Continuous microwave extraction device with conveyor belt

Abstract

The invention relates to a microwave device for extracting volatile substances or liquids from organic material by gravimetric analysis, comprising (a) a microwave unit having an inlet and an outlet for the organic material, (b) at least one conveyor belt (1) for transporting the organic material from a loading zone through the microwave unit to an unloading zone, the invention relates to an extraction device (1) for extracting water from a container (2), the upper surface of which has a plurality of transverse partitions (4) defining therebetween a plurality of extraction zones (3) having a substantially flat surface and comprising drainage holes (5), where each transverse partition (4) has a transverse chamber (6) therethrough, within which a rod (7) is housed, the rod (7) extends beyond half the length of the transverse bulkhead and beyond half the height of the transverse bulkhead, where the rod (7) comprises a rigid central core (7a) comprising a rigid electrically conductive material.

Description

Technical Field

[0001] The present invention relates to the field of extracting natural organic compounds from biomass by dielectric heating. More specifically, the present invention relates to a microwave extraction process using a conveyor belt. Background Art

[0002] The extraction of valuable compounds in liquid or vapor form can be carried out by various extraction modes. Solvent-free continuous microwave-assisted extraction has proven to have particular advantages due to the absence of solvent use and the high quality of the obtained extracts.

[0003] To achieve continuous processing of raw materials, microwave equipment typically adopts an open design on the inlet side and the outlet side. Commonly used strategies for reducing microwave leakage are using microwave reflectors, mesh baffles, or water jackets. Another drawback of open microwaves is the leakage of volatile substances, which may affect the extraction yield and the working quality of operators.

[0004] Existing conveyor belts do not participate in reducing the leakage of volatile substances or microwaves, and thus do not improve the extraction yield, safety, and the working conditions of operators in this way.

[0005] The conveyor belt is crucial for continuous microwave extraction because the conveyor belt not only transports raw materials but also serves as the processing site for raw materials. Therefore, the conveyor belt should retain the raw materials and allow the released extracted liquid. Existing conveyor belts are defective in extracting liquids and / or vapors into different biomasses to obtain food-grade extracts. In fact, existing conveyor belts lack a suitable structure to collect liquids and retain biomasses.

[0006] In addition, the cleaning of traditional conveyor belts and cross-contamination between batches may also be a problem because the materials used may be permeable or absorb liquids, volatile substances (such as cement and graphite powder), or may be complex to clean due to their structure itself. Any of these reasons may cause microbial risks or cross-contamination between batches.

[0007] The stability of materials under extreme conditions, usually repeated exposure to acidic or alkaline environments at high temperatures, will significantly shorten the service life of existing conveyor belts.

[0008] Existing conveyor belts are not suitable for continuous microwave extraction. In fact, some problems cannot be observed in batch (intermittent) processing because the processing time cannot last, for example, continuously for 7 hours. Usually, some conveyor belts recommended for microwave extraction will generate arcs or hot spots at extremely high temperatures due to the materials used. Arcs are considered very dangerous in industrial facilities due to the explosion risk, and the hot spots generated inside the processed biomass will significantly reduce the microwave extraction rate and especially generate a burnt smell in the extracts.

[0009] The object of the present invention is to provide an improved conveyor belt device for the microwave extraction of organic materials.

[0010] This object is achieved by the features of the independent claims. The dependent claims further elaborate on the central idea of the invention. Summary of the Invention

[0011] One aspect relates to a microwave device for extracting volatile substances or liquids from organic materials by gravimetry, comprising:

[0012] (a) A microwave unit having an inlet and an outlet for the organic material,

[0013] (b) At least one conveyor belt for transporting the organic material from a loading area through the microwave unit to an unloading area,

[0014] wherein the conveyor belt comprises a belt having a plurality of transverse partitions on its upper side, and a plurality of extraction zones are defined between these transverse partitions, the extraction zones having a substantially flat surface and including drainage holes,

[0015] wherein each transverse partition has a transverse chamber passing through it, and a rod is accommodated in the transverse chamber, the rod extending more than half of the length of the transverse partition and more than half of the height of the transverse partition,

[0016] wherein the rod comprises a rigid central core which can be embedded in a preferably elastic outer layer made of a microwave-transparent material, and the rigid central core comprises a rigid electrical conductor material.

[0017] The outer layer of the conveyor belt and / or at least the extraction zones may comprise a material having one, more or all of the following properties:

[0018] - A dielectric loss tangent of less than 0.01,

[0019] - A dielectric constant of less than 4, and

[0020] - A heat resistance up to 300 °C.

[0021] The drainage holes may be holes having an average diameter (d) of 0.001 to 30 mm, preferably 0.01 to 20 mm.

[0022] The ratio of the distance (dp) between two transverse partitions to the length (D) between the inlet and the outlet of the microwave unit is from 1 to 0.003.

[0023] The ratio h / H of the height (h) of the transverse partition to the height (H) of the distance between the upper surface of the extraction zone and the upper boundary of the inlet and / or the outlet is from 0.99 to 0.2.

[0024] The longitudinal edge (L) includes semi-rigid or rigid slats disposed between the partitions.

[0025] The semi-rigid or rigid slats can be formed of a material having a dielectric loss tangent of less than 0.01, a dielectric constant of less than 4, and heat resistant up to 300 °C.

[0026] The outer layer can include a material having one, more, or all of the following properties:

[0027] - A maximum continuous operating temperature (measured according to ISO 2578 test method with a service temperature starting from 20,000 hours) up to 155 °C, preferably up to 260 °C, and / or

[0028] - A thermal conductivity of less than 1 W / mK, preferably less than about 0.50 W / mK, and / or

[0029] - Very good solvent resistance (ASTM D543), preferably equal to excellent, and / or

[0030] - A water absorption rate of less than 0.03% (ASTM D570), preferably equal to 0.0001%, and / or

[0031] - A coefficient of friction (ASTM D3702) of less than 0.4, preferably equal to or less than 0.1.

[0032] The rigid central core can be made of a conductive material such as copper, steel, aluminum, lead, tin, zinc, brass, gold, or silver.

[0033] Another aspect relates to a method for extracting a liquid composition and / or volatile substances from an organic material, including the step of using the device as defined above.

[0034] The method can include the steps of: conveying the organic material from a loading area outside the microwave unit to an inlet through at least one conveyor belt, then through the microwave unit to an outlet, and then to an unloading area outside the microwave unit.

[0035] The method can include the step of discharging the extracted liquid composition and / or volatile substances through one or preferably more discharge holes.

[0036] [[ID=3,6]]The method can include the step of heating the organic material, such as by dielectric heating. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The further advantages, objects, and features of the present invention will now be explained with reference to the drawings.

[0038] Figure 1 A sectional side view of a microwave extraction device with a conveyor belt according to the present invention is shown,

[0039] Figure 2 A top view of a conveyor belt according to the present invention is shown.

[0040] Figure 3 A sectional side view of different partitions of a conveyor belt according to the present invention is shown,

[0041] Figure 4 A perspective view of a conveyor belt with partitions according to the present invention is shown,

[0042] Figure 5 An embodiment is shown in which the slats are arranged parallel to the edge of the conveyor belt, and

[0043] Figure 6 is Figure 5 a perspective view of the embodiment. Detailed Description

[0044] Figure 1 A microwave extraction device for extracting organic materials entering and leaving a microwave cavity 2 is shown. The organic materials are conveyed by a conveyor belt 1, enter the microwave cavity 2 from an inlet 2a, and leave the microwave cavity from an outlet 2b.

[0045] The organic materials can be loaded onto the upper side of the conveyor belt 2 at a loading area LA in front of the inlet 2a, and can be discharged from the upper side of the belt at an unloading area UA downstream of the outlet 2b.

[0046] On the upper part (outer side) of the conveyor belt, a plurality of preferably equally spaced partitions 4 are arranged parallel and at right angles to the side edge L of the conveyor belt, thereby defining an extraction area 3 for the organic materials between them.

[0047] As described below, the partitions 4 are arranged (mechanically) to define a space for accommodating and separating the organic materials. They are also arranged by including a conductive material so as to cooperate with the inlet and outlet of the microwave cavity (by closing them when passing through, thereby reducing microwave leakage). In addition, their material design is also selected to actively promote the microwave distribution in the microwave cavity and the heating of the organic materials, thereby promoting their extraction.

[0048] The microwave cavity 2 is provided with one or more microwave generators, preferably arranged above the conveyor belt 2 inside the microwave cavity 2.

[0049] The length of the microwave cavity is D.

[0050] The gap between the upper side of the belt (outer side of the partition 4) and the upper edge of the generally rectangular inlet 2a is denoted by H.

[0051] The height of the partition (measured from the upper side of the belt) is denoted by h.

[0052] The length of the extraction area measured between the opposite sides of the partition 4 is denoted by dp.

[0053] Thus, a microwave device for extracting volatile substances or liquids from organic materials may include:

[0054] (a) A microwave unit (cavity) 2 having an inlet 2a and an outlet 2b for the organic material,

[0055] (b) A mechanism for introducing the organic material into the device at a loading zone LA;

[0056] (c) A mechanism for removing the organic material from an unloading zone UA;

[0057] (d) At least one conveyor belt 1 for transporting the organic material from the loading zone LA through the microwave unit to the unloading zone UA.

[0058] The conveyor belt 1 has a conveyor belt that includes two parallel longitudinal edges L and a central region C on the lower surface of the conveyor belt, which has a substantially flat surface. On the upper surface, transverse partitions 4 extend from one longitudinal edge L to the other longitudinal edge L. Thus, the upper surface of the conveyor belt is divided into a plurality of extraction zones 3 for receiving the organic material to be extracted. The extraction zones 3 have a substantially flat surface. To discharge the (extracted) liquid composition, the extraction zones 3 have one or preferably a plurality of discharge openings. These discharge openings can be, for example, holes 5. The holes 5 can be circular or rectangular (thus the extraction zones have a grid structure). Their average diameter (d) can be from 0.001 to 30 mm, preferably from 0.01 to 20 mm.

[0059] As Figure 3 and Figure 4 shown, the partition 4 can form a double-layer sleeve, where the side walls of the sleeve are not connected, thus forming a tubular chamber (channel) 6. The sleeve of the partition 4 can be made of the same material as the belt. This material is preferably microwave-transparent. The sleeve can be continuously formed with the belt material or can be a separate element that is connected to the flat belt material at the bottom of the sleeve.

[0060] At the bottom of the partition 4, the side walls of the sleeve are typically spaced apart. Typically, the sleeve side walls are made of a continuous material. Thus, the cross-section of each partition can taper towards the top of the partition 4. The sleeve material is typically a flexible or soft material or a rigid material. It has no openings or pores. It can be a single-layer or multi-layer material.

[0061] The transverse channel defined by the sleeve of the partition 4 houses a preferably rigid insert, which can be a rigid rod 7. The rod 7 can extend more than half the length of the transverse partition and more than half the height of the transverse partition.

[0062] The rod 7 can be made of a single material, preferably a rigid material, or it can also be a composite rod 7 composed of at least two different and independently arranged materials. If it is a composite rod, at least one of the materials is rigid.

[0063] In a preferred embodiment, the rod 7 includes a rigid central core 7a, which can be embedded in a preferably elastic outer layer 7b. Preferably, the rigid central core 7 is made of a rigid electrical conductor material. Preferably, the outer layer 7b completely covers the core 7a except for the core base.

[0064] The sleeve is also preferably closed at its bottom to be loosely inserted into the rod. The side wall of the sleeve is preferably not connected to the rod. Alternatively, the rod can be connected to the sleeve of the partition (fixed in place relative to the sleeve).

[0065] The elastic outer layer 7b of the conveyor belt and / or the extraction zone 3 can be made of a material having one or more of the following characteristics (preferably all characteristics):

[0066] - The dielectric loss tangent is less than 0.01, preferably less than 0.005, and preferably less than 0.001.

[0067] - The dielectric constant is less than 4, preferably less than 3.3, and preferably less than about 2.1, and

[0068] - The heat resistance can reach 300 °C, preferably 200 °C, and typically 150 °C.

[0069] The size of the conveyor belt is adapted to the microwave oven so that the conveyor belt can at least transfer the raw material from the loading area through the microwave device to the unloading area.

[0070] Typically, the width of the conveyor belt is 8 cm to 1.5 m, preferably 10 cm to 1 m, and more preferably 15 cm to 0.8 m.

[0071] The height h of the transverse partition 4 is adapted to the microwave unit. Typically, relatively speaking, the height h of the transverse partition 4 is slightly lower than the height H of the distance between the upper surface of the extraction zone 3 and the upper edges of the inlet 2a and / or the outlet 2b. The h / H ratio is 0.99 to 0.2, preferably 0.8 to 0.5.

[0072] In absolute terms, the difference between the height h of the transverse partition 4 and the height H of the distance between the upper surface of the extraction zone 3 and the upper edges of the inlet 2a and / or the outlet 2b (usually horizontal edges) is preferably 2 cm to 0.2 cm, more preferably 1 cm to 0.3 cm, 1 mm to 5 mm; or 1.5 mm to 2 mm.

[0073] Advantageously, the height h of the transverse partition 4 is 1 cm to 20 cm, preferably 2 to 15 cm, more preferably 3 to 10 cm or 4 to 9 cm or 5 to 7 cm.

[0074] In one embodiment, each partition is provided with a rod having a rigid core 7a. In other embodiments, only every nth partition (e.g., every other partition) is provided with such a rod. The thickness of the rigid central core 7a of the transverse partition 4 can be 0.5 to 15 mm, preferably 1 to 5 mm, typically 2 mm.

[0075] The thickness of the elastic outer layer of the transverse partition 4 can be 0.01 to 2 cm, preferably 0.1 to 1 cm, more preferably 0.2 to 0.9 cm.

[0076] The outer layer 7b can be coated onto the rigid core 7a.

[0077] Advantageously, the spacing of the transverse partitions 4 should be adapted to the size (length) of the microwave unit. Typically, in order to significantly reduce the loss of volatile substances and the leakage of microwave radiation, the ratio of the distance dp between two transverse partitions 4 to the length D between the inlet 2a and the outlet 2b should be less than or equal to 1, preferably less than or equal to 0.8, 0.7, 0.5 or 0.4.

[0078] Typically, the ratio dp / D is from 1 to 0.003, preferably from 0.8 to 0.03, more preferably from 0.6 to 0.05 or 0.5 to 0.06 or 0.5 to 0.06.

[0079] According to one embodiment, the extraction zone 3 includes holes at least in its central region, preferably all extraction zones 3 include holes.

[0080] More preferably, the extraction zone 3 is made of a woven material, or is made by 3D printing or molding. It can have a grid structure.

[0081] Advantageously, the transverse partition 4, in particular the sleeve material defining the chamber, does not include pores.

[0082] The "dielectric constant" used herein refers to the relative permittivity (ε r ) of the material. Unless otherwise specified, the term "dielectric constant" refers to the ratio of the permittivity of each material to the permittivity of vacuum. It should be understood that the relative permittivity (dimensionless) may exhibit frequency and temperature dependence. In the present invention, the "dielectric constant" refers to the value measured at 20 °C and 1,000 Hz.

[0083] The dielectric loss tangent refers to the tangent value (tan(δ)) of the dielectric loss angle (δ). Thus, the "dielectric loss angle" refers to the imaginary part (ε″) of the dielectric constant of the material and the real part (ε ′) ratio. In addition, the dielectric loss tangent is a parameter of a dielectric material that quantifies the dissipation of its inherent electromagnetic energy into heat. Here, the so-called tangent of the dielectric constant refers to the value measured at a frequency of 1 MHz and 25 °C according to the method described in ASTM D150 [2018 Edition].

[0084] Typically, the elastic outer layer 7b and at least the extraction zone 3 of the conveyor belt 1 comprise or are made of a material having a dielectric loss tangent of less than 0.01, preferably less than 0.005, and preferably less than 0.001.

[0085] Typically, the outer layer 7b and at least the extraction zone 3 of the conveyor belt 1 comprise a material having a dielectric constant of less than 4, preferably less than 3.3, and preferably less than about 2.1.

[0086] Advantageously, Teflon TM PTFE, FEP, and PFA fluoropolymers have suitable dielectric properties: a very low dielectric constant (relative permittivity) of only 2.1 over a wide frequency range from 100 Hz to 50 GHz.

[0087] Another hybrid polymer (PEEK / PTFE-5) prepared from PEEK and PTFE has a dielectric constant of 3.21 and a dielectric loss tangent of 6.00×10-3 at 10 kHz.

[0088] Other suitable materials are, for example, thermosetting materials or thermoplastic materials. Suitable materials include polymers such as 1,2-polybutadiene (PBD, 1,2-polybutadiene), polyisoprene, polybutadiene-polyisoprene copolymers, polyetherimide (PEI, polyetherimide), fluoropolymers such as polytetrafluoroethylene (PTFE, polytetrafluoroethylene), polyimide, polyetheretherketone (PEEK, polyetheretherketone), polyamideimide, polyethylene terephthalate (PET, polyethylene terephthalate), polyethylene naphthalate, cyclohexane dimethanol terephthalate, polybutadiene-polyisoprene copolymers, polyphenylene ether, alkylated polyphenylene ether (polymers based on polyphenylene ether), or combinations comprising one or more of the above materials. Combinations of high polarity and low polarity can be used, including epoxy resin and polyphenylene ether, epoxy resin and polyetherimide, cyanate ester and polyphenylene ether {non-limiting examples include cyanate ester and polyphenylene ether}, and 1,2-polybutadiene and polyethylene.

[0089] The conveyor belt material is particularly suitable for microwave ovens and is heat-resistant. Generally, the conveyor belt material is particularly suitable for microwaves in the frequency range of 0.3 to 300 GHz, preferably 0.5 to 5.2 GHz, 0.8 to 3 GHz, 0.9 to 2.5 GHz.

[0090] The term "heat resistance" refers to the ability of a material to withstand specific thermal conditions (such as heat transfer or temperature cycling) without undergoing physical or chemical changes. As used herein, "heat resistance" shall be understood to mean that the material does not undergo significant melting, deformation, or foaming. The temperature limit is the temperature at which the properties of the material begin to change due to the temperature applied at atmospheric pressure.

[0091] Typically, the elastic outer layer 7b and at least the extraction zone 3 of the conveyor belt 1 comprise or are made of a material that is heat resistant to 300 °C at atmospheric pressure.

[0092] For example, and fluoropolymers are extremely stable at high temperatures. Polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK), and perfluoroalkoxy alkane (PFA) can be used continuously at 260 °C (500 °F), FEP can be used continuously at 205 °C (401 °F), and ETFE can be used continuously at 155 °C (311 °F) at atmospheric pressure.

[0093] Two key factors used to describe the dielectric properties that affect the performance of a material are the dielectric constant (so-called relative permittivity or ε r ) and the loss tangent (also known as the dissipation factor). The relative permittivity is the ratio of the permittivity of the material (ε) to the permittivity of free space (ε0). Here, this term measures the ability of the material to store energy when an electric field is applied. Therefore, this quantity is related to properties such as polarization or capacitance. The loss tangent quantifies the energy lost due to the variation of the electric field through the material. The lost energy tends to increase with increasing frequency. Therefore, this term represents the sum of the inherent and non-inherent dielectric losses.

[0094] The term "dielectric material" as used herein is defined as any material having a dielectric constant with a positive real part ε ′ . Generally, the term "dielectric material" refers to an electrical insulator material or a composite material of different materials that can maintain an electric field and dissipate very little power in the form of heat. By definition, a "dielectric material" is a material that has a low electrical mobility under the action of an electric field and is thus not easily polarized.

[0095] Relative permittivity: As used herein, the term "relative permittivity" refers to the ability of a dielectric material to be polarized under the action of an electric field. This term describes the ratio of the permittivity of the material to the permittivity of free space. Therefore, the so-called relative complex permittivity is expressed as a complex number, which is related to the real part and the imaginary part and exhibits temperature-frequency dependence, as shown in Equation 2.

[0096] Equation 2

[0097] where ε r= relative permittivity, ε = measured permittivity, ε0 = permittivity of free space (8.8542×10"12 F / m), ε′ = real part of the permittivity ε, and ε″ = imaginary part of the permittivity. By definition, the relative permittivity of free space is 1, and that of water is 80.1 (at 20 °C). The relative permittivity of organic coatings is typically 3 to 8. Generally, "high permittivity" refers to materials with a relative permittivity of at least 3.3. The term "low permittivity" in this article refers to materials with a relative permittivity below 3.3.

[0098] The maximum continuous operating temperature (measured according to test method ISO 2578 starting from 20,000 hours of use temperature) is preferably up to 155 °C, more preferably up to 260 °C.

[0099] The water absorption value refers to the value obtained using ASTM D570-98.

[0100] Typically, the elastic outer layer 7b includes materials with a water absorption rate below 0.03%, preferably equal to 0.0001%.

[0101] Excellent solvent resistance or very good solvent resistance refers to an "excellent" or "very good" evaluation obtained when evaluating the solvent resistance of a material according to the ASTM D543 guidelines.

[0102] The coefficient of friction value is obtained using the ASTM D3702-94 specification. Typically, the elastic outer layer 7b contains materials with a coefficient of friction below 0.4, preferably equal to or below 0.1.

[0103] Thermal conductivity is a property that describes the relative ability of a material to transfer heat. The elastic outer layer 7b preferably includes materials with a thermal conductivity below 1 W / mK, preferably below about 0.50 W / mK. In one example, the thermal conductivity of non-reinforced polyetheretherketone (PEEK) is about 0.25 W / mK.

[0104] Other materials used in the catheter may include formulations or blends of polymers, including but not limited to PTFE, polyethylene terephthalate (PET), or PEBAX.

[0105] PTFE (polytetrafluoroethylene) is a fluoropolymer with high thermal stability (up to 260 °C), chemical inertness, extremely low dielectric constant, extremely low surface coefficient of friction, and inherent flame retardancy. There is a series of homopolymer and copolymer fluoropolymers on the market, and their trade names include and

[0106] Generally speaking, the term "electrical conductor" or "conductive material" refers to any suitable material or composite material of different materials that allows the flow of electric charge. By definition, an "electrical conductor" is a material with a high free electron mobility that allows current to pass through. Usually, electrical conductor materials are metals, preferably selected from copper, steel, aluminum, lead-tin, zinc, brass, gold, silver, or mixtures thereof.

[0107] Advantageously, the electrical conductor material is stainless steel, such as AISI 304, AISI 304L, AISI 316, AISI 316L, AISI 430, or ASTM A564.

[0108] Preferably, the conveyor belt and the elastic sleeve are made of any of the following polymers, such as but not limited to fluoropolymers, or polyether ketones, or polyolefins, or mixtures thereof.

[0109] The fluoropolymer can be at least one of fluorinated homopolymers, such as but not limited to polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), ethylene-tetrafluoroethylene (ETFE), polyvinyl fluoride (PVF), or perfluoroalkoxy alkane (PFA), ethylene-tetrafluoroethylene (ETFE), polyvinyl fluoride (PVF), or perfluoroalkoxy alkane (PFA); or fluorinated copolymers, such as the copolymerization of tetrafluoroethylene (FED), tetrafluoroethylene (TFE), vinylidene fluoride (VDF), vinyl fluoride (VF), or chlorotrifluoroethylene (CTFE) with monomers or mixtures thereof. The fluoropolymer can also be selected from at least one of polyvinylidene fluoride (PVDF), tetrafluoroethylene-hexafluoropropylene (FEP), hexafluoropropylene (HFP), and perfluoropropyl vinyl ether (PPVE), or mixtures thereof.

[0110] The polyether ketone can be at least one of polyether ketone (PEK), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), or mixtures thereof, but is not limited thereto. The polyether ketone can be a copolymer, such as but not limited to PEK / PEEK, PEEK / PES (polyethersulfone), PEK / PES, or mixtures thereof.

[0111] The polyolefin can be at least one of polypropylene (PP), polyethylene (PE), olefin block copolymer (OBC), polyolefin elastomer (POE), ethylene-vinyl acetate copolymer (EVA), polybutene (PB), and polyisobutene (PIB), or mixtures thereof, but is not limited thereto.

[0112] According to Figure 5 and Figure 6 In one embodiment shown, the longitudinal edge L is provided with one or more slats 8, preferably semi-rigid or rigid slats 8, disposed between the partitions 4.

[0113] More than one slat can be arranged on each side of each extraction zone, preferably with a gap between two consecutive slats.

[0114] Advantageously, the height of the slat 8 is 0.25 to 3 times the height of the partition, preferably 0.5 to 2 times, more preferably 0.8 to 1.5 times. The slats arranged between the partitions limit the escape of the raw material but do not limit the flow of the liquid extracted from the raw material. This embodiment is particularly advantageous for processing seeds or berries.

[0115] Preferably, the semi-rigid or rigid slat 8 is made of a material with a dielectric loss tangent of less than 0.01, a dielectric constant of less than 4, and heat-resistant to 300 °C.

Claims

1. A microwave device for extracting volatile substances or liquids from organic materials by gravimetric analysis, comprising: (a) a microwave unit (2) having an inlet (2a) and an outlet (2b) for the organic material, (b) at least one conveyor belt (1) for transporting the organic material from a loading area outside the microwave unit (2) to the inlet (2a), then through the microwave unit (2) to the outlet (2b), and then to an unloading area outside the microwave unit (2), wherein the conveyor belt comprises a belt having a plurality of transverse partitions (4) on its upper surface, and a plurality of extraction zones (3) are defined between these transverse partitions (4), the extraction zones having a substantially flat surface and comprising one or preferably a plurality of drainage holes (5), wherein each transverse partition (4) has a transverse chamber (6) passing through it, and a rod (7) is accommodated in the transverse chamber, the rod extending more than half of the length of the transverse partition and more than half of the height of the transverse partition, wherein the rod (7) comprises a rigid central core (7a) which comprises a rigid electrical conductor material.

2. The device according to claim 1, wherein the rigid central core (7a) is embedded in an outer layer (7b) made of a microwave-transparent material.

3. The device according to claim 2, wherein the outer layer (7b) comprises a material having one, a plurality or all of the following properties: - a dielectric loss tangent below 0.01, - a dielectric constant below 4, and - a heat resistance up to 300 °C.

4. The microwave device according to claim 2 or 3, wherein the outer layer (7b) comprises a material having one, a plurality or all of the following properties: - a maximum continuous operating temperature (measured according to the ISO 2578 test method, with the operating temperature starting from 20,000 hours) up to 155 °C, preferably up to 260 °C, and / or - a thermal conductivity below 1 W / mK, preferably below about 0.50 W / mK, and / or - very good solvent resistance (ASTM D543), preferably equal to excellent, and / or - a water absorption rate below 0.03% (ASTM D570), preferably equal to 0.0001%, and / or - a coefficient of friction (ASTM D3702) below 0.4, preferably equal to or below 0.

1.

5. The device according to claim 1, wherein at least the extraction zones (3) of the conveyor belt (1) comprise a material having one, a plurality or all of the following properties: - a dielectric loss tangent below 0.01, - a dielectric constant below 4, and - a heat resistance up to 300 °C.

6. The device according to claim 1, wherein the drainage holes are holes having an average diameter (d) of 0.001 to 30 mm, preferably 0.01 to 20 mm.

7. The microwave device according to claim 1, wherein the ratio of the distance (dp) between two transverse partitions (4) to the length (D) between the inlet (2a) and the outlet (2b) of the microwave unit is 1 to 0.

003.

8. The microwave device according to any one of the preceding claims, wherein, The ratio h / H of the height (h) of the transverse partition (4) to the height (H) of the distance between the upper surface of the extraction zone (3) and the upper boundaries of the inlet (2a) and / or the outlet (2b) is from 0.99 to 0.

2.

9. The microwave device according to claim 1, wherein the longitudinal edges (L) comprise semi-rigid or rigid slats (8) disposed between the partitions (4).

10. The microwave device according to claim 1, wherein the semi-rigid or rigid slats (8) are made of a material having a dielectric loss tangent of less than 0.01, a dielectric constant of less than 4 and heat resistant up to 300 °C.

11. The microwave device according to claim 1, wherein the rigid central core (7a) is made of a conductive material such as copper, steel, aluminum, lead, tin, zinc, brass, gold or silver.

12. The device according to any one of the preceding claims, wherein the walls of the chamber for receiving the rod are made of the same material as the belt in the extraction zone, but without openings or holes.

13. A method for extracting a liquid composition and / or volatile substances from an organic material, comprising the step of using the device according to any one of claims 1 to 12.

14. The method according to claim 13, comprising the following steps: The organic material is conveyed from a loading zone outside the microwave unit (2) to the inlet (2a) through at least one conveyor belt (1), then through the microwave unit (2) to the outlet (2b), and then to an unloading zone outside the microwave unit (2).

15. The method according to claim 13 or 14, comprising the step of discharging the extracted liquid composition and / or volatile substances through one or preferably a plurality of discharge holes (5).

16. The method according to any one of claims 13 to 15, comprising the step of heating the organic material, for example by dielectric heating.

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