Double structured gel filtration filter

Abstract

To solve the problem that when a capture object of a filter cartridge is a gel-like object, the gel-like object having been captured once moves in a filtration material, and may flow out to a secondary side.SOLUTION: A filter cartridge formed into such a cylindrical shape as to flow a fluid from an outer peripheral side to an inner peripheral side has an outer cylinder arranged on the outermost periphery, a pleat filtration material which is arranged on an inner peripheral side of the outer cylinder and is formed into a pleat shape, a middle cylinder arranged on the inner peripheral side of the pleat filtration material, a net material arranged on the inner peripheral side of the middle cylinder, a wound filtration material which is arranged on the inner peripheral side of the net material and is formed by winding a non-woven fabric, an inner cylinder arranged on the inner peripheral side of the wound filtration material, and end plates which cover both ends from the outer cylinder to the inner cylinder and are arranged on upper and lower sides of the outer cylinder and the inner cylinder, and thereby can suppress re-outflow of a captured gel-like object.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a filter cartridge suitable for capturing gel-like matter. [Background technology]

[0002] In order to remove dust and mist from gas, solids suspended in liquid, etc., filter cartridges are used in which the filter material is formed into a cylindrical shape and the fluid passes from the outer periphery (primary side) to the inner periphery (secondary side) of the cylinder. Such filter cartridges include so-called depth filters, in which a cylinder is formed by winding a nonwoven fabric made of thermoplastic resin or glass fiber, and pleated filters, in which the filter material is pleated to increase the filtering area of ​​the filter material and thereby reduce the initial pressure loss caused by the passage of the fluid (e.g., Patent Document 1 and Patent Document 2).

[0003] Depth filters aim to prevent overall clogging and extend the filter life by retaining the objects to be captured in the fluid not only on the surface of the cylinder but also inside the radial thickness. In contrast, pleated filters capture objects to be filtered mainly on the surface of the filter material. By increasing the surface area of ​​the filter material, pleated filters can reduce the flow rate per unit area and therefore the initial filtration differential pressure.

[0004] While depth filters are able to hold a large amount of the target substance in the filter material, they have the disadvantage that the filtration pressure difference is high. In addition, pleated filters have the disadvantage that the filter material becomes clogged relatively rapidly when the target substance accumulates on the surface of the filter material, resulting in a short filter life. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-049413 [Patent Document 2] Japanese Patent Application Publication No. 7-213814 [Patent Document 3] Utility Model Publication No. 7-9414 [Patent Document 4] Patent Publication No. 2010-137121 Summary of the Invention [Problem to be solved by the invention]

[0005] The objects to be filtered by such filter cartridges are not limited to solids such as the JIS test dust described in the examples of Patent Documents 1 and 3, and the AC fine dust described in the examples of Patent Document 2, but may also include gel-like substances (aggregates) such as undissolved polymers and emulsions. Patent Document 4, for example, is an example of a filter cartridge that captures gel-like substances.

[0006] When the filter cartridge is intended to capture a gel-like material, the gel-like material has a certain degree of fluidity, and therefore, due to an increase in the pressure difference between the primary and secondary sides of the filter material or pulsation of the passage resistance of the fluid to be filtered, the gel-like material that was once captured may move through the filter material and flow out to the secondary side. [Means for solving the problem]

[0007] In order to solve this problem, the present invention provides a filter cartridge formed in a cylindrical shape that allows fluid to flow from the outer periphery to the inner periphery, the filter cartridge having an outer tube arranged on the outermost circumference, a pleated filter material arranged on the inner periphery of the outer tube and formed in a pleats shape, a middle tube arranged on the inner periphery of the pleated filter material, a net material arranged on the inner periphery of the middle tube, a rolled filter material arranged on the inner periphery of the net material and formed by rolling a nonwoven fabric, an inner tube arranged on the inner periphery of the rolled filter material, and end plates that cover both end portions from the outer tube to the inner tube and are arranged above and below the outer tube and the inner tube.

[0008] By using a filter cartridge having this configuration, it is possible to capture the gel-like matter within the filter cartridge and prevent the captured gel-like matter from flowing out to the secondary side.

[0009] The rolled filter material is preferably a laminated nonwoven fabric in which nonwoven fabrics having different average fiber diameters are laminated together. By using a nonwoven fabric of this configuration, the amount of the target material to be captured by the rolled filter material can be increased, and the filter life can be extended.

[0011] The laminated nonwoven fabric is preferably a laminated nonwoven fabric in which a nonwoven fabric A having an average fiber diameter of 0.6 to 1.0 μm and a nonwoven fabric B having an average fiber diameter of 0.1 to 0.5 μm are laminated in the order of nonwoven fabric A-nonwoven fabric B-nonwoven fabric A. By using a nonwoven fabric of this configuration, the amount of gel-like material retained can be increased, and the outflow of the gel-like material to the secondary side can be effectively prevented.

[0012] The rolled filter material is preferably a nonwoven fabric with a porosity of 60 to 75%. By having a porosity in this range, it is possible to increase the amount of gel-like material retained while suppressing the initial pressure loss of the filter cartridge, thereby effectively preventing the gel-like material from leaking to the secondary side. Effect of the Invention

[0013] In the filter cartridge of the present invention, the pleated filter material captures solids and gelatinous matter from the fluid to be treated with high precision. As the amount of processing increases, the solids captured and accumulated on the surface of the pleated filter material increase the resistance to liquid flow through the filter cartridge, but as the amount of captured gelatinous matter increases, the surface area of ​​the captured gelatinous matter also increases. In this case, the resistance of the captured gelatinous matter to the fluid to be treated increases, causing the captured gelatinous matter to deform and disperse, and flow out to the secondary side of the pleated filter material.

[0014] However, the gel-like matter that has flowed out to the secondary side of the pleated filter material is captured by the wound filter material and held within its volume, thereby preventing the gel-like matter from flowing out to the secondary side of the filter cartridge.

[0015] Furthermore, by having a net material between the middle cylinder and the wound filter material, the filter cartridge of the present invention can prevent uneven clogging of the wound filter material and suppress an increase in the fluid resistance of the filter cartridge, thereby extending the service life of the filter cartridge compared to a filter cartridge without the net material.

[0016] The center cylinder is subjected to pressure generated by clogging of the pleated filter media, and therefore has a smaller total area of ​​openings than the outer cylinder to prevent the filter cartridge from collapsing. If the fluid to be treated locally flows into the wound filter media through the openings, clogging of the wound filter media near the openings will cause the pressure difference in the filter cartridge to rise in a short period of time.

[0017] In order to suppress this increase in differential pressure, the filter cartridge of the present invention has a net material disposed between the middle cylinder and the rolled filter material. The fluid to be treated that flows out of the middle cylinder is dispersed by the gaps formed by the net material before flowing into the rolled filter material. This allows the fluid to flow into the rolled filter material from the entire outer periphery of the rolled filter material, suppressing localized clogging of the rolled filter material. [Brief description of the drawings]

[0018] [Figure 1] FIG. 2 is a diagram illustrating a cross-sectional configuration of the filter cartridge of the present invention. [Diagram 2] FIG. 2 is a diagram illustrating the configuration of a filter cartridge of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] As shown in Figures 1 and 2, the filter cartridge 1 of the present invention is composed of, from the inflow side (primary side) of the fluid to be treated, an outer cylinder 2, pleated filter material 3, a middle cylinder 4, a net material 5, rolled filter material 6, an inner cylinder 7, and end plates 8 and 9 that seal each of the cylindrical components to prevent the fluid to be treated from flowing out from the upper and lower openings of these components.

[0020] The outer cylinder 2 is a cylindrical material having a plurality of openings 10, through which the fluid to be treated passes from its outer periphery to its inner periphery. The outer cylinder 1 shown in Fig. 2 is a molded product made of a thermoplastic resin and has a relatively high strength, but since the passage of the fluid to be treated through the outer cylinder 1 is unlikely to cause an increase in resistance to the passage of the fluid, the outer cylinder may be wrapped with a net material or a coarse nonwoven fabric that does not cause clogging, depending on the application of the filter cartridge.

[0021] Various configurations can be used for the pleated filter material 3 depending on the fluid to be treated and the object to be captured. For example, a cylindrical pleated filter material can be made by pleating (mountain folding) a laminate of melt-blown nonwoven fabric, spunbond nonwoven fabric, or a net material used for maintaining the shape after pleating, and then heat welding both ends of the pleated cloth.

[0022] The middle cylinder 4 is a cylindrical material with multiple openings 11, and allows the fluid to pass through from its outer periphery to its inner periphery. It is mainly made of thermoplastic resin or metal, and prevents the pleated filter material 3 from buckling or the filter cartridge from collapsing due to the pressure difference between the primary and secondary sides of the pleated filter material 3 caused by clogging of the pleated filter material 3.

[0023] The net material 5 is arranged to maintain a gap between the middle cylinder 4 and the rolled filter material 6 described below, and its material, mesh size, and the thickness of the wire material constituting the net can be selected according to the fluid to be treated and the object to be captured.

[0024] Normally, the middle cylinder 4 has the strength to withstand the pressure difference that occurs when the fluid to be treated passes through the pleated filter material 3, but when the pleated filter material 3 captures the target substance, the increased pressure difference causes some deformation, and the middle cylinder 4 comes into contact with the rolled filter material 6 described below, and if the pressure difference increases further, the middle cylinder 4 may press against the rolled filter material 6. In such a case, the fluid to be treated only passes locally near the opening 10 of the rolled filter material 6, and if part of the rolled filter material 6 becomes clogged, the pressure difference in the filter cartridge 1 increases, making it unusable.

[0025] The net material 5 is used to effectively utilize the rolled filter material 6, and is arranged to maintain an appropriate gap between the middle cylinder 4 and the rolled filter material 6 even when the middle cylinder 4 is deformed. That is, the fluid to be treated that flows into the inner periphery of the middle cylinder 4 through the opening 10 from the outer periphery of the middle cylinder 4 is dispersed from the radial direction to the circumferential direction of the middle cylinder 4 by the net material 5, and flows into the rolled filter material 6 after the dispersion, so that the fluid flows into the rolled filter material 6 from almost the entire outer periphery of the rolled filter material 6. This prevents local clogging of the rolled filter material 6, and effectively utilizes the front volume of the rolled filter material 6 to hold the object to be captured that flows out of the pleated filter material 3 inside the rolled filter material 6.

[0026] The rolled filter material 6 is made by rolling a nonwoven fabric made of a thermoplastic resin such as polypropylene (PP), polyethylene terephthalate (PET), or polyamide (PA) once or multiple times, and in the present invention, it has the main effect of capturing gel-like matter that has flowed out to the secondary side of the pleated filter material 3.

[0027] The rolled filter material 6 is preferably constructed by laminating a nonwoven fabric A having an average fiber diameter of 0.6 to 1.0 μm and a nonwoven fabric B having an average fiber diameter of 0.1 to 0.5 μm in the order of nonwoven fabric A - nonwoven fabric B - nonwoven fabric A. It has been experimentally confirmed that the use of a nonwoven fabric with this configuration is effective in capturing the gel-like material that has flowed out of the pleated filter material 3, and in holding the captured gel-like material to prevent the gel-like material from flowing out again.

[0028] It is also preferable that the initial porosity of the rolled filter material 6 is 60% to 75%. It has been experimentally confirmed that by setting the initial porosity of the rolled filter material to this value, the effect of capturing and retaining the gel-like material that has flowed out from the pleated filter material 3 is maintained, and the effect of preventing the gel-like material from flowing out again is high.

[0029] The inner cylinder 7 is a cylindrical material with multiple openings 12, and allows the fluid to pass from its outer periphery to its inner periphery. It is mainly made of thermoplastic resin or metal, and prevents the rolled filter material 6 from deforming or the filter cartridge 1 from collapsing due to a pressure difference caused by clogging of the rolled filter material 6.

[0030] The end plates 8, 9 seal the upper and lower ends of the pleated filter material 3, net material 5, and wound filter material 6 of the filter cartridge 1 at both ends from the outer tube 2 to the inner tube 7. The end plates 8, 9 may be annular plates having an outer diameter substantially the same as the outer shape of the outer tube 2 and an inner diameter substantially the same as that of the inner tube 7, or, as shown in Figure 2, one of the end plates may be end plate 8 that seals the end of the filter cartridge 1 and the other may be end plate 9 having a seal structure that matches the shape of the container in which the filter cartridge 1 is attached.

[0031] The filter cartridge of the present invention can treat fluids such as pigment dispersions containing propylene glycol monomethyl ether acetate (PGMEA) or the like, ceramic capacitor slurries and electrode pastes containing binder solutions such as toluene and alcohol, and coating solutions containing methyl ethyl ketone or the like, and can capture solid matter contained in these fluids and gel-like foreign matter consisting of undissolved polymers and the like.

[0032] In the production of these fluids to be treated, pigments, dielectric materials, etc. may not be sufficiently dissolved or dispersed in organic solvents, and gel-like substances may be generated in such cases. For example, if gel-like substances appear on the coating surface during a coating process such as film molding, problems such as pinholes may occur in the molded film. EXAMPLES

[0033] (Method of measuring fiber diameter) The average fiber diameter of the nonwoven fabric used in the present invention was calculated by the following method. That is, multiple images of the nonwoven fabric were taken with an electron microscope, and 100 fibers were randomly extracted from the images to measure the fiber diameter. The measurement results were compiled into a histogram, and the fiber diameter was calculated from the histogram. Note that the fiber class values ​​used in creating the histogram were 0.5 μm or more and less than 1.5 μm, 1.5 μm or more and less than 2.5 μm, 2.5 μm or more and less than 3.5 μm, 3.5 μm or more and less than 4.5 μm, 4.5 μm or more and less than 5.5 μm, 5.5 μm or more and less than 6.5 μm, 6.5 μm or more and less than 7.5 μm, 7.5 μm or more and less than 8.5 μm, 8.5 μm or more and less than 9.5 μm, The average fiber diameter was calculated by summing the product of the class value and frequency for each class and dividing it by the total frequency for all classes. The average fiber diameter was calculated as follows: 9.5 μm or more and less than 10.5 μm, 10.5 μm or more and less than 11.5 μm, 11.5 μm or more and less than 12.5 μm, 12.5 μm or more and less than 13.5 μm, 13.5 μm or more and less than 14.5 μm, 14.5 μm or more and less than 15.5 μm, and 15.5 μm or more.

[0034] (Net material) The net material used was a PP mesh with a wire diameter of 176 μm, a density of 42 × 40 strands / inch, an opening rate of 51%, and a thickness of 320 μm.

[0035] (Rolled filter media) As the rolled filtering material, nonwoven fabrics a to i were prepared having the configurations shown in Table 1. The porosity of the nonwoven fabrics a to i was adjusted to 70% by adjusting the calendering conditions after laminating each layer.

[0036] [Table 1]

[0037] Average fiber diameter 0.5μm, basis weight 50g / m 2 PP melt-blown nonwoven fabric with an average fiber diameter of 30 μm and a basis weight of 15 g / m 2 After laminating and pleating the PP spunbond nonwoven fabric, a cylindrical pleated filter material was prepared by heat-sealing both ends. A number of common components were prepared by placing this pleated filter material between an outer cylinder with an opening rate of 80% and an inner cylinder with an opening rate of 40%.

[0038] (Prototype 1) The nonwoven fabric c in Table 1 was wound around the outer periphery of an inner cylinder with an opening rate of 60%, and the ends were spot-welded using a Branson LPX handheld ultrasonic welding machine manufactured by Emerson Japan. A net material was wound around the outer periphery, and the ends were similarly spot-welded. This was placed in the inner cylinder of the common component, and both the upper and lower ends were sealed with end plates to obtain the filter cartridge of prototype example 1. The filter cartridge of prototype example 1 had an outer diameter of 70 mm, an inner diameter of 32 mm, and a distance from one end of the end plate to the other end of 50 mm.

[0039] (Prototype Example 2) A filter cartridge of Prototype Example 1 was produced in the same manner as in Example 1, except that no net material was used. EXAMPLES

[0040] A glycerin aqueous solution was passed from the outer periphery side to the inner periphery side of the filter cartridge of Prototype Example 1 at a flow rate of 200 mL / min, and the initial pressure difference (initial differential pressure) between the outer periphery side (primary side) and the inner periphery side (secondary side) was measured. As a result, the differential pressure of the filter cartridge of Example 1 was 240 kPa.

[0041] Comparative Example 1 The initial differential pressure was measured by passing the glycerin aqueous solution from the outer periphery to the inner periphery of the filter cartridge of Prototype Example 2 at the same flow rate as in Example 1. As a result, the differential pressure of the filter cartridge of Comparative Example 1 was 250 kPa.

[0042] Next, 10 g of methylcellulose 400 manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. was dispersed in the glycerin aqueous solution as a gel-like substance per 1 L of the glycerin aqueous solution. The glycerin aqueous solution at this time was set to 70°C. It was then allowed to cool and adjusted to 21-27°C. At this time, no stirring such as dispersion was performed, and when the undissolved gel precipitated after cooling, it was stirred with a glass rod and a stirrer, and then ultrasonically dispersed to prepare the fluid to be treated. This was passed through at a constant flow rate of 200 mL / min, and the change in the pressure difference (differential pressure) between the primary side and the secondary side of each was observed. The results are shown in Table 2. The record for "0 minutes" is the differential pressure when the glycerin aqueous solution without the gel-like substance dispersed therein was passed through for 1 minute, and all units are in kPa.

[0043] [Table 2]

[0044] As is clear from Table 2, Comparative Example 1, which did not use a net material, had a high initial differential pressure, and the time until the differential pressure increased by 100 kPa from the initial pressure, which is the life of the filter cartridge, was shorter than that of Example 1. Furthermore, in the filter cartridge of Comparative Example 1, the gel-like material re-flowed out immediately after capture when the differential pressure reached 100 kPa from the initial differential pressure, whereas in Example 1, no re-flow of the gel-like material occurred.

[0045] (Prototype Examples 2-9) Using the nonwoven fabrics a, b, and d to i, filter cartridges were produced in the same manner as in Prototype Example 1. The configurations of each are shown in Table 3.

[0046] [Table 3]

[0047] (Examples 2 to 10) As in Example 1, a fluid to be treated was prepared by dispersing 10 g of methylcellulose 400 manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., as a gel-like substance in a glycerin aqueous solution per 1 L of the glycerin aqueous solution, and this was passed through the filter cartridges of prototypes 1 to 10 at a constant flow rate of 200 mL / min to observe the change in the differential pressure between the primary side and the secondary side of each. The results are shown in Table 4. The record for "0 minutes" is the differential pressure when a glycerin aqueous solution without a dispersed gel-like substance was passed through for 1 minute, and all units are kPa.

[0048] [Table 4]

[0049] Although the initial pressure difference was relatively high for the filter cartridges of Examples 2 and 6, no gelatinous matter flowed out to the secondary side until the end of the experiment, and it was found that the captured gelatinous matter was sufficiently trapped and rotten in the rolled filter material. In contrast, a small amount of gel was observed to flow out of the filter cartridges of Examples 5 and 9. However, both filter cartridges had low pressure difference and were considered to have good filter performance when no gelatinous matter was present.

[0050] (Examples 10 to 14) Nonwoven fabrics for rolled filter materials were created with the fiber structure of nonwoven fabric c and porosities of 50% (c-1), 60% (c-2), 75% (c-3), and 80% (c-4). Using these nonwoven fabrics c-1 to 4 and c, filter cartridges were manufactured in the same manner as in Prototype Example 1. The structures of each are shown in Table 5.

[0051] [Table 5]

[0052] Using the filter cartridges of prototypes 11 to 15, the initial differential pressure of each was measured in the same manner as in Example 1. In addition, a fluid to be treated in which a gel-like substance was dispersed was prepared in the same manner as in Example 2, and the outflow of the gel-like substance was observed when the differential pressure increased by 100 kPa from the initial differential pressure. The results are shown in Table 6.

[0053] [Table 6]

[0054] As the porosity decreased, the initial differential pressure increased, but no outflow of the gel-like material was observed even in Example 10, which had a porosity of 50%. In contrast, in Example 14, which used a wound filter material with a porosity of 80%, outflow of the gel-like material was observed when the differential pressure, which is the guideline for replacing the filter cartridge, increased by 100 kPa from the initial differential pressure. [Explanation of symbols]

[0055] 1 Filter Cartridge 2 Outer cylinder 3 Pleated filter media 4 Middle tube 5. Netting material 6 Roll Filter 7 Inner cylinder 8 End Plate 9 End Plate 10 aperture 11 Aperture 12 Aperture

Claims

1. A cylindrical filter cartridge that allows a fluid to flow from an outer periphery to an inner periphery, An outer cylinder disposed on the outermost periphery; A pleated filter material disposed on the inner peripheral side of the outer cylinder and formed in a pleated shape; An inner cylinder disposed on the inner circumferential side of the pleated filter material; A net material disposed on the inner circumferential side of the inner cylinder; A rolled filter material is disposed on the inner periphery side of the net material and is formed by rolling a nonwoven fabric; An innermost cylinder disposed on the inner periphery side of the rolled filter material; end plates that cover both ends of the outer tube and the innermost tube and are disposed above and below the outer tube and the innermost tube; A filter cartridge having

2. 2. The filter cartridge according to claim 1, wherein the rolled filter material is a laminated nonwoven fabric in which nonwoven fabrics having different average fiber diameters are laminated.

3. 3. The cartridge filter according to claim 2, wherein the laminated nonwoven fabric is a laminated nonwoven fabric in which a nonwoven fabric A having an average fiber diameter of 0.6 to 1.0 μm and a nonwoven fabric B having an average fiber diameter of 0.1 to 0.5 μm are laminated in the following order: nonwoven fabric A-nonwoven fabric B-nonwoven fabric A.

4. 2. The filter cartridge according to claim 1, wherein the wound filter material is a nonwoven fabric having a porosity of 60 to 75%.

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