AU2017100987A4

AU2017100987A4 - Cleaning apparatus

Info

Publication number: AU2017100987A4
Application number: AU2017100987A
Authority: AU
Inventors: Andrew John Fairhall
Original assignee: FAIRHALL HOLDINGS 2005 Ltd
Current assignee: FAIRHALL HOLDINGS (2005) Ltd
Priority date: 2012-08-14
Filing date: 2017-07-20
Publication date: 2017-08-17
Anticipated expiration: 2021-08-02
Also published as: CA2823648A1; CL2013002312A1; CA2823648C; AU2013211536A1

Abstract

Cleaning apparatus for cleaning under water netting comprising a floating platform, a winch mechanism, a drive mechanism, a control device, a high 5 pressure water pump, and a cleaning head, wherein the control device is arranged to automatically control the drive mechanism to cause the floating platform to move laterally across the netting, and further arranged to automatically control the winch mechanism to adjust the relative height of the cleaning head with respect to the floating platform, the high pressure water pump 10 arranged to pump water at high pressure out of the cleaning head. Figure 1

Description

1 2017100987 20 Μ 2017

CLEANING APPARATUS FIELD OF THE INVENTION 5 The present invention relates to cleaning apparatus. In particular, the present invention relates to cleaning apparatus for cleaning underwater netting.

BACKGROUND 10 Within the aquaculture industry, various methods have been employed in order to maintain the cleanliness of grower nets used for keeping fish within an enclosed environment for the purposes of breeding these fish. These grower nets or meshes require constant cleaning due to bio fouling, for example from algae that grows on the netting. 15

One method is to send divers down into the enclosure to clean the nets manually. However, this results in increased labour costs.

Another method previously employed is to dip the grower nets in copper 20 antifouling material. However, for cost and environmental reasons this is not always considered favourable.

Various submergible devices have also been developed in order to remove the bio fouling from the netting. 25

For example, US patent application US20100006036 describes a floating device to clean nets. This device includes filtering and disinfection systems in order to maintain the cleanliness of the water in which the fish are bred. 30 As another example, European patent application EP2251102 describes a robotic mechanism that cleans the nets underwater. The robot body moves along the surface of the net and is driven by a propeller. A high pressure water jet is directed towards the net in order to remove the bio fouling. These types of devices are generally manually controlled by a user operating a remote control. 35 Further, these types of devices are generally only allowed to travel in a single direction. 2 2017100987 20 Μ 2017

In yet a further example, PCT application WO2010040171 describes a submarine in situ net cleaner. The device is effectively a submersible mobile vacuum cleaner which is arranged to drive across the netting by use of a propeller. The device 5 includes a camera in order to allow the user to manually control the operation of the cleaner.

Further, alternative known systems typically incorporate an "off-the-shelf" water blaster which either sits on a boat outside of the perimeter of the netting or on a 10 walkway also outside of the perimeter of the netting. Because the water blaster is located outside of the net perimeter, a particularly long hose is required to connect the blaster to the cleaning head as the cleaning head moves around the net. Therefore, there is a significant loss of pressure as a result of the distance between the cleaning head and the water blaster. This therefore reduces the 15 efficiency of the system. Further, these known systems also require a dedicated operator to control the various components of the system.

An object of the present invention is to provide a cleaning apparatus for cleaning underwater netting wherein the cleaning time required to clean a portion of net is 20 reduced. A further object of the present invention is to provide a cleaning apparatus for cleaning underwater netting wherein a dedicated operator is not required. 25 A further object of the present invention is to provide a cleaning apparatus for cleaning underwater netting wherein the apparatus is portable. A further object of the present invention is to provide a cleaning apparatus for cleaning underwater netting wherein there is a reduction in energy loss between 30 a high pressure water pump and cleaner head.

Each object is to be read disjunctively with the object of at least providing the public with a useful choice. 35 The present invention aims to overcome, or at least alleviate, some or all of the afore-mentioned problems. 3 2017100987 20 Μ 2017

Further objects and advantages of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing the preferred embodiment of the invention without 5 placing limitations thereon.

The background discussion (including any potential prior art) is not to be taken as an admission of the common general knowledge.

10 SUMMARY OF THE INVENTION

It is acknowledged that the terms "comprise", "comprises" and "comprising" may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, 15 these terms are intended to have an inclusive meaning - i.e. they will be taken to mean an inclusion of the listed components that the use directly references, but optionally also the inclusion of other non-specified components or elements.

According to one aspect, the present invention provides a cleaning apparatus for 20 cleaning under water netting comprising a floating platform, a winch mechanism, a drive mechanism, a control device, a high pressure water pump, and a cleaning head, wherein the control device is arranged to automatically control the drive mechanism to cause the floating platform to move laterally across the netting, and further arranged to automatically control the winch mechanism to adjust the 25 relative height of the cleaning head with respect to the floating platform, the high pressure water pump arranged to pump water at high pressure out of the cleaning head.

According to a further aspect, the present invention provides a cleaning 30 apparatus for cleaning under water netting comprising a floating platform, a winch mechanism, a drive mechanism, a control device, a high pressure water pump, a high pressure air pump, and a cleaning head, wherein the control device is arranged to automatically control the drive mechanism to cause the floating platform to move laterally across the netting, and further arranged to 35 automatically control the winch mechanism to adjust the relative height of the cleaning head with respect to the floating platform, the high pressure water pump 4 2017100987 20 Μ 2017 arranged to pump water at high pressure out of the cleaning head, the high pressure air pump arranged to pump air at high pressure out of the cleaning head proximate to the high pressure water exiting the cleaning head in such a manner that an air pocket is created around and enveloping the high pressure water. 5

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 10

Figure 1 shows a front perspective view of a cleaning apparatus according to an embodiment of the present invention;

Figure 2 shows a detailed front perspective view of a the floating platform portion 15 of the cleaning apparatus shown in figure 1;

Figure 3 shows a rear perspective view of a floating platform shown in figures 1 and 2; 20 Figures 4 and 5 show a side view and top view respectively of a drive wheel of the floating platform shown in figures 1 to 3;

Figures 6 and 7 show a side view and top view respectively of a cleaning head according to an embodiment of the present invention; 25

Figures 8A and 8B show a side view and top view respectively of a first preferred embodiment of a cleaning head section;

Figures 8C, 8D, 8E, and 8Fshow a top, bottom, side and perspective view 30 respectively of a second preferred embodiment of cleaning head section;

Figure 9 shows a side view of a rotary seal according to an embodiment of the present invention; and 35 Figures 10A and 10B show conceptual views of the operation of the cleaning system according to an embodiment of the present invention. 5 2017100987 20 Μ 2017

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 shows a front perspective view of a cleaning apparatus 101 for cleaning underwater netting according to this embodiment. 5

The cleaning apparatus 101 includes a floating platform 103 which is designed to float upon water. According to this embodiment, the platform is made of aluminium. It will be understood that any other suitable lightweight floatable material may be used. 10

Within the body of the floating platform 103 is a compartment 105 which locates a diesel engine, hydraulic oil pump, a high pressure water pump such as a belt driven pump of the type used in water blasters, driven from the diesel engine, oil and fuel tanks, as well as various control equipment as will be explained in more 15 detail below. The control equipment is provided 12 V DC power via the diesel engine's alternator and battery. The compartment 105 is accessible via two hinged doors. An air compressor may also be provided in the compartment 105. A high-pressure water hose 109 forms part of the high pressure water pump 20 system, in combination with the water pump. The water hose 109 is connected between the water pump and a cleaning head 111.

According to this embodiment, the water pump hose has a length of approximately 25 metres. However, it will be understood that as an alternative, 25 the water pump hose may have different lengths. For example, the hose may have a length not exceeding 40 metres. As a further example, the water pump hose may have a length not exceeding 25 metres. As a further example, the water pump hose may have a length not exceeding 20 metres. 30 In the second preferred embodiment, a separate umbilical air hose 118 is also connected between the air compressor and the cleaning head 111, the air compressor and the air hose forming at least part of a high pressure air system. The length of the air hose is the same as or very similar to that described above for the water hose 109. 35 6 2017100987 20 Μ 2017

Located on the floating platform 103 is a winch mechanism 113 that includes a rotatable reel which is controlled by the control equipment. The winch mechanism is hydraulically driven. A cable 115 is attached at one end to the reel and at the other end to the cleaning head 111. 5

Also located on the floating platform 103 is a drive mechanism including two drive wheels 117 which are arranged to rotate around an axis lying parallel to the netting. A preferred embodiment of drive wheel is described below. The drive mechanism is hydraulically driven and also controlled by the control equipment. 10

Figure 2 shows a more detailed front perspective view of the preferred embodiment of the floating platform portion of the cleaning apparatus.

Figure 3 shows a rear perspective view of the floating platform portion of the 15 cleaning apparatus. Located in a lower portion of the floating platform is a propeller 301. This lower portion of the floating platform is arranged to be underwater when the cleaning apparatus is placed within the cleaning environment. The propeller 301 is hydraulically driven and controlled by the control equipment. The propeller is used to provide thrust to the cleaning 20 apparatus so that the front side of the cleaning apparatus is pushed up against the netting during cleaning. That is, the front side of the cleaning apparatus is the side upon which the drive wheels and winch mechanism are located.

Figures 4 and 5 show a side view and top view respectively of the first preferred 25 embodiment of drive wheel 117. The drive wheel 117 includes a bracket 601 which attaches to the floating platform 103. A hydraulic motor 603 is connected to the hydraulic pump. The hydraulic motor 603 causes the toothed rotor 605 to rotate. As shown in figure 5, the drive wheel includes a number of pivoting fingers 609 which sequentially index onto the net and then unlatch at a defined point as 30 the drive wheel 117 rotates, causing the cleaning apparatus to move laterally across the net as the drive wheels rotate. This allows a positive engagement with the net, but allows the fingers 609 to release from the net before the net winds up onto the wheel. The fingers 609 comprise or include a net engaging portion 610 and a base portion 611. The base portion 611 of each finger is 35 pivotally connected to the wheel 117 at or close to the circumferential perimeter of the main body 607in such a manner that the fingers 609 can rotate or pivot in 7 2017100987 20 Μ 2017 the same plane as the wheel in use, with the net engaging portion 610 extending outwards away from the main body. In the preferred form of the second embodiment of drive wheel 117, rotation or pivoting of the fingers 609 is achieved by forming the main body 607 from two flat circular plates and sandwiching the 5 base portions 611 between them. A pin 613 or similar passes through each of the base portions 611 and each of the two flat plates either side that form the main body. A single plate could also be used, with the fingers attached on one side. 10 Figures 6 and 7 show a side view and top view respectively of the cleaning head 111. According to this embodiment, the cleaning head includes four cleaning head sections or cleaning head discs 701. It will be understood however that there may be one or more cleaning head sections. It should also be noted that the second preferred form of cleaning head disc 850 could be used in place of at 15 least one, some or all of the cleaning head discs 701. A common water inlet pipe 703 connects to water inlet ports 705 to provide water to each of the cleaning head discs 701. The common water inlet pipe 703 includes a water inlet port 707 which connects to the water hose 109 coming from 20 the water pump.

The water inlet ports 705 for each of the cleaning head discs 701 are attached to a rotary seal 709. The rotary seal provides a seal which enables water to be passed to the rotating cleaning head discs 701 while enabling the cleaning head 25 discs to rotate.

In the embodiment which also has an air compressor, a common air inlet pipe (not shown) is connected to the umbilical air hose 118 to provide air to each of the cleaning head sections or discs 701 in a similar manner to that described 30 above for the common water inlet pipes. The common air inlet pipe includes an air inlet port (not shown) which connects to the air hose 118 coming from the air compressor.

The air inlet ports for each of the cleaning head sections or discs 701 are 35 attached to an air rotary seal, similar to, but separate from, that used for the water inlets. The air rotary seal provides a seal which enables air to be passed to 8 2017100987 20 Μ 2017 the rotating cleaning head discs 701 while enabling the cleaning head discs to rotate. The air enters the centre hub of the cleaning head disc 701 via the air rotary seal. 5 The cleaning head 111 also includes jets that force the cleaning head against the net. These jets are directed so as to force the cleaning head against the net and may simply be jets at the rear of each water inlet port 705. These jets may be fed from the main pressurised water line 115 and/or the air line 118. 10 Figures 8A and 8B show a side view and top view respectively of a first preferred form of cleaning head disc 701. At a central point on the cleaning head disc is located a water inlet port 801. In the second preferred embodiment of cleaning head disc 850 as shown in Figures 8c - 8f, an air inlet port is also included. According to both the first and second preferred embodiments, three high-15 pressure water galleries 803 are provided within the body of the cleaning head disc 701 or 850, where each of the three galleries emanates from the centre or hub of the cleaning head disc towards the outer rim of the cleaning head disc. Each gallery is spaced apart from its adjacent galleries by 120°. It will be understood, that as an alternative, different configurations of the water galleries 20 are envisaged. For example, there may be less than or more than three water galleries. Further, the angular spacing between the galleries may vary and is not required to be uniform.

According to this embodiment a stainless steel wear resistant surface is applied 25 to the front face of the cleaning head discs.

At the periphery of the cleaning head disc, the distal ends of the galleries are connected to water jets 805, as shown in Figure 8A. According to this embodiment, the jets are replaceable. However, it will be understood that the jets 30 may be integrated within the cleaning head disc so that they cannot be replaced.

The jets are configured so that high-pressure water exits the cleaning head disc at an angle of 45° with reference to the flat front surface of the cleaning head disc. Due to the thrust caused by the angle of the water exiting from the cleaning 35 head disc, the cleaning head discs are caused to rotate. 9 2017100987 20 Μ 2017

In a similar manner, in the alternative embodiment of cleaning head disc 850 as shown in Figures 8c - 8f, air enters the centre hub of the cleaning head disc 850 via the air rotary seal, and travels from the hub to the circumferential perimeter via cavities or separate dedicated air galleries 851 within the disc, which surround 5 or are proximate to the high pressure water galleries. The air is liberated at the same position, or close to, the water jet nozzles 852. This creates a small pocket of air around the water jet, the air enveloping the water jet. This allows the high pressure water to exit the jet at a higher velocity force as it is not slowed down by the surrounding ambient (i.e. non-water jet) water. This results in greater impact 10 energy by the high pressure water jet on the dirty net, which assists with cleaning. A further advantage is that the surrounding water/air barrier thus created includes cavitation bubbles or voids, which are formed and implode immediately adjacent to the net, assisting the cleaning process. 15 A yet still further advantage of the air/water mix is that the cleaning head 111 remains in better contact with the net. This is due to the difference in overall water density between the front face of the cleaning head 111 and the rear face (furthest away from the net). The aerated water at the front is less dense than that at the rear, which causes the cleaner head to move towards the area of 20 lower density or lower pressure.

Figure 9 shows a side view of a rotary seal 709 that connects the cleaning head disc 701 to the common water inlet pipe 703. The rotary seal 709 includes a mounting flange 901 that locates within a corresponding aperture 807 within the 25 cleaning head disc 701. The rotary seal 709 includes a water inlet port 903 and a water outlet port 905. The water inlet port 903 is connected to the common water inlet pipe 703. The water outlet port 905 is connected to the cleaning head disc 701. 30 The following describes how the cleaning apparatus is operated. The cleaning apparatus is first lifted into the water in the area bounded by the net by a suitable crane. In the preferred embodiment as shown in Figure 1, the cleaning apparatus weighs approximately 700 kg and so a suitable crane is required for lifting this weight 35 10 2017100987 20 Μ 2017

It should be noted that several different and separate items have been described above for the first and second preferred embodiments. These can be mixed and matched between the first and second preferred embodiment as required and the description above should not be taken as an indication that each item described 5 for a particular embodiment must, or must not, be present only for that embodiment.

Figure 10A shows a conceptual view of the operation of the cleaning system. The view of the system is a bird's eye view looking down on the water in which the 10 apparatus is placed. A control module 1001 controls the drive mechanism 1003 which in turn causes the drive wheels 117 to rotate in a clockwise direction as indicated by the arrow. The fish netting 1005 within the water is positioned along a y-axis. The propeller on the cleaning apparatus causes the cleaning apparatus to push up against the fish netting 1005 by moving the apparatus along the x-15 axis. The rotation of the drive wheels 117 causes the cleaning apparatus to move along the fish netting along the y-axis. It will be understood that when the control module 1001 controls the drive mechanism 1003 to cause the drive wheels 117 to rotate in an anticlockwise direction, the cleaning apparatus is then caused to move in an opposite direction along the y-axis. 20

Figure 10B shows a further conceptual view of the operation of the cleaning system. This view is looking at the cleaning system from the side. That is, the view is looking along the y-axis. Here, the control module 1001 is causing the winch mechanism 113 to rotate in a clockwise direction as indicated by the arrow. 25 This causes the cable 115 to extend from the platform of the cleaning apparatus thus causing the cleaning head 111 to move away from the platform along the z-axis. It will be understood that when the control module 1001 controls the winch mechanism to rotate in an anticlockwise direction, the cable 115 is brought towards the platform of the cleaning apparatus and wraps around the rotary drum 30 of the winch and so causes the cleaning head 111 to approach the platform along the z-axis.

Meanwhile, during the movement of the cleaning head 111 along the z-axis, each of the cleaning head discs 701 emits high-pressure water that is directed towards 35 the netting 1005 to remove bio fouling. 11 2017100987 20 Μ 2017

The control module 1001 includes a processor which is adapted to develop control signals that automatically control the drive mechanism and winch mechanism. According to this embodiment, the processor is a programmable logic controller (PLC). However, it will be understood that the processor may be 5 any other suitable processor. The processor is caused to operate based on prestored instructions. These instructions cause the control module to develop control signals which cause the drive mechanism to rotate the drive wheels 117 and move the cleaning apparatus a predetermined distance along the netting, cause the winch mechanism to lower the cleaning head to a predetermined level 10 below the surface of the floating platform, move the drive mechanism to rotate the drive wheels 117 and move the cleaning apparatus again a predetermined distance along the netting, lift the cleaning head using the winch mechanism to a starting level and then repeating the above steps a predetermined number of times to clean a defined area of the netting. 15

The distance that the drive mechanism is caused to move by the control module is based on the width of the cleaning head 111. According to this embodiment, the notched wheels are hydraulically driven to turn slowly when triggered by the processor to index the whole unit across the net 1600 mm at a time. Once the 20 pontoon has stopped moving, the processor will start to pay out the winch wire attached to the cleaning head and the cleaning head is then lowered to a predetermined depth. The pontoon unit will then index across another 1600 mm and again the cleaning head will be winched to the surface. This represents one cycle with 3.2 metres of net cleaned. 25

Therefore, the herein described system provides a fully automatically controlled net cleaning system that has improved high-pressure water efficiency for cleaning bio fouling from netting. 30 Further Embodiments

It will be understood that the embodiments of the present invention described herein are by way of example only, and that various changes and modifications may be made without departing from the scope of invention. 35 2017100987 20 Μ 2017 12

For example, it will be understood that a standard high pressure water blaster pump may be used. This could be driven by or from the diesel engine to deliver approximately 100 L of seawater per minute at approximately 4000 psi in the most preferred form (it should be noted that these are preferred amounts, but not 5 necessarily the required amounts. Any pressure or volume sufficient to allow cleaning is suitable).

According to a further embodiment, the cleaning apparatus as described above in the first embodiment may not include a propeller mechanism. According to this 10 embodiment, the cleaning apparatus may be placed up against the netting so that the drive wheels are semi-permanently attached to the netting prior to use. Therefore, the propeller mechanism is not required to ensure the cleaning apparatus is constantly pushed against the netting. Upon completion of the net cleaning process, the cleaning apparatus may be detached from the netting 15 before being removed from the net cleaning area. For example, the toothed portions of the drive wheels may have a hook configuration to latch onto the netting.

Claims

CLAIMS:

1. A cleaning apparatus for cleaning under water netting comprising a floating platform, a winch mechanism, a drive mechanism, a control device, a high pressure water pump, and a cleaning head, wherein the control device includes a processor adapted to develop control signals for automatically controlling the drive mechanism and winch mechanism to cause the floating platform to move laterally across the netting, and further arranged to automatically control the winch mechanism to adjust the relative height of the cleaning head with respect to the floating platform, the high pressure water pump arranged to pump water at high pressure out of the cleaning head.
2. The apparatus of claim 1 wherein the cleaning apparatus further comprises a thrust propeller for driving the cleaning apparatus against the underwater netting.
3. The apparatus of claim 1 wherein the water pump system includes water hoses that have a length not exceeding 40 metres.
4. The apparatus of claim 3 wherein the water hoses have a length not exceeding 25 metres.
5. The apparatus of claim 4 wherein the water hoses have a length not exceeding 20 metres.
6. The apparatus of claim 1 wherein the drive mechanism is adapted to automatically move the floating platform upon receiving a control signal from the control device.
7. The apparatus of claim 1 wherein the drive mechanism comprises one or more drive wheels arranged to attach to the netting upon rotation of the drive wheels.
8. The apparatus of claim 7 wherein the drive wheels have a plurality of attachment points which are arranged to catch on to the netting upon rotation of the drive wheels.
9. The apparatus of claim 1 wherein the cleaning head comprises one or more cleaning head sections, wherein the cleaning head section comprises a water input port for attachment to the high pressure water pump system, and a water outlet for outputting the high-pressure water.
10. The apparatus of claim 1 wherein the winch mechanism is attached to the floating platform and comprises a rotary drum adapted to rotate upon receiving a control signal from the control device and a cable attached at a first end to the rotary drum wherein a second end of the cable is attached to the cleaning head.
11. The apparatus of claim 10, wherein the control signal causes the rotary drum to rotate a predefined distance in order to adjust the relative height of the cleaning head with respect to the floating platform.
12. The apparatus of claim 1 wherein the floating platform comprises a floating surface adapted to support the winch mechanism, drive mechanism, hydraulic water pump system and control device above the water level of the water upon which the floating surface is arranged to float.
14. The apparatus of claim any one of the preceding claims, wherein the processor is a programmable logic controller.
15. The apparatus of any one of claims 1 to 12, wherein the processor is further adapted to develop the control signals based on a pre-stored set of instructions.
16. The apparatus of claim 15, wherein the pre-stored set of instructions are adapted to develop the control signals in order to i) drive the drive mechanism a predetermined distance, ii) lower the cleaning head using the winch mechanism to a predetermined level below the surface of the floating platform, iii) repeat step i), iv) lift the cleaning head using the winch mechanism to a starting level, and repeat steps i) to iv) a predetermined number of times.
17. A cleaning apparatus as claimed in claim 1 wherein the drive mechanism has at least one drive wheel which is connected to the cleaning apparatus so as to rotate around an axis substantially parallel to the netting and which has a plurality of pivoting fingers which sequentially index onto the netting and unlatch as the drive wheel rotates to cause the cleaning apparatus to move laterally across the netting.
18. A cleaning apparatus as claimed in claim 17 wherein the drive wheel is formed from at least one flat circular plate, each finger having a base portion and a net engaging portion, the base portion pivotally connected to the plate at or close to the circumferential perimeter of the plate in such a manner that the fingers can rotate or pivot in the same plane as the wheel, the net engaging portion extending outwards away from the plate.
19. A cleaning apparatus as claimed in claim 1 wherein the cleaning apparatus also has an air compressor and an umbilical air hose, the umbilical air hose connected between the air compressor and the cleaning head, the air compressor arranged to pump air at high pressure out of the cleaning head at substantially the same position as the high pressure water to envelop the high pressure water as the high pressure water exits the cleaning head.
20. The apparatus of claim 19 wherein the cleaning head comprises one or more cleaning head sections, and wherein each of the one or more cleaning head sections comprises a water input port for attachment to the high pressure water pump system, a water outlet for outputting the high-pressure water, an air inlet port which connects to the high pressure air coming from the high pressure air system, and an air outlet at substantially the same position as the water outlet for outputting the high-pressure air such that the high pressure air envelops the high pressure water as the high pressure water exits the cleaning head section.
21. The apparatus of claim 20 wherein each of the one or more cleaning head sections is a disc, having a centrally located water inlet port and air inlet port, at least one high-pressure water gallery emanating from the hub of the cleaning head disc towards the outer rim, the distal end of the gallery connected to a water jet configured so that high-pressure water exits the cleaning head disc causing thrust, at least one air gallery emanating from the hub of the cleaning head disc towards the outer rim, air entering the centre hub of the cleaning head disc via the air inlet port, and emanating from the hub to the circumferential perimeter via the air gallery, the air gallery having an exit configured such that the air is liberated proximate to the water jet nozzles in such a manner that an air pocket is created around and enveloping the water jet.
22. A cleaning apparatus for cleaning under water netting comprising a floating platform, a winch mechanism, a drive mechanism, a control device, a high pressure water pump, a high pressure air pump, and a cleaning head, wherein the control device is arranged to automatically control the drive mechanism to cause the floating platform to move laterally across the netting, and further arranged to automatically control the winch mechanism to adjust the relative height of the cleaning head with respect to the floating platform, the high pressure water pump arranged to pump water at high pressure out of the cleaning head, the high pressure air pump arranged to pump air at high pressure out of the cleaning head proximate to the high pressure water exiting the cleaning head in such a manner that an air pocket is created around and enveloping the high pressure water.
23. The apparatus of claim 22 wherein the water pump system includes water hoses that have a length not exceeding 40 metres.
24. The apparatus of claim 22 or claim 23 wherein the water pump system includes water hoses that have a length not exceeding 40 metres.
25. The apparatus of claim 22 wherein the water hoses have a length not exceeding 25 metres.
26. The apparatus of claim 22 or claim 23 wherein the air hoses have a length not exceeding 25 metres.
27. The apparatus of claim 22 wherein the water hoses have a length not exceeding 20 metres.
28. The apparatus of claim 22 or claim 23 wherein the air hoses have a length not exceeding 20 metres.
29. The apparatus of claim 22 wherein the drive mechanism is adapted to automatically move the floating platform upon receiving a control signal from the control device.
30. The apparatus of claim 22 wherein the drive mechanism comprises one or more drive wheels arranged to attach to the netting upon rotation of the drive wheels.
31. The apparatus of claim 30 wherein the drive wheels have a plurality of attachment points which are arranged to catch on to the netting upon rotation of the drive wheels.
32. The apparatus of claim 31 wherein the drive wheels are connected to the cleaning apparatus so as to rotate around an axis substantially parallel to the netting and have attachment points including a plurality of pivoting fingers which sequentially index onto the netting and unlatch as the drive wheel rotates to cause the cleaning apparatus to move laterally across the net.
33. The apparatus of claim 32 wherein the drive wheels are each formed from at least one substantially flat circular plate, each finger having a base portion and a net engaging portion, the base portion pivotally connected to the plate at or close to the circumferential perimeter of the plate in such a manner that the fingers can rotate or pivot in the same plane as the wheel, the net engaging portion extending outwards away from the plate.
34. The apparatus of claim 22 wherein the winch mechanism is attached to the floating platform and comprises a rotary drum adapted to rotate upon receiving a control signal from the control device and a cable attached at a first end to the rotary drum wherein a second end of the cable is attached to the cleaning head.
35. The apparatus of claim 34, wherein the control signal causes the rotary drum to rotate a predefined distance in order to adjust the relative height of the cleaning head with respect to the floating platform.
36. The apparatus of claim 22 wherein the floating platform comprises a floating surface adapted to support the winch mechanism, drive mechanism, hydraulic water pump system and control device above the water level of the water upon which the floating surface is arranged to float.
37. The apparatus of claim 22 wherein the control device comprises a processor adapted to develop control signals for automatically controlling the drive mechanism and winch mechanism.
38. The apparatus of claim 37, wherein the processor is a programmable logic controller.
39. The apparatus of claim 37, wherein the processor is further adapted to develop the control signals based on a pre-stored set of instructions.
40. The apparatus of claim 39, wherein the pre-stored set of instructions are adapted to develop the control signals in order to i) drive the drive mechanism a predetermined distance, ii) lower the cleaning head using the winch mechanism to a predetermined level below the surface of the floating platform, iii) repeat step i), iv) lift the cleaning head using the winch mechanism to a starting level, and repeat steps i) to iv) a predetermined number of times.
41. The apparatus of claim 22 wherein the cleaning head comprises one or more cleaning head sections, and wherein each of the one or more cleaning head sections comprises a water input port for attachment to the high pressure water pump system, a water outlet for outputting the high-pressure water, an air inlet port which connects to the high pressure air coming from the high pressure air system, and an air outlet at substantially the same position as the water outlet for outputting the high-pressure air such that the high pressure air envelops the high pressure water as the high pressure water exits the cleaning head section.
42. The apparatus of claim 41 wherein each of the one or more cleaning head sections is a disc, having a centrally located water inlet port and air inlet port, at least one high-pressure water gallery emanating from the hub of the cleaning head disc towards the outer rim, the distal end of the gallery connected to a water jet configured so that high-pressure water exits the cleaning head disc causing thrust, at least one air gallery emanating from the hub of the cleaning head disc towards the outer rim, air entering the centre hub of the cleaning head disc via the air inlet port, and emanating from the hub to the circumferential perimeter via the air gallery, the air gallery having an exit configured such that the air is liberated proximate to the water jet nozzles in such a manner that an air pocket is created around and enveloping the water jet.