JP2757956B2 - Transfer type continuous sand filter and its construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-module type continuous transfer system for water treatment for upgrading and reusing effluent such as sewage drainage, domestic wastewater, industrial wastewater, etc., and pretreatment of water supply and sewerage. The present invention relates to a sand filtration device (hereinafter, simply referred to as a sand filtration device) and a method of installing the same.

[0002]

2. Description of the Related Art A sand filter is an excellent continuous sand filter capable of simultaneously performing filtration of raw water and washing of sand as a filter medium, and is widely used for water treatment. Originally, the package type of a single filtration tank for the treatment of a relatively small amount of water was mainly used, but as its excellent performance has been recognized, the demand for a large amount of treated water has increased. In order to respond to this, a multi-module type combining a plurality of filtration tanks has been developed, and constructions up to several tens of modules have been constructed.
Specific examples of this type of sand filtration device, including package type,
For example, it is described in detail in JP-B-56-51808.

[0003] The structure of this type of sand filtration device will be briefly described with reference to the drawings by taking an example to facilitate understanding of the present invention. FIG. 4 is a longitudinal sectional view of an example of a single filtration tank shown for explaining the structure of the sand filtration device. The filter bed 22 at the upper part of the filter tank 21 is formed by a cylindrical wall 24, and the lower part is formed in a cone shape to facilitate the movement of sand as a filter medium (hereinafter, this portion is referred to as a cone portion 23). ). Regarding the shape of the filtration bed 22, a package type has many cylinders, but a multi-module type has a mainstream polygon tube which is advantageous in wall strength. Accordingly, the shape of the cone-shaped portion 23 is an inverted cone or an inverted polygonal pyramid.
In the multi-module type, since a plurality of filtration tanks 21 are arranged in close contact with each other, the wall 24 at the boundary between the respective filtration tanks 21 is formed.
The filter bed 22 is generally formed by leaving only the wall 24 surrounding the entire filtration tank and removing the wall 24 that is a boundary between the respective filtration tanks 21. However, the cone portion 23 of each filtration tank is left.

[0004] The sand of the filter medium descends from the filter bed 22 to the cone-shaped portion 23, is sucked by the air lift 25 from a portion corresponding to the top of the lowermost cone, and is mixed and washed with air and water while rising. Further, the backwash wastewater and the sand are separated by the separator 26, and the sand is washed by the sandwasher 27 in the counterflow with the filtered water, and is returned to the filter bed 22 again. Distributed umbrella 3
0 uniformly disperses the sand in the cone-shaped portion 23. The raw water is supplied to the lower part of the filter bed 22 from a raw water supply pipe 28, passes through the filter bed 22, is filtered, overflows from a collecting trough 29, and is taken out as filtered water.

[0005] Therefore, in a sand filtration device, it is important to determine the filtration performance by circulating the sand uniformly, washing and regenerating the sand. In order for the sand of the filter bed to be evenly and uniformly sucked by the air lift, the cone-shaped portion needs to be manufactured with high dimensional accuracy. If the accuracy is not good, a drift occurs in the flow of the sand, and sand that cannot be washed is formed. Conventionally, in the package type, there was no particular problem because the filtration tank was made with high accuracy using metal or fiber reinforced plastic (FRP) or the like. However, the multi-module type requires a large filter tank, so that the entire filter tank, including the cone-shaped part, was constructed of concrete so that it would be easy to construct on site, low in cost, and advantageous for large tanks. However, it was found that it was not possible to finish to the required accuracy in concrete construction, and that it was difficult to clean the sand, and the present inventors examined and implemented various sand filtration devices as a countermeasure.

FIG. 5 is a schematic plan view showing one example, and FIG.
Is a schematic longitudinal sectional view thereof. In this example, each filtration tank 31
Concrete tank 3 surrounding all filtration tanks by removing walls between them
2 is provided as an outer wall of a filtration bed 33, and a cone-shaped portion 34 made of a corrosion-resistant material such as stainless steel is attached to a lower portion thereof. The cone portion 34 and the concrete tank 3
Raw water is supplied from a pressure regulating tank 36 to a space 35 between the two bottoms and is filled. This raw water is guided to a filtration bed 33 through a raw water supply pipe 37 that penetrates the cone-shaped portion 34, and is filtered. However, in this device, the concrete tank 32
Solid matter in the raw water accumulates on the bottom (38), and it rots and deteriorates the water quality, promotes corrosion of the cone-shaped portion 34, and has a problem that a large repair cost is required in a short time.

FIG. 7 is a schematic longitudinal sectional view for explaining another example. This plan view is omitted because it is similar to FIG. In this embodiment, in order to solve the problem of the above-described example, a raw water supply pipe 39 is provided from the pressure regulating tank 36 to the raw water supply pipe 37. Since the raw water is not directly injected into the space 35, the cone-shaped portion 34 is prevented from being corroded from the outside, but the total weight of sand and water such as the filter bed 33 is applied to the cone-shaped portion 34. It takes a certain amount of strength to withstand this, resulting in a considerable increase in cost. Also, since the water must not leak, the cone-shaped portion 3
The installation and piping of No. 4 required advanced structure and construction, and caused problems in terms of technology and cost.

FIG. 8 is a longitudinal sectional view of a sand filter proposed to solve the above problem. In this example, a concrete convex portion 45 is provided in advance at the bottom of the concrete tank 42 so as to fit into the cone-shaped portion 44, and a metal or FRP cone-shaped portion 44 is fitted into the concave portion thereof. The raw water supply pipe 46 is inserted from the upper part to the lower part of the filtration bed 43. Since the concrete tank 42 receives the load of sand or water from the filter bed 43 or the like, the strength of the cone-shaped portion 43 may not be so large. However, in order to achieve the effect, in order to fit well, the construction accuracy of the bottom of the concrete tank 41 must be high,
To do that in concrete work was not possible as a practical matter.

In addition, JP-A-51-11624, JP-A-58-160285, and JP-B-52-9
No. 055, Japanese Utility Model Publication No. 1-1327, Japanese Unexamined Patent Publication No.
Japanese Patent No. 268976 discloses a construction method and a composite panel in which concrete is cast using a formwork or a concrete plate as a formwork in which a surface material and concrete are integrated, and the formwork and the cast concrete are integrated. Joining to form, form and integrate with concrete, using a framing frame processed to the curved surface, bend a thin metal plate on site, integrate with concrete, and then remove the framing method The use of a mold is described. However, the above-mentioned problems cannot be solved by the construction method using these simple disposable frames. To construct a large number of cone-shaped parts like a multi-module, for example, a formwork in which a thin surface material and concrete are integrated has a large own weight, transporting, site assembly cost is excessive, and a cone-shaped The parts cannot be constructed with the required precision, and it is extremely difficult to bend the material that forms the cone-shaped part on site, and to assemble and connect it accurately with the construction method that uses the framing frame. In the case of a plastic plate, it cannot be used.

As described above, a sand filter for improvement has been proposed and implemented, or the use of various conventional construction methods has been studied. However, an economical filter which can withstand a large load and can be used for a long period of time is considered. It was not possible to find a suitable sand filtration device and a method capable of constructing the cone-shaped part of the multi-module with required accuracy.

[0011]

The present inventor has further made use of the above experience, and has a required accuracy so as not to hinder the circulation of sand and can be used for a long period of time. For the purpose of providing the method of construction and its construction, we examined mainly the structure and construction of the cone-shaped part.

[0012]

As a result, in order to solve these problems, in a multi-module type transfer type continuous sand filtration device, a cone-shaped portion at a lower portion of a filtration tank is constituted by a metal plate or a fiber-reinforced plastic plate, and The cone-shaped part is used as a mold, and concrete is directly cast on the outer periphery of the cone-shaped part, thereby integrating the cone-shaped part and the cast concrete to form the bottom of the filtration tank. A multi-module type transfer type continuous sand filtration device characterized by this is completed.

Further, according to the present invention, in the construction of the multi-module type transfer type continuous sand filtration device, the outer wall 2 is constructed, and the constructed outer wall 2 is accurately formed of a metal plate or a fiber reinforced plastic plate. The cone-shaped portion 4 is attached, the attached cone-shaped portion 4 is used as a formwork for casting concrete, concrete 5 is cast between the cone-shaped portion 4 and the outer wall 2, and the concrete 5 and the cone-shaped portion are cast. 4. A method for constructing a multi-module type transfer-type continuous sand filtration device, wherein the method is integrated with, and adhered to and joined to, is completed.

Further, in the present invention, in the construction of a multi-module type transfer type continuous sand filtration device, a precisely configured cone-shaped portion 4 is fixed, and the fixed cone-shaped portion 4 is used as a mold, and concrete around the cone is used. Lower part of the outer wall 2,
And concrete 5 is cast between the cone-shaped portion 4 and the lower portion of the outer wall 2, and the concrete 5 and the cone-shaped portion 4 are integrally adhered and joined to each other, and the upper portion of the outer wall 2 is constructed. The construction method of the multi-module type continuous sand filtration device was completed.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings showing an embodiment of the present invention. FIG. 1 is a front view including a partial cross section of an embodiment of a sand filtration device according to the present invention, FIG. 2 is a plan view including a partial cross section, and FIG.
FIG. In the present embodiment, the filtration bed 3 of each filtration tank 1 is an octagonal tube, four units are arranged in a line, the walls between the filtration beds 3 are removed, and there is no partition. A concrete wall is provided as the outer wall 2 surrounding all the filtration tanks 1. A metal or FRP cone-shaped portion 4 is joined to the lower part of the filtration bed 3 for each filtration tank 1, and concrete 5 is cast around each cone-shaped portion 4 to be integrated with the cone-shaped portion 4. It is closely bonded.

The shape of the cone-shaped portion 4 is such that a plurality of funnel-shaped polygonal pyramids (octagonal pyramids in the present embodiment) or cones are arranged such that the bottom surface (actually opening upward) is the same plane. A metal plate or FRP
It is composed of plates. As the metal plate, a stainless steel plate, a carbon steel plate whose surface is rust-proofed or coated with a rust-proof paint, or the like is preferable, and an aluminum plate or the like may be used. As the FRP, a polyester resin or an epoxy resin reinforced with a water-resistant and economical glass fiber is used. The cone-shaped portion 4 may be formed in advance in the factory as a whole, or may be assembled by welding or bonding at a construction site. Unlike the concrete construction, if these materials are used, it is possible to easily assemble them to a predetermined dimensional accuracy. The cone-shaped portion 4 needs to have a strength necessary for placing the concrete 5 and a strength that does not cause distortion.

Now, a concrete means for placing the concrete 5 and tightly bonding it with the cone-shaped portion 4 will be described. In addition, although concrete is used for the outer wall 2 surrounding all the filtration tanks 1 in this embodiment,
It is not limited to concrete, but may be a tank made of metal or plastic. However, for large equipment, concrete walls that are easy to maintain and require no equipment cost are preferred. An example of a specific construction method is that a cone formed by firstly constructing the outer wall 2, at least a lower portion corresponding to the cone-shaped portion 4, and accurately forming a metal plate or a fiber-reinforced plastic plate inside the constructed outer wall 2. Attach part 4.
The mounted cone-shaped portion 4 is used as a formwork for casting concrete, and concrete 5 is cast directly around the cone-shaped portion 4 so that the concrete 5 and the cone-shaped portion 4 are integrated and adhered to each other. And join.

Another example is to fix a precisely formed cone-shaped portion 4 by any method, use the fixed cone-shaped portion 4 as a formwork, and surround the lower part of the concrete outer wall 2 and the concrete 5 around it. The concrete 5 and the cone-shaped portion 4 can also be integrally adhered and joined together by casting and then constructing the upper part of the outer wall 2. In any case, a precisely configured cone-shaped portion 4
However, when the concrete 5 is cast, it functions as a form frame, and after the concrete 5 is solidified, the concrete 5 comes into close contact with, joins, and is integrated. Further, the concrete 5 can be in close contact with and joined to the concrete outer wall 2. Since the cone-shaped portion 4 is in close contact with, bonded to, and integrated with the concrete 5 cast, the load applied to the cone-shaped portion 4 is supported by the concrete 5, and the required strength of the cone-shaped portion 4 itself is small. Is small.

In this embodiment, the raw water is supplied from the raw water supply pipe 6 above the filtration tank 1 to the filter bed 3 through the disperser 7. However, as described above, a supply pipe may be provided in the lower part of the filtration tank 1 and supplied from the lower part. The same applies to the supply of air used for the air lift 8. A trough 9 is provided at the upper part of the filtration tank, from which the filtered water overflows and is taken out. The sand of the filtration bed 3 uniformly descends to the cone-shaped portion 4 whose inner wall is made of metal or FRP with high precision, is sucked by the air lift 8, is washed through the separator 10 and the sand washer 11, and is washed. Returned to 3. Known structures can be used for these structures.

[0020]

According to the sand filter of the present invention, since metal or FRP is used for the cone portion, even a huge device can be manufactured with high accuracy by selecting an appropriate place.
A cone-shaped portion manufactured with high accuracy is used as a concrete formwork, and concrete is directly poured around the concrete-shaped portion, and the concrete and the cone-shaped portion are closely adhered and joined in a wide area. For this reason, the upper sand or water load applied to the cone-shaped part is supported by concrete on the entire surface to be joined to the concrete, so high strength is not required for the cone-shaped part, so members can be saved and there is a concern that the load will be distorted by the load. Nor. In addition, since the cone-shaped portion having high dimensional accuracy is formed, the sand on the filtration bed is uniformly and smoothly circulated and washed, so that the function as a continuous filtration device can be sufficiently exhibited. Further, since the construction of the apparatus itself can be simplified, the construction period is short, and the apparatus cost is saved. Since the cone-shaped portion is integrated with the concrete, there is no water leakage due to corrosion, and there is no problem in precision associated with concrete construction.

[Brief description of the drawings]

FIG. 1 is a front view including a partial cross section of an embodiment of a sand filtration device according to the present invention.

FIG. 2 is a plan view including a partial cross section of FIG. 1;

FIG. 3 is a sectional view taken along line AA ′ of FIG. 2;

FIG. 4 is a longitudinal sectional view of an example of a single filtration tank shown for explaining the structure of the sand filtration device.

FIG. 5 is a schematic plan view showing an example of an improved sand filtration device.

6 is a schematic longitudinal sectional view of the device shown in FIG.

FIG. 7 is a schematic longitudinal sectional view for explaining another example of the improved sand filtration device.

FIG. 8 is a schematic longitudinal sectional view for explaining another example of the improved sand filtration device.

[Explanation of symbols]

1: Filtration tank 2: Outer wall 3: Filtration floor 4: Cone portion 5: Concrete 6: Raw water supply pipe 7: Disperser 8: Air lift 9: Trough
10: Separator 11: Sand washer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B01D 24/36

Claims (3)

(57) [Claims] In a multi-module type continuous sand filtering apparatus, a cone-shaped portion at a lower portion of a filtration tank is constituted by a metal plate or a fiber-reinforced plastic plate, and the cone-shaped portion is directly used by using a mold. A multi-module transfer type, wherein concrete is cast on the outer periphery of the cone-shaped portion, thereby integrating the cone-shaped portion and the cast concrete to form the bottom of the filtration tank. Continuous sand filtration device. 2. In the construction of a multi-module type transfer type continuous sand filtration device, an outer wall 2 is constructed, and a cone-shaped portion 4 accurately formed of a metal plate or a fiber reinforced plastic plate is formed in the constructed outer wall 2. The attached cone-shaped portion 4 is used as a formwork for casting concrete, concrete 5 is cast between the cone-shaped portion 4 and the outer wall 2, and the concrete 5 and the cone-shaped portion 4 are integrated. Close contact,
A method for constructing a multi-module type transfer type continuous sand filtration device, characterized by joining. 3. In the construction of a multi-module type transfer type continuous sand filtration device, a precisely configured cone-shaped portion 4 is fixed, and the fixed cone-shaped portion 4 is used as a formwork. Concrete 5 is poured between the lower part of the outer wall 2 and the cone-shaped part 4 and the lower part of the outer wall 2 so that the concrete 5 and the cone-shaped part 4 are integrally adhered and joined together, and the upper part of the outer wall 2 is constructed. The construction method of the multi-module transfer type continuous sand filtration device.