AU721456B3 - Method of generating a treatment fluid - Google Patents

Description

P/00/012 28/5/91 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION PETTY PATENT Invention Title: Name of Applicant: Actual Inventor(s): Address for service: "Method of Generating a Treatment Fluid" Kerry Maxwell Scott Kerry Maxwell Scott and Maxwell Edney Scott WRAY ASSOCIATES 239 Adelaide Terrace Perth, WA 6000 Attorney code: WR Details of Associated Provisional Application No(s): PQ3032 23 September 1999 PQ4600 10 December 1999 The following statement is a full description of this invention, including the best method of performing it known to me:-

TITLE

"Method of Generating a Treatment Fluid" TECHNICAL FIELD This invention relates to a method of generating a treatment fluid.

BACKGROUND OF THE INVENTION The invention has been devised particularly, although not solely, for eradicating weeds in urban environments. The invention can, however, have other application, including, for example, treatment of ground soil for purposes such as sterilisation.

In relation to vegetation control, it is customary to rely on the application of chemicals. Controlling vegetation, and in particular weeds, in this way can, however, have an adverse affect on the environment, including the ground, the atmosphere, and life-forms in the vicinity.

A known form of vegetation control without the use of chemicals involves application of hot water to vegetation in order to kill it. This procedure has not proved particularly satisfactory as it is uneconomical owing to the slow rate at which hot water needs to be applied in order to be effective.

A somewhat related procedure involved the application of hot foam to the vegetation. This also has not proved to be particularly successful commercially as the presence of foam on the ground is not aesthetically pleasing and has potential for damaging effects on the environment.

Another proposal for vegetation control involves the application of hot air or flame to the vegetation. This procedure is not particularly effective as it in fact only scorches the exposed part of the vegetation and does not effectively kill the vegetation. It also has the potential to create a fire hazard.

It is against the above background, and the problems and deficiencies associated therewith, that the present invention has been developed.

SUMMARY OF THE INVENTION The treatment fluid may be used for controlling vegetation by application of the treatment fluid to the vegetation.

The treatment fluid may be used for sterilising soil by application of the treatment fluid to the soil. The fluid may also be used for sterilising a surface by application of the treatment fluid to the surface.

Preferably, the hot water and the compressed air are mixed in a mixing chamber in the nozzle, wherein the nozzle comprises an elongate body having the outlet at one end thereof and an inlet at the other end thereof to receive the water, the mixing chamber being defined between the inlet and the outlet, and a further inlet being provided through which the air is introduced into the mixing chamber.

Preferably, the compressed air is introduced into the mixing chamber along a flow path directed towards the outlet.

The body may be in the form of a lance which can be manually held and operated.

Preferably, the hot water is delivered to the lance along a flexible hot water line.

Preferably, the air under pressure is delivered to the lance along a flexible air line.

The apparatus may further include means for generating hot water for delivery to the nozzle, and means for generating compressed air for delivery to the nozzle.

Conveniently, the means for generating hot water and the means for generating hot air are electrically operable, and the apparatus further includes a power supply for providing electrical power to operate the means for generating hot water and the means for generating compressed air.

Conveniently, the air is introduced into the mixing chamber at a flow rate of between, 84.9 and 198.1 cubic decimetres per minute, and preferably at a rate of about 141.5 cubic decimetres per minute.

Conveniently, the hot water is at a temperature of about 1100 C and is introduced into the mixing chamber at a flow rate of 10 litres per minute to 15 litres per minute, with a flow rate of 13 litres per minute being preferred.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood by reference to the following description of one specific embodiment thereof as shown in the accompanying drawings in which: Figure 1 is a schematic view of apparatus used in performing the method according to the embodiment; and Figure 2 is a schematic view of a lance which forms part of the apparatus of Figure 1.

BEST MODE(S) FOR CARRYING OUT THE INVENTION The embodiment shown in the drawings is directed to a method of generating a treatment fluid which can be used for various purposes, one of which is vegetation control and another of which is sterilisation of topsoil.

The method is performed using apparatus 10 which comprises a mobile structure (not shown) carrying a supply of hot water 11 and a reservoir 12 for replenishing water extracted from the supply 11. The mobile structure also supports an air compressor 15 for providing a supply of compressed air. The supply of hot water 11 and the air compressor 15 are both electrically operable and receive electrical power from a power supply 17 which is also carried on the mobile structure.

The apparatus further includes a nozzle in the form of a hand-held lance 21 which is controlled by an operator working in association with the mobile structure. The lance 21 is connected to the hot water supply 11 by way of a flexible hot water delivery line 23. The lance 21 is also connected to the air compressor 15 by way of a flexible air line As is seen in Figure 2 of the drawings, the lance 21 comprises an elongate body 31 of generally circular cross section. One end of the body 31 has an inwardly tapering spout section 33 terminating at a discharge outlet 35. The other end of the body 31 is provided with a first inlet 37 to which the hot water delivery line 23 is connected.

A mixing chamber 39 is defined within the body 31 between the ends thereof.

A second inlet 41 opens into the mixing chamber 39. The second inlet 41 is defined by an end section 42 of the air delivery hose 25 which extends through the side wall 43 of the body 31. The end section 42 is arranged so as to direct air issuing from the inlet 41 in a direction towards the outlet 35, as shown in Figure 2 of the drawings.

-6- In this embodiment, compressed air is delivered into the mixing chamber 39 along the air delivery line 25 at a rate of between 84.9 and 198.1 cubic decimetres per minute, with the preferred rate being 141.5 cubic decimetres per minute. Water at a temperature of about 1000 C is delivered from the supply 11 into the mixing chamber 39 along water delivery line 23 at a rate of between litres per minute and 15 litres per minute, with a rate of 13 litres per minute being preferred.

The mixing chamber 39 has an external diameter of about 19 millimetres and an internal diameter of about 75% of the external diameter. The length is between 750 millimetres and 1 metre. The outlet 35 in the spout section 33 is in the form of a hole of a diameter of about 1.5 millimetres.

In operation, hot water and air delivered separately to the lance 21 are mixed together in the treatment chamber 39 to form a treatment fluid which discharges under pressure through the outlet 35. The operator controls the direction of the discharging treatment fluid by manipulating the lance 21 as necessary.

The treatment fluid can be used for vegetation control in which case the treatment fluid is sprayed onto the vegetation which is to be killed.

In another application, the treatment fluid can be used to sterilise topsoil, in which case the treatment fluid is simply sprayed onto the soil requiring treatment.

The combination of hot water and compressed air forming the treatment fluid provides unexpected results in its effectiveness in vegetation control and sterilisation. It is believed that the presence of moisture in the treatment fluid is very effective in delivery of heat to the vegetation or soil, and assists in penetration of the heat into the plant structure of the vegetation and also in the soil.

While the combination of the hot water and the air under pressure when mixed AL gether provides a treatment fluid which is particularly effective in vegetation trol and soil sterilisation, it should be appreciated that the treatment fluid may necessarily be limited to such applications.

-7- It should also be appreciated that the scope of the invention is not limited to the scope of the embodiment described.

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

Claims (3)

1. A method of generating a treatment substance comprising steps of: creating a supply of hot water; creating a supply of compressed air; delivering a stream of the hot water at a rate of between 10 to 15 litres per minute and a stream of the compressed air at a rate of between 84.9 and 198.1 cubic decimetres per minute to a nozzle in which the hot water and the compressed air are mixed to create a treatment fluid; and discharging the treatment fluid under pressure through an outlet in the nozzle.

2. A method according to claim 1 wherein the hot water and the compressed air are mixed in a mixing chamber in the nozzle, wherein the nozzle comprises an elongate body having the outlet at one end thereof and an inlet at the other end thereof to receive the water, the mixing chamber being defined between the inlet and the outlet, and a further inlet being provided through which the air is introduced into the mixing chamber.

3. A method according to claim 2 wherein the compressed air is introduced into the mixing chamber along a flow path directed towards the outlet. Dated this TWENTY-SEVENTH day of APRIL 2000. Kerry Maxwell Scott Applicant Wray Associates Perth, Western Australia Patent Attorneys for the Applicant