AU2021261952A1 - Spraying system for an agricultural machine comprising a regulation valve - Google Patents

Abstract

The invention relates to a spraying system (10) for an agricultural machine, comprises a spray ramp (11) and a liquid circuit (12) itself comprising: - a pump (13) comprising an inlet (16) and an outlet (17), - discharge paths (14a-14g) each connected, upstream, to the pump outlet through 5 a discharge valve (18a-18g) opening or closing said discharge paths, - a regulation valve (15) connected, upstream, to the pump outlet and, downstream, to the pump inlet and designed to selectively regulate, as a function of said open discharge path(s), a liquid flow rate or pressure in the open discharge path(s) to a regulation flow rate or a first regulation pressure. 10 Figure for the abstract: Figure 1

Description

-' SPRAYING SYSTEM FOR AN AGRICULTURAL MACHINE COMPRISING A REGULATION VALVE DESCRIPTION TECHNICAL FIELD

The invention relates to a spraying system for an agricultural machine, as

well as a method for piloting such a spraying system.

STATE OF PRIOR ART

It is known that there are spraying systems for an agricultural machine

comprising a spray ramp and a liquid circuit comprising a pump and, downstream of said pump, discharge paths. Each of the discharge paths is additionally connected to the pump

by means of a discharge valve designed to open and close said discharge path. At least one of the discharge paths performs, for example, an agricultural

spraying function of the spraying system: for this, it comprises spray nozzles mounted to the spray ramp and provided for spraying liquid, especially treatment liquid, onto plants of

a field to be treated. This discharge path further comprises a regulation valve mounted as

a bypass to the spray nozzles and provided to regulate a flow rate of liquid supplied to the spray nozzles, especially by returning all or part of the liquid circulating in this discharge

path to a tank which supplies the pump with liquid, especially treatment liquid. Other functions of the spraying system are fulfilled by the other discharge

paths, especially by means of hydraulic devices. However, the operation of these hydraulic devices is often sensitive to overpressure, so that a valve common to these other discharge

paths is generally provided. This valve communicates, upstream, with each of the other discharge paths, in parallel with their hydraulic devices, and, downstream, with the tank.

This valve is further dimensioned to open when a liquid pressure in these other discharge channels is higher than a predefined maximum pressure.

However, the implementation of this valve is problematic for several

reasons.

Firstly, this valve behaves differently depending on the liquid flow rate downstream of the pump, which especially involves different dimensioning of the valve

depending on the pump chosen for the spraying system, but also providing for dimensioning of the valve adapted to all pump speeds during operation of the spraying

system. This makes valve dimensioning both restrictive and delicate. Secondly, if this valve opens as soon as the liquid pressure in the other

discharge paths reaches the maximum pressure, there is often a delay in closing the valve,

when the liquid pressure in the other discharge paths falls below the maximum pressure again. This creates pressure drops in the liquid circuit that impede the operation of the

spraying system. In addition, since this valve is common to the other discharge paths,

setting the maximum pressure is necessarily a compromise between requirements of the different hydraulic components, so that the hydraulic components cannot operate

optimally. This can have negative consequences on the operation of the spraying system. This valve can also be responsible for water hammer in the fluid circuit, leading to significant damage to the fluid circuit.

Finally, the use of this valve is necessarily related to a loss of compactness of the liquid circuit and creates "dead" or "residual" volumes in the liquid circuit. This

results in an increase in the amount of waste and a greater loss of liquid, especially treatment liquid, when operating the spraying system. This is undesirable from both an

environmental and economic standpoint for a farmer operating the spraying system.

DISCLOSURE OF THE INVENTION

The purpose of the present invention is to overcome one or more of the drawbacks mentioned above.

To this end, one object of the invention is a spraying system for an agricultural machine, comprising a spray ramp and a liquid circuit itself comprising: - a pump comprising an inlet and an outlet, the pump being designed to suck liquid

through the inlet and to discharge the liquid sucked through the outlet,

- discharge paths each connected, upstream, to the outlet of the pump through a discharge valve designed to open and to close said discharge path, at least one of

the discharge paths, called a main discharge path, comprising spray nozzles mounted to the spray ramp and designed to spray liquid onto plants of a field to be

treated, the other discharge path(s), called secondary discharge paths, being devoid of spray nozzles mounted to the spray ramp,

- a regulation valve connected, upstream, to the pump outlet and, downstream, to

the pump inlet, the regulation valve being further designed to selectively regulate, as a function of said open discharge path(s), a liquid flow rate in the open discharge

path(s) to a predetermined regulation flow rate, or a liquid pressure in the open discharge path(s) to a first predetermined regulating pressure.

According to alternative embodiments that may be taken together or separately: - the spraying system further comprises a control unit designed to command the

regulation valve to flow-regulate the open discharge path(s), when at least one of

the open discharge path(s) is predetermined as being to be flow-regulated, and to

pressure-regulate the open discharge path(s), when none of the open discharge path is predetermined as being to be flow-regulated; - the one or more main discharge paths are predetermined as being to be flow

regulated and the one or more secondary discharge paths are predetermined as

being to be pressure-regulated; - the regulation valve comprises a valve body defining an air chamber and a liquid

chamber separated from each other by a slide valve comprising a seat arranged in the liquid chamber, the liquid chamber comprises an inlet port communicating with

the pump outlet and an outlet port communicating with the pump inlet, the slide valve further being capable of moving in the valve body, as a function of a difference

between an air pressure in the air chamber and a pressure of the liquid circulating

in the liquid chamber, from the inlet port to the outlet port, so as to move the seat toward or away from the outlet port;

- the spraying system comprises a control unit designed to: o determine one or more closed discharge path(s) to open and one or more open discharge path(s) to close; o decrease air pressure in the air chamber of the regulation valve; o open the closed discharge path(s) to open and close the open discharge path(s) to close, simultaneously or successively, in either order; o increase air pressure in the air chamber of the regulation valve until selectively, as a function of the discharge path(s) thus opened: • the flow rate of liquid circulating in the open discharge path(s) reaches the regulation flow rate, or • the pressure of liquid circulating in the open discharge conduit(s)

14a-14g reaches the first regulation pressure; - the control unit is designed to decrease air pressure in the air chamber of the

regulation valve for a predetermined target period or until a predetermined target pressure is reached.

Another object of the invention is a method for piloting a spraying system

for an agricultural machine as previously described, comprising a step of selectively regulating, by means of the regulation valve, as a function of the open discharge path(s),

the flow rate of liquid circulating in the open discharge path(s) to the regulation flow rate, or the pressure of liquid circulating in the open discharge path(s) to the first regulation

pressure. According to alternative embodiments which may be taken together or

separately: - during the selective regulation step, the flow rate of liquid circulating in the open

discharge path(s) is regulated to the regulation flow rate, when the or at least one of the open discharge path(s) is predetermined as being to be flow-regulated, and

the pressure of liquid circulating in the open discharge path(s) is regulated to the

first regulation pressure, when none of the open discharge path(s) is predetermined as being to be flow-regulated;

- the method comprises, prior to the selective regulation step: o a step of determining closed discharge path(s) to open and open discharge path(s) to close; o a step of decreasing air pressure in the air chamber of the regulation valve; o a step of opening the closed discharge path(s) to open and closing the open discharge path(s) to close, simultaneously or successively, in either order; o a step of increasing air pressure in the air chamber of the regulation valve until, selectively, as a function of the discharge path(s) thus opened, the flow rate of liquid circulating in the open discharge path(s) reaches the regulation flow rate, or the pressure of liquid circulating in the open discharge path(s) reaches the first regulation pressure; - during the decrease step, the air pressure in the air chamber of the regulation valve is decreased for a predetermined target period or until a predetermined target pressure is reached.

BRIEF DESCRIPTION OF THE DRAWINGS

Further aspects, purposes, advantages and characteristics of the

invention will become more apparent from the following detailed description of preferred

embodiments thereof, given by way of non-limiting example, and made with reference to the appended drawings in which: - Figure 1 is a schematic view of a spraying system for an agricultural machine,

according to one embodiment of the invention; - Figure 2 is a detail view of a regulation valve of the spraying system for an

agricultural machine; - Figure 3 is a flow chart of a method for piloting the spraying system illustrated in

Figure 1.

DETAILED DESCRIPTION

Figure 1 shows a spraying system 10 for an agricultural machine,

especially for spraying a treatment liquid in a field of plants to be treated, for example field

crops, such as cereal crops, according to one embodiment of the invention.

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The spraying system 10 is in contact with a ground, especially of the field of plants to be treated, for example by means of wheels (not represented) allowing its

movement. The spraying system 10 is, for example, for being towed by the

agricultural machine, such as a tractor. As an alternative (not represented), the spraying system 10 is for being carried by the agricultural machine. Still as an alternative (not

represented), the spraying system 10 is self-propelled and thus forms the agricultural

machine. An orthogonal reference frame is adopted, in a non-limiting way,

comprising a longitudinal direction frontwardly in the direction of travel of the agricultural machine, a transverse direction leftwardly and a vertical direction upwardly. The

longitudinal and transverse directions are horizontal, overall parallel to the ground. The spraying system 10 comprises a spray ramp 11 extending, for

example, along a horizontal, especially overall transverse, main extension direction, and a liquid circuit 12.

The liquid circuit 12 comprises a pump 13, discharge paths 14a-14g, as

well as a regulation valve 15. The pump 13 comprises an inlet 16 through which the pump 13 sucks a

liquid and an outlet 17 through which the pump 13 discharges the liquid sucked through the inlet 16.

Alternatively, the liquid circuit 12 may comprise, in addition to the pump 13, another pump. The pump 13 and the other pump are connected in parallel with each

other. In the following, the terms "upstream" and "downstream" reflect the

liquid circulation direction in the liquid circuit 12, which is imposed by the pump 13. The discharge paths 14a-14g are each connected, upstream, to the outlet

17 of the pump 13 through a discharge valve 18a-18g designed to open and close said

discharge path 14a-14g. A different discharge valve 18a-18g connects for example each discharge

path 14a-14g to the outlet 17 of the pump 13. One or more discharge valves 18a-18g common to multiple discharge paths 14a-14g may also connect said discharge paths 14a 14g to the outlet 17 of the pump 13.

Each of the discharge paths 14a-14g may perform a separate function of the spraying system 10 This is for example the case of the spraying system 10 illustrated in

Figure 1. At least one 14a of the discharge paths 14a-14g, referred to as the main

one, comprises spray nozzles 19 mounted to the spray ramp 11 and designed to spray

liquid, especially treatment liquid aswill be explained in the following description, onto the plants of the field to be treated. The main discharge path(s) 14a thus provide an agricultural

spraying function of the agricultural spraying system 10. The other, so-called secondary, discharge path(s) 14b-14g is(are) devoid

of spray nozzles mounted to the spray ramp 11. Thus, the other discharge path(s) 14b-14g provide functions of the spraying system 10 other than the agricultural spraying function.

These other functions of the spraying system 10 will be detailed in the remainder of the description.

According to the invention, the regulation valve 15 is connected,

upstream, to the outlet 17 of the pump 13 and, downstream, to the inlet 16 of the pump 13. The regulation valve 15 is thus connected in parallel to the discharge paths 14a-14g and

forms a loop with the pump 13. The regulation valve 15 is further designed to selectively regulate, as a function of said open discharge path(s) 14a-14g, a liquid flow rate in the open

discharge path(s) 14a-14g to a predetermined regulation flow rate, or a liquid pressure in the open discharge path(s) 14a-14g to a first predetermined regulation pressure.

By virtue of the regulation valve 15, it is thus possible to opt for either flow or pressure regulation depending on which discharge path(s) 14a-14g are open, and

thus depending on which function of the spraying system 10 is activated. The most appropriate regulation per discharge path 14a-14g, and thus per function of the spraying

system 10, can thus be implemented.

For example, when the main discharge path(s) 14a is (are) open, with the agricultural spraying function activated, the regulation valve 15 can flow-regulate said main

discharge path(s) 14a, so as to command the amount of liquid discharged by the pump 13 that supplies the spray nozzles 19. Pressure regulation of the main discharge path(s) 14a may also be appropriate.

When the secondary discharge path(s) 14b-14g is/are open and the main discharge path(s) 14a is/are closed, with a function(s) other than the agricultural spraying

function activated, the regulation valve 15 may pressure-regulate said secondary discharge path(s) 14b-14g. Pressure regulation is, for example, more appropriate than flow regulation

when the secondary discharge paths 14b-14g comprise hydraulic members designed to

operate over a predetermined pressure range. Examples of such hydraulic members will be provided later in the description.

The regulation valve 15 further allows differentiated values of regulation flow rate and/or first regulation pressure depending on which discharge path(s) 14a-14g

are open, and thus depending on which function of the spraying system 10 is activated. In this manner, the value of the first regulation pressure can, for example, be adapted for

each secondary discharge path 14b-14g, depending on the predetermined pressure range(s) of the hydraulic member(s) of said secondary discharge path 14b-14g.

The regulation valve 15 also makes it possible to dispense with any

difficulty relating to its dimensioning as a function of the pump 13 and its speeds, as well as any compromise with regard to requirements of the various hydraulic members of the

secondary discharge paths 14b-14g. The regulation valve 15, which is common to all the discharge paths 14a-14g, that is, to both the main discharge path 14a and the secondary

discharge path 14b-14g, also allows for a gain in the compactness of the spraying system 10, thus limiting "dead" or "residual" volumes in the liquid circuit 12 and thus the quantity

of liquid, especially treatment liquid, that cannot be used. The liquid circuit 12 also comprises, for example, a main tank 20 for

holding treatment liquid. The main tank 20 is connected to the inlet 16 of the pump 13 by means

of a so-called main suction path 21a. The pump 13 can thus suck treatment liquid from the

main tank 20 to discharge it towards the open discharge path(s) 14a-14g, especially towards the main discharge path(s) 14a, so as to supplythe spray nozzles 19 with treatment

liquid to spray it onto the plants of the field to be treated. The spray nozzles 19 are thus designed to spray treatment liquid onto the plants of the field to be treated, when the main suction path 21a and the main discharge path(s) 14a are open.

The liquid circuit 12 may further comprise one or more so-called secondary suction paths 21b-21c, which are connected, downstream, to the inlet 16 of the

pump 13. When the liquid circuit 12 comprises a plurality of suction paths 21a-21c,

said suction paths 21a-21c are each, for example, connected, downstream, to the inlet 16

of the pump 13 through a suction valve 22a-22c designed to open and close access to the inlet 16 of the pump 13 from said suction path 21a-21c.

Forexample, a different suction valve 22a-22c connects each suction path 21a-21c to the inlet 16 of the pump 13. One or more suction valves 22a-22c common to

multiple suction paths 21a-21c may also connect said suction paths 21a-21c to the inlet 16 of the pump 13.

One 21b of the secondary suction paths 21b-21c comprises, for example, an inlet hydraulic connector 23 for reversible connection to a liquid source external to the

spraying system 10. In this manner, when said secondary suction path 21b is open, the

pump 13 sucks liquid external to the spraying system 10. One 21c of the secondary suction paths 21b-21c comprises, for example,

one or more rinse tanks 24 for holding clear water. In this manner, when said secondary suction path 21c is open, the pump 13 sucks clear water from the one or more rinse tanks

24 to rinse or clean the spraying system 10. The or each main discharge path 14a comprises, for example, a supply

conduit 50 connecting the outlet 17 of the pump 13 to the spray nozzles 19, so as to supply them with liquid, especially spray liquid. The or each main discharge path 14a may further

comprise a three-way valve 51, as well as a return conduit 52 connecting the spray nozzles 19 to the three-way valve 51. The three-way valve 51 is further designed to, in a first

position, return the liquid circulating in the return conduit 52 to the supply conduit 50, and

in a second position, send the liquid circulating in the return conduit 52 to the main tank 20. When the three-way valve 51 occupies the first position, the main discharge conduit

14a may be flow- or pressure-regulated. Each spray nozzle 19 may further be equipped

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with a valve (not shown) designed to release or block supply of liquid from the supply conduit 50 to said spray nozzle 19. Said valves, for example, block supply of liquid to the

spray nozzles 19, when the three-way valve 51 occupies the second position. When the three-way valve 51 occupies the second position, however, it is more appropriate to

pressure-regulate the main discharge path 14a. One 14b of the secondary discharge paths 14b-14g comprises, for

example, at least one stirring nozzle 25 arranged inside the main tank 20, especially at the

lower part of said main tank 20 to be immersed in the processing liquid contained therein. The stirring nozzle(s) 25 is (are) further designed to project the liquid discharged by the

pump 13 into the treatment liquid of the main tank 20, when said secondary discharge path 14b is open and the stirring nozzle(s) 25 is (are) immersed in the treatment liquid of the

main tank 20. In this manner, the stirring nozzle(s) 25 stir(s), mix(es) or otherwise agitate(s) the treatment liquid contained in the main tank 20. The liquid discharged by the pump 13

may be treatment liquid from the open main suction path 21a. The stirring nozzle(s) 25 thus ensure(s) metering of the treatment liquid sucked in to be sprayed, especially when it

is a slurry, that is a mixture of clear water and crop protection agent, which may settle. Said

secondary discharge path 14b thus provides a stirring function for the spraying system 10. The stirring nozzle(s) 25 form(s) an example of hydraulic members designed to operate

over a predetermined pressure range, so that a pressure regulation of said secondary discharge path 14b by the regulation valve 15 is more appropriate than a flow regulation.

The discharge valve 18b through which the secondary discharge path 14b performing the stirring function is connected to the outlet 17 of the pump 13 is for example

designed to regulate a liquid pressure in said secondary discharge path 14b to a predetermined second regulation pressure. In this way, when the main discharge path(s)

14a is (are) open and the regulation valve 15 flow-regulates, for example, the main discharge path(s) 14a, said discharge valve 18b can still pressure-regulate said open

secondary discharge path 14b. When the main discharge path(s) 14a is (are) open and the

regulation valve 15 pressure-regulates, for example, the main discharge path(s) 14a to the first regulation pressure, said discharge valve 18b may pressure-regulate said open

secondary discharge path 14b to the second regulation pressure, the value of which may be different from that of the first regulation pressure. This prevents the liquid, especially the treatment liquid, expelled from the stirring nozzle(s) 25 from reaching such a pressure that this liquid expulsion causes the treatment liquid in the main tank 20 to foam. Said discharge valve 18b is especially distinct from the other discharge valve(s) 18a, 18c-18g, which may be designed only to occupy an open position and a closed position. One 14c of the secondary discharge paths 14b-14g comprises, for example, at least one rinsing nozzle 26 arranged inside the main tank 20, especially at the top part of said main tank 20. The one or more rinsing nozzles 26 is (are) further designed to project the liquid discharged by the pump 13 into the main tank 20, especially onto walls of said main tank 20, when said secondary discharge path 14c is open. In this manner, the one or more rinsing nozzles 26 allow(s) the main tank 20 to be rinsed. The liquid discharged by the pump 13 may be clear water from the rinse tank(s) 24 of the corresponding open secondary suction path 21c. Said secondary discharge path 14c thus provides a rinsing function for the spraying system 10. The rinsing nozzle(s) 26 form an example of hydraulic members designed to operate over a predetermined pressure range, so that a pressure regulation of said secondary discharge path 14c by the regulation valve 15 is more appropriate than a flow regulation. One 14d of the secondary discharge paths 14b-14g comprises, for example, a Venturi effect device 27 through which said secondary discharge path 14d connects the outlet 17 of the pump 13 to the main tank 20. The liquid discharged by the pump 13 thus circulates through the Venturi effect device 27 to the main tank 20. Said secondary discharge path 14d further comprises an incorporation device 28, especially an incorporation hopper, for containing a product to be incorporated, such as a liquid or powdered crop protection product. The Venturi effect device 27 is further designed to suck the product to be incorporated contained in the incorporation device 28, when said secondary discharge path 14d is open and the liquid delivered by the pump 13 circulates through the Venturi effect device 27. In this manner, the product sucked by the Venturi effect device 27 is incorporated into the liquid circulating through the Venturi effect device 27 to fill the main tank 20 with a mixture of said liquid and said product. The liquid discharged by the pump 13 may be clear water from the rinse tank(s) 24 of the

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corresponding open secondary suction path 21c or, through the inlet hydraulic connector 23 of the corresponding open secondary suction path 21b, from a clear water source

external to the spraying system 10. Said secondary discharge path 14d thus provides a product incorporation function of the agricultural spraying system 10. The Venturi effect

device 27 forms an example of hydraulic members designed to operate over a predetermined pressure range, so that a pressure regulation of said secondary discharge

path 14d by the regulation valve 15 is more appropriate than a flow regulation.

One 14e of the secondary discharge paths 14b-14g, for example, connects the outlet 17 of the pump 13 to the main tank 20, so as to fill the main tank 20 with the

liquid discharged by the pump 13. The liquid discharged by the pump 13 may be treatment liquid from, through the inlet hydraulic connector 23 of the corresponding open secondary

suction path 21b, a treatment liquid source external to the spraying system 10. Said secondary discharge path 14e thus provides a filling function for the spraying system 10. A

pressure regulation to protect the pipeline forming said secondary discharge path 14e from overpressure is here more advantageous.

One 14f of the secondary discharge paths 14b-14g comprises, for

example, an external cleaning device 29, such as a hydraulic gun, so as to clean the exterior of the spraying system 10 with the liquid delivered by the pump 13. The liquid discharged

by the pump 13 may be clear water from the rinse tank(s) 24 of the corresponding open secondary suction path 21c or, through the inlet hydraulic connector 23 of the

corresponding open secondary suction path 21b, from a clear water source external to the spraying system 10. Said secondary discharge path 14f thus provides an external cleaning

function of the spraying system 10. The external cleaning device 29 forms an example of hydraulic members designed to operate over a predetermined pressure range, so that a

pressure regulation of said secondary discharge path 14f by the regulation valve 15 is more appropriate.

One 14g of the secondary discharge paths 14b-14g comprises, for

example, an output hydraulic connector 30 for reversible connection to a tank external to the spraying system 10, so as to transfer the liquid discharged by the pump 13 to said

external tank. Said secondary discharge path 14g thus provides a transfer function of the

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spraying system 10. A Pressure regulation is more advantageous here in order to protect the pipeline forming said secondary discharge path 14g from overpressure.

The spraying system 10 further comprises, for example, an electronic control unit 31.

The control unit 31 may comprise an input interface, an output interface, a data memory, a program memory, a microprocessor as well as at least one

communication bus connecting them to each other.

The input interface is for example connected to a user interface (not represented) through which a farmer communicates with the control unit 31. The user

interface may be installed in a tractor cab. The output interface is, for example, connected to the regulation valve

15, the discharge valves 18a-18g and optionally the suction valves 22a-22c. A regulation flow rate value can be stored in the data memory. The

regulation flow rate value may be pre-stored in the data memory, stored in the data memory by the farmer through the user interface and/or calculated and stored in the data

memory by the control unit 31. The calculation of the regulation flow rate value, based on

measured data of the spraying system 10 and the agricultural machine, such as their speed of travel in the field of plants to be treated, is well known to the skilled person and will

therefore not be detailed here. The regulation flow rate value is assigned to the regulation flow rate. When the spraying system 10 comprises several main discharge paths 14a, the

regulation flow rate value is for example common to said main discharge paths 14a. Of course, when the spraying system 10 comprises one or more

secondary discharge paths 14b-14g that are more appropriately flow-regulated, the or each of said secondary discharge paths 14b-14g has a corresponding regulation flow rate value,

for example. The one or more regulation flow rate values corresponding to said one or more secondary discharge paths 14b-14g may be stored in the data memory, which

regulation flow rate values may be pre-stored in the data memory and/or stored in the data

memory by the farmer through the user interface. These regulation flow rate values may be different for each of said secondary discharge paths 14b-14g or common to a plurality

of said secondary discharge paths 14b-14g.

Oneormorefirstregulationpressurevaluesmaybestoredinthedata memory.Theone or more first regulation pressure valuesmay be pre-stored in the data

memory and/or stored in the data memory by the farmer through the user interface. For example, each secondary discharge path 14b-14g has a corresponding first regulation

pressure value. These first regulation pressure values may be different for each secondary discharge path 14b-14g or common to multiple secondary discharge paths 14b-14g. A first

regulation pressure value may also correspond to the main discharge path(s) 14a.

One or more second regulation pressure values may be stored in the data memory. The one or more second regulation pressure values may be pre-stored in the data

memory and/or stored in the data memory by the farmer through the user interface. For example, the second regulation pressure value is assigned to the second regulation

pressure. Alternatively, each second regulation pressure value corresponds to a predetermined flow rate range. The flow rate ranges can be stored in the data memory.

The flow rate ranges and their corresponding second regulation pressure values can be pre stored in the data memory and/or stored in the data memory by the farmer through the

user interface. The second regulation pressure value assigned to the second regulation

pressure is then dependent on the flow rate range. The control unit 31 may be designed to command the regulation valve 15

to selectively flow- or pressure-regulate, depending on the open discharge path(s) 14a-14g, said open discharge path(s) 14a-14g. In this way, the discharge path(s) 14a-14g are flow- or

pressure-regulated, depending on what is most appropriate for them. The control unit 31 may especially be designed to command the

regulation valve 15 to flow-regulate the open discharge path(s) 14a-14g, when one of the open discharge path(s) 14a-14g is predetermined as being to be flow-regulated, and to

pressure-regulate the open discharge path(s) 14a-14g, when none of the open discharge path(s) 14a-14g is predetermined as being to be flow-regulated.

The predetermination of each discharge path 14a-14g as being to be flow

or pressure-regulated is, for example, pre-stored in the data memory. As noted above, the one or more main discharge paths 14a are for

example predetermined as being to be flow-regulated, with the agricultural spraying

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function being to be flow-regulated. The or each main discharge path 14a may also be predetermined asto be pressure-regulated, when the three-wayvalve 51occupiesthe first

position, and selectively predetermined as to be flow or pressure-regulated, when the three-way valve 51occupies the second position. The selection of the predetermination of

the or each main discharge channel 14a as being to be flow- or pressure-regulated for can then be made by the farmer through the user interface. The agricultural spraying function

can then be flow- or pressure-regulated.

The secondary discharge paths 14b-14g are for example predetermined as being to be pressure-regulated. The stirring, rinsing, product incorporation, filling,

external cleaning and/or transfer functions are therefore to be pressure-regulated. The control unit 31 may further be designed to: - when the or at least one of the open discharge paths 14a-14g is predetermined as

being to be flow-regulated:

o if applicable, when the spraying system 10 comprises one or more secondary discharge paths 14b-14g predetermined as being to be flow-regulated, assign the regulation flow rate value corresponding to said one or more open

discharge paths 14a-14g to the regulation flow rate; and then o command the regulation valve 15 to regulate the liquid flow rate in said open

discharge path 14a-14b to the regulation flow rate; - when none of the open discharge path(s) 14a-14g is predetermined as being to be

flow-regulated and the open discharge path(s) 14a-14g is predetermined as being to be pressure-regulated:

o assign the first regulation pressure value corresponding to said open discharge path(s) 14a-14g to the first regulation pressure; and then

o command the regulation valve 15 to regulate the liquid pressure in the open discharge path(s) 14a-14g to the first regulation pressure; - if applicable, when the secondary discharge path 14b providing the stirring

function is open and one or more other discharge paths 14a, 14c-14g, especially the main discharge path(s) 14a, are open:

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o optionally, assign to the second regulation pressure the value of the second regulation pressure corresponding to the flow rate range in which the flow

rate of liquid circulating in the open discharge channel(s) 14a-14g is included, this flow rate being especially measured by the flow meter 32

which will be described later; then o command, at the same time as the regulation valve 15, the discharge valve

18b by means of which said secondary discharge path 14b is connected to

the outlet 17 of the pump 13, to regulate the liquid pressure in said secondary discharge path 14b to the second regulation pressure.

The liquid circuit 12 may further comprise a flow meter 32 designed to measure the liquid flow rate downstream of the outlet 17 of the pump 13, especially of the

liquid circulating in the main discharge path(s) 14a. For this, the flow meter 32 is installed downstream of the pump 13, especially along the or one of the main discharge paths 14a.

The flow meter 32 may also be installed upstream of the discharge paths 14a-14g. The flow meter 32 may be connected to the input interface of the control unit 31.

Alternatively, a plurality of flow meters may be provided, each flow meter

being designed to measure flow rate of the liquid circulating in one of the discharge paths 14a-14g, especially in one of the discharge paths 14a-14g that are predetermined as being

to be flow-regulated. For this, each flow meter is installed downstream of the pump 13 along the discharge path 14a-14g whose liquid flow rate it measures.

The liquid circuit 12 may also comprise a first pressure sensor 33 designed to measure pressure of the liquid downstream of the outlet 17 of the pump 13 and

upstream of the discharge paths 14a-14g. For this, the first pressure sensor 33 is installed downstream of the outlet 17 of the pump 13 and upstream of the discharge paths 14a-14g.

The first pressure sensor 33 may be connected to the input interface of the control unit 31. Alternatively, a plurality of first pressure sensors may be provided, each

first pressure sensor being designed to measure pressure of the liquid circulating in one of

the discharge paths 14a-14g, especially in one of the discharge paths 14a-14g that are predetermined as being to be pressure-regulated. For this, each first pressure sensor is

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installed downstream of the pump 13, along the discharge path 14a-14g whose liquid pressure it measures.

The liquid circuit 12 may further comprise a second pressure sensor 53 designed to measure the liquid pressure along the or one of the main discharge paths 14a.

For this, the second pressure sensor 53 is installed along said main discharge path 14a, especially closest to the spray nozzles 19. The second pressure sensor 53 may be connected

to the input interface of the control unit 31.

The control unit 31 may further be designed to selectively command, as a function of the open discharge path(s) 14a-14g:

- opening and closing of the regulation valve 15 as a function of the flow rate measured by the flow meter 32, so as to keep the liquid flow rate in said discharge

path(s) 14a-14g open, overall to the regulation flow rate, or - opening and closing of the regulation valve 15 as a function of the pressure

measured by the first pressure sensor 33 or the second pressure sensor 53, so as

to keep the liquid pressure in said open discharge path(s) 14a-14g, overall to the

first regulation pressure. In other words, in the case of flow regulation, the or one of the open

discharge path(s) 14a-14g being especially predetermined as being to be flow-regulated, when the flow rate measured by the flow meter 32 is less than the regulation flow rate, the

control unit 31 commands the regulation valve 15 to open further, so as to increase the flow rate in the open discharge path(s) 14a-14g until the regulation flow rate is reached.

When, on the other hand, the flow rate measured by the flow meter 32 is greater than the regulation flow rate, the control unit 31 commands the regulation valve 15 to close further,

so as to decrease the flow rate in the open discharge path(s) 14a-14g until the regulation flow rate is reached. In this way, it is possible to regulate the flow rate in the open discharge

path(s) 14a-14g, and thus to maintain it overall to the regulation flow rate. The flow rate in

the open discharge channel(s) 14a-14g thus oscillates about the regulation flow rate, the difference between the regulation flow rate and these oscillations however being negligible

relative to the regulation flow rate.

.10

In the case of pressure regulation, none of the open discharge path(s) 14a-14g being especially predetermined as being to be flow-regulated, when the pressure

measured by the first pressure sensor 33 or the second pressure sensor 53 is lower than the first regulation pressure, the control unit 31 commands the regulation valve 15 to close

further, so as to increase the pressure in the open discharge path(s) 14a-14g until it reaches the first regulation pressure. When, on the other hand, the pressure measured by the first

pressure sensor 33 or the second pressure sensor 53 is higher than the first regulation

pressure, the control unit 31 commands the regulation valve 15 to open further, so as to decrease the pressure in the open discharge path(s) 14a-14g until the first regulation

pressure is reached. In this way, it is possible to regulate the pressure in the open discharge path(s) 14a-14g, and thus to maintain it overall to the first regulation pressure. It will be

understood that once the pressure in the open discharge path(s) 14a-14g has reached the first regulation pressure, the pressure in the open discharge path(s) 14a-14g oscillates

about the first regulation pressure, the difference between the first regulation pressure and these oscillations however being negligible relative to the first regulation pressure. The

second pressure sensor 53 is only used for pressure regulation in the case where the main

discharge channel(s) 14a is/are open and predetermined as being to be pressure-regulated. The first pressure sensor 32 serves in other cases.

The liquid circuit 12 also comprises, for example, a third pressure sensor 34 designed to measure pressure of the liquid downstream of the discharge valve 18b

through which the secondary discharge path 14b performing the stirring function is connected to the output 17 of the pump 13. For this, the third pressure sensor 34 is

installed downstream of said discharge valve 18b, along said secondary discharge path 14b. The second pressure sensor 34 may be connected to the input interface of the control unit

31. The control unit 31 may further be designed to control opening and closing of said discharge valve 18b as a function of the pressure measured by the third pressure sensor

34, when said secondary discharge path 14b is open, so as to maintain the liquid pressure

in said secondary discharge path 14b, overall at the second regulation pressure. The pressure regulation operation described above with respect to regulation valve 15 is

applicable mutatis mutandis to said discharge valve 18b.

Figure 2 shows an example of a regulation valve 15. The regulation valve 15 comprises a valve body 151 defining an air

chamber 152 and a liquid chamber 153 separated from each other by a slide valve 154 comprising a seat 155 arranged in the liquid chamber 153.

The regulation valve 15 may also comprise a membrane 156 integral with the valve body 151 on its peripheral portion 157 on the one hand, and with the slide valve

154 on its central portion on the other hand.

The air chamber 152 communicates, for example, with a pneumatic circuit (not represented) designed to pilot an air pressure in the air chamber 152.

For this, the pneumatic circuit comprises, for example, an air supply conduit through which air is supplied to the air chamber 152 so as to increase air pressure

in said air chamber 152, and an air exhaust conduit through which air is exhausted from the air chamber 152 so as to decrease air pressure in said air chamber 152. The supply and

exhaust conduits may each be provided with a valve designed to open and close said supply or exhaust conduit. The valves may be connected to the output interface of the control unit

31. The pneumatic circuit may further comprise a fourth pressure sensor 160 (Figure 1)

designed to measure air pressure in the air chamber 152. The fourth pressure sensor 160 may be connected to the input interface of the control unit 31.

The liquid chamber 153 comprises an inlet port 158 communicating with the outlet 17 of the pump 13, as well as an outlet port 159 communicating with the inlet

16 of the pump 13. The slide valve 154 is further designed to move in the valve body 151, to

move the seat 155 of said slide valve 154 toward or away from the outlet port 159 of the liquid chamber 153, as a function of a difference between air pressure in the air chamber

152 and pressure of the liquid circulating in the liquid chamber 153, from the inlet port 158 toward the outlet port 159. Thus, by piloting air pressure in the air chamber 152 of the

regulation valve 15, the flow rate or pressure of the liquid flowing through the regulation

valve 15 and thus the flow rate or pressure of the liquid flowing through the open discharge path(s) 14a-14g can be varied.

The control unit 31 may also be designed to:

LU

- determine one or more closed discharge path(s) 14a-14g to open and one or more open discharge path(s) 14a-14g to close;

- decrease air pressure in the air chamber 152 of the regulation valve 15, especially by opening the exhaust conduit of the pneumatic circuit by means of the valve of

said exhaust conduit; - open the closed discharge conduit(s) 14a-14g to open and closing the open

discharge conduit(s) 14a-14g to close, especially by means of the discharge valves

18a-18g, simultaneously or successively, in either order; - if applicable, when the spraying system 10 comprises one or more secondary

discharge paths 14b-14g predetermined as being to be flow-regulated and at least one of the open discharge paths 14a-14g is predetermined as being to be flow

regulated, assign the regulation flow rate value corresponding to said open discharge path(s) 14a-14g to the regulation flow rate; - if applicable, when none of said open discharge path(s) 14a-14g is predetermined

as being to be flow-regulated, assign the first regulation pressure value

corresponding to said open discharge path(s) 14a-14g to the first regulation

pressure; - increase air pressure in the air chamber 152 of the regulation valve 15, especially

by opening the supply conduit of the pneumatic circuit by means of the valve of said supply conduit, until selectively, as a function of the discharge path(s) 14a

14g thus opened: o the flow rate of liquid circulating in the open discharge path(s) 14a-14g

reaches the regulation flow rate, especially when the or at least one of the open discharge paths 14a-14g is predetermined as being to be flow

regulated, or

o the pressure of liquid circulating in the open discharge path(s) 14a-14g

reaches the first regulation pressure, especially when none of the open discharge path(s) 14a-14g is predetermined as being to be flow-regulated;

- selectively regulate, as a function of the open discharge path(s) 14a-14g: tL o the flow rate of liquid circulating in the open discharge path(s) 14a-14g, to the regulation flow rate, especially when the or at least one of the open discharge path(s) 14a-14g is predetermined as being to be flow-regulated, or o the pressure of liquid circulating in the open discharge path(s) 14a-14g to the first regulation pressure, especially when none of the open discharge path(s) 14a-14g is predetermined as being to be flow-regulated.

In this manner, when the control unit 31 opens the closed discharge path(s) 14a-14g to open and closes the open discharge path(s) 14a-14g to close, air

pressure in the air chamber 152 of the regulation valve 15 is low and stresses applied by the regulation valve 15 to the liquid downstream of the pump 13 are reduced. This prevents

any overpressure of the liquid circulating in the liquid circuit 12 downstream of the pump 13, which could lead to water hammer and thus damage to the liquid circuit 12. Once the

closed discharge paths 14a-14g have been opened and the open discharge paths 14a-14g have been closed, the air pressure in the air chamber 152 of the regulation valve 15 can be

safely re-increased to flow- or pressure-regulate the discharge path(s) 14a-14g thus

opened. In this way, changes in the function of the spraying system 10 are made without risk to the liquid circuit 12.

The control unit 31is, for example, designed to: - receive instructions to open one or more closed discharge paths 14a-14g and, if

applicable, to close one or more open discharge paths 14a-14g; - determine, from said instructions received, the one or more closed discharge

path(s) 14a-14g to open and the one or more open discharge path(s) 14a-14g to close.

The control unit 31 may determine the one or more open discharge path(s) 14a-14g to close directly from instructions to close one or more open discharge

paths 14a-14g or indirectly from instructions to open one or more closed discharge paths

14a-14g.

The instructions to open one or more closed discharge path(s) 14a-14g and, if applicable, to close one or more open discharge path(s) 14a-14g may be sent by the

farmer through the user interface. The control unit 31 may further be designed to decrease air pressure in

the air chamber 152 of the regulation valve 15 for a predetermined target period. A target period value may be stored in the data memory. The target period value may be pre-stored

in the data memory and/or stored in the data memory by the farmer through the user

interface. The target period value is assigned to the target period. The control unit 31 may especially be designed to open the exhaust conduit of the pneumatic circuit, especially by

means of the valve of said exhaust conduit, during the target period, so as to exhaust air from the air chamber 152 of the regulation valve 15 and to decrease air pressure in said air

chamber 152. Alternatively, the control unit 31 is designed to decrease air pressure in

the air chamber 152 of the regulation valve 15 until said air pressure reaches a predetermined target pressure, especially until the air pressure measured by the fourth

pressure sensor 160 reaches the target pressure. A target pressure value may be stored in

the data memory. The target pressure value may be pre-stored in the data memory and/or stored in the data memory by the farmer through the user interface. The target pressure

value is assigned to the target pressure. The control unit 31 may especially be designed to open the exhaust conduit of the pneumatic circuit, especially by means of the valve of said

exhaust conduit, until the target pressure is reached. Figure 3 shows a method 100 for piloting the spraying system 10. The

method 100 can be stored in the program memory of the control unit 31. The method 100 comprises a step 101of selectively regulating, by means

of the regulation valve 15, depending on the open discharge path(s) 14a-14g, the flow rate of liquid circulating in the open discharge path(s) 14a-14g to the regulation flow rate,

especially when at least one of the open discharge path(s) 14a-14g is predetermined as

being to be flow-regulated, or the pressure of liquid flowing in the open discharge path(s) 14a-14g to the first regulation pressure, especiallywhen none of the open discharge path(s)

14a-14g is predetermined as being to be flow-regulated.

L_

When the secondary discharge path 14b providing the stirring function is open and one or more other discharge paths 14a, 14c-14g, especially the main discharge

path(s) 14a, is/are open, the method 100 further comprises, for example, a step 102 of regulating, by means of the discharge valve 18b connecting the outlet 17 of the pump 13

to said secondary discharge path 14b, liquid pressure in said secondary discharge path 14b to the second regulation pressure. The selective regulation step 101 and the step 102 of

regulating pressure in said secondary discharge path 14b are implemented at the same

time. Optionally, prior to the regulation step 102, the method 100 comprises a step (not represented) of assigning, to the second regulation pressure, the value of the second

regulation pressure corresponding to the flow rate range in which the flow rate of liquid circulating in the open discharge path(s) 14a-14g, especially measured by the flow meter

32, is included. When the spraying system 10 comprises one or more secondary

discharge path(s) 14b-14g predetermined as being to be flow-regulated and at least one of the open discharge paths 14a-14g is predetermined as being to be flow-regulated, the

method 100 comprises, for example, a step (not shown) of assigning the regulation flow

rate value corresponding to said one or more open discharge path(s) 14a-14g to the regulation flow rate.

When none of said one or more open discharge path(s) 14a-14g is predetermined as being to be flow-regulated, the method 100 comprises, for example, prior to the selective regulation step 101, a step 103 of assigning the first regulation pressure value corresponding to said one or more open discharge path(s) 14a-14g, to the

first regulation pressure. The method 100 may also comprise, prior to the selective regulation step

101: - a step 104 of determining one or more closed discharge path(s) 14a-14g to open

and one or more open discharge path(s) 14a-14g to close; - a step 105 of decreasing air pressure in the air chamber 152 of the regulation valve

15;

- a step 106 of opening the closed discharge path(s) 14a-14g to open and closing the open discharge path(s) 14a-14g to close, simultaneously or successively, in

either order; - if applicable, when the spraying system 10 comprises one or more secondary

discharge paths 14b-14g predetermined as being to be flow-regulated and at least one of the open discharge paths 14a-14g is predetermined as being to be flow

regulated, the step of assigning the regulation flow rate value corresponding to

said one or more open discharge paths 14a-14g to the regulation flow rate; - if applicable, when none of the open discharge path(s) 14a-14g is predetermined

as being to be flow-regulated, the step 103 of assigning the first regulation pressure value corresponding to said open discharge path(s) 14a-14g to the first

regulation pressure; - a step 107 of increasing air pressure in the air chamber 152 of the regulation valve

15 until selectively, as a function of the discharge path(s) 14a-14g thus opened: o the flow rate of liquid circulating in the open discharge path(s) 14a-14g

reaches the regulation flow rate, especially when the or at least one of the

open discharge path(s) 14a-14g is predetermined as being to be flow regulated,

or o the pressure of liquid circulating in the open discharge path(s) 14a-14g

reaches the first regulation pressure, especially when none of the open discharge path(s) 14a-14g is predetermined as being to be flow-regulated.

The method 100 may also comprise a step 108 of receiving instructions to open one or more closed discharge paths 14a-14g and, if applicable, to close the one or

more open discharge paths 14a-14g, the one or more closed discharge paths 14a-14g to open and the one or more open discharge paths 14a-14g to close then being determined

in the corresponding step 104 from said instructions. Said instructions are, for example,

sent by the farmer through the user interface. The one or more open discharge paths 14a 14g to close may further be determined directly from instructions to close one or more open discharge paths 14a-14g or indirectly from instructions to open one or more closed discharge paths 14a-14g.

The air pressure in the air chamber 152 of the regulation valve 15 is for example decreased in the corresponding step 105 for a predetermined target period. For

this, the exhaust conduit of the pneumatic circuit may be opened during the target period, so as to discharge air from the air chamber 152 of the regulation valve 15 and decrease air

pressure in said air chamber 152.

Alternatively, the air pressure in the air chamber 152 of the regulation valve 15 is decreased in the corresponding step 105 until said air pressure reaches a

predetermined target pressure, especially until the air pressure measured by the fourth pressure sensor 160 is equal to the target pressure. The exhaust conduit of the pneumatic

circuit may be opened until the target pressure is reached. In the claims which follow and in the preceding description of the

invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features

but not to preclude the presence or addition of further features in various embodiments of the invention.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part

of the common general knowledge in the art, in Australia or any other country.

Claims (8)

LU CLAIMS

1. A spraying system (10) for an agricultural machine, comprises a spray

ramp (11), a control unit (31) and a liquid circuit (12) itself comprising: - a pump (13) comprising an inlet (16) and an outlet (17), the pump (13) being

designed to suck a liquid through the inlet (16) and to discharge the sucked liquid through the outlet (17), - discharge paths (14a-14g) each connected, upstream, to the outlet (17) of the

pump (13) through a discharge valve (18a-18g) designed to open and close said discharge path (14a-14g), at least one (14a) of the discharge paths (14a-14g),

called a main discharge path, comprising spray nozzles (19) mounted to the spray ramp (11) and designed to spray liquid onto plants of a field to be treated, the

other discharge path(s) (14b-14g), called secondary discharge path(s), being devoid of spray nozzles mounted to the spray ramp (11), - a regulation valve (15),

the spraying system (10) being characterised in that the regulation valve

(15) is connected, upstream, to the outlet (17) of the pump (13) and, downstream, to the

inlet (16) of the pump (13), the regulation valve (15) being further designed to selectively regulate, as a function of said open discharge path(s) (14a-14g), a liquid flow rate in the

open discharge path(s) (14a-14g) to a predetermined regulation flow rate, or a liquid pressure in the open discharge path(s) (14a-14g) to a first predetermined regulating

pressure, and in that the control unit (31) is designed to command the regulation valve (15) to flow-regulate the open discharge path(s) (14a-14g), when at least one of the open

discharge path(s) (14a-14g) is predetermined as being to be flow-regulated, and to pressure-regulate the open discharge path(s) (14a-14g) when none of the open discharge

path(s) (14a-14g) is predetermined as being to be flow-regulated.

2. The spraying system (10) according to claim 1, wherein the one or more

main discharge paths (14a) is (are) predetermined as being to be flow-regulated and the

4./

one or more secondary discharge paths (14b-14g) is (are) predetermined as being to be pressure-regulated.

3. The spraying system (10) according to claim 1 or claim 2, wherein the

regulation valve (15) comprises a valve body (151) defining an air chamber (152) and a liquid chamber (153) separated from each other by a slide valve (154) comprising a seat

(155) arranged in the liquid chamber (153), the liquid chamber (153) comprises an inlet

port (158) communicating with the outlet (17) of the pump (13) and an outlet port (159) communicating with the inlet (16) of the pump (13), the slide valve (154) being further

designed to move in the valve body (151), as a function of a difference between an air pressure in the air chamber (152) and a pressure of the liquid circulating in the liquid

chamber (153), from the inlet port (158) toward the outlet port (159), so as to move the seat (155) toward or away from the outlet port (159).

4.The spraying system (10) accordingto claim 3, comprisinga control unit

(31) designed to: - determine one or more closed discharge path(s) (14a-14g) to open and one or

more open discharge path(s) (14a-14g) to close; - decrease air pressure in the air chamber (152) of the regulation valve (15);

- open the one or more closed discharge path(s) (14a-14g) to open and close the

one or more open discharge path(s) (14a-14g) to close, simultaneously or successively, in either order; - increase air pressure in the air chamber (152) of the regulation valve (15), until

selectively, as a function of the discharge path(s) (14a-14g) thus opened:

o the flow rate of liquid circulating in the open discharge path(s) (14a-14g) reaches the regulation flow rate,

or

o the pressure of liquid circulating in the open discharge conduit(s) (14a-14g) reaches the first regulation pressure.

5. The spraying system (10) according to claim 4, wherein the control unit (31) is designed to decrease air pressure in the air chamber (152) of the regulation valve

(15) for a predetermined target period or until said air pressure reaches a predetermined target pressure.

6. A method (100) for piloting a spraying system (10) for an agricultural

machine according to one of claims 1 to 5, comprising a step (101) of selectively regulating,

by means of the regulation valve (15), as a function of the open discharge path(s) (14a 14g), the flow rate of liquid circulating in the open discharge path(s) (14a-14g) to the

regulation flow rate, or the pressure of liquid circulating in the open discharge path(s) (14a 14g) to the first regulation pressure, and wherein, during the selective regulation step

(101), the flow rate of liquid circulating in the open discharge path(s) (14a-14g) is regulated to the regulation flow rate, when the or at least one of the open discharge path(s) (14a

14g) is predetermined as being to be flow-regulated, and the pressure of liquid circulating in the open discharge path(s) (14a-14g) is regulated to the first regulating pressure, when

none of the open discharge path(s) (14a-14g) is predetermined as being to be flow

regulated.

7. The method (100) according to claim 6, the spraying system (10) being in accordance with any claims 3 to 5, comprising, prior to the selective regulation step

(101): - a step (104) of determining one or more closed discharge path(s) (14a-14g) to

open and one or more open discharge path(s) (14a-14g) to close; - a step (105) of decreasing air pressure in the air chamber (152) of the regulation

valve (15); - a step (106) of opening the one or more closed discharge path(s) (14a-14g) to open

and closing the one or more open discharge path(s) (14a-14g) to close,

simultaneously or successively, in either order; - a step (107) of increasing air pressure in the air chamber (152) of the regulation

valve (15) until, selectively, as a function of the discharge path(s) (14a-14g) thus opened, the flow rate of liquid circulating in the open discharge path(s) (14a-14g) reaches the regulation flow rate, or the pressure of liquid circulating in the open discharge path(s) (14a-14g) reaches the first regulation pressure.

8. The method (100) according to claim 7, wherein during the decrease step (104), the air pressure in the airchamber (152) of the regulation valve (15) is decreased

for a predetermined target period or until said air pressure reaches a predetermined target

pressure.