JP5964707B2 - Sand settling device - Google Patents

Description

  The present invention relates to a sand settling device for separating sand contained in raw water.

  In water treatment facilities such as sewage treatment plants and water treatment plants, raw water treatment systems for treating raw water containing sand are used. As a raw water treatment system, for example, as described in Patent Document 1, a sand raising device that pumps raw water, a sand settling device that separates sand from raw water pumped by the sand raising device, and a sand settling device. A sand transport device that transports the separated sand is known.

  Moreover, what is equipped with the function which isolate | separates while classifying the sand contained in raw | natural water using the spiral flow path formed in the spiral as a sand settling apparatus suitable for a raw water treatment system is known ( For example, see Patent Document 2). In this sand settling separator, a slit is formed on the side of the spiral channel, and a part of the sand contained in the raw water flowing through the spiral channel is dropped from the slit, so that the sand having a large particle size and the grain size are reduced. It is structured to separate into small sand.

Japanese Patent Laid-Open No. 3-146147 JP 2007-307589 A

  However, in the sand sedimentation separation apparatus using the spiral channel, for example, when raw water is flowed into the spiral channel, the sand that is desired to be transported with the water to the end of the spiral channel or the vicinity thereof is spiral flow. There was a case where it dropped from the slit in the middle of the road and sufficient separation accuracy could not be obtained.

  The main object of the present invention is to provide a technique capable of increasing the separation accuracy when separating the sand by flowing raw water containing sand through a spiral flow path.

The first aspect of the present invention is:
A spiral channel for flowing raw water including sand;
A slit formed on the side of the flow path of the spiral flow path,
A sand settling device including a separation tank that drops and separates a part of the sand contained in the raw water flowing through the spiral flow path from the slit,
By providing at least one opening for introducing the raw water in the middle of the spiral flow path, the introduction position for introducing the raw water into the spiral flow path can be changed in the length direction of the spiral flow path It is a sand settling device characterized by

The second aspect of the present invention is:
A plurality of openings formed by shifting the positions in the middle of the spiral flow path;
Among the plurality of openings, an introduction unit that is attached to a formation site of one opening and allows the raw water to be introduced into the spiral flow path;
With
The sand settling device according to the first aspect, wherein the introduction position can be changed by attaching the introduction unit to any of the plurality of openings.

The third aspect of the present invention is:
The introduction unit divides the spiral flow path in a length direction at a position where the one opening portion faces, and a partition plate in which a raw water introduction hole is formed, and the raw water supplied through the raw water supply pipe is supplied to the spiral flow. An introduction pipe connected to the raw water introduction hole of the partition plate to be introduced into the road. The sand sedimentation separation apparatus according to the second aspect, characterized in that:

  ADVANTAGE OF THE INVENTION According to this invention, the isolation | separation precision when flowing raw | natural water containing sand to a spiral flow path and isolate | separating sand can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS The structural example of the sand settling apparatus which concerns on embodiment of this invention is shown, (A) is the principal part top view in the figure, (B) is the side view. It is a top view which shows the internal structure of the separation tank with which a sand settling apparatus is equipped. It is SS sectional drawing of FIG. It is a top view which shows the upper-plate part of a separation tank. It is a figure which shows the structure of an introduction unit. It is a top view which shows the structure of a cover body. It is a top view which shows the structure of packing. It is an expanded view when a spiral flow path is straightly described.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In the embodiment of the present invention, description will be given in the following order.
1. 1. Configuration of sand settling device 2. How to use the sand settling device 3. Effects according to the embodiment Modifications etc.

<1. Configuration of sedimentation separator>
FIG. 1 shows an example of the configuration of a sand settling device according to an embodiment of the present invention, in which (A) is a plan view of the main part and (B) is a side view thereof. 2 is a plan view showing an internal structure of a separation tank provided in the sand settling device, and FIG. 3 is a cross-sectional view taken along the line SS of FIG.
The illustrated sand sedimentation separation apparatus 1 is largely configured to include a separation tank 2 and a transport device 3.

(Separation tank)
The separation tank 2 separates sand contained in raw water supplied through a raw water supply pipe (not shown). More specifically, sand contained in raw water is separated into sand having a large particle diameter and sand having a small particle diameter. To be separated (classified). The separation tank 2 is formed in a cylindrical shape as a whole. The upper part of the separation tank 2 is formed in a substantially cylindrical shape, and the lower part of the separation tank 2 is formed in a substantially conical shape. A spiral channel 4 is formed in the upper part of the separation tank 2. The spiral flow path 4 is formed in a spiral shape with the outer peripheral side being the flow path start end 4a and the center side being the flow path end 4b. A slit 5 (see FIGS. 2 and 3) is formed on the side of the spiral channel 4. The slit 5 is formed on one side (outer peripheral side) in the width direction of the spiral flow path 4.

  The spiral flow path 4 is configured using a side plate 11, a bottom plate 12, and an upper plate 13. The side plate 11, the bottom plate 12 and the upper plate 13 are each provided as a component of the separation tank 2. Among these, the side plate 11 regulates (guides) the direction in which the raw water flows when the raw water flows through the spiral flow path 4. The side plates 11 are arranged in a spiral shape in a state of being located on both sides of the spiral flow path 4 in the width direction.

  The bottom plate 12 receives the raw water on the upper surface when the raw water flows through the spiral flow path 4. The bottom plate 12 is disposed so as to have the same height from the start end 4 a to the end end 4 b of the spiral flow path 4. However, the present invention is not limited to this, and the bottom plate 12 may be arranged so as to gradually become lower from the start end 4a to the end 4b of the spiral flow path 4, or may be arranged so as to become lower from the middle. The upper surface of the bottom plate 12 is disposed in a state inclined at a predetermined angle with respect to the horizontal plane. The inclination angle of the bottom plate 12 is set to 30 °, for example. The bottom plate 12 is attached to the side surface of the side plate 11 on the inner peripheral side among the pair of side plates 11 opposed in the width direction of the spiral flow path 4. Under this attached state, the bottom plate 12 is inclined at the predetermined angle so that the inner peripheral side of the bottom plate 12 is higher than the outer peripheral side. The slit 5 is formed between the edge on the outer peripheral side of the bottom plate 12 and the side plate 11 located in the vicinity thereof. The slit 5 is formed in a spiral shape along the spiral flow path 4.

  The upper plate 13 blocks the spiral channel 4 together with the side plate 11 and the bottom plate 12 described above by closing the upper side of the spiral channel 4. The upper plate 13 is attached to the upper end portion of the side plate 11. A plurality (three in the illustrated example) of openings 15, 16, and 17 are formed in the upper plate 13. These openings 15, 16, and 17 are formed in the spiral channel 4 while being displaced from each other. Specifically, the opening 15 is provided on the downstream side of the start end 4 a of the spiral flow path 4, and the opening 17 is provided on the upstream side of the terminal end 4 b of the spiral flow path 4. The opening 15 is provided on the upstream side of the spiral flow path 4 with respect to the opening 16, and the opening 17 is provided on the downstream side of the spiral flow path 4 with respect to the opening 16. Further, in the circumferential direction with respect to the spiral center of the spiral flow path 4, the opening 15 and the opening 17 are arranged at positions that are 180 ° out of phase, and the opening 16 extends from the opening 15 to the opening 17. It arrange | positions in the intermediate position of the spiral flow path 4 to reach.

  The openings 15, 16, and 17 are each formed in the same shape and size. More specifically, the openings 15, 16, and 17 are each formed in a substantially trapezoidal shape. As shown in FIG. 4, a plurality (eight in the illustrated example) of mounting holes (screw holes) 18 are formed around the opening 15. Similarly, a plurality of mounting holes 19 are formed around the opening 16, and a plurality of mounting holes 20 are also formed around the opening 17.

  An introduction unit 21 shown in FIG. 5 or a lid body 22 shown in FIG. 6 can be attached to each opening 15, 16, and 17 of the upper plate 13. For example, when the introduction unit 21 is attached to the opening 15 of the upper plate 13, the lid body 22 is attached to each of the other openings 16 and 17. When the introduction unit 21 is attached to the opening 16 of the upper plate 13, the lid body 22 is attached to each of the other openings 15 and 17, and the introduction unit 21 is attached to the opening 17 of the upper plate 13. In this case, the lid body 22 is attached to each of the other openings 15 and 16. Moreover, when connecting the raw | natural water supply pipe mentioned later to the starting end 4a of the spiral flow path 4, the cover body 22 is mounted | worn at the opening parts 15, 16, and 17, respectively.

(Introduction unit)
First, the configuration of the introduction unit 21 will be described. 5A is a view of the introduction unit 21 as viewed from above, and FIGS. 5B and 5C are views of the introduction unit 21 as viewed from the side. In addition, the dotted line in a figure shows the part corresponding to each other.

  The introduction unit 21 can introduce raw water into the spiral flow path 4 through the opening when the introduction unit 21 is attached to any one of the plurality of openings 15, 16, and 17. Is. The user who uses the sand settling device 1 can arbitrarily select which opening is to be mounted with the introduction unit 21.

  The introduction unit 21 is configured using a partition part 23, a lid part 24, and an introduction pipe 25. The partition part 23 partitions the spiral flow path 4 in the length direction at a position where the opening part to which the introduction unit 21 is attached faces. The partition part 23 is formed in a trapezoidal shape in front view according to the cross-sectional shape of the spiral flow path 4. Moreover, the partition part 23 is formed in the flat plate shape. The lower side of the partition part 23 is inclined according to the inclination angle of the bottom plate 12 described above. A raw water introduction hole 26 is provided in the partition portion 23. The raw water introduction hole 26 is formed in a circular shape in accordance with the outer diameter of the introduction pipe 25.

  The lid 24 is arranged in a state of closing the opening at the opening where the introduction unit 21 is mounted. The lid portion 24 is formed in a flat plate shape in a direction perpendicular to the partition portion 23. The lid portion 24 is formed in a substantially trapezoidal shape in accordance with the opening shape of the opening portion to which the introduction unit 21 is attached. A plurality of mounting holes (outlet holes) 27 are formed in the peripheral portion of the lid portion 24. The mounting hole 27 is formed in the lid portion 24 in the same positional relationship as the mounting holes 18, 19, and 20 described above. The lid portion 24 is provided with a tube insertion hole 28. The tube insertion hole 28 is formed in a circular shape in accordance with the outer diameter of the introduction tube 25.

  The introduction pipe 25 introduces raw water supplied through a raw water supply pipe (not shown) into the spiral flow path 4. The introduction tube 25 is a tube having a circular cross section, and is generally formed in a substantially S shape. One end of the introduction pipe 25 is connected to the partition part 23. Under this connection state, the opening at one end of the introduction pipe 25 is arranged concentrically with the raw water introduction hole 26 of the partition part 23. The introduction tube 25 is inserted into the tube insertion hole 28 of the lid portion 24. A flange portion 29 is provided at the other end of the introduction pipe 25. A plurality (eight in the illustrated example) of connecting holes 30 are formed in the flange portion 29. A raw water supply pipe (not shown) can be connected (coupled) to the other end of the introduction pipe 25 using the coupling hole 30 of the flange portion 29. The raw water supply pipe supplies raw water (mainly a mixture of sand and water) to be treated by the sedimentation separator 1. The raw water supply pipe can be connected not only to the introduction pipe 25 of the introduction unit 21 but also to an introduction pipe (not shown) provided at the start end 4 a of the spiral flow path 4. For this reason, the location where the raw water supply pipe can be connected in the longitudinal direction of the spiral flow path 4 is the location of the start end 4a of the spiral flow path 4, the location where the opening 15 is provided, and the opening 16 are provided. There are a total of four places, that is, the places where the openings 17 are provided. Since the introduction unit 21 is unitized by the partition portion 23, the lid portion 24, and the introduction pipe 25, the attachment / detachment is facilitated, and the working time can be shortened. Moreover, since the partition part 23 is provided, a backflow is prevented and it is not necessary to install the obstruction board in the location of the start end 4a.

(Lid)
Next, the configuration of the lid 22 will be described. The lid 22 is mounted in a state where the opening is closed at a site where the opening other than the opening where the introduction unit 21 is mounted. The lid 22 is formed in a flat plate shape using a metal material such as SS400. The lid body 22 is formed in a substantially trapezoidal shape in accordance with the opening shape of the opening portion to which the lid body 22 is attached. A plurality of mounting holes (open holes) 31 are formed on the peripheral edge of the lid body 22. The mounting hole 31 is formed in the lid body 22 in the same positional relationship as the mounting holes 18, 19, 20 described above. A handle 32 is provided on the upper surface of the lid 22. The lid 22 is attached to the upper plate 13 via a packing 33 shown in FIG.

(Packing)
The packing 33 is a sealing member that exerts a sealing effect when interposed between the lid 22 and the upper plate 13. The packing 33 is made of, for example, a rubber-like elastic body such as synthetic rubber. The packing 33 is formed in a substantially trapezoidal frame shape according to the opening shape of the opening portion to which the lid body 22 is attached. The shape and size of the opening of the packing 33 are set to be the same as the shape and size of each opening 15, 16, 17. In addition, a plurality of mounting holes (open holes) 34 are formed on the peripheral edge of the packing 33. The mounting holes 34 are formed in the packing 33 in the same positional relationship as the mounting holes 18, 19, 20 described above. The packing 33 can be attached not only when the lid 22 is attached to the upper plate 13 but also when the introduction unit 21 is attached to the upper plate 13 by being interposed between the lid portion 24 and the upper plate 13. is there.

  Returning to FIGS. 1 to 3 again, the description will be continued. The separation tank 2 is supported by support legs 35. An overflow drainage 36 is provided at the center of the separation tank 2. The drainage part 36 is formed as a cylindrical space in the central part of the spiral flow path 4. The terminal end 4 b of the spiral flow path 4 is disposed so as to face the drainage part 36. The upper part of the drainage part 36 protrudes upward from the upper plate 13, and an upper lid 37 is attached to the protruding end. The upper lid 37 is attached in a state of closing the opening at the upper end of the drainage part 36.

  A drain pipe 38 is disposed in the drain part 36. The drain pipe 38 is bent in a substantially L shape. A part of the drain pipe 38 (a part arranged vertically) is arranged concentrically with the drain part 36. Further, in the drainage section 36, the upper end of the drainage pipe 38 is disposed lower than the upper plate 13. The other part (the part arranged horizontally) of the drain pipe 38 is drawn to the outside through the outer wall of the separation tank 2, and a raw water discharge pipe (not shown) can be connected (connected) to the leading end.

  The lower part of the separation tank 2 is divided into a plurality of classification chambers (not shown). When the raw water supplied through the raw water supply pipe flows into the spiral flow path 4, these classification chambers are transported together with the water that has fallen from the slit 5 along the way to the end 4 b of the spiral flow path 4. It is for collecting sand separately. As one specific example, when the sand contained in the raw water is largely divided into two according to the difference in particle size, the sand that has fallen from the slit 5 in the middle of the spiral flow path 4 and the sand 5 does not fall. What is necessary is just to make it the structure which accumulate | stores the sand conveyed to the termination | terminus 4b of the spiral flow path 4 in a separate classification chamber. In addition, when it is desired to divide the sand more finely than that, the sand falling from the slit 5 in the middle of the spiral flow path 4 may be accumulated in different classification chambers depending on the difference in the dropping position.

(Transport device)
The conveyance device 3 conveys the sand separated in the separation tank 2. The transport device 3 includes a sand transport unit 40, a sand take-out unit 41, and a drive motor 42. The sand conveyance part 40 is comprised using the screw conveyor which conveys sand by rotation of the screw which is not shown in figure. The sand transport unit 40 is installed in a state inclined at a predetermined angle with respect to the horizontal plane. The inclination angle of the sand transport unit 40 is set, for example, in a range of 30 ° or more and 40 ° or less. The lower end side of the sand transport unit 40 is connected to the lower part (classification chamber) of the separation tank 2. The sand transport unit 40 is configured to receive the sand separated by using the spiral flow path 4 in the separation tank 2 and transport the sand by the rotation of the screw. The drive motor 42 is mounted on the upper end of the sand transport unit 40. The drive motor 42 serves as a drive source for rotating the screw. In addition, the sand transport unit 40 is supported by a support column 43.

  The sand take-out unit 41 is connected to the end (upper end) of the conveyance path by the sand conveyance unit 40. The sand take-out unit 41 is for taking out the sand transported to a predetermined position by the sand transport unit 40 by dropping its own weight. The sand take-out part 41 is arranged in a state of hanging substantially vertically from the upper end of the sand transport part 40. The sand take-out part 41 is formed in a cylindrical shape having a square cross section or a circle, and a sand collection container (such as a hopper) (not shown) is installed at the lower end of the sand take-out part 41 so that sand can be collected.

  In addition, when the sand is accumulated in the separation tank 2 in a plurality of classification chambers, sand having different particle sizes can be separated by separate conveyance paths by installing the conveyance device 3 in a one-to-one correspondence with the classification chamber. Can be transported and taken out. In that case, means for conveying the sand separated in the separation tank 2 is not limited to the conveying device 3 using a screw conveyor. For example, a sand discharge pipe (not shown) may be connected to the lower part (classification chamber) of the separation tank 2 and the sand may be discharged together with water through the sand discharge pipe.

<2. How to use the sedimentation separator>
First, when using the sedimentation separator 1, for example, as shown in FIG. 1, the introduction unit 21 is attached to the opening 15 of the upper plate 13, and the lid 22 is attached to each of the other openings 16 and 17. Installing. Further, a raw water discharge pipe (not shown) is connected to the end of the drain pipe 38 connected to the drain section 36 of the separation tank 2. In addition, a sand collection container (not shown) is installed under the sand take-out portion 41 of the transport device 3.

  The partition portion 23 of the introduction unit 21 is disposed in the spiral flow path 4 so as to close the spiral flow path 4 at the site where the opening 15 is formed. Further, the lid 24 of the introduction unit 21 is attached to the upper plate 13 so as to close the opening 15. Specifically, hexagon bolts (not shown) are respectively inserted into the plurality of mounting holes 27 provided in the lid portion 24, and the male screw portions of the hexagon bolts are screwed into the mounting holes 18 of the upper plate 13. Then, the lid 24 is fixed to the upper plate 13 at the site where the opening 15 is formed by tightening with an appropriate torque. The introduction pipe 25 is attached to the partition part 23 and the lid part 24 in advance. And after attaching the partition part 23 and the cover part 24, a raw | natural water supply pipe is connected to the introduction pipe 25. FIG. Thereby, the opening at the end of the introduction pipe 25 is arranged facing the downstream side of the spiral flow path 4 through the raw water introduction hole 26 of the partition part 23.

  On the other hand, the lid 22 is attached to the upper plate 13 so as to close the opening 16. Specifically, the packing 33 is disposed on the upper surface of the upper plate 13 so as to surround the opening 16, and the lid 22 is placed thereon. A hexagonal bolt (not shown) is inserted into the mounting hole 31 provided in the lid 22 and the mounting hole 34 provided in the packing 33, and the male screw portion of the hexagonal bolt is used to attach the upper plate 13. The lid 22 is fixed to the upper plate 13 at the site where the opening 16 is formed by screwing into the hole 19 and tightening with an appropriate torque.

  Similarly, the other lid 22 is also attached to the upper plate 13 so as to close the opening 17. Specifically, the packing 33 is disposed on the upper surface of the upper plate 13 so as to surround the opening 17, and the lid 22 is placed thereon. A hexagonal bolt (not shown) is inserted into the mounting hole 31 provided in the lid 22 and the mounting hole 34 provided in the packing 33, and the male screw portion of the hexagonal bolt is used to attach the upper plate 13. The lid 22 is fixed to the upper plate 13 at the site where the opening 17 is formed by screwing into the hole 20 and tightening with a suitable torque.

  After performing the above preparatory work, supply of raw water is started to the sedimentation separator 1 through the raw water supply pipe. At this time, the raw water supplied by the raw water supply pipe is introduced into the spiral flow path 4 from the raw water introduction hole 26 of the partition part 23 through the introduction pipe 25 of the introduction unit 21. As a result, the position where the raw water is introduced into the spiral flow path 4 becomes the formation site of the opening 15 of the upper plate 13 on which the introduction unit 21 is mounted. Therefore, the effective flow path length in the spiral flow path 4 is the length from the site where the opening 15 is formed to the end 4 b of the spiral flow path 4. Incidentally, the effective flow path length of the spiral flow path 4 refers to the flow path length from the raw water introduction position to the terminal end 4b of the spiral flow path 4.

  As a second attachment mode, the introduction unit 21 is attached to the opening 16 of the upper plate 13, the raw water supply pipe is connected to the introduction pipe 25, and the lid 22 is attached to each of the other openings 15 and 17. You can also. In this case, the position where the raw water is introduced into the spiral flow path 4 is a formation site of the opening 16 of the upper plate 13 on which the introduction unit 21 is mounted. Therefore, the effective flow path length in the spiral flow path 4 is the length from the site where the opening 16 is formed to the end 4 b of the spiral flow path 4.

  Furthermore, as a third attachment mode, the introduction unit 21 is attached to the opening 17 of the upper plate 13, the raw water supply pipe is connected to the introduction pipe 25, and the lid 22 is attached to each of the other openings 15 and 16. You can also. In this case, the position where the raw water is introduced into the spiral flow path 4 is a formation site of the opening 17 of the upper plate 13 on which the introduction unit 21 is mounted. Therefore, the effective flow path length in the spiral flow path 4 is the length from the site where the opening 17 is formed to the end 4 b of the spiral flow path 4.

  As a fourth attachment mode, when the raw water supply pipe is connected to the start end 4 a of the spiral flow path 4, the position where the raw water is introduced into the spiral flow path 4 is the position of the start end 4 a of the spiral flow path 4. . Therefore, the effective flow path length in the spiral flow path 4 is the length from the start end 4a to the end end 4b of the spiral flow path 4 (that is, equivalent to the entire length of the spiral flow path 4).

<3. Effect of Embodiment>
As described above, in the sedimentation separator 1 according to the embodiment of the present invention, the effective flow path length of the spiral flow path 4 can be changed without changing the positions of the start end 4a and the end end 4b of the spiral flow path 4. It has become. For this reason, the separation accuracy when the raw water containing sand flows through the spiral flow path 4 to separate the sand can be improved. The reason will be described below.

  First, when the raw water supplied through the raw water supply pipe flows into the spiral flow path 4, the sand contained in the raw water settles faster in the water as the particle size increases. For this reason, among the sands contained in the raw water, for example, sand having a relatively large particle size, when flowing through the spiral flow path 4, is subjected to the action of gravity and the action of centrifugal force and promptly reaches the upper surface of the bottom plate 12. Reach the outer periphery. Therefore, sand having a large particle size has a high probability of falling from the slit 5 in the middle of the spiral flow path 4. On the other hand, sand having a relatively small particle size, when flowing through the spiral flow path 4, floats in the raw water and does not settle easily even when subjected to the action of gravity and centrifugal force. Is carried downstream. For this reason, the probability that the sand having a small particle size is transported together with water to the terminal end 4b of the spiral flow path 4 without falling from the slit 5 in the middle of the spiral flow path 4 is increased.

  Further, in the length direction of the spiral flow path 4, the position where sand having a large particle size falls from the slit 5 becomes upstream as the particle diameter of the sand increases. That is, the greater the particle size of the sand, the shorter the flow distance when the sand moves along the spiral flow path 4. The flow distance described here is from the position where the raw water is introduced into the spiral flow path 4 until the sand contained in the raw water falls from the slit 5 or reaches the end 4b of the spiral flow path 4. It refers to the distance that the sand moves on the spiral flow path 4.

  Here, FIG. 8 shows a developed view when the spiral flow path 4 is straightly described. In FIG. 8, when the total length of the spiral channel 4 (distance from the start end 4a to the end 4b) is Ls and raw water is introduced into the spiral channel 4 under a predetermined condition (pressure, etc.), the particle diameter The flow distance (strictly speaking, there is some variation) in which the sand of D moves on the spiral flow path 4 is Lf. Moreover, the effective flow path length of the spiral flow path 4 when the formation site of the opening 15 is the raw water introduction position is L1, and the spiral flow path when the formation site of the opening 16 is the raw water introduction position. The effective flow path length of 4 is L2, and the effective flow path length of the spiral flow path 4 when the formation site of the opening 17 is the raw water introduction position is L3. These magnitude relationships are “Ls> L1> L2> Lf> L3”.

  In such a case, the position where the sand having the particle diameter D falls varies depending on the position where the raw water is introduced into the spiral flow path 4 as follows. That is, sand having a particle size D falls from the slit 5 at the P0 position when the raw water introduction position is the starting end 4a of the spiral flow path 4, and P0 when the raw water introduction position is the formation site of the opening 15. It falls from the slit 5 at the P1 position downstream of the position. In addition, when the raw water introduction position is the site where the opening 16 is formed, the sand having the particle size D falls from the slit 5 at the P2 position downstream of the P1 position, and the raw water introduction position forms the opening 17. When it is a part, it is carried to the end 4b of the spiral flow path 4.

  Thereby, the user who uses the sand settling device 1 has a desired position range when there is sand having a particle size to be dropped from the slit 5 in a certain position range in the length direction of the spiral flow path 4. The introduction position of the raw water can be changed so as to fall from the slit 5. Specifically, for example, the raw water introduction position can be changed as follows.

  That is, when the raw water is introduced from the starting end 4a of the spiral flow path 4 and the sand to be dropped from the slit 5 in the desired position range falls in the upstream from the desired position range, the raw water is introduced. By changing the position to the formation site of the opening 15, the formation site of the opening 16, or the formation site of the opening 17, the sand can be dropped from the slit 5 within a desired position range.

  In addition, when the raw water is introduced from the starting end 4a of the spiral flow path 4 or the site where the opening 15 is formed, the sand that is desired to reach the end 4b of the spiral flow path 4 falls from the slit 5 in the middle. The sand can be made to reach the terminal end 4b of the spiral flow path 4 by changing the position of the introduction to the part where the opening 16 is formed or the part where the opening 17 is formed.

  In addition, when raw water is introduced from the opening portion of the opening 16 or the opening 17, sand having a particle size desired to be dropped from the slit 5 in the desired position range falls from the slit 5 on the downstream side of the desired position range. In that case, the sand can be dropped from the slit 5 within a desired position range by changing the introduction position of the raw water to the starting end 4a of the spiral flow path 4 or the site where the opening 15 is formed.

  Further, when raw water is introduced from the opening portion of the opening 16 or the opening 17, sand that is to be dropped from the slit 5 in the middle of the spiral flow path 4 is carried to the terminal end 4 b of the spiral flow path 4. The sand can be dropped from the slit 5 in the middle of the spiral flow path 4 by changing the introduction position of the raw water to the starting end 4 a of the spiral flow path 4 or the site where the opening 15 is formed.

  As described above, in the sand sedimentation separation apparatus 1 according to the embodiment of the present invention, the introduction position of the raw water is changed so that the sand to be separated falls from the spiral flow path 4 at the position assumed in advance. The effective flow path length can be adjusted. Therefore, it is possible to remarkably improve sand separation accuracy compared to the case where raw water is introduced from a predetermined position (starting end 4a of the spiral flow path 4).

<4. Modified example>
The technical scope of the present invention is not limited to the above-described embodiments, and includes various modifications and improvements as long as the specific effects obtained by the constituent elements of the invention and combinations thereof can be derived.

  For example, the number of openings formed in the upper plate 13 of the separation tank 2 so that the introduction position of the raw water can be changed is not limited to the above-described three, but is one, two, or four or more. Also good.

  In the embodiment described above, the bottom plate 12 is attached to the inner peripheral side plate 11 of the pair of side plates 11 facing in the width direction of the spiral flow path 4, and the outer peripheral side of the bottom plate 12 is lower than the inner peripheral side. However, the present invention is not limited to this. For example, although not shown, the bottom plate 12 is attached to the outer side plate 11 of the pair of side plates 11 facing in the width direction of the spiral flow path 4, and the outer side of the bottom plate 12 is higher than the inner side. It is good also as a structure inclined like this. When this configuration is adopted, the slit 5 is formed on the inner peripheral side of the spiral flow path 4.

  In the above embodiment, the plurality of openings 15, 16, and 17 are formed in the upper plate 13 of the separation tank 2. However, the present invention is not limited to this, and the same as the above on the outer peripheral wall of the separation tank 2 that leads to the spiral channel 4 A plurality of openings may be formed for the purpose.

DESCRIPTION OF SYMBOLS 1 ... Sand sedimentation apparatus 2 ... Separation tank 3 ... Conveyance apparatus 4 ... Spiral flow path 5 ... Slit 15, 16, 17 ... Opening part 21 ... Introduction unit 23 ... Partition part 25 ... Introduction pipe 26 ... Raw water introduction hole

Claims (3)

A spiral channel for flowing raw water including sand;
A slit formed on the side of the flow path of the spiral flow path,
A sand settling device including a separation tank that drops and separates a part of the sand contained in the raw water flowing through the spiral flow path from the slit,
By providing at least one opening for introducing the raw water in the middle of the spiral flow path, the introduction position for introducing the raw water into the spiral flow path can be changed in the length direction of the spiral flow path A sand settling device characterized by that. A plurality of openings formed by shifting the positions in the middle of the spiral flow path;
Among the plurality of openings, an introduction unit that is attached to a formation site of one opening and allows the raw water to be introduced into the spiral flow path;
With
The sand settling device according to claim 1, wherein the introduction position can be changed by mounting the introduction unit in any of the plurality of openings. The introduction unit divides the spiral flow path in a length direction at a position where the one opening portion faces, and a partition part in which a raw water introduction hole is formed, and the raw water supplied through a raw water supply pipe is supplied to the spiral flow. An introduction pipe connected to a raw water introduction hole of the partition part to be introduced into a path. The sand settling separator according to claim 2.

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