JP5623579B2 - Filtration device and backwashing method of filter medium - Google Patents

Description

  The present invention relates to an apparatus for capturing turbidity from irrigation water, waste water or other raw water and filtering the raw water, and a method for backwashing a filter medium used in the filtration apparatus.

  As a filtration device in which a filter medium is arranged in a casing, a filter medium longer than the separation distance between the two porous plates is provided between the porous plate constituting the filter medium support bed and the upper porous plate facing the porous plate. There existed what was set as the structure provided (refer patent document 1). In this filtering device, the filter medium is composed of a core string and a turbidity trapping material protruding to the peripheral side, one end of the core string is fixed to the upper porous plate, and the other end is fixed to the porous, At the time of filtration operation (at the time of press-fitting raw water), the filter medium became a compacted state due to the inflow of the raw water, and the core string was extended at the time of backwashing. However, since both ends of the core string are fixed to the upper perforated plate and the perforated plate, respectively, the compacted state of the filter medium during the filtering operation does not become an extreme state, and the turbidity trapping material during backwashing is not The upper perforated plate was not touched.

  However, the above filtration device allows the filter medium to extend in the longitudinal direction in a casing having a uniform inner diameter, so the distance between adjacent filter media is not changed even during backwashing. There was a problem that an appropriate amount of backwash water could not be passed between the filter media to be obtained, and a sufficient backwash effect could not be obtained.

  Therefore, the applicants of the present application have a casing composed of a large-diameter upper casing and a small-diameter lower casing, and concentrates the filter medium on the lower casing during processing operations and moves the filter medium to the upper casing during backwashing. An apparatus has been proposed (see Patent Document 2).

JP 2002-45612 A JP 2012-196292 A

  The above filtration device arranges the filter medium between the upper porous plate and the lower porous plate, connects one end of the core string constituting the filter medium to the upper porous plate, and connects the other end to the lower porous plate. Since the upper perforated plate and the lower perforated plate are respectively movable in the vertical direction, the entire filter medium is lowered and stored in the lower casing during the filtration operation, and backwashed. Sometimes it was able to rise and move into the upper casing. And since the filter medium moved into the upper casing has a large peripheral inner diameter, a large gap can be generated between adjacent filter media, and the backwashing effect can be improved. In addition, when the rise of the lower porous plate is large, the distance to the upper porous plate does not change, so by providing a stopper for stopping the rise of the lower porous plate at a predetermined position, the distance between the two is reduced. It is also possible to extend the filter media by expanding.

  However, the backwashing of the filter medium by the above-described filtration device is to press-flush backwash water in the reverse direction from the discharge port, and remove suspended matter trapped by the continuously flowing backwash water from the filter medium. In such a method, not only a large amount of backwash water is required, but also the water used for backwashing contains turbidity, so that the water can be drained without being reused. Had been treated as.

  The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a filtration device capable of obtaining a sufficient backwash effect with a small amount of backwash water, and the filtration device. It is to provide a backwashing method using.

  Therefore, the present invention according to the filtration device is a filtration device comprising a cylindrical casing capable of passing raw water, and a filter medium provided inside the casing and having a core string and a turbidity trapping material protruding around the core string. In, the base end side perforated plate that can be installed in the vicinity of the downstream side opening of the casing, and a support column supported by the base end side perforated plate and having an axial center disposed along the water flow direction in the casing, An upstream perforated plate that is supported in a bowl shape with respect to the support column and is provided so as to be able to advance and retreat in the axial direction of the support column, and is disposed between the base end side porous plate and the upstream perforated plate, A downstream perforated plate that is supported in a hook shape while being supported so as to be able to advance and retreat in the axial direction of the support column, and one end of the core cord of the filter medium is connected to the upstream perforated plate, The end is connected to the downstream perforated plate, Is shall.

  According to the above configuration, since the upstream perforated plate and the downstream perforated plate are both in a state where they can advance and retreat with respect to the support, during backwashing, by raising both the perforated plates, By changing the distance between the two perforated plates, the core cord of the filter medium can be expanded and contracted. In order to change the distance between the upstream perforated plate and the downstream perforated plate, only the upstream perforated plate needs to be advanced and retracted. The distance with the downstream porous plate will change. At this time, the downstream porous plate moves forward and backward due to expansion and contraction of the filter medium (especially the core string), but the filter medium (particularly the core string) is flexibly deformed, so that the distance between the two porous plates is changed. Is possible. In addition, in the above, advancing / retreating means to advance toward the flow direction of the raw water and to reverse in the opposite direction, and when the core string expands / contracts, the core string itself physically expands / contracts. In addition to the case, it also means that the overall length of the core string is changed by changing the length of the core string from a relaxed state to a tensioned state.

  In the above invention, the support column includes a sheath member that appropriately covers a range from the upstream end, the upstream perforated plate is supported by the sheath member, and the sheath member is slid in the axial direction. It can be set as the structure by which this upstream perforated board was provided so that it could advance / retreat.

  In the case of the above configuration, since the upstream perforated plate is supported by the sheath member, only the upstream perforated plate can be easily moved by sliding the sheath member in the advance / retreat direction (axial direction of the support column). Can be advanced or retreated. Further, since the sheath member is arranged so as to cover the support column, the sliding in the forward / backward direction is necessarily in the direction along the support column, and the distance from the downstream porous plate supported by the support column. Can be easily changed in the axial direction of the column.

  Furthermore, in the above invention, the downstream porous plate includes a through hole that can be loosely fitted to the support column, and the support column includes a stopper portion that restricts a position where the downstream porous plate can advance and retreat. It can be configured.

  According to the said structure, a downstream porous plate can be advanced / retreated along the support | pillar penetrated by a through-hole. Further, when the upstream porous plate moves (retreats) by restricting the position where the downstream porous plate should move back and forth, in particular, the position where the downstream porous plate moves (retreats) toward the upstream perforated plate, the movement is accompanied by the movement. Thus, the retracted position when moving is limited, and the distance between the upstream perforated plate and the downstream perforated plate can be greatly expanded. Thereby, the filter medium (especially core string) installed in the middle of both perforated plates can be extended greatly.

  And as a casing in each said invention, it is preferable to set it as the structure which makes a downstream flow-path cross-sectional area smaller than an upstream flow-path cross-sectional area.

  According to such a configuration, during the filtration operation, the upstream perforated plate and the downstream perforated plate both move (advance) to the downstream side, thereby allowing the filter medium to be stored in the downstream side having a small flow path area. It is possible to improve the trapping effect of the turbidity by the filter medium (particularly the turbidity trapping material). On the other hand, at the time of backwashing, by moving (retracting) the upstream perforated plate and the downstream perforated plate to the upstream side, the filter medium can be moved to the upstream side having a large channel area. By performing backwashing on the upstream side having a large channel area, the filter medium (especially turbidity trapping material) can be brought into contact with the backwash water in a state where the interval between adjacent individual filter media (particularly the core string) is widened. .

  Furthermore, as the casing in the invention having the above-described configuration, an intermediate flow path having an inner surface formed in a taper shape between a downstream flow path having a small flow cross-sectional area and an upstream flow path having a large flow cross-sectional area is provided. It can be set as the structure provided.

  According to the above configuration, at the time of the filtration operation, part or all of the filter medium can be stored in the intermediate flow path, whereby the flow path cross-sectional area of the casing in which the filter medium is stored is along the direction of water flow. Therefore, the entire filter medium can be arranged so that the gap between adjacent filter media (especially core strings) is gradually narrowed. In this way, by gradually narrowing the gap between adjacent individual filter media (particularly the core string), it is possible to capture from a relatively large turbidity to a fine turbidity in a stepwise manner.

  On the other hand, the present invention according to the backwashing method of the filter medium is a backwashing method of the filter medium used in the invention according to the above-described filtration device, and the backwash water is caused to flow into the casing from the downstream side, The backwash water is stored in the casing in an appropriately water level, and the filter medium is expanded and contracted by forcibly moving the upstream perforated plate back and forth.

  According to the said structure, a filter medium can be wash | cleaned in the state which stored the backwash water in the casing. That is, a predetermined amount of backwash water is stored in the casing, and by moving the upstream perforated plate back and forth, part of the filter medium is moved (vibrated) in water, and is located upstream. Part of the filter medium advances and retreats in the vicinity of the water surface (or between the water and the upper surface of the water), and the backwash water can be vigorously brought into contact with the filter medium (particularly the turbid trapping material) by the vibration. The turbidity can be removed from the filter medium (particularly the turbidity trapping material) by contacting the backwash water at this time. The appropriate water level of the backwash water is an amount that allows a part of the filter medium to move upward from the water surface when the upstream perforated plate is advanced and retracted, and a part of the filter medium moves upward from the water surface. The air can be sent to the backwash water, and the vibration of the backwash water can be increased by mixing the air.

  According to the present invention relating to the filtration device, the upstream perforated plate can be advanced and retracted along the support in the casing, so that the distance from the downstream perforated plate can be changed by moving the upstream perforated plate back and forth. The filter medium disposed between the two perforated plates can be expanded and contracted. Therefore, at the time of backwashing, the filter medium can be vibrated in the backwash water or near the water surface by storing the backwash water in the casing and then moving the upstream perforated plate back and forth. The filter medium can be washed only by the forward / backward operation of the plate. Therefore, it is not necessary to always pass backwash water through the casing, and backwashing can be performed by backwashing water with a small amount that can be stored in the casing. Moreover, the stored backwash water can flow back through the casing by flowing backwash water after washing the filter medium, and can be discharged from the upper part of the casing without mixing with the filtered treated water. Can be discarded. In this case, the amount of backwash water may be such that all the backwash water stored in the casing can be discharged, and the filter medium can be washed with a small amount of backwash water. Thus, the present invention can provide a filtration device that can be backwashed easily and inexpensively.

  In particular, since the upstream perforated plate and the downstream perforated plate are supported by the same column, the advance and retreat of the upstream perforated plate causes a change in the distance from the downstream perforated plate as it is. Vibrations to the filter medium disposed in the middle of the plate can be generated regularly and easily. Further, since the downstream porous plate is supported by the support column, when the downstream porous plate is moved (moved forward) in the direction of raw water flow, the moving direction is guided by the support column, and the filtration operation state It is possible to quickly move to the position of the downstream perforated plate suitable for the above.

  Further, since the backwash water is stored in the casing at the time of backwashing, that is, since the backwash water is not passed, a part of the casing (for example, raw water injection) It is also possible to open part of the side. Therefore, it is possible to transmit a driving force for moving the upstream perforated plate forward and backward using the opened portion, and it is not necessary to install a mechanism for the forward and backward driving in the casing. The upstream perforated plate can be moved back and forth using a drive device, but can also be manually performed by an operator using the opened portion. For example, in an invention including a sheath member, the advancement / retraction operation by manual operation at this time can be performed by the operator advancing / retreating the sheath member.

  On the other hand, according to the present invention relating to the backwashing method of the filter medium, the filter medium can be backwashed by forcibly moving the upstream perforated plate back and forth by a driving device or by manual operation. The filter medium can be washed with backwash water. In addition, in the case of the backwashing method of the present invention, it is only necessary to advance and retract the upstream perforated plate, so that backwashing by hand is easy, and the state of backwashed water stored (turbidity) Etc.) by visual inspection, it is possible to grasp the degree of cleaning of the filter medium.

It is explanatory drawing which shows 1st embodiment of a filtration apparatus. It is explanatory drawing which shows the detail of a support apparatus. (A) shows the state at the time of filtration operation, (b) is explanatory drawing which shows the state at the time of backwashing. It is explanatory drawing which shows the support apparatus part of 2nd embodiment of a filtration apparatus. It is explanatory drawing which shows the state at the time of backwashing of 2nd embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First embodiment of filtration device]
FIG. 1 is a diagram showing an outline of a first embodiment according to a filtration device. In the present embodiment, as shown in FIG. 1, a filter medium 2 is accommodated in a cylindrical casing 1. The casing 1 includes an inflow portion 11 for allowing the raw water to flow in and a discharge portion 12 for discharging the treated water after being filtered, and the filter medium 2 is provided between the inflow portion 11 and the discharge portion 12. The accommodating part 10 which accommodates is formed. The raw water is supplied through a pump (not shown), supplied with an appropriate pressure, and supplied from the inflow portion 11. Then, after turbidity is trapped in the filter medium 2 inside the accommodating part 10, it is discharged from the discharge part 12, and the raw water is discharged from the inflow part 11 (upper part in the figure) to the discharge part 12 (lower part in the figure). ).

  The filter medium 2 accommodated in the casing 1 is supported by a support device 3. The support device 3 includes a support column 31 and a base end side porous plate 32 that supports the base end (lower end) of the support column 31, and the base end of the support column 31 is located at the center of the base end side porous plate 32. The support 31 can be erected in the vicinity of the center of the casing 1 by being fixed and disposing the base end side porous plate 32 at a position near the discharge portion 12 in the accommodating portion 10 of the casing 1. In this state, the distal end (upper end) side of the support column 31 is the upstream side when raw water passes, and the proximal end (lower end) side is the downstream side. The support device 3 includes an upstream porous plate 33 supported near the tip end (upstream side in the water flow direction) of the support column 31 and a downstream porous plate supported near the base end (downstream side in the water flow direction). 34, and both the porous plates 33 and 34 are supported in a bowl shape with respect to the support column 31 and are spaced apart with an appropriate distance. Further, both the porous plates 33 and 34 are slidable in the axial direction of the support column 31, and a filter medium is mounted between the two porous plates 33 and 34.

  In the present embodiment, the casing 1 is formed in a cylindrical shape so that the cross section of the flow path inside the casing 1 is circular. In the housing portion 10, the large diameter portion 10a having a large flow path cross-sectional area, It is divided into a small diameter portion 10b having a small road cross-sectional area. The downstream porous plate 34 has an outer diameter that can be fitted into the small-diameter portion 10b. On the other hand, the upstream porous plate 33 can be fitted into the large-diameter portion 10a, but is fitted into the small-diameter portion 10b. It has an outer diameter that is impossible.

  The filter medium 2 is composed of a string-shaped filter medium constituting section 20 that is aggregated, and each filter medium constituting section 20 is composed of a core string 21 and a loop-like turbid trap 22 that protrudes around the core string 21. It consists of and. Synthetic resin is used for the core string 21 and the turbidity trapping material 22 constituting the filter medium constituting part 20, and an appropriate strength can be obtained by using polyester, nylon, polyvinyl chloride, polyvinylidene chloride, or the like. However, the present invention is not limited to this. In addition, as the filter medium component 20, Biocode (registered trademark) manufactured by TBI Co., Ltd. can be used.

  And the longitudinal direction of the said filter-medium component 20 is connected to the support | pillar 31 by connecting one end of the above string-like filter media components 20 to the upstream porous plate 33 and connecting the other end to the downstream porous plate 34. It is possible to mount it in a direction approximate to the axial direction of the water (flow direction of raw water). Accordingly, the individual filter medium constituting portions 20 are arranged with an appropriate interval between adjacent ones. Here, as described above, the upstream perforated plate 33 and the downstream perforated plate 34 have different outer diameters, so that the interval is large in the vicinity of the upstream perforated plate 33 and in the vicinity of the downstream perforated plate 34. It becomes small and the whole filter medium 2 is in a dense state in the direction of water flow.

  By the way, since the core string 21 of the filter medium constituting part 20 constituting the filter medium 2 is composed of the above-described synthetic resin, it has relatively flexibility, and even if the core string 21 itself does not expand and contract. By changing the distance between the upstream perforated plate 33 and the downstream perforated plate 34, the distance can be changed between a relaxed state and a tensioned state (this may be stretchable in some cases). Therefore, when the distance between the two porous plates 33 and 34 is shortened, the core string 21 is loosened, so that the turbid trap 22 is in an approached state, and conversely when the distance between the both 33 and 34 is increased. Since the core string 21 is tensed, the turbidity trapping material 22 can be in a relatively discrete state.

  Therefore, when raw water is filtered (at the time of filtration operation), the distance between the upstream perforated plate 33 and the downstream perforated plate 34 is shortened, and the turbidity trapping material 22 is brought closer to trap the turbidity. is there. At this time, by storing a part of the filter medium 2 in the small diameter portion 10b, the raw water can be reliably brought into contact with the filter medium 2 (particularly the turbidity trapping material 22). Move it. Conversely, when the filter medium 2 is washed (during backwashing), it is desirable that the interval between the filter medium components 20 (particularly the interval between the turbid traps 22) is widened. In order to move to the part 10a, both porous plates 33 and 34 are moved upstream. In the casing 1 of the present embodiment, a tapered intermediate portion 10c is formed between the large-diameter portion 10a and the small-diameter portion 10b, and a part of the filter medium 2 (on the upstream perforated plate 33) is formed during the filtration operation. Since the interval between the individual filter medium constituent parts 20 changes along the water flow direction by storing the vicinity) in the intermediate part 10c, a relatively large turbidity is captured upstream, and a fine turbidity is obtained. Can be captured downstream.

Next, details of the support device 3 will be described. FIG. 2 shows only the support device 3. As shown in this figure, the support column 31 is formed in a round bar shape, and the base end 35 is engraved with a male screw. A hub 32 a is provided in the center of the base end side porous plate 32, a female screw is engraved inside the hub 32 a, and is screwed into and supported by the male screw of the base end 35 of the column 31. It has become. A hub 33 a is also provided at the center of the upstream porous plate 33, a through hole is provided at the center, and is supported by being inserted from the tip 36 of the column 31. Further, the downstream side perforated plate 34 is similarly supported by providing a through hole in the hub 34a and inserting the support 31 into the through hole. The struts 31 are inserted through the through holes provided in the hubs 33a and 34a of the upstream perforated plate 33 and the downstream perforated plate 34 with appropriate play. It is supported in a slidable state in the axial direction. Note that a hook-shaped stopper 37 is provided at an appropriate position of the support column 31 so that sliding of the downstream porous plate 34 (or the upstream porous plate 33) is restricted.

  By the way, the base end side porous plate 32, the upstream side porous plate 33, and the downstream side porous plate 34 are each configured in a wheel shape. That is, the hubs 32a, 33a, and 34a are provided at the center, and the outer peripheral portions 32b, 33b, and 34b are connected by the connecting members 32c, 33c, and 34c. The connecting members 32c, 33c, and 34c are arranged radially from the hubs 32a, 33a, and 34a toward the outer peripheral portions 32b, 33b, and 34b, and the intermediate portions of the individual connecting members 32c, 33c, and 34c are large and gap portions are formed. It is formed and functions as the perforated plates 32, 33, 34. The perforated plates 32, 33, and 34 are not limited to this type of shape, and a plurality of holes may be formed in a circular plate member, and the hubs 32a, 33a, and 34a may be formed in the center. As long as it has a through hole having the same structure as the above, its shape is not questioned.

  Since it is the above structure, the base end side perforated plate 32 will be fixed in the base end 35 of the support | pillar 31, and the downstream side perforated plate 34 is the inner side (the base end side perforated plate 32 is fixed ( It is possible to slide between the upper side) and the stopper 37. Therefore, the base end side porous plate 32 functions as a stopper on the downstream side of the downstream side porous plate 34. Further, the upstream porous plate 33 is slidable from the tip 36 of the support 31 to the stopper 37. In reality, since the filter medium 2 is disposed between the upstream porous plate 33 and the downstream porous plate 34, the upstream porous plate 33 rarely moves to the stopper 37. Further, a cap 38 that can be attached to the tip 36 of the column 31 may be provided so that the upstream side porous plate 33 is not detached from the state in which the upstream side porous plate 33 is supported by the column 31. The cap 38 can be attached by, for example, a method in which a male screw is engraved at the tip 36 of the support column 31 and a female screw is engraved in the cap 38 to be screwed together.

  Next, the operation | movement aspect of this embodiment is demonstrated. FIG. 3A shows the state during the filtration operation, and FIG. 3B shows the state during the backwashing. Since the present embodiment is configured as described above, during the filtering operation, raw water flows from the upper injection section 11 and is filtered by allowing the raw water to pass through the housing section 10 of the casing 1. At this time, the upstream porous plate 33 and the downstream porous plate 34 move downstream (downward) along the axis of the support column 31, and most of the filter medium 2 is accommodated in the small-diameter portion 10b, and a part thereof is the intermediate portion. 10c or the large diameter portion 10a. Such movement of the upstream perforated plate 33 and the downstream perforated plate 34 is due to the lowering of their own weight and also due to the water pressure of the raw water, but it can also be moved manually before the start of the filtration operation. It is. In any of the movements, the upstream perforated plate 33 and the downstream perforated plate 34 are instructed while the column 31 is inserted through the center thereof. By moving (lowering) in the direction, the filter medium 2 can be arranged in a desired state.

  At the time of backwashing, first, all raw water is removed from the casing 1 before backwashing. The drainage at this time includes, for example, a method in which after the supply of raw water is stopped, the ventilation valve 4 provided at the upper part of the casing 1 is opened to allow outside air to flow into the casing 1. Thereafter, backwashing water is introduced from the discharge unit 12 and the backwashing water is supplied into the casing 1 until an appropriate water level is reached. Even at the time of backwashing water inflow at this time, it can be made to flow in easily by opening the vent valve 4. Then, when the backwash water flows into the desired water level, the supply of the backwash water is stopped and the backwash water is stored inside the casing 1.

The water level of the backwash water is about 70% of the large diameter portion 10a of the casing 1, as shown in FIG. 3 (b). In particular, the water surface is located within the range in which the upstream perforated plate 33 can be advanced and retracted. It is a state to do. In this state, by moving the upstream porous plate 33 back and forth, the filter medium 2 in the water is vibrated, and the upstream porous plate 33 is submerged in the water from the water surface and is removed upward from the water surface. By the advance and retreat of the upstream perforated plate 33 in the vicinity of the water surface, the water surface is greatly waved, giving water flow to the backwash water and sending air to the backwash water. It is possible to remove the quality.
[Second embodiment of filtration device]
Next, a second embodiment of the filtration device will be described. In this embodiment, the configuration of the casing 1 is the same as that of the first embodiment, and the support device 3 is changed. FIG. 4 shows the support device 3. The support device 3 of the present embodiment supports (fixes) the upstream porous plate 33 to the sheath member 5. The sheath member 5 is configured by a long cylindrical member having a bottomed cylindrical shape, and the support column 31 can be inserted therein. One end (lower end) 51 of the sheath member 5 is opened to serve as an insertion port for the support 31. Further, the other end (upper end) 52 is closed (as a bottomed portion), and the tip end 36 of the support 31 is brought into contact with the end 31 to stop the insertion.

  Therefore, by attaching the sheath member 5 to the support column 31, the sheath member 5 can advance and retreat in the axial direction of the support column 31, and the upstream supported (fixed) by the advancement and retreat of the member 5. The side porous plate 33 can also advance and retreat. Therefore, when the upstream porous plate 33 is advanced and retracted during backwashing, the upstream porous plate 33 is moved forward and backward by gripping the vicinity of the tip of the sheath member 5 and moving the sheath member 5 forward and backward. It is possible to make it. The advance / retreat operation of the sheath member 5 can be performed manually by an operator, for example, or can be performed by connecting the driving device to the upper end 52 of the sheath member 5.

In FIG. 4, the range in which the sheath member 5 can be lowered (advanced) is regulated by the closed end portion (bottomed portion) 52, but the column 31 is lifted by the downstream porous plate 34 as described above. Since the stopper 37 for restricting the (retreat) range is provided, both ends 51 and 52 of the sheath member 5 are opened, and the lowering restriction is imposed on the point where the tip of the one end ( lower end ) 51 contacts the stopper 37. It is good also as a position. In addition, when it is assumed that the sheath member 5 is advanced and retracted manually, the other end ( upper end ) 52 of the sheath member 5 can be easily gripped, or a handle can be provided.

  In the present embodiment having the above-described configuration, the upstream side porous plate 33 can be easily moved back and forth during backwashing. That is, as shown in FIG. 5, at the time of backwashing, backwashing water is supplied to the casing 1 until the water level becomes appropriate, and the upstream perforated plate 33 moves forward and backward (vibrates) in the vicinity of the water surface of the backwashing water. However, at this time, the upper end 52 of the sheath member 5 is sufficiently present on the water surface even when the upstream perforated plate 33 is immersed in the water from the water surface. Therefore, for example, when the upstream perforated plate 33 is advanced and retracted manually, the sheath member 5 can be advanced and retracted without touching the backwash water while the upper end 52 of the sheath member 5 is gripped. Further, even when the drive device is advanced and retracted, the drive transmission portion is not submerged in the backwash water.

  As the drive device for moving the sheath member 5 back and forth, a device that rotates the crankshaft by a motor and converts the rotation of the motor into a reciprocating motion, or a device that directly moves back and forth by an air cylinder can be assumed.

  The above is an embodiment showing an example of a filtration device. The embodiment relating to the backwashing method of the filter medium has already been shown in the description of the operation mode of the filter device. That is, as shown in FIG. 3B or FIG. 5, an appropriate amount of backwash water is stored inside the casing 1 and the upstream perforated plate 33 is moved back and forth (up and down). At this time, the position of the upstream perforated plate 33 changes, whereas the position of the downstream perforated plate 34 does not change greatly, or the rise (retreat) is restricted by the stopper 37, and the distance of the upstream perforated plate 33 Will be shortened. Therefore, the filter medium 2 disposed between the two porous plates 33 and 34 is tensioned or loosened in the longitudinal direction (expands and contracts), and the interval of the turbid trap 22 changes, The turbidity captured by the capturing material 33 is removed.

  The turbidity removed from the turbidity trap 22 is contained in the backwash water and discharged from the casing 1 together with the backwash water. This waste water is treated for disposal by a separate drainage route from the treated water.

  The embodiments of the present invention are as described above. However, the present invention is not limited to these embodiments, and various aspects can be adopted. For example, the casing 1 is divided into a large-diameter portion 10a, a small-diameter portion 10b, and an intermediate portion 10c. However, if the state of filtration is good, the casing 1 may be configured with the same diameter. Even in this case, backwash water is stored during backwashing, and the upstream perforated plate 33 can move back and forth near the water surface, so that the filter medium can be backwashed.

  Similarly, in the drawing showing the casing 1, there is a tapered region in the middle of the small-diameter portion 10 b and the discharge portion 12, which is a state in which the base end side porous plate 32 is installed. Therefore, it is not necessary to provide such a tapered configuration region.

DESCRIPTION OF SYMBOLS 1 Casing 2 Filter medium 3 Support apparatus 4 Ventilation valve 5 Sheath member 10 Accommodating part 10a Large diameter part 10b Small diameter part 10c Middle part 11 Inflow part 12 Discharge part 20 String-shaped filter medium constituent part 21 Core string 22 Suspended material 31 Support column 32 Base end side perforated plate 32a Base end side perforated plate hub 32b Base end side perforated plate outer peripheral portion 32c Base end side perforated plate connecting member 33 Upstream perforated plate 33a Upstream perforated plate hub 33b Outer perimeter perforated plate Portion 33c Upstream perforated plate connecting member 34 Downstream perforated plate 34a Downstream perforated plate hub 34b Downstream perforated plate outer peripheral portion 34c Downstream perforated plate connecting member 35 Base end (lower end) of strut
36 Tip (upper end) of prop
37 Stopper 51 One end (lower end) of the sheath member
52 The other end (upper end) of the sheath member

Claims (6)

In a filtration apparatus comprising a cylindrical casing capable of passing raw water and a filter medium provided inside the casing and having a turbidity trapping material protruding around the core string,
A base end-side perforated plate that can be installed in the vicinity of the downstream side opening of the casing, a support that is supported by the base end-side perforated plate, and whose shaft center is disposed along the water flow direction in the casing, and the support An upstream perforated plate that is supported in a bowl shape while being supported in a saddle shape, and is disposed between the proximal perforated plate and the upstream perforated plate, A downstream perforated plate that is supported in a bowl shape and is provided so as to be able to advance and retreat in the axial direction of the column,
One end of the core cord of the filter medium is connected to the upstream perforated plate, and the other end of the core cord is connected to the downstream perforated plate. The support column includes a sheath member that appropriately covers a range from the upstream end, the upstream porous plate is supported by the sheath member, and the upstream porous plate is advanced and retracted by sliding the sheath member in the axial direction. The filtration device according to claim 1, which is provided freely. The said downstream porous plate is provided with the through-hole which can be loosely fitted to the said support | pillar, The said support | pillar is provided with the stopper part which restrict | limits the position which this downstream porous plate can advance / retreat. Filtration device. The filtration device according to any one of claims 1 to 3, wherein the casing has a downstream channel cross-sectional area smaller than an upstream channel cross-sectional area. The casing includes an intermediate flow path having an inner surface formed in a taper shape between a downstream flow path having a small flow cross-sectional area and an upstream flow path having a large flow cross-sectional area. The filtration apparatus as described. The backwashing method of the filter medium in the filtration device according to any one of claims 1 to 5, wherein backwashing water is allowed to flow into the casing from the downstream side, and the backwashing water is appropriately at a water level. A method for backwashing a filter medium, wherein the filter medium is expanded and contracted by storing in a casing and forcibly moving the upstream perforated plate back and forth.

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