Microwave radiation heat treatment system having a switching unit

Abstract

The present invention relates to a treatment system having first and second reaction chambers (1, 1'), a generator (2), and a switching unit (4) that can be moved between first and second end positions such that: - in the first end position, the first chamber (1) is connected to the generator (2) via the switching unit (4), and the second chamber (1') is disconnected from the generator (2), and - in the second end position, the second chamber (1') is connected to the generator (2) via the switching unit (4), and the first chamber (1) is disconnected from the generator (2).

Description

[0001] Description

[0002] Title: MICROWAVE RADIATION HEAT TREATMENT SYSTEM INCLUDING A SWITCHING UNIT

[0003] FIELD OF THE INVENTION

[0004] The present invention relates to the general technical field of systems for treating plant biomass of any plant species known to those skilled in the art, for example parts of vines.

[0005] The biomass to be treated can be dry or wet, and its treatment can be carried out in the presence (or not) of an aqueous solvent.

[0006] Such a treatment device allows the extraction of metabolites from plant biomass, said metabolites being able to be polyphenols or any other type of secondary metabolites known to those skilled in the art.

[0007] The metabolites thus extracted can be used in different application fields, such as biocontrol applications or cosmetic applications.

[0008] In the following, the device according to the invention will be described with reference to the treatment of a dry plant biomass rich in polyphenols (such as parts of vines) in the presence of an aqueous solvent, it being understood by those skilled in the art that the device according to the invention can be used for the treatment of any type of plant biomass - dry or wet - in the presence or absence of one (or more) aqueous solvent(s). STATE OF THE ART

[0009] 1. Presentation

[0010] Plant biomass extracts rich in polyphenols are known to those skilled in the art.

[0011] Many studies have focused on the extraction of biomass to obtain an extract rich in polyphenols, all of which have several drawbacks regarding the economic viability of the processes, such as low yields or very long extraction times, or limiting their post-extraction use, and in particular the use of toxic organic solvents.

[0012] Document WO 2018 / 115296 describes a process for preparing an extract of dry plant biomass, rich in polyphenols, comprising: a step of extracting the dry biomass by bringing it into contact with an aqueous solvent, and a step of recovering the aqueous phase enriched in polyphenols.

[0013] During the extraction step, the plant biomass / aqueous solvent mixture is treated, at a pressure of between 50 and 950 mbar (5,000 to 95,000 Pa), by applying to the mixture: electromagnetic waves with a frequency of between 10 MHz and 100 GHz, preferably between 433 MHz and 30 GHz, and even more preferably between 915 MHz and 28 GHz, and stirring the mixture.

[0014] The present invention aims to propose a thermal treatment system allowing the implementation of the method according to WO 2018 / 115296. In particular, the present invention relates to a system for treating a product for the extraction of a substance of interest, the treatment system being configured to: stir the product, and - apply to the product electromagnetic waves of a frequency between 10 MHz and 100 GHz, preferably between 433 MHz and 30 GHz, and even more preferably between 915 MHz and 28 GHz.

[0015] - 2. Problems associated with the use of electromagnetic waves

[0016] 2.1 Minimization of electromagnetic leakage levels

[0017] The use of electromagnetic waves for industrial, scientific and medical applications is subject to compliance with several standards for the protection of people and the protection of communications networks: standard EN 50413 for the exposure of people, standard EN 50499 for the exposure of workers, standard EN 55011 for the protection of telecommunications networks.

[0018] The use, on an industrial scale, of electromagnetic waves with a frequency equal to 915 MHz requires in particular compliance with standard NE 55011. This stipulates that the electromagnetic radiation emitted towards the outside, by a system generating electromagnetic waves with a frequency equal to 915 MHz, must be lower than a threshold value of -40 dB microvolt per meter, at 30 m from said system.

[0019] This helps to avoid disruptions to telecommunications networks.

[0020] Any exceeding of this threshold value may be sanctioned, without notice, by the immediate shutdown of the system deemed to be faulty.

[0021] An aim of the present invention is to propose a system for heat treatment using electromagnetic waves which makes it possible not to exceed the levels of electromagnetic leakage imposed by standard EN 55011. 2.2 Improvement of productivity

[0022] Given the restrictions linked to the NE 55011 standard (leakage radiation at 30 m less than 40 dB mV / ), the industrial use of devices for processing electromagnetic waves with a frequency equal to 915 MHz generally remains limited to the processing of products in batches (or "batches", according to the terminology used in the field of industrial processes), provided that all protections have been implemented to avoid exceeding the imposed electromagnetic leakage levels.

[0023] As illustrated in Figure 1, such a device is composed of: an enclosure 1 containing the product 2 to be treated, a stirring unit housed in the enclosure, and a waveguide 3, connected between the enclosure 1 and a generator 4 of electromagnetic waves, to transmit the electromagnetic waves generated by the generator 4 to the enclosure 1.

[0024] A common disadvantage of the various batch product processing devices is that their productivity is limited due to the fact that the batch processing time is quite long. Indeed, at each new use, it is necessary to carry out: o the loading of the reaction chamber 1, o the generation of a depression in the chamber 1, o the heating by electromagnetic waves of the product placed in the chamber 1, o the cooling and atmospheric pressure of the chamber 1 for the recovery of the treated product 2 and the cleaning of the chamber 1.

[0025] An object of the present invention is to provide a system for processing a product in batches in which productivity is improved. ABSTRACT

[0026] To this end, the invention proposes a system for treating plant biomass, the treatment system comprising:

[0027] A first and a second enclosure each intended to contain the plant biomass to be treated, each of the first and second enclosures comprising a lower partition, an upper partition and at least one lateral partition extending between the upper and lower partitions, the upper partition including a through inlet, a generator for the production of electromagnetic waves, the generator comprising a protective casing, at least one source of electromagnetic waves housed in the protective casing, and an outlet opening provided in an upper plate of the protective casing, first and second mixing units contained respectively in the first and second enclosures, characterized in that the treatment system further comprises a switching unit including: a tubular waveguide for the circulation of electromagnetic waves between the generator and the first and second enclosures,and first and second connection cells arranged at a respective end of the waveguide, said switching unit being movable between: a first extreme position in which the first connection cell is connected to the inlet of the first enclosure and the second connection cell is connected to the outlet of the generator so that the electromagnetic waves produced by the generator are transmitted to the first enclosure via the switching unit, and a second extreme position in which the first cell is connected to the outlet of the generator and the second connection cell is connected to the inlet of the second enclosure so that the electromagnetic waves produced by the generator are transmitted to the second enclosure via the switching unit. In the context of the present invention, the term "connected to" is understood to mean:a first element directly connected to a second element, or indirectly connected to the second element, in particular by means of a third element arranged between the first and second elements.,

[0028] Preferred, but non-limiting aspects of the present invention are as follows: the treatment system may further comprise a metal plate including aligned first, second and third through-lights of identical dimensions, the distance between the centers of the first and second through-lights being equal to the distance between the centers of the second and third through-lights: o the first light being connected to the inlet of the first enclosure, o the second light being connected to the outlet opening of the generator, and o the third light being connected to the inlet of the second enclosure, the switching unit being in contact with the metal plate in the first and second extreme positions;each of the first and second connection cells may comprise a curved metal frame in a rectangular loop, said frame including an electromagnetic wave entry / exit slot, the dimensions of said frame being determined so that the electromagnetic waves entering the metal frame at the entry / exit slot, exit said metal frame in phase opposition at the entry / exit slot;the frame may comprise: o an external panel extending perpendicular to the metal plate, o an internal panel parallel to the external panel, the distance between the metal plate and the edge of the internal panel closest to the metal plate being non-zero when the switching unit is in the first or second extreme position, o an upper panel between the external and internal panels, the edges of the upper panel being connected to the edges of the external and internal panels furthest from the metal plate, and o a lower panel parallel to the upper panel, the lower panel extending between the external and internal panels and including:;

[0029] ■ a connecting edge connected to the edge of the internal panel closest to the metal plate,

[0030] ■ a free edge opposite the connecting edge, such that the lower face extends opposite the metal plate, at a non-zero distance from said metal plate when the switching unit is in the first or second extreme position, said lower face not being in contact with either the metal plate or the external face; each face is of rectangular overall shape, the sum of the widths: o of the external face, o of the upper face, o of the internal face, and o of the lower face being equal to a multiple of the wavelength of the electromagnetic waves plus a quarter of the wavelength of said electromagnetic waves; the thickness of the faces may be substantially equal to the thickness of the walls of the waveguide;each of the first and second connection cells may comprise a central channel whose dimensions are identical to the dimensions of the first, second and third through-lights, the center distance between the first and second connection cells being equal to the distance separating the centers of the first and second through-lights; the processing system may further comprise means for moving the switching unit between the first and second extreme positions, said moving means being configured to implement the following operations successively, when the switching unit is in the first extreme position: o move the switching unit in vertical translation so as to:;

[0031] ■ dissociate the first connection cell from the inlet of the first enclosure, and ■ dissociate the second connection cell from the outlet opening of the generator, o move the switching unit in horizontal translation so as to:

[0032] ■ position the first connection cell to the right of the generator output opening, and

[0033] ■ position the second connection cell in line with the inlet of the second enclosure, o move the switching unit in vertical translation so as to:

[0034] ■ connect the first connection cell to the generator output opening, and

[0035] ■ connecting the second connection cell to the inlet of the first enclosure; the switching unit may further comprise at least one sensor for detecting whether the switching unit is in the first extreme position or the second extreme position, the generator being able to be activated for the production of electromagnetic waves only if said and at least one sensor has detected that the switching unit is in the first extreme position or the second extreme position.

[0036] DETAILED DESCRIPTION OF THE INVENTION

[0037] An example of a processing system will now be described with reference to the figures. In these different figures, equivalent elements are designated by the same numerical reference.

[0038] 1. General information

[0039] The treatment device described below allows the preparation of an extract rich in metabolites (polyphenols and / or other secondary metabolite(s)) by extraction of a dry (or wet) biomass with (or without) an aqueous solvent.

[0040] According to the invention, the term "aqueous solvent" means water or an aliphatic alcohol / water mixture, in particular ethanol / water. The plant biomass may, for example, be a biomass containing polyphenols, in particular trans-resveratrol, trans-s-viniferin, trans-piceatannol and trans-vitisin. The person skilled in the art is familiar with this biomass originating from plants known to contain these polyphenols, used alone or in mixtures, generally dicotyledonous plants such as vines, tea or even Japanese knotweed, more particularly vines.

[0041] When the biomass is dry, that is to say obtained by drying the aforementioned plants, it may consist of dry parts of plants of the genus Vitis, in particular Vitis vinifera Vitis labrusca, Vitis riparia, Vitis rupestris, Vitis berlandieri, Vitis amurensis, Vitis coignetiae, Vitis vulpina, Vitis acerifolia, Vitis aestivalis, Vitis rotundifolia and more particularly Vitis vinifera. According to an advantageous embodiment of the invention, the dry biomass comprises or consists of vine shoots.

[0042] Alternatively, the biomass can be wet. In this case, the water molecules contained in the biomass can eliminate the need for an aqueous solvent.

[0043] This device allows the implementation of a process for extracting metabolites such as polyphenols.

[0044] This process is characterized by the combination of at least two constraints applied to plant biomass (dry or wet) in the presence (or not) of an aqueous solvent:

[0045] (i) electromagnetic waves with a frequency between 10 MHz and 100 GHz, preferably between 433 MHz and 30 GHz, and even more preferably between 915 MHz and 28 GHz, and

[0046] (ii) brewing, and / or

[0047] (iii) a pressure of 50 to 950 mbar.

[0048] In the following, the device according to the invention will be described with reference to the treatment of a mixture composed of a dry biomass and an aqueous solvent, it being understood by those skilled in the art that this device can be used with other types of products. 2. Treatment system

[0049] Referring to Figure 2, an example of a processing system according to the invention is illustrated. The system comprises:

[0050] - first and second enclosures 1, 1',

[0051] - a generator 2,

[0052] - first and second mixing units 3, 3' contained respectively in the first and second enclosures 1, 1', and

[0053] - a switching unit 4 for connecting the first and second speakers 1, 1' to the generator 2.

[0054] As will become apparent in the remainder of the description, the presence of a switching unit 4 makes it possible to sequentially supply two separate enclosures 1, 1' with electromagnetic waves from a single generator 2. This makes it possible to limit the production costs associated with the treatment of a biomass / solvent mixture:

[0055] - on the one hand by reducing the number of generators required to supply electromagnetic waves to the treatment system, and

[0056] - on the other hand by allowing an operator to carry out, on an enclosure 1, operations linked to production (cleaning, loading the enclosure with biomass / solvent mixture to be treated, etc.) or maintenance) while a biomass / solvent mixture is treated in the other enclosure 1'.

[0057] This switching unit was also designed to limit the risks of arcing and electromagnetic wave leakage to the outside of the treatment system.

[0058] 2.1 Speakers

[0059] Enclosure 1 makes it possible to define an enclosed space in which it is possible to generate a depression (or an overpressure), that is to say a space in which it is possible to reduce (or increase) the pressure to a value lower (or higher) than atmospheric pressure, in particular to a pressure between 50 and 950 mbar.

[0060] Each enclosure 1, 1' is configured to withstand pressures greater than or less than atmospheric pressure. Furthermore, each enclosure 1, 1' is configured to resist corrosion. Finally, each enclosure 1, 1' is configured to withstand temperatures greater than or equal to 200°C.

[0061] Such enclosures 1, 1' may have different shapes and be made from different conductive materials to perform this function. In the embodiment illustrated in Figure 2, each enclosure 1, 1' has a cylindrical shape, and is essentially made of stainless steel plates.

[0062] Each sealed enclosure 1, 1' comprises: a lower partition 11, 11' forming a bottom of the enclosure 1, 1', a curved upper partition 12, 12' forming a ceiling of the enclosure 1, 1', and one (or more) vertical lateral partition(s) 13, 13' extending between the upper and lower partitions 11, 11' and 12, 12'.

[0063] The enclosure can have a volume between 0.1 m 3 and 10 m 3 The power of the electromagnetic waves generated by the treatment device advantageously allows extraction to be carried out in such enclosure volumes.

[0064] The lower partition 11, 11' may be flat or concave towards the inside of the enclosure 1, 1'. It comprises an orifice 111, 111' to allow an operator to access the inside of the enclosure 1, 1'. In operation, this orifice 111, 111' is closed by a hatch (or door) 112, 112' normally locked in a sealed manner by any technique known to those skilled in the art, for example by bolting the hatch 112, 112' to the lower partition 11, 11', a sealing gasket (for example made of rubber) being mounted between the orifice 111, 111' and the facing hatch 112, 112' (i.e. between the edges of the orifice and the edges of the hatch facing each other). Of course, the lower partition 11, 11' may comprise more than one orifice 111, 111' which can be closed by a hatch 112, 112'.Furthermore, the reader will appreciate that this (or these) orifice(s) 111, 111' which can be closed by one or more hatches 112, 112' can be arranged in a partition 12, 12' and 13, 13' other than the lower partition 11, 11'.

[0065] The upper partition 12, 12' comprises a through inlet 121, 121' at which the switching unit can be connected. Thus, the incident waves (electromagnetic waves produced by the generator 2) circulating in the switching unit 4 emerge in the enclosure 1, 1' through the inlet 121, 121'. Of course, this inlet 121, 121' may be provided in the side partition 13, 13' rather than the upper partition 12, 12'. The upper partition 12, 12' may comprise one (or more) other inlet(s), for example for the passage of a shaft of the mixing unit 3, 3'.

[0066] Each enclosure 1, 1' may comprise a hole to which a pump (not shown) is connected for generating a vacuum in the enclosure 1, 1'.

[0067] Such an enclosure 1, 1' being known to those skilled in the art, it will not be described in more detail below.

[0068] 2.2 Generator

[0069] The generator 2 is configured for the emission of electromagnetic waves of frequency between 10 MHz and 100 GHz, preferably between 433 MHz and 30 GHz, and even more preferably between 915 MHz and 28 GHz, corresponding to waves in the microwave domain.

[0070] The person skilled in the art will be able to choose the frequency most suited to the implementation of the process, in particular depending on the biomass, to optimize the extraction process. Advantageously, the frequency of the electromagnetic waves ranges from 915 MHz to 2.45 GHz. Advantageously, the frequency of the electromagnetic waves will be chosen according to known industrial devices for generating electromagnetic waves on an industrial scale, in particular electromagnetic wave generators with frequencies below 1500 MHz, more advantageously around 915 MHz.

[0071] The skilled person will also know how to choose the power of the electromagnetic waves best suited to the biomass and the extracts obtained. The power of the electromagnetic waves advantageously ranges from 300 W to 10 MW, more advantageously from 500 W to 100 kW, even more advantageously from 1 kW to 75 kW. This power will be chosen in particular according to the volume to be treated and the time that will be necessary for the extraction. For example, the power of the electromagnetic waves can be chosen according to the following ratio: for 1 kg of material to be extracted the power of the electromagnetic waves is from 1 to 10 kW, ideally 2 to 6 kW.

[0072] Conventionally, the generator 2 comprises one (or more) source(s) of electromagnetic waves (not shown) of solid state or transistor type housed in a protective casing 21, and an output opening 22 - formed in an upper plate of the protective casing 21 - for the emission of electromagnetic waves towards the outside of the generator 2.

[0073] 2.3 Brewing unit

[0074] Each mixing unit 3, 3' allows the biomass / solvent mixture to be mixed to be treated in order to homogenize the treatment of this mixture. As indicated previously, each mixing unit 3, 3' is associated with a respective enclosure 1, 1'.

[0075] Each stirring unit 3, 3' may comprise a propeller including a shaft and two (or four) blades at one end of the shaft, the other end of the shaft being connected to a motor to induce rotation of the shaft and the blades of the propeller.

[0076] Alternatively, each mixing unit 3, 3' may comprise ejection nozzles mounted in the lower partition 11, 11', these nozzles allowing the injection of a gas — inert such as air — into the mixture to induce its mixing. Of course, those skilled in the art will be able to envisage other types of mixing unit 3, 3' for the biomass / solvent mixture to be treated.

[0077] Preferably, mixing is carried out by rotating the blades at a rotation speed ranging from 3 to 20 revolutions per minute.

[0078] 2.4 Switching Unit

[0079] The switching unit 4 makes it possible to sequentially connect the first and second enclosures 1, 1' to the generator 2. More precisely, the switching unit 4 is configured to be moved between: a first extreme position in which the generator 2 is connected to the first enclosure 1 via the switching unit 4, as illustrated in Figure 3a, and a second extreme position in which the generator 2 is connected to the second enclosure 1' via the switching unit 4, as illustrated in Figure 3b.

[0080] The movement of the switching unit 4 between the first and second extreme positions may be ensured by one (or more) motor(s), by one (or more) jack(s) or by any other means known to those skilled in the art. Advantageously, the switching unit 4 may comprise one (or more) sensor(s) for detecting whether the switching unit 4 is in the first extreme position or in the second extreme position, the generator being able to be activated for the production of electromagnetic waves only if the sensor(s) has (have) detected that the switching unit 4 is in the first extreme position or the second extreme position.

[0081] When the switching unit 4 is in the first extreme position, the first enclosure 1 is coupled to the generator 2 via the switching unit 4, while the second enclosure 1' is decoupled from the generator 2. Thus, the electromagnetic waves produced by the generator 2 circulate to the first enclosure 1 through the switching unit 4, the second enclosure 1' receiving no electromagnetic waves. It is thus possible for an operator to carry out loading or maintenance operations on the second enclosure 1' without risk of electromagnetic wave radiation. When the switching unit 4 is in the second extreme position, the second enclosure 1' is coupled to the generator 2 via the switching unit 4, while the first enclosure 1 is decoupled from the generator 2.Thus, the electromagnetic waves produced by the generator 2 circulate to the second enclosure 1' through the switching unit 4, the first enclosure 1 not receiving any electromagnetic waves. It is thus possible for an operator to carry out loading or maintenance operations on the first enclosure 1 without risk of electromagnetic wave radiation.

[0082] This maximizes the uptime of Generator 2 for batch production of polyphenol-rich extract, and therefore the productivity of the processing system.

[0083] The switching unit 4 comprises: a tubular waveguide 41, and first and second connection cells 42, 43 arranged at a respective end of the waveguide 4L

[0084] The waveguide 41 allows the circulation of the electromagnetic waves produced by the generator 2 towards one or other of the first and second enclosures 1, 1'. It may consist of a parallelepiped tube of rectangular cross-section (waveguide standardized to the frequency used), for example U-shaped as illustrated in Figure 2. Such a waveguide 41 is made of a material impervious to electromagnetic waves, for example of an electrically conductive and non-magnetic material (metal) of the stainless steel or aluminum type.

[0085] The first and second connection cells 42, 43 are configured to be connected with the outlet opening 22 on the one hand, and with the through inlet openings 121, 121' on the other hand.

[0086] Each connection cell 42, 43 is configured to trap electromagnetic waves likely to escape to the outside of the treatment system at the interface between the generator 2 and the switching unit 4 on the one hand, and at the interface between the first and second enclosures 1, 1' and the switching unit 4 on the other hand. This makes it possible to envisage moving the switching unit 4 while avoiding screw fixing, and therefore to limit the operating time.

[0087] Thus, the first and second connection cells 42, 43 make it possible to limit the risks of leakage of high-power electromagnetic waves to the outside of the treatment system. Furthermore, the first and second connection cells 42, 43 make it possible to reduce the risks of electric arc formation (in the event of false contact between two metal parts) in the first enclosure 1 and the second enclosure 1'.

[0088] Each connection cell 42, 43 has the shape of a metal frame intended to be positioned around the outlet opening 22 or the inlet mouth 121, 121' with which said connection cell 42, 43 is associated. This curved metal frame in a loop of rectangular section comprises an entry / exit slot 425 for the electromagnetic waves. The dimensions of the frame are determined so that the electromagnetic waves entering the metal frame at the entry / exit slot 425, exit said metal frame in phase opposition and cancel each other out. This principle makes it possible to produce a virtual metal / metal contact but equivalent to a “real” metal / metal contact.

[0089] These connection cells 42, 43 make it possible to capture the reflected waves coming from: the first enclosure 1 at the level of the inlet opening 121, the second enclosure 1' at the level of the inlet opening 121', and the generator 2 at the level of the outlet opening 22.

[0090] With reference to Figure 4, an example of a connection cell 42 in the first extreme position is shown in cross section (connection cell 42 positioned on the through-mouth 121 of the first enclosure 1).

[0091] The connection cell 42 comprises: a central channel 426 whose dimensions are identical to the dimensions of the inlet openings 121, 121' and the outlet opening 22 of the generator 2, and an interior chamber C, the central channel 426 and the chamber C being delimited by a plate curved in a loop, here of rectangular shape, with a free face 421 configured to extend opposite the partition 12 in which the through opening 121 is formed.

[0092] More specifically, the connection cell 42 comprises: an external vertical panel 422 extending perpendicular to the partition 12, the external vertical panel 422 having a lower edge 422a in contact with the partition 12, and an upper edge 422b opposite the lower edge 422a, an upper panel 423 extending parallel to the partition 12, the upper panel 423 having an external lateral edge 423a connected to the upper edge 422b of the external vertical panel 422, and an internal lateral edge 423b extending in line with the inlet mouth 121, an internal vertical panel 424 extending parallel to the external vertical panel 422, the internal vertical panel 424 having an upper edge 424a connected to the internal lateral edge 423b of the upper panel 423, and a lower edge 424b opposite the lower edge 424 b being closer to the inlet mouth 121 than the upper edge 424a, the free side 421 extending parallel to the partition 12,the free panel 421 having a connecting edge 421a connected to the lower edge 424b of the internal vertical panel 424, and an opposite free edge 421b, the free edge being closer to the external vertical panel 422 than the connecting edge 421a.,

[0093] The free panel 421 extends opposite the partition 12, at a non-zero distance d from it so that the free panel 421 is not in physical contact with the partition 12. Thus, the free panel 421 defines with the partition 12 a passage forming the entry / exit slot 425 of the wave trap constituted by the connection cell 42.

[0094] Advantageously, the dimensions of the different sections 421-424 (and in particular the widths L1, L2, L3 and L4 of the different sections) are determined (experimentally or by modeling) to be equal to a multiple of the wavelength of the reflected waves plus a quarter of the latter so that the reflected waves leaving the connection cell 42 (hereinafter referred to as “outgoing reflected waves”) are out of phase by half a wavelength with the reflected waves entering the connection cell 42 (hereinafter referred to as “incoming reflected waves”). The incoming and outgoing reflected waves are thus in phase opposition and cancel each other out.

[0095] Indeed, the operating principle of the connection cell 42 (forming a wave trap) is based on the combination of two waves (incoming wave and outgoing wave) which cross in phase opposition at the level of the input / output slot 425.

[0096] In the case of the system according to the invention, the waves reflected by the enclosure 1 propagate to the mouth 121 and penetrate into the connection cell 42 at the level of the entry / exit slot 425. These reflected waves propagate in the connection cell 42 following the different sections 421-424 constituting it, to exit the connection cell 42 via the entry / exit slot 425. The waves exiting the connection cell 42 interfere with the waves entering the connection cell 42.

[0097] The phase of the outgoing waves depends on the distance traveled (D p ) in the connection cell 42, and in particular the widths of the different sections 421-424 constituting the connection cell 42 (D p =L2 + L3 + L4 + 2xLi).

[0098] Under phase opposition conditions, these incoming and outgoing waves OE, OS cancel each other out.

[0099] The determination of the dimensions of the connection cell 42 forming a wave trap can be carried out experimentally, or be carried out on the basis of modeling results.

[0100] Such connection cells 42, 43 make it possible to limit the risks of leakage of reflected waves to the outside as well as the risks of generation of electric arcs at the level of the inlet vents 121, 121'.

[0101] 2.5 Metal plate To facilitate the connection of the switching unit 4 to the inlet openings 121, 121' of the first and second enclosures 1, 1', and to the outlet opening 22 of the generator 2, the system may comprise a metal plate to which the first and second enclosures 1, 1' and the generator 2 are connected.

[0102] This substantially planar metal plate comprises first, second and third aligned through-lights of identical dimensions.

[0103] The first light is connected to the inlet mouth 121 of the first enclosure 1, the second light is connected to the outlet opening 22 of the generator 2 (the second light being positioned between the first and third lights), and the third light is connected to the inlet mouth 121' of the second enclosure 1'.

[0104] The dimensions of the first, second and third lumens are identical to the dimensions of the central channels 426 of the first and second connection cells 42, 43. The distance separating the centers of the first lumen and the second lumen is further equal to the distance separating the centers of the second lumen and the third lumen. This distance is further equal to the center distance E (see FIG. 5) between the first and second connection cells 42, 43.

[0105] Thus, when the switching unit 4 is: in the first extreme position (figure 3a), the central channel of the first connection cell 42 is aligned with the first light, while the central channel of the second connection cell 43 is aligned with the second light, in the second extreme position (figure 3b), the central channel of the first connection cell 42 is aligned with the second light, while the central channel of the second connection cell 43 is aligned with the third light.

[0106] 3. Operating principle

[0107] In conventional treatment devices of the prior art, the activation time of the generator 4 for the production of electromagnetic waves is very limited. Indeed, a large part of the treatment time is occupied by the loading, unloading and cleaning times to which must be added the time linked to the reaction kinetics (depression, heating, cooling of the enclosure).

[0108] Given the high cost of generator 2, it is preferable to maximize its activation time, in order to reduce the costs associated with processing the mixture. However, it is not possible to imagine a manual switching operation by disassembling and reassembling the various components (waveguide 3, impedance matching unit 5, wave trapping unit 6, coupling unit 8) of the device positioned between the generator and enclosure 1.

[0109] As indicated previously, the switching unit 4 of the system according to the invention makes it possible to alternately connect the first and second enclosures 1, 1' to the generator 2 according to the following operating principle.

[0110] In a first step, the first and second reaction chambers 1, 1' are loaded with the product to be treated.

[0111] The switching unit 4 is then moved by suitable moving means (motor(s), jack(s), etc.) into the first extreme position: the first connection cell 42 is connected to the inlet mouth 121 of the first enclosure 1, and the second connection cell 43 is connected to the outlet opening 22 of the generator 2.

[0112] Advantageously, the switching unit 4 may comprise safety contactors for detecting whether the first and second connection cells 42, 43 are correctly connected to the inlet mouth 121 and to the outlet opening 22, activation of the generator 2 being authorized only when a correct connection is detected. When the switching unit 4 is in the first extreme position, the generator 2 is activated to produce electromagnetic waves. These electromagnetic waves propagate towards the output of the generator 2 at the outlet opening 22, enter the second connection cell 43, pass through the waveguide 41, enter the first connection cell 42, and emerge in the first reaction chamber 1 at the inlet mouth 121. The first stirring unit 3 mixes the product during the application of the electromagnetic waves for the treatment of said product.

[0113] When the product has been processed, generator 2 is deactivated.

[0114] The switching unit 4 is then moved from the first extreme position to the second extreme position. In particular, the switching unit 4 is moved in translation in a direction parallel to a longitudinal axis A-A' (and in a direction opposite to the first enclosure 1) to dissociate: the first connection cell 42 from the upper partition 12 of the first enclosure 1, and the second connection cell 43 from the upper plate of the protective casing 21.

[0115] Once the first and second connection cells 42, 43 are separated from the first enclosure 1 and the generator 2, the switching unit 4 is moved in translation in a direction perpendicular to the longitudinal axis A-A' so that: the first connection cell 42 comes in line with the outlet opening 22 of the generator 2, and the second connection cell 43 comes in line with the inlet mouth 121' of the second enclosure 1'.

[0116] When the first and second cells are correctly positioned above the outlet opening 22 and the inlet mouth 121' respectively, the displacement means induce the translational displacement in a direction parallel to the longitudinal axis A-A' (towards the second enclosure 1') so that: the first connection cell 42 is connected to the outlet opening 22 of the generator 2, and the second connection cell 43 is connected to the inlet mouth 121' of the second enclosure 1'.

[0117] When the switching unit 4 is in the second extreme position, the generator 2 is activated to produce electromagnetic waves. These electromagnetic waves propagate towards the output of the generator 2 at the outlet opening 22, enter the first connection cell 42, pass through the waveguide 41, enter the second connection cell 43, and open into the second reaction chamber 1 'at the inlet mouth 121'. The second stirring unit 3' mixes the product when applying the electromagnetic waves for the treatment of said product.

[0118] During the application of electromagnetic waves to the product contained in the second enclosure 1', an operator can carry out maintenance operations in the first enclosure 1 (extraction of the treated product, cleaning of the first enclosure 1, reloading of the first enclosure 1 with a new product to be treated, etc.) without risk of being irradiated by the electromagnetic waves generated by the generator 2.

[0119] Once the product contained in the second enclosure 1' has been processed, the generator 2 is deactivated, the switching unit 4 is moved to the first extreme position, and the generator 2 is reactivated to process the product contained in the first enclosure 1. The operator can then carry out the necessary maintenance operations in the second enclosure 1' without risk to his safety.

[0120] These different operations can be repeated to allow batch processing of a product in the first and second enclosures 1, 14 from a single generator 2.

[0121] The reader will understand that many modifications may be made to the invention described above without materially departing from the new teachings and advantages presented herein. For example, the treatment system described above may comprise more than two enclosures. BRIEF DESCRIPTION OF THE DRAWINGS

[0122] Other advantages and characteristics of the invention will emerge more clearly from the following description of several variant embodiments, given as non-limiting examples, from the appended drawings in which:

[0123] - Figure 1 is a general schematic representation of a device for treating a product using electromagnetic waves,

[0124] - Figure 2 is a schematic representation of a treatment system according to the invention for the preparation of a dry plant biomass extract, - Figure 3a is a schematic representation of a switching unit of the treatment system illustrated in Figure 2, said switching unit being in a first extreme position,

[0125] - Figure 3b is a schematic representation of the switching unit in a second extreme position, - Figure 4 is a schematic representation of a connection cell of the switching unit illustrated in Figures 3a and 3b,

[0126] - Figure 5 is a schematic perspective representation of the switching unit illustrated in Figures 3a and 3b.

Claims

CLAIMS 1. A system for treating plant biomass, the treatment system comprising: first and second enclosures (1, 1') intended to contain the plant biomass to be treated, each of the first and second enclosures (1, 1') comprising a lower partition (11, 11'), an upper partition (12, 12') and at least one lateral partition (13, 13') extending between the upper and lower partitions (11, 12; 11', 12'), the upper partition (12, 12') including a through inlet (121, 121'), a generator (2) for producing electromagnetic waves, the generator (2) comprising a protective casing (21), at least one source of electromagnetic waves housed in the protective casing (21), and an outlet opening (22) provided in an upper plate of the protective casing (21), first and second stirring units (3, 3') contained respectively in the first and second enclosures (1, 1'),characterized in that the processing system further comprises a switching unit (4) including: a tubular waveguide (41) for the circulation of electromagnetic waves between the generator (2) and the first and second enclosures (1, 1'), and first and second connection cells (42, 43) arranged at a respective end of the waveguide (41), said switching unit (4) being movable between: a first extreme position in which the first connection cell (42) is connected to the inlet mouth (121) of the first enclosure (1) and the second connection cell (43) is connected to the outlet opening (22) of the generator (2) so that the electromagnetic waves produced by the generator (2) are transmitted to the first enclosure (1) via the switching unit (4),and a second extreme position in which the first cell (42) is connected to the outlet opening (22) of the generator (2) and the second connection cell (43) is connected to the inlet mouth (121') of the second enclosure (1') so that the electromagnetic waves produced by the generator (2) are transmitted to the second enclosure (1') via the switching unit (4)., 2. Treatment system according to claim 1, which further comprises a metal plate including first, second and third aligned through-lights of identical dimensions, the distance between the centers of the first and second through-lights being equal to the distance between the centers of the second and third through-lights: the first light being connected to the inlet mouth (121) of the first enclosure (1), the second light being connected to the outlet opening (22) of the generator (2), and the third light being connected to the inlet mouth (121') of the second enclosure (1'), the switching unit (4) being in contact with the metal plate in the first and second extreme positions.

3. A processing system according to any one of claims 1 or 2, wherein each of the first and second connection cells (42, 43) comprises a metal frame curved into a rectangular loop, said frame including an electromagnetic wave entry / exit slot, the dimensions of said frame being determined so that electromagnetic waves entering the metal frame at the entry / exit slot, exit said metal frame in phase opposition at the entry / exit slot.

4. Processing system according to claims 2 and 3 taken in combination, in which the frame comprises: an outer panel (422) extending perpendicular to the metal plate, an inner panel (424) parallel to the outer panel (422), the distance between the metal plate and the edge (424b) of the inner panel (424) closest to the metal plate being non-zero when the switching unit (4) is in the first or second extreme position, an upper panel (423) between the outer and inner panels (422, 424), the edges (423a, 423b) of the upper panel (423) being connected to the edges (422b, 424a) of the outer and inner panels (422, 424) furthest from the metal plate, and a lower panel (421) parallel to the upper panel (423), the lower panel extending between the outer and inner panels (422, 424) and including: o a connecting edge connected to the edge (424 b) of the inner panel (424) closest to the metal plate, o a free edge opposite the connecting edge, so that the lower panel (421) extends opposite the metal plate, at a non-zero distance from said metal plate when the switching unit (4) is in the first or second extreme position, said lower panel (421) not being in contact with either the metal plate or the outer panel (422).

5. Treatment system according to claim 4, in which each panel is of overall rectangular shape, the sum of the widths: of the external panel, of the upper panel, of the internal panel, and of the lower panel being equal to a multiple of the wavelength of the electromagnetic waves added to a quarter of the wavelength of said electromagnetic waves.

6. Processing system according to any one of claims 4 or 5, in which the thickness of the panels is substantially equal to the thickness of the walls of the waveguide (41).

7. A processing system according to any one of claims 3 to 6, wherein each of the first and second connection cells (42, 43) comprises a central channel whose dimensions are identical to the dimensions of the first, second and third through-lights, the center distance between the first and second connection cells (42, 43) being equal to the distance separating the centers of the first and second through-lights.

8. Processing system according to any one of claims 1 to 7, which further comprises means for moving the switching unit (4) between the first and second extreme positions, said moving means being configured to implement the following operations successively, when the switching unit (4) is in the first extreme position: moving the switching unit (4) in vertical translation so as to: o dissociate the first connection cell (42) from the inlet opening (121) of the first enclosure (1), and o dissociate the second connection cell (43) from the outlet opening (22) of the generator (2), moving the switching unit (4) in horizontal translation so as to: o position the first connection cell (42) in line with the outlet opening (22) of the generator (2), and o position the second connection cell (43) in line with the inlet opening (121') of the second enclosure (1'), moving the switching unit (4) in vertical translation so as to: o connect the first connection cell (42) to the outlet opening (22) of the generator (2), and o connect the second connection cell (43) to the inlet opening (121') of the first enclosure (1').

9. A treatment system according to claim 8, wherein the switching unit further comprises at least one sensor for detecting whether the switching unit (4) is in the first extreme position or the second extreme position, the generator being able to be activated for the production of electromagnetic waves only if said and at least one sensor has detected that the switching unit (4) is in the first extreme position or the second extreme position.

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