JP4606116B2 - Filtration device - Google Patents

Description

  The present invention relates to a filtration device, and more particularly, to a high-speed filtration device that can reliably and rapidly perform filtration of solid substances contained in raw water.

As one of the filtration devices, three or more cylindrical screens having different diameters made of an annular multilayer prepack screen assembly having a filtrate outlet are coaxially arranged adjacent to each other inside a filtration tank having a raw water inlet. There is known a high-speed filtration device in which an annular space is formed between screens to be filled, and each annular space is filled with two or more different filter media that perform different filtration functions (see, for example, Patent Document 1). By using such a cylindrical screen, the filtration area can be greatly expanded as compared with a general filtration device, so that the filtration process can be speeded up.
JP 2000-246021 A

  However, in the above-described high-speed filtration device, filtration efficiency may be reduced due to coarse solids adhering to the outer peripheral surface of the cylindrical screen. Furthermore, there is a problem that the filter medium filled in the annular space is likely to be insufficiently cleaned. It is also conceivable to install a scraper on the outer periphery of the cylindrical screen and rotate the cylindrical screen to remove coarse solid matter adhering to the outer peripheral surface with the scraper. There is a problem in that a large amount of power is required to rotate, and the structure of the bearing or the like becomes large and the manufacturing cost increases.

  Therefore, the present invention is excellent in filtration efficiency, can easily remove coarse solids adhering to the outer peripheral surface of the cylindrical screen, and can also reduce the production cost by adopting a simple structure. The object is to provide a filtration device that can be used.

In order to achieve the above object, a filtration device according to the present invention is provided with a sealed container, a cylindrical outer screen provided with the axis line oriented vertically in the sealed container, and the outer screen. An inner screen; a compression-deformable filter medium filled between the outer screen and the inner screen; a filter medium compressing means for compressing the filter medium; and for scraping off solid matter adhering to the outer peripheral surface of the outer screen. A deposit removing means, an air diffuser provided inside the sealed container, a raw water inflow portion for allowing the raw water to flow in a direction along the inner wall of the container at the lower part of the sealed container, and the treated water in the inner screen to the treated container. a treated water outlet unit to flow out from the top, and a cleaning water discharge outlet portion for discharging the cleaning effluent from the bottom of the closed container, said air diffuser means, with open path of the detergent drain outlet section, the diverging air Aeration from the means It is characterized by being drainable form a detergent drain in the closed container to increase the pressure in the more closed container.

  Furthermore, in the above-described configuration, the filtration device of the present invention is a scraper that is slidably contacted with the outer peripheral surface of the outer screen by the rotational movement or linear movement driven by the driving means. The floating body is filled between the airtight container and the outer screen and is slidably brought into contact with the outer peripheral surface of the outer screen by the flow of raw water during the filtration step or washing water during the washing step.

  Further, the filter medium compressing means moves in the axial direction between the outer screen and the inner screen by a plurality of cylinders, and compresses and relaxes the filter medium in a range of 10 to 50% with respect to the filling volume. The air diffusion means is provided at least at the bottom between the outer screen and the inner screen.

Furthermore, it said air diffuser means, in the path for supplying the aeration air to the aeration unit, the water vapor, the path for injecting a sterilizing agent or cleaning agent is characterized in that it is connected.

  Further, the filter medium is a fibrous or sponge-like filter medium, and further, the filter medium has a large gap and a large deformation amount due to pressurization, and a filter medium that has a small gap and small deformation amount due to pressurization. It is characterized by having a combined structure.

  According to the filtration device of the present invention, the filter medium and the outer peripheral surface of the outer screen can be reliably washed, and the compact and economical high-speed filtration can be stably performed over a long period of time. Costs and operating costs can be reduced. For example, a filtration area several times as large as that of a conventional filtration device having an equivalent size can be obtained.

  Furthermore, the centrifugal separation effect is obtained by flowing the raw water in the direction along the inner wall of the container from the raw water inflow portion, and the screen effect on the outer screen is also obtained. In addition, the deposit removal for cleaning the outer peripheral surface of the outer screen is achieved. Since the means is provided, it is not necessary to provide a pretreatment device in the preceding stage of the filtration device. Therefore, it is possible to reduce the size of the entire filtration equipment or improve the capacity.

  Thus, the filtration processing capacity can be increased by several tens of times in the filtration equipment of the same size due to the increase in the filtration area and the improvement of the equipment capacity. Therefore, compact and economical high-speed filtration can be applied to applications where various types of filtration devices have been used in the past, such as tertiary treatment of sewage, countermeasures for overflowing rainwater in combined sewers, measures against blue water such as lakes and red tides, etc. Processing can be performed, and the equipment cost and operation cost can be greatly reduced. Furthermore, the filtration performance can be further improved by appropriately adding conventionally used metal-based flocculants such as PAC, band, polyiron, and various flocculants such as organic polymers to the raw water. It is also possible to reduce the amount of washing waste water by combining floating separation and concentration and dehydration equipment.

  1 to 6 show a first embodiment of the filtration device of the present invention. FIG. 1 is a longitudinal sectional view of the filtration device, FIG. 2 is a transverse sectional view of the filtration device, and FIG. 3 is a plan view of a scraper. FIG. 4 is a perspective view showing an example of a filter medium, FIG. 5 is a schematic system diagram showing an example of a filtration facility provided with a filtration device, and FIG. 6 is a process diagram showing an example of an operation process in the filtration facility having the configuration shown in FIG. It is.

  First, a filtration device 10 shown in this embodiment includes a substantially cylindrical sealed container (casing) 11, a cylindrical outer screen 12 provided inside the sealed container 11, and an inside of the outer screen 12. The cylindrical inner screen 13 is arranged, and the axis of each cylindrical body is coaxially arranged in the vertical direction. In the lower part of the sealed container 11, a raw water inflow portion 14 is provided for allowing the raw water to flow into the sealed container 11 in the direction along the inner wall of the container, that is, in the container tangential direction in this embodiment. The bottom of the container is provided with a washing drainage outlet 15 for allowing the washing drainage to flow out from the lower part of the container, and the inner screen 13 receives the treated water flowing into the inner screen 13 at the upper part of the sealed container 11. A treated water outflow portion 16 is provided to flow out from the waste water.

  The outer screen 12 has a peripheral surface (body) formed by a cylindrical wedge wire screen 12a, and both ends of the outer screen 12 are closed by end plates 12b and 12b. The interval (opening) is set to about 0.2 to 5.0 mm according to the type of filter medium and the properties of raw water. The inner screen 13 is in the form of a pipe provided with a large number of water passage holes 13a, and penetrates the upper end plate of the outer screen 12 and the center of the top plate of the sealed container 11 in an airtight and watertight state. The water passage hole 13a of the inner screen 13 is formed in a size and shape that does not allow the filter medium to pass or be blocked by the filter medium during operation, and allows the filtration process in the compressed state of the filter medium to be performed at the upper portion of the inner screen. It is not provided on the side.

  In addition, the outer screen 12 and the inner screen 13 can employ | adopt arbitrary structures, if it has a water flow structure which does not let a filter medium pass. For example, the outer screen 12 can have a pipe shape having a large number of water passage holes similar to the inner screen 13, for example, a punching metal formed into a cylindrical shape. A wedge wire screen similar to the screen 12 can be used. Further, the shape of the inner screen 13 is not limited to a cylindrical (pipe) shape.

  On the outer periphery of the outer screen 12, it is driven by a driving means such as a motor 17 between the hermetic container 11 and the outer screen 12 as a deposit removing means, and rotates and moves in sliding contact with the outer peripheral surface of the outer screen 12. A scraper 18 is provided for scraping off the solid matter adhering to the outer peripheral surface of the outer screen 12. As shown in FIG. 3, the scraper 18 is held by a ring-shaped or cylindrical holding member 19 in a direction parallel to the cylinder axis at intervals of 90 degrees, and the rotation of the motor 17 starts from the pinion 17a. By being transmitted to 19 internal gear 19a, it rotates in one direction or reciprocates to scrape off the solid matter on the outer peripheral surface of outer screen 12.

  In addition, between the outer screen 12 and the inner screen 13, a filter medium 21 (see FIG. 4) that can be compressed and deformed is filled, and a filter medium compressing means 22 that compresses the filter medium 21 downward from above is provided. It has been. As the filter medium 21, a filter medium which can be mainly compressed and deformed can be selected and used appropriately. However, in order to increase the trapped amount of turbidity, it is preferable to use a fibrous or sponge-shaped filter medium. As shown in FIG. 4, the sparse filter medium 21a has a large amount of voids for capturing turbidity and has a large amount of deformation due to pressurization, and a small amount of voids for capturing turbidity but has a small amount of deformation due to pressurization. The filter medium 21 having a structure in which the filter medium 21b is combined with the filter medium 21b is optimal. In addition, by using a filter medium 21 having a specific gravity of around 1, the filter medium 21 can be dispersed on average in the space between the outer screen 12 and the inner screen 13, so that a short-circuit current is generated. Can also be prevented.

  Since the fibrous or sponge-like filter medium has a higher porosity than filter media such as silica sand and anthracite, which are generally used as filter media, it captures solid matter (turbidity) per unit volume. The amount increases significantly. However, a filter medium having a large porosity has a problem that it is likely to be deformed (compressed) due to an increase in pressure. That is, when the filtration resistance increases with the continuation of the filtration, there is a problem that the filter medium is compressed and the effective voids are reduced, and the pressure is further increased rapidly. On the other hand, a dense filter medium with a small porosity has a problem that the amount of trapped suspended matter is small because the voids inside the filter medium are small. In order to exhibit the characteristics of various filter media more effectively, as described above, a filter media having a structure in which a loose filter media 21a and a dense filter media 21b are bonded together is optimal.

  Various materials and combinations can be used as a filter medium having such a structure, but considering the chemical resistance, heat resistance, physical strength, specific gravity, etc., regular polyester fibers and low melting point polyester fibers are mixed. Those that are heat-sealed are preferred. For example, the sparse filter medium 21a uses relatively thin fibers of about 6 to 10 denier and is formed into a sheet shape having a thickness of about 2 to 5 mm by reducing the packing density, and the dense filter medium 21b has about 10 to 20 denier. Using relatively thick fibers, the packing density is increased to form a sheet having a thickness of about 2 to 5 mm. And it is good to use as a filter material what was punched in the square shape of about 5-20 mm, after creating these two sheets one by one and producing the sheet | seat of 2 layers structure. Alternatively, a sheet having a three-layer structure in which a dense sheet is sandwiched therebetween and a sparse sheet on both sides may be formed and punched out to form a filter medium. In addition, it is more effective to finish the surface to be uneven by pressing it with an uneven roller when creating a sheet having a two-layer or three-layer structure.

  The low-melting-point polyester fiber may be a single polyester fiber, but a composite polyester fiber having a binder function in which polyester is used as a core and polyethylene or the like is disposed around the polyester may be used. Moreover, even if it uses a polypropylene fiber instead of a polyester fiber, a favorable filter medium can be obtained by the same method as the case of a polyester fiber. Furthermore, it is also possible to mix polyester fiber and polypropylene fiber. Further, not only heat fusion but also a method generally used in nonwoven fabric production such as needle punching, chemical bonding, or a combination thereof can be adopted as long as sufficient strength is obtained.

  The filter medium compressing means 22 has an insertion port 23a for the inner screen 13 in the center, a disk-shaped pressing member 23 arranged in a direction crossing the cylinder, and a plurality of moving the pressing member 23 in the cylinder axis direction. The cylinder 24 is actuated to expand and contract the rod 24a that penetrates the top plate of the sealed container 11 in an airtight and watertight state, and moves the pressing member 23 to change the compression state of the filter medium 21. It can be changed. The number of cylinders 24 is arbitrary, and may be one or two, but three or more cylinders are arranged at equal intervals on the circumference and interlocked so that the filter medium 21 is uniformly compressed and relaxed by the pressing member 23. be able to. The filter medium compressing means 22 is not limited to the pressing member 23, and a balloon, a bellows, or the like is disposed between the outer screen 12 and the inner screen 13, and compressed air is introduced into these to expand them. A structure for compressing the filter medium can also be adopted.

  The compression rate of the filter medium 21 can be appropriately set depending on the properties of the raw water and the filter medium 21, but it is preferably formed so that it can be compressed by about 10 to 50% with respect to the filter medium filling volume. Then, since the filtration area becomes too small with respect to the size of the apparatus, the filtration efficiency is lowered, and a compression rate of less than 10% cannot sufficiently obtain the effect of compressing the filter medium.

  Furthermore, air diffusers 25a, 25b, and 25c constituting air diffuser are provided at the bottom of the sealed container 11, the bottom between the outer screen 12 and the inner screen 13, and the bottom of the inner screen 13, respectively. Each of the air diffusers 25a, 25b, 25c is connected to a blower 27 for supplying compressed air via an air supply path 26, and is also supplied with a cleaning agent supply unit 29 via a cleaning path 28 branched from the air supply path 26. It is connected to the.

  In addition, when the purpose is only to flush the filter medium 21, it is sufficient to provide the air diffusion tube 25 b at the bottom between the outer screen 12 and the inner screen 13. In addition, by providing the diffuser tube 25a at the bottom of the hermetic container 11, solids or the like attached to the outer peripheral surface of the outer screen 12 can be removed by air washing. Furthermore, by providing the diffuser pipe 25c at the bottom of the inner screen 13, the water passage hole 13a can be washed with air.

  The filtration device 10 formed in this way can be incorporated into a filtration facility as shown in FIG. 5 and can be continuously filtered by repeating the steps shown in FIG. In addition, illustration of the detail of the filtration apparatus 10 is abbreviate | omitted in FIG.

  First, in Step 101 of the filtration process, only the valve 16V of the path connected to the treated water outflow portion 16 is opened and the raw water pump 51 is operated, and the raw water flowing into the raw water tank 53 from the raw water inflow path 52 is converted into the raw water. The pump 51 passes through the check valve 14V and flows from the raw water inflow part 14 to the lower part of the sealed container 11 at a predetermined pressure. At this time, raw water is introduced into the lower part of the cylindrical sealed container 11 in the tangential direction to the lower part of the container. By forming the swirl flow, the centrifugal force can separate sand and impurities with large specific gravity and settle to the bottom of the tank, thereby reducing the burden on the outer screen 12 and the filter medium 21.

  When the raw water that has flowed into the sealed container 11 passes through the outer screen 12, large impurities are captured, and the raw water passes through the layer of the filter medium 21 filled between the outer screen 12 and the inner screen 13. Fine suspended components in water are captured by the filter medium 21 and separated. In this filtration step, the filter medium compression means 22 operates in the filter medium compression direction to compress the filter medium 21 in a range of 10 to 50% with respect to the filling volume. The treated water from which the suspended components have been filtered out passes through the inner screen 13 and flows out to the upper treated water outflow portion 16 and is temporarily stored in the treated water tank 54 through the valve 16V. leak.

  Further, during the filtration step, the motor 17 of the deposit removing means is appropriately operated to bring the scraper 18 into sliding contact with the outer peripheral surface of the outer screen 12 to scrape off foreign matters captured on the outer peripheral surface of the outer screen 12. . The scraper 18 may be operated continuously or intermittently according to the amount of contaminants to be captured.

  In the washing operation of the filtration device 10, the filter medium expansion process in step 103 is performed according to the washing start command in step 102, the raw water pump 51 is stopped, the valve 16 </ b> V of the treated water outflow portion 16 is closed, and the filter medium compression means 22 is The filter medium 21 is operated in the direction of expansion of the filter medium, and the filter medium 21 is expanded to the filled volume, more preferably to the volume that allows about 10 to 30% of the fluidization space in addition to the filled volume. The cleaning start command in step 102 is automatically set by detecting a rise in the pressure of the raw water inflow pipe, an increase in the differential pressure between the raw water inflow part and the treated water outflow part, an increase in turbidity of the treated water, etc. Can be done automatically.

  Subsequently, the valve 15V of the washing drainage outflow portion 15 is opened by the pre-washing draining process in step 104, and the water in the sealed container 11 is discharged from the washing drainage outflow portion 15 to the washing drainage tank 56 along with the precipitate. Further, in the air washing step of step 105, the blower 27 starts operation and the valve 26V of the air supply path 26 is opened, and air washing from the air diffusion means 25 into the sealed container 11 is performed. During the water draining process or the air washing process, the valve 31V of the intake / exhaust passage 31 provided in the top plate portion of the sealed container 11 is opened as necessary to suck and exhaust the air in the sealed container 11.

  Subsequently, when the drain process of step 106 is started and the valve 31V of the intake / exhaust passage 31 is open, when the valve 31V is closed, the air is supplied into the sealed container 11 from the blower 27 for air washing. The internal pressure increases, and the water (cleaning drainage) in the sealed container 11 is forcibly discharged from the cleaning drainage outlet 15 toward the cleaning drainage tank 56 by the air pressure. In this way, the waste water in the airtight container 11 is pushed out by the pressure of the air for air washing supplied into the airtight container 11 so that the waste water is discharged from the airtight container 11 in a shorter time than the normal gravity drainage. can do. Thereby, the time of a washing | cleaning process can be shortened, the time of a filtration process can be lengthened, and the filtration efficiency in a filtration apparatus can be improved.

  Furthermore, even if the cleaning drainage tank 56 is disposed at the same level as the sealed container 11 or the cleaning drainage tank 56 is disposed at a high position, the cleaning drainage in the sealed container 11 can be sent to the cleaning drainage tank 56. Since there is no restriction on the installation location of the sealed container 11 and the cleaning drainage tank 56, and the effective water depth of the cleaning drainage tank 56 can be increased, the size of the filtration facility can be reduced.

  Next, the process proceeds to a rehydration step of step 107, the valve 15V of the washing drainage outflow portion 15 is closed and the valve 31V of the intake / exhaust passage 31 is opened, and the raw water in the raw water tank 53 is fed by the raw water pump 51 into the raw water inflow portion 14. Is introduced into the sealed container 11. At the same time, the blower 27 may be operated to perform air washing.

  After the air washing process in step 105, the drain process in step 106, and the rehydration process in step 107 are repeated a predetermined number of times by the counter in step 108, the water discarding process in step 109 is performed. In the draining step, the raw water pump 51 is operated with only the valve 32V provided in the drainage path 32 branched from the treated water outflow part 16 being opened, and the raw water is supplied into the sealed container 11 in the same manner as the normal filtration equipment. Then, the same operation as in the filtration step is performed until the turbidity of the waste water (filtered water) flowing out from the waste water path 32 becomes equal to or lower than the predetermined turbidity. The drainage path 32 can be provided at an arbitrary position between the sealed container 11 and the valve 16V of the treated water outflow portion 16, and when the intake and exhaust in the sealed container 11 can be performed by the drainage path 32. Can also be used as the intake / exhaust passage 31.

  When the draining process is completed, the process proceeds to the filter medium compression step of Step 110, and the filter medium compression means 22 is operated in the filter medium compression direction to compress the filter medium 21 by a predetermined amount. When the turbidity increased by the turbidity squeezed out from the filter medium compressed in the filter medium compression process is equal to or lower than the predetermined turbidity, the re-watering process in step 111 is performed. The valve 32V is closed, the valve 16V of the treated water outflow part 16 is opened, and the process returns to the filtration step of Step 101. Filtration can be continuously performed by sequentially repeating each of these steps.

  As described above, the filter medium compressing means 22 can capture the turbidity more reliably by appropriately compressing the filter medium in the filtration process, and release the compression of the filter medium to be in a relaxed state in the washing process. Thus, the trapped turbidity can be easily discharged. Furthermore, by carrying out air washing with air diffused from the air diffuser means 25 while the filter medium is relaxed, a strong stirring force can be obtained and the filter medium can be effectively stirred and mixed. It can be performed more efficiently. In addition, the turbid matter taken into the filter medium can be squeezed out by strongly compressing the filter medium with the filter medium compression means 22.

  Further, a backwash path 34 provided with a washing water pump 33 is provided, and the treated water is caused to flow back from the inner screen 13 toward the outer screen 12 at an appropriate time during washing so that the filter medium is backwashed. It can also be set. Further, by injecting water vapor, a sterilizing agent, a cleaning agent, and the like from the cleaning agent supply unit 29 into the sealed container 11 through the cleaning path 28, the air supply path 26, and the air diffuser 25, the filter medium is more efficiently cleaned. It is possible to sterilize bacteria trapped by the filter medium 21.

  Thereby, it is possible to reliably wash biological slime, oil, and the like that accumulate inside the filter medium, which is difficult to wash by a normal washing method. Although it is not necessary to frequently perform chemical cleaning of filter media using water vapor, sterilizing agent, cleaning agent, etc., it is effective to perform it once every three months to once a year. As the sterilizing agent and cleaning agent, acids, alkalis, sodium hypochlorite, hydrogen peroxide, surfactants and the like can be used. Further, depending on the raw water, the filter medium may supplement pathogenic microorganisms such as Cryptosporidium and Giardia, and it may not be preferable to drain them as they are, but the sealed container 11 and the screens 12 and 13 are resistant to heat. By using a material excellent in chemical resistance, these can be sterilized efficiently by injection of high-temperature steam.

  7 and 8 show a second embodiment of the filtration device of the present invention. FIG. 7 is a longitudinal sectional view of the filtration device, and FIG. 8 is a plan view of the scraper. In the following description, the same components as those in the filtration device shown in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The filtration apparatus shown in this embodiment is a ring-shaped scraper 42 that is driven by a driving means such as a cylinder 41 between the hermetic container 11 and the outer screen 12 as a deposit removing means and linearly moves in the cylinder axis direction. Is arranged. A plurality of scrapers 42 are held by rod-like holding members 43 provided in a direction parallel to the cylinder axis at appropriate intervals, and the rods of the cylinders 41 arranged along the outer peripheral surface of the sealed container 11. By continuously expanding or contracting 41a, the scraper 42 reciprocates in the vertical direction together with the connecting member 43a and the holding member 43, slidably contacts the outer peripheral surface of the outer screen 12, and adheres to the outer peripheral surface of the outer screen 12. Scrap off. The solid substance scraped off passes between the outer periphery of the scraper 42 and the inner peripheral surface of the sealed container 11 and settles down to the bottom of the container.

  The cylinder 41 can be shared with the cylinder 24 of the filter medium compressing means 22, and is formed so as to move the scraper 42 up and down in conjunction with the vertical movement of the pressing member 23 when compressing and relaxing the filter medium. You may make it scrape off the solid substance adhering to the outer peripheral surface of the outer screen 12 in the said filter medium expansion | swelling process and filter medium compression process. Further, as shown in the present embodiment, by disposing the cylinder 41 as the driving means on the outer peripheral portion of the sealed container 11, the cylinder 24 of the filter medium compressing means 22 is also disposed on the outer peripheral portion of the sealed container 11. Thus, the height of the filtration device can be greatly reduced.

  The drive means for the scraper can adopt any drive system such as electric, pneumatic, hydraulic, etc., and the power transmission mechanism can also adopt an appropriate structure, and any drive means can be used in accordance with the operation direction of the scraper. Selectable can be used. Further, in the ring-shaped scraper as described above, by attaching a float (buoy) or the like to the scraper, the scraper is moved up and down depending on the water level in the sealed container 11 in the water draining process or the rehydration process. It is also possible to form so as to scrape off the solid matter adhering to the outer peripheral surface of the screen 12.

  9 and 10 show a third embodiment of the filtration device of the present invention. FIG. 9 is a longitudinal sectional view of the filtration device, and FIG. 10 is a plan view of a perforated plate. The filtration device shown in the present embodiment fills the floating body 45 between the sealed container 11 and the outer screen 12 as an adhering matter removing means, and prevents the floating body 45 from flowing out at the upper and lower ends of the outer screen 12. For this purpose, a perforated plate 46 and a net are provided. The floating body 45 has an appropriate size and specific gravity. Specifically, the floating body 45 has a specific gravity of about 0.9 to 1.1 and has a diameter of 20 to 100 mm in the shape of a ball, cylinder, cube, or the like. The body can be used. The floating body 45 may flow or vibrate depending on the flow of raw water during the filtration process, the flow of water during the draining process during the cleaning process, the flow of cleaning water during the rehydration process, and the flow of gas and liquid during the air washing process. By doing so, the floating body 45 collides with the outer peripheral surface of the outer screen 12 and scrapes off the solid matter adhering to the outer peripheral surface of the outer screen 12. By using such a floating body 45, the apparatus configuration can be simplified as compared with the case where a mechanical scraper is provided.

It is a longitudinal cross-sectional view which shows the 1st form example of the filtration apparatus of this invention. It is a cross-sectional view of a filtration apparatus. It is a top view of a scraper. It is a perspective view which shows an example of a filter medium. It is a schematic system diagram which shows an example of the filtration equipment which installed the filtration apparatus. It is process drawing which shows an example of the driving | running process in a filtration installation. It is a longitudinal cross-sectional view which shows the 2nd form example of the filtration apparatus of this invention. It is a top view of a scraper. It is a longitudinal cross-sectional view which shows the 3rd example of a filtration apparatus of this invention. It is a top view of a perforated plate.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Filtration apparatus, 11 ... Sealed container, 12 ... Outer screen, 12a ... Wedge wire screen, 12b ... End plate, 13 ... Inner screen, 13a ... Water passage hole, 14 ... Raw water inflow part, 15 ... Washing drainage outflow part, 16 ... treated water outflow part, 17 ... motor, 18 ... scraper, 19 ... holding member, 21 ... filter medium, 21a ... sparse filter medium, 21b ... dense filter medium, 22 ... filter medium compression means, 23 ... pressing member, 24 ... cylinder, 25 ... Air diffuser, 25a, 25b, 25c ... Air diffuser, 26 ... Air supply path, 27 ... Blower, 28 ... Cleaning path, 29 ... Cleaning agent supply part, 31 ... Intake / exhaust path, 32 ... Waste water path, 33 ... Washing water pump, 34 ... Backwashing path, 41 ... Cylinder, 42 ... Scraper, 43 ... Holding member, 45 ... Floating body, 46 ... Perforated plate, 51 ... Raw water pump, 52 ... Raw water inflow path, 53 ... Aquarium, 54 ... treatment water tank, 56 ... cleaning sump

Claims (8)

A sealed container, a cylindrical outer screen provided in the sealed container with the axis line oriented vertically, an inner screen provided in the outer screen, and between the outer screen and the inner screen Provided in the inside of the hermetically sealed container, the filter medium that can be compressed and deformed, the filter medium compressing means for compressing the filter medium, the deposit removing means for scraping off the solid matter adhering to the outer peripheral surface of the outer screen, Aeration means, raw water inflow portion for allowing raw water to flow into the lower part of the sealed container in a direction along the inner wall of the container, treated water outflow part for allowing treated water in the inner screen to flow out from the upper part of the sealed container, and lower part of the sealed container A cleaning drainage outflow portion for allowing the cleaning drainage to flow out from the air, and the air diffuser increases the pressure in the sealed container by the air diffused from the air diffuser with the passage of the cleaning drainage outflow portion opened. Wash in sealed containers Filtration apparatus characterized by being drainable formed drainage. 2. The filtration apparatus according to claim 1, wherein the deposit removing means is a scraper that is driven by a driving means to make a rotational motion or a linear motion, and is in sliding contact with the outer peripheral surface of the outer screen. The adhering matter removing means is a floating body that is filled between the sealed container and the outer screen and is in sliding contact with the outer peripheral surface of the outer screen due to the flow of raw water during the filtration step or washing water during the washing step. The filtration device according to claim 1. The filter medium compressing means is formed of a disk-shaped member that moves in the axial direction between the outer screen and the inner screen by a plurality of cylinders, and compresses and relaxes the filter medium in a range of 10 to 50% with respect to the filling volume. The filtration device according to any one of claims 1 to 3, wherein the filtration device is provided. The filtration device according to any one of claims 1 to 4, wherein the air diffuser is provided at least at a bottom portion between the outer screen and the inner screen. The said aeration means has the path | route which inject | pours water vapor | steam, a sterilizing agent, or a washing | cleaning agent with the path | route which supplies the air for aeration to this aeration means, The any one of Claim 1 thru | or 5 characterized by the above-mentioned. 2. The filtration device according to item 1. The filtration device according to any one of claims 1 to 6 , wherein the filter medium is a fibrous or sponge-like filter medium. The filter media, the gap is large, the amount of deformation due to pressurization large filtration media according to claim 1 to 6 voids is small, characterized in that the amount of deformation due to pressure has a structure in which a combination of a small filter medium The filtration apparatus of any one of these.

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