JP2001070710A - Filter apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter apparatus hard to generate clogging and capable of obtaining the planar uniformity of sufficient flow rate distribution at a time of backwashing. SOLUTION: In a filter apparatus wherein unfiltered raw water is added to the filter medium bed arranged on a support bed from above and passed through the filter medium bed and the support bed to obtain filtered clean water under the support bed, as the support bed, a perforated plate obtained by heating and welding a large number of spherical synthetic resin particles while keeping them almost spherical is used. The diameter of the synythetic resin particles is set to about 4 mm and the average void size of the perforated plate is set to about 1,000 μm and the void ratio thereof is set to about 33%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter, and more particularly, to an improvement in a lower water collecting portion.

[0002]

2. Description of the Related Art Filtration devices are incorporated in some water treatment facilities in various fields such as water treatment, waste water treatment, hard water softening, pure water production, and fine chemicals.

FIG. 2A is a plan view of a schematic configuration diagram of a filtration pond in a water supply facility showing an example of use of such a filtration mechanism, and FIG. 2B is a partial sectional view thereof. In the figure, unfiltered raw water uniformly flows into a filtration area 3 from a raw culvert 1 through a raw water inlet 2. The filtration area 3 is divided into a plurality of independent sections by a division partition plate 4. Filtration area 3
Each of the sections is provided with a filter medium layer 5 and a support floor 6 for supporting the filter medium layer 5. As the filter medium layer 5, for example, a layer in which sand and gravel are arranged in layers is used.

[0004] Raw water becomes purified water filtered through a filter medium layer 5 and a support floor 6, and is provided with a water purification chamber 7, a water purification pipe 8 and a backwash valve 9.
Through the water purifier 10. On the other hand, a traveling platform 11 for cleaning the filter medium layer 5 and the support floor 6 is movably disposed in the upper part of the filtration area 3 in each section. A control panel 12, a drain pump 13, a front washing pump 14, a back washing pump 15, a switching valve 16, and the like are provided above the traveling platform 11. A cleaner box 17 is hung below the traveling platform 11 so as to fit into each section of the filtration area 3. A front wash pipe 18 is provided inside the cleaner box 17 on the side facing the filter medium layer 5, and a water collecting pipe 19 is provided above the front wash pipe 18. The washing pipe 18 is connected to the washing pump 14 via the switching valve 16. Also,
The switching valve 16 is connected to the drain gutter 20. Water collecting pipe 19
Is also connected to a drain gutter 20 via a drain pump 13. The backwash pump 14 is connected to the backwash pump 15 and to the backwash valve 9. Drain gutter 20 drains 2
1 connected. The water purifier 10 is connected to a water purifier 22.

FIG. 3 is an explanatory view of the cleaning operation, and the same parts as those in FIG. 2 are denoted by the same reference numerals. Washing is performed for each section of the filtration area 3. That is, in cleaning, the traveling platform 11 is stopped immediately above the target section of the filtration area 3, the drainage pump 13, the front washing pump 14, and the backwash pump 15 are operated, and the switching valve 16 is moved to the front washing side. Switch. The water discharged from the backwash pump 15 is branched in two directions. One of the branched discharge waters is pressurized by a surface-washing pump 14 and then added to a surface-washing pipe 18 through a switching valve 16, and is applied to the surface of the filter medium layer 5 as surface cleaning water for cleaning the surface of the filter medium layer 5. It is injected. The other of the branched discharge water flows back through the water purification pipe 8 through the backwash valve 9, from the water purification chamber 7 side to the support floor 6 and the filter medium layer 5.
The backwash will be the reverse wash water.

[0006] The water that has washed the filter medium layer 5 in this manner is collected by the drainage pump 13 through the water collecting pipe 19 and discharged to the drainage gutter 20. When the washing operation shown in FIG. 3 is completed, the operations of all the pumps are stopped to stabilize the filter medium layer 5. Thereafter, as shown in FIG. 4, only the front washing pump 14 is operated, and the switching valve 16 is switched to the drain side. In addition,
In FIG. 4, the same parts as those in FIG. 2 are denoted by the same reference numerals. As a result, the filtered drain water after washing flows back through the discharge pipe of the back washing pump 15 and is discharged to the drain gutter 20 via the front washing pump 14 and the switching valve 16. Note that these series of operations are automatically performed, and when the washing step and the filtration / draining step of a certain section are completed, the traveling platform 11 moves to the next section.

[0007] By the way, as the supporting bed 6 in such a conventional filtering apparatus, a perforated plate made of ceramics in which molten alumina is annealed has been used.

[0008]

However, such a conventional perforated plate is liable to be clogged due to a large variation during molding, and has a problem in that a flow distribution is required when backflow cleaning is performed together with the uneven surface. There is a problem that uniformity is difficult to obtain.

Here, if the cleaning is uneven in a plane,
Since water passes only through the well-washed portion during the filtration, a portion having an extremely high filtration speed is generated, and the insufficiently-washed portion gradually becomes clogged and the filtering function is reduced.

The present invention has been made in view of such a problem of the conventional perforated plate. The object of the present invention is to prevent clogging and to obtain sufficient planar uniformity of flow distribution during backwashing. To provide a filtration device.

[0011]

Means for Solving the Problems According to the first aspect of the present invention which achieves the above object, the present invention relates to a filter medium layer and a support bed, wherein unfiltered raw water is added from above a filter medium layer disposed on a support bed. And a filter device configured to wash the filter medium layer by applying pressurized washing water to the filter medium layer from the lower part of the support floor while obtaining purified water filtered at the lower part of the support floor by passing through the support bed. The floor is characterized by using a porous plate obtained by heating and welding a large number of spherical synthetic resin particles in a state where they are substantially spherical.

In such a perforated plate, since a large number of spherical synthetic resin particles are heat-welded while maintaining substantially spherical shapes, there is less variation during molding as compared with a conventional perforated plate made of ceramics. The target surface has high smoothness and is not easily clogged. In the backflow cleaning, a sufficient planar uniformity of the flow rate distribution can be obtained.

According to a second aspect of the present invention which achieves the above object, in the filtration apparatus according to the first aspect, the synthetic resin particles are styrene / butadiene copolymer resin. .

Here, the styrene-butadiene copolymer resin shows extremely stable results in various chemical resistance tests, and is not affected at all by the chlorine agent used for sterilizing tap water. Therefore, it is suitable as a support floor for a filtration device.

According to a third aspect of the present invention, which achieves the above object, in the filtration apparatus according to the first aspect, the diameter of the synthetic resin particles is approximately 4 mm.

[0016] Further, according to a fourth aspect of the present invention, which achieves the above object, in the filtration apparatus according to the first aspect, the perforated plate has an average pore diameter of about 1,000 µm.
The porosity is approximately 33%.

Here, the average pore diameter of the perforated plate is 1,000 μm.
Since m is larger than the minimum diameter of the filter medium layer of 0.2 mm, clogging does not easily occur and uniform and effective filtration performance can be obtained.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an enlarged configuration diagram of a perforated plate used as a support floor in the present invention. In the figure, a large number of spherical synthetic resin particles are three-dimensionally heat-welded while maintaining a substantially spherical shape. In addition, as the synthetic resin particles, for example, a styrene / butadiene copolymer resin is used. Specifically, only a spherical styrene / butadiene copolymer resin having a diameter of about 4 mm is filled in a mold, and no additive is used. Allow to dissolve.

As a result, the spherical styrene / butadiene copolymer resin is heated and welded while maintaining a substantially spherical shape, and a porous plate having an average pore diameter of about 1,000 μm and a porosity of about 33% is obtained. Molded.

Here, the styrene-butadiene copolymer resin shows extremely stable results in various chemical resistance tests, and is not affected at all by the chlorine agent used for sterilizing tap water. Absent.

Further, the styrene-butadiene copolymer resin does not contain any 67 kinds of chemical substances designated by the Environment Agency suspected of having an extrinsic endocrine disrupting action, and generates dioxin when burned alone. Since it does not contain any halogenated compounds, its safety is extremely high in environmental aspects.

Total length 994 mm, total width 295 mm, thickness 2
In order to check the uniformity of the porousness of the 5 mm perforated plate, the perforated plate is divided into three in the longitudinal direction and the length is adjusted to 30 cm.
The air permeation rate (ft ³ / ft ² / min) at a pressure of 50 mm · aq was measured by setting cm × 28 cm. As a result, for the ten test pieces, the measurement result of the average value 214 was obtained at the minimum value 206 to the maximum value 223, and the variation was ± 10% or less. Each of these test pieces could withstand a breaking strength of 150 kgf or more. This mechanical strength is sufficiently satisfactory as a filtration system for water supply.

Next, the perforated plate was disposed in a flow system through which tap water at a water temperature of 8 ° C. flows, and the pressure loss was measured by measuring the pressure before and after the perforated plate. Resistance (filtration resistance) is 40 mm, specific resistance (filtration resistance) at a filtration speed of 150 m / day is 50 mm, filtration speed is 1
The specific resistance (filtration resistance) at 80 m / day is 60 m
m. In addition, the specific resistance value is the perforated plate and the sand layer thickness 20
This corresponds to the total value of the pressure loss of 0 mm.

As for the backwashing property, a quartz sand layer having an effective diameter of 0.6 mm and a uniformity coefficient of 1.4 or less laminated on a perforated plate at a thickness of 600 mm was used.
When the backwash flow rate is 0.6 (m ³ / m ² / min), the expansion of the sand layer is 5 to 6 cm, the expansion rate is 8.3 to 10.0%, and the back wash flow rate is 0.7 (m ³ / m ² / min). / M ² / min), the expansion of the sand layer is 8 to 10.0 cm and the expansion rate is 13.3 to 16.
6%, and the average expansion rate was 9.1 to 14.9%.

The supporting floor having such a structure is the same as the lower water collecting apparatus of the "Guidelines for Water Supply Facilities Design and Explanation" except that the shape of the perforated plate only changes in material. ,
It sufficiently satisfies the porosity, mechanical strength and the like.

Further, with such a configuration, it is possible to satisfy the condition of uniformity of flow distribution at the time of backwashing, which is important for the lower water collecting portion, and to obtain uniformity at the time of collecting filtered water.

Further, the surface of the support floor is smooth, the coefficient of friction loss is small, and the pressure loss is small. In addition, clogging is unlikely to occur, and characteristics do not vary.

The application is not limited to the filtration device for water supply, but is also suitable for various filtration devices.

[0029]

According to the present invention described above, it is possible to provide a filtration device which is less likely to cause clogging and which can obtain a sufficient uniform flow distribution in the case of backwashing.

[Brief description of the drawings]

FIG. 1 is an enlarged configuration diagram of a perforated plate used as a support floor in the present invention.

FIG. 2 is a schematic configuration diagram of a filtration pond in a water supply facility showing an example of use of the filtration device.

FIG. 3 is an explanatory diagram of a cleaning operation.

FIG. 4 is an explanatory diagram of a filtration water distribution operation.

[Explanation of symbols]

 5 Filtration layer 6 Supporting bed (styrene-butadiene copolymer resin porous plate)

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01D 29/08 540A

Claims (4)

[Claims] 1. A filter device wherein unfiltered raw water is added from above a filter medium layer disposed on a support bed and passes through the filter medium layer and the support bed to obtain purified water filtered at a lower portion of the support bed. A filtration plate characterized by using a porous plate obtained by heating and welding a large number of spherical synthetic resin particles while maintaining substantially spherical shapes. 2. The filter according to claim 1, wherein the synthetic resin particles are a styrene / butadiene copolymer resin. 3. The filter according to claim 1, wherein the diameter of the synthetic resin particles is approximately 4 mm. 4. The porous plate has an average pore diameter of about 1,000.
2. The filter according to claim 1, wherein the porosity is about 33%.