Process of operating the air conditioning system of a cab of a machine

A process for operating a machine having a cab and an air conditioning system. The air conditioning system includes a circuit configured for supplying the cab with air coming from a recycling branch fed with air coming from an interior of the cab and an exterior branch fed with air coming from an exterior of the cab, a blowing device, and a filtration system. The process includes the steps of operating the air conditioning system in a regular procedure, monitoring of a signal indicative of a potential contamination of the cab, and upon the detection of such signal, operating the air conditioning system in a flushing procedure. The flushing procedure includes increasing the air flow supplied in the cab, controlling a flow of air to supply air only from the exterior branch, and opening an exhaust flap within the cab for increasing a flow of air evacuated from the cab.

FIELD OF THE INVENTION

The present invention relates to a process of operating the air conditioning system of a cab of a machine, and a machine, in particular an agricultural machine, including a cab equipped with an air conditioning system which is adapted to be operated according to such a process.

BACKGROUND OF THE INVENTION

Agricultural machines are known, including a motorized support structure which is equipped with a driver station and movable in particular along rows of plants and/or furrows of an agricultural field. A spreading unit can be mounted on the structure for straddling at least one of the rows and spreading determined measures of at least one treatment product on the rows.

In particular, such machines are driven by a human operator seating in a closed cab of the driver station for actuating the commands means for moving the machine and/or operating the spreading unit.

The spreading unit can spread treatment products, such as phytosanitary products, insecticides or fertilizers, on the harvest plants and/or the plowed soil of an agricultural field, such as a vineyard or an orchard. Treatment products used in the agricultural domain may be harmful. In particular, during spreading operations, a quantity of such products may diffuse in the air, in particular in the form of dusts, aerosols and/or vapors, and form air pollutants which, if there are inhaled by the operator, in particular repeatedly, may cause undesired effects.

For limiting the exposure of the operator to such air pollutants, cabs are generally equipped with air conditioning systems that are adapted to condition the air circulating in the cabs, in particular by feeding the cabs with air that is mainly free from such pollutants.

In particular, such air-conditioning systems are known, including:a circuit for supplying the cab with air coming from a recycling branch, that is fed with recycled air coming from the interior of the cab, and an exterior branch, that is fed with air coming from the exterior of the cab;a blowing device for providing an air flow inside the circuit;filtration means for removing pollutants from the air blown in the cab through the circuit;
the air-conditioning systems being operated according to a regular procedure to balance the air supplied by each of the recycling and exterior branches, for example to supply the cab with fresh air comprising approximately 80% of recycled air coming from the recycling branch and approximately 20% of exterior air coming from the exterior branch.

Besides, such air-conditioning systems may comply with strict regulatory texts, such as the European standard EN-15695, in particular as regards the air flow debit, the air pressurization inside the cab and the quality of the filtration systems. For example, this standard defines four levels or categories for the security provided to the operator, from a minimum security level (category 1) wherein the health risks are minimal, for instance when the machine is driven on a road, to a maximum security level (category 4), wherein the machine is driven on a field to spray highly polluting and volatile products.

However, these requirements are not totally satisfactory, as they cannot efficiently protect the operator in case of a contamination of the cab with air pollutants as described above. Indeed, when polluted air enters into the cab, for example upon opening of an access of the cab by the operator, the polluted air is difficult and slow to evacuate, in particular as the air provided by the air-conditioning system mainly comprises recycled air coming from the cab, i.e. potentially polluted air.

What is needed in the art is an efficient air conditioning system process of operating the air conditioning system of the cab for filtering air pollutants diffused around the cab.

SUMMARY OF THE INVENTION

According to an exemplary embodiment of the invention, a process of operating the air conditioning system of a cab of a machine is provided, the air-conditioning system including:a circuit for supplying the cab with air coming from a recycling branch fed with air coming from the interior of the cab and an exterior branch fed with air coming from the exterior of the cab;a blowing device for providing an air flow inside the circuit;a filtration system for removing pollutants from the air blown in the cab through the circuit.

The air conditioning system being operable to control, e.g. balance, in the supplied air flow, the amount of air coming from the recycling branch versus the amount of air coming from the exterior branch. The process includes a regular procedure wherein the air-conditioning system is operated to balance the air flow to supply air coming from each of the recycling and exterior branches. The process further includes the monitoring of a signal indicative of a potential contamination of the interior of the cab and, upon the detection of such signal, a flushing procedure wherein the air conditioning system is operated to:increase the flow of air supplied into the cab by the blowing device through the circuit;control the flow of air to supply air coming only from the exterior branch by closing the recycling branch; andopen an exhaust flap within the cab for increasing the flow of air evacuated from the cab. The flushing procedure being performed for a determined period of time before performing again the regular procedure.

According to another exemplary embodiment of the present invention, there is provided a machine, in particular an agricultural machine, including a cab equipped with an air conditioning system which is adapted to be operated according to such a process.

DETAILED DESCRIPTION OF THE INVENTION

The machine can be an agricultural machine arranged for the mechanical or pressurized spreading of treatment products, such as phytosanitary products, insecticides or fertilizers, on the harvest plants and/or the plowed soil of an agricultural field, such as a vineyard or an orchard.

To do so, the machine may include a motorized support structure which is equipped with a driver station and movable in particular along rows of plants and/or furrows of an agricultural field. A spreading unit can be mounted on the structure for straddling at least one of the rows and spreading determined amounts of at least one treatment product on the rows.

In particular, the spreading unit can be mounted on the support structure permanently or removably, so as to be replaceable by other equipment and accessories, for example harvesting equipment, pruning equipment, or equipment for working the soil.

The machine is in particular adapted to be driven by a human operator. To do so, the driver station comprises a closed cab1wherein the operator is intended to seat for actuating the commands for moving the machine and/or operating the spreading unit.

As shown inFIG. 1, the cab1includes a front windshield2made from a substantially transparent and solid material, for example laminated glass, for protecting the operator from wind and/or rain while ensuring a good visibility to allow the operator to safely drive and operate the machine, as well as a device3for remotely controlled washing of the windshield, in particular with an adapted product, for removing dirt that can potentially hinder the visibility. Moreover, the cab1includes at least an access, in particular a lateral access door4, for allowing the operator to enter and to leave the cab1.

Direct contact with treatment products used in the agricultural domain may be harmful. In particular, during spreading operations, a quantity of such products may diffuse in the air, in particular in the form of dusts, aerosols and/or vapours, and then may form air pollutants which, if they are inhaled by the operator, in particular repeatedly, may cause in the long term undesired effects.

For limiting the risk of exposure of the operator to such air pollutants, the cab1is equipped with an air conditioning system5that is adapted to condition the air circulating in the cab, in particular by feeding the cab with air that is principally free from such pollutants.

The air conditioning system5is implemented in the roof of the cab1, in particular into a sealed compartment6which is fixed, for example by gluing, underneath the roof, and which is accessible from the exterior of the cab1by way of an upper removable maintenance cover7. In particular, the maintenance cover7includes a peripheral edge which is equipped with a sealing gasket8, so as to ensure the sealed closing of the compartment6.

The air conditioning system5may also include:a control board card21for steering the operation of the system, in particular upon communication with command means implemented within the cab1, according to a predetermined process;a circuit9which supplies the cab1with air coming from a recycling branch9afed with air coming from the interior of the cab and an exterior branch9bfed with air coming from the exterior of the cab;a blowing device10(e.g., a fan) for providing an air flow inside the circuit;filtration means11for removing pollutants from the air blown in the cab through the circuit.

The air conditioning system5includes a filtration and pressurization set12which is arranged upstream the circuit9, the set including a central housing13, wherein the blowing device10is arranged, and two lateral housings14a,14b, wherein respectively a first filter11aand a second filter11bof the filtration system is arranged. As shown inFIG. 2B, the central13and lateral14a,14bhousings may be constituted by upper13u,14au,14buand lower13l,14al,14blhousing portions to be assembled together to form the housings. Moreover,FIGS. 2B and 4Brepresent schematically a filtration and pressurization set12according to respectively an embodiment of the invention.

The lateral housings14a,14bare in fluid communication with the exterior of the cab1, so as to allow circulation through the housings of air coming from the exterior and to remove pollutants from the exterior air by the filtration system11a,11barranged within the housings.

Further, the central housing13is in fluid communication with the lateral housings14a,14b, so as to allow the blowing into the exterior branch9bof an exterior air flow FE that has been filtered by at least one filtering system11a,11b.

The filtering system11,11a,11bmay be adapted to remove pollutants. The first filter11amay have a first filtration level, and the second filter11bmay have a second filtration level for filtering out pollutants. For example, the filters11a,11bmay comply with the requirements of at least the category 2 defined by standard EN-15695 so as to be able to remove at least the dust pollutants from the air flow to be blown into the cab1, and more particularly with the requirements of the maximum category 4 of the standard, so as to be able to remove not only dusts, but also aerosol and vapor pollutants from the air flow.

In the exemplary embodiment shown, the air conditioning system5includes first11aand second11bfilter that may comply with the requirements of respectively the categories 2 and 4 of the standard EN-15695. The filters may be made, for example, respectively from paper and from charcoal.

Moreover, the air conditioning system5may selectively switch between two filtration modes corresponding respectively to category 2 and 4 filtration levels, wherein the filters11a,11bare selectively put in fluid communication with the blowing device10according to the desired level of filtration.

As shown inFIGS. 2B and 4B, the switching devices comprise at least one filter selection valve15(FIG. 2B), and in particular two selection valves15a,15b(FIG. 4B), the valves being arranged in fluid communication paths16relaying the central housing13to respectively the first category 214aand the second category 414bfiltering housings. The valve(s) are operable to be selectively actuated, in particular by way of an actuator17to which the valve is linked through a connector (not shown), respectively in category 2 and 4 filtration modes, wherein the valve(s) close(s)—respectively open(s)—the fluid communication between the category 4 filtration housing14band the central housing13and open(s)—respectively close(s)—the fluid communication between the category 2 filtration housing14aand the central housing.

Thus, in a particularly advantageous manner, the operator can benefit from a high level of filtration only when required, in particular only during the performing of a spreading operation in an agricultural field, and can switch to a lower level of filtration, for example of category 2, when the risks of air pollution are lower, for example during road transport between an agricultural field and a farm or between fields. Such a configuration may limit the clogging of the category 4 filters11band may substantially increase its lifetime, which is quite short in relation to the lifetime of approximately 1 year of the category 2 filters.

In order to assess the saturation or clogging of the filters11a,11b, each housing14a,14bmay be provided with a pressure differential sensor S,FIG. 4B, which is connected by sensor lines to the upstream and downstream ends of the respective lateral housings14a,14b. Thus, the pressure differential sensor signal is constantly monitored by the sensors S and, upon the pressure differential exceeding a limit value, the operator is warned that the one or the other filters11a,11bneeds replacement, in particular by activating a communication device such as a lighting indicator button, a screen or speaker(s), implemented in the cab1.

The air conditioning system5further includes additional filters19that may be arranged at the fluid communication path between the interior of the cab1and the outlet of the recycling branch9a, so as to remove possible air pollutants from the recycled air flow coming from the cab interior. In the exemplary embodiment shown, the additional filters19are provided at the inlet of the recycling branch9a.

The air conditioning system5further includes a recycling valve27located in the recycling branch9a, e.g. downstream of the additional filters19, for selectively opening and closing the recycling branch.

Moreover, the air conditioning system5may include a HVAC device20(for Heating, Ventilation and Air Conditioning) which is arranged downstream of the circuit9for conditioning the air flow blown in the cab1through the circuit. The HVAC device including an inlet into which both of the circuit branches9a,9bend for feeding the HVAC device with the air flow to be conditioned and blown into the cab1. The HVAC device20includes heat exchangers for cooling or heating the passing air and a circulation blower for blowing the conditioned air into the interior of the cab1.

The process of operating the air conditioning system5may include the following steps.

In particular, the process may include a filtration mode selection procedure wherein the switching devices are operated to select one filtration mode, either upon manual activation of an appropriate way by the operator in the cab1, for example a button or a switch on a control board within the cab, or upon automatic detection of an appropriate signal corresponding to the actuation state of the spreading unit.

More precisely, the filtration mode selection procedure provides a first step A, in which the system assesses whether the cab1is provided with both category 2 and category 4 filters11a,11band puts the selection valves15,15a,15bin the category 2 filtration mode. The recycling valve27is in its default position, which is the open state to allow the flow FR of interior air through the recycling branch9ato the HVAC device20.

Afterward, the filtration mode selection procedure provides a second step B, wherein the air conditioning system5may be operated to put the selection valves15,15a,15bin the category 4 filtration mode. Here, the selection procedure provides for the monitoring of appropriate signals, for example the manual actuation of a command means in the cab1or the actuation/deactivation of the spreading unit, and to perform switching from one filtration mode to another, according to the results of the monitoring.

Additionally, the process can provide for performing the filtration mode selection procedure upon initial actuation I of the air conditioning system5. In particular, as shown inFIG. 5, the category 2 mode selection step A is performed just after the initial actuation step I, so as to put by default the filtration and pressurization set12in the category 2 filtration mode.

Afterwards, the process provides for monitoring an appropriate signal as described above and for performing the category 4 mode selection step B upon the detection of such signal. In particular, the process can provide for informing the operator that the filtration and pressurization set12is in the category 4 filtration mode, in particular by lighting an indicator button23and/or displaying an icon on a screen in the cab1.

The process then may automatically proceed to a step E for performing a regular procedure, described with reference toFIGS. 3 and 6A. Herein, the air conditioning system5is operated to balance the air supplied by each of the recycling9aand exterior9bbranches of the circuit9, whatever the filtration mode selected.

In particular, the air conditioning system5is operable to balance, in the supplied air flow, the amount of air coming from the recycling branch9aversus the amount of air coming from the exterior branch9b. Moreover, the regular procedure can provide for operating the air conditioning system5to supply the cab1with a total flow of air including approximately 80% of a flow FRof recycled air coming from the recycling branch9aand approximately 20% of a flow FEof exterior air coming from the exterior branch9b.

Moreover, to comply with the various standards, for example the requirements of at least the category 2 defined by standard EN-15695, the regular procedure can provide for operating the air conditioning system5, and in particular the blowing device10, so that the air flow FEfrom the exterior branch9bsupplied in the cab1presents a flow rate of at least 30 m3/h with an overpressure in the cab of at least 20 Pa.

As illustrated inFIG. 5, the process provides for performing the regular procedure upon initial actuation I of the air conditioning system5, the steps A, B of the filtration mode selection procedure being performed during the regular procedure just after the initial actuation step I.

Thus, during the regular procedure, the cab1is regularly supplied with a flow of fresh air FR, FEcoming from both the interior and the exterior of the cab1. The flow being previously filtered by appropriate filtration means11,11a,11b,19for removing pollutants generated in particular by the spreading product before being blown into the cab.

However, the regular procedure may not provide sufficient filtration for the operator from such pollutants when polluted air has already entered into the cab1. For example, upon opening by the operator of an access4of the cab, in particular as the flow of air FR, FE supplied by the air conditioning system5mainly includes a flow of recycled air FRcoming from the interior of the cab, i.e. potentially polluted air.

The process may further include the monitoring of a signal indicative of a potential contamination of the interior of the cab1and, upon the detection of such signal, the process may provide for performing a flushing procedure wherein the air conditioning system5is operated to remove the contamination by flushing of the air within the cab1.

In particular, as stated above, the process can provide the monitoring of a signal initiated by the occurrence of an access4of the cab1, for example the access door4or a window, as the cab1may effectively be contaminated upon entry through an open access4of air polluted with the spreading product. In relation toFIG. 5, the process provides a step C1wherein the occurrence of an access4of the cab1is detected, and then a consecutive step D wherein the flushing procedure is performed upon the detection.

To do so, the air conditioning system5includes various devices for monitoring such an occurrence signal. For example, the condition system5may include at least one air flow sensor24, pressure sensor25, and/or a door sensor implemented within the cab1. The air flow and/or pressure sensors24,25can be configured for monitoring the changes of air flow and/or pressure within the cab1due to a potential opening or closing of an access4of the cab1. At least one pressure sensor can also be configured for providing an opening signal and a closing signal of the access such that the flushing procedure is performed only upon a detection of the closing signal.

Moreover, the process can provide the monitoring of a signal initiated by a manual activation of an appropriate way by the operator in the cab1, for example a button or a switch on a control board within the cab. Thus, in relation toFIG. 5, the process provides a step C2wherein the actuation by the operator is detected, the step D of flushing procedure being performed upon the detection.

Generally, the process can provide for checking, during the monitoring steps C1, C2, the closing of all accesses4of the cab1before performing the step D or flushing procedure. Indeed, for performing the flushing procedure in the best conditions, it is necessary to stop at first potential entries of polluted air within the cab1, the stopping being in particular achieved through the total closing of accesses4of the cab.

In particular, in the case of an occurrence of an access4of the cab1, the process can provide the monitoring of consecutive opening and closing signals of the access, in particular by performing step C1upon detection of the opening signal and by monitoring the consecutive closing signal during this step C1, so as to perform the step D of flushing procedure only upon the detection of the closing signal.

Moreover, in the case of a manual actuation by the operator, the process can provide for checking the closing of all accesses4of the cab1and, in the case when at least one of the accesses is open, for alerting the operator of such opening, for example through the displaying of an error message on the control board in the cab1.

Once all the above mentioned conditions are met, the process provides for performing the step D of flushing procedure. In particular, the process can provide for informing the operator that the flushing procedure is to be performed, in particular by actuating an indicator lighting button26on the control board or displaying an icon on a screen in the cab1.

During the step D, the flushing procedure may provide for operating the air conditioning system5to increase the flow of air supplied in the cab1by the blowing device10through the circuit9, so as to accelerate the evacuation of potentially polluted air within the cab1. In particular, the flushing procedure may provide for operating the blowing device10to supply the cab1with an air flow having a flow rate greater than 40 m3/h.

Moreover, to avoid recycling of potentially contaminated air coming from the interior of the cab1, the flushing procedure may provide, as represented inFIG. 6B, to balance the flow of air FEonly in the exterior branch9bof the circuit9by closing the recycling branch9a.

To do so, the process provides for using the recycling valve27located in the recycling branch9afor selectively opening and closing the recycling branch, the flushing procedure providing to operate the recycling valve for closing the recycling branch.

Besides, to increase the flow of air evacuated from the cab1, the flushing procedure provides to open an exhaust flap28located in a bottom wall or roof of the cab1, through which the flow of air can be guided to the exterior of the cab. At the end of the flushing procedure, the exhaust flap28is closed again, to restore the regular procedure conditions.

In particular, the process may provide for performing the step D of flushing procedure for a determined period of time before performing again the regular procedure, in particular by stopping the step D of flushing procedure after the expiry of the period of time and for relaunching step E for restoring such regular procedure upon the stopping. According to an exemplary embodiment, the determined period of time is fixed, in particular comprised between 120 s and 140 s, according to the total volume of the cab1and the flow rates of air flow evacuated from the cab.