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

Abstract

The invention relates to a processing device for the post-harvest processing of plant products stored in a closed storage unit (1), the processing device (3) comprising: - a fogging machine (7) having a gas inlet (9) and a gas outlet (11), the gas outlet (11) being fluidically connected to the closed storage unit (1); - a suction line (13), comprising an upstream end (15) connected to the closed storage unit (1), a downstream end (17) connected to the gas inlet (9) of the fogging machine (7), and a cyclone (19) positioned between the upstream end (15) and the downstream end (17), the fogging machine (7) being configured to draw from the closed storage unit (1), through the suction line (13), a stream of gas laden with solid and / or liquid particles and to deliver, via the gas outlet (11), the stream of gas 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 drawn gas stream.

Description

[0001] TITLE: Post-harvest processing device and method for plant products, comprising a storage unit and a processing device

[0002] The invention relates generally to the post-harvest treatment of plant products stored in a closed storage facility.

[0003] FR 2 791 910 A1 and FR 2 938 458 A1 both disclose a post-harvest treatment device for plant products by thermal fogging.

[0004] This device includes a nebulization machine that forces a stream of air charged with an aerosol of a liquid containing a biocidal and / or phytosanitary product into the storage area.

[0005] In other words, the treatment device is designed for the direct injection of an aerosol into the closed storage area containing the plant products.

[0006] Due to the injection of airflow into the storage tank, it is maintained at a pressure slightly higher than the outside pressure.

[0007] This has several drawbacks.

[0008] Aerosol leaks from storage can occur. These leaks pose a danger to personnel when the treatment product has a certain level of toxicity.

[0009] 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.

[0010] Furthermore, due to the slight pressure increase required to inject the gas stream into the closed storage facility, some aerosol coalescence may occur. This coalescence is undesirable, as it leads to an increase in the mass of the injected particles, which is detrimental to their diffusion throughout the storage facility.

[0011] To address the above problems, it is possible to equip the closed storage unit 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 replaced or regenerated. In this context, the invention aims to provide a post-harvest treatment device for plant products stored in a closed storage unit that does not present the above drawbacks.

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

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

[0014] - a suction line, comprising an upstream end connected to the closed storage, a downstream end connected to the gas inlet of the nebulizing machine, and a cyclone interposed between the upstream and downstream ends, 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; the cyclone being configured to separate the solid and / or liquid particles from the aspirated gas flow.

[0015] Thus, the aerosol-laden gas 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, with the amount of air drawn out of the tank being approximately equal to the amount of air forced back into the tank. This allows the tank to be maintained at roughly the same pressure as the outside atmosphere, preventing both air ingress and gas escaping in the event of a leak.

[0016] The gas drawn into the closed storage unit is laden with solid and / or liquid particles. Solid particles include, for example, dust generated by the plant products stored there. Liquid particles originate from injected aerosol or from moisture generated by the plant products inside the storage unit.

[0017] The cyclone allows the solid and / or liquid particles to be separated from the aspirated gas stream, and therefore allows only a practically clean gas, free of particles, to be recycled in the nebulization machine.

[0018] This limits the fouling of the processing machine.

[0019] Furthermore, there is no release of treatment product outside the closed storage area, as the treatment product is trapped by the cyclone.

[0020] Cyclone separation is well-suited for handling the gas flow typically required for nebulization machine operation. It also provides a sufficiently high purification yield for the intended application.

[0021] The treatment device may also have one or more of the following characteristics, considered individually or in all technically possible combinations:

[0022] - the cyclone includes an inlet for the gas stream loaded with solid and / or liquid particles, 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;

[0023] - the particles separated from the gas flow flow by gravity from the second outlet into the closed container;

[0024] - the nebulization machine is a thermonebulization machine, comprising a heating gas flow;

[0025] - the liquid comprises an organic solvent with a structure consisting only of C, H and O atoms.

[0026] 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.

[0027] The processing system may also exhibit one or more of the following characteristics, considered individually or in all technically possible combinations:

[0028] - the upstream end of the suction line opens into the closed storage area, at a level less than one meter above the ground;

[0029] - the nebulization machine is configured to draw in and expel gas into the closed storage area (the same gas flow rate).

[0030] 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:

[0031] - the aspiration into the closed storage of a gas stream laden with solid and / or liquid particles;

[0032] - the separation in a cyclone of solid and / or liquid particles from the aspirated gas stream;

[0033] - 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.

[0034] 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 attached figures, among which: - Figure 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;

[0035] - Figure 2 is a simplified schematic representation of the cyclone of the nebulizing machine of the device in Figure 1, mounted on a closed container.

[0036] The assembly shown in Figure 1 includes 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.

[0037] Storage unit 1 is essentially airtight. It is closed in the sense that exchanges between the internal atmosphere of the storage unit and the outside, particularly gas exchanges, are reduced, so as to guarantee the proper preservation of the stored plant products.

[0038] Storage 1 is, for example, a cold room, a greenhouse, or any premises intended for the storage of plant products.

[0039] Storage 1 is typically a large-volume storage facility, preferably with a volume greater than 200 m³ 3 preferably above 500 m 3 , and typically having a volume greater than 1000 m 3 .

[0040] Typically, 5 plant products are stored inside storage 1. 5 plant products are, for example, cereals, or fruits, or vegetables such as potatoes.

[0041] In closed storage 1, the plant products 5 are stored under an air atmosphere. Alternatively, they are stored under a modified atmosphere. For example, the gas filling closed storage 1 is a neutral gas such as nitrogen, or oxygen-depleted air, or any other suitable gas.

[0042] 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.

[0043] The treatment device 3 also 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.

[0044] Thus, the nebulization machine 3 draws the gas contained in the closed storage 1, and pumps it back into the closed storage 1, in a closed circuit.

[0045] 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.

[0046] A cyclone 19 is inserted in the suction line 13 to separate solid and / or liquid particles from the aspirated gas stream. The nebulizer 7 is configured to discharge said gas stream, now charged as an aerosol of a liquid containing a biocide and / or phytosanitary product, through outlet 11.

[0047] The gas outlet 11 of the nebulizing machine 7 is connected to the closed storage 1 by a discharge line 21.

[0048] The 7 nebulizing machine is suitable for all types.

[0049] For example, the nebulizing machine is a hot nebulizing machine, that is to say a thermal nebulizing machine.

[0050] Such a thermonebulization machine is described in patent applications published under numbers FR 2 938 458 A1 or FR 2 791 910 A1.

[0051] Such a thermonebulizing machine 7 includes a blower 23 whose suction is fluidly connected to the gas inlet 9. The blower 23 forces the gas into an outlet duct 25 in which a heating element 27 is housed.

[0052] The heating element 27 is suitable for any type. For example, it is an electric heating element.

[0053] The liquid containing the biocide and / or phytosanitary product is injected into the outlet duct 25 downstream of the heating element 27.

[0054] It is drawn into a liquid reservoir 29 by a pump 31, and discharged by the pump 31 into the outlet conduit 25.

[0055] The liquid is dispersed in the hot gas circulating in the outlet duct 25 in the form of an aerosol.

[0056] The gas outlet 11 is located at the end of the outlet duct 25.

[0057] Alternatively, the nebulizing machine 7 operates cold, i.e. without a heating element.

[0058] 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.

[0059] 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.

[0060] The biocidal and / or phytosanitary product is chosen for example 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 antioxidant, and CIPC (isopropyl 3-chlorophenylcarbamate) anti-sprouting agent for potatoes.

[0061] The essential oil is, for example, chosen from the group consisting of peppermint oil, clove oil, rose oil, thyme oil, oregano oil, eucalyptus oil, pine oil, and cinnamon oil. Alternatively, the liquid contains one of the constituents of these oils, chosen from the group consisting of L-carvone, eugenol, geraniol, thymol, carvacrol, eucalyptol, pinene, and cinnamaldehyde.

[0062] Typically, the liquid contains only the biocidal and / or plant protection product(s), without solvent or adjuvant. Alternatively, the liquid contains an aqueous or organic solvent in which the product(s) and possibly one or more adjuvants are dissolved.

[0063] The biocidal and / or phytosanitary product is typically a solid product dissolved in the solvent droplets, either hot or cold. The solvents used are preferably those with a high boiling point. For example, the solvent is chosen from among monopropylene glycol, dipropylene glycol, or various terpenes.

[0064] In a conventional manner, cyclone 19 is configured to separate particles from the gas stream by centrifugal effect.

[0065] 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.

[0066] 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 shown in Figure 2, is connected to a closed container 39.

[0067] The closed container 39 is intended to collect solid and / or liquid particles.

[0068] The particles separated from the gas stream flow by gravity from the second outlet 37 into the closed container 39.

[0069] As can be seen in particular in Figure 2, the cyclone 19 delimits an internal chamber 41, generally frustoconical in shape and with a vertical axis. The inlet 33 directs the gas tangentially to the upper part of the chamber 41. The first outlet 35 is located along the vertical axis of the chamber 41, at its upper part. The second outlet 37 is located at the bottom of the chamber 41.

[0070] Container 39 is, for example, a can closed by a removable lid 43. Cyclone 19 is mounted on the lid 43. The second outlet 37 communicates with the internal volume of container 39 through an opening in the center of the lid 43. 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 with a structure containing only carbon atoms (C), hydrogen atoms (H), and oxygen atoms (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. However, it does not allow the vapors of organic solvents to be stopped, which will pass through cyclone 19 and the nebulization 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 were 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 tend to remain at the top of the storage tank. Drawing from the bottom of the tank offers two advantages. First, it draws gas where the concentration of microdroplets is very low, thus reducing the risk of significant losses in the cyclone. Second, it creates a low-flow gas current from top to bottom, which reduces the inhomogeneity of the microdroplet concentration and thus increases the treatment's efficiency.

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

[0080] The process is particularly well-suited for implementation using the device and assembly described above. Conversely, the device and assembly described above are designed for implementing the treatment process.

[0081] Closed storage is typically that described above.

[0082] The plant products are as described above. The processing method includes:

[0083] - the aspiration into the closed storage 1 of a gas stream laden with solid and / or liquid particles;

[0084] - the separation in a cyclone 19 of the solid and / or liquid particles from the aspirated gas stream;

[0085] - the discharge into the closed storage 1 of said gas flow charged in an aerosol of a liquid containing a biocidal and / or phytosanitary product.

[0086] Suction is carried out via the suction line 13 described above. The cyclone 19 is inserted on this suction line 13. The cyclone 13 is of the type described above. Its second outlet is connected to a closed container 39, of the type described above.

[0087] After passing through cyclone 19, the gas stream is aerosolized in a nebulization machine 7 of the type described above.

Claims

DEMANDS 1. An assembly comprising an enclosed storage unit (1) in which plant products are stored and a post-harvest processing device for the plant products stored in the enclosed storage unit (1), the processing 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 gas stream charged with solid and / or liquid particles and to discharge through the gas outlet (11) said gas stream charged with an aerosol of a liquid containing a biocide and / or phytosanitary product; the cyclone (19) being configured to separate the solid and / or liquid particles from the aspirated gas stream.

2. Assembly 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. Assembly 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. Assembly according to any one of claims 1 to 3, wherein the nebulizing machine (7) is a thermonebulizing machine, comprising a gas flow heater (27).

5. Assembly 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 according to any one of claims 1 to 5, 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.

7. Assembly according to any one of claims 1 to 6, wherein the nebulizing machine (7) is configured to draw into the closed storage (1) and to expel into the closed storage (1) the same flow rate of gas.

8. 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 laden with solid and / or liquid particles; - the separation in a cyclone (19) of the solid and / or liquid particles from 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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