JP2012179577A - Sand sedimentation basin and sand collection method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sand sedimentation basin, efficiently transferring deposited sand to a predetermined distance.SOLUTION: The sand sedimentation basin 1 includes: a groove forming wall 30 provided at the bottom of the basin to form a groove G where dropping sand is deposited; a sand collecting pit 4 provided at the bottom of the basin, to which the groove G is connected; and a discharge port unit 5 disposed in a trough 3 and having one or two or more discharge ports for discharging a fluid to the groove G from a predetermined position in the extending direction of the groove G, wherein the discharge port unit 5 discharges 1,000 to 3,000 liters of fluid per minute.

Description

  The present invention relates to a sand basin in which sand contained in received water sinks and a method for collecting the sand.

  Conventionally, a sewage treatment system accepts sewage such as sewage or rainwater, sinks the sand contained in the sewage to the bottom of the pond, and then moves the sand deposited on the pond bottom to the sand collecting pit. Some have sand ponds to be removed. Some of these sand basins include mechanical sand collecting means having a mechanical part such as a screw conveyor for collecting sand accumulated on the bottom of the pond. As a sand basin provided with a mechanical sand collecting means, for example, one described in Patent Document 1 is known. Some sand basins include sand collecting means for moving sand accumulated on the bottom of the sand basin toward a sand collecting pit by the flow of fluid discharged from a plurality of discharge ports. As a sand settling basin provided with such an outlet, what was indicated, for example in patent documents 2-4 is known.

JP 2004-160417 A JP 2001-276507 A JP 2002-159803 A Japanese Patent Laid-Open No. 9-70503

  However, in the sand basin provided with the mechanical sand collecting means shown in Patent Document 1, the machine part such as a screw conveyor operates and collects sand in the sand collecting pit. Can get into the machine part and cause troubles. Furthermore, there is a possibility that the machine part in the sewage may be corroded, resulting in a problem that the maintenance cost becomes high. A sand settling basin equipped with a sand collecting means that moves sand toward the sand collecting pit by the flow of fluid discharged from the discharge port is caused by wear of the mechanical part like a sand collecting pond equipped with a mechanical sand collecting means. There is no problem. However, the sand basin shown in Patent Document 2 discharges the fluid from the discharge port after removing the sewage in the sand basin, and can only be applied to a sand basin where an opportunity to remove the sewage from the sand basin is obtained. is there. The sand basins shown in Patent Document 3 and Patent Document 4 are intended to move sand depending on the pressure of water discharged from the discharge port. However, even if you try to move the accumulated sand depending on the pressure of the water, the sand does not move enough, or the sand accumulated on the bottom of the pond soars upward, and the sand does not move as expected. There is. The sand basin shown in Patent Document 4 is provided with a partition wall to prevent the sand from rising, but there is a possibility that the movement of the sand is hindered by the partition wall or that the sand accumulates on or in the partition wall. .

  In view of the above circumstances, an object of the present invention is to provide a sand basin that has been devised to efficiently move accumulated sand by a predetermined distance.

The sand basin of the present invention that solves the above object is a sand basin in which the sand contained in the received water sinks.
A groove-forming wall provided at the bottom of the pond and forming a groove in which the sedimented sand is deposited;
A sand collecting pit provided at the bottom of the pond and connected to the groove;
A discharge port unit that is disposed on the groove forming wall and includes one or a plurality of discharge ports that discharge fluid to the groove from a predetermined position in the extending direction of the groove;
The discharge port unit discharges 1000 liters or more and 3000 liters or less of fluid per minute.

  According to the sand basin of the present invention, fluid of 1000 liters to 3000 liters per minute is discharged from the discharge port unit, so that the accumulated sand can be efficiently moved a predetermined distance.

  Here, when the discharge unit is composed of a plurality of discharge ports, the total amount of discharge from the plurality of discharge ports per unit time is 1000 liters or more and 3000 liters or less per minute.

  A plurality of the projecting port units may be arranged on the groove forming wall with an interval in the extending direction of the groove.

In the sand basin according to the present invention, the pond bottom includes a bottom surface continuous with the groove,
It is preferable that the bottom surface is inclined downward toward the groove.

  Since the bottom surface is inclined toward the groove, the sedimented sand can be collected in the groove.

In the sand basin of the present invention, the groove forming wall has an extending portion extending toward the sand collecting pit at the wall bottom portion,
The discharge port preferably discharges fluid along the extended portion.

  By doing so, the sand can be efficiently moved along the groove.

In the sand basin of the present invention, the groove forming wall has a step-shaped wall bottom portion that gradually increases toward the sand collecting pit,
It is also preferable that the discharge port unit is arranged at a step portion connecting the upper step portion and the lower step portion in the stepped wall bottom portion.

  By disposing the discharge port unit in the stepped portion, the discharge port unit does not hinder sand movement.

In the sand basin of the present invention, the groove forming wall is at least partly composed of an inner peripheral surface of a plate-like member,
It is also one of preferred embodiments that a discharge nozzle having a part of the outer peripheral surface of the plate-like member as a part of an inner wall connected to the discharge port unit is provided.

  According to this aspect, the configuration of the discharge nozzle can be simplified, and the thickness of the discharge nozzle in the vertical direction can be suppressed.

A sand collection method for a sand basin according to the present invention is a sand collection method for collecting the sand in a sand basin in which sand contained in received water sinks,
A settling step for sinking the sand into a groove provided at the bottom of the pond;
A sand collecting step for discharging fluid from the predetermined position in the extending direction of the groove to the groove and moving the sand settling in the groove toward the sand collecting pit connected to the groove by the flow of the fluid; ,
The sand collecting step is a step of discharging fluid of 1000 to 3000 liters per minute.

  According to the sand collection method of the sand basin of the present invention, fluid of 1000 liters to 3000 liters per minute is discharged from the discharge port unit, so that the accumulated sand can be efficiently moved a predetermined distance.

  ADVANTAGE OF THE INVENTION According to this invention, the sedimentation basin which can move the deposited sand to predetermined distance efficiently, and its sand collection method can be provided.

It is the top view which looked at the sand basin equivalent to one Embodiment of this invention from upper direction. It is AA sectional drawing of the sand basin shown in FIG. (A) is the fragmentary perspective view which showed the B1 part shown in FIG. 2 in a trough, (b) is the fragmentary sectional view which expanded and showed the B1 part shown in FIG. (A) is CC sectional drawing of FIG. 2 showing a trough and a discharge nozzle, (b) is the top view which looked at (a) from the upper direction. FIG. 5 is a DD cross section of FIG. (A) is the fragmentary sectional view which expanded and showed the E section shown in FIG. 2, (b) is the fragmentary sectional view which looked at (a) from the left. It is a block diagram of the water supply equipment provided in the sand basin shown in FIG. It is a graph showing the movement distance of sand when 3000 liters per minute, 2000 liters per minute, and 1000 liters per minute of water are discharged from a discharge outlet. It is a fragmentary sectional view which shows the modification of a protrusion nozzle. It is sectional drawing which cut | disconnected the sand basin which is other embodiment of this invention in the center of the width direction. It is a block diagram of the water supply equipment provided in the sand basin shown in FIG.

  Embodiments of the present invention will be described below with reference to the drawings. A sand basin according to an embodiment of the present invention is disposed on the upstream side of a sewage treatment system, and after sedimenting sand contained in sewage or sewage such as rainwater, the sedimented sand is moved to a sand collecting pit. Remove from sewage.

  FIG. 1 is a plan view of a sand basin 1 corresponding to an embodiment of the present invention as viewed from above, and FIG. 2 is a cross-sectional view taken along line AA of the sand basin 1 shown in FIG.

As shown in FIG. 1, the sand basin 1 is a rectangular pond having a trough 3, a sand collecting pit 4, and a pump well 5 in a plan view. Hereinafter, the long side direction of the sand basin 1 may be referred to as the long side direction, and the short side direction may be referred to as the width direction. The sewage that has flowed into the sand basin 1 from a sewage pipe (not shown) slowly flows downstream in the sand basin 1. 1 and 2, the right side of the figure is the upstream side and the left side is the downstream side. The trough 3 is provided at the bottom of the sand basin 1. As will be described later, an inclined surface 6 is provided at the bottom of the pond, and a trough 3 is provided so as to be connected to the inclined surface 6. The sand in the sewage that has flowed into the sand basin 1 sinks toward the pond bottom on the upstream side of the sand basin 1 and accumulates on the pond bottom.

  The pump well 5 stores sewage from which sand has been removed. The pump well 5 is disposed on the most downstream side of the sand basin 1. In addition, as shown in FIG. 2, the bottom surface of the pump well 5 is the deepest part in the sand basin 1. A pumping pump 51 is provided in the pump well 5. The pump 51 moves sewage stored in the pump well 5 to the outside of the sand basin 1. A pumping pipe 52 is connected to the pumping pump 51. The sewage sucked by the pumping pump 51 is sent to a settling pond (not shown) through the pumping pipe 52. WL shown in FIG. 2 represents the surface of sewage. The position of the water surface WL varies depending on the amount of sewage flowing into the sand settling basin 1 such that the height from the bottom surface of the trough 3 is, for example, 1 m or more and 5 m or less.

  A sand collecting pit 4 is provided at a portion upstream of the pump well 5 at the bottom of the pond. Inside the sand collecting pit 4, a sand pump 41 is provided. The sand pump 41 is disposed in the vicinity of the bottom surface of the sand collecting pit 4, and conveys the sand collected in the sand collecting pit 4 to the outside of the sand basin 1. A sand raising pipe 42 is connected to the sand raising pump 41. The sand sucked by the sand pump 41 is sent to the outside of the sand basin 1 through the sand pipe 42.

  A trough 3 is provided at the upstream side of the sand collecting pit 4 at the bottom of the pond. As shown in FIG. 1, the trough 3 is provided at the center of the sand basin 1 in the width direction. The trough 3 includes a first U-shaped member 31, a second U-shaped member 32, a third U-shaped member 33, a first connecting member 34, and a second connecting member 35. It consists of and. The first connecting member 34 connects the first U-shaped member 31 and the second U-shaped member 32. The second connecting member 35 connects the second U-shaped member 32 and the third U-shaped member 33. In the present embodiment, the length in the longitudinal direction of each U-shaped member 31, 32, 33 is 5 m. Each U-shaped member 31, 32, 33 is formed by forming a plate material made of stainless steel having a thickness of 4 mm (corresponding to an example of a plate-shaped member in the present invention) into a U-shaped cross section.

  FIG. 3A is a partial perspective view showing the B1 portion shown in FIG. In FIG. 3A, the trough 3 is shown as being transparent. FIG. 3B is an enlarged partial cross-sectional view of the B1 portion shown in FIG.

  As shown in FIG. 3A, the first U-shaped member 31 and the second U-shaped member 32 are composed of a semi-cylindrical portion serving as a lower portion and two plane portions serving as an upper portion. It is configured. The first U-shaped member 31 and the second U-shaped member 32 differ in the inner diameter of the semi-cylindrical portion and the interval in the width direction of the plane portion. In the present embodiment, the inner diameter of the semicylindrical portion of the first U-shaped member 31 and the interval in the width direction of the planar portion are each 300 mm, and the inner diameter of the semicylindrical portion of the second U-shaped member 32 and The interval in the width direction of the planar portion is 350 mm. The first connecting member 34 is obtained by punching a stainless steel plate having a thickness of 4 mm. The first U-shaped member 31 and the first connecting member 34 are joined by welding, and the second U-shaped member 32 and the first connecting member 34 are also joined by welding.

  The third U-shaped member 33 and the second connecting member 35 shown in FIGS. 1 and 2 are also formed of a stainless steel plate material having a plate thickness of 4 mm. The inner diameter of the semi-cylindrical portion of the third U-shaped member 33 and the interval in the width direction of the plane portion are each 400 mm. The B2 portion shown in FIG. 2 has the same shape and configuration except that it is different in size from the B1 portion.

  The inner peripheral surface 310 of the first U-shaped member 31, the inner peripheral surface 320 of the second U-shaped member 32, the inner peripheral surface (not shown) of the third U-shaped member 33, and the first connecting member The groove forming wall 30 is formed by the downstream side surface 340 of 34, the downstream side surface (not shown) of the second U-shaped member 32, and the downstream side surface 360 of the end surface wall 36 (see FIG. 6A) described later. . A groove G extending in the longitudinal direction from the most upstream end of the sand basin 1 to the sand collecting pit 4 is formed by the groove forming wall 30. The most downstream end of the groove forming wall 30 is open on the sand collecting pit 4 side, and the most downstream end of the groove G is connected to the sand collecting pit 4.

As shown in FIG. 3B, the wall bottom portion 300 of the groove forming wall 30 has a stepped shape that gradually increases toward the sand collecting pit 4 on the downstream side. In FIG. 3B as well, the right side of the figure is the upstream side and the left side is the downstream side. The wall bottom portion 300 includes a first extending portion 301 serving as an upper step portion of a staircase shape, a second extending portion 302 serving as a lower step portion of the staircase shape, and a step connecting the upper step portion and the lower step portion of the staircase shape. Part 303. The first extension part 301 and the second extension part 302 extend in the longitudinal direction. In the present embodiment, the first extending portion 301 and the second extending portion 302 extend horizontally toward the sand collecting pit 4, but are inclined downward toward the sand collecting pit 4. It may be a thing. The step portion 303 is a portion that is perpendicular to the first extension portion 301 and the second extension portion 302. The step portion 303 is provided with a first discharge port 71 for discharging water. The first discharge port 71 in the present embodiment corresponds to an example of the discharge port unit of the present invention. By providing the first discharge port 71 in the stepped portion 303, when the water is discharged from the upstream discharge port (second discharge port 72 described later) to move the sand in the groove G, the first discharge port 71 is provided. It is possible to prevent the outlet 71 from hindering the movement of sand. Note that the discharge port areas of the first discharge port 71 and the second discharge port 72 in this embodiment are both 2037 mm ² . On the upstream side of the first discharge port 71, a discharge nozzle 7 that forms an empty space 75 connected to the first discharge port 71 is provided. The discharge nozzle 7 is fixed to the lower part of the first U-shaped member 31. A part of the outer peripheral surface 311 of the first U-shaped member 31 is a part of the inner wall of the discharge nozzle 7. By doing so, the configuration of the discharge nozzle 7 can be simplified, and the thickness of the discharge nozzle 7 in the vertical direction can be reduced.

  4A is a cross-sectional view taken along the line CC of FIG. 2 showing the trough 3 and the discharge nozzle 7. FIG. 4B is a plan view of FIG. 4A viewed from above. In FIGS. 4A and 4B, the plate thicknesses of the trough 3 and the discharge nozzle 7 are exaggerated.

  As shown in FIG. 4A, the discharge nozzle 7 includes a fluid receiving port 76 that protrudes in the width direction from the first U-shaped member 31. A first water supply pipe 21 (see FIG. 7) for supplying water is connected to the fluid receiving port 76. As shown in FIG. 4B, the vacant space 75 has an L shape in plan view. The water flowing into the vacant chamber 75 from the fluid receiving port 76 changes in the direction of flow to the downstream side in the vacant chamber 75 and becomes parallel to the second extending portion 302, and along the second extending portion 302. It is discharged from the first discharge port 71. By discharging water along the second extending portion 302, the sand accumulated in the groove G can be efficiently moved along the groove G.

  FIG. 5 is a DD cross section of FIG. In FIG. 5, the background is omitted.

  As shown in FIG. 5, inclined surfaces 6 are provided on both sides of the trough 3 in the width direction. The inclined surface 6 is inclined downward by 45 degrees toward the trough 3, and extends in the longitudinal direction between the uppermost stream end portion of the sand settling basin 1 and the upstream end portion of the sand collecting pit 4. The sand contained in the sewage flowing into the sand basin 1 sinks to the bottom of the pond in a process in which the sewage flows downstream. The sand that has settled on the inclined surface 6 further sinks toward the trough 3 along the inclined surface 6, so that the settled sand can be collected in the groove G. In addition, the inclination angle of the pond bottom may be, for example, 30 degrees or 60 degrees.

  FIG. 6A is a partial cross-sectional view showing the E portion shown in FIG. 2 in an enlarged manner, and FIG. 6B is a partial cross-sectional view of FIG. 6A viewed from the left.

  As shown in FIG. 6A, a plate-like end face wall 36 is attached to the end face that is the most upstream end of the first U-shaped member 31. As described above, the downstream side surface 360 of the end wall 36 forms a part of the groove forming wall 30. As shown in FIG. 6B, the end face wall 36 is provided with a second discharge port 72. The second discharge port 72 in the present embodiment also corresponds to an example of the discharge port unit of the present invention. On the upstream side of the second discharge port 72, an L-shaped pipe 77 that forms an empty chamber 78 connected to the discharge port 72 is provided. The L-shaped pipe 77 is an L-shaped pipe in plan view, and is connected to a second water supply pipe 22 (see FIG. 7) that supplies water. The water flowing into the vacant chamber 78 changes its flow direction to the downstream side in the vacant chamber 78 and becomes parallel to the first extending portion 301, and enters the first extending portion 301 from the second discharge port 72. Is discharged along. By discharging water along the first extending portion 301, the sand accumulated in the groove G can be efficiently moved along the groove G.

  FIG. 7 is a block diagram of the water supply equipment provided in the sand basin 1 shown in FIG.

The settling basin 1 is provided with a water supply pump P. This water supply pump P is a pump that supplies 2000 liters of water per minute. A branch pipe 24 is provided between each water supply pipe 21, 22, 23 connected to each discharge port 71, 72, 73 and the water supply pump P. In FIG. 7,
The 3rd discharge port 73 and the 3rd water supply pipe | tube 23 which were provided in B2 part of FIG. 2 are shown. In addition, the water supply pipes 21, 22, and 23 are provided with motorized valves V1, V2, and V3, respectively.

  Next, the effect | action of the sand settling basin 1 in this embodiment is demonstrated. First, sewage flows into the sand basin 1. The sand contained in the sewage flowing into the sand basin 1 sinks to the bottom of the basin 1 while the sewage flows through the portion where the trough 3 existing on the upstream side extends. As described above, in this part, the sand that has settled on the inclined surface 6 also sinks toward the trough 3 along the inclined surface 6, so that the settled sand gathers in the groove G and accumulates in the groove G. Next, the water supply pump P is driven and the motor-operated valve V2 is opened. At this time, the motor-operated valves V1 and V3 are closed. The water of 2000 liters per minute supplied by the water supply pump P is discharged from the second discharge port 72 via the branch pipe 24 and the second water supply pipe 22. By continuing this discharge for 5 minutes, the sand in the groove G formed by the inner peripheral surface 310 of the first U-shaped member 31 is formed by the inner peripheral surface of the second U-shaped member 32. Move to groove G. According to the inventor's research, when 2000 liters of water is discharged for 5 minutes, the sand that has settled in the groove G moves from the discharge port to 10 m ahead. FIG. 8 shows the result of an experiment conducted by the inventor. FIG. 8 shows a U-shaped member using a U-shaped member having the same shape as the first U-shaped member 31 in a sand basin in which sewage is put until the bottom of the inner peripheral surface of the U-shaped member reaches a position of 2 m. Sand when sand is further deposited from the upper part of the U-shaped member to about 100 mm, and water is discharged at 3000 liters per minute, 2000 liters per minute, and 1000 liters per minute at a discharge flow rate of 16 m / sec. It is a graph showing the movement distance of. The horizontal axis in the graph of FIG. 8 is the time (seconds) at which water is discharged from the discharge port, and the vertical axis in the graph of FIG. 8 is the sand movement distance (cm).

  From the curve shown in the graph of FIG. 8, even if the discharge time is increased unnecessarily, the sand cannot be moved efficiently, and the sand can be moved efficiently because the water discharge time is about 5 minutes. It turns out that this is the case. Also, when the water discharge time is 5 minutes, when 1000 liters of water is discharged, the sand travel distance is just over 5 m. At 2000 liters per minute, the sand travel distance is about 10 m, 3000 per minute. It can be seen that the distance traveled by sand is about 15 m.

  When water is continuously discharged from the second discharge port 72 for 5 minutes, the motor-operated valve V2 is closed and the motor-operated valve V1 is opened. Thus, 2000 liters of water supplied by the water supply pump P is discharged from the first discharge port 71. By continuing this discharge for 5 minutes, the sand in the groove G formed by the inner peripheral surface 320 of the second U-shaped member 32 is formed by the inner peripheral surface of the third U-shaped member 33. Move to groove G. Thereafter, the motor-operated valve V1 is closed and the motor-operated valve V3 is opened. Thus, 2000 liters of water supplied by the water supply pump P is discharged from the third discharge port 73. By continuing this discharge for 5 minutes, the sand in the groove G formed by the inner peripheral surface of the third U-shaped member 32 moves to the sand collecting pit 4. Finally, the water supply pump P is stopped, the motor-operated valve V3 is closed, the sand pump 41 is driven, and the sand moved to the sand collecting pit 4 is conveyed to the outside of the sand basin 1.

  In this embodiment, it is assumed that it is most effective to control the discharge flow rate from each discharge port in order to efficiently move the accumulated sand by a predetermined distance. The discharge flow rate of water at the outlets 71, 72, 73 is not limited, and the discharge flow rate is preferably 8 m / sec or more and 24 m / sec or less. If it is less than 8 m / sec, the flow velocity will be insufficient, and the sand may not be moved a predetermined distance in relation to the water pressure. If the sand cannot be moved by a predetermined distance, a large number of discharge ports are required in the sand moving direction, and the number of pipes to the discharge port increases, which makes the apparatus complicated and uneconomical. When the speed is faster than 24 m / sec, part of the sand accumulated in the groove G may rise upward, and the part of the sand may not move as expected. Furthermore, when sewage is used as sand collection water, there is a risk that the pipes will have a small diameter and clog the dust. Moreover, it is preferable that the discharge pressure of water in each discharge port 71, 72, 73 shall be 0.1 MPa or more and 0.3 MPa or less. If it is less than 0.1 MPa, water may not be discharged from the discharge port due to water pressure applied to the discharge port and pressure loss at the discharge nozzle. If it is greater than 0.3 MPa, part of the sand accumulated in the groove G will rise upward, and part of the sand may not move as expected.

  As described above, according to the sand basin 1 of the present embodiment, the discharge ports 71, 72, 73 are arranged at intervals in the extending direction (longitudinal direction) of the groove G, and the discharge ports 71, Since water of 2000 liters per minute is sequentially discharged from the grooves 72 and 73 to the groove G, the sand accumulated in the groove G can be efficiently moved a predetermined distance.

  The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope described in the claims. In the following description, it demonstrates centering on difference with the sand basin 1 demonstrated so far. In addition, the same components as those described so far are denoted by the same reference numerals as those used so far, and description thereof is omitted.

  FIG. 9 is a partial cross-sectional view showing a modified example of the discharge nozzle 7.

  In this modification, a discharge pipe 79 is provided at the tip of the discharge nozzle 7 so as to protrude from the step portion 303 toward the groove G. A discharge port 74 for discharging water is provided at the downstream end of the discharge pipe 79. In this modification, the outer shape portion of the discharge pipe 79 protruding into the groove G becomes a part of the groove forming wall 30. In addition, in this modified example, when sand accumulates just under the part which protrudes in the groove | channel G of the discharge pipe 79, there exists a fault that the sand becomes difficult to move.

  In the above-described embodiment, an example in which one discharge port 71, 72, 73 is provided for each predetermined position (5 m interval) in the extending direction of the groove G has been described. A plurality of discharge ports may be provided for each predetermined position. When a plurality of discharge ports are provided for each predetermined position, the total amount of water discharged from the plurality of discharge ports provided for each predetermined position is 2000 liters per minute. In the present embodiment, an example in which only one trough 3 is provided has been described, but a plurality of troughs 3 may be provided in parallel. In the present embodiment, the U-shaped members 31, 32, 33 are formed in a U shape in a sectional view, but may be formed in a semicircular shape, a rectangular shape with an upper opening, It is good also as a semi-oval tube shape where a curvature radius becomes small toward the side. In the case of a semi-oval tube shape, there is an effect that even if a heavy object such as a stone settles on the bottom of the pipe, the heavy object can be easily moved by the flow of water.

  Further, the water discharged from each of the discharge ports 71, 72, 73 need not be 2000 liters per minute as long as it is 1000 liters to 3000 liters per minute. In the case of less than 1000 liters per minute, the sand accumulated in the groove G may hardly move. If it exceeds 3000 liters per minute, the sand accumulated in the groove G may soar upward and the sand may not move as expected. This will be explained in more detail. In the present embodiment, it is assumed that it is most effective to control the discharge flow rate from each discharge port in order to efficiently move the accumulated sand by a predetermined distance. If the discharge flow rate is set to 16 m / sec and the discharge flow rate is reduced to 800 liters per minute, the sand will not move for a predetermined distance, and the discharge port and the pipe connected to the discharge port will have a small diameter. When sewage is used as water, there is a risk of clogging. Furthermore, since the sand does not move for a predetermined distance, a large number of discharge ports are required in the direction of sand movement, and the number of pipes to the discharge port increases, which makes the apparatus complicated and uneconomical. On the other hand, when the discharge flow rate is set to 16 m / sec, when the discharge flow rate is increased to 3200 liters per minute, a part of the sand accumulated in the groove G rises upward, and the part of the sand moves as expected. May not

  Alternatively, three pumps P may be provided, and each pump P may be connected to each discharge port 71, 72, 73, and water may be supplied from each pump P simultaneously. By simultaneously supplying from each pump P, the sand moving time can be shortened. In addition, as shown in FIG. 8, if the quantity of the water discharged from each discharge port is in the range of 1000 liters or more and 3000 liters or less per minute, a larger one can increase the sand movement distance. However, when renovating an existing sand basin and installing a discharge port, the amount of water discharged from the discharge port at the same time is less than the pumping amount of the pump 51 so that the water level of the sand basin will not rise. It is preferable. In other words, it is preferable that the pump is provided with a pump for pumping up the total amount of water discharged from the discharge port per unit time per unit time.

  Subsequently, another embodiment will be described. In the description of each of the other embodiments, the difference from the sand basin 1 described so far will be mainly described. In addition, the same components as those described so far are denoted by the same reference numerals as those used so far, and description thereof is omitted.

  FIG. 10 is a cross-sectional view of a sand basin 10 according to another embodiment of the present invention cut at the center in the width direction.

  The sand basin 10 of this other embodiment differs from the sand basin 1 of the previous embodiment in the position where the sand collecting pits 4 are provided. The sand basin 10 has an upstream trough 8 on the upstream side of the sand collecting pit 4 and a downstream trough 9 on the downstream side of the sand collecting pit 4. Further, unlike the previous embodiment, the upstream trough 8 and the downstream trough 9 have no connection member and are formed by a single U-shaped member. The upstream trough 8 and the downstream trough 9 are each formed by forming a stainless steel plate material having a plate thickness of 4 mm into a U-shaped cross section. In this other embodiment, the length of the upstream trough 8 in the longitudinal direction is 7 m, and the length of the downstream trough 9 in the longitudinal direction is 8 m.

  10 are the same as those shown in FIGS. 6A and 6B used in the description of the previous embodiment, and are attached to the upstream trough 8. An upstream discharge port 81 (see FIG. 11) is provided on the downstream side surface of the end wall, and a downstream discharge port 91 (see FIG. 11) is provided on the upstream side surface of the end wall attached to the downstream trough 9. Yes. In this other embodiment, the upstream groove forming wall 80 is formed by the inner peripheral surface of the upstream trough 8 and the downstream side surface of the end wall attached to the upstream trough 8. An upstream groove G is formed by the upstream groove forming wall 80. The most downstream end of the upstream groove G is connected to the sand collecting pit 4. Further, a downstream groove forming wall 90 is formed by the inner peripheral surface of the downstream trough 9 and the upstream side surface of the end surface wall attached to the downstream trough 9. A downstream groove G is formed by the downstream groove forming wall 90. The most upstream end of the downstream groove G is connected to the sand collecting pit 4.

  FIG. 11 is a block diagram of a water supply facility provided in the sand settling basin 10 shown in FIG.

  The sand basin 10 is provided with a water supply pump P. This water supply pump P is a pump that supplies 2000 liters of water per minute. A branch pipe 27 is provided between the water supply pipes 25 and 26 connected to the discharge ports 81 and 91 and the water supply pump P. In addition, the water supply pipes 25 and 26 are provided with motorized valves V4 and V5, respectively.

  Next, the effect | action of the sand basin 10 in this embodiment is demonstrated. First, sewage flows into the sand basin 10. While the sewage flows through the portion where the upstream trough 8, the downstream trough 9 and the sand collecting pit 4 are present, the sand contained in the sewage flowing into the sand basin 1 sinks to the pond bottom of the sand basin 1. Go. In this portion, the sand that has settled on the inclined surface 6 also sinks toward the upstream trough 8 or the downstream trough 9 along the inclined surface 6. Next, the water supply pump P is driven and the electric valve V4 is opened. At this time, the motor-operated valve V5 is closed. The water of 2000 liters per minute supplied by the water supply pump P is discharged from the upstream discharge port 81 via the branch pipe 27 and the water supply pipe 25. By continuing this discharge for 5 minutes, the sand in the upstream groove G moves to the sand collecting pit 4. Next, the motor-operated valve V4 is closed and the motor-operated valve V5 is opened. Thus, 2000 liters of water supplied by the water supply pump P is discharged from the downstream discharge port 91. By continuing this discharge for 5 minutes, the sand in the downstream groove G moves to the sand collecting pit 4. Finally, the water supply pump P is stopped, the electric valve V5 is closed, the sand pump 41 is driven, and the sand moved to the sand collecting pit 4 is conveyed to the outside of the sand basin 1. The above operation is repeated every predetermined time.

  As described above, according to the sand basin 10 of the other embodiment, the upstream discharge port 81 is arranged at the upstream end of the upstream groove forming wall 80 and the downstream end of the downstream groove forming wall 90 is downstream. Since the side discharge ports 91 are arranged and 2000 liters of water per minute is discharged from each discharge port toward the upstream groove G and the downstream groove G, the sand accumulated in the grooves is efficiently predetermined. It can be moved a distance. Further, in the sand basin 10, by providing the grooves G on the upstream side of the sand collecting pit 4 and the downstream side of the sand collecting pit 4, the length in the extending direction of the groove G becomes short. By shortening the length of the groove G in the extending direction, the discharge port can be omitted in the middle of the groove G, and the structure of the upstream trough 8 and the downstream trough 9 can be simplified.

  In addition, even if it is a structural requirement contained only in each description of each embodiment and modification which were demonstrated above, you may apply the structural requirement to another embodiment and modification.

DESCRIPTION OF SYMBOLS 1 Settling basin 30 Groove formation wall 300 Wall bottom part 301 1st extension part 302 2nd extension part 303 Step part 4 Sand collection pit 6 Pond bottom 7 Discharge nozzle 71 1st discharge port 72 2nd discharge port 73 Third outlet G Groove

Claims (6)

In the sand basin where the sand contained in the received water sinks,
A groove-forming wall provided at the bottom of the pond and forming a groove in which the sedimented sand is deposited;
A sand collecting pit provided at the bottom of the pond and connected to the groove;
A discharge port unit that is disposed on the groove forming wall and includes one or a plurality of discharge ports that discharge fluid to the groove from a predetermined position in the extending direction of the groove;
The discharge port unit discharges a fluid of 1000 liters to 3000 liters per minute. The pond bottom includes a bottom surface continuous with the groove,
2. The sand basin according to claim 1, wherein the bottom surface is inclined downward toward the groove. The groove forming wall has an extending portion extending toward the sand collecting pit at a wall bottom portion,
The sand discharge basin according to claim 1 or 2, wherein the discharge port discharges fluid along the extending portion. The groove forming wall has a step-shaped wall bottom portion that gradually increases toward the sand collecting pit,
4. The sand basin according to claim 1, wherein the discharge port unit is arranged at a stepped portion connecting an upper step portion and a lower step portion in a stepped wall bottom portion. The groove forming wall is at least partly composed of an inner peripheral surface of a plate-shaped member,
The sand basin according to claim 4, further comprising a discharge nozzle having a part of an outer peripheral surface of the plate-like member as a part of an inner wall connected to the discharge port unit. A sand collection method for collecting sand in a sand basin in which sand contained in received water sinks,
A settling step for sinking the sand into a groove provided at the bottom of the pond;
A sand collecting step for discharging fluid from the predetermined position in the extending direction of the groove to the groove and moving the sand settling in the groove toward the sand collecting pit connected to the groove by the flow of the fluid; ,
The sand collecting step is a step of discharging a fluid of 1000 liters or more and 3000 liters or less per minute.