Particle classification device and particle classification method

Abstract

To provide a particle classification device and a particle classification method.SOLUTION: A particle classification device comprises: a supply chamber 51 which supplies a suspension solution 11 in which particles are dispersed; a filtration chamber 52 which allows fine particle components in the solution to pass therethrough by an electric-field filtration action and retains a concentrated liquid of coarse particle components; and a filtrate chamber 53 which discharges, to the outside, a filtrate including the fine particle components that have passed through. The filtration chamber 52 includes: a plate-shaped anode electrode 14 disposed on a supply chamber side and having through holes; and a cathode filter plate electrode 14 disposed on a filtrate chamber 53 side, including a diaphragm 13 having pores that block negatively-charged coarse particle components and having pores.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a particle classification device and method for separating particles in a particle fluid slurry solution (suspension solution) into classes based on the particle diameter, that is, classifying particles. [Background technology]

[0002] The main organic substances produced by living biomass can be broadly classified into carbohydrates, proteins, and lipids (e.g., lecithin). The physical properties and efficacy of carbohydrates, proteins, and lipids change depending on the particle size and the amount of separation. Colloidal particles of inorganic substances such as colloidal silica and alumina also vary in industrial application, industrial utility value, and quality evaluation depending on the particle size classification.

[0003] Lecithin is labeled as "soybean phospholipid, egg yolk lecithin" in quasi-drugs and "egg yolk phospholipid" in other names for quasi-drugs, and is used as a pharmaceutical for emulsifying, dispersing, moisturizing, and improving durability (see Non-Patent Document 1: Comprehensive Report on the Cosmetic Ingredient "Lecithin"). Finely granulated (fine particle) lecithin is easily absorbed by the human body and is used as a raw material for various pharmaceutical applications. [Prior art documents] [Patent documents]

[0004] [Non-Patent Document 1] "Current status of lecithin use and the actual functions of dietary lecithin" https: / / www.jstage.jst.go.jp / article / jos1956 / 40 / 10 / 40_10_951 / _pdf Summary of the Invention [Problem to be solved by the invention]

[0005] In a typical prior art technique, to classify particles within a predetermined particle size range from a suspension solution slurry, for example, the particles are filtered using a filter medium with an average pore size of 200 nm, and the particles are separated into large and small particle classes, i.e., classified, by physical filtration to determine whether or not they pass through the average pore size of the filter medium.

[0006] However, when classifying particles using physical penetration through the pores of a filter medium, if the classification operation is carried out over a long period of time, a cake layer will form on the surface of the filter medium, and the pores of the filter medium will become clogged, causing a change in the pore diameter of the filter medium. As a result, the conventional technology has a problem in that stable classification cannot be achieved by the physical fractional filtration method in which particles are filtered out by filtering only those that pass through the pore diameter of the filter material or not.

[0007] Here, for example, the particle size distribution of lecithin, which is an example of particles, is said to be, for example, 40 to 4000 μm. For example, fine lecithin particles of 1000 nm or less (preferably 800 nm or less) are said to be well absorbed by the human body, and there is a strong demand for lecithin raw materials with a uniform particle size distribution. Therefore, there is a problem in that it is necessary to efficiently separate coarse particles from fine lecithin particles.

[0008] In view of the above problems, an object of the present invention is to provide a particle classification device and a particle classification method that are capable of fractional classification by electrofiltration and are expected to enable efficient production of high-quality fine particles. [Means for solving the problem]

[0009] The particle classification device according to the present invention comprises: a supply chamber for supplying a suspension solution in which particles are dispersed; a filter chamber that allows fine particle components in the solution to pass through by electrolytic filtration and reserves a concentrated solution of coarse particle components; a filtrate chamber for discharging the filtrate containing the permeated fine particle components to the outside, The filter chamber is a flat anode electrode having a through hole disposed on the supply chamber side; a cathode filter plate electrode having pores, the cathode filter plate electrode being disposed on the filtrate chamber side and having a diaphragm having pores for blocking coarse particle components of the negatively charged components; The present invention is characterized by comprising:

[0010] The particle classification method according to the present invention comprises: a supply chamber for supplying a suspension solution; a filter chamber that allows fine particle components in the suspension to pass through by electrolytic filtration and reserves a concentrated solution of coarse particle components; a filtrate chamber for discharging the filtrate containing the permeated fine particles to the outside, The filter chamber is a flat anode electrode having a through hole disposed on the supply chamber side; a cathode filter plate electrode having pores, the cathode filter plate electrode being disposed on the filtrate chamber side and having a diaphragm having pores for separating the negatively charged particles; Using an electrolytic filtration device comprising: The method is characterized in that fine particles and coarse particles in the suspension are classified. [Effects of the Invention]

[0011] According to the present invention, fractional classification (sorting by particle size) of a particle suspension solution with a wide particle size distribution becomes possible, thereby contributing to meeting the potential need for quality improvement. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic view of a lecithin classification device for classifying lecithin particles in a lecithin solution according to a first embodiment of the present invention. [Figure 2A] FIG. 1 is a schematic view of a lecithin classification device according to a second embodiment of the present invention. [Figure 2B] FIG. 1 is a schematic view of a lecithin classification device according to a third embodiment of the present invention. [Figure 3] An example of the relationship between particle size (nm) of lecithin in a soybean lecithin concentrate and frequency (%) is shown below. [Figure 4A] FIG. 1 shows the particle size distribution of lecithin in the filtrate. [Figure 4B] FIG. 1 shows the particle size distribution of lecithin in a lecithin concentrate. [Figure 5A] FIG. 1 shows the particle size distribution of lecithin in the filtrate. [Figure 5B] FIG. 1 shows the particle size distribution of lecithin in a lecithin concentrate. [Figure 6A] FIG. 2 is a schematic view of another lecithin classification device according to the first embodiment of the present invention. [Figure 6B] FIG. 2 is a schematic view of a filter plate electrode of another lecithin classification device according to the first embodiment of the present invention. [Figure 6C] FIG. 2 is a schematic diagram of a flat anode electrode of another lecithin classification device according to embodiment 1 of the present invention. [Figure 6D] FIG. 2 is a schematic view of a filter medium of another lecithin classification device according to the first embodiment of the present invention. [Figure 7] 1 is a schematic diagram of a poling treatment of a high dielectric constant coating layer according to the present invention; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to the following modes for carrying out the invention (hereinafter referred to as embodiments). Furthermore, the components in the following embodiments include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the components disclosed in the following embodiments can be combined as appropriate. In the embodiments of this specification, the same components are denoted by the same reference numerals throughout. Note that this embodiment is merely an example that embodies the configuration of the present invention, and various design changes can be made without departing from the scope of the claims.

[0014] [Embodiment 1] An embodiment of the particle classification device of the present invention will be described below using a classification device for lecithin as an example of an object to be classified. As for organic substances, in addition to lipids (lecithin), for example, carbohydrates and proteins can also be applied, and as for inorganic substances, colloidal particles such as colloidal silica, alumina, and barium titanate can also be applied.

[0015] FIG. 1 is a schematic diagram of a lecithin classification device for classifying lecithin particles in a lecithin solution according to a first embodiment of the present invention. The lecithin classification device 100 according to the first embodiment is a device (electrolytic filtration device) that classifies lecithin in a lecithin solution.

[0016] As shown in FIG. 1, the lecithin classification device 100 of the first embodiment includes a supply chamber 51 that supplies, as a supply liquid, a lecithin solution (suspension solution) 11 in which lecithin particles having a particle size distribution are dispersed, and a filtrate chamber 53 that retains coarse lecithin particles among the lecithin particles that are negatively charged by electrofiltration as a concentrated liquid 11B in a filtration chamber 52 and discharges a filtrate 11A containing lecithin fine particles to the outside. The filter chamber 52 is equipped with a flat anode electrode 60 having through holes 60a (hole diameter: 0.5 mm to 2.0 mm) arranged on the supply chamber 51 side, a diaphragm (filter material) 13 having pores 13a (pore diameter: 0.2 mm or less) for separating anionic components arranged on the filtrate chamber 53 side, a cathode filter plate electrode 14 having pores 14a (pore diameter: 0.1 μm or more and 5000 μm or less), and a discharge section 52a for discharging the concentrated liquid 11B of lecithin coarse particles. The filtrate chamber 53 is provided with a filtrate discharge part 53a for discharging the filtrate 11A containing the lecithin fine particles.

[0017] The cathode filter plate electrode 14 is composed of a cathode first electrode 14A and a cathode second electrode 14B, and further, a diaphragm (filter plate) 13, which is an insulator having pores 13a, is sandwiched between the cathode first electrode 14A and the cathode second electrode 14B. Here, the diaphragm 13 is made of an insulating material, and may be, for example, a nonwoven fabric made of fibers such as PP (polypropylene), PE (polyethylene), NY (nylon), cellulose, or the like.

[0018] The filter chamber 52 contains a first power source 41 electrically connected to the flat anode electrode 60 and the cathode first electrode 14A, and a second power source 42 electrically connected to the cathode first electrode 14A and the cathode second electrode 14B. Here, the electrode configuration is such that the cathode second electrode 14B is at a first potential (V1=10V), the cathode first electrode 14A is at a second potential (V2=20V), and the flat anode electrode 60 is at a third potential (V3=30V), resulting in an absolute potential difference of 20V. The absolute value of the cathode potential supplied from the second power source 42 increases as the distance from the filter chamber 52 increases (V2 (20V)>V1 (10V)).

[0019] The electrode configuration is not limited to the configuration shown in FIG. 1. Alternatively, the cathode first electrode 14A may be earthed, the cathode first electrode 14A may be used as a reference electrode, the potential (V2) of the cathode first electrode 14A may be set to 0 V, the potential (V1) of the cathode second electrode 14B may be set to -10 V, and the potential (V3) of the flat anode electrode 15 may be set to +10 V, and the absolute value of the voltages may be changed while the potential difference between them remains unchanged.

[0020] Here, a cathode electric field Ec is generated between the first cathode electrode 14A and the second cathode electrode 14B. The cathode electric field Ec exerts a repulsive force that inhibits the migration of coarse lecithin particle components among the negatively charged lecithin particles from the filtration chamber 52 to the filtrate chamber 53.

[0021] Furthermore, the cathode electric field Ec generated between the cathode first electrode 14A and the cathode second electrode 14B exerts a force that draws polarized water molecules from the filtration chamber 52 toward the filtrate chamber 53. This causes an electroosmotic flow in which polarized water molecules are drawn toward the filtrate chamber 53 (see arrow F1 in FIG. 1). Therefore, the water in the filtration chamber 52 moves at a faster rate than when it moves to the filtrate chamber 53 simply under the filtration pressure of a pump or the like. Therefore, the amount of water moving from the filtration chamber 52 to the filtrate chamber 53 per unit time increases.

[0022] Then, the filtrate 11A that has moved to the filtrate chamber 53 is discharged to the outside from the filtrate discharge portion 53a of the filtrate chamber 53 due to the filtration pressure. The lecithin solution 11 from which the filtrate 11A has been separated in the filter chamber 52 is concentrated inside the filter chamber 52 due to the separation of the filtrate 11A, and is discharged to the outside from the discharge part 52a of the filter chamber 52 as a concentrated solution 11B of coarse lecithin particles due to the filtration pressure.

[0023] Here, the filtration pressure by the supply pump (not shown) is preferably set so that the pressure (gauge pressure) in the supply chamber 12, which is an enclosed space, is slightly higher than atmospheric pressure, for example, 0.005 MPa or more and 0.5 MPa or less, preferably 0.02 MPa or more and 0.1 MPa or less.

[0024] The cathode filter plate electrodes 14 (cathode first electrode 14A, cathode second electrode 14B) are provided with a plurality of holes 14a penetrating in the left-right direction in the figure. Water in the supply liquid (lecithin solution) 11 moves through the pores 14a of the electrodes 14. The diameter of the holes 14a in the cathode first electrode 14A and the cathode second electrode 14B is, for example, 0.1 μm or more and 5000 μm or less, and more preferably 100 μm or more and 1000 μm or less. Note that the diameters of the holes 14a in the cathode first electrode 14A and the cathode second electrode 14B do not have to be the same.

[0025] Furthermore, an electrolytic corrosion prevention layer (not shown) is provided on the surfaces of the cathode filter plate electrode 14 (first cathode electrode 14A, second cathode electrode 14B) and the flat anode electrode 60.

[0026] Examples of the electrolytic corrosion prevention layer include an insulating coating layer and a conductive precious metal layer. Examples of materials for the electrolytic corrosion prevention layer include, but are not limited to, titanium, aluminum, magnesium, and tantalum. Examples of materials for the conductive precious metal layer include, but are not limited to, platinum, gold, and palladium. The thickness of the electrolytic corrosion prevention layer, in the case of an insulating coating layer, is preferably, for example, about 5 μm to 30 μm, more preferably about 5 μm to 10 μm. Furthermore, the thickness of the conductive precious metal layer, such as platinum, gold, or palladium, is preferably, for example, about 0.5 μm to 10 μm, more preferably about 1 μm to 5 μm. This electrolytic corrosion prevention layer inhibits surface corrosion of the cathode filter plate electrode 14 and the flat anode electrode 60. Furthermore, because the cathode filter plate electrode 14 and the flat anode electrode 60 have an insulating coating layer, they do not come into contact with the liquid constituting the supply liquid 11. As a result, even if a potential is applied to the cathode filter plate electrode 14 and the flat anode electrode 60, electrolysis is unlikely to occur between the surfaces of the cathode filter plate electrode 14 and the flat anode electrode 60 and the liquid.

[0027] The cathode first electrode 14A faces the flat anode electrode 60 across the filter chamber 52. The distance D1 between the cathode first electrode 14A and the flat anode electrode 60 is, for example, 0.1 mm or more and 100 mm or less, and more preferably 0.1 mm or more and 40 mm or less.

[0028] The distance D2 between the first cathode electrode 14A and the second cathode electrode 14B is not particularly limited, but is, for example, 0.1 mm to 20 mm, more preferably 0.1 mm to 2 mm. Note that the smaller the distance D2 between the first cathode electrode 14A and the second cathode electrode 14B, the stronger the strength of the cathode electric field Ec generated between the first cathode electrode 14A and the second cathode electrode 14B.

[0029] Diaphragm 13 can be made of, for example, cellulose such as filter paper (membrane) or nanofiber, but the present invention is not limited to this. Taking filter paper as an example, the pore size is approximately 1 micron (a pore diameter 1000 times larger than 1 nanometer). Since water molecules are sub-nanometers in size, water can easily pass through diaphragm 13. As a result, the pump that pumps supply liquid 11 into supply chamber 12 allows water to freely pass through diaphragm 13.

[0030] In contrast, when negatively charged particles (lecithin particles) approach the cathode first electrode 14A on the cathode side, the negative electrode and the negatively charged particles (lecithin particles) repel each other due to Coulomb's repulsive force, and the particles cannot pass through the cathode first electrode 14A. Conversely, when positively charged particles approach the anode electrode 60 side of the anode plate, the positive electrode and the positively charged particles repel each other due to Coulomb's repulsive force.

[0031] As mentioned above, filter paper can be used as the diaphragm 13, but it is more preferable to use a diaphragm having a dielectric effect. The diaphragm having a dielectric effect is made of an insulating material, and for example, a nonwoven fabric using fibers such as PP (polypropylene), PE (polyethylene), NY (nylon), or cellulose may be used. In this way, by placing the diaphragm 13 having a dielectric effect between the first cathode electrode 14A and the second cathode electrode 14B, the strength of the cathode electric field Ec acting between the first cathode electrode 14A and the second cathode electrode 14B increases. The diameter of the pores 13a is preferably, for example, 0.2 mm or less.

[0032] The present invention is characterized in that, in the filter chamber 52, the cathode first electrode 14A blocks anionic components, and the lecithin concentrate 11B is discharged to the outside from the discharge section 52a, while water permeates the diaphragm 13 that constitutes the cathode filter plate electrode 14.

[0033] As a result, a lecithin solution 11 containing lecithin particles with a wide particle size distribution is introduced into the filter chamber 52 of the lecithin classification device 100, and an electric field is applied under specified conditions to separate the filtrate 11A from the filter chamber 52 into the filtrate chamber 53, leaving a lecithin concentrate 11B in the filter chamber 52.

[0034] As explained above, the actions and effects within the filter chamber 52 of the separation device of this embodiment can be considered as follows. Water, a polar solvent in the lecithin solution 11, behaves positively, and the water in the lecithin concentrate 11B in the filter chamber 52 is drawn toward the filtrate 11A (electroosmotic dehydration). Furthermore, negatively charged particles are attracted to the positive electrode due to Coulomb attraction. Water, a polar solvent, also behaves as if it were a positive charge (electrophoresis). The harmony of the three forces mentioned above—Coulomb repulsion, electrophoresis, and electroosmosis—makes it possible to separate lecithin particles.

[0035] In the classification operation of the electrofiltration method using an electrofiltration device, it is possible to use a membrane (filter material) with an average pore size larger than the maximum particle size in the particle size distribution of the suspension slurry. By applying a predetermined voltage corresponding to the classification operation to a membrane (filter material) with a large average pore size, it is possible to adjust the magnitude of the Coulomb repulsion with the negatively charged suspended particles. When a suspension slurry containing fine and coarse particles dispersed in a liquid is supplied to an electrolytic filtration device, the fine particles in the suspension slurry, along with the filtrate 11A, easily pass through the applied diaphragm (filter material) 13 with a large average pore size. On the other hand, the coarse particles are prevented from passing through the applied diaphragm (filter material) 13 with a large average pore size, making classification possible.

[0036] I changed the half-width characters to full-width characters. In the classification operation using the electrofiltration method, a diaphragm (filter material) 13 having an average pore size larger than the maximum particle size in the particle size distribution in the suspension slurry is used, which prevents the pore size of the diaphragm (filter material) 13 from being physically blocked by particles, making it possible to perform stable classification operations over long periods of time.

[0037] Furthermore, the Coulomb repulsion generated on the surface of the membrane (filter material) 13 suppresses the formation of a cake layer due to the adhesion of particles to the surface of the membrane (filter material) 13, making it possible to carry out stable classification operations over long periods of time.

[0038] As a result, it becomes possible to fractionate and classify (sort by particle size) the lecithin aqueous solution (suspension solution) 11 having a wide particle size distribution, which can contribute to meeting the potential need for quality improvement.

[0039] In this embodiment, electrodes having high dielectric constant coating layers 14b, 60b such as PVDF formed thereon can be used for the cathode filter plate electrode 14 (first electrode 14A, second electrode 14B) and the flat (perforated) anode electrode 60, as shown in FIGS. 6A, 6B, and 6C. PVDF is an abbreviation for polyvinylidene difluoride, a type of fluororesin. Because PVDF is an insulating layer with a high dielectric constant, it is possible to construct an "electrostatic field model" that exhibits the behavior of a capacitance (capacitor) between these electrodes.

[0040] By using the electrodes of the "electrostatic field model" as in this embodiment, the current flowing between the electrodes (between the second electrode 14B and the first electrode 14A, and between the first electrode 14A and the flat anode electrode 15) becomes almost zero. As a result, no electrolysis occurs, and electrolytic corrosion of the electrodes is suppressed. In addition, there is no change in the pH of the solution, and no Joule heat is generated. As a result, there is no change in the substance to be separated or the liquid quality due to pH shift or thermal denaturation. Therefore, there is no pH shift for the lecithin component. In addition, Joule heat is not generated, so there is no thermal denaturation and the components do not solidify.

[0041] Examples of other materials with a high relative dielectric constant that have insulating and dielectric properties similar to those of the above-mentioned PVDF include the following. 1) P(VDF-TrFE): Poly(vinylidene fluoride-trifluoroethylene) 2) P(VDF-CTFE): Poly(vinylidene fluoride-chlorotrifluoroethylene) 3) Polyamide 11 (Nylon (registered trademark) 11) 4) PTFE: Polytrifluoroethylene 5) Liquid crystalline ferroelectric polymers 6) MXene / PVDF composite Here, MXene is a general term for composite atomic layer compounds made of early transition metals (such as titanium and vanadium) and light elements (carbon or nitrogen), and has a sheet-like structure similar to graphene.

[0042] Examples of methods for forming the high-dielectric-constant coating layers 14b and 60b include the following. 1) A coating layer of a predetermined thickness is formed on the surface of the electrode using PVDF by electrostatic spraying or powder sintering. 2) A coating layer of a predetermined thickness is formed on the surface of the electrode by screen printing or inkjet printing with PVDF ink. 3) A PVDF film (for example, 7-200 μm) is vacuum laminated and solution cast to form a coating layer of a predetermined thickness on the surface of the electrode. 4) A PVDF solution is prepared, and a coating layer of a predetermined thickness is formed on the surface of the electrode by dipping.

[0043] After forming the coating layer, the high-dielectric-constant coating layer is subjected to a poling treatment (dipole alignment treatment). This poling treatment involves applying an external electric field, such as corona discharge, to the coating layer, aligning the molecular orientation and the random orientation of electric dipoles in a direction perpendicular to the electrode plane, as shown in Figure 5. By performing the poling treatment, high dielectric polarization can be generated in the high-dielectric-constant coating layer when a voltage is applied.

[0044] By using a lecithin classification device made up of this poled ferroelectric thin film, the longer the distance between the electrodes, the more accurate the classification. Furthermore, in the case of poled electrodes, the voltage can be increased significantly, which accelerates the electrophoretic speed, thereby achieving high classification accuracy in a short time.

[0045] The electrode in which a platinum coating layer (corrosion-resistant layer) is formed on the surface of the titanium electrode mentioned above is a "conductive electric field model." When using this "conductive electric field model" electrode, the electrolyte (cation, H + , anion, OH - ) through which an electric current flows between the electrodes.

[0046] If the "conductive electric field model" electrodes are used, electrolysis occurs, generating hydrogen and oxygen at both electrodes. Electrolytic corrosion of the electrodes occurs, so as a countermeasure, it is necessary to coat the electrode surface with, for example, platinum, as mentioned above. Furthermore, the pH of the solution changes, generating Joule heat.

[0047] In addition, the force acting on particles (electric field strength) and the particle movement speed (electrophoretic speed) are almost the same in the ``conductive electric field model'' composed of an electrode with a platinum coating on the surface of, for example, a titanium electrode, and the ``electrostatic electric field model'' composed of an electrode with a thin film coating layer with a high dielectric constant such as PVDF (for example, layer thickness of 1 μm to 100 μm) applied to the surface of a conductive electrode such as stainless steel, copper, or carbon.

[0048] Here, the electrostatic field model is configured with an electrode 14 consisting of a first electrode 14A and a second electrode 14B equipped with a filter medium, and a flat anode electrode 60 as well.

[0049] This electrostatic field model electrode configuration eliminates electrolysis and therefore eliminates gas generation (bubble generation) near the electrodes. As a result, there is no turbulence near the electrodes during classification, which improves classification accuracy.

[0050] A surface treatment method for the diaphragm (filter material) 13 will be described.

[0051] In this embodiment, as shown in FIGS. 6A and 6D, a surface treatment layer 13b (direct fluorination treatment) using fluorine gas may be formed on the diaphragm (filter material) 13.

[0052] Here, the surface treatment using fluorine gas utilizes the extremely high reactivity of fluorine gas to improve the surface characteristics of the filter medium 13. In other words, fluorine gas is brought into contact with the filter medium 13, which is the base material, to chemically modify the surface of the base material.

[0053] By applying this fluorine treatment to the surface of the material of the filter medium 13, it is possible to give the material electrical surface properties similar to those of PVDF (Polyvinylidene DiFluoride) or PTFE (Polytetrafluoroethylene), etc. As a result, the material exhibits a dipole orientation effect when electricity is applied.

[0054] [Embodiment 2] FIG. 2A is a schematic diagram of a lecithin classification device according to a second embodiment of the present invention. 2A, the lecithin classification device (electrolytic filtration device) 100A of the second embodiment is the same as the separation device 100 of the first embodiment shown in FIG. 1, except that it further includes a supply tank 61 for supplying the lecithin solution 11 as a supply liquid, a supply line L1 for supplying the lecithin solution 11 from the supply tank 61 to the supply section 51a of the supply chamber 51, a first discharge line L2 for discharging the filtrate 11A from the filtrate discharge section 53a of the filtrate chamber 53 to an external filtrate tank 62, and a second discharge line L3 for discharging the lecithin concentrate 11B from the discharge section 52a of the filtration chamber 52 to the outside. In FIG. 2, the symbol 61a denotes a stirrer, P-1 and P-2 denote liquid feed pumps, V1 to V3 denote gas vent valves, and V 11 From V 13 indicates the on-off valves.

[0055] As shown in FIG. 2A, lecithin solution 11 is introduced from supply tank 61 into filter chamber 52 of the electrolytic filtration device, and an electric field is applied under predetermined conditions appropriate for the classification operation to separate filtrate 11A containing lecithin fine particle components from filter chamber 52 into filtrate chamber 53, leaving lecithin concentrate 11B containing negatively charged lecithin coarse particles in filter chamber 52. This separated lecithin concentrate 11B is introduced into concentrate tank 63. As a result, the fine particles contained in the lecithin solution 11, which is a suspension, would normally be prevented from moving if a sufficient voltage is applied, but when a predetermined voltage corresponding to the classification operation is applied, the electric field is broken and the particles are discharged into the filtrate chamber 53 together with the filtrate 11A. That is, the lecithin fine particles in the lecithin solution 11 are carried along with the movement of the water in the filtrate 11A and pass through.

[0056] [Embodiment 3] FIG. 2B is a schematic diagram of a lecithin classification device according to a third embodiment of the present invention. As shown in Fig. 2B, the lecithin classification device (electrolytic filtration device) 100B of the third embodiment is the same as the separation device 100A of the second embodiment shown in Fig. 2A, except that a second discharge line L3 that discharges the lecithin concentrate 11B from the discharge portion 52a of the filtration chamber 52 is connected to the supply tank 61, and the discharged lecithin concentrate 11B is returned to the lecithin solution 11. In this way, the lecithin concentrate 11B is circulated and concentrated.

[0057] [Test example] The results of a test in which fine particles and coarse particles were separated from a lecithin solution 11 using the lecithin classification device 100 shown in FIG. 1 will be described. FIG. 3 shows an example of the relationship between the particle size (nm) of lecithin in a soybean lecithin concentrate, which is the lecithin solution 11, and the frequency (%). As shown in FIG. 3, the particle size distribution of the lecithin in the soybean lecithin solution 11 was found to be broad, ranging from about 80 nm to about 1800 nm.

[0058] The diaphragm (filter material) used here has an average pore size of 4000 nm, which is approximately 2.2 times the maximum particle size of lecithin, making it a diaphragm (filter material) with a sufficiently large pore size.

[0059] Therefore, the lecithin solution 11 was classified using a lecithin classification device 100 shown in FIG. The filtration conditions at this time were 120 kg / h / m 2 The voltage applied to the filter chamber 52 was 60V, and the voltage applied to the cathode filter plate electrode 14 was 30V. The test results are shown in Figures 4A and 4B.

[0060] Fig. 4A is a diagram showing the particle size distribution of lecithin in filtrate 11A, and Fig. 4B is a diagram showing the particle size distribution of lecithin in lecithin concentrate 11B.

[0061] As shown in FIG. 4A, the particle size distribution of the fine particle side of the lecithin in the filtrate 11A was a normal distribution curve with a peak at about 120 nm.

[0062] Furthermore, as shown in FIG. 4B, the particle size distribution of the lecithin in the concentrated solution 11B on the coarse lecithin particle side was a distribution curve having a peak near 700 nm.

[0063] The test conditions were as follows: filtration flow rate of lecithin solution 11 was 120 kg / h / m 2 to 180 kg / h / m 2 The flow rate (filtration rate) was changed and a classification test was conducted. The test results are shown in Figures 5A and 5B.

[0064] As shown in FIG. 5A, the particle size distribution of the lecithin fine particle side in the filtrate 11A was a normal distribution curve with a peak at about 450 nm.

[0065] Furthermore, as shown in FIG. 5B, the particle size distribution of the lecithin in the concentrated solution 11B on the coarse lecithin particle side was a distribution curve having a peak near 800 nm.

[0066] When the filtration rate is increased, slightly larger coarse particles are entrained along with the fine particles in the filtrate 11A. The distribution of the lecithin concentrate 11B (Fig. 5B) shows a clean normal distribution curve because the small particles are removed.

[0067] As a result, the filtration conditions were set at 120 kg / h / m 2 to 180 kg / h / m 2 By changing the temperature to

[0068] The distribution ratio of fine particles to coarse particles is 120 kg / h / m 2 In the case of , the ratio was 20 (fine grains) / 80 (coarse grains). In contrast, the filtration conditions are 180 kg / h / m 2 In this case, the distribution ratio was 30 (fine particles) / 70 (coarse particles), resulting in an increase in the turbidity of the filtrate 11A. This resulted in a decrease in yield, but a classification curve with a normal distribution curve of uniform particle size was obtained.

[0069] In addition to changing the filtration flow rate, a similar effect can be achieved by weakening the applied voltage. For example, by reducing the voltage applied to the filter chamber 52 from 60 V to approximately 30 to 50 V and the voltage applied to the cathode filter plate electrode 14 from 30 V to approximately 15 to 25 V, a classification effect according to a normal distribution curve can be obtained, although the separation efficiency will decrease. Conversely, when the applied voltage is increased, the intrusion of coarse particles into the filtrate side is prevented, and a filtrate containing fine particles can be obtained. [Industrial Applicability]

[0070] The present invention can be generally applied to particle classification devices and particle classification methods for classifying particles in a particle suspension solution. [Explanation of symbols]

[0071] 100 Lecithin classification device (electrolytic filtration device) 11 Lecithin solution (suspension solution) 11A Filtrate 11B Lecithin Concentrate 13 Diaphragm (filter material) 14 Cathode filter plate electrode 51 Supply room 52 Chamber 53 Filtrate chamber 60 Flat anode electrode

Claims

1. a supply chamber for supplying a suspension solution in which particles are dispersed; a filter chamber that allows fine particle components in the solution to pass through by electrolytic filtration and reserves a concentrated solution of coarse particle components; a filtrate chamber for discharging the filtrate containing the permeated fine particle components to the outside, The filter chamber is a flat anode electrode having a through hole disposed on the supply chamber side; a cathode filter plate electrode having pores, the cathode filter plate electrode being disposed on the filtrate chamber side and having a diaphragm having pores for blocking coarse particle components of the negatively charged components; A particle classification device comprising:

2. a supply tank for supplying the suspension; a supply line that supplies the suspension from the supply tank to the supply chamber; a first discharge line for discharging the filtrate from the filtrate discharge portion of the filtrate chamber to the outside; a second discharge line for discharging the concentrated liquid containing the coarse particle components from the discharge portion of the filter chamber to the outside; 2. The particle classification device according to claim 1, further comprising:

3. 3. The particle classification device according to claim 2, wherein a second discharge line for discharging a concentrated solution containing coarse particle components from the discharge portion of the filter chamber is connected to the supply tank, and the discharged concentrated solution containing coarse particle components is returned to the supply tank side.

4. 2. The particle classifying apparatus according to claim 1, wherein a surface treatment layer using fluorine gas is formed on the surface of said diaphragm.

5. 2. The particle classification device according to claim 1, wherein a coating layer having a high dielectric constant is formed on the surface of each of said cathode filter plate electrode and said flat anode electrode.

6. 6. The particle classifying apparatus according to claim 5, wherein the high dielectric constant coating layer is subjected to a poling treatment.

7. a supply chamber for supplying a suspension solution; a filter chamber that allows fine particle components in the suspension to pass through by electrolytic filtration and reserves a concentrated solution of coarse particle components; a filtrate chamber for discharging the filtrate containing the permeated fine particles to the outside, The filter chamber is a flat anode electrode having a through hole disposed on the supply chamber F side; a cathode filter plate electrode having pores, the cathode filter plate electrode being disposed on the filtrate chamber side and having a diaphragm having pores for separating the negatively charged particles; Using an electrolytic filtration device comprising: A method for classifying particles, comprising classifying fine particles and coarse particles in the suspension solution.

8. The flow rate of the supply liquid for supplying the suspension solution is varied, 5. The method for classifying particles according to claim 4, wherein the ratio of fine particles and coarse particles in the suspension to be classified is changed by electrolytic filtration.

9. The voltage applied to the filter chamber and the voltage applied to the cathode filter plate electrode are varied, 5. The method for classifying particles according to claim 4, wherein the ratio of fine particles and coarse particles in the suspension to be classified is changed by electrolytic filtration.

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