Filter element for inclusion in filtration housing

Abstract

Provided is a filter element for inclusion in a filtration housing and for use as a chemical filter in chemical filtration, the filter element increasing the contact probability for adsorbing impurity foreign matter even at a liquid feed pressure equivalent to that of a conventional example, without heating or being heated by a liquid being filtered, and having excellent durability and further improved adsorption efficiency.　A filter element 1 for inclusion in a filtration housing is constituted by laminating a single set or a plurality of sets 2, 3, 4, … of impurity foreign matter adsorbing materials 2a, 3a, 4a, … arranged on a liquid feed side F1 and impurity foreign matter non-adsorbing materials 2b, 3b, 4b, … arranged on a discharge side F2, wherein, within each set 2, 3, 4, …, the liquid passing resistance of the liquid being filtered with respect to the impurity foreign matter non-adsorbing material 2b, 3b, 4b, … is higher than the liquid passing resistance of the same kind of liquid being filtered with respect to the impurity foreign matter adsorbing material 2a, 3a, 4a, ….

Description

Filter element for use within a filtration housing

[0001] This invention relates to a filter element used in a filter cartridge that allows a liquid to be filtered and purified to pass through, thereby filtering out impurities such as impure ions and impure fine particles.

[0002] To filter out impurities such as impurity ions and impurity particles that remain in liquids to be filtered, such as industrial chemicals, reagents, liquid raw materials, and their aqueous solutions, and adversely affect their quality and performance, various types of filters are used, such as mesh filters made of interwoven wires of metal or plastic, woven fabric filters made of synthetic fibers such as cotton, glass fiber, or fluororesin, nonwoven fabric filters made by mechanically, thermally, or chemically bonding nonwoven fibers, and permeable membrane filters. These filters are selected and used appropriately depending on the purpose of filtration, the type of liquid to be filtered, and the type and size of the impurities.

[0003] Such industrial filtration can generally be broadly classified into physical filtration, which physically captures and removes impurities, such as physical filters that capture and remove impurities, like nonwoven fabrics or membranes with varying mesh sizes, such as depth filters that coarsely filter impurities larger than about 10 μm, membrane filters that finely filter impurities of about 0.05 to 10 μm, ultrafiltration filters that ultrafilter impurities of about 1 nm to 0.05 μm, and dialysis membranes or reverse osmosis membrane filters that remove impurities smaller than 1 nm by dialysis or reverse osmosis; and chemical filtration, which captures and removes impurities mainly by adsorption through probabilistic means by contact with the fiber surface of a nonwoven fabric with adsorption capacity.

[0004] Chemical filters used in chemical filtration primarily remove impurities and foreign substances by adsorption, so increasing the contact probability is crucial. Lowering the flow rate of the liquid to be filtered per unit time increases the contact probability somewhat, but because the liquid is only supplied at low pressure, particle motion slows down, resulting in poor adsorption efficiency and thus poor removal efficiency. Furthermore, the amount of filtration does not increase significantly, leading to decreased productivity. On the other hand, increasing the thickness of the chemical filter increases the contact probability, but because it requires high pressure for liquid supply, the pressurization causes a temperature increase, leading to deterioration and a decline in quality. Alternatively, the chemical filter may not be able to withstand the high pressure, reducing its durability and requiring frequent replacement, thus also leading to decreased productivity. Or, even if the material to be filtered is heated to raise the liquid temperature and decrease viscosity, increasing the momentum of the molecules in the filtered material and impurities, the temperature increase will cause deterioration and lead to a decline in quality.

[0005] Patent Document 1 discloses a cartridge filter for liquid filtration comprising multiple filter media of a fiber diameter gradient type, in which multiple nonwoven fabrics having different functions are laminated and integrated and wound into a pleated or roll shape, wherein at least one of the multiple nonwoven fabrics is a graft polymerized nonwoven fabric having ion exchange groups due to graft polymerization, and the other is a non-graft polymerized nonwoven fabric having a smaller fiber diameter and average pore diameter than the graft polymerized nonwoven fabric. Patent Document 1 states that the cartridge filter for liquid filtration balances filtration performance and ion exchange capacity at a high level by combining a graft polymerized nonwoven fabric suitable for highly efficient ion capture and a non-graft polymerized nonwoven fabric with high particle capture efficiency, thus possessing a high degree of ability to remove both ions and fine particles and being highly reliable. The invention of Patent Document 1 does not solely aim to increase the contact probability of a chemical filter, i.e., ion capture.

[0006] Therefore, as a chemical filter used in chemical filtration, there was a need for a filter element for in-house filtration housing that would increase the probability of contact with impurities and thus further improve the adsorption efficiency, i.e., the removal efficiency, when removing impurities primarily by adsorption.

[0007] Japanese Patent Publication No. 2009-90259

[0008] The present invention was made to solve the aforementioned problems, and aims to provide a filter element for use as a chemical filter in chemical filtration that increases the contact probability for adsorbing impurities and foreign substances even at the same liquid flow pressure as conventional filters, without heating or being heated to the liquid to be filtered, and has excellent durability and further improved adsorption efficiency, for use within a filtration housing.

[0009] To achieve the above objective, a filter element for inclusion in a filtration housing is provided, comprising one or more sets of a material that adsorbs impurities and has voids for the liquid to be filtered, which is located on the liquid supply side of the liquid to be filtered and allows the liquid to pass through, and a material that does not adsorb impurities and has voids for the liquid to be filtered, which is located on the discharge side of the liquid to be filtered and allows the liquid to pass through, which are stacked together, characterized in that the resistance of the liquid to be filtered to pass through the material that does not adsorb impurities and for each set is higher than the resistance of the same type of liquid to pass through the material that adsorbs impurities and for the liquid to be filtered.

[0010] The filter element for this filtration housing has, for example, a liquid flow resistance of the liquid to be filtered through the impurity-non-adsorbing material of 0.2 to 300 kPa, and a liquid flow resistance of the liquid to be filtered through the impurity-adsorbing material of 0.1 to 100 kPa, preferably 0.1 to 10 kPa.

[0011] The filter element for this filtration housing is designed so that the liquid to be filtered has a viscosity of 0.2 to 10,000 mPa·s. The liquid to be filtered is preferably an aqueous solution.

[0012] The filter element for this filtration housing may, for example, have the following characteristics: the non-adsorbent material has a basis weight of 10 to 100 g / m, preferably 30 g / m, an average pore size of 50 to 1000 μm, preferably 900 μm, a porosity of 60 to 90%, preferably 90%, a fiber diameter of 10 to 50 μm, preferably 30 μm, and a thickness of 50 to 300 μm, preferably 210 μm; and the adsorbent material has a basis weight of 50 to 500 g / m, preferably 200 g / m, an average pore size of 5 to 100 μm, preferably 450 μm, a porosity of 60 to 95%, preferably 67%, a fiber diameter of 10 to 200 μm, preferably 45 μm, and a thickness of 50 to 2000 μm, preferably 800 μm.

[0013] The filter element for this filtration housing is made of an organic material comprising, for example, a thermoplastic resin selected from polyolefin resin, polyamide resin, polyester resin, polyacrylic resin, fluororesin, polyether resin, polycarbonate resin, sulfone resin, and imide resin, a thermosetting resin selected from polyurethane resin, epoxy resin, phenolic resin, silicone resin, and urea resin, a cellulose resin, a protein resin, and a polyglucosamine resin; an inorganic material comprising, for example, a silica material, an alumina material, a mineral material, and activated carbon; or a composite material made of the organic material and the inorganic material. The filter element for this filtration housing is made of, for example, a woven fabric, a nonwoven fabric, a porous membrane, paper, a mesh, a sintered body, a monolithic structure, or a particle packing.

[0014] The filter element for this filtration housing may be made of the material having ion-exchange functional groups and / or chelating groups, which is the impurity-adsorbing material.

[0015] The filter element for this filtration housing is more preferably such that the ion-exchange functional group is at least one cation exchange group selected from a sulfonic acid group, a carboxyl group, a phosphate group, and a hydroxyl group, and / or at least one anion exchange group selected from a primary ammonium group, a secondary ammonium group, a tertiary ammonium group, and a quaternary ammonium group, and the chelating group is at least one chelating group selected from an iminodiacetic acid group, a methylglucamine group, a cyano group, an aminophosphate group, an amidoxime group, a thiouronium group, a polyamine group, and a thiol group.

[0016] The filter element for this filtration housing is such that the impurity-adsorbing material is, for example, made of a radiation-graft polymerized resin into which the ion-exchange functional group is introduced, a graft copolymerized resin having the ion-exchange functional group in its side chain, or a block or random copolymerized resin having the ion-exchange functional group in the repeating unit of its main chain.

[0017] The filter element for this filtration housing may consist of the impurity-adsorbing material having the cation-exchange functional group, or it may have a first impurity-adsorbing material having the cation-exchange functional group and a second impurity-adsorbing material having the anion-exchange functional group in any order within the same set, or in any order within different sets.

[0018] The filter element for this filtration housing is characterized in that the non-adsorbent material for impurities and foreign matter is made of at least one of the following materials: polyolefin resin, polyamide resin, polyester resin, and sulfone-based resin.

[0019] For the filter element to be housed within this filtration housing, it is preferable that the non-adsorbent material for impurities is a spunbond nonwoven fabric.

[0020] In this filter element for use within the filtration housing, it is preferable that the impurity-adsorbing material and the impurity-non-adsorbing material in contact with it are joined under pressure. This joined material is joined under pressure, for example, by a touch roller, while being heated as needed.

[0021] The filter element for this filtration housing is, for example, a depth filter.

[0022] In this filter housing, the filter elements may be configured such that, among the multiple sets, the non-adsorbent material for impurities and foreign matter each has the same liquid flow resistance, and the adsorbent material for impurities and foreign matter each has the same liquid flow resistance.

[0023] In this filter housing, the filter elements may be arranged such that, in each of the multiple sets, the liquid flow resistance of at least the non-adsorbent material for impurities increases sequentially towards the discharge side.

[0024] The filter element for this filtration housing is cylindrical in shape with a lumen, and is sandwiched between an inner core having numerous openings that cover the inner surface of the lumen on the discharge side and an outer core having numerous openings that cover the outer surface of the fluid supply side and a single or multiple set of elements and the lumen together are sealed on the top of the cylindrical tube and sealed together on the bottom of the tube.

[0025] The filtration housing constructed to achieve the aforementioned objective is characterized in that it is housed in a filtration housing body consisting of a housing cover and a housing base, so as to allow the filtered liquid to pass through without leakage from the liquid supply side to the discharge side.

[0026] This filtration housing is such that the filtration housing body is connected to a discharge pipe on the discharge side and a liquid supply pipe on the liquid supply side.

[0027] The present invention relates to a filter element for use within a filtration housing, its filter cartridge, and the filtration housing containing it. When adsorbing and filtering impurities in the liquid to be filtered, the non-adsorbent nonwoven fabric with low liquid permeability resistance extends the time the liquid to be filtered remains. During this time, the probability of the impurities to be filtered diffusing within the impurity-adsorbing material and coming into contact with its fibers increases, thereby improving the adsorption performance, and thus the filtration performance.

[0028] This filter element for use within a filtration housing provides a predetermined resistance for the liquid to be filtered, such as an aqueous solution, to the non-adsorbent and non-adsorbent materials. This eliminates the need to significantly increase the liquid flow pressure, prevents heating of the liquid to be filtered, and thus avoids deterioration of the liquid's quality, resulting in superior productivity.

[0029] This filter element, designed for use within a filtration housing, is not only highly durable but can also be used stably for extended periods, contributing to cost reduction and resource conservation.

[0030] These are schematic cross-sectional views and partially enlarged schematic cross-sectional views showing a filter element for use within a filtration housing to which the present invention is applied, its filter cartridge, and the filtration housing containing it. This is a graph showing the difference in filtration performance between a filter element for use within a filtration housing to which the present invention is applied and an element to which the present invention is not applied.

[0031] The following describes in detail embodiments for carrying out the present invention, but the scope of the present invention is not limited to these embodiments.

[0032] The filter element 1 for use within a filtration housing of the present invention will be described with reference to Figure 1. It is for allowing the liquid to be filtered to pass through and for removing impurities, particularly ionic impurities, from the liquid to be filtered by adsorption. It consists of sets 2, 3, 4... of impurity-adsorbing materials 2a, 3a, 4a... and impurity-non-adsorbing materials 2b, 3b, 4b... stacked in single or multiple sets, preferably multiple sets. This filter element 1 is used, for example, as a filter cartridge 10, and is housed in a filtration housing body 103 consisting of a housing cover 101 and a housing base 102 to allow the liquid to be filtered to pass through without leakage.

[0033] In each of those sets 2, 3, 4..., the impurity and foreign matter adsorbing materials 2a, 3a, 4a... are located on the liquid delivery side F of the filtration housing body 103. １ In other words, the material is placed on the side where the liquid to be filtered enters, and the non-adsorbent material for impurities and foreign matter is placed on the discharge side F. ２ In other words, it is positioned on the side where the filtered liquid exits.

[0034] For each set 2, 3, 4..., the resistance of the liquid to be filtered, such as an aqueous solution, to the non-adsorbent material 2b, 3b, 4b... is higher than the resistance of the same liquid to be filtered, such as an aqueous solution, to the adsorbent material 2a, 3a, 4a.... As a result, when filtering the liquid to be filtered with this filter element 1, the non-adsorbent material 2b, 3b, 4b... with high liquid flow resistance causes the liquid to be filtered to remain within the adsorbent material 2a, 3a, 4a..., increasing the probability that the impurities to be filtered will diffuse within the adsorbent material 2a, 3a, 4a... and come into contact with its fibers, thus improving the adsorption efficiency, i.e., the removal efficiency, of the impurities.

[0035] The desired excellent adsorption efficiency is achieved when the fluid to be filtered, such as an aqueous solution, passes through each set 2, 3, 4... non-adsorbent material 2b, 3b, 4b... with a fluid flow resistance of 0.2 to 300 kPa, preferably 1 to 100 kPa, more preferably 1 to 50 kPa, and the fluid flow resistance of the fluid to be filtered, such as an aqueous solution, passes through each set 2, 3, 4... with the non-adsorbent material 2a, 3a, 4a... with a fluid flow resistance of 0.1 to 100 kPa, preferably 0.1 to 50 kPa, more preferably 0.1 to 10 kPa. This fluid flow resistance is achieved when the fluid to be filtered is, for example, a 0 to 100% by mass aqueous glycerin solution (viscosity 1 to 1400 mPa·s, preferably a 93% by mass aqueous glycerin solution (viscosity 320 mPa·s)) and the fluid passage area is 17.3 cm². ２ This value is obtained when the fluid flow rate is 60 mL / min. By using a filter element 1 for in-house filtration housing that is adjusted to have a flow resistance defined by the liquid to be filtered, such as an aqueous solution, particularly an aqueous glycerin solution of a specific concentration, the desired adsorption efficiency of impurities can be achieved even if the actual liquid to be filtered is various liquids such as aqueous solutions, suspensions, or colloidal solutions.

[0036] For each set 2, 3, 4..., if the resistance of the liquid to be filtered, such as an aqueous solution, to the non-adsorbent material 2b, 3b, 4b... is higher than the resistance of the same liquid to be filtered, such as an aqueous solution, to the adsorbent material 2a, 3a, 4a..., the difference is not particularly limited, but is preferably 5 kPa or more, more preferably 10 kPa or more. Within this range, the desired adsorption efficiency can be achieved for the actual liquid to be filtered.

[0037] The difference in liquid permeability resistance between these non-adsorbent materials 2b, 3b, 4b, etc. and non-adsorbent materials 2a, 3a, 4a, etc. can be adjusted according to the physical properties of each nonwoven fabric.

[0038] For example, (i) for the volume of each material, the porosity of the impurity non-adsorbing materials 2b, 3b, 4b... is set to 1 to 99%, preferably 40 to 95%, more preferably 60 to 90%, while the porosity of the impurity adsorbing materials 2a, 3a, 4a... is set to 1 to 99%, preferably 70 to 95%, more preferably 80 to 95%, and the difference between the two porosities is set to 1 to 50%, preferably 5 to 30%, more preferably 10 to 20%. Accordingly, an appropriate difference in liquid flow resistance may be generated between the two nonwoven fabrics 2a, 3a, 4a... and 2b, 3b, 4b... of each pair 2, 3, 4....

[0039] Or, (ii) the contact angle of air bubbles in ultrapure water measured with a submerged contact angle goniometer for the impurity non-adsorbing materials 2b, 3b, 4b... is set to 40 to 150°, preferably 80 to 150°, more preferably 100 to 130°, while the contact angle of air bubbles in ultrapure water for the impurity adsorbing materials 2a, 3a, 4a... is set to 80 to 180°, preferably 120 to 180°, more preferably 140 to 180°. Accordingly, an appropriate difference in liquid flow resistance may be generated between the two nonwoven fabrics 2a, 3a, 4a... and 2b, 3b, 4b... of each pair 2, 3, 4....

[0040] Or, (iii) a combination of at least two or more of (i) and (ii) above is adopted, so that the difference in appropriate liquid flow resistance between the two nonwoven fabrics 2a, 3a, 4a... and 2b, 3b, 4b... of each pair 2, 3, 4... can be adjusted.

[0041] If these differences between the two nonwoven fabrics 2a, 3a, 4a... and 22b, 3b, 4b... of each pair 2, 3, 4... are respectively smaller than the above ranges, the liquid to be filtered will not stay much in the impurity adsorbing materials 2a, 3a, 4a..., making it impossible to achieve the desired adsorption efficiency. On the other hand, if these differences are respectively larger than the above ranges, the permeability of the impurity non-adsorbing materials 2b, 3b, 4b... will become excessively low, leading to overpressure during filtration that may damage the filter element 1, or reduce the permeation amount and lower the adsorption efficiency.

[0042] The material of such impure foreign matter adsorbent materials 2a, 3a, 4a... is any of the following: an organic material consisting of at least one selected from the group consisting of: thermoplastic resins selected from polyolefin resins (specifically polypropylene resin, polyethylene resin, polymethylpentene resin, or polyketone resin), polyamide resins (specifically nylon 6, nylon 66), polyacrylonitrile resin, polystyrene resin, polyvinyl resins (specifically polyvinyl chloride resin, polyvinyl acetate resin, polyvinyl alcohol resin), polyester resins (specifically polyethylene terephthalate resin: PET resin, polybutylene terephthalate resin: PBT resin, polylactic acid resin), polyacrylic resin, fluororesins (specifically polytetrafluoroethylene resin: PTFE resin, perfluoroalkoxyalkane resin: PFA resin), polyether resins (specifically polyoxymethylene resin, polyethersulfone resin, polyetherketone resin), polycarbonate resin, sulfone-based resins (specifically polysulfone resin, polyphenylsulfone resin), and imide resins (specifically polyamideimide resin, polyetherimide resin); thermosetting resins selected from polyurethane resin, epoxy resin, phenol resin, silicone resin, and urea resin; cellulose-based resins (specifically cotton, rayon, cupra); protein-based resins (specifically wool, silk, collagen); and polyglucosamine-based resins (specifically chitosan); an inorganic material consisting of at least one selected from the group consisting of silica-based materials (specifically glass fibers, diatomaceous earth fibers), alumina-based materials, mineral-based materials (specifically perlite fibers, zeolite fibers, activated clay fibers), and activated carbon; or a composite composed of the organic material and the inorganic material. In this filter element for placement inside a filter housing, the impure foreign matter adsorbent material is, for example, woven fabric, non-woven fabric, porous membrane, paper, mesh, sintered body, monolith structure, or particle packing.

[0043] When the impurity-adsorbing materials 2a, 3a, 4a... remove impurity components such as sodium ions and calcium ions from the filtrate, the fibers of the impurity-adsorbing materials 2a, 3a, 4a... are made of a resin having ion-exchange functional groups in the repeating units (ion-exchange resin), and / or a resin having chelate groups. The impurity-adsorbing materials 2a, 3a, 4a... are, for example, those in which the ion-exchange functional group is at least one cation exchange group selected from a sulfonic acid group, a carboxyl group, a phosphoric acid group, and a hydroxyl group, and / or at least one anion exchange group selected from a primary ammonium group, a secondary ammonium group (specifically a methylammonium group), a tertiary ammonium group (specifically a dimethylammonium group), and a quaternary ammonium group (specifically a trimethylammonium group, a dimethylethanolammonium group), and the chelating group is at least one chelating group selected from an iminodiacetic acid group, a methylglucamine group, a cyano group, an aminophosphate group, an amidoxime group, a thiouronium group, a polyamine group, and a thiol group.

[0044] The impurity and foreign matter adsorbing materials 2a, 3a, 4a... may be any of the following: chemical bond nonwoven fabrics made by bonding these fibrous sheets with an adhesive; thermal bond nonwoven fabrics made by heating and partially melting these fibers to bond them; needle punch nonwoven fabrics made by needle punching these fibrous sheets to entangle the fibers; spunlace nonwoven fabrics made by entangling these fibers with a high-pressure water stream; stitch bond nonwoven fabrics made by sewing these fibrous sheets with thread; air-ray nonwoven fabrics made by blowing and accumulating these fibers with an air stream; melt-blown nonwoven fabrics made by melting resin and using high-temperature air sprayed from around a spinning nozzle to thin the fibers and accumulate them in a sheet; or spunbond nonwoven fabrics in which a web is directly formed during the spinning process.

[0045] The impurity and foreign matter adsorbing materials 2a, 3a, 4a... include, for example, nonwoven fabrics made of radiation-graft polymerized resin into which ion-exchange functional groups have been introduced. Such radiation-graft polymerized resins are obtained by liquid-phase graft polymerization, in which ion-exchange functional groups are introduced by irradiating fibers made of the aforementioned material with active radiation such as gamma rays or electron beams to activate the fiber surface and generate radicals on the main chain, and then reacting these radicals with graft monomers to generate graft monomer-derived side chains from the main chain. Alternatively, ion-exchange functional groups are introduced into graft monomer-derived side chains that do not have such ion-exchange functional groups.

[0046] Examples of graft monomers having such ion-exchange functional group ions include unsaturated monomers having vinyl groups. Specifically, examples of unsaturated monomers for directly introducing phosphate-modified groups into graft monomer-derived side chains by radiation graft polymerization include phosphate-containing vinyl monomers such as mono(2-methacryloyloxyethyl) acid phosphate, di(2-methacryloyloxyethyl) acid phosphate, mono(2-acryloyloxyethyl) acid phosphate, and di(2-acryloyloxyethyl) acid phosphate. Alternatively, examples of unsaturated monomers that can be used as precursors for introducing ion-exchange functional groups by radiation graft polymerization, forming graft monomer-derived side chains that do not have ion-exchange functional groups and into which ion-exchange functional groups can be introduced include glycidyl methacrylate, acrylonitrile, acrolein, chloromethylstyrene, and vinylbenzylglycidyl ether. For precursors to which ion-exchange functional groups can be introduced, such as glycidyl methacrylate or vinyl benzyl glycidyl ether, the glycidyl group of the precursor obtained by radiation graft polymerization can be reacted with a sulfonating agent, such as sodium sulfite, to introduce a sulfonic acid modified group; reacted with an amination agent, such as diethanolamine, to introduce an amino modified group; or reacted with a chelating agent, such as iminodiacetic acid, to introduce an iminodiacetic acid modified group. For acrylonitrile, acrolein, and chloromethylstyrene, ion-exchange functional groups can be introduced by reacting them with sulfonating agents, amination agents, or chelating agents.

[0047] The impurity and foreign matter adsorption materials 2a, 3a, 4a... may be made of radiation-graft polymerized resin, or nonwoven fabric made of graft copolymerized resin having ion-exchange functional groups in the side chains, or block or random copolymerized resin having ion-exchange functional groups in the repeating units of the main chain.

[0048] Resins having ion-exchangeable functional groups in their side chains include those in which unsaturated monomers are introduced into the side chains by chain transfer reactions, radical reactions such as irradiation of the main polymer with radiation, or ionic polymerization reactions of the main polymer. Resins having ion-exchangeable functional groups in the repeating units of the main chain include block or random copolymer resins, which are copolymerized with olefin monomers such as ethylene, amide monomers such as acrylamide, or polyvinyl alcohol raw material monomers such as vinyl acetate, and unsaturated monomers such as maleic acid, itaconic acid, fumaric acid, crotonic acid, acrylic acid, methacrylic acid, or vinyl sulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, or unsaturated ammonium monomers such as chloride-3-butenyltrimethylammonium.

[0049] These impurity-adsorbing materials 2a, 3a, 4a... each have a thickness of 0.05 to 5 mm, preferably 0.1 to 3 mm, and more preferably 0.1 to 1 mm, within each set 2, 3, 4... If the thickness is thinner than this range, even if the liquid to be filtered remains on the impurity-adsorbing materials 2a, 3a, 4a..., it will not be able to adsorb sufficiently, and the desired adsorption efficiency will not be achieved. On the other hand, if the thickness is thicker than this range, the liquid to be filtered will not be uniformly dispersed in the retention layer, and the desired adsorption efficiency will not be achieved.

[0050] In the filter element 1 for use within the filtration housing, it is preferable that multiple sets, for example 2 to 150 sets, of impurity-adsorbing materials 2a, 3a, 4a... and impurity-non-adsorbing materials 2b, 3b, 4b... are stacked, so that the impurity-adsorbing materials 2a, 3a, 4a... and impurity-non-adsorbing materials 2b, 3b, 4b... are stacked alternately.

[0051] The filter element 1 for use within the filtration housing may be a set of one or more sets of impurity-adsorbing materials 2a, 3a, 4a... and impurity-non-adsorbing materials 2b, 3b, 4b... in which the impurity-adsorbing materials 2a, 3a, 4a... are impurity-adsorbing materials having cation-exchange functional groups. Alternatively, the set of one or more sets of impurity-adsorbing materials 2a, 3a, 4a... and impurity-non-adsorbing materials 2b, 3b, 4b... may contain a first impurity-adsorbing material having cation-exchange functional groups and a second impurity-adsorbing material having anion-exchange functional groups, in any order within the same set, thereby enabling the adsorption and removal of anionic and cationic impurities, respectively. The filter element 1 for use within the filtration housing consists of multiple sets of materials 2a, 3a, 4a... that adsorb impurities and non-adsorbing materials 2b, 3b, 4b..., in which one set of materials is a first impurity-adsorbing material having cation exchange functional groups, and in another set of materials is a second impurity-adsorbing material having anion exchange functional groups. By having these different combinations alternately or together, it is possible to adsorb and remove both anionic and cationic impurities.

[0052] The filter element 1 for use within the filtration housing is characterized in that the non-adsorbent materials 2b, 3b, 4b... are made of at least one of the following materials: polyolefin resin (specifically polypropylene resin, polyethylene resin, polymethylpentene resin, polyketone resin), polyamide resin (specifically nylon 6, nylon 66), polyester resin (polyethylene terephthalate, polybutylene terephthalate, polylactic acid), and sulfone resin (polysulfone resin, polyphenylsulfone resin). The non-adsorbent materials 2b, 3b, 4b... have a higher resistance to the flow of the liquid to be filtered, such as an aqueous solution, than the adsorbent materials 2a, 3a, 4a..., but they do not have ion-exchange functional groups and are chemically low in activity, so they have almost no property to adsorb impurities. Therefore, they primarily cause the liquid to be filtered to remain in the adsorbent materials 2a, 3a, 4a..., and do not adsorb and remove impurities themselves.

[0053] If the non-adsorbent materials 2b, 3b, 4b, etc. are meltblown nonwoven fabrics or spunbond nonwoven fabrics, interfiber spaces are easily secured, allowing for the creation of liquid flow resistance without affecting the physical removal performance of impurities. Furthermore, because the fiber length is long and the overall structure is robust, it can be processed while maintaining sufficient strength even during the lamination process with impurity-adsorbing fibers. Moreover, since no binder components are used to bond the fibers together, clarity is high and the risk of contamination of the filtered liquid is reduced, which is preferable.

[0054] In the filter element 1 for use within the filtration housing, it is preferable that the impurity-adsorbing materials 2a, 3a, 4a... and the impurity-non-adsorbing materials 2b, 3b, 4b... within the same set that are in contact with it, or the impurity-non-adsorbing materials 2b, 3b, 4b... in the preceding and succeeding sets that directly overlap with it, are joined by applying pressure with a touch roller to press the nonwoven fabrics together, and by heating while pressing as needed, so that they do not peel off or separate when the liquid to be filtered is passed through under pressure.

[0055] The filter element 1 for use within the filtration housing is constructed by laminating one or more sets of materials that adsorb impurities and foreign matter 2a, 3a, 4a... and materials that do not adsorb impurities and foreign matter 2b, 3b, 4b..., and by having a total thickness of 5 to 40 mm, preferably 10 to 40 mm, and more preferably 15 to 40 mm, thereby improving the adsorption performance, i.e., the removal performance.

[0056] The filter element 1 for use within the filtration housing is preferably a depth (roll) filter because it can reliably capture impurities and foreign particles larger than a specific particle size in a liquid with a wide particle size distribution.

[0057] The filter element 1 for use within the filtration housing consists of multiple sets of materials 2a, 3a, 4a... that adsorb impurities and foreign matter and materials 2b, 3b, 4b... that do not adsorb impurities and foreign matter. If the non-adsorbent materials 2b, 3b, 4b... in each set have the same liquid flow resistance, and the impurities and foreign matter adsorbent materials 2a, 3a, 4a... in each set have the same liquid flow resistance, then there is no need to distinguish between the front and back of each set, resulting in a simple configuration.

[0058] The filter element 1 for use within the filtration housing consists of multiple sets of impurity-adsorbing materials 2a, 3a, 4a... and non-adsorbing materials 2b, 3b, 4b..., and in each of these sets, the liquid flow resistance of at least the non-adsorbing materials 2b, 3b, 4b..., preferably the liquid flow resistance of the non-adsorbing materials 2b, 3b, 4b... and the impurity-adsorbing materials 2a, 3a, 4a..., may increase sequentially towards the discharge side. This allows for coarse filtration of impurities from the supply side and more precise filtration of impurities towards the discharge side.

[0059] The filter element 1 for use within the filtration housing is cylindrical in shape with a lumen 5, and has an inner core 6 that covers the inner surface of the lumen on the discharge side and has a number of openings 6a, and a liquid supply side F １The filter cartridge 10 may be a cylindrical outer circumferential surface covered by an outer core 8 having numerous openings 8a, and the single or multiple sets and the lumen together are sealed with an upper end cap 7a on the cylindrical surface, and the single or multiple sets 2, 3, 4... together are sealed with a lower end cap 7b on the bottom. If it is a filter cartridge 10, when the filtration performance deteriorates, it is only necessary to replace it with a new filter cartridge 10, which improves work efficiency and productivity.

[0060] When filtering the liquid to be filtered, a filtration housing 100 is used, which houses a filter element 1 for internal use in the filtration housing. The filtration housing 100 has a cylindrical housing cover 101 whose upper part is closed and whose air vent opening 16 for air removal is normally closed, and a filtration housing body 103 which consists of a housing base 102 that abuts against the lower end of the cover to maintain liquid tightness, and the filter element 1 for internal use in the filtration housing is located inside the filtration housing body 103, on the liquid supply side F １ Discharge side F ２ It is housed in such a way that the liquid to be filtered is allowed to pass through without any leakage during the process. The filtration housing body 103 is located on the liquid supply side F １ The liquid supply pipe 12 and the discharge side F are located there. ２ It is connected to the discharge pipe 14 located there.

[0061] The lower end cap 7b has a hole corresponding to the lumen 5 and is fitted into the housing base 102, with a packing to ensure a liquid-tight seal. The housing base 102 has a hole in the center that connects to the lumen 5 of the filter element 1 for use within the filtration housing in a liquid-tight manner, and the lower end cap 7b is fitted into it, connecting to the discharge pipe 14. The housing base 102 has a liquid supply pipe 12 connected to its outer side. The outer diameter of the housing base is smaller than the inner diameter of the housing cover 101, so that the liquid to be filtered from the liquid supply pipe 12 reaches around the filter cartridge 10 and is forced to pass into the lumen 5 by pressure.

[0062] Although FIG. 1 shows an example in which impure foreign substances are removed by the liquid to be filtered flowing from the periphery of the filter element 1 for use in a filter housing toward the inner cavity 5, when impure foreign substances are removed by the liquid to be filtered flowing from the inner cavity 5 of the filter element 1 for use in a filter housing toward the periphery, the impure foreign substance-adsorbing materials 2a, 3a, 4a,... and the impure foreign substance-non-adsorbing materials 2b, 3b, 4b,... of the filter element 1 for use in a filter housing are arranged in reverse order for use.

[0063] The filter element 1 for use in a filter housing and the filter housing 100 using the same are used as follows. Liquid feeding side F １ injects the liquid to be filtered from the liquid feeding pipe 12 under pressure. The liquid to be filtered fills the housing cover 101 and passes through the filter element 1 for use in a filter housing of the filter cartridge 10 by pressure. At this time, since the flow resistance of the impure foreign substance-non-adsorbing materials 2b, 3b, 4b,... for each set 2, 3, 4,... is higher than that of the impure foreign substance-adsorbing materials 2a, 3a, 4a,..., this becomes the rate-determining step of the flow, so that the retention time of the liquid to be filtered in the impure foreign substance-adsorbing materials 2a, 3a, 4a,... is prolonged. During the retention time, impure foreign substances to be filtered diffuse in the impure foreign substance-adsorbing materials 2a, 3a, 4a,... and the probability of contact with the fibers thereof increases, whereby impure foreign substances are reliably adsorbed by the impure foreign substance-adsorbing materials 2a, 3a, 4a,..., and the adsorption performance, that is, the filtration performance is improved. The filtered liquid to be filtered reaches the inner cavity 5, and is discharged side F ２ is purified and taken out from the discharge pipe 14.

[0064] Hereinafter, examples to which the present invention is applied and comparative examples to which the present invention is not applied will be described in detail.

[0065] (Example 1) As materials 2a, 3a, 4a, etc. that adsorb impurities and foreign matter, cation exchange nonwoven fabrics (liquid flow resistance 0.6 kPa) made of modified polyethylene resin having ion exchange functional groups, with a basis weight of 200 g / m, average pore size of 450 μm, porosity of 67%, fiber diameter of 45 μm, and thickness of 800 μm were used, and as materials 2b, 3b, 4b, etc. that do not adsorb impurities and foreign matter, meltblown nonwoven fabrics (liquid flow resistance 13.1 kPa) were used. The liquid flow resistance was measured using an aqueous glycerin solution of approximately 93% by weight (viscosity 320 mPa·s) as the fluid, with one sheet of each nonwoven fabric punched out to a diameter of 47 mm and measured at a flow rate of 60 mL / min. These nonwoven fabrics were punched out to a diameter of 47 mm, and three of each were stacked alternately. They were then placed in a stainless steel filter holder KS-47 (product name of Advantec Toyo Co., Ltd.). A 10 ppm sodium chloride aqueous solution, which was the sample to be filtered, was passed through the filter holder at a rate of 35.6 mL / min, in the direction of passing through the material that adsorbs impurities and foreign matter, followed by the material that does not adsorb impurities, and so on. The sodium ion concentration of the filtrate was then measured. The results are shown in Figure 2.

[0066] (Comparative Example 1) A sample of the filter element was prepared in the same manner as in Example 1, except that a polypropylene resin net (liquid flow resistance 0.1 kPa) without ion-exchange functional groups was used, which had a lower liquid flow resistance than the cation-exchange nonwoven fabrics 2a, 3a, 4a, etc., which are non-adsorbent materials of impurities and foreign matter, as measured in the same manner as in Example 1. The sodium ion concentration of the filtrate was then measured. The results are shown in Figure 2.

[0067] (Comparative Example 2) Except that, in addition to using cation exchange nonwoven fabrics as the impurity-adsorbing nonwoven fabrics 2a, 3a, 4a... and meltblown nonwoven fabrics as the impurity-non-adsorbing materials 2b, 3b, 4b... in Example 1, only cation exchange nonwoven fabrics were used, a sample of the filter element was prepared in the same manner as in Example 1, and the sodium ion concentration of the filtrate was measured. The results are shown in Figure 2.

[0068] As is clear from Figure 2, in the sample of filter element 1 of Example 1 to which the present invention is applied, the sodium ion concentration in the filtrate decreased from 10 ppm to 0.60 ppm. However, in the sample of filter element of Comparative Example 1 to which the present invention is not applied, the retention of impurities in the impurities-adsorbing material was slower than in Example 1, due to the lower liquid flow resistance of the non-adsorbent material compared to the impurities-adsorbing material, resulting in a decrease in adsorption efficiency and a reduction to only 1.02 ppm in the filtrate. Furthermore, in the sample of filter element of Comparative Example 2 to which the present invention is not applied, although the adsorption capacity was somewhat improved because it consisted only of an impurities-adsorbing material, the adsorption efficiency was insufficient, and the reduction to only 0.81 ppm in the filtrate was insufficient.

[0069] (Example 2) A filter element used in a filtration housing as shown in Figure 1 was manufactured.

[0070] The resulting filtration housing 100 had superior adsorption performance for impurities and foreign substances, i.e., superior filtration performance compared to conventional housings.

[0071] The filter element for use within a filtration housing of the present invention, and the filtration housing containing it, are useful as filter media because they can efficiently and effectively adsorb and remove impurities, particularly ionic impurities.

[0072] 1 is the filter element for use inside the filtration housing, 2, 3, 4... are sets, 2a, 3a, 4a... are materials that adsorb impurities and foreign matter, 2b, 3b, 4b... are materials that do not adsorb impurities and foreign matter, 5 is the lumen, 6 is the inner core, 6a is the opening, 7a is the upper end cap, 7b is the lower end cap, 8 is the outer core, 8a is the opening, 10 is the filter cartridge, 12 is the liquid delivery pipe, 14 is the discharge pipe, 16 is the air vent opening for air release, 100 is the filtration housing, 101 is the housing cover, 102 is the housing base, 103 is the housing body, F １ F is the liquid delivery side. ２ This is the drainage side.

Claims

1. A filter element for a filtration housing, comprising one or more sets of a material that adsorbs impurities and foreign matter and has a gap through which the liquid to be filtered passes, and a material that does not adsorb impurities and foreign matter and has a gap through which the liquid to be filtered passes, stacked on the discharge side of the liquid to be filtered, characterized in that the resistance of the liquid to be filtered to the non-adsorbing material for each set is higher than the resistance of the same liquid to be filtered to the material that adsorbs impurities and foreign matter.

2. The filter element for inclusion in a filtration housing according to claim 1, characterized in that the liquid flow resistance of the liquid to be filtered against the impurity-non-adsorbing material is 0.2 to 300 kPa, and the liquid flow resistance of the liquid to be filtered against the impurity-adsorbing material is 0.1 to 100 kPa.

3. The filter element for inclusion in a filtration housing according to claim 1, characterized in that the liquid to be filtered has a viscosity of 0.2 to 10,000 mPa·s.

4. The filter element for inclusion in a filtration housing according to claim 1, characterized in that the non-adsorbent material for impurities has a basis weight of 10 to 100 g / m, an average pore size of 50 to 1000 μm, a porosity of 60 to 90%, a fiber diameter of 10 to 50 μm, and a thickness of 50 to 300 μm, and the adsorbent material for impurities has a basis weight of 50 to 500 g / m, an average pore size of 5 to 100 μm, a porosity of 60 to 95%, a fiber diameter of 10 to 200 μm, and a thickness of 50 to 2000 μm.

5. The filter element for inclusion in a filtration housing according to claim 1, characterized in that the impurity foreign matter adsorbing material is made of an organic material comprising at least one of the following: a thermoplastic resin selected from polyolefin resin, polyamide resin, polyacrylonitrile resin, polystyrene resin, polyvinyl resin, polyester resin, polyacrylic resin, fluororesin, polyether resin, polycarbonate resin, sulfone resin, and imide resin; a thermosetting resin selected from polyurethane resin, epoxy resin, phenolic resin, silicone resin, and urea resin; a cellulose resin; a protein resin; and a polyglucosamine resin; or an inorganic material comprising at least one of the following: silica, alumina, mineral, and activated carbon; or a composite of the organic material and the inorganic material.

6. The filter element for inclusion in a filtration housing according to claim 5, characterized in that the impurity-adsorbing material is made of the material having ion-exchange functional groups and / or chelating groups.

7. The filter element for inclusion in a filtration housing according to claim 6, characterized in that the ion-exchange functional group is at least one cation exchange group selected from a sulfonic acid group, a carboxyl group, a phosphate group, and a hydroxyl group, and / or at least one anion exchange group selected from a primary ammonium group, a secondary ammonium group (specifically a methylammonium group), a tertiary ammonium group (specifically a dimethylammonium group), and a quaternary ammonium group (specifically a trimethylammonium group, a dimethylethanolammonium group), and the chelating group is an iminodiacetate group, a methylglucamine group, a cyano group, an aminophosphate group, an amidoxime group, a thiouronium group, a polyamine group, and a thiol group.

8. The filter element for inclusion in a filtration housing according to claim 1, characterized in that the impurity-adsorbing material is made of a radiation-graft polymerized resin into which the ion-exchange functional group is introduced, a graft copolymerized resin having the ion-exchange functional group in its side chain, or a block or random copolymerized resin having the ion-exchange functional group in the repeating unit of its main chain.

9. The filter element for inclusion in a filtration housing according to claim 7, characterized in that the impurity-adsorbing material having the cation-exchange functional group consists of the impurity-adsorbing material having the cation-exchange functional group, or has a first impurity-adsorbing material having the cation-exchange functional group and a second impurity-adsorbing material having the anion-exchange functional group in any order within the same set, or in any order within different sets.

10. The filter element for inclusion in a filtration housing according to claim 1, characterized in that the non-adsorbent material for impurities is made of at least one of the materials selected from polyolefin resin, polyamide resin, polyester resin, and sulfone resin.

11. The filter element for inclusion in a filtration housing according to claim 1, characterized in that the impurity-free material is a spunbond nonwoven fabric.

12. The filter element for inclusion in a filtration housing according to claim 1, characterized in that the impurity-adsorbing material and the impurity-non-adsorbing material in contact therewith are a pressure-bonded body.

13. A filter element for inclusion in a filtration housing according to claim 1, characterized in that it is a depth filter.

14. The filter element for inclusion in a filtration housing according to claim 1, characterized in that, among the multiple sets, the non-adsorbent material for impurities and foreign matter each has the same liquid flow resistance, and the adsorbent material for impurities and foreign matter each has the same liquid flow resistance.

15. The filter element for inclusion in a filtration housing according to claim 1, characterized in that, in each of the multiple sets, the liquid flow resistance of at least the non-adsorbent material for impurities increases towards the discharge side.

16. The filter element for inclusion in a filtration housing according to claim 1, characterized in that it is a filter cartridge having a cylindrical shape with a lumen, sandwiched between an inner core having numerous openings that cover the inner surface of the lumen on the discharge side and an outer core having numerous openings that cover the outer surface of the fluid supply side, and the single or multiple sets and the lumen are sealed together on the cylindrical surface and the single or multiple sets are sealed together at the bottom of the cylinder.

17. A filtration housing characterized in that a filter element for internal use in any of claims 1 to 16 is housed in a filtration housing body consisting of a housing cover and a housing base such that the filtered liquid is allowed to pass through without leakage between the liquid supply side and the discharge side.

18. A filtration housing characterized in that the filtration housing body is connected to a discharge pipe on the discharge side and a liquid supply pipe on the liquid supply side.

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