JP2003326116A - Flexible tubular filter medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flexible tubular filter medium following an object formed into an arbitrary shape by bending processing to generate no folding closure, having a stable pore size with respect to the repetition of pressure or bending and having characteristics capable of easily removing adhered particles or fiber refuse in washing. <P>SOLUTION: The flexible tubular filter medium is regular and uniform in the pore size, arrangement and shape of a filter and follows even the interior of piping of which the filter arranging place is bent to generate no folding closure. This flexible tubular filter medium has round braided texture constituted of braided yarns rotated in both left and right directions and a longitudinal direction and a flexible support is inserted in the tubular filter medium in a contact state. The ratio of the contact area of the flexible support with the inner wall of the tubular filter medium is 50% or less of the area of the inner wall of the tubular filter material. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bending obstruction capable of removing particles contained in a fluid, in particular, particles contained in a liquid such as water, oil and fuel. The present invention relates to a tubular filter medium having a uniform pore size that does not cause cracking. [0002] A gas filter for removing particles in a fluid
Liquid filters are used for protecting equipment in a wide range of fields such as machine tools and automobiles. Generally, particles contained in a fluid, particularly particles that are pollutants in a liquid such as water, oil, or fuel, are removed by a so-called filter paper made of pulp, a nonwoven fabric made of synthetic fibers, or a mesh of metal or synthetic resin. A chrysanthemum flower filter obtained by folding and molding a sheet filter material is used. However, in recent years, from the viewpoint of high performance and space saving of these devices, filters used in these devices have a uniform pore diameter, and furthermore, filters can be incorporated in a piping system and used by bending piping. There is a demand for a filter that does not bend and block, and is in a situation where conventional sheet filter media cannot cope. [0003] Regarding the uniformity of the pore diameter of the filter, the size, arrangement and shape of the pores are random in filter paper made of pulp and non-woven fabric made of synthetic fibers because the fibers are intertwined in a complicated manner. Therefore, if a structure that can completely remove particles that are larger than a certain size that damages the device is used, many small particles that do not affect the device will be captured by the filter, and as a result, the filter will be clogged earlier and the filter will be caught earlier. Life is shortened. Further, in the sheet filter medium, it is impossible to process the filter element into an arbitrary shape other than the cylindrical shape for structural reasons. When the filter is used continuously, it is necessary to remove the particles adhering to the filter medium by applying a fluid in the direction opposite to the filtration direction or applying vibration at regular intervals. However, removal of things like fiber debris caught between filters with very little deformation of the filter medium, such as metal nets,
At present, it is extremely difficult to remove particles trapped in filter paper or nonwoven fabric in which fibers are intricately entangled. SUMMARY OF THE INVENTION In view of the above, the present invention has been made in consideration of the above problems, and therefore, in filtering particles contained in a fluid, particularly particles in a liquid, even if the filter is bent into an arbitrary shape. Flexibility that has a stable pore size against pressure and repetition of bending without causing bending obstruction following, while easily removing particles such as adhered particles and fiber debris during cleaning It is to provide a tubular filter medium. [0006] The present inventors have proposed a filter.
In order to obtain a flexible tubular filter medium that has a uniform and uniform hole diameter, arrangement, and shape, and that does not cause bent blockage even in a bent pipe where the filter is installed, The present inventors have focused on a round tube braid, which is a flexible tube in which a square, a rhombus, a triangle, and the like are intersected by a pair of counterclockwise braids, and as a result of intensive studies, the present invention has been reached. DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tubular filter medium having a round-punched braid structure composed of braiding yarns rotating in both the left and right directions and the longitudinal direction, wherein a flexible support is provided inside the tubular filter medium. The present invention relates to a flexible tubular filter medium, wherein a body is inserted in contact therewith, and an area where the flexible support is in contact with an inner wall of the tubular filter medium is 50% or less of an inner wall area of the tubular filter medium. In the present invention, the round braided structure is composed of braids that are spirally rotated in both the left and right directions and the longitudinal direction, and the flexible tubular filter medium of the present invention is composed of these round braided structures. It is formed by inserting a flexible support along the longitudinal direction of the inner surface. In the present invention, the braid constituting the flexible tubular filter medium is in the form of a monofilament, a multifilament which is an aggregate of long fibers, a spun yarn which is an aggregate of short fibers, or a processed yarn. Fibers are semi-synthetic fibers such as cellulose and viscose, polyester, polyolefin, polyamide, acrylic, polysulfone, polyamide imide, polyimide, polyphenylene sulfide, polyvinylidene fluoride, etc., and inorganic fibers such as glass, carbon and metal. It is a fiber, and a single or mixed yarn of these fibers or a yarn impregnated with a resin can be used. In the present invention, the braid constituting the flexible tubular filter medium preferably has no fluff. If the braid has fluff, the surface or inside of the hole formed at the intersection of the braid will be covered with fluff, thereby trapping small particles that do not need to be trapped. Life is shortened. Therefore, a monofilament, a filament impregnated with a resin, and a spun yarn are preferable. In the present invention, the fineness of the braid constituting the flexible tubular filter is 1.1 to 5500 dtex, preferably 22 to 2200 dtex, more preferably 33 to 1100 dtex.
It is. If it is less than this, the filter medium lacks sufficient pressure resistance, and if it exceeds this, the porosity decreases and the filtration performance decreases. In the present invention, the flow of the filtration fluid is from outside to inside the tubular filter medium. The flow of the fluid during washing is from inside to outside of the tubular filter medium. In the present invention, it is important that the support is incorporated in contact with the inner wall of the filter. This not only maintains the tubular structure, but also suppresses expansion and contraction of the filter medium in the longitudinal direction, improves dimensional stability, prevents misalignment, and provides stable filtration performance. In addition, since the tubular filter is made flexible by making the support flexible, the filter can be bent and used. That is, while the main role of the braid is to capture particles, the main role of the flexible support is to fix the tissue of the tubular filter and to make the tubular filter flexible. It is in. As described above, the flexible support works to suppress the deformation of the filter medium against the external pressure during filtration. on the other hand,
There is no function to suppress the expansion and contraction of the filter medium against the in-cylinder pressure.
This is very convenient for maintaining the performance of the filter medium. In other words, when the flexible filter is washed, pressure is applied from the inner surface of the tube, so that the filter medium hole is greatly opened and the filter medium is greatly expanded and contracted. As a result, the particles sandwiched between the pores of the filter medium are instantaneously released, and the particles adhering to the surface of the filter medium are also instantly released due to the shearing force at the interface. In the present invention, the form of the flexible support may be a spiral one shown in FIG. 2, a ring one shown in FIG. 3, or a net formed into a cylinder. good. However, the area of contact with the inner wall of the flexible filter medium must be 50% or less of the area of the inner wall of the tubular filter medium. If the area in contact with the inner wall of the tubular filter medium exceeds 50%, not only does the filtration area of the filter decrease, but also the pressure rise during filtration and
This is because problems such as insufficient opening of the filter medium holes at the time of washing and deterioration of washability occur. The wire used for the flexible support may be a polymer material or a metal material. There is no particular limitation on the diameter of the wire or the cycle of repetition. What is necessary is just to select the form which can ensure the required penetration resistance of the filtrate, the required flexibility of the filtration filter, and can secure the opening ratio of the filter material hole which does not impair the cleaning performance. However, when the support is in contact with a pitch wider than the period of the round braided structure in the longitudinal direction, the dimensional stability of the filter medium in the longitudinal direction may be reduced. Therefore, it is desirable that the pitch of the helix be 1/2 to 5 times the cycle of the round braided tissue. In order to further increase the dimensional stability of the filter media in the longitudinal direction, yarns with different melting points are combined to produce a tubular filter media, then a metal rod is inserted into the filter media tube, and one of the threads is fixed at the thread entanglement. Alternatively, the yarn entangled portion may be fixed or the woven shape may be stabilized by a method such as heat setting in a deforming temperature range. FIG. 1 shows an example of the arrangement of the braided yarn. In the present invention, the length of the tubular filter medium is 5 to 2
00 cm is preferable, and more preferably 200 to 120 c
m. The outer diameter is preferably from 3 mm to 200 mm, more preferably from 6 mm to 50 mm. If it is not within this range, the size of the filter element becomes large, or the flow in the filter becomes non-uniform, so that the filtration performance decreases. One end of the tubular filter medium in the present invention is closed and the other is opened, and the closed end is closed by a heat welding process, an adhesive fixing process, a caulking process, or the like. On the other hand, the open terminal is subjected to terminal treatment with a ring-shaped metal fitting or plastics, and set in a filter casing. The controllable pore size of the flexible tubular filter medium in the present invention is from 1 μm to 5000 μm, and this pore size can be freely selected depending on the particle size to be removed. The pore size distribution of the flexible tubular filter medium in the present invention is not particularly limited, but a preferred range is, for example, a coefficient of variation with respect to the average pore size of 500% or less, more preferably 300% or less. . The pore size distribution of the flexible tubular filter medium is increased and the coefficient of variation is 50
If it exceeds 0%, the rate at which small particles that do not need to be removed are captured by the filter medium increases, and as a result, the life of the filter medium is shortened. Here, the coefficient of variation is a value obtained by dividing the standard deviation of the pore diameter by the average value. Hereinafter, the present invention will be described in more detail with reference to Examples. [Example 1] Using a 64 hitting round stringing machine,
Two polyester monofilaments of 275 decitex were plied and used as a braid to produce a tubular filter medium. A stainless steel spiral support having a wire diameter of 0.6 mmφ, an outer diameter of 6.7 mm and a pitch of 4 mm was inserted into the tube of the tubular filter medium. The obtained flexible tubular filter medium has a length of 300 mm.
, Outer diameter 7 mm, thickness 0.3 mm, basis weight 213 g / m ²
The average pore diameter measured by an optical microscope was 730 μm, and the coefficient of variation was 240%. One end of the flexible tubular filter medium was fixed with an epoxy resin to form a closed end, and inserted into a case made of Viton rubber having an inner diameter of 10 mm to obtain a filter assembly. Next, 2 l of a particle suspension having a concentration of 0.2 g / l in which sea sand sieved with a standard sieve was uniformly dispersed in an aqueous 80% glycerin solution was passed through the filter assembly at a flow rate of 2 l / min. And filtered. During this time, the amount of particles captured by the filter assembly and the amount of particles passed therethrough were measured by a gravimetric method,
The collection efficiency for each particle size was measured. A 1 g / liter particle suspension in which sea sand (particle diameter: 177 to 1700 μm) is uniformly dispersed in an 80% glycerin aqueous solution is introduced into the filter assembly at a flow rate of 5 liter / min, and a single pass is performed. Filtration was performed. The time required for the pressure loss of the filter assembly to reach 0.5 kg / cm ² was measured as the life of the filter assembly, and the life was 54 minutes. Next, the operation of applying 0.3 Mpa compressed air to the filter assembly for 1 second was performed 5 times at 1 second intervals in total, and particles separated from the filter assembly were measured by a gravimetric method. As a result, the peeling rate of the particles was 99%. The results are shown in Table 1. [Table 1] Comparative Example 1 A nonwoven fabric made of polypropylene having a fiber diameter of 70 μm (basis weight: 22 g / m ² , thickness: 0.21)
mm) into a tube with an outer diameter of 7 mm and a length of 300 mm,
One end of the opening was hardened with epoxy resin and closed, and it was inserted into a case made of Viton rubber having an inner diameter of 10 mm to manufacture a filter assembly. The same measurement conditions (filtration direction, washing direction) as in Example 1 were used. (The reverse of Example 1), the filtration performance was measured, and the life was 21 minutes and the particle exfoliation rate was 78%. The measurement results of Example 1 and Comparative Example 1 are shown in Table 1 and the collection efficiency for each particle size is shown. Example 1 of the filter assembly made of the flexible tubular filter medium in the present invention has a very sharp pore size distribution as compared with Comparative Example 1 of the filter assembly made of a nonwoven fabric which has been conventionally used. It was found that only particles could be completely separated, resulting in a long life. Furthermore, it was found that it was also excellent in releasability, so that it was suitable for repeated use. Example 2 and Comparative Example 2 The filter assembly described in Example 1 and the filter assembly described in Comparative Example 2 were each similarly bent at a radius of curvature of 500 mm under the same conditions as in Example 1. The filtration performance was measured. At this time, the average pore diameter of Example 3 was 730 μm, and the coefficient of variation was 250%. Table 3 shows the collection efficiency for each particle size. The life was 53 minutes in the example and 14 minutes in the comparative example, and the peelability was 99% in the example and 72% in the comparative example. It is probable that in Comparative Example 2, when the casing provided with the filter medium was bent, the tubular filter medium could not follow the case, causing a bending blockage, resulting in a decrease in filtration performance.
On the other hand, Example 2 was consistent with the result of Example 1, and no decrease in filtration performance was observed. This indicates that the flexible tubular filter medium of the present invention had a very small change in pore diameter even with bending deformation. This shows that the filter medium is small, does not bend and block, and has excellent particle releasability. As described above, the filtering efficiency of the flexible tubular filter of the present invention is more accurate than that of the conventional filter paper or non-woven filter, so that only the particles to be removed can be completely captured. It is possible, and even if it is used by bending the filter medium, it does not cause bending and closing due to the flexibility of the tubular filter medium, and has an excellent effect that stable filtration performance can be obtained against external force. By applying a force in the opposite direction, the filter medium pores are greatly opened, so that there is an excellent effect that separation and washing of particles can be instantaneously realized. Further, the flexible tubular filter medium of the present invention can be applied to gas as well as liquid.

[Brief description of the drawings] FIG. 1 is a cross-sectional view of a tubular filter medium. FIG. 2 shows an example of a flexible support. FIG. 3 shows an example of a flexible support. [Explanation of symbols] 1. Braid 2. Spiral support

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Hiroshi Kanzaki             Toyobo, 2-1-1 Katata, Otsu City, Shiga Prefecture             Achievement Research Institute (72) Inventor Yuji Kakita             Toyobo, 2-1-1 Katata, Otsu City, Shiga Prefecture             Achievement Research Institute (72) Inventor Yoshihiro Yoshio             Toyobo, 2-1-1 Katata, Otsu City, Shiga Prefecture             Achievement Research Institute (72) Inventor Tetsuji Koyama             2-8-8 Dojimahama, Kita-ku, Osaka Toyobo             Achievement Co., Ltd. (72) Inventor Mamoru Satsuka             Toyobo, 2-9-1 Dojimahama, Kita-ku, Osaka-shi             Engineering Co., Ltd. F-term (reference) 4D019 AA03 BA02 BA03 BA04 BA13                       BA17 BB02 BC20 BD10 CA03                       CB06                 4L046 AA03 AA24 BA00 BB00

Claims (1)

Claims 1. A tubular filter medium having a braided knitted structure composed of a braid that rotates in both the left-right direction and the longitudinal direction, wherein a flexible support comes into contact with the inside of the tubular filter medium. A flexible tubular filter medium inserted, wherein the flexible support is in contact with the inner wall of the tubular filter medium.