Filter cartridge for liquid filtration systems

Abstract

A filter element (1) for a liquid filtration system includes a filter element housing (2) and a plurality of hollow fibers (3) arranged within the filter element housing (2), which form a hollow fiber membrane filter. At least one end of the hollow fibers (6, 10) passes through an opening (7) within the filter element housing (2). The filter element housing (2) includes at least one housing wall segment (11) made of a porous material, thereby providing a liquid-conducting connection between the exterior of the filter element housing (2) and the outer surface of the hollow fibers (3) within the filter element housing (2). The porous material of the housing wall segment (11) may include an adsorbent material. The porous material of the housing wall segment (11) may also include a dimensionally stable sintered element made of metal, ceramic, or plastic.

Description

Technical Field

[0001] The present invention relates to a filter element for a liquid filtration system, the filter element having a filter element housing and a plurality of hollow fibers arranged within the filter element housing, the hollow fibers forming a hollow fiber membrane filter, wherein at least one open end of the hollow fiber passes through an opening within the filter element housing. Background Technology

[0002] Various filter cartridges exist for use in filtration devices to filter liquids flowing through them. Typically, a filter cartridge includes at least one filter medium encapsulated within a cartridge housing. Liquid flows into the cartridge housing and comes into contact with the filter medium, thereby producing a filtration effect, such as removing unwanted particles or substances from the liquid, or altering the properties of the liquid based on the filtration effect resulting from the contact between the liquid and the filter medium.

[0003] To control liquid flow and filtration efficiency, many filter cartridge housings include a liquid inlet and an outlet. The filter cartridge design provides a liquid flow path from the inlet to the outlet, creating a flow path through the filter cartridge housing and the filter media contained within it. The filter media can be a free-flowing material comprising numerous fine particles that must be retained within the filter cartridge. The filter media can also comprise hollow fibers, through which the liquid must pass to produce a filtration effect. Typically, these hollow fibers are relatively fragile and must be protected by the filter cartridge housing. Therefore, the filter cartridge housing provides a dimensionally stable enclosure to retain the filter media within the filter cartridge and provides mechanical stability, thus protecting the filter media within the housing. Furthermore, most filter cartridges are designed for removable installation within the filtration unit, requiring the filter cartridge housing to allow for the pushing and pulling of the filter cartridge during installation or removal. Therefore, most filter cartridge housings are made of suitable polymer materials that are easy to manufacture, inexpensive, provide sufficient mechanical stability to prevent any liquid from leaking out of the housing, and are chemically inert to the liquid that the filter cartridge is filtering.

[0004] The opening of the filter cartridge housing must be covered with a cap that allows fluid to pass through but retains the filter media inside the housing. For most filter cartridges, this cap is installed on the inside or outside of the housing and is made of, for example, a woven or non-woven flexible fiber material with a pore size or mesh size small enough to keep the filter media inside the housing.

[0005] If the filter material is hollow fiber, at least one end of the hollow fiber passes through an opening in the filter cartridge housing. All gaps between the hollow fibers are liquid-tightly sealed by means of an adhesive, which secures and ensures that the open end of the hollow fiber passes through the opening. Liquid flowing through the filter cartridge is forced through the corresponding hollow fiber walls, thus producing the desired filtration effect. However, if the liquid contains large particles before passing through the hollow fiber walls, these particles can easily clog the hollow fiber walls, reducing the filter cartridge's filtration efficiency. Therefore, most filter cartridges using hollow fiber as the filter medium also include a pre-filter, which is placed along the liquid flow path before the hollow fiber membrane filter.

[0006] In one embodiment described in WO2001 / 007151A2, a pre-filter is installed inside a filter cartridge housing that encapsulates hollow fibers to prevent unnecessary clogging of the hollow fiber devices within the core area of ​​the tubular filter cartridge.

[0007] WO2006 / 021966 describes a filter cartridge installed in the cup-shaped portion of a bottle. A hollow fiber membrane filter is disposed within a filter body made of an inert polymer. The hollow fiber membrane filter is encased in a tubular activated carbon block, which is positioned between the hollow fiber membrane filter and the surrounding filter cartridge housing.

[0008] US Patent 2009 / 159521A1 discloses a filter element having a rod-shaped hollow fiber membrane filter installed within a hollow cylindrical filter element housing, the cylindrical outer surface of which has an opening. A porous shell serving as a pre-filter is disposed between the rod-shaped hollow fiber membrane filter and the cylindrical outer surface of the filter element housing.

[0009] However, installing these additional filter elements onto the filter cartridge housing, making them pre-filters for the hollow fiber membrane filter, requires additional steps in the filter cartridge manufacturing process. Furthermore, most installation methods require the use of fasteners, or at least leaving some space around the opening to allow for the installation of the additional filter elements, ensuring the opening is completely covered by them.

[0010] Therefore, there is a need for a filter housing that is easy to manufacture, and where there is not much space next to the opening in the filter housing for additional filter elements. Summary of the Invention

[0011] This invention relates to a filter cartridge as described above, wherein the cartridge housing includes at least one housing wall segment made of a porous material, which provides a liquid-conducting connection between the exterior of the cartridge housing and the outer surface of hollow fibers inside the cartridge housing. Preferably, this housing wall segment provides a unique liquid-conducting connection between the exterior of the cartridge housing and the outer surface of hollow fibers inside the cartridge housing. The porous material according to the invention differs from any material that is impermeable to liquids but, after the housing wall segment is manufactured, has one or more holes machined through it to allow liquid to pass through. In contrast, the housing wall segment is made of a liquid-permeable porous material without any subsequent processing, particularly without machining holes or openings within the porous material. This simplifies the manufacture of the cartridge housing. Furthermore, since the porous material can be used to make the cartridge housing, wherein at least one outer wall portion is made of the porous material, the cartridge housing does not require, or requires little, space next to the opening within the cartridge housing for placing additional filter elements, which would allow for the installation of additional filter elements such that the opening is tightly covered by the additional filter elements.

[0012] The filter housing does not require any other openings to provide liquid conduction between the outside of the filter housing and the outer surface of the hollow fibers inside the filter housing, such as holes in a polymer housing, which are covered by the filter element mounted next to such an opening.

[0013] Porous materials act as filters for liquids flowing through them. This filtration can be purely mechanical, achieved by trapping particles larger than a specific size of the porous material in the fluid. Alternatively, porous materials can include chemically active components, such as adsorbents, to remove unwanted components from the liquid.

[0014] Preferably, the inner wall surface of the housing wall segment made of porous material is flush with the adjacent wall area of ​​the filter element housing (if there is a wall area of ​​an adjacent housing wall segment with the same orientation as the housing wall segment). Similarly, preferably, the outer wall surface of the housing wall segment made of porous material is also flush with the adjacent wall area of ​​the filter element housing (if there is a wall area of ​​an adjacent housing wall segment with the same orientation as the housing wall segment). Therefore, the housing wall segment made of porous material, as part of the filter element housing, does not occupy more space than a conventional filter element housing.

[0015] The shell wall section, made of porous material, provides openings in the filter cartridge housing and establishes a liquid-conducting connection with the outer surface of the hollow fibers. However, due to the porous nature of the material, the shell wall section acts as a pre-filter in the hollow fiber membrane filter. When the raw liquid to be filtered flows through the filter cartridge, its flow direction is from the outside of the filter cartridge housing towards the outer surface of the hollow fibers (this is the normal flow direction). Therefore, the porous material of the shell wall section can effectively prevent large particles from reaching the outer surface of the hollow fibers, which could cause premature clogging.

[0016] Filter cartridge housings can be provided with only one housing wall segment made of a porous material. Two, three, or more housing wall segments can also be provided within the filter cartridge housing. Each housing wall segment can be made of the same porous material or of different porous materials.

[0017] According to a preferred embodiment of the invention, the porous material of the housing wall section includes an adsorbent material for removing unwanted components from the liquid flowing through it. This adsorbent material can be, for example, activated carbon or zeolite. Ion exchange resins or lead removal materials can also be used as adsorbent materials. Therefore, as the liquid enters or exits the filter cartridge housing, the housing wall section can remove unwanted substances that adversely affect the odor or taste of the liquid without the need for additional filter elements including activated carbon, zeolite, or any other similar materials. The filter cartridge according to this embodiment is particularly suitable for drinking water filtration devices.

[0018] According to another advantageous embodiment of the invention, the porous material of the housing wall segment comprises a dimensionally stable sintered element made of metal, ceramic, or plastic. This sintered element, made of metal, ceramic, or plastic, provides highly efficient mechanical filtration, removing particles with a diameter larger than the pore size of the porous material. Even with relatively small wall thicknesses, such as those similar to those of a filter cartridge housing made of an impermeable polymer material, the housing wall segment made of sintered metal or ceramic material exhibits good mechanical stability. The average pore size of the housing wall segment can be easily preset by pre-treating the metal or ceramic particles used in sintering during the manufacturing process of the sintered element. Therefore, the manufacture of the housing wall segment simplifies and reduces the cost of manufacturing a pre-filter suitable for use in combination with a hollow fiber membrane filter.

[0019] Due to the smaller space requirements of filter cartridges with housing wall sections made of porous material, the effective volume within the filtration device's container is larger than that of conventional filter cartridges. Furthermore, this porous material can be made of or include adsorbent material, which is cured through a sintering process to form a dimensionally stable and porous housing wall section. This porous housing wall section enables mechanical and chemical treatment of the liquid flowing through it. Therefore, the porous housing wall section achieves effective filtration without occupying additional internal space, resulting in a very compact and efficient filter cartridge design.

[0020] Similarly, particulate material can be placed in grooves or cavities formed in the porous shell wall sections, or in a separate covering layer, such as a covering layer made of flexible fiber material. This particulate material can be made of an adsorbent material or any other chemically active material for removing unwanted particles or components from the liquid flowing through the filter cartridge. According to an advantageous aspect of the invention, the shell wall sections are covered with a flexible fiber material. This flexible fiber material can be a nonwoven fabric comprising sheet-like or mesh-like structures in which fibers or filaments are entangled together mechanically, thermally, or chemically. The flexible fiber material can also be a textile material comprising woven or knitted fibers. The flexible fiber material can also be a meltblown fiber material. The mesh size of the flexible fiber material can be adjusted to provide additional filtration effect. The textile material can be arranged relative to the filter cartridge shell to completely enclose the filter cartridge shell, including the shell wall sections made of porous material, for example, like a bag or pouch enclosing the filter cartridge shell, which can be replaced after a predetermined service life or after a visual inspection of the flexible fiber material. This flexible fiber material can also be formed into a cover whose size matches the housing wall section. The cover, made of this flexible fiber material, is installed on the outer surface of the housing wall section and preferably completely covers it. This flexible fiber material (whether nonwoven or woven) can provide a low-cost additional filter element that can be easily attached to the filter cartridge housing, for example, by adhesive or bonding to secure the flexible fiber material to the outer surface of the filter cartridge housing. This flexible fiber material eliminates the need for a dedicated housing or additional fastening devices for attaching the flexible fiber material to the filter cartridge housing.

[0021] According to an advantageous aspect of the invention, the filter cartridge housing includes a first end face element and a second end face element, and a housing wall segment made of a porous material connects the first and second end face elements, thereby providing the filter cartridge housing with a unique dimensionally stable material disposed between the first and second end face elements. In this embodiment, the housing wall segment made of porous material extends from the first end face to the second end face and forms a very large surface area for liquid conduction between the exterior of the filter cartridge housing and the outer surface of the hollow fibers inside the filter cartridge housing. The housing wall segment may also extend only a portion of the longitudinal extension from the first end face to the second end face, thereby forming an annular housing wall segment located between the first and second end faces of the filter cartridge housing. The cross-section of the filter cartridge housing may be circular or elliptical. The filter cartridge housing may also have a rectangular or polygonal cross-section. The cross-section may be defined by two end faces, thereby making the filter cartridge housing cylindrical. However, for ease of insertion of the filter cartridge into the filter holder, a conical or tapered cross-section near one or both end faces may be more advantageous.

[0022] The shell wall segment can be manufactured in one piece to form a monolithic shell wall segment. Alternatively, multiple shell wall segment elements can be manufactured and combined to form a shell wall segment. One or two end faces can be composed of end face elements made of a liquid-impermeable material. These end face elements can be manufactured, for example, by injection molding.

[0023] In another advantageous aspect of the invention, the second end face element is also made of a porous material. The second end face element can be integrally formed with the housing wall segment. Alternatively, the housing wall segment and the second end face element can be manufactured separately and then combined to form a housing component. The housing wall segment or multiple housing wall segments and the second end face element can be made of the same porous material or different porous materials. Preferably, the housing wall segment and the second end face element are integrally formed and made of the same porous material.

[0024] According to a preferred embodiment of the invention, the housing wall segment has a hollow cylindrical shape, and hollow fibers are arranged within the hollow cylindrical shape of the housing wall segment, wherein one end of the hollow fiber passes through an opening on a first end face of the hollow cylindrical shape of the housing wall segment. Preferably, the hollow cylindrical shape has a circular cross-section. The internal space enclosed by the housing wall segment may be filled with hollow fibers extending from the first end face to a second end face opposite to the first end face. If the design of the filtration system requires only or can only have one filter cartridge outlet, each hollow fiber may have a first open end through the first end face of the filter cartridge housing, while the second end of the hollow fiber is closed to prevent unwanted leakage of liquid from the second end of the hollow fiber. The second end of the hollow fiber may also be sealed, for example, by embedding the second end of the hollow fiber in a cured adhesive or plastic material for sealing all the second ends of the hollow fiber, with all the second ends of the hollow fiber embedded in the adhesive or plastic material before the curing process is complete.

[0025] In another highly advantageous embodiment, the hollow fibers have at least one curved section inside the filter housing, and both ends of each hollow fiber pass through openings on the first end face of the filter housing. Therefore, both ends of the hollow fibers can be used to drain liquid from inside the filter housing. For example, each hollow fiber can have a U-shaped path inside the filter housing, such that both open ends of each hollow fiber pass through openings located on the first end face of the filter housing. Combined with the large surface area of ​​the housing wall (e.g., the housing wall is hollow cylindrical), this filter element can provide a large inlet defined by the surface area of ​​the housing wall and a large outlet defined by the sum of the cross-sectional areas of the two ends of all the hollow fibers. Therefore, this filter element requires only a small space to achieve a large liquid flow rate during filtration.

[0026] According to the invention, and according to another aspect of this embodiment, the hollow cylindrical second end face of the housing wall segment is liquid-tightly sealed by a cover. The cover may be formed of an end face element that is attached to and liquid-tightly sealed to the second end face of the hollow cylindrical housing wall segment, such that the cross-sectional shape of the second end face and its corresponding cover can have any desired shape, such as circular, elliptical, rectangular, or polygonal. Attached Figure Description

[0027] The invention will be more fully understood and further features will become apparent upon reference to the following detailed description and accompanying drawings. The drawings are representative only and are not intended to limit the scope of the claims. In fact, it will be understood by those skilled in the art, upon reading the following specification and viewing the drawings, that various modifications and variations can be made without departing from the innovative concept of the invention. Similar components depicted in the drawings are referenced by the same reference numerals.

[0028] Figure 1A cross-sectional schematic diagram of a filter element is shown, which includes a filter element housing and hollow fibers arranged within the filter element housing.

[0029] Figure 2 Showing Figure 1 The filter element shown is along Figure 1 Cross-sectional view of line II-II in the middle.

[0030] Figure 3 A cross-sectional schematic diagram of another embodiment of the filter element is shown.

[0031] Figure 4 A perspective view showing another embodiment of the filter element, and

[0032] Figure 5 Showing with Figure 1 and Figure 3 akin Figure 4 A partial schematic diagram of a cross-sectional view of an embodiment of the filter element shown. Detailed Implementation

[0033] Figure 1 and Figure 2 Different cross-sectional views of a filter element 1 suitable for and intended for use in a filtration system for drinking water treatment are shown. The filter element 1 includes a tubular filter housing 2 and a plurality of hollow fibers 3 arranged inside the filter housing 2. These hollow fibers extend along a straight line from a first end face 4 of the filter housing 2 to a second end face 5 opposite to the first end face 4.

[0034] The first end 6 of each hollow fiber 3 passes through an opening 7 on the first end face element 8 covering the first end face 4 of the tubular filter element housing 2. Therefore, any liquid inside the hollow fiber 3 can flow out of the filter element 1 through the opening 7 on the first end face element 8 at the first end face 4. The second end face 5 of the filter element housing 2 is sealed by a second end face element 9. The second end 10 of each hollow fiber 3 is embedded in the second end face element 9 and thus sealed.

[0035] The filter element 1 also includes a housing wall section 11 made of porous material. For example... Figure 2 As shown, the housing wall section 11 is a hollow cylinder with a circular cross-section. The housing wall section 11 may be made of, for example, sintered metal or ceramic material. The porous material allows liquid (e.g., water) to permeate through the housing wall section 11 and flow into the interior of the filter element 1. The liquid then permeates into the hollow fiber 3 and flows out of the filter element 1 through the opening 6 at the first end of the hollow fiber 3, which passes through the opening 7 of the first end face element 8.

[0036] The pore size of the porous material limits the particle size that can enter the filter element 1. The pore size of the porous material is adapted to the pore size of the hollow fiber 3, so that the porous material of the shell wall section 11 acts as a pre-filter for the hollow fiber 3. The shell wall section 11 can prevent larger particles suspended in the liquid from entering the filter element shell 2. These larger particles would cause premature clogging of the hollow fiber 3, thereby reducing the filtration efficiency of the filter element 1 in the early stages of its service life. The shell wall section 11 can also be made of materials such as activated carbon or zeolite, thereby further removing odors from the liquid flowing into the filter element shell 2 and filtered by the hollow fiber 3.

[0037] Figure 3 Another embodiment of filter element 1 is shown, which has the same characteristics as... Figure 1 The illustrated embodiment uses a similar filter housing 2. However, each hollow fiber 3 extends along a U-shaped path inside the filter housing 2, such that both ends 6 and 10 (i.e., the first end 6 and the second end 10) of each hollow fiber 3 pass through the opening 7 of the first end element 8 covering the first end face 4 of the tubular filter housing 2. Figures 1 to 3 In the two embodiments shown, the shell wall segment 11 extends from the first end face 4 to the second end face 5 and provides the only dimensionally stable material and element located between the first end face 4 and the second end face 5. In this application, the hollow fiber 3 is considered to be fragile and lacks dimensional stability.

[0038] Because the hollow fibers 3 are U-shaped, and the two ends 6 and 10 of each hollow fiber 3 pass through the opening 7 and the first end face 4 respectively, the fluid entering the hollow fibers 3 can be effectively discharged through the opening 7 and flow out from the filter element 1. Furthermore, the shell wall section 11 provides a very large permeable surface area, allowing liquid to enter the interior of the filter element housing 2. Therefore, the filter element 1 according to the present invention can achieve highly efficient filtration of liquids by utilizing a pre-filter formed by the shell wall section 11 and a hollow fiber membrane filter formed by the hollow fibers 3. Since the shell wall section 11 is an integral part of the filter element housing 2, it does not require additional space inside or outside the filter element housing 2; therefore, the space required by the filter element 1 is very small compared to the filtration efficiency provided by the filter element 1.

[0039] Figure 4 and Figure 5Perspective and sectional views of another embodiment of the filter element 1 are shown. The filter element housing 2 includes a hollow cylindrical housing frame 12 with multiple openings 13. Within each opening 13, a corresponding housing wall segment 11 of suitable size and matching wall thickness is provided. The housing wall segment 11 can be installed into the opening 13 of the housing frame 12 of the filter element housing 2 by adhesive bonding or press-fitting. Due to the matching size and wall thickness, the outer surface of the housing wall segment 11 is flush with the outer surface of the adjacent wall of the housing frame 12 of the filter element housing 2, and the inner surface of the housing wall segment 11 is also flush with the inner surface of the adjacent wall of the housing frame 12. Therefore, the housing wall segment 11, made of porous material, provides an inlet for fluid to enter the interior of the filter element housing 2 and provides additional filtration for the liquid flowing through the filter element 1, without requiring a large space compared to conventional filter element housings 2 known in the prior art.

[0040] The housing wall section 11 may be covered with a cover 14 made of a flexible fiber material (such as non-woven or woven fabric). The flexible cover 14 may be fixed to the outer surface of the housing frame 12 by adhesive or welding. The mesh size of the flexible fiber material may be adjusted to prevent large particles suspended in the liquid from entering the interior of the filter cartridge housing 2. The housing wall section 11 may also be made of materials such as activated carbon to provide additional and different treatment for the fluid flowing through the filter cartridge 1.

Claims

1. A filter element (1) for a liquid filtration system, comprising a filter element housing (2) and a plurality of hollow fibers (3) arranged within the filter element housing (2), the hollow fibers (3) forming a hollow fiber membrane filter, wherein, At least one end of the hollow fiber (6, 10) passes through an opening (7) in the filter housing (2), characterized in that the filter housing (2) includes at least one housing wall segment (11) made of porous material, and the housing wall segment (11) provides a liquid-conducting connection between the outside of the filter housing (2) and the outer surface of the hollow fiber (3) inside the filter housing (2).

2. The filter element (1) according to claim 1, characterized in that, The housing wall section (11) provides the only liquid-conducting connection between the outside of the filter housing (2) and the outer surface of the hollow fiber (3) inside the filter housing (2).

3. The filter element (1) according to claim 1 or 2, characterized in that, The porous material of the shell wall section (11) includes an adsorbent material.

4. The filter element (1) according to any one of the preceding claims, characterized in that, The porous material of the shell wall section (11) includes dimensionally stable sintered elements made of metal, ceramic or plastic.

5. The filter element (1) according to any one of the preceding claims, characterized in that: The shell wall section (11) is covered with flexible fiber material.

6. The filter element (1) according to any one of the preceding claims, characterized in that, The filter housing (2) includes a first end face element (8) and a second end face element (9), and a housing wall segment (11) made of porous material connects the first end face element (8) and the second end face element (9), wherein the housing wall segment (11) provides the only dimensionally stable material of the filter housing (2) located between the first end face element (8) and the second end face element (9).

7. The filter element (1) according to claim 6, characterized in that, The second end face element (9) is made of porous material.

8. The filter element (1) according to any one of the preceding claims, characterized in that, The shell wall section (11) has a hollow cylindrical shape, and the hollow fiber (3) is arranged in the hollow cylindrical shape of the shell wall section (11), wherein at least one end (6, 10) of the hollow fiber (3) passes through an opening (7) at the first end face (4) of the hollow cylindrical shape of the shell wall section (11).

9. The filter element (1) according to any one of the preceding claims, characterized in that, The hollow fiber (3) has at least one bent portion inside the filter housing (2), and both ends (6, 10) of each hollow fiber (3) pass through the opening (7) at the first end face (4) of the filter housing (2).

10. The filter element (1) according to claim 8 or 9, characterized in that, The hollow cylindrical second end face (5) of the shell wall section (11) is liquid-tightly sealed by a cover.

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