JP2002045612A - Filtration device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform stable filtration operation constantly by preventing a capturing material from becoming in an unnecessarily compact state during filtration operation. SOLUTION: Filter media 8 are constituted of a core strap 8a longer than the separation distance between a perforated plate 2 constituting a filter media supporting bed in a filtration chamber 1 and a structural material 3 of the filtration chamber facing the perforated plate 2 by a prescribed length and the capturing material 8b for turbid substances, which is projected to the peripheral side of the core strap. An adequate number of the filter media 8 is housed in the filtration chamber 1 and one end and another end of the core strap 8a are respectively fixed to the perforated plate 2 and the structural material 3, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filtration device used for trapping turbid substances from service water, wastewater and other raw water.

[0002]

2. Description of the Related Art For example, as described in Japanese Patent No. 2803041, one end is attached to a perforated plate constituting a filter medium support floor of a filtration chamber, and is made of a material which can be bent and deformed along the flow direction of raw water. There is a structure in which an appropriate number of filter media are housed in the filtration chamber.

[0003]

In the above conventional example, the filtering operation is performed with the free end side of the filter medium as the upstream side.
Since the free end is located upstream of the raw water, consolidation is likely to occur. Therefore, the thickness of the filter layer is small (thinned), so that the amount of trapped turbidity is reduced. In addition, there is a drawback that "habit" is attached to the filter, and it is difficult to return to the original state at the time of backwashing, and that the filter media are easily entangled at the time of the re-filtration operation, so that turbid substances are attached and so-called water flow is easily formed.

[0004]

A core string which is longer by a predetermined distance than a separation distance between a perforated plate constituting a filter medium support bed of a filtration chamber and a component of the filtration chamber opposed to the perforated plate; A filter medium is constituted by a turbid capturing material protruding to the peripheral side, an appropriate number of the filter materials are housed in the filtration chamber, one end of the core cord of the filter medium is provided on the perforated plate, and the other end is provided. Basically, each of the components is fixed to the component.

[0005] By providing a structure in which a trapping yarn omitting portion is provided near the perforated plate of the core string, the operation of scraping turbidity during backwashing is performed smoothly, and the filtering material is constituted by forming the constituent material of the upper perforated plate. Raw water can be uniformly injected into the filter, and a highly accurate filtration operation can be performed.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view showing one embodiment of a filtration device according to the present invention. In the drawing, reference numeral 1 denotes a filtration chamber, and the filtration chamber 1 has an inner wall 1A 'of the filtration tank 1A and a filter chamber 1A. The inside of the filter tank 1A is partitioned by a perforated plate 2 constituting a filter medium support floor and an upper perforated plate 3 installed in the filter tank 1A so as to be opposed to the perforated plate 2.

The filter tank 1A has an inlet 4 and an air vent 5 on the upper side, and an outlet 6 and a cleaning air pipe 7 on the lower side, respectively, and these are connected to the filter chamber 1.

An appropriate number of filter media 8,... Are accommodated in the filtration chamber 1, and raw water is filtered by the filter media 8,.

The filter medium 8 includes a core string 8a made of a material that can be bent and deformed along the flow direction (longitudinal direction) of the raw water, and the core string 8a.
Countless yarns 8b projecting radially on the circumference of
The lower end (on the drawing) of the core string 8a is fixed to the perforated plate 2 by the attaching means 9, while the upper end of the core string 8a is fixed to the upper porous plate 3 by the attaching means 9. It is housed in the filtration chamber 1 as described above.

The core string 8a is made of a twisted yarn made of polyester fiber and having a diameter of about 4 mm.
Although made of polyester fiber of μm, as a raw material, nylon, polyvinyl chloride, other resin fiber or vegetable fiber can be used, and it is needless to say that the yarn diameter need not be limited to the embodiment.

In the embodiment, a core string 8a and a catch thread 8b,
Are formed, and a core string 8a of the filter medium 8 is formed.
A core string 8a 'having the same material and the same diameter as the core string 8a is connected to the core string 8a by an appropriate connection means such as fastening and bonding, and the free end side of the core string 8a' is fixed to the upper porous plate 3 as described above. Although this is attached, this core string portion 8a 'from which the capture thread 8b is omitted may be provided integrally with the core thread 8a without additional connection, and the portion may be formed so as to omit the capture thread 8b.

In the embodiment, by adjusting the length of the core cord portion 8a 'from which the capture thread 8b is omitted, the compaction state of the filter medium 8, that is, the capture thread 8b,... During the filtering operation can be adjusted.

However, there is no inconvenience even if the catching thread 8b is provided in the core string 8a '.

By omitting the trapping yarn from the core string portion near the perforated plate 2, the washing property of the trapped yarn near the perforated plate 2 (during backwashing) is improved.

When raw water (untreated water) is injected through the inlet 4, the raw water passes through the filter medium 8 and is recovered as treated water through the outlet 6. ), The trapping yarns 8b,... Of the filter medium 8 tend to be compacted by the treated water. However, since one end of the core cord 8a supporting the trapping yarns 8b is fixed to the upper perforated plate 3, it is set in advance. The filtration operation is performed smoothly without consolidation.

When backwashing water is injected from the outlet 6 side, the core string 8a, which has been bent and deformed, has the side portion of the perforated plate 2 extending in the flow direction of the backwashing water, and the suspended matter trapped by the catching thread 8b. Is scraped off with backwash water and backwash operation is performed.

In the embodiment, the trapping yarns 8b,... Are not in contact with the upper perforated plate 3 due to the presence of the core string 8a 'in which the trapping yarns 8b are omitted even during backwashing.
As a result, the turbidity of the trapping yarn 8b on the upper porous plate 3 side is also smoothly scraped off.

The filter medium 8 of the embodiment has a core string 8a formed by attaching both ends of a capture thread 8b to a core string 8a so as to form a loop.
Are protruded on the peripheral side, but this is for convenience in manufacturing.

The present invention may be applied to a filter material provided with a spherical or flat trapping material for the core cord 8a or a linear trapping material as a whole having the core cord 8a as a core material. The present invention is suitably applied to a case in which a capturing material is provided on the peripheral side of the cord body fixed to the filter material, and the capturing material is in a compacted state during the operation of the filter material.

A comparison test between the conventional system and the suspension system according to the present embodiment is performed under the following conditions, and the results are shown.

[0021]

[Table 1]

Backwashing conditions Automatic backwashing is performed when the filtration duration of 5 hours has elapsed or when the pressure difference exceeds 0.05 MPa. (1) Filtration continuation time In the conventional method, each time the backwashing is repeated, the filtration continuation time becomes short, and the differential pressure exceeds 0.05 MPa in about one hour, and the backwashing is performed. On the other hand, in the suspension system, the filtration continuation time of 3 to 4 hours is maintained even in the continuous operation of 100 cycles, and it can be confirmed that the suppression of the differential pressure by the suspension system is effective. Further, the treated water quality of the suspension system and the conventional system was equivalent, and the turbidity removal rate was almost 100%. There is no deterioration in treated water quality due to the suspension method.

[0023]

[Table 2]

(2) Improvement in Detergency Change in Initial Filter Layer Thickness Table 3 shows the filter layer thickness (filter layer height) immediately after the backwashing and immediately after the start of filtration. In the conventional system, it has been reduced to about 750 mm, but in the suspension system, it has been reduced to just under 900 mm, and the cleaning efficiency has been improved.

[0025]

[Table 3]

Changes in Initial Differential Pressure Table 4 shows the differential pressure immediately after the end of backwashing and immediately after the start of filtration.
In the conventional method, the initial differential pressure rises sharply, but in the suspension method, the initial differential pressure rise is very slow. Again, it can be seen that the cleaning efficiency has increased.

[0027]

[Table 4]

[0028]

The present invention has the configuration described above,
By appropriately lengthening the core cord with respect to the separation distance between the perforated plate and the constituent material of the filtration chamber, it is possible to prevent the capturing material from becoming unnecessarily compacted at the time of the filtration operation.
The filtration operation can always be performed in a stable state, and backwashing can be performed smoothly because the trapping material does not have a habit due to compaction.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Filtration chamber 2 Perforated plate 3 Upper perforated plate 8 Filter material 8a Core string 8b Capture thread

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01D 29/38 580H (72) Inventor Takuya Hosoya 1-13-9 Tagawakita, Yodogawa-ku, Osaka-shi, Osaka (72) Inventor Hiroshi Adachi 1-13-9 Tagawakita, Yodogawa-ku, Osaka-shi, Osaka

Claims (3)

[Claims] 1. A core string that is longer than a separation distance between a perforated plate constituting a filter medium support bed of a filtration chamber and a component of the filtration chamber facing the perforated plate, and protrudes to the peripheral side of the core string. A filter medium is configured with the turbid capturing material, and an appropriate number of the filter materials are housed in the filtration chamber, and one end of the core string of the filter material is provided on the perforated plate.
A filter device, the other end of which is fixed to each of the components. 2. The filtering device according to claim 1, wherein a trapping yarn omitting portion is provided near the perforated plate of the core string. 3. The component according to claim 1, wherein the component is an upper perforated plate.
Or the filtration device according to 2.