Patent Description:
Agricultural sprayers are used in the application of various materials to field crops. Such systems apply various chemicals in the form of a spray for the purposes of crop protection, e.g. through the use of appropriate pesticides or herbicides, or for the purposes of promoting plant growth, e.g. through use of liquid plant fertiliser. Agricultural sprayers may be provided as self-propelled sprayers, or as systems to be mounted to an agricultural tractor, e.g. as a towed or hitch-mounted implement.

One of the primary concerns in the use of potentially harmful chemicals such as pesticides or fertilisers is that proper cleaning and maintenance of sprayers is necessary to avoid injury to non-target crop species, e.g. through the incorrect application of residual chemicals from a preceding sprayer operation. Accordingly, sprayer operators must pay close attention to proper cleaning and sterilisation procedures, to prevent contamination or injury to crops or to the environment in general.

Such cleaning procedures often require the rinsing of the sprayer systems with a large volume of rinse water and/or chemical cleaning solution to ensure safe concentration levels in the sprayer. However, such excessive use of water and cleaning solutions can be relatively wasteful, as well resulting in increased cost levels for sprayer operators. In addition, sprayers can often be required to return to a centralised depot for a cleaning operation, if the relatively large volumes of rinse water or cleaning solutions are too bulky to transport with the sprayer itself.

<CIT> discloses an unmanned spray system that uses water in a nozzle washing process after a spray operation. <CIT> discloses an ozone system for agricultural applications wherein ozone is applied to crops using spraying apparatus. <CIT> discloses another system for treating crops with ozone.

It is an object of the invention to provide an agricultural sprayer and a method of operating such a sprayer having an improved sprayer cleaning process.

Accordingly, there is provided a method of operating an agricultural sprayer, the agricultural sprayer comprising a liquid tank to hold a spray liquid and a spray applicator system coupled to the liquid tank, the method comprising the steps of:.

The use of ozone allows for a relatively simple and cost-effective mechanism for the cleaning of agricultural sprayers as well as the sterilisation of the spay liquid used in such sprayers. It will be understood that the spray liquid may comprise a fertiliser chemical, or any known pesticide, herbicide or fungicide used for crop protection. It will be understood that the spray liquid itself does not comprise ozone.

Preferably, the method comprises the step of generating ozone using an ozone generator for supply to the at least a portion of the agricultural sprayer.

The sprayer may be provided with an on-board ozone generator, to produce ozone on site during or immediately after a spraying operation. The use of an on-board generator eliminates the need to transport cleaning material storage containers with the sprayer itself, and allows for a more efficient design of the sprayer system, resulting in reduced weight and size, and providing improved flexibility to perform sprayer cleaning operations. Such an ozone generator may comprise any suitable generator design, e.g. a corona discharge method generator, an ultraviolet light generator, a cold plasma generator, and electrolytic generator.

Additionally or alternatively, the method comprises the step of supplying ozone from an ozone supply tank provided on the agricultural sprayer.

The sprayer may be provided with an ozone storage tank arranged to hold ozone for use in sprayer cleaning operations. Such a storage tank may be filled with ozone using an on-board ozone generator, e.g. in parallel to a spraying operation, to ensure immediate supply of a pre-generated volume of ozone when a cleaning operation is requested. Additionally or alternatively, the storage tank may be filled with ozone by connection to a separate central ozone generator, e.g. prior to the sprayer leaving a central depot for a field spraying operation.

Preferably, the method comprises the step of supplying ozone to at least a portion of the spray applicator system, to clean at least a portion of the spray applicator system.

Preferably, the spray applicator system comprises a nozzle array arranged along a length of at least one spray boom, and sprayer plumbing connecting the nozzle array with the liquid tank, wherein the method further comprises the step of supplying ozone to the spray applicator system at discrete locations along the length of the spray boom.

By supplying ozone at spaced locations along the length of the sprayer boom, accordingly it is ensured that a safe concentration of ozone is provided at all locations along the boom.

Preferably, the method comprises the step of injecting ozone into the sprayer plumping at discrete locations along the length of the spray boom.

Alternatively, ozone may be injected at a single location on the boom, wherein turbulence in the fluid stream may be utilised to sufficiently mix the ozone into the fluid stream. It will be understood that suitable baffles may be provided in the spray plumbing in order to increase the mixing rate of the ozone in the fluid stream.

Preferably, the method further comprises the step of rinsing at least a portion of the spray applicator system using a rinse fluid after the spraying operation is complete, to at least partly rinse the spray applicator system of spray liquid.

It will be understood that the step of rinsing comprises circulating a fluid in the spray applicator system, preferably through the sprayer plumbing while the nozzle array is closed, to ensure fluid flow throughout the spray applicator system. The ozone can then be supplied to the fluid during such a circulation stage, to effectively cleanse the interior of the spray applicator system.

Preferably, the step of rinsing comprises supplying rinse water from a rinse water tank provided on the agricultural sprayer.

Additionally or alternatively, the step of rinsing comprises supplying compressed air from a compressed air supply device provided on the agricultural sprayer.

In a preferred embodiment, the method comprises the steps of:.

It will be understood that, in the step of supplying compressed air to flush the spray applicator system, spray liquid contained in the spray applicator system may be flushed to ground or to an auxiliary tank. This ensures that the residual spray liquid in the spray applicator system is minimised, which reduces the cleaning effort required to effectively clean or sterilise the spray applicator system.

In one aspect of the invention, the sprayer comprises an auxiliary liquid tank arranged to receive residual spray liquid from the spray applicator system after a spraying operation, and wherein the method comprises the step of supplying ozone to the auxiliary liquid tank from the ozone supply to sterilise the residual spray liquid in the auxiliary tank.

By providing an auxiliary tank to receive residual spray liquid after a spraying operation, the act of cleaning or sterilising the chemicals in the residual spray liquid can be confined to the auxiliary tank, thereby allowing further operations to be performed while the residual spray liquid is being cleansed.

In a preferred embodiment, where the sprayer comprises an auxiliary liquid tank, the method comprises the further steps of:.

By rinsing, draining, or flushing the first spray liquid to the auxiliary liquid tank, the cleaning or sterilisation of the residual spray liquid can be performed in the auxiliary tank, such that the spray applicator system is then free to be used for a second spraying
operation at the same time as the initial cleaning operation. This allows for more efficient use of the sprayer, as further spraying operations can be performed in parallel with the cleaning process required from a preceding spraying operation, using a different chemical spray liquid.

Preferably, the step of supplying ozone to clean at least a portion of the agricultural sprayer is performed until a chemical concentration of spray liquid is reduced to a safe level.

In one aspect, the step of supplying ozone is performed for a predetermined length of time to ensure a safe concentration of spray liquid is achieved.

The sprayer may be provided with predetermined time durations and/or chemical concentration levels, to ensure that a cleaning operation is performed until the spray applicator system is sufficiently clean and/or the residual spray liquid is sufficiently sterilised.

In an additional or alternative aspect, the method comprises the steps of:.

Additionally or alternatively, the method may comprise the further step of receiving a user-defined time duration or chemical concentration level, from a user input device.

There is further provided an agricultural sprayer comprising:.

The use of ozone allows for a relatively simple and cost-effective mechanism for the cleaning of agricultural sprayers as well as the sterilisation of the spay liquid used in such sprayers. It will be understood that the spray liquid may comprise any known pesticide, herbicide or fungicide used for crop protection, or any suitable liquid fertiliser. Preferably, the agricultural sprayer comprises a self-propelled sprayer apparatus, but it will be understood that the invention may also apply to a tractor-mounted spray system, e.g. for use as a hitch-mounted implement or as a towed sprayer system.

Preferably, the ozone supply comprises an ozone generator provided as part of the agricultural sprayer.

Additionally or alternatively, the ozone supply comprises an ozone tank to hold ozone, the ozone tank provided as part of the agricultural sprayer, and coupled with the spray applicator system.

In one aspect, the ozone supply is arranged to supply ozone to at least a portion of the spray applicator system.

Preferably, the spray applicator system comprises:.

Preferably, the ozone supply is configured such that ozone is supplied to the spray applicator system at discrete locations along the length of the spray boom.

Preferably, the ozone supply comprises a plurality of ozone injectors, wherein the ozone injectors are arranged to inject ozone into the sprayer plumbing at discrete locations spaced along the length of the spray boom.

Preferably, the agricultural sprayer comprises a rinse fluid supply arranged to supply a rinse fluid to the spray applicator system after a spraying operation, to at least partly rinse the spray applicator system of spray liquid.

The rinse fluid may comprise any fluid suitable for the purpose of rinsing a spray liquid from a spray applicator system, e.g. rinse water and/or compressed air or other gas.

In one aspect, the rinse fluid supply comprises a rinse water tank to hold rinse water.

Additionally or alternatively, the rinse fluid supply comprises an air supply, preferably a compressed air supply device.

In an additional or alternative aspect, the agricultural sprayer further comprises an auxiliary liquid tank arranged to receive residual spray liquid from the spray applicator system after a spraying operation, wherein ozone is provided to the auxiliary liquid tank from the ozone supply to sterilise residual spray liquid contained in the auxiliary tank.

Preferably, the sprayer is configured to perform a cleaning operation in the auxiliary liquid tank using ozone supplied to the auxiliary liquid tank on a first residual spray liquid from a first spraying operation, wherein the cleaning operation is performed in parallel with a second spraying operation performed using second spray liquid supplied from a liquid tank to the spray apparatus.

Preferably, the sprayer is configured such that ozone is supplied for a predetermined length of time to ensure a safe concentration of residual spray liquid is achieved.

Additionally or alternatively, the sprayer comprises at least one chemical concentration sensor arranged to detect the level of chemical concentration in residual spray liquid in the spray applicator system, wherein the sprayer is configured such that ozone is supplied until a safe chemical concentration level of residual spray liquid is achieved.

Additionally or alternatively, the sprayer comprises a user input device arranged to receive a user-defined time duration or chemical concentration level, from a user input device.

The agricultural sprayer further comprises a controller coupled with the spray applicator system and with the ozone supply, the controller arranged to implement the steps of the method as described above.

<FIG> shows an agricultural crop sprayer <NUM> used to deliver chemicals to agricultural crops in a field. Agricultural sprayer <NUM> comprises a chassis <NUM> and a cab <NUM> mounted on the chassis <NUM>. Cab <NUM> may house an operator and a number of controls for the agricultural sprayer <NUM>. An engine <NUM> may be mounted on a forward portion of chassis <NUM> in front of cab <NUM> or may be mounted on a rearward portion of the chassis <NUM> behind the cab <NUM>. The engine <NUM> may comprise, for example, a diesel engine or a gasoline powered internal combustion engine. The engine <NUM> provides energy to propel the agricultural sprayer <NUM> and also can be used to provide energy used to spray fluids from the sprayer <NUM>.

Although a self-propelled application machine is shown and described hereinafter, it should be understood that the embodied invention is applicable to other agricultural sprayers including pull-type or towed sprayers and mounted sprayers, e.g. mounted on a <NUM>-point linkage of an agricultural tractor.

The sprayer <NUM> further comprises a liquid storage tank <NUM> used to store a spray liquid to be sprayed on the field. The spray liquid can include chemicals, such as but not limited to, herbicides, pesticides, and/or fertilizers. Liquid storage tank <NUM> is to be mounted on chassis <NUM>, either in front of or behind cab <NUM>. The crop sprayer <NUM> can include more than one storage tank <NUM> to store different chemicals to be sprayed on the field. The stored chemicals may be dispersed by the sprayer <NUM> one at a time or different chemicals may be mixed and dispersed together in a variety of mixtures. The sprayer <NUM> further comprises a rinse water tank <NUM> used to store clean water, which can be used for storing a volume of clean water for use to rinse the plumbing and main tank <NUM> after a spraying operation.

At least one boom arm <NUM> on the sprayer <NUM> is used to distribute the fluid from the liquid tank <NUM> over a wide swath as the sprayer <NUM> is driven through the field. The boom arm <NUM> is provided as part of a spray applicator system, which further comprises an array of spray nozzles <NUM> (<FIG>) arranged along the length of the boom arm <NUM> and suitable sprayer plumping <NUM>,<NUM> (<FIG>) used to connect the liquid storage tank <NUM> with the spray nozzles <NUM>. The sprayer plumping will be understood to comprise any suitable tubing or piping arranged for fluid communication on the sprayer <NUM>.

A spray applicator system according to one aspect of the invention is illustrated in a schematic outline in <FIG> at <NUM>. In the illustrated embodiment, the liquid tank <NUM> and the rinse water tank <NUM> are connected with a valve system <NUM>, which can controls the supply of liquid from either of the tanks <NUM>,<NUM>, and/or the direction of flow. The valve system <NUM> can comprise any suitable configuration of valve elements, e.g. a single multi-port valve element, or an array of individual elements.

The valve system <NUM> is connected with the nozzles <NUM> of the boom arm <NUM> via a feed line or channel <NUM> of the sprayer plumbing. A further recirculation channel or return channel <NUM> extends from the boom arm <NUM> to the valve system <NUM>, allowing for a recirculation of liquid in the spray applicator system <NUM>. The system further comprises a pump <NUM> which acts to circulate liquid from either of the tanks <NUM>,<NUM> through the sprayer plumbing. The pump <NUM> can be driven by the engine <NUM> or any other suitable power source. An example of the relationship between the tank and pump of a suitable spray applicator system can be found in <CIT>, the disclosure of which is incorporated by reference herein.

In the illustrated embodiment of the invention, the spray applicator system <NUM> further comprises a compressed air supply <NUM>, e.g. a compressed air pump, which is coupled with the valve system <NUM> to provide for selective supply of compressed air to various sections of the sprayer plumbing. It will be understood that other embodiments of the invention may omit the use of the compressed air supply <NUM> from the spray applicator system <NUM>.

The spray applicator system <NUM> further comprises an electronic control unit (ECU) <NUM>, which is configured to control the operation of the various components of the system, e.g. the valve system <NUM>, the pump <NUM>, the compressed air supply <NUM>, and the components of the boom arm <NUM> including the spray nozzles <NUM> and the boom arm <NUM> position. The ECU <NUM> can operate in response to commands issued by an operator in the sprayer cab <NUM>, or based on pre-programmed operating routines, which may be triggered by operator action.

The spray applicator system <NUM> further comprises an ozone supply <NUM>. The ozone supply <NUM> may be provided as an ozone generator located on the sprayer <NUM> itself, and may comprise any suitable ozone generator design, e.g. a corona discharge method generator, an ultraviolet light generator, a cold plasma generator, and electrolytic generator. Additionally or alternatively, the ozone supply <NUM> may be provided as an on-board storage tank located on the sprayer <NUM>, the ozone storage tank arranged to supply ozone to the sprayer <NUM>. Such a storage tank may be used to temporarily store ozone generated by an on-board ozone generator, or to receive ozone from a separate ozone generator just prior to the sprayer leaving a central depot to perform a spraying operation.

The ozone supply <NUM> may be operated by the ECU <NUM>, and is configured to supply ozone to at least a portion of the spray applicator system <NUM>, in order to clean and sterilise residual spray liquid and/or the spray applicator system <NUM>, after a spraying operation has completed.

Ozone is a relatively strong oxidant and disinfectant which is suitable for the treatment of aqueous solutions and gaseous mixtures, which is partially soluble in water. Accordingly, ozone is particularly suitable for the cleaning of the internal tubing and plumbing of a crop sprayer. In addition, after ozone oxidizes or disinfects, it decomposes into oxygen, leaving no harmful by-products. As a result, the use of an ozone supply to perform a cleaning operation of a crop sprayer presents a simple, cost-effective, and safe cleaning system for a crop sprayer, which can be relatively easily incorporated into existing sprayer designs.

A method for use with the embodiment of <FIG> is now described, with reference to the process illustrated in <FIG>. After start of the sprayer <NUM>, step <NUM>, a spraying operation is performed, step <NUM>, wherein spray liquid is supplied from the liquid tank <NUM> via the valve system <NUM> and the feed line <NUM> to the boom arm <NUM>, for application as a spray from the spray nozzles <NUM>. When the spraying operation is completed, step <NUM>, the valve system <NUM> shuts off the supply of spray liquid to the boom arm <NUM>. At this point, the ECU <NUM> is configured to start a cleaning operation of the spray applicator system <NUM>.

The ECU <NUM> commands the array of spray nozzles <NUM> to close, such that the spray applicator system <NUM> can be put into recirculation mode, step <NUM>. The ECU <NUM> then configures the valve system <NUM> such that clean rinse water can be supplied from the rinse water tank <NUM> to the spray plumbing <NUM>,<NUM> and the boom arm <NUM>, and can be recirculated through the associated tubing using the pump <NUM>, step <NUM>.

As rinse water is being circulated in the plumbing, the ECU <NUM> instructs the ozone supply <NUM> to inject ozone into the recirculating fluid, step <NUM>. The ozone is supplied such that the concentration level of ozone in the recirculating fluid acts to ensure that the interior of the spray applicator system <NUM> is cleaned of all hazardous or undesirable substances, and that the chemical concentration of any remaining spray liquid is reduced to a safe level. The ECU <NUM> is then arranged to stop the recirculation mode, and to allow the safe liquid to be drained or flushed from the spray applicator system, step <NUM>, ready for a further spraying operation.

It will be understood that the sprayer <NUM> may comprise at least one chemical sensor arranged to detect the chemical concentration of the recirculating fluid, wherein the ECU <NUM> is configured to continue the recirculation of the rinse water and ozone until the detected concentration level is reduced to a safe level. Additionally or alternatively, the ECU <NUM> is configured to maintain recirculation of the rinse water and ozone for a predefined time period, to ensure that all concentration levels are reduced to a safe level.

It will be further understood that the concentration levels and/or time periods may be adjustable, either by the sprayer operator, or based on the type and/or concentration of spray liquid used in the spray applicator system <NUM>.

The ozone may be injected from the supply <NUM> into the circulating liquid at a single location, but in a preferred embodiment, the spray applicator system <NUM> is configured such that the ozone supply <NUM> can inject ozone into the circulating liquid at a plurality of different locations. Such distributed injection of ozone ensures that an effective concentration of ozone is supplied at all locations of the spray applicator system <NUM>, in particular in the spray plumbing of the system. In the illustrated embodiment of <FIG>, the ozone supply <NUM> is configured to inject ozone into the spray plumbing at a number of locations spaced along the length of the boom arm <NUM>.

In a preferred embodiment, where the spray applicator system <NUM> comprises a compressed air supply <NUM> as shown in <FIG>, an additional step may be performed between the end of the spraying operation (<NUM>) and the start of the recirculation mode (<NUM>). In this case, when the spraying operation has completed, the ECU <NUM> instructs the air supply <NUM> and the connected valve system <NUM> to supply compressed air to the spray plumbing <NUM>,<NUM>, step <NUM>, such that residual spray liquid remaining in the plumbing system after the spray operation can be blown out through the nozzles <NUM> to ground. This acts to reduce the volume of fluid to be cleansed from the system. Once the compressed air has been cycled through the spray applicator system <NUM>, the ECU <NUM> can then shut off the compressed air supply <NUM>, before continuing the remainder of the process by entering the recirculation mode as described above for step <NUM>.

A further embodiment of spray applicator system is illustrated in <FIG>, where elements in common with the embodiment of <FIG> are provided with the same reference numerals. In the embodiment of <FIG>, the spray applicator system <NUM> is provided with an auxiliary liquid tank <NUM>, which is connected to the valve system <NUM>. The auxiliary liquid tank <NUM> is arranged to receive a fluid to be cleaned after a spraying operation, wherein the ozone supply <NUM> is configured to supply ozone to the auxiliary tank <NUM> to clean any such contained fluid. The spray applicator system <NUM> may be provided with an additional liquid tank <NUM>, to store an additional spray liquid for use in a second spraying operation, as described below.

While the embodiment of <FIG> shows the ozone supply <NUM> connected with the auxiliary liquid tank <NUM>, it will be understood that the features of the embodiments of <FIG> and <FIG> may be combined, such that the ozone supply <NUM> is configured to be connected with both an auxiliary liquid tank <NUM> and the sprayer boom arm <NUM>. In addition, while the schematic outlines of <FIG> and <FIG> show a single boom arm <NUM>, it will be understood that the sprayer <NUM> may be provided with a plurality of separate boom arms and associated spray nozzles and plumbing.

With reference to <FIG>, a method of operation of the system illustrated in <FIG> is now described.

After start of the sprayer <NUM>, step <NUM>, a first spraying operation is performed, step <NUM>, wherein spray liquid is supplied from the liquid tank <NUM> via the valve system <NUM> and the feed line <NUM> to the boom arm <NUM>, for application as a spray from the spray nozzles <NUM>. When the spraying operation is completed, step <NUM>, the valve system <NUM> shuts off the supply of spray liquid to the boom arm <NUM>. At this point, the ECU <NUM> is configured to start a cleaning operation of the spray applicator system <NUM>.

The ECU <NUM> commands the array of spray nozzles <NUM> to close, such that compressed air can be blown through the spray applicator system <NUM> from the compressed air supply <NUM>, step <NUM>. The ECU <NUM> controls the valve system <NUM> such that any residual spray liquid remaining in the spray applicator system <NUM> after the spray operation is blown into the auxiliary liquid tank <NUM>.

At this point, the ECU <NUM> commands the ozone supply <NUM> to inject ozone into the auxiliary tank <NUM>, step <NUM>, to cleanse the residual spray liquid of chemicals. As with the embodiment described in <FIG> and <FIG>, the ozone injection may be performed for a defined period of time, and/or until a monitored chemical concentration level of the liquid contained in the auxiliary tank <NUM> reaches a safe level, step <NUM>. At this point, the cleaned and sterilised liquid in the tank <NUM> may be drained, e.g. to ground, step <NUM>.

In order to monitor the chemical concentration level of the contained liquid, the system may be arranged to measuring the difference between input and output mass flows of ozone supplied to the system. When the supplied ozone mass flow input is equal to the output, accordingly this indicates that the chemical concentration is very low, as the level of reaction of the ozone with any remaining chemical is reduced.

In parallel with the ozone injection and liquid clean steps, <NUM>,<NUM>, the sprayer <NUM> can be configured to perform a second spray operation using the spray applicator system <NUM>, while a cleaning operation is being performed for the first spray operation. Accordingly, while the ECU <NUM> is commanding the ozone supply <NUM> to inject ozone to the auxiliary tank <NUM>, step <NUM>, the ECU <NUM> can also command that a spray liquid is supplied to the boom arm <NUM>, step <NUM>. The ECU <NUM> can then act to open the spray nozzles <NUM> of the boom <NUM>, in accordance with a second spray operation, step <NUM>.

It will be understood that the second spray operation may be performed using several alternative approaches. In one aspect, the sprayer may be reloaded with a "hot mix" of water and chemical already mixed at a local farm or facility. Alternatively, the sprayer may be loaded with water, while chemicals are added using an educator mounted on the sprayer, or mounted on a water supply truck. Further alternatively, the sprayer may be loaded with water and a direct chemical injection system can be used to inject chemicals into the water just prior to spraying, when the water is already in the boom plumbing. It will be further understood that the spray liquid used in the second spray operation may be supplied from the liquid tank <NUM>, or from a secondary liquid tank <NUM> which can be coupled with the valve system <NUM>. The second spray liquid may be a different liquid than that used in the first spray operation, or may be the same liquid, but mixed in a different concentration or used in combination with additional spray liquids.

When the spraying operation is completed, step <NUM>, the valve system <NUM> shuts off the supply of spray liquid to the boom arm <NUM>. At this point, the ECU <NUM> can be arranged to start a further cleaning operation of the spray applicator system <NUM>, step <NUM>, to clean any residual spray liquid remaining after the second spray operation <NUM>. Such a further cleaning operation may be performed through use of the auxiliary tank <NUM>, as described in steps <NUM>-<NUM>, and/or through use of ozone injection into a fluid recirculation mode, as described in steps <NUM>-<NUM> of <FIG>.

Claim 1:
A method of operating an agricultural sprayer, the agricultural sprayer (<NUM>) comprising a liquid tank (<NUM>) to hold a spray liquid and a spray applicator system (<NUM>) coupled to the liquid tank (<NUM>), the method comprising the step of supplying a spray liquid from the liquid tank (<NUM>) to the spray applicator system (<NUM>) to perform a spraying operation, characterised in that the method further comprises the step of, after the spraying operation is complete, supplying ozone to clean at least a portion of the agricultural sprayer (<NUM>).