This invention has particular application to a method of removing debris from waterways and to apparatus therefor.

As used herein the expression"debris"is to be given a broad meaning and refers to all debris, including biomass debris whether vegetative or not, and whether floating, suspended or sunken in the waterway.

The invention will be seen to have most particular application to a method of and apparatus for removing vegetation from waterways.

Background of Invention It is known for floating biomass and debris to be removed from waterways manually or by means of conveyor belts.

Summary of Invention The present invention aims to provide an alternative to known methods of and apparatus for removing debris from waterways.

This invention in one aspect resides broadly in an apparatus for removing debris from a waterway, the apparatus including:- a propellable floating vessel; pumping means operable to establish a venturi effect to create an aquatic vacuum; inlet means operable from the floating vessel for applying the aquatic vacuum to the debris to create a flow of water carrying the debris through pipe means or the like connected to the inlet means, and sieving collector means positionable in the waterway whereby the debris is retained in the sieving collector means when the flow of water carrying the debris is

passed therethrough, the seiving collector means being releasably affixale to the floating vessel whereby the sieving collector means is removable from the waterway independent of the floating vessel for emptying away from the waterway.

In a preferred embodiment the apparatus includes trailer means adapted to transport the floating vessel and/or the sieving collector means to and/or from the waterway.

It is preferred that the pumping means is located on the floating vessel.

In an embodiment not illustrated, the sieving collector means is buoyed by the floating vessel. However it is preferred that the sieving collector means includes flotation means.

It is also preferred that the sieving collector means is towable by the floating vessel.

It is also preferred that the sieving collector means includes deflection means mounted on the sieving collector means against which the flow of water carrying the debris can be directed to thereby maintain separation between the sieving collector means and the propelled floating vessel during operation.

It is also preferred that the sieving collector means includes release means operable to releases debris retained in the sieving collector means therefrom.

It is also preferred that the trailer means includes tipping means for tipping the sieving collector means when mounted thereon to a position such that the debris retained therein is released therefrom.

It is also preferred that the sieving collector means includes a basket-like cage adapted to sieve the debris.

It is also preferred that the basket-like cage is inversely mounted on a low draught punt.

It is also preferred that the flotation means includes pontoon means mounted on the cage to maintain buoyancy of the sieving collector means when the low draught punt is submerged.

It is also preferred that the release means is a gate or the like hinged to the cage and opening from the floor of the punt.

In another aspect this invention resides broadly in a method of removing debris from a waterway, the method including:- creating an aquatic vacuum;

applying the aquatic vacuum to the debris to create a flow of water carrying the debris; passing the flow of water carrying the debris through sieving collector means positioned in the waterway whereby the debris is removed from the flow of water and retained in the sieving collector means, and removing the sieving collector means containing the debris from the waterway.

In a preferred embodiment the aquatic vacuum is created by pumping means operable to establish a venturi effect.

It is preferred that the pumping means is located in a propelled floating vessel.

It is also preferred that the sieving collector means includes flotation means.

It is also preferred that the method includes towing the sieving collector means behind the propelled floating vessel.

It is also preferred that the method includes directing the flow of water carrying the debris against deflection means mounted on the sieving collector means to thereby maintain separation between the sieving collector means and the propelled floating vessel during operation.

It is also preferred that the sieving collector means is removed from the waterway by being winched on to trailer means adapted to transport the floating vessel and/or the sieving collector means to and/or from the waterway. Alternatively, in an embodiment not illustrated, the sieving collector means can be amphibious and have wheels or the like for direct transportation to a debris disposal site.

Description of Drawings In order that this invention may be more easily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention, wherein:- FIG 1 is a plan view of the assembly showing the operating vessel and the collecting cage mounted on the trailer for travel to or from the waterway; FIG 2 is a side elevation of the assembly seen in FIG 1; FIG 3 is a plan view of the operating vessel with the connections of the venturi and pump shown in more detail in side views in FIGS 3A and 3B respectively;

FIGS 4A and 4B are side and plan views respectively of the collecting cage with the venturi shown in increasingly more detail in FIGS 4C and 4D; FIG 5 is a side elevation of the collecting cage mounted on the trailer for removal from the waterway to dispose of a load of debris, and FIG 6 is a side elevation of the collecting cage when elevated on the trailer for removal of debris therefrom.

Description of Preferred Embodiment of Invention As can be seen in the drawings, apparatus 10 in accordance with the present invention for removing debris from a waterway has a propellable floating vessel in the form of boat 11, pumping means in the form of a pump 12 operable by means of venturi 13 to establish a venturi effect to create an aquatic vacuum, inlet means 14 in the form of tube 15 and collection nozzle 16 operable from boat 11 for applying the aquatic vacuum to the debris to create in outlet 17 a flow of water carrying the debris, and sieving collector means 18 in the form of cage 19 mounted on a shallow draught punt 20.

Sieving collector means 18 is positionable in the waterway whereby the debris is retained in the sieving collector means when the flow of water carrying the debris is passed therethrough.

Inlet means 14 can comprise a length of aluminium pipe in the hull of boat 11 as best seen in FIG 3, with two flexible pipes or hoses connected thereto. One at the bow end constitutes collector nozzle 16 and the other 30 at the stern end is connected to the suction tube end of venturi 13.

Trailer means in the form of trailer 21 is adapted to transport boat 11 and/or sieving collector means 18 to and/or from the waterway. Pump 12 is mounted on the side of boat 11 and pumps water via footvalve 28 through flexible hose 29 to venturi 13.

Cage 19 includes flotation means in the form of pontoons 22 mounted high on the cage and sieving collector means 18 includes a towing hitch so as to be towable by boat 11.

Venturi 13 is supported on the bow of punt 20 by cradling in mounting bracket 23 for directing the flow of water containing the debris into cage 19.

Sieving collector means 18 also includes deflection means in the form of an angled deflection plate 24 mounted thereon such that when a flow of water carrying the debris is directed thereagainst, the debris is deflected into the lower portion of the cage

and the action of the flow against plate 24 serves to maintain separation between sieving collector means 18 and boat 11 during operation when the action of the venturi, which is attached to the sieving collector means, can have a jet effect propelling it towards the boat.

Sieving collector means 18 has release means in the form of gate 26 hinged to the upper portion of cage 19 and opening away from the floor of punt 20 and which is operable when the sieving collector means 18 is positioned on trailer 21 as seen in FIGS 6 and 7 to discharge debris therefrom. Trailer 21 has tipping means in the form of hoist 26 and winch 27 for tipping sieving collector means 18 when mounted on the trailer.

A more detailed description of a preferred embodiment of the invention is now provided.

The invention uses massive water pressure to create a vacuum which facilitates the drawing up of matter from the surface, or below the surface, of a waterway through a length of hose-such matter then being contained within a basket.

The required water pressure is created by a motor driving a centrifugal pump.

The vacuum is created by a venturi. Attached to the venturi is a length of hose, the other end of which is a collection nozzle. This combination of equipment forms an aquatic vacuum device. The device is housed within a boat and is connected to a collection receptacle.

The floating vessel illustrated is a 5 metre, V-nosed, flat-bottomed boat powered by a 90 h. p. outboard motor. This type of hull has the necessary shallow draft required to navigate areas which larger craft cannot access. The hull is fitted with a length of 125 mm outside/diameter aluminium pipe (3mm wall thickness) laid in the floor. A length of 125mm inside/diameter flexible hose is clamped onto this pipe where it exits the bow. Fitted with a metal clamp and guide-rod, this end becomes the collection nozzle. A length of 125mm inside/diameter flexible hose is clamped onto the pipe where it exits the boat's transom. A 4 x 3 centrifugal pump, driven by an 11 h. p. motor is housed within the boat. The pump's 75mm water delivery spigot exits the boat at the transom. A length of 75mm inside/diameter flexible hose is clamped onto the spigot. The pump's 100mm water-intake exits the boat at the starboard side above water level. A self-priming foot-valve is fitted to the water-intake.

The collection receptacle illustrated is a 3. 4m x 2.4m aluminium-framed, wire mesh basket, mounted on a custom aluminium punt with towing hitch. A support bracket is located at the bow of the collection receptacle. The venturi is attached via a bayonet fitting. The flexible hose connected to the hull pipe at the transom is clamped onto the venturi suction tube, whilst the hose connected to the pump is clamped onto the venturi jet-log. The top bar at the bow is fitted with a deflector plate which prevents forward motion of the collection receptacle. Flotation pontoons are attached port and starboard. At the stern of the collection receptacle is a swinging gate which opens up from the floor of the punt.

The trailer illustrated is a 9.8m tandem trailer with disc-brakes. In addition to transporting both the boat and the collection receptacle, the trailer is used to retrieve the collection receptacle from the water for emptying. The boat winch is used to retrieve the collection receptacle from the water. Dolly-wheels are positioned at the rear end of the trailer to provide stability when emptying the collection receptacle.

In use, debris is removed from waterway in accordance with the present invention by creating an aquatic vacuum (by pump 12 and venturi 13), applying the aquatic vacuum (by tube 15 and collection nozzle 16) to the debris to create a flow of water carrying the debris, passing the flow of water carrying the debris (by outlet tube 17) through sieving collector means 18 positioned in the waterway whereby the debris is removed from the flow of water and retained in the sieving collector means, and then removing sieving collector means 18 containing the debris from the waterway.

In the preferred embodiment illustrated pump 12 is located in a propelled boat 11 which tows sieving collector means 18 which is in the form of a cage 19 mounted on a shallow draught punt 20 and having pontoons 22 for buoyancy. The flow of water in outlet pipe 17 is directed against deflection plate 24 to thereby separate sieving collector means 18 from boat 11 during operation.

When full of debris, sieving collector means 18 is removed from the waterway by being winched on to trailer 21 and the debris is removed therefrom as described above.

Thus in general terms the boat tows the collector to the area to be cleaned. The hoses are attached and the pump is started to create the vacuum and the collector nozzle is positioned adjacent the debris to be removed. Water and debris are thus drawn into the collection nozzle and both travel through the pipe in the boat hull. Both water and

debris are deposited into the cage-like collector which becomes partially submerged.

When full, the collector is disconnected from the venturi and hoses and towed by the boat to a position near the waterway bank where it is retrieved from the water by being winched onto a trailer. The collector is then emptied as described above and the process is then repeated.

It will be appreciated that the method and apparatus of the present invention has a number of advantages over known apparatus and methods of clearing waterways of debris, especially vegetation such as water weed. In particular, the rig is completely transportable and the adaptability of the trailer and collector allow for easy disposal of the debris at a chosen location thereby avoiding the environmental damage and degradation which the banks of a waterway can suffer if debris is pumped onto the bank in a dredging-type operation. Furthermore, if the wheels on the trailer are replaced or supplemented by drive-tracks, the rig can operate in areas where there is no boat ramp.

It will of course be realised that whilst the above has been given by way of an illustrative example of this invention, all such and other modifications and variations hereto, as would be apparent to persons skilled in the art, are deemed to fall within the broad scope and ambit of this invention as is herein set forth.