JPH01143615A - Filter cloth - Google Patents

Abstract

PURPOSE:To raise the collection rate of filter cloth, by joining a napped cloth wherein warps are false-twisted finished yarns having single-yarn fineness of 1-8d and wefts are superfine filaments having single-yarn fineness of 0.5d or less to a net having a network structure on the reverse side. CONSTITUTION:A napped cloth is prepared by forming with false-twisted finished yarns, as warps, having the total fineness of 50-300 denier and the single- yarn fineness of 1-8 denier and superfine fiber filaments, as wefts, having the total fineness of 50-300 denier and the single-yarn fineness of 0.5 denier or less. A filter cloth is obtained by joining a net of synthetic resin having a network structure, wherein the cross-sectional configuration of linear substances of resin constituting the network is a polygon with four sides or more, or an ellipse with a degree of flattening of 1.2-3 and the network interval is 5-50mm, to the reverse side of said napped cloth. Resins for the net of synthetic resin are polyolefin and polyamide resins.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a filter cloth with good collection performance. This invention relates to a filter cloth for a self-cleaning porous drum type filtration device installed in a wastewater treatment device that separates and removes wastewater.

(Prior Art) Conventionally, as a filter cloth loaded into a self-cleaning porous drum type filtration device incorporated in a wastewater treatment device.

It uses a stainless steel filtration net or is canvas-like, woven with thick denier threads such as synthetic fibers with a filament fineness of 5 denier or more.

They have been selected based on performance such as durability, dimensional stability under vibration conditions, and cake release properties. For this reason, the filtration performance is at a fairly low level, and it is difficult to remove substances with small solid particle diameters, so it is currently necessary to use a flocculant.

(Problem that the invention attempts to solve) The present invention eliminates these drawbacks of the prior art.

The object of the present invention is to provide a filter cloth that can be incorporated into a self-cleaning porous drum type filter device that has excellent filtration performance.

(Means for Solving the Problems) In order to solve these problems, the present inventors have arrived at the two inventions as a result of intensive research.

That is, in the present invention, the warp yarns have a total fineness of 50 to 300.
False twisted yarn with denier and single yarn fineness of 1 to 8 denier.

The total fineness of the weft is 50 to 300 denier, and the single yarn fineness is 0.
．． A raised fabric made of ultrafine filament yarns of 5 deniers or less and a mesh structure on the back side of the raised fabric, 'M4
The cross-sectional shape of the resin filaments constituting the eyes is a polygon with a rectangular or larger shape, or an ellipse with an oblateness of 1.2 to 3, and is joined to a synthetic resin net having a 1M4-eye interval of 5 mm-50 fins. The gist of the filter cloth is as follows.

The present invention will be explained in detail below. The warp used in the present invention is a false twisted yarn having a total fineness of 50 to 300 deniers and a single yarn fineness of 1 to 8 deniers.

If the total fineness is less than 50 denier, the strength of the napped fabric will be low, while if it exceeds 300 denier, the weight of the fabric will increase and it will be inferior in terms of cost and operability.

In addition, if the single yarn fineness is less than 1 denier, the entire fabric becomes too soft, resulting in poor operability in adhesion processing with a synthetic resin net and increasing costs. - side, single yarn fineness is 8
If the denier exceeds the denier, the fiber gaps become large, resulting in poor collection efficiency during filtration.

In addition, by using a false twisted yarn for the warp yarn, the nap density increases due to the crimp force of the false twisted yarn, resulting in good collection efficiency.

Therefore, in the present invention, it is necessary to use a false twisted yarn having the above numerical values limited to the warp yarns.

Next, for the weft yarns constituting the nap, fiber yarns having a single yarn fineness of 0.5 denier or less and a total fineness of 50 to 300 denier are used. In filtration operations such as wastewater treatment, collection performance, especially the minimum particle size that can be collected, is important in relation to the subsequent treatment process, but the particle size that can be collected largely depends on the fineness of the single filament. However, the smaller the diameter of the single filament, the more fine particles can be collected. In the present invention, it is necessary for the single yarn fineness of the napped fabric to be 0.5 denier or less from the viewpoint of both durability and collection performance of the filtration device. The reason for limiting the value to 0.5 denier or less is 1. In the case of the self-cleaning porous drum type filtration device used in the present invention, backwashing is performed with water flow to wash out particles, etc. that have accumulated in the filter cloth. In that case, the direction of the fluff on the raised fabric changes with the water flow, and when washed, the direction of the fluff changes, resulting in high cleaning efficiency (and reducing the washing time. The direction of the fluff can be easily changed by the water flow). The fineness of single fibers must be 0.5 denier or less. By limiting the fineness to 0.5 denier or less, the collected particle size is also different from conventional filter cloth, and it is possible to collect dramatically smaller particles. In addition, the total fineness of the weft is 50~
The reason for limiting it to 300 denier is that if it is less than 50 denier, the tear strength after raising will be low;
If it exceeds 0 denier, it will increase the basis weight of the fabric and increase the cost, so it is not adopted in the present invention. The ultrafine fibers used for the weft can be any of the various methods that have been proposed so far, such as the single-component extraction method for sea-island fibers, the physical splitting method for bicomponent composite fibers, the high-speed spinning and drawing method, and the jet spinning method. Any method using high shearing force such as the above method may be used, but it is necessary that the single yarn fineness is 0.5 denier or less.

Next, in the present invention, a raised fabric is manufactured using the warp and weft. As the base fabric structure, a weft satin fabric that is easy to raise is preferable, and a double-sided weft satin fabric may be used for the purpose of improving collection efficiency. The napping process may be carried out using a belt type or hydraulic needle cloth napping machine. The reason for using this cloth raising machine is that the length of one fluff can be made relatively long, and the fluff density is increased, so that the collection efficiency can be improved.

Next, the purpose of laminating a synthetic resin net on the raised fabric is to
When used in a self-cleaning porous drum type filtration device, it has good attachment to the drum, morphological stability against vibration, dimensional stability in a closed state, etc., and is excellent in terms of work surface, operability, and durability. It becomes a filter cloth.

In addition, since the net portion is not filtered, it is necessary to keep the bonding area between the net and the raised fabric small and not deform during washing and filtration. Resins used for synthetic resin nets include polyolefin resins such as polypropylene and polyethylene, polyamide resins such as nylon 6, thermoplastic resins such as ethylene-vinyl alcohol copolymer resins, polyvinyl chloride resins, and polyacetal resins. Can be mentioned.

The purpose of the present invention is to reduce the formation of flocs due to flocculant-induced flocculant and pressurized flotation, and to apply the secondary filtration to wastewater treatment.
Alternatively, the aim is to simplify the treatment process by omitting the addition of a flocculant, and to reduce the SS of raw water as much as possible.
The purpose is to remove components. Therefore, there is no need to consider heat resistance so much, and it is sufficient to select a material with good bonding conditions.

Possible methods for bonding the raised fabric and the synthetic resin net are an adhesive method and a heat method such as high-frequency heating. In the adhesive method, it is necessary to consider the materials of the adhesive, the raised fabric, and the synthetic resin net, and in particular, in the case of polyolefin resin, the adhesive method is not preferable because it has poor adhesion with different materials. Generally, when the materials of the raised fabric and the net part are different, a heat fusion method is preferably used.1For example, when joining a synthetic resin net made of polyvinyl chloride resin and a raised fabric made of fibers such as nylon 6 or polyester, high frequency If the bonding is performed by heating, there will be less damage to the nylon 6 and polyester fibers, and only the polyvinyl chloride resin will be melted and bonded, which is advantageous in terms of strength.

In addition, when using the ultrasonic heating method, unlike the normal heating method, the melting or softening temperature of each polymer can be lowered by 10
The temperature only rises by ~20℃.

Moreover, since local (point-like) melting is possible, it has the advantage of less thermal deterioration, and is therefore preferably used for the purposes of the present invention.

Next, regarding the shape of the synthetic resin net 5, the mesh spacing is 5 to 50n, preferably 10 to 30n.

Polygonal shapes such as triangular, square, and hexagonal shapes are preferably used as the shape of the mesh. This is preferable from the viewpoint of the strength of the synthetic resin net with a filtration efficiency of 9. When the mesh spacing is less than 5 dragons, the adhesion between the raised fabric and the net will be good, but the effective filtration area will be small and the filtration efficiency will be poor. When the mesh spacing exceeds 50 mm, the effective filtration area increases and the filtration efficiency improves. However, when the filter cloth is backwashed, the cloth is easily deformed by the force of the water flow, and the adhesive force is weak, so peeling may occur, resulting in poor durability.

Therefore, from the viewpoint of filtration efficiency and durability, the mesh spacing should be set to 5~
It is necessary to set it in the range of 50III.

The cross-sectional shape of the resin filament that constitutes the network is a polygon whose cross section is more than a square, or an ellipse with a flatness of 1.2 to 3. In the case of an ellipse, the flatness is defined as the ratio a/b of the short axis to the long axis a. If the flatness is less than 1.2, the cross-sectional shape approaches a circle, resulting in bonding only at the contact points, which is unfavorable from the viewpoint of adhesive strength. Also,
If this flatness exceeds 3, it is advantageous for joining, but it becomes weak against one bending deflection, so it is not preferable in terms of strength.On the other hand, in the case of polygons larger than quadrangles, especially rectangles, the joining part is a plane. However, a rectangular shape is weaker than an ellipse in terms of 2-bending deformation, and an ellipse is preferred in terms of durability.

The thickness of the mesh portion is preferably about 10.3 to 31,
If it is less than 0.3 mm, it will be easily bent and workability will be poor when loading it into a self-cleaning porous drum type filtration device.

On the other hand, if it exceeds 3m, it will be difficult to deform and, conversely, difficult to load. The above synthetic resin net 5 may be manufactured by either knitting or molding, but it is preferable that the intersecting portions of the vertical and horizontal directions are fused or bonded. Since the intersecting portions are fixed, they are less susceptible to deformation during operation of the filter, that is, during filtration or backwashing, resulting in improved durability.

(Function) In the case of a raised fabric made of ultrafine fibers with a single yarn fineness of 0.5 denier or less in the raised portion, when loaded into a self-cleaning perforated drum filtration device as a filter cloth, the fineness is small, so the direction of the fluff is changed by the water flow. changes easily, and this change in the direction of the fluff improves the cleaning effect, which in turn shortens the cleaning time.
This leads to improved durability of the filter cloth. Furthermore, the threads that make up this raised part are different from normal threads in terms of collection efficiency and are good in terms of performance, but since the fabric itself is flexible, it has poor shape retention. inferior to The filtration device can be loaded smoothly, the filtration device can be operated smoothly, the filtration efficiency is good, and the backwashing time can be shortened by laminating synthetic resin nets. This can only be achieved by On this occasion,
Regarding the adhesion between the net and the fabric, it can be achieved by specifying the shape and dimensions of the net and the resin filaments constituting the net, and satisfactory filtration efficiency and durability can be obtained.

(Example) The present invention will be explained below with reference to examples.

Example 1 Polyester filament 75 d / 68 f for warp
False twisted filament yarn, ultra-fine polyester filament 10d/336f for weft (single yarn fineness 0.3d
), double-sided weft 5-ply satin fabric [grey density: number of warp threads: 110/2.54C11, number of weft threads: 164/
After scouring 2.54cm), using a hydraulic napping machine, cloth 1
Raising was performed 7 times on the front side and 4 times on the back side at 5 m/min to obtain a raised fabric. The fabric weight of the obtained raised fabric is 215g/m”
Met.

Next, on the back side with low nap density, we applied a medium-low pressure polyethylene hard net [Product name: Trical Net N-28゜Takiron ■ product, mesh spacing 25 cranes, cross-sectional shape: ellipse, flatness 1
．． 5] were bonded together using an ultrasonic fusion method. The bonding conditions were a Pinsonic machine made by James Hunter,
Fusion processing was performed at a cloth speed of 1.5 m/min and an output cuff of 00 W.

The obtained filter cloth was attached to the inside of a self-cleaning porous drum type filtration device so that the polyethylene net was in contact with the drum. When the raw water moves from the inside of the drum to the outside from the surface with high density of piloerection to the back side, suspended solids, sand grains, etc.
It can remove dust, etc., and a water flow test was conducted using wastewater from a pulp and waste paper manufacturing factory as the raw water. In addition,
Although the SS component content of the raw water differed depending on the measurement time, the SS measurement of the raw water and treated water was performed every hour to sample over time, and the filter cloth of the example was tested a total of 4 times. Ta. The results are shown in Table 1.

As is clear from the table, the SS content of SS components (particle size of 5μ or more) in raw water can be largely removed by using the filter cloth of the present invention, and can be removed without using a flocculant. It showed excellent performance.

In addition, even after conducting this continuous water flow test for one week, no deformation or damage to the filter cloth was observed, and the filter material accumulated on the filter cloth could be removed with a small amount of washing water, making it highly durable. It was something.

(Effects of the Invention) According to the present invention, by using a raised fabric made of ultra-fine fibers, the collection efficiency is improved and the direction of the fluff is easily reversed by the water flow when washing the filter (because it is washed It can be expected to improve efficiency, and by forming a laminate with synthetic resin nets bonded together, it can be widely used as a filter cloth.

Patent applicant: Uni-Tei Riki Co., Ltd.

Claims (2)

[Claims] (1) The warp consists of false twisted yarn with a total fineness of 50 to 300 denier and a single yarn fineness of 1 to 8 denier, and the weft consists of ultrafine fiber filament yarn with a total fineness of 50 to 300 denier and a single yarn fineness of 0.5 denier or less. The raised fabric and the back side of the raised fabric have a mesh structure, and the cross-sectional shape of the resin filament forming the mesh is a polygon of square or more, or the flatness is 1.2 to 1.2.
A filter cloth formed by joining a synthetic resin net consisting of 3 ellipses and having a mesh interval of 5 mm to 50 mm. (2) The filter cloth according to claim 1, wherein the raised fabric is made of double-sided weft fabric.