WO2023152939A1

WO2023152939A1 - Filtering material, filtering device, and filtering material production method

Info

Publication number: WO2023152939A1
Application number: PCT/JP2022/005539
Authority: WO
Inventors: 哲郎上山
Original assignee: 協和機電工業株式会社
Priority date: 2022-02-14
Filing date: 2022-02-14
Publication date: 2023-08-17
Also published as: JPWO2023152939A1; JP7122053B1

Abstract

[Problem] The purpose of the present invention is to provide: a filtering material capable of maintaining filtration processing performance over a long period and at a low cost; a filtering device; and a filtering material production method. [Solution] A filtering material 3 enclosed in a filtering device 1 is a composite fibrous body 31 in which a first fibrous body 311 that has polyethylene terephthalate as a material thereof and a second fibrous body 312 that has a polyamide as a material thereof are twisted at a prescribed ratio. A fiber element 32 is obtained by winding up one composite fibrous body 31 a prescribed number of turns, and the filtering material 3 is produced by bundling a plurality of fiber elements 32.

Description

FILTERING MATERIAL, FILTRATION APPARATUS, AND METHOD FOR MANUFACTURING FILTER MATERIAL

The present invention relates to a filtering medium, a filtering device, and a method for manufacturing a filtering medium. More specifically, the present invention relates to a filter medium, a filter device, and a method for manufacturing a filter medium that can maintain filtration performance for a long period of time.

Sewage (water to be treated) discharged from general households and factories contains various suspended solids. Due to the negative impact on the environment, various laws and regulations that set environmental standards set standards for the water quality that can be discharged.

A sand filtration method using a sand filtration device, for example, is known as one of the purification treatment methods for converting such water to be treated into treated water with less environmental impact. As a general sand filtration device used in the sand filtration method, Patent Document 1 discloses a sealed tank and a sand layer filled in the tank, and the water to be treated introduced from above the tank is placed in the sand layer. A filtering device is disclosed that is configured to filter at a low temperature and discharge the filtered water from the bottom of the tank.

On the other hand, sand filtration devices tend to have a high filtration resistance due to the high packing density of the filtering material. Therefore, the overall treatment capacity is inferior, so when installed in a large-scale industrial facility such as a factory for the purpose of treating industrial wastewater, the sewage treatment effect is not necessarily sufficient, and all suspended solids cannot be removed. is difficult.

For this reason, filtration equipment that uses fibrous material as a filter material with higher processing capacity is mainly used in industrial facilities. As a specific structure of the filtering device, for example, as disclosed in Patent Document 2, a filtering device having a filtering medium composed of a plurality of bundles of long fibers is generally known.

The filtration device disclosed in Patent Document 2 removes suspended solids contained in the water to be treated by causing the water to be treated to flow through the filtering material during filtration operation. At this time, by increasing the packing density of the filtering medium by consolidating the filtering medium, the water flow rate of the water to be treated is optimized, thereby removing the suspended solids more efficiently. Then, the water to be treated that has passed through the filtering material is purified into treated water from which most of the suspended solids have been removed.

In addition, in order to maintain the filtering capacity of the filtering material, a cleaning operation (backwashing operation) is performed to wash suspended solids adhering to the filtering material at regular intervals. In this backwashing operation, the filter media are washed by supplying air or backwash water (hereinafter collectively referred to as "cleaning fluid") while the filter media are extended. By alternately performing the filtering operation and the backwashing operation for each constant cycle, the filtering ability of the filtering material can be recovered.

The compaction and elongation of the filter media are generally performed using the water pressure of the water to be treated or the cleaning fluid, but some filter media are performed using an external driving force such as electrical energy. In some cases. In the case of using an external driving force, the filter media is forcibly compacted by the external driving force during the filtering operation to enhance the filtration processing performance, and the external driving force is also used during the backwashing operation to forcibly and quickly filter. The material is stretched to improve cleaning efficiency.

However, using an external driving force each time a filtering operation and a backwashing operation, as in the conventional technology, raises the energy cost and poses problems such as maintenance of the driving source of the external driving force. On the other hand, when a relatively small external driving force is used for energy-saving operation, the filter media cannot be sufficiently compacted during filtration operation, so that high filtration performance cannot be maintained, and the filter media cannot be sufficiently stretched during backwashing operation. Therefore, there is a problem that efficient cleaning treatment cannot be performed.

Therefore, in Patent Document 3, the applicant of the present application discloses a filtering device that performs filtering operation and backwashing operation with high efficiency based on a relatively simple configuration without using an external driving force. Specifically, a filtering device is disclosed in which the lower end of a filtering material is fixed, and the in-cylinder movable part having a concave portion formed downward is fixed to the upper end.

In the filtering device according to Patent Document 3, the movable part inside the cylinder is pressed downward by the water pressure of the water to be treated flowing from upstream to downstream during filtering operation. At this time, the filtering material is sufficiently compacted by the weight of the in-cylinder movable portion, so that the filtering process can be performed with high efficiency. On the other hand, during the backwash operation, the air and backwash water jetted from downstream to upstream accumulate in the concave portion formed in the in-cylinder movable portion, and an upward buoyancy is generated in the in-cylinder movable portion. This buoyancy pulls the filter material upward, and as a result, the filter material is sufficiently stretched and washed with high efficiency.

JP-A-5-154309 JP-A-2000-5517 Japanese Patent No. 6325746

According to the filtering device according to Patent Document 3 described above, since the filtering material can be compacted and stretched without using an external driving force, it can be operated at a low cost. On the other hand, if the filtration operation is continued, if the packing density of the filter media increases or if the water to be treated is supplied at an excessive speed, the gaps between the fibers that make up the filter media become smaller and the pressure loss increases. However, there is a problem that the duration of the filtering operation is shortened. Further, if the pressure loss of the filtering material increases, there is a concern that the pressure resistance of the entire filtering device may become a cause of failure.

Furthermore, if the duration of filtration operation is shortened, the period of filtration operation and backwash operation will be shortened, but if the operation cycle of filtration operation and backwash operation is repeated for a long period of time, ratio becomes high, resulting in inefficiency, and causes wear and deterioration of the fibers that make up the filtering material, requiring frequent replacement.

The present invention has been devised in view of the above points, and an object of the present invention is to provide a filtering material, a filtering device, and a method for manufacturing the filtering material that can maintain filtering performance for a long period of time. .

In order to achieve the above object, the filter medium of the present invention comprises at least one first fiber selected from the group consisting of polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate. A composite fibrous body constructed by mutually twisting a body and at least one second fibrous body selected from the group consisting of polyamide, polypropylene, polyethylene, and polyvinyl chloride.

Here, the composite fibrous body constituting the filter medium contains at least one first fibrous body selected from the group consisting of polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate. Accordingly, the removal rate of fine particles contained in the water to be treated can be increased. In addition, since the material selected for the first fibrous body has excellent tensile strength, even if the filter material is stretched during backwashing, a certain strength is secured and the composite fibrous body is prevented from being cut. be able to.

Further, since the composite fibrous body contains at least one second fibrous body selected from the group consisting of polyamide, polypropylene, polyethylene, and polyvinyl chloride, the material selected for these second fibrous bodies is generally Since it is excellent in flexing resistance, the decrease in strength due to repeated expansion and contraction of the filtering material is less than that of the first fibrous body. Therefore, by including a certain amount of the second fibrous body in the composite fibrous body, it is possible to suppress the deterioration of the filter medium due to repeated use and maintain the filtering performance for a long period of time.

Further, in the composite fibrous body, when the mixing ratio of the first fibrous body and the second fibrous body is in the range of 1:0.5 to 1:1, the fine particle removal performance of the first fibrous body and the It is possible to increase the strength of the filtering medium by the second fibrous body.

If the mixing ratio of the second fibrous body to the first fibrous body is less than the numerical range described above, the strength of the filtering material will be lowered, the filtering material will deteriorate in a short period of time, and there is a possibility that the removal rate of fine particles will decrease. There is On the other hand, if the mixing ratio of the second fibrous body to the first fibrous body is larger than the numerical range described above, although the strength of the filter medium increases, the effect of removing fine particles by the first fibrous body cannot be obtained. There is a possibility that the removal rate of fine particles may decrease.

Further, when the number of twists of the conjugate fiber body is 20 to 60 T/m, the strength of the conjugate fiber body is appropriate due to the synergistic effect of the first fibrous body and the second fibrous body. The removal rate of is increased, and the performance of the filter medium can be maintained for a long period of time.

If the number of twists of the composite fiber body is less than 20 T/m, the first fiber body and the second fiber body are not in close contact with each other, and the strength of the composite fiber body is lowered, and the fine particles are removed by the filtering material. There is a possibility that the performance cannot be maintained for a long time. On the other hand, when the number of twists of the composite fiber body is more than 60 T/m, the first and second fibrous bodies are tightly entwined, so that when the composite fiber body is washed, for example, it adheres to the inside of the composite fiber body. A problem arises in that the fine particles that have formed are difficult to be discharged to the outside. Furthermore, since the gap between one composite fibrous body and the adjacent composite fibrous body increases and the porosity of the portion through which the treated water passes increases, there is a possibility that the fine particle removal rate may decrease.

To achieve the above object, the filtering device of the present invention comprises at least one first fiber selected from the group consisting of polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate. body and at least one second fibrous body selected from the group consisting of polyamide, polypropylene, polyethylene, and polyvinyl chloride are twisted together to solid-liquid separate the water to be treated supplied during the filtration operation. an outer cylindrical portion enclosing the filtering medium; a first filtering medium fixing section fixing the downstream end of the filtering medium; and an open end toward the first filtering medium fixing section. is formed, is positioned upstream of the filter material and is movable along the axial direction of the outer cylindrical portion, and is provided to consolidate the filter material by its own weight. and a second filter medium fixing part provided on the open end surface of the in-cylinder movable part for fixing the upstream end of the filter medium.

Here, by providing a filtering material configured by mutually twisting the first fibrous body and the second fibrous body and performing solid-liquid separation of the water to be treated supplied during the filtration operation, the In addition, deterioration of the filtering material due to repeated use can be prevented, and filtering performance can be maintained for a long period of time.

In addition, by providing the outer cylindrical portion that contains the filtering material, the water to be treated that contains suspended solids can be purified by the contained filtering material by supplying the water to be treated into the outer cylindrical portion.

Further, by providing the first filter medium fixing portion for fixing the downstream end of the filter medium, the end of the filter medium can be fixed. As a result, when the filter device is backwashed by supplying the cleaning fluid from the downstream side to the upstream side in the outer cylindrical portion, the filter medium extends toward the upstream side with the first filter medium fixing portion as a base point. Therefore, the cleaning effect can be enhanced.

In addition, the in-cylinder movable portion has a concave shape with an open end facing the first filter medium fixing portion and is movable along the axial direction of the outer cylindrical portion. can be moved along the axial direction of the outer cylindrical portion by the hydraulic pressure of the water to be treated. That is, without using an external driving force, the water pressure of the water to be treated can consolidate the filtering material to increase the packing density.

Since the in-cylinder movable part is positioned upstream of the filter material and is provided to consolidate the filter material by its own weight, during the filtration operation, the in-cylinder movable part is affected by the water pressure of the water to be treated supplied from the upstream side. At the same time, it is pressed toward the downstream side by its own weight. At this time, the filtering material is compacted to have an appropriate packing density, and the removal rate of suspended solids can be increased.

In addition, by providing the second filter medium fixing part that is provided on the open end face of the in-cylinder movable part and fixes the upstream end of the filter medium, the in-cylinder movable part and the filter medium can be integrated. . Therefore, the filtering medium can be sufficiently compacted only by the water pressure of the water to be treated and the weight of the movable part in the cylinder without using an external driving force.

In addition, the filtering material includes a first filtering material located upstream in the direction of supply of the water to be treated during the filtration operation, and a fiber of the first filtering material located downstream of the first filtering material. In the case of having a second filter medium having a fiber diameter relatively smaller than the diameter, the filter medium can have a two-layer structure of the upstream side and the downstream side. As a result, during the filtration operation, the first filtering material located upstream removes suspended solids with a relatively large volume, and the second filtering material located downstream removes suspended solids with a relatively small volume. Therefore, the effect of treating the water to be treated can be further enhanced.

In order to achieve the above object, the method for producing a filter medium of the present invention comprises at least one selected from the group consisting of polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate. a step of twisting one fibrous body and at least one second fibrous body selected from the group consisting of polyamide, polypropylene, polyethylene, and polyvinyl chloride with a predetermined number of twists; a step of winding the composite fiber body with a predetermined number of turns, a step of heating the fiber elements produced in the winding step at a predetermined heating temperature, a step of impregnating the fiber elements with a cleaning agent, and a plurality of fiber elements. and a step of binding.

Here, by providing the step of twisting the first fibrous body and the second fibrous body with a predetermined number of twists, it is possible to increase the removal rate of fine particles contained in the water to be treated, and to increase the removal rate of fine particles contained in the water to be treated. It is possible to prevent deterioration of the material and maintain filtration performance for a long period of time.

Further, by providing a step of winding the composite fibrous body produced in the twisting step with a predetermined number of turns, it is possible to produce a fiber element, which is one element constituting the filtering material.

In addition, by providing a step of heating the fiber element generated in the winding step at a predetermined heating temperature, the fiber crimp is controlled and the surface area of the fiber element is secured, thereby increasing the removal rate of fine particles by the filter medium. can be enhanced.

In addition, by providing the step of impregnating the fiber elements with the cleaning agent, dirt adhering to the surface of the composite fiber body can be removed in the process of producing the fiber elements, and the removal rate of fine particles by the filter medium can be increased.

In addition, by including the step of bundling a plurality of fiber elements, it is possible to produce a filter medium having a plurality of fiber elements as constituent elements.

The filtering material, the filtering device, and the method for manufacturing the filtering material according to the present invention can maintain filtering performance for a long period of time.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the outline of the filtering apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows a filter medium, (a) shows a composite fibrous body, (b) shows a fiber element, (c) shows a filter medium, respectively. It is a manufacturing-process figure of a filter medium. FIG. 4 is an external view of a first filtering medium fixing portion that constitutes the filtering device according to the first embodiment of the present invention; FIG. 3 is an external view of a cylinder movable portion that constitutes the filtering device according to the first embodiment of the present invention, where (a) is a side view and (b) is a bottom view. It is a figure which shows the state at the time of the filtration operation of the filtration apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the state at the time of backwashing operation|movement of the filtration apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the outline of the filtering apparatus which concerns on the 2nd Embodiment of this invention. It is a graph which shows the filtration test result in an Example and a comparative example.

Hereinafter, a filtering medium, a filtering device, and a filtering medium manufacturing method according to embodiments of the present invention will be described with reference to the drawings for understanding of the present invention. In the following description, when the filter material is installed in the outer cylinder, the upward direction is upward, the opposite direction is downward, the axial direction represented by upward and downward is the vertical direction, and the vertical direction is perpendicular to the vertical direction. defined as the horizontal direction, respectively.

[First embodiment]
First, a filtering device 1 according to a first embodiment of the present invention will be described with reference to FIG. The filtering device 1 mainly comprises an outer tube portion 2 , a filter medium 3 , a filter medium fixing portion 4 , an in-cylinder movable portion 5 , and a stopper portion 6 .

[Outer cylinder]
The outer cylinder part 2 is made of stainless steel and is composed of an outer cylinder main body part 21 , an outer cylinder upper end part 22 and an outer cylinder lower end part 23 . More specifically, the outer cylinder portion 2 according to the present embodiment includes a cylindrical outer cylinder body portion 21, an outer cylinder upper end portion 22 attached to a position above the outer cylinder body portion 21, and the outer cylinder body It consists of a lower end portion 23 of the outer cylinder attached to the lower portion of the portion 21 .

The outer cylinder main body portion 21 can be divided vertically, and a stopper portion 6, which will be described later, is inserted in the dividing surface. When the filtering material 3 is deteriorated or the like, replacement work of accessories in the outer cylinder part 2 or maintenance work inside the outer cylinder part 2 can be performed by dividing the outer cylinder main body part 21 in the vertical direction. It is something that can enhance sexuality.

Here, the material of the outer cylinder body portion 21, the outer cylinder upper end portion 22, and the outer cylinder lower end portion 23, which constitute the outer cylinder portion 2, does not necessarily have to be stainless steel. For example, iron, polyvinyl chloride, FRP, polyethylene, acrylic resin, polypropylene, or the like may be used.

Also, the outer tube portion 2 does not necessarily have to be cylindrical. It may be of any shape as long as it has a predetermined space in which a device for passing and filtering the water to be treated can be placed.

Also, the outer cylinder part 2 does not necessarily have to be of a split type. However, since it is a split type, the efficiency of the maintenance work of the filter device 1 can be improved as described above.

The outer cylinder upper end 22 of the outer cylinder part 2 has an upper inlet/outlet part 221 for passing the water to be treated, and an air vent part for periodically discharging the air filled in the outer cylinder part 2 to the outside. 222 is provided. A first branch pipe 223 is connected to the upper inlet/outlet portion 221 . Also, the air vent portion 222 is configured to be openable and closable as required.

One side of the first branch pipe 223 connected to the upper entrance/exit portion 221 is connected via a first upper valve 224 to a water supply portion A to which water to be treated is supplied. Also, the other side of the first branch pipe 223 is connected via a second upper valve 225 to a drainage discharge section B for discharging the backwash water.

A lower inlet/outlet portion 231 and an air introduction portion 232 for introducing air introduced from a blower C, which will be described later, into the outer cylinder portion 2 are provided at the outer cylinder lower end portion 23 of the outer cylinder portion 2 . A second branch pipe 233 is connected to the lower inlet/outlet portion 231 .

A treated water reservoir D is connected via a first lower valve 234 to one side of the second branch pipe 233 connected to the lower inlet/outlet portion 231 . A backwash water supply section E is connected to the other side of the second branch pipe 233 via a second lower valve 235 .

The lower end portion 23 of the outer cylinder is provided with the air introduction portion 232 as described above, and the air introduction portion 232 is connected to the aeration pipe portion 236 provided inside the lower end portion 23 of the outer cylinder. A blower C is connected to the air introduction portion 232 via an air pipe (not shown). That is, in this embodiment, air is configured to be supplied from the blower C to the aeration pipe portion 236 via the air introduction portion 232 . A plurality of through-holes are formed in the aeration pipe portion 236 to eject air.

[Filtration material]
The filtering medium 3 is composed of a composite fibrous body 31 of a first fibrous body 311 made of polyethylene terephthalate (PET) and a second fibrous body 312 made of polyamide (PA). FIG. 2(a) is an enlarged view of the composite fiber body 31. FIG. As shown in FIG. 2(a), a first fibrous body 311 and a second fibrous body 312 are twisted to form a single composite fibrous body 31. Further, as shown in FIG. 2(b), the composite fibrous body 31 is wound a predetermined number of times to form the fiber element 32 that constitutes the filter medium 3 .

Here, it is not always necessary to select polyethylene terephthalate as the material of the first fibrous body 311, and at least one selected from the group consisting of polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate. shall be selected.

Also, it is not always necessary to select polyamide as the material for the second fibrous body 312, and at least one selected from the group consisting of polyamide, polypropylene, polyethylene, and polyvinyl chloride.

In the composite fibrous body 31 of this embodiment, the first fibrous body 311 and the second fibrous body 312 are twisted at a mixing ratio (mass ratio) of approximately 1:0.5 to 1:1.

Here, the mixing ratio of the first fibrous body 311 and the second fibrous body 312 is not necessarily limited to the range of approximately 1:0.5 to 1:1. For example, the second fibrous body 312 is superior to the first fibrous body 311 in bending resistance, and the decrease in strength due to repeated use of the filter medium 3 is smaller than that of the first fibrous body 311. It is also possible to further increase the mixing ratio of the bodies 312 .

However, the tensile strength of the second fibrous body 312 tends to be weaker than the tensile strength of the first fibrous body 311 . Therefore, if the ratio of the second fibrous bodies 312 to the first fibrous bodies 311 is increased, the second fibrous bodies 312 cannot withstand the tensile force and are split when the filtering medium 3 is washed by backwashing. There is fear. Therefore, from the viewpoint of maintaining the filtering performance of the filter medium 3 for a long period of time while maintaining a certain tensile strength, the mixing ratio of the first fibrous bodies 311 and the second fibrous bodies 312 is approximately 1:0. A ratio of 5 to 1:1 is preferred.

In the composite fibrous body 31 of this embodiment, the number of twists between the first fibrous body 311 and the second fibrous body 312 is 20 to 60 T/m, more preferably 50 T/m. By setting the number of twists of the first fibrous body 311 and the second fibrous body 312 within the range of 20 to 60 T/m, the first fibrous body 311 and the second fibrous body 312 are properly twisted. , the durability and filtration performance of the filtering medium 3 can be improved.

Here, if the number of twists is less than 20 T/m, the strength of the composite fibrous body 31 is weakened, so there is a possibility that the performance of removing fine particles will vary when the filtering medium 3 is used for a long time. On the other hand, if the number of twists is more than 60 T/m, the first fibrous body 311 and the second fibrous body 312 are too closely attached to each other. It is difficult for the dirt adhering to the filter to be discharged to the outside, and as a result, there is a possibility that the filtration performance of the filter medium 3 will vary. Therefore, from the viewpoint of maintaining the filtration performance for a long time while ensuring the strength of the filter medium 3, the number of twists between the first fibrous body 311 and the second fibrous body 312 should be 20 to 60 T/m. is preferred.

[Method for manufacturing filter material]
Next, the manufacturing process of the filter medium 3 will be described with reference to the process diagram of FIG.

<STEP 1: Production of composite fiber body>
First, the filamentous first fibrous body 311 and the second fibrous body 312 are each twisted together under the conditions of the twist number (20 to 60 T/m), and the composite fibrous body 31 shown in FIG. 2(a) is obtained. generated. The mixing ratio of the first fibrous body 311 and the second fibrous body 312 is adjusted in the range of 1:0.5 to 1:1 as described above. In the embodiment of the present invention, the number of twists was 50 T/m, and the mixing ratio of the first fibrous body 311 and the second fibrous body 312 was 1:1.

<STEP2: Generation of Fiber Elements>
The composite fiber body 31 produced in STEP 1 is wound by a winding device (not shown) to produce an endless fiber element 32 as shown in FIG. 2(b).

<STEP 3: Heating the fiber element>
By heating the fiber elements 32 produced in STEP 2, the fibers are crimped to some extent, and the inter-fiber distance between the first fibrous body 311 and the second fibrous body 312 can be appropriately maintained. Furthermore, by forcibly crimping the fibers by heating, excessive crimping of the fibers in subsequent steps can be suppressed. Note that the heating temperature and the heating time can be appropriately changed according to the type of fiber material forming the composite fiber body 31, and the like.

<STEP 4: Washing the fiber element>
The composite fibrous body 31 constituting the fibrous element 32 contains the lubricating oil used when twisting the first fibrous body 311 and the second fibrous body 312, and especially the nylon which is the material of the second fibrous body 312. Impurities such as monomers that are dissolved may adhere to the surface. If the filter medium 3 is used in a state in which these impurities are adhered, the removal performance of the filter medium 3 may be adversely affected. Impurities adhering to the surface of the composite fiber body 31 can be removed by immersing the fiber element 32 in the cleaning liquid for a certain period of time. In addition, you may make it further wash with tap water etc. after immersion.

<STEP 5: Bundling Fiber Elements>
By bundling the plurality of fiber elements 32 washed in STEP 4 and tying the ends, one filter medium 3 is completed as shown in FIG. 2(c). The number of fiber elements 32 to be bundled can be appropriately changed according to the size of the filtering device using the filtering medium 3 .

[Filtration medium fixing part]
The filtering medium fixing part 4 is for fixing the filtering medium 3 inside the outer cylinder part 2 , and in a state in which the filtering medium 3 is installed inside the outer tubular part 2 , the filtering medium fixing part 4 is for fixing the lower end of the filtering medium 3 . 1 filter medium fixing part 41 and a second filter medium fixing part 42 for fixing the upper end of the filter medium 3 . The first filtering medium fixing part 41 is installed above the lower end part 23 of the outer cylinder, and the second filtering medium fixing part 42 is installed inside the inside movable part 5 described later.

Here, the first filter medium fixing portion 41 does not necessarily have to be installed at the position shown in FIG. shall be possible.

Since the first filter medium fixing portion 41 and the second filter medium fixing portion 42 have substantially the same shape, the first filter medium fixing portion 41 will be described here as a representative example. As shown in FIG. 4, the first filter medium fixing portion 41 forms a lattice portion 43 in which linear stainless steel members are arranged at regular intervals in the vertical and horizontal directions. The lower end portion of the filter medium 3 is fixed to one of the first filter medium fixing portions 41 (straight line portion or intersection portion) via a string-like attachment member (not shown). Further, the upper end portion of the filter medium 3 is fixed to any part of the second filter medium fixing portion 42 via a string-like attachment member (not shown).

Here, it is not necessary for the first filter medium fixing part 41 and the second filter medium fixing part 42 to constitute the lattice part 43 . Any shape can be used as long as the filter medium 3 can be firmly fixed even when the water to be treated is passed through the filter medium 3 during the filtration operation, or when a cleaning fluid such as air is supplied during the backwashing operation. Such a configuration may be used.

[Movable part in cylinder]
The in-cylinder movable portion 5 moves up and down in the outer cylinder portion 2 under the water pressure of the water to be treated supplied from the upstream side of the outer cylinder portion 2 and the water pressure of the cleaning fluid supplied from the downstream side of the outer cylinder portion 2 . It is configured to be movable in any direction. 5A and 5B are schematic diagrams of the in-cylinder movable portion 5. FIG. 5A is a schematic side view of the in-cylinder movable portion 5, and FIG. 5B is a schematic bottom view of the in-cylinder movable portion 5. Figure shows.

As shown in FIG. 5, the in-cylinder movable portion 5 according to the present embodiment includes a concave movable main body portion 51 and a second filter medium fixing portion 42 provided inside the movable main body portion 51. , a spacer ring 53 provided outside the movable main body 51, and a check valve 55 for controlling the opening/closing state of a fluid communication hole 54 provided above the movable main body 51, and the like. .

A movable concave portion 52 that is a predetermined space is formed inside the movable body portion 51 . In addition, a fluid communication hole 54 is formed substantially in the upper center of the movable main body 51, and four adjustment holes 56 are formed around the fluid communication hole 54 at regular intervals. there is

Here, the movable body portion 51 does not necessarily have to be bowl-shaped. As long as the movable concave portion 52, which is a predetermined space, is formed inside the movable body portion 51, the outer shape is not particularly limited. That is, if the water to be treated supplied exerts a pressing force in the downstream direction during the filtering operation of the filtration device 1, and a buoyant force in the upstream direction can be generated during the backwashing operation, what shape is the outer shape of the filtering device 1? There may be.

A check valve 55 is provided above the fluid circulation hole 54 formed in the movable main body 51 , and the opening/closing state of the fluid circulation hole 54 is controlled by this check valve 55 . That is, when the water to be treated is supplied from above the in-cylinder movable part 5, the fluid flow hole part 54 formed in the movable main body part 51 is in an "open" state, and the water to be treated flows downward. It functions to circulate. In addition, when backwash water, air, or the like is supplied from below the in-cylinder movable portion 5, the fluid circulation hole portion 54 is closed so that the movable body portion 51 floats upstream. It functions as a device for generating buoyancy.

The adjustment hole portion 56 formed in the movable main body portion 51 functions to circulate the water to be treated and the cleaning fluid in the vertical direction of the in-cylinder movable portion 5 . In the present embodiment, adjustment holes 56 are formed at four locations, and the posture of the in-cylinder movable portion 5 that moves up and down inside the outer cylinder portion 2 is determined by the flow of fluid through these adjustment holes 56 . Balance is maintained.

Here, the adjustment hole portion 56 may not necessarily be formed in the movable main body portion 51 . However, by forming the adjustment hole portion 56, the posture balance of the in-cylinder movable portion 5 that moves up and down inside the outer cylinder portion 2 can be kept constant. Therefore, the filtration efficiency can be enhanced by making the packing density of the filtering media 3 uniform during the filtering operation, and the cleaning effect can be enhanced by uniformly stretching the entire filtering media 3 during the extension.

Also, the adjustment holes 56 do not necessarily have to be formed at four locations. The number of adjustment holes 56 can be appropriately changed according to the shape, size, etc. of the in-cylinder movable portion 5 . Further, the opening/closing state of these adjustment holes 56 may be appropriately adjusted while observing the vertical movement state of the in-cylinder movable portion 5 . For example, if desired, one or more of the adjustment holes 56 may be closed using bolts, pins, or the like.

A spacer ring 53 is provided on the outer side of the movable body portion 51, as shown in FIG. The outer diameter of the spacer ring 53 is slightly smaller than the inner diameter of the outer cylindrical portion 2 (in the embodiment of the present invention, the distance from the inner wall surface is about 0.5 mm to 5.0 mm), and the movable It can be integrated with the body portion 51 or attached detachably. The spacer ring 53 is made of a material having a small coefficient of friction and excellent wear resistance, such as fluororesin, high-molecular-weight polyethylene resin, hard polyethylene resin, or the like.

Here, it is not always necessary to provide the spacer ring 53. However, by providing the spacer ring 53, the sliding effect of the in-cylinder movable portion 5 on the inner wall surface of the outer cylinder portion 2 can be enhanced, and the vertical movement can be performed more smoothly. Further, by providing the spacer ring 53 , the gap between the inner wall surface of the outer cylindrical portion 2 and the in-cylinder movable portion 5 is reduced, and the pressure of the water to be treated is effectively applied to the in-cylinder movable portion 5 .

Inside the movable body portion 51 that constitutes the in-cylinder movable portion 5, the second filter medium fixing portion 4 is provided as shown in FIG. 5(b). Since the shape of the second filter medium fixing portion 4 is substantially the same as that of the first filter medium fixing portion 4 as described above, description thereof will be omitted here.

As described above, the upper and lower ends of the filter medium 3 are firmly fixed by the first filter medium fixing part 41 and the second filter medium fixing part 42 . During the filtering operation of the filtering device 1, the in-cylinder movable part 5 receives the water pressure of the water to be treated supplied from above and moves downward. Conversely, during the backwashing operation of the filter device 1, the in-cylinder movable portion 5 receives the hydraulic pressure of the backwashing fluid supplied from below and moves upward. In this manner, the compression and extension of the filter material 3 can be repeated as the movable main body 51 moves up and down.

Next, a method for operating the filtering device 1 according to the embodiment of the present invention will be described. The filtering device 1 mainly alternately and repeatedly performs "filtration operation" and "backwashing operation". The "backwashing operation" is a concept including, for example, both "air backwashing operation" that supplies only air and "mixed backwashing operation" that simultaneously supplies air and backwashing water.

[Filtration operation]
FIG. 6 is a diagram showing the state of the filtering device 1 during filtering operation. When starting filtration operation, the first upper valve 224 is in the "open" state, the second upper valve 225 is in the "closed" state, the first lower valve 234 is in the "open" state, and the second lower valve 235 is in the "closed" state. ” state, each valve is opened and closed.

Next, the water to be treated is supplied from the water to be treated supply portion A into the outer cylinder portion 2 via the first upper valve 224 , the first branch pipe 223 , and the upper inlet/outlet portion 221 . Water to be treated is supplied into the outer cylindrical portion 2, and when the in-cylinder movable portion 5 moves downward under the pressure of the water, the filtering medium 3 moves along with the water pressure of the supplied water to be treated. The weight of the in-cylinder movable portion 5 fixed to the upper end pushes it further downward. At this time, the movement of the in-cylinder movable portion 5 is restricted at a fixed height position by the stopper portion 6, and the position is fixed. Therefore, the packing density of the compacted filtering medium 3 is kept uniform during the filtering operation.

When the water to be treated continues to be supplied while the filter medium 3 is compacted, the water to be treated supplied from the upper inlet/outlet portion 221 mainly flows through the fluid circulation hole portion 54 of the in-cylinder movable portion 5 and the adjustment valve. It flows through the holes 56 , the gap between the spacer ring 53 and the outer cylinder main body 21 , and then repeatedly contacts with the filtering material 3 . That is, the water to be treated is repeatedly brought into contact with the filtering material 3 that has been compacted to a certain packing density, whereby suspended solids contained in the water to be treated are efficiently removed.

After the water to be treated repeatedly contacts with the filtering material 3 and passes through it, it becomes treated water from which suspended solids have been removed. This treated water is sent to the treated water reservoir D via the lower inlet/outlet portion 231 , the second branch pipe 233 and the first lower valve 234 . The treated water sent to the treated water reservoir D is used for the backwashing process and other purposes described later.

[Backwash operation]
The filtering device 1 shifts from the filtering operation to the backwashing operation at a predetermined timing in order to wash the filtering material 3 and recover the filtering performance. The timing for performing the backwash operation is when the differential pressure across the filter media 3 rises to a predetermined value or more, or when the turbidity of the water to be treated and the treated water is measured and the suspended solids contained in the water to be treated are determined. When the removal rate of is calculated and falls below a predetermined removal rate, or when a certain period of time has passed since the start of the filtration operation.

FIG. 7 is a schematic diagram showing the state of the filtration device 1 during the backwashing process. When performing the backwashing operation using the filtration device 1 according to the present embodiment, each valve is opened and closed at the time of transition from the filtration operation to the washing operation, and then air is supplied, backwashing water, etc. are performed. of backwash fluid is supplied.

First, when shifting from the filtration operation to the backwash operation, the first upper valve 224 is in the "closed" state, the second upper valve 225 is in the "open" state, the first lower valve 234 is in the "closed" state, and the second upper valve 224 is in the "closed" state. Each valve is opened and closed so that the lower valve 235 is in the "closed" state.

Next, after the valves are opened and closed as described above, air is supplied from the blower C to the aeration pipe section 236 through the air introduction section 232 (air backwashing operation). Since a large number of air ejection holes (not numbered) are formed in the aeration pipe portion 236, when air is supplied from the blower C through the air introduction portion 232, the air ejection holes of the aeration pipe portion 236 Air is jetted upward in the outer cylindrical portion 2 from the .

When air is ejected into the outer cylinder portion 2 from the air ejection holes of the aeration pipe portion 236, an air flow is formed upwardly of the outer cylinder portion 2, and the rising air flows into the movable concave portion of the in-cylinder movable portion 5. It accumulates within 52. At this time, some air leaks from the adjustment hole 56 formed in the in-cylinder movable portion 5 and the gap between the spacer ring 53 and the outer cylinder main body 21 . Since the check valve 55 is closed by the flow of air, air does not leak from the fluid communication hole 54 and a predetermined amount of air stays in the movable recess 52 .

In this way, the in-cylinder movable portion 5 has buoyancy due to the accumulation of a predetermined amount of air in the movable concave portion 52 of the in-cylinder movable portion 5 . Furthermore, a small amount of air escapes upward from the adjustment hole 56 formed in the in-cylinder movable portion 5, and the upward movement of the in-cylinder movable portion 5 is stabilized by the upward flow of air. That is, when the in-cylinder movable portion 5 moves upward due to the buoyancy, the flow of air from the adjustment hole portion 56 can reduce lateral deflection of the in-cylinder movable portion 5 .

Since the in-cylinder movable part 5 moves upward from the outer cylinder part 2 due to the buoyancy, the filter material 3 whose upper end is fixed to the in-cylinder movable part 5 moves along with the movement of the in-cylinder movable part 5. From the compacted state shown in FIG. 6, the expanded state shown in FIG. 7 is reached. In this manner, the air supplied from below the outer cylindrical portion 2 moderately loosens the filter media 3 that have been compressed during the filtration operation, and the cleaning effect of the filter media 3 can be enhanced. The wastewater generated by this air backwashing operation is discharged to the wastewater discharge portion B via the upper inlet/outlet portion 221 , the first branch pipe 223 and the second upper valve 225 .

Following the air backwash operation, a mixed backwash operation that supplies both air and backwash water is performed. In this mixed backwash operation, the first upper valve 224 is in the "closed" state, the second upper valve 225 is in the "open" state, the first lower valve 234 is in the "closed" state, and the second lower valve 235 is in the "open" state. Each valve is opened and closed so as to achieve the state. That is, the first upper valve 224, the second upper valve 225, and the first lower valve 234 maintain the same state as in the air backwash operation described above, and the second lower valve 235 is changed from the "closed" state to the "open" state. and

Air is supplied from the blower C to the aeration pipe section 236 via the air introduction section 232 after opening and closing each valve. Further, backwash water is supplied from the backwash water supply portion E to the outer cylinder lower end portion 23 via the second lower valve 235 , the second branch pipe 233 , and the lower inlet/outlet portion 231 .

As described above, when air is ejected from the air ejection holes of the aeration pipe portion 236 into the outer cylinder portion 2, an air flow is formed upwardly of the outer cylinder portion 2, and the rising air flows into the cylinder movable portion. It accumulates in the movable concave portion 52 of 5. Further, when the backwash water is supplied from the lower end portion 23 of the outer cylinder, the backwash water collides with the movable concave portion 52 of the in-cylinder movable portion 5, and the energy for moving the in-cylinder movable portion 5 upward together with the air is generated. acts as

At this time, a small amount of air and backwash water leaks from the adjustment hole 56 formed in the in-cylinder movable portion 5. Since the check valve 55 is closed, air and backwash water do not leak from the fluid flow hole 54 and a predetermined amount of air remains in the movable recess 52 .

As described above, the in-cylinder movable portion 5 has buoyancy due to the accumulation of a predetermined amount of air in the movable concave portion 52 of the in-cylinder movable portion 50 . In addition, the backwash water collides with the movable concave portion 52 of the in-cylinder movable portion 5 and acts as energy for moving the in-cylinder movable portion 5 upward together with the air.

As the in-cylinder movable part 5 moves upward, the filter medium 3, whose upper end is fixed to the in-cylinder movable part 5, is moved by the movement of the in-cylinder movable part 5, as shown in FIG. The state is further extended from the state of the backwash operation. Specifically, by performing this mixed backwashing operation, the in-cylinder movable portion 5 is moved upward to a predetermined height position of the outer cylinder portion 2, and the filter media 3 is also in a substantially completely extended state.

As described above, by performing the mixed backwashing operation, the in-cylinder movable portion 5 can be moved upward to further extend the filter medium 3 . In addition, since the backwash fluid is supplied upward while the filter media 3 is extended, the filter media 3 can be washed effectively. The backwashing fluid discharged by this mixed backwashing operation is discharged to the waste water discharging portion B via the upper inlet/outlet portion 221 and the second upper valve 225 .

The above is a series of filtration operations performed in the filtration device 1 according to the embodiment of the present invention. After the air backwash operation and the mixed backwash operation, the remaining backwash wastewater is sent downstream. For the purpose of preventing this, a flushing operation in which the water to be treated is supplied only for a certain period of time, or a water disposal process in which water remaining in the outer cylinder portion is disposed of may be performed. Also, the air backwashing operation does not necessarily have to be performed, and only the mixed backwashing operation may be performed.

[Second embodiment]
Next, a filtering device 1 according to a second embodiment of the present invention will be described. A filter device 1 according to the second embodiment is basically the same as that of the first embodiment, except for the configuration of the filter medium 3a, which is one of the constituent elements. Therefore, the configuration of the filtering material 3a different from that of the first embodiment will be mainly described below.

As shown in FIG. 8, the filter medium 3a according to the second embodiment has a configuration in which a first filter medium 300a and a second filter medium 300b having different fiber diameters are arranged vertically in two stages. As for the fiber diameters constituting the

respective filter media

300a and 300b, those having a smaller fiber diameter in the lower stage than in the upper stage are adopted (for example, the fiber diameter of the first filter medium 300a in the upper stage is approximately 33 μm, and the fiber diameter of the second filter medium in the lower stage is about 33 μm. The fiber diameter of the filtering material 300b is approximately 18 μm). The joining portion of the first filter medium 300a in the upper stage and the second filter medium 300b in the lower stage is integrated by binding with a string-like attachment member (not shown).

By making the fiber diameter of the lower second filter medium 300b smaller than that of the upper first filter medium 300a, when the filter medium 3a is compacted by the in-cylinder movable part 5, the upper filter medium The gap between the fibers of the lower second filter medium 300b is smaller than that of the first filter medium 300a. As a result, of the suspended solids contained in the water to be treated, the suspended solids having a relatively large volume are removed by the upper first filter medium 300a, and the suspended solids that cannot be removed by the upper first filter medium 300a are removed. Suspended solids with a relatively small volume can be removed by the lower second filter medium 300b. Therefore, suspended solids contained in the water to be treated can be filtered more efficiently.

With the above configuration, the filter medium 3a of the second embodiment can remove suspended solids in the water to be treated more reliably than the filter medium 3 of the first embodiment.

〔Example〕
Next, examples of the present invention will be described.

The specifications of the first fibrous body and the second fibrous body used in the filter medium of this example are as follows.
<First fibrous body>
Material: Polyethylene terephthalate Tensile strength: 3.6cN/dTex
Tensile elongation: 35%
<Second fibrous body>
Material: Polyamide Tensile strength: 3.0cN/dTex
Tensile elongation: 51%

The above first fibrous body and second fibrous body were twisted at a ratio of 1:1 under the condition of a twist number of 50 T/m to form a composite fibrous body. Then, the composite fiber body was wound a predetermined number of times by a winding device to produce a fiber element. Fifteen fiber elements thus produced were bundled to form a filter medium.

[Comparative example]
The comparative example is composed only of the first fibrous body, and the first fibrous body has the same specifications as described above. The first fibrous body was wound a predetermined number of times by a winding device to produce a fibrous element. Fifteen fiber elements thus produced were bundled to form a filter medium.

FIG. 9 is a graph showing the results of filtration tests (removal rate of fine particles versus time of passing water) for Examples and Comparative Examples. The test conditions are the results of a filtration test of 5 μm polymethyl methacrylate (PMMA) particles in both Examples and Comparative Examples.

As shown in FIG. 9, until the water flow time is 80 minutes, both the filter media of the examples and the comparative examples exhibit the same fine particle removal rate. On the other hand, when the water passing time exceeds 80 minutes, the removal rate of the filter material of the comparative example decreases. This is presumably because the fibrous body constituting the filtering material repeatedly expands and contracts with the passage of time, resulting in a decrease in elastic modulus, which deteriorates the effect of trapping fine particles. On the other hand, since the second fibrous body is included in the example, the decrease in elastic modulus due to the expansion and contraction of the fibrous body is suppressed. It can be read that the removal performance gradually deteriorates when the time exceeds 130 minutes.

In this way, it was confirmed that the maximum removal rate (100%) of the example and the comparative example exhibited the same performance, and that the example could maintain the maximum removal rate for a long time compared to the comparative example.

As described above, the filtering material, the filtering device, and the method for manufacturing the filtering material according to the present invention are low-cost and can maintain filtration performance for a long period of time.

Reference Signs List 1 filtration device 2 outer cylinder portion 21 outer cylinder body portion 22 outer cylinder upper end portion 221 upper inlet/outlet portion 222 air vent portion 223 first branch pipe 224 first upper valve 225 second upper valve 23 outer cylinder lower end portion 231 lower inlet/outlet portion 232 Air introduction part 233 Second branch pipe 234 First lower valve 235 Second lower valve 236

Aeration pipe part

3, 3a Filter material 31 Composite fiber body 311 First fiber body 312 Second fiber body 32 Fiber element 300a First Filter medium 300b Second filter medium 4 Filter medium fixing part 41 First filter medium fixing part 42 Second filter medium fixing part 43 Grating part 5 In-cylinder movable part 51 Movable main body part 52 Movable concave part 53 Spacer ring 54 Fluid distribution Hole part 55 Check valve 56 Adjustment hole part A Water supply part to be treated B Waste water discharge part C Air blower D Water to be treated storage part E Backwash water supply part

Claims

at least one first fibrous body selected from the group consisting of polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate;
A filter medium comprising a composite fibrous body formed by mutually twisting together a second fibrous body of at least one selected from the group consisting of polyamide, polypropylene, polyethylene, and polyvinyl chloride.
2. The filtering medium according to claim 1, wherein said composite fibrous body has a mixing ratio of said first fibrous body and said second fibrous body in a range of 1:0.5 to 1:1.
3. The filtering medium according to claim 1, wherein the number of twists of the composite fiber body is 20 to 60 T/m.
At least one first fibrous body selected from the group consisting of polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate, and selected from the group consisting of polyamide, polypropylene, polyethylene, and polyvinyl chloride a filtering material comprising a composite fibrous body configured by twisting together at least one second fibrous body and at least one second fibrous body, which separates the water to be treated supplied during the filtration operation into solid and liquid;
an outer cylindrical portion that encloses the filtering material;
a first filtering medium fixing part that fixes the downstream end of the filtering medium;
It has a concave shape with an open end facing the first filter medium fixing portion, is located upstream of the filter medium, is movable along the axial direction of the outer cylindrical portion, and has its own weight. an in-cylinder movable portion provided to consolidate the filtering material by
a second filter medium fixing part provided on the open end surface of the in-cylinder movable part and fixing the upstream end of the filter medium.
The filtering material is
a first filter medium located upstream in the direction of supply of the water to be treated during the filtering operation;
a second filter medium located downstream of the first filter medium and having a fiber diameter relatively smaller than that of the first filter medium;
5. The filtering device of claim 4.
At least one first fibrous body selected from the group consisting of polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate, and selected from the group consisting of polyamide, polypropylene, polyethylene, and polyvinyl chloride a step of twisting at least one second fibrous body with a predetermined number of twists;
a step of winding the composite fibrous body produced in the twisting step with a predetermined number of turns;
a step of heating the fiber element produced in the winding step at a predetermined heating temperature;
a step of impregnating the fiber element with a cleaning agent;
and a step of bundling a plurality of said fiber elements.
The twisting step includes
Under the condition that the mixing ratio of the first fibrous body and the second fibrous body is 1:0.5 to 1:1 and the twist number of the composite fibrous body is 20 to 60 T/m, The method for manufacturing a filter medium according to claim 6, wherein the first fibrous body and the second fibrous body are twisted together.