JP2012236148A - Sand settling basin and sand collecting method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sand settling basin in which sands contained in accepted water precipitate, having a device for suppressing stirred up of sands while moving the sands sufficiently.SOLUTION: The sand settling basin in which the sands contained in the accepted water precipitate includes: a transfer path 3 which is provided on a basin bottom and extends in a predetermined direction, and in which the precipitating sands deposit; a discharge port 7 which discharges a fluid in a predetermined direction to the sands depositing in the transfer path 3; and a cover member 38 which covers a part on a shaft L extending from the center of the discharge port 7 toward a predetermined direction in the transfer path 3 from above. The cover member 38 has an inclined portion 380 that inclines downward in a width direction of the transfer path 3.

Description

  The present invention relates to a sand basin in which sand contained in received water sinks.

  In the sewage treatment system, sewage such as sewage or rainwater is accepted, the sand contained in the sewage is settled to the bottom of the pond, and then moved in a predetermined direction to collect the sand deposited on the pond bottom. Some sand ponds are provided to remove sand from sewage. This sand settling basin is known to include sand collecting means for moving sand accumulated on the bottom of the pond in a predetermined direction by the flow of fluid discharged from a discharge port. In the sand collection using this fluid, the accumulated sand may be rolled up by the discharged fluid, and it is important how to prevent the sand from rolling up. Conventionally, an inclined plate inclined downward in a predetermined direction is disposed above a transfer path extending in a predetermined direction at an interval, and the inclined plate attempts to prevent sand from rolling up (for example, (See Patent Document 1).

Japanese Patent Laid-Open No. 9-70503

  However, in the inclined plate shown in Patent Document 1, the inclined plate is disposed so as to face the discharge direction of the fluid from the discharge port, so that the fluid discharged from the discharge port is blocked and the sand is sufficient. There is a risk of not moving. For this reason, if the discharge pressure of the discharge port is increased so as to sufficiently move the sand, the sand may be rolled up along the inclined plate by the momentum of the discharged fluid.

  In view of the above circumstances, an object of the present invention is to provide a sand basin that has been devised to suppress sand rolling while sufficiently moving sand.

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 transfer path provided at the bottom of the pond, extending in a predetermined direction, and depositing sedimented sand;
A discharge port for discharging fluid in the predetermined direction with respect to the sand accumulated in the transfer path;
A covering member that covers, from above, a portion on an axis extending in the predetermined direction from the center of the discharge port in the transfer path;
The covering member has an inclined portion inclined downward in the width direction of the transfer path.

  According to the sand basin of the present invention, since the inclined portion is inclined in the width direction, it does not block the fluid discharged from the discharge port. In addition, the inclined portion is not disposed so as to face the direction in which the fluid is discharged from the discharge port, and sand is unlikely to roll up along the inclined portion.

  Here, it is preferable that the covering member covers the portion with an interval in the vertical direction from above.

  The inclined portion may have a flat plate shape or a curved surface shape. Moreover, when the said inclination part is curved surface shape, it is preferable that it is the curved shape which made the upper part convex.

  The discharge shaft extends over the entire length of the transfer path, but the covering member covers a part or all of the discharge shaft from above. The covering member is provided along the transfer path.

  The transfer path may be flat. The transfer path may be formed in a groove shape having an opening at an upper end formed by a groove forming wall. The entire space defined by the groove forming wall may not be used as the transfer path, but a part of the lower side of the space may be used as the transfer path. Further, the inclined portion may have a lower end positioned above the upper edge of the groove forming wall, or may be positioned at the same height as the upper edge. Alternatively, the inclined portion may have a lower end positioned below the upper edge, and in this case, a part of the inclined portion enters a space defined by the groove forming wall. It will be out.

  Moreover, the aspect provided with the sand collection pit which was provided in the said pond bottom part and the said transfer path | route connected was sufficient.

  Further, the covering member may have an inverted V-shaped cross-sectional shape upside down, or a shape of the upper half of the outline of a peach or chestnut shape. Alternatively, it may have a shape obtained by connecting arc-shaped curves.

  Further, in the sand basin of the present invention, the transfer path is an aspect in which a center part in the width direction is covered with the covering member and both end parts in the width direction are open. For example, the transfer path includes both ends in the width direction. The part may be open upward.

  According to this aspect, the center of the discharge port is located in the center portion in the width direction, and the sand that has settled enters the transfer path from both ends in the width direction opened upward and accumulates in the transfer path.

Further, in the sand basin of the present invention, the transfer path is formed by a groove forming wall, and is a groove-shaped one having an opening at the upper end,
It is preferable that the groove forming wall has a curved portion that enters the center in the width direction at the upper end portion.

  That is, the curved portion is curved with the groove-shaped transfer path protruding outward, and acts as a cache against the sand that is about to roll up along the groove forming wall, along the groove forming wall. The sand to be rolled up is returned to the transfer path.

  Moreover, the sand basin of this invention WHEREIN: It is preferable that the said cover member has a sharp upper end.

  Since the upper end is sharp, the sand hardly accumulates on the covering member, and the sand that has settled on the covering member tends to flow down to the transfer path through the inclined portion.

Furthermore, in the sand basin of the present invention, a dust remover that is disposed closer to the water receiving port than the transfer path and blocks passage of contaminants longer than a predetermined length out of contaminants mixed in the received water. Prepared,
The transfer path is formed by a groove forming wall and has a groove shape having an opening at the upper end,
The covering member is preferably separated from the upper end of the groove forming wall by the predetermined length or more.

  By carrying out like this, the sand which has settled becomes easy to enter by a transfer path from an open part, and it can also prevent that an open part gets blocked.

  The covering member may have a lower end portion separated from the upper end portion of the groove forming wall by the predetermined length or more. Alternatively, the transfer path may be such that both end portions in the width direction are opened more than the predetermined length as viewed in the width direction.

  ADVANTAGE OF THE INVENTION According to this invention, the sand basin in which the device which suppresses rolling-up of sand was made | formed while moving sand enough 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 perspective view shown centering on the connection location of a 1st U-shaped member and a 2nd U-shaped member, (b) is the connection location shown to the same figure (a). It is a fragmentary sectional view. 2A is a cross-sectional view taken along the line CC of FIG. 2 showing a trough and a discharge nozzle, and FIG. 4B is a plan view of the portion shown in FIG. FIG. 5 is a DD cross section of FIG. (A) is the fragmentary sectional view which expanded and showed the uppermost flow end vicinity of the 1st U-shaped member, (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 figure which shows the example which changed the shape and arrangement position of the covering member, or the shape of the trough. (A) is a figure which shows the modification of the example shown in FIG.8 (d), (b) is a figure which shows the modification of the example shown in FIG.8 (c). It is a fragmentary sectional view showing the modification of a discharge nozzle. It is sectional drawing which cut | disconnected the sand basin 10 which is 2nd Embodiment in the center of the width direction. It is a block diagram of the water supply equipment provided in the sand basin 10 shown in FIG. It is the schematic diagram which looked at the sand basin 100 which is 3rd Embodiment from the sand collection pit side.

  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 settling basin 1 is a rectangular pond that includes a dust remover 2, a trough 3, a sand collecting pit 4, and a pump well 5. Hereinafter, in the sand basin 1, the long side direction may be referred to as the longitudinal direction, and the short side direction may be referred to as the width direction. The sand basin 1 shown in FIG. 1 accepts sewage from the right side of the figure, and the accepted water slowly flows toward the left side of the figure (see the straight arrows shown in FIG. 2). That is, the longitudinal direction of the sand basin is the direction of water flow, and in FIGS. 1 and 2, the right side of the figure is the upstream side and the left side is the downstream side.

  The dust remover 2 is for removing contaminants mixed in the sewage flowing into the sand basin 1, and is installed upstream of the trough 3. The dust remover 2 includes an endless chain 21, a plurality of rakes 22 attached to the endless chain 21 at intervals, and a filtration screen 23 that is submerged in water. The endless chain 21 is provided so as to stand obliquely on both sides in the width direction of the sand basin 1 and is wound around a ground-side sprocket 211 and a pond bottom-side sprocket 212 as shown in FIG. Yes. When the endless chain 21 is driven, the rake 22 enters and exits the water. The filtration screen 23 is disposed on the downstream side of the endless chain 21. The filter screen 23 is formed by arranging bars extending in the vertical direction at a predetermined interval (for example, 25 mm to 75 mm), and blocks the passage of contaminants having a size greater than the predetermined interval. The contaminants blocked by the filter screen 23 are lifted up by the rake 22, and the lifted contaminants are placed on a conveying means such as a belt conveyor (not shown) on the ground side.

  The trough 3 is provided at the bottom of the sand basin 1. An inclined surface 6 is provided at the bottom of the pond as described later, 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.

  As shown in FIG. 1, the trough 3 is provided at the center in the width direction of the sand basin 1 and extends in a predetermined direction from a position downstream of the dust remover 2. That is, it extends toward the sand collecting pit 4. The sand deposited on the trough 3 is moved to the sand collecting pit 4 by the flow of water discharged from a discharge port described later. In FIG. 1, a discharge axis L extending in the predetermined direction from the center of the discharge port is indicated by a one-dot chain line. In other words, the discharge axis L is an extension line obtained by extending the center line of the discharge port in a predetermined direction, and corresponds to an example of the axis referred to in the present invention.

  The sand basin 1 shown in FIG. 1 also includes a covering member 38 that covers the portion of the discharge shaft L in the trough 3 from above. The length of the covering member 38 is the same as the entire length of the trough, and the covering member 38 extends along the trough 3. Detailed description of the covering member 38 will be described later.

  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 plate thickness of 4 mm into a U-shaped cross section.

  FIG. 3A is a perspective view illustrating the connection portion between the first U-shaped member 31 and the second U-shaped member 32 as a center. In FIG. 3A, the trough 3 is shown as being transparent. Moreover, FIG.3 (b) is a fragmentary sectional view of the connection location shown to the figure (a). In addition, the arrow in FIG. 3 shows the moving direction of sand.

  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 processing 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. In addition, although the connection location of the 2nd U-shaped member 32 and the 3rd U-shaped member 33 differs in the size from the connection location shown to Fig.3 (a), description is abbreviate | omitted.

  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 configured 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. . The groove forming wall 30 forms a groove G extending in the longitudinal direction from the upstream side of the sand settling basin 1 to the sand collecting pit 4, and the most downstream end of the groove G is connected to the sand collecting pit 4. Yes. A space from the bottom of the groove G to a height position of about 3/4 is assumed as a transfer path.

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. 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 discharge port 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 C-C in FIG. 2 showing the trough 3 and the discharge nozzle 7. FIG. 4B shows the portion shown in FIG. It is a top view. 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.

  Further, as shown in FIG. 4A, the height positions of the opening facing upward in the first U-shaped member 31 and the opening facing upward in the second U-shaped member 32 are aligned. Yes. That is, the height positions of the upper edge 312 of the first U-shaped member 31 and the upper edge 322 of the second U-shaped member 32 coincide with each other.

  Further, FIG. 4A also shows a covering member 38 having an inverted V-shaped cross section. That is, FIG. 4A shows a first covering member 381 positioned above the first U-shaped member 31 and a second covering member 382 positioned above the second U-shaped member 32. Has been. Although not shown here, a third covering member 383 (see FIG. 5) is disposed above the third U-shaped member 33. In the following description, the first covering member 381, the second covering member 382, and the third covering member 383 are collectively referred to as the covering member 38. The covering member 38 is for suppressing sand from rolling up by the fluid discharged from the discharge port. The covering member 38 is supported by support members 39 fixed to the upper ends on both sides of the trough 3. The support member 39 is provided at a predetermined interval in the extending direction of the trough 3, and a space 37 between the support member 39 and the supporting member 39 in the extending direction of the trough 3 is opened upward (FIG. 1). reference). The length of the support member 39 in the extending direction is equal to or longer than the predetermined interval in the filtration screen 23, and is 200 mm here. By setting the support member 39 to such a length, it is possible to prevent the contaminants (slag) that has passed through the filtration screen 23 from being wound around the support member 200. Moreover, it is preferable to arrange the support member 39 at least near the downstream side of the discharge port. Sand is most easily rolled up in the vicinity of the downstream side of the discharge port, and the support member 39 also functions as a covering member, so that the sand can be more effectively prevented from rolling up. In the present embodiment, the covering member 38 and the support member 39 are integrally formed.

  The cover member 38 is formed by bending a single plate member 90 degrees, flat-plate inclined portions 380 are formed on both sides in the width direction of the trough 3, and the upper end 38a is sharp. The inclined portion 380 is inclined at an angle of 45 degrees downward in the width direction of the trough 3. The sand also sinks to the covering member 38, but the sand is not easily deposited on the upper end 38a portion because the upper end 38a is sharp, and the sand that has settled on the covering member 38 passes through the inclined portion 380, It becomes easy to flow into the trough 3 from 37 between the support member 39 and the support member 39 (see FIG. 1). Further, the height position of the lower end 38b of the covering member 38 having an inverted V-shaped cross section in the present embodiment is the upper edge 312 of the first U-shaped member 31 and the upper edge 322 of the second U-shaped member 32. It corresponds to the height position of.

  The support member 39 is preferably provided with an inclined portion in the same manner as the cover member 38. That is, it is preferable that the upstream half of the support member 39 is inclined downward toward the upstream side, and the downstream half is inclined downward toward the downstream side. By doing so, it is possible to prevent sand from accumulating on the support member 39.

  FIG. 5 is a diagram showing the pond bottom side of the DD cross section of FIG. 2. 4 is the same as FIG. 4 above, but FIG. 5 is also a cross-sectional view at a position where the support member 39 is not provided. In FIG. 5, the background is omitted. Accordingly, in FIG. 5, the third covering member 383 is shown, but the first covering member 381 and the second covering member 382 that should be visible on the back side are omitted, and should also be visible on the back side. The support member 39 is also not shown.

  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 flows down further toward the trough 3 along the inclined surface 6, and the sedimented sand can be collected in the groove G. FIG. 5 shows a state in which the sand S that has settled on the inclined surface 6 flows down toward the trough 3 and the sand S is accumulated in the trough 3. In the trough 3 shown in FIG. 5, sand S is accumulated from the bottom of the groove G to about half the height position, and water is discharged from a third discharge port 73 (see FIG. 7) (not shown) here. Then, the inside of the trough 3 becomes a transfer path. In addition, the inclination angle of the pond bottom may be, for example, 30 degrees or 60 degrees.

  Further, FIG. 5 shows an arrow W representing the length in the transfer path width direction (trough width direction) between the support member 39 and the support member 39 37 (see FIG. 1). This length is also equal to or longer than the predetermined interval in the filtration screen 23, and is 100 mm here. By setting it to such a length, the sand S that has flowed down along the inclined surface 6 can be easily flown down by the trough 3, and it is also possible to prevent the gap 37 from being clogged. A space 37 between the support member 39 and the support member 39 (see FIG. 1) corresponds to an example of an open portion according to the present invention.

  FIG. 6A is an enlarged partial cross-sectional view showing the vicinity of the most upstream end of the first U-shaped member 31. In FIG. 6A, the right side of the figure is the upstream side, and the left side of the figure is the downstream side.

  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.

  FIG.6 (b) is the fragmentary sectional view which looked at Fig.6 (a) from the left. That is, FIG. 6B is a view of the end face wall 36 viewed from the downstream side, and the back side of the paper surface is the upstream side.

  As shown in FIG. 6B, the end face wall 36 is provided with a second discharge port 72. 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, a third discharge port 73 and a third water supply pipe 23 provided at the step portion between the second U-shaped member 32 and the third U-shaped member 33 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. When the sewage flowing into the sand basin 1 passes through the dust remover 2 shown in FIG. 2, contaminants mixed in the sewage are removed. The sewage that has passed through the dust remover 2 reaches the upstream end of the trough 3 and further flows in the direction in which the trough 3 extends. While the sewage flows through the upstream portion of the trough 3, the sand contained in the sewage sinks to the bottom of the sand basin 1. As described above, in this portion, the sand that has settled on the inclined surface 6 also flows down toward the trough 3 along the inclined surface 6. Further, the sand that has settled down to the covering member 38 flows down into the trough 3 from 37 (see FIG. 1) between the support member 39 and the support member 39 through the inclined portion 380. Thus, sand 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. That is, the sand moves to the sand collecting pit 4 side through the transfer path. When the sand moves along the transfer path, the sand is likely to roll up due to the momentum of the water discharged from the second discharge port 72, but the floating sand hits the covering member 38 and goes further upward. It fits in the groove G. Since the inclined portion 380 of the covering member 38 is inclined in the width direction of the transfer path, it does not block water discharged from the second discharge port 72. In addition, the inclined portion 380 is not disposed so as to face the direction in which water is discharged from the second discharge port 72, and the sand is difficult to roll up along the inclined portion 380.

  In addition, according to research of this inventor, in the sand settling basin in which the sewage was put into the bottom of the inner peripheral surface of the U-shaped member until the water depth reached a position of 2 m, the U shape having the same shape as the first U-shaped member 31 Using a letter-shaped member, sand is further deposited from the upper part of the U-shaped member to about 100 mm, and water is discharged at a discharge flow rate of 16 m / sec, 3000 liters per minute, 2000 liters per minute, and 1000 liters per minute. It was found that even when the discharge time was increased unnecessarily, the sand could not be moved efficiently, and the water discharge time during which the sand could be moved efficiently was about 5 minutes. In addition, when the water discharge time is 5 minutes, when 1000 liters of water is discharged, the sand travel distance is just over 6 meters, and at 2000 liters per minute, the sand travel distance is about 12 meters, 3000 meters per minute. It was also found that the distance traveled by sand was about 18 meters.

  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. That is, the sand further moves to the sand collecting pit 4 side through the transfer path. At this time, the sand is likely to roll up due to the momentum of the water discharged from the first discharge port 71, but the cover member 38 suppresses the roll-up as described above.

  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. That is, the sand reaches the sand collecting pit 4 side through the transfer path. At this time, the sand is likely to be rolled up by the momentum of the water discharged from the third discharge port 73, but the covering member 38 suppresses the roll-up as described above.

  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. If it is faster than 24 m / sec, it cannot be said that there is no risk of sand coming out from the space 37 between the support member 39 and the support member 39 (see FIG. 1). Is preferably suppressed to 24 m / sec or less. 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, the discharge pressure of water in each discharge port 71, 72, 73 is 0.1 MPa or more and 0.3 MPa or less.

  As described above, in the sand settling basin 1 of the present embodiment, the sand rolling-up can be suppressed by the covering member 38 while sufficiently moving the sand. Further, the discharge ports 71, 72, 73 are arranged at intervals in the extending direction (longitudinal direction) of the groove G, and 2000 liters of water per minute from the discharge ports 71, 72, 73 to the groove G in order. Since it is discharged, 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 component names as those described so far may be given the same reference numerals as those used so far, and redundant description will be omitted.

  FIG. 8 is a diagram showing an example in which the shape and arrangement position of the covering member or the shape of the trough are changed. In FIG. 8, the width direction of the trough is the left-right direction of the figure. Moreover, the space below the groove formed in the trough becomes a transfer path.

  8A and 8B, a trough 305 having a 3/4 arc-shaped inner peripheral surface 3051 is provided with a covering member 385 in the shape of the upper half of the outline line having a peach-shaped cross section. An example of placement is shown.

  The inner peripheral surface 3051 of the trough 305 shown in FIG. 8A and FIG. 8B has a curved portion 3051a that enters the trough width direction center side at the upper end portion. The curved portion 3051a acts as a sand for the sand that is about to roll up along the inner peripheral surface 3051 of the trough 305, and winds along the inner peripheral surface 3051 as shown by the arrows in FIG. The sand that is about to rise is returned to the transfer path.

  Further, it can be said that the covering member 385 shown in FIGS. 8A and 8B has the shape of the upper half of the outline of the chestnut-shaped cross section. The covering member 385 also has an inclined portion 3851 inclined downward in the width direction of the trough 305 (width direction of the transfer path). The inclined portion 3851 shown in FIG. 8A and FIG. 8B is opened at an angle of 90 degrees, and the lower portion is formed of a curved surface. Here, the lower part is formed of an arcuate curved surface having a radius of 150 mm. The upper end 385a of the covering member 385 is pointed, and the lower end 385b thereof is almost directly below, that is, faces the sand conveyance path, and the sand that has settled down to the covering member 385 easily flows down to the sand conveyance path through the inclined portion 3851. . Further, the sand that tends to roll up in the extending direction (predetermined direction) of the trough 305 by the momentum of the water discharged from the discharge port is suppressed by the covering member 385 extending in the predetermined direction.

  In the covering member 385 shown in FIG. 8A, the height position of the lower end 385 b coincides with the height position of the upper end 3052 of the trough 305. A distance W1 between the lower end 385b of the covering member 385 and the upper end 3052 of the trough 305 is a length equal to or longer than the predetermined interval in the filtration screen 23 shown in FIG. 2, and is 100 mm here.

  8B, the height position of the lower end 385b is lower than the height position of the upper end 3052 of the trough 305, and the height position of the upper end 385a is the height of the upper end 3052 of the trough 305. It is above the vertical position. That is, the cover member 385 shown in FIG. 8B has a lower end portion entering the trough 305. The covering member 385 is separated from the upper end 3052 of the trough 305 by a distance W2 that is equal to or greater than the predetermined interval in the filtration screen 23 shown in FIG. Further, the lower end 385b of the covering member 385 is also separated from the inner peripheral surface 3051 of the trough 305 by a distance W3 that is not less than the predetermined interval in the filtration screen 23 shown in FIG. The distances W1 to W3 described above are all distances in the trough width direction.

  8C shows a trough 306 in which the area of the bottom portion of the trough shown in FIG. 8A and FIG. 8B is reduced, and a covering member 385 shown in FIG. 8A and FIG. An example in which is arranged is shown.

  The inner peripheral surface 3061 of the trough 306 shown in FIG. 8C also has a curved portion 3061a that acts as a bite at the upper end portion. Moreover, in the trough 306 shown in FIG.8 (c), since the area of the bottom part of a trough is narrow, the area of the bottom part of a transfer path | route becomes narrow, and it is easy to move sand on the transfer path | route.

  Further, in the covering member 385 shown in FIG. 8C, the height position of the lower end 385 b is higher than the height position of the upper end 3062 of the trough 306. That is, the covering member 385 is disposed above the trough 306, and the lower end 385b of the covering member 385 is separated from the upper end 3062 of the trough 306 by a distance W4 that is equal to or greater than the predetermined interval in the filtration screen 23 shown in FIG. Yes. The distance W4 here is the shortest distance connecting the lower end 385b of the covering member 385 and the upper end 3062 of the trough 306, and is 100 mm away here.

  FIG. 8D shows a trough 307 in which a curved portion is provided on the U-shaped trough 3 shown in FIG. 3 and the like. That is, the inner peripheral surface 3071 of the trough 307 shown in FIG. 8D includes a curved portion 3071a that is curved with the outer side convex, a flat portion 3071b that is an intermediate portion in the vertical direction, and a semicylindrical portion 3071c that is a bottom portion. Have This curved portion 3071a also acts as a bite against the sand that is about to roll up along the inner peripheral surface 3071 of the trough 307, and winds along the inner peripheral surface 3071 as shown by the arrow in FIG. The sand that is about to rise is returned to the transfer path.

  The cover member 38 shown in FIG. 8D is the same as the inverted V-shaped cover member 38 shown in FIG. 4A and the like, and a pair of flat inclined portions 380 are provided. The covering member 38 is disposed above the trough 307, and the interval L <b> 1 in the width direction at the lower ends of the pair of inclined portions 380 is longer than the length L <b> 2 in the width direction of the opening of the trough 307. Further, the lower end 38b of the covering member 38 is separated from the upper end 3072 of the trough 307 by a distance W5 that is equal to or larger than the predetermined interval in the filtration screen 23 shown in FIG. The distance W5 here is the shortest distance as well as the distance W4, and is 80 mm away here. The sand which is going to roll up in the extending direction (predetermined direction) of the trough 307 by the momentum of water discharged from the discharge port is suppressed by the covering member 38 extending in the predetermined direction.

  In the example described so far, the widthwise interval at the lower ends of the pair of inclined portions of the cover member is shorter than the length of the trough opening in the widthwise direction, but the cover member is more than the predetermined interval than the trough. As long as it exists above, the space | interval may be the same as the length of the width direction of the opening of a trough.

  As described above, in any of the examples described with reference to FIG. 8, since the distances W1 to W5 are equal to or greater than the predetermined interval, the sand that has flowed down along the inclined surface 6 shown in FIG. Further, it is possible to prevent clogging between the support member 37 (see FIG. 1) which is not shown here.

  In addition to this, the shape of the trough may be formed in a semicircular shape, may be a rectangular shape with an upper opening, or may be a semi-oval tube shape with a radius of curvature that decreases toward the lower side. Good. 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.

  The covering member may have a semicircular cross-sectional shape or a shape obtained by connecting arc-shaped curves. Further, all the inclined portions of the covering member shown in FIG. 8 are opened at an angle of 90 degrees, but may be a predetermined angle that falls within a range of 30 degrees or more and 90 degrees or less.

  Fig.9 (a) is a figure which shows the modification of the example shown in FIG.8 (d).

  FIG. 9A shows the same trough 307 as the trough shown in FIG. 9A also shows inclined surfaces 6 provided on both sides of the trough 307 in the width direction. The inclined surface 6 is inclined downward by θ1 (here 45 degrees) toward the trough 307. As shown in FIG. 9A, the opening 307a of the trough 307 is narrowed.

  The covering member 386 shown in FIG. 9A is an inverted V-shaped covering member, but the angle (θ2) at which the inclined portion 3861 is opened is 60 degrees. The covering member 386 is also disposed above the trough 307, and the trough width direction interval L1 at the lower end 386b of the pair of inclined portions 3861 is longer than the trough width direction length L2 of the opening of the trough 307. The opening 307a of the trough 307 is completely covered with the covering member 386 in the width direction with a space in the vertical direction. Further, the lower end 386b of the covering member 386 is separated from the inclined surface 6 by a distance W6 that is equal to or greater than the predetermined interval in the filtration screen 23 shown in FIG. The distance W6 here is the shortest distance connecting the lower end 386b of the covering member 386 and the inclined surface 6, and is 100 mm away here. Note that the lower end 386b of the covering member 386 may be installed at a distance W7 greater than or equal to the predetermined interval in the trough width direction with respect to the inclined surface 6.

  In the modification shown in FIG. 9A, the sand slides on the inclined surface 6 and falls into the transfer path from the opening 307a of the trough 307, and the fallen sand is applied to the inner peripheral surface 3071 by the momentum of the water discharged from the discharge port. Even if it is likely to roll up along the curved surface 3071a of the trough 307, the sand which is going to roll up along the inner peripheral surface 3071 moves as indicated by the arrow shown in FIG. Return to the path. Further, the sand that is going to roll up in the extending direction (predetermined direction) of the trough 307 by the momentum of the water discharged from the discharge outlet is suppressed by the covering member 386 extending in the predetermined direction.

  FIG. 9B is a diagram showing a modification of the example shown in FIG.

  FIG. 9B shows a trough 306 that is the same as the trough shown in FIG. Further, the covering member 387 shown in FIG. 9B has the same shape as the covering member 385 shown in FIG. The covering member 387 completely covers the opening 306a of the trough 306 in the width direction with an interval in the vertical direction. The lower end 387b of the covering member 387 shown in FIG. 9B is separated from the upper end 3062 of the trough 306 by a distance W8 that is equal to or greater than the predetermined interval in the filtration screen 23 shown in FIG. The distance W8 here is the shortest distance connecting the lower end 387b of the covering member 387 and the upper end 3062 of the trough 306, and is 100 mm away here.

  The sand that is going to roll up along the inner peripheral surface 3061 due to the momentum of the water discharged from the discharge port once jumps out of the opening 306a of the trough 306 as shown by the curved arrow shown in FIG. 9B. The cover member 387 is reversed to return to the transfer path. Moreover, the sand which is going to roll up in the extending direction (predetermined direction) of the trough 306 by the momentum of the water discharged from the discharge outlet is suppressed by the covering member 387 extending in the predetermined direction.

  In the example shown in FIG. 9 described above, the interval in the trough width direction at the lower end of the covering member is longer than the length in the width direction at the opening of the trough (groove), but the interval may be the same as the length. . That is, the width in the trough width direction at the lower end of the covering member may be equal to or longer than the length in the width direction at the opening of the trough (groove).

  FIG. 10 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.

  Moreover, it is preferable that the water discharged from each discharge port 71,72,73 is 1000 liters or more and 3000 liters or less per minute, and does not necessarily need to be 2000 liters per minute. In the case of less than 1000 liters per minute, the sand accumulated in the groove G may hardly move. If there is more than 3000 liters per minute, it cannot be said that there is no risk of sand coming out from the space 37 between the support member 39 and the support member 39. Is preferably suppressed to 3000 liters per minute or less. 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, if the discharge flow rate is increased to 3200 liters per minute, there is no risk that sand may come out from the space 37 between the support members 39 and 39. It will not cut.

  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, it is preferable that the amount of water discharged from each discharge port is within a range of 1000 liters to 3000 liters per minute, and a larger amount can increase the distance of sand movement. it can. 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 following description, 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 redundant description is omitted.

  FIG. 11 is a cross-sectional view of the sand basin 10 according to the second embodiment cut at the center in the width direction. Also in FIG. 11, the right side of the figure is the upstream side and the left side is the downstream side.

  The sand basin 10 of the second embodiment is different 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 the second 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.

  In addition, although the same dust remover 2 as the dust remover 2 shown in FIG. 2 is installed further upstream from the upstream trough 8, it is not shown in FIG.

  Further, a covering member 38 having a reverse V-shaped cross-sectional shape is provided above the upstream trough 8 and the downstream trough 9 as in the covering member 38 shown in FIG.

  The end of the upstream trough 8 opposite to the sand collecting pit 4 and the end of the downstream trough 9 opposite to the sand collecting pit 4 are the same as those shown in FIG. 6B, the upstream discharge port 81 (see FIG. 12) is provided on the downstream side surface of the end wall attached to the upstream trough 8, and the downstream trough 9 has the same configuration as that shown in FIG. The downstream discharge port 91 (refer FIG. 12) is provided in the upstream side surface of the end surface wall attached to the. In the second embodiment, an 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 surface 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. When water is discharged from the upstream discharge port 81 (see FIG. 12), the inside of the upstream trough 8 becomes a transfer path, and when water is discharged from the downstream discharge port 91 (see FIG. 12), the downstream trough 9 is the transfer path.

  FIG. 12 is a block diagram of a water supply facility provided in the sand 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.

  In the sand basin 10 shown in FIG. 11, the water supply pump P is driven, and first, the motor-operated 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. In this manner, the sand moves to the sand collecting pit 4 through the transfer path in the upstream trough 8 and the transfer path in the downstream trough 9. When the sand moves along the transfer path, the sand is likely to roll up due to the momentum of the discharged water, but the lifted sand hits the covering member 38 and does not go upward anymore and fits in the groove G. . Further, the covering member 38 does not block water discharged from the upstream discharge port 81 or the downstream discharge port 91. Further, the covering member 38 is not disposed so as to face the direction in which water is discharged from the upstream discharge port 81 or the downstream discharge port 91, and sand is unlikely to roll up along the covering member 38. 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, even in the sand basin 10 of the second embodiment, the sand rolls can be suppressed by the covering member 38 while sufficiently moving the sand. Further, an upstream discharge port 81 is disposed at the upstream end portion of the upstream groove forming wall 80, and a downstream discharge port 91 is disposed at the downstream end portion of the downstream groove forming wall 90. Since 2000 liters of water is discharged toward the upstream groove G and the downstream groove G, the sand accumulated in the groove can be efficiently moved a predetermined 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 is shortened. 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, to summarize the sand basin described above, in the sand basin in which the sand contained in the received water sinks, a groove forming wall that is provided at the bottom of the pond and forms a groove in which the sedimented sand accumulates, and the pond A sand collection pit provided at the bottom and connected to the groove, and a discharge port that is disposed on the groove forming wall and includes one or a plurality of discharge ports that discharge fluid from the predetermined position in the extending direction of the groove to the groove It can also be said that the discharge port unit is a sand basin characterized by discharging fluid of 1000 liters to 3000 liters per minute. According to this sand settling basin, 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.

  Moreover, it is preferable that the said pond bottom part is provided with the bottom face continued to the said groove | channel, and the said bottom face inclines below toward the said groove | channel. Since the bottom surface is inclined toward the groove, the sedimented sand can be collected in the groove.

  Further, the groove forming wall has an extending portion extending toward the sand collecting pit at a wall bottom portion, and the discharge port discharges fluid along the extending portion. It is preferable. By doing so, the sand can be efficiently moved along the groove.

  Further, the groove forming wall has a step-shaped wall bottom portion that gradually increases toward the sand collecting pit, and the discharge port unit connects the upper step portion and the lower step portion of the step-shaped wall bottom portion. It is also preferable that it is arranged at the step part. By disposing the discharge port unit in the stepped portion, the discharge port unit does not hinder sand movement.

  Furthermore, the groove forming wall is at least partly composed of an inner peripheral surface of a plate-like member, and a part of the outer peripheral surface of the plate-like member is connected to a part of the inner wall connected to the discharge port unit. It is also a preferable aspect that the discharge nozzle 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.

  In addition, the sand collection method for the sand basin described so far is a sand collection method for collecting the sand in the sand basin in which the sand contained in the received water sinks, and the sand is provided in the groove provided at the bottom of the pond. A settling step for settling into the groove, and a fluid is discharged into the groove from a predetermined position in the extending direction of the groove, and the sand settling in the groove is moved by the flow of the fluid toward the sand collecting pit connected to the groove. A sand collecting step, wherein the sand collecting step is a step of discharging fluid of 1000 liters to 3000 liters per minute.

  FIG. 13: is the schematic diagram which looked at the sand basin 100 which is 3rd Embodiment from the sand collection pit side. In FIG. 13, the back side of the paper is the upstream side, and the front side of the paper is the downstream side. Moreover, the left-right direction of FIG. 11 becomes a pond width direction.

  The sand basin 100 of the third embodiment is a so-called high pressure sand collection sand basin in which the discharge pressure of water discharged from the discharge port 101 is 0.59 MPa or more. In FIG. 13, four discharge ports 101 are shown, and a discharge shaft L extending from the center of each discharge port 101 in a predetermined direction provided with a sand collecting pit (not shown) is also shown here. The discharge axis L is an axis (extension line) extending in a direction perpendicular to the paper surface. Further, the sand basin 100 is not provided with a groove-like trough, and the pond bottom 100a is flat. The sand transfer path 103 becomes a plane portion along the discharge axis L in the pond bottom 100a. In FIG. 13, the extending direction of the transfer path 103 is also perpendicular to the paper surface, and the width direction is the left-right direction of the drawing as is the pond width direction. Further, the sand basin 100 shown in FIG. 13 is also provided with a covering member 38 having a reverse V-shaped cross section similar to the covering member 38 shown in FIG. The cover member 38 shown in FIG. 13 also covers a portion on the discharge axis L in the transfer path 103 with an interval in the vertical direction from above, and an inclined portion inclined downward in the width direction of the transfer path 103. 380.

  When high-pressure water is discharged from the discharge port 101 in a state where sand is accumulated on the pond bottom 100a, the sand moves through the transfer path 103 to a sand collecting pit (not shown). At this time, because of the high pressure water, the sand tends to roll up due to the momentum of the discharged water, but the floating sand hits the covering member 38 and does not go further upward. Also, the covering member 38 shown in FIG. 13 does not block the water discharged from the discharge port 101 and is not disposed so as to face the discharge direction of the water from the discharge port 101, and sand is covered by the cover member 38. It is difficult to roll up along 38. Thus, also in the sand settling basin 100 which implements the high-pressure sand collection of 3rd Embodiment, roll-up of sand can be suppressed by the covering member 38, moving sand enough.

DESCRIPTION OF SYMBOLS 1 Sand basin 3,305,306,307 Trough 30 Groove formation wall 3051a, 3061a, 3071a Curved part 3052,3062,3072 Upper end 4 Sand collecting pit 6 Pond bottom 7 Discharge nozzle 37 Between 38,385 Cover member 380,3851 Inclined part 38a, 385a Upper end 38b, 385b Lower end 39 Support member G Groove L Discharge shaft

Claims (5)

In the sand basin where the sand contained in the received water sinks,
A transfer path provided at the bottom of the pond, extending in a predetermined direction, and depositing sedimented sand;
A discharge port for discharging fluid in the predetermined direction with respect to the sand accumulated in the transfer path;
A covering member that covers, from above, a portion on an axis extending in the predetermined direction from the center of the discharge port in the transfer path;
The sand basin characterized in that the covering member has an inclined portion inclined downward in the width direction of the transfer path.   2. The sand basin according to claim 1, wherein the transfer path has a widthwise center portion covered with the covering member and both widthwise end portions being open. The transfer path is formed by a groove forming wall and has a groove shape having an opening at the upper end,
The sand settling basin according to claim 1 or 2, wherein the groove forming wall has a curved portion that enters the widthwise center side at an upper end portion.   4. The sand basin according to claim 1, wherein the covering member has a sharp upper end. 5. A dust remover that is disposed closer to the water receiving port than the transfer path and blocks the passage of contaminants of a predetermined length or more out of the contaminants mixed in the received water,
The transfer path is formed by a groove forming wall and has a groove shape having an opening at the upper end,
The sand basin according to any one of claims 1 to 4, wherein the covering member is separated from the upper end of the groove forming wall by the predetermined length or more.

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