Filter cleaning device, filtration device, and filter cleaning method

Abstract

To provide a filter washing device that is improved in washing efficiency by reducing an amount of suspended matter adhering to a filter after the filter is washed, and to provide a filter device and a method for washing a filter.SOLUTION: A filter washing device includes washing liquid discharge means for discharging washing liquid toward a direction of a filter. The washing liquid uses first washing liquid and second washing liquid. The first washing liquid is raw water. The second washing liquid has concentration of suspended matter that is lower than that of the raw water.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a filter cleaning device, a filtration device, and a filter cleaning method.

Background Art

[0002] When a filter filters a mixture of solids and liquid, the solids are filtered out and accumulate on the surface of the filter, reducing the liquid permeability. Therefore, the filter is cleaned to remove the accumulated solids.

[0003] For example, Patent Document 1 describes that when filtering a mixed liquid of a suspension called slurry and liquid with a filter, in order to remove the agglomerated fine particle mass called cake on the filter, raw water is sprayed onto the filter as a cleaning liquid for cleaning.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described in Patent Document 1, when using slurry, which is raw water, as a cleaning liquid, since the cleaning liquid itself contains suspended substances, even after cleaning, the suspended substances adhere to the filter, resulting in a problem of poor cleaning efficiency.

[0006] Therefore, an object of the present invention is to provide a filter cleaning device, a filtration device, and a filter cleaning method with good cleaning efficiency that reduce the amount of suspended substances adhering to the filter after filter cleaning.

Means for Solving the Problems

[0007] As a result of diligent study on the above-mentioned problems, the inventors of the present invention have found that a filter cleaning device equipped with a cleaning liquid discharge means that discharges a cleaning liquid toward the filter, wherein by cleaning with a first cleaning liquid containing suspended solids and a second cleaning liquid with a low concentration of suspended solids, the amount of suspended solids adhering to the filter after cleaning can be reduced, and thus the present invention has been completed. In other words, the present invention relates to the following filter cleaning apparatus, filtration apparatus, and filter cleaning method.

[0008] The filter cleaning apparatus of the present invention, which solves the above problems, is a filter cleaning apparatus equipped with a cleaning liquid discharge means that discharges cleaning liquid toward the filter, wherein the cleaning liquid uses a first cleaning liquid and a second cleaning liquid, the first cleaning liquid being raw water and the second cleaning liquid being a liquid with a lower concentration of suspended solids than raw water. This filter cleaning device uses raw water as the first cleaning solution and is equipped with a cleaning solution discharge mechanism that uses a second cleaning solution with a lower concentration of suspended solids than the raw water. As a result, it has the effect of reducing suspended solids adhering to the filter more efficiently than cleaning the filter with raw water alone.

[0009] Furthermore, one embodiment of the filter cleaning apparatus of the present invention is characterized by comprising a control unit that discharges a second cleaning solution after discharging a first cleaning solution. This filter cleaning device includes a control unit that discharges a second cleaning solution after discharging a first cleaning solution. This allows for cleaning with a solution with a lower concentration of suspended solids than raw water after cleaning with the first cleaning solution, resulting in a more efficient reduction of suspended solids adhering to the filter.

[0010] Furthermore, in one embodiment of the filter cleaning apparatus of the present invention, the discharge pressure for discharging the second cleaning solution is higher than the discharge pressure for discharging the first cleaning solution. With this filter cleaning device, since the second cleaning solution contains less suspended solids compared to the raw water, even if the discharge pressure of the second cleaning solution is higher than that of the first cleaning solution, the risk of suspended solids colliding with and damaging the filter can be reduced. Therefore, the filter can be cleaned at a higher pressure, resulting in more efficient cleaning.

[0011] Furthermore, in one embodiment of the filter cleaning apparatus of the present invention, the second cleaning solution is characterized in that it is a filtrate obtained by filtering raw water. According to this filter cleaning device, since the second cleaning solution is the filtrate obtained by filtering the raw water, there is no need to supply the second cleaning solution from an external source.

[0012] Furthermore, one embodiment of the filter cleaning apparatus of the present invention is characterized in that the raw water is wastewater. With this filter cleaning device, since the raw water is wastewater, it is possible to reduce the amount of suspended solids adhering to the filter more effectively than when cleaning the filter with wastewater alone, resulting in more efficient cleaning.

[0013] Furthermore, one embodiment of the filtration apparatus of the present invention is characterized by comprising a filter cleaning device and a filter, as described in any one of claims 1 to 5. This filtration device uses raw water as the first washing solution and is equipped with a washing solution discharge mechanism that washes with a solution with a lower suspended solids concentration than the raw water as the second washing solution. As a result, it has the effect of reducing suspended solids adhering to the filter more efficiently than washing the filter with raw water alone.

[0014] Furthermore, one embodiment of the filter cleaning method of the present invention is a filter cleaning method in which a cleaning solution is discharged toward the filter, wherein the cleaning solution uses a first cleaning solution and a second cleaning solution, the first cleaning solution being raw water, and the second cleaning solution being a solution with a lower concentration of suspended solids than raw water. According to this filter cleaning method, raw water is used as the first cleaning liquid, and the filter is cleaned with a liquid having a lower concentration of suspended substances than the raw water as the second cleaning liquid. Therefore, it is possible to reduce the amount of suspended substances adhering to the filter more efficiently than when the filter is cleaned only with raw water, and there is an effect that it can be a cleaning method.

Effect of the Invention

[0015] According to the present invention, it is possible to provide a filter cleaning device, a filtration device, and a filter cleaning method with good cleaning efficiency in which the amount of suspended substances adhering to the filter is reduced after cleaning the filter.

Brief Description of the Drawings

[0016] [Figure 1] It is a schematic diagram showing the configuration of a filtration device according to the first embodiment of the present invention. [Figure 2] It is a schematic diagram showing the configuration of a filtration device according to the second embodiment of the present invention. [Figure 3] It is a schematic diagram showing the configuration of a modified filtration device according to the second embodiment of the present invention. [Figure 4] It is a schematic diagram showing the configuration of a filtration device according to the third embodiment of the present invention.

Mode for Carrying Out the Invention

[0017] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Note that the filter cleaning method of the present invention shall be replaced with the following description of the configuration and operation of the filter cleaning device. Further, this embodiment does not limit the present invention.

[0018] 〔First Embodiment〕 FIG. 1 is a schematic diagram showing the configuration of a filtration device 1A including a filter cleaning device 2A and a filter 4 according to the first embodiment of the present invention. The filtration device 1A of the present embodiment filters raw water 3 containing a liquid and suspended substances by a filter 4, and separates the raw water 3 into suspended substances and a filtrate 5 having a lower concentration of suspended substances than the raw water.

[0019] (Raw water) The raw water 3 to be filtered is a mixed liquid containing a liquid and suspended substances. As the raw water 3, in addition to a mixed liquid (slurry) in which solids are mixed with a liquid, any mixed liquid may be used. Specifically, factory wastewater, river water, sewage, tap water drainage, food factory drainage, etc. can be exemplified. Also, in tap water or desalinated water, the liquid to be filtered can be applied as the raw water. Furthermore, in the manufacture of pharmaceuticals, cosmetics, beverages or foods, the liquid to be filtered can be applied as the raw water.

[0020] More specifically, tunnel structure drainage, fresh concrete plant drainage for spraying, die slime recovery drainage, batch plant drainage, river construction dry pit drainage, deep foundation construction drainage, grouting construction drainage, shield construction drainage, shield excess muddy water, dredging landfill drainage, caisson construction drainage, site piling drainage, floor washing drainage, well point construction drainage, foundation construction yard drainage, tire washing drainage, core boring drainage, diamond cutter drainage, soil pollution excavation yard drainage, VOC decomposition washing drainage, incinerator demolition washing drainage, radioactive decontamination construction drainage, wire saw cutting construction drainage, water jet cutting construction drainage, paper mill process drainage, pulp mill process drainage, food factory washing drainage, fresh concrete plant washing drainage, concrete secondary product factory drainage, crushed stone factory yard drainage, gas washing scrubber drainage, garbage incinerator quench tower drainage, converter gas washing drainage, arc furnace gas washing drainage, silver recovery process drainage, sand washing device drainage, water washing neutralization drainage, barrel polishing drainage, electro-polishing drainage, glass polishing drainage, wet blasting drainage, spray painting booth drainage, cationic coating drainage, stainless steel pickling drainage, raw material yard drainage, raw material conveyor washing drainage, deposited dust wet recovery drainage, factory yard drainage, continuous casting drainage, rolling cooling drainage, dehumidification drain drainage, immersion cutting yard drainage, mine yard drainage, ship bottom bilge drainage, shipbuilding dock drainage, shellfish removal drainage, cooling tower blowdown drainage, dyeing factory drainage, milk plant washing drainage, tunnel wall washing drainage, building exterior wall washing drainage, car washing drainage, golf course drainage, industrial disposal site leachate, etc. can be cited. In this embodiment, the case of barrel polishing drainage containing oil and suspended substances generated in the bearing manufacturing process in a liquid will be described as an example.

[0021] Examples of barrel polishing wastewater from raw water 3 include wastewater from the initial polishing process, wastewater from the finishing process, and wastewater from the final finishing process. The states of raw water 3 and filtered filtrate 5 are illustrated in Table 1 below.

[0022] [Table 1]

[0023] (Filter cleaning device) The filter cleaning device 2A comprises a filtration container 6, a cleaning liquid discharge means 7, a pump 8, a rotating mechanism 9, a raw water storage section 10, a filtrate storage section 11, piping 12 (lines L1 to L7), and a valve 13. The filter cleaning device 2A, when cleaning the filter 4, discharges cleaning solution from the cleaning solution discharge means 7, and uses a first cleaning solution 31 (raw water 3) and a second cleaning solution 32 (filtrate 5) for cleaning. Furthermore, the filter cleaning device 2A is characterized by discharging the second cleaning solution 32 after discharging the first cleaning solution 31 to perform the cleaning.

[0024] <Filtering container> The filtration container 6 is a sealed container having an internal space capable of housing the filter 4. The filtration container 6 can be of any shape or size as long as it allows the raw water 3 to pass through the filter 4 and be separated into suspended solids and filtrate 5. The filtration container 6 has a filtrate discharge section 61 and a waste liquid discharge section 62.

[0025] ≪Filtrate discharge section≫ The filtrate discharge section 61 is a path through which raw water 3 is supplied to the internal space of the filtration container 6, and the filtrate 5 filtered by the filter 4 is discharged to the outside of the filtration container 6. It is a separate channel that prevents the raw water 3 and the filtrate 5 from mixing.

[0026] ≪Waste liquid discharge section≫ The wastewater discharge section 62 is a pathway for discharging the suspended solids filtered by the filter 4 from the internal space of the filter container 6. During filter cleaning, a concentrated mass (also called a cake) of suspended solids accumulated on the surface of the filter 4 is discharged from the wastewater discharge section 62 along with the first cleaning solution 31 and the second cleaning solution 32.

[0027] <Washing liquid dispensing means> The cleaning liquid dispensing means 7 dispenses the cleaning liquid in the direction of the filter 4. The cleaning liquid used consists of a first cleaning liquid 31 and a second cleaning liquid 32. The cleaning liquid dispensing means 7 is not particularly limited as long as it has a structure that can remove and clean the cake on the filter 4 by supplying the first cleaning liquid 31 and the second cleaning liquid 32 to the surface of the filter 4 at a constant pressure during filter cleaning. The cleaning solution dispensing means 7 is positioned to remove the entire cake from the filter 4 in the vertical direction. In this embodiment, when filtering raw water 3, the cleaning solution is supplied to the internal space of the filter container 6 via the cleaning solution discharge means 7. In other words, the supply path for the first cleaning solution 31 is the same when filtering raw water 3 and when cleaning the filter. While it is possible to have a structure in which separate paths are provided for supplying raw water 3 to the internal space of the filtration container 6 when filtering raw water 3, and for supplying the first washing liquid 31 (raw water 3) to the washing liquid discharge means 7 when cleaning the filter, the structure of the filtration container 6 is simplified by supplying both raw water 3 and the first washing liquid 31 from the washing liquid discharge means 7, as in this embodiment.

[0028] <Cleaning solution> The cleaning solution 30 includes the first cleaning solution 31 and the second cleaning solution 32. ≪First Cleaning Solution≫ The first cleaning solution 31 is raw water 3, and during filter cleaning, the raw water 3 stored in the raw water storage section 10 is used as the first cleaning solution 31. ≪Second Cleaning Solution≫ The second washing solution 32 is a liquid with a lower concentration of suspended solids than the raw water 3. Specifically, it can be the filtrate 5 obtained by filtering the raw water 3, industrial water, a mixture of raw water 3 and filtrate 5, or a mixture of industrial water and filtrate 5. In the first embodiment of the present invention, during filter cleaning, the filtrate 5 stored in the filtrate storage section 11 is used as the second cleaning solution 32. By using the filtrate 5 obtained by filtering raw water 3 as the second cleaning solution 32, there is no need to supply cleaning solution from an external source.

[0029] <pump> Pump 8 supplies raw water 3, first washing solution 31, and second washing solution 32 to the washing solution discharge means 7. The type, size, and function of the pump 8 are not particularly limited, as long as it can supply the raw water 3, the first washing solution 31, and the second washing solution 32 to the internal space of the filtration container 6 via the washing solution discharge means 7.

[0030] <Rotation mechanism> The rotating mechanism 9 is located outside the filtration container 6 and has the function of rotating the filter 4 in the circumferential direction. The rotating mechanism 9 can specifically be a motor, but is not particularly limited as long as it can rotate the filter 4 circumferentially within the internal space of the filtration container 6. As the filter 4 is rotated by the rotating mechanism 9, the first cleaning solution 31 and the second cleaning solution 32 discharged from the cleaning solution discharge means 7 are evenly supplied to the entire circumferential surface of the filter 4, allowing the entire filter to be cleaned efficiently.

[0031] <Raw Water Storage Section> The raw water storage unit 10 is a tank that stores the raw water 3 supplied from outside the filtration device 1A. The size and shape of the raw water storage unit 10 are not particularly limited, as long as it is capable of storing the raw water 3. In this embodiment, the raw water storage unit 10 is supplied with cleaning wastewater containing cake discharged from the wastewater discharge unit 62. During filter cleaning, the cleaning wastewater of the first cleaning solution 31 or the second cleaning solution 32, which contains the cake after cleaning, is returned to the raw water storage unit 10 and supplied to the filtration container 6 as raw water 3 for circulation.

[0032] <Filtrate storage section> The filtrate storage section 11 is a tank for storing the filtrate 5 filtered by the filtration device 1A. The shape and other characteristics of the filtrate storage section 11 are not particularly limited, as long as it is large enough to store the filtrate 5 and to secure the amount of the second cleaning solution 32 used when cleaning the filter.

[0033] <Piping> The piping 12 connects the filtration container 6 and the raw water storage section 10 or filtrate storage section 11, and is a pipe for moving the raw water 3 or filtrate 5. Piping 12A includes lines L1, L2, and L3. Piping 12A is a flow path connecting the raw water storage section 10 and the filtration container 6, and the filtrate storage section 11 and the filtration container 6, and is a pipe that supplies raw water 3, first washing liquid 31, and second washing liquid 32 to the washing liquid discharge means 7 of the filtration container 6. Piping 12B includes lines L4, L5, and L6. Piping 12B is a flow path connecting the filtration container 6 and the filtrate storage section 11 and the outside of the filtration device 1A (external process), and is a pipe for discharging the filtrate 5 to the filtrate storage section 11 or the outside of the filtration device 1A. The piping 12C is equipped with line L7 and is a flow path connecting the filtration container 6 and the raw water storage unit 10, and is a pipe for supplying washing wastewater to the raw water storage unit 10.

[0034] <valve> Valve 13 is installed in piping 12A, piping 12B, and piping 12C. Valve 13 can have any structure as long as it can block or allow the raw water 3, filtrate 5, first washing liquid 31, or second washing liquid 32 to pass through, and may be opened and closed by human operation or by automatic control controlled by a control unit (not shown). Valve 13 is used to switch the flow path between filtering raw water 3 in the filtration device 1A and cleaning the filter 4. Valves 13A and 13B are located in piping 12A. Valves 13C and 13D are located in piping 12B. Valve 13E is located in piping 12C.

[0035] (filter) The filter 4 is not particularly limited as long as it is a filtration member capable of separating suspended solids and liquid from the raw water 3. However, the filter 4 of the filtration device 1A is particularly suitable for cases where a cleaning method called backwashing, which involves sending cleaning solution from the downstream side (the side where the liquid of the raw water 3 passes through the filter) to the upstream side (outside the filter) where the raw water 3 is supplied to clear clogging of the filter, is not applicable, or where backwashing does not have a high cleaning effect. Specifically, a pleated filter, which is made by folding a flat filtration member multiple times to create pleats, is a suitable example. In this embodiment, the filter 4 is a cylindrical pleated filter, and the case is illustrated in which suspended solids contained in the raw water 3 are concentrated on the outer surface of the filter 4, and the filtrate 5 passes through the inside of the filter 4.

[0036] (Regarding the operation of the filtration system) Next, we will explain the operation of the filtration device 1A. First, regarding the filtration of raw water 3, valves 13A and 13C of the filtration device 1A are opened, and the other valves 13 are closed. As a result, raw water 3 is supplied to the filtration container 6. This state is called the filtration preparation step.

[0037] Then, the raw water 3 from the raw water storage unit 10 is supplied by the pump 8 to the washing liquid discharge means 7 via lines L1 and L3 of the piping 12A. The raw water 3 is supplied from the washing liquid discharge means 7 to the internal space of the filtration container 6, where the suspended matter of the raw water 3 is concentrated on the outer surface of the filter 4 to form a cake, while the liquid of the raw water 3 that has passed through the filter 4 becomes the filtrate 5.

[0038] The filtrate 5 is stored in the filtrate storage section 11 via lines L4 and L5 of the piping 12B from the filtrate discharge section 61. After a certain amount has been stored in the filtrate storage section 11, valve 13D is opened and valve 13C is closed, causing the filtrate 5 to be discharged to the next process outside the filtration device 1A via lines L4 and L6 of the piping 12B. These processes constitute the filtration process.

[0039] The raw water 3 is filtered, and when the filter 4 becomes clogged and the flow rate of the raw water 3 decreases to a certain level, the filter cleaning process is performed. The timing of the filter cleaning process can be determined by installing a flow meter at any point in the piping 12 and checking when the flow rate in the piping 12 decreases to a certain level, installing a pressure gauge at any point in the piping 12 and checking when the pressure in the piping 12 exceeds a certain pressure, measuring the time it has been processing the raw water 3 and checking when a certain amount of time has elapsed, or by visually inspecting the condition of the filter 4 by a person.

[0040] When the filter cleaning process is performed, valves 13A and 13E of the filtration device 1A are opened, and the other valves 13 are closed. Since valve 13E is open, the raw water 3 that filled the internal space of the filtration container 6 during the treatment of the raw water 3 is discharged. Furthermore, the rotating mechanism 9 is activated, causing the filter 4 to rotate circumferentially. This state is considered the washing preparation step.

[0041] Once the cleaning preparation process is complete, the first cleaning solution 31 (raw water 3) is supplied by the pump 8 to the cleaning solution discharge means 7 via lines L1 and L3 of the piping 12A. This process is referred to as the first cleaning solution discharge process. The first washing liquid 31 (raw water 3) is discharged from the washing liquid discharge means 7 toward the filter 4 in the internal space of the filtration container 6 and supplied so as to collide with the filter 4, thereby washing and removing the cake from the surface of the filter 4. The washing wastewater containing the first washing liquid 31 (raw water 3) and the cake is stored in the raw water storage section 10 via line L7 of the piping 12C.

[0042] Next, the filter 4 is washed with the first washing solution 31 to remove the cake, and then washed with the second washing solution 32. The valve 13A of the filtration device 1A is closed, and the valve 13B is open.

[0043] In this state, the second cleaning solution 32 (filtrate 5) is supplied by the pump 8 to the cleaning solution discharge means 7 via lines L2 and L3 of the piping 12A. This process is referred to as the second cleaning solution discharge process. The switching between the first cleaning fluid discharge process and the second cleaning fluid discharge process may be controlled by a control unit (not shown) or by human intervention.

[0044] The second cleaning solution 32 is discharged from the cleaning solution discharge means 7 toward the filter 4 in the internal space of the filtration container 6 and supplied so as to collide with the filter 4, thereby cleaning the surface of the filter 4. The filter 4 that has been cleaned with the first cleaning solution 31 has cake and suspended solids contained in the raw water 3, which is the first cleaning solution 31, adhering to the surface of the filter 4. Therefore, by washing the filter 4 in that state with the second washing solution 32, cake and suspended solids adhering to the filter 4 can be washed away, thereby improving the cleaning efficiency of the filter 4. Furthermore, since the second washing solution 32 has a lower concentration of suspended solids than the first washing solution 31 (raw water 3), even if the second washing solution (filtrate 5) collides with the filter during washing, it has the effect of suppressing damage to the filter 4 by suspended solids compared to the first washing solution 31. The second washing solution 32 and the washing wastewater containing cake and suspended solids are stored in the raw water storage section 10 via line L7 of piping 12C.

[0045] With the above operations, the filter cleaning is completed. The rotating mechanism 9 is stopped, and the valve 13 returns to the state of filtering the raw water 3, making it possible to perform the filtering process of the raw water 3 again.

[0046] [Second Embodiment] Figure 2 is a schematic diagram showing the configuration of a filtration device 1B equipped with a filter cleaning device 2B according to a second embodiment of the present invention. In the filtration apparatus 1B of the second embodiment of the present invention, the same reference numerals are used for the same functions and structures as in the first embodiment, and their descriptions are omitted. The second embodiment of the present invention differs from the first embodiment in that, instead of the pump 8 of the first embodiment, a pump 81 for supplying the first cleaning liquid 31 to the cleaning liquid discharge means 7 and a pump 82 for supplying the second cleaning liquid 32 to the cleaning liquid discharge means 7 are provided separately. Furthermore, the discharge pressure of the second cleaning liquid 32 discharged from the cleaning liquid discharge means 7 is higher than the discharge pressure of the first cleaning liquid 31 discharged from the cleaning liquid discharge means 7.

[0047] <Pump 81> Pump 81 is installed in line L1 of piping 12A and supplies raw water 3 and first washing liquid 31 to washing liquid discharge means 7. The pump 81 is not particularly limited in terms of type, size, or function, as long as it can supply raw water 3 or first washing liquid 31 to the internal space of the filtration container 6 via the washing liquid discharge means 7. However, a pump with a smaller flow rate than pump 82, or a pump controlled to have a smaller flow rate than pump 82, is used.

[0048] <Pump 82> The pump 82 is installed in line L2 of piping 12A and supplies the second cleaning liquid 32 to the cleaning liquid discharge means 7. The type, size, and function of the pump 82 are not particularly limited, as long as it can supply the second washing liquid 32 to the internal space of the filtration container 6 via the washing liquid discharge means 7. However, a pump with a larger flow rate than pump 81 or a pump controlled to have a larger flow rate than pump 81 is used.

[0049] As described above, because the flow rate of pump 82 is greater than the flow rate of pump 81, the filter cleaning device 2B is in a state where the discharge pressure of the second cleaning liquid 32 (filtrate 5) discharged from the cleaning liquid discharge means 7 is higher than the discharge pressure of the first cleaning liquid 31 (raw water 3) discharged from the cleaning liquid discharge means 7.

[0050] (Regarding the operation of filtration device 1B) Next, the operation of the filtration device 1B will be described. The operation that is the same as that of the filtration device 1A in the first embodiment will be omitted from the description. The operation when filtering raw water 3 is the same as that of the filtration device 1A in the first embodiment, and is also the same up to the cleaning preparation step in the filter cleaning process. Therefore, the process from the cleaning preparation step onward will be explained.

[0051] Once the cleaning preparation process is complete, the first cleaning solution 31 is supplied by the pump 81 to the cleaning solution discharge means 7 via lines L1 and L3 of the piping 12A (first cleaning solution discharge process). The first cleaning solution 31 is discharged from the cleaning solution discharge means 7 toward the filter 4 in the internal space of the filtration container 6 and supplied so as to collide with the filter 4, thereby cleaning and removing the cake from the surface of the filter 4. The cleaning wastewater containing the first cleaning solution 31 and the cake is stored in the raw water storage section 10 via line L7 of the piping 12C.

[0052] Next, the filter 4 is washed with the first washing solution 31 to remove the cake, and then washed with the second washing solution 32. The valve 13A of the filtration device 1A is closed, and the valve 13B is open.

[0053] In this state, the second cleaning liquid 32 is supplied by the pump 82 to the cleaning liquid discharge means 7 via lines L2 and L3 of the piping 12A (second cleaning liquid discharge step). The switching between the first cleaning fluid discharge process and the second cleaning fluid discharge process may be controlled by a control unit (not shown) or by human intervention.

[0054] The second washing solution 32 is discharged from the washing solution discharge means 7 toward the filter 4 in the internal space of the filtration container 6 and supplied so as to collide with the filter 4, thereby washing the surface of the filter 4. The filter 4 that has been washed with the first washing solution 31 has cake and suspended solids contained in the raw water 3, which is the first washing solution 31, adhering to the surface of the filter 4. At this time, the second cleaning liquid 32 discharged from the cleaning liquid discharge means 7 has a higher discharge pressure than the first cleaning liquid 31 discharged from the cleaning liquid discharge means 7. Therefore, cake and suspended matter adhering to the filter 4 can be washed away with the high-pressure second cleaning liquid 32, thereby further improving the cleaning efficiency of the filter 4. Furthermore, since the second washing solution 32 has a lower concentration of suspended solids than the raw water 3, even if the second washing solution 32 collides with the filter at a higher pressure than the first washing solution 31 during washing, it can more effectively suppress damage to the filter 4 due to suspended solids compared to the first washing solution 31, and the washing time can be shortened because it can be washed at a higher pressure. The second washing solution 32 and the washing wastewater containing cake and suspended solids are stored in the raw water storage section 10 via line L7 of piping 12C.

[0055] The filter cleaning is completed by the above operation. The rotation mechanism 9 is activated, and the valve 13 returns to the state where it filters the raw water 3, making it possible to filter the raw water again.

[0056] In the second embodiment of the present invention, a pump 81 and a pump 82 with a higher flow rate than pump 81 are individually provided, and an example is shown in which the discharge pressure of the second cleaning liquid 32 discharged from the cleaning liquid discharge means 7 is higher than the discharge pressure of the first cleaning liquid 31 discharged from the cleaning liquid discharge means 7. However, as shown in the modified example of the second embodiment of the present invention in Figure 3, a pump 83 controlled by a control unit 84 is installed in line L3 of piping 12A instead of the pump 8 of the first embodiment of the present invention, and the control unit 84 controls the flow rate of the pump 83 to be greater during the second cleaning liquid discharge process than during the first cleaning liquid discharge process, so that the discharge pressure of the second cleaning liquid 32 discharged from the cleaning liquid discharge means 7 is higher than the discharge pressure of the first cleaning liquid 31 discharged from the cleaning liquid discharge means 7.

[0057] [Third Embodiment] Figure 4 is a schematic diagram showing the configuration of a filtration device 1C equipped with a filter cleaning device 2C according to a third embodiment of the present invention. In the filtration apparatus 1C of the third embodiment of the present invention, the same reference numerals are used for the same functions and structures as in the first embodiment, and their descriptions are omitted. The third embodiment of the present invention differs from the first embodiment in that it separately includes a cleaning liquid discharge means 7A and a cleaning liquid discharge means 7B.

[0058] <Washing liquid dispensing means 7A> The cleaning liquid dispensing means 7A dispenses the first cleaning liquid 31 toward the filter 4. The cleaning liquid dispensing means 7A is applicable as long as it has a discharge pressure that can remove and clean the cake from the filter 4 by supplying the first cleaning liquid 31 to the surface of the filter 4 during filter cleaning. <Washing liquid dispensing means 7B> The cleaning liquid dispensing means 7B dispenses the second cleaning liquid 32 toward the filter 4. The cleaning liquid dispensing means 7B is applicable as long as it is structured in such a way that the cake on the filter 4 can be removed and cleaned by supplying the second cleaning liquid 32 to the surface of the filter 4 during filter cleaning.

[0059] The cleaning liquid dispensing means 7A and cleaning liquid dispensing means 7B share a pump 8, and the structure is applicable if, when the flow rate of the first cleaning liquid 31 supplied by the pump 8 to the cleaning liquid dispensing means 7A is the same as the flow rate of the second cleaning liquid 32 supplied by the pump 8 to the cleaning liquid dispensing means 7B, the discharge pressure of the cleaning liquid dispensing means 7B dispensing the second cleaning liquid 32 is higher than the discharge pressure of the cleaning liquid dispensing means 7A dispensing the first cleaning liquid 31. Specifically, an example is to make the nozzle opening of the cleaning liquid dispensing means 7B smaller than the nozzle opening of the cleaning liquid dispensing means 7A.

[0060] <Piping> Piping 12 is further provided with line L8 in piping 12A. Line L8 is a pipe for supplying the second cleaning liquid 32 to the cleaning liquid discharge means 7B of the cleaning liquid discharge means 7.

[0061] <valve> Valve 13 further comprises valve 13F and valve 13G. Valve 13F is open during the filtration process and the first washing liquid discharge process, and closed during the second washing liquid discharge process. Furthermore, valve 13G is closed during the filtration process and the first washing liquid discharge process, and open during the second washing liquid discharge process.

[0062] (Regarding the operation of filtration device 1C) Next, the operation of the filtration device 1C will be described. The operation of the filtration device 1C is the same as that of the filtration device 1A in the first embodiment, and, as in the first embodiment, during the filtration process, the valve 13 is operated so that raw water 3 is supplied from the washing liquid discharge means 7. Specifically, in this embodiment, filtration is performed with valves 13F and 13G opened and closed so that raw water 3 is supplied from the washing liquid discharge means 7. Furthermore, in the first cleaning fluid discharge process, the valve 13F on line L3 and the valve 13G on line L8 are switched so that the first cleaning fluid 31 is discharged from the cleaning fluid discharge means 7A, and the first cleaning fluid 31 is not discharged from the cleaning fluid discharge means 7B, and cleaning is performed. Then, in the second cleaning fluid discharge step, the valve 13F on line L3 and the valve 13G on line L8 are switched so that the second cleaning fluid 32 is not discharged from the cleaning fluid discharge means 7A, but is discharged from the cleaning fluid discharge means 7B, and cleaning is performed.

[0063] In the filter cleaning of the filtration device 1C, the second cleaning solution 32 is supplied from the cleaning solution discharge means 7B, which has a high discharge pressure. This allows the cake and suspended matter adhering to the filter 4, which has been cleaned with the first cleaning solution 31, to be washed away with the high-pressure second cleaning solution 32, thereby improving the cleaning efficiency of the filter 4.

[0064] In the first to third embodiments, a rotating mechanism 9 is provided to rotate the filter 4, thereby enabling cleaning of the entire circumferential direction. However, by providing multiple cleaning liquid discharge means 7 in the circumferential direction surrounding the filter 4, the need for the rotating mechanism 9 can be eliminated, thereby enabling cleaning of the entire circumferential direction of the filter 4.

[0065] Furthermore, in the first to third embodiments, pumps 8, 81, 82, and 83 are provided to supply the first cleaning liquid 31 or the second cleaning liquid 32 to the cleaning liquid discharge means 7, 7A, and 7B. However, it is also possible to install the raw water storage unit 10 and the filtrate storage unit 11 at a higher position than the installation positions of the cleaning liquid discharge means 7, 7A, and 7B, so that the first cleaning liquid 31 or the second cleaning liquid 32 falls by gravity and is supplied to the cleaning liquid discharge means 7, 7A, and 7B, causing the first cleaning liquid 31 or the second cleaning liquid 32 to be discharged. [Industrial applicability]

[0066] The filter cleaning apparatus, filtration apparatus, and filter cleaning method of the present invention can be used for factory wastewater, river water, sewage wastewater, drinking water wastewater, and wastewater from food processing plants. They can also be used in filtration devices during water production or water manufacturing, and in filtration devices used in the production of pharmaceuticals, cosmetics, beverages, or food products. Examples include filtering beverages or brewer's yeast. In particular, because cleaning can be done at low cost by utilizing the filtrate, it is suitable for use in factory wastewater such as barrel polishing wastewater. [Explanation of Symbols]

[0067] 1A, 1B, 1C Filtration device, 2A, 2B, 2C Filter cleaning device, 3 Raw water, 4 Filter, 5 Filtrate, 6 Filtration container, 7, 7A, 7B Cleaning liquid discharge means, 8 Pump, 9 Rotating mechanism, 10 Raw water storage section, 11 Filtrate storage section, 12, 12A, 12B, 12C Piping, 13, 13A, 13B, 13C, 13D, 13E Valves, 31 First cleaning liquid, 32 Second cleaning liquid, 61 Filtrate discharge section, 62 Waste liquid discharge section, 81 Pump, 82 Pump, 83 Pump, 84 Control unit.

Claims

1. A filter cleaning apparatus equipped with a cleaning liquid discharge means for cleaning the raw water side surface of a cylindrical filter by discharging the cleaning liquid so as to collide with the outer surface of the filter, The aforementioned cleaning solution uses a first cleaning solution and a second cleaning solution. The first washing solution is raw water, and the second washing solution is a solution with a lower concentration of suspended solids than the raw water. A filter cleaning device characterized in that the flow path for discharging the first cleaning liquid and the second cleaning liquid is the same.

2. The filter cleaning apparatus according to claim 1, further comprising a control unit that discharges the second cleaning liquid after discharging the first cleaning liquid.

3. The filter cleaning apparatus according to claim 1 or 2, characterized in that the discharge pressure for discharging the second cleaning liquid is higher than the discharge pressure for discharging the first cleaning liquid.

4. The filter cleaning apparatus according to any one of claims 1 to 3, characterized in that the second cleaning liquid is a filtrate obtained by filtering raw water.

5. The filter cleaning apparatus according to any one of claims 1 to 4, characterized in that the raw water is wastewater.

6. A filtration apparatus comprising a filter cleaning device according to any one of claims 1 to 5 and a filter.

7. A filter cleaning method that cleans the raw water side surface of a cylindrical filter by discharging a cleaning solution so as to collide with the outer surface of the filter, A filter cleaning method in which cleaning solution is discharged in the direction of the filter, The aforementioned cleaning solution uses a first cleaning solution and a second cleaning solution. The first washing solution is raw water, and the second washing solution is a solution with a lower concentration of suspended solids than the raw water. A filter cleaning method characterized by discharging the first cleaning solution and the second cleaning solution from the same flow path.

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