WO2009058031A1

WO2009058031A1 - Improvements in and relating to wave generation

Info

Publication number: WO2009058031A1
Application number: PCT/NZ2008/000286
Authority: WO
Inventors: Kerry Peter Black
Original assignee: Kerry Peter Black
Priority date: 2007-10-30
Filing date: 2008-10-30
Publication date: 2009-05-07

Abstract

This invention relates to improvements in and relating to wave generation. In particular, this invention is directed to a means of producing high quality surfing waves for a surfing pool. This is effected via an improved wave generating caisson where the pressure means adapted to periodically apply force against the surface of water contained in the caisson, to displace said water from the caisson chamber, is achieved via hydraulic mechanical plunger means. The invention is used in conjunction with computer technology and software to enable wave profiles to be precisely specified. Channeling means are adapted to redirect water from an end of the swimming pool back to the chamber(s) to reset the chamber(s) for further wave generation and at the same time facilitate preferred breaking of generated waves travelling along the swimming pool.

Description

IMPROVEMENTS IN AND RELATING TO WAVE GENERATION

Technical Field

This invention relates to improvements in and relating to wave generation.

In particular, this invention is directed to provide an improved caisson wave generator for the generation of high quality surfing waves for a surfing pool. Further, the invention is used in conjunction with computer technology and software to enable wave profiles to be precisely specified.

It is envisaged the invention will be applicable for use in recreational and competitive wave and surfing pool facilities. However, the invention may have applications outside this field. For example, the invention may be applied in research facilities for testing movement and stability of objects (designed to float or travel on bodies of water) which would typically be subjected to the affects of wave motion and surf dynamics.

Background Art

Pneumatic caisson wave generators have been described in US Patent Nos. 4,812,077 (Raike), 4,730,355 (Kreinbil), 4,558,474 (Bastenof). They employ an enclosed caisson into which pressured air is forced. The pressure drives the water level in the caisson down and out of a slot at the base of the caisson into the surfing pool. Once leaving the slot, the water mounds up in the pool and then heads off as a wave. Variations on the caisson and methods of pressurizing are described in the patents noted above.

These caissons have the benefit of using resonance to drive the water in and out of the caisson. That is, when the water is forced out, the air pressure is released through a venting valve and so the water from the pool "sloshes" back into the caisson. With correct timing, a new pressure surge is created in the caisson when the water level in the caisson is at its maximum elevation. By using the natural rhythm of the water, the amount of power needed to generate the waves is greatly reduced.

The problem with this technique in pools with high quality surfing waves is that the natural oscillation of the caisson has a period that depends on the size of the caisson, but it is usually around 2-4 seconds.

This time is too short for good surfing waves which have periods of 8-20 seconds. Consequently, the • sloshing motion in the caisson becomes a disadvantage because the caisson sends out waves due to this motion too frequently and it is very difficult to control or limit these waves using pressure alone because the air is compressible. Therefore, totally preventing the resonant sloshing is very difficult to achieve with air pressure.

Further problems with the caisson relate to the lack of control that is achievable with the movement of water inside the caisson. The compressibility of the air and the need for rapid movement of the water in the caisson makes it difficult to control the precise movement of the water being discharged from the caisson. Consequently, the water may come out of the caisson too quickly, or too slowly thereby making the production of a high quality wave profile in the pool impossible to achieve.

A further problem arises with the shape of the caisson discharge channel. In previous inventions, the water coming out of the slot in the base of the caisson is moving around the narrow face of the caisson. This has the adverse affect of causing vortices to form on either side of the face. The vortices reduce the quality of the wave and also the energy that goes into these vortices is wasted as the vortices do not contribute to the surfing wave. As such, the energy requirements for the caisson are higher than what could be achieved if the vortices were eliminated. The importance of this aspect has not been fully recognised by previous inventors.

It is essential to find the means to control the water movement in and out of the caisson more precisely and to overcome the resonant sloshing in and out of the caisson to produce high quality waves for surfing. In addition, the channel in front of the caisson needs to be designed to eliminate vortices. The current invention is directed to addressing these problems.

Another problem relates to the formation of rip currents in the pool. Rips occur when the breaking intensity of the wave across the pool is not even. Sometimes, for good surfing, the wave will be breaking on a reef in the pool that will run diagonally across the pool floor. This causes the waves to break more on one side of the pool than the other. The energy generated by the breaking wave is converted into a current through the process known as radiation stress. This current flows in the direction of the waves in the breakers and returns down the pool in the opposite direction in the zones where the waves are smaller or not breaking. The phenomenon is seen on beaches worldwide and is known as a rip current. The force which drives the rip current is a pressure gradient i.e. a slope on the water surface. The water coming down the pool with the waves, on reaching the far end of the pool, builds up the water level at that end. This phenomenon, known as set-up, then induces a pressure gradient which causes the rip current to accelerate towards the wave generator end of the pool and to become a nuisance in the pool. One solution is to pump the water back to the generator end of the pool. However, the cost of the pumping can be very expensive. Here, a solution is presented that uses the wave generator as the pump, thereby greatly reducing the energy required to return the set-up water to the wave generator end of the pool and thereby reduce or eliminate the rip currents.

Moreover, in order to direct the flow into the pipe and back to the generator, the water flowing away from the generator with the waves must be turned by some 180°. One obvious solution is to use the head created by the buildup of water at the top of the pool to help drive the flow into the pipe. Using head, the water may flow directly into the pipe or via a route consisting of entry grates in the pool floor and linking pipes under the floor of the pool. The problem with this is that the horizontal water currents must change direction from horizontal to vertical in order to travel down through the grates. The loss of energy associated with this transition causes the water to "bank up" and create a head that worsens the rip currents in the pool. In essence, this transition is equivalent to a conversion of the kinetic energy of the water flow into potential energy (or head).

Another problem is associated with the one-way valves in the pipe system. While these valves prevent water flowing in the wrong direction in the pipe due to the action of the wave generator, they also act to stop the water flow in the pipe during each half wave cycle when they are closed. Consequently, the water flow is constantly stopping and starting which reduces the total volume of water that travels down the pipe towards the wave generator.

Another problem with wave pools is that the generator uses electrical energy. One solution is to retrieve as much of this energy as possible. This can be achieved by using the heat coming from the pumps and rams to make electricity by turbine or other means. Alternatively, the heat can be used to warm the water in the pool for surfing comfort.

While the present invention has a number. of potentially realisable applications, it is in relation to problems associated with existing wave generating caissons and the quality and control of surf waves produced that the present invention was developed. More specifically, it was with regard to the issues of providing a system capable of precisely generating waves of preferred profiles. It was also developed with safety issues typically associated with such systems in mind, that the present invention was developed. Finally, it was having regard to the need to provide a system that would be energy efficient.

It would be useful therefore, to have a surf/wave generating system that: L Could be programmed and operated to generate specifically profiled waves; and 2. Considered and improved on safety issues of existing systems; and

3. Was effective at producing such surf waves without the inherent problems of existing systems; and

4. Effected less wastage of energy; and 5. Produced waves at preferred time intervals suited to surfing; and

6. Helped, where applicable, to maximise the potential to use wave generator as a pump to return the set-up water from the far end of the wave/surf pool to the wave generator end of the pool; and

7. Contributed to improving the surfing experience; and 8. Minimised the possibility of vortices in the vicinity of the wave he generator and rip currents in the pool; and

9. Provided a more cost effective alternative to present systems employed, and

10. Provided a consistent high quality surf wave, so that the wave could be reliably generated for competitive surfing, or for research purposes; and 11. Would be easy to operate; and

12. Presented an alternative method that uses both the kinetic energy and the potential energy of the flow without making the troublesome conversion between the two forms to direct the flow into the pipe and back to the generator; and

13. Addressed the problem of one-way valves in the pipe system which operate to stop the water flow in the pipe during each half wave cycle when they are closed.

It would therefore be advantageous to have an invention that offered at least some, if not all, of the potential advantages of the above proposed wave generation system. It is therefore an object of the present invention to consider the above problems and provide at least one solution which addresses a plurality of these problems.

It is another object of the present invention to at least provide the public with a useful choice or alternative system. Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only. It should be appreciated that variations to the described embodiments are possible and would fall within the scope of the present invention.

Disclosure of Invention

Various water sport activities such as surfing (and particularly competitive surfing) require a large wave with a longer period between each wave. Prior art wave generating systems may achieve varying wave sizes and wave periods, but it is preferable to achieve the desired wave profile and generation with greater control and precision than has been achieved to date.

This invention is directed to provide an improved caisson wave generator for the generation of high quality surfing waves for a surfing pool. Further, the invention is used in conjunction with computer technology and software to enable wave profiles and wave periods to be precisely specified.

Typically wave generators are associated with the deep end of a swimming or surf pool. One or more wave generating caissons or a caisson having a plurality of wave generating chambers, would be employed - the actual number being dependent on the size of the pool. The caisson comprises at least one chamber which contains a defined quantity of the pool water and a pressure means for forcing that water from the chamber into the pool.

The caissons typically communicate with the water in the pool through a submerged passage. The caissons are actuated to provide pressure via the pressure means against the enclosed body of water within the caisson chamber. The water level therein is then driven down and out of the caisson and into the pool, thereby creating waves in the pool.

In relation to the present invention, the term "pressure means" shall include the means by which a volume of water in a caisson chamber is forced or displaced from the chamber and into an associated/interconnected pool of water. Whilst it is acknowledged that the prior art describes systems which include pressure means, such pressure means comprise air or are air-activated. The differentiation in relation to the present invention is that the pressure means is mechanical and driven by other than air activation alone. For example, the present invention includes a plunger in the caisson, driven by hydraulic rams. However, this should not be seen to limit the present invention to mechanical hydraulic pressure means, alone. A combination system may be envisaged in which the pressure means is primarily mechanical utilising hydraulic with or without pneumatic operating systems in various combinations as required to achieve the preferred force to displace the required body of water from the caisson chamber and propel that water into the associated pool.

Ih addition, for the purpose of the present invention the term "plunger" shall be used to refer to a mechanical element of the pressure means. However, the term "plunger" shall apply to any device which can be applied in a thrusting or plunging manner. Typically, the configuration of the plunger may be box-like or comprise a substantially fiat plate. In addition the plunger face which contacts the water may be substantially planar. However, this does not preclude/exclude plungers having a concave plunging face, or being otherwise configured. The focus is on a plunger having the required dimensions and shape to maximise the force applied against the surface of the body of water in the caisson chamber for displacing that water from the chamber.

According to one aspect of the present invention, there is provided for use with a swimming pool, a surf wave generator comprising: at least one caisson chamber having an opening allowing the lower portion of the chamber to communicate with the lower portion of the swimming pool; a reservoir of water in said chamber; and pressure means to rapidly induce displacement of the water therein into said swimming pool; said chamber having sufficient volume of water when compressed and delivered to the swimming pool to propagate a traveling wave within said pool, said surf wave generator characterised by the pressure means being an hydraulically operated mechanical plunger.

According to one aspect of the present invention there is provided a device for producing waves in a body of water comprising: a chamber having substantially vertical internal side walls and a base, said chamber being at least partially filled with water, pressure means adapted to periodically apply force against the surface of the contained water to displace said water from the chamber, operating means for moving the pressure means in a preferred direction and with the required force applied against the surface of the water contained in the chamber, said chamber also including an opening through which the water exits the chamber when the pressure means is applied there against, said opening connected to a channel to direct the water from the chamber and towards the body of water, and said water being discharged into the body of water at a preferred point and with sufficient force into the body of water to generate a wave of preferred profile in the body of water. According to another aspect of the present invention there is provided a wave generating system for use in generating waves in a swimming pool comprising: one or more chambers communicative with said swimming pool through a below the water passage and having a pressure means directed to apply pressure to pool water in the chamber to force the chamber water through the below the water passage and into the swimming pool with a force and at an entry point and angle sufficient to create a wave effect in said pool.

According to another aspect of the present invention, there is provided a method of surf wave generation in a swimming pool having a water-filled caisson coupled to the swimming pool beneath the swimming pool water surface, comprising the steps of: displacing the volume of water in the caisson using a plunger that fits within the caisson chamber and is controlled using hydraulic rams to displace a required volume of water from the caisson and into the swimming pool with a velocity and at an entry point and angle sufficient to create a preferred wave effect in said pool.

A method of wave generation substantially as described above wherein means are provided to direct water from the swimming pool back into the caisson to reset the caisson for a further wave generating cycle.

The water is preferably returned to the caisson through either or both, in unison or in series, an opening by which the lower portion of the chamber communicates with the lower portion of the swimming pool and a second connection within the caisson that takes water from the top end of the pool. The return of water from the top end of the pool to cure problems associated with rip currents is one potentially realisable advantage of the present invention.

The present invention is directed to a modified caisson wave generator for high quality surfing waves consisting of a caisson which includes a plunger that moves vertically within the caisson and is controlled by hydraulic rams that move the plunger with high precision using controlling computer or PLC electronics.

According to another aspect of the present invention there is provided programmable control means for initiating and regulating operation of the caisson, said control means being electronic in operation and including: a power source, a device to sense the position of the pressure means including the plunger, a microprocessor able to run software for determining and controlling the operation of the pressure to a pre-determined wave generating regime and wave profile. The wave generating caisson is controlled by the computer and includes a software interface that allows the wave profile to be precisely specified. The power source will preferably be electrical and operate a motor which drives the hydraulic system of the present invention.

Preferably, the electronics that control the movement of the plunger will be linked to a computer that has software programmed with the shapes of the waves to be produced.

The control means not only controls the triggering of the plunger action, but determines the hydraulic force applied, the sequence timing of the wave generation cycles per se, effects operation of return valves directing water back into the caisson chamber once emptied and is able to be reprogrammed to effect recalibration of the process to achieve varying profiles of waves and frequency of waves.

Preferably, the caisson plunger will including motive means, such as wheels or guide means, such as guiding supports to assist the movement of the plunger up and down the wall of the caisson and minimise the potential for j amming thereof.

Preferably, the internal surface of the caisson chamber will include a smooth surface to substantially minimise friction/resistance otherwise likely to be generated between the surface of the plunger touching the chamber wall and the chamber wall itself. This is required to ensure smooth and timely operation of the plunger against the water body in the caisson chamber. Accordingly, the internal surface of the caisson chamber may be possibly made of a polyethylene or similar durable and smooth material.

Preferably, the internal configuration of the caisson will be bowl-shaped - with a rounded internal face joining the back wall to the floor of the generator below the plunger.

Preferably the plunger will be box-like or plate-like. The dimensions of the plunger will be comparable to the surface area and dimensions of the chamber to ensure effective force is applied against the body of water to force the water out of the caisson chamber via the caisson exit passage, without loss of pressure due to seepage of water between the plunger and the caisson walls to fill the void created above the plunger as the plunger depresses the body of water.

Preferably, the plunger motion will have sufficient height to ensure that water is displaced over the full stroke of the plunger movement, without substantial volumes of water resting on top of the plunger or the plunger coming out of the water. Preferably, to generate a 2-3 metre wave in the pool, the surface dimensions and hence surface area of the caisson will be 3 metres by 9 metres and the plunger stroke length will be 3 metres.

Preferably, the plunger will have a preferred density and mass; the preferred weight of the plunger being determined to achieve the goal of equalizing the upward and downward forces on the rams that move the plunger.

Preferably the plunger face contacting the water in the caisson chamber will be substantially planar. In addition, the plunger face is preferably oriented in a substantially horizontal plane. However, in some embodiments the plunger may be set at an angle such that the plunger face is oriented towards the internal front face of the caisson chamber and towards the exit slot. In such embodiments, the floor of the caisson chamber may be complementarily angled.

Preferably, the plunger will have one or more controlling hydraulic rams that are either above or below the plunger and supported by either a strong frame above the caisson or mounted into the floor of the caisson.

Preferably, the lower face of the plunger will not rise above the still water level in the pool when the plunger is raised to its pre-compression position within the caisson chamber at the re-setting of the wave generating cycle.

A specifically designed exit path for the water coming out of the caisson is directed to substantially eliminate or greatly reduce the formation of vortices in and immediately outside the caisson.

Therefore, preferably, the internal front face of the caisson chamber will be sufficiently wide and rounded. The front face of the caisson will also include an exit slot located at the base of the front face and adjacent the bottom of the caisson chamber. The exit slot is in communication with an exit channel^' providing the exit path for the water forced from the caisson chamber to be directed in to the pool.

The exit slot and exit channel taking water from the caisson to the pool, are located below the bottom of the pool.

Preferably, the exit channel will include rounded surfaces to prevent vortices. Preferably, the exit channel will be curved outwardly from the caisson chamber and upwardly towards the bottom of the pool. At the point of entry of the exit channel into the pool the exit opening of the channel is horizontal with the surfing pool floor.

Preferably, the exit channel will discharge the water into the pool at an upward angle between 25° and 80° to the horizontal.

Whilst the configuration of the channel may be adapted to different forms, lengths and so forth, there are effects consequential to such changes of dimensions and shape of the exit channel - such as flattened versus round, narrow versus wide, straight versus curved pipe, and so forth.

If the channel is too narrow, the water exits the channel as a jet which creates disadvantageous vortices. If the channel is too wide, the wave becomes "flattened" and small in height, as the water spreads over a broader region rather than piling up at the generator to make a steep wave.

If the exit is angled so that the water comes out horizontally into the pool the wave does not form. If the water comes out vertically, the wave is too steep and the water surface can effectively "boil", and the energy is lost in turbulence. The vertical jet can also break through the surface of the water like a geyser, rather than creating a mound of water for a wave.

The water entering the pool from the caisson/exit channel will therefore create a surf wave having preferred height and form in accordance with the programmed wave profile.

To maintain continued wave generation over a period of time, water is required to be directed from the pool back into the caisson chamber for the next cycle of compression.

Preferably, water from the far end of the pool will be returned to the wave generator by pipes or other means, such that each time the caisson wave generator plunger moves upwards water is drawn into the caisson from the far end of the pool as well as through the exit channel

Preferably, the return flow system from the far end of the pool will have its outlets inside the wave generator caisson or in the exit channel in the vicinity of the exit slot.

As previously discussed, in order to direct the flow into the pipe and back to the generator, the water flowing away from the generator with the waves must be turned by some 180°. One obvious solution is to use the head created by the buildup of water at the top of the pool to help drive the flow into the pipe. Using head, the water may flow directly into the pipe or via a route consisting of entry grates in the pool floor and linking pipes under the floor of the pool. The problem with this is that the horizontal water currents must change direction from horizontal to vertical in order to travel down through the grates. The loss of energy associated with this transition causes the water to "bank up" and create a head that worsens the rip currents in the pool. In essence, this transition is equivalent to a conversion of the kinetic energy of the water flow into potential energy (or head).

The present invention preferably presents an alternative method that uses both the kinetic energy and the potential energy of the flow without making the troublesome conversion between the two forms.

This involves using novel curved vanes at the rear of the pool that cause the waves to sweep between the vanes and be re-directed into a tunnel that leads to the pipe connected to the wave generator. By continuing to break the wave between the vanes, the wave energy is converted to a current in the required direction. However, it should be appreciated that wave breaking is not an essential element of the invention. The waves can sweep around with the set-up current in the absence of breaking between the vanes.

Therefore, according to another embodiment of the present invention there is provided a wave generating system for use in generating waves in a swimming pool substantially as described above wherein channeling means effect re-direction of water from the swimming pool to the wave generator.

According to another embodiment of the present invention there is provided a wave generating system for use in generating waves in a swimming pool substantially as described above wherein the channeling means redirects waves from the pool via a tunnel to a return pipe carrying water from the swimming pool to the wave generator.

The combination of kinetic and potential energy is then usefully employed to assist the wave generator's action of pumping water back to the generator end of the pool. The vanes also act as wave dampening devices that help to eliminate troublesome wave reflections coming from the damping area back into the pool and disturbing the following waves. Thereby, the curved vanes have the potential of greatly improving the quality of the surfing ride in the pool by reducing the rip currents and unwanted wave reflections.

Another problem as previously discussed is associated with the one-way valves in the pipe system. While these valves prevent water flowing in the wrong direction in the pipe due to the action of the wave generator, they also act to stop the water flow in the pipe during each half wave cycle when they are closed. Consequently, the water flow is constantly stopping and starting which reduces the total volume of water that travels down the pipe towards the wave generator.

A preferred proposed solution is achievable whereby one or more outlets are placed along the pipeline route. These branch outlets pass into the pool via the side wall or bottom of the pool along the pipeline route. When the one-way valve between the pipe and the generator is closed, the water can now divert into these branch outlets and into the pool rather than having the flow stopping in the pipe.

According to another embodiment of the present invention there is provided a wave generating system for use in generating waves in a swimming pool substantially as described above wherein the return pipe carrying water from the swimming pool to the wave generator includes at least one outlet located there along.

According to another embodiment of the present invention there is provided a wave generating system for use in generating waves in a swimming pool substantially as described above wherein the outlet diverts water from the return pipe and into the pool.

Alternatively, when the wave generator is drawing water, the return water can flow along the pipe to the generator, rather than only via the branches .

Using the branch system, the return flow in the pipe is greatly enhanced when multiple waves are generated and so the invention acts to reduce water levels that are causing the rip currents. Thereby, the branches have the potential to greatly improve the quality of the surfing ride in the pool by reducing the rip currents.

Preferably, the deflector vanes will be placed beyond the surfing zone in the pool to reduce unwanted wave reflections and water level set-up that causes rip currents.

Preferably, the deflector vanes will direct the water into a return flow pipe that runs along the side of the pool and links to the wave generators or into the pool near the wave generators

Preferably, the multiple adjacent deflector vanes will be designed to have converging channels between them that keep the waves breaking and accentuate the flow magnitude. Preferably, the deflector vanes will be placed at an angle to the waves in a way that minimizes troublesome wave reflections back into the pool.

Preferably, the deflector vanes will act to help damp out the waves

Preferably, the return flow pipeline will have branches that lead from the pipe into the pool along the side wall or through the bottom of the pool.

Preferably, the pipe system will have one or more one-way valves that prevent water returning to the far end of the pool when the generator plunger moves downward to expel the water from the caisson during the next wave generation cycle.

Preferably, a means will be provided to reduce or prevent the flow of water into the caisson via the exit channel when the generator plunger is moving upwards. This system will encourage water coming into the caisson to come from the far end of the pool. This is designed to quickly replace the volume of water stored in the caisson and the rate at which successive waves can then be generated.

Preferably, the means could be one or more one-way valves that are fitted across the outlet of the exit channel. A number of one-way valves are available in the prior art. Any suitable valve may be manufactured for or therefore adapted for use with the present invention.

Preferably, the valves are made of flaps of rubber or other suitable material.

Preferably, the flaps open and close in response to the water flow driven by the generator and/or controlled by the computer operating means .

With any hydraulic ram-operated system heat is produced. Preferably, the heat generated by the wave generator oil pumping hydraulic system will be captured and used to generate electricity for powering the site, be re-used to power the wave generator, or for heating the pool water, thereby make the system more energy efficient.

Preferably, the heat generated by the wave generator oil pumping system will be captured and used to generate electricity for powering the site, re-used to power the wave generator, or for heating the pool water, thereby make the system more energy efficient. It will be appreciated that the invention broadly consists in the parts, elements and features described in this specification, and is deemed to include any equivalents known in the art which, if substituted for the prescribed integers, would not materially alter the substance of the invention.

Variations to the invention may be desirable depending on the applications with which it is to be used. Regard would of course be had to effecting the desired wave cycle, wave profile and so forth as required to effect the desired outcome within the surf wave pool - such as recreational, competitive or research driven.

The present invention is differentiated from existing systems by virtue of the specific ability to determine and apply preferred wave profile, in using an hydraulic operated wave generation caisson, designing an exit channel which minimises creation of vortices and including a return water system which addresses problems of rip currents in the wave pool, all of which combine to provide an energy efficient wave generating system the operation of which can be regulated and adapted as required, and so forth.

Whilst some varying embodiments of the present invention have been described above and are to be yet exampled, it should further be appreciated different embodiments, uses, and applications of the present invention also exist. Further embodiments of the present invention will now be given by way of example only, to help better describe and define the present invention. However, describing the specified embodiments should not be seen as limiting the scope of this invention.

Brief Description of Drawings

Further aspects of the present invention will become apparent from the following description, given by way of example only and with reference to the accompanying drawings in which: •^{• ■} .

Figure 1 is a cross-sectional representation of a wave generating caisson with plunger and exit channel in front of the generator in accordance with one embodiment of the present invention; and

is a cross-sectional representation of a wave generating caisson with plunger and exit channel in front of the generator in accordance with another embodiment of the present invention; and Figure 3 is a schematic diagram illustrating fhe interconnection between the caisson, the electronic/computer operating system, the hydraulic operating system in accordance with one embodiment of the present invention; and

Figure 4 is a plan representation illustrating return of water from the end of the wave pool back to the caisson in accordance with one embodiment of the present invention; and

Figure 5 is a top plan representation illustrating water circulation from the end of the wave pool back to the caisson and the piping used to equalize water pressure in the pool, in accordance with one embodiment of the present invention; and

Figure 6 is a side view illustrating the dampening vanes in accordance with one embodiment of the present invention.

Best Modes for Carrying Out the Invention

With reference to the present invention there is provided an improved wave generating system (illustrated in one embodiment in Figure 1).

The wave generating system includes a wave generating caisson (generally indicated by arrow 1) in fluid communication with a swimming or wave/surf pool (2). The caisson will be located adjacent the pool in an appropriate location.

The caisson comprises at least one chamber (3) which contains a defined quantity of the pool water (4) and pressure means including a plunger (5) for forcing that water from the chamber into the pool. The caisson chamber includes internal walls (3a) and a floor (3b). The internal configuration of the caisson chamber of Figure 1 is substantially bowl-shaped - being substantially rounded with vertical internal walls and a rounded concave floor.

The caisson (1) communicates with the water in the pool (2) through a submerged passage (6).

The caissons are actuated via mechanical means (hydraulics) powered by operating means (electricity) to provide pressure/force via the pressure means/plunger to displace (5) against the enclosed body of water (4) within the caisson chamber (3). The water level therein is then driven down and out of the caisson and into the pool, thereby creating waves in the pool. The present invention, directed to a caisson wave generator for generating high quality surfing waves, includes pressure means in the form of a mechanical plunger (5) that moves vertically within the caisson and is controlled by hydraulic rams (7) that move the plunger with high precision using controlling computer or PLC electronics (8). A software interface allows the preferred wave profile to be precisely specified.

The caisson plunger will include motive means, (9) such as wheels (9a) or guide means (10), such as guiding supports (10a) to assist the movement of the plunger (5) up and down the interior walls (3a) of the caisson and minimise the potential for jamming thereof.

The plunger illustrated in Figures 1 through 4 is box-like or plate-like, with dimensions and shape comparable to the surface area and dimensions of the chamber to ensure effective pressure is applied against the body of water to force the water out of the caisson chamber. The plunger-face (5a) contacting the water in the caisson chamber is substantially planar and is oriented in a substantially horizontal plane. The lower face of the plunger will not rise above the still water level in the pool when the plunger is raised to its pre-compressϊon position within the caisson chamber at the re-setting of the wave generating cycle.

In one embodiment, the surface dimensions and hence surface area of the caisson will be 3 metres by 9 metres and the plunger stroke length will be 3 metres. This is the required dimensions to generate a 2-

3 metre wave in the wave pool. However, other dimensions and configurations may be used as required for differently sized wave pools, depending on the number of chambers percaisson, and so forth. For example the caisson may have multiple chambers, have those chambers interlinked to enable displaced water to enter the pool at the same time, at different times, in combination/unison or in series and so forth as required.

The plunger movement and direction of movement is controlled by the operation of hydraulic rams (7) above or below the plunger and supported by either a strong frame above the caisson or mounted into the floor of the caisson. The hydraulic rams are actuated in a conventional manner to move the plunger between a retracted and an extended position relative to the beginning or end of the wave generation cycle and depending on the location of the hydraulic rams relative to the plunger. Any number of hydraulic rams may be used with the invention. The potential also exists for hydraulic and pneumatic rams to co-operate and so forth. The present invention also includes a specifically designed exit path (generally indicated by arrow 10) for the water coming out of the caisson. The design is directed to substantially eliminate or greatly reduce the formation of vortices in and immediately outside the caisson.

The exit path commences in the caisson chamber where an exit slot (11) is located at the base of the front face and adjacent the bottom of the caisson chamber. The exit slot is in communication with an exit channel (12) providing the exit path for the water forced from the caisson chamber to be directed in to the pool. The exit slot and exit channel taking water from the caisson to the pool, are located below the bottom of the pool.

In the embodiment illustrated in Figure 1 the exit channel includes substantially rounded surfaces to substantially reduce o prevent vortices 7- and is curved outwardly from the caisson chamber and upwardly towards the bottom of the pool. At the point of entry of the exit channel into the pool the exit opening of the channel is horizontal with the surf pool floor.

The exit channel is adapted to discharge water from the caisson chamber and into the pool at an upward angle between 25° and 80° to the horizontal. The water entering the pool from the caisson/exit channel will therefore create a surf wave having preferred height and form in accordance with the programmed wave profile.

To maintain continued wave generation over a period of time, water is required to be directed from the pool back into the caisson chamber for the next cycle of compression. Water from the far end of the pool (13) will be returned to the wave generator by pipes (14) or other means, such that each time the caisson wave generator plunger moves upwards water is drawn into the caisson from the far end of the pool. The return flow system from the far end of the pool will have its outlets inside the wave generator caisson (15) or in the exit channel (at 15) in the vicinity of the exit slot.

The pipe system will have one or more one-way valves (16) that prevent water returning to the far end of the pool when the generator plunger moves downward to expel the water from the caisson during the next wave generation cycle. Similar one-way valve systems may be fitted across the outlet (17) of the exit channel to reduce or prevent the flow of water into the caisson via the exit channel when the generator plunger is moving upwards. This system will encourage water coming into the caisson to come from the far end of the pool. The flaps open and close in response to the water flow driven by the generator and/or are controlled by the computer operating means. Operation of the hydraulic rams (directing movement of the plunger) may also be integrally linked to such valves thereby co- ordinating entry of water from the pool back into the caisson chamber prior to commencement of a successive wave generating cycle.

The pipe system includes curved vanes (18) these are located at the rear (at 19) of the pool. The returning waves sweep between the vanes and are re-directed into a tunnel that leads to the pipe connected to the wave generator. By continuing to break the wave between the vanes, the wave energy is converted to a current in the required direction. The waves can however sweep around with the set-up current in the absence of breaking between the vanes.

The vanes also act as wave dampening devices that help to eliminate troublesome wave reflections coming from the damping area back into the pool and disturbing the following waves. Thereby, the curved vanes have the potential of greatly improving the quality of the surfing ride in the pool by reducing the rip currents and unwanted wave reflections.

However, the flow control flaps/valves in the pipes act to stop the water flow in the pipe during each half wave cycle when they are closed. Consequently, the water flow is constantly stopping and starting which reduces the total volume of water that travels down the pipe towards the wave generator. Therefore, one or more outlets (20) are placed along the pipeline route. These branch outlets pass into the pool via the side wall or bottom of the pool along the pipeline route. When the one-way valve between the pipe and the generator is closed, the water can now divert into these branch outlets and into the pool rather than having the flow stopping in the pipe.

When referring to the description of the present invention, it should also be understood that the term "comprise" where used herein is not to be considered to be used in a limiting sense. Accordingly, 'comprise' does not represent nor define an exclusive set of items, but includes the possibility of other components and items being added to the list.

This specification is also based on the understanding of the inventor regarding the prior art. The prior art description should not be regarded as being an authoritative disclosure of the true state of the prior art but rather as referring to considerations in and brought to the mind and attention of the inventor when developing this invention.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof, as defined in the appended claims.

Claims

THE CLAIMS DEFINING THE INVENTION ARE:

1. A device for producing waves in a body of water said device comprising: a chamber having substantially vertical internal side walls and a base, said chamber being at least

, partially filled with water, pressure means adapted to periodically apply force against the surface of the contained water to displace said water from the chamber, said pressure means including mechanical plunger means, operating means for moving the pressure means in a preferred direction and with the required force applied against the surface of the water contained in the chamber, said chamber also including an opening through which the water exits the chamber when the pressure means is applied there against, said opening connected to a channel to direct the water from the chamber and towards the body of water, and said water being discharged into the body of water at a preferred point and with sufficient force into the body of water to generate a wave of preferred profile in the body of water.

2. A device for producing waves in a body of water as claimed in Claim 1 wherein said operating means for moving the pressure means includes hydraulic means.

3. A device for producing waves in a body of water as claimed in Claim 2 wherein said operating means for moving the pressure means also includes at least one of controlling computer, PLC electronics.

4. A device for producing waves in a body of water as claimed in Claim 3 wherein movement of the pressure means is assisted by: a) motive means, and/or b) guide means.

5. A device for producing waves in a body of water as claimed in Claim 1 wherein the body of water is contained within a swimming pool.

6. A device for producing waves in a body of water as claimed in Claim 1 wherein the waves of preferred profile produced are waves suitable for surfing.

7. A surf wave generator for use -with a swimming pool, said surf wave generator comprising: at least one chamber having an opening allowing a lower portion of the chamber to communicate with a lower portion of the swimming pool; a reservoir of water in said chamber; and moveable pressure means to rapidly induce displacement of the water therein into said swimming pool; said chamber having sufficient volume of water when compressed and delivered to the swimming pool to propagate a traveling wave within said pool, said surf wave generator characterised by the pressure means including hydraulic operated mechanical plunger means.

8. A wave generating system for use in generating surf waves in a swimming pool, said wave generating system comprising: one or more chambers communicative with said swimming pool through a below the water passage and having a pressure means directed to apply pressure to pool water in the chamber to force the chamber water through the below the water passage and into the swimming pool with a force and at an entry point and angle sufficient to create a traveling wave effect in said pool; and said wave generating system characterised by the pressure means being an hydraulically operated mechanical plunger means.

9. A wave generating system for use in generating surf waves in a swimming pool as claimed in Claim 8 wherein said wave generating system includes channeling means to redirect water from an end of the swimming pool back to the chamber(s) to reset the chamber(s) for further wave generation.

10. A wave generating system for use in generating surf waves in a swimming pool as claimed in Claim 9 wherein the channeling means includes at least one entry.

11. A wave generating system for use in generating surf waves in a swimming pool as claimed in Claim 10 wherein the at least one entry includes deflector means.

12. A wave generating system for use in generating surf waves in a swimming pool as claimed in Claim 11 wherein the deflector means are angled into the swimming pool.

13. A wave generating system for use in generating surf waves in a swimming pool as claimed in Claim 12 wherein the angled deflector means are further adapted to facilitate preferred breaking of generated waves travelling along the swimming pool.

14. A method of surf wave generation in a swimming pool having a water-filled chamber coupled to a swimming pool beneath the swimming pool water surface, said method comprising the steps of: displacing the volume of water in the chamber using pressure means, said pressure means including a mechanical plunger means, said plunger means controlled using hydraulic means to displace a required volume of water from the chamber and into the swimming pool with a velocity and at an entry point and angle sufficient to create a preferred wave effect in said pool.

15. A method of wave generation as claimed in Claim 14 wherein means are provided to direct water from the swimming pool back into the chamber to reset the chamber for a further wave generating cycle. •

16. A method of wave generation as claimed in Claim 15 wherein water from the swimming pool is returned to the chamber via at least one of: a) an opening by which a lower portion of the chamber communicates with a lower portion of the swimming pool; and/or b) a secondary opening directing water from an end of the swimming pool to the chamber by channeling means.

17. Operating means for use with a device for producing waves in a body of water, said device comprising: a chamber having substantially vertical internal side walls and a base, said chamber being at least partially filled with water, pressure means adapted to- periodically apply force against the surface of the contained water to displace said water from the chamber, said pressure means including mechanical plunger means, operating means for moving the pressure means in a preferred direction and with the required force applied against the surface of the water contained in the chamber, said chamber also including an opening through which the water exits the chamber when the pressure means is applied there against, said opening connected to a channel to direct the water from the chamber and towards the body of water, and said water being discharged into the body of water at a preferred point and with sufficient force into the body of water to generate a wave of preferred profile in the body of water; said operating means being programmable and electronic in operation and including: a power source, a device to sense the position of pressure means wherein the pressure means is an hydraulically operated mechanical plunger, and a microprocessor able to run software for determining and controlling the operation of the pressure means to effect a pre-determined wave generating regime and preferred wave profile.

18. Operating means as claimed in Claim 17 wherein the operating means controls activation of the mechanical plunger, determines the hydraulic force applied, effects the sequence Jiming of the wave generation cycles per se, effects operation of water directed back into the chamber once emptied via control of return valves and is reprogrammable to effect recalϊbration of the process to vary preferred wave profiles and wave generating regimes including frequency of waves.

19. Operating means as claimed in Claim 18 wherein operation of the hydraulic means effects heat generation harnessed to generate energy to provide a power source for at least one of powering the device, heating the pool water, diverting pool water back to the device.