TWI834103B - Filtration device - Google Patents

Abstract

The filtration device 10 includes: a water tank 80 that stores the target treatment liquid; a plurality of filter units 100 that are submerged in the target treatment liquid; and a second filter chamber 35 that is arranged between the two filter units 100, and, Separate from the space containing the object treatment liquid. In the filter unit 100, the first electrode 31 is provided with a plurality of first openings 31b. The second electrode 32 is provided with a plurality of second openings 32b and is arranged to face one side of the first electrode 31 . The filter medium 34 is provided with a plurality of openings 34b and is provided between the first electrode 31 and the second electrode 32 . The first filter chamber 30 is provided in contact with the other surface of the first electrode 31 and is supplied with the target treatment liquid. The third electrode 33 is provided in the first filter chamber 30 and faces the first electrode 31 .

Description

Filtration device

The present invention relates to a filter device.

In the solid-liquid separation by filtration of a particle fluid system slurry, a method of separating particles and liquid to be separated using electroosmosis, electrophoresis, etc. is known (see, for example, Patent Documents 1 and 2). Solid-liquid separation using electroosmosis is a method of applying voltage and pressure to the filter cake layer sandwiched between electrodes, so that the moisture in the filter cake layer is removed through the filter medium through electroosmosis. In addition, solid-liquid separation using electrophoresis is a method in which the particles in the slurry are moved by electrophoresis to directly contact the filter medium to separate the particles in the slurry.

[Advanced technical documents]

[Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. Sho 61-018410

[Patent Document 2] International Publication No. 2004/045748

In the method of direct contact between the particles in the slurry and the filter medium for solid-liquid separation, it is possible to reduce the filtration speed due to clogging of the filter medium.

The purpose of the present invention is to provide a filtration device that can increase the filtration speed.

A filter device according to one aspect of the present invention has: a water tank storing a target treatment liquid; a plurality of filter units sunk into the target treatment liquid; and a second filter chamber arranged between two of the filter units. , and is separated from the space where the object treatment liquid is located; the filter unit includes: a first electrode provided with a plurality of first openings; a second electrode provided with a plurality of second openings between one side of the first electrode and The surfaces face each other and are connected to the second filter chamber; the filter medium is provided with a plurality of openings and is disposed between the first electrode and the second electrode; the first filter chamber is disposed to be connected to the second filter chamber. The other surface of the first electrode is in contact with the object processing liquid and is supplied with the object treatment liquid; and the third electrode is provided in the first filter chamber and faces the first electrode.

When the filter device of the present invention is used, the filtration speed can be increased.

10:Filtering device

13:Air diffuser

15,16: Pressurizing device

17: Pressure reducing device

20:frame

30: No. 1 filter chamber

31: 1st electrode

31a,32a: conductive thin wire

31b: Opening 1

32: 2nd electrode

32b:The second opening

33: 3rd electrode

34:Filter media

34b:Open your mouth

35: 2nd filter chamber

51: 1st power supply

52: 2nd power supply

53: 3rd power supply

70: Slurry (target treatment liquid)

71: Particles (particles of separated objects)

72:Liquid

73:Water molecules

74:Pigment protein

80:Sink

85: Discharge pipe

86:Filtrate reservoir

100,101,102,103,104,105,106,107,108: Filter unit

FIG. 1 is a schematic diagram of the filter device according to the embodiment.

Figure 2 is a schematic diagram of the filter unit of the embodiment.

FIG. 3 is a cross-sectional view schematically illustrating the structures of the first electrode, the filter medium, and the second electrode.

FIG. 4 is an equivalent circuit diagram showing the filter unit of the embodiment.

FIG. 5 is an equivalent circuit diagram showing a filter unit according to Modification 1 of the embodiment.

FIG. 6 is a schematic diagram of a filter device according to Modification 2 of the embodiment.

[Form used to implement the invention]

Hereinafter, the present invention will be described in detail with reference to the drawings. Furthermore, the present invention is not limited to the following The above-mentioned embodiments for implementing the invention (hereinafter referred to as embodiments). In addition, the structural elements in the following embodiments include those that can be easily assumed by the industry, those that are substantially the same, and those within the so-called equal range. Furthermore, the structural elements disclosed in the following embodiments can be combined as appropriate.

FIG. 1 is a schematic diagram of the filter device according to the embodiment. Figure 2 is a schematic diagram of the filter unit of the embodiment. The filtration device 10 of the embodiment is a device that separates the particles 71 from the slurry 70 (original liquid) which is a target treatment liquid in which the particles 71 are dispersed in the liquid 72 . Specifically, the filtering device 10 can be applied in the fields of life sciences, sewage treatment, drainage treatment, etc. In the field of life sciences, it can be applied to the biological industry of cultivating microorganisms such as cells, microalgae, bacteria, bacteria, viruses, etc., or culturing microorganisms to produce enzymes, proteins, polysaccharides, lipids, etc. in vitro and in vivo. It is used as an application field in the discovery of biopharmaceuticals, cosmetics industry, etc., or in the beverage industry that handles brewing, fermentation, juice extraction, beverages, etc. In the fields of sewage treatment and drainage treatment, it can be applied to the separation of biomass particles in difficult-to-filter fine biomass water system slurries. Alternatively, the filter device 10 can be used for the concentration and recovery of colloidal particles in a colloidal particle system slurry in which surface-charged particles are highly dispersed through electrical repulsion.

As shown in Figure 1, the filtering device 10 includes a water tank 80, a plurality of filter units 100, a plurality of second filter chambers 35, a discharge pipe 85, a filtrate storage tank 86, a pressure reducing device 17, an air diffuser 13, and a filter. Pressure device 15.

The water tank 80 stores the slurry (raw solution) 70 . The slurry (raw liquid) 70 stored in the water tank 80 is, for example, activated sludge. A plurality of filter units 100 are sunk into the slurry (raw liquid) 70 . The water surface of the slurry (raw liquid) 70 in the water tank 80 is above all the filter units 100 . A plurality of filter units 100 are configured to be arranged in a horizontal direction. The second filter chamber 35 is arranged between the two filter units 100 arranged in the horizontal direction. The second filter chamber 35 is separated from the space in the water tank 80 where the slurry (raw liquid) 70 is located. The gap between the two filter units 100 is sealed, thereby forming a second filter chamber 35 separated from the space in which the slurry (raw liquid) 70 is located.

The discharge pipe 85 is a pipe for discharging the filtrate liquid in the second filter chamber 35 . The discharge pipe 85 is connected to the plurality of second filter chambers 35 . The filtrate storage tank 86 is provided in the middle of the discharge pipe 85 . The filtrate collected from the plurality of second filter chambers 35 is collected into the filtrate storage 86 . The discharge pipe 85 is connected to the pressure reducing device 17 . The pressure reducing device 17 is, for example, a vacuum pump. The pressure reducing device 17 applies negative pressure to the second filter chamber 35 . Due to the pressure difference generated by the pressure reducing device 17 , the slurry (raw liquid) 70 in the second filter chamber 35 is temporarily collected in the filtrate storage tank 86 and then discharged to the outside of the water tank 80 .

The air diffuser 13 is a device that supplies air bubbles to the slurry (raw liquid) 70 . The air diffuser 13 is arranged below the filter unit 100 . The air diffuser 13 releases bubbles to the slurry (raw liquid) 70 , which rise and pass through the filter unit 100 . The pressurizing device 15 is connected to the air diffuser 13 . The pressurizing device 15 is, for example, a pressurizing pump. Driven by the pressurizing device 15, bubbles are released from the air diffuser 13 into the slurry (raw liquid) 70.

As shown in FIG. 2 , the plurality of filter units 100 includes filter unit 101 , filter unit 102 , filter unit 103 , filter unit 104 , filter unit 105 , filter unit 106 , filter unit 107 , and filter unit 108 . The filter unit 101, the filter unit 102, the filter unit 103, and the filter unit 104 are configured to be arranged in one direction X. The filter unit 105, the filter unit 106, the filter unit 107, and the filter unit 108 are configured to be arranged in one direction X. In this embodiment, one direction X is a horizontal direction. The filter unit 101 and the filter unit 105 are arranged in another direction Y that is orthogonal to the one direction X. The filter unit 102 and the filter unit 106 are configured to be arranged in the other direction Y. The filter unit 103 and the filter unit 107 are configured to be arranged in the other direction Y. The filter unit 104 and the filter unit 108 are configured to be arranged in the other direction Y. In this embodiment, the other direction Y is the vertical direction. Each filter unit 100 has a frame 20 , a first filter chamber 30 , a first electrode 31 , a second electrode 32 , a third electrode 33 , and a filter medium 34 .

The first filter chamber 30 is a space surrounded by the first electrode 31 and the third electrode 33 . The first filter chamber 30 has openings on its upper surface and lower surface in the vertical direction (direction Y) and is connected to the internal space of the water tank 80 . The slurry (raw liquid) 70 flows into the first filter chamber 30 . The first electrode 31 and the second electrode 32 are mesh-shaped electrodes. Specifically, the first electrode 31 has a plurality of conductive thin wires 31a, and a plurality of first openings 31b are provided between the plurality of conductive thin wires 31a. The second electrode 32 has a plurality of conductive thin wires 32a, and a plurality of second openings 32b are provided between the plurality of conductive thin wires 32a. The second electrode 32 is provided through the filter medium 34 and faces one side of the first electrode 31 . In other words, the filter medium 34 is provided between the first electrode 31 and the second electrode 32 . The first electrode 31 and the second electrode 32 are provided in direct contact with the filter medium 34 . The first electrode 31, the filter medium 34 and the second electrode 32 are located between the first filter chamber 30 and the second filter chamber 35. The second filter chamber 35 is isolated from the internal space of the water tank 80 by the frame 20 , but is connected to the first filter chamber 30 through the first electrode 31 , the filter medium 34 and the second electrode 32 . The plurality of conductive thin wires 31a and the plurality of conductive thin wires 32a may be metal or carbon fiber. Furthermore, the first electrode 31 and the second electrode 32 are not limited to a structure in direct contact with the filter medium 34 , and may be arranged with a gap between the filter medium 34 and the first electrode 31 .

The third electrode 33 is a plate-shaped member and is provided to face the other surface of the first electrode 31 across the first filter chamber 30 . The first electrode 31, the second electrode 32, the third electrode 33 and the filter medium 34 included in one filter unit 100 are shared with the filter unit 100 adjacent in the other direction Y. In other words, each of a first electrode 31, a second electrode 32, a third electrode 33 and a filter medium 34 is shared with the filter unit 100 adjacent in the other direction Y.

In the filter unit 101, the filter unit 103, the filter unit 105 and the filter unit 107, in one direction X (from left to right in Figure 2), the plurality of electrodes are the third electrode 33, the first electrode 31, the second electrode 32 in order. In the filter unit 102, the filter unit 104, the filter unit 106 and the filter unit 108, in one direction X (from left to right in FIG. 2), the plurality of electrodes are the second electrode 32, the first electrode 31, and the third electrode. 33 in order.

The third electrode 33 included in the filter unit 102 is shared with the filter units 103 adjacent in one direction X. The third electrode 33 included in the filter unit 106 is shared with the filter unit 107 adjacent in one direction X. In other words, between the two arranged first filter chambers 30 in one direction 107 group) are divided by the third electrode 33 shared by the group.

Furthermore, in the filter device 10, the four filter units 100 may not necessarily be arranged in one direction X. The number of filter units 100 arranged in one direction X may be less than three or more than five. In addition, the third electrode 33 arranged between two arranged first filter chambers 30 in one direction X may not necessarily be shared by the two filter units 100 . That is, in one direction X, two third electrodes 33 that are insulated from each other may be arranged between two arranged first filter chambers 30 .

A plurality of filter units 100 may also be arranged in a direction orthogonal to both the one direction X and the other direction Y (the direction toward the depth of the paper in FIG. 2 ). That is, a plurality of filter units 100 may also be configured to be arranged three-dimensionally.

The filter medium 34 includes a filter membrane 34a and an opening 34b. The filter membrane 34a is provided with a plurality of openings 34b. The electric field acts on the filter membrane 34a. For example, a microfiltration membrane (MF membrane (Microfilation Membrane)) is used as the filter medium 34 . In the embodiment, the filter medium 34 is made of an insulating material such as a resin material, and the first electrode 31 and the second electrode 32 are insulated by the filter medium 34 . Furthermore, in FIG. 2 , the first opening 31 b of the first electrode 31 , the second opening 32 b of the second electrode 32 , and the opening 34 b of the filter medium 34 are shown with the same size. However, these are only for illustration. Specifically expressed, the sizes of the first opening 31b, the second opening 32b and the opening 34b may also be different.

Moreover, the structure of the filter unit 100 shown in FIG. 2 is just an example, as long as the first filter chamber 30 sandwiched by the first electrode 31, the second electrode 32, the filter medium 34 and the third electrode 33 can be formed. , which can be of any configuration.

FIG. 3 is a cross-sectional view schematically illustrating the structures of the first electrode, the filter medium, and the second electrode. As shown in FIG. 3 , the diameter D3 of the opening 34 b provided in the filter medium 34 is smaller than the diameter D1 of the first opening 31 b of the first electrode 31 , and is smaller than the diameter D2 of the second opening 32 b of the second electrode 32 . In other words, the arrangement pitch of the plurality of conductive thin wires 31a, the arrangement pitch of the plurality of conductive thin wires 32a, and the arrangement pitch of the filter membrane 34a are set to be different from each other. For example, the diameter D1 of the first opening 31b of the first electrode 31 is 0.5 μm or more and 500 μm or less, for example, about 70 μm. The diameter D2 of the second opening 32b of the second electrode 32 is 0.5 μm or more and 1000 μm or less, for example, about 100 μm. The diameter D3 of the plurality of openings 34b provided in the filter medium 34 is preferably about 0.1 μm or more and 100 μm or less, and more preferably about 1 μm or more and 7 μm or less.

In addition, the diameter D1 of the first opening 31b of the first electrode 31 is smaller than the diameter D2 of the second opening 32b of the second electrode 32. However, it is not limited to this, and the diameter D1 of the first opening 31b of the first electrode 31 may be formed to be the same size as the diameter D2 of the second opening 32b of the second electrode 32. With this structure, the opening 34b of the filter medium 34 is set not to overlap with the plurality of conductive thin wires 31a and the plurality of conductive thin wires 32a in at least the area overlapping the first opening 31b and the second opening 32b. In addition, the distance between the first electrode 31 and the second electrode 32 is defined by the thickness of the filter medium 34 .

As shown in FIG. 2 , the filtering device 10 includes a plurality of first power supplies 51 , a plurality of second power supplies 52 , and a plurality of third power supplies 53 . The first electrode 31 is electrically connected to the second terminal 51b of the first power supply 51 . In addition, the first electrode 31 is electrically connected to the first terminal 52a of the second power supply 52. The second electrode 32 is electrically connected to the second terminal 52b of the second power supply 52 . The third electrode 33 is electrically connected to the first terminal 53a of the third power supply 53 . The second terminal 53b of the third power supply 53 and the first terminal 51a of the first power supply 51 are connected to the reference potential GND. The reference potential GND is, for example, the ground potential. However, it is not limited to this, and the reference potential GND may be a predetermined fixed potential.

FIG. 4 is an equivalent circuit diagram showing the filter unit of the embodiment. As shown in Figure 4, the 1. The power supply 51 supplies the first potential V1 with the same polarity as that of the particles 71 to the first electrode 31. The first potential V1 is -30V, for example. The second power source 52 supplies the second potential V2 having the same polarity as the particles 71 and having an absolute value greater than the absolute value of the first potential V1 to the second electrode 32 . The second potential V2 is -40V, for example. The third power supply 53 supplies a third potential V3 having a different polarity from that of the particles 71 to the third electrode 33 . The third potential V3 is, for example, +30V. The first potential V1, the second potential V2 and the third potential can be set in the range of 1 mV or more and 1000 V or less in absolute value.

As shown in FIG. 4 , the first power supply 51 and the third power supply 53 are constant voltage sources, and the second power supply 52 is a constant current source. Between the first electrode 31 and the second electrode 32, the resistance component R1 and the capacitance component C are connected in parallel. The resistance component R1 and the capacitance component C are components equivalently represented by the filter medium 34 provided with a plurality of openings 34b. Furthermore, a resistance component R2 is connected between the first electrode 31 and the third electrode 33 . The resistance component R2 is equivalent to the resistance component expressed by the slurry (raw liquid) 70 in the first filter chamber 30 .

The second power supply 52 may be a constant voltage power supply or a constant current power supply. In this embodiment, the second power supply 52 is a constant current source. Therefore, in response to the filtering state of the filter device 10, that is, in response to changes in the resistance component R1 of the filter medium 34 and the resistance component R2 of the first filter chamber 30, The second potential V2 changes. However, the polarity of the second potential V2 is the same as the polarity of the particle 71, and maintains a value greater than the absolute value of the first potential V1.

Driven by each electrode, the particles 71 are separated from the slurry (stock solution) 70 in the water tank 80 . The liquid 72 after the particles 71 are separated passes through the first electrode 31 , the second electrode 32 and the filter medium 34 , and flows to the second filter chamber 35 . The liquid 72 after the particles 71 are separated is discharged to the outside of the water tank 80 through the discharge pipe 85 .

Particles 71 are, for example, biomass particles, colloidal particles, etc., and the surface of the particles is negatively charged. Specifically, the particles 71 are sewage activated sludge in this embodiment, but they may be, for example, chlorella, microalgae Spirulina, colloidal silica, coliform bacteria, or the like. The diameter of particle 71, It differs depending on the technical field to which it is applied and the type of separation object. However, it is about 5 nm to 2000 μm, for example, about 20 nm to 500 μm.

The liquid 72 after the particles 71 are dispersed is water, and part of the water molecules 73 are positively charged. Thereby, the entire slurry (original solution) 70 is in an electrically neutralized state. The liquid 72 is not limited to water, and may also be alcohol or the like. That is, the liquid 72 only needs to be a polar solvent.

Moreover, the slurry (original solution) 70 further contains the pigment protein 74. The pigment protein 74 has the same electric charge as the polarity (negative) of the particle 71 and has a smaller particle size than the particle 71 . The pigment protein 74 has a diameter of not less than 10 nm and not more than 300 nm, for example, about 30 nm. Moreover, it is also possible to have no pigment protein74.

When the slurry (raw solution) 70 is supplied to the first filter chamber 30, a repulsive force is generated between the negatively charged particles 71 and the first electrode 31 according to Coulomb's law. Furthermore, an attractive force is generated between the negatively charged particles 71 and the third electrode 33 .

Here, Coulomb's law is expressed by the following formula (1).

F=k×(q1×q2/s ² ). ． ． (1)

Here, k is a constant, represented by k=4πε. q1 and q2 are charges, and s is the distance between charges. That is, the smaller the distance s, the greater the Coulomb force F acts on the particle 71. Specifically, the particles 71 located close to the first electrode 31 generate a relatively strong repulsive force, and the particles 71 located close to the third electrode 33 generate a relatively strong attractive force. The repulsive force and attractive force generated by the particles 71 act in the direction indicated by the arrow F1 , that is, in the direction away from the first electrode 31 and closer to the third electrode 33 . The negatively charged particles 71 move to the third electrode 33 side by electrophoresis.

Thereby, the filter device 10 can prevent the particles 71 from being accumulated on the surface of the first electrode 31 and the surface of the filter medium 34 to form a filter cake layer. That is, the filter resistance of the opening 34b of the filter medium 34 can be increased.

In addition, the positively charged water molecules 73 generate an attractive force between the positively charged water molecules 73 and the first electrode 31 . The attractive force acting on the positively charged water molecules 73 acts in the direction indicated by arrow F2, that is, in the direction from the third electrode 33 to the first electrode 31. The positively charged water molecules 73 move to the first electrode 31 side. At this time, an electric field is formed from the first electrode 31 to the second electrode 32 by the potential difference between the first electrode 31 and the second electrode 32 so as to penetrate the filter medium 34 in the thickness direction.

The water molecules 73 that move to the first electrode 31 side are forced by the electric field to be pulled to the second electrode 32 side and pass through the filter medium 34 . As the positively charged water molecules 73 move, the uncharged water molecules are also dragged to the second electrode 32 side, forming an electroosmotic flow. Thereby, the liquid 72 containing the positively charged water molecules 73 flows into the second filter chamber 35 . As mentioned above, the particles 71 are pulled away from the first electrode 31 by electrophoresis and move to the third electrode 33 side. The liquid 72 after the particles 71 are separated is discharged, thereby improving the first filter chamber. The concentration of particles 71 in the slurry (stock solution) 70 within 30.

In this way, the filter device 10 is assembled between the first electrode 31 and the third electrode 33, and uses the Coulomb force F (the repulsive force generated between the particles 71 and the first electrode 31) to move the particles 71 electrophoretically, And by utilizing the electric field between the first electrode 31 and the second electrode 32, the water molecules 73 are moved to pass through the electroosmosis of the filter medium 34, whereby the particles 71 can be separated. In addition, the first electrode 31 serves both as an electrophoresis electrode and an electroosmosis electrode. In this way, compared with the method of simply applying pressure to the slurry (original solution) 70 to separate the particles 71 with a particle size larger than the opening 34b of the filter medium 34, it is possible to suppress the formation of particles on the surface of the first electrode 31 and the filter medium 34. The surface of the filter cake layer forms a filter cake layer, which can increase the filtration speed to several times to more than 10 times.

In other words, compared with the method of simply applying pressure to the slurry (raw liquid) 70 , the degree of concentration of the particles 71 of the slurry (raw liquid) 70 in the first filter chamber 30 can be increased. In addition, the frequency of cleaning and replacement of the filter medium 34 can be reduced, and the slurry (raw liquid) 70 can be filtered efficiently. Alternatively, compared with simply applying pressure to the slurry (raw liquid) 70 to perform filtration, even if the volume of the first filter chamber 30 is reduced and the area of the filter medium 34 is reduced, the same level of filtering as before can be achieved. Filtration speed. That is, the filter device 10 can be downsized.

In addition, by controlling the electric field formed between the first electrode 31 and the second electrode 32, the particle level (particle diameter) passing through the filter medium 34 can also be controlled. For example, by applying a first potential V1=-30V to the first electrode 31 and applying a second potential V2=-40V to the second electrode 32, a shielded electric field is formed between the first electrode 31 and the second electrode 32. The pigment protein 74 having a particle size smaller than the opening 34 b of the filter medium 34 is suppressed from passing through the filter medium 34 .

That is, even when the filter medium 34 equivalent to a precision filter membrane (MF membrane) is used, the separation target can be changed by electric field control between the electrodes of the first power supply 51, the second power supply 52, and the third power supply 53. The particle diameter is equivalent to ultrafiltration membrane (UF membrane) or nanofiltration membrane (NF membrane). Ultrafiltration membrane (UF membrane) is a filtration membrane with an opening diameter of about 10nm to 100nm. Nanofiltration membrane (NF membrane) is a filtration membrane with an opening diameter of about 1 nm to 10 nm.

Furthermore, the structure of the filter device 10 described above is just an example and can be changed as appropriate. For example, a negative electrode filter plate formed by laminating the first electrode 31, the filter medium 34, and the second electrode 32, and the third electrode 33 are arranged facing each other in parallel flat plates. The negative electrode filter plate and the third electrode 33 formed by laminating the first electrode 31, the filter medium 34 and the second electrode 32 may also be formed to have curved surfaces respectively. The shape and arrangement of the negative filter plate and the third electrode 33 can be appropriately changed according to the shape and structure of the filter device 10 . In addition, the concentration of the slurry (raw liquid) 70 as the target treatment liquid supplied to the first filter chamber 30 is not particularly limited, and can be changed according to the field to which the filter device 10 is applied.

In addition, the first potential V1, the second potential V2, and the third potential V3 are preferably changed appropriately according to the type of the particles 71 to be separated, the required filtration characteristics, and the like.

The filtering device 10 does not necessarily include both the pressurizing device 16 and the pressure reducing device 17 . The filtering device 10 may also include only one of a pressurizing device 16 and a pressure reducing device 17 .

In the embodiment, a negative pressure is given to the second filter chamber 35, and the internal pressure of the second filter chamber 35 is smaller than the internal pressure of the first filter chamber 30. As an alternative, you can also use pressurized water The water surface of the tank 80 causes the internal pressure of the first filter chamber 30 to be greater than the internal pressure of the second filter chamber 35 .

The filter device 10 does not need to include the third power supply 53 . FIG. 5 is an equivalent circuit diagram showing a filter unit according to Modification 1 of the embodiment. As shown in FIG. 5 , in Modification 1 of the embodiment, the third electrode 33 is connected to the reference potential GND, for example. When the third electrode 33 is connected to the reference potential GND, compared with the case of providing a power supply to each of the first electrode 31, the second electrode 32, and the third electrode 33, the filter device 10 can be miniaturized.

The filter device 10 may not include the air diffuser 13 for supplying air bubbles to the target treatment liquid. FIG. 6 is a schematic diagram of a filter device according to Modification 2 of the embodiment. As described above, the negatively charged particles 71 move to the third electrode 33 side by electrophoresis (see FIG. 2 ). Therefore, even if the bubbles from the air diffuser 13 are not acted on, the probability that the particles 71 leave the filter medium 34 and float in the water tank 80 is high. As a result, it is difficult to form a filter cake layer that blocks the filter medium 34, and a decrease in the filtration speed can be suppressed.

As mentioned above, the filtration device 10 of this embodiment includes: the water tank 80, which stores the slurry 70 as the target treatment liquid; a plurality of filter units 100, which are submerged in the target treatment liquid; and the second filter chamber 35. It is arranged between the two filter units 100 and is separated from the space where the target treatment liquid is located. The filter unit 100 includes a first electrode 31 , a second electrode 32 , a filter medium 34 , a first filter chamber 30 , and a third electrode 33 . The first electrode 31 is provided with a plurality of first openings 31b. The second electrode 32 is provided with a plurality of second openings 32b, and is provided to face one side of the first electrode 31. The filter medium 34 is provided with a plurality of openings 34b and is provided between the first electrode 31 and the second electrode 32 . The first filter chamber 30 is provided in contact with the other surface of the first electrode 31 and is supplied with the target treatment liquid. The third electrode 33 is provided in the first filter chamber 30 and faces the first electrode 31 .

At this time, the filter unit 100 is only sunk into the target treatment liquid in the water tank 80 and operates in a state after the filter unit 100 is immersed in the target treatment liquid. Thereby, the filter unit 100 can be moved from the water tank 80 Using the slurry 70 as the target treatment liquid, the liquid 72 and the particles 71 are separated. In addition, by the Coulomb force F generated on the particles 71 between the first electrode 31 and the third electrode 33 in the first filter chamber 30 (the repulsive force generated between the particles 71 and the first electrode 31), The particles 71 move from the first electrode 31 to the third electrode 33 . This electrophoresis can suppress the formation of a filter cake layer on the surface of the first electrode 31 and the surface of the filter medium 34 . In addition, by using the electric field between the first electrode 31 and the second electrode 32 to move the water molecules 73 to pass through the electroosmosis of the filter medium 34, the particles 71 can be separated, and the slurry in the first filter chamber 30 can be improved. The concentration of the particles 71 of the material (original solution) 70. In this way, compared with the method of simply applying pressure to the slurry (raw liquid) 70 to separate the particles 71 with a particle size larger than the opening 34b of the filter medium 34, the filtration speed can be increased by several times to more than 10 times.

Furthermore, the filtration device 10 is provided below the filtration unit 100 and includes an air diffuser 13 that supplies air bubbles to the target treatment liquid.

At this time, stirring of the target treatment liquid in the water tank 80 is accelerated. In addition, the bubbles come into contact with the surface of the first electrode 31 and the surface of the filter medium 34, thereby further suppressing the formation of a filter cake layer. Therefore, the filtration device 10 of this embodiment can further increase the filtration speed.

Furthermore, the filter device 10 includes a discharge pipe 85 for discharging the filtrate liquid in the second filter chamber 35, and a pressure reducing device 17 connected to the discharge pipe 85 for imparting negative pressure to the second filter chamber.

In this case, the filtration device 10 can more easily guide the target treatment liquid from the first filtration chamber 30 to the second filtration chamber 35 compared with the situation of the water surface of the pressurized water tank 80 .

Furthermore, in the filtering device 10 and in one filter unit 100, the absolute value of the second potential V2 of the second electrode 32 is greater than the absolute value of the first potential V1 of the first electrode 31. The potential difference between the first potential V1 of the first electrode 31 and the third potential V3 of the third electrode 33 is greater than the potential difference between the first potential V1 and the second potential V2.

At this time, compared with the distance between the first electrode 31 and the second electrode 32, even if the distance between the first electrode 31 and the third electrode 33 that sandwich the first filter chamber 30 and face each other is large, the electricity will be borrowed. By swimming, the particles 71 can be moved well to the third electrode 33 side.

Furthermore, the above-described embodiments are provided to facilitate understanding of the present invention and are not intended to limit the interpretation of the present invention. The present invention can be changed/improved without departing from the spirit thereof, and equivalents of the present invention are also included.

10:Filtering device

13:Air diffuser

15: Pressurizing device

17: Pressure reducing device

30: No. 1 filter chamber

35: 2nd filter chamber

80:Sink

85: Discharge pipe

86:Filtrate reservoir

100:Filter unit

Claims (5)

A filtration device, which has: a water tank storing a target treatment liquid; a plurality of filter units sunk into the target treatment liquid; and a second filter chamber arranged between two of the filter units, and having the The target processing liquid is separated by space, and the filter unit includes: a first electrode provided with a plurality of first openings; a second electrode provided with a plurality of second openings, facing one side of the first electrode and facing one side of the first electrode; The second filter chamber is connected; the filter medium is provided with a plurality of openings and is disposed between the first electrode and the second electrode; the first filter chamber is disposed between the other side of the first electrode and The surfaces are in contact with each other and the object treatment liquid is supplied; and the third electrode is provided in the first filtration chamber and faces the first electrode. The filtration device of claim 1, which includes an air diffuser disposed below the filtration unit and supplying air bubbles to the target treatment liquid. The filter device of claim 1, which includes: a discharge pipe for discharging the filtered liquid in the second filter chamber; and a pressure reducing device connected to the discharge pipe to impart negative pressure to the second filter chamber. The filtration device of claim 2, which includes: a discharge pipe for discharging the filtered liquid in the second filter chamber; and a pressure reducing device connected to the discharge pipe to impart negative pressure to the second filter chamber. The filter device of any one of claims 1 to 4, wherein the absolute value of the second potential of the second electrode is greater than the absolute value of the first potential of the first electrode, The potential difference between the first potential and the third potential of the third electrode is greater than the potential difference between the first potential and the second potential.

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