Strainer and filtration device

Abstract

To provide a strainer which enables back washing water to flow sufficiently to improve washing efficiency of a filter medium, and to provide a filter device including the strainer.SOLUTION: A strainer 9 is disposed on a filter bed 3 of a filter tank 2 in a filter device 1. The strainer 9 includes: a leg part 11 penetrating in a vertical direction; and a head part 12 which is formed having a diameter larger than that of the leg part 11 in a horizontal direction and provided at an upper end of the leg part 11. The head part 12 has a plurality of openings 13 which are open downward at the outer side relative to the leg part 11 in the horizontal direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a strainer that collects filtered water filtered in a filtration tank and allows the filtered water to flow out into the filtration tank for backwashing, and a filtration device including the strainer.

Background Art

[0002] Conventionally, a filtration device lays filter media on a filter bed of a filtration tank, filters raw water supplied to the filtration tank with the filter media, and arranges a plurality of strainers on the filter bed to collect the filtered water through the strainers. On the other hand, in order to wash (backwash) the filter media, the filtration device allows backwash water such as filtered water to flow into the filtration tank through the strainers.

[0003] For example, the filtration device disclosed in Patent Document 1 includes a filter body in which granular filter media is filled on a filter media outflow prevention filter, raw water is supplied from above, and filtered water is recovered from below the filter, a raw water supply pump for supplying raw water to the filter body, and a backwash water supply pump for switching from the supply of raw water to supply backwash water from below the filter and sending it above the filter. As the filter media outflow prevention filter, a nozzle type filter in which nozzles (strainers) with slits or pores are arranged upward on a flat plate is used.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In conventional technology, strainers are formed with openings facing upwards or to the sides, so when cleaning the filter media, backwash water flows into the filtration tank upwards or to the sides. In this case, the backwash water does not circulate sufficiently within the filtration tank, resulting in areas where the filter media does not flow properly and is not adequately cleaned.

[0006] The present invention aims to provide a strainer that can sufficiently circulate backwash water to improve the cleaning efficiency of the filter media, and a filtration device equipped with said strainer. [Means for solving the problem]

[0007] To solve the above problems, the strainer of the present invention is a strainer arranged in the filter bed of a filtration tank, comprising: legs that penetrate in the vertical direction; and a head that is formed to have a larger diameter than the legs in the horizontal direction and is provided at the upper end of the legs, wherein the head has a plurality of openings that are located outside the legs in the horizontal direction and open downward.

[0008] Furthermore, in order to solve the above problems, the filtration apparatus of the present invention comprises the above-mentioned plurality of strainers and the filtration tank, wherein the plurality of strainers are arranged in a staggered pattern on the filter bed of the filtration tank. [Effects of the Invention]

[0009] The present invention provides a strainer that can sufficiently circulate backwash water to improve the cleaning efficiency of the filter media, and a filtration device equipped with the strainer. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic cross-sectional view showing a filtration device according to an embodiment of the present invention. [Figure 2] This is a top view showing an example of the arrangement of strainers in the filter bed of a filtration device according to an embodiment of the present invention. [Figure 3]This is a cross-sectional view showing the filter bed and strainer in a filtration device according to an embodiment of the present invention. [Figure 4] This is a cross-sectional perspective view showing a strainer in a filtration device according to an embodiment of the present invention. [Modes for carrying out the invention]

[0011] A filtration device 1 according to an embodiment of the present invention will be described with reference to the drawings. As shown in Figure 1, the filtration device 1 comprises a filtration tank 2, a filter bed 3, a filter material 4, a raw water supply pipe 5, a filtered water recovery pipe 6, a backwash water supply pipe 7, a backwash water discharge pipe 8, and a plurality of strainers 9.

[0012] The filtration tank 2 has a vertical cylindrical shape, and the filtration chamber inside the filtration tank 2 is divided vertically by the filter bed 3 into an upper filtration chamber 2a and a lower filtration chamber 2b.

[0013] The filter bed 3 is formed in a plate shape that conforms to the inner circumference of the filtration tank 2 and is positioned inside the filtration tank 2 so as to partition the filtration chamber inside the filtration tank 2 in the vertical direction. As shown in Figure 2, the filter bed 3 has multiple through holes 3a for positioning multiple strainers 9, and the multiple through holes 3a are arranged in a staggered, close-packed layout such that the figure formed by connecting the positions of three adjacent through holes 3a with straight lines forms an equilateral triangle.

[0014] Furthermore, as shown in Figure 3, the filter bed 3 is preferably formed with a raised bottom at the center of the space between adjacent through-holes 3a, rather than at the location of the through-holes 3a. For example, it is preferable that the bottom be raised near the center of the equilateral triangle formed by connecting the locations of three adjacent through-holes 3a with straight lines. In other words, the filter bed 3 is formed with a raised bottom at the center of the space between adjacent strainers 9, rather than at the location of the strainers 9. The raised height of the filter bed 3 may be equal to the height of the strainers 9, or it may be higher than the height of the strainers 9.

[0015] The filter media 4 is made up of granular natural stone or the like, and is laid on the filter bed 3 in layers to a predetermined height.

[0016] The raw water supply pipe 5 is a pipe for supplying raw water to be filtered to the upper filtration chamber 2a, and is installed above the filtration tank 2, communicating with the upper filtration chamber 2a. The raw water supply pipe 5 is equipped with a raw water supply pump 5a for sending raw water from outside the filtration tank 2 to the upper filtration chamber 2a via the raw water supply pipe 5, and a raw water on / off valve 5b for switching the supply and stop of raw water.

[0017] The filtered water recovery pipe 6 is a pipe for recovering filtered water from the lower filtration chamber 2b to a water storage area (not shown) outside the filtration tank 2, and is installed in communication with the lower filtration chamber 2b at the bottom of the filtration tank 2. The filtered water recovery pipe 6 is equipped with a filtered water on / off valve 6b for switching between recovering and stopping filtered water.

[0018] The backwash water supply pipe 7 is a pipe for supplying backwash water to the lower filtration chamber 2b from a reservoir (not shown) outside the filtration tank 2 when the filter media 4 is washed (backwashed) in the filtration tank 2. It is installed at the bottom of the filtration tank 2 and communicates with the lower filtration chamber 2b. The backwash water supply pipe 7 is equipped with a backwash water supply pump 7a for supplying backwash water from outside the filtration tank 2 to the lower filtration chamber 2b via the backwash water supply pipe 7, and a backwash water on / off valve 7b for switching the supply and stop of backwash water.

[0019] The backwash water discharge pipe 8 is a pipe for discharging the backwash water (drainage) obtained by washing (backwashing) the filter media 4 in the filtration tank 2 from the upper filtration chamber 2a to the outside of the filtration tank 2, and is installed in communication with the upper filtration chamber 2a at the top of the filtration tank 2. The backwash water discharge pipe 8 is equipped with a drain on / off valve 8a for switching the discharge of backwash water (drainage) on and off.

[0020] The plurality of strainers 9 are for introducing filtered water from the upper filtration chamber 2a to the lower filtration chamber 2b during the filtration of raw water, and discharging backwash water from the lower filtration chamber 2b to the upper filtration chamber 2a during the backwashing of the filter medium 4. The plurality of strainers 9 are respectively attached to a plurality of through-holes 3a formed in the filter bed 3, and communicate the upper filtration chamber 2a and the lower filtration chamber 2b. Each strainer 9 may be detachable from the through-hole 3a of the filter bed 3. The plurality of strainers 9 are arranged in a staggered pattern such that the figure formed by connecting the positions of three adjacent strainers 9 in a straight line forms an equilateral triangle by being arranged with respect to the plurality of through-holes 3a.

[0021] As shown in FIG. 4, each strainer 9 includes a leg portion 11 penetrating in the vertical direction, and a hollow head portion 12 formed to have a larger diameter than the leg portion 11 in the horizontal direction and provided at the upper end of the leg portion 11. The leg portion 11 communicates with the hollow portion of the head portion 12. Each strainer 9 is attached to the filter bed 3 by inserting and fixing the leg portion 11 into the through-hole 3a of the filter bed 3.

[0022] The head portion 12 has a plurality of openings 13 that open downward and outward of the leg portion 11 in the horizontal direction. The head portion 12 has a substantially disk-shaped outer shape and has a circular bottom portion 14 that is grounded to the filter bed 3 around the through-hole 3a of the filter bed 3 when attached to the filter bed 3. The head portion 12 also has a lower inclined surface 15 that slopes upward and outward of the bottom portion 14 in the horizontal direction. The lower inclined surface 15 is preferably formed to slope at an acute angle (45 degrees or less) with respect to the horizontal direction.

[0023] The plurality of openings 13 are formed in the lower inclined surface 15 of the head portion 12 and are formed, for example, by a plurality of slits that extend radially when viewed from the central side of the head portion 12 in the horizontal direction. The slits constituting the openings 13 are inclined at an acute angle downward with respect to the horizontal direction. Each opening 13 is formed to have an opening dimension smaller than the particle size of the filter medium 4.

[0024] Furthermore, the head 12 has a curved upper surface 16 such that the outer side is lower than the central side in the horizontal direction, and for example, the upper surface 16 has a shape that bulges upward towards the center, such as a dome shape or a cone shape.

[0025] Next, the filtration operation of filtration device 1 will be explained.

[0026] First, by operating the raw water supply pump 5a and opening the raw water shut-off valve 5b, raw water is supplied from outside the filtration tank 2 to the upper filtration chamber 2a of the filtration tank 2 via the raw water supply pipe 5. The raw water supplied to the upper filtration chamber 2a is filtered by the filter media 4 on the filter bed 3, and the filtered water is introduced into multiple strainers 9 through multiple openings 13, and further supplied to the lower filtration chamber 2b via each of the strainers 9. In addition, by opening the filtered water shut-off valve 6b, the filtered water is recovered from the lower filtration chamber 2b to a water storage area (not shown) outside the filtration tank 2 via the filtered water recovery pipe 6.

[0027] Next, we will explain the backwashing operation of the filtration device 1.

[0028] First, the backwash water supply pump 7a is activated and the backwash water shut-off valve 7b is opened, supplying backwash water from an external water reservoir (not shown) outside the filtration tank 2 to the lower filtration chamber 2b of the filtration tank 2 via the raw water supply pipe 5. The backwash water supplied to the lower filtration chamber 2b is introduced from the leg section 11 into a plurality of strainers 9 and ejected into the upper filtration chamber 2a of the filtration tank 2 through a plurality of openings 13 in each strainer 9.

[0029] At this time, since each opening 13 is inclined at a sharp angle downward with respect to the horizontal direction, the backwash water is ejected diagonally downward by each opening 13. Compared to backwash water ejected diagonally downward in this way, backwash water ejected diagonally downward results in a more uniform flow distribution throughout the stacked filter media 4, and no areas with significantly low flow are created. In addition, by opening the drain valve 8a, the backwash water (wastewater) used to wash (backwash) the filter media 4 is discharged from the upper filtration chamber 2a to the outside of the filtration tank 2 via the backwash water discharge pipe 8.

[0030] In the above-described embodiment, an example was explained in which the filtration device 1 is provided with a raw water supply pipe 5 and a backwash water discharge pipe 8 separately in the upper part (upper filtration chamber 2a) of the filtration tank 2. However, the present invention is not limited to this example. For example, the filtration device 1 may be configured with a single common pipe for the raw water supply pipe 5 and the backwash water discharge pipe 8, and this common pipe may be branched outside the filtration tank 2 to the raw water supply side and the backwash water discharge side.

[0031] In the embodiment described above, an example was explained in which the filtration device 1 is equipped with a filtered water recovery pipe 6 and a backwash water supply pipe 7 separately in the lower part of the filtration tank 2 (lower filtration chamber 2b). However, the present invention is not limited to this example. For example, the filtration device 1 may be configured with a single common pipe for the filtered water recovery pipe 6 and the backwash water supply pipe 7. This common pipe may be configured to branch outside the filtration tank 2 to the filtered water recovery side and the backwash water supply side, or it may be connected to a water storage area (not shown) outside the filtration tank 2 without branching, and the filtration device 1 may use the filtered water recovered in the water storage area as backwash water when backwashing the filter media 4.

[0032] In the embodiment described above, an example was explained in which the filtration device 1 collects filtered water in a water storage section (not shown) outside the filtration tank 2, but the present invention is not limited to this example. For example, the filtration device 1 may be configured to include a water storage section for collecting filtered water within the filtration tank 2.

[0033] As described above, according to the present invention, the strainer 9 is a strainer 9 that is placed in the filter bed 3 of the filter tank 2 in the filtration device 1, and comprises a leg portion 11 that penetrates in the vertical direction, and a head portion 12 that is formed to have a larger diameter than the leg portion 11 in the horizontal direction and is provided at the upper end of the leg portion 11, and the head portion 12 has a plurality of openings 13 that open downwards and are located outside the leg portion 11 in the horizontal direction.

[0034] As a result, with the strainer 9 of the present invention, the opening 13 is inclined downward with respect to the horizontal direction, so the backwash water is ejected diagonally downward by the opening 13. Compared to backwash water ejected diagonally downward, the backwash water ejected diagonally downward has a more uniform flow distribution throughout the stacked filter media 4, and no areas with significantly low flow are created. In addition, the backwash water ejected diagonally downward can cause the filter media 4 to flow from the lower layer to the upper layer, allowing the sludge and other sediment settled in the lower layer of the filter media 4 to flow. In this way, the backwash water can be widely distributed to the filter media 4, so the filter media 4 can be cleaned efficiently, a high cleaning effect can be obtained, and the amount of uncleaned material on the filter media 4 can be reduced.

[0035] Furthermore, in the strainer 9 of the present invention, the head 12 has a curved upper surface 16 such that the outer side is lower than the central side in the horizontal direction.

[0036] This allows the backwash water flowing above the strainer 9 to flow along the upper surface 16 of the curved head 12, thereby suppressing stagnation and retention of the backwash water above the head 12. Furthermore, the curved upper surface 16 also suppresses the accumulation of sludge and other debris above the head 12. In this way, the backwash water can be widely distributed to the filter media 4, resulting in a high cleaning effect on the filter media 4.

[0037] Furthermore, in the strainer 9 of the present invention, the opening 13 is formed on the lower slope 15 of the head 12, which is inclined at an acute angle with respect to the horizontal direction.

[0038] This makes it easy to provide an opening 13 from which backwash water can be ejected diagonally downwards.

[0039] Furthermore, the filtration device 1 of the present invention comprises a plurality of strainers 9 and a filtration tank 2, wherein the plurality of strainers 9 are arranged in a staggered pattern on the filter bed 3 of the filtration tank 2.

[0040] This allows the flow of backwash water to be promoted by the other strainer 9 near the center between two adjacent strainers 9, thereby suppressing stagnation and retention of the backwash water. In this way, the backwash water can be widely distributed to the filter media 4, resulting in a high cleaning effect on the filter media 4.

[0041] Furthermore, in the filtration apparatus 1 of the present invention, the filter bed 3 of the filtration tank 2 is formed by raising the bottom of the filter bed 3 at the center between adjacent strainers 9, rather than at the position of the strainer 9.

[0042] As a result, the backwash water ejected diagonally downward from the strainer 9 can be made to flow due to the raised shape of the filter bed 3, thereby suppressing stagnation of odor backwash water near the center between adjacent strainers 9 and suppressing the accumulation of sludge and other materials. In addition, workers who perform maintenance and inspection of the various parts of the filtration device 1, such as the strainer 9, on the filter bed 3 in the filtration tank 2 can move around using the raised part of the filter bed 3 as a platform, making it easier to perform maintenance and inspection of the various parts of the filtration device 1.

[0043] Furthermore, the present invention may be modified as appropriate, provided that it does not contradict the gist or idea of ​​the invention as can be inferred from the claims and the specification as a whole. Strainers and filtration devices with such modifications are also included in the technical concept of the present invention.

[0044] [Notes on the invention] The following is an overview of the invention extracted from the above-described embodiments. Note that each configuration and processing function described below can be selected and combined as desired.

[0045] <Note 1> A strainer placed in the filter bed of a filtration tank, Legs that penetrate vertically, It comprises a head that is formed to have a larger diameter than the leg portion in the horizontal direction and is provided at the upper end of the leg portion, The strainer is characterized in that the head has a plurality of openings that open downward and are located outward from the leg portion in the horizontal direction.

[0046] <Note 2> The strainer according to Appendix 1, characterized in that the head has a curved upper surface such that the outer side is lower than the central side in the horizontal direction.

[0047] <Note 3> The strainer according to Appendix 1 or 2, characterized in that the opening is formed on the lower slope of the head which is inclined at an acute angle with respect to the horizontal direction.

[0048] <Note 4> Multiple strainers as described in any of the appendices 1 to 3, The filtration tank comprises, The filtration apparatus is characterized in that the plurality of strainers are arranged in a staggered pattern on the filter bed of the filtration tank.

[0049] <Note 5> Multiple strainers as described in any of the appendices 1 to 3, The filtration tank comprises, A filtration device characterized in that the filter bed of the filtration tank is formed by raising the bottom of the filter bed at the center between adjacent strainers, relative to the position of the strainers. [Explanation of Symbols]

[0050] 1 Filtration device 2 Filtration tank 3 Filter bed 4 Filter media 9 Strainer 11 Legs 12 Head 13 Opening 14 Bottom 15 Lower slope 16 Top side

Claims

1. A strainer placed in the filter bed of a filtration tank, Legs that penetrate vertically, It comprises a head that is formed to have a larger diameter than the leg portion in the horizontal direction and is provided at the upper end of the leg portion, The strainer is characterized in that the head has a plurality of openings that open downward and are located outward from the leg portion in the horizontal direction.

2. The strainer according to claim 1, characterized in that the head has a curved upper surface such that the outer side is lower than the central side in the horizontal direction.

3. The strainer according to claim 1, characterized in that the opening is formed on the lower slope of the head which is inclined at an acute angle with respect to the horizontal direction.

4. A plurality of strainers as described in claim 1, The filtration tank comprises, The filtration apparatus is characterized in that the plurality of strainers are arranged in a staggered pattern on the filter bed of the filtration tank.

5. A plurality of strainers as described in claim 1, The filtration tank comprises, A filtration apparatus characterized in that the filter bed of the filtration tank is formed by raising the bottom of the filter bed at the center between adjacent strainers, relative to the position of the strainers.

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