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 limiting or promoting plant growth, e.g. through use of liquid growth regulators and fertiliser respectively. 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.

Agricultural crop sprayers typically comprise a product tank for holding a solution of plant protection product, and a product dispensing system for applying the solution to the field or crop. The product dispensing system is commonly provided by a series of nozzles spaced along a boom which itself extends transversely with respect to a forward direction of travel. A plumbing network is provided to fluidly connect the product tank with the nozzles and typically comprises hoses and controllable valves to direct the fluid as required.

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 procedures, to prevent contamination or injury to crops or to the environment in general.

It is known to provide sprayers with an on-board rinse tank which is separate to the product tank and is connected to the plumbing network. During a rinse process, which may be concurrent with a spraying operation, clean water is conveyed from the rinse tank through the plumbing network to the nozzles and/or the product tank. The dilute 'rinsings' are then dispensed onto the crop, onto a piece of land or into a biobed for example.

Such cleaning procedures often require the rinsing of the product tank and plumbing with a large volume of rinse water to ensure safe concentration levels. However, such excessive use of water can be relatively wasteful, as well as 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. Such a crop sprayer is disclosed in <CIT>.

In accordance with a first aspect of the invention there is provided an agricultural crop sprayer comprising a product tank for holding a solution of plant protection product, a product dispense system, a rinse tank for holding a rinse fluid, and a plumbing network which fluidly connects the product tank, the product dispense system and the rinse tank, wherein the sprayer further comprises a heat source configured to heat the rinse fluid.

In accordance with a second aspect of the invention there is provided a method of operating an agricultural crop sprayer, the crop sprayer comprising a product tank for holding a solution of plant protection product, a product dispense system, and a rinse tank for holding a rinse fluid, the method comprising the steps of:.

By utilising rinse water or fluid that is heated above an ambient temperature the sprayer is more effectively rinsed. Warm or hot water has an increased kinetic activity and a higher saturation point compared to cooler ambient water. As such heated water is more effective at removing chemical residues, especially sticky or powdery residues that are difficult to shift with cold water. Advantageously, the invention delivers more effective removal of chemical residues and offers the potential to reduce the volume of water required to deliver sufficient cleaning.

In a preferred embodiment a prime mover provides the heat source. The prime mover may be an internal combustion engine or an electric motor by way of example. It will be recognised that sprayers typically include an engine whether that be an engine of a self-propelled sprayer or an engine of a tractor towing a trailed sprayer. The prime mover may serve to deliver a driving torque to ground engaging wheels for propulsion of the sprayer.

Prime movers typically expel significant quantities of waste energy in the form of heat. Advantageously, this waste heat can be exploited to heat the rinse fluid. A heat exchange system may be configured to transfer waste heat from the prime mover to the rinse fluid wherein a first heat exchanger is arranged to extract waste heat from the prime mover.

Waste heat from the prime mover can be transferred to the rinse fluid using one of several different arrangements. In one embodiment of this aspect, the heat exchange system involves a closed fluid circuit which includes the heat exchanger associated with the prime mover and a second heat exchanger located inside the rinse tank. In this arrangement a closed cooling circuit of the prime mover is extended so as to transfer the waste heat to the rinse fluid indirectly. The second heat exchanger may, for example, comprise a coil immersed in the rinse fluid inside the rinse tank.

In another embodiment, waste heat is transferred directly from the prime mover to the rinse fluid. In this embodiment the heat exchange system comprises a fluid circuit which includes the first heat exchanger being fluidly connected to the rinse tank wherein the rinse fluid serves as a heat exchange medium which is passed through, or proximate to, the prime mover.

The heat exchange system may further comprise a thermostat to regulate the temperature of the rinse fluid.

In yet another embodiment a hydraulic system provides the heat source. The hydraulic system may include a hydraulic pump and one or more hydraulic consumers for powering various systems on the sprayer. In one example, a trailed sprayer comprises a hydraulic pump that is driven mechanically from a power takeoff shaft of a tractor attached to the sprayer. Waste heat generated by the hydraulic system may be collected and transferred to the rinse fluid by a heat exchange system which may include a closed fluid circuit.

In the case of scavenged waste heat serving as the heat source, whether that be from a prime mover or from a hydraulic system, a further advantage is a reduced dedicated cooling requirement and thus a cooling system of a reduced size. In other words, the extraction of the waste heat itself serves to cool the prime mover or hydraulic system.

In yet another embodiment a dedicated heat source is provided. For example the heat source may be a liquid fuel burner or an electrically-powered immersion heater.

In another preferred embodiment a further rinse tank is provided and serves as a cold rinse tank for holding rinse fluid at a cooler ambient temperature. In this arrangement there is provided a heated rinse tank and an ambient or cold rinse tank. It is recognised that heated rinsings may have a detrimental effect if applied to a crop. By providing a second rinse tank for cooler water, a sequenced rinsing process may be employed wherein a heated rinse step is followed by a cold rinse step. The rinsings may be combined before being dispensed.

A sprayer having both hot and cold rinse tanks offers several advantages. Firstly, the heated rinsings may be cooled before being dispensed to crops as explained above. Secondly, a smaller volume of heated rinse fluid may be required thus potentially allowing for the rinse fluid to be heated to higher temperatures with the same energy input.

Further advantages of the invention will be apparent from reading the following description of specific embodiments of the invention with reference to the appended drawings in which:.

The following detailed description illustrates the invention by way of example and not by way of limitation. This description will clearly enable one skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives and uses of the invention, including what we presently believe is the best mode of carrying out the invention. Additionally, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways.

Use of directional terms such as "front", "rear", "longitudinal" and "transverse" in the following description of specific embodiments is made in relation to the normal forward direction of travel of an agricultural crop sprayer having a longitudinal axis parallel to the direction of travel.

Various embodiments are illustrated and described. Like components that are common to multiple embodiments will share the same reference numerals for ease of understanding.

<FIG> shows an agricultural crop sprayer <NUM> used to apply crop protection products to agricultural crops in a field. Agricultural crop 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 sprayer <NUM>. An internal combustion 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 torque to propel the agricultural sprayer <NUM> and also to provide energy used to power the on-board spray systems which will be described below.

Although a self-propelled crop sprayer 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 product tank <NUM> used to store a liquid solution of plant protection product to be sprayed on the field. The solution can include chemicals or plant protection products (PPPs), such as but not limited to, herbicides, fungicides, insecticides, plant growth regulators, and/or fertilizers. Product tank <NUM> is mounted on chassis <NUM>, either in front of or behind cab <NUM>. The crop sprayer <NUM> can include more than product 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.

A sprayer system according to one aspect of the invention is illustrated in a schematic outline in <FIG> at <NUM>. The sprayer system <NUM> is suitable for implementation on sprayer <NUM>. System <NUM> further comprises a rinse tank <NUM> for holding a rinse fluid which can be used to rinse the product tank <NUM> and associated plumbing after or during a spraying operation.

At least one boom <NUM> on the sprayer <NUM> is used to distribute the fluid from the product tank <NUM> over a wide swath as the sprayer <NUM> is driven through the field. The boom <NUM> is mounted to the rear of the chassis <NUM> and extends transversely away the chassis <NUM>. The boom is provided as part of a product dispense system <NUM>, which further comprises an array of spray nozzles <NUM> arranged along the length of the boom <NUM>.

A plumbing network is provided which fluidly connects the product tank <NUM>, the product dispense system <NUM> and the rinse tank <NUM>. The plumbing network will be understood to comprise any suitable valves, tubing or piping arranged for fluid communication of these components.

In more detail, the plumbing network comprises suction portion connected to a suction side of fluid pump <NUM> and a pressurised portion connected to a pressure side of pump <NUM>. Pump <NUM> is driven in this embodiment by a drive connection <NUM> which derives torque from engine <NUM>.

The suction portion of the plumbing network includes an input valve or manifold <NUM> which selectively connects a respective outlet of the product tank <NUM> and the rinse tank <NUM> to a suction side of the pump <NUM>. A boom recirculation line <NUM> is also connected to the input manifold <NUM>. The pressurised portion of the plumbing network comprises a distribution valve <NUM> which selectively directs pressurised fluid from the pressure side of pump <NUM> to one of a boom supply line <NUM> and a tank rinse line <NUM>. The manifolds <NUM>,<NUM> can comprise any suitable configuration of valve elements, e.g. a single multiport valve element, or an array of individual elements.

The sprayer <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 distribution valve <NUM>, the input valve <NUM>, the pump <NUM>, the 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.

During a spraying mode of operation the pump <NUM> draws PPP solution from product tank <NUM> via input manifold <NUM> and delivers the solution at pressure to the product dispense system <NUM> via distribution valve <NUM> and boom supply line <NUM>. The pressurised solution is dispensed to the field by nozzles <NUM>.

Optionally, when the rate of application is low, the PPP solution may be recirculated via boom recirculation line <NUM>.

During a rinse mode of operation the pump <NUM> draws rinse fluid from rinse tank <NUM> via input manifold <NUM> and delivers the rinse fluid at pressure to a set of tank rinse nozzles <NUM> via tank rinse line <NUM>. The tank rinse nozzles <NUM> are mounted inside the product tank <NUM> and are positioned so as to direct a cleaning jet of fluid at the internal surfaces of the product tank <NUM>.

Optionally, the rinse mode of operation may involve the distribution manifold <NUM> directing some or all of the pressurised rinse fluid through the boom supply line <NUM> and the boom recirculation line <NUM> so as to rinse chemical residue therefrom.

In accordance with an aspect of the invention, the rinse fluid is heated by waste heat from the engine <NUM>. A heat exchange system <NUM> comprises a closed fluid circuit having a heat exchanger <NUM> immersed in the rinse fluid inside the rinse tank <NUM>. The heat exchanger <NUM> is fluidly connected in the fluid circuit to a further heat exchanger that is associated or integrated with engine <NUM>. The fluid circuit includes a heated line <NUM> and a cooled line 40C.

The heat exchange system <NUM> may operate during a spraying mode of operation so as to scavenge and exploit the waste heat from engine <NUM> to heat the rinse fluid. By using heated rinse fluid the cleaning effectiveness during the rinse mode is significantly improved.

A thermostat <NUM> is provided in the heat exchange system so as to regulate the temperature of the rinse fluid. For example, the thermostat <NUM> may be adapted to regulate the temperature around <NUM>-<NUM>. Although a connection is not shown, the thermostat <NUM> may be in communication with the ECU <NUM>, wherein the ECU <NUM> may be configured to control the temperature of the rinse fluid dependent upon operating conditions or upon operator commands.

With reference to <FIG> a second embodiment of a spray system <NUM> utilises a different heat exchange system to that described above in relation to heating the rinse fluid. In this embodiment waste heat from the engine <NUM> is recovered and transferred directly to the rinse fluid.

The heat exchange system <NUM> uses the rinse fluid itself as a heat exchange medium by transporting the rinse fluid from the rinse tank <NUM> to a heat exchanger associated with engine <NUM> and returning the heated fluid to the rinse tank <NUM>. The fluid circuit comprises a heated line <NUM> and a cooled line 52C. The fluid may be circulated by a water pump (not shown) drivingly connected to the engine <NUM>.

With reference to <FIG>, a third embodiment of a spray system <NUM> utilises waste heat from parts of an on-board hydraulic system, in this case the pump <NUM>. It should be understood that engine <NUM> and the input manifold control line has been omitted from <FIG> only for reasons of clarity. In this embodiment waste heat from the pump <NUM> is recovered and transferred directly to the rinse fluid.

A heat exchange system <NUM> comprises a heat exchanger <NUM> that is mounted proximate to, or integrated with, the pump <NUM>. The heat exchanger <NUM> is connected in a fluid circuit having a heated line <NUM> and a cooled line 62C. The cooled line 62C conveys rinse fluid from rinse tank <NUM> to the heat exchanger <NUM>, whereas the heated line conveys heated rinse fluid from the heat exchanger <NUM> to the rinse tank <NUM>. A pump (not shown) may be provided in the fluid circuit to force movement of the rinse fluid.

In the embodiment illustrated by <FIG> the rinse fluid is heated directly by the heat exchange system <NUM>. However, it is envisaged that an independent closed fluid circuit could alternatively be provided together with a heat exchanger in the rinse tank <NUM> to heat the rinse fluid indirectly.

Although waste heat from the pump <NUM> of the sprayer system <NUM> is extracted in this embodiment, it is envisaged that waste heat from other components of a hydraulic system could instead be scavenged whilst remaining in the scope of the invention.

In a fourth embodiment (<FIG>) a spray system <NUM> comprises a heated rinse tank <NUM> and a cold rinse tank <NUM>. The rinse fluid in the heated rinse tank <NUM> is heated using a heat exchange system <NUM> which is the same as that used by the first embodiment illustrated in <FIG>. However, it should be appreciated that the manner in which the rinse fluid is heated is not critical to this embodiment.

The cold rinse tank <NUM> serves to hold a volume of rinse fluid at ambient temperature (which is generally cooler than the heated rinse fluid) as is common in known sprayers. The cold water rinse tank <NUM> has an outlet connected to the input manifold <NUM> for selective delivery of cold rinse fluid through the pump <NUM>.

It is recognised that, depending on the temperature, heated rinse fluid may cause damage to crops and discharge of the dilute rinsings should be avoided in some situations. The cold rinse fluid from the cold rinse tank <NUM> can be used in a second stage of rinsing to cool the rinse fluid before being discharged.

An example method of operation of the spray system <NUM> of <FIG> is illustrated in <FIG>. In a first step <NUM> the rinse fluid in heated rinse tank <NUM> is heated above ambient temperature by transfer of waste heat from the engine <NUM> as explained above in relation to <FIG>. For example, the heated rinse fluid may be heated in excess of <NUM>.

In a second step <NUM> a rinse routine is initiated by a user command to the ECU <NUM>. In response the ECU <NUM> controls input manifold <NUM> (third step <NUM>) so as to connect the heated rinse tank <NUM> to the pump <NUM>. Also, the ECI <NUM> controls distribution manifold <NUM> so as to connect the pressure side of pump <NUM> to one or both of the boom supply line <NUM> and the tank rinse line <NUM>. As part of this rinse process the rinsings may be recirculated via the boom recirculation line <NUM> and/or the outlet of product tank <NUM>.

In a fourth step <NUM> the ECU <NUM> controls input manifold <NUM> so as to connect the cold rinse tank <NUM> to the pump <NUM>. In doing so this directs the cold (or ambient) rinse fluid in cold water rinse tank <NUM> through the plumbing network and to the tank rinse nozzles <NUM>.

In a fifth step <NUM> the rinsings are dispensed typically via the nozzles <NUM>.

Although the above-described embodiments have involved the scavenging of waste heat from prime movers or hydraulic systems it is envisaged that dedicated heating sources may be provided to heat the rinse fluid in the rinse tank <NUM>. For example, a diesel burner or an electrically-powered immersion heater could be provided in a not illustrated embodiment.

Although the focus of the above-described embodiments has been on a self-propelled crop sprayer, it is envisaged that aspects of the invention can be implemented on trailed sprayers. In one embodiment heat may be scavenged from an engine or exhaust of a tractor to which the sprayer is attached. In another embodiment, heat may be scavenged from a PTO-driven pump mounted to the chassis of a trailed sprayer.

In summary there is provided an agricultural crop sprayer which includes a product tank for holding a solution of plant protection product, a product dispense system and a rinse tank for holding a rinse fluid. A plumbing network fluidly connects the product tank, the product dispense system and the rinse tank. A heat source is provided to heat the rinse fluid. The heat source may be a prime mover or a hydraulic pump wherein waste heat is scavenged therefrom.

Claim 1:
An agricultural crop sprayer (<NUM>) comprising a product tank (<NUM>) for holding a solution of plant protection product, a product dispense system (<NUM>), a rinse tank (<NUM>) for holding a rinse fluid, and a plumbing network which fluidly connects the product tank (<NUM>), the product dispense system (<NUM>) and the rinse tank (<NUM>), characterised in that the sprayer further comprises a heat source (<NUM>; <NUM>) configured to heat the rinse fluid.