JPS6345849B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention has improved overspeed and overcapacity, avoids the occurrence of undesirable clogging, and exhibits the effect of preventing deformation of the liquid passage gap, resulting in improved solidity.
The present invention relates to a pressurized or vacuum wet filtration method and cloth that exhibit liquid separation ability and durability and enable the formation of a cake with reduced moisture content. More specifically, the present invention relates to a surface having diagonal lines (twill) of a cloth made of a diagonal weave fabric in which a helical yarn is used as the weft yarn and untwisted continuous filament yarn is used as all or a part of the warp yarn. A pressurized or reduced pressure wet filtration method characterized in that the side is brought into direct contact with the liquid to be filtrated, and the pressure on the back side is relatively reduced than the pressure on the front side to filtrate the liquid to be filtrated, and its implementation. Concerning cloth suitable for use. Conventionally, solid-liquid separation using cloth has been widely practiced, for example, in pressurized wet filtration methods such as filter presses, pressurized leaf filtration machines, band presses, etc., or in Oliver In continuous rotary drum type vacuum filtration machines such as filters, horizontal rotary vacuum filtration machines such as pan filters and teller filters, reduced pressure wet filtration systems such as Moor leaf filtration machines, American desk filters, and band filters, cloth is used for processing. Pressure or vacuum wet filtration methods are used. Furthermore, various proposals have been made regarding the structure of cloth. However, each has its advantages and disadvantages,
A structure that has various properties such as excellent overspeed, excellent overcapacity, excellent clogging prevention properties, and deformation prevention properties of the liquid passage gap, as well as excellent solid-liquid separation performance and satisfactory durability. It has been difficult to provide simple fabrics, and it has been desired to provide improved fabrics and methods. The present inventor has studied various factors of cloth that affect solid-liquid separation performance, and in particular,
Although the passage of liquid through the fabric appears to be linear at first glance, it is actually non-linear and depends on the threads that make up the fabric, the fibers that make up the threads, their twisted state, and the woven structure. Therefore, we focused on this complex change and proceeded with the development of a cloth that combines the above-mentioned properties. As a result, the main factor that forms a non-linear path for liquid to pass through the fabric is yarn strands aparture, and the secondary factor is fider strands aparture and the woven structure. Control of bond parameters
It was discovered that this has a significant impact on the combination of the various performances mentioned above. As a result of further research, it was found that a woven fabric consisting of helical threads as the weft threads, non-twisted continuous filament threads as all or part of the warp threads, and a weave structure of a diagonal weave, preferably a herringbone weave. The helical yarn and the non-woven yarn are brought into direct contact with the liquid to be passed through, and the liquid is moved along the recesses in the diagonal direction between the diagonal lines. It has been discovered that by allowing the fabric to pass through the fabric via a path mainly through inter-yarn gaps formed by twisted continuous filament yarns, it is possible to achieve a fabric that combines the above-mentioned properties. Accordingly, an object of the present invention is to provide a cloth and a method of woven cloth that have all of the above-mentioned properties. The above objects and many other objects and advantages of the present invention will become more apparent from the following description. According to the present invention, the fabric is made of a diagonal weave fabric in which the helical yarn is the weft yarn and untwisted continuous filament yarn is all or a part of the warp yarn, and the surface side thereof has diagonal lines (twill). It is possible to provide a cloth in which the contact surface with the permeable liquid is made of The front side of the cloth made of such a diagonal weave fabric with diagonal lines (twill) is brought into direct contact with the liquid to be passed through, and the pressure on the back side is relatively reduced compared to the pressure on the front side. By passing the liquid through the liquid, it has various properties such as excellent overspeed, excellent overcapacity, excellent clogging prevention, and prevention of deformation of the liquid passage gap, and has excellent solid-liquid separation performance. It can exhibit satisfactory durability. In the present invention, the fabric structure is twill weave.
weave) organization. Among the oblique weaves, herring-bone twill is preferred.
There are two types of oblique weave: single-sided oblique weave (for 3 or more twills) and double-sided oblique weave (for 4 or more twills), but in the present invention, any type of oblique weave can be used. In the case of a double-sided diagonal pattern, since the woven fabric has diagonal lines (twill) on both sides, it does not matter which surface is used as the contact surface with the liquid to be passed through. Also,
When looking at the woven fabric in the warp direction, it can be either a left twill, in which diagonal lines run from the lower right to the upper left, or a right twill, in which the diagonal lines run from the lower left to the upper right.
Figure 1-A of the attached drawings is a tissue diagram (front side) of an example of the fabric of the present invention having diagonal lines on one side (three twills), and Figure 1-B shows the organization chart (front side) of an example of the fabric of the present invention having diagonal lines on one side. This is a schematic diagram seen from the side. Further, Fig. 2-A is a tissue diagram (front side) of an example of the fabric of the present invention with a double-sided diagonal pattern (four twills), and Fig. 2-B is a schematic diagram as seen from the upper side. Furthermore, Figure 3-A is a tissue chart (the front side, in this example, the same is true for the back side) of an example of the present invention fabric with herringbone double-sided diagonal pattern (four-twill pattern), and Figure 3-B is the organization chart of the same. It is a schematic diagram seen from the top side. In the organization chart above, the shaded area is the area where the weft yarn (heilly wound yarn) is exposed on the front side, and the non-shaded area is the area where the warp yarn is exposed on the front side. . In addition, in the example illustrated above, the helical yarn is the weft yarn, and the warp yarn is entirely composed of untwisted continuous monofilament yarn, but the untwisted continuous filament yarn is a monofilament yarn. It may be a yarn, a multifilament yarn, or an appropriate combination thereof. In the above-mentioned organization chart 1-A, the portion composed of the untwisted continuous monofilament yarns 1, 2, 3 and the helical yarn is the unit structure portion of the triple twill. In the above organizational chart 2-A, untwisted continuous monofilament yarns 1, 2, 3,
4 and the helical thread, . . . are the 4-ply twill unit structure. Also, 3-
In the case of the herringbone double-sided diagonal pattern in figure A, the illustrated part is the unit structure. In the present invention, in addition to satisfying the structure requirements of a woven fabric having a diagonal weave structure as described above, a weft yarn in which a spiral yarn is used as the weft yarn and untwisted continuous filament yarn is used as the whole or part of the warp yarn is used. and warp requirements must be met. The core yarn of the helical yarn is preferably a mono- or multi-filament continuous filament yarn of synthetic fiber, particularly preferably an untwisted continuous filament yarn. The sheath yarn of the helical yarn is also preferably a synthetic mono or multi-continuous filament yarn,
More preferably, it is a non-twisted continuous filament yarn. Examples of the synthetic fibers to be used include filament threads of synthetic resins such as polyethylene, polypropylene, polyester, polyamide, and polyvinylidene chloride. If desired, synthetic fibers and natural fibers can be used in combination. As the untwisted continuous filament yarn used for the warp, mono or multi-filament yarns made of synthetic resin as exemplified above can be exemplified. The warp yarns may be entirely composed of untwisted continuous filament yarns, or may be partially composed of such filament yarns. In this case, it is inappropriate for the filament yarns to be arranged unevenly in only a part of the width direction of the cloth, but one or more filament yarns should be arranged at appropriate intervals between other warp yarns. It is better to do so. The above interval is, for example,
Preferably, the spacing is about 1 cm to about 10 cm.
The other warp yarns can be twisted yarns,
It may be either S twist or Z twist, or a combination thereof. When used in combination, the S-twisted yarn and the Z-twisted yarn can be alternately arranged in various manners as disclosed in JP-A-49-32266, for example. In the present invention, the combination of the above-mentioned properties of the cloth made of the diagonal weave fabric configured as described above is achieved by the weaving structure requirements, that is, the diagonal direction recesses between the diagonal lines (twill) on the side surface. The presence of grooves, the gaps between weaving yarns formed by the above-mentioned weft yarns made of the helical yarns, and the warp yarns made of the above-mentioned untwisted continuous filament yarns, and the gaps between the fibers constituting the weaving yarns, especially due to the helical yarns. This results from the cooperative effect of the coupling parameters with the liquid path formation requirements consisting of interfiber gaps. For example, as shown in the above example, when a part of the warp is composed of untwisted continuous filament yarn and other warp yarns are S-twisted and Z-twisted yarns, the untwisted continuous filament yarn is omitted. If the warp yarns are made of two types, S-twist and Z-twist, overspeed and overcapacity will not only worsen, but also have a negative effect on the prevention of clogging, the prevention of deformation of the liquid passage gap, and the durability. The improvement objective of the invention will no longer be achieved. Furthermore, for example, if the weft is made of an untwisted continuous filament yarn instead of a spirally wound weft, it becomes difficult to separate fine solids, and it is also difficult to avoid deterioration of the various properties described above. Furthermore, even if the liquid path formation requirements of the specific warp and weft yarns of the present invention are satisfied, if the weaving structure requirements are not satisfied, it becomes difficult to achieve both of the above properties. It is preferable that the helical thread constituting the weft has a denier of, for example, about 700 to about 2000 deniers, and the untwisted continuous filament yarn constituting the warp has a denier of about 400 to about 900. Of course, as long as the combination parameters of the weave structure requirements and liquid path formation requirements are satisfied, changes can be made as appropriate. According to the present invention, the front side of the cloth having diagonal lines (twill) as described above is brought into direct contact with the liquid to be passed through, and the pressure on the back side is relatively reduced than the pressure on the front side. , it has all the above-mentioned excellent properties and can perform wet filtration of the filtrate with high efficiency. Hereinafter, one embodiment of the fabric and method of the present invention will be illustrated in more detail with reference to Examples. Example 1 and Comparative Example 1 Inventive fabric: - Warp: 2000 denier polypropylene monofilament and 400 denier 3-strand (Z) polypropylene multifilament, the former being the latter
Weft threads arranged at intervals (approximately 5 cm) at a ratio of 1 per 10 threads: 400 denier 3-strand untwisted polypropylene multifilament as core yarn, 48 filament as sheath yarn, 400 denier polypropylene Spiral thread made of multifilaments. A herringbone double-sided diagonal fabric made of the warp and weft yarns mentioned above. Comparative fabric: - A herringbone double-sided diagonal pattern fabric similar to Example 1 above, except that the warp yarns were composed only of 400 denier three-strand (Z) polypropylene multifilament. The fabric of Example 1 and the fabric of Comparative Example 1 were each subjected to the same filter press type pressurized wet filtration machine to carry out the same coagulant-added industrial wastewater overload test. The results are shown in Table 1 below. The amount of liquid at the start of the test (the amount of liquid that came out after being separated from the solid content) was as follows: Example 1 cloth and Comparative example 1
500 per square meter of cloth in either case
It was hot. The decrease rate (%) of the above liquid volume after 1 month, 2 months and 3 months is calculated as follows:
It is shown in the table.

[Table] After the above 3-month test, changes in yarn strands aparture for each fabric were observed using a microscope using a combination of transmitted light and reflected light. Although the change was slight, a large change was observed in the cloth of Comparative Example 1.

[Brief explanation of the drawing]

Attached drawings Figure 1-A is an organization chart showing an example of the fabric of the present invention, Figure 1-B is a schematic view of the cloth as viewed from the side, and Figures 2-A and 2-B are other examples. 3-A and 3-B are similar diagrams of yet another example.

Claims (1)

[Scope of Claims] 1. A surface having diagonal lines (twill) of a cloth made of a diagonal weave fabric in which a helical yarn is used as the weft yarn and untwisted continuous filament yarn is used as all or a part of the warp yarn. A pressurized or reduced-pressure wet filtration method characterized in that the side of the filtrate is brought into direct contact with the liquid to be filtrated, and the pressure on the back side is relatively reduced than the pressure on the front side to filtrate the liquid to be filtrated. 2. The method according to claim 1, wherein the helical yarn is a helical yarn whose core yarn is an untwisted continuous filament yarn. 3. The method according to claim 1 or 2, wherein the sheath yarn of the helical yarn is a non-twisted continuous filament yarn. 4. The method according to any one of claims 1 to 3, wherein the woven fabric is a herringbone woven fabric. 5. Consists of a diagonal weave fabric in which the helical yarn is the weft yarn and untwisted continuous filament yarn is all or a part of the warp yarn, and the surface side with diagonal lines (twill) is the liquid to be passed through. Pressure or vacuum wet cloth used as contact surface.