TECHNICAL FIELD

[0001] This invention relates to extraction of energy from wave motion, and more particularly to a wave energy conversion system for harnessing wave energy from a body of water and converting the harnessed wave energy to pressurised fluid.

[0002] The invention has been devised particularly, although not necessarily solely, for harnessing wave energy and converting the harnessed wave energy to pressurised fluid for use in any appropriate way. The pressurised fluid may comprise a working fluid (such as water) within a closed loop system from which energy can be extracted, or it may comprise water drawn from the body of water itself. The pressurised fluid may, for example, be used to drive a turbine and the shaft power from the turbine used to generate electricity. In the former arrangement, energy extracted from the working fluid may be used to operate a reverse osmosis desalination unit to yield potable water. In the latter arrangement, the pressurised water may be fed to a reverse osmosis desalination unit to yield potable water.

BACKGROUND ART

[0003] The following discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application.

[0004] The Applicant has developed or at least proposed various systems for harnessing wave energy in a body of water and converting the harnessed wave energy to pressurised fluid which typically comprises water drawn from the body of water itself. Where the body of water comprises an ocean, seawater drawn from the ocean may be piped under high-pressure to shore for use. The high-pressure seawater may, for example, be used to drive a turbine and the shaft power from the turbine used to generate electricity. Further, the high-pressure seawater may be fed to a reverse osmosis desalination unit to yield potable water. In such an arrangement, the salt water concentrate exiting the desalination unit, which is still under pressure, may be fed to a turbine and the shaft power used to generate electricity. Typical examples are such wave energy conversion systems are disclosed in WO 2007/019640, WO 2008/052286, WO 2009/076712, WO 2009/076714 and WO 2010/115241. [0005] However, the provision of pipelines capable of piping the high pressure seawater to shore are expensive and are a high failure risk for any such wave energy project. Further, the cost of the pipeline may be a limiting factor for a wave energy project, as more energetic waves are more likely to occur the father offshore the wave energy capturing device is located.

[0006] It is against this background, and the problems and difficulties associated therewith, that the present invention has been developed.

SUMMARY OF INVENTION

[0007] According to a first aspect of the invention there is provided a wave energy conversion system for harnessing wave energy in a body of water and converting the harnessed wave energy to pressurised fluid, the wave energy conversion system comprising a unit including a buoyant structure responsive to wave motion, a pump and a tether adapted to be operably connected between the pump and a fixture below the unit whereby movement of the buoyant structure relative to the fixture in response to wave motion converts harnessed energy to pressurised fluid, the buoyant structure comprises a body arranged to accommodate a removable portion, the removable portion comprising the pump or apparatus operable by pressurised fluid.

[0008] The removable portion may be entirely received within the body.

[0009] Alternatively, the removable portion may be substantially received within the body, such that any negative effects on the hydrodynamic properties of the buoyant structure are minimised, thereby reducing negative effects on power conversion efficiency.

[0010] The body may be arranged to accommodate a plurality of removable portions.

[0011] Preferably, the removable portion is configured as a modular unit to be substantially received within the body. Where there are a plurality of removable portions, each is preferably configured as a modular unit to be substantially received within the body

[0012] Preferably, the body has at least one cavity for accommodating the removable portion. [0013] Where there are a plurality of removable portions, the body preferably has a plurality of cavities for accommodating the removable portions.

[0014] Preferably, the unit is afforded a plurality of pumps.

[0015] Preferably, the pump is incorporated into the modular unit or into a respective one of the modular units.

[0016] In one arrangement, the removable portion may comprise the pump for producing pressurised fluid and apparatus operable by the pressurised fluid.

[0017] In another arrangement, the removable portion may comprise the apparatus operable by the pressurised fluid.

[0018] In yet another arrangement, one of the modular units comprises pump(s) for producing pressurised fluid adapted to provide pressurised fluids to at least one other module. With such an arrangement, the apparatus operable by the pressurised fluid may be provided in the at least one other module.

[0019] Preferably, the apparatus operable by the pressurised fluid is adapted to generate electricity.

[0020] Preferably, the removable portion preferably also comprises apparatus operable by the pressurised fluid for the production of potable water.

[0021] Preferably, the removable portion also comprises apparatus for the generation of electricity and the production of potable water operable by pressurised fluid.

[0022] Preferably, one of the modular units comprises apparatus operable by pressurised fluid to generate electricity.

[0023] Preferably, one of the modular units comprises apparatus operable by pressurised fluid for production of potable water.

[0024] Preferably, one of the modular units comprises apparatus both for the generation of electricity and production of potable water operable by pressurised fluid.

[0025] Preferably, the buoyant structure comprises means for varying the buoyancy of the unit. [0026] Preferably, the buoyant structure has a buoyant condition to permit it to float on the surface of the body of water when the removable portion is installed in, and also removed from, the body.

[0027] Preferably, the tether has an end adapted to be connected to the fixture and wherein the tether is adapted to undergo movement towards the fixture for connection thereto.

[0028] Preferably, the wave energy conversion system comprises at least one further pump.

[0029] Preferably, where the system comprises a further pump it also comprises a further tether adapted to be operably connected between the further pump and a further fixture below the unit. Alternatively, there may be several pumps adapted for connection to a common fixture by a common tether.

[0030] Preferably, there are a plurality of pumps and a corresponding number of tethers, whereby each pump has a respective tether; for example, there may be two pumps and two tethers.

[0031] More preferably, there are a plurality of pumps arranged in groups, each group comprising a plurality of pumps connected to the same tether; for example, there may be two pumps sharing a common tether, or four pumps arranged in pairs, with each pair sharing a respective common tether.

[0032] Preferably, coupling engagement between the tether and the fixture is provided by a coupling assembly comprising first and second coupling portions, one of which is associated with the tether and the other is associated with the fixture.

[0033] Preferably, the coupling assembly is operable remotely.

[0034] Preferably, the first and second coupling portions comprise a male coupling portion and a corresponding female coupling portion.

[0035] Preferably, the male coupling portion is associated with the tether and the female coupling portion is associated with the fixture.

[0036] Preferably, the fixture comprises an anchor embedded in, or otherwise affixed to, the floor of the body of water. [0037] Alternatively, the fixture is buoyant and is operably connected with an anchor embedded in, or otherwise affixed to, the floor of the body of water.

[0038] Preferably, the tether associated with each pump is adapted to be coupled to the pump upon introduction of the removable portion into the body and also to be released from the pump to facilitate removal of the removable portion.

[0039] Preferably, the tether is adapted to be coupled to, and released from, the pump while the unit is floating on the water surface.

[0040] Where the body is arranged to have a configuration having a major and a minor axis, the aspect ratio, which represents the ratio of major to minor axis, is preferably between 1 and 5.

[0041] More preferably, the aspect ratio is between 3 and 4.

[0042] Preferably, in this arrangement there are at least two pumps and two associated tethers.

[0043] Preferably, the pump and tether combinations are positioned in spaced apart relation along the major axis.

[0044] Preferably, electricity is conveyed from the unit along one or more electrical reticulation lines.

[0045] Preferably, potable water is conveyed from the unit along one or more water reticulation lines.

[0046] Preferably, control cabling and service lines run with the reticulation lines.

[0047] Preferably, the reticulation lines, control cabling and service lines are arranged in a single umbilical or reticulation assembly comprising of at least two of, an electrical reticulation line, a water reticulation line, a control cable or a service line.

[0048] Preferably, the reticulation lines or umbilical for electricity and/or water run in a catenary descending to run along the floor of the body of water to a destination.

[0049] More preferably, the reticulation lines or umbilical run in a catenary to a floating mooring before descending to run along the floor of the body of water to a destination. [0050] Even more preferably, the reticulation lines or umbilical have distributed along their length a plurality of buoyancy modules arranged such that the reticulation lines or umbilical form a wave like arrangement between the unit and the floor of the body of water before running along the floor of the body of water to a destination.

[0051] Alternatively, the reticulation lines or umbilical for electricity and/or water may run to one of the tethers and then descend along the tether to run along the floor of the body of water to a destination.

[0052] Preferably, the reticulation lines or umbilical run in a catenary to the tether.

[0053] Even more preferably, the reticulation lines or umbilical run in a catenary to the tether, before descending along the tether through an axial passage within the tether.

[0054] Preferably, the action of the pumps can be controlled by limiting the input and output flows to the pump.

[0055] Preferably, the pumps are arranged in groups.

[0056] More preferably, the pumps are arranged in operational pairs

[0057] Preferably, the action of the pumps can be controlled by limiting the input and output flows to the pumps to allow for control of the relative yawing motion of the unit.

[0058] According to a second aspect of the invention there is provided a wave energy conversion system for harnessing wave energy in a body of water and converting the harnessed wave energy to pressurised fluid, the wave energy conversion system comprising a unit including a buoyant structure responsive to wave motion, a pump and a tether adapted to be operably connected between the pump and a fixture below the unit whereby movement of the buoyant structure relative to the fixture in response to wave motion converts harnessed energy to pressurised fluid, the unit comprises a body arranged to accommodate a plurality of removable portions containing plant adapted to harness wave energy, the removable portions comprising pump(s) or apparatus operable by pressurised fluid.

[0059] Preferably, the body has a plurality of cavities for accommodating a plurality of removable portions. [0060] Preferably, the pump is incorporated into a modular unit which provides one of the removable portions.

[0061] Preferably, the removable portions are of a uniform size and shape to allow the removable portions to be interchangeable.

[0062] Preferably, the removable portion comprises the pump(s) for producing the pressurised fluid and apparatus operable by the pressurised fluid.

[0063] Preferably, the apparatus operable by the pressurised fluid is adapted to generate electricity.

[0064] Preferably, at least one of the removable portions also comprises apparatus operable by the pressurised fluid for the production of potable water.

[0065] Preferably, at least one of the removable portions also comprises apparatus for the generation of electricity and the production of potable water operable by pressurised fluid.

[0066] Preferably, one of the modular units comprises pump(s) for producing pressurised fluid adapted to provide pressurised fluids to other modules.

[0067] Preferably, one of the modular units comprises apparatus operable by pressurised fluid to generate electricity.

[0068] Preferably, one of the modular units comprises apparatus operable by pressurised fluid for production of potable water.

[0069] Preferably, one of the modular units comprises apparatus both for the generation of electricity and production of potable water operable by pressurised fluid.

[0070] In one arrangement the body is circular in plan, with the plurality of cavities arranged in a circular pattern.

[0071] Preferably, with the body in a circular arrangement the cavities are circumferentially arranged.

[0072] Preferably, the modular units are adapted to be retrieved and installed into the body whilst the body is floating in a body of water. [0073] Preferably, the modular units are of a common size and shape, such that they are operably interchangeable.

[0074] Preferably, the action of the pumps can be controlled by limiting the input and output flows to the pump.

[0075] Preferably, the pumps are arranged in groups.

[0076] More preferably, the pumps are arranged in operational pairs.

[0077] Preferably, the action of the pumps can be controlled by limiting the input and output flows to the pumps to allow for control of the relative yawing motion of the unit.

[0078] According to a third aspect of the invention there is provided a wave energy conversion system for harnessing wave energy in a body of water and converting the harnessed wave energy to pressurised fluid, the wave energy conversion system comprising a unit providing a buoyant structure responsive to wave motion, a plurality of pumps, and a tether adapted to be operably connected between the pumps and a fixture below the unit, whereby movement of the buoyant structure relative to the fixture in response to wave motion converts harnessed energy to pressurised fluid, the buoyant structure comprising a body arranged to accommodate at least one removable portion, the removable portion(s) comprising the pump(s) or apparatus operable by pressurised fluid, the pumps being disposed angularly towards the tether and mounted for angular movement with respect to each other, whereby force acting on the pumps through the tether and subsequent extension and contraction of the pump piston causes the pumps to swing arcuately at their lower ends as the buoyant structure responds to wave motion.

[0079] Preferably, the outward swinging movement of the pumps progressively increases the loading on the pumps as the buoyant structure rises, thereby increasing the force exerted on the pump which can translate to an increase in piston force with stroke.

[0080] Preferably, the pumps are coupled to the tether through intermediate tethers. [0081] The intermediate tethers may comprise a bridle.

[0082] In accordance with a fourth aspect of the invention there is provided a wave energy conversion system for harnessing wave energy in a body of water and converting the harnessed wave energy to pressurised fluid, the wave energy conversion system comprising a unit providing a buoyant structure responsive to wave motion, a plurality of pumps, and a tether adapted to be operably connected between the pumps and a fixture below the unit, whereby movement of the buoyant structure relative to the fixture in response to wave motion converts harnessed energy to pressurised fluid, the buoyant structure comprising a body arranged to accommodate at least one removable portion, the removable portion(s) comprising the pump(s) or apparatus operable by pressurised fluid, the pumps being disposed angularly towards the tether and mounted for angular movement with respect to each other, whereby force acting on the pumps through the tether and subsequent extension and contraction of the pump piston causes the pumps to swing arcuately at their lower ends as the buoyant structure responds to wave motion wherein initial angle of the pumps is variable thereby allowing the initial loading of the pumps to be changed in response to wave conditions.

[0083] Preferably, the buoyant structure is afforded a plurality of pumps.

[0084] Preferably, the initial loading of the pumps is changable in response to wave conditions.

[0085] Preferably, the initial angle of the pump is controlled through slidable motion of the pump with respect to the body.

[0086] Preferably, each of the pumps can have its initial angle controlled to control the initial loading on the pump.

[0087] Preferably, the action of the pumps can be controlled by limiting the input and output flows to the pump.

[0088] Preferably, the pumps are circumferentially arranged such that there are equal loadings on the pumps at the start of a stroke cycle.

[0089] Preferably, the pumps are arranged in groups.

[0090] More preferably, the pumps are arranged in operational pairs.

[0091] Preferably, the action of the pumps can be controlled by limiting the input and output flows to the pumps to allow for control of the relative yawing motion of the unit. [0092] In accordance with a fifth aspect of the invention there is provided a wave energy conversion system for harnessing wave energy in a body of water and converting the harnessed wave energy to pressurised fluid, the wave energy conversion system comprising a unit providing a buoyant structure responsive to wave motion, at least four circumferentially arranged pumps, and a tether adapted to be operably connected between the pumps and a fixture below the unit, whereby movement of the buoyant structure relative to the fixture in response to wave motion converts harnessed energy to pressurised fluid, the buoyant structure comprising a body arranged to accommodate at least one removable portion, the removable portion(s) comprising the pump(s) or apparatus operable by pressurised fluid, wherein the pumps are arranged in orthogonally opposed operational pairs, each pair being connected to a common tether, and arranged to have a different size to the opposing pair, thereby allowing the capture of relative tipping motion of the unit in response to wave action.

[0093] Preferably, the difference in size of the pumps relates to the annulus size of the piston.

[0094] Preferably, the size of the pumps is chosen based upon the expected sea state at the installation area.

[0095] Preferably, the action of the pumps can be controlled by limiting the input and output flows to the pump.

[0096] Preferably, the pumps are circumferentially arranged such that there are equal loadings on the pumps at the start of a stroke cycle.

[0097] Preferably, the pumps are arranged in groups.

[0098] More preferably, the pumps are arranged in operational pairs.

[0099] Preferably, the action of the pumps can be controlled by limiting the input and output flows to the pumps to allow for control of the relative yawing motion of the unit.

BRIEF DESCRIPTION OF THE DRAWINGS

[00100] Further features of the present invention are more fully described in the following description of several non-limiting embodiments thereof. This description is included solely for the purposes of exemplifying the present invention. It should not be understood as a restriction on the broad summary, disclosure or description of the invention as set out above. The description will be made with reference to the accompanying drawings in which:

Figure 1 is a perspective view of a first embodiment of a wave energy conversion system according to the invention;

Figure 2 is a schematic view of a unit forming part of the first embodiment, the unit moored alongside a structure in readiness to receive a module to complete assembly of the unit;

Figure 3 a schematic side view illustrating installation of the module to complete assembly of the unit;

Figure 4A is a front view of the assembled unit of Figure 3;

Figure 4B is a schematic view, on a larger scale, of a thruster module adapted to be mounted on the assembled unit;

Figure 5 is a front view of the first embodiment, with the unit operably connected to an anchor on the sea floor, ready for connection of reticulation lines or assemblies;

Figure 6 is a schematic view illustrating connection of reticulation lines on the unit to a floating tethered mooring;

Figure 7 is a schematic view illustrating the first embodiment arranged in operation;

Figure 8 is a schematic view illustrating the active buoyancy control of the unit in operation to cause the unit to tilt;

Figure 9 is a schematic side view of a second embodiment of a wave energy conversion system according to the invention, wherein a removable portion comprises two angularly disposed pumps arranged to engage a single tether;

Figure 10 is a schematic view of a third embodiment of the invention, wherein the orthogonally arranged pumps are arranged to move radially.

Figure 11 is a schematic view of a portion of a fourth embodiment of a wave energy conversion system according to the invention, wherein the body is afforded a plurality of cavities for accommodating a plurality of removable portions; Figure 12 is schematic side view of a fifth embodiment of a wave energy conversion system according to the invention, wherein the unit comprises four pumps arranged in opposing pairs;

Figure 13 is schematic side view of a seventh embodiment of a wave energy conversion system according to the invention, wherein the body is arranged in a substantially circular plan;

Figure 14 is schematic side view of a eighth embodiment of a wave energy conversion system according to the invention, wherein the body is substantially circular in plan and has a three circumferentially spaced pumps with equal angles there between;

Figure 15 is schematic side view of a ninth embodiment of a wave energy conversion system according to the invention, wherein circumferentially spaced pumps are arranged in operational pairs orthogonally;

Figure 16 is an upper schematic view of embodiment shown in Figure 15;

Figure 17 is schematic side view of a tenth embodiment of a wave energy conversion system according to the invention, wherein the orthogonally arranged pumps have a different annular size;

Figure 18 is schematic side view of an eleventh embodiment of a wave energy conversion system according to the invention, wherein the orthogonally arranged pumps are angularly disposed arranged to engage a single tether;

Figure 19 is schematic side view of a twelfth embodiment of a wave energy conversion system according to the invention, wherein the orthogonally arranged pumps are angularly disposed and subsequent extension of the pumps causes the pumps to swing outwardly;

Figure 20 is schematic side view of thirteenth embodiment of a wave energy conversion system according to the invention, wherein the body comprises a plurality of cavities, the removable portions being configured as modules;

Figure 21 is a schematic view of the fourteenth embodiment of a wave energy conversion system according to the invention, wherein each module is arranged to have a common size and shape; Figure 22 is a schematic view of the fifteenth embodiment of a wave energy conversion system according to the invention, wherein incorporated within the unit is a propulsion system;

Figure 23 is a top view of the wave energy conversion system of Figure 22;

Figure 24 is a schematic view of a sixteenth embodiment of the wave energy conversion system, with a reticulation line assembly running alongside a tether;

Figure 25 is a schematic view of a seventeenth embodiment of the wave energy conversion system with a reticulation line assembly running within a tether;

Figure 26 is a schematic view of an eighteenth embodiment of the wave energy conversion system with a reticulation line assembly, running in a catenary to the sea floor;

Figure 27 is a schematic view of a nineteenth embodiment of the wave energy conversion system, with a reticulation line assembly having buoyancy modules arranged along its length, allowing the assembly to run to the sea floor in a wave like arrangement; and

Figure 28 is a schematic view of a buoyant fixture operably attached to a tether of the wave energy conversion system in accordance with a twentieth embodiment of the invention.

[00101] In the drawings like structures are referred to by like numerals throughout the several views. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the present invention.

DESCRIPTION OF EMBODIMENTS

[00102] The embodiments shown in the drawings are each directed to a wave energy conversion system 100 according to the invention for deployment in a body of water 102 having a surface 104 and a floor 106 (see figure 5). The body of water 102 is typically at sea in which case the floor 106 comprises the sea bed. In use, the wave energy conversion system 100 is deployed at an installation site 108 at sea and, as necessary, subsequent recovery of the wave energy conversion system is effected from the installation site. [00103] Referring to Figures 1 to 10, the first embodiment of the wave energy conversion system 100 comprises a unit 110 which provides a buoyant structure responsive to wave motion. The unit 110 is of modular construction comprising a first portion 112 and at least one removable portion 114. The first portion 112 comprises a body 116 having a cavity 118 for accommodating the removable portion 114. The removable portion 114 is configured as a module to be received in the cavity 118 within the body 116.

[00104] The body 116 is configured as a shell 120 having an outer surface 122 which provides the buoyant structure 124. The shell 120 incorporates a cover 126 which is selectively removable for access to the cavity 118. The outer surface 122 is configured to be coupled with the body of water when in a submerged condition to respond to wave motion. In the arrangement illustrated in Figure 1 , the buoyant structure 124 is in a submerged condition with the outer surface 122 coupled with the body of water to respond to wave motion, although the body of water is not depicted in that drawing.

[00105] In the arrangement illustrated, the body 116 is of an elongate configuration in plan, comprising a major axis and a minor axis. In this embodiment the body has a length along the major axis of 30 metres and a width about the minor axis of 10 metres. However, in accordance with preferred embodiments of the invention, the aspect ratio is within the range of between 1 :1 and 5:1. More preferably, the aspect ratio is within the range 3:1 to 4:1.

[00106] Other configurations for the body 116 are, of course, possible, including for example a configuration which is substantially circular (an aspect ratio of 1 :1 ) when viewed on plan, as well as various configurations described and illustrated in the Applicant's prior art cases as referred to above.

[00107] One advantageous aspect of the elongate configuration is it allows the body 116 to be moored alongside a fixed or floating structure 127 such as a structure 128, as depicted in Figure 2, capable of constraining the body's motion, thereby allowing access to the removable portions 114 to be affected by a crane or similar lifting device.

[00108] Depicted schematically in Figure 2, the body 116 is moored alongside a structure 128 with the major axis extending along the structure and the minor axis transverse to the structure 128. This arrangement reduces the reach required from the structure 128 for installation of the removable portion 114 into the cavity 118 within the body 116. Installation and recovery of the removable portion 114 with respect to the body 116 is normally performed using a lifting arrangement which would likely comprise a crane having a boom from which a haul line would extend. Having regard to costs, it is desirable to limit the size of the crane, and an arrangement which limits the necessary boom length is therefore advantageous. This arrangement, which reduces the reach required for installation/and or removal of the removable portion 114, is consistent with this approach.

[00109] Furthermore, with the modular construction of the unit 110, there is only a requirement for a facility to lift the removable portion 114 rather than the overall unit 110.

[00110] As shown in Figure 3, the removable portion 114 incorporates a pumping system 130 operable in response to movement of the buoyant structure 124 relative to the sea floor 106 to generate pressurised fluid. The pumping system 130 comprises two linear actuating pumps 132, each adapted to be connected by tether 134 to the sea floor 106.

[00111] Each pump 132 has an extended condition and a contracted condition, with the effective length of the pump 132 increasing upon movement from the contracted condition to the extended condition and the effective length of the pump 132 decreasing upon movement from the extended condition to the contracted condition.

[00112] Each pump 132 comprises a reciprocating piston pump having a pump body 136 defining a cavity and a piston comprising a piston head (not shown) and a rod 138, the piston being slidably and sealingly mounted with respect to the body for reciprocatory movement with respect to the cavity.

[00113] With this arrangement, the piston and cavity cooperate to define a pumping chamber (not shown) adapted to undergo expansion and contraction in response to reciprocatory movement of the piston with respect to the cavity.

[00114] In alternative arrangement, as will be appreciated such a pump can define two pumping chambers, wherein fluid may be drawn regardless of direction of movement of the piston.

[00115] In this embodiment, the pumping system 130 comprises a closed circuit around which a working fluid circulates, the arrangement being that the pumps 132 pressurise the working fluid to provide the pressurised fluid. The working fluid may comprise any appropriate fluid; for example, a liquid such as water or any other suitable type of substantiality incompressible fluid.

[00116] In an alternative arrangement, the pressurised fluid may comprise fluid flowing through an open circuit, being seawater drawn from the body of water 102.

[00117] The pump 132 has an inlet (not shown) for receiving low pressure fluid in the closed circuit and an outlet (not shown) for discharging said fluid under pressure (thereby providing the pressurised fluid in the circuit). The piston rod 138 extends from the piston outwardly from the pump body 136 and is adapted for releasable connection to the respective tether 134.

[00118] In the arrangement shown, the outer end of each piston rod 138 is provided with a coupling element 140 adapted to receive a releasable mating coupling element 142 provided on the top end of the respective tether 134. The top ends of the tethers 134b are readily accessible to permit workers on the unit 110 to connect the coupling elements 142 provided on the top ends of the tethers 134b to the mating coupling elements 140 on the bottom end of the piston rods 138.

[00119] The pumps 132 are accommodated mostly within the confines of the buoyant structure 124 but protrude somewhat beneath, as shown in the drawings. This arrangement as shown is to limit negative hydrodynamic effects on the buoyant structure 124. As will be appreciated by a person skilled in the art, the hydrodynamic drag acting on the buoyant structure 124 reduces the amount of energy which is converted as a result of wave motion and therefore should be avoided where possible. As shown in Figure 4, the system 100 comprises thruster modules 145, configured to be detachably mounted to the unit 110. A plurality of thruster modules 145 cooperate together to form a propulsion system 146 that can be used to manoeuvre the unit 110.

[00120] As shown, the removable portion 114 incorporates a central housing section 144 which can accommodate a first apparatus (not shown) communicating with the closed circuit and operable by the pressurised fluid. In this embodiment the first apparatus is operable by the pressurised fluid to generate electricity, thereby extracting energy from the pressurised fluid as referred to above. The first apparatus comprises a hydraulic motor or turbine operable by the pressurised fluid, and an electric generator adapted to be driven by the hydraulic motor or turbine. Of course, the first apparatus may comprise any other appropriate arrangement operable to extract energy from the pressurised fluid.

[00121] In accordance with other preferred embodiments, the central housing section 144 further accommodates a second apparatus operable by the pressurised fluid. The second apparatus may, for example, provide for the production of potable water. This may involve a reverse osmosis desalination system operating to provide potable water. In this embodiment, energy of the pressurised fluid is transferred to pressurise a separate stream of seawater to feed the reverse osmosis desalination system. Other arrangements are, of course, possible; for example, where the working fluid comprises water drawn from the body of water, the pressurised water may be fed directly to a reverse osmosis desalination system to yield potable water.

[00122] Electricity generated by the first apparatus is delivered to an outlet 150 mounted on the exterior of the body 116. Further, potable water produced by the reverse osmosis desalination system is delivered to an outlet 152 mounted on the exterior of the body 116. The two outlets 150, 152 are co-located on the body 116.

[00123] The electricity may be conveyed from the unit 110 along one or more electrical reticulation lines connected to the electrical outlet 150. Further, potable water may be conveyed from the unit 110 along one or more water reticulation lines connected to the water outlet 152.

[00124] The electrical reticulation lines and water reticulation lines are not shown separately in the drawings but rather as depicted as a common reticulation line assembly 154 forming part of a reticulation system 156. The common reticulation line assembly 154 may run as a catenary to a submerged yet buoyant tethered mooring 158 (See Figure 1) and descends to run along the sea bed 06 to a destination. The tethered mooring 158 comprises a submerged float 160 connected to an anchor 162 on the sea floor 106 by mooring tether 164.

[00125] The common reticulation line assembly 154 places the unit 110 in communication with the site at which the electricity and potable water is recovered for use or distributed further. The site may be an onshore site or an offshore site such as an offshore oil and gas platform, a moored vessel, or any other stationary offshore entity having an energy and/or water requirement. [00126] As mentioned earlier, the tethers 134 are connected at their top ends to the piston rods 138 of the pumps 132. With this arrangement, actuation of the pumps 132 through regulation of fluid pressure therein can be used to raise and lower the tethers 134 prior to connection of the tethers 134 to sea floor 106. This feature is particularly useful during deployment of the wave energy system 100 at the installation site 108. The tether 134 may also be arranged to comprise a swivel portion, therein allowing relative rotation of its two ends.

[00127] The tethers 134 are anchored to the sea floor 106 by way of fixtures 166 in the sea bed. The fixtures 166 each comprise an anchor 168 embedded in the sea floor 106. The anchor 168 may be of any appropriate form well understood by a person skilled in the art. The anchors 168 are installed in the sea floor 106 at appropriate locations prior to delivery of the unit 110 to the installation site 108.

[00128] Coupling engagement between each tether 134 and the respective fixture 166 is adapted to be selectively releasable to facilitate subsequent recovery of the unit 110 from the installation site.

[00129] The coupling engagement is provided by a coupling assembly 167 comprising first and second coupling portions 167a, 167b, one of which is associated with the respective tether 134 by being attached to the bottom end 134a thereof, and the other of which is associated with the respective anchor 168 by being secured thereto. In the arrangement shown, the first coupling portion 167a is configured as a male coupling portion and the second coupling portion 167b is configured as a mating female coupling portion.

[00130] The coupling assembly 167 may be of any appropriate form, a typical example of which might comprise a subsea connector of the type disclosed in US Patent 8,166,620, the contents of which are incorporated herein by way of reference. Other coupling arrangements can, of course, be used.

[00131] The buoyant structure 124 has provision for active buoyancy control, whereby different sections of the buoyant structure may be caused to descend in the water at different times. In this embodiment, the buoyant structure 124 incorporates chambers (not shown) which can be selectively flooded or evacuated to tilt one or both ends of the buoyant structure downwardly, as shown in Figure 8. [00132] Further, the chambers may be selectively flooded or evacuated to vary the hydrodynamic properties of the buoyant structure 124 in response to wave motion, in a manner similar to the Applicant's prior art applications.

[00133] If repair or maintenance is required to componentry on-board the removable portion 1 14, the latter can be removed from the body 116 through the upper end of the cavity 118 in a procedure which is a reverse of the procedure described and illustrated in Figure 3.

[00134] From the foregoing, it is evident that the first embodiment provides a wave energy conversion system which can deliver reticulated outputs in the form of electricity and potable water.

[00135] Further, there is integration of wave energy conversion, electrical generation and production of potable water into one unit, thereby enabling the reticulated output(s) to be sent to users not necessarily onshore. More particularly, the reticulated output(s) can be sent to users at offshore locations, including for example offshore oil and gas platforms, moored vessels, or any other stationary offshore entity having an energy and/or potable water requirement.

[00136] Still further, while there is integration of wave energy conversion, electrical generation and production of potable water into one unit, critical inner workings, such as pumps and hydraulic to electrical conversion equipment and reverse osmosis equipment, can be removed for both preventative maintenance and unscheduled service without requiring the complete unit 110 to be removed from the water. Rather, the body 116 providing the buoyant structure 124 can remain in the water, and the removable portion 114 incorporating the critical workings can be removed.

[00137] Further, the removable portion 114 can be replaced in the same operation to allow the system to continue to operate whilst repairs and maintenance are affected on the first unit. As will be appreciated this therefore allows significant time and cost savings, as a replacement removable portion 114 can be fitted directly after the removal of removable portion 114 requiring service.

[00138] The first embodiment of the wave energy conversion system 100 has two tethers 134. Other arrangements are possible. [00139] Figure 9 shows a second embodiment of the present invention, wherein a removable portion 114 comprises two pumps 132 arranged to engage a single tether 134. The single tether 134 is connected to the two pumps 132 via intermediate tethers 170. The two pumps 132 are disposed angularly such that their longitudinal axes (representing their lines of action in moving between extended and contracted conditions) are inclined to the vertical and directed towards the common tether 134.

[00140] Each pump 132 is supported within the removable portion 114 in a manner which permits angular movement of the pump with respect to the unit 110 to accommodate pitching and rolling motion of the buoyant structure 124. The mounting arrangement comprises a gimbal assembly (not shown) allowing the pump to move angularly as required. With this arrangement, the two pumps can swing towards and away from each other.

[00141] The two intermediate tethers 170 are disposed angularly with respect to each other, as shown in Figure 9, and function as a bridle coupling the two pumps 132 to the tether 134. With this arrangement, force exerted on the pumps 132 through the tether 134 and subsequent extension and contraction of the pump piston 138 causes the pumps 132 to swing arcuately at their lower ends as the buoyant structure 124 responds to wave motion. This arcuate swinging movement corresponds to a progressive reduction in the angle between the two intermediate tethers 170 as the buoyant structure 124 rises. The arcuate movement of the pumps 132 progressively increases the loading on the pumps as the as the buoyant structure 124 rises, thereby increasing the force exerted on the pump, which is translated to an increase in piston force with stroke, which can be used to advantage in the a pumping system 130.

[00142] This feature is applicable to any embodiment having a plurality of pumps coupled to a common tether.

[00143] In the first embodiment of the wave energy conversion system 100, the relative location of the pumps 132 within the body is fixed.

[00144] In accordance with a third embodiment of the invention, which is .shown in Figure 10 there is provided a plurality of pumps 132 arranged in an angularly disposed manner similar to the manner described in the second embodiment differing in that the end points of the pumps 132 are mounted to be radially movable within the body 116. More particularly, the pumps 132 are disposed in a circumferential array and the pumps are selectively movable with respect to the body 116 in a radial direction with respect to the circumferential array, thereby shifting each pump laterally inwardly or outwardly in radially with respect to the circumferential array. With this arrangement, the end points of the pumps 132 are radially movable with respect to the body, allowing the initial angle between the pumps to be controlled, therein allowing changes in the relative force acting on each pump 132 in response to wave motion.

[00145] The Applicant has found that such a configuration allows the response of the system to be adapted in response to expected wave motion, therein reducing wear on the system.

[00146] The ends of the pumps may be slidably mounted or in an alternative arrangement may be controlled through the use of a reciprocating thread or by linear actuator.

[00147] In the first embodiment of the wave energy conversion system 100, the body 116 is afforded a cavity 118 to accommodate a removable portion 114. Other configurations are possible.

[00148] In accordance with a fourth embodiment of the invention, as shown in Figure 11 , the body 116 is afforded a plurality of cavities 118 to accommodate a plurality of removable portions 114.

[00149] The arrangement as shown allows for each pump 132 or apparatus operable by pressurised fluid such as central housing section 144 to be installed separately within the body. Beneficially this arrangement allows for an even greater reduction in the lifting capacity to replace the removable portions 114 due to their substantially reduced size. Further, if any one of the removable portions 114 needs to be replaced for some unscheduled reason, the affected removable portion 114 only need be replaced.

[00150] In the first embodiment of the wave energy conversion system 100, the unit 110 is afforded a pair of pumps. Other configurations are possible.

[00151] In accordance with a fifth embodiment of the invention, as shown in Figure 12, the unit comprises four pumps arranged in opposing pairs toward each elongate end of the body 116. As discussed above in relation to the second embodiment, the pumps 132 may be arranged to engage intermediate tethers 170 before engaging a single tether 132. Further, each opposing pair of pumps may engage an intermediate tether before engaging a tether 134, such that the unit has two tethers engaging the four pumps.

[00152] The opposing pairs of pumps 132 are also arranged to be disposed angularly such that their longitudinal axes (representing their lines of action in moving between extended and contracted conditions) are inclined to the vertical and directed towards the common tether 134.

[00153] In the fifth embodiment of the wave energy conversion system 100, the unit 110 is described as being afforded four pumps. Other configurations are possible, such that the unit may be afforded a single pump or a plurality of pumps.

[00154] In the first embodiment of the wave energy conversion system 100, the input and output flows of the pumps 132 are unregulated. Other arrangements are possible.

[00155] In accordance with a sixth embodiment of the invention, (which is not shown), the pumping system 130 includes a means for controlling input and output flow of the respective pumps 132.

[00156] The means for controlling input and output flow effectively allow the selective control of the stiffness of the respective pumps 132. The Applicant has found that such an arrangement allows for the more efficient conversion of wave energy through the ability to better capture pitching and rolling motions of the buoyant structure 124 in response to wave motion.

[00157] In the first embodiment of the wave energy conversion system 100, the body 116 is of an elongate configuration in plan. Other configurations are possible.

[00158] In accordance with a seventh embodiment of the invention, as shown in Figure

13, the body 116 is substantially circular in plan. The arrangement as shown having a plurality of pumps 132 and a single tether 134, with the single tether being common to the pumps. The single tether 134 is connected to the pumps 132 via intermediate tethers 170. Other arrangements such as a single pump are also possible.

[00159] In accordance with an eighth embodiment of the invention, as shown in Figure

14, there are three pumps 132 coupled to a common tether 134 by intermediate tethers 170. The three pumps 132 are circumferentially spaced, with equal angles there between. [00160] In accordance with a ninth embodiment of the invention, as shown in Figures 15 and 16, there are four pumps 132. In this arrangement the cavity within the body 116 is of an X-configuration, as depicted in Figure 16, to accommodate a module (not shown) configured to support the pumps 132 in their spatial arrangement.

[00161] In this embodiment, the operational pairs 214 and 216 comprise pumps 132 of equal piston size. Other configurations are possible.

[00162] In accordance with a tenth embodiment of the invention, as shown in Figure 17, the operational pairs 214 and 216 comprise pumps 132 of different annular sizes. Such an arrangement is particularly useful for capturing pitching and rolling motions (relative movement orthogonal to wave direction) to be captured by the wave energy conversion system.

[00163] Further, by arranging the pumps 132 in operational pairs 214 and 216 having different sizes, as well as an arrangement similar to as described in accordance with the previous embodiment wherein flow control of the inlet and outlet of the pumps occurs, the Applicant has found that it is possible to effectively tune the operation of the unit 110 in response to wave conditions. In lower sea states where less energy may be extracted, the pump of operational pair 214 with a smaller size is arranged to turn such that the operational pair 214 are parallel to the direction of which the waves are approaching the unit 110. In higher sea states, the pumps of operational pair 216 with a larger size is able to be turned into the direction of wave travel, thereby allowing a greater amount of energy to be extracted in response to wave motion.

[00164] In accordance with an eleventh embodiment of the invention, as shown in Figure 18, there are a plurality of pumps 132; specifically, four pumps in the arrangement shown. The plurality of pumps 132 are disposed angularly such that their longitudinal axes (representing their lines of action in moving between extended and contracted conditions) are inclined to the vertical and directed towards the common tether 134. Because the body 116 is substantially circular in plan, the pumps 132 are circumferentially spaced with respect to each other at equal angular intervals.

[00165] Such an arrangement is beneficial as it reduces the stroke length of the pumps in response to the movement of the buoyant structure is reduced.

[00166] The pumps 132 are arranged in operational pairs arrayed orthogonally. In the arrangement shown, there are four pumps 132 arranged in two sets of operational pairs 214 and 216, with all pumps 132 connected to a single tether 134 via intermediate tethers 170.

[00167] Other tether configurations are possible; for example, each operational pair of pumps 132 may engage a respective intermediate tether 170 and a respective tether 134. Such an arrangement allows for better energy capture by the wave energy conversion system 100.

[00168] The Applicant has found that such an arrangement is of particular benefit in capturing pitching motion of the unit 110 in response to wave motion. With this arrangement, the operational pairs 214 and 216 allow the response of the unit 110 to be directional in nature.

[00169] In an alternative arrangement, the unit 110 includes means for controlling the input and output flow of the pumps 132 arranged to control opposing pumps as operational pairs 214 and 216. Each operational pair is arranged such that the stiffness of each respective pump 132 of the operational pair 214, 216 are equal.

[00170] In accordance with a twelfth embodiment of the invention, as shown in Figure 19, there are a plurality of pumps 132; specifically, four pumps in the arrangement shown. The pumps are mounted for angular movement, typically by way of gimbal arrangements. With such an arrangement, the pumps 132 can assume conditions in which they are angularly disposed such that their longitudinal axes (representing their lines of action in moving between extended and contracted conditions) are inclined to the vertical and directed towards the common tether 134. Because the body 116 is substantially circular in plan, the pumps 132 are circumferentially spaced with respect to each other at equal angular intervals. With this arrangement, force exerted on the pumps 132 through the tether 134 and subsequent extension and contraction of the pump piston 138 causes the pumps 132 to swing outwardly at their lower ends as the buoyant structure 124 rises. This outward swinging movement corresponds to a progressive reduction in the angle between the intermediate tethers 170 as the buoyant structure 124 rises. This outward swing movement of the pumps 132 progressively increases the loading on the pumps as the as the buoyant structure 124 rises, thereby increasing the force exerted on the pump can translate to an increase in piston force with stroke, which can be used to advantage in the a pumping system 130. [00171] In one arrangement, the angle of deflection of the pumps is changed in accordance with the sea state the buoyant structure is experiencing. This allows control over the dynamic response of the buoyant structure 124 by controlling the inclination angle of the pump 132 when the pump 132 is in its contracted state. As the loading on the pump 132 increases with the angle between the pumps 132, the initial load on the pumps 132 can be controlled in this manner.

[00172] In an alternative arrangement, the unit 110 includes means for controlling the input and output flow of the pumps 132 arranged to control opposing pumps as operational pairs 214 and 216. Each operational pair is arranged such that the stiffness of each respective pump 132 of the operational pair 214, 216 are equal.

[00173] The Applicant has discovered it is possible to effectively control the relative yawing motion of the unit 110. By arranging the pumps 132 in operational pairs 214 and 216, as was described in relation to several previous embodiments, and by controlling the input and/or output paths of the operational pairs it is possible to control the dynamic force absorbed by the operational pair In this manner the Applicant has found that it is possible to 'steer' the unit 110 as the operational pair 214 and 216 with the lowest effective resistance will tend to turn toward the wave front direction. By varying which operational pair 214 and 216 has the lowest resistance, effective steering can be achieved provided that the tether comprises a swivel portion.

[00174] In accordance with the preceding embodiments of the invention the wave energy conversion system 100 has comprised a unit 110 which provides a buoyant structure 124 responsive to wave motion. The unit 110 is of modular construction comprising a first portion 112 and one or more removable portions 114. Other configurations are possible.

[00175] In accordance with a thirteenth embodiment of the invention, which is shown in Figure 20, the first portion 112 comprises a body 116 having a plurality of cavities 118 for accommodating the removable portions 114. The removable portions 114 are each configured as a module 176 to be received in the cavities 118 within the body 116.

[00176] The body 1 16 is configured as a shell 120 having an outer surface 122 which provides the buoyant structure 124. The shell 120 incorporates a cover 126 which is selectively removable for access to the cavities 118. The outer surface 122 is configured to be coupled with the body of water when in a submerged condition to respond to wave motion.

[00177] In one arrangement in accordance with the features of the fifth embodiment, the cavities are 118 circumferentially spaced with respect to each other at equal angular intervals.

[00178] Other arrangements are also possible; for example, in accordance with the features described in the first embodiment, wherein the body 116 is of an elongate configuration, then the cavities 118 can be arranged in two circumferentially spaced groups arranged at either end of the body 116.

[00179] In accordance with the preceding embodiments of the invention the wave energy conversion system 100 has been described with the body 116 featuring cavities 118 arranged to accommodate a removable portion 114. Other configurations are also possible.

[00180] In accordance with a fourteenth embodiment of the invention, which is shown in Figure 21 , the removable portions 114 are arranged as modules 176. Each module 176 is arranged to have a common size and shape. This arrangement therein allows the modules 176 to be operably interchangeable with each other.

[00181] Such an arrangement is particularly beneficial as it allows the wave energy conversion system 100 to be deployed to generate different outputs dependent upon which modules 176 are presently installed. Therein the output of the system 100 can be changed and tailored to meet demand for the reticulated outputs.

[00182] In this arrangement, one of the modules 176 comprises a pump 132 for the generation of pressurised fluid in response to relative movement of the body 116 in response to wave motion. The pressurised fluid generated by the pump 132 being arranged to be passed to other modules 176 within the body 116.

[00183] Other modules 176 comprise apparatus operable by pressurised fluid such as apparatus for electrical generation comprising a hydraulic power take off motor or apparatus for generation of potable water.

[00184] Each of the generation modules 176, being arranged to provide a reticulated output to the common reticulation line assembly 154. [00185] From the foregoing, it is evident that the respective embodiments each provides a wave energy conversion system 100 which can deliver reticulated outputs in the form of electricity and potable water. Additionally, due to the modular nature of the construction used, it is possible to adapt the output produced by the system in response to demand, for example, if for some reason additional potable water was required, an electrical generation module could be removed from the unit 110 and replaced with an additional potable water module.

[00186] Further, the modular nature of the construction used allows the unit 110 to continue to operate even in circumstances where a particular module 176 may have failed. For example, where an electrical generation module has failed or is required to have maintenance, the associated potable water module could continue to operate until such time as the maintenance or repair work can be undertaken.

[00187] In other arrangements, the plurality of modules installed include a plurality of pumps 132. Such arrangements are beneficial as if a module 176 containing a pump 132 fails, the unit can continue producing reticulated outputs. Further, in such a situation, it would be possible to retrieve the malfunctioning module 176 from the unit 110 and then return the unit 110 to service, whilst repairs are affected to the malfunctioning module 176.

[00188] In the first embodiment, the propulsion system 146 is configured as two thruster modules 145, each adapted to be releasably mounted in opposed relation on the body 116, arranged at opposed ends thereof along the major axis. Other arrangements are possible.

[00189] One such other arrangement is featured in the fifteenth embodiment of the invention, as shown in Figures 22 and 23.

[00190] The propulsion system 146 comprises an integral propulsion system 178 incorporated in the body 116. The integral propulsion system 178 comprises thrusters 180 incorporated on the body 116 and a drive system 182 operable to drive the thrusters 180. The drive system 182 incorporates a power pack 184 which is removable from the body 116 after installation of the unit 110 at the installation site 108.

[00191] The power pack 204 is shown in Figure 22 still aboard the unit 110. For illustrative purposes, the power pack 204 is also shown separately floating on the surface 04 in Figure 22. As can be seen in Figure 22, the power pack is arranged to be buoyant when in a condition removed from the unit 110 it can float on the water surface 104.

[00192] In the first embodiment tethers 134 are anchored to the sea floor 106 by way of fixtures 166 in the sea floor 106. The fixtures 166 each comprise an anchor 168 embedded in the sea floor 106. Other arrangements are possible.

[00193] Referring now to Figure 24, there is shown a sixteenth embodiment of the invention. This embodiment is similar to the first embodiment, except that the common reticulation line assembly 154 runs to one of the tethers 134 and then descend along the tether to run along the floor of the body of water to a destination.

[00194] Referring now to Figure 25, there is shown a seventeenth embodiment of the invention. This embodiment is similar to the first embodiment, except that, the common reticulation line assembly 154 is arranged to descend along one of the tethers 134 through an axial passage within the tether.

[00195] Referring now to Figure 26, there is shown an eighteenth embodiment of the invention. This embodiment is similar to the first embodiment, except that, the common reticulation line assembly 154 runs as a catenary descending to the sea floor 106 to a destination away from the unit 110.

[00196] Referring now to Figure 27, there is shown a nineteenth embodiment of the invention. This embodiment is similar to the first embodiment, except that, the common reticulation line assembly 154 is arranged with a plurality of buoyancy modules 151 along its length, causing it to descend from the unit 100 in a wave like shape.

[00197] In accordance with twentieth embodiment of the invention, as shown in Figure 28, there is provided a buoyant fixture 186 which is operably connected to an anchor 168 embedded in the sea floor 106. In the arrangement as shown, the buoyant fixture 186 is secured by a chain portion 188 to the anchor 168. The buoyant fixture 220 would typically be installed at the time the anchor 166 was embedded in the sea floor 106.

[00198] The arrangement as shown in Figure 28, being of particular benefit if the installation site 108 is located in deep water, wherein the height the buoyant fixture 186 sits in the body of water 108 can be kept at a uniform depth, therein allowing the tethers 134 of the unit 110 to be of a uniform length regardless of the intended installation location.

[00199] It should be appreciated that the scope of the invention is not limited to the scope of the various embodiments described.

[00200] It should be appreciated that the system as described, while simple and robust, as well as cost-effective, produces a reticulated output (such as electricity or potable water), with such production being accomplished within the wave energy converter for delivery to users; that is, wave energy conversion and the reticulated output are each generated in the one unit operating within the body of water.

[00201] Further, the reticulated outputs when in the form of electricity and potable water are more marketable to end users.

[00202] Moreover, the integration of wave energy conversion and electrical generation into one unit allows the reticulated output(s) to be sent to users not necessarily onshore. More particularly, the reticulated output(s) to be sent to users at offshore locations, including for example offshore oil and gas platforms, moored vessels, or any other stationary offshore entity having an energy and water requirement.

[00203] This is advantageous as it is substantially easier to supply energy to these users as fully conditioned, grid connectable electricity and potable water which they can readily use, as opposed to supplying a source of pressurised fluid which would then have to run through a separate hydraulic power station in order to extract electrical power and/or a separate reverse osmosis desalination unit to yield potable water.

[00204] In the embodiments described, the reticulated outputs are in the form of electricity and potable water. There may be circumstances where there is not a requirement for both electricity and potable water; for example, there may be instances where only electricity is required and other instances where only potable water is required. In such circumstances, the wave energy conversion system according to the invention can be varied as necessary to provide the required reticulated output.

[00205] Further, the wave energy conversion system may be configured to utilise the pressurised fluid in ways other than for generation of electricity and production of potable water. [00206] The various embodiments described and illustrated each have certain features which are not necessarily described and illustrated in other embodiments. However, it should be understood that a feature described and illustrated on any embodiment may be incorporated into any other embodiment where appropriate, whether or not that other embodiment has been described and illustrated herein. In particular, it should be understood that all features described and illustrated in relation to embodiments in which the body 116 is of elongate configuration can be applied equally (as appropriate) to embodiments in which the body 116 is of circular configuration when viewed in plan.

[00207] Modifications and variations such as would be apparent to the skilled addressee are considered to fall within the scope of the present invention.

[00208] Reference to positional descriptions, such as "upper", "lower", "top" and "bottom", are to be taken in context of the embodiment depicted in the figures, and are not to be taken as limiting the invention to the literal interpretation of the term but rather as would be understood by the skilled addressee.

[00209] Additionally, where the terms "system", "device", and "apparatus" are used in the context of the invention, they are to be understood as including reference to any group of functionally related or interacting, interrelated, interdependent or associated components or elements that may be located in proximity to, separate from, integrated with, or discrete from, each other.

[00210] Throughout this specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.