JP6325722B2 - Settling tank and inflow pipe unit - Google Patents

Description

  Embodiments of the present invention relate to a settling tank and an inflow pipe unit.

  In recent years, effective use of water resources is required due to industrial development and population growth. For that purpose, reuse of wastewater such as industrial wastewater is very important. In order to achieve these, it is necessary to purify the water, ie to separate other substances from the water.

  One method for separating minute suspended matter (ss) from a liquid is a sedimentation separation method. In order to improve the separation efficiency of suspended solids in the sedimentation separation method, it is important to generate a uniform upward flow at a low speed in a rectangular or circular sedimentation tank. Therefore, a precipitation tank of a type in which the raw water lowered from the feed well is used as an upward flow and overflows from the upper part of the precipitation tank has been developed (see Patent Document 1).

  On the other hand, in such a sedimentation tank, a mechanism for changing the raw water flowing out from the bottom of the sedimentation tank into a uniform upward flow is required. As a simple method, a structure in which a structure is installed below the feed well and the flow of water is changed is generally used (see Patent Document 2). Specifically, a plate is disposed below the feed well, and the plate causes the raw water to form a collision jet on the upper surface of the plate and flow out in the horizontal direction. Thereafter, the main flow forms an upward flow on the tank wall surface and flows out through the inclined plate.

  In this method, since the raw water outflow angle is in the horizontal direction, it is difficult to generate sludge at the bottom of the sedimentation tank, and the effect of improving the quality of the treated water is obtained, and at the same time, the raw water outflow part is set at a lower position, The effect of enabling the height to be reduced is obtained. Further, since the mainstream passes near the tank wall surface, the inclined plate installed only near the tank wall surface has a greater effect and suppresses the leakage of suspended solids.

  However, the impinging jet on the upper surface of the plate forms a local high-speed flow near the plate. As a result, there is a problem that the rising flow velocity at the tank wall surface is increased, the substantial residence time is reduced, and the quality of the treated water is deteriorated.

  Further, since the high-speed jet near the bottom of the sedimentation tank has the property of drawing in the surrounding fluid, the sludge at the bottom of the sedimentation tank is likely to be rolled up. This impinging jet velocity is determined only by the treatment flow rate and the feedwell diameter when the distance between the bottom of the feedwell and the plate is more than a certain distance, so the flow velocity is finely adjusted according to the tank diameter and treatment flow rate. It is impossible to do. In particular, in order to reduce the flow velocity, it is necessary to increase the diameter of the feed well, but this is not an effective measure because it leads to a reduction in the separation area existing outside the feed well.

Japanese Patent Laid-Open No. 10-165714 JP 2006-28159 A

  The problem to be solved by the present invention is to reduce the rising rate of raw water on the tank wall surface without causing sludge winding in the inflow pipe and the sedimentation tank having a plate below the inflow pipe, and It is to increase the quality of treated water by increasing time.

The sedimentation tank of the embodiment is disposed so as to be parallel to the wall surface of the tank body in the central part of the tank body, the inflow pipe for supplying raw water into the tank body, and the inflow A raw water distribution mechanism composed of a plurality of plates disposed below the pipe. An opening centered on the axis of the inflow pipe is formed in each of the plurality of plates, and the size of the opening gradually narrows from the upper plate toward the lower plate.
The inflow pipe unit of the embodiment includes an inflow pipe for supplying raw water into the tank body, and a raw water distribution mechanism composed of a plurality of plates disposed below the inflow pipe. An opening centering on the axis of the inflow pipe is formed, and the size of the opening is gradually narrowed from the upper plate toward the lower plate.

It is sectional drawing which shows schematic structure of the sedimentation tank in 1st Embodiment. It is an enlarged view which shows the area | region of the inflow pipe lower part vicinity of the sedimentation tank shown in FIG. It is sectional drawing which shows schematic structure of the sedimentation tank in 2nd Embodiment. It is a partially expanded view at the time of seeing the several inclination board arrange | positioned in the circulation direction of the sedimentation tank (tank body) shown in FIG. 3 from the center part in the tank body. FIG. 4 is a partially enlarged view of a plurality of inclined plates arranged in the circumferential direction of the settling tank (tank body) shown in FIG. 3 when viewed from above. It is sectional drawing which shows schematic structure of the sedimentation tank in 3rd Embodiment. It is an enlarged view which shows the area | region of the inflow pipe lower part vicinity of the sedimentation tank shown in FIG.

(First embodiment)
FIG. 1 is a cross-sectional view showing a schematic configuration of a sedimentation tank in the present embodiment, and FIG. 2 is an enlarged view showing a region in the vicinity of the lower portion of the inflow pipe of the sedimentation tank shown in FIG.

  As shown in FIG. 1, the sedimentation tank 10 of the present embodiment includes a tank body 11, an inflow pipe 12 disposed so as to be parallel to the wall surface 11 </ b> A of the tank body 11, in the central portion of the tank body 11, A raw water distribution mechanism 13 disposed below the inflow pipe 12. That is, the axis of the inflow pipe 12 is disposed so as to coincide with the axis of the tank body 11.

The outer shape of the wall surface of the tank body when the tank body 11 is viewed in plan (in the figure, when viewed from above or below the apparatus) may be circular, or a rectangular shape such as a square or a rectangle. There may be. Further, it may be a pentagon or more polygonal shape. Therefore, the three-dimensional shape of the tank body 11 is a columnar shape or a polygonal column shape.
As will be described later, since it is preferable that the raw water flows uniformly in the tank body 11 in order to allow the flocs to settle efficiently, a circular shape is a perfect circle, and a polygonal shape is a positive shape. A polygonal outer shape is more preferable.

  Moreover, it is preferable that the bottom part of a tank body is the shape where the shape bottom part center was dented so that a sediment could be settled and collect | recovered efficiently. As such a concave shape, a shape in which a conical shape or a polygonal pyramid shape is turned upside down and the center of the bottom is the apex of the cone and the lowermost portion is more preferable. And in the lowest part of the bottom part of this tank body, the discharge port 11B is provided so that sediment can be discharged | emitted out of the tank body 11. FIG.

Moreover, the magnitude | size of the tank 11 can be arbitrarily adjusted according to the quantity of the raw water which should be processed. As a magnitude | size of this tank 11, the thing whose capacity | capacitance is 20-530 m < ³ >, an internal diameter is 3-15 m, and height is 2-4 m can be illustrated, for example.

  The inflow pipe 12 is arranged in the central portion of the tank body 11 so as to be parallel to the wall surface of the tank body 11, and the raw water supplied from the inflow pipe 12 is axially below the tank body 11 from the inflow pipe 12. And is supplied into the tank body 11. That is, the inflow pipe 12 is positioned at the center of the outer shape of the tank body 11 in the outer shape of the wall surface when the tank body 11 is viewed in plan, and feeds raw water toward the bottom of the tank body 11. Provided.

  Furthermore, the inflow pipe 12 is preferably provided at a position lower than the central portion in the height direction of the tank body 11. By providing it at a position lower than the central portion, it is possible to sufficiently disperse raw water, which will be described later, and to form an upward flow after dispersion.

  Further, the diameter of the inflow pipe 12 depends on the supply amount of the raw water, and may be appropriately selected depending on the size of the tank body 11 and the like. As this diameter, for example, a pipe having an inner diameter of 0.1 to 0.4 times the inner diameter of the tank body 11 is preferable.

  A raw water supply pipe 14 for supplying raw water from the outside is connected to the inflow pipe 12, and a scraping shaft 15 is disposed at the center of the inflow pipe 12. The scraping shaft 15 is configured to rotate in a direction indicated by an arrow at an upper center portion of the tank body 11 in FIG. 1 by a drive mechanism (not shown). Further, the scraping shaft 15 is connected to a support plate 16 positioned below the scraping shaft 15, and a plurality of scraping plates 17 are suspended from the support plate 16 toward the lower side (the bottom of the tank body 11). .

  The scraping shaft 15, the support plate 16 and the scraping plate 17 constitute a scraping mechanism. As described below, the sediment after the raw water treatment is scraped to the discharge port 11 </ b> B located at the bottom center of the tank body 11. The sediment can be discharged to the outside of the tank body 11 from the discharge port 11B.

  An overflow weir 18 and a discharge pipe 19 are disposed above the tank body 11.

  The raw water distribution mechanism 13 disperses the raw water supplied from the supply pipe 12 in the horizontal direction, and is preferably configured to be evenly distributed. FIG. 2 shows an example of the raw water distribution mechanism 13. As shown in FIG. 2, the raw water distribution mechanism 13 includes a circular first plate 131, a circular second plate 132, and a circular third plate 133 having the same outer shape. The first plate 131 is formed with a first opening 131A, and the second plate 132 is formed with a second opening 132A, each of which has an annular shape. The diameter of the first opening 131A is larger than the diameter of the first opening 132A, and these openings are formed concentrically around the axis of the inflow pipe 12, that is, the scraping shaft 15.

  The outer diameters of the first plate 131, the second plate 132, and the third plate 133 are not less than the diameter of the inflow pipe 12, and are preferably 1 to 3 times the diameter of the inflow pipe 12. The diameter of the first opening 131A provided in the first plate 131 can be, for example, 0.7 to 0.8 times the diameter of the inflow pipe 12, and the first plate 131 provided in the second plate 132 has a diameter of 0.7 to 0.8. The diameter of the second opening 132 </ b> A can be 0.5 to 0.6 times the diameter of the inflow pipe 12. Therefore, the diameter of the second opening 132A is smaller than the diameter of the first opening 131A. In this way, the flow rate of the supplied raw water collides with each plate in order from the outer peripheral side by sequentially reducing the diameter of the opening from the upper plate to the lower plate. It will be. The raw water colliding with the plate is evenly distributed in the horizontal direction on the outer peripheral side. Moreover, since this dispersion | distribution is performed in steps by each plate, compared with changing the flow of raw | natural water by making it collide at once, there is little load and it can disperse | distribute efficiently.

  In the present embodiment, no opening is formed in the third plate 133, but an opening smaller than the second opening 132A can also be formed. At this time, by forming an opening in the third plate, the raw water that collided with the plate is evenly distributed in the horizontal direction on the outer peripheral side, and gradually dispersed in the horizontal direction by being performed stepwise on each plate. However, the load can be released downward when the flow rate at the time of dispersion increases, such as when the amount of treated water is large.

  The first plate 131, the second plate 132, and the third plate 133 are held and fixed so as to be in a predetermined positional relationship by a holding member (not shown). Further, the raw water distribution mechanism 13 is also important in the positional relationship with the inflow pipe 12, and is arranged and fixed so that the centers (axes) thereof coincide with each other in the vertical direction. Therefore, the raw water distribution mechanism 13 is preferably fixed to the inflow pipe 12.

  The raw water distribution mechanism 13 described above is composed of three plates. However, a larger number of plates may be provided to finely disperse the raw water step by step. At this time, the number of plates is preferably about 3 to 5.

  In addition, although it demonstrates in detail in the precipitation processing method mentioned later, raw | natural water is disperse | distributed to this horizontal direction by this raw | natural water distribution mechanism 13, and the disperse | distributed raw | natural water collides with 11 A of inner wall surfaces of a tank body, and becomes an upward flow and a downward flow Divided. Here, in the tank body 11, a region where the upward flow is generated is a sedimentation separation portion, and a region where the downward flow is generated is a sludge retention portion. The sediment separation part and the sludge retention part are divided by a horizontal plane at the position where the raw water distribution mechanism 13 is provided, and the area above the horizontal plane is the sedimentation separation part, and the area below the horizontal plane is the sludge retention part. You can also.

  The tank body 11, the inflow pipe 12, the raw water distribution mechanism 13 and the like constituting the precipitation tank 10 can be made of any material, and when handling corrosive raw water, it is made of a material such as stainless steel or plastic. It is preferable to use stainless steel particularly when strength is required.

Next, a raw water treatment method using the sedimentation tank 10 shown in FIGS. 1 and 2 will be described.
When raw water containing sedimentary suspended solids (ss) is caused to flow into the upper part of the inflow pipe 12 through the raw water supply pipe 14, the raw water descends vertically downward at a constant flow rate inside the inflow pipe 12. The raw water distribution mechanism 13 located below the inflow pipe 12 is reached.

  At this time, the raw water descending in the vicinity of the wall surface 12 </ b> A of the inflow pipe 12 first collides with the outer peripheral surface 131 </ b> B of the first plate 131 located at the uppermost stage of the raw water distribution mechanism 13, and hits the wall surface 11 </ b> A of the tank body 11. It begins to flow horizontally toward. Next, the raw water descending near the middle between the wall surface 12 </ b> A of the inflow pipe 12 and the axis of the inflow pipe 12 collides with the outer peripheral surface 132 </ b> B of the second plate 132 located in the middle stage of the raw water distribution mechanism 13. It flows out horizontally toward the wall surface 11A. Next, the raw water descending near the axis of the inflow pipe 12 collides with the main surface 133B of the third plate 133 located at the lowest stage of the raw water distribution mechanism 13 and flows out horizontally toward the wall surface of the tank body 11. To do.

  Thereafter, a portion of the raw water that has reached the wall surface 11A of the tank body 11 from the first plate 131 rises along the wall surface 11A of the tank body 11, and similarly reaches the wall surface 11A of the tank body 11 from the second plate 132. A part of the raw water that has risen also rises along the wall surface 11 </ b> A of the tank body 11. Furthermore, part of the raw water that has reached the wall surface 11 </ b> A of the tank body 11 from the third plate 133 also rises along the wall surface 11 </ b> A of the tank body 11.

  Thus, in the sedimentation tank 10 of the present embodiment, unlike the conventional case, the raw water that has descended the inflow pipe 12 collides with a plate disposed below the inflow pipe 12 at a time and flows out in the horizontal direction. Instead, it is distributed in the vertical direction by the plurality of plates 131, 132 and 133 constituting the raw water distribution mechanism 13, and flows out in the horizontal direction stepwise at different heights.

  Therefore, a local high-speed flow is not formed on the surface of each plate of the raw water distribution mechanism 13, and the increase in the rising flow velocity when the raw water rises along the wall surface 11 </ b> A of the tank body 11 is suppressed. it can. As a result, since the substantial residence time in the tank 11 of the raw water, that is, the sedimentation tank 10 can be improved, the suspended solids can be effectively separated and removed, and the quality of the treated water is deteriorated. Can be avoided.

  Moreover, since a high-speed flow is not generated in the vicinity of the raw water distribution mechanism 13 as in the prior art, it is possible to suppress the winding up of the sludge at the bottom of the tank body 11, that is, the sedimentation tank 10. Therefore, it can suppress that sludge mixes in treated water, and can promote purification of treated water.

  Furthermore, even when the lower part of the inflow pipe 12 and the raw water distribution mechanism 13 are separated from each other by a certain distance, the raw water distribution can be performed by appropriately adjusting the number and interval of the plates in the raw water distribution mechanism 13 and the size of the opening. The flow rate of the raw water distributed in the horizontal direction from the mechanism 13 and the raw water rising along the wall surface 11A of the tank body 11 can be finely adjusted. For example, the number and interval of the plates in the raw water distribution mechanism 13 are increased, and the size of the opening is gradually reduced from the upper plate toward the lower plate, and is distributed horizontally in each plate. If the amount of raw water is adjusted, the flow velocity can be finely adjusted (reduced) according to the size of the tank body 11, that is, the sedimentation tank 10, and the amount of treated water. In addition, it is preferable that the amount of raw water distributed by each plate is approximately the same.

  Therefore, unlike the prior art, since it is not necessary to increase the diameter of the inflow pipe 12 in order to reduce the flow velocity, the problem of reduction in the separation area existing outside the inflow pipe 12 can also be avoided.

  After being distributed in the horizontal direction by the plurality of plates 131, 132 and 133 constituting the raw water distribution mechanism 13, and flowing out in the horizontal direction, the raw water that has risen along the wall surface 11A of the tank body 11 is overflowed as treated water. 18 is discharged to the outside through the discharge pipe 19.

  On the other hand, the suspended matter separated and removed in the sedimentation tank 10 accumulates at, for example, the bottom of the tank body 11, that is, the bottom of the sedimentation tank 10, and the scraping shaft 15 of the scraping mechanism is rotated in the direction indicated by the arrow in the figure. As a result, the scraping plate 17 is scraped to the center of the bottom. And this settled floating substance is discharged | emitted outside from the discharge port 11B.

  By passing through the above operation, the raw water containing suspended solids supplied into the sedimentation tank 10 is settled, and only the treated water from which the suspended solids are efficiently separated and removed is discharged from the discharge pipe 19 of the sedimentation tank 10. Will be able to get from.

(Second Embodiment)
FIG. 3 is a cross-sectional view showing a schematic configuration of the sedimentation tank in the present embodiment, and FIG. 4 shows a plurality of inclined plates arranged in the circulation direction of the sedimentation tank (tank body) shown in FIG. FIG. 5 is a partially enlarged view when seen from the center, and FIG. 5 is a partially enlarged view when a plurality of inclined plates arranged in the circulation direction of the settling tank (tank body) shown in FIG. 3 is seen from above. FIG.

  In addition, the same code | symbol is used about the same or the same component as the component shown in FIG.1 and FIG.2.

  In the sedimentation tank 20 of the present embodiment, as shown in FIGS. 3 and 5, a plurality of inclined plates 25 are arranged on the wall surface 11 </ b> A of the tank body 11 in the circumferential direction with respect to the sedimentation tank 10 of the first embodiment. Different points are set. Further, an area of the inclined plate 25 that is in contact with and fixed to the wall surface 11A of the tank body 11 is disposed so as to form an angle θ with the horizontal direction.

  Therefore, as described in the first embodiment, when raw water containing sedimentary floating substances flows into the upper part of the inflow pipe 12 through the raw water supply pipe 14, the vicinity of the wall surface 12A of the inflow pipe 12 descends. The raw water that has fallen near the middle of the wall surface 12A of the inflow pipe 12 and the axis of the inflow pipe 12 and the raw water that has descended near the axis of the inflow pipe 12 are respectively The outer peripheral surface 131B of the first plate 131 located in the upper stage, the outer peripheral surface 132B of the second plate 132 located in the middle stage of the raw water distribution mechanism 13, and the third plate 133 located in the lowermost stage of the raw water distribution mechanism 13 Collides with main surface 133B. And in this embodiment, when the distributed raw water flows horizontally toward the wall surface of the tank body 11 and then rises along the wall surface 11A of the tank body 11, the raw water collides with the inclined plate 25. To come.

  Therefore, according to this embodiment, a local high-speed flow is not formed on the surface of each plate of the raw water distribution mechanism 13. Furthermore, in addition to the substantial increase in residence time due to the suppression of the increase in speed of the rising flow velocity when the raw water rises along the wall surface 11A of the tank body 11, the raw water comes to collide with the inclined plate 25. Floating substances in the raw water can be separated and removed more effectively, and the quality of the treated water can be maintained in a good state.

  In addition, angle (theta) which the area | region contacted and fixed to 11 A of wall surfaces of the tank body 11 of the inclined plate 25 shown in FIG. 4 with respect to a horizontal direction can be 45 to 80 degree | times, for example. Moreover, the width L can be 5 to 30% of the radius of the tank body 11, and the height H can be 10 to 50% of the height of the tank body 11. Furthermore, the inclined plate 25 can be in any form such as a corrugated plate member in addition to a rectangular plate member.

  Since the other characteristics and advantages in the sedimentation tank 20 of the present embodiment are the same as those of the sedimentation tank 10 of the first embodiment, description thereof is omitted.

(Third embodiment)
FIG. 6 is a cross-sectional view showing a schematic configuration of the sedimentation tank in the present embodiment, and FIG. 7 is an enlarged view showing a region in the vicinity of the lower part of the inflow pipe of the sedimentation tank shown in FIG.

  In addition, the same code | symbol is used about the same or the same component as the component shown in FIG.1 and FIG.2.

  In the sedimentation tank 30 of this embodiment, as shown in FIG.6 and FIG.7, the plate for adjusting the space | interval of the several plate which comprises the raw | natural water distribution mechanism 13 with respect to the sedimentation tank 10 of 1st Embodiment. The difference is that an interval control mechanism 35 is provided. The plate interval control mechanism 35 is a fixing jig 351 for fixing the lowermost third plate 133 disposed at the lower end of the scraping shaft 15, and an outer peripheral surface of the third plate 133. , And a pair of threaded shafts 352 disposed at opposite positions. Screw threads (not shown) are formed on the entire side surface of the threaded shaft 352 or in the vicinity of the first plate 131 and the second plate 132 where the first plate 131 and the second plate 132 are screwed. The screw holes 131C and 132C provided are meshed with each other.

  Therefore, in the present embodiment, the first plate 131 and the second plate 132 are screwed to the threaded shaft 352, and the threaded shaft 352 is rotated, so that the space between the first plate 131 and the second plate 132 is increased. The relative position, or the relative position of the first plate 131 and / or the second plate 132 with the third plate 133 can be controlled. As a result, according to the plate interval control mechanism 35 of the present embodiment, the interval between the three plates constituting the raw water distribution mechanism 13 can be adjusted.

  That is, in the sedimentation tank 30 of this embodiment, since the space | interval of the plate in the raw | natural water distribution mechanism 13 can be increased / decreased, the said flow rate is adjusted finely according to the magnitude | size of the tank body 11, ie, the sedimentation tank 10, and the amount of treated water. can do. Therefore, since the flow rate of the raw water distributed horizontally from the raw water distribution mechanism 13 and the raw water rising along the wall surface 11A of the tank body 11 can be finely adjusted, the lower part of the inflow pipe 12 and the raw water distribution mechanism 13 are constant. Even in the case of being separated as described above, it is not necessary to increase the diameter of the inflow pipe 12 in order to reduce the flow velocity, and the problem of reduction of the separation area existing outside the inflow pipe 12 can be avoided.

  Other features and advantages of the sedimentation tank 30 of the present embodiment are the same as those of the sedimentation tank 10 of the first embodiment, and thus description thereof is omitted.

  As mentioned above, although several embodiment of this invention was described, these embodiment was posted as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  10, 20, 30 Precipitation tank; 11 tank body; 11A wall surface of tank body; 11B outlet of tank body; 12 inflow pipe; 13 raw water distribution mechanism; 131 first plate; 132 second plate; 14 raw water supply pipe; 15 scraping shaft; 16 support plate; 17 scraping plate; 18 overflow weir; 19 discharge pipe; 25 inclined plate; 35 plate interval control mechanism

Claims (6)

Tank body,
An inflow pipe for supplying raw water into the tank, disposed in the center of the tank so as to be parallel to the wall of the tank;
A raw water distribution mechanism comprising a plurality of plates disposed below the inflow pipe,
All of the plurality of plates are formed with an opening centered on the axis of the inflow pipe, and the size of the opening is gradually narrowed from the upper plate toward the lower plate. And a sedimentation tank.   The settling tank according to claim 1, further comprising a plurality of inclined plates disposed in a circumferential direction of the inner wall surface of the tank body.   The settling tank according to claim 1 or 2, further comprising a plate interval control mechanism arranged to control an interval between the plurality of plates. An inflow pipe for supplying raw water into the tank,
A raw water distribution mechanism comprising a plurality of plates disposed below the inflow pipe,
All of the plurality of plates are formed with an opening centered on the axis of the inflow pipe, and the size of the opening is gradually narrowed from the upper plate toward the lower plate. Inflow pipe unit. An inflow pipe for supplying raw water into the tank,
A raw water distribution mechanism comprising a plurality of plates disposed below the inflow pipe,
Except for the plate located at the lowermost end, the plurality of plates are formed with an opening centered on the axis of the inflow pipe, and the size of the opening changes from the upper plate to the lower plate. An inflow pipe unit characterized by being narrowed sequentially as it goes.   The inflow pipe unit according to claim 4 or 5, further comprising a plate interval control mechanism arranged to control an interval between the plurality of plates.

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