JP2019130493A - Hollow fiber membrane module - Google Patents

Abstract

To provide a hollow fiber membrane module that has strong detachment strength of a potting part.SOLUTION: A hollow fiber membrane module includes: a resin case 1; and a plurality of hollow fiber membrane bundles 4 filled in the resin case 1. The resin case 1 is constituted by connecting a first member 2 to a second member 3 which are respectively made of different resin materials. The first member 2 has a fabric member 6 for closing a plurality of openings. The fabric member 6 is fixed to the resin material of the first member 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hollow fiber membrane module mainly used in a water purifier for filtering tap water.

  In recent years, hollow fiber membrane modules are frequently used in microfiltration, ultrafiltration and the like for filtering tap water and wastewater. In the hollow fiber membrane module, the hollow fiber membranes are converged and fixed by a potting material at both ends or one end of the case, and the potting part is fixed to the case covering the outside. The raw water side and the filtered water side are blocked by the potting portion so that the raw water to be filtered passes through the hollow fiber membrane and is discharged as filtered water.

  However, when this hollow fiber membrane module is used in a water purifier that purifies tap water, the potting part is momentarily subjected to high pressure due to fluctuations in the water pressure due to opening and closing of the faucet, and this water pressure fluctuation is repeated. Separation of the part and the case may occur. In particular, when the adhesive property between the potting material and the case is weak, there is a problem that cracks are likely to occur between the potting portion and the case, and the raw water leaks due to peeling.

  In addition, in order to suppress this peeling, there are methods of applying a primer to the inner surface potting part of the case and plasma processing to improve the adhesion of the resin surface of the case. Take it.

  On the other hand, Patent Document 1 proposes a hollow fiber membrane module and a method for manufacturing the same that are less likely to cause problems such as leakage to the filtrate side of raw water by smoothing the sealing surface of the potting part and the case. .

Japanese Patent Application Laid-Open No. 2015-142886

  However, in order to smooth the potting part and the sealing surface of the case as in Patent Document 1, additional processing such as buffing is necessary, and if the processing is insufficient, the effect of fixing the potting part is low. For this reason, it is necessary to select a resin material that can be processed or to obtain an optimal case shape. Therefore, there is a problem that selection of the case material is further limited.

  An object of this invention is to provide the hollow fiber membrane module with the strong peeling strength of a potting part and selection of a case material not limited in view of the above problems.

The hollow fiber membrane module of the present invention that solves the above problems is a hollow fiber membrane module comprising a resin case and a plurality of hollow fiber membrane bundles filled in the resin case,
The resin case is configured by connecting a first member having a plurality of openings formed on the outer peripheral surface and a second member having a potting material on the inside which fixes one end of the hollow fiber membrane bundle,
The resin material of the first member and the resin material of the second member are different types of resins.

  In a preferred embodiment of the hollow fiber membrane module of the present invention, the first member has a cloth-like member that closes the plurality of openings.

  Moreover, as for the hollow fiber membrane module of the preferable form of this invention, the said cloth-like member is being fixed to the resin material of the said 1st member.

  In the hollow fiber membrane module according to a preferred embodiment of the present invention, the opening of the opening of the first member is 60 to 250 μm.

  The hollow fiber membrane module of the present invention uses a resin material having good adhesiveness different from the resin material of the first member for the second member, so that the pressure resistance of the potting portion is higher than the resin case made of a single resin material. Improve and prevent water leakage. By forming a plurality of openings on the outer peripheral surface of the resin case, it is possible to secure a large flow path of the raw water to be filtered, but a highly fluid resin is selected for the first member different from the resin material of the second member This makes it easier to form the first member into a plurality of openings.

  In the case of a structure in which the first member and the second member are integrated, a complicated mold structure can be obtained. By dividing the structure into two members, a mold structure that can be easily molded can be obtained, and the first member and the second member are connected. Therefore, the dimensional accuracy of each member can be increased.

  When developing a plurality of hollow fiber membrane modules, the cost of mold production can be reduced by making either the first member or the second member a common member, which makes it easier to deploy to other types.

It is a schematic sectional drawing of the hollow fiber membrane module which concerns on one example of embodiment of this invention. It is another schematic sectional drawing of the hollow fiber membrane module which concerns on one Embodiment 2 of this invention. It is a schematic sectional drawing of the hollow fiber membrane module which concerns on the example 3 of one embodiment of this invention. It is a schematic perspective view of the 1st member concerning other example embodiments of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the embodiments. In the present application, the terms relating to the position and direction such as up and down are hollow fiber membrane modules 10 arranged in the orientation shown in FIG. 1 (that is, the end 4a of the hollow fiber membrane bundle is opened downward in the vertical direction. However, the hollow fiber membrane module of the present invention is not necessarily used only in the direction of FIG. .

  FIG. 1 is a schematic cross-sectional view of a hollow fiber membrane module according to an embodiment of the present invention. In FIG. 1, a hollow fiber membrane module 10 is a resin case having a first member 2 which is a resin case having a plurality of openings formed on the outer peripheral surface, and a potting material 5 to which one end of a hollow fiber membrane bundle 4 is fixed. A second member 3, a hollow fiber membrane bundle 4 and a potting material 5 are included. The hollow fiber membrane bundle 4 is housed in the first member 2 and the second member 3 in a U-shaped state, and the end 4a of the hollow fiber membrane bundle 4 is sealed to the second member 3 by the potting material 5. It is fixed. The open state of the hollow fiber membrane bundle 4 is formed by simultaneously cutting the end portion 4a of the hollow fiber membrane bundle and the potting material 5 which is sealed and fixed. Since the opening is formed on the outer peripheral surface of the module, water can easily flow into the hollow fiber membrane accommodated in the resin case 1, and the membrane area can be used more effectively.

  As the material for the hollow fiber membrane, hydrophilic polysulfone or the like is preferably used. Polysulfone is excellent in biological properties, heat resistance, chemical resistance and the like, and is preferable for water purifier applications. In addition, various materials can be used, and polyacrylonitrile, polyfinylene sulfone, polyether sulfone, polyethylene, polypropylene, polypropylene, and cellulose acetate are often used. The hollow fiber membrane preferably has an outer diameter of 300 to 500 μm, an inner diameter of 200 to 340 μm, and a film thickness of 50 to 100 μm in order to maintain the strength against water pressure. A bundle of hollow fiber membranes made of different materials may be used. If a hollow fiber membrane made of hydrophobic polyethylene or polypropylene is placed in a hydrophilic hollow fiber membrane bundle, air mixed in water can be discharged.

  The potting material 5 is improved in safety by using a polyurethane resin. The potting material only needs to be able to seal between the case and the hollow fiber membrane bundle 4 and between the hollow fiber membranes, and a two-component mixed type epoxy resin in which a fluid main agent and a curing agent are mixed and reacted and cured is easy to handle. ,preferable.

  The 1st member 2 and the 2nd member 3 are cylindrical shapes, and are connected up and down. The first member 2 and the second member 3 are fitted by the protrusions of the fitting portions 9 to form one case. The second member 3 is fitted so as to cover the first member 2.

  Here, the resin material of the first member 2 and the resin material of the second member 3 are different types of resins. By forming a plurality of openings 7 on the outer peripheral surface of the resin case 1 filled with the hollow fiber membrane, a large flow path of the raw water to be filtered can be secured, and the membrane area can be made more effective by facilitating the inflow of the raw water. However, by selecting a highly fluid resin different from the resin material of the second member 3 for the first member 2, a plurality of openings can be easily formed in the first member 2.

  Further, by using a resin material having a high adhesive strength with the potting material, which is different from the resin material of the first member 2, for the second member 3, the pressure resistance of the potting portion is higher than that of a resin case made of a single resin material. Can be improved and water leakage can be prevented.

  The resin material of the first member is different from that of the second member even when the first member is different from the raw material monomer such as a combination of polypropylene and ABS (acrylonitrile / butadiene / styrene copolymer) resin. Although it is a combination of the same monomers, those having different polymerization degrees, different copolymerization ratios, different monomer sequences (random copolymers, block copolymers, graft copolymers, etc.) Different additives may be used. In the present application, when the first member and the second member are manufactured by injection molding, different resin materials are used with different melting points, softening points, or melt flow rates. Here, the method for measuring the melt flow rate conforms to JIS K 7210-1: 2014 (ISO 1133-1: 2011). The difference in the resin material means that the difference between the melting point and the softening point is 5 ° C. or more, or the melt flow rate is at least 5 g / 10 minutes or more. The material of the first member is generally a resin such as PP (polypropylene), ABS (acrylonitrile / butadiene / styrene copolymer), PC (polycarbonate), AS (acrylonitrile / styrene copolymer), PS (polystyrene). Used. By selecting a material that has good adhesion to the cloth-like member or a material that can be easily fixed as the first member, the peel strength can be improved.

  The material of the second member 3 is generally a resin such as ABS, PC, AS, or PS, but a material having high adhesive strength with the potting material is selected.

  When the transparent material is selected for both the first member 2 and the second member 3, it is preferable because the hollow fiber membrane can be inspected even after the assembly process.

  In addition, when the cloth-like member 6 is integrally formed or when a minute opening is formed, it is preferable to select a material having high fluidity. The material having high fluidity preferably has a melt flow rate of 5 g / 10 min or more, and more preferably 7.5 g / 10 min or more.

  When the first member 2 and the second member 3 are formed as one member, it is possible to form the resin case 1 as an integral member and to mold the bonding surface with the potting material 5 and other portions with different resin materials. Since the mold structure is complicated, the mold structure can be easily formed by dividing into two members, and the dimensional accuracy of each member for connecting the first member 2 and the second member 3 can be increased.

  Rather than using a seal member such as an O-ring at the fitting portion between the first member 2 and the second member 3 to prevent water leakage, the first member 2 and the second member 3 have annular protrusions, notches, and claws. The number of members can be reduced if it is a method of fitting by attaching. Rather than using ultrasonic welding, bonding with adhesives, screwing, etc., as a case, the mating structure eliminates the need for ultrasonic welding equipment and seal members, and makes assembly easier. Cost can be reduced. In any case, the first member 2 and the second member 3 are configured not to be detached. In order to reduce molding defects such as sink marks, it is preferable that the first member 2 and the second member 3 have a constant thickness.

  The first member 2 has a plurality of openings 7, but the cloth-like member 6 may be fixed so as to cover the openings 7. When the raw water containing a lot of particulate matter is filtered by having a cloth-like member covering the opening 7, a part of the raw water is removed by the cloth-like member 6 and then flowed into the hollow fiber membrane. Can be extended. Furthermore, since the cloth-like member 6 is provided on the outer side of the hollow fiber membrane module 10, that is, on the outer peripheral side of the resin case 1, it can be filled with granular or powdered filter media, and is suitable as a component of a water purifier or other filtration device. Can be used. Moreover, in order to reduce the pressure loss at the time of water flow, the opening of the cloth-like member 6 is preferably as large as the strength allows. Here, the term “mesh” may be used to measure the vertical and horizontal lengths of a fiber-free space with an optical microscope, magnifier, etc., or using standard particles with a known diameter, etc., and its rejection rate (removal rate). You may ask for.

  In order to obtain a long-life hollow fiber membrane module, it is preferable that the hole diameter of the hollow fiber membrane is smaller than the opening of the cloth-like member 6. The pore diameter of the hollow fiber membrane is preferably 10 μm or less for capturing turbid substances in water, 5 μm or less for capturing cysts such as Cryptosporidium, and 0.3 μm or less for capturing bacteria. In this case, the pore diameter may be measured by subjecting a scanning photomicrograph to image processing, and a method for obtaining the standard particle having a known diameter is preferably used because the measurement accuracy is good. .

  As a fixing method for fixing the cloth-like member 6 to the first member 2, the first member 2 and the first member 2 may be integrally formed by insert molding, or may be attached by an adhesive, heat-sealed, ultrasonic welding, or pressure bonding. There is a way to fix. In insert molding, the process of fixing the cloth-like member 6 and the first member 2 becomes unnecessary, and the cost can be reduced. Further, by providing a convex portion on the first member 2 or raising a rib, a structure in which a cloth-like member is sandwiched between an outer peripheral surface and an inner peripheral surface with a resin can be obtained, and the cloth-like member 6 is peeled off. Strength can be improved.

  As the cloth-like member 6, a woven fabric, a knitted fabric, or a non-woven fabric is often used in order to allow only water to pass through. For woven fabrics and knitted fabrics, there are metals such as stainless steel and materials such as nylon, polyester, carbon, polytetrafluoroethylene, polypropylene, and polyethylene, but this does not apply if the material has the function of allowing water to be treated to pass through. . The nonwoven fabric is made of synthetic resin such as polyester, polypropylene, polyethylene, or nylon. Similarly, in order to reduce the flow resistance of the raw water to be filtered, it is preferable that the opening 7 is large as long as the strength of the first member 2 allows.

  When developing a plurality of hollow fiber membrane modules, by using either the first member 2 or the second member 3 as a common member, it is possible to reduce the cost of mold production and to easily deploy to other varieties.

  The operation and action of the hollow fiber membrane module configured as described above will be described below. The flow of water to be filtered, such as tap water, passes through a plurality of openings 7 on the outer periphery of the first member 2, passes through holes on the outer periphery of each single hollow fiber membrane, penetrates into the inside, and hollow fibers It can be taken out as purified water from the end of the hollow fiber membrane bundle 4 through the inner tube of the membrane.

  FIG. 2 shows a configuration in which the first member 2 is fitted so as to cover the second member 3 as another embodiment of the present invention. Similarly, since the resin material of the first member 2 and the resin material of the second member 3 are different, the same effect as in FIG. 1 can be expected. Considering the strength and formability of each member, or the strength of the connecting portion between the first member and the second member, any mode may be adopted according to the shape of the cartridge.

  FIG. 3 shows a configuration in which the first member 2 is fitted to cover the second member 3 as another embodiment of the present invention. Since the shape of the second member 3 is simple, a reduction in mold cost can be expected when the second member 3 is to be changed depending on the type.

  FIG. 4 shows a schematic perspective view of an embodiment of the first member 2 according to the present invention as viewed from above. By selecting a highly fluid resin, a plurality of openings 7 can be formed on the outer periphery. The opening of the opening 7 can be arbitrarily set, but the cloth-like member 6 may not be used if the opening is smaller than the target substance to be blocked or removed. In this case, since the cloth-like member is not used, the cost is reduced, and the cloth-like member can be prevented from being peeled off or torn. When the opening is formed, the opening is preferably 60 to 250 μm from the viewpoint of moldability and pressure loss during water passage. For the opening of the opening, the length in the vertical direction and the horizontal direction of the opening is measured with a magnifying glass or the like, and the average value may be used as an index. The shape of the opening may be a circle or other polygonal shape, but a rectangle is preferred for ease of molding.

  The present invention can be suitably used for water treatment filtration and hollow fiber membrane modules in addition to water purifiers in general, such as faucet direct connection type, stationary type, pot type, and undersink type, but is limited to these including other filter applications. It is not something.

DESCRIPTION OF SYMBOLS 1 Resin case 2 1st member 3 2nd member 4 End part 5 of hollow fiber membrane bundle 4a Hollow fiber membrane bundle Potting material 6 Cloth-like member 7 Opening 8 Potting part 9 Fitting part 10 Hollow fiber membrane module

Claims (4)

A hollow fiber membrane module comprising a resin case and a plurality of hollow fiber membrane bundles filled in the resin case,
The resin case is configured by connecting a first member having a plurality of openings formed on the outer peripheral surface and a second member having a potting material on the inside which fixes one end of the hollow fiber membrane bundle,
A hollow fiber membrane module in which the resin material of the first member and the resin material of the second member are different types of resins.   The hollow fiber membrane module according to claim 1, wherein the first member has a cloth-like member that closes the plurality of openings.   The hollow fiber membrane module according to claim 2, wherein the cloth-like member is fixed to a resin material of the first member.   The hollow fiber membrane module according to claim 1, wherein the opening of the first member is 60 to 250 μm.

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