direction toward a starting condition; a buoyancy member having buoyancy in water, and being connected to the pump member cyclically to drive the pump member from the starting condition when the buoyancy member is lifted by wave action in use.

10. A pumping installation as claimed in Claim 9 in which said buoyancy ) member is a primary buoyancy member, in which the biassing means includes a secondary buoyancy member having a predetermined buoyancy which is smaller than the buoyancy of the primary buoyancy member; the primary and secondary buoyancy members being connected to a lever at opposed sides of a fulcrum of the lever, the lever being drivingly connected to the pump member. i

11. A pumping installation as claimed in Claim 9 in which the biasing means includes a counterweight arranged only partially to counteract the effect of the buoyancy member.

12. A pumping installation as claimed in any one of Claim 9 to Claim 11 inclusive in which the pump is an arcuately reciprocal vane pump, the pump WO 00/70218 PCT/IB00/00627 26 chamber being an arcuate pump chamber and the pump member being a vane arcuately pivotal to and fro in the pump chamber.

13. A pumping installation as claimed in any one of Claim 9 to Claim 11 inclusive in which the pump is a composite arcuately reciprocal vane pump, which 5 includes a plurality of arcuate pump chambers and a corresponding plurality of pump members in the form of vanes respectively arcuately pivotal to and fro in the respective pump chambers.

14. A pumping installation as claimed in any one of Claim 9 to Claim 11 in which the pump is a squeeze pump, the pump chamber being a conduit means ) for the fluid and the pump member being a squeeze member arranged to squeeze the conduit means.