Post-harvest processing device and method for plant products, comprising a storage unit and a processing device

Abstract

Post-harvest treatment device and method for plant products, assembly comprising a storage and a treatment device. The device is intended for the post-harvest treatment of plant products stored in a closed storage (1), the treatment device (3) comprising: - a nebulization machine (7) having a gas inlet (9) and a gas outlet (11), the gas outlet (11) being fluidly connected to the closed storage (1);- a suction line (13), comprising an upstream end (15) connected to the closed storage (1), a downstream end (17) connected to the gas inlet (9) of the nebulizer (7), and a cyclone (19) interposed between the upstream end (15) and the downstream end (17), the nebulizer (7) being configured to draw into the closed storage (1) through the suction line (13) a gas stream laden with solid and / or liquid particles and to discharge through the gas outlet (11) said gas stream laden with an aerosol of a liquid containing a biocidal and / or phytosanitary product; the cyclone (19) being configured to separate the solid and / or liquid particles from the aspirated gas stream. Figure for the abbreviation: 1;

Description

Title of the invention: Post-harvest processing device and method for plant products, comprising a storage unit and a processing device

[0001] The invention relates generally to the post-harvest treatment of plant products stored in a closed storage facility.

[0002] FR 2 791 910 Al and FR 2 938 458 Al both disclose a post-harvest treatment device for plant products by thermal fogging.

[0003] This device includes a nebulizing machine that forces into the storage a flow of air charged in an aerosol of a liquid containing a biocidal and / or phytosanitary product.

[0004] In other words, the treatment device is designed for the direct injection of an aerosol into the closed storage in which the plant products are located.

[0005] Due to the injection of the airflow into the storage, the latter is maintained at a pressure slightly higher than the external pressure.

[0006] This presents several disadvantages.

[0007] Aerosol leaks may occur outside the storage area. These leaks pose a danger to personnel when the treatment product exhibits a certain level of toxicity.

[0008] Furthermore, if the leak is in the upper part of the chamber, where the concentration of aerosols is normally highest, the loss of active material can be significant.

[0009] Furthermore, due to the slight pressure increase required to inject the gas stream into the closed storage tank, some coalescence of the aerosols may occur. This coalescence is undesirable, as it leads to an increase in the mass of the injected particles, which is detrimental to the diffusion of these particles through the storage tank.

[0010] To address the above problems, the closed storage unit can be equipped with an air extractor that draws air from inside the unit and expels it outside after purification. This maintains a slightly negative pressure inside the closed storage unit. The extracted air, containing the treatment product, is filtered through activated carbon to prevent the release of treatment product residues into the environment. This technical solution has the drawback that the activated carbon must be periodically changed or regenerated.

[0011] In this context, the invention aims to provide a post-harvest treatment device for plant products stored in a closed storage facility which does not have the above defects.

[0012] To this end, the invention relates, in a first aspect, to a post-harvest treatment device for plant products stored in closed storage, the treatment device comprising:

[0013] - a nebulizing machine having a gas inlet and a gas outlet, the outlet of gas being fluidly connected to the closed storage;

[0014] - a suction line, comprising an upstream end connected to the storage closed, with one downstream end connected to the gas inlet of the nebulizing machine, and a cyclone interposed between the upstream and downstream ends,

[0015] the nebulizing machine being configured to draw into the closed storage through the suction line a flow of gas charged with solid and / or liquid particles and to expel through the gas outlet said flow of gas charged with an aerosol of a liquid containing a biocidal and / or phytosanitary product;

[0016] the cyclone being configured to separate solid and / or liquid particles from the aspirated gas stream.

[0017] Thus, the aerosol-laden gas flow injected into the storage tank is first drawn into the tank, and therefore originates from the tank itself. The gas circulates in a closed loop, the quantity of air drawn out of the tank being substantially equal to the quantity of air forced back into the tank. It is therefore possible to maintain the tank at substantially the same pressure as the outside atmosphere, so that neither air nor gas escapes in the event of a leak.

[0018] The gas drawn into the closed storage unit is laden with solid and / or liquid particles. The solid particles are, for example, dust generated by the plant products stored in the unit. The liquid particles come from the injected aerosol, or from the humidity generated by the plant products inside the storage unit.

[0019] The cyclone makes it possible to separate the solid and / or liquid particles from the aspirated gas stream, and therefore makes it possible to recycle in the nebulization machine only a practically clean gas, free of particles.

[0020] The fouling of the processing machine is thus limited.

[0021] Furthermore, there is no release of treatment product outside the closed storage, the treatment product being trapped by the cyclone.

[0022] Separation by a cyclone is well suited to treat the gas flow rate generally required for the operation of the nebulizing machine. It also makes it possible to obtain a sufficiently high purification yield for the desired application.

[0023] The treatment device may also have one or more of the following characteristics, considered individually or in all technically possible combinations:

[0024] - the cyclone includes an inlet for the gas flow laden with solid particles and / or liquids, a first outlet for the purified gas stream and a second outlet for the particles separated from the gas stream, the second outlet being connected to a closed container;

[0025] - the particles separated from the gas flow flow by gravity from the second outlet in the closed container;

[0026] - the nebulizing machine is a thermal nebulizing machine, comprising a gas flow heating;

[0027] - the liquid comprises an organic solvent of a structure comprising only atoms of C, H and O.

[0028] According to a second aspect, the invention relates to an assembly comprising a closed storage and a treatment device having the above characteristics, the gas outlet of the nebulizing machine being fluidly connected to the closed storage, the upstream end of the suction line being connected to the closed storage.

[0029] The processing unit may also have one or more of the following characteristics, considered individually or in all technically possible combinations:

[0030] - the upstream end of the suction line opens into the closed storage, at a level less than one meter above the ground;

[0031] - the nebulizing machine is configured to draw air from inside the storage closed and to pump back inside the closed storage (the same gas flow rate.

[0032] According to a third aspect, the invention relates to a post-harvest treatment process for plant products stored in closed storage, the treatment process comprising: - the aspiration into the closed storage of a gas stream laden with solid and / or liquid particles; - the separation in a cyclone of solid and / or liquid particles from the aspirated gas stream; - the discharge into the closed storage of said gas stream charged in an aerosol form with a liquid containing a biocidal and / or phytosanitary product.

[0033] Other features and advantages of the invention will become apparent from the detailed description given below, by way of example and not limitation, with reference to the accompanying figures, among which: - [Fig.1] The [Fig.1] is a simplified schematic representation of an assembly comprising a closed storage in which plant products are stored and a processing device according to the invention; - [Fig.2] The [Fig.2] is a simplified schematic representation of the cyclone of the nebulizing machine of the device of the [Fig.1], mounted on a closed container.

[0034] The assembly shown in [Fig.1] comprises a closed storage 1 intended for the storage of plant products, and a post-harvest treatment device 3 for the plant products stored in the closed storage 1.

[0035] Storage 1 is substantially airtight. It is closed in the sense that exchanges between the internal atmosphere of the storage and the outside, in particular gas exchanges, are reduced, so as to guarantee the proper preservation of the stored plant products.

[0036] Storage 1 is for example a cold room, a greenhouse or any premises intended for the storage of plant products.

[0037] Storage 1 is typically a large volume storage, preferably having a volume greater than 200 m3, even more preferably greater than 500 m3, and typically having a volume greater than 1000 m3.

[0038] Typically, plant products 5 are stored inside storage 1. Plant products 5 are, for example, cereals, or fruits, or vegetables such as potatoes.

[0039] In the closed storage unit 1, the plant products 5 are stored under an air atmosphere. Alternatively, they are stored under a modified atmosphere. For example, the gas filling the closed storage unit 1 is a neutral gas such as nitrogen, or oxygen-depleted air, or any other suitable gas.

[0040] The treatment device 3 includes a nebulizing machine 7 having a gas inlet 9 and a gas outlet 11, the gas outlet 11 being fluidly connected to the closed storage 1.

[0041] The treatment device 3 further includes a suction line 13, comprising an upstream end 15 connected to the closed storage 1 and a downstream end 17 connected to the gas inlet 9 of the nebulizing machine.

[0042] Thus, the nebulizing machine 3 draws in the gas contained in the closed storage 1, and pumps it back into the closed storage 1, in a closed circuit.

[0043] The nebulizing machine 7 is configured to draw into the closed storage 1 through the suction line 13 a flow of gas charged with solid and / or liquid particles.

[0044] A cyclone 19 is intercalated in the suction line 13 to separate solid and / or liquid particles from the aspirated gas stream.

[0045] The nebulizing machine 7 is configured to expel through outlet 11 said gas stream charged in an aerosol of a liquid containing a biocide and / or phytosanitary product.

[0046] The gas outlet 11 of the nebulizing machine 7 is connected to the closed storage 1 by a discharge line 21.

[0047] The nebulizing machine 7 is of any suitable type.

[0048] For example, the nebulizing machine is a hot nebulizing machine, that is to say a thermonebulizing machine.

[0049] Such a thermal fogging machine is described in patent applications published under numbers FR 2 938 458 A1 or FR 2 791 910 A1

[0050] Such a thermonebulizing machine 7 comprises a blower 23 whose suction is fluidly connected to the gas inlet 9. The blower 23 discharges the gas into an outlet duct 25 in which a heating element 27 is housed.

[0051] The heating element 27 is of any suitable type. For example, it is an electric heating element.

[0052] The liquid containing the biocidal and / or phytosanitary product is injected into the outlet conduit 25 downstream of the heating element 27.

[0053] It is drawn into a liquid reservoir 29 by a pump 31, and discharged by the pump 31 into the outlet conduit 25.

[0054] The liquid is dispersed in the hot gas circulating in the outlet duct 25 in the form of an aerosol.

[0055] The gas outlet 11 is placed at the end of the outlet conduit 25.

[0056] Alternatively, the nebulizing machine 7 operates cold, i.e. without a heating element.

[0057] The liquid containing the biocidal and / or phytosanitary product is dispersed in the gas stream at substantially the temperature prevailing inside the closed storage 1.

[0058] According to another variant, only part of the gas flow from the closed storage is heated and another part remains at the internal temperature of the storage.

[0059] The biocidal and / or phytosanitary product is, for example, chosen from the following list: essential oil; terpene; saturated or unsaturated C6 to C10 alcohols, such as octanol, 2-ethylhexanol; volatile synthetic products such as hexanal, 1,4-dimethylnaphthalene and 3-decene-2-one; liquid organic acids with a high boiling point such as pelargonic acid and parabenic acid; esters with biocidal activities such as isoamyl isovalerate; synthetic fungicidal, antioxidant or other molecules authorized for post-harvest treatment such as pyrimethanyl, imazalil, thiabendazole, orthophenylphenol; DPA (diphenylamine) and ethoxyquine are antioxidants, and CIPC (isopropyl3 chlorophenylcarbamate) is an anti-sprouting agent for potatoes.

[0060] The essential oil is, for example, chosen from the group consisting of mint oil, clove oil, rose oil, thyme oil, oregano oil, eucalyptus oil, pine oil, and cinnamon oil. Alternatively, the liquid comprises one of the constituents of these oils, chosen from the group consisting of L-carvone, eugenol, geraniol, thymol, carvacrol, eucalyptol, pinene, and cinnamaldehyde.

[0061] Typically, the liquid comprises only the biocidal and / or phytosanitary product(s), without solvent or adjuvant. Alternatively, the liquid comprises an aqueous or organic solvent in which the product(s) and possibly one or more adjuvants are dissolved.

[0062] The biocidal and / or phytosanitary product is typically a solid product dissolved in cold or hot solvent droplets. The solvents used preferably have a high boiling point. For example, the solvent is chosen from monopropylene glycol, dipropylene glycol, or various terpenes.

[0063] In a conventional manner, the cyclone 19 is configured to separate particles from the gas stream by centrifugal effect.

[0064] The cyclone 19 includes an inlet 33 for the gas stream loaded with solid and / or liquid particles, a first outlet 35 for the purified gas stream, and a second outlet 37 for the particles separated from the gas stream.

[0065] The inlet 33 is fluidly connected to the upstream end 15 of the suction line. The first outlet 35 is fluidly connected to the downstream end 17 of the suction line. The second outlet 37, as seen in [Fig. 2], is connected to a closed container 39.

[0066] The closed container 39 is intended to collect solid and / or liquid particles.

[0067] The particles separated from the gas flow flow by gravity from the second outlet 37 into the closed container 39.

[0068] As can be seen in particular in [Fig. 2], the cyclone 19 delimits an internal chamber 41 of generally frustoconical shape and vertical axis. The inlet 33 directs the gas tangentially to the upper part of the chamber 4L. The first outlet 35 is located along the vertical axis of the chamber 41, in the upper part of this chamber. The second outlet 37 is located at the bottom of the chamber 4L.

[0069] The container 39 is, for example, a can closed by a removable lid 43. The cyclone 19 is mounted on the lid 43. The second outlet 37 communicates with the internal volume of the container 39 through an opening provided in the center of the lid 43.

[0070] Cyclone 19 blocks particles larger than 50 microns and therefore does not stop aerosol droplets which are smaller.

[0071] Advantageously, the liquid comprises an organic solvent of structure containing only carbon atoms C, hydrogen H and oxygen O.

[0072] For example, the organic solvent is chosen from the following list: hydrocarbons, alcohols, glycols, esters such as butyl acetate or ethyl lactate, terpenes.

[0073] Cyclone 19 allows the particles to be separated from the gas stream coming from the closed storage 1. On the other hand, it does not allow the vapors of organic solvents to be stopped, which will pass through cyclone 19 and the nebulizing machine 3.

[0074] The solvents used in the present invention are typically heavy solvents, the concentration of which in the gas stream does not reach the flammability threshold, i.e. the critical concentration to be ignited in the heating element 27. The solvents will pass through the nebulizing machine without igniting.

[0075] If, in a very unlikely event, the concentration of organic solvents was above the flammability threshold, the combustion of the organic solvents retained here would produce only water and carbon dioxide CO2, which can be recycled in storage without compromising the preservation of plant products.

[0076] Advantageously, the suction line 13 opens into the closed storage 1 at a level less than 1 m above the ground.

[0077] In other words, the upstream end 15 of the suction line is located relative to the ground at a height of less than 1 m.

[0078] Hot aerosols do tend to remain at the top of the storage tank. Drawing from the bottom of the tank offers two advantages. The first is to draw in gas where the concentration of microdroplets is very low, thus reducing the risk of significant losses in the cyclone. The second is to create a weak, downward flow of gas, which reduces the inhomogeneity of the microdroplet concentration and thus increases the performance of the treatment.

[0079] The invention also relates to a post-harvest treatment method for plant products stored in closed storage.

[0080] The process is particularly suitable for implementation using the device and assembly described above. Conversely, the device and assembly described above are designed for implementation of the treatment process.

[0081] The closed storage is typically that described above.

[0082] The plant products are as described above.

[0083] The treatment process comprises:

[0084] - the aspiration into the closed storage 1 of a gas stream laden with solid particles and / or liquids;

[0085] - the separation in a cyclone 19 of solid and / or liquid particles from the gas stream aspirated;

[0086] - the discharge into the closed storage 1 of said gas stream charged in an aerosol of a liquid containing a biocidal and / or phytosanitary product.

[0087] Suction is carried out via the suction line 13 described above. The cyclone 19 is intercalated on this suction line 13.

[0088] The cyclone 13 is of the type described above. Its second outlet is connected to a closed container 39, of the type described above.

[0089] After passing through cyclone 19, the gas stream is aerosolized in a nebulizing machine 7 of the type described above.

Claims

Demands

1. Post-harvest treatment device for plant products stored in a closed storage (1), the treatment device (3) comprising: - a nebulizing machine (7) having a gas inlet (9) and a gas outlet (11), the gas outlet (11) being fluidly connected to the closed storage (1); - a suction line (13), comprising an upstream end (15) connected to the closed storage (1), a downstream end (17) connected to the gas inlet (9) of the nebulizing machine (7), and a cyclone (19) interposed between the upstream end (15) and the downstream end (17), the nebulizing machine (7) being configured to draw into the closed storage (1) through the suction line (13) a flow of gas charged with solid and / or liquid particles and to expel through the gas outlet (11) said flow of gas charged with an aerosol of a liquid containing a biocidal and / or phytosanitary product;the cyclone (19) being configured to separate solid and / or liquid particles from the aspirated gas stream.;

2. A treatment device according to claim 1, wherein the cyclone (19) comprises an inlet (33) for the gas stream laden with solid and / or liquid particles, a first outlet (35) for the purified gas stream and a second outlet (37) for the particles separated from the gas stream, the second outlet (37) being connected to a closed container (39).

3. Processing device according to claim 2, wherein the particles separated from the gas stream flow by gravity from the second outlet (37) into the closed container (39).

4. Processing device according to any one of claims 1 to 3, wherein the nebulizing machine (7) is a thermal nebulizing machine, comprising a gas flow heater (27).

5. Processing device according to any one of claims 1 to 4, wherein the liquid comprises an organic solvent of structure comprising only C, H and O atoms.

6. Assembly comprising a closed storage unit (1) and a processing device (3) according to any one of claims 1 to 5, the gas outlet (11) of the nebulizing machine (7) being connected

7.

8.

9. fluidly to the closed storage (1), the upstream end (15) of the suction line (13) being connected to the closed storage (1). Assembly according to claim 6, wherein the upstream end (15) of the suction line (13) opens into the closed storage (1), at a level less than one meter above the ground. Assembly according to claim 6 or 7, wherein the nebulizing machine (7) is configured to draw into the closed storage (1) and to discharge into the closed storage (1) the same flow rate of gas. Post-harvest processing method for plant products (5) stored in closed storage (1), the processing method comprising: - the aspiration into the closed storage (1) of a gas stream charged with solid and / or liquid particles; - the separation in a cyclone (19) of the solid and / or liquid particles of the aspirated gas stream; - the discharge into the closed storage (1) of said gas flow charged in an aerosol with a liquid containing a biocidal and / or phytosanitary product.

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