JPH08150309A - Filtration bag made of single layer net of non-adhesive synthetic resin monofilament yarn fabric and filter using the same - Google Patents

Abstract

PURPOSE: To conduct stabilized high-precision filtration and to realize filtration excellent in economy and operability by forming the filtration bag consisting of plain or twill fabric of a highly non-adhesive synthetic resin monofilament yarn. CONSTITUTION: This filter is useful to produce city water, etc. This filtration bag as the filter bed especially of a continuous flocculating, filtering separation tank is formed by sewing a single layer net of plain fabric having about 40μm meshes with the monofilament yarn of non-adhesive synthetic resin PFA as a weaving thread obtained by impregnating a glass thread with PTFE and baking the impregnated thread. When raw water is filtered, aluminum polychloride, sodium polyacrylate, etc., are added, and rapid agitation and then slow agitation are applied to impart a pressure increase equivalent to the weight of the injected flocculated raw water. Consequently, the flocculated raw water in the bag is discharged outside the bag from the filtration hole of the texture, and continuous filtration is performed without being interrupted due to the clogging of the filtration hole.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter device. More specifically, the present invention relates to a novel filtration device that is useful for producing clean water, etc., which enables continuous filtration of porosity fluid such as water without blocking pores.

[0002]

[Prior art and its problems]

(Current situation of water supply production and its problems) Purification of water, including the production of water supply, has been performed mainly by gentle and rapid sand filtration. In the future, there will be a better purification method that can replace this method. It was even said that it would not appear.

However, due to the diversification and increase in the amount of domestic waste brought about by the rapid improvement of living standards in recent years, it has been found that effective improvement measures can be taken to contaminate the water source of tap water and cope with it. The voices saying, "I can't drink tap water" are now growing, even though they cannot be issued. For this reason, the water supply industry has a higher purification capacity than conventional sand filtration, does not require a vast area, is easy to install, and has a filter bed with a closed bed. There is a strong demand for the realization of a new purification method that eliminates the disadvantages of the conventional sand filtration methods such as easy recovery.

[0004] Such a situation is not limited to the field of water supply production, but is widely used in various water treatment fields such as the recycling of domestic wastewater and the purification of industrial and domestic wastewater for discharge into rivers and lakes. This is also the case in Japan, and it is an urgent issue from the viewpoint of effective use of water resources around the city, where the shortage is becoming more serious, and environmental conservation, where global measures are required. (Actual condition of sand filtration method) In sand filtration, which is currently the basic method for producing clean water, fine solid particles suspended in the raw water to be filtered are separated from each other by much larger particles than filter particles. The gap is filtered as a filter hole. The relational dimension between the suspended particles and the gap between the filter media particles is also shown in the schematic diagram of KIIves, but the suspended particles whose size is at most several tens of microns, and even more than that. The reason why the fine colloidal particles can be separated and suppressed by the much larger large interstitial filter pores of 100 μm to 200 μm is considered as follows.

That is, the solid fine particles / colloidal particles suspended in the raw water to be filtered are transported to the surface of the filter medium by the action of transport process factors such as: sieving action, Brownian motion, water flow function, inertial collision, and precipitation. ,
The solid particles having a particle size larger than the gaps between the filter media particles are caught on the filter media surface in a clogged manner by the sieving action. Further, inside the filter bed, clogging is trapped between the filter media particles due to the blocking action. These captures separate the particles from the filtered water. The fine solid particles whose particle size is smaller than the gap between the filter media particles are the interfacial electrochemical interaction due to the interfacial conditions between the surface of the suspended fine particles and the surface of the filter media particles or the particles that have been pre-deposited on them. If the adhesion conditions such as chemical cross-linking and adsorption are satisfied, the suspended fine particles adhere to the surface of the filter media particles or the fine particles that have been previously adhered to the filter media and are separated from the filtered water by this capture. To be done.

However, the above-mentioned adhesion occurs only when the interfacial conditions between both particles are suitable for adhesion. If this is not the case, the transported particles are not adhered again and are re-adhered. It will be returned to the suspension system. Further, particle attachment occurs mechanically or by biological action, but the proportion thereof is only slight.

(Problems of sand filtration) As can be seen from the actual conditions of sand filtration described above, sand filtration is an internal filtration (inn
er filtration), that is, the suspended particles are attached to the surface of the filter material particles inside the filter bed to be captured, and separated from the filtered water to obtain fine suspended particles having a particle size of 1 μm or less,
It has the advantage that it has a microfiltration capability that can remove even colloidal particles.

However, such an advantage is exerted only when the interfacial conditions between the suspended particles and the filter media particles are suitable for adhesion, and when these conditions are not suitable. Is mixed with the filtered water and flows out of the filter bed without adhering. Moreover, if the particle size is smaller than 100 to 200 μm, the particle size is 100 μm.
Even coarse particles as large as m may flow out without being suppressed, which is a factor that seriously impairs filtration accuracy.

In fact, in many cases, the filtered water is discarded as it is without being used as clean water at the beginning of sand filtration. The reason for this is thought to be insufficient biological purification during the absence of biofilm formation, but essentially, the coarse particle entrapment leak during the incomplete progress of internal filtration and the accuracy of the escape due to the escape. I must say that the main cause is badness. Moreover, such a thing is not limited to only the initial stage of the filtration, and even in the middle and late stages of the filtration, as long as the gaps between the filter media having the pore diameters exceeding the target accuracy remain, the trapping and escape of coarse particles can also occur. Continuing, it becomes a cause of poor accuracy.

As described above, the sand filtration greatly contributes to the refinement of the filtration by its internal filtration, but at the same time, since it is a huge filtration hole, coarse particles exceeding the target accuracy are left in the filtration water, and the filtration water as a whole is filtered. However, it also has a drawback in that it cannot have the filtration accuracy required for tap water. Therefore, the filtration accuracy by sand filtration is unexpectedly poor, and a large amount of solid matter still remains in the filtered water, resulting in SS, turbidity, CO
Numerical values such as D and BOD are deteriorated, and the eluents from these residual pollutant substances further promote water pollution. This is a factor that further accelerates pollution through the diversification and mass increase of social pollutant sources due to the improvement of living standards, and eventually leads to the situation that "the water in the tap water cannot be drunk". To be done. (Issues to be solved by sand filtration and single mesh filtration as an improvement measure) As described above, sand filtration is not as reliable as it has been believed so far.

The most important problem is that the large pore size filter pores, which depend on the internal filtration of the sand filter, cause the trapped escape of the coarse suspended particles, and the accuracy of the filtration is remarkably unstable. That is to say coarse filtration. And this is not limited to sand filtration, but granular bed filtration,
This is a drawback common to depth type filtration, which depends on internal filtration for its filtering accuracy, such as porous layer filtration.

In order to solve the problem of the depth type filtration such as sand filtration in which the escape of coarse particles is unavoidable and the recovery of the pores when it is blocked is difficult, the internal filtration is performed as described above. Eliminating dependence on is the most necessary. As a solution to such a problem, the present inventors have already developed and proposed a microfiltration method using a single plain weave metal precision mesh.

In this filtration, in the case of sand filtration, the depth of the gap between the filter media, that is, the depth of the filter pores is made as close to zero as possible, and the suspended fine particles in the filter bed due to adhesion, clogging, etc. The opportunity and necessity of trapping (internal filtration) were eliminated, and on the other side, the filter pore size was made as small as possible to maintain the value within the target filtration accuracy, and all coarse particles exceeding that accuracy were checked on the front surface of the filter bed. The trapping is sequestered and separated so that the escape and contamination of the filtered water can be completely prevented.

The solid fine particles and colloidal particles having a particle size smaller than the mesh size, which cannot be suppressed by the precision of this precision filter mesh, are flocculated and flocculated, and the flocs are subjected to a treatment such as sedimentation / floating filtration. By separating and separating this separately before filtration, all solid matters can be completely separated and removed. In addition, in this metal mesh filtration, the mesh of the metal mesh can be plated to refine it to the target value of microfiltration, that is, to the micron numerical level of one digit, and the depth of the filter hole is almost zero. Due to this structural feature, the filtration pressure is low, and the strength of the mesh can sufficiently withstand this filtration pressure. This is
Patent No. 1377636 (Japanese Patent Publication No. 61-44527)
It is also shown in.

Further, in the case of sand filtration, it has been a major problem to eliminate clogging, to secure and maintain stable filtration accuracy, and to easily recover the blocked filter bed. However, such a problem can be completely improved in the single plain weave metal net filtration. That is, in this single-layer plain weave metal mesh filtration, in which the dependence on internal filtration was eliminated and the concern about precision instability was resolved, it is the size of the inner diameter of the filter hole that determines the filtration accuracy of the filter bed. , It is an opening of eyes, but it is extremely easy in terms of its structure in this filter bed that is a single flat-woven metal net to eliminate the variation in the filter pore size and stabilize and make it uniform.
This is because it is sufficiently possible to keep the filter pore size within the target accuracy range and within the variation range of about 10%.

Further, as shown in the above-mentioned Japanese Patent No. 1377636, in the mesh filter hole of a single plain weave metal mesh, the cross-sectional area is the narrowest in the central part, and the front and rear (filtering) The inlet part where the raw water flows in and the outlet part where the filtered water flows out) gradually expands toward the end. During filtration, suspended solid particles having a particle size larger than the narrowest cross section are blocked from flowing in at the narrowest cross section, and are blocked by the sieving action in front of the front of the filter bed. On the other hand, solid particles whose particle size is the same as or smaller than the narrowest cross section,
Although it does not block the inflow, it flows into the narrowest cross-section, but since it has no depth, it cannot stay in the narrowest cross-section for a while, and immediately flows out and is discharged to the outside of the mesh filter holes. Therefore, in the case of this single plain weave metal net filtration, clogging cannot occur.

Further, in the case of sand filtration, clogging is the main cause of clogging of the pores, and once the pores are clogged, recovery is not easy, and a great deal of labor and time is required for backwashing and washing. However, there are some things that are inefficient and uneconomical, but in this single plain weave metal net filtration, as described in, for example, JP-A-64-7918, only a simple switch operation is required. The backwashing for a few tens of seconds completely restores the blockage of the filter pores and allows subsequent continuous filtration. (Single plain weave metal net filtration that can be used for water supply production that improves sand filtration) As described above, single plain weave metal net filtration overcomes all the problems of sand filtration to date. It was possible. In particular, the filtration device described in JP-A-64-7918, which performs agglomeration in advance, enables the recovery by backwashing during the time when the filter hole is closed, in terms of the quality of the produced water, and It is a new filtration device that can be used as it is for the production of tap water because it can be continuously and continuously filtered. (Another improvement measure for sand filtration, single mesh filtration of synthetic resin monofilament yarn plain weave) As described above, a single plain weave metal mesh filtration is a filtration method capable of improving the disadvantages of conventional sand filtration. It has been described in detail that the filter device of Sho 64-7918 is a filter device that can be used as it is for the production of clean water. For example, "Filtration and filter aids" (Taiji Sugimoto, Jijishokan) Issue), "The filter mesh is also made from plastic monofilaments."
"Since the monofilament woven fabric creates a simple void just like a wire mesh, it has less clogging, is better at removing the cake after filtration, and is easy to wash." As described above, the plain weave fabric of the synthetic resin monofilament yarn is a filter mesh rather than a filter cloth, and the filtering function thereof is exactly the same as that of the metal plain weave filter mesh. Therefore, if the single filter mesh is used as a filter bed, the material is changed from a metal to a synthetic resin, the synthetic resin mesh filter bed is used, and it can also be used for producing water.
The filtering device is established. That is, a filter bed composed of a single mesh of synthetic resin monofilament yarn plain weave can be another improved filter bed for sand filtration along with a single precision mesh mesh of plain weave metal. However, the point to be noted in this case is that metal and synthetic resin as net materials are
There is a difference in strength, the former is said to be the same low viscosity fluid,
While it is possible to filter fluids with higher viscosities, the latter is limited to the filtration of fluids with the lowest viscosity class such as water, so it is possible to deal with slight differences in physical properties between the two materials. It is necessary. (Improvement to a filtration device for the production of clean water by using a single hand-woven net (made of metal and synthetic resin) that can also be used for the manufacture of clean water)
However, a single plain weave mesh filtration (made of metal and synthetic resin), especially Japanese Patent Laid-Open No. 64-791, which is preceded by an aggregating step.
The filtration device of No. 8 is a water treatment device that can overcome the problems of sand filtration up to now and can be sufficiently used for producing clean water.
If this is evaluated only for water supply production, it cannot be said that it is necessarily the optimum filtration device for water supply production.

This is because, for the filtration device of Japanese Patent Laid-Open No. 64-7918, which has a treatment target of several hundreds of cubic meters per day, a treatment of several hundreds of thousands of cubic meters per day is required. This is because the usual amount of clean water production far exceeds its capacity. It is a huge amount of processing, and in order to enable this processing, it is possible to build a large capacity processing device for it.
Moreover, it is necessary to change to a simple and efficient structure that can be easily operated and operated. Specifically, while maintaining the filtering function of single-layer plain weave mesh filtration (made of metal and synthetic resin) as it is, it has a non-sealed structure open to the atmosphere similar to the conventional sand filtration device, This is a new structure that enables low gravity filtration without pressurization, and does not require the operation itself to recover the blockage of the filter hole, that is, new filter hole non-blocking, filtration non-stop, and continuous filtration.

[0019]

The present invention has been made to solve the above problems, and is a monofilament yarn weave plain weave or twill weave single filter mesh of highly non-adhesive synthetic resin. The present invention also provides a filtration bag formed by molding, and also provides a low-gravity pressure filtration device including a non-sealing type filtration tank, which has a filter bed built-in, and is provided with an inlet passage for a fluid to be filtered and a drainage passage for slag. It is a thing.

The structure, function, and operational points will be described in detail below. (Non-adhesive Synthetic Resin Monofilament Yarn Woven Plain Woven Single Filter Net Filter Bag) Japanese Patent Laid-Open No. 64-791
The No. 8 filter (made of metal and synthetic resin) recovers the blockage of the filter pores in a short time by backwashing and enables continuous filtration continuously. It can also be useful for tap water production. It could be used as a static sand filter, but on the other hand, in order to make backwashing effective, it was forced to have a closed structure. For this reason, there are aspects that cannot be structurally applied to large-capacity treatment that requires an open structure, such as water supply production. As mentioned above, the factors that block the filter holes include internal filtration factors such as clogging and adhesion,
There are three blockages on the front surface of the filter bed, and in the single-layer plain weave mesh filtration, there is no internal filtration factor, and the blockage of the filter pores is only the blockage, so that it can be easily recovered by backwashing. However, when the closed structure becomes impossible due to the large capacity treatment, it is not necessary to recover the blockage of the filter hole, in other words, it is unavoidable to rely on a filtration method in which the filter hole is not closed. . Therefore, in the present invention, in a filter bed of a single plain weave filter screen made of synthetic resin, clogging / adhesion cannot occur, and the only factor of filter hole blockage is clogging of the front surface of the filter bed. The resin is a non-stick synthetic resin such as PTEE
(Tetrafluoroethylene resin). In this way, during filtration, even if coarse solid particles larger than the mesh pores float at the plugging position and temporarily block the pores, they will stick to the non-adhesive yarn surface and stick to them. There is nothing to do. Therefore, due to the action of gravity, water flow, etc., the position is changed at a short time and the mesh filter hole is opened again for passage of the filter water, and the filtration is continued without interruption. That is, in a filtration tank containing a non-adhesive synthetic resin monofilament yarn woven plain weave single filter mesh filter bag as a filter bed, it was possible to achieve both a non-sealing open type structure and a filtration non-stop continuous filtration, An unprecedented new and efficient filtration device for producing water will be realized. (Non-adhesive Synthetic Resin as Material for Filter Net) The non-adhesive synthetic resin that can be used as the material for the filter bag of the present invention is preferably PTEE (tetrafluoroethylene resin), PFA (tetrafluoroethylene-peroxide). Fluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene-hexafluoropropylene copolymer resin) and the like. For reference, Table 1 shows characteristics of various resins. Of these, PFA and FEP, which are currently used as monofilament yarns in woven yarns for filter mesh, can be easily made into monofilament yarns by melt spinning. Therefore, at present, the non-adhesive synthetic resin as the material for the filter bag of the present invention is P
It is easily configured by two of FA and FEP. These fluororesins are excellent in heat resistance, weather resistance, and chemical resistance, have almost no elution from themselves during filtration, and are extremely excellent materials for filter media from the viewpoint of filter media.

[0021]

[Table 1]

(Current filtration accuracy of non-adhesive synthetic resin monofilament / yarn woven plain weave filter mesh and its application field) Up to now, only the precision of filtration has been aimed at, and the high filtration pressure and high pressure resistance associated therewith The difficulty of recovery of the filter, such as the difficulty of recovery when the filter hole is clogged, the difficulty in the operation of the device, the efficiency of operation, the economical efficiency, etc. have not been taken into consideration. Originally, in the field of metal mesh filter media, only sintered metal powder filter media, fiber filter media, laminated filter media, etc., which are expected to have a distribution of fine voids for precision filtration, are considered important, and a single plain weave Metallic netting has only been considered as a coarse filter material for strainer filtration. Similarly, also in the field of synthetic resin mesh filter media, between the fibers constituting the felt / nonwoven fabric and its spun yarn for the purpose of utilizing the fine inter-fiber voids as precision filtration holes. Only multi-filament yarn woven filter cloth, which can utilize fine voids as precision filter holes, has been exclusively used.
Filament yarn, plain weave, or twill weave mesh has never been considered as a filter medium for microfiltration. Therefore, in the present situation, the mesh opening of the non-adhesive synthetic resin mono / filament / yarn woven plain weave filter mesh of the present invention is 180 μm in the most precise manner. Is considered to be limited to an accuracy of 40 to 50 μm. Therefore, for the time being, in the field of application of the present invention, the limitation of the range of coarse filtration with an accuracy of 40 μm or more is inevitable. Therefore, 40μ
The present invention is not suitable for microfiltration of m or less at present. However, regardless of the accuracy, the following features are taken into consideration in order to utilize and utilize the feature of the present invention, that is, filtration without pore blockage. It can be used very effectively in the field.

For example, in the filtration prior to the subsequent operation, if solid particles having a particle size of 40 μm or more are continuously separated and removed without interruption of the filter pores, the final accuracy is maintained. In some cases, it may be enough if left to field operations. For example, solid-liquid separation filtration for the purpose of removing solids in the septic tank of the septic tank, solid-liquid separation filtration for removing coarse solid particles prior to the coagulation treatment, and the like. In addition, solid matter having a size of the precision (for example, 40 μm) or more has been completely removed by the pre-filtration, and in the case where the remaining total solid matter can be completely separated and removed by the filtration, for example, agglomerated. Coagulation / separation filtration for removing flocs, or low-viscosity fluid having a viscosity close to that of water other than water, for example, circulation / reuse filtration of engine oil or the like of power vehicles.

By combining the above-mentioned pre-filtration for coagulation treatment and separation / filtration for coagulation floc removal, it is possible to completely separate and remove all solids (including colloid particles) in raw water, thereby producing clean water. Micro filtration for use becomes possible. Needless to say, the present invention is also applicable to openings with a higher precision than 40 μm, which is technically expected. (Required filtration pressure for filtration by the filtration bag of the present invention) In the filtration bag of the present invention and the filtration device using the same,
The required filtration pressure is extremely low, and gravity-type low filtration pressure in a natural state is possible without requiring additional pressurization. The reason will be described in detail below.

FIG. 1 is a partially enlarged plan view of a plain weave single filter net according to the present invention, and FIG. 2 (a) (b) (c).
[Fig. 6] is a partial cross-sectional view taken along aa 'and bb'. In FIG. 2C, the reference numerals indicate the following. d: Filter pore diameter r: Filter pore radius s: Filter bed thickness i: Filter pore inlet part depth o: Filter pore outlet part depth Water flowing through the filter pores during filtration forms a laminar flow, and Hagen Poiseuille (Hagen poiseuille) rules. Therefore, the size of the filtration pressure required for this filtration is Hagen-Poiseuille type.

[0026]

[Equation 1]

Where p is the value of pressure loss P
Is obtained as the value of, or is estimated to be close to. The filter material to be used according to the present invention, the non-adhesive synthetic resin mono-filament yarn, the mesh filter pores of the single filter mesh of the plain weave, and the required filtering pressure for filtering water is estimated based on the Hagen-Poiseuille formula. As shown in FIG. 2 (c), the length l of the filter hole is as close to zero as possible, l≈0, and the viscosity η of water is various. Since it is the smallest in the fluid (Table 2), p
Other factors that influence the value of, q (flow velocity), and r (radius of filter hole, filtration accuracy) are expected to have some widths, but the value of p is basically extremely small. Is estimated. In fact, a synthetic resin mesh filter hole as a filter medium used in the present invention and a water-filling filter test by a single plain weave stainless steel mesh filter hole having an opening of 5 μm, which has similar pore-like structural functions, , Precision filtration with an accuracy of 5 μm
Considering that it was possible with a low filtration pressure of 0.05 kg / cm ² and a bottom pressure of 50 cm of submerged water, and that the material for filter media of the present invention has better slipperiness and non-adhesiveness than stainless steel. It is considered that the required filtration pressure is even lower than this, and it is estimated that the desired finest filtration, the filtration of the absolute laiting 5 μm, is sufficient with the bottom pressure of 50 μm of water.

[0028]

[Table 2]

According to the above, even in the practical stage, even when the bottom pressure of 3 and 1.5 m is prepared as the safety factor, the gravity type low filtration pressure in the natural state is the same as the conventional sand filtration. Therefore, it is concluded that filtration is sufficiently possible. Further, it has been experimentally confirmed that the mesh filter material used in the present invention can sufficiently withstand the pressure resistance against the low filtration pressure.

Further, as a filtration method capable of performing the non-blocking continuous filtration of the present invention most effectively, there is another type of filtration method which should be called "static / hydrodynamic Pascal pressure filtration". That is, in general filtration, the front surface of the filtration is kept in a flooded state with the raw water to be filtered and the back surface thereof is kept in an anhydrous state, and the filtration is performed by using the pressure difference between the front surface and the back surface of the filter hole as the filtration pressure.
In Pascal pressurization filtration, the filter hole front surface, that is, in the case of the present invention, is the raw water to be filtered, and the filter bag outside of the filter hole backside is the filtered water, both of which are placed in a submerged state. It passes through an orifice (Oridice), which has numerous mesh pores.
When the filtration is stopped after the filtration is stopped, there is no pressure difference between the front and back sides of the cloth, and as a single continuous still water mass that maintains the same level as the bottom level of the drainage pipe of the filtration tank. When the filtration is maintained and the progress of filtration, the raw water in the bag has a network of pores, with the Pascal principle increasing pressure that brings the raw water poured into the bag from the raw water tank to be filtered placed in the upper part of the bag as the substantial filtering pressure. It passes and moves out of the bag, and filtration is performed during this period. Large solids that cannot pass through the mesh orifice will remain in the bag and become cake. This filter residue is stored in a bag and continuously taken out without interruption while being taken out for any time. Such Pascal pressure filtration is possible by providing the filtered purified water from a considerably upper portion than the bottom portion, that is, by providing a purified water discharge pipe at a considerable upper portion. (Filtration by the filtration bag of the present invention under low gravity pressure opened to the atmosphere) As described above, the mesh of the single synthetic resin mono-filament yarn woven plain weave or twill weave mesh of the present invention As shown in FIG. 2 (c), the value of the depth l of the filter hole is 1≈0, which is almost zero. In addition to providing a rational filter hole with no clogging, the structural features that the depth length is also close to zero and the condition that the viscosity of the water to be filtered is minimal (Table 2) create a synergistic effect. The action of water is exerted and the filtration of water at an extremely low filtration pressure enables the filtration at a gravity type low filtration pressure in a natural state that does not require special pressurization opened to the atmosphere.

As described above, according to the filtration bag of the present invention,
A new filtration method that replaces the conventional sand filtration that is efficient and energy-saving is provided for the production of tap water. In addition to this,
Filtration of clean water by using the conventional clean water purification methods such as oil and fat removal treatment, disinfection, ozone treatment for decolorization / activation, activated carbon adsorption treatment for deodorization / decolorization, addition of the minimum necessary chlorine, etc. The equipment can be reborn as a groundbreaking, state-of-the-art, improved and water production equipment.

[0032]

EXAMPLES As an example of a gravity type low filtration pressure continuous filtration apparatus without filtration according to the present invention, in which a bag for filtration without blocking pores is used as a filter bed, coagulation which constitutes one step of household wastewater treatment The continuous filtration separation tank will be described. 3 (a) and 3 (b) are a plan view and a cross-sectional view illustrating a filtration bag incorporated as a filter bed in the flocculation continuous filtration separation tank.

That is, a single mesh of plain weave having an opening of 40 μm, which is woven by using monofilament yarn of non-adhesive synthetic resin PFA as a weaving yarn, is used as a glass twisting yarn with PTFE.
It is a non-adhesive high-strength sewing thread which is impregnated and baked, and is a bag for filtration which is sewn confidentially so as to completely prevent leakage of water from the stitched portion. No non-adhesive material that causes adhesion of filter residue is exposed inside. In other words, it is a bag that does not adhere to filter cake. The reference numerals in the figure indicate the side filtration surface (1), the bottom filtration surface (2), and the sheath tube (3) through which the bag support tube of the pedestal is mounted so as to hold the side filtration surface in a flat plate shape. 1 shows a stainless steel filter cake storage chamber (4) for storing sludge pumps for temporary storage of the filter cakes and intermittent withdrawal of the filter wastes during that time.

FIGS. 4 (a) and 4 (b) show a pedestal for supporting the filter bag and holding the bag body, which are made of stainless steel chevron girders, pipe pipe legs, pipe pipe bag support columns, and bolts. 3A and 3B are a plan view and a cross-sectional view illustrating a non-rusting movable structure having a simple structure assembled with a nut. The filtration bag is a pipe leg (1
In 1), it is installed on the bottom of the filtration separation tank (or septic tank in the case of a septic tank), and is fixed to the fixing girder of the wall of the filtration separation tank with bolts and nuts at the upper girder terminal fixing portion (12). The bag supporting column (13) supports the filter bag by penetrating the inside of the filter bag sheath cylinder and tightly binding it, and holds the filter bag side filter surface in a planar shape.

FIG. 5 shows a filter separation tank having a filter bag built therein, which is open to the atmosphere. It may have a lid,
The lid is dust-proof, does not need to be sealed, and can ventilate with the outside air. In FIG. 5, the filtration / separation tank body (100), the tank side wall (101), the bag outer cylinder wall (102) around the filtration bag, and the cylinder wall lower water passage port (103) are shown. The filtered water that has flowed out of the bag due to filtration is lowered through the cylindrical wall and its lower water passage port, and after being raised through the tank bottom, it is discharged from the filtered purified water discharge pipe (104), thereby filtering after filtration. Prevents the water from staying in its place, impeding the progress of filtration. Filtration bag fixing girder (1
05) is welded (bonded) to the tank wall, and the fixing surface projects outside the wall.

The raw water receiving tank (200) arranged above the filtration separation tank is open to the atmosphere. Receiving tank body (2
01) has a raw water injection pipe (202) that descends from the bottom of the receiving tank body and opens at the center of the bag. It also has a raw water supply pipe (300) to be filtered and a sludge discharge pipe (400), the lower end of which is connected to a sludge pump stored in the sludge storage chamber.

The coagulation filtration separation is started by pouring unfiltered flocculant-unseparated raw water (hereinafter referred to as coagulation raw water) into a raw water receiving tank. The coagulated raw water is obtained by adding 80 ppm of polyaluminum chloride (PAC) and 6 ppm of sodium polyacrylate (Panakayak CSG) to the raw water to be filtered, followed by rapid stirring for about 2 minutes and then slow stirring for 8 minutes. is there. The poured coagulated raw water causes a pressure increase corresponding to the weight of the poured coagulated raw water at each point inside the bag due to the Pascal principle of hydrostatics, and due to the pressure difference inside and outside the bag, the coagulation inside the bag is caused. Raw water passes through the textured filter holes and flows out of the bag, and filtration is performed in this process. Aggregated flocs cannot pass through the filter holes and are suppressed to form a filter residue that accumulates in the bag.The filtered purified water that has flowed out raises the outside level of the bag, and the portion that exceeds the bottom level of the filtered water discharge pipe is used as filtered water. It is released outside the tank. Thus, only by pouring coagulated raw water,
No other additional pressurization is required, and the filtration is continuously performed without interruption due to blockage of the filter holes. The filter cake captured and retained in the bag can be appropriately treated by another process without any trouble in the filtration by the temporary withdrawal of the filter.
Incineration, soil treatment in the ground, etc.

The large-capacity coagulation filtration separation tank for producing clean water has a large number of filtration cross-sections capable of accommodating this large-capacity filtration in a large-capacity separation tank main body corresponding to the required capacity. This can be easily constructed by incorporating the filtering bag groups in parallel. The operation is exactly the same regardless of the capacity. FIG. 6 shows a septic tank of a septic tank, which has a filter bag for solid-liquid separation without filter holes blocked. The structure and function are similar to those of the filtration separation tank of FIG. However, in order to prevent the accumulated scum from being directly exposed to the outside air and becoming scum, a filtering surface is also provided on the upper part of the bag, and by the filtered purified water,
Avoid direct contact between air and storage sludge.

[Brief description of drawings]

FIG. 1 is an enlarged plan view showing a plain weave state of a filter bag according to the present invention.

2A, 2B, and 2C are partial cross-sectional views of FIG.

3A and 3B are a plan view and a cross-sectional view of a filter bag.

4 (a) and 4 (b) are a plan view and a cross-sectional view of a mount for supporting a filter bag.

FIG. 5 is a cross-sectional view illustrating a filtration separation tank.

FIG. 6 is a cross-sectional view showing a septic tank of a septic tank.

[Explanation of symbols]

 1 side filtration surface 2 bottom filtration surface 3 sheath cylinder 4 filter residue storage chamber 11 pipe leg 12 upper girder terminal fixing part 13 bag support column 100 filtration separation tank body 101 tank side wall 102 bag outer cylinder wall 103 cylinder wall lower water inlet 104 Filtration clean water discharge pipe 105 Filtration bag fixing girder 200 Raw water receiving tank 201 Receiving tank body 202 Raw water injection pipe 300 Filtered raw water supply pipe 400 Filter residue discharge pipe

Claims (2)

[Claims] 1. A filtering bag formed of a monofilament yarn woven plain weave or twill weave single filter net made of highly non-adhesive synthetic resin. 2. An open type low gravity pressure filtration device comprising the filtration bag of claim 1 and comprising a filtration tank provided with an injection passage for a fluid to be filtered and a filtration cake discharge passage.