AU2003100899A4 - Method and Apparatus for Removing and Preventing Marine Growth and Organisms - Google Patents

Description

P001 Section 29 Regulation 3.2(2)

AUSTRALIA

Patents Act 1990 INNOVATION SPECIFICATION STANDARD PATENT Application Number: Lodged: Invention Title: Method and Apparatus for Removing and Preventing Marine Growth and Organisms The following statement is a full description of this invention, including the best method of performing it known to us: METHOD AND APPARATUS FOR REMOVING AND PREVENTING MARINE GROWTH AND ORGANISMS FIELD OF THE INVENTION The present invention relates to a method and apparatus for removing and preventing marine growth and organisms on underwater structures.

BACKGROUND OF THE INVENTION One problem with static underwater structures is the growth of marine organisms. This is a significant problem with the hulls of boats in docks or pilings of oil rigs and the like. Manually removing marine growth is a troublesome and costly exercise; furthermore this is simply a reactionary and temporary measure.

A widely used and more preventative measure is the application of special paint to the underwater structure. However, such paints tend to be toxic in composition and, therefore, not environmentally friendly.

As a concept, it is well known that marine organisms will not grow on structures which are located in flowing or moving water. This concept has been used to provide an alternative environmentally friendly solution to the problem of marine growth. Examples of these solutions are known in US Patent Application No. 2003/0001291 and Japanese Patent Application No. 2001-106179. Each of these prior art solutions incorporate an aeration device located underneath or near the structure. The aeration devices include a tubular framework placed on the water bed. The tubular framework includes holes along its surface. A motor pumps air into the tubular framework via a single airline. The air is expelled from the holes as a stream of bubbles. The bubbles agitate the water around the structure, hence removing and preventing the growth of marine organisms.

In practice, it has been found that the prior art solutions only work satisfactorily when the tubular framework is placed on a level water bed. When the framework is placed on an uneven or sloped water bed, part of the framework will be higher than the rest. Air which is pumped into the framework will tend towards the highest part of the framework. As a result, there is an uneven distribution of expelled air which reduces the effectiveness of the device from removing and preventing marine growth from the structure.

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It is an object of the present invention to provide a method and aeration apparatus which overcomes the problems associated with the prior art and provides an even distribution of expelled air.

SUMMARY OF THE INVENTION According to a first aspect of the present invention there is provided an aeration apparatus for removing and preventing the growth of underwater marine organisms on an underwater structure, said apparatus including: a tubular framework, including: at least two air inlets, each air inlet associated with a different section of the framework; and a plurality of air outlets arranged along the surface of the framework; air supply means connected to and providing air pressure to each air inlet, wherein air provided to each air inlet is emitted from the air outlets in the form of air bubbles; anchoring means for retaining the framework on a water bed proximate the underwater structure, thereby enabling the air bubbles to agitate water contiguous to the underwater structure; and means for controlling the air pressure to each air inlet, in a manner whereby the air pressure to each air inlet may be adjusted to compensate for different water pressures at each section of the framework and provide an even distribution of air bubbles from the whole framework.

Preferably, the controlling means is a three-way valve.

Preferably, the apparatus further includes non-return valves to prevent water from flowing to the air supply means when the air pressure falls below the water pressure. This would save the need to disconnect the air supply when the apparatus is not being used.

According to a second aspect of the present invention there is provided a method for removing and preventing the growth of underwater marine organisms on an underwater structure, said method including the following steps: providing a tubular framework, said framework including: at least two air inlets, each air inlet associated with a different section of the framework; and a plurality of air outlets arranged along the surface of the framework; supplying air pressure to each air inlet, wherein air provided to each air inlet is emitted from the air outlets in the form of air bubbles; anchoring the framework on a water bed proximate the underwater structure, thereby enabling the air bubbles to agitate water contiguous to the underwater structure; and controlling the air pressure to each air inlet, in a manner whereby the air pressure to each air inlet may be adjusted to compensate for different water pressures at each section of the framework and provide an even distribution of air bubbles from the whole framework.

The present invention offers a number of advantages. Firstly, it is efficient and easy to use. An apparatus installed on the water bed of a marina, for example, would simply require the skipper of a boat to anchor above the apparatus. The air supply is then simply turned on leaving the apparatus to remove and prevent marine growth on the hull of the boat without any further action by the boat's crew. It is estimated that this would reduce the costs associated with hull maintenance by up to 90%. Secondly, the apparatus is environmentally friendly to the water way. Aside from removing and preventing marine growth on structures, the apparatus actually promotes fish populations in the water way. Lastly, the pressure control allows the apparatus to be installed on water beds having an uneven or sloped surface.

BRIEF DESCRIPTION OF THE DRAWINGS Illustrative embodiments of the present invention will be described with reference to the accompanying drawings, wherein: Fig 1A is a plan view of a framework of a preferred embodiment of the invention; Fig 1B is a plan view of a base of a preferred embodiment of the invention.

Fig 2A is a plan view of a preferred embodiment of the invention; Fig 2B is a side view of the preferred embodiment in Fig 2A; Fig 3 is an end view of a preferred embodiment of the invention; Fig 4 is a side view of the preferred embodiment in Fig 3; and Fig 5 is a side view of an alternative embodiment of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS In Fig. 2A there is provided a plan view of one embodiment of the present invention. Shown therein is an aeration device 3. The aeration device 3 includes a tubular framework 1 and a base 4. The aeration device 3 is placed on the bottom of a lake, river or ocean proximate to an underwater structure.

The framework 1 is shown in isolation in Fig. 1A. The framework 1 has two air inlets 5 for feeding air into each side of the framework 1. Non-return valves 2 are placed in association with each air inlet 5. The non-return valves 2 allow air to be fed into the framework 1 but prevent water flowing back towards the air inlets 5 once the air pressure falls below the water pressure. The framework 1 is made of polyvinyl chloride (PVC), although it will be apparent that other appropriate materials may be used. Tests have found the ideal diameter of the framework to be approximately The framework 1 has holes 12 arranged along its length. Air fed into the framework escapes from the framework 1 via the holes 12, see Fig 2B. The air escaping from the holes 12 forms bubbles which agitates the water proximate the underwater structure. Tests have found the ideal diameter of the holes 12 to be 1 mm, and the ideal spacing between the holes to be approximately 120mm.

The framework 1 is secured to the base 4 by support brackets 9. The base is weighted in order to anchor the aeration device 3 to the water bed. The base 4 is shown in isolation in Fig 1 B. Providing a weighted base 4 has been found to be a preferred method of anchoring the framework 3 to the water bed, however, it will be appreciated that the framework 3 may be anchored to the water bed by other means.

Turning again to Fig 2A, the air inlets 5 are connected by airlines 10 to an air supply 7. The air supply is power by a 3-phase electric motor. Tests have shown that the required output air pressure from the air supply 7 and hence the size of the motor to be dependent upon the depth of the framework 1.

Commonly, the framework 1 will be anchored at maximum depth of 3.5m. At this depth, tests have shown that the required air pressure needs to be approximately 330 psi powered by a 4kW motor. It is envisaged that the framework may operate at a maximum depth of 8m. At 8m depth the required air pressure needs to be approximately 550 psi powered by a 20kW motor.

The air supply 7 includes a pressure release valve 8 for controlling the output air pressure.

The air lines 10 are connected to the air supply 7 via a three-way valve 6.

The three-way valve 6 allows the control of air pressure to each air line 10. This control of air pressure to each air line 10 becomes necessary where the framework 1 is anchored to an uneven or sloped water bed. Where the water bed is uneven or sloped, one side of the framework 1 will be at a greater depth than the other side and, hence, the water pressure will be greater at the side of the framework 1 of greater depth. Tests have shown that, when the air pressure to each air line 10 is uncontrolled, the distribution of air escaping the framework 1 is uneven. The escaping air will tend to concentrate from the part of the framework 1 having the lesser water pressure. To compensate for this uneven water pressure, the three-way valve 6 allows the input air pressure to each air line 10 to be balanced, providing an even distribution of air throughout the framework 1.

Although the use of a three-way valve is considered a preferred manner of controlling the air pressure in each air line 10, it will be appreciated that other means of controlling the air pressure in each air line 10 may be employed. For example, each air line 10 may have its own pressure release valve.

In Figs 3 and 4, there is shown an embodiment of the invention in use with a ship 14, the hull 15 of which is below the waterline 12. In this embodiment, the ship 14 is anchored at a marina. The aeration device 3 is anchored to the water bed 13 directly underneath the hull 15. The air supply 7 is situated on a jetty 17.

Air fed into the framework 1 escapes via the holes 12, and rises towards the hull in the form of bubbles 11. The bubbles agitate the water around the hull thereby moving and preventing the growth of marine organisms.

In Fig 5, there is shown an alternative embodiment of the invention. In this embodiment, the aeration device 3 is anchored around the base of a piling 18 of an oil rig. The air supply is situated on the oil rig platform. Again, the bubbles 11 agitate the water around the piling 18 thereby moving and preventing the growth of marine organisms.

The above has described preferred embodiments of the invention. It will be appreciated by one skilled in the art that the invention may be embodied with various adaptations without departing from the scope of the present invention. In particular, the preferred embodiments described above include only two air inlets arranged respectively on each side of the framework. It will be appreciated that in applications requiring particularly large frameworks or in situations where the water bed is particularly uneven there may be problems of water pressure differentials at various sections of the framework. In such cases it maybe necessary to provide more than two air inlets, each air inlet being arranged at different sections of the framework. It will be appreciated that controlling the air pressure to each air inlet, and hence each section of the framework, would improve the distribution of air bubbles. Furthermore, it will be appreciated that it would be possible to implement automatic control of the pressures to the air inlets. A regulator could be provided with inputs indicative of the water pressure at each section of the framework and control the air pressure to each respective air inlet.

Claims (4)

1. An aeration apparatus for removing and preventing the growth of underwater marine organisms on an underwater structure, said apparatus including: a tubular framework, including: at least two air inlets, each air inlet associated with a different section of the framework; and a plurality of air outlets arranged along the surface of the framework; air supply means connected to and providing air pressure to each air inlet, wherein air provided to each air inlet is emitted from the air outlets in the form of air bubbles; anchoring means for retaining the framework on a water bed proximate the underwater structure, thereby enabling the air bubbles to agitate water contiguous to the underwater structure; and means for controlling the air pressure to each air inlet, in a manner whereby the air pressure to each air inlet may be adjusted to compensate for different water pressures at each section of the framework and provide an even distribution of air bubbles from the whole framework.

2. The aeration apparatus of claim 1, including non-return valves for preventing water flowing to the air supply means when the air pressure falls below the water pressure.

3. The aeration apparatus of claim 1 or 2, wherein the means for controlling the air pressure is a three-way valve.

4. A method for removing and preventing the growth of underwater marine organisms on an underwater structure, said method including the following steps: providing a tubular framework, said framework including: at least two air inlets, each air inlet associated with a different section of the framework; and a plurality of air outlets arranged along the surface of the framework; supplying air pressure to each air inlet, wherein air provided to each air inlet is emitted from the air outlets in the form of air bubbles; anchoring the framework on a water bed proximate the underwater structure, thereby enabling the air bubbles to agitate water contiguous to the underwater structure; and controlling the air pressure to each air inlet, in a manner whereby the air pressure to each air inlet may be adjusted to compensate for different water pressures at each section of the framework and provide an even distribution of air bubbles from the whole framework. An aeration apparatus for removing and preventing the growth of underwater marine organisms on an underwater structure substantially as herein described with reference to any of the accompanying drawings. DATED this 29th day of October 2003 ALAN RAYMOND CLARKE GREGORY FRANCIS MCNAMARA WATERMARK PATENT TRADE MARK ATTORNEYS