JP4397670B2 - Filtration device - Google Patents

Description

  The present invention relates to a filtration apparatus for filtering raw water introduced into a filtration tank by a filtration module made of a hollow fiber membrane or the like housed in the filtration tank.

As this type of filtration device, for example, in Patent Document 1, water to be treated (raw water) is introduced from a water intake located in the middle stage of a precipitation tank, and a hollow fiber membrane module ( A filtration module is provided and communicates with a treated water tank installed below the settling tank, and the treated water is filtered by the head difference, while turbidity in the treated water is accumulated at the bottom of the settling tank to form sludge. What was taken out from the take-out has been proposed. And in the filtration apparatus of this patent document 1, when carrying out filtration continuously, when adhesion and deposition to the hollow fiber membrane of turbidity progress and processing capacity falls, the purified water of a treated water tank To the hollow fiber membrane module, and air bubbles are applied to the hollow fiber membrane module from below by air compressor so that the suspended matter (adhered matter) attached or deposited on the surface or pores of the hollow fiber membrane module is peeled and settled. I have to.
JP-A-6-238273

  By the way, in such a filtration apparatus, when the deposits adhered to the filtration module are peeled off by the bubbles generated by the backwashing from the filtration module or the air compressor, the peeled deposits have their properties, etc. However, it does not settle immediately, but gradually settles while floating in the raw water held in the filtration tank. However, while the deposits gradually settle down in this way, some of them adhere to the filtration module again, and it is difficult to return the filtration efficiency to the level close to the original efficiency when the filtration operation is resumed. There was a risk of becoming.

  In particular, among the deposits peeled off from the filtration module, in combination with the air bubbles being applied to the filtration module, a floating soot called a scum is generated and held in the filtration tank. Some of them rise to the surface of raw water. However, for example, when the turbidity and deposits settled and deposited on the bottom of the sedimentation tank in the filtration device described in Patent Document 1 are taken out from the sludge outlet, the raw water in the filtration tank is also drawn out at the same time, so the water level is At this time, the scum that floats on the surface of the raw water adheres to the filtration module again, which may significantly impair the filtration efficiency.

  The present invention has been made under such a background, and after removing the adhering matter adhering to the filtration module in this way, it is possible to prevent the exfoliated adhering matter and scum from adhering to the filtering module as much as possible. Thus, an object of the present invention is to provide a filtration device capable of performing efficient filtration by returning the filtration efficiency to the original level as much as possible when the filtration operation is resumed.

In order to solve the above problems and achieve such an object, the present invention provides a filtration module for filtering the introduced raw water into a filtration tank into which raw water is introduced and discharged, and deposits from the filtration module. And a peeling means for peeling the plate, and a roof is provided above the filtration module in the filtration tank so as to cover the filtration module in plan view, and the roof is positioned on the opposite side of the plate-like member. The pair of side edges are formed to be bent so as to protrude upward between the pair of side edges, and the pair of side edges are positioned outside the filtration module in the plan view. The other pair of side edge portions of the plate-like member bent so as to be convex upward connecting the end portions of the side edge portions are opened in a direction in which the pair of side edge portions extend. To do

  Therefore, in the filtration device configured in this way, the upper part of the filtration module is covered in a plan view by the roof disposed on the filtration module in the filtration tank, that is, backwashing from the filtration module. Even if the deposits peeled off by bubbles applied from below the filtration module float in the raw water and settle, the deposits that settle from the top of the filtration module are blocked by this roof and outside the roof in plan view. That is, since the side of the filtration module is settled, it is possible to prevent the deposit once separated from the filtration module from adhering to the filtration module again. In particular, even if scum is generated and floated on the surface of the raw water held in the filtration tank, when the raw water is discharged from the filtration tank and the water level falls, the scum adheres to the roof top surface. Therefore, it does not adhere to the filtration module under the filter module. Therefore, when the filtration operation is resumed, the filtration efficiency of the filtration module can be restored to a level as close as possible to the original efficiency, which is efficient and economical. It is possible to promote the filtration of natural raw water.

  Further, the roof is formed into a shape in which the roof is bent so as to protrude upward between a pair of side edges located on opposite sides of the plate-like member, and the pair of side edges are viewed from above in the plan view. And the other pair of side edges of the plate-like member bent so as to be convex upward connecting the ends of the pair of side edges are the pair of side edges. By opening in the extending direction, the separated deposits floating in the raw water are guided to at least one side of the pair of side edges along the upper surface of the roof formed of a plate-like member bent upwardly in a convex manner. And is surely allowed to settle out of the filtration module. On the other hand, since the other pair of side edges of the plate-like member formed by the roof is open, for example, even when air bubbles are applied from below the filtration module as described above, the deposits are peeled off. The air bubbles from which the deposits have been peeled are discharged and floated from the other pair of side edge portions opened as shown in FIG. 4, and air does not accumulate under the roof. Since the deposits peeled off due to the bubble flow are also discharged from between the filtration module and the roof, the deposits remain between the roof immediately above the filtration module and settle down to reattach to the filtration module. Can also be prevented.

  Further, when the roof is configured by a plate-like member bent upwardly, a pair of side edge portions is provided with a hook-like portion along the side edge portions, and the hook-like portion is provided with its bottom. By providing a downcomer that opens to the outside of the filtration module and extends downward, the adhering matter guided along the upper surface of the roof and the scum adhering to the upper surface of the roof as the water level decreases when the raw water is discharged Is housed in a bowl-shaped portion provided along the pair of side edge portions of the plate-like member. Further, since these deposits and scum are discharged to the outside of the filtration module through the downcomer pipe extending downward from the bowl-shaped portion, the deposits and scum are more reliably attached to the filtration module. Can be prevented.

  By providing the roof in this way, it is possible to avoid deposits and scum that settle from the top of the filtration module as described above from re-adhering to the filtration module. Re-adhering to the filtration module to some extent when discharging the scum is unavoidable, and the scum stuck to the upper surface of the roof when the raw water is discharged may remain as it is. Therefore, in the filtration apparatus of the present invention, it is desirable to provide a module washing means for washing the filtration module and a roof washing means for washing the roof when the raw water is discharged from the filtration tank. When the raw water is again introduced into the filtration tank and the filtration operation is resumed, it is possible to return to a higher filtration efficiency. Further, the module cleaning means provided in this way is a water spray pipe disposed between the lower surface of the roof and the filtration module, or the roof cleaning means is a water spray pipe disposed above the roof. Adhesives and scum can be washed away by the washing water sprayed from the watering pipe and discharged together with the raw water, which is more efficient.

  1 to 4 show a first embodiment of the present invention. In the filtration device of this embodiment, the filtration tank 1 is constituted by a casing 2 having a bottomed cylindrical shape in which raw water W to be filtered is introduced by an introduction means such as a feed water pump (not shown). The filtration module 3 and the peeling means 4 are accommodated in 2. Here, in the present embodiment, the casing 2 is made of a metal material having high corrosion resistance such as stainless steel and has a rectangular shape in plan view, and the height thereof is longer than the length of the rectangle. The vertically elongated bottomed rectangular cylinder, that is, the bottom of the rectangular cylinder is closed, and is installed with the bottom facing downward and the height direction oriented vertically. In addition, the bottom part of the casing 2 is provided with discharge means such as a drain pipe (not shown) for discharging the raw water W held in the casing 2.

  The filtration module 3 accommodated in such a filtration tank 1 includes, for example, a stack of a plurality of elements each having a hollow fiber membrane stretched in a screen shape or a flat membrane-like separation membrane, or a tubular ceramic membrane element. In this embodiment, each filtration module 3 has a substantially horizontally long rectangular parallelepiped shape. In this embodiment, there are a plurality of (three in the figure) such filtration modules 3 having the same shape and the same size, and a pair of side surfaces extending in the longitudinal direction are horizontal, and the long side of the side surfaces is the casing 2 in plan view. The filter modules 3 are stacked in parallel so as to be parallel to the long side of the rectangle to be formed and are aligned in the vertical direction with their side surfaces facing each other, and are disposed in the casing 2. However, in FIG. 1, FIG. 4, FIG. 5 to be described below, and FIG. 12 to be described later, the plurality of filtration modules 3 are collectively shown as one rectangular parallelepiped shape.

  The plurality of filtration modules 3 stacked in this way are shown in FIG. 2 and FIG. 3 with the upper end of the uppermost filtration module 3 positioned sufficiently below the upper edge of the casing 2 as shown. Thus, the plurality of filtration modules 3 as a whole are immersed in the raw water W introduced and held in the casing 2. Further, the filtration modules 3 adjacent to each other in the vertical direction may be in close contact with each other or may be spaced at an appropriate interval. The header of each filtration module 3 is connected to a suction pump via a membrane filtration water pipe (not shown), and the filtered water filtered from the raw water W by the filtration module 3 passes through the membrane filtration water pipe by the suction pump. Discharged. In this embodiment, the rectangular parallelepiped filtration modules 3 are arranged horizontally and arranged in parallel in the vertical direction. However, for example, as shown in FIG. In addition, a plurality of rows may be arranged in parallel in the horizontal direction. Moreover, the module which bundled the hollow fiber in the vertical direction instead of the flat plate may be sufficient, and the module to install is not restrict | limited.

  On the other hand, although the said peeling means 4 is shown only in FIG. 1 and is abbreviate | omitted in another figure, the deposit | attachment is peeled from this filtration module 3 with the fluid supplied toward the filtration module 3 in the filtration tank 1 In particular, in the present embodiment, air is diffused into the casing 2 as the fluid and the bubbles are applied to the filtration module 3, thereby removing the deposits attached to the surface of the filtration module 3. Have been to. That is, the peeling means 4 has, for example, a diffuser comprising a plurality of pipes or sintered pipes as shown in FIG. 4A is configured to be connected to an air supply source such as a blower via an air supply pipe (not shown), and the raw water W is held in the casing 2, and the air supplied from the air supply source is The filter module 3 located above is cleaned by air scrubbing by air diffusion by being ejected from the air holes provided in the pipe of the air diffuser 4A or fine pores formed in the sintered tube through the air supply pipe. Then, the deposit is peeled off.

  And in the casing 2 of the filtration tank 1, the roof 5 is provided above the said filtration module 3, This roof 5 is the raw | natural water W hold | maintained in the casing 2 as shown in FIG.2 and FIG.3. The filter module 3 is provided so as to be immersed therein and covers the filtration module 3 in a plan view from above. In this embodiment, the roof 5 is a rectangular plate-like member made of a metal material such as stainless steel in this embodiment, with the gap between the pair of side edge portions 5A and 5A located on opposite sides of the plate-like member facing upward. It is made into the shape bent to the cross-section reverse U-shape so that it might become convex. Further, the pair of side edge portions 5A and 5A are positioned larger than the width of the filtration module 3 as shown in FIG. 2 so that they are positioned outside the filtration module 3 in the plan view. The length of the side edge portion 5A is also longer than the length of the filtration module 3 as shown in FIG. 3, so that the roof 5 covers the filtration module 3 in plan view as described above. Further, these side edge portions 5A and 5A are positioned substantially at the same height as or slightly below the upper end portion of the filtration module 3 in the vertical direction.

  Thus, the other pair of side edge portions 5B and 5B connecting the ends of the pair of side edge portions 5A and 5A of the plate-like member constituting the roof 5 are similar to the cross-sectional shape of the roof 5. As shown in FIG. 2, the other pair of side edges 5B and 5B of the roof 5 are bent in an inverted U shape so as to protrude upward, as shown in FIGS. Are opened in the direction in which the pair of side edge portions 5A and 5A extend (the direction orthogonal to the drawing in FIG. 2 and the left-right direction in FIG. 3). The other pair of side edge portions 5B, 5B has a bowl-shaped wall portion 5C that protrudes in an arc shape on the upper surface of the roof 5 at a portion of the inverted U-shape that is curved upward. Is provided.

  In the present embodiment, in addition to the peeling means 4 that peels and cleans the deposits from the filtration module 3 while the raw water W is held in the casing 2, the raw water W is discharged when the raw water W is discharged by the discharge means. Module cleaning means 6 for cleaning the filtration module 3 is provided. The module cleaning means 6 includes a water spray pipe 6A that is provided between the roof 5 and the filtration module 3 below the roof 5 and includes a number of nozzle holes that open downward. A plurality of (four in the figure), the lower surface of the upwardly curved portion of the inverted U-shape formed by the cross section of the roof 5 parallel to the direction in which the pair of side edge portions 5A and 5A extend. Are spaced apart from each other. And at the time of discharge | emission of the raw water W in the casing 2, ie, during discharge | emission of the raw water W, or after discharge | emission, wash water, a chemical | medical solution, etc. are supplied to these sprinkling pipes 6A, and water is sprayed toward the filtration module 3 from the said nozzle hole. Thus, the filtration module 3 is washed away.

  Furthermore, in this embodiment, the roof washing | cleaning means 7 which wash | cleans the said roof 5 at the time of discharge | emission of the raw water W from the inside of such a filtration tank 1 is also provided. In the present embodiment, the roof cleaning means 7 is also provided with a number of nozzle holes that open downward in the same manner as the module cleaning means 6, and a water spray pipe 7 </ b> A that extends parallel to the direction in which the pair of side edge portions 5 </ b> A, 5 </ b> A extends. It is constituted by. However, in this embodiment, the roof cleaning means 7 is provided with only one sprinkling pipe 7A, which is smaller than the module cleaning means 6, and such a sprinkling pipe 7A forms a cross section of the roof 5. It arrange | positions so that a space | interval may be left above the protrusion of the part curved upwards among the said inverted U-shape. And also in this roof washing | cleaning means 7, at the time of discharge | emission after discharge of the raw | natural water W in the casing 2, a cleaning water, a chemical | medical solution, etc. are supplied to this sprinkling pipe 7A, and water is sprayed to the roof 5 from the said nozzle hole. Thus, the upper surface of the roof 5 is washed away.

  In the filtration device configured as described above, the raw water W introduced by the introduction means into the casing 2 of the filtration tank 1 is filtered by the filtration module 3, so that the surface of the filtration module 3 is turbid in the raw water W. In the present embodiment, when the quality or the like adheres as a deposit and the filtration efficiency is lowered, in the present embodiment, bubbles are generated from the diffuser 4A and applied to the filtration module 3 above, and air scrubbing in FIG. As shown, the deposit R is peeled off. In this case, air or filtered water may be fed into the filtration module 3 through the membrane filtration water pipe and backwashed. At this time, the air bubbles floating while peeling the deposit R through the hollow fiber membranes of the filtration module 3 are opened on the other pair of side edge portions 5B and 5B of the roof 5 on the filtration module 3. Therefore, as shown by white arrows in FIG. 4, the water surface portion of the raw water W which is discharged from the opened pair of other side edge portions 5B and 5B and further floats and is held in the casing 2. Defoaming after reaching to.

  Thus, the deposit R thus peeled off from the filtration module 3 floats in the raw water W, for example, part of the deposit R is rolled up with the air bubbles above the roof 5 on the filtration module 3, and is discharged from the diffuser 4 </ b> A. After the aeration is finished, the one having a large specific gravity settles and accumulates on the bottom of the casing 2. At this time, in the filtration device having the above configuration, the roof 5 is disposed above the filtration module 3. 3, when the deposit R wound up on the roof 5 settles down, it is blocked by the roof 5 and may reattach to the filtration module 3. Absent. For this reason, according to the filtration device having the above configuration, even when the filtration operation is resumed after the deposit R settles, the deposit R peeled off from the filtration module 3 adheres to the filtration module 3 again and the filtration is performed. The occurrence of a situation that impairs efficiency can be suppressed.

  Moreover, in the present embodiment, the roof 5 has a shape in which the plate-like member is bent upward and the upper surface of the roof 5 has an inclined surface that descends toward the side edge portion 5A. The adhering matter R that has settled on 5 is allowed to settle on the outside of the filtration module 3 from the side edge 5A so as to be guided by the inclined surface, and is deposited on the bottom of the casing 2. In addition, in the present embodiment, the roof 5 has an inverted U-shaped cross section upward and the inclined surface is formed in a convex curved surface, so that the deposit R that has settled on the roof 5 can be more reliably detected. It can be guided to the outside of the filtration module 3. Further, since the side edge 5B of the opened roof 5 is provided with a wall 5C, the deposit R enters between the roof 5 and the filtration module 3 from the opened side and is filtered. Reattachment to the module 3 can also be avoided.

  On the other hand, in the adhering substance R peeled off from the surface of the filtration module 3 by the bubbles in this way, the bubbles are taken in and combined to generate a scum (floating lees) S, which is not settled on the surface of the raw water W. Some float and float. Further, among the peeled deposits R, those having a relatively small specific gravity settle and float in the raw water W without depositing on the bottom of the casing 2, and when the filtration operation is resumed, the filtration module 3 again. It will adhere to the surface. Therefore, after the deposit R is peeled by the peeling means 4 as described above, the deposit R and the scum S once peeled off the raw water W in the casing 23 are discharged by the discharge means as shown in FIGS. After that, new raw water W may be introduced into the casing 2 to perform the filtering operation.

  Here, in this embodiment, as shown in FIGS. 7 to 9, when the raw water W in the casing 2 is discharged from the bottom by the discharging means, the scum S that has floated on the water surface portion first as the water level of the raw water W decreases. Adheres to the upper surface of the roof 5 and a part thereof is guided to the outside of the filtration module 3 along the inclined surface formed by the upper surface, but the rest sticks to the upper surface of the roof 5 as shown in FIGS. Will remain attached. Further, when the raw water W is discharged together with the scum S guided to the outside of the filtration module 3 and the separated deposit R floating in the raw water W, and the water level is further lowered, the deposit as shown in FIG. A part of R or the like may be taken into the filtration module 3 and reattached.

  Therefore, in this embodiment, the module cleaning means 6 for cleaning the filtration module 3 and the roof cleaning means 7 for cleaning the roof 5 are provided when the raw water W is discharged from the inside of the filtration tank 1 (casing 2). Even when the scum S adheres to the upper surface of the roof 5 or the deposit R adheres again to the filtration module 3 as described above, these can be washed and washed away. That is, in the present embodiment, the roof cleaning means 7 is a watering pipe 7A disposed above the roof 5, and as shown in FIG. 10, by spraying the cleaning water from the watering pipe 7A, the roof 5 The scum S adhering to the surface can be washed away. The washed scum S is guided by the inclination of the upper surface of the roof 5 and dropped outside the filtration module 3 from the side surface portion 5A.

  The module cleaning means 6 is also a water spray pipe 6A disposed between the lower surface of the roof 5 and the filtration module 3 in this embodiment, and is cleaned from the water spray pipe 6A as shown in FIGS. By spraying water, the deposit R reattached to the surface of the filtration module 3 can be washed away and discharged together with the raw water W. In addition, instead of sprinkling the cleaning water from the sprinkling tubes 6A and 7A in this way, a chemical solution or the like may be sprinkled. Further, the cleaning by the module cleaning means 6 and the roof cleaning means 7 may be started in a state in which the filtration module 3 that is discharging the raw water W from the casing 2 is still immersed in the raw water W. FIG. It is desirable to start when the water level of the raw water W is lower than the filtration module 3 as shown in FIG. In particular, when performing chemical water sprinkling, the cleaning effect is higher when the water level is lower than the filtration module 3.

  Therefore, in the filtration device configured as described above, the roof 5 is provided above the filtration module 3 in the casing 2, and this roof 5 causes sedimentation of the deposit R after peeling by the peeling means 4. Since the adhesion of the scum S and the like to the filtration module 3 at the time of reattachment or discharge of the raw water W is suppressed, the filtration efficiency by the filtration module 3 when the filtration operation is resumed thereafter is close to the initial efficiency. Can be restored. For this reason, high filtration efficiency can be maintained over a long period of time, and it is possible to achieve an efficient and economical filtration of the raw water W.

  Further, in particular, in this embodiment, the roof 5 has a shape that is bent so as to protrude upward between a pair of side edge portions 5A and 5A located on opposite sides of the plate-like member. The side edge portions 5A, 5A are disposed outside the filtration module 3 in a plan view, so that the water level is lowered when the deposit R and the raw water W settled after peeling by the peeling means 4 are discharged. The scum S that descends as it sinks and descends from the pair of side edges 5A, 5A through the outside of the filtration module 3 so as to be guided by the inclined surface of the upper surface formed by the convex bending of the roof 5. Will be. For this reason, it is possible to prevent as much as possible such depositing matter R and scum S that have settled from re-adhering to the filtration module 3, and the filtration efficiency by the filtration module 3 at the time of resuming the filtration operation can be further ensured. It is possible to return to a level close to the standard.

  On the other hand, the other pair of side edge portions 5B and 5B bent upwardly on the plate-like member connecting the ends of the pair of side edge portions 5A and 5A of the roof 5 is the pair of sides. Since the edges 5A, 5A are open to the side of the roof 5 where the edge 5A extends, the peeling means 4 is formed by the air diffuser 4A as described above, and is attached by generating air bubbles and hitting the filtration module 3. Even in the case where the kimono R is peeled off, the air bubbles which have been peeled off the deposit R by hitting the filtration module 3 can be quickly discharged from the other pair of side edge portions 5B, 5B. Therefore, for example, such a situation that air bubbles hitting the filtration module 3 stay in the lower side of the roof 5 or the separated deposit R is left between the filtration module 3 and the roof 5. Therefore, it is possible to reliably suppress the reattachment to the filtration module 3 due to the sedimentation of the deposit R remaining in this way.

  Furthermore, the filtration device of the present embodiment is provided with the module washing means 6 for washing the filtration module 3 when the raw water W is discharged as described above. Even if the adhering matter R is left behind, and when the raw water W is discharged or the like, it settles down and reattaches to the filtration module 3 by washing the filtration module 3 with this module washing means 6. It is possible to further reliably prevent the filtration efficiency from being lost when the filtration operation is resumed. Moreover, in this embodiment, the module cleaning means 6 is constituted by a water spray pipe 6A disposed between the lower surface of the roof 5 and the filtration module 3, and the cleaning water and the chemical solution are supplied from the water spray pipe 6A. Since the deposit R is washed off and the filtration module 3 is washed by spraying water, the cleaning water and the chemical solution removed along with the deposit R can be discharged together with the raw water W, which is more efficient. .

  On the other hand, the filtration device of the present embodiment is also provided with a roof cleaning means 7 for cleaning the roof 5 when the raw water W is discharged, and the water surface is reduced as the water level of the raw water W is decreased as described above. Even if the scum S floating on the surface adheres to the upper surface of the roof 5, the roof cleaning means 7 cleans and removes the scum S, thereby newly introducing the raw water W into the casing 2 and restarting the filtering operation. It is possible to suppress a decrease in filtration efficiency. Further, since the roof cleaning means 7 is also constituted by a sprinkling pipe 7A disposed above the roof 5, the cleaning water and the chemical solution are sprinkled from the sprinkling pipe 7A to wash away the scum S and discharge it together with the raw water W. In particular, since the water spray pipe 7A is positioned at the projecting end of the roof 5 that is bent upward and convex, the water spray pipe 6A of the module cleaning means 6 is, for example, as in the present embodiment. The scum S and the like can be reliably washed away even with a small number of water spray pipes 7A, which is more efficient.

  By the way, in this embodiment, the roof 5 has an inverted U-shaped cross section as described above, and both side portions thereof extend straight downward and are substantially the same as the upper end portion of the filtration module 3 at the pair of side edge portions 5A and 5A. The height of the roof 5 is positioned below the pair of side edges 5A and 5A of the roof 5 as in the second embodiment of the present invention shown in FIGS. A flange 5D extending along the side edge 5A is provided, and a down pipe 5E is provided in the flange 5D so as to open to the bottom of the flange 5D and extend downward toward the outside of the filtration module 3. May be. Here, the roof 5 in the present embodiment has a shape in which a square plate-like member is bent between the pair of side edge portions 5A and 5A so as to form a curved line such as an arc whose cross section is convex upward. As shown in FIG. 13, the saddle-like portion 5D has a shape that is bent so that the side edge portions 5A and 5A form a curve such as a semicircular arc that is smoothly connected to the curve and protrudes downward. ing.

  The downcomer 5E is provided in each of the flanges 5D and 5D provided on the pair of side edges 5A and 5A. In this embodiment, the flange 5E is located on the diagonal of the roof 5 in a plan view. It is arrange | positioned at the edge part side of the shape parts 5D and 5D, and the position of the lower end is made into the lower side rather than the upper end part of the filtration module 3, as shown in FIG. However, the downcomer 5E may be installed anywhere on the bowl-shaped portion 5D, and the pair does not have to be installed diagonally. Furthermore, both ends of the hook-shaped part 5D are closed by a substantially semicircular wall part 5F continuous from the wall part 5C of the roof 5 outside the opening part to the wall bottom of the downcomer 5E.

  Therefore, in the filtration device according to the second embodiment configured as described above, when the deposit R on the filtration module 3 is peeled off by the peeling means 4, it is rolled up on the roof 5 and then settled on the upper surface of the roof 5. The scum S or the like that adheres to the top surface of the roof 5 and is cleaned by the roof cleaning means 7 as the water level lowers when the raw water W is discharged, and the pair of side edge portions 5A, It flows to the side of 5A and is accommodated in the bowl-shaped parts 5D and 5D, and is further settled or dropped to the bottom part in the casing 2 through the outside of the filtration module 3 from the down pipe 5E at the bottom of the bowl. For this reason, it is possible to more reliably prevent these deposits R, scum S and the like from reattaching to the filtration module 3, and the filtration efficiency of the filtration module 3 when the filtration operation is resumed is further close to the original level. It can be restored.

  In the first and second embodiments, the roof 5 has an inverted U-shaped cross section or an arc shape, and its upper surface is curved and protrudes upward. As in the third and fourth embodiments shown in FIGS. 14 and 15, respectively, the upper surface of the roof 5 may be formed as a flat inclined surface so as to protrude upward. Here, in the third embodiment shown in FIG. 14, the upper surface of the roof 5 has a gable roof shape (cross-sectional “H” shape) and protrudes upward. The water pipe 7A is disposed above the protruding end of the roof 5 at the center in the width direction of the upper surface (left and right direction in FIG. 14). Further, in the fourth embodiment shown in FIG. 15, the top surface of the roof 5 is from one side (the right side edge 5A in FIG. 15) to the other side (the left side edge in FIG. 15) of the pair of side edges 5A, 5A. The water spray pipe 7A is disposed above the protruding end of the roof 5 located on the one side edge 5A side.

  Furthermore, although the said 1st-4th embodiment demonstrated the case where the filtration tank 1 was comprised by the casing 2 formed in the bottomed cylindrical shape, raw | natural water W like the said patent document 1, for example is shown. When the filtration module and the peeling means are disposed in the settling tank or the like to be introduced, the precipitation tank itself may be used as the filtration tank 1 and a roof may be disposed above the filtration module. Moreover, the filtration tank 1 is comprised by the bottomed cylindrical casing 2 like these 1st-4th embodiment, The filtration module 3, the peeling means 4, and the roof 5 are accommodated in the inside. Even in these cases, the raw water W is not introduced into the casing 2 by introducing means such as a water supply pump as in these embodiments, but the casing 2 itself is immersed in a sedimentation tank or the like in which the raw water W is held, The raw water W in the settling tank may be introduced directly into the casing 2 by providing an inlet that can be opened and closed at the top.

1 is a perspective perspective view showing a first embodiment of the present invention. It is a longitudinal cross-sectional view orthogonal to a pair of side edge part 5A of the roof 5 in embodiment shown in FIG. It is a longitudinal cross-sectional view parallel to a pair of side edge parts 5A and 5A of the roof 5 in embodiment shown in FIG. 1 is a perspective perspective view showing a state where bubbles are lifted by the peeling means 4 in the embodiment shown in FIG. 1 (however, it is an isometric view of the filtration device shown in FIG. 1 viewed from the side; The module cleaning means 6 and the water spray pipes 6A, 7A of the roof cleaning means 7 are not shown.) It is a perspective perspective view which shows the modification of the filtration module 3 in embodiment shown in FIG. It is a longitudinal cross-sectional view which shows the state which peeled the deposit | attachment R of the filtration module 3 surface by the peeling means 4 in embodiment shown in FIG. It is a longitudinal cross-sectional view which shows the state which discharge | releases raw | natural water W, after peeling the deposit | attachment R on the surface of the filtration module 3 by the peeling means 4 in embodiment shown in FIG. It is a longitudinal cross-sectional view which shows the state which discharge | releases raw | natural water W, after peeling the deposit | attachment R on the surface of the filtration module 3 by the peeling means 4 in embodiment shown in FIG. It is a longitudinal cross-sectional view which shows the state which discharge | releases raw | natural water W, after peeling the deposit | attachment R on the surface of the filtration module 3 by the peeling means 4 in embodiment shown in FIG. It is a longitudinal cross-sectional view which shows the state which wash | cleans with the module washing | cleaning means 6 and the roof washing | cleaning means 7 in embodiment shown in FIG. It is a longitudinal cross-sectional view which shows the state which wash | cleans with the module washing | cleaning means 6 and the roof washing | cleaning means 7 in embodiment shown in FIG. It is a perspective perspective view which shows the 2nd Embodiment of this invention. It is a longitudinal cross-sectional view orthogonal to a pair of side edge parts 5A and 5A of the roof 5 in embodiment shown in FIG. It is a longitudinal cross-sectional view which shows the 3rd Embodiment of this invention. It is a longitudinal cross-sectional view which shows the 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Filtration tank 2 Casing 3 Filtration module 4 Separation means 4A Air diffuser 5 Roof 5A A pair of side edge parts 5B of the roof 5 Another pair of side edge parts 5D of the roof 5 A downcomer 5E Downcomer 6 Module cleaning means 6A Module Sprinkling pipe of cleaning means 6 7 Roof cleaning means 7A Sprinkling pipe of roof cleaning means 7 W Raw water R Deposit S Scum

Claims (6)

In the filtration tank into which raw water is introduced and discharged, a filtration module for filtering the introduced raw water and a peeling means for peeling deposits from the filtration module are provided, and above the filtration module in the filtration tank. Is provided with a roof so as to cover the filtration module in plan view, and the roof is bent so as to protrude upward between a pair of side edges located on opposite sides of the plate-like member. The pair of side edge portions are positioned outside the filtration module in the plan view, and are convex upward to connect the end portions of the pair of side edge portions. The other pair of side edge portions of the plate-like member bent in this way are opened in a direction in which the pair of side edge portions extend . The pair of side edge portions is provided with a bowl-shaped portion along the side edge portion, and the bowl-shaped portion is provided with a downcomer pipe that opens to the bottom of the bowl and extends downward toward the outside of the filtration module. The filtration apparatus according to claim 1 , wherein the filtration apparatus is provided. The filtration device according to claim 1 or 2 , further comprising a module washing means for washing the filtration module when the raw water is discharged from the filtration tank. The filtration device according to claim 3 , wherein the module cleaning means is a watering pipe disposed between a lower surface of the roof and the filtration module. The filtration apparatus according to any one of claims 1 to 4 , further comprising a roof cleaning means for cleaning the roof when the raw water is discharged from the filtration tank. 6. The filtration device according to claim 5 , wherein the roof cleaning means is a watering pipe disposed above the roof.

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