Cartridge filter and its manufacturing method

Abstract

To provide a filament winding-type cartridge filter that is high in filtration efficiency and low in ventilation resistance and liquid permeation resistance, and a method of manufacturing the same.SOLUTION: In a cartridge filter having a perforated core material 1 and a filter layer 2 formed by winding a filament on the perforated core material 1, the filter layer 2 comprises a first filter layer 21 that is formed on the perforated core material 1, a second filter layer 22 that is formed on the first filter layer 21, and a third filter layer 23 that is formed on the second filter layer 22. The second filter layer 22 is higher in thread density than the first and third filter layers 21 and 23.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention is a filament-wound cartridge filter having a structure in which a filament is wound around a perforated core material. and its manufacturing method Regarding. [Background technology]

[0002] Cartridge filters used for filtering liquids and gases include those in which spun yarn or multifilament is wound around a cylindrical perforated core, those in which a sheet-like or thread-like nonwoven fabric is wound around a cylindrical perforated core, and those in which a nonwoven fabric sheet itself is processed into a cylindrical shape without using a core. A cartridge filter has also been proposed in which a filtration layer with a lower fiber density than the cylindrical filtering material is formed by winding sliver or multifilament around the outer periphery of a cylindrical filtering material made from a thermally bondable composite fiber web composed of two components with different melting points (see Patent Document 1).

[0003] These cartridge filters are selected and used appropriately depending on the application and required performance, and filament-wound cartridge filters in particular are used in a wide range of applications because they do not require large-scale equipment and can be manufactured at low cost. For example, a filament-wound cartridge filter has been proposed in the past, which is made of polyolefin, has substantially no fiber oil attached, and is manufactured using multifilaments that have been crimped with a fluid (see Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 3-32917 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-138335 Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional filament-wound cartridge filters have problems in that when the filaments are tightly wound to improve filtration efficiency (particle removal efficiency), the airflow resistance and liquid flow resistance increase, limiting the amount of material that can be processed at one time and shortening the filter's lifespan.

[0006] Therefore, the present invention provides a filament-wound cartridge filter that has high filtration efficiency and low resistance to air and liquid passage. and its manufacturing method The purpose is to provide. [Means for solving the problem]

[0007] The cartridge filter according to the present invention has a perforated core material and a filtration layer formed by winding filaments around the perforated core material, the filtration layer comprising a first filtration layer formed on the perforated core material, a second filtration layer formed on the first filtration layer, and a third filtration layer formed on the second filtration layer, the second filtration layer having a higher thread density than the first filtration layer and the third filtration layer, and the thread density of the second filtration layer is d (g / cm 3 ), the yarn density of the first filtration layer and the third filtration layer is 0.9d (g / cm 3 )below and the thread density of the first filtration layer is 0.1 to 0.4 g / cm 3 and the thread density of the second filtration layer is 0.2 to 0.7 g / cm 3 and the thread density of the third filtration layer is 0.1 to 0.4 g / cm 3 It is of the type. In the cartridge filter of the present invention, the thread density of the first filtration layer and the third filtration layer is set to, for example, 0.7 d (g / cm 3 ) or less 。

[0008] The method for manufacturing a cartridge filter according to the present invention includes a filtration layer forming step of winding a filament around a perforated core material to form a filtration layer, and in the filtration layer forming step, Thread density: 0.1 to 0.4 g / cm 3 of A first filtration layer is formed, and filaments are wound on the first filtration layer so that the thread density is higher than that of the first filtration layer. Thread density: 0.2 to 0.7 g / cm3 of A second filtration layer is formed, and filaments are wound on the second filtration layer so that the thread density is lower than that of the second filtration layer. Thread density: 0.1 to 0.4 g / cm 3 of A third filtration layer is formed, and the thread density of the second filtration layer is d (g / cm 3 ), the yarn density of the first filtration layer and the third filtration layer is 0.9d (g / cm 3 ) or less. In the filtration layer forming step, the fineness of the filaments constituting the second filtration layer may be greater than the fineness of the filaments constituting the first filtration layer and the third filtration layer. In this case, the yarn density of the first filtration layer and the third filtration layer may be, for example, 0.7 d (g / cm 3 ) can be made as follows: Alternatively, in the filtration layer forming step, the first to third filtration layers may be made of filaments having the same fineness, and the yarn density of the second filtration layer may be made higher than the yarn density of the first and third filtration layers by changing the winding conditions. 。 [Effects of the Invention]

[0009] According to the present invention, it is possible to reduce the airflow resistance and the liquid flow resistance of a filament wound cartridge filter while maintaining high filtration efficiency. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view schematically showing the configuration of a cartridge filter according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments.

[0012] Fig. 1 is a cross-sectional view showing a schematic configuration of a cartridge filter according to an embodiment of the present invention. The cartridge filter according to this embodiment is a filament-wound type cartridge filter in which a spun yarn (filament) serving as a filtering material is wound around a core material, and as shown in Fig. 1, the cartridge filter has a perforated core material 1 and a filtration layer 2.

[0013] [Perforated core material 1] The perforated core material 1 is a cylindrical member with many holes formed on its side, and the size, shape, number, and position of the holes are not particularly limited and can be selected appropriately depending on the application and required performance of the cartridge filter. The material of the perforated core material 1 is also not particularly limited, and can be made of, for example, a metal material such as stainless steel, or a resin material such as polypropylene (PP) or polyethylene terephthalate (PET).

[0014] [Filtration layer 2] The filtration layer 2 is formed by winding filaments around the perforated core material 1. The filaments constituting the filtration layer 2 may be synthetic fibers such as polyolefin fibers, polyester fibers, and nylon fibers, natural fibers such as cotton fibers, carbon fibers, or glass fibers, but polyolefin fibers are preferred in terms of performance and cost.

[0015] For example, homopolymers or copolymers of α-olefins such as ethylene, propylene, 1-butene, 3-methyl-1-butene, 3-methyl-1-pentene, and 4-methyl-1-pentene, or copolymers of these with other copolymerizable unsaturated monomers, can be used for the filaments constituting the filtration layer 2. Among these, polyethylenes such as high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultra-high molecular weight polyethylene, ethylene-vinyl acetate copolymer, and ethylene-ethyl acrylate copolymer, polypropylenes such as propylene homopolymers, propylene-ethylene block copolymers and random copolymers, and propylene-ethylene-diene compound copolymers, poly-1-butene, and poly(4-methyl-1-pentene) are preferred.

[0016] In particular, polypropylenes are preferred, and crystalline polypropylene-based resins are more preferred, from the viewpoints of chemical resistance, mechanical properties, spinnability, etc. Examples of crystalline polypropylene-based resins include crystalline isotactic propylene homopolymers, ethylene-propylene random copolymers with a low ethylene unit content, propylene block copolymers composed of a homopolymer portion made of a propylene homopolymer and a copolymer portion made of an ethylene-propylene random copolymer with a relatively high ethylene unit content, and crystalline propylene-ethylene-α-olefin copolymers in which each homopolymer or copolymer portion in the propylene block copolymer is copolymerized with an α-olefin such as 1-butene.

[0017] The filtration layer 2 of the cartridge filter of this embodiment has a three-layer structure in which a first filtration layer 21, a second filtration layer 22, and a third filtration layer 23 are laminated in this order on the perforated core material 1, and the thread density of the second filtration layer 22, which is the middle layer, is higher than the other layers (the first filtration layer 21 and the third filtration layer 23). By setting the thread density of the filtration layer 2 to coarse / fine / coarse in this way, it is possible to increase the filtration efficiency (particle removal efficiency) while keeping the airflow resistance and liquid flow resistance low.

[0018] Specifically, the thread density of the second filtration layer 22 is d (g / cm 3 ), the yarn density of the first filtration layer 21 and the third filtration layer 23 is 0.9 (g / cm 3 ) or less, and 0.7d (g / cm 3 This makes it possible to more clearly define the roles of the particle sizes to be captured by each layer, and to further increase the filtration efficiency (particle removal efficiency) while keeping the airflow resistance and liquid flow resistance low.

[0019] The thread density of each layer can be appropriately selected depending on the application and the required filtration performance. For example, in the case of a cartridge filter used for beverages, industrial chemicals, industrial water, etc., the thread density of the first filtration layer is set to 0.1 to 0.4 g / cm. 3, the thread density of the second filtration layer is 0.2 to 0.7 g / cm 3 The thread density of the third filtration layer is 0.1 to 0.4 g / cm 3 The thread density of each layer is 0.15 to 0.35 g / cm for the first filtration layer. 3 , the second filtration layer is 0.25 to 0.65 g / cm 3 , the third filtration layer is 0.15 to 0.35 g / cm 3 The first filtration layer is preferably 0.2 to 0.3 g / cm 3 , the second filtration layer is 0.3 to 0.6 g / cm 3 , the third filtration layer is 0.2 to 0.3 g / cm 3 It is more preferable to set the following.

[0020] The thread densities of the first and third filtration layers may be the same as or different from that of the second filtration layer, provided that they are lower than that of the second filtration layer. Furthermore, the thicknesses of the first to third filtration layers are not particularly limited and can be appropriately selected depending on the required filtering performance. Furthermore, the cartridge filter of this embodiment is not limited to one in which the filtration layer 2 has a three-layer structure, and may be configured with four or more layers, provided that adjacent layers have different thread densities and the thread density of the intermediate layer is higher than that of the innermost and outermost layers.

[0021] [Manufacturing method] Next, a method for manufacturing the cartridge filter described above will be described. The cartridge filter of this embodiment may be formed by winding filaments on the perforated core material 1 so as to have a coarse thread density to form a first filtration layer 21, winding filaments thereon so as to have a higher thread density than the first filtration layer 21 to form a second filtration layer 22, and further winding filaments thereon so as to have a lower thread density than the second filtration layer 22 to form a third filtration layer 23.

[0022] The thread densities of the first to third filtration layers may be adjusted, for example, by changing the thickness of the fibers constituting the filaments, or by changing the winding conditions using the same filaments. Specifically, by making the fineness of the filaments constituting the second filtration layer 22 larger than the fineness of the filaments constituting the first filtration layer 21 and the third filtration layer 23, the thread density of the second filtration layer 22 can be made higher than the thread densities of the first filtration layer 21 and the third filtration layer 23. In this case, the thread density of the second filtration layer 22 is set to d (g / cm 3 ), the yarn density of the first filtration layer 21 and the third filtration layer 23 is 0.7d (g / cm 3 ) can be made as follows:

[0023] Alternatively, for example, the first to third filtration layers 21 to 23 may be made of filaments of the same fineness, and the yarn density of the second filtration layer 22 may be made higher than the yarn density of the first filtration layer 21 and the third filtration layer 23 by changing the winding conditions. In this case, the yarn density of the second filtration layer 22 may be set to d (g / cm 3 ), the yarn density of the first filtration layer 21 and the third filtration layer 23 is 0.9d (g / cm 3 ) can be made as follows:

[0024] As described above in detail, the cartridge filter of this embodiment has a filtration layer structure of at least three layers, with the second filtration layer having a high thread density sandwiched between the first and third filtration layers having low thread densities, so that the second filtration layer increases filtration efficiency, while the first and third filtration layers reduce airflow resistance and liquid flow resistance. As a result, a filament-wound cartridge filter with high filtration efficiency and low airflow resistance and liquid flow resistance can be realized. [Example]

[0025] The effects of the present invention will be specifically described below with reference to examples and comparative examples.

[0026] <First Example> As a first example of the present invention, cartridge filters of an example and a comparative example were produced by the following method and conditions, and their performance was evaluated.

[0027] Example 1 First, a polypropylene (PP) perforated tube with an inner diameter of 30 mm and a length of 250 mm was used to assemble a filament consisting of 480 polypropylene (PP) fibers with a single fiber fineness of 11.1 dTex and a yarn density of 0.27 g / cm. 3 Next, on the first filtration layer, a filament consisting of 42,400 bundles of sheath-core composite fibers (sheath:core = 50:50) with a single yarn fineness of 0.2 dTex, a sheath material of polyethylene (PE) and a core material of polypropylene (PP) was wound to a yarn density of 0.53 g / cm. 3 The second filtration layer was formed by winding the fiber bundle over a length of 10 m so as to form a second filtration layer.

[0028] Subsequently, a filament consisting of 480 polypropylene (PP) fibers with a single fiber fineness of 11.1 dTex was applied to the second filtration layer, with a yarn density of 0.27 g / cm 3 The third filtration layer was formed by winding the spunbonded fiber over a length of 171 m so as to form a third filtration layer, thereby obtaining a cartridge filter of Example 1. The cartridge filter of Example 1 had a collection efficiency (filtration efficiency) of 50% for particles with a particle diameter of 7.5 μm and a collection efficiency (filtration efficiency) of 100% for particles with a particle diameter of 10 μm, and an airflow resistance of 340 mmAq.

[0029] Comparative Example 1 A filament consisting of 240 polypropylene (PP) fibers with a single fiber fineness of 11.1 dTex was placed in the same perforated tube as used in Example 1, and the yarn density was 0.313 g / cm. 3 The filter was wound over a length of 619 m so that the filtration layer had a single-layer structure, to obtain a cartridge filter of Comparative Example 1. The cartridge filter of Comparative Example 1 had a collection efficiency (filtration efficiency) of 60% for particles with a particle diameter of 7.5 μm, a collection efficiency (filtration efficiency) of 100% for particles with a particle diameter of 10 μm, and an airflow resistance of 640 mmAq.

[0030] Comparative Example 2 A filament consisting of 480 polypropylene (PP) fibers with a single fiber fineness of 11.1 dTex was placed in the same perforated tube as used in Example 1, and the yarn density was 0.294 g / cm. 3 The filter was wound over a length of 291 m so that the filtration layer had a single-layer structure, to obtain a cartridge filter of Comparative Example 2. The cartridge filter of Comparative Example 2 had a collection efficiency (filtration efficiency) of 10% for particles with a particle diameter of 7.5 μm, a collection efficiency (filtration efficiency) of 30% for particles with a particle diameter of 10 μm, and an airflow resistance of 220 mmAq.

[0031] The results are summarized in Table 1. The collection efficiency of each cartridge filter of Example 1 and Comparative Examples 1 and 2 shown in Table 1 was measured using a particle counter KS-42D manufactured by Rion Co., Ltd. The airflow resistance was measured using a U-tube manometer method.

[0032] [Table 1]

[0033] As shown in Table 1 above, the cartridge filter of Example 1, in which the filtration layer had a three-layer structure with the middle layer having a higher thread density than the other layers, had high filtration efficiency (collection efficiency) and low airflow resistance. In contrast, the cartridge filter of Comparative Example 1, in which the filtration layer had a single-layer structure with a relatively high thread density, had improved filtration efficiency (collection efficiency) for particles with a particle size of 7.5 μm, but the airflow resistance increased significantly to nearly twice that of Example 1. On the other hand, the cartridge filter of Comparative Example 2, in which the filtration layer had a single-layer structure with a relatively low thread density, had reduced airflow resistance but significantly reduced particle filtration efficiency (collection efficiency).

[0034] <Second Example> As a second example of the present invention, cartridge filters of an example and a comparative example were produced by the following method and conditions, and their performance was evaluated.

[0035] Example 2 A filament consisting of 480 polypropylene (PP) fibers with a single fiber fineness of 11.1 dTex was placed in the same perforated tube as used in Example 1, and the yarn density was 0.26 g / cm. 3 A first filtration layer was formed by winding a filament having 480 polypropylene (PP) fibers with a single yarn fineness of 11.1 dTex over a length of 23 m to give a yarn density of 0.31 g / cm3 onto the first filtration layer.

[0036] Subsequently, a filament consisting of 480 polypropylene (PP) fibers with a single fiber fineness of 11.1 dTex was applied to the second filtration layer, with a yarn density of 0.26 g / cm 3 The third filtration layer was formed by winding the filter over a length of 44 m so as to obtain a cartridge filter of Example 2. The cartridge filter of Example 2 had a collection efficiency (filtration efficiency) of 62% for particles with a particle diameter of 7 μm and 92% for particles with a particle diameter of 10 μm, and an airflow resistance of 542 mmAq.

[0037] Comparative Example 3 A filament consisting of 480 polypropylene (PP) fibers with a single fiber fineness of 11.1 dTex was placed in the same perforated tube as used in Example 1, and the yarn density was 0.31 g / cm. 3 The filter was wound over a length of 340 m so that the filtration layer had a single-layer structure, to obtain a cartridge filter of Comparative Example 3. The cartridge filter of Comparative Example 3 had a collection efficiency (filtration efficiency) of 45% for particles with a particle diameter of 7 μm, a collection efficiency (filtration efficiency) of 85% for particles with a particle diameter of 10 μm, and an airflow resistance of 576 mmAq.

[0038] The results are summarized in Table 2. The collection efficiencies of the cartridge filters of Example 2 and Comparative Example 3 shown in Table 2 were measured using a particle counter KS-42D manufactured by Rion Co., Ltd. The airflow resistance was measured using a U-tube manometer method.

[0039] [Table 2]

[0040] As shown in Table 2 above, the cartridge filter of Example 2, in which the filtration layer had a three-layer structure and the thread density of the middle layer was higher than that of the other layers, had a relatively high filtration efficiency (collection efficiency) and low airflow resistance. In contrast, the cartridge filter of Comparative Example 3, in which the filtration layer had a single-layer structure with a high thread density, had a lower particle filtration efficiency (collection efficiency) and a higher airflow resistance than Example 2.

[0041] From the above results, it was confirmed that the present invention can realize a filament wound cartridge filter having high filtration efficiency and low resistance to airflow and liquid passage. [Explanation of symbols]

[0042] 1 Perforated core material 2 filtration layer 21 1st filtration layer 22 2nd filtration layer 23 Third filtration layer

Claims

1. a perforated core material; a filtration layer formed by winding filaments around the perforated core material; and the filtration layer comprises a first filtration layer formed on the perforated core material, a second filtration layer formed on the first filtration layer, and a third filtration layer formed on the second filtration layer; The second filtration layer has a higher thread density than the first filtration layer and the third filtration layer, The thread density of the second filtration layer is d (g / cm ３ ), when the yarn density of the first filtration layer and the third filtration layer is 0.9 d (g / cm ３ ) or less, The first filtration layer has a thread density of 0.1 to 0.4 g / cm 3 ; The second filter layer has a thread density of 0.2 to 0.7 g / cm 3 ; The third filter layer has a thread density of 0.1 to 0.4 g / cm 3 . Cartridge filter.

2. The thread density of the first filter layer and the third filter layer is 0.7 d (g / cm ３ 2. The cartridge filter according to claim 1, wherein the pore size is 0.01 or less.

3. a filtration layer forming step of winding filaments around a perforated core material to form a filtration layer, In the filtration layer forming step, a first filtration layer having a thread density of 0.1 to 0.4 g / cm 3 is formed by winding a filament around the perforated core material, a second filtration layer having a thread density of 0.2 to 0.7 g / cm 3 is formed by winding a filament around the first filtration layer so that the thread density is higher than that of the first filtration layer, and a third filtration layer having a thread density of 0.1 to 0.4 g / cm 3 is formed by winding a filament around the second filtration layer so that the thread density is lower than that of the second filtration layer. The thread density of the second filtration layer is d (g / cm ３ ), the yarn density of the first filtration layer and the third filtration layer is 0.9 d (g / cm ３ ) or less Manufacturing method of cartridge filters.

4. The method for manufacturing a cartridge filter according to claim 3, wherein in the filtration layer forming step, the fineness of the filaments constituting the second filtration layer is made larger than the fineness of the filaments constituting the first filtration layer and the third filtration layer.

5. The yarn density of the first filter layer and the third filter layer is 0.7 d (g / cm ３ 5. The method for producing a cartridge filter according to claim 4, wherein:

6. The method for manufacturing a cartridge filter according to claim 3, wherein in the filtration layer forming step, the first to third filtration layers are made of filaments having the same fineness, and the thread density of the second filtration layer is made higher than the thread densities of the first filtration layer and the third filtration layer by changing the winding conditions.

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