Filtration device, filtration system, and filtration method

Abstract

In order to achieve efficient filtration, the present invention includes: a first liquid holding part (101) that holds a liquid, the first liquid holding part (101) having a first hole (411) in the bottom surface thereof and a second hole (421) in a surface other than the bottom surface; a second liquid holding part (201) that communicates with the first liquid holding part (101) via the first hole (411); and a third liquid holding part (301) that communicates with the first liquid holding part (101) via the second hole (421). A first filter (412) is provided to the first hole (411), and a second filter (422) is provided to the second hole (421).

Description

Filtration device, filtration system, and filtration method

[0001] The present invention relates to a filtration device, a filtration system, and a filtration method.

[0002] With the development of nano- and micro-technology, there are industries that use particles ranging in size from tens of nanometers to hundreds of micrometers. For example, fine particles are used in automobile paints and cosmetics. Microscopic observation is used to evaluate and inspect such fine particles in solutions. Furthermore, electron microscopes with sufficient resolution are often used to evaluate particles in detail. Microscopic evaluation is also becoming important in inspecting foreign particles that get mixed into manufactured materials. In the precision machinery field, it is becoming important to detect minute amounts of foreign particles contained in cleaning solutions when evaluating the cleanliness of parts.

[0003] Patent Document 1 discloses a technique for observing, under a microscope, particles suspended in a large amount of liquid at a low concentration. Patent Document 1 discloses a particle capture device and a particle measurement method, in which "a particle capture device for capturing particles contained in a liquid has a filtering means 10 including a filtering membrane 11. The filtering means 10 is configured so that the liquid flowing into the filtering means 10 passes through a part of the filtering membrane 11."

[0004] Japanese Patent Application Laid-Open No. 2017-138226

[0005] In the method described in Patent Document 1, a liquid containing fine particles may be passed through a portion of a filtration membrane to efficiently observe the fine particles on the filtration membrane. With the technique described in Patent Document 1, when recovering low-concentration fine particles to a density suitable for microscopic observation, a large amount of liquid must be passed through. If the area of ​​the filtration membrane through which the liquid passes is small, it takes a long time to filter a large amount of liquid, which is a problem.

[0006] The present invention has been made in view of the above background, and an object of the present invention is to realize efficient filtration.

[0007] In order to solve the above-mentioned problems, the present invention provides a filter comprising: a first liquid holding portion that holds a liquid to be filtered; a second liquid holding portion that has a first hole in a bottom surface of the first liquid holding portion and a second hole in a surface of the first liquid holding portion that is different from the bottom surface, the second liquid holding portion communicating with the first liquid holding portion via the first hole; and a third liquid holding portion that communicates with the first liquid holding portion via the second hole, wherein a first filter is provided in the first hole and a second filter is provided in the second hole. Other solutions will be described as appropriate in the embodiments.

[0008] According to the present invention, efficient filtration can be achieved.

[0009] FIG. 1 is a schematic diagram (1) showing an example of the configuration of a filtration device according to a first embodiment. FIG. 2 is a schematic diagram (2) showing an example of the configuration of a filtration device according to a first embodiment. FIG. 3 is a diagram showing an example of the configuration of a filtration system. FIG. 4 is a diagram showing an example of the configuration of a filtration device according to a third embodiment. FIG. 5 is a schematic diagram (1) showing the configuration of a first filter. FIG. 6 is a diagram (2) showing the configuration of a first filter. FIG. 7 is a diagram (1) showing an outline of filtration of a particulate suspension using a filtration device. FIG. 8 is a diagram (2) showing an outline of filtration of a particulate suspension using a filtration device. FIG. 9 is a diagram (3) showing an outline of filtration of a particulate suspension using a filtration device. FIG. 10 is a table showing numerical values ​​related to the area of ​​a first hole. FIG. 11 is a schematic diagram (1) showing an example of the configuration of a filtration device according to a second embodiment. FIG. 12 is a schematic diagram (2) showing an example of the configuration of a filtration device according to a second embodiment. FIG. 13 is a schematic diagram (3) showing an example of the configuration of a filtration device according to a second embodiment. FIG. 14 is a schematic diagram (4) showing an example of the configuration of a filtration device according to a second embodiment. FIG. 15 is a schematic diagram (1) showing an example of the configuration of a filtration device according to a third embodiment. FIG. 16 is a schematic diagram (2) showing an example of the configuration of a filtration device according to a third embodiment. FIG. 10 is a schematic diagram (part 3) showing an example of the configuration of a filtering device according to a third embodiment. FIG. 11 is a schematic diagram (part 4) showing an example of the configuration of a filtering device according to a third embodiment. FIG. 12 is a schematic diagram (part 1) showing an example of the configuration of a filtering device according to a fourth embodiment. FIG. 13 is a schematic diagram (part 2) showing an example of the configuration of a filtering device according to a fourth embodiment. FIG. 14 is a schematic diagram (part 3) showing an example of the configuration of a filtering device according to a fourth embodiment. FIG. 15 is a diagram showing a modified example of the arrangement of a first liquid holding portion. FIG. 16 is a diagram showing a filtering device according to a fifth embodiment. FIG. 17 is a diagram showing an example of the configuration of a filtering device according to a sixth embodiment. FIG. 18 is a flowchart showing the procedure of a filtering method according to the present embodiment. FIG. 19 is a schematic diagram (part 2) showing the procedure of a filtering method according to the present embodiment. FIG. 20 is a schematic diagram (part 3) showing the procedure of a filtering method according to the present embodiment. FIG. 21 is a schematic diagram (part 4) showing the procedure of a filtering method according to the present embodiment. FIG. 21 is a schematic diagram (part 5) showing the procedure of a filtering method according to the present embodiment.FIG. 1 is a schematic diagram (No. 7) for explaining the procedure of the filtration method according to the present embodiment. FIG. 2 is a schematic diagram (No. 8) for explaining the procedure of the filtration method according to the present embodiment. FIG. 3 is a schematic diagram (No. 9) for explaining the procedure of the filtration method according to the present embodiment. FIG. 4 is a schematic diagram (No. 10) for explaining the procedure of the filtration method according to the present embodiment. FIG. 5 is a schematic diagram showing another example of the filtration device according to the second embodiment. FIG. 6 is a diagram showing the configuration of another example of the first filter used in the filtration device according to the second embodiment. FIG. 7 is a schematic diagram showing another example of the filtration device according to the third embodiment.

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the term "microparticles 701 (see FIGS. 7 and 9)" hereinafter refers to particles formed by pulverization, sintering, crystallization, etc., particles precipitated or generated by chemical reactions, particles generated by external stimuli or factors, organic fibers, microplastics, pollen, cells, blood cells, bacteria, viruses, etc., but is not limited to these.

[0011] In addition, in each drawing, the same components are denoted by the same reference numerals, and repeated explanations will be omitted.

[0012] 1 and 2 are schematic diagrams showing an example of the configuration of a filtration device 1 according to a first embodiment. FIG. 1 shows a cross-sectional view taken along the line A2-A2 in FIG. 2, and FIG. 2 shows a cross-sectional view taken along the line A1-A1 in FIG. 1. As shown in FIG. 1, the filtration device 1 is composed of a first member 100, a second member 200, and a third member 300. The first member 100, which is a first container, has a first liquid holding portion 101 that is a cylindrical space inside and holds a liquid. In other words, the first liquid holding portion 101 is provided in the first member 100. A solution containing microparticles 701 (see FIGS. 7 and 9) (referred to as a microparticle suspension 700 (see FIGS. 7 and 9)) is injected into and held in the first liquid holding portion 101. 1 and 2, the cross-sectional shape (horizontal cross-sectional shape) of the first liquid holder 101 when cut in a direction perpendicular to the axial direction of the first liquid holder 101 is approximately circular. However, the transverse cross-sectional shape of the first liquid holder 101 is not limited to circular and may be polygonal. Furthermore, a first hole 411 is provided in the bottom surface of the first liquid holder 101, and a second hole 421 is provided in a surface (side surface) different from the bottom surface of the first liquid holder 101.

[0013] The second member 200 and the third member 300 are a second container that is separate from the first member 100 .

[0014] The second member 200 also includes a hollow second liquid holder 201. The second liquid holder 201 is capable of storing liquid therein. The liquid stored in the second liquid holder 201 is liquid that has passed through (been filtered by) a first filter 412. The second member 200 also has a hole in its upper surface. This hole, together with a hole in the bottom surface of the first liquid holder 101, forms a first hole 411. In other words, the second liquid holder 201 communicates with the first liquid holder 101 via the first hole 411. It is desirable that the hole in the bottom surface of the first liquid holder 101 and the hole in the top surface of the second member 200 have approximately the same size, but they may also be different sizes (in this embodiment, the hole sizes are approximately the same).

[0015] In this way, the second liquid holder 201 is provided in the second member 200 which is a container separate from the first member 100 .

[0016] The third member 300 has a third liquid holder 301, which is a hollow space inside. The third liquid holder 301 is capable of storing liquid. The liquid stored in the third liquid holder 301 is liquid that has passed through (been filtered by) a second filter 422. A hole is provided on the side surface of the third member 300. This hole, together with a hole provided on the side surface of the first liquid holder 101, forms a second hole 421. In other words, the third liquid holder 301 communicates with the first liquid holder 101 via the second hole 421. Note that it is desirable that the size of the hole provided on the side surface of the first liquid holder 101 and the size of the hole provided on the side surface of the third member 300 are approximately the same, but they may be different (the sizes of the holes are approximately the same in this embodiment).

[0017] In this embodiment, the relationship is: volume of the second liquid holder 201 > volume of the third liquid holder 301 > volume of the first liquid holder 101. However, the first liquid holder 101 only needs to have a volume that is large enough to hold the liquid before filtration. Similarly, the volume of the second liquid holder 201 only needs to be large enough to hold the liquid that has passed through (been filtered by) the first filter 412. And the volume of the third liquid holder 301 only needs to be large enough to hold the liquid that has passed through (been filtered by) the second filter 422.

[0018] A first exhaust port 501 is provided on one of the surfaces constituting the second liquid holder 201. The first exhaust port 501 is provided above the second liquid holder 201 to prevent the liquid stored in the second liquid holder 201 from flowing into the first exhaust port 501.

[0019] Additionally, a second exhaust port 502 is provided on one of the surfaces constituting the third liquid holder 301. To prevent the liquid stored in the third liquid holder 301 from flowing into the second exhaust port 502, the second exhaust port 502 is desirably provided above the third liquid holder 301.

[0020] A first filter 412 is provided in the first hole 411 , and a second filter 422 is provided in the second hole 421 .

[0021] As described above, the filtering device 1 has a first hole 411 provided in the bottom surface of the first liquid holding portion 101. The first hole 411 is provided with a first filter 412 for concentrating the microparticle suspension 700 and capturing the microparticles 701 (see FIGS. 7 and 9 ). The filtering device 1 also has a second hole 421 provided on a surface other than the bottom surface of the first liquid holding portion 101. The second hole 421 is provided with a second filter 422 for filtering the microparticle suspension 700. As described above, the second member 200 includes the second liquid holding portion 201. Similarly, the third member 300 includes the third liquid holding portion 301. The second liquid holding portion 201 and the third liquid holding portion 301 are substantially airtight.

[0022] The capacity of the first liquid holder 101 depends on the concentration of the microparticle suspension 700 to be filtered, the dyeing of the microparticles 701, and the conditions for the cleaning process of the microparticles 701. Specifically, the first liquid holder 101 has a capacity of approximately 10 to 2000 ml.

[0023] The first filter 412 and the second filter 422 are sheets with numerous fine holes and have a thickness of several μm to several tens of μm. The pore diameters of the first filter 412 and the second filter 422 are approximately 10 nm to 10 μm. However, the pore diameter is not limited to this, and any diameter may be used as long as it is smaller than the fine particles 701 suspended in the fine particle suspension 700 to be filtered and can recover the fine particles 701 as filtered material. It is preferable that the pore diameters of the numerous fine holes used in the first filter 412 and the second filter 422 are the same. However, the pore diameters of the first filter 412 and the second filter 422 do not necessarily have to be the same.

[0024] The area of ​​the second hole 421 is preferably larger than the area of ​​the first hole 411. In this embodiment, the area of ​​the second hole 421 is greater than the area of ​​the first hole 411. Because the first filter 412 is large enough to be installed in a microscope, the first hole 411 (first filter 412) cannot be made larger than the size required for installation in the microscope. Therefore, the filtration speed can be increased by making the area of ​​the second hole 421 (second filter 422) larger than that of the first hole 411 (first filter 412). With this configuration, it is possible to shorten the filtration time compared to when only the first hole 411 (first filter 412) is provided.

[0025] However, the second hole 421 does not necessarily have to be larger than the first hole 411. The second liquid holder 201 and the third liquid holder 301 each have a capacity large enough to store the waste liquid 711 (see FIG. 9 ), which is the liquid generated in one filtration process. The first member 100, the second member 200, and the third member 300 are made of a material that is resistant to the solution used in the microparticle suspension 700. Examples of such materials include polypropylene (PP), polycarbonate (PC), polyethylene (PE), polyethersulfone (PES), polyethylene terephthalate (PET), fluorine-based resins such as polytetrafluoroethylene, nylon, and polyetheretherketone (PEEK). Using these resin materials offers the advantage of being inexpensive and lightweight.

[0026] 1, the bottom surface (bottom) of the first liquid holding portion 101 and the lower end of the second hole 421 are configured to have a predetermined distance between them. As a result, a measuring portion 113 capable of storing a predetermined amount of microparticle suspension 700 is formed below the second hole 421. However, the measuring portion 113 does not necessarily have to be provided. If the measuring portion 113 is not provided, the distance from the lower end of the second hole 421 to the first filter 412 will be approximately zero.

[0027] The predetermined distance is the height direction distance between the bottom surface of the first liquid holding portion 101 (i.e., the upper surface of the first filter 412) and the lower end of the second hole 421, and this predetermined distance is set appropriately depending on the specifications of the filtration device 1. If this predetermined distance is shortened, the volume of the measuring portion 113 will be smaller, and if it is longer, the volume will be larger.

[0028] The outer shape of the first member 100 in the portion of the first liquid holder 101 is not limited to the rectangular shape shown in FIG. 1, but may be circular.

[0029] (Filtration System Z) FIG. 3 is a diagram showing an example of the configuration of the filtration system Z. In FIG. 3, the filtration device 1 is shown as a cross-sectional view taken along the arrows A2-A2 in FIG. 2. When the filtration system Z is in use, an exhaust pump 521 is connected to the first exhaust port 501 and the second exhaust port 502 of the filtration device 1. The exhaust pump 521 generates a pressure difference used for filtering the liquid. The first exhaust port 501 and the second exhaust port 502 are connected to the exhaust pump 521 via a pipe 513. The pipe 513 is provided with a first exhaust valve 511, a second exhaust valve 512, and a pipe filter 531. The pipe filter 531 prevents fine particles from flowing from the filtration device 1 into the exhaust pump 521.

[0030] In this manner, the second liquid holder 201 and the third liquid holder 301 are connected to the exhaust pump 521 .

[0031] The first exhaust valve 511 is provided in the first exhaust port 501 and is capable of switching between an exhaust state and an open-to-atmosphere state of the second liquid holder 201. The second exhaust valve 512 is provided in the second exhaust port 502 and, like the first exhaust valve 511, is capable of switching between an exhaust state and an open-to-atmosphere state of the third liquid holder 301. In this way, the first exhaust valve 511 and the second exhaust valve 512 are switchable between the exhaust pump 521 side and the open-to-atmosphere side.

[0032] The exhaust pump 521 is a pump capable of operating at a low vacuum, such as a diaphragm vacuum pump or a dry pump. As described above, the piping filter 531 is used to prevent fine particles from being sucked into the exhaust pump 521 and to prevent the exhaust pump 521 from malfunctioning or the fine particles from being released from the exhaust port of the exhaust pump 521. The piping filter 531 is, for example, an air filter such as a HEPA filter. In addition to the piping filter 531, a trap tube (not shown) or the like may be used as needed to prevent fine particles from being sucked into the exhaust pump 521. Note that, although one piping filter 531 is provided in the example shown in FIG. 3 , two piping filters may be provided corresponding to the first exhaust valve 511 and the second exhaust valve 512, respectively.

[0033] The first exhaust valve 511 and the second exhaust valve 512 can be either manual or electrically operated. When electrically operated first exhaust valves 511 and 512 are used, operation can be simplified by linking the operation of the exhaust pump 521 with the control device 600. The piping 513 is made of, for example, metal or rubber. It is preferable that the piping 513 be hard enough to prevent the piping 513 from being crushed by suction during exhaust and preventing the exhaust from being obstructed. If the first exhaust valve 511 and the second exhaust valve 512 are electrically operated, the first exhaust valve 511 and the second exhaust valve 512 can be controlled by the control device 600. The exhaust pump 521 may be controlled manually or by the control device 600. The waste liquid 711 (see FIG. 9 ) collected in the second liquid holder 201 or the third liquid holder 301 after filtration can be treated, as necessary, using a purification (sterilization) device (not shown).

[0034] (Replacing the First Filter 412) FIG. 4 is a diagram showing the disassembly of the filtration device 1. In FIG. 4, the filtration device 1 is shown in a cross-sectional view taken along the arrows similar to FIG. 1. As shown in FIG. 4, the first member 100 is detachable from the second member 200 and the third member 300. By removing the first member 100 from the second member 200 and the third member 300, the first filter 412 provided in the first hole 411 becomes detachable. In this manner, the user can easily remove the first filter 412. After the microparticle suspension 700 is filtered by the first filter 412 and the second filter 422, the user can remove the first filter 412. Then, by placing the removed first filter 412 on a microscope (not shown), the user can observe the microparticles 701 collected by the first filter 412 using the microscope. The microscope in this embodiment refers to an electron microscope, an optical microscope, an atomic force microscope, or the like. The particle suspension 700 is suction-filtered by the exhaust pump 521 through the first filter 412, which has a large number of micropores, resulting in particles 701 being dispersed and captured on the first filter 412. The first filter 412 on which the particles 701 are dispersed and captured serves as a sample for microscopic observation. In this manner, a sample for microscopic observation can be prepared. The second filter 422 is not used for microscopic observation.

[0035] Furthermore, the second member 200 and the third member 300 may be disassembled or may not be disassembled.

[0036] (Configuration of First Filter 412) FIGS. 5 and 6 are diagrams showing the configuration of the first filter 412. As shown in FIGS. 5 and 6, the first filter 412 has a filter body 431 and a frame 432 provided around the outer periphery of the filter body 431. The frame 432 has a hardness that allows it to be gripped. In the example shown in the supplementary figure, a frame 432a is provided around a rectangular filter body 431a. In addition, in the example shown in FIG. 6, a frame 432b is provided around a circular filter body 431b. Note that the shapes of the filter body 431 and the frame 432 are not limited to those shown in FIGS. 5 and 6, and may be elliptical or polygonal shapes other than rectangular.

[0037] As shown in FIGS. 5 and 6 , the filter body 431, which is thin and difficult to handle alone, is fixed to the frame 432. This configuration makes it easier for the user to grasp the first filter 412. As a result, it becomes easier to attach and detach the first filter 412 to and from the filtering device 1, and to mount the first filter 412 on a sample stage of a microscope (not shown). By using a conductive material for the frame 432, it is possible to reduce charging caused by an electron beam, for example, during electron microscope observation. Alternatively, the filter body 431 may be directly subjected to a conductive treatment, such as a coating of gold or platinum. This is also effective in reducing charging caused by the electron beam.

[0038] The filter body 431 is made of, for example, polycarbonate (PC), polyester (PET), polyimide (PI), regenerated cellulose, nitrocellulose, cellulose acetate, cellulose mixed ester, polypropylene, nylon, polyamide, polytetrafluoroethylene (PTFE), polyvinylidene chloride (PVC), polyvinylidene fluoride (PVDF), polyethersulfone (PES), etc.

[0039] A membrane filter suitable for the filter body 431 is selected from the following points of view: (1) Chemical resistance to the reagent used, (2) Ability of the filter material to adsorb components contained in the sample, and (3) Whether the pore size of the filter body 431 is small compared to the particulates 701 to be collected.

[0040] Furthermore, the filter body 431 of the first filter 412 and the filter body of the second filter 422 may be made of the same material or different materials.

[0041] (Outline of Filtration) Next, an outline of the filtration of the particulate suspension 700 (liquid) using the filtration device 1 will be described with reference to Figs. 7 to 9. The detailed procedure for filtering the particulate suspension 700 will be described later. Also, Fig. 3 will be referenced as appropriate. Figs. 7 to 9 are diagrams showing an outline of the filtration of the particulate suspension 700 using the filtration device 1. Furthermore, in the following figures, only elements of the filtration device 1 that are necessary for the explanation will be labeled.

[0042] 7 , a microparticle suspension 700 containing microparticles 701 is injected into the first liquid holder 101. The injected microparticle suspension 700 is substantially prevented from flowing into the second liquid holder 201 and the third liquid holder 301 by the first filter 412 and the second filter 422.

[0043] Although not shown in FIGS. 7 to 9 , an exhaust pump 521 is connected to the first exhaust port 501 and the second exhaust port 502 as shown in FIG. 3 . The first exhaust valve 511 and the second exhaust valve 512 are switched to the connection side (exhaust state) with the exhaust pump 521. Then, suction is performed by the exhaust pump 521, thereby sucking (exhausting) the second liquid holding portion 201 and the third liquid holding portion 301. As a result, a solution (wastewater 711) in which the microparticles 701 have been filtered from the microparticle suspension 700 flows into the second liquid holding portion 201 and the third liquid holding portion 301 via the first filter 412 and the second filter 422. At this time, the microparticles 701 are filtered by the first filter 412 and the second filter 422.

[0044] As a result, as shown in Fig. 8, the waste liquid 711 is collected in the second liquid holding portion 201 and the third liquid holding portion 301. Then, as shown in Fig. 8, as a result of suction by the exhaust pump 521, the microparticle suspension 700 injected into the first liquid holding portion 101 is concentrated up to the vicinity of the measuring portion 113 provided below the second filter 422. Concentrated up to the vicinity of the measuring portion 113 means that the liquid level of the microparticle suspension 700 reaches near the upper end of the measuring portion 113 (the lower end of the second hole 421).

[0045] 8, when the microparticle suspension 700 is concentrated to the vicinity of the measuring unit 113, the first exhaust valve 511 connected to the second liquid holding unit 201 is opened to the atmosphere. The second exhaust valve 512 remains switched to the side connected to the exhaust pump 521 (exhaust state). As a result, suction filtration by the first filter 412 is stopped, and suction filtration by only the second filter 422 continues. In other words, filtration is performed only by the second filter 422 (third liquid holding unit 301).

[0046] 8 , when the second liquid holder 201 is sucked, there is a risk that the liquid level of the microparticle suspension 700 will be sucked to a position below the upper end of the measuring section 113. In contrast, when only the third liquid holder 301 is sucked and the liquid level of the microparticle suspension 700 reaches the upper end of the measuring section 113, no more solution of the microparticle suspension 700 will be discharged into the third liquid holder 301.

[0047] Then, as shown in FIG. 9 , when the microparticle suspension 700 is concentrated to below the second filter 422, suction by the exhaust pump 521 is stopped. This also stops filtration by the second filter 422, and the concentrated microparticle suspension 700 is stored in the measuring section 113 below the second filter 422. The microparticle suspension 700 stored in the measuring section 113 is appropriately referred to as a concentrated liquid. By adjusting the first exhaust valve 511 using the method shown in FIGS. 7 to 9 , the microparticle suspension 700 can be concentrated to a certain amount. After this, a reagent or the like is added to the concentrated liquid, and then the second liquid holding section 201 is sucked, and the concentrated liquid stored in the measuring section 113 is recovered in the second liquid holding section 201. Thereafter, the first filter 412 is recovered. This process will be described later.

[0048] (Area of ​​First Hole 411) Fig. 10 is a table showing recommended values ​​for the area of ​​the first hole 411. The area of ​​the first hole 411 for collecting the microparticles 701 is determined by the number of microparticles 701 in the microparticle suspension 700, the observation area per field of view when observing with a microscope, and the particle density per observation area, as shown in Fig. 10. The observation area per field of view with a microscope is determined by the observation magnification of the microscope.

[0049] For example, using a filtering device 1 with a diameter of the first holes 411 of φ2.5 mm, 50 mL of the microparticle suspension 700 with a concentration of microparticles 701 of 2000 particles / mL is filtered by suction, and the observation field of view is 0.001 mm. ２ In this case, 20 particles 701 can be observed per field of view. When observed with a microscope at a magnification of 100 to 10,000 times, the area per field of view of the observed image is 0.0001 to 0.01 mm. ２The particles 701 are concentrated and collected at a density that allows one or more particles 701 to be observed in one field of view, so that the particles 701 can be observed in any field of view. In other words, the concentration of the particles 701 and the diameter of the first hole 411 (first filter 412) are adjusted to a density that allows one or more particles 701 to be observed in one field of view. In this way, the particles 701 can be observed in any field of view, and the observation time can be shortened.

[0050] It should be noted that when the diameter of the first holes 411 is large, air bubbles may form in a portion of the first filter 412. When air bubbles form in the first filter 412 in this way, a state occurs in which the fine particles 701 are not collected. In such a case, uniformity in the dispersion of the fine particles 701 in the first filter 412 cannot be maintained. Furthermore, if the diameter of the first holes 411 is small and air bubbles cover the entire bottom surface, suction filtration may not be possible, and the particles may not be collected. Although it depends on conditions such as the concentration and amount of liquid, it is desirable that the diameter of the first holes 411 be approximately 0.5 to 6 mm.

[0051] The filtration device 1 of the first embodiment has a first filter 412 installed in the first hole 411 and a second filter 422 installed in the second hole 421. Thus, filtration using multiple filters can shorten the filtration time. Furthermore, the area of ​​the second hole 421 (i.e., the area of ​​the second filter 422) is larger than the area of ​​the first hole 411 (first filter 412). This configuration can further shorten the filtration time. Furthermore, the filtration device 1 of the first embodiment can efficiently concentrate a large amount of low-concentration microparticle suspension and further collect the microparticles in an area suitable for observation.

[0052] Furthermore, by providing the measuring unit 113, it is possible to maintain a constant amount of liquid during the process of concentrating the solution (particle suspension 700). Furthermore, by adding an additive to the solution (particle suspension 700) maintained in the measuring unit 113, a process of reacting the particles 701 with the additive at a desired (predetermined) concentration can be performed in the measuring unit 113. Furthermore, by filtering the particles 701 with the first filter 412 having a small filtration area, it is possible to collect the particles 701 at a density suitable for microscopic observation, facilitating microscopic observation.

[0053] Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS. 11 to 14. In the second embodiment, additional components are added to the filtration device 1 of the first embodiment. Hereinafter, descriptions of parts common to the first embodiment may be omitted. FIGS. 11 to 14 are schematic diagrams showing an example of the configuration of a filtration device 1a according to the second embodiment. FIGS. 11 to 14 show an example of the configuration of a multi-well filtration device 1a having a plurality of first holes 411. FIG. 11 is a diagram showing a longitudinal cross section of the filtration device 1a (cross section B4-B4 in FIG. 12). FIG. 12 is a cross section taken along the arrows B1-B1 in FIG. 11. And FIG. 13 is a cross section taken along the arrows B2-B2 in FIG. 11. Furthermore, FIG. 14 is a cross section taken along the arrows B3-B3 in FIG. 11.

[0054] The first member 100a in the filtering device 1a has a configuration in which the first holes 411 are arranged in two parallel rows. A first filter 412 is provided in each of the first holes 411. In the example shown in FIGS. 11 to 13, four first holes 411 are provided per row of the first holes 411. Note that, hereinafter, the row of the first holes 411 may be simply referred to as a row. In this way, the filtering device 1a has a plurality of first holes 411, and a first filter 412 is provided for each of the first holes 411.

[0055] Also, second holes 421 and second filters 422 are provided to correspond to each row of the first holes 411. Furthermore, third liquid holders 301 are provided to correspond to each row of the first holes 411. In other words, one second hole 421, one second filter 422, and one third liquid holder 301 are provided for one row of the first holes 411.

[0056] 12, the first holes 411 are arranged in a row at equal intervals. However, the first holes 411 do not necessarily have to be arranged at equal intervals. The number of first holes 411 is determined by the movable range of the microscope stage, the intervals between the first holes 411, etc.

[0057] 13 , in the filtration device 1a, a first liquid holding portion 101 is provided for each row. That is, a common first liquid holding portion 101 is provided for the first holes 411 that make up the row. In this way, in the filtration device 1a, a common first liquid holding portion 101, second holes 421, and second filters 422 are provided for the multiple first holes 411.

[0058] In addition to the effects shown in the first embodiment, the filtering device 1a having such a configuration is suitable for filtering one type of microparticle suspension 700 using each of the first filters 412 arranged in one row. In other words, one type of microparticle suspension 700 can be filtered through one row of the first holes 411. However, as shown in FIG. 13 , the measuring sections 113 are formed to correspond to each of the first holes 411. In other words, the first liquid holding sections 101 are connected above the measuring sections 113. Then, different reagents 731 (see FIG. 35 ) can be added to the microparticles 701 filtered through each of the first filters 412.

[0059] Each of the first holes 411 in one row can have the same area (the same diameter). In this case, an equal amount of microparticles 701 from the microparticle suspension 700 can be filtered and collected in each of the first filters 412 constituting one row. The same microparticle suspension 700 may be poured into each of the first liquid holders 101 arranged in parallel, or microparticle suspensions 700 containing different microparticles 701 may be poured into each of the first liquid holders 101. As shown in FIG. 11 , the second hole 421 is located above the measuring unit 113. As shown in FIGS. 12 to 14 , the second hole 421 and second filter 422 connected to the first liquid holder 101 are provided corresponding to each first liquid holder 101. That is, one second hole 421 and one second filter 422 are provided for each first liquid holder 101. That is, as described above, one second hole 421 , one second filter 422 and one third liquid holder 301 are provided for one row of the first holes 411 .

[0060] Incidentally, in the filtering device 1a as well, the first member 100a is detachable from the second member 200 and the third member 300. In addition, a common second liquid holding portion 201 and a common third liquid holding portion 301 are provided for each first liquid holding portion 101. The total area of ​​the first filter 412 is less than the area of ​​the second filter 422.

[0061] 11, the first member 100a of the filtering device 1a is divided into members 131, 132a, and 132b. In this configuration, the user can individually remove the members 132a and 132b from the second member 200 and the third member 300. However, the first member 100a does not have to be divided as shown in FIG. 11.

[0062] Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIGS. 15 to 18 . FIGS. 15 to 18 are schematic diagrams illustrating an example of the configuration of a filtration device 1b according to the third embodiment. FIGS. 15 to 18 illustrate an example of the configuration of a multi-well filtration device 1b having a plurality of first holes 411. FIG. 15 is a schematic diagram illustrating an example of the configuration of a filtration device 1b according to the third embodiment. FIG. 15 is a longitudinal cross-sectional view of the filtration device 1b, and FIG. 16 is a cross-sectional view taken along the arrows C1-C1 in FIG. 15 . FIG. 17 is a cross-sectional view taken along the arrows C2-C2 in FIG. 15 . As shown in FIGS. 15 and 16 , the filtration device 1b has one row of first holes 411 formed in the first member 100b. However, as shown in FIG. 11 , two rows of first holes 411 may be arranged in parallel. A plurality of first holes 411 (four in the example shown in FIG. 16 ) are formed in one row. In this manner, the filtering device 1 b is provided with a plurality of first holes 411 , and a first filter 412 is provided for each of the first holes 411 .

[0063] As shown in FIG. 16 , a first liquid holder 101 is provided for each of the multiple first holes 411. That is, a first liquid holder 101 is independently provided for each of the first holes 411 arranged in a row. Also, as shown in FIG. 16 , a measuring unit 113 is provided for each of the first liquid holders 101. With this configuration, different types of microparticle suspensions 700 can be injected into each of the first liquid holders 101. That is, one or more types (plural) of microparticle suspensions 700 can be injected into the filtration device 1b. This allows different microparticle suspensions 700 to be filtered in each of the first filters 412. Also, as shown in FIG. 15 , the lower end of the second hole 421 is located at least above the measuring unit 113. Also, as shown in FIG. 17 , the second filter 422 connected to the first liquid holder 101 can be configured as a single filter.

[0064] It should be noted that a second liquid holding portion 201 and a third liquid holding portion 301 are provided in common for each first liquid holding portion 101 .

[0065] Fig. 18 is a diagram showing another example of the filtering device 1b. As shown in Fig. 18, the second filters 422 connected to the first liquid holders 101 may be provided so as to correspond to each of the multiple first liquid holders 101.

[0066] In the filtering device 1b, the total area of ​​the first filters 412 is less than the total area of ​​the second filters 422. However, the total area of ​​the first filters 412 may be equal to or greater than the total area of ​​the second filters 422.

[0067] Fourth Embodiment Next, a fourth embodiment of the present invention will be described with reference to FIGS. 19 to 22. FIGS. 19 and 20 are schematic diagrams illustrating an example of the configuration of a filtration device 1c according to the fourth embodiment. FIGS. 19 and 20 are schematic diagrams illustrating an example of the configuration of a multi-well filtration device 1c having a plurality of first holes 411. FIG. 19 shows a longitudinal cross-sectional view of the filtration device 1c (a cross-sectional view taken along arrows D2-D2 in FIG. 20), and FIG. 20 shows a transverse cross-sectional view of the filtration device 1c (a cross-sectional view taken along arrows D1-D1 in FIG. 19). Note that the drainage pipe 551 and the waste liquid recovery unit 552 are omitted from FIG. 20. As shown in FIGS. 19 and 20, the filtration device 1c is composed of a fourth member 150, which is a first container, and a second member 200. The fourth member 150 corresponds to the first member 100a and the third member 300 shown in FIGS. 11 to 18.

[0068] In the filtering device 1c, a housing 122 of the fourth member 150 has a plurality of recesses formed therein, thereby forming a plurality of first liquid holders 101 (four in the example shown in FIGS. 19 and 20). A plurality of first holes 411 (four in the example shown in FIGS. 19 and 20) are also provided, and a first filter 412 is provided in each of the first holes 411. In the filtering device 1c, the second holes 421 are provided in the fourth member 150 (first container) along with the first liquid holders 101. Furthermore, a first liquid holder 101 is provided for each of the plurality of first holes 411. As shown in FIG. 20, a space 121 corresponding to the third liquid holder 301 is provided between the first liquid holder 101 and the housing 122.

[0069] A second filter 422 is provided on a portion of the wall surface constituting the first liquid holder 101. The second filter 422 is provided in a second hole 421 provided in the side surface of the first liquid holder 101. In this manner, a space 121 is provided between the periphery of the second hole 421 and the housing 122 of the fourth member 150, which is the first container. In the example shown in FIG. 20 , the cylindrical second filter 422 is provided so as to surround the first liquid holder 101, but this is not limiting. As shown in FIG. 21 , the second filter 422 may be provided only on a portion of the periphery of the first liquid holder 101. In this case, the first liquid holder 101 is configured with the housing 122 except for the portion where the second filter 422 is provided. The measuring section 113 extends from the lower end of the second hole 421 to the bottom surface (bottom) of the first liquid holder 101.

[0070] The housing 122 is provided with a second exhaust port 502. The space 121 is connected to a waste liquid collection unit 552 via the second exhaust port 502 and a drainage pipe 551. An exhaust pump 521 (see FIG. 3) is connected to a suction connection part 553 connected to the top of the waste liquid collection unit 552. After a microparticle suspension 700 (see FIG. 7, etc.) is injected into the first liquid holder 101, suction is performed by the exhaust pump 521 connected to the suction connection part 553. This generates a pressure difference between the space 121 connected to the waste liquid collection unit 552 and the first liquid holder 101. This pressure difference causes waste liquid 711 (see FIGS. 8 and 9) to be discharged outside the first liquid holder 101 via the second filter 422. The discharged waste liquid 711 is collected in the waste liquid collection unit 552 through the drainage pipe 551.

[0071] Furthermore, the top of the first liquid holder 101 is joined to the top of the housing 122. Therefore, the space 121 is sealed except for the second exhaust port 502.

[0072] Note that not all first liquid holders 101 need to have the configuration shown in Fig. 20 or 21. For example, a common first liquid holder 101 may be provided for multiple first filters 412 (the first liquid holders 101 shown in Figs. 19 and 20 may be connected).

[0073] 19 and 20 , in the filtering device 1c, a portion of the side surface (wall surface) constituting the first liquid holding portion 101 is configured with a second filter 422. In the filtering device 1c, the housing 122 ensures the airtightness of the space 121 outside the first liquid holding portion 101. The space 121 is suctioned by the exhaust pump 521 connected to the second exhaust port 502, whereby the microparticle suspension 700 is filtered by the second filter 422 provided around the first liquid holding portion 101.

[0074] Furthermore, the bottom surface of each first liquid holder 101 forms a first hole 411. As shown in Figures 20 and 21, the first liquid holders 101 are arranged at equal intervals. However, the first liquid holders 101 do not necessarily have to be arranged at equal intervals. Furthermore, as described above, the housing 122 forms a single, highly airtight space 121 on the outside of the first liquid holders 101.

[0075] Fig. 22 is a diagram showing a modified example of the arrangement of the first liquid holding units 101. In the example shown in Fig. 22, the first liquid holding units 101 are arranged at equal intervals in the row and column directions. The periphery of the evenly spaced first liquid holding units 101 is covered with a housing 122 as shown in Fig. 20 or 21, and the space between the housing 122 and each first liquid holding unit 101 is substantially sealed. Note that, in Fig. 22 as well, the second filter 422 is provided in the second hole 421.

[0076] In the configuration of the filtration device 1c, the space 121 provided around the first liquid holder 101 corresponds to the third liquid holder 301, and there is no need to provide the third liquid holder 301 as in the first to third embodiments. Therefore, as shown in Figure 22, the first holes 411 (i.e., cylindrical containers) can theoretically be arranged without any restrictions. The number of first holes 411 is determined by the movable range of the microscope stage and the spacing between the first holes 411.

[0077] Fifth Embodiment Next, a fifth embodiment of the present invention will be described with reference to Fig. 23 and Fig. 24. Fig. 23 and Fig. 24 are diagrams showing a filtering device 1 according to the fifth embodiment. The filtering device 1 according to the fifth embodiment has a liquid delivery nozzle 801 that can inject a liquid into a first liquid holding portion 101. The liquid delivered by the liquid delivery nozzle 801 is a microparticle suspension 700 or the like. Fig. 23 shows the filtering device 1 according to the first embodiment equipped with the liquid delivery nozzle 801, and Fig. 24 shows the filtering device 1b according to the third embodiment equipped with the liquid delivery nozzle 801.

[0078] 23 and 24 , when the microparticle suspension 700 is delivered to the first liquid holder 101, the liquid can be discharged from a predetermined position (predetermined height) relative to the first filter 412 at a predetermined speed. The predetermined position (predetermined height) is a height at which no air bubbles are generated on the surface of the first filter 412. When the diameter of the first hole 411 is small, if the microparticle suspension 700 is delivered from a high position relative to the first filter 412, air bubbles may cover the entire bottom surface. In such a case, suction filtration may not be performed, and the microparticles 701 may not be collected. Note that it is also possible to increase the suction force of the exhaust pump 521 to suck the air bubbles toward the second liquid holder 201. However, suction of the air bubbles by the exhaust pump 521 is not preferable because strong suction of the microparticle suspension 700 is undesirable and makes it difficult to store the microparticle suspension in the measuring unit 113.

[0079] 23 and 24 , the liquid supply nozzle 801 is positioned near the first filter 412, and then the microparticle suspension 700 is supplied from the liquid supply nozzle 801. This allows the microparticle suspension 700 supplied from the liquid supply nozzle 801 to dissipate air near the first filter 412. As a result, it is possible to prevent air bubbles from being generated on the first filter 412.

[0080] 23 and 24 , even when the microparticle suspension 700 is delivered, air bubbles may cover the entire bottom surface of the first hole 411, i.e., the entire upper surface of the first filter 412. This condition may also prevent the exhaust pump 521 from suctioning and filtering the microparticle suspension 700. In such a case, the delivery nozzle 801 is moved closer to the first filter 412 than when the microparticle suspension 700 is delivered, and the microparticle suspension 700 is suctioned and discharged at a predetermined speed one or more times. In this way, the delivery nozzle 801 can suck in, eliminate, or release the air bubbles into the microparticle suspension 700. This allows the air bubbles to be removed from the bottom surface of the first hole 411 (i.e., the upper surface of the first filter 412).

[0081] In this manner, when the first hole 411 is not filled with the microparticle suspension 700, the liquid delivery nozzle 801 is installed at a predetermined position on the first filter 412. As described above, when the first hole 411 is not filled with the microparticle suspension 700, this occurs when air bubbles are present in the first hole 411 (the upper surface of the first filter 412). The "predetermined position" refers to a position suitable for removing air bubbles. The microparticle suspension 700 is then discharged from the liquid delivery nozzle 801 at a predetermined speed. The "predetermined speed" refers to a speed suitable for removing air bubbles. Air bubbles may remain in the first hole 411 even after the microparticle suspension 700 is injected into the first liquid holding portion 101. In such a case, as described above, the liquid delivery nozzle 801 is installed near the first filter 412, and then the air bubbles can be removed by repeatedly suctioning and delivering the liquid using the liquid delivery nozzle 801. If the first holes 411 (that is, the upper surface of the first filter 412) are filled with the microparticle suspension 700, this process does not need to be performed.

[0082] 24 , in the case of a multi-well filtration device 1b in which each of the first liquid holding portions 101 is independent, it is possible to install a liquid delivery nozzle 801 in each of the first liquid holding portions 101. In this way, when delivering liquid to the first liquid holding portion 101, it is possible to deliver liquid to each of the first holes 411 one by one, or to deliver liquid to multiple first holes 411 simultaneously using multiple liquid delivery nozzles 801.

[0083] On the other hand, as shown in FIGS. 11 to 14 , there may also be cases where the first liquid holder 101 is not independent of the first holes 411. That is, the first liquid holder 101 may be provided in common with a plurality of first holes 411. In such cases, when injecting the liquid into the first liquid holder 101, it is preferable to simultaneously deliver the liquid to each of the first holes 411 using a plurality of liquid delivery nozzles 801. By simultaneously delivering the liquid using a plurality of liquid delivery nozzles 801, it is possible to prevent air bubbles from transferring to adjacent first holes 411 (i.e., the first filters 412). In such cases, it is preferable to simultaneously dispense the microparticle suspension 700 into the plurality of first holes 411 using a dispenser (not shown) having a plurality of pipettes (multi-pipettes) corresponding to the liquid delivery nozzles 801. In particular, by adjusting the spacing between the first holes 411 to that of a commercially available multi-pipette, it becomes possible to simultaneously deliver liquid to a plurality of first holes 411. Alternatively, the spacing between the first holes 411 may be set to match the spacing of an arbitrarily designed multi-pipette.

[0084] The placement of the liquid supply nozzle 801 in the first liquid holding portion 101 and the supply of the microparticle suspension 700 by the liquid supply nozzle 801 may be performed manually or by machine.

[0085] Sixth Embodiment Next, a sixth embodiment of the present invention will be described with reference to FIG. 25 . FIG. 25 is a diagram illustrating an example of the configuration of a filtering device 1 according to the sixth embodiment. The filtering device 1 illustrated in FIG. 25 is the filtering device 1 illustrated in FIG. 1 , and includes a liquid delivery nozzle 801 capable of injecting a liquid into the first liquid holder 101. The liquid may be the microparticle suspension 700 or a cleaning liquid. After the microparticle suspension 700 is filtered according to the procedures illustrated in FIGS. 7 and 9 , microparticles 701 may be captured by the second filter 422. In such a case, a predetermined liquid is delivered from the liquid delivery nozzle 801 toward the second filter 422. The predetermined liquid may be the microparticle suspension 700 or a cleaning liquid. In this manner, the microparticles 701 captured by the second filter 422 are cleaned. This allows the microparticles 701 captured by the second filter 422 to be returned to the microparticle suspension 700 injected into the first liquid holder 101. At this time, it is desirable that at least the first hole 411 be filled with liquid.

[0086] 25 is applicable not only to the filtering device 1 shown in the first embodiment, but also to the filtering devices 1a to 1c shown in the second to fifth embodiments. In the case where the first liquid holding portion 101 is not independent of the first hole 411, as in the filtering device 1a shown in the second embodiment (FIGS. 11 to 14), it is preferable to feed the suspension while the liquid level is above the measuring portion 113. If the liquid feeding nozzle 801 cleans the second filter 422 while the liquid level of the microparticle suspension 700 is below the lower end of the second filter 422, there is a possibility that the microparticles 701 may flow into a specific measuring portion 113. This is because there is a possibility that the concentration of the microparticle suspension 700 stored in each measuring portion 113 may differ.

[0087] The method described in the sixth embodiment can also be applied to the filtration device 1b shown in the third embodiment (FIGS. 15 to 18) and the filtration device 1c shown in the fourth embodiment (FIGS. 19 to 22). In the filtration devices 1b and 1c, the first liquid holding portions 101 are provided independently of each other with respect to the first holes 411. When the second filter 422 of such filtration devices 1b and 1c is cleaned by the method described in the sixth embodiment, it is sufficient that at least the first holes 411 are filled with liquid. This is because, unlike the filtration device 1a shown in the second embodiment, there is no possibility of differences in the concentrations of the microparticle suspensions 700 stored in the respective measuring portions 113.

[0088] [Seventh Embodiment: Filtration Method] Next, referring to the flowchart of FIG. 26 and also to FIGS. 27 to 36, steps for filtering a microparticle suspension 700 using a filtration device 1 will be described. FIG. 26 is a flowchart illustrating the steps of the filtration method according to this embodiment. FIGS. 27 to 36 are schematic diagrams for explaining the steps of the filtration method according to this embodiment. While FIGS. 27 to 36 use the filtration device 1 shown in the first embodiment, the filtration devices 1a to 1c according to the second to fourth embodiments can also concentrate and recover the microparticle suspension 700 using similar steps. In the following description, step numbers refer to the step numbers in the flowchart shown in FIG. 26. As shown in FIG. 3, the filtration device 1 is connected to an exhaust pump 521. In the description of FIGS. 27 to 36, FIG. 3 will be referred to as appropriate. In FIGS. 26 to 36, the first exhaust valve 511, the second exhaust valve 512, and the exhaust pump 521 are controlled by the control device 600.

[0089] First, as shown in FIG. 27 , the microparticle suspension 700 is injected into the first liquid holder 101 (S1). At this time, it is desirable that the liquid feed nozzle 801 feeds the liquid from a predetermined position to the first filter 412 at a predetermined liquid feed rate, as shown in FIGS. 23 and 24 . The predetermined position and predetermined liquid feed rate are those of the liquid feed nozzle 801 that do not generate air bubbles on the surface of the first filter 412. That is, when the liquid microparticle suspension 700 is injected into the first liquid holder 101 from the liquid feed nozzle 801, the injection is performed in the following procedure. That is, the microparticle suspension 700 is injected from the liquid feed nozzle 801 into the first filter 412 from a height that does not generate air bubbles on the surface of the first filter 412. This avoids the problem that, due to the small diameter of the first hole 411, air bubbles cover the entire surface of the first filter 412, making suction filtration and recovery of the microparticles 701 impossible.

[0090] Next, as shown in Fig. 28 , concentration by suction filtration via the first filter 412 and the second filter 422 is started (S2). Specifically, the control device 600 switches the first exhaust valve 511 and the second exhaust valve 512 shown in Fig. 3 so that they are connected to the exhaust pump 521 (see Fig. 3 ). Then, the control device 600 causes the exhaust pump 521 to exhaust air, thereby exhausting the second liquid holder 201 and the third liquid holder 301 (white arrows in Fig. 28 ).

[0091] Step S2 is the first process. That is, in step S2, when the microparticle suspension 700 containing microparticles 701 is injected into the first liquid holder 101, the exhaust pump 521 evacuates the second liquid holder 201 and the third liquid holder 301.

[0092] As a result, suction filtration of the microparticle suspension 700 is performed by the first filter 412 and the second filter 422. By this suction filtration, the waste liquid 711 is discharged to the second liquid holder 201 and the third liquid holder 301. Note that if air bubbles are present on the bottom surface of the first hole 411 (i.e., on the surface of the first filter 412), the suction filtration by the first filter 412 may be hindered. In such a case, as shown in FIGS. 23 and 24 , suction and discharge are repeated one or more times with the tip of the liquid delivery nozzle 801 brought close to the first filter 412. In this manner, air bubbles can be removed from the bottom surface of the first hole 411 (on the surface of the first filter 412).

[0093] 29 , when the liquid level of the microparticle suspension 700 reaches the vicinity of the measuring unit 113 (near the lower end of the second hole 421), the control device 600 stops suction of the second liquid holder 201 (S3). The control device 600 then switches the first exhaust valve 511 to the atmosphere-opening side. This opens the second liquid holder 201 to the atmosphere. After the second liquid holder 201 is opened to the atmosphere, only the third liquid holder 301 is evacuated (shown by the hollow arrow in FIG. 29 ). That is, after the second liquid holder 201 is opened to the atmosphere, concentration by suction filtration continues using only the second filter 422 (S4). That is, the control device 600 continues evacuating the third liquid holder 301. This allows the upper end of the measuring unit 113 to be flush with the liquid level of the microparticle suspension 700. 29 , there is a risk that the liquid level of the microparticle suspension 700 will be sucked to a position below the upper end of the measuring section 113. In contrast, when only the third liquid holding section 301 is sucked and the liquid level of the microparticle suspension 700 reaches the upper end of the measuring section 113, no more of the microparticle suspension 700 will be discharged into the third liquid holding section 301. Incidentally, because the third liquid holding section 301 is under negative pressure, the microparticle suspension 700 will not drip into the second liquid holding section 201. At this time, in order to return the microparticles 701 captured by the second filter 422 to the microparticle suspension 700, the microparticle suspension 700, a cleaning liquid, or the like may be sent to the second filter 422 as shown in FIG.

[0094] Step S3 is the second process. That is, in step S3, the liquid level of the microparticle suspension 700 reaches the vicinity of the lower end of the second hole 421, and thus evacuation of the second liquid holder 201 is stopped. Then, in step S4, evacuation of the third liquid holder 301 continues.

[0095] Furthermore, there are cases where the solution in the microparticle suspension 700 is gradually replaced with a different type of solution. In such cases, after the solution to be replaced is sent to the first liquid holding portion 101, concentration and discharge are repeated in steps S1 to S3. This allows replacement of the solution in the microparticle suspension 700.

[0096] 30, the liquid level of the microparticle suspension 700 is concentrated up to the upper end of the measuring section 113 (reaching the lower end of the second hole), and drainage by the third liquid holding section 301 is no longer performed. The control device 600 then stops suction filtration by the exhaust pump 521 (S5). The control device 600 then switches the second exhaust valve 512 to its atmospheric open side. This also opens the third liquid holding section 301 to the atmosphere (S6). In this way, the concentrated solution can be held at the capacity of the measuring section 113. By concentrating the microparticle suspension 700 up to the measuring section 113 in this way, the liquid volume of the microparticle suspension 700 (concentrated liquid) can be kept constant.

[0097] Step S5 is the third process. That is, in step S5, the liquid level of the microparticle suspension 700 reaches the lower end of the second hole 421, and the evacuation of the third liquid holder 301 is stopped.

[0098] When adding an additive to the microparticle suspension 700, the additive is added to the concentrated microparticle suspension 700 (concentrate) (S7). As a result, as shown in FIG. 31 , the microparticle suspension 700 becomes an additive mixture 721, which is a mixture (liquid) of the microparticle suspension 700 and the additive. Because the volume of the concentrate is constant, the concentration of the additive in the concentrate can be adjusted to a desired concentration by adjusting the amount of additive added. The additive is, for example, an antibacterial agent. The antibacterial agent is added to stop the activity of microorganisms, which are the microparticles 701, in order to confirm whether the solution of the microparticle suspension 700 is affecting them at a predetermined timing. Note that, if the time is short, the solution of the additive mixture 721 will not drip into the second liquid holder 201. Step S7 allows the additive and the microparticle suspension 700 to react with each other in the filtration device 1.

[0099] Next, the control device 600 switches the first exhaust valve 511 to the side of the exhaust pump 521. Then, the control device 600 performs suction using the exhaust pump 521, thereby suctioning the second liquid holding portion 201 (white arrow in FIG. 32 : S8). As a result, the additive mixed liquid 721 is discharged into the second liquid holding portion 201. The discharged liquid 711 becomes a mixed liquid of the microparticle suspension 700 solution and the additive.

[0100] Step S8 is the fourth process. That is, in step S8, the second liquid holding unit 201 is evacuated. In particular, after step S6, when the additive is added to the microparticle suspension 700 in step S7, the second liquid holding unit 201 is evacuated.

[0101] 33, in step S8, all of the solution (wastewater 711) of additive mixed liquid 721 stored in measuring section 113 is collected through first filter 412. As a result, particulates 701 are collected by first filter 412, as shown in FIG.

[0102] When the suction filtration of the additive mixture 721 is completed, the control device 600 stops suction by the exhaust pump 521 (S9). The microparticles 701 collected by the first filter 412 may be modified, including fixation and staining, for microscopic observation. If such modification is performed, the control device 600 stops suction of the second liquid holder 201 and switches the first exhaust valve 511 to the atmospheric open side, as shown in step S9. Then, as shown in FIG. 34 , a liquid reagent 731 is added to the first filter 412 (S10). The reagent 731 is used for modification, such as fixation and staining. Then, the microparticles 701 and the reagent 731 are allowed to react with each other for a desired period of time, as needed. This allows the microparticles 701 and the reagent 731 to react with each other in the filtration device 1. When the reagent 731 is added, liquid delivery may be performed as shown in FIG. 23 or 24 . That is, the tip of the liquid supply nozzle 801 that supplies the reagent 731 is positioned so that the distance between the tip and the first filter 412 is a predetermined position, and then the liquid supply nozzle 801 supplies the reagent 731. As described above, the predetermined position is a position where the supplied reagent 731 does not form bubbles on the surface of the first filter 412. That is, when the liquid reagent 731 is injected from the liquid supply nozzle 801 into the first liquid holding unit 101, the injection is performed in the following procedure. That is, the reagent 731 is injected from the liquid supply nozzle 801 into the first filter 412 from a height at which no bubbles are generated on the surface of the first filter 412.

[0103] After the reaction of the microparticles 701 with the reagent 731, the control device 600 switches the first exhaust valve 511 to the exhaust pump 521, and then performs suction with the exhaust pump 521. This starts suction of the second liquid holder 201 (S11, indicated by the hollow arrow in FIG. 35). As a result of the suction in step S11, the reagent 731 is discharged into the second liquid holder 201, as shown in FIG. 35. When the reagent 731 is to be washed, after the reagent 731 adhering to the microparticles 701 is completely suction-filtered, a cleaning solution (not shown) is sent to the first liquid holder 101, and suction-filtering in step S11 is performed. This allows the reagent 731 adhering to the microparticles 701 to be washed, and the cleaning solution can be discharged into the second liquid holder 201. In this way, the reagent 731 is discharged, the microparticles 701 are washed with the cleaning solution, and the microparticles 701 are dried. The waste liquid 711 is a mixture of the solution of the microparticle suspension 700 , the additive, and the reagent 731 .

[0104] Step S11 is the fifth step. After step S8, a predetermined reagent 731 is added to the particles 701 present on the surface of the first filter 412, and then step S11 is performed.

[0105] 36, when the reagent 731 (or cleaning solution) is completely discharged from the surface of the first filter 412, the user removes the first filter 412 from the filtration device 1 in the procedure shown in Fig. 4 (S12).The user then places the removed first filter 412 under a microscope and observes the first filter 412 through the microscope (S13).

[0106] 27 to 36, the process of delivering the particulate suspension 700, cleaning liquid, etc. to the second filter 422 as shown in FIG. 25 is performed at step S3, but this is not limited to this. As shown in FIG. 25, the process of delivering the particulate suspension 700, cleaning liquid, etc. to the second filter 422 may be performed when the second filter 422 is exposed. That is, the process of delivering the particulate suspension 700, cleaning liquid, etc. to the second filter 422 as shown in FIG. 25 may be performed at any of steps S3 (second step) to S13. However, ideally, the process should be performed at any of steps S3 to S8 (fourth step), or even more ideally, at any of steps S3 to S6 before the additive is added.

[0107] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those having all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0108] For example, as in the second embodiment, a first liquid holder 101 common to a plurality of first holes 411 may coexist, and as in the third embodiment, a first liquid holder 101 corresponding to one of the first holes 411 may coexist. Furthermore, one of the members denoted by reference numeral 132a or 132b in FIG. 11 may be replaced with the first member 100b shown in FIGS. 15 to 18. This makes it easy to achieve a state in which a first liquid holder 101 common to a plurality of first holes 411 and a first liquid holder 101 corresponding to one of the first holes 411 coexist.

[0109] FIG. 37 is a schematic diagram showing another example of the filtration device 1a according to the second embodiment. FIG. 38 is a diagram showing another example of the configuration of a first filter 412a used in the filtration device 1a according to the second embodiment. As shown in FIG. 13 , the first filters 412 may be provided independently to correspond to the respective first holes 411, or may be configured as a single filter, as in the first filter 412a shown in FIG. 37 . In this manner, a first filter 412 (see FIG. 13 ) or a first filter 412a (see FIG. 37 ) is provided for each first hole 411. When the first filter 412a is configured as a single filter, as shown in FIG. 37 , the first filter 412a is provided between the first member 100a and the second member 200. 37, the first member 100a and the second member 200 are separated, but the first member 100a and the second member 200 are in close contact with each other when filtering the particulate suspension 700. Furthermore, when filtering the particulate suspension 700, the first filter 412a is fixed by being sandwiched between the first member 100a and the second member 200, which are in close contact with each other. The first member 100a and the second member 200 are configured such that the particulate suspension 700 to be filtered does not leak even when the first filter 412a is sandwiched between them.

[0110] Furthermore, as shown in FIG. 37, the first member 100a and the second member 200 can be separated, so that the first filter 412a can be easily removed.

[0111] When the first filter 412a is configured as a single filter as shown in Fig. 37, the first filter 412a has a configuration in which a frame 432a is provided around a rectangular filter body 431a as shown in Fig. 38. In this case, as indicated by reference numeral 441 in Fig. 38, the fine particles 701 are collected at locations corresponding to the first holes 411. With the configurations shown in Figs. 37 and 38, multiple collection results can be observed during microscope observation by simply setting the first filter 412a once.

[0112] FIG. 39 is a schematic diagram showing another example of the filtering device 1b according to the third embodiment. As described above, the first filters 412 may be provided independently so as to correspond to the respective first holes 411, or may be configured as a single filter as shown in FIG. 39 . When the first filter 412a is configured as a single filter, as shown in FIG. 39 , the first filter 412a is provided between the first member 100b and the second member 200. Note that although the first member 100b and the second member 200 are separated in FIG. 39 , the first member 100b and the second member 200 are in close contact with each other during filtration of the microparticle suspension 700. Furthermore, during filtration of the microparticle suspension 700, the first filter 412a is fixed by being sandwiched between the first member 100b and the second member 200, which are in close contact with each other. The first member 100b and the second member 200 are configured such that the particulate suspension 700 to be filtered does not leak even when the first filter 412a is sandwiched between them.

[0113] Furthermore, as shown in FIG. 39, the first member 100b and the second member 200 can be separated, so that the first filter 412a can be easily removed.

[0114] As shown in FIG. 39, when the first filter 412a is configured by one filter, the configuration of the first filter 412a and the location where the particulates 701 are collected are the same as those shown in FIG.

[0115] Furthermore, the control device 600 and the like may be realized in part or in whole by hardware, for example, by designing them as integrated circuits. Furthermore, the configuration, functions, and the like of the control device 600 may be realized in software by a processor such as a CPU interpreting and executing programs that realize each function. Information such as programs, tables, and files that realize each function of the control device 600 can be stored in a memory, a recording device such as an SSD (Solid State Drive), or a recording medium such as an IC (Integrated Circuit) card, an SD (Secure Digital) card, or a DVD (Digital Versatile Disc), in addition to being stored on a hard disk (HD).

[0116] In addition, in each embodiment, the control lines and information lines shown are those that are considered necessary for explanation, and not all control lines and information lines in the product are necessarily shown. In reality, it can be considered that almost all components are interconnected.

[0117] DESCRIPTION OF SYMBOLS 1, 1a to 1c Filtration device 100 First member (first container) 101 First liquid holding portion 121 Space (third liquid holding portion) 122 Housing 150 Fourth member (first container) 113 Measuring portion 200 Second member (second container) 201 Second liquid holding portion 300 Third member (second container) 301 Third liquid holding portion 411 First hole 412, 412a First filter 421 Second hole 422 Second filter 431, 431a, 431b Filter body 432, 432a, 432b Frame 501 First exhaust port 502 Second exhaust port 511 First exhaust valve 512 Second exhaust valve 521 Exhaust pump 531 Piping filter 551 Drain pipe 552 Drain recovery unit 553 Suction connection part 600 Control device 700 Microparticle suspension (liquid) 701 Microparticles 711 Drain 721 Additive mixed liquid (liquid, containing additives) 731 Reagent (liquid) 801 Liquid delivery nozzle Z Filtration system S2 Start of concentration (first step) S3 Stop of suction of second liquid holding unit (second step) S4 Concentration (second step) S5 Stop of suction (third step) S8 Suction of second liquid holding unit (fourth step) S11 Start of suction of second liquid holding unit (fifth step)

Claims

1. A filtration device comprising: a first liquid holding portion for holding a liquid to be filtered; a first hole provided in a bottom surface of the first liquid holding portion and a second hole provided in a surface of the first liquid holding portion other than the bottom surface; a second liquid holding portion communicating with the first liquid holding portion via the first hole; and a third liquid holding portion communicating with the first liquid holding portion via the second hole; wherein a first filter is provided in the first hole and a second filter is provided in the second hole.

2. The filtration device according to claim 1, characterized in that the area of ​​the second hole is larger than the area of ​​the first hole.

3. The filtration device according to claim 1, characterized in that there is a predetermined distance between the bottom surface of the first liquid holding portion and the lower end of the second hole.

4. The filtration device described in claim 1, characterized in that the first liquid holding portion is provided in a first container, the second liquid holding portion is provided in a second container that is a container separate from the first container, the first container is detachable from the second container, and the first filter provided in the first hole is detachable by removing the first container from the second container.

5. The filtering device according to claim 1, characterized in that the first filter has a filter body and a frame attached to the outer periphery of the filter body, and the frame has a hardness that allows it to be grasped.

6. The filtering device according to claim 1, characterized in that a plurality of the first holes are provided, and the first filter is provided for each of the first holes.

7. The filtration device according to claim 6, characterized in that the first liquid holding portion, the second hole, and the second filter are provided in common for a plurality of the first holes.

8. The filtration device according to claim 6, characterized in that the first liquid holding portion is provided for each of the plurality of first holes.

9. The filtration device described in claim 8, characterized in that the second hole is provided in a first container together with the first liquid holding portion, and a space which is the third liquid holding portion is provided between the periphery of the second hole and the housing of the first container.

10. A filtration system comprising: a first liquid holding portion for holding a liquid to be filtered; a first hole being provided in a bottom surface of the first liquid holding portion and a second hole being provided in a surface of the first liquid holding portion other than the bottom surface; a second liquid holding portion communicating with the first liquid holding portion via the first hole; and a third liquid holding portion communicating with the first liquid holding portion via the second hole; wherein a first filter is provided in the first hole and a second filter is provided in the second hole; and the second liquid holding portion and the third liquid holding portion are connected to an exhaust pump.

11. A filtration method comprising: a filtration system comprising: a first liquid holding portion for holding a liquid to be filtered; a first hole provided in a bottom surface of the first liquid holding portion and a second hole provided in a surface of the first liquid holding portion other than the bottom surface; a second liquid holding portion communicating with the first liquid holding portion via the first hole; and a third liquid holding portion communicating with the first liquid holding portion via the second hole, wherein a first filter is provided in the first hole and a second filter is provided in the second hole, and the second liquid holding portion and the third liquid holding portion are connected to an exhaust pump, the filtration system comprising: a first step of evacuating the second liquid holding portion and the third liquid holding portion by the exhaust pump when a microparticle suspension containing microparticles is injected into the first liquid holding portion.

12. The filtering method according to claim 11, characterized in that the bottom surface of the first liquid holding portion and the lower end of the second hole have a predetermined distance therebetween, and the filtering system executes, after the first step, a second step of stopping evacuation of the second liquid holding portion and continuing evacuation of the third liquid holding portion when the liquid level of the microparticle suspension reaches near the lower end of the second hole, a third step of stopping evacuation of the third liquid holding portion when the liquid level of the microparticle suspension reaches the lower end of the second hole, and a fourth step of evacuating the second liquid holding portion.

13. The filtration method according to claim 11, further comprising a liquid delivery nozzle capable of injecting the liquid into the first liquid holding portion, and when the liquid is delivered from the liquid delivery nozzle into the first liquid holding portion, the microparticle suspension is delivered from the liquid delivery nozzle to the first filter from a height at which no air bubbles are generated on the surface of the first filter.

14. The filtration method according to claim 12, characterized in that after the third step, an additive is added to the fine particle suspension, and then the fourth step is carried out.

15. The filtration method according to claim 12, further comprising a liquid delivery nozzle capable of injecting the liquid into the first liquid holding portion, the liquid delivery nozzle delivering a predetermined liquid toward the second filter at any timing between the second step and the fourth step.

16. The filtration method according to claim 12, characterized in that after the fourth step, a fifth step is performed in which a specified reagent is added to the fine particles present on the surface of the first filter, and then the second liquid holding section is evacuated.

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