Pulse electric field processing equipment

Abstract

A pulsed electric field treatment device (1) comprising: a first electrode (2) having a first flow path (3) formed therein through which a liquid to be treated flows and which has a circular cross section; a first insulating member (4) connected to the first electrode and having a second flow path (5) formed therein which is connected to the first flow path and has a circular cross section; and a rod-shaped second electrode (6) arranged inside the first insulating member along the second flow path and on the first insulating member side of the boundary between the first electrode and the first insulating member, and a pulsed voltage is applied between the first electrode and the second electrode.

Description

[Technical Field]

[0001] The present disclosure relates to a pulsed electric field processing apparatus. [Background technology]

[0002] Electroporation is a method of treating beverages and other liquids using high-voltage pulses to electrically damage bacterial spores and achieve a sterilizing effect. Various types of electrodes are used to generate the electric field in this treatment, including opposed and coaxial types that generate an electric field perpendicular to the liquid flow direction, and butted types that generate an electric field parallel to the liquid flow direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2014-518083

[0004] The pulsed electric field generator shown in Patent Document 1 is classified as a butt-type generator, since it has electrodes with different applied voltages arranged butt-side along a flow path. As shown in this document, the electrodes are hollow and cylindrical, with an internal tubular space through which the liquid to be treated with a pulsed electric field flows. As shown in the diagram, the generator comprises a cylindrical positive electrode and ground electrodes arranged upstream and downstream of this electrode, with all electrodes electrically isolated by insulating material. This electrode arrangement creates an electric field within this space along the direction of liquid flow.

[0005] According to this conventional technology, the electric field distribution formed is such that the density of electric field lines is high and the electric field is strong in the peripheral area where the cylindrical electrode and the ground electrode are close to each other, while the density of electric field lines is low and the electric field strength is weak in the central area. This uneven electric field strength between the central and peripheral areas causes a problem in that the sterilization performance of liquids such as beverages varies between the central and peripheral areas. Summary of the Invention [Problem to be solved by the invention]

[0006] The present disclosure has been made to solve the above problems, and aims to provide a pulsed electric field treatment device that can improve the uniformity of electric field strength between the central and peripheral parts of a flow path through which a liquid to be sterilized flows, thereby reducing variation in sterilization performance. [Means for solving the problem]

[0007] The pulsed electric field processing apparatus of the present disclosure includes a first electrode having a first flow path formed therein, the first flow path having a circular cross section through which a liquid to be processed flows; End face of to In the flow direction of the liquid a first insulating member having a second flow path formed therein, the second flow path being connected to the first flow path and having a circular cross section; and a first boundary between the first electrode and the first insulating member, the first boundary being disposed within the first insulating member along the second flow path. The end surface is and a rod-shaped second electrode arranged closer to the first insulating member than the first electrode, and a pulse voltage is applied between the first electrode and the second electrode. [Effects of the Invention]

[0008] The pulsed electric field treatment device of the present disclosure includes a first electrode having a flow path for the liquid to be treated formed therein, an insulating member connected to the first electrode and having a flow path for the liquid formed therein, and a second electrode located inside the insulating member and closer to the insulating member than a first boundary between the first electrode and the insulating member. This makes it possible to increase the electric field strength in the central portion of the flow path and improve the uniformity of the electric field strength between the central portion and peripheral portion of the flow path, thereby reducing variation in sterilization treatment ability. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an overall configuration diagram of a pulse electric field processing apparatus according to a first embodiment. [Figure 2] 3 is a schematic diagram of an electric field formed in the pulse electric field processing apparatus according to the first embodiment. FIG. [Figure 3] FIG. 10 is an overall configuration diagram of a pulse electric field processing apparatus according to a second embodiment. [Figure 4] FIG. 10 is an overall configuration diagram of a pulse electric field processing apparatus according to a third embodiment. [Figure 5] FIG. 10 is an overall configuration diagram of a pulse electric field processing apparatus according to a third embodiment. [Figure 6] FIG. 10 is an overall configuration diagram of a pulse electric field processing apparatus according to a fourth embodiment. [Figure 7] FIG. 10 is an overall configuration diagram of a pulse electric field processing apparatus according to a fourth embodiment. [Figure 8] 10A and 10B are diagrams showing an electrode position adjusting member according to a fourth embodiment. [Figure 9] FIG. 10 is an overall configuration diagram of a pulse electric field processing apparatus according to a fifth embodiment. [Figure 10] FIG. 10 is an overall configuration diagram of a pulse electric field processing apparatus according to a fifth embodiment. [Figure 11] FIG. 10 is an overall configuration diagram of a pulse electric field processing apparatus according to a fifth embodiment. [Figure 12] FIG. 10 is an overall configuration diagram of a pulse electric field processing apparatus according to a fifth embodiment. [Figure 13] FIG. 13 is an overall configuration diagram of a pulse electric field processing apparatus according to a sixth embodiment. [Figure 14]FIG. 13 is an overall configuration diagram of a pulse electric field processing apparatus according to a sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Preferred embodiments of a pulsed electric field processing apparatus according to the present disclosure will be described below with reference to the drawings. The same reference numerals are used to designate the same components and corresponding parts, and detailed descriptions thereof will be omitted. While preferred embodiments of a pulsed electric field processing apparatus according to the present disclosure will be described using the sterilization of liquids as an example, the pulsed electric field processing apparatus according to the present disclosure is not limited to sterilization of liquids. The pulsed electric field processing apparatus according to the present disclosure can be used for a wide range of liquid processing applications, including, for example, extraction of cytoplasm from cells, migration of substances through cell membranes, atomization of solids in liquids, and activation of cells by cell stimulation.

[0011] Embodiment 1 1 is a diagram showing the overall configuration of a pulsed electric field processing apparatus 1 according to this embodiment. In this diagram, a first electrode 2 has a first flow path 3 formed therein through which a liquid to be sterilized flows, and the direction of the liquid flow is indicated by a hatched arrow. A first insulating member 4 connected to this first electrode 2 has a second flow path 5 formed therein that communicates with the first flow path 3. In this and subsequent embodiments, the cross-sectional shape of the liquid flow path is all circular.

[0012] A rod-shaped second electrode 6 is disposed inside the first insulating member 4 along the second flow path 5, and this second electrode 6 is disposed closer to the first insulating member 4 than the boundary (first boundary) between the first electrode 2 and the first insulating member 4. As shown by AA in FIG. 1 , this second electrode 6 is supported in the second flow path 5 by a support member 7 that supports the first insulating member 4 from the inner surface. When a pulse voltage is applied between the first electrode 2 and the second electrode 6 by the pulse power supply, an electric field is formed between the first electrode 2 and the second electrode 6 in the first flow path 3 and the second flow path 5, and the liquid flowing through these parts is sterilized by this electric field.

[0013] For example, Figure 2 shows a schematic diagram of the electric field formed when a high pulse voltage is applied to the first electrode 2 and the second electrode 6 is grounded. In the electrode structure shown in the prior art document, both the high-voltage electrode and the ground electrode have a cylindrical structure, and the density of the electric field lines formed between them is low in the center. As a result, the electric field strength is strong at the periphery of the flow path and weak in the center, resulting in non-uniformity. In contrast, with the pulsed electric field processing device 1 according to the present embodiment, electric field lines are formed toward the second electrode 6 disposed in the second flow path 5, concentrating the electric field lines near the second electrode 6, thereby increasing the electric field strength in this area. This improves the non-uniformity of the electric field distribution.

[0014] Furthermore, because the second electrode 6 is disposed closer to the first insulating member 4 than the boundary between the first electrode 2 and the first insulating member 4, the second electrode 6 can be located farther away from the first electrode 2 than in a case where the second electrode 6 extends beyond the boundary between the first electrode 2 and the first insulating member 4 and protrudes into the inside of the first electrode 2. This allows the electrical resistance between the second electrode 6 and the first electrode 2 to be relatively high, and the value of the current flowing between these electrodes to be reduced, which has the advantage of allowing the capacity of the pulsed power supply to be reduced, making it more economical.

[0015] Embodiment 2 FIG. 3 is a diagram showing the overall configuration of a pulsed electric field processing apparatus 1a according to this embodiment. Compared to the pulsed electric field processing apparatus 1 according to the embodiment, this pulsed electric field processing apparatus 1a additionally includes a mixer unit 8. As shown by BB in this figure, this mixer unit 8 has multiple blades 9, which rotate to agitate the liquid. While the mixer unit 8 is shown in FIG. 3 to be located between the first electrode 2 and the first insulating member 4, it does not necessarily have to be adjacent to the first electrode 2. It is sufficient that the mixer unit 8 be located either upstream or downstream of the first electrode 2 in the direction of liquid flow, as long as it can agitate the liquid. It may also be located upstream of the first insulating member 4 or downstream of the first electrode 2.

[0016] The pulsed electric field treatment apparatus 1a according to this embodiment is provided with a mixer unit 8 located upstream or downstream of the first electrode 2 in the direction of liquid flow. This mixer unit 8 mixes the liquid during the sterilization treatment, and can improve the uniformity of the sterilization treatment even if non-uniformity in the sterilization treatment is observed due to the electric field distribution.

[0017] Embodiment 3 4 is a diagram showing the overall configuration of a pulsed electric field processing apparatus 1b according to this embodiment. In this pulsed electric field processing apparatus 1b, a third electrode 2a is connected to the end face of the first insulating member 4 on the opposite side from the boundary where the first electrode 2 and the first insulating member 4 are connected, and a third flow path 3a leading to a second flow path 5 is formed inside. The first electrode 2 and the third electrode 2a are maintained at the same potential by, for example, connecting them externally, and a pulsed power supply applies a pulsed voltage between the first electrode 2 and the third electrode 2a and the second electrode 6, thereby forming an electric field within the pulsed electric field processing apparatus 1b.

[0018] As yet another embodiment, the overall configuration of a pulsed electric field processing apparatus 1c is shown in Fig. 5. In this pulsed electric field processing apparatus 1c, a second insulating member 4a is connected to the end face of the first electrode 2 on the side opposite the boundary (first boundary) where the first electrode 2 and the first insulating member 4 are connected, and a fourth flow path 5a leading to the first flow path 3 is formed therein. A rod-shaped fourth electrode 6a is disposed within the second insulating member 4a along the fourth flow path 5a and is disposed closer to the second insulating member 4a than the boundary (second boundary) between the first electrode 2 and the second insulating member 4a. The second electrode 6 and the fourth electrode 6a are maintained at the same potential by, for example, external wiring, and a pulsed power supply applies a pulsed voltage between the first electrode 2, the second electrode 6, and the fourth electrode 6a, thereby forming an electric field within the pulsed electric field processing apparatus 1c.

[0019] As described above, the pulsed electric field processing devices 1b and 1c according to the present embodiment can arrange electrodes at more locations than the pulsed electric field processing device 1 shown in embodiment 1, which increases the number of times the liquid passes through the electric field, thereby improving the sterilization effect of the liquid to be processed.

[0020] In addition, while Fig. 4 shows a configuration in which the first electrode 2 and the third electrode 2a are wired, and Fig. 5 shows a configuration in which the second electrode 6 and the fourth electrode 6a are wired, thereby reducing the number of power supplies, this wiring is not necessarily required. In Fig. 4, it is also possible to apply different pulse voltages between the first electrode 2 and the second electrode 6 and between the third electrode 2a and the second electrode 6 using separate pulse power supplies. On the other hand, in Fig. 5, it is also possible to apply different pulse voltages between the second electrode 6 and the first electrode 2 and between the fourth electrode 6a and the first electrode 2 using separate pulse power supplies. In this way, pulse power supply voltages can be combined to generate an electric field depending on the required sterilization ability, thereby making the sterilization treatment ability variable.

[0021] Embodiment 4 Fig. 6 shows the overall configuration of a pulsed electric field processing apparatus 1d according to this embodiment. In this pulsed electric field processing apparatus 1d, the second electrode 6b has a shape that tapers along the second flow path 5 toward the boundary between the first electrode 2 and the first insulating member 4, but the other configuration is the same as that of the pulsed electric field processing apparatus 1 according to embodiment 1. Fig. 7 shows the overall configuration of a pulsed electric field processing apparatus 1e according to this embodiment. In this pulsed electric field processing apparatus 1e, the fourth electrode 6c has a shape that tapers along the fourth flow path 5a toward the boundary between the first electrode 2 and the second insulating member 4a, but the other configuration is the same as that of the pulsed electric field processing apparatus 1c according to embodiment 3.

[0022] In the pulsed electric field processing apparatus 1d according to this embodiment, the second electrode 6b has a shape that tapers toward the boundary between the first electrode 2 and the first insulating member 4 along the second flow path 5, which has the effect of further increasing the electric field strength around the tip of the second electrode 6b. Furthermore, the opposing area between the first electrode 2 and the second electrode 6b can be reduced, which increases the resistance of both electrodes and reduces the current flowing between them. This has the advantage of allowing the capacity of the pulsed power supply to be reduced, making it more economical.

[0023] Similarly, in the pulsed electric field processing apparatus 1e according to this embodiment, the fourth electrode 6c has a shape that tapers toward the boundary between the first electrode 2 and the second insulating member 4a along the fourth flow path 5a, which has the effect of further increasing the electric field strength around the tip of the fourth electrode 6c. Furthermore, the opposing area between the first electrode 2 and the fourth electrode 6c can be reduced, which increases the resistance of these electrodes and reduces the current flowing between them. This has the advantage of allowing the capacity of the pulsed power supply to be reduced, making it more economical.

[0024] As shown in FIG. 8 , the second electrodes 6, 6b may be provided with a first electrode position adjustment member 10 that allows the position of the second electrodes 6, 6b along the second flow path 5 to be adjusted. The first electrode position adjustment member 10 adjusts the position of the second electrodes 6, 6b along the second flow path 5 by inserting a required number of washers or the like. Similarly, the fourth electrode 6c may be provided with a second electrode position adjustment member 10a that allows the position of the fourth electrode 6c along the fourth flow path 5a to be adjusted. By adjusting the positions of the second electrodes 6, 6b and the fourth electrode 6c along the flow paths in this manner, the distance between the first electrode 2 and the second electrode 6, 6b and the distance between the first electrode 2 and the fourth electrode 6c can be changed, thereby changing the electric field formed between these electrodes and enabling the formation of an electric field according to the required sterilization ability. Furthermore, because the resistance between the two electrodes can be changed, the amount of current flowing between the two electrodes can also be adjusted, thereby reducing the power supply capacity.

[0025] Embodiment 5. Fig. 9 shows the overall configuration of a pulsed electric field processing apparatus 1f according to this embodiment, and in this pulsed electric field processing apparatus 1f, the first electrode 2b has a shape in which the opening of the first flow path 3b becomes smaller along the first flow path 3b toward the boundary between the first insulating member 4 and the first electrode 2b. Fig. 10 shows the overall configuration of a pulsed electric field processing apparatus 1g according to this embodiment, and the third electrode 2c has a shape in which the opening of the third flow path 3c becomes smaller along the third flow path 3c toward the boundary between the first insulating member 4 and the third electrode 2c.

[0026] In the pulsed electric field processing apparatuses 1f and 1g of the present embodiment having the above-described features, when the first electrode 2b and the third electrode 2c are viewed from the second electrode 6 disposed in the second flow path 5, only the inwardly protruding portions of the first electrode 2b and the third electrode 2c disposed near the boundary between the first insulating member 4 and the first electrode 2b and the third electrode 2c are visible, while the wall surfaces away from the boundary are hidden by the protruding portions and become difficult to see. This means that the area where the second electrode 6 faces the first electrode 2b and the third electrode 2c is effectively reduced, thereby suppressing the current flowing between the electrodes and reducing the power supply capacity.

[0027] 11, a pulsed electric field processing apparatus 1h has a first electrode 2d formed therein with a first flow path 3d having an opening (diameter) smaller than the opening (diameter) of the second flow path 5, and a pulsed electric field processing apparatus 1i has a third electrode 2e formed therein with a third flow path 3e having an opening smaller than the opening of the second flow path 5. In these pulsed electric field processing apparatuses 1h and 1i, too, the area over which the second electrode 6 faces the first electrode 2d and the third electrode 2e is effectively reduced, thereby suppressing the current flowing between the electrodes and enabling the power supply capacity to be reduced.

[0028] 11 and 12, the first electrode 2d and the third electrode 2e are characterized in that they have rounded chamfered end faces that contact the boundary with the first insulating member 4. As described above, such pulsed electric field processing devices 1h and 1i can suppress the current flowing between the first electrode 2d and the third electrode 2e and the second electrode 6, and also can prevent fluid stagnation and allow the fluid to flow smoothly, thereby preventing the formation of pools from a hygienic standpoint.

[0029] Embodiment 6 13 is a diagram showing the overall configuration of a pulsed electric field processing apparatus 1j according to this embodiment, in which the first insulating member 4 has a first power supply portion 9a provided on an end surface of the first insulating member 4 on the side opposite to the boundary where the first electrode 2 and the first insulating member 4 are connected, and the second electrode 6 is connected to the first power supply portion 9a. If such a first power supply portion 9a were not provided, it would be necessary to provide a separate current introduction terminal that penetrates the first insulating member to supply power to the second electrode 6. However, by providing such a first power supply portion 9a, it is possible to relatively easily supply power to the second electrode 6 arranged in the second flow path 5.

[0030] FIG. 14 shows the overall configuration of a pulsed electric field processing apparatus 1k according to this embodiment, in which the first insulating member 4 has a second power supply portion 9b connected to an end face of the first insulating member 4 opposite the boundary where the first electrode 2 and the first insulating member 4 are connected, the second insulating member 4a has a third power supply portion 9c connected to an end face of the second insulating member 4a opposite the boundary where the first electrode 2 and the second insulating member 4a are connected, the second electrode 6 is connected to the second power supply portion 9b, and the fourth electrode 6a is connected to the third power supply portion 9c. If such second power supply portion 9b and third power supply portion 9c are not provided, it is necessary to separately provide current introduction terminals that penetrate the first insulating member 4 and the second insulating member 4a to supply power to the second electrode 6 and the fourth electrode 6a. However, by providing such second power supply portion 9b and third power supply portion 9c, it is possible to relatively easily supply power to the second electrode 6 arranged in the second flow path 5 and the fourth electrode 6a arranged in the fourth flow path 5a.

[0031] Although the present disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not exemplified are conceivable within the scope of the technology disclosed in this specification, including, for example, cases where at least one component is modified, added, or omitted, and cases where at least one component is extracted and combined with components of another embodiment. [Explanation of symbols]

[0032] 1, 1h, 1f, 1d, 1j, 1b, 1c, 1k, 1a: pulsed electric field processing device, 3, 3d, 3b: first flow path, 2, 2d, 2b: first electrode, 5: second flow path, 4: first insulating member, 6, 6b: second electrode, 9a: first power supply unit, 3a: third flow path, 2a: third electrode, 5a: fourth flow path, 4a: second insulating member, 6a: fourth electrode, 9b: second power supply unit, 9c: third power supply unit, 8: mixer unit

Claims

1. a first electrode having a first flow path formed therein through which the liquid to be treated flows and which has a circular cross section; a first insulating member connected to an end surface of the first electrode in a flow path direction of the liquid, the first insulating member having a second flow path formed therein and communicating with the first flow path and having a circular cross section; a rod-shaped second electrode that is disposed inside the first insulating member along the second flow path and is disposed closer to the first insulating member than the end surface that is a first boundary between the first electrode and the first insulating member; A pulse electric field processing apparatus, characterized in that a pulse voltage is applied between the first electrode and the second electrode.

2. 2. The pulse electric field processing apparatus according to claim 1, wherein the first electrode has a portion where the diameter of the first flow path is smaller than the diameter of the second flow path.

3. 3. The pulse electric field processing apparatus according to claim 1, wherein the first electrode has an end face that is in contact with the first boundary and that is rounded and chamfered.

4. 3. The pulse electric field processing apparatus according to claim 1, wherein the first electrode has a shape such that the diameter of the first flow path decreases as the first electrode approaches the first boundary along the first flow path.

5. 3. The pulse electric field processing apparatus according to claim 1, wherein the second electrode has a shape that tapers toward the first boundary along the second flow path.

6. 3. The pulse electric field processing apparatus according to claim 1, wherein the first insulating member has a first power supply portion provided on an end surface of the first insulating member opposite the first boundary, and the second electrode is connected to the first power supply portion.

7. a third electrode connected to an end surface of the first insulating member on the opposite side from the first boundary, the third electrode having a third flow path formed therein and communicating with the second flow path and having a circular cross section; 3. The pulse electric field processing apparatus according to claim 1, wherein the pulse voltage is applied between the first electrode and the second electrode and between the third electrode and the second electrode.

8. a second insulating member connected to another end surface of the first electrode on the opposite side from the first boundary, the second insulating member having a fourth flow path formed therein, the fourth flow path communicating with the first flow path and having a circular cross section; a rod-shaped fourth electrode that is disposed inside the second insulating member along the fourth flow path and is disposed closer to the second insulating member than a second boundary between the first electrode and the second insulating member; 3. The pulse electric field processing apparatus according to claim 1, wherein the pulse voltage is applied between the first electrode and the second electrode and between the first electrode and the fourth electrode.

9. the first insulating member has a second power supply portion connected to an end surface of the first insulating member opposite the first boundary, the second insulating member has a third power supply portion connected to an end surface of the second insulating member opposite the second boundary, 9. The pulse electric field processing apparatus according to claim 8, wherein the second electrode is connected to the second power supply portion, and the fourth electrode is connected to the third power supply portion.

10. 3. The pulse electric field processing apparatus according to claim 1, further comprising a mixer unit for stirring the liquid, the mixer unit being disposed either upstream or downstream of the first electrode in the direction of flow of the liquid.

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