WO2018203067A1

WO2018203067A1 - Spray apparatus

Info

Publication number: WO2018203067A1
Application number: PCT/GB2018/051185
Authority: WO
Inventors: Andrew Kneen
Original assignee: HOUSEHAM SPRAYERS Ltd
Current assignee: HOUSEHAM SPRAYERS Ltd
Priority date: 2017-05-05
Filing date: 2018-05-03
Publication date: 2018-11-08
Anticipated expiration: 2019-11-05
Also published as: GB201707221D0

Abstract

The present invention provides an agricultural sprayer comprising: a tank for holding a liquid; a plurality of nozzles arranged along a spray boom and fluidly connected to the tank; a pump for transferring the liquid from the tank to the nozzles; a control valve for controlling the pressure of the liquid being transferred from the tank to the nozzles by the pump; means for determining a baseline parameter of the control valve; and a controller for controlling the parameter of the control valve dynamically relative to the baseline in response to change of one or more variables.

Description

SPRAY APPARATUS

Field The present invention relates to spray apparatus as applied to an agricultural sprayer.

Background

Agricultural sprayers can either be self-propelled such as described in GB20120018741 or towed by a separately powered vehicle such as a tractor. In both cases, the main components of an agricultural sprayer are a tank for holding a quantity of liquid, an arrangement of spray nozzles on a spray boom and a pump for delivering the content of the tank to the spray nozzles under pressure. The rate of application of the liquid is set by a controller in terms of litre per hectare volume. The set value is measured as an average over a hectare and is determined by a combination of the forward speed of the sprayer and the pressure set by the application volume. As the forward speed of the sprayer is increased, the pressure of the liquid is also increased accordingly. As the forward speed of the sprayer is reduced, the pressure of the liquid is adjusted accordingly. A control valve is used to control the input pressure of the liquid in response to variations in the forward speed of the sprayer.

It is important to ensure that the liquid is evenly applied to the field to be sprayed. If the litre per hectare volume is set too low it is likely that weeds will grow or crops damaged by pests. If the litre per hectare volume is set too high there is a risk of weeds or pests becoming resistant to commonly used agricultural chemicals over time. Measuring the application of the liquid as an average litre per hectare is effective when a sprayer is travelling at a constant forward speed but less so when turning at the end of a field or when the sprayer slows down to negate an obstacle.

When the forward speed of the sprayer changes this variation is communicated to the controller and the regulation valve is controlled accordingly to change the pressure of the liquid being supplied to the nozzles. This process is entirely reactive and there is a delay between variation of the forward speed of the sprayer and adjustment of the liquid pressure. For example, as the sprayer approaches the end of a field it will naturally slow down in order to turn through one-hundred-eighty degrees and start its next pass along the field. At the point of slowing down the liquid will be applied at xx litre per hectare. The delay in adjustment of the liquid pressure results in an area at the end of the field being sprayed with more liquid than is necessary. Conversely, when the sprayer increases its forward speed there is again a delay between the sprayer speeding up and the liquid pressure being adjusted resulting in an area of the field being sprayed with less liquid than is necessary. Part of the reason for delay in adjusting flow rate/pressure of the liquid is caused by the controller being unaware of the position of the control valve when an adjustment is required. When the controller instructs the control valve to adjust the input pressure of the liquid it has to rely on the pressure/flow readings received from a pressure and/or flow sensor positioned at or adjacent to the nozzles. To provide the desired flow rate/pressure, the control valve may have to cycle to several positions before the desired flow rate/pressure is observed by the pressure and/or flow sensor. Such cycling results in a hysteresis effect whereby for a period of time the flow rate/pressure of the liquid is either above or below the desired flow rate/pressure. This effect can be exacerbated when the forward speed of the sprayer changes quickly and frequently, for example on very rough terrain, and can lead to large variations in real time application rate. Furthermore, the controller has no means of knowing what the sprayer operator might request next whether that is a variation in the forward speed of the sprayer, turning on/off sections of the spray boom or turning the sprayer at the end of the field or to avoid an obstacle, for example. The present invention seeks to address the aforementioned problems.

Summary

An aspect of the invention provides an agricultural sprayer comprising: a tank for holding a liquid; a plurality of nozzles arranged along a spray boom and fluidly connected to the tank; a pump for transferring the liquid from the tank to the nozzles; a control valve for controlling the pressure of the liquid being transferred from the tank to the nozzles by the pump; means for determining a parameter of the control valve; and a controller for controlling the parameter of the control valve dynamically in response to a change of one or more variables.

Determining a parameter of the control valve enables the controller to identify how the control valve should be adjusted to account for a change in one or more variables. Accordingly, the control valve can be controlled dynamically and accurately to quickly adjust the pressure/flow rate of the liquid in response to a change in the one or more variables. Such a configuration minimises variation of spray application if, for example, the sprayer slows down at the end of a field to turn and then accelerates back up to operating speed. As the sprayer slows, turns and accelerates, the controller adjusts the control valve accordingly based on its measured position to keep the pressure/flow rate of the liquid consistent with the selected litres per hectare application rate.

Furthermore, if a variable changes often so as to require regular adjustments of the control valve, the present invention significantly reduces the hysteresis effect that can be exhibited by the prior art by quickly adjusting the position of the control valve upon, or in some cases before, changes of one or more variables.

The parameter of the control valve may be the position of the control valve.

The means for determining the position of the control valve may be a potentiometer.

Use of a potentiometer provides a reliable and repeatable output dependent on the position of the control valve at a known litre per hectare application rate and/or pressure/flow rate reading from a pressure/flow sensor. The position of the control valve can thus be accurately determined based on the potentiometer output for given settings and sensor readings.

The potentiometer may provide an output associated with the position of the control valve and the output is stored in a controller memory.

Storage of the potentiometer output in a controller memory enables the starting position of the control valve to be automatically set following selection of a desired mode, i.e. spray, fill, chemical induction, tank wash and rinse or boom flush, and spray mode is adjusted in advance of a predicted change in one or more variables, i.e. the sprayer GPS position or forward speed. Such predictive functionality enables the application rate to remain consistent when boom sections are automatically switched on/off upon determination that certain sections of field have already been sprayed or upon approach to sections that have not yet been sprayed. Furthermore, the operator is not required to manually set the required pressure for each of the different modes, although manual adjustment is possible if necessary.

The sprayer may comprise a GPS module for determining the real time position of the agricultural sprayer.

Determination of the real time position of the sprayer enables the controller to regulate the control valve in real time in response to a predicted action, i.e. slowing of the sprayer as it approaches the field boundary or the gradient of the field increases. Accordingly, the pressure of the liquid can be adjusted to maintain a consistent application rate regardless of the forward speed of the sprayer. Furthermore, sections of the sprayer boom can be automatically turned on/off as necessary in response to GPS data processed by the controller and the application rate adjusted accordingly.

The one or more variables may include, but are not limited to: forward speed of the agricultural sprayer GPS positioning, elevation change and physical obstacles.

The sprayer may comprise one or more pressure and/or flow sensors.

The one or more variables may further include pressure and/or flow rate.

Another aspect of the invention provides a method of operating an agricultural sprayer, the method comprising the steps of: i) providing an agricultural sprayer comprising a tank for holding liquid, a plurality of nozzles arranged along a spray boom and fluidly connected to the tank, a pump for transferring the liquid from the tank to the nozzles, a control valve for controlling the pressure of the liquid being transferred from the tank to the nozzles by the pump and a controller for determining and controlling a position of the control valve; ii) setting a liquid application rate; ii) setting a starting position of the control valve associated with the liquid application rate; iii) monitoring the position of the control valve; and iv) adjusting the position of the control valve in response to identification of one or more variables.

By setting the position of the control valve at the outset of an operation, the controller can establish a base line from which it can adjust the position of the control valve in response to identification of one or more variables. The controller always knows the position of the control valve and is able to adjust the control valve continuously to maintain the desired liquid pressure/flow rate or application rate and maintain a continuous application rate regardless of the forward speed of the sprayer.

Another aspect of the invention provides a method of operating an agricultural sprayer, the method comprising the steps of: i) identifying a baseline measurement for one or more parameters of the sprayer; ii) monitoring the one or more parameters of the sprayer; iii) identifying changes in one or more environmental variables; iv) adjusting the one or more parameters of the sprayer in advance of changes in the one or more environmental variables;

Another aspect of the invention provides an agricultural sprayer comprising: a tank for holding a liquid; a plurality of nozzles arranged along a spray boom and fluidly connected to the tank; a pump for transferring the liquid from the tank to the nozzles; a control valve for controlling the pressure of the liquid being transferred from the tank to the nozzles by the pump; a potentiometer for determining a position of the control valve; and a controller for controlling the position of the control valve dynamically in response to change of one or more variables.

Another aspect of the invention provides a control valve for an agricultural sprayer comprising a valve body and a valve mechanism moveable between at least a first and second position relative to the valve body, and a potentiometer operable to provide an output associated with the position of the valve mechanism.

Another aspect of the invention provides a control system for an agricultural sprayer comprising a control valve operable to move between at least a first and second position, a potentiometer operable to provide an output associated with the position of the valve and a controller operable to receive the output from the potentiometer and compare said output with a stored value for a given set of sprayer parameters, wherein the controller is further operable to adjust the position of the control valve to match the output of the potentiometer with the stored value for the given set of sprayer parameters. Figures

The invention will now be described by way of reference to the following figure: Figure 1 illustrates a schematic of spray apparatus according to the present invention.

Description

Referring to Figure 1 , the basic components of an agricultural sprayer 10 are a tank 12 for holding a liquid, a plurality of nozzles 14 arranged along a spray boom 30, a pump 16 for transferring the liquid from the tank to the nozzles 14 and a control valve 18 for controlling the flow of liquid from the tank 12 to the nozzles 14. The configuration of the tank 12, nozzles 14 and pump 16 will not be discussed further due to being commonplace. Each of the above components is mounted onto a chassis, which, in the case of a self- propelled sprayer 10, defines a power generation unit and a wheelbase sized for a particular application. Furthermore, a cab is positioned at the front of the sprayer 10 within which power, steering and operational controls are situated.

The pump 16 and control valve 18 are regulated by a controller 20. The controller 20 is operable to set a litre per hectare application rate and control the transfer of the liquid from the tank 12 to the nozzles 14 accordingly. The position of the control valve 18 is adjusted by the controller 20 in response to changes in forward speed of the sprayer

10 such that the higher the forward speed of the sprayer 10 the greater the pressure of the liquid and conversely, the lower the speed of the sprayer 10, the lower the pressure of the liquid. Overall, the volume of liquid sprayed from the nozzles 14 will substantially match the litre per hectare application rate set by the controller 20. The controller is itself controlled by a master ECU 26.

The position of the control valve 18, i.e. its angular orientation, is measured by a potentiometer 22. The potentiometer 22 provides an output that is associated with the position of the control valve 18 for a given litre per hectare application rate and associated flow or pressure sensor reading. The controller 20 stores the potentiometer

22 output in a non-volatile memory for retrieval next time a particular application rate is entered into the controller 20 by an operator.

In use, as the forward speed of the sprayer 10 increases/decreases the controller 20 identifies such a variation in forward speed and retrieves potentiometer 22 outputs from the memory that are associated with the particular litre per hectare application rate at a given forward speed and flow or pressure reading. Such real time monitoring and control enables the control valve 18 to be regulated in a manner such that the litre per hectare application rate remains consistent during the spraying operation and reduces the amount of variation in spray application in response to environmental and operational variables.

The controller 20 is also in communication with a GPS unit 24 that determines the position of the sprayer 10 to within fifty centimetres. The controller 20 can determine from the GPS information where the sprayer 10 is located in relation to a field boundary. Upon detecting that the sprayer 10 is approaching the field boundary or other obstacle, the flow rate or pressure of the liquid can be reduced and/or certain sections of the spray boom 30 can be turned off. By identifying the real time position of the control valve 18 through the potentiometer 22 output and adjusting the position of the control valve 18 such that the potentiometer 22 output achieves a stored value associated with a desired control valve 18 position, the controller 20 can quickly and accurately adjust the flow of liquid avoiding a hysteresis effect. The GPS unit 24 is itself controlled by the master ECU 26 The controller 20 is pre-programmed to turn sections of the spray boom 30 on/off during the spraying operation depending on the real-time position of the sprayer 10 and the spray volume required at its current position. As the sprayer approaches the field boundary, for example, the controller identifies that one or more sections of the spray boom 30 are not required as the sprayer 10 turns through one-hundred-eighty degrees. Accordingly, the controller 20 turns off the sections of the spray boom 30 that are not required. As the sprayer 10 completes its turn at the field boundary, the controller 20 recognises that additional sections of the spray boom 30 are again required to spray the field across the entire span of the spray boom 30 and turns the required sections back on.

The controller 20 can identify environmental variables such as position of the sprayer 10 relative to the boundaries of the field, changes in elevation, gradients, crop height, ground firmness and pre-programmed obstacles.

Furthermore, the controller 20 identifies when the sprayer 20 is overlapping sections of field that have already been sprayed and automatically turns off sections of the spray boom 30 to avoid the relevant area being sprayed again. Similarly, when the controller 20 identifies that the sprayer 10 is approaching a section of field that has not been sprayed it turns the relevant section of the spray boom 30 back on.

As the sprayer 10 approaches a section of field where sections of the spray boom 30 are to be turned on/off, the controller 20 processes the real time position of the sprayer as received from the GPS unit 24 and retrieves a stored potentiometer 22 output from memory where the stored potentiometer 22 output is associated with the desired position of the control valve 18. The controller 20 causes the control valve 18 to move to the control valve 18 position that re-produces the stores potentiometer 22 output thus adjusting the pressure/flow rate of the liquid as necessary to account for sections of the spray boom 30 being turned on/off.

The controller 20 is operable to select various different modes of operation including: spray, fill, chemical induction, tank wash and rinse and boom 30 flush. Each mode of operation has a pre-defined starting pressure, for example the starting pressure for spray mode may be greater than for fill mode although an operator can adjust the pressure. The controller stores a potentiometer 22 output associated with the starting position of the control valve 18. The starting position of the control valve 18 determines the starting pressure for each mode and acts as a base line for the controller 20 to control the control valve 18 in response to change of one or more variables. A multi- way valve 28 is used to direct liquid to/from the tank to one or more of the nozzles 14, an outlet, a chemical induction tank or a cleaning tank, for example.

The above description describes an embodiment of the invention and is not intended to limit the claims in any way.

Claims

1. An agricultural sprayer comprising:

a tank for holding a liquid;

a plurality of nozzles arranged along a spray boom and fluidly connected to the tank; a pump for transferring the liquid from the tank to the nozzles;

a control valve for controlling the pressure of the liquid being transferred from the tank to the nozzles by the pump;

means for determining a baseline parameter of the control valve; and

a controller for controlling the parameter of the control valve dynamically relative to the baseline in response to change of one or more variables.

2. An agricultural sprayer according to claim 1 , wherein the parameter of the control valve is a position of the control valve.

3. An agricultural sprayer according to claim 2, wherein the means for determining the position of the control valve comprises a potentiometer.

4. An agricultural sprayer according to claim 3, wherein the potentiometer provides an output associated with the position of the control valve and the output is stored in a controller memory.

5. An agricultural sprayer according to any of claims 1 to 4 further comprising a GPS module for determining the real time position of the agricultural sprayer.

6. An agricultural sprayer according to claim 5, wherein the one or more variables include: forward speed of the agricultural sprayer GPS positioning, elevation change and physical obstacles.

7. An agricultural sprayer according to any preceding claim further comprising one or more pressure and/or flow sensors.

8. An agricultural sprayer according to claim 7, wherein the one or more variables further include pressure or flow rate.

9. A method of operating an agricultural sprayer, the method comprising the steps of: providing an agricultural sprayer comprising a tank for holding liquid, a plurality of nozzles arranged along a spray boom and fluidly connected to the tank, a pump for transferring the liquid from the tank to the nozzles, a control valve for controlling the pressure of the liquid being transferred from the tank to the nozzles by the pump and a controller for determining and controlling a position of the control valve;

setting a liquid application rate;

setting a starting position of the control valve associated with the liquid application rate;

monitoring the position of the control valve; and

adjusting the position of the control valve in response to change of one or more variables.

10. A method according to claim 9, wherein the one or more variables include: forward speed of the agricultural sprayer GPS positioning, elevation change and physical obstacles.

11. A method according to claim 9 or claim 10, wherein the position of the control valve is monitored indirectly through the output from a potentiometer directly correlated to the positon of the control valve and communicated to the controller, wherein the potentiometer output relative to an associated control valve position is stored in a controller memory.

12. A method according to claim 1 1 comprising the further method step of comparing the potentiometer output of the control valve in real time to the stored potentiometer output and adjusting the position of the control valve accordingly to match the real time potentiometer output with the stored potentiometer output.

13. A method of operating an agricultural sprayer, the method comprising the steps of: i) identifying a baseline measurement for one or more parameters of the sprayer; ii) monitoring the one or more parameters of the sprayer;

iii) identifying changes in one or more environmental variables;

iv) adjusting the one or more parameters of the sprayer in advance of changes in the one or more environmental variables;

14. A method according to claim 13, wherein the one or more parameters of the sprayer include at least a position of a control valve operable to control pressure/flow rate of liquid output from the sprayer.

15. A method according to claim 13 or claim 14, wherein the one or more variables include: forward speed of the agricultural sprayer GPS positioning, elevation change and physical obstacles.

16. An agricultural sprayer comprising:

a tank for holding a liquid;

a potentiometer for determining a position of the control valve; and

a controller for controlling the position of the control valve dynamically in response to change of one or more variables.

17. A control valve for an agricultural sprayer comprising a valve body and a valve mechanism moveable between at least a first and second position relative to the valve body, and a potentiometer operable to provide an output associated with the position of the valve mechanism.

18. A control system for an agricultural sprayer comprising a control valve operable to move between at least a first and second position, a potentiometer operable to provide an output associated with the position of the valve and a controller operable to receive the output from the potentiometer and compare said output with a stored value for a given set of sprayer parameters, wherein the controller is further operable to adjust the position of the control valve to match the output of the potentiometer with the stored value for the given set of sprayer parameters.