De-dusting device

Abstract

To provide a clarifier capable of reducing cost.SOLUTION: A clarifier 1 includes a filtration tank 11, a partition 12 that divides the filtration tank 11 into a first chamber 11a on the raw water side and a second chamber 11b on the treated water side, a first filter group 13 which is installed in the first chamber 11a and has a plurality of first filters 13a whose secondary side is connected to the second chamber 11b, a second filter group 17 installed in the first chamber 11a and having a plurality of second filters 17a, a connection pipe 14 for merging discharge parts 53 of the plurality of second filters 17a, and a pipe 16 for connecting the connection pipe 14 and the second chamber 11b and having a flow passage resistance larger than that of the second chamber 11b.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a clarification device for filtering water. [Background technology]

[0002] A clarification device that uses a filter to filter water has been known for some time. In such a clarification device, a plurality of cylindrical filters are arranged in a filtration tank, and a flow path through which raw water to be filtered flows is separated from a flow path through which filtered treated water flows. The raw water is treated by passing through the filters, and the treated water is supplied to the secondary side. In the clarification device, raw water is supplied from the upper part of the filtration tank and treated water is discharged from the lower part of the filtration tank.

[0003] In this type of turbidity removal device, raw water flows in through the base of the filter, where filtration loss is lowest, and so filter clogging progresses from the base of the filter upward. However, as filter clogging progresses, it leads to a decrease in filtration flow rate and an increase in filtration loss. For example, Figure 12 shows the relationship between filtration loss and the cumulative flow rate of raw water passing through the filter. Figure 12 also shows the change in filtration loss when eight 10-inch filters with a nominal membrane filtration diameter of 0.1 μm are placed in a filtration tank and raw water with a turbidity of 10 degrees is filtered at a treatment filtration flow rate of 15 L / min.

[0004] As can be seen from Figure 12, filtration loss increases as the cumulative flow rate of raw water passing through the filter increases. This means that the filter needs to be replaced before it becomes completely clogged, which increases the frequency of filter replacement and results in higher running costs.

[0005] Filter clogging can be monitored by detecting the filtration flow rate and the differential pressure as filtration loss. However, as filter clogging progresses, the filtration flow rate and filtration loss change in a quadratic curve. Delaying filter replacement can lead to a significant drop in filtration flow rate and an increase in differential pressure, so it is necessary to replace the filter when the filter is still not significantly clogged.

[0006] Therefore, a technology is known in which multiple filters are installed in parallel, and high-load filtration is performed by setting a high filtration flow rate for only selected filters, and the filtration flow rate of low-load filters is controlled based on the amount of water passed through the high-load filters until the quality of the treated water deteriorates (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 6288319 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the above-mentioned technology requires accessories such as a water quality measuring instrument and a control device. In addition, when the filters become clogged, all the filters must be replaced. This results in problems such as high manufacturing costs and running costs for the clarification device.

[0009] Therefore, an object of the present invention is to provide a clarification device that can reduce costs. [Means for solving the problem]

[0010] A clarification device according to an embodiment of the present invention includes a filtration tank, a partition plate that separates the filtration tank into a first chamber on the raw water side and a second chamber on the treated water side, a first filter group that includes a plurality of first filters that are provided in the first chamber and have a secondary side connected to the second chamber, a second filter group that is provided in the first chamber and has a plurality of second filters, a connecting pipe that joins the outlets of the plurality of second filters, and a connecting pipe that connects the connecting pipe to the second chamber. Distribution a tube; The partition plate has a first opening for connecting the piping and a plurality of second openings for fixing the first filter, the discharge portion of the first filter is inserted into the second opening, one end of the piping is connected to the connecting pipe, and the other end of the piping is fixed to the first opening. . [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a clarification device that can reduce costs. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a side view showing the configuration of a clarification device according to an embodiment of the present invention. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. 2 is a perspective view showing the configuration of the clarification device with the configuration of the filtration tank partially omitted. [Figure 5] FIG. 2 is a perspective view showing the configuration of the clarification device with the configuration of the filtration tank omitted. [Figure 6] FIG. 3 is a plan view showing the configuration of the partition plate of the clarification device. [Figure 7] FIG. 3 is a cross-sectional view showing the configuration of a first filter group and a connecting portion of the clarification device. [Figure 8] FIG. 3 is a side view showing the configuration of a connecting pipe of the clarification device. [Figure 9] FIG. [Figure 10] FIG. 3 is a plan view showing the configuration of a plate of the clarification device. [Figure 11] FIG. 2 is a perspective view showing the piping configuration of the clarification device. [Figure 12] 10 is a graph showing the relationship between the integrated flow rate and the filtration loss in a conventional clarification device. DETAILED DESCRIPTION OF THE INVENTION

[0013] The configuration of a clarifier 1 according to one embodiment of the present invention will be described below with reference to FIGS. 1 to 11. FIG. 1 is a side view showing the configuration of the clarifier 1 according to one embodiment of the present invention, and FIG. 2 is a top view showing the configuration of the clarifier 1. FIG. 3 is a cross-sectional view showing the configuration of the clarifier 1. FIG. 4 is a perspective view showing the configuration of the clarifier 1 with the filtration tank 11 partially omitted. FIG. 5 is a perspective view showing the configuration of the clarifier 1 with the filtration tank 11 omitted. FIG. 6 is a plan view showing the configuration of the partition plate 12 of the clarifier 1, and FIG. 7 is a cross-sectional view showing the configuration of the first filter group 13 and connecting pipe 14 of the clarifier 1. FIG. 8 is a side view showing the configuration of the connecting pipe 14, and FIG. 9 is a plan view showing the configuration of the connecting pipe 14. FIG. 10 is a plan view showing the configuration of the plate 15 of the clarifier 1, and FIG. 11 is a perspective view showing the configuration of the piping 16 of the clarifier 1.

[0014] 3, the clarification device 1 includes a filter tank 11, a partition plate 12, a first filter group 13, a connecting pipe 14, a plate 15, piping 16, a second filter group 17, and fastening members 18. The clarification device 1 clarifies raw water supplied from the primary side into the filter tank 11 using the first filter group 13 and the second filter group 17, and discharges the treated water to the secondary side.

[0015] As shown in Figure 3, a partition plate 12 is provided inside the filtration tank 11. The internal space of the filtration tank 11 is divided by the partition plate 12 to form a first chamber 11a through which raw water flows and a second chamber 11b through which treated water flows.

[0016] 1 to 3, the filtration tank 11 includes, for example, a raw water-side filtration tank 21 and a treated water-side filtration tank 22. The filtration tank 11 accommodates a partition plate 12, a first filter group 13, a connecting pipe 14, a plate 15, piping 16, a second filter group 17, and fastening members 18 therein.

[0017] The raw water side filtration tank 21 comprises a cylindrical first body 21a, a cover 21b covering the upper end of the first body 21a, a raw water inlet 21c provided in the first body 21a, and flanges 21d provided on both ends of the first body 21a.

[0018] The cover 21b is formed in a dome or hemisphere shape, and has a flange 21b1 at its end that is fixed to the flange 21d of the first body 21a.

[0019] The raw water inlet 21c is provided in the first body 21a. The raw water inlet 21c is formed, for example, in a tubular shape having a flange 21c1. The raw water inlet 21c is connected to a pipe on the water supply source side (primary side) that supplies raw water.

[0020] The treated water side filtration tank 22 comprises a cylindrical second body 22a, a bottom body 22b covering the lower end of the second body 22a, a treated water outlet 22c provided in the second body 22a, and a flange 22d provided at the upper end of the second body 22a.

[0021] The axial dimension (height) of second body 22a is smaller than the axial dimension (height) of first body 21a. That is, the volume of first chamber 11a of filtration tank 11 is larger than the volume of second chamber 11b. Bottom body 22b closes the lower end of second body 22a.

[0022] Treated water outlet 22c is provided in second body 22a. Treated water outlet 22c is formed, for example, in a tubular shape having flange 22c1. Treated water outlet 22c is connected to a pipe on the supply destination side (secondary side) that supplies treated water.

[0023] The partition plate 12 divides the inside of the filtration tank 11 into two chambers, a first chamber 11a and a second chamber 11b. The partition plate 12 is formed, for example, in a disk shape, and is fixed by being sandwiched between a flange 21d of the first body 21a and a flange 22d of the second body 22a in a liquid-tight manner using a flange seal or the like. The partition plate 12 has, for example, a first opening 12a where the piping 16 is arranged, First filter group 13 Several of the following First filter 13a and a fastening portion 12c to which a fastening member 18 is fastened.

[0024] The first opening 12a is formed so that the piping 16 can be connected thereto. The first opening 12a is formed, for example, in a cylindrical shape that protrudes upward when the partition plate 12 is attached to the filtration tank 11. The first opening 12a also has, for example, a female thread portion 12d formed on the inner circumferential surface as a means for fixing the piping 16.

[0025] For example, when the partition plate 12 is attached to the filtration tank 11, the second opening 12b is formed in the shape of a bottomed cylinder having a bottom 12f with an opening 12e formed in the center that protrudes downward. The number of second openings 12b is the same as the number of first filters 13a. The second openings 12b are arranged at equal intervals in the circumferential direction around the center of the partition plate 12. The inner diameter of the opening 12e formed in the bottom 12f of the second opening 12b is smaller than the outer diameter of the discharge portion 33 of the first filter 13a, but larger than the inner diameter of the discharge portion 33.

[0026] The fastening portion 12c is, for example, a screw hole in which a female screw is formed.

[0027] The first filter group 13 includes a plurality of first filters 13a. The plurality of first filters 13a are arranged in a row at equal intervals in the circumferential direction on the partition plate 12. The plurality of first filters 13a are arranged in a row with a gap between them at the center so that the piping 16 can be placed in the center. The first filter 13a is formed, for example, in a cylindrical shape with one end closed and the other end open. The first filter 13a includes an outer shell 31 having a plurality of holes 31a formed on the outside, a filtering member 32 provided within the outer shell 31 and covering the plurality of holes 31a, a cylindrical discharge portion 33 formed integrally with the outer shell 31 and having an outer diameter and an inner diameter smaller than those of the outer shell 31, and a ring-shaped gasket 34 such as an O-ring provided on the outer peripheral surface of the discharge portion 33.

[0028] The filtration member 32 filters the raw water that has passed through the multiple holes 31a provided in the outer shell 31 and passes the water to the discharge port 33. The filtration member 32 is, for example, a hollow fiber membrane filter and includes a prefilter and a hollow fiber membrane main body. The prefilter is provided inside the outer shell 31 and covers the multiple holes 31a. The hollow fiber membrane main body filters the raw water that has passed through the prefilter. The hollow fiber membrane main body is disposed inside the prefilter. Note that the filtration member 32 may be configured to include only the hollow fiber membrane main body without including a prefilter. Furthermore, although an example in which a hollow fiber membrane filter is used as the filtration member 32 has been shown, this is not limited thereto and a general-purpose filter may also be used. In other words, the filtration member 32 is not limited to a specific type or shape as long as it is capable of filtering raw water, and various filters can be used.

[0029] The outer shell 31 is formed with a diameter larger than the inner diameter of the second opening 12b. The outer shell 31 has a protrusion 31b at the end opposite the discharge portion 33, the protrusion 31b having a diameter smaller than the outer diameter of the outer shell 31. The discharge portion 33 is formed with a diameter slightly smaller than the inner diameter of the second opening 12b of the partition plate 12, and is inserted into the second opening 12b. One or more gaskets 34 are provided on the outer peripheral surface of the discharge portion 33. The gaskets 34 are in close contact with the outer peripheral surface of the discharge portion 33 and the inner peripheral surface of the second opening 12b, and provide a liquid-tight seal between the outer peripheral surface of the discharge portion 33 and the inner peripheral surface of the second opening 12b.

[0030] The connecting pipe 14 joins the flow paths of treated water discharged from the second filter group 17 and supplies the resultant water to the secondary side. The connecting pipe 14 fixedly supports the second filter group 17. The connecting pipe 14 also holds the upper ends of the plurality of first filters 13a held by the partition plate 12.

[0031] As a specific example, the connecting pipe 14 includes a cylindrical body 41, a top plate 42 formed at one end of the body 41, and a bottom plate 43 formed at the other end of the body 41. The top plate 42 is formed in a flat plate shape. The top plate 42 includes an eye plate 42a provided on the outer surface and third openings 42b for fixing the plurality of second filters 17a.

[0032] The eye plate 42a is formed so that the connecting pipe 14 and the various components fixed to the connecting pipe 14 can be suspended and lifted by a crane or the like.

[0033] The third openings 42b are formed, for example, in a cylindrical shape that protrudes upward from the top plate 42 in a position in which the connecting pipe 14 is disposed in the filtration tank 11. The number of third openings 42b is the same as the number of second filters 17a (described later) of the second filter group 17. The third openings 42b are arranged at equal intervals in the circumferential direction around the center of the partition plate 12. The inner diameter of the third openings 42b is formed to be slightly larger than the outer diameter of the discharge portion 53 of the second filter 17a so that the discharge portion 53 (described later) of the second filter 17a can be inserted therein, and a gasket 54 (described later) of the second filter 17a tightly contacts the third openings 42b to hold the second filters 17a.

[0034] The bottom plate 43 is formed in a disk shape and has a cylindrical pipe portion 43a extending downward in the center in a position where the connecting pipe 14 is disposed in the filtration tank 11. The bottom plate 43 also holds the first filters 13a together with the partition plate 12 by abutting against protrusions 31b formed on the outer bodies 31 of the first filters 13a. The pipe portion 43a is connected to the piping 16 and is a connecting portion that fluidly connects the connecting pipe 14 and the piping 16. The pipe portion 43a joins the treated water from the second filters 17a and guides it to the piping 16. The pipe portion 43a extends in a circular pipe shape in the vertical direction.

[0035] The plate 15 is fastened to the partition plate 12 via fastening members 18. The plate 15 is fixed to the partition plate 12 with the fastening members 18 in a state in which the first filter group 13, the connecting pipe 14, the piping 16, and the second filter group 17 can be arranged between the plate 15 and the partition plate 12. The plate 15 includes, for example, a fourth opening 15a formed in the center, a plurality of fifth openings 15b formed around the fourth opening 15a, and a plurality of sixth openings 15c provided on the outer periphery. For example, the plate 15 is formed in a polygonal or circular plate shape. In the example of this embodiment, the plate 15 is formed in a hexagonal plate shape with a chamfered top.

[0036] The fourth opening 15a is a hole for supplying raw water to the space on the inner surface side of the plate 15.

[0037] Fifth opening 15b is an opening that holds second filter 17a. For example, fifth opening 15b has an inner diameter that is the same as or slightly smaller than the outer diameter of protrusion 51b of outer shell 51 of second filter 17a, and by arranging protrusion 51b of outer shell 51, plate 15 holds the upper end of second filter 17a.

[0038] The sixth openings 15c are arranged, for example, at equal intervals in the circumferential direction of the plate 15. The sixth openings 15c are formed with an inner diameter that allows the fastening members 18 to be inserted therethrough.

[0039] The piping 16 extends in one direction. One end (upper end) of the piping 16 engages with the pipe portion 43a of the connecting pipe 14, and the other end (lower end) of the piping 16 engages with the first opening 12a of the partition plate 12. As a specific example, one end of the piping 16 has a diameter slightly smaller than the inner diameter of the pipe portion 43a so that it can be inserted into the pipe portion 43a, and has one or more O-rings as gaskets 16a on its outer circumferential surface. The length of the one end of the piping 16 inserted into the pipe portion 43a varies depending on the length of the second filter group 17 disposed between the partition plate 12 and the connecting pipe 14. The other end of the piping 16 has, on its outer circumferential surface, a male thread portion 16b that threadably engages with a female thread portion 12d formed in the first opening 12a of the partition plate 12, and a multi-sided flange 16c for rotating the piping 16. For example, the multi-sided flange 16c is a six-sided flange. The flow path resistance of such pipe 16 is greater than the flow path resistance of second chamber 11b. In another example, pipe portion 43a may be inserted into pipe 16 to fluidly connect connecting pipe 14 and pipe 16.

[0040] The second filter group 17 includes a plurality of second filters 17a. The plurality of second filters 17a are arranged in a circumferentially spaced relationship on the connecting pipe 14. Each second filter 17a is formed, for example, in a cylindrical shape with one end closed and the other end open. The second filter 17a includes an outer shell 51 having a plurality of holes 51a formed on its exterior, a filtering member 52 disposed within the outer shell 51 and covering the holes 51a, a cylindrical discharge portion 53 formed integrally with the outer shell 51 and having smaller outer and inner diameters than the outer shell 51, and a ring-shaped gasket 54, such as an O-ring, disposed on the outer peripheral surface of the discharge portion 53. For example, the second filter 17a may have the same configuration as the first filter 13a, but may have a different axial length from the first filter 13a.

[0041] The filtration member 52 filters the raw water that has passed through the multiple holes 51a provided in the outer shell 51 and passes the water to the discharge port 53. The filtration member 52 is, for example, a hollow fiber membrane filter and includes a prefilter and a hollow fiber membrane main body. The prefilter is provided inside the outer shell 51 and covers the multiple holes 51a. The hollow fiber membrane main body filters the raw water that has passed through the prefilter. The hollow fiber membrane main body is disposed inside the prefilter. Note that the filtration member 52 may be configured to include only the hollow fiber membrane main body without including a prefilter. Furthermore, although an example in which a hollow fiber membrane filter is used as the filtration member 52 has been shown, this is not limited thereto and a general-purpose filter may also be used. In other words, the filtration member 52 is not limited to a specific type or shape as long as it is capable of filtering raw water, and various filters can be used.

[0042] The outer shell 51 is formed with a diameter larger than the inner diameter of the third opening 42b of the connecting pipe 14. The outer shell 51 has a protrusion 51b at the end opposite the discharge portion 53, the protrusion 51b having a diameter smaller than the outer diameter of the outer shell 51. The discharge portion 53 is formed with a diameter slightly smaller than the inner diameter of the third opening 42b and is inserted into the third opening 42b. One or more gaskets 54 are provided on the outer peripheral surface of the discharge portion 53. The gaskets 54 are in close contact with the outer peripheral surface of the discharge portion 53 and the inner peripheral surface of the third opening 42b, and provide a liquid-tight seal between the outer peripheral surface of the discharge portion 53 and the inner peripheral surface of the third opening 42b.

[0043] A plurality of fastening members 18 are provided to secure the partition plate 12 and the plate 15 together. For example, the fastening members 18 include a double-headed screw bolt 18a and a nut 18b. Both of the double-headed screw bolts 18a have male threads formed on both ends. One end of each of the double-headed screw bolts 18a is threaded into a fastening portion 12c, which is a threaded hole in the partition plate 12. The other end of each of the double-headed screw bolts 18a is inserted into a sixth opening 15c of the plate 15, and a nut 18b is fastened to each of the double-headed screw bolts 18a.

[0044] In the clarification device 1 configured in this manner, the first filter group 13 and the piping 16 are fixed to the partition plate 12 fixed to the filtration tank 11, and the piping 16 and the second filter group 17 are liquid-tightly and fluidly connected to the connecting pipe 14. The second filter group 17 is also fixed to the connecting pipe 14. Then, with the protrusions 51b of the plurality of second filters 17a of the second filter group 17 arranged in the fifth openings 15b of the plate 15, the partition plate 12 and the plate 15 are fastened together by the fastening members 18 in a direction in which the partition plate 12 and the plate 15 approach each other. As a result, the partition plate 12 forms a first chamber 11a and a second chamber 11b in the filtration tank 11, and the first chamber 11a is continuous with the second chamber 11b via the first filter group 13 and the second filter group 17.

[0045] Next, the flow of water within the clarification device 1 will be described. The water flow is shown by arrows in Figure 3. First, when raw water to be clarified is supplied from the raw water inlet 21c, the raw water moves into the first chamber 11a and moves from the top to the bottom of the first chamber 11a. At this time, the raw water passes through each first filter 13a of the first filter group 13 and each second filter 17a of the second filter group 17. The raw water is filtered by passing through the first filter 13a and the second filter 17a.

[0046] The treated water filtered by first filter 13a moves from discharge portion 33 of first filter 13a to second chamber 11b. Then, the treated water filtered by each second filter 17a joins in connecting pipe 14 and moves to second chamber 11b via piping 16. Then, the treated water joined in second chamber 11b moves to the secondary side from treated water outlet 22c.

[0047] In the clarification device 1 configured in this manner, each first filter 13a of the first filter group 13 arranged in the lower part of the filtration tank 11 is mounted on the partition plate 12 and connected to the second chamber 11b, and each second filter 17a of the second filter group 17 arranged in the upper part of the filtration tank 11 is connected to the second chamber 11b via the connecting pipe 14 and the piping 16. Therefore, when treated water that has passed through the multiple second filters 17a moves to the second chamber 11b, it passes through the piping 16, which has a higher flow resistance than the second chamber 11b. In other words, the first filter group 13 and the second filter group 17 are arranged in a countercurrent direction to the flow of raw water in the filtration tank 11.

[0048] A larger amount of raw water is treated in the first filter group 13 than in the second filter group 17. Therefore, each first filter 13a of the first filter group 13 becomes clogged before each second filter 17a of the second filter group 17.

[0049] Therefore, even if each first filter 13a of the first filter group 13 becomes clogged, the second filter group 17 becomes clogged more slowly, so when it is time to replace the filters, it is possible to replace the first filter group 13 but not the second filter group 17.

[0050] That is, when the multiple filters 13a, 17a become increasingly clogged and the filtration loss increases, it is sufficient to replace the first filter 13a of the first filter group 13 in which clogging has progressed among the multiple filters 13a, 17a used in the clarification device 1. Therefore, after the filter replacement, the second filter 17a of the second filter group 17 that was being used can be reused. Also, rotary operation becomes possible in which the second filter 17a that is not very clogged is installed in the first filter group 13 at the time of filter replacement.

[0051] As described above, the clarification device 1 can reduce the number of filter replacements, thereby reducing running costs. Furthermore, the clarification device 1 having such a first filter group 13 and a second filter group 17 has a simple configuration in which the flow resistance of the pipe 16 through which treated water treated by the second filter group 17 flows is smaller than the flow resistance of the second chamber 11b, and when treated by the clarification device 1, the integrated flow rate of the first filter group 13 can be made larger than the integrated flow rate of the second filter group 17. Therefore, the clarification device 1 can prevent an increase in manufacturing costs. Furthermore, the clarification device 1 can perform treatment without providing accessories such as water quality measuring devices and control devices, thereby preventing an increase in costs including manufacturing costs, equipment costs, and running costs.

[0052] Furthermore, the partition plate 12 is fixed by being sandwiched between the flanges 21d, 22d of the raw water-side filtration tank 21 and the treated water-side filtration tank 22 of the filtration tank 11. Therefore, the partition plate 12 can be disassembled from the filtration tank 11. For example, when the filters 13a, 17a are removed, there is a risk that a small amount of raw water may flow into the second chamber 11b of the treated water-side filtration tank 22, etc. However, by making the partition plate 12 disassemblable, it becomes possible to clean the second chamber 11b (the partition plate 12 and the treated water-side filtration tank 22).

[0053] Furthermore, the piping 16 has a packing 16a on the outer periphery of the connection portion with the connecting pipe 14 and is configured to be inserted into the pipe portion 43a of the connecting pipe 14. Therefore, the insertion length of the piping 16 into the pipe portion 43a of the connecting pipe 14 can be changed. In other words, the clarification device 1 can change the distance from the partition plate 12 and the connecting pipe 14 to the bottom plate 43. Therefore, multiple types of first filters 13a with different axial lengths can be used in the first filter group 13. That is, by configuring the piping 16 in this way, it is possible to accommodate different lengths of the first filters 13a while connecting the partition plate 12 and the connecting pipe 14. Furthermore, when replacing the filters, the connecting pipe 14 can be easily removed from above the filtration tank 11, facilitating the replacement of the first filter group 13.

[0054] As described above, according to the clarification device 1 of one embodiment of the present invention, costs can be reduced by providing a first filter group 13 and a second filter group 17 and connecting the second filter group 17 to the second chamber 11b via piping 16 having a higher flow resistance than the second chamber 11b.

[0055] The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected elements from the disclosed elements. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention. The following is a description equivalent to the invention described in the original claims of the present application. [1] a filtration tank; A partition plate that separates the filtration tank into a first chamber on the raw water side and a second chamber on the treated water side; a first filter group including a plurality of first filters provided in the first chamber and having a secondary side connected to the second chamber; a second filter group provided in the first chamber and including a plurality of second filters; a connecting pipe that joins the outlets of the plurality of second filters; a pipe that connects the connecting pipe and the second chamber and has a flow resistance greater than a flow resistance of the second chamber; A clarification device comprising: [2] The second chamber is disposed lower in the filtration tank than the first chamber, The clarification device according to [1], wherein the second filter group is disposed above the first filter group and is held integrally with the first filter group. [3] A plate that holds the upper portions of the plurality of second filters; a fastening member that fixes the plate to the partition plate, the piping is fixed to the connecting pipe and the partition plate, and connects the connecting pipe to the second chamber; the first filter is fixed to the partition plate, The clarification device according to [2], wherein the second filter is fixed to the connecting pipe. [4] The filtration tank includes a raw water side filtration tank that forms the first chamber and a treated water side filtration tank that forms the second chamber, The clarification device according to any one of [1] to [3], wherein the partition plate is fixed to the filtration tank by being sandwiched between the raw water side filtration tank and the treated water side filtration tank. [5] The connecting pipe joins the treated water from the plurality of second filters and has a connecting portion extending in a tubular shape in the vertical direction, The pipe extends in one direction, and one end of the pipe is provided with a ring-shaped sealing member that tightly seals the pipe with the connecting portion, and the other end is fixed to the partition plate, [4] The clarification device according to [4], wherein one of the connection part and the piping is inserted into the other of the connection part and the piping. [Explanation of symbols]

[0056] 1...turbidity removal device, 11...filtration tank, 11a...first chamber, 11b...second chamber, 12...partition plate, 12a...first opening, 12b...second opening, 12c...fastening portion, 12d...female thread portion, 12e...opening, 12f...bottom, 13...first filter group, 13a...first filter, 14...connecting pipe, 15...plate, 15a...fourth opening, 15b...fifth opening, 15c...sixth opening, 16...piping, 16a...packing, 16b...male thread portion, 16c...multi-sided flange, 17...second filter Filter group, 17a...second filter, 18...fastening member, 18a...double-threaded bolt, 18b...nut, 21...raw water side filtration tank, 21a...first body, 21d...flange, 22...treated water side filtration tank, 22a...second body, 22d...flange, 31...outer body, 32...filtration member, 33...discharge portion, 34...gasket, 41...body, 42...top plate, 42b...third opening, 43...bottom plate, 43a...pipe portion, 51...outer body, 52...filtration member, 53...discharge portion, 54...gasket.

Claims

1. A filter tank, A partition plate that divides the filtration tank into a first chamber on the raw water side and a second chamber on the treated water side; a first filter group including a plurality of first filters provided in the first chamber and having secondary sides connected to the second chamber; a second filter group provided in the first chamber and including a plurality of second filters; a connecting pipe that joins the outlets of the plurality of second filters; a pipe connecting the connecting pipe and the second chamber; Equipped with the partition plate has a first opening for connecting the piping and a plurality of second openings for fixing the first filter; a discharge portion of the first filter inserted into the second opening; A clarification device, wherein one end of the piping is connected to the connecting pipe, and the other end of the piping is fixed to the first opening.

2. The second chamber is disposed lower in the filtration tank than the first chamber, The clarification device according to claim 1 , wherein the second filter group is disposed above the first filter group and is held integrally with the first filter group.

3. a plate for holding the upper portions of the plurality of second filters; a fastening member that fixes the plate to the partition plate, the piping is fixed to the connecting pipe and the partition plate, and connects the connecting pipe to the second chamber; the first filter is fixed to the partition plate, The clarification device according to claim 2 , wherein the second filter is fixed to the connecting pipe.

4. The filtration tank includes a raw water side filtration tank that forms the first chamber and a treated water side filtration tank that forms the second chamber, The clarification device according to claim 1 , wherein the partition plate is fixed to the filtration tank by being sandwiched between the raw water side filtration tank and the treated water side filtration tank.

5. the connecting pipe joins the treated water from the plurality of second filters and has a connecting portion extending in a tubular shape in the vertical direction, The pipe extends in one direction, and one end of the pipe is provided with a ring-shaped sealing member that tightly seals the pipe with the connecting portion, and the other end is fixed to the partition plate, The clarification device according to claim 4 , wherein one of the connection part and the piping is inserted into the other of the connection part and the piping.

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