PEF systems for processing biological materials

Abstract

The present invention describes a PEF system 1, which comprises a channel (2) for PEF treatment of a material, opposing electrode units (3), (4) and at least one conveyor belt (5), wherein the at least one conveyor belt (5) is arranged in the channel (2), between the opposing electrode units (3), (4) and close to one of these electrode units (3), (4), wherein the at least one conveyor belt (5) is perforated and / or comprises one or more PEF permeable sections, preferably perforated, more preferably a mesh.

Description

Technical Field

[0001] The invention relates to a PEF (Pulsed Electric Field) system for treating biological material, such as for example vegetables, such as carrots, salad or for example cuttings. Background Art

[0002] There are existing PEF systems for treating biological materials. For example, in WO2016 / 171610, a PEF (pulsed electric field) chamber is disclosed, which comprises a tube with two open ends, which have attachment means so that the PEF chamber can be an insertable device, wherein the tube has a length L from one open end to the other open end, and an internal width IW from one side of the tube to the other side of the tube in a cross section perpendicular to its length L, wherein the tube has a geometric narrowing of the internal width IW somewhere along the length L of the tube. In addition, in WO2017 / 184066, a PEF system similar to that described above is disclosed, however, in this case, the PEF system comprises an insertable electrode unit.

[0003] It is an object of the present invention to provide a PEF system which is capable of PEF-treating biological material in an efficient manner but at the same time at a relatively low applied voltage. Summary of the invention

[0004] The above objects are achieved by a PEF system comprising a channel for PEF treatment of a material, relative electrode units and at least one conveyor belt, wherein the at least one conveyor belt is arranged in the channel, between the relative electrode units and close to one of the electrode units, wherein the at least one conveyor belt is perforated and / or comprises one or more PEF permeable sections. According to a specific embodiment, the at least one conveyor belt is perforated. According to another specific embodiment of the present invention, the conveyor belt is a net. As can be seen in particular in the accompanying drawings, the perforated belt can be arranged as at least two conveyor belts arranged between the relative electrode units and each close to one electrode unit. Such embodiments are shown in the accompanying drawings.

[0005] The present invention provides several beneficial effects. By providing a conveyor belt as a limiter between the material to be processed and the electrode, it is possible to control the processing environment. First, hot spots with very high electric fields (e-fields) can be prevented from also providing spaces with high temperatures. This is an important aspect when providing a uniform e-field, which in turn gives the basis for a high level of control and efficiency when PEF processes materials. Secondly, the conveyor belt combined in the PEF system according to the present invention also provides an effective transmission device during processing. The material to be processed flows in a liquid (suitably an aqueous liquid) in the PEF system according to the present invention. It is important to be able to control the transmission of the material to be processed by the PEF system and reach and pass through the processing zone, i.e. between the relative electrodes. The combination of one or more conveyor belts such as according to the present invention realizes an effective way to transmit and process biological materials (e.g., carrots or cuttings) in an aqueous transmission system when PEF processes materials, i.e., to ensure a high product / water ratio. This is important because if the product / water ratio is high, it requires a lower flow rate through the machine, which requires a lower PEF power, and the solution becomes more effective, less complex and less costly.

[0006] With regard to known methods, the following should be noted. For example, in US2017 / 0035078 a method and system for producing potato chips are described, wherein whole or sliced ​​potatoes are subjected to a pulsed electric field treatment. In addition, in US2018 / 0368451 a method and system are disclosed, wherein raw fruits or vegetables are pre-treated prior to atmospheric frying, wherein the pre-treatment comprises applying a pulsed electric field to the raw product, followed by slicing and immediate blanching in an aqueous solution at a temperature above 145° F in a turbulent environment. In addition, in EP 2941968 a device for electroporating potatoes is disclosed, the device comprising a treatment chamber, the treatment chamber comprising a conveyor belt immersed in a liquid, a pulse generator and at least two electrodes mounted in or near an insulated tube wall of the treatment chamber; wherein the treatment chamber is arranged to receive a whole potato in a solid phase, which is transported through at least two electrodes with or without a liquid transport carrier.

[0007] However, the PEF system according to the present invention differs from the systems and methods of the above aspects in that the at least one conveyor belt is perforated or comprises one or more PEF permeable sections according to the present invention. This is not shown or suggested in any of the above documents. According to the present invention, the perforated portion or PEF permeable section of the at least one conveyor belt is important for providing effective PEF treatment. DETAILED DESCRIPTION

[0008] Some specific embodiments of the present invention are disclosed and further presented below.

[0009] As mentioned above, the PEF system according to the present invention comprises at least one conveyor which is perforated such as having a mesh configuration or otherwise comprises one or more PEF permeable sections. A PEF permeable section is such that the material of the conveyor allows the passage of material for PEF treatment.

[0010] As mentioned, according to one embodiment of the invention, the at least one conveyor belt is perforated, preferably a mesh. The material used in the conveyor belt should be able to be PEF treated through the material. This means that the material should be permeable, the material is so or through perforations etc. In addition, the material suitable for use is non-conductive. Furthermore, the material suitably also has a high permeability so that the PEF treated material is not shadowed, so that the treatment becomes uniform. In this context, it can be mentioned that according to one specific embodiment of the invention, the at least one conveyor belt is perforated, preferably a mesh, wherein the area of ​​the holes is at least 40% of the total area of ​​the conveyor belt.

[0011] In addition, with regard to the above, it should also be understood that the perforated portion of the at least one conveyor belt according to the present invention can be formed in many forms and arranged in different types of PEF systems according to the present invention. Firstly, the holes provided for the perforated portion can have any type of shape. Secondly, in the PEF system according to the present invention, it should be noted that any type of arrangement is possible in which opposing electrodes are provided on each side of the conveyor belt. This further means that with only one conveyor belt according to the present invention, one electrode can be arranged not to be covered by the belt or the net.

[0012] Additionally, it should be noted that different types of conveyor belts may be combined in the PEF system according to the present invention, such as where one conveyor belt is perforated and another conveyor belt comprises a PEF permeable section.

[0013] Furthermore, the holes forming the perforated portion do not have to be physical. Such PEF permeable sections can be provided by means of a conveyor belt of suitable material. As another such example, the holes can be alternative electrical holes. If the conveyor belt is made of metal, this is a possible arrangement. However, metal conveyor belts create two problems. The first problem is that the conveyor belt may pose an electrical hazard, and the second problem is that the e-field created will be less efficient. In order to overcome these problems, the conveyor belt can be arranged to have "metal sections" connected by isolation sections. If the isolation sections are sufficiently isolated, only the "metal sections" close to the electrodes will generate an e-field. Such electrical holes can also be considered as PEF permeable sections of the conveyor belt.

[0014] Additionally, the conveyor belt should also be thin to ensure that the voltage is not lost during the PEF process.Thus, according to a particular embodiment of the present invention, the at least one conveyor belt has a thickness in the range of 0.5 mm - 5 mm, preferably in the range of 0.5 mm - 2 mm.

[0015] In addition, a very suitable material for conveyor belts is a perforated thin mesh constructed from fine wires, for example having a thickness within the above ranges. Such a mesh provides all the above-mentioned suitable benefits, as well as providing a very low shielding effect when the wires used are very fine.

[0016] In addition, the channels for PEF treatment and their geometry are of interest with respect to the present invention. According to one specific embodiment of the present invention, the channels for PEF treatment of materials are longitudinal channels when viewed in cross section from one side, and wherein each of the opposing electrodes is arranged on that side of each of the channels in the channel. An example of this type of geometry is clearly shown in the accompanying drawings.

[0017] In addition, according to yet another specific embodiment of the present invention, the PEF system also comprises an inflow channel intended to receive the material to be treated, and wherein the inflow channel is in flow contact with the channel for PEF treatment of the material. These possible different flow channel portions of the common channel for inflow and treatment are shown in the accompanying drawings with some possible examples. Thus, when comparing the inflow direction with the outflow direction of the PEF system according to the present invention, it is also possible to see examples of different directions. In this context, it can be mentioned that according to a specific embodiment of the present invention, the inflow channel continues into the channel for PEF treatment of the material with a changed geometric direction, preferably wherein the inflow channel has a substantially vertical direction or an inclined vertical direction, and wherein the channel for PEF treatment of the material is inclined upwards when continuing from the inflow channel.

[0018] With regard to the geometry and orientation of the channel and the position of the relative electrodes, several aspects may be mentioned according to the invention. Firstly, the electrodes should be positioned underwater. Here, sharp channel angles can be used to provide a relatively small device. On the other hand, with sharp channel angles, such as when the inflow channel section continues into the treatment channel, there is always a clear risk that the material to be treated gets stuck. One possibility according to the invention is to combine different inner diameters when continuing from the inflow channel into the treatment channel section.

[0019] In addition, the range of the angle of inclination of the channel portion is also provided and can be a mode of optimizing according to the present invention, or at least limit the above-mentioned problem. According to a specific embodiment, the angle of inclination of the inflow channel is in the range of 30 degree-60 degree, for example, about 45 degree. In addition, according to another specific embodiment of the present invention, the angle of inclination of the processing channel or the outflow channel that may also be referred to is in the range of 15 degree-45 degree, such as about 30 degree. As can be understood above, it is suitable according to the present invention that the angle of inclination of the processing channel is lower than the angle of inclination of the inflow channel. This at least provides a slightly less sharp bend at the bottom of the whole channel.

[0020] According to a preferred embodiment, the PEF system comprises at least two conveyor belts, and wherein each conveyor belt is arranged between opposing electrode units and each is arranged close to one electrode unit. The configuration here can vary, however the most important aspect is that each conveyor belt is each arranged or "belongs" to one electrode. As can be seen in the accompanying drawings, the PEF system according to the present invention may comprise a lower conveyor belt and an upper conveyor belt. In addition, the upper conveyor belt may be arranged as the only conveyor belt for transporting the material to be treated in the inflow channel. Therefore, according to a specific embodiment of the present invention, the second conveyor belt is arranged to transport the material to be treated in the inflow channel and in the channel for PEF treatment of the material.

[0021] As will be understood above, the PEF system according to the invention may also comprise only one single conveyor belt, at least with reference to transporting the material to be treated only in the channel for the PEF treatment. Therefore, according to a specific embodiment of the invention, the PEF system comprises a single conveyor belt at a location intended for the PEF treatment. According to yet another embodiment of the invention, the single conveyor belt is arranged above a single rotating wheel. This also means that the conveyor belt is arranged around the rotating wheel without the need for an additional rotating wheel. As an example, this may be suitable when the conveyor belt is arranged as an upper conveyor belt. Therefore, according to one embodiment, the single conveyor belt is arranged as an upper conveyor belt with respect to the channel for the PEF treatment of the material. When the material to be treated floats on the surface of the liquid, the conveyor belt and the transport device are suitably arranged as an upper configuration, thereby ensuring that the material is pressed down into the liquid and / or the material pieces are pressed down so that they are organized relative to each other. This provides a more effective PEF treatment of the material.

[0022] In the single and upper conveyor arrangement according to the present invention, then, the channel for treatment can be considered to have three walls, such as an open tube or U-shaped, etc. Then, the upper conveyor is arranged as an upper unit to ensure that the material to be treated is transported along the channel. Likewise, the electrodes are fixedly arranged relative to each other to achieve PEF treatment.

[0023] With reference to the above, it can be said that providing a PEF treatment through a transport channel such as according to the invention enables lower voltage usage of the PEF generator, while the possibility of wide conveyor belts and / or wide wheels enables transport of the material to be treated.

[0024] It should be noted that the invention also embodies alternatives in which both the first conveyor belt (such as the lower conveyor belt) and the second conveyor belt (such as the upper conveyor belt) are arranged to transport material both through the inflow channel portion and through the processing channel portion (e.g. through more or less the entire channel from the inflow portion to the outflow portion). Figure 3 One such alternative is illustrated in , where the lower conveyor belt has a V-shape, and where the upper conveyor belt has a triangular shape, etc.

[0025] Furthermore, in relation to the above, it should also be noted that active transport of the material to be processed may be achieved by different means, such as by means of one or more pumps, other forms of drive mechanisms such as piston pumping, etc. This further means that in combination with a perforated conveyor belt according to the present invention, the conveyor belt may be able to transport material in different ways, not just by the way the conveyor belt itself rotates.

[0026] In addition, according to yet another specific embodiment of the present invention, at least one of the conveyor belts has a paddle. As can be seen in the accompanying drawings, when two conveyor belts are arranged, both conveyor belts appropriately have a paddle. In addition, the length and shape of the paddle can vary, such as, for example, a length in the range of 2 cm-20 cm, for example, in the range of 3 cm-15 cm. Moreover, the shape of the paddles comparable on the first conveyor belt and the second conveyor belt can be different. As an example, on the upper conveyor belt, in some cases, it may be of interest to have a paddle that is longer than the paddle arranged on the lower conveyor belt.

[0027] Furthermore, scrapers are also suitably arranged at all rollers of the belt.In addition, air knives are also beneficially incorporated on the belt to ensure removal of material back into the device.

[0028] In addition, the electrodes may have a certain configuration according to the invention. Therefore, according to a specific embodiment of the invention, wherein the relative electrodes have at least one rounded edge, preferably wherein at least the front electrode edge is rounded, preferably wherein the front electrode edge is rounded and wherein the rear electrode edge is rounded. When viewing the accompanying drawings, a possibility is shown in which both the front electrode edge and the rear electrode edge are rounded. The electrode edges are rounded in a direction perpendicular to the flow direction. This means that the material to be processed is prevented from coming into contact with the sharp electrode edges. Such electrode edges cause corner effects, which in turn form a higher risk of hot spots with high e-fields.

[0029] The PEF system according to the present invention provides several beneficial effects and solves several possible problems. The PEF system according to the present invention all provides a streamline channel, which does not have any obstacles to the material to be processed when it is forced to pass through the processing channel, and at the same time eliminates or reduces the risk of hot spots in the e-field provided between the electrodes. The latter is ensured by making the conveyor belt a certain distance from the electrodes, which in turn ensures that the biological material does not directly contact the electrodes. In addition, by also arranging the electrodes to have rounded edges, at least in the front, i.e., the rounded edges at the inflow side between the electrodes, but preferably also at the rear edge, even further reducing possible corner effects. The problem of rounded electrode edges will not eventually occur. Such problems may be higher or extreme wear of overload, loss of effect, uneven treatment or electrode corners. Such wear can provide other problems over time, such as uneven treatment or material stuck in certain positions. According to the present invention, all these problems are avoided, wherein the PEF system includes a conveyor belt to ensure a certain distance between the materials to be processed, and preferably also includes relative electrodes with rounded edges, thereby reducing potential corner effects (hot spot problems). An even controlled e-field can be obtained with the PEF system according to the invention, which also ensures an efficient flow mechanism for the material being PEF-treated between the electrodes.

[0030] Furthermore, the PEF system according to the invention is very effective for processing solid products such as carrots or cuttings etc., since these solid products can be compacted at a very high level in the processing channel, providing a uniform e-field between the opposing electrodes at the same location for the actual PEF treatment. It is also important to reduce the risk of hot spots, which could harm the cuttings or other types of materials that are intended to be processed. Furthermore, the PEF system according to the invention provides a high product / water ratio, which is possible based on several of the features mentioned above.

[0031] In addition to all the aspects mentioned above, different measurements and distances within the PEF system may also be important within the system. According to a specific embodiment of the present invention, the relative electrode unit includes at least one rounded edge having a radius in the range of 0.1-0.5 of the distance G between the relative electrode units, preferably wherein the relative electrode unit includes a front electrode edge and a rear electrode edge having a radius in the range of 0.1-0.5 of the distance G between the relative electrode units. The radius of this level with respect to the gap G between the relative electrodes is a relationship that may be of interest according to the present invention. In addition, according to another specific embodiment of the present invention, the distance G between the relative electrode units is in the range of 5cm-40cm. In addition to the gap distance, the electrode length may also be important. Therefore, according to another embodiment of the present invention, each electrode unit in the relative electrode unit has a length L, which is arranged in the longitudinal direction of the channel, and wherein the length L is in the range of 5cm-80cm. According to one embodiment, the length L is in the range of 2G-4G. In addition, as can be understood from the above, the shape of the electrodes combined according to the present invention is appropriately longitudinal, i.e., has rounded edges.

[0032] In addition, the distance between the electrode and the conveyor belt is also relevant. According to a specific embodiment of the present invention, the distance BE between the at least one conveyor belt and the electrode unit close to the at least one conveyor belt is at most 0.1G, where G is the distance between the relative electrode units, preferably at most 0.05G, more preferably at most 0.01G. Arranging the distance between the electrode and the conveyor belt ensures a uniform e-field, however, the distance should not be too large because this reduces the efficiency. As should be clear from the above, the distance BE mentioned can be the same between each electrode and the corresponding conveyor belt.

[0033] Additionally, the depth of the electrodes may also be relevant. Thus, according to a specific embodiment of the present invention, the opposing electrode unit has a depth D perpendicular to the length L, and wherein the depth D is in the range of 5 cm-100 cm, preferably in the range of 20 cm-50 cm.

[0034] Furthermore, the PEF system according to the invention may also comprise other units. One example is one or more sensors. As an example, according to one embodiment of the invention, one or more sensors are arranged which detect the volume or amount of the product to be treated. For example, when treating carrots, this can be an effective way to measure and, if necessary, change the amount of fluid flowing into the channel where the PEF treatment is carried out.

[0035] As described above, the PEF system according to the present invention has several beneficial effects. The PEF system is capable of PEF treatment of biological materials in an efficient manner but at the same time at a relatively low applied voltage. The system according to the present invention provides solutions and embodiments for handling high product density, rounded electrode edges, uniform treatment, wide conveyor belts and short distances between electrodes in one and the same inventive concept. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] exist Figure 1 1 shows a PEF system 1 according to a specific embodiment of the present invention. The PEF system 1 comprises a channel 2 for PEF treatment of materials, wherein the treatment channel 2 has opposing electrode units 3, 4. In addition, the PEF system 1 also comprises two conveyor belts 5, namely a lower conveyor belt 5a and an upper conveyor belt 5b. These conveyor belts 5a, 5b are both provided near the electrodes 3, 4. In addition, the conveyor belts 5a, 5b each have a paddle 7.

[0037] Furthermore, the PEF system 1 also comprises an inflow channel 6 intended to receive the material to be processed. Notably, the inflow channel 6 is in flow contact with the process channel 2. Furthermore, the inflow channel (6) has a substantially vertical direction continuing in an inclined vertical direction, and wherein the process channel 2 is inclined upwards while continuing from the inflow channel 6.

[0038] Furthermore, the counter-electrodes 3 , 4 have a rounded front electrode edge 10 and a rounded rear electrode edge 11 .

[0039] In addition, the distance G between the opposing electrode units 3, 4, the length L of the electrodes, and the distance BE between the conveyor belts 5a, 5b and each electrode, respectively, are also depicted.

[0040] exist Figure 2 As shown in Figure 1 A similar embodiment as shown in FIG. In this embodiment, both the lower conveyor belt 5a and the upper conveyor belt 5b are made of a mesh-based material, which is permeable as such. In addition, Figure 2 The depth D perpendicular to the length L of the electrode is shown in .

[0041] In addition, Figure 3 2 shows a further embodiment of a PEF system 1 according to the invention. In this case, the lower conveyor belt 5a is V-shaped and is arranged from the inflow channel 6 and passes through the entire process channel 2. In addition, the upper conveyor belt 5b is arranged in a triangular shape and is also arranged from the inflow channel 6 and arranged above the process channel 2.

Claims

1. A PEF system (1), comprising: A channel (2), opposing electrode units (3, 4) and at least two conveyor belts for PEF treatment of materials, wherein the at least two conveyor belts are arranged in the channel (2), between the opposing electrode units (3, 4) and close to the opposing electrode units (3, 4), wherein the at least two conveyor belts are perforated and the area of ​​the holes is at least 40% of the total area of ​​each conveyor belt, wherein the distance BE between the at least two conveyor belts and the opposing electrode units (3, 4) close to the at least two conveyor belts is at most 0.1G, wherein G is the distance between the opposing electrode units (3, 4), and wherein the front electrode edges (10) and the rear electrode edges (11) of the opposing electrode units (3, 4) are rounded.

2. The PEF system (1) according to claim 1, wherein the at least two conveyor belts are nets.

3. The PEF system (1) according to claim 1 or 2, wherein the at least two conveyor belts each have a thickness in the range of 0.5 mm - 5 mm.

4. The PEF system (1) according to claim 3, wherein the at least two conveyor belts each have a thickness in the range of 0.5 mm - 2 mm.

5. The PEF system (1) according to claim 1, wherein the channel (2) for PEF treatment of material is a longitudinal channel when viewed in cross section from one side, and wherein each electrode in the opposing electrode units (3, 4) is arranged on the side of each of the channels (2).

6. The PEF system (1) according to claim 1, wherein the PEF system (1) further comprises an inflow channel (6) intended to receive the material to be treated, and wherein the inflow channel (6) is in flow contact with the channel (2) for PEF treatment of the material.

7. The PEF system (1) according to claim 6, wherein the inflow channel (6) continues into the channel (2) for PEF treatment of material with a changed geometric direction, wherein the inflow channel (6) has a substantially vertical direction or an inclined vertical direction, and wherein the channel (2) for PEF treatment of material is inclined upwards when continuing from the inflow channel (6).

8. The PEF system (1) according to claim 1, wherein the at least two conveyor belts are two conveyor belts (5a, 5b).

9. The PEF system (1) according to claim 8, wherein the two conveyor belts (5a, 5b) are each arranged on a single rotating wheel.

10. The PEF system (1) according to claim 8 or 9, wherein one conveyor belt (5b) of the two conveyor belts (5a, 5b) is arranged as an upper conveyor belt with respect to the channel (2) for PEF treatment of material.

11. The PEF system (1) according to claim 6, wherein a second conveyor belt (5b) is arranged to transport the material to be treated in the inflow channel (6) and in the channel (2) for PEF treatment of the material.

12. The PEF system (1) according to claim 1, wherein each of said at least two conveyor belts has a paddle (7).

13. The PEF system (1) according to claim 1, wherein the opposing electrode units (3, 4) comprise at least one rounded edge having a radius in the range of 0.1-0.5 of the distance G between the opposing electrode units (3, 4).

14. The PEF system (1) according to claim 1, wherein the opposing electrode units (3, 4) include at least one rounded edge having a radius in the range of 0.1-0.5 of the distance G between the opposing electrode units (3, 4), and wherein the opposing electrode units (3, 4) include a front electrode edge (10) and a rear electrode edge (11) having a radius in the range of 0.1-0.5 of the distance G between the opposing electrode units (3, 4).

15. The PEF system (1) according to claim 1, wherein the distance G between the opposing electrode units (3, 4) is in the range of 5 cm-40 cm.

16. The PEF system (1) according to claim 1, wherein each of the opposing electrode units (3, 4) has a length L, which is arranged in the longitudinal direction of the channel (2), and wherein the length L is in the range of 5 cm-80 cm.

17. The PEF system (1) according to claim 1, wherein a distance BE between the at least two conveyor belts and the opposing electrode units (3, 4) close to the at least two conveyor belts is at most 0.05G.

18. The PEF system (1) according to claim 1, wherein the opposing electrode units (3, 4) have a depth D perpendicular to the length L, and wherein the depth D is in the range of 5 cm - 100 cm.

19. The PEF system (1) according to claim 18, wherein the depth D is in the range of 20 cm - 50 cm.

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