JPH07727A - Flexible tubular filter medium - Google Patents

Abstract

PURPOSE:To cause no bending clogging that follows even when a casing where a filter element is installed is bent in an arbitrary shape and to keep a uniform and stable pore diameter by integrating central yarn braided intersecting braid ing yarn in the longitudinal direction into braiding yarn that rotates on both sides and along the longitudinal direction. CONSTITUTION:Since central yarn 2 is integrated into braiding yarn 1, extension and contraction of a flexible tubular filter medium in the longitudinal direction are restrained to improve the dimension stability, allowing stable filter performance to be obtained. That is, the main role of the braiding yarn 1 is to capture particles, while that of the central yarn 2 is to fix the structure of the flexible tubular filter medium. Further, the central yarn 2 is unevenly distributed in the flexible tubular filter medium, and particularly for the flexible tubular filter medium with large bending deformation, there is no central yarn 2 on the filter medium surface receiving compression and elongation by bending deformation. The central yarn 2 is preferably distributed unevenly in the intermediate part of compression and elongation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is capable of removing particles contained in a fluid, particularly particles contained in a liquid such as water, oil or fuel, and having a uniform pore size without bending clogging. The present invention relates to a flexible tubular filter medium.

[0002]

2. Description of the Related Art A gas filter for removing particles in a fluid
Liquid filters are used in a wide range of fields such as machine tools and automobiles to protect equipment. Generally, particles that are contained in a fluid, especially particles that are contaminants in liquids such as water, oil, and fuel, are removed by using filter paper made of pulp, non-woven fabric made of synthetic fibers, or a mesh of metal or synthetic resin. A chrysanthemum-shaped filter formed by folding and molding a sheet filter medium is used. However, in recent years, from the viewpoint of high performance and space saving of these devices, even if the filters used for them are made uniform in pore size and further the filter is incorporated into the piping system and the pipe is bent and used. There is a demand for a filter that does not bend and block, and it is in a situation where conventional sheet filter media cannot handle it.

Regarding the uniformity of the pore diameter of the filter, since the fibers of the filter paper made of pulp and the nonwoven fabric made of synthetic fibers are intricately entangled with each other, the size, arrangement and shape of the pores are random. Therefore, if a structure that completely removes particles of a certain size or larger that damages the equipment is completely removed, many small particles that do not affect the equipment will be trapped in the filter, and as a result, the filter will be clogged quickly and the filter will be blocked. Shortens the life of. Further, in the sheet filter medium, it is impossible to process the filter element into any shape other than the cylindrical shape for structural reasons. On the other hand, a tubular filter medium composed of a round braided structure is a filter medium that is flexible and can be incorporated into a piping system so that it does not bend and close even when the pipe is bent and used. When pressure or pressure is applied, the filter medium expands or contracts in the longitudinal direction, which changes the pore size of the filter medium.

[0004]

In view of the above points, the present invention bends a casing provided with a filter element into an arbitrary shape in removing particles contained in a fluid, particularly particles in a liquid. It is an object of the present invention to provide a flexible tubular filter medium which does not cause bending clogging even when processed and has a uniform and stable pore diameter against external force.

[0005]

The present inventors have proposed a filter-
In order to obtain a flexible tubular filter medium that has a regular and uniform hole diameter, arrangement, and shape, and that does not cause bending blockage even if a casing with a filter element attached is bent into an arbitrary shape, The present invention has been achieved as a result of intensive studies, focusing on a round braid, which is a flexible tube in which the twisted and counterclockwise braids intersect to form a square, diamond, or triangular hole.

[0006] The present invention relates to a flexible tubular filter medium comprising a round braided tissue, in which a central yarn is incorporated. In the present invention,
The round punched braided structure is composed of a braided thread which spirally rotates in both left and right directions and along the longitudinal direction. In the flexible tubular filter medium of the present invention, a central thread is incorporated into these braided threads to form a tubular structure. To be done. The central yarn is a yarn that is braided in the circularly braided fabric structure while rotating in both the left and right directions and along the longitudinal direction, while intersecting these braid yarns in the longitudinal direction.

In the present invention, the braided yarn constituting the flexible tubular filter medium is in the form of a multifilament which is an aggregate of monofilaments or long fibers, or a spun yarn or a processed yarn which is an aggregate of short fibers. Fibers are semi-synthetic fibers such as cellulose and viscose, synthetic fibers such as polyester, polyolefin, polyamide, acrylic, polysulfone, polyamideimide, polyimide, polyphenylene sulfide and polyvinylidene fluoride, and inorganic materials such as glass, carbon and metal. Fibers, which can be used as yarns in which these fibers are used alone or as a mixture, and yarns which are resin-impregnated.

In the present invention, it is preferable that the braided yarn constituting the flexible tubular filter medium has no fluff. When the braid has fluff, the surface and the inside of the pores formed at the intersections of the braid are covered with fluff, which traps small particles that do not need to be trapped, resulting in a filter element The life is shortened. Therefore, monofilaments, resin-impregnated filaments and spun yarns are preferable.

In the present invention, the fineness of the braided yarn constituting the flexible tubular filter medium is 10 to 5,000 denier, preferably 20 to 2,000 denier, more preferably 30 to 100 denier.
It is 0 denier. If it is less than this, the filter material lacks sufficient pressure resistance, and if it exceeds this, the porosity becomes small and the filtration performance deteriorates.

In the present invention, it is important that the flexible tubular filter medium incorporates a central thread. By incorporating the central yarn into the braid, expansion and contraction of the flexible tubular filter medium in the longitudinal direction is suppressed, dimensional stability is improved, and stable filtration performance is obtained. That is, while the main function of the braiding thread is to trap particles, the main function of the central thread is to fix the tissue of the flexible tubular filter medium. In the present invention, spun yarn, monofilament, multifilament and the like can be mentioned as the raw yarn used for the central yarn.
Among them, monofilament is particularly preferable. in addition,
It is important that the central yarn is unevenly distributed in the flexible tubular filter medium. In particular, in the case of a flexible tubular filter medium having a large bending deformation, the bending deformation causes a smooth deformation because there is no central yarn on the surface of the filter medium that is subjected to compression and extension, and it is preferable that the central yarn is present in the intermediate portion between compression and extension. It is better to distribute them unevenly.

An example of this arrangement is shown in FIG. 1 as a cross-sectional view of a tubular filter medium. In the present invention, the uneven distribution of the central yarns may be unevenly distributed in one place instead of being arranged in two opposite positions as described above. An example of this arrangement is shown in a sectional view of the tubular filter medium in FIG. 1 and 2, indicates a braid and a central yarn.

In the present invention, the central yarn has a fineness of 10 to 2000 denier, preferably 20 to 100 denier.
It is 0 denier, more preferably 30 to 500 denier. If it is less than this, sufficient dimensional stability cannot be obtained, and if it exceeds this, the hole diameter and shape formed at the intersection of the braiding yarns will be greatly different from the other portions at the portion intersecting the central yarn. When the number of the central yarns is small, sufficient dimensional stability cannot be obtained, and when the number of the central yarns is large, the flexibility of the filter medium is impaired. Therefore, the number of the central yarns is 25% or less, preferably 20% or less. Yes, the number of normal central threads is 1 to 1
It is 0.

In the present invention, the length of the tubular filter medium is 5 to 2
00 cm is preferable, and more preferably 10 to 50 cm. If it is not within this range, the filter element becomes large, or the flow in the filter becomes non-uniform and the filtration performance is deteriorated.

In the present invention, the cross-sectional shape of the tubular filter medium may be circular, elliptical, rectangular, triangular or the like. Further, the cross-sectional shape of the tubular filter medium may be the same or different in the longitudinal direction. In the present invention, the diameter of the tubular filter medium is not particularly limited, but is preferably 2 mm.
˜100 mm, more preferably 5 mm to 50 mm.

One end of the tubular filter medium in the present invention is closed and the other end is opened, and the closed end is closed by heat welding treatment, adhesive fixing treatment, caulking treatment or the like. On the other hand, the open end is treated with a ring-shaped metal fitting or plastics and set in the filter casing. In the present invention, the fluid flow may be either inside or outside the tubular filter medium or outside or inside.

The controllable pore size of the flexible tubular filter medium of the present invention is from 10 μm to 5000 μm, and this pore size can be freely selected depending on the particle size to be removed.
Regarding the pore size distribution of the flexible tubular filter medium in the present invention,
Although not particularly limited, when the preferable range is illustrated, the coefficient of variation with respect to the average pore diameter is preferably 500% or less, and more preferably 300% or less. Hereinafter, the present invention will be described in more detail with reference to Examples.

[0017]

Example 1 Using a round striking machine with 64 strokes, 250 denier
2 polyester monofilaments of
Two central yarns of 0 denier polyester monofilament were put in to produce a flexible tubular filter medium. The obtained flexible tubular filter medium had a length of 300 mm, an outer diameter of 6.8 mm, a thickness of 0.33 mm, a basis weight of 228 g / m ² , an average pore size measured by an optical microscope of 350 μm, and a coefficient of variation of 2
It was 80%. One end of the flexible tubular filter medium was fixed with an epoxy resin to form a closed end, which was inserted into a Viton rubber casing having an inner diameter of 10 mm to form 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 80% glycerin aqueous solution, was flown into this filter assembly at a flow rate of 2 l / min. And then filtered. During this period, the amount of particles captured in the filter assembly and the amount of particles that passed through were measured by a gravimetric method,
The collection efficiency was measured for each particle size. Also, add 8 g of sea sand (particle size of 177 to 420 μm) to this filter assembly.
Single-pass filtration was carried out by inflowing a particle suspension having a concentration of 1 g / liter uniformly dispersed in a 0% glycerin aqueous solution at a flow rate of 5 liter / min. The time until the pressure loss of the filter assembly reached 0.5 kg / cm ² was measured as the life of the filter assembly, which was 38 minutes.

[0019]

Comparative Example 1 For comparison, a non-woven fabric made of polypropylene having an average fiber diameter of 70 μm (area weight: 49 g / m ² , thickness: 0.
26 mm) is pleat-folded with a pleat width of 15 mm, and the outer diameter is 6
A chrysanthemum-shaped element having a size of 5 mm, an inner diameter of 35 mm and a height of 30 mm was manufactured. This filter element has an outer diameter of 70 m
The filter assembly was inserted into a casing having a height of 35 mm and a height of 35 mm. The filtration performance of this filter assembly was measured under the same measurement conditions as in Example 1. Life is 4
It was 1 minute.

Table 1 shows the measurement results of Example 1 and Comparative Example 1 and shows the collection efficiency for each particle size. Example 1 of the filter assembly made of the flexible tubular filter medium of the present invention has a very sharp distribution of pore diameters as compared with Comparative Example 1 of the conventionally used non-woven fabric filter assembly, and therefore, the pore diameter is equal to or larger than the pore diameter. It was found that only particles can be separated completely, resulting in a long life.

[0021]

[Comparative Example 2] A non-woven fabric made of polypropylene having a fiber diameter of 70 μm (unit weight: 49 g / m ² , thickness: 0.26 mm) was processed into a tube having an outer diameter of 7 mm and a length of 300 mm, and one end of the opening was hardened with an epoxy resin. When the filter assembly was closed and inserted into a Viton rubber casing having an inner diameter of 10 mm, a filter assembly was manufactured, and the filtration performance was measured under the same measurement conditions as in Example 1 above. The collection efficiency of was obtained as shown in Table 2. The collection efficiency for each particle size of Comparative Example 2 was the same as that of Comparative Example 1, and the life was shorter than that of Example 1.

[0022]

Example 2 and Comparative Example 3 The filter described in Example 1
The assembly and the filter-assembly described in Comparative Example 2 were each similarly bent with a radius of curvature of 500 mm,
The filtration performance was measured under the same conditions as in Example 1. The collection efficiency for each particle size is shown in Table 3. The life is 40 minutes in the example,
The comparative example was 4 minutes.

In Comparative Example 3, it is considered that when the casing provided with the filter medium was bent, the tubular filter medium could not follow it and the pipe was blocked due to bending, resulting in deterioration of the filtration performance.
On the other hand, Example 2 is in agreement with the results of Example 1, and no reduction in filtration performance was observed, which means that the flexible tubular filter medium of the present invention has a very small change in pore size even with bending deformation. It shows that the filter material is small and does not bend and close.

[0024]

[Embodiment 3] Using a round striking machine of 48 strokes, 150 deniers
The nylon monofilament is used as the braiding yarn, and the center yarn is assembled by using two glass roving yarn prepregs (yarn diameter 200 μm) impregnated with epoxy resin.
Then, heat treatment was performed at 150 ° C. for 30 minutes to bond the central yarn and the braid to each other. The obtained flexible tubular filter medium has an outer diameter of 4 m.
m, thickness 0.2 mm, basis weight 150 g / m ² , average pore size 130 μm. A filter assembly was manufactured from this flexible tubular filter medium in the same manner as in Example 1. Next, with the filter assembly bent to a radius of curvature of 300 mm, filtration was performed under the same conditions as in Example 1 using one type of test dust, and the collection efficiency and life of each particle size were measured. As a result, the life was 29 minutes, and the collection efficiency for each particle size was as shown in Table 4. In Example 3, as in Examples 1 and 2, the pore size distribution is very sharp, so that only particles having a pore size or more can be completely separated, and the change in pore size due to bending deformation is extremely small, and bending is possible. It was found to be an excellent filter medium that does not clog.

[0025]

[Comparative Example 4] In the production of Example 1, two central yarns of 250 denier polyester monofilament were not used, but only a braid of two composite yarns of 250 denier polyester monofilament was used. Comparative Example 4 of the filter medium was manufactured. The obtained comparative example 4 has a length of 300 mm and an outer diameter of 6.5 m.
m, the thickness was 0.33 mm, and the basis weight was 190 g / m ² .
A filter assembly was manufactured from this flexible tubular filter medium in the same manner as in Example 1, and the filtration performance was measured under the same conditions as in Example 1. The life was 41 minutes, and the collection efficiency for each particle size was The results shown in Table 5 were obtained.

[0026]

EXAMPLE 4 and COMPARATIVE EXAMPLE 5 The filter assembly described in Example 1 and the filter assembly described in Comparative Example 4 were each loaded with 30 in the extending direction of the filter medium.
Tension was similarly applied at 0 g, and the filtration performance was measured under the same conditions as in Example 1. The collection efficiency for each particle size is shown in Table 6. The life was 38 minutes in the example and 23 minutes in the comparative example.

It is considered that in Comparative Example 5, the filtration performance and the life of Comparative Example 4 were significantly changed because the pore size of the filter medium was changed by the external force. On the other hand, in Example 4, the results of Example 1 are in agreement, and no change in filtration performance and life is observed,
This indicates that the flexible tubular filter medium of the present invention is an excellent filter medium in which the change of the pore diameter is extremely small even with an external force and stable filtration performance can be obtained.

[0028]

As described above, since the flexible tubular filter medium of the present invention has more accurate filtration accuracy than the conventional filter paper or the non-woven fabric filter medium, it is possible to completely capture only the particles to be removed, In addition, even if the pipe is incorporated into a pipe system and the pipe is bent and used, the tubular filter medium does not cause bending and blockage due to its flexibility, and has an excellent effect that stable filtration performance against external force can be obtained. Further, the flexible tubular filter medium of the present invention can be applied to gas as well as liquid.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a tubular filter medium showing an arrangement example in which central yarns are arranged at two opposite positions, where is a braid and is a central yarn.

FIG. 2 is a cross-sectional view of a tubular filter medium showing an arrangement example in which a central yarn is arranged at one place, where is a braid and is a central yarn.

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

Claims (1)

[Claims] 1. A tubular filter medium composed of a round braided tissue,
A flexible tubular filter medium, characterized in that a central yarn, which is braided in the longitudinal direction so as to intersect with the braid yarn, is incorporated in the braid yarn that rotates both left and right and along the longitudinal direction.