JP2008253916A - Precise filter and precise filtering method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a precise filter and a precise filtering method enabling efficient precise filtration of a dispersion of particulates with clogging prevented reliably. <P>SOLUTION: The precise filter has a filtering vessel 11 receiving a target liquid, a filtering medium 13 arranged at the lower end of the filtering vessel, a filtering container 10 arranged below the filtering medium and having a liquid-receiving vessel 12, and an oscillator 60 oscillating the filtering container 10 so as to cause a stirring flow in the target liquid within the filtering vessel 11. The precise filtering method comprises carries out filtration of a dispersion having an average particle size of dispersoid particles of ≤10 μm and a viscosity of ≤1,000 cps by means of the precision filter. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method and apparatus for performing precise filtration of a fine particle dispersion.

  With recent advances in information technology (IT), it has become a strict requirement to improve the performance, purity, and precision of raw materials, and it is necessary to remove ultra-fine foreign substances and packed particles larger than a predetermined particle size. It has become. Conventionally, a pressure filtration method, a vacuum filtration method, or the like has been adopted to meet this demand. These methods are intended to perform filtration of a dispersion liquid, which is difficult with normal pressure filtration, and are widely implemented. However, in these methods, there are not a few cases where precise filtration is impossible due to properties such as rheology (particularly viscosity, thixotropy) of the dispersion and particle size distribution of the particles. In particular, if particles larger than the passage holes of the filter medium are present in the liquid to be filtered at a high rate, the filter medium will be clogged. Once clogged, the particles that should pass through will also accumulate on the filter medium, and the whole liquid will be filtered. Even if it is possible, only the solvent component passes selectively, and only a treatment liquid different from the original composition can be obtained. Further, when filtration is performed at a strong pressure such as pressurization or decompression, the deposit (filled particles) is pressed against the filter medium by the pressure, and more firmly adheres to the filter medium, which may increase clogging. When such a problem occurs, it is generally handled by changing to a filter medium having a larger passage hole while compromising the quality far from the original requirement.

Under such circumstances, the following method has been proposed from the viewpoint of preventing clogging.
1. Filtration is performed while rotating the blade, and the cake layer deposited by the blade is scraped off.
2. If clogging occurs, reverse the liquid to wash away deposits on the filter media. (Backwash method)
3. Filtering is performed by continuously applying a slight vibration (vibration) to alleviate clogging of the filter medium.

However, in 1 above, the filter medium is easily damaged, and in 2 above, the clogging prevention effect is not sufficiently obtained. Regarding method 3, various methods and apparatuses have been proposed (Patent Documents 1 to 3). Among these, the apparatus of Patent Document 1 applies vibration to the filter portion by a piezoelectric vibrator or an electromagnetic vibrator, and the amplitude is small due to the vibration principle. As a result, this apparatus only removes bubbles in the liquid and does not have a sufficient effect for preventing clogging. The apparatus of Patent Document 2 vibrates a chamber containing a filter with an ultrasonic vibrator, and in the fine vibration due to ultrasonic vibration, the concentration of fine particles of the liquid to be filtered increases near the filter, and the filtration speed decreases. To do. The thing of patent document 3 is a sieving apparatus which sifts a large particle like coagulum in latex with a screen, and vibrates a sieving frame. However, when the screen exceeds 400 mesh, it is said that clogging occurs.
Is,
Japanese Patent No. 2570168 Special table 2000-501651 gazette Japanese Utility Model Publication No.59-131216

  An object of the present invention is to provide a filtration apparatus and a filtration method capable of efficiently performing precise filtration of a fine particle dispersion while reliably preventing clogging.

  In order to achieve the above object, the present invention provides a filtration vessel comprising a filtration tank that receives a liquid to be filtered, a filter medium provided at the lower end of the filtration tank, and a liquid receiving tank provided below the filter medium. The present invention also provides a microfiltration apparatus comprising a vibration device for shaking the filtration container so as to generate a stirring flow in the liquid to be filtered in the filtration tank.

  In order to achieve the above object, the present invention is also a microfiltration method for a dispersion having an average particle diameter of dispersed particles of 10 μm or less and a viscosity of 1000 cps or less, a filtration tank for receiving a liquid to be filtered, and the filtration Precision characterized by shaking a filtration container provided with a filter medium provided at the lower end of the tank and a liquid receiving tank provided below the filter medium so as to generate a stirring flow in the liquid to be filtered A filtration method is provided.

  The microfiltration device according to the present invention is for filtering a filtration container provided with a filtering medium between a filtration tank and a liquid receiving tank, and for shaking the filtration container so as to generate a stirring flow in the liquid to be filtered in the filtration tank. Therefore, both the filtration container and the filter medium are shaken, and the liquid to be filtered flows greatly in the vicinity of the filter medium. Thereby, the fine particles adhering so as to close the eyes of the filter medium are immediately separated from the filter medium, and the filter medium is reliably prevented from being clogged. In conventional static pressure filtration, deposits may adhere more strongly to the filter medium due to pressurization, and on the contrary, filtration may be difficult, but according to the present invention, the pressure due to shaking is shocking and Since it acts repeatedly intermittently, it is difficult to cause strong deposition. Further, the shaking is performed so as to generate a stirring flow in the liquid to be filtered in the filtration tank, so that the concentration of fine particles in the liquid to be filtered is made uniform, and the increase in the concentration of fine particles in the vicinity of the filter medium and the accompanying filtration efficiency. Is prevented, and efficient microfiltration can be maintained. Furthermore, in the case of a liquid to be filtered having thixotropy, the viscosity is lowered by the stirring action of shaking, and filtration is promoted more efficiently.

In the microfiltration method according to the present invention, the above microfiltration apparatus is used for microfiltration of a dispersion having an average particle diameter of 10 μm or less and a viscosity of 1000 cps or less, and a stirring flow is generated in the liquid to be filtered. Therefore, it is possible to obtain the above-described filtration efficiency and prevention of clogging with a microfiltration device, and clogging even in the case of a dispersion having the above average particle diameter and viscosity of the dispersed particles that are likely to clog. Thus, it is possible to efficiently perform microfiltration.
[Preferred forms of the invention]
The apparatus and method of the present invention exhibit a particularly high clogging prevention effect that has not been obtained conventionally when the filter medium has a filter surface with an opening of 20 μm or less. This high clogging prevention effect is further significantly obtained when a filter medium having an opening of 3 to 10 μm is used.

  The shaking in the apparatus and method of the present invention is performed so as to generate a stirring flow in the liquid to be filtered in the filtration tank 11, and for that purpose, the filtration container 11 is 10 mm or more and the maximum inner dimension of the filtration tank. It is desirable to vibrate with a small amplitude. If the amplitude is less than this lower limit, the liquid to be filtered is not properly stirred and the filter medium 13 may not be sufficiently prevented from being clogged. Further, when the amplitude exceeds the above upper limit, the effect of preventing clogging obtained does not increase for an increase in the load of the driving mechanism and the increase in the size of the apparatus. From this viewpoint, it is more desirable that the vibration amplitude of the filtration container is 20 mm or more and a value smaller than ½ of the maximum inner dimension of the filtration tank.

  The maximum inner dimension of the filtration tank refers to the dimension of the largest inner part of the filtration tank in the filtration container. For example, when the filtration tank is a rectangular parallelepiped, it is the distance connecting the farthest corners on the inner surface. When the filtration tank is cylindrical, on the inner surface, the distance from the intersection of a part of the side surface and one end surface to the intersection of the opposite side surface portion and the other end surface (distance passing diagonally through the cylinder) Become.

  Further, it is desirable that the filtration container is vibrated at a vibration frequency of 20 to 2000 cycles / min. If the vibration frequency is less than this lower limit, the flow of stirring of the liquid to be filtered does not occur appropriately, and the effect of preventing clogging of the filter medium 13 may not be sufficiently obtained. Further, when the amplitude exceeds the above upper limit, the effect of preventing clogging obtained does not increase for an increase in the load of the driving mechanism and the increase in the size of the apparatus. From this viewpoint, it is more preferable that the vibration frequency of the filtration container is 30 to 300 cycles / minute.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The same or similar parts in the drawings may be denoted by the same reference numerals and description thereof may be omitted.

  FIG. 1 schematically shows an embodiment of a microfiltration apparatus according to the present invention. This microfiltration device includes a filtration vessel 10 having a filtration tank 11 for receiving a liquid to be filtered, a filter medium 13 provided at the lower end of the filtration tank, and a liquid receiving tank 12 provided below the filter medium. I have.

  The filtration container 10 can have various shapes such as a cylindrical shape such as a circular shape, an oval shape, and a polygonal cross section, a cone shape, a truncated cone shape, and a rectangular parallelepiped shape. Moreover, a dimension and a capacity | capacitance can be suitably determined according to the processing amount etc. of to-be-filtered liquid. In this embodiment, the filtration container 10 has a cylindrical shape and is divided into two parts so as to be separable in the axial direction. The lower end is closed, and a detachable lid 110 is provided at the upper end.

  The filtration tank 11 is formed by a divided upper cylindrical portion, and a supply cylinder 111 for supplying a liquid to be filtered is provided near the upper end. The liquid receiving tank 12 is formed of a lower cylindrical portion, and its upper end is fitted to the lower end of the filtration tank 11 so as to be removable. A discharge cylinder 120 extends downward from the lower end of the liquid receiving tank 12. The filtration tank 11 and the liquid receiving tank 12 can be made of metal, plastic, or the like, and are desirably made of metal in order to prevent thermal deformation.

  The filter medium 13 is attached to the lower end portion of the filtration tank 11. As the filter medium, various filters for fine filtration such as a filter cloth made of woven fabric or knitted fabric, a porous membrane made of a polymer material, a metal filter, or the like can be used. Among these, since the filter cloth has a simple flow path of the treatment liquid through the filtration opening, high productivity of the filtration treatment can be obtained. The porous membrane can be subjected to highly precise filtration with a fine mesh and has a high aperture ratio. The metal filter has high mechanical strength and excellent durability against vibration.

  The opening of the filter surface of the filter medium is determined according to the required size of the passing particle diameter. In particular, in the case of an opening of 20 μm or less, a higher clogging prevention effect is exhibited as compared with the conventional case. In order to attach the filter medium 13 to the filter tank 11, various commonly used means such as disposing the filter medium at the open end of the filter tank and fixing the holding ring in an overlapping manner can be used.

  The filtration container 10 is accommodated in a heat insulation box 30, and the heat insulation box 30 includes a bottom wall 31, a side wall 32, and an upper wall 33, and forms a heat insulation inside. A frame 40 for supporting the filtration container 10 is supported on the bottom wall of the heat retaining box 30 via a movable mechanism 50. The heat retaining box 10 is desirably a sealed type with a temperature adjustment function in order to lower the viscosity of the processing liquid and increase the processing efficiency, and the temperature setting function is variable so that the temperature can be set from room temperature to about 200 ° C. A mold is preferred. When the liquid to be filtered contains an organic solvent in the solvent, treatment at a low temperature is desirable from the viewpoint of safety. When the liquid to be filtered uses a resin-based material as the solvent, the temperature at which the resin decomposes is set. In general, the treatment is often performed at a temperature around 120 ° C. as the limit.

  The frame 40 includes a flat shaking table 41 and a support portion 42, and the filtration container 10 is supported and fixed on the support portion 42. Fixing can be performed by an appropriate means such as a fixing bolt. Since the optimum value of the installation angle of the filtration container 10 varies depending on the properties of the treatment liquid, the frame 40 is preferably configured to be able to change the installation angle of the filtration container 10 and the angle θ of the filtration container 10 with respect to the horizontal plane is set to 0 °. It is desirable to make it variable from 90 ° to 90 °. For this purpose, the support part 42 can be exchanged with another inclined part, or the support part 42 can be expanded or contracted, or the fixed height of the filtration container 10 relative to the support part extending in the vertical direction can be adjusted. Etc. can be adopted.

  The movable mechanism 50 includes a link device 51 and a guide unit 52. A pair of link devices 51 are provided near the front and rear ends of the bottom wall 31 and the shaking table 41 (in the drawing, both ends in the depth direction of the drawing). Each link device 51 includes two link pieces 511 and 512 that are rotatably connected to each other, and are rotatably connected to the bottom wall 31 and the shaking table 41 to form link pieces 511 and 512. Two pairs of links are provided at a distance, and a horizontal link 513 is further rotatably coupled to a connection point between the link pieces 511 and 512 of each pair, thereby forming a parallel link mechanism. The guide portion 52 extends in the vertical direction so as to lightly contact the edge of the shaking table 41 and is provided at the front, rear, left and right ends of the shaking table 41 to guide the shaking table 41 in the vertical direction. .

  The microfiltration device further includes a vibration device 60 for shaking the filtration container 10. The vibration device 60 includes a drive motor 61 installed outside the heat retaining box 30, a pulley 62 coupled to the shaft of the drive motor, a cylinder 63 fixed to the bottom wall 31 of the heat retaining box 30 and extending in the vertical direction, the cylinder The piston 64 which slides inside, and the connecting rod 65 which connects the pulley 62 and the piston 64 are provided. The upper end of the piston 64 is firmly fixed to the shaking table 41 of the frame 40. The connecting rod 65 has an upper end coupled to the lower end of the piston 64 and a lower end coupled to the pulley 62. A plurality of coupling holes are arranged in the radial direction in the pulley 62 so that the connecting rod 65 can be coupled by changing the distance from the rotation shaft (not shown). The rotation of the drive motor 61 is transmitted to the piston 64 through the pulley 62 and the connecting rod 65, and the piston 64 is repeatedly slid in the vertical direction with respect to the cylinder 63. Therefore, the frame 40 coupled to the piston 64 also moves up and down, and the up and down movement is translated in the vertical direction by the link device 51 and the guide portion 52. As a result, the filtration container 10 supported by the frame 40 also moves up and down repeatedly, and the container and its contents are shaken.

  The amplitude of the vibration can be changed by changing the separation distance from the rotation axis with respect to the pulley 62 and coupling the lower end 650 of the connecting rod 65. In this embodiment, the amplitude can be varied in the range of 10 to 200 mm.

  Further, the vibration frequency (vibration speed) of the shake can be changed by changing the rotation speed of the drive motor 61. In this embodiment, the rotational speed of the drive motor 61 is variable so that a desired frequency of 30 to 300 cycles / minute can be obtained.

  A liquid storage tank 70 for the liquid to be filtered is disposed above the heat retaining box 30. A discharge tube 71 extends from the lower end of the liquid storage tank 70 through an opening provided in the upper wall 33 of the heat retaining box 30, and its tip is connected to the supply cylinder 111 of the filtration tank 11. In addition, an opening / closing valve 72 is provided in the middle of the discharge tube 71, and the liquid to be filtered to the filtration tank 11 can be supplied and stopped by opening / closing the opening / closing valve 72. The discharge tube 71 is flexible and has a necessary length so as to allow the supply cylinder 111 connected to the discharge tube to move with the shaking of the filtration container 10.

  A recovery tank 80 is disposed below the heat retaining box 30. An infusion tube 81 is connected to the lower end of the discharge cylinder 120 of the liquid receiving tank 12, and the infusion tube 81 extends through an opening provided in the bottom wall 31 of the heat retaining box 30, and is located at the upper end of the recovery tank 80. It is connected to the receiving port 83. Therefore, the filtrate that has passed through the filter medium 13 is stored in the collection tank 80 from the liquid receiving tank 12 through the infusion tube 81. The infusion tube 81 is flexible and has a required length so as to allow the discharge cylinder 120 connected to the infusion tube to move with the shaking of the filtration container 10.

  In order to use this apparatus, the liquid to be filtered is put into the liquid storage tank 70, the on-off valve 72 is opened and supplied to the filtration tank 11, and the drive motor 61 is operated. As a result, the filtration container 10 is shaken, and filtration that is efficient and prevents clogging of the filter medium becomes possible. The filtrate that has passed through the filter medium 13 flows out of the liquid receiving tank 12 and is stored in the collection tank 80. The filtration process is a batch process that is performed by closing the on-off valve 72 when a predetermined amount of the liquid to be filtered is supplied to the filtration tank 11, and the liquid to be filtered is continuously supplied at a predetermined speed without closing the on-off valve 72. Any of the continuous processes can be performed.

  When performing the filtration treatment, it is desirable to find the optimum attachment angle of the filtration container, the amplitude of vibration, the vibration frequency, etc. according to the liquid to be filtered, and to carry out the filtration treatment under optimum conditions. In the case of a material that is difficult to obtain a high effect by filtration at normal pressure, the filtration efficiency can be increased by using a pressurization method or a decompression method in combination. This device, for example, exhibits an excellent effect in filtration of adhesives containing filler materials such as silica among IT materials, but the type of filler contained in the liquid to be filtered can be either organic or inorganic materials. However, various solvents can be treated as long as the solvent is a liquid including an organic solvent, a resin material, and water. Moreover, the usage can be used in a wide range such as removal of foreign substances, removal of particles having a predetermined diameter or more, and classification of particles.

  FIG. 2 schematically shows another embodiment of the microfiltration apparatus according to the present invention. This microfiltration apparatus has substantially the same structure as the apparatus shown in FIG. However, this embodiment has a structure in which the filtration container 10 is shaken in the horizontal direction. For this purpose, the vibration exciter 60a includes a drive motor 61 installed on the bottom wall 31 of the heat retaining box 30, a pulley 62 coupled to the shaft of the drive motor, and a cylinder 63 fixed to the bottom wall 31 and extending in the horizontal direction. The piston 64 that slides in the cylinder and the connecting rod 65 that connects the pulley 62 and the piston 64 are provided. A connecting piece 66 extends upward from the piston 64, and a groove extending in the axial direction is formed in the cylinder 63. The connecting piece 66 slides in the groove along with the piston 64. The upper end of the connection piece 66 is firmly fixed to the shaking table 41 of the frame 40. One end of the connecting rod 65 is coupled to the lower end portion of the piston 64, and the other end is coupled to the pulley 62. These coupling structures are the same as those in FIG.

  The movable mechanism 50a that supports the frame 40 is constituted by a guide portion 52a. The guide part 52a is a member extending in the horizontal direction, and supports the shaking table 41 so as to be slidable in the horizontal direction while gently holding the shaking table 41 in the vertical direction. A pair of guide portions 52 a are provided at both front and rear end portions (both end portions in the depth direction of the paper surface) of the shaking table 41, thereby stably supporting the frame 40.

  With this structure, the rotation of the drive motor 61 is transmitted to the piston 64 via the pulley 62 and the connecting rod 65, and the piston 64 is repeatedly slid in the horizontal direction with respect to the cylinder 63. Move. As a result, the filtration container 10 supported by the frame 40 also repeats horizontal movement, and the container and its contents are shaken.

  Desirable ranges of vibration amplitude and frequency are similar to those in the apparatus of FIG. As shown in the figure, the direction of shaking may be a direction along a plane including the axis of the filtration container 10, or may be a direction perpendicular to the plane or inclined at a predetermined angle.

  FIG. 3 schematically shows still another embodiment of the microfiltration apparatus according to the present invention. This microfiltration apparatus also has substantially the same structure as the apparatus shown in FIG. In this embodiment, the vibration device 60b has a structure in which the filtration container 10 is shaken so as to draw a circular motion along the vertical plane.

  Therefore, the movable mechanism 50b that supports the frame 40 includes a support plate 53 erected on the bottom wall 31 in the vicinity of both front and rear end portions (both end portions in the depth direction of the paper surface) of the shaking table 41, and the support plate. And a pair of levers 54 supported at both left and right ends of each of the levers 54. Each lever 54 is pivotally supported on the support plate 53 by a fulcrum 541 at one end and on the shaking table 41 by a fulcrum 542 at the other end. Thereby, the shaking rack 41 can move so as to draw a circular motion by the rotation of the lever 54 around the fulcrum 541.

  The vibration device 60b in this embodiment includes a drive motor 61 installed on the bottom wall 31 of the heat retaining box 30, and a pulley 62 coupled to the shaft of the drive motor. A part of the shaking table 41 is extended to the position of the pulley 62 to form a coupling portion 410, and the pulley 62 is coupled to the coupling portion 410 by a pin 620.

  With this structure, when the drive motor 61 rotates, the accompanying rotation of the pulley 62 causes a circular motion of the shaking table 41 via the pin 620. As a result, the filtration container 10 supported by the frame 40 also repeats the circular motion, and the container and its contents are shaken. A plurality of coupling holes are arranged in the radial direction in the pulley 62 so that the pins 620 can be coupled at different distances from the rotating shaft (not shown). The lever 54 is also provided with a plurality of engagement holes so that the distance between the fulcrums 541 and 542 can be changed. Therefore, by changing the positions of the pin 620 and the fulcrum 541 or 542, the turning radius of the circular motion to be drawn can be changed, and the amplitude of tremor can be changed.

  Desirable ranges of vibration amplitude and frequency are similar to those in the apparatus of FIG. As shown in the figure, the direction of shaking may be a direction along a plane including the axis of the filtration container 10, or may be a direction perpendicular to the plane or inclined at a predetermined angle.

  The present invention is not limited to the above embodiment, and various modifications can be made. The frame that supports the filtration container, the movable mechanism that movably supports the frame, and the vibration exciter that shakes the filtration container can have various structures that have the same function in addition to the above embodiment. In the said embodiment, although the filtration container was inclined and supported, you may install this vertically or horizontally. In these cases as well, the shaking direction can be set in various directions such as parallel, vertical, and diagonal with respect to the axis of the filtration container.

  In order to confirm the effect of the present invention, the experiment according to the embodiment according to the present invention and the comparative example by the conventional method were conducted. In both the examples and the comparative examples, a stainless steel container having a diameter of 15 cm and a length of 35 cm is used as a filtration container. Installed at °. In the examples, horizontal shaking was applied using the filtration device shown in FIG. On the other hand, in the comparative example, when the filtration container was vibrated, the filtration container was placed on the Dalton vibrating sieve to give vibration. The filtration process was continuously performed, and the weight of the filtrate in the collection tank was measured every 30 minutes, 60 minutes, and 90 minutes, and used as an integrated filtration amount.

The following three kinds of liquids to be filtered were used, and 6 kg was first stored in a filtration tank.
Liquid A: 60% aqueous dispersion of spherical silica having an average particle diameter of 18 μ containing 5% by weight of coarse particles of 40 μ or more B: 40% water of spherical silica having an average particle diameter of 1 μ containing 4% by weight of coarse particles of 5 μ or more Dispersion liquid C: Epoxy resin (Epiclon 830: manufactured by Dainippon Ink & Chemicals, Inc.) in which 20% by weight of spherical silica having an average particle diameter of 1 μ containing 4% by weight of coarse particles of 5 μm or more was dispersed at 100 ° C. Heated [Example 1]
Filter medium: 40μ nylon nylon filter cloth Filtrate: Liquid A
Filtration conditions: Amplitude 4 cm, shaking horizontally at a frequency of 60 times / minute Temperature in the heat insulation box: normal temperature (25 ° C.)
[Example 2-1]
Filter media: Nylon filter cloth with 10μ mesh opening Filtration liquid: Liquid B
Filtration conditions: Amplitude 4 cm, shaking horizontally at a frequency of 60 times / minute Temperature in the heat insulation box: normal temperature (25 ° C.)
[Example 2-2]
Filter media: Nylon filter cloth with 10μ mesh opening Filtration liquid: Liquid B
Filtration conditions: Amplitude 12 cm, shaking horizontally at a frequency of 60 times / minute Temperature in the heat insulation box: normal temperature (25 ° C.)
[Example 3]
Filter media: Nylon filter cloth with opening 10μ Filtered liquid: Liquid C
Filtration conditions: Amplitude 12 cm, shaking in the horizontal direction at a frequency of 60 times / minute Temperature in the heat insulation box: 100 ° C.
[Comparative Example 1-1]
Filter medium: 40μ nylon nylon filter cloth Filtrate: Liquid A
Filtration conditions: Pressurize the filtration tank to 2 atmospheres (no shaking)
[Comparative Example 1-2]
Filter medium: Nylon filter cloth with an opening of 40μ Filtered liquid: Liquid A
Filtration conditions: Exciting up and down at an amplitude of 3 mm and a frequency of 60 Hz [Comparative Example 2-1]
Filter medium: Nylon filter cloth with 10μ mesh opening Filtration liquid: Liquid B
Filtration conditions: Pressurize the object tank to 2 atm (no shaking)
[Comparative Example 2-2]
Filter medium: Nylon filter cloth with 10μ mesh opening Filtration liquid: Liquid B
Filtration conditions: Amplification up and down at an amplitude of 3 mm and a frequency of 60 Hz [Comparative Example 3-1]
Filter medium: Nylon filter cloth with 10μ mesh opening Filtration liquid: Liquid C
Filtration conditions: Pressurize the filtration tank to 2 atmospheres (no shaking)
[Comparative Example 3-2]
Filter medium: Nylon filter cloth with 10μ mesh opening Filtration liquid: Liquid C
Filtration conditions: Vibration up and down with an amplitude of 3 mm and a frequency of 60 Hz [Result]
Table 1 shows the accumulated filtration amount for each of the examples and comparative examples for each elapse of a predetermined time.

The above results show the following states. Comparing with the same type of liquid to be filtered, the integrated filtration amounts of Examples 1, 2-1, 2-2, and 3 were 30 minutes, 60 minutes, and 90 minutes after the start of treatment. The total filtration amount of 1-2, 2-1, 2-2, 3-1, 3-2 greatly exceeds. In the embodiment, the integrated filtration amount increases almost in proportion to the elapsed time. However, in the comparative example, the increase amount of the integrated filtration amount significantly decreases as the processing time elapses. Therefore, it is clear that the example has better filtration efficiency than the comparative example, and the reduction in filtration efficiency due to clogging is extremely small. As described above, according to the microfiltration method and apparatus of the present invention, it has become possible to realize high performance and reliability of a dispersed product that has been conventionally required but could not be achieved.

1 is a longitudinal sectional view schematically showing one embodiment of a microfiltration apparatus according to the present invention. It is a longitudinal cross-sectional view which shows schematically other embodiment of the microfiltration apparatus which concerns on this invention. It is a longitudinal cross-sectional view which shows schematically further another embodiment of the microfiltration apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Filtration container 11 Filtration tank 12 Receiving tank 13 Filter medium 30 Thermal insulation box 40 Frame 41 Shaking table 50, 50a, 50b Movable mechanism 60, 60a, 60b Excitation apparatus 70 Liquid storage tank 80 Collection tank

Claims (8)

A filtration tank comprising a filtration tank for receiving a filtrate, a filter medium provided at the lower end of the filtration tank, a liquid receiver tank provided below the filter medium, and a liquid to be filtered in the filtration tank A microfiltration apparatus comprising a vibration device for shaking the filtration container so as to generate a stirring flow. 2. The microfiltration apparatus according to claim 1, wherein the filter medium has a filter surface with an opening of 20 [mu] m or less. The microfiltration device according to claim 1 or 2, wherein the vibration device vibrates the filtration container with an amplitude of 10 mm or more and smaller than a maximum inner dimension of the filtration tank. 4. The microfiltration device according to claim 1, wherein the vibration device vibrates the filtration container at a frequency of 20 to 2000 cycles / minute. A method for microfiltration of a dispersion liquid having an average particle diameter of 10 μm or less and a viscosity of 1000 cps or less, a filtration tank for receiving a liquid to be filtered, a filter medium provided at a lower end of the filtration tank, A microfiltration method comprising shaking a filtration container provided with a liquid receiving tank provided below a filter medium so as to generate a stirring flow in a liquid to be filtered. 6. The microfiltration method according to claim 5, wherein a filter having a filter surface with an opening of 20 [mu] m or less is used as the filter medium. The microfiltration method according to claim 5 or 6, wherein the filtration container is shaken with an amplitude of 10 mm or more and smaller than a maximum inner dimension of the filtration tank. The microfiltration method according to any one of claims 5 to 7, wherein the filtration container is shaken at a frequency of 20 to 2000 cycles / minute.