Filtration device

Abstract

To provide a filtration device that can improve filtration performance and backwashing efficiency with a simple configuration. [Solution] The filtration device 1 comprises a cylindrical tank body 21 having an opening 21b at its upper end, a filter material 22 provided inside the tank body 21 for removing impurities contained in water, a pipe 24 provided in the tank body 21 with its lower end located on the bottom side of the tank body 21 and having an outer diameter smaller than the inner diameter of the opening 21b, a plate-shaped improvement plate 26 provided in the pipe 24, located below the opening 21b and above the filter material 22, having an outer diameter larger than the outer diameter of the pipe 24 and a flat main surface, an outer peripheral wall 27b provided at the lower end of the pipe 24 and forming the outermost outermost wall surface with multiple gaps, and a bottom surface portion 27c that is spaced apart from and facing the pipe 24 and forming the bottom surface.

Description

Technical Field

[0004] , , , , , , ,

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[0001] The present invention relates to a filtration device for removing impurities contained in water.

Background Art

[0002] Conventionally, a filtration device for removing impurities contained in water as water treatment has been known (see, for example, Patent Document 1). For example, in the filtration device, a filtration material such as an ion exchange resin is provided in a filtration tank to remove iron ions, manganese ions or nitrate nitrogen contained in water. When such a filtration device performs water treatment, iron ions and the like are adsorbed on the filtration material, and the filtration performance deteriorates. Therefore, the filtration device performs a backwashing operation in which water is periodically flowed in the reverse direction to loosen the filtration material and remove dust and the like from the raw water attached to the filtration material and discharge it to the outside, and a regeneration operation in which brine is passed through to exchange the iron ions and manganese ions adsorbed by the filtration material with sodium ions contained in salt to regenerate the filtration material.

[0003] In addition, as a technique for improving the backwashing efficiency of the backwashing operation, a technique for peeling off particulate substances and contaminants attached to the filtration material from the filtration material by generating friction of the granular filtration material by colliding the granular filtration material with a swirling flow imparting member is also considered (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, while the aforementioned swirling flow imparting member actively generates friction and collisions between the accumulated granular filter material at the top during backwashing operation to enhance the delamination effect, it had challenges in backwashing the entire filter material inside the filter tank, particularly the filter material at the bottom of the filter tank.

[0006] Therefore, the present invention aims to provide a filtration device that can improve the backwashing efficiency of filtering the entire filter material. [Means for solving the problem]

[0007] According to one aspect of the present invention, the filtration device comprises a cylindrical tank body having an opening at its upper end; a filter material provided inside the tank body for removing impurities contained in water; a pipe provided in the tank body, with its lower end located on the bottom side of the tank body, and having an outer diameter smaller than the inner diameter of the opening; a plate-shaped improvement plate provided in the pipe, located below the opening and above the filter material, having an outer diameter larger than the outer diameter of the pipe and a flat main surface; an outer peripheral wall provided at the lower end of the pipe, forming a plurality of spaced outermost wall surfaces; and a bottom surface portion that is spaced apart from and facing the pipe, forming a bottom surface. [Effects of the Invention]

[0008] According to the present invention, a filtration device that can improve backwashing efficiency can be provided. [Brief explanation of the drawing]

[0009] [Figure 1] A side view showing the configuration of a filtration device according to an embodiment of the present invention. [Figure 2] This diagram shows a partial cross-section of the filtration tank configuration of the filtration device, as well as a side view illustrating the water flow during normal operation and regeneration operation. [Figure 3] This diagram shows a partial cross-section of the filtration tank configuration of the filtration device, as well as a side view illustrating the water flow during backwashing. [Figure 4] A side view showing the main components of the piping used in the filtration tank. [Figure 5] A cross-sectional view showing another example of how to mount the same support plate. [Figure 6] A cross-sectional view showing another example of how to mount the same support plate. [Figure 7] Cross-sectional view showing another example of the same upper plate. [Modes for carrying out the invention]

[0010] Hereinafter, a filtration apparatus 1 according to an embodiment of the present invention will be described with reference to Figures 1 to 7. Figure 1 is a side view showing the configuration of a filtration device 1 according to an embodiment of the present invention, Figures 2 and 3 are side views showing a partial cross-section of the filtration tank 12 of the filtration device 1, Figure 2 shows the water flow F1 during normal operation and regeneration operation, and Figure 3 shows the water flow F2 during reverse operation. Figure 4 is a side view showing the configuration of the strainer 27 of the piping 24 used in the filtration tank 12, Figure 5 is a cross-sectional view showing another example of how to attach the riser plate 26, different from the example in Figure 2, and Figure 6 is a cross-sectional view showing another example of how to attach the riser plate 26, different from the examples in Figure 2 and Figure 5. Figure 7 is a cross-sectional view showing another example of the riser plate 26.

[0011] As shown in Figure 1, the filtration device 1 comprises a base 11, a filtration tank 12, a brine tank 13, and a control panel 14. The filtration device 1 removes impurities contained in water. Specifically, the filtration device 1 is a so-called ion-exchange type iron and manganese removal tank, using ion exchange resin as the filter material 22 provided in the filtration tank 12. The filtration device 1 may also be equipped with an injection device for injecting chemicals such as sodium hypochlorite on the downstream side. The base 11 supports the filtration tank 12, the brine tank 13, and the control panel 14.

[0012] As shown in Figure 2, the filtration tank 12 comprises a tank body 21, a filter material 22 provided inside the tank body 21, a control valve 23 provided at the top of the tank body 21, piping 24 connected to the control valve 23, a filter 25 provided inside the tank body 21 and between the control valve 23, an improvement plate 26 fixed to the outer surface of the piping 24, and a strainer 27 fixed to the lower end of the piping 24.

[0013] The tank body 21 houses an ion exchange resin inside. For example, the tank body 21 is made of FRP (Fiber Reinforced Plastics). The tank body 21 comprises, for example, a bottomed cylindrical body portion 21a and an opening portion 21b formed at the upper end of the body portion 21a. The body portion 21a is, for example, formed with a dome shape at the bottom and top, and an intermediate portion between the bottom and top formed as a cylinder with a certain inner diameter. The body portion 21a may be formed integrally with the bottom, intermediate portion and top, or the bottom, intermediate portion and top may be formed separately and then integrally formed by fastening fasteners or bonding.

[0014] The mouth portion 21b is located in the center of the top of the body portion 21a. For example, the mouth portion 21b is formed in a cylindrical shape that extends vertically from the top of the body portion 21a. The inner diameter of the mouth portion 21b is formed to be smaller than the inner diameter of the body portion 21a.

[0015] The filter material 22 is made of ion exchange resin and is provided up to a predetermined height in the body 21a. The filter material 22 is provided up to the center in the height direction of the body 21a and is not provided in the upper part of the body 21a. In other words, the filter material 22 is positioned lower than the top and forms a space in the upper part of the body 21a where the filter material 22 is not provided. The filter material 22 may use a single ion exchange resin or multiple ion exchange resins. As a specific example, the filter material 22 is formed by using two types of ion exchange resin, with the lower layer being a cation exchange resin and the upper layer being an anion exchange resin.

[0016] The control valve 23 has a plurality of flow paths and a switching valve for switching the connection of the plurality of flow paths. The control valve 23 may, for example, have a control unit for controlling the switching of the switching valve, or may be configured to control the switching of the switching valve by the control panel 14. The control valve 23 switches the flow of water and brine by switching the switching valve. For example, the control valve 23 is fixed to the mouth portion 21b and the pipe 24 is connected thereto. The control valve 23 is on the primary side of the filtration device 1, a water supply source that is a water source for performing water treatment, on the secondary side of the filtration device 1, a water supply destination such as a filtration tank that supplies treated water that has undergone water treatment, the brine tank 13, the pipe 24, inside the body portion 21a via the mouth portion 21b, and is connected to a drain (drain destination), and selectively connects the water supply source, the water supply destination, the brine tank 13, the pipe 24, and the mouth portion 21b (inside the body portion 21a).

[0017] The control valve 23 is connected to a water supply pipe connected to a well. By opening and closing, the control valve 23 performs a normal operation of adsorbing and filtering iron ions, manganese ions, or nitrate nitrogen contained in the water supplied from the water supply source, a backwash operation for washing the filter medium 22 in the tank body 21, and a regeneration operation of passing brine through the ion exchange resin to exchange iron ions, manganese ions, etc. adhering to the filter medium 22 with sodium ions and discharging them to the outside, and switches between them. Note that the control valve 23 may be further formed so as to be switchable to an extrusion operation for discharging brine during the regeneration operation, a washing operation for injecting raw water and washing, a water injection operation for injecting water into the brine tank 13, etc.

[0018] As a specific example, in normal operation, the control valve 23 switches the switching valve so that water sequentially passes through the water supply source, the inside of the body portion 21a, the pipe 24, and the water supply destination. Also, in backwash operation, the control valve 23 switches the switching valve so that water sequentially passes through the water supply destination, the pipe 24, the inside of the body portion 21a, and the drain. Further, in regeneration operation, the control valve 23 switches the switching valve so that brine sequentially passes through the brine tank, the inside of the body portion 21a, the pipe 24, and the drain. Also, in cleaning operation, the control valve 23 switches the switching valve so that water sequentially passes through the water supply source or the water supply destination, the inside of the body portion 21a, the pipe 24, and the drain. Further, as filling operation, the control valve 23 switches the switching valve so that treated water sequentially passes through the water supply destination and the brine tank.

[0019] The pipe 24 is connected to the control valve 23. The outer diameter of the pipe 24 is formed to be smaller than the inner diameter of the mouth portion 21b. Thereby, a flow path connecting the control valve 23 and the body portion 21a is formed between the outer peripheral surface of the pipe 24 and the inner peripheral surface of the mouth portion 21b. The pipe 24 is a collecting pipe that allows the water that has passed through the filter medium 22 to flow to the secondary side during normal operation of treating water. As shown in FIGS. 2 and 3, the pipe 24 is a cylindrical pipe formed of a resin material, and the lower end is disposed on the bottom side of the body portion 21a. As shown in FIG. 4, a strainer 27 is attached to the lower end of the pipe 24.

[0020] The filter 25 is assembled to the device having the control valve 23, is disposed at the mouth portion 21b, and is formed so as to allow the pipe 24 to be inserted therethrough. That is, the filter 25 is provided in the flow path between the inner peripheral surface of the mouth portion 21b and the outer peripheral surface of the pipe 24, and suppresses the passage of substances other than the water in the flow path between the inner peripheral surface of the mouth portion 21b and the outer peripheral surface of the pipe 24. For example, the filter 25 prevents the passage of solid impurities contained in water and the filter medium 22, and allows water to pass through. The filter 25 prevents the movement of the filter medium 22 to the mouth portion 21b during backwash operation.

[0021] The filter 25 comprises a first annular end 25a that is attached to a device having a control valve 23 and is close to the opening end on the body portion 21a side of the mouth portion 21b; a second annular end 25b that is located below and in the opposite direction from the first end 25a, into which the pipe 24 is inserted; and a filter body 25c that connects the first end 25a and the second end 25b and is an outer ring shape around the axis of the filter 25. The diameter of the second end 25b is smaller than the diameter of the first end 25a. The filter body 25c is conical in shape, with its diameter decreasing downwards. The filter body 25c has multiple slit shapes along the axial direction of the pipe 24. That is, the filter body 25c has multiple slits that extend in the direction along the extension direction of the filter body 25c (up and down direction), and these slits allow water to pass through, while preventing solid impurities and filter material 22 contained in the water from passing through. In Figure 5, the portion of the filter 25 that faces the piping 24 in the radial direction is omitted, and the piping 24 and the riser plate 26 are shown in cross-section.

[0022] The riser plate 26 is formed in the shape of a disc with an opening in the center that allows it to be attached to the pipe 24. That is, as shown in Figure 4, the riser plate 26 is formed in the shape of an annular plate, into which the pipe 24 is inserted and fixed in a predetermined position on the pipe 24, and protrudes in an annular shape from the outer surface of the pipe 24. The riser plate 26 is formed with both main surfaces in the axial direction of the pipe 24 being flat. The riser plate 26 is provided on the pipe 24 and is positioned below the opening 21b and the filter 25, and above the filter material 22.

[0023] The inner diameter of the riser plate 26 is formed to be the same as or slightly smaller than the outer diameter of the pipe 24. The outer diameter of the riser plate 26 is larger than the outer diameter of the pipe 24 and smaller than or equal to the inner diameter of the opening 21b. For example, the riser plate 26 is formed to be the same as or slightly smaller than the inner diameter of the opening 21b so that it can be inserted into and removed from the opening 21b. For example, when the inner diameter of the opening 21b is Φ70mm, the outer diameter of the riser plate 26 is Φ69mm. Also, as an example, the thickness of the riser plate 26 is 5mm. Furthermore, the outer diameter of the filter body 25c is smaller than the outer diameter of the riser plate 26.

[0024] The riser plate 26 is positioned below the opening 21b, thereby diffusing the water flowing into the body 21a from the opening 21b radially outward, and also diffusing the water that has moved from the piping 24 through the strainer 27 to the body 21a as it moves to the opening 21b radially outward. For example, as shown in Figure 2, the riser plate 26 is fixed to the piping 24 with a sealing member 26a such as an O-ring. Specifically, the riser plate 26 may have a sealing groove formed on its inner circumference where the sealing member 26a is placed, and the sealing member 26a is provided in the sealing groove and fixed to the piping 24 by the compressed sealing member 26a. Furthermore, as an alternative method for attaching the improvement plate 26 to the piping 24, as shown in Figure 5, the improvement plate 26 may be fixed to the piping 24 together with the sealing member 26a, or in place of the sealing member 26a, by a fixing device 26b such as a C-ring. Alternatively, as shown in Figure 6, a cylindrical boss 26c may be provided, and the improvement plate 26 may be fixed to the piping 24 by a pin 26d that is radially fitted at the boss 26c. In addition, as shown in Figure 7, the improvement plate 26 may be integrated with the filter 25 by bonding, welding, or integral molding to the second end 25b of the filter 25.

[0025] As shown in Figure 4, the strainer 27 has multiple slits 27d, for example, in a direction perpendicular to the axial direction of the pipe 24, specifically in the circumferential direction, which prevents solid impurities and filter material 22 contained in the water from passing through, while allowing water to pass through. That is, the width of the slits 27d in the direction perpendicular to the circumferential direction is smaller than the width of the granular filter material 22.

[0026] As a specific example, the strainer 27 is formed by stacking an annular plate-shaped upper portion 27a, a plurality of annular plate-shaped stacked portions 27b, and a conical bottom portion 27c along the axial direction of the pipe 24 and fixing them with a fixing member. The outer circumferential surface of the strainer 27 is formed by the outer circumferential surfaces of the plurality of stacked portions 27b. The slit 27d is formed by minute gaps that occur between the upper portion 27a, the plurality of stacked portions 27b, and the bottom portion 27c, which are stacked in the axial direction. The strainer 27 is provided at the lower end of the pipe 24 and has a plurality of gaps, which are slits 27d. The plurality of stacked portions 27b form the outer circumferential wall, and the bottom portion 27c faces the pipe 24 at a distance and forms the bottom surface.

[0027] An opening approximately the same diameter as the pipe 24 is formed in the upper surface portion 27a, and the strainer 27 is assembled to the pipe 24 by inserting the lower end of the pipe 24 into the opening in the upper surface portion 27a. The outer diameter of the upper surface portion 27a, the outer diameter of the multiple stacked portions 27b, and the outer diameter of the bottom surface portion 27c are formed to be smaller than the inner diameter of the opening portion 21b. That is, the outer diameter of the strainer 27 is formed to be smaller than the inner diameter of the opening portion 21b and larger than the outer diameter of the pipe 24. In addition, the outer surface of the upper surface portion 27a and the outer surface of the bottom surface portion 27c, which is cone-shaped and facing downwards, are walls that do not allow water to pass through.

[0028] The control panel 14 controls the pump that supplies water from the water source to the secondary side, for example, based on the flow rate detected by the flow rate detector. The control panel 14 also controls the control valve 23 based on the operating time and the amount of water flowing through the filtration tank 12, switching between operation controls such as normal operation, backwash operation, regeneration operation, extrusion operation, and washing operation. The control panel 14 is also configured to output operating information, abnormal information, etc. to the outside through sound, light, display on a screen, communication to an external terminal, etc.

[0029] With the filtration device 1 configured in this way, when raw water during normal operation, brine during regeneration operation, or raw water or treated water during the washing operation after regeneration operation is injected into the body 21a from the opening 21b, the water flow becomes a flow from the top to the bottom of the body 21a, as shown by the solid arrow F1 in Figure 2. At this time, since the riser plate 26 is attached around the upper part of the piping 24 inside the tank body 21, the riser plate 26 is located directly below the opening between the inner surface of the opening 21b and the outer surface of the piping 24, which serves as the inlet for raw water and brine. Therefore, after the raw water and brine are supplied into the body 21a, they hit the riser plate 26, and the water flow is diffused. As a result, the water is diffused over a wide area on the outward side from the axial center of the body 21a (towards the inner wall surface of the body 21a). Therefore, the filter material 22 is evenly exposed to raw water or regenerated brine, which improves the filtration performance of the raw water, the regeneration and recovery rate of the filter material 22 by the brine, and the discharge efficiency of brine during the extrusion and washing operations after the regeneration operation.

[0030] As an evaluation test of the filtration performance of filtration device 1, water was passed through filtration device 1 equipped with the improvement plate 26 in the example and filtration device without the improvement plate 26 in the comparative example, with a cation exchange resin as the filter material 22 installed in the 25L tank body 21, and the amount of cation removal was evaluated. Raw water containing Mn=20ppm was passed through at a flow rate of 40L / min. The water flow was stopped when the treatment capacity decreased and the treated water concentration after passing through the filter material became Mn=0.05ppm or higher. As a result of the evaluation test, the amount of cation removal increased by about 15% when comparing filtration device 1 equipped with the improvement plate 26 in the example with filtration device without the improvement plate 26 in the comparative example. From these results, it is clear that the filtration performance of filtration device 1 is improved by providing the improvement plate 26. Thus, in the normal operation of filtration device 1, the amount of cation removal is increased by providing the improvement plate 26 compared to the configuration without the improvement plate 26.

[0031] As an evaluation test of the regeneration recovery rate of filtration device 1, a mixed-bed filtration tank was used in which an anion exchange resin was placed in the upper section and a cation exchange resin in the lower section as the filter material 22 within the tank body 21. Normal operation and regeneration operation were repeated, and the amount of cations removed was measured in each operation to determine the regeneration recovery rate. The method for calculating the regeneration recovery rate was as follows: Regeneration rate (%) = Amount of cations removed in the nth time / Amount of cations removed in the n-1 time That's what I decided.

[0032] Test results for the filtration device 1 equipped with the improvement plate 26 showed a regeneration recovery rate in the range of 76% to 93%. In contrast, the regeneration recovery rate for the filtration device without the improvement plate 26, which had been used previously and whose regeneration recovery rate had already been determined in field tests, was 63% to 73%. Therefore, it was clear that the regeneration recovery rate can be improved by providing the improvement plate 26.

[0033] Furthermore, in the filtration device 1, during backwash operation, the backwash water that flows into the strainer 27 after passing through the inside of the piping 24 collides with the bottom surface 27c of the strainer 27, passes through multiple circumferentially formed slits 27d and is discharged outward in the radial direction, passes through the filter material 22 in the body 21a, passes through the filter 25 and is discharged to the drain from the flow path between the outer circumference of the piping 24 and the opening 21b. That is, during backwash operation, the water flow is from below the body 21a upward, as shown by the dashed arrow F2 in Figure 3. At this time, as the water is discharged from the multiple circumferentially formed slits 27d in a direction perpendicular to the axial direction, it is discharged away from the axial center of the piping 24, and passes on the outer circumference side (inner circumferential surface side of the body 21a) of the filter material 22 from the central axis of the body 21a below the body 21a near the strainer 27.

[0034] Furthermore, since the pipe 24 is equipped with an upward plate 26, the backwash water that moves from the strainer 27 into the body 21a flows outside the upward plate 26 and moves to the opening 21b, passing over a wide area from the center to the outer side (inner circumferential surface) above the body 21a of the filter material 22. As a result, as shown in Figure 3, the backwash water flowing out from the multiple slits 27d of the strainer 27 of the pipe 24 does not flow along the pipe 24 but diffuses and flows throughout the entire filtration tank 12. As a result, the filter material 22 is loosened evenly by the backwash water. In particular, the filter material 22 is diffused and loosened below the body 21a around the strainer 27 where the granular filter material 22 accumulates. As a result, the granular filter material 22 that was previously stuck to the filter material separates, making it easier for debris and other particles attached to the filter material to detach from the filter material, and allowing minute turbidity components and debris to pass through the slits of the filter 25 and be discharged to the outside.

[0035] Furthermore, as the filter material 22 returns from solidified clumps to fine granular filter material 22, the surface area of ​​the exposed filter material 22 is restored, thereby improving the efficiency of adsorption of iron ions, manganese ions, and nitrate nitrogen during filtration operation, or removal of iron ions, etc., by saltwater during regeneration operation. In this way, the filtration device 1, with its strainer 27 and uplift plate 26 that discharge backwash water radially outward, prevents uneven distribution of the mixed parts of the filter material 22 during backwashing, loosens the entire filter material 22, and improves backwashing efficiency.

[0036] Furthermore, by making the improvement plate 26 a smooth, annular plate, it can be manufactured inexpensively and can be attached simply to the conventionally used piping (water collection pipe) 24, thereby suppressing an increase in manufacturing costs. In addition, by welding or integrally molding the improvement plate 26 to the second end of the filter 25, the piping 24 can be passed through the filter 25 having the improvement plate 26 and assembled to the opening 21b, so that even if multiple filtration devices 1 are manufactured, the improvement plate 26 can be provided in the same specific position.

[0037] Furthermore, if the tank body 21 is formed from FRP, which is used as the material for filtration tanks in many water treatment devices, it is generally necessary to make the opening 21b of the tank body 21 smaller. However, by making the outer diameter of the riser plate 26 less than or equal to the inner diameter of the opening 21b, it can be installed inside the tank body 21 without requiring additional processes such as cutting and re-bonding the tank body 21. Therefore, the filtration device 1 does not need to employ a costly manufacturing method. In addition, the piping 24 can be withdrawn from the opening 21b with the riser plate 26 installed during maintenance, and can be inserted from the opening 21b after maintenance. Thus, the filtration device 1 has high maintainability.

[0038] Furthermore, since the main surface of the riser plate 26 is flat and is smaller than or equal to the inner diameter of the opening 21b, it is smaller than the inner diameter of the body 21a, which suppresses an increase in resistance to water flow, i.e., an increase in filtration resistance and backwashing resistance. In addition, since the increase in resistance caused by the riser plate 26 can be suppressed, pressure loss in the filtration tank 12 can be suppressed.

[0039] Furthermore, while the piping 24 is held in place by fitting into the control valve 23, when inserted into the tank body 21 where the filter material 22 is provided, the piping 24 may be positioned at an angle to the axis of the body 21a. However, since the water collides with the riser plate 26 when it flows, the position of the piping 24 can also be aligned with the axis of the body 21a.

[0040] As described above, according to the filtration device 1 of the embodiment of the present invention, the filtration performance and backwashing efficiency can be improved with a simple configuration in which an improvement plate 26 having a flat main surface is provided on the piping 24.

[0041] Furthermore, in the above embodiment, the lower end of the pipe 24 is structured to allow water to flow in and out in the radial direction from a slit 27d along the circumferential direction of the strainer 27, but the embodiment is not limited to the above. For example, by providing spaced-apart opposing wall surfaces at the opening at the lower end of the pipe 24, water may be discharged from the pipe 24 radially during backwashing and water may flow in during filtration and regeneration. In addition, the slit 27d allows water to pass through while preventing the passage of solid impurities and filter material 22, but a mesh or filter may be used to prevent the passage of solid impurities and the like.

[0042] It should be noted that the present invention is not limited to the embodiments described above, and can be modified in various ways during implementation without departing from its essence. Furthermore, each embodiment may be combined as appropriate, and in that case, the combined effects can be obtained. Moreover, the above embodiments include various inventions, and various inventions can be extracted by selecting combinations from the multiple constituent elements disclosed. For example, if the problem can be solved and effects obtained even if some constituent elements are deleted from all the constituent elements shown in the embodiment, then the configuration with these deleted constituent elements can be extracted as an invention. [Explanation of Symbols]

[0043] 1...Filtration device, 11...Base, 12...Filtration tank, 13...Saltwater tank, 14...Control panel, 21...Tank body, 21a...Body section, 21b...Mouth section, 22...Filter material, 23...Control valve, 24...Piping, 25...Filter, 26...Uplift plate, 26a...Sealing member, 26b...Fixing device, 26c...Boss, 26d...Pin, 27...Strainer, 27a...Top section, 27b...Laminated section (outer wall), 27c...Bottom section, 27d...Slit.

Claims

1. A cylindrical tank body having an opening at the upper end, A filter material for removing impurities contained in water is provided inside the tank body, A pipe provided in the tank body, with its lower end located on the bottom side of the tank body, and having an outer diameter smaller than the inner diameter of the opening, A flat, plate-shaped improvement plate is provided in the piping, positioned below the opening and above the filter material, with an outer diameter larger than the outer diameter of the piping, and having a flat main surface. A strainer provided at the lower end of the aforementioned piping, having an outer peripheral wall that forms the outermost wall surface with multiple gaps, and a bottom surface that is spaced apart from and opposite to the aforementioned piping, forming a bottom surface, A filtration device equipped with the following features.

2. The filtration apparatus according to claim 1, wherein the outer diameter of the improvement plate is less than or equal to the inner diameter of the opening.

3. The filtration apparatus according to claim 1 or claim 2, wherein the improvement plate is integrally formed with the filter to which the opening is attached.

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