JP7080479B2 - Sand carry-out equipment - Google Patents

Description

The present invention relates to a sand unloading facility in which sand contained in the received water is provided in a sand basin where the sand is settled at the bottom of the pond, and the settled sand is carried out to the outside of the settling basin.

The sewage treatment facility receives sewage such as sewage and rainwater, and the sand contained in the sewage is settled in the bottom of the pond or in the ditch provided at the bottom of the pond, and then deposited in the bottom or ditch. Some have a sand basin that collects sand in a sand collection pit at the bottom of the pond and removes it from sewage. For example, in Patent Document 1, by executing a sand removal operation at a predetermined time, accumulated sand is collected in a sand collecting pit, and the sand is pumped up together with sewage by a sand lifting pump installed in the sand collecting pit. It is disclosed that the sand settling basin is transported to a sand settling basin outside the sand basin. This pipe extends above the sand basin and extends toward the sand basin separator installed outside the basin, and extends from the sand lifting pump toward the transport pipe and extends above the sand basin. It consists of a sand basin connected to. The sand lifting pipe is provided with a valve for preventing backflow so that the sewage and sand in the pipe do not flow back and return to the sand basin when the sand lifting pump is not driven. The check valve has a type that opens and closes the valve by the driving force of the electric actuator (hereinafter referred to as an electric valve) and a type that automatically opens and closes the valve by the flow of fluid (hereinafter referred to as a check valve). There is.

Japanese Unexamined Patent Publication No. 2014-95290

The sand pump is stopped when the sand removal operation is not being performed. In addition, the sand pump may be temporarily stopped to adjust the water level of the sand basin during the sand removal work. When the sand pump is stopped, the check valve is closed. When the drive of the sand lifting pump is stopped and the check valve for preventing backflow is closed, the flow of sewage in the sand raising pipe is stopped, and the sand between the valve for preventing backflow and the transport pipe falls and is used for preventing backflow. Accumulate on the valve. If only the sand in the sand lifting pipe is used, the amount will not be large. However, the sand in the transport pipe may further enter the sand-lifting pipe, and a large amount of sand may be deposited on the check valve for preventing backflow. Both the motorized valve and the check valve have a problem that if too much sand is accumulated on the valve, the weight of the sand makes it impossible to open the valve. That is, in an electric valve, if the sand deposited on the valve becomes heavier than the driving force of the valve by the electric actuator, the valve cannot be opened. Further, in the check valve, if the sand accumulated on the valve becomes heavier than the force of the sand pump to pump up the sewage, the valve cannot be opened. When this problem occurs, a lot of labor is required to disassemble and clean the check valve for preventing backflow, or to remove the entire sand-lifting pipe to remove the sand in the sand-lifting pipe. Further, if the electric actuator or the sand-lifting pump is continuously driven while the valve cannot be opened, the electric actuator or the sand-lifting pump may overheat and be damaged.

In view of the above circumstances, it is an object of the present invention to provide a sand carrying-out facility in which defects are unlikely to occur.

The sand unloading equipment of the present invention that solves the above object is a sand unloading equipment provided in a sand basin where the sand contained in the received water settles.
A pump that sucks in the settled sand and
A sand raising pipe connected to the pump and through which sand sucked by the pump passes upward.
It is provided with a transport pipe extending in a direction intersecting with the sand lift pipe and transporting sand that has passed through the sand lift pipe.
The sand lifting pipe is provided with a check valve for preventing backflow from the transport pipe to the pump, and the sand lift in the transport pipe is provided between the backflow prevention valve and the transport pipe. It is characterized by having a portion arranged above the connection portion with the pipe.

Here, the transport pipe may extend over a plurality of the sand basins, and the sand lift pipes arranged in each of the plurality of sand basins may be connected to the transport pipe. Further, the transport pipe may be provided above the sand basin, and the pump may be arranged at the bottom of the sand basin. Further, the sand raising pipe may extend from the bottom of the sand basin toward the transport pipe above the sand basin. In addition, the sand-lifting pipe may have a portion extending in the vertical direction, and may further have a portion extending in the horizontal direction. In this case, the vertically extending portion and the horizontally extending portion may be connected by an L-shaped pipe.

According to this sand unloading facility, even if the sand in the transport pipe enters the sand-lifting pipe for some reason, the sand is the portion of the sand-lifting pipe arranged above the transport pipe. Since it is dammed in front of it, it can be prevented from accumulating on the check valve for preventing backflow. Therefore, it is possible to prevent the occurrence of a problem that the check valve for preventing backflow cannot be opened due to the accumulated sand.

Further, in this sand unloading facility, the sand lifting pipe may be connected to an upper portion of the transport pipe.

According to this aspect, the sand in the transport pipe tends to collect on the lower side of the transport pipe due to its own weight and does not easily move to the upper portion, so that it is possible to prevent the sand in the transport pipe from entering the sand lift pipe. .. This makes it possible to more reliably prevent the sand from accumulating on the check valve for preventing backflow.

Further, in this sand unloading facility, the portion of the sand lifting pipe connected to the transport pipe is inclined with respect to the transport pipe so as to gradually approach the transport pipe toward the transport direction of the transport pipe. And may be arranged.

By doing so, the sand transported in the transport pipe from the upstream side of the connection portion between the sand lift pipe and the transport pipe does not enter the sand lift pipe unless it moves against the transport direction. , The sand is suppressed from entering the sand raising pipe. Further, the sand moving from the inside of the sand-lifting pipe to the inside of the transport pipe is sent toward the transport direction and moves to the downstream side as it is along with the flow of sewage in the transport pipe, so that the sand returns to the inside of the sand-lifting pipe. It is suppressed from coming. Further, since the sewage in the sand raising pipe is sent in the transport direction in the transport pipe, the flow of the sewage in the transport pipe can be assisted by the fed sewage.

According to the present invention, it is possible to provide a sand carrying-out facility in which defects are less likely to occur.

It is a schematic sectional drawing of the sewage treatment facility including the sand basin corresponding to one Embodiment of this invention. It is a top view of the sand basin corresponding to one Embodiment of this invention. It is XX sectional view of the sand basin shown in FIG. (A) is an enlarged view showing the Z portion of FIG. 3 in an enlarged manner, and FIG. 4 (b) is a schematic perspective view showing a first covering member and an upstream trough first nozzle. FIG. 2 is a cross-sectional view taken along the line AA of the sand basin shown in FIG. It is an enlarged view which shows the part B of FIG. 5 enlarged. (A) is a cross-sectional view for explaining a state in which one pipe provided with a lap joint is connected to the other pipe, and (b) is one in which a lap joint is provided by loosening a bolt. It is sectional drawing for demonstrating the state which the tube of 1 is rotatable about the axial direction with respect to the other tube. (A) is a sectional view taken along the line CC of FIG. 6, and FIG. 6 (b) is a sectional view similar to (a) for explaining a change in a discharge direction by a sand collecting nozzle. It is a schematic cross-sectional view of four sewage treatment facilities cut in the pond width direction at the sand collection pit part and seen in the longitudinal direction. It is a skeleton diagram which shows the sand-lifting pump, the sand-lifting pipe, the transport pipe, and the sand-sinking separator. (A) is an enlarged view showing the part E of FIG. 9 in an enlarged manner, and (b) is an enlarged view of the figure (a) seen from the upstream side in the transport direction of the transport pipe. It is a water supply system diagram in a sewage treatment facility. It is explanatory drawing which shows the water level of a sand basin and a water level sensor. It is a flowchart which shows the flow of the sand removal operation in a sewage treatment facility. It is sectional drawing of the sand basin similar to FIG. It is the same cross-sectional view as FIG. 3 which shows the modification of the connection surface. (A) is a diagram showing a first modified example of the supply pipe and the sand collecting nozzle shown in FIG. 8, and (b) is a diagram showing a second modified example of the supply pipe and the sand collecting nozzle shown in FIG. be. It is a cross-sectional view similar to FIG. 5 which shows the deformation example of a main trough, a covering member, and a bottom plane. FIG. 8 is a cross-sectional view similar to FIG. 8A showing a bottom plane near the upstream end of the sand pond and a bottom plane near the sand collecting pit in the modified example shown in FIG. It is the same explanatory diagram as FIG. 13 which shows the detection example of the water level when the height of the main trough is raised.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The sand basin according to the embodiment of the present invention is arranged in a sewage treatment facility, and after sedimenting sand contained in sewage such as sewage and rainwater, the sedimented sand is moved to a sand collecting pit and removed from the sewage. It is a thing.

FIG. 1 is a schematic cross-sectional view of a sewage treatment facility including a sand basin corresponding to an embodiment of the present invention.

As shown in FIG. 1, the sewage treatment facility 1 has a sand basin 2, a pump well 3, and a dam device 4. Sewage such as sewage and rainwater flows into the sewage treatment facility 1. Four sewage treatment facilities 1 of the present embodiment are provided in parallel with respect to the flow direction of sewage. Since each sewage treatment facility 1 has the same configuration, one of them will be described first. The sewage treatment facility 1 receives sewage from the left side in FIG. The received sewage slowly flows toward the pump well 3 on the right side of the figure while sinking the sand contained in the sewage in the sand basin 2 (see the straight arrow shown in FIG. 1). Hereinafter, the upstream side of the received sewage flow is simply referred to as an upstream side, and the downstream side of the sewage flow is simply referred to as a downstream side.

A dam device 4 is arranged on the upstream side of the sewage treatment facility 1 with respect to the sand basin 2. The dam device 4 has an opening wall 41, an inflow gate 42, and a gate drive device 43. The wall surface on the downstream side of the opening wall 41 defines the upstream end of the sand basin 2. An inflow port 411 is opened at the lower end portion of the opening wall 41. The inflow gate 42 is provided so as to be movable up and down along the wall surface on the upstream side of the opening wall 41. When the inflow gate 42 is located at the lower position shown by the solid line in FIG. 1, the inflow port 411 is blocked to block the inflow of sewage upstream of the dam device 4 into the sand basin 2. Further, when the inflow gate 42 is pulled up to the upper position shown by the alternate long and short dash line in FIG. 1, sewage is allowed to flow into the sand basin 2. The gate drive device 43 has a drive mechanism (not shown) inside thereof, and moves the inflow gate 42 up and down in response to a command from a control device that controls the dam device 4. By this vertical movement, the inflow gate 42 is selectively arranged at either the upper position or the lower position.

The sand basin 2 is provided with a dust remover 5 arranged on the upstream side thereof, a sand collecting pit 6 arranged near the middle course, and a sand pump 61 for carrying out the sand in the sand collecting pit 6 to the outside of the pond. Has been done. A sand lifting pipe 64 is connected to the sand pump 61. The sand sucked by the sand-lifting pump 61 passes through the sand-lifting pipe 64 and is sent to a sand-sinking machine SS (see FIG. 10) provided outside the sand-sinking basin 2. The dust remover 5 is for removing contaminants (residues) mixed in the sewage that has flowed into the sand basin 2. The configuration of the sand basin 2 will be described in detail later.

A pump well 3 is formed on the downstream side of the sewage treatment facility 1 with respect to the sand basin 2. Sewage from which sand has been removed by the sand basin 2 is stored in the pump well 3. The bottom of the pump well 3 is the deepest part of the sewage treatment facility 1. A pump well 31 and a water supply pump 33 are arranged in the pump well 3. The pumping pump 31 moves the sewage stored in the pump well 3 to the outside of the sewage treatment facility 1. A pumping pipe 32 is connected to the pumping pump 31. The sewage sucked by the pump 31 is sent through the pumping pipe 32 to a settling basin or the like (not shown) for performing the next stage sewage treatment. The water supply pump 33 is arranged at a position closer to the bottom of the pump well than the above-mentioned pump 31. A water supply pipe 34 is connected to the water supply pump 33. The sewage sucked by the water supply pump 33 is sent to each nozzle or the like described later through the water supply pipe 34. The sewage sucked by the water supply pump 33 is referred to as a fluid in the following description.

FIG. 2 is a plan view of a sand basin corresponding to an embodiment of the present invention as viewed from above. In FIG. 2, the dust remover is shown by a two-dot chain line rectangle. In addition, the flow direction of sewage is indicated by a straight arrow.

As shown in FIG. 2, the sand basin 2 has a dust remover 5, a sand collecting pit 6, a bottom plane 71, a small trough 72, a connecting surface 73, and a main body between the left wall Wa and the right wall Wb. It is a pond that is roughly rectangular in plan view and is equipped with a trough 8 and a sand collecting means 9. The bottom plane 71 and the small trough 72 correspond to an example of the bottom surface. Further, the main trough 8 corresponds to an example of a groove. Hereinafter, the left side wall Wa and the right side wall Wb may be collectively referred to as a side wall W. A protruding wall 10 for supporting the dust remover 5 is provided in the central portion in the width direction of the sand basin 2 on the upstream side. The sand collecting pit 6, the bottom plane 71, the small trough 72, the connecting surface 73, and the main trough 8 are each provided at the bottom of the sand basin 2. The bottom plane 71 is formed by the surface of concrete cast on the bottom of the pond. The main trough 8 extends in the longitudinal direction from the vicinity of the upstream end of the sand basin 2, and the upstream first main trough 815 and the upstream second main trough 816 whose rear end is connected to the sand collecting pit 6 and sand settling basin. It extends in the longitudinal direction from the vicinity of the downstream end of the pond 2, and is composed of a downstream main trough 82 whose rear end is connected to the sand collecting pit 6. The upstream first main trough 815 corresponds to an example of the first groove, and the upstream second main trough 816 corresponds to an example of the second groove. The sand basin 2 discharges fluid to the bottom flat surface 71 and the small trough 72 in a state where the sewage in the sand basin 2 is drained, and collects the sand settled on the bottom flat surface 71 and the small trough 72, so-called low-pressure sand collection. It is a type of sand basin. Hereinafter, the long side direction of the sand basin 2 is referred to as a longitudinal direction, and the short side direction is referred to as a pond width direction. This longitudinal direction is also an orthogonal direction orthogonal to the pond width direction.

Buildings, pipes, etc. (not shown) may be arranged above the sand basin 2 (on the front side of the paper in FIG. 2). Then, for the purpose of supporting the building or the like, a pillar 11 may be formed adjacent to the sand basin 2. In the sand basin 2 shown in FIG. 2, a pillar 11 is formed in the vicinity of the left wall Wa. Of the left wall Wa, the portion that becomes the base of the pillar 11 is formed with a convex wall portion Wa1 that protrudes toward the center in the width direction of the pond. On the contrary, in the portion of the left side wall Wa where the pillar 11 does not exist on the left side wall Wa, it can be said that a recessed wall portion Wa2 recessed toward the outside in the pond width direction is formed. Further, in the portion connecting the convex wall portion Wa1 and the concave wall portion Wa2, an inclined wall portion Wa3 inclined with respect to the longitudinal direction and the pond width direction is formed. Since the pillar 11 does not exist in the vicinity of the right side wall Wb, the right side wall Wb is formed substantially linearly in a plan view.

The sand collecting pit 6 is arranged at a position slightly downstream of the center in the longitudinal direction of the sand basin 2. The sand collecting pit 6 is composed of a recess formed in the central portion of the sand basin 2 in the width direction. A sand pump 61 and a stirring nozzle 62 are arranged inside the sand collecting pit 6. The sand collecting pit 6 is the deepest and deepest part of the sand basin 2. The sand collecting pit 6 has a rectangular shape in a plan view. Between the side wall W and the sand collecting pit 6, there is a sand collecting pit inclined surface 6b inclined so as to gradually deepen toward the sand collecting pit 6 side in the central portion in the pond width direction.

A total of four stirring nozzles 62 are arranged near each corner of the sand collecting pit 6. The stirring nozzle 62 is for stirring the sand collected in the sand collecting pit 6. By discharging the fluid from the discharge port 62a of the stirring nozzle 62 while driving the sand-lifting pump 61, the suction efficiency of the sand collected in the sand-collecting pit 6 by the sand-lifting pump 61 can be improved. Two pit sand collecting nozzles 63 are arranged at both ends of the sand collecting pit inclined surface 6b in the pond width direction. When the water level of the sand basin 2 is lower than the predetermined value, the fluid is discharged from the discharge port 63a of the pit sand collecting nozzle 63 to collect the sand accumulated on the sand collecting pit inclined surface 6b. Can be collected in.

The bottom plane 71 includes a first bottom surface 711 formed between the left side wall Wa and the upstream first main trough 815, and a second bottom surface 712 formed between the right side wall Wb and the upstream side second main trough 816. It is composed of a third bottom surface 713 formed between the left side wall Wa and the downstream main trough 82, and a fourth bottom surface 714 formed between the right side wall Wb and the downstream side main trough 82. The bottom plane 71 and the small trough 72 are connected to the main trough 8 on the center side of the sand basin 2 in the pond width direction. The bottom plane 71 is inclined downward by about 5 degrees from the side wall W side at the outer end in the pond width direction toward the main trough 8 so that the end on the side of the main trough 8 is the deepest. On the other hand, the bottom plane 71 is formed horizontally in the longitudinal direction. The small trough 72 has a U-shaped cross section and is gutter-shaped, and extends from the vicinity of the side wall W in the pond width direction. A plurality of small troughs 72 are arranged at equal intervals in the longitudinal direction. In the present embodiment, 28 small troughs 72 are arranged on one side and the other side in the width direction of the pond with the main trough 8 interposed therebetween, for a total of 56 small troughs 72. Similar to the bottom plane 71, this small trough 72 is also inclined downward by about 5 degrees from the side wall W side toward the main trough 8 side so that the portion connected to the main trough 8 is located most on the bottom side of the pond. There is.

The upstream side first main trough 815, the upstream side second main trough 816, and the downstream side main trough 82 are grooves formed by a trough forming body which is a stainless steel plate having an arc shape with a cross section of 2/3 circle. .. However, the upstream first main trough 815, the upstream second main trough 816, and the downstream main trough 82 may be integrally formed of concrete with the bottom plane 71. The upstream first main trough 815, the upstream second main trough 816, and the downstream main trough 82 are horizontally arranged over the entire length from the vicinity of the end of the sand basin to the portion connected to the sand collecting pit 6. ing.

As shown in FIG. 2, the upstream first main trough 815 is provided on the left side wall Wa side with respect to the center in the pond width direction and extends in the longitudinal direction. Further, the second main trough 816 on the upstream side is provided on the right side wall Wb side with respect to the center in the width direction of the pond, and extends in the longitudinal direction. The upstream side first main trough 815 and the upstream side second main trough 816 both have a total length of 10 m and have the same shape. The downstream ends of the upstream first main trough 815 and the upstream second main trough 816 are connected to the sand collecting pit 6. An upstream trough first nozzle 831 having a trough first discharge port 831a is provided at an upstream end portion of the upstream side first main trough 815 (a tip portion of the upstream side first main trough 815). Further, an upstream trough second nozzle 832 having a trough second discharge port 832a is provided at an upstream end portion of the upstream side second main trough 816 (a tip portion of the upstream side second main trough 816). These trough first discharge port 831a and trough second discharge port 832a correspond to an example of the first discharge port. A first covering member 13 is arranged inside the first main trough 815 on the upstream side. Further, a second covering member 14 is arranged inside the second main trough 816 on the upstream side. The first covering member 13 and the second covering member 14 extend along the upstream side first main trough 815 and the upstream side second main trough 816, respectively. The total length of the first covering member 13 and the second covering member 14 is substantially the same as the total length of the upstream side first main trough 815 and the upstream side second main trough 816. As shown in FIG. 2, the first covering member 13 extends from upstream of the trough first discharge port 831a to slightly downstream beyond the portion of the upstream first main trough 815 connected to the sand collecting pit 6. It exists. With sewage accumulated in the upstream first main trough 815, the sand accumulated in the upstream first main trough 815 is moved to the sand collection pit 6 by discharging the fluid from the trough first discharge port 831a. Can be done. Further, the second covering member 14 extends from the upstream of the second trough discharge port 832a to a slight downstream of the second main trough 816 on the upstream side beyond the portion connected to the sand collecting pit 6. With sewage accumulated in the upstream side second main trough 816, the sand accumulated in the upstream side second main trough 816 is moved to the sand collection pit 6 by discharging the fluid from the trough second discharge port 832a. Can be done. The movement of sand in the upstream first main trough 815 and the upstream second main trough 816, and the detailed description of the first covering member 13 and the second covering member 14 will be described later.

The downstream main trough 82 extends linearly in the longitudinal direction at the center of the sand basin 2 in the width direction. The total length of the downstream main trough 82 is 5 m. The upstream end of the downstream main trough 82 is connected to the sand collecting pit 6. A downstream trough nozzle 84 having a trough third discharge port 84a is provided at the downstream end of the downstream main trough 82 (the tip portion of the downstream main trough 82). The trough third discharge port 84a also corresponds to an example of the first discharge port. A third covering member 15 is arranged inside the downstream main trough 82. The third covering member 15 extends along the downstream main trough 82. The total length of the third covering member 15 is substantially the same as the total length of the downstream main trough 82. As shown in FIG. 2, the third covering member 15 extends from the downstream side of the trough third discharge port 84a to a little upstream of the main trough 82 on the downstream side beyond the portion connected to the sand collecting pit 6. ing. With the sewage accumulated in the downstream main trough 82, the sand accumulated in the downstream main trough 82 can be moved to the sand collecting pit 6 by discharging the fluid from the trough third discharge port 84a. A detailed description of the movement of sand in the downstream main trough 82 and the third covering member 15 will be described later.

A protruding wall 10 for supporting the dust remover 5 is formed in the upstream portion of the sand basin 2 between the upstream first main trough 815 and the upstream second main trough 816. The protruding wall 10 is a concrete wall that rises up to the vicinity of the upper end of the sand basin 2. The connecting surface 73 is located between the upstream first main trough 815 and the upstream second main trough 816, and is arranged at the bottom of the pond on the downstream side of the protruding wall 10. That is, the connecting surface 73 is formed in a portion between the upstream first main trough 815 and the upstream second main trough 816, excluding the region where the protruding wall 10 is provided. The connection surface 73 includes a ridge line portion 731 extending along the longitudinal direction, a first connection surface 732 connecting the ridge line portion 731 and the upstream first main trough 815, and the ridge line portion 731 and the upstream side second main. It is composed of a second connection surface 733 that connects to the trough 816. The extending direction of the ridge line portion 731 may not be completely the same as the longitudinal direction, and may be, for example, a direction slightly inclined in the pond width direction and the vertical direction with respect to the longitudinal direction. Further, the ridge line portion 731 may meander slightly in the pond width direction and the vertical direction. That is, "extending along the longitudinal direction" is a concept including some inclination and meandering.

FIG. 3 is a cross-sectional view taken along the line XX of the sand basin shown in FIG. In FIG. 3, the dust remover is not shown.

As shown in FIG. 3, the first connecting surface 732 is an inclined surface inclined downward toward the upstream first main trough 815. Further, the second connecting surface 733 is an inclined surface inclined downward toward the upstream second main trough 816. The first connecting surface 732 and the second connecting surface 733 are composed of a concrete surface. The tilt angle of the first connecting surface 732 and the second connecting surface 733 is about 45 degrees with respect to the horizontal plane. Since the connecting surface is inclined, the sand that has settled on the connecting surface 73 can be collected in the upstream first main trough 815 or the upstream second main trough 816 without remaining on the connecting surface 73. .. If the inclination angle of the first connection surface 732 and the second connection surface 733 is 15 degrees or more, most of the sand that settles on the connection surface 73 in the sewage in the sand basin 2 is mostly the connection surface 73 due to its own weight. Sliding down. Further, if the inclination angle of the first connection surface 732 and the second connection surface 733 is set to 30 degrees or more, the sand that has settled on the connection surface 73 is more likely to slide off the connection surface 73, which is preferable. However, if the inclination angle is made too large, the thickness of the concrete constituting the connecting surface 73 in the pond width direction becomes too thin in the vicinity of the ridge line portion 731, and the ridge line portion 731 portion tends to be damaged. Therefore, the angle of the ridge line portion 731 formed by the first connection surface 732 and the second connection surface 733 is set so that the angle of the ridge line portion 731 formed by the first connection surface 732 and the second connection surface 733 is 30 degrees or more. It is preferable to do so. It should be noted that one or both of the first connection surface 732 and the second connection surface 733 may not be configured by a single plane, and may be configured by, for example, a plurality of surfaces having different inclination angles. In this case, the inclination angles of all the plurality of surfaces may be set to 15 degrees or more. Further, one of the first connection surface 732 and the second connection surface 733 may be a vertical surface and the other may be an inclined surface. However, by making each of the first connection surface 732 and the second connection surface 733 an inclined surface as in the present embodiment, sand is distributed to the upstream side first main trough 815 and the upstream side second main trough 816 and slid off. Therefore, it is preferable to make each sloped surface. Further, as in the present embodiment, by providing the ridgeline portion 731 in the central portion between the upstream side first main trough 815 and the upstream side second main trough 816, the upstream side first main trough 815 and the upstream side second main trough 815. The amount of sand that slides down the main trough 816 can be made uniform. By doing so, it is possible to prevent a large amount of sand from accumulating on one of the upstream first main trough 815 and the upstream second main trough 816. Therefore, the upstream first main trough 815 and the upstream side It is possible to prevent the sand from being unable to be transported to the sand collecting pit 6 due to the transport resistance of the sand in the second main trough 816.

4 (a) is an enlarged view showing the Z portion of FIG. 3 in an enlarged manner, and FIG. 4 (b) is a schematic perspective view showing a first covering member and an upstream trough first nozzle. In FIG. 4A, the left-right direction of the figure is the pond width direction, and the direction orthogonal to the paper surface is the longitudinal direction. Further, in FIG. 4A, hatching showing a cross section of the upstream first main trough and the first covering member is omitted.

FIG. 4A shows an upstream first main trough 815, an upstream trough first nozzle 831, and a first covering member 13. The upstream side second main trough 816, the upstream trough second nozzle 832, and the second covering member 14, and the downstream side main trough 82, the downstream trough nozzle 84, and the third covering member 15 are connected to the bottom plane 71. Alternatively, since the shape is the same except for the connection surface 73, the description thereof will be omitted. As described above, the upstream first main trough 815 of the present embodiment has a cross-sectional shape of 2/3 circle. That is, it has an arc shape centered on the trough arc center 815c, which is the center in the radial direction. However, the cross-sectional shape of the upstream first main trough 815 is not limited to the arc shape, and may be a U shape, a V shape, or the like. The first main trough 815 on the upstream side has a shape in which the upper part of a cylinder having an inner diameter of 300 mm is cut out, and is open upward over the entire length thereof. Hereinafter, this open portion may be referred to as a first trough opening 815b. A small trough 72 is connected to the first trough opening 815b, and the position of the first trough opening 815b in the height direction is the same as the position of the lower end of the small trough 72 in the height direction. The upper portion 815a of the first main trough 815 on the upstream side above the trough arc center 815c becomes narrower in the pond width direction toward the first trough opening 815b at the upper end. As a result, even if the sand soars in the upstream first main trough 815, the upper portion 815a acts as a barb, and the soared sand can be returned to the upstream first main trough 815.

The first covering member 13 has a cross-sectional shape of 5/6 circle having an opening 13a at the lower end portion. That is, it has an arc shape with the center of the covering arc 13c, which is the center in the radial direction, as the center point. The first covering member 13 is made by molding a stainless steel plate having a plate thickness of 3 mm into an arc shape having an inner diameter of 150 mm. The opening 13a is provided over the entire length of the first covering member 13. The first covering member 13 partitions the internal space of the first main trough 815 on the upstream side. The space inside the first covering member 13 becomes a transport space FS which is a space covered by the first covering member 13. Since the first covering member 13 has an arc shape in which the upper portion is closed, the sand that has settled in the sand basin 2 toward the upper portion of the first covering member 13 is the upper portion of the first covering member 13. Easy to slip off the outer surface of the. The sand that has slipped off accumulates below the first main trough 815 on the upstream side. Further, the transport space FS of the first covering member 13 below the center of the covering arc 13c becomes narrower in the pond width direction toward the lower opening 13a. The first covering member 13 is supported by a support metal fitting 131 (see FIG. 5) fixed to the concrete placed on the bottom of the sand basin 2 with a chemical anchor. The height position of the upper end of the first covering member 13 is located at substantially the same height as the first trough opening 815b. It is desirable that the height position of the upper end of the first covering member 13 is substantially the same as the height of the first trough opening 815b or lower than the first trough opening 815b. By setting this position, if the inside of the first main trough 815 on the upstream side is filled with water, the inside of the first covering member 13 can be filled with water. When the fluid is discharged into the water from the trough first discharge port 831a, the inside of the first covering member 13 is filled with water, so that a strong flow of the fluid can be created inside the first covering member 13. Further, the opening 13a of the first covering member 13 is arranged below the center 815h in the height direction of the upstream first main trough 815. With this arrangement, the opening 13a of the first covering member 13 and the sand deposited under the first main trough 815 on the upstream side can be brought close to each other. It becomes easy to suck up the sand accumulated in the first main trough 815 into the inside of the first covering member 13. Since both ends of the first covering member 13 in the extending direction are open, if the water level of the sand basin 2 is higher than the upper end position of the first covering member 13, the atmosphere may remain in the transport space FS. Instead, the transport space FS is filled with sewage. Further, although the first covering member 13 of the present embodiment has an example of an arcuate cross-sectional shape, the cross-sectional shape may be a polygonal shape, and the arcuate and the linear portion may be continuous. May be. However, it is desirable that the cross-sectional shape of the upper portion of the first covering member 13 is an inclined surface inclined downward in the width direction of the groove. By making the upper portion of the first covering member 13 an inclined surface, the sand that has settled on the upper portion of the first covering member 13 easily slides off the upper portion thereof, so that the sand in the upstream first main trough 815 is easily slipped off. It becomes easy to deposit downward.

The trough first discharge port 831a is arranged in the transport space FS in the first covering member 13. The trough first discharge port 831a has an elongated hole shape in which the tip of a pipe having an inner diameter of 80 mm is flattened from above and below. The maximum opening length of the trough first discharge port 831a in the pond width direction is 117 mm, and the maximum height in the vertical direction is 18 mm. The trough first discharge port 831a may have another shape such as a perfect circle. However, by forming the trough first discharge port 831a into a flat shape, the fluid can be discharged in a wider range than that of a perfect circle before crushing. The discharge flow rate of the fluid discharged from the trough first discharge port 831a is preferably 8 m / sec or more. If it is less than 8 m / sec, the flow velocity may be insufficient and the sand may not be moved by a predetermined distance. Further, it is desirable that the discharge pressure of the fluid discharged from the trough first discharge port 831a is 0.05 MPa or more and 0.3 MPa or less. The center of the trough first discharge port 831a coincides with the center of the covering arc 13c. The trough first discharge port 831a discharges the fluid in the longitudinal direction, which is the extending direction of the first covering member 13. As shown in FIG. 4B, the first covering member 13 extends in the fluid discharge direction so as to cover the trough first discharge port 831a and the fluid discharged from the trough first discharge port 831a. ing. Starting from the center of the trough first discharge port 831a (center of the covering arc 13c), the axis extending in the flow direction of the fluid discharged from the trough first discharge port 831a is the virtual axis VL. That is, the first covering member 13 extends so as to cover the virtual axis VL extending in the longitudinal direction from the center of the trough first discharge port 831a. The extending direction of the first covering member 13 and the discharge direction of the fluid discharged from the trough first discharge port 831a do not need to be completely matched with the longitudinal direction, but by matching them, sand can be transported more efficiently. can. Even if the discharge direction of the fluid discharged from the trough first discharge port 831a and the extending direction of the first covering member 13 are slightly different, the discharged fluid is guided by the first covering member. , The flow direction of the fluid coincides with the extending direction of the first covering member. Therefore, the virtual axis VL in this case is in the extending direction of the first covering member. However, in this case, the fluid may collide with the first covering member and the flow may be weakened. Therefore, the discharge direction of the fluid discharged from the trough first discharge port 831a and the extending direction of the first covering member 13 are made to match. Is desirable. Further, the center of the trough first discharge port 831a may be located at a position different from the center of the covering arc, for example, below the center 13c of the covering arc and above the opening 13a. However, by aligning the center of the trough first discharge port 831a with the center of the covering arc 13c, the loss of the flow of the fluid discharged from the trough first discharge port 831a can be minimized. On the other hand, by arranging the center of the trough first discharge port 831a below the center of the covering arc 13c, it is possible to increase the suction force for sucking sand into the transport space FS from the opening 13a. Therefore, it is desirable that the center of the trough first discharge port 831a is arranged between the center of the covering arc and the opening 13a of the first covering member 13.

When the fluid is discharged into the transport space FS from the trough first discharge port 831a, a fluid flow is generated in the transport space FS inside the first covering member 13. Then, a pressure difference due to the flow of fluid occurs between the transport space FS and the outside of the first covering member 13. That is, a negative pressure is generated in the transport space FS in which the fluid flow is generated. The sand deposited in the first main trough 815 on the upstream side is sucked into the transport space FS from the opening 13a by a negative pressure as shown by the arrow of the curve shown in FIG. 4 (a). Further, the fluid discharged from the trough first discharge port 831a is prevented from diffusing in the radial direction orthogonal to the longitudinal direction by the first covering member 13, so that the flow is maintained in the transport space FS over a long distance. The sucked sand is transported toward the sand collecting pit 6 side by the flow of the fluid generated in the transport space FS. In this embodiment, by forming the transport space FS by the first covering member 13, it can be utilized for transporting sand without impairing the flow of the fluid discharged from the trough first discharge port 831a. As a result, the sand accumulated in the upstream first main trough 815 can be efficiently transported toward the sand collecting pit 6. As described above, below the center of the covering arc 13c in the transport space FS, the pond width direction becomes narrower toward the lower opening 13a. By forming the width of the opening 13a in the pond width direction narrower, the sand transported in the transport space FS is less likely to leak out from the inside of the transport space FS. Further, since the fluid in the transport space FS is less likely to flow out from the transport space FS, the flow of the fluid can be maintained for a long distance, and the sand can be moved farther. Then, it becomes easy to maintain the negative pressure in the transport space FS even at a position away from the trough first discharge port 831a.

As shown in FIG. 2, two dust removers 5 are provided side by side in the width direction of the pond with the protruding wall 10 interposed therebetween in the upstream portion of the sand basin 2. In other words, one dust remover 5 is arranged between the left side wall Wa and the protruding wall 10 and one between the right side wall Wb and the protruding wall 10. These two dust removers 5 and 5 have the same configuration. The dust remover 5 is for removing contaminants (residues) mixed in the sewage that has flowed into the sand basin 2. One dust remover 5 shown on the upper side of FIG. 2 is supported by the left side wall Wa and the protruding wall 10, and the other dust remover 5 shown on the lower side of FIG. 2 is supported by the right side wall Wb. It is supported by a protruding wall 10. By arranging the two dust removers 5 and 5 side by side in the pond width direction, the width of each dust remover 5 in the pond width direction can be shortened. By shortening the width of the dust remover 5 in the pond width direction, the strength of the dust remover 5 is increased, and even if the amount of sewage flowing into the sand basin 2 and the flow velocity increase due to heavy rain or the like, the dust remover 5 is damaged. It can be suppressed from being stored.

FIG. 5 is a cross-sectional view taken along the line AA of the sand basin shown in FIG. In FIG. 5, the pillar is not shown, and the shape of the protruding wall is shown by a two-dot chain line. In addition, the flow direction of sewage is indicated by a straight arrow. The water surface WL of the sand basin varies depending on the amount of inflowing rain and sewage, but normally, the amount of rain and sewage is expected, as shown in FIG. 5, in the height direction of the sand basin 2. It is located at a medium height.

As shown in FIG. 5, the dust remover 5 has an endless chain 51, a plurality of rakes 52 attached to the endless chain 51 at intervals, and a filtration screen 53. The endless chain 51 is provided so as to stand diagonally on both sides of the sand basin 2 in the width direction, and is wound around the ground side sprocket 511 and the pond bottom side sprocket 512. The upper portion of the endless chain 51 and the above-ground sprocket 511 are arranged on the above-ground portion of the sand basin 2. When the ground-side sprocket 511 is driven in the rotation direction indicated by the arcuate arrow R by a motor (not shown) when the water surface WL is in the normal state, the endless chain 51 circulates and the rake 52 enters and exits the water. FIG. 5 shows the water surface WL in the normal state. The protruding wall 10 projects upward from the water surface WL. However, when the projecting wall 10 is formed for a purpose other than supporting the dust remover 5, the projecting wall 10 may be lower than the water surface WL. The filtration screen 53 is arranged on the downstream side of the endless chain 51. The filtration screen 53 has bars extending in the vertical direction arranged at predetermined intervals (for example, 25 mm to 75 mm) in the width direction of the pond, and blocks the passage of contaminants having a size larger than the predetermined intervals. The contaminants blocked by the filtration screen 53 are scooped up by the rake 52, and the scooped up contaminants are placed on a transportation means such as a belt conveyor (not shown) on the ground side. The lower ends of the pond bottom side sprocket 512 and the filtration screen 53 are arranged on the upstream side of the bottom plane 71 and the main trough 8. On the other hand, the upper ends of the above-ground sprocket 511 and the filtration screen 53 are located above the bottom plane 71 and the upstream portion of the main trough 8. That is, the upper portion of the endless chain 51 and the filtration screen 53 overlaps the bottom plane 71 and the main trough 8 in the longitudinal direction. Note that FIG. 5 also shows a support metal fitting 151 that supports the third covering member 15.

The sand collecting means 9 includes a first nozzle header 9a, a second nozzle header 9b, a third nozzle header 9c arranged on the left side wall Wa side of the sand sink 2, and a fourth nozzle header 9d arranged on the right side wall Wb side. , A fifth nozzle header 9e, and a sixth nozzle header 9f (see FIG. 2). In FIG. 5, the sand collecting means 9 on the left side wall Wa side is shown. Since the sand collecting means 9 on the right side wall Wb side has the same configuration, the description of the sand collecting means 9 on the right side wall Wb side will be omitted. Each of the first nozzle header 9a, the second nozzle header 9b, and the third nozzle header 9c has 10 sand collecting nozzles 91, a supply pipe 92, and a mother pipe 93. The supply pipe 92 is arranged to face the left wall Wa and extends in the longitudinal direction. The mother pipe 93 has a single pipe 931 extending above the sand basin 2 and a branch pipe 932 connected to the bottom end of the single pipe 931. The single pipe 931 and the branch pipe 932 are fixed to the left wall Wa by a fixing bracket (not shown).

As shown in FIG. 5, one end of the sand lifting pipe 64 is connected to the sand pump 61. Further, the other end of the sand raising pipe 64 is connected to the transport pipe 66 above the sand basin 2. The sand lifting pipe 64 is a pipe connecting the sand lifting pump 61 and the transport pipe 66. Further, the transport pipe 66 is a pipe extending in a substantially horizontal direction above the sand basin 2. A check valve 641 and a sluice valve 642 are installed in the sand raising pipe 64. The transport pipe 66 is supported by a suspension stand 67 provided on the ground and extends in the width direction of the pond. These sand lifting pipes 64 and transport pipes 66 will be described in detail later. The sand-lifting pump 61, the sand-lifting pipe 64, and the transport pipe 66 correspond to an example of the sand-carrying equipment.

FIG. 6 is an enlarged view showing the portion B of FIG. 5 in an enlarged manner. In FIG. 6, the flow direction of sewage is indicated by a straight arrow. A side wall is also shown in FIG. Further, FIG. 6 shows one of the six nozzle headers, but the other five nozzle headers have the same configuration as the nozzle header shown in FIG.

As shown in FIG. 6, the branch pipe 932 is connected to the single pipe 931 by a flange joint 933. The branch pipe 932 is bifurcated on the lower side of the portion connected to the single pipe 931 and the branch portion at the branch destination extends in the longitudinal direction of the sand basin 2. A supply pipe 92 to which a lap joint 934 is fixed is connected to the tip portion of the branch portion. In the present embodiment, the upstream supply pipe 921 arranged on the upstream side of the branch pipe 932 and the downstream supply pipe 923 arranged on the downstream side of the branch pipe 932 with respect to one mother pipe 93. Three supply pipes 92 of an intermediate supply pipe 922 arranged between the upstream side supply pipe 921 and the downstream side supply pipe 923 are provided. The other end of the upstream supply pipe 921 and the downstream supply pipe 923, which is opposite to one end connected to the branch pipe 932, is closed by the lid 97. Both ends of the intermediate supply pipe 922 are connected to the branch pipe 932.

Three sand collecting nozzles 91 are fixed to the upstream side supply pipe 921 and the downstream side supply pipe 923 at equal intervals, respectively. Further, four sand collecting nozzles 91 are fixed to the intermediate supply pipe 922 at equal intervals. The intervals at which a total of 10 sand collecting nozzles 91 are arranged are all evenly spaced. Further, the distance between the sand collecting nozzle 91 on the most downstream side of the first nozzle header 9a (see FIG. 2) and the sand collecting nozzle 91 on the most upstream side of the second nozzle header 9b is also set in the above-mentioned 10 sand collecting nozzles. It is the same interval as the interval. That is, the sand collecting nozzles 91 are all arranged at equal intervals in the longitudinal direction of the sand basin 2. The number of sand collecting nozzles 91 arranged in each supply pipe 92 may be appropriately determined according to factors such as the length of the supply pipe 92. A discharge port 911 is formed at the tip of each sand collecting nozzle 91. The discharge port 911 corresponds to an example of the second discharge port. Of each discharge port 911, the discharge port 911 provided in the first nozzle header 9a (see FIG. 2) and the second nozzle header 9b corresponds to an example of one side discharge port, and the fourth nozzle header 9d and the fifth. The discharge port 911 provided in the nozzle header 9e (see FIG. 2) corresponds to an example of the other side discharge port. A fluid is discharged from the discharge port 911 into the atmosphere in a state where the water level of the sand basin 2 is lowered below a predetermined value and the sand accumulated on the bottom plane 71 and the small trough 72 and the discharge port 911 are exposed to the atmosphere. By doing so, the sand accumulated on the bottom plane 71 and the small trough 72 shown in FIGS. 2 and 5 can be flowed to the main trough 8. The discharge pressure of the fluid jetted from one discharge port 911 is, for example, 0.005 MPa, preferably 0.0002 MPa or more and 0.005 MPa or less. That is, the discharge pressure of the fluid discharged from the discharge port 911 is lower than the discharge pressure of the fluid discharged from the trough first discharge port 831a (0.05 MPa or more and 0.3 MPa or less). By doing so, an inexpensive and small water supply pump 33 for supplying the fluid can be used while ensuring a flow rate at which the sand accumulated on the bottom plane 71 and the small trough 72 can flow to the main trough 8. can.

Of the supply pipe 92, the portion facing the convex wall portion Wa1 and the portion facing the concave wall portion Wa2 have different distances from the supply pipe 92 to the left side wall Wa. That is, the supply pipe 92 has a first region 92a extending from the left wall Wa with a first interval in the pond width direction and a second region 92a extending from the left wall Wa with a second interval in the pond width direction. There is a region 92b. Further, since the inclined wall portion Wa3 is formed in the portion connecting the convex wall portion Wa1 and the concave wall portion Wa2 in the sand basin 2 of the present embodiment, the supply pipe 92 has the first region and the above. There is a third region 92c, which is a region connecting the second regions. Each sand collecting nozzle 91 and its discharge port 911 are arranged so as to face the left side wall Wa, and are fixed to the supply pipe 92 side by side in the longitudinal direction. In the second nozzle header 9b shown in FIG. 6, the upstream side supply pipe 921 is arranged to face the convex wall portion Wa1. That is, the region where the upstream supply pipe 921 is located corresponds to the first region 92a. On the other hand, in the intermediate supply pipe 922, the region where the discharge port 911 located closest to the upstream side supply pipe 921 is arranged faces the inclined wall portion Wa3. That is, the region corresponds to the third region 92c. Further, in the intermediate supply pipe 922, the area where three discharge ports 911 are arranged from the downstream side supply pipe 923 side, and in the downstream side supply pipe 923, two discharge ports 911 from the intermediate supply pipe 922 side are provided. The arranged area is arranged so as to face the recessed wall portion Wa2. That is, those regions correspond to the second region 92b. Further, in the downstream side supply pipe 923, the region where the discharge port 911 on the most downstream side is arranged is arranged so as to face the inclined wall portion Wa3. That is, the region corresponds to the third region 92c. Between each of these regions, a direction changing means using a lap joint 934 is provided.

FIG. 7 (a) is a cross-sectional view for explaining a state in which one pipe provided with a lap joint is connected to the other pipe, and FIG. 7 (b) shows a lap joint by loosening a bolt. It is sectional drawing for demonstrating the state in which one provided tube becomes rotatable about the axial direction with respect to the other tube. In FIG. 7, a supply pipe is shown as one pipe and a branch pipe is shown as the other pipe, but the same configuration is used when the supply pipes are connected by providing a wrap joint.

As shown in FIGS. 7 (a) and 7 (b), a lap joint 934 is welded to the end of the supply pipe 92. The lap joint 934 is composed of a small diameter portion 934a welded to the supply pipe 92 and a large diameter portion 934b arranged on the branch pipe 932 side. The outer diameter of the small diameter portion 934a is formed to be the same as the outer diameter of the supply pipe 92. A free flange 935 is arranged on the outer periphery of the lap joint 934. The free flange 935 has a ring shape in which the inner diameter is slightly larger than the outer diameter of the lap joint 934. The free flange 935 is formed with eight free flange through holes 935a into which bolts 95 are inserted evenly in the circumferential direction. The free flange 935 is coupled to the lap joint 934 so as to be rotatable and axially movable with respect to the lap joint 934. A fixed flange 9322 is welded to the outer diameter portion of the tip of the branch pipe 932. The fixed flange 9322 is formed with eight fixed flange through holes 9322a into which bolts 95 are inserted, similarly to the free flange 935. A ring-shaped packing 94 is arranged between the lap joint 934 and the fixed flange 9322. The packing 94 is for preventing the fluid passing through the inside of the supply pipe 92 and the branch pipe 932 from leaking in the state where the supply pipe 92 and the branch pipe 932 are joined.

The bolt 95 is inserted into the fixed flange through hole 9322a of the fixed flange 9322 and the free flange through hole 935a of the free flange 935. In the state where the bolt 95 and the nut 96 are tightened, the lap joint 934 is sandwiched by the fixed flange 9322 and the free flange 935 together with the packing 94 as in the supply pipe 92 shown in FIG. 7A, so that the branch pipe is formed. The supply pipe 92 is fixed to 932. On the other hand, when the bolt 95 is loosened, the supply pipe 92 becomes rotatable about the axial direction of the branch pipe 932 as shown in the supply pipe 92 shown in FIG. 7 (b). That is, in the present embodiment, since the mother pipe 93 (see FIG. 5) and the supply pipe 92 are connected by using the lap joint 934 and the free flange 935, the supply pipe 92 is centered on the axial direction thereof. It is configured to be rotatable steplessly with respect to the mother tube 93. Even if another loose flange or the like is used instead of the lap joint 934, the supply pipe 92 can be rotatably connected to the mother pipe 93 steplessly.

Further, as shown in FIG. 6, between the discharge port 911 arranged in the first region 92a and the discharge port 911 arranged in the third region 92c, and the discharge ports 911 and the third outlet arranged in the second region 92b. Wrap joints 934 are arranged between the discharge ports 911 arranged in the region 92c, respectively. Therefore, the discharge ports 911 arranged in the first region 92a, the second region 92b, and the third region 92c are configured to be independently rotatable about the axial direction of the supply pipe 92 in a stepless manner. With this configuration, the discharge direction of the fluid at the discharge port 911 in each region can be set according to the distance from the supply pipe 92 to the left wall Wa. The lap joint 934 arranged between the discharge port 911 arranged in the first region 92a and the discharge port 911 arranged in the third region 92c corresponds to an example of the first direction changing means. Further, the lap joint 934 arranged between the discharge port 911 arranged in the second region 92b and the discharge port 911 arranged in the third region 92c corresponds to an example of the second direction changing means. Further, among the supply pipes 92 shown in FIG. 6, in the first region 92a, the discharge directions of the fluids in the three discharge ports 911 arranged in the first region 92a can be changed collectively, so that the first region 92a can be changed. The discharge direction in can be easily adjusted. Of the supply pipes 92 shown in FIG. 6, in the second region 92b, the three discharge ports 911 arranged in the intermediate supply pipe 922 can be changed collectively, and the two discharge ports arranged in the downstream supply pipe 923 can be changed together. Since the outlets 911 can be changed collectively, the discharge direction in the second region 92b can be easily adjusted. That is, the lap joint 934 in the case where the discharge directions of the plurality of discharge ports 911 can be changed collectively corresponds to an example of the batch direction changing means. If the longitudinal direction of the third region 92c is short and the discharge port 911 does not exist in the third region 92c, or if the third region 92c does not exist, a wrap is made between the first region 92a and the second region 92b. The joint 934 may be arranged.

FIG. 8A is a sectional view taken along the line CC of FIG. In FIG. 8 (a), the side wall and the bottom plane are also shown.

As described above, the left side wall Wa has a convex wall portion Wa1 and a concave wall portion Wa2. In FIG. 8A, the convex wall portion Wa1 is shown by a solid line, and the concave wall portion Wa2 is shown by a two-dot chain line. In the discharge port 911 shown by the solid line in FIG. 8A, the discharge direction of the fluid is directed toward the center side in the pond width direction rather than the direction directly downward from the center of the supply pipe 92 (vertical direction). In this discharge port 911, the angle θ1 for discharging the fluid with respect to the bottom plane 71 is set to about 50 degrees. By setting the angle θ1 to about 50 degrees, the fluid that has reached the bottom plane 71 can be divided into a direction toward the main trough 8 and a direction toward the convex wall portion Wa1. This angle θ1 may be any angle as long as it is an angle at which the discharged fluid is diverted in the direction toward the main trough 8 and the direction toward the convex wall portion Wa1. Specifically, the angle θ1 is 30 degrees or more and 60 degrees or less with respect to the bottom plane 71. All you need is. By setting this angle, when the supply pipe 92 and the left side wall Wa are close to each other as in the convex wall portion Wa1, that is, in the first region 92a (see FIG. 6), the bottom between the supply pipe 92 and the left side wall Wa. The separated fluid also reaches the sand deposited on the plane 71, and the sand can be flown. Further, since the discharge direction of the fluid is oriented toward the main trough 8 side in the center of the pond width direction rather than the vertical direction of the supply pipe 92, the momentum of the fluid flowing toward the main trough 8 side is higher than the momentum of the fluid flowing toward the left wall Wa side. Becomes stronger. Due to the momentum of this fluid, the sand deposited on the bottom plane 71 between the supply pipe 92 and the main trough 8 can be efficiently flowed toward the main trough 8.

On the other hand, in the recessed wall portion Wa2 portion shown by the alternate long and short dash line in FIG. 8A, the supply pipe 92 and the left side wall Wa are separated from each other. Therefore, in the discharge direction of the discharge port 911 shown by the solid line, even if the discharged fluid flows, it does not reach the vicinity of the recessed wall portion Wa2, or even if it reaches, only a very small amount of fluid reaches. If the amount of fluid reaching the vicinity of the recessed wall portion Wa2 is small, among the sand deposited between the supply pipe 92 and the recessed wall portion Wa2, the sand in the vicinity of the recessed wall portion Wa2 cannot be sufficiently flowed.

In the present embodiment, since the supply pipe 92 is configured to be rotatable around its axis direction, the discharge direction of the fluid from the sand collecting nozzle 91 can be freely changed. In FIG. 8A, a sand collecting nozzle 91 whose discharge direction of the fluid discharged from the discharge port 911 is adjusted corresponding to the position of the recessed wall portion Wa2 is shown by a two-dot chain line. In the sand collecting nozzle 91 indicated by the two-dot chain line, the discharge direction of the fluid discharged from the discharge port 911 is directed to the outside in the pond width direction from the direction directly downward from the center of the supply pipe 92 (vertical direction). There is. By adjusting the discharge direction of the fluid discharged from the discharge port 911 according to the distance from the supply pipe 92 to the left side wall Wa, the supply pipe 92 and the left side wall Wa as shown in the second region 92b (see FIG. 6). Even if they are separated from each other, the sand accumulated in the vicinity of the left wall Wa can be sufficiently washed away. In this embodiment, since the mother pipe 93 and the supply pipe 92 or the supply pipes 92 are connected to each other by using the wrap joint 934 and the free flange 935, the connected supply pipe 92 is not centered on the axis. It can be rotated in stages. Since it can rotate steplessly, the supply pipe 92 (third region 92c) located at a position facing the inclined wall portion Wa3 (see FIG. 2) between the convex wall portion Wa1 and the concave wall portion Wa2 has FIG. 8 (a). It is also possible to set the discharge direction of the fluid in the intermediate direction between the discharge direction of the sand collecting nozzle 91 shown by the solid line and the discharge direction of the sand collecting nozzle 91 shown by the alternate long and short dash line.

Further, in the present embodiment, since the mother pipe 93 is provided with the branch pipe 932, a total of three pipes of the upstream side supply pipe 921, the intermediate supply pipe 922, and the downstream side supply pipe 923 are provided for one mother pipe 93. The supply pipes 92 of the above are connected side by side in the longitudinal direction of the sand pond 2. On the other hand, when there is no branch pipe 932 and the supply pipe 92 is connected to the single pipe 931, there are at most two supply pipes 92 in the longitudinal direction of the sand basin 2 with respect to one mother pipe 93. can not connect. That is, there are two supply pipes 92 extending from the tip of the mother pipe 93 to the upstream side of the sand basin 2 and extending to the downstream side. The discharge direction of the fluid discharged from the discharge port 911 can be set for each supply pipe 92. Therefore, as compared with the case where there is no branch pipe 932, when the branch pipe 932 is provided, the discharge direction of the fluid discharged from the discharge port 911 can be adjusted at many points in the longitudinal direction of the sand basin 2. The shape of the side wall W makes it possible to respond flexibly.

FIG. 8B is a cross-sectional view similar to FIG. 8A for explaining the change of the discharge direction by the sand collecting nozzle. The side wall and bottom plane are also shown in FIG. 8 (b).

As shown in FIG. 8B, the sand collecting nozzle 91 is bent at the intermediate portion, and in the state shown by the solid line, it is formed in an inverted shape when viewed in the longitudinal direction. Since it is formed in an inverted shape, when the sand collecting nozzle 91 shown by the solid line is rotated 180 degrees around the axis L of the attachment portion with the supply pipe 92, it is as shown by the two-dot chain line. , The discharge direction of the fluid can be changed from the center side in the pond width direction to the outside in the pond width direction. By forming the sand collecting nozzle 91 in an inverted shape and configuring the connection portion between the sand collecting nozzle 91 and the supply pipe 92 to be rotatable, it is possible to change the discharge direction of the fluid for each discharge port 911. become. That is, the shape of the sand collecting nozzle 91 and the configuration in which the sand collecting nozzle 91 is rotatable with respect to the supply pipe 92 in the present embodiment correspond to an example of the individual direction changing means.

FIG. 9 is a schematic cross-sectional view of four sewage treatment facilities cut in the pond width direction at the sand collecting pit portion and viewed in the longitudinal direction. In FIG. 9, the sand collecting pit, the sand raising pipe, and the transport pipe are shown, and the background is omitted. Further, FIG. 10 is a skeleton diagram showing a sand-lifting pump, a sand-lifting pipe, a transport pipe, and a sand-sinking separator.

As described above, four sewage treatment facilities 1 described so far are provided in parallel with respect to the flow direction of sewage. Therefore, as shown in FIG. 9, four sand basins 2 are also provided side by side in the width direction of the pond. The sand pump 61 and the sand pipe 64 are provided in the sand basin 2, respectively. The sand raising pipe 64 extends from the bottom of the sand basin 2 to the upper part of the sand basin 2. The transport pipe 66 is supported by a suspension base 67 and is laid in a straight line substantially horizontally so as to straddle the upper part of the three sand basins 2 on the right side in FIG. That is, the transport pipe 66 extends in the direction of intersecting with the sand lifting pipe 64. The transport pipe 66 may extend in a direction inclined with respect to the horizontal direction. One end 66a of the transport pipe 66 is composed of a lid for closing the transport pipe 66, which is arranged above the left wall Wa of the leftmost sand basin 2 in FIG. Further, as shown in FIG. 10, the other end of the transport pipe 66 is connected to a sand settling basin SS placed on the ground apart from the sand basin 2. The sand that has passed upward in the sand raising pipe 64 is sent into the transport pipe 66 and is conveyed in the transport pipe 66 from the left side to the right side in FIG.

11 (a) is an enlarged view showing an enlarged portion E of FIG. 9, and FIG. 11 (b) is an enlarged view of FIG. 11 (a) seen from the upstream side in the transport direction of the transport pipe. In FIG. 11A, the left-right direction is the pond width direction, and the direction orthogonal to the paper surface is the longitudinal direction of the sand basin. Further, in FIG. 11B, the left-right direction in the figure is the longitudinal direction of the sand basin, and the direction orthogonal to the paper surface is the pond width direction. In FIG. 11, the suspension base is not shown.

As shown in FIGS. 11A and 11B, the sand-lifting pipe 64 has a main sand-lifting portion 64a extending upward from the sand-lifting pump 61 beyond the transport pipe 66, and the central axis of the pipe is in the horizontal direction. It has a horizontal portion 64b facing toward the surface, an inclined portion 64c in which the central axis of the pipe is inclined in the vertical direction with respect to the horizontal direction, and a first elbow 64e and a second elbow 64f. The first elbow 64e and the second elbow 64f are both L-shaped identical parts bent 90 degrees. Here, since the elbow bent by 90 degrees is distributed on the market as a general-purpose part, the sand lifting pipe 64 can be constructed at low cost by adopting the elbow bent by 90 degrees. The main sand raising portion 64a is provided with a check valve 641 and a sluice valve 642. When the check valve 641 is driving the sand pump 61 (see FIG. 9), the valve automatically opens due to the flow of sand and sewage pumped by the sand pump 61, and the sand pump 61 stops. When it is, it is a valve that is automatically closed by the flow of sewage trying to return to the sand pump 61 side. A sluice valve 642 is arranged on the check valve 641. This sluice valve 642 is a valve that can manually control the flow of sand and sewage in the main sand raising portion 64a. The sluice valve 642 is normally open and allows sand and sewage flow. When removing the check valve 641 for inspection of the sand basin 2, the sewage valve 642 is switched to the closed state and the flow of sand and sewage is stopped to prevent the sewage above the sewage valve 642 from flowing back. can.

As shown in FIG. 9, one end of the main sand lifting portion 64a is connected to the sand lifting pump 61. The main sand-lifting portion 64a has a portion extending in the horizontal direction, a portion extending in the vertical direction, and a portion inclined with respect to the vertical direction. However, the whole of the main sand-lifting portion 64a may be inclined with respect to the vertical direction, or the whole may extend in the vertical direction. The check valve 641 and the sluice valve 642 are arranged at the other end side portion of the main sand raising portion 64a. As shown in FIGS. 11A and 11B, the other end side of the main sand raising portion 64a with respect to the check valve 641 extends in the vertical direction. The first elbow 64e is integrated with the main sand-lifting portion 64a by being welded to the other end of the main sand-lifting portion 64a. The first elbow 64e and the horizontal portion 64b are connected by a flange joint. The second elbow 64f is integrated with the horizontal portion 64b by being welded to the horizontal portion 64b. The second elbow 64f and the inclined portion 64c are connected by a flange joint. As shown in FIG. 11A, the inclined portion 64c is connected to the upper portion of the transport pipe 66 by welding in a state of being inclined upward from the horizontal at an angle of θ2. The upper portion of the transport pipe 66 as used herein refers to a portion above the central axis 66c of the transport pipe 66. In the transport pipe 66, the opening formed in the portion to which the sand lifting pipe 64 is connected becomes the pipe connecting portion 66b. This pipe connecting portion 66b corresponds to an example of a connecting portion with the sand raising pipe 64 in the transport pipe 66. The horizontal portion 64b is connected to the first elbow 64e by adjusting the angle around the central axis of the horizontal portion 64b so that the central axis of the flange portion 64f1 of the second elbow 64f coincides with θ2.

The sand and sewage sucked up by the sand lifting pump 61 (see FIG. 9) are sent into the transport pipe 66 via the sand lifting pipe 64. The sand and sewage sent into the transport pipe 66 are transported in the direction of the arrow G shown in FIG. 11 (a). When the sand lifting pump 61 is stopped, the check valve 641 closes, and the sand in the main sand lifting portion 64a above the check valve 641 falls and accumulates on the check valve 641. However, since the volume of the main sand lifting portion 64a in the pipe above the check valve 641 is very small, the amount of sand in the pipe is extremely small. Therefore, even if the sand is deposited on the check valve 641, it has almost no effect on the opening and closing of the check valve 641. On the other hand, since the sand-lifting pipe 64 (inclined portion 64c) and the pipe connecting portion 66b of the transport pipe 66 are located on the upper portion of the transport pipe 66, it is difficult for the sand in the transport pipe 66 to enter the sand-lifting pipe 64. This is because the sand in the transport pipe 66 is difficult to move to the upper portion of the transport pipe 66 due to its own weight. Further, even if the sand in the transport pipe 66 gets into the sand lifting pipe 64, the horizontal portion 64b and the like are arranged above the pipe connecting portion 66b, so that the sand forms the inclined portion 64c. It does not climb to reach the horizontal portion 64b. That is, since the sand is blocked by the inclined portion 64c, it is possible to prevent the sand that has entered the sand lifting pipe 64 from the transport pipe 66 from accumulating on the check valve 641. Therefore, it is possible to reliably prevent the check valve 641 from being unable to open due to the accumulation of a large amount of sand on the check valve 641. In this embodiment, an example is shown in which the horizontal portion 64b or the like is arranged above the pipe connecting portion 66b. However, if there is a portion of the sand raising pipe 64 between the check valve 641 and the transport pipe 66 that is arranged above the pipe connecting portion 66b, the above-mentioned effect of blocking the sand can be obtained. Hereinafter, the portion arranged above this may be referred to as an upward arrangement portion. The term "arranged upward" as used herein means that the lowermost portion of the internal space of the sand raising pipe 64 in the upper arrangement portion is located at a position higher than the lowermost portion in the pipe connecting portion 66b. However, it is more desirable that the entire internal space of the sand lifting pipe 64 in the upper arrangement portion is above the uppermost portion in the pipe connecting portion 66b. According to this aspect, the effect of blocking sand becomes more certain.

The angle θ2 formed by the transport pipe 66 and the inclined portion 64c in the present embodiment is 45 degrees. By setting θ2 to be larger than 0 degrees and less than 90 degrees, the sand raising pipe 64 (inclined portion 64c) can be connected to the transport pipe 66 while gradually approaching the transport pipe 66 toward the transport direction of the transport pipe 66. can. As a result, there is an effect that the sand sucked up in the other sand basin 2 and transported in the transport pipe 66 from the opposite transport direction side of the pipe connection portion 66b can be suppressed from entering the sand lift pipe 64. be. Further, the sand moving from the sand raising pipe 64 into the transport pipe 66 is sent into the transport pipe 66 in a direction close to the transport direction and is conveyed as it is along with the flow of sewage generated in the transport pipe 66. Since it moves in the direction, it also has an effect of suppressing the return to the inside of the sand raising pipe 64. Due to these effects, it is possible to prevent a large amount of sand from accumulating on the check valve 641 and preventing the check valve 641 from being opened. In addition, since the sewage in the sand raising pipe 64 is sent into the transport pipe 66 in a direction close to the transport direction of the transport pipe 66, the fed sewage promotes the flow of the sewage in the transport pipe 66 in the transport direction. It also has the effect of being able to do things. However, θ2 is preferably 30 degrees or more and 60 degrees or less. If the temperature is less than 30 degrees, it becomes difficult to connect the sand lifting pipe 64 and the transport pipe 66. Further, if the temperature exceeds 60 degrees, the above-mentioned effect is halved.

FIG. 12 is a water supply system diagram in a sewage treatment facility.

As shown in FIG. 12, the water supply pump 33 uses the water in the pump well 3 as a stirring nozzle 62, a pit sand collecting nozzle 63, an upstream trough first nozzle 831, an upstream trough second nozzle 832, and a downstream trough nozzle 84. And selectively supply to the sand collecting means 9. The water supply pipe 34 connected to the water supply pump 33 has a supply switching valve Va for switching whether or not to supply the fluid to each of the above-mentioned nozzles and the sand collecting means 9, and a pump well for the fluid sucked up by the water supply pump. A relief switching valve Vb for switching whether or not to return to 3 is provided. A stirring switching valve Vc for switching whether or not to supply a fluid to the stirring nozzle 62 is provided in the conduit between the supply switching valve Va and the stirring nozzle 62. A pit sand collecting switching valve Vd for switching whether or not to supply a fluid to the pit sand collecting nozzle 63 is provided in the pipeline between the supply switching valve Va and the pit sand collecting nozzle 63. The pipeline between the supply switching valve Va and the upstream trough first nozzle 831 is provided with an upstream trough first switching valve Ve1 for switching whether or not to supply a fluid to the upstream trough first nozzle 831. An upstream trough second switching valve Ve2 for switching whether or not to supply a fluid to the upstream trough second nozzle 832 is provided in the pipeline between the supply switching valve Va and the upstream trough second nozzle 832. A downstream trough switching valve Vf for switching whether or not to supply a fluid to the downstream trough nozzle 84 is provided in the pipeline between the supply switching valve Va and the downstream trough nozzle 84. Further, in each pipeline between the supply switching valve Va and each nozzle header 9a, 9b, 9c, 9d, 9e, 9f of the sand collecting means 9, each nozzle header 9a, 9b, 9c, 9d, 9e, 9f is used. Sand collecting switching valves Vg1, Vg2, Vg3, Vg4, Vg5, and Vg6 for switching whether or not to supply a fluid are provided, respectively. These switching valves are composed of solenoid valves, and the opening and closing of the valves is controlled by a control device (not shown).

FIG. 13 is an explanatory diagram showing the water level of the sand basin and the water level sensor.

As shown in FIG. 13, a water level sensor 99 is arranged in the sand collecting pit 6 of the sand basin 2. In this water level sensor 99, the first high water level HHWL in which the water level of the sand basin 2 is above the bottom plane 71 and the upper end positions 13b (mainly) of the covering members 13, 14, 15 below the first high water level HHWL. The second high water level THWL above the upper end 8b of the trough 8, that is, the opening of the main trough 8, and the lower end 72b of the small trough 72), and the covering members 13, 14 respectively. , The first low water level TLWL near the upper end position 13b of 15, the first intermediate water level TMWL between the second high water level THWL and the first low water level TLWL, and the main below the upper end 8b of the main trough 8. The third high water level HWL above the lower end 8a of the trough 8, the second low water level LWL below the sand collection pit 6, and the second between the third high water level HWL and the second low water level LWL. It detects and outputs the intermediate water level MWL and the interlock water level LLWL even lower than the second low water level LWL.

FIG. 14 is a flowchart showing the flow of sand removal operation in a sewage treatment facility.

The operation of the sewage treatment facility 1 having the above configuration will be described with reference to FIGS. 1, 2, 14, and the like. The sewage treatment facility 1 performs an operation of removing the accumulated sand at a predetermined time when sand is accumulated to some extent on the bottom of the sand basin 2. When the predetermined time is reached, the sand removal operation is executed one by one for all four sewage treatment facilities 1 in order. This predetermined time may be regular, for example, once a month, or may be when the total flow rate of sewage flowing into or discharged from the sand basin 2 reaches a certain amount. In the sand removal operation, first, the inflow gate 42 of the dam device 4 shown in FIG. 1 is driven to block the inflow port 411 and block the inflow of sewage into the sand basin 2 (step S1). Next, the pump 31 is driven to lower the water level of the sand basin 2. When the water level of the pump well 3 drops to a predetermined value, the pump 31 is stopped (step S2). Then, the water supply pump 33 is driven for about several minutes, and the fluid is discharged from the stirring nozzle 62 shown in FIG. After the water supply pump is stopped, the sand lifting pump 61 is driven. At this time, the sand accumulated on the check valve 641 for a long period of time between the previous sand removal operation and the current sand removal operation is solidified and becomes a state close to solid, and the check valve 641 Sometimes couldn't be opened. However, in the present embodiment, since only a very small amount of sand is deposited on the check valve 641, the check valve 641 cannot be opened. When the water level of the sand basin 2 drops to the second high water level THWL (see FIG. 13), the water supply pump 33 is driven again to discharge the fluid from the stirring nozzle 62 shown in FIG. Then, the drive of the sand pump 61 is set to the operation mode A described below (step S3). The sand lifting pump 61 operates in either the operation mode A or the operation mode B. In the operation mode A, the drive is stopped according to the output indicating the first low water level TLWL (see FIG. 13) from the water level sensor 99, and the drive is restarted according to the output indicating the second high water level THWL (see FIG. 13). Control is automatically executed. This operation mode A is a mode in which the water level is maintained above the upper end positions 13b of the covering members 13, 14, and 15. Therefore, in the operation mode A, the covering members 13, 14, 15, the trough first discharge port 831a, the trough second discharge port 832a, and the trough third discharge port 84a are submerged in water. In the operation mode B, the drive of the sand lifting pump 61 is stopped in response to the output indicating the second low water level LWL (see FIG. 13) from the water level sensor 99, and the output indicating the third high water level HWL (see FIG. 13) is set. The control to restart the drive is automatically executed accordingly. This operation mode B is a mode in which the water level is maintained below the lower end 72b of the small trough 72. Therefore, the bottom plane 71, the small trough 72, the sand deposited on them, and the sand collecting means 9 are exposed to the atmosphere. On the other hand, the water supply pump 33 shown in FIG. 1 continues to be driven until the sand removal operation is completed. The sand conveyed to the sand collecting pit 6 is carried to the sand settling basin SS (see FIG. 10) outside the sand basin 2 by the sand basin pump 61 while the sand unloading pump 61 is driving. The sand lifting pump 61 repeatedly drives and stops even during this sand removal operation. In the present embodiment, since a large amount of sand does not accumulate on the check valve 641 during the stoppage, the check valve 641 cannot be opened when the drive is restarted. When the water level sensor 99 detects that the first high water level HHWL or the interlock water level LLWL (see FIG. 13), it is considered that some abnormality has occurred, so an alert is displayed and the sewage treatment facility 1 displays an alert. Stop the sand removal operation.

After that, fluid was discharged from the stirring nozzle 62, the upstream trough first nozzle 831, and the upstream trough second nozzle 832 shown in FIG. 2 for a certain period of time, and sand accumulated on the upstream first main trough 815 and the upstream second main trough 816. To the sand collecting pit 6 (step S4). In this step S4, the fluid may be discharged from one of the upstream trough first nozzle 831 and the upstream trough second nozzle 832 for a certain period of time, and then discharged from the other for a certain period of time. When the discharge of the fluid from the stirring nozzle 62, the upstream trough first nozzle 831 and the upstream trough second nozzle 832 is stopped, the sand lifting pump 61 is switched to the operation mode B (step S5). Then, when it is detected that the water level is equal to or lower than the third high water level HWL, the fluid is discharged from the discharge port 911 (see FIG. 6) provided in the fifth nozzle header 9e. By this discharge, the sand deposited on the bottom plane 71 and the small trough 72 between the right side wall Wb near the fifth nozzle header 9e and the upstream side second main trough 816 is deposited on the upstream side second main trough. It can be flushed to 816. After a predetermined time for allowing the sand to flow sufficiently has elapsed, the sand pump 61 is switched to the operation mode A while continuing the fluid discharge from the discharge port 911 provided in the fifth nozzle header 9e. After that, when it is detected that the water level is equal to or higher than the first intermediate water level TMWL, the discharge of the fluid from the discharge port 911 provided in the fifth nozzle header 9e is stopped (step S6). Then, the fluid is discharged from the stirring nozzle 62 and the upstream trough second nozzle 832 for a certain period of time, and the sand flowed into the upstream second main trough 816 is sent to the sand collecting pit 6 (step S7). When the discharge of the fluid from the stirring nozzle 62 and the upstream trough second nozzle 832 is stopped, the sand lifting pump 61 is switched to the operation mode B (step S8). Then, when it is detected that the water level is equal to or lower than the third high water level HWL, the fluid is discharged from the discharge port 911 provided in the second nozzle header 9b. After a predetermined time has elapsed so that the sand accumulated on the bottom plane 71 and the small trough 72 between the left side wall Wa near the second nozzle header 9b and the upstream first main trough 815 can be sufficiently drained, the second nozzle header 9b is arranged. 2 The sand pump 61 is switched to the operation mode A while continuing the fluid discharge from the discharge port 911 provided in the nozzle header 9b. After that, when it is detected that the water level is equal to or higher than the first intermediate water level TMWL, the discharge of the fluid from the discharge port 911 provided in the second nozzle header 9b is stopped (step S9). Among them, the discharge port 911 near the recessed wall portion Wa2 and the inclined wall portion Wa3 has a fluid discharge direction such that a certain amount of fluid reaches the left side wall Wa according to the distance from the supply pipe 92 to the left side wall Wa. It has been adjusted. Therefore, all the sand deposited on the bottom plane 71 and the small trough 72 between the left wall Wa near the second nozzle header 9b and the upstream first main trough 815 is collected from the upstream first main trough. It can flow up to 815. After stopping the discharge of the fluid from the discharge port 911 provided in the second nozzle header 9b, the fluid is discharged from the stirring nozzle 62 and the upstream trough first nozzle 831 for a certain period of time and is flowed to the upstream first main trough 815. The collected sand is sent to the sand collecting pit 6 (step S10). When the discharge of the fluid from the stirring nozzle 62 and the upstream trough second nozzle 832 is stopped, the sand lifting pump 61 is switched to the operation mode B (step S11). After that, as in the operation of steps S6 to S10 described above, the fluid is discharged from the discharge port 911 provided in the fourth nozzle header 9d, the operation mode A is switched to after a predetermined time has elapsed (step S12), and the stirring nozzle is used. Discharge of fluid from 62 and the upstream trough second nozzle 832 (step S13), switching to operation mode B (step S14), discharge of fluid from the discharge port 911 provided in the first nozzle header 9a, and elapse of a predetermined time. By switching to the operation mode A later (step S15) and discharging the fluid from the stirring nozzle 62 and the upstream trough first nozzle 831 (step S16) in this order, the bottom of the pond on the upstream side of the sand collecting pit 6 is reached. All the accumulated sand is carried out of the sand pond 2. The order in which the fluid is discharged from the nozzle headers 9a, 9b, 9d, and 9e may be arbitrary. However, when the sand accumulated on the side far from the sand collecting pit 6 is flowed first, the sand accumulated on the side near the sand collecting pit 6 collapses into the main trough 8 together with the sand to be flowed, and the sand is contained in the main trough. May become difficult to send the sand in the main trough 8 to the sand collecting pit 6. Therefore, after the fluid is discharged from the second nozzle header 9b and the fifth nozzle header 9e on the side close to the sand collecting pit 6, the fluid is discharged from the first nozzle header 9a and the fourth nozzle header 9d on the side far from the sand collecting pit 6. It is desirable to discharge.

After removing the sand accumulated on the upstream side by the above operation, the fluid is discharged from the stirring nozzle 62 and the nozzle for downstream trough 84 for a certain period of time, and the sand accumulated on the downstream main trough 82 is poured into the sand collecting pit 6 (step). S17). When the discharge of the fluid from the stirring nozzle 62 and the downstream trough nozzle 84 is stopped, the sand lifting pump 61 is switched to the operation mode B (step S18). Then, when it is detected that the water level is equal to or lower than the third high water level HWL, the fluid is discharged from the discharge port 911 provided in the sixth nozzle header 9f. After a predetermined time has elapsed so that the sand accumulated on the bottom plane 71 between the downstream main trough 82 and the small trough 72 can sufficiently flow from the right side wall Wb near the sixth nozzle header 9f, the sixth nozzle While continuing the fluid discharge from the discharge port 911 provided in the header 9f, the sand lifting pump 61 is switched to the operation mode A. After that, when it is detected that the water level is equal to or higher than the first intermediate water level TMWL, the discharge of the fluid from the discharge port 911 provided in the sixth nozzle header 9f is stopped (step S19). Then, the fluid is discharged from the stirring nozzle 62 and the downstream main trough 82 for a certain period of time, and the sand flowed in the downstream main trough 82 is sent to the sand collecting pit 6 (step S20). When the discharge of the fluid from the stirring nozzle 62 and the downstream main trough 82 is stopped, the sand lifting pump 61 is switched to the operation mode B (step S21). Then, as in the operation of steps S19 and S20 described above, the fluid is discharged from the discharge port 911 provided with the third nozzle header 9c, the operation mode A is switched to after a predetermined time has elapsed (step S22), and the stirring nozzle 62. And by operating the fluid discharge from the downstream trough nozzle 84 (step S23) in this order, all the sand deposited on the bottom of the pond on the downstream side of the sand collecting pit 6 is carried out to the outside of the sand basin 2. Finally, by discharging the fluid from the pit sand collecting nozzle 63, the sand accumulated on the sand collecting pit inclined surface 6b is flowed to the sand collecting pit 6 (step S24). When all of these operations are completed, the water supply pump 33 is stopped, and the sand lifting pump 61 is also stopped after a predetermined time has elapsed. This series of sand removal operations is sequentially executed for each of the four sewage treatment facilities 1.

In this sand removal operation, when the sand lifting pump 61 is switched from the operation mode A to the operation mode B, the fluid is supplied to the sand basin 2 until it is detected that the water level is equal to or lower than the third high water level HWL. It is stopped. As a result, the rate of decrease in water level can be accelerated. At that time, in order to stop the supply of the fluid to the sand basin 2, the supply switching valve Va shown in FIG. 12 is closed, the relief switching valve Vb is opened, and the fluid pumped up by the water supply pump 33 is returned to the pump well 3. There is. By doing so, it is possible to stop the supply of the fluid to the sand basin 2 while continuing to drive the water supply pump 33. In the sand removing operation described so far, each of steps S4, S7, S10, S13, S16, S17, S20, and S23 corresponds to an example of the underwater discharge process. Further, each of steps S6, S9, S12, S15, S19, and S22 corresponds to an example of the atmospheric discharge process. That is, in the present embodiment, a set of sand collecting processes (steps S6 and S7, S9 and S10, S12 and S13, S15 and S16, S19 and S20,) is performed by executing the underwater discharge process after executing the atmospheric discharge process. As each combination of S22 and S23), the sand collecting process is executed a plurality of times. Further, the underwater discharge step (step S4) is executed before the first sand collection treatment (steps S6 and S7) is performed. If sand remains in the main trough 8 during the atmospheric discharge process, the sand washed into the main trough 8 by the atmospheric discharge process will be added to the remaining sand, resulting in a large amount of sand remaining in the main trough 8. There is a risk of sand accumulating. Further, during the atmospheric discharge process, the inside of the main trough 8 may be filled with sand, and the overflowing sand may remain on the bottom plane 71. In the present embodiment, the sand flowed from the bottom plane 71 to the main trough 8 is transported to the sand collecting pit 6 in a set of sand collecting treatments, so that the sand remains in the main trough 8. There is no. Further, since the underwater discharge step (steps S4 and S17) is executed before the first sand collection treatment (combinations of steps S6 and S7 and S19 and S20) is performed, the first sand collection treatment is also performed. No sand remains in the main trough 8.

In this embodiment, when the above-mentioned sand removal operation is being performed, the amount of fluid pumped by the sand pump 61 is set to be slightly larger than the amount of fluid pumped by the water supply pump 33. ing. Therefore, the sand lifting pump 61 repeats stopping and restarting a plurality of times while the removal operation is being executed. However, when the sand lifting pump 61 is repeatedly driven and stopped, the pump life is shortened due to the inrush current at the start of driving. As a countermeasure, the change in the water level in the sand removal operation may be minimized by bringing the pumping capacity of the water supply pump 33 and the fluid pumping capacity of the sand pump 61 close to each other. Further, when the water level sensor 99 detects that the water level sensor 99 has dropped to the first intermediate water level TMWL in the operation mode A and the second intermediate water level MWL in the operation mode B, in addition to the nozzle discharging the fluid at that time, another nozzle. An additional fluid may be discharged from. By increasing the number of nozzles that discharge the fluid, the load (throttle resistance) on the flow of the fluid is reduced, so that the fluid sucked up by the water supply pump 33 increases, and as a result, a large amount of fluid can be supplied to the sand basin 2. As a result, the first low water level TLWL or the second low water level LWL is less likely to occur, so that the number of times the sand lifting pump 61 executes stop and restart can be reduced. Here, it is desirable that the other nozzle is a sand collecting nozzle 91 provided in the nozzle header to be discharged next. By discharging the fluid from the nozzle header to be discharged next, the sand on the bottom plane 71 and the small trough 72 to be flowed next can be preliminarily flowed, so that the residual sand can be further suppressed. can. Further, the fluid to be additionally discharged may be a fluid stored in other equipment. Further, even if the first low water level TLWL or the second low water level LWL is reached, the sand lifting pump 61 is not stopped, and instead of the stop, the fluid pumped up by the water supply pump 33 and the fluid stored in other equipment are used. It may be configured to supply to the sand basin 2. In this configuration, the fluid stored in the other equipment may be stopped from being supplied to the sand basin 2 when the second high water level THWL or the third high water level HWL is reached. By reducing the number of times the sand pump 61 repeats stopping and driving, deterioration of the sand pump 61 can be suppressed and the life of the sand pump 61 can be extended.

By the way, in the present embodiment, the discharge port 911 is arranged near the bottom of the sand basin 2. On the other hand, for example, in Japanese Patent Application Laid-Open No. 2011-245391, a sand collecting means 9 provided with a discharge port 911 is arranged in the upper portion of the sand basin 2, a fluid is discharged toward the side wall W, and the wall surface of the side wall W is fluid. A sand basin 2 has been proposed so that the water flows down.

FIG. 15 is a cross-sectional view of a sand basin similar to FIG. 5 showing a case where the sand collecting means is arranged in the upper portion of the sand basin and a case where the sand collecting means is arranged in the vicinity of the bottom of the sand basin. In FIG. 15, the sand collecting means arranged in the upper portion of the sand pond is indicated by a two-dot chain line. Further, among the lines indicating the pipes and the side walls, the lines intersecting with the sand collecting means arranged in the upper portion of the sand basin are shown by omitting the intersecting portions.

In FIG. 15, a virtual upper nozzle header 90 is shown in the upper portion of the sand basin 2. The upper nozzle header 90 is used in place of the first nozzle header 9a. An obliquely standing dust remover 5 is arranged at the upstream end of the sand basin 2. The sand collecting means 9 needs to be arranged so as not to interfere with the dust remover 5. Therefore, the upper nozzle header 90 arranged in the upper portion of the sand basin 2 is located on the downstream side as compared with the case where the upper nozzle header 90 is arranged in the vicinity of the bottom of the sand basin 2 as shown in FIG. That is, the upper nozzle header 90 has to be arranged on the downstream side by a distance S from the first nozzle header 9a. As described above, the upper portion of the endless chain 51 and the filtration screen 53 constituting the dust remover 5 overlaps the bottom plane 71 and the main trough 8 in the longitudinal direction. Therefore, even if the fluid is discharged from the upper nozzle header 90, a portion of the bottom plane 71 where the discharged fluid does not reach the portion on the most upstream side is generated. If the dust remover 5 and the upper nozzle header 90 are arranged upstream by a distance S from the positions shown in FIGS. 5 and 15, the fluid can reach the most upstream portion of the bottom plane 71. However, in that arrangement, the length of the sand basin 2 in the longitudinal direction becomes long. As a result, the sand basin 2 becomes large and requires a large amount of land to install the sand basin 2, and the sand basin 2 becomes expensive. In the sand basin 2 of the present embodiment, since the first nozzle header 9a is arranged near the bottom of the sand basin 2, the upper nozzle header 90 arranged in the upper portion of the sand basin 2 is used as compared with the case where the upper nozzle header 90 is used. It has the effect of suppressing the increase in size of the sand basin 2 and providing the sand basin 2 at a low cost.

Next, a modification of the connection surface 73 will be described. In the modification described below, the differences from the embodiments shown in FIGS. 1 to 14 will be mainly described, and the constituent elements having the same names as the constituent elements in the embodiments shown in FIGS. 1 to 14 will be described. Will be described with reference numerals used so far, and duplicate description will be omitted.

FIG. 16 is a cross-sectional view similar to FIG. 3 showing a modified example of the connecting surface.

In this modified example, the point that the connecting surface 73 is formed by a curved surface is different from the example shown in FIG. The connection surface 73 is composed of a ridge line portion 731 extending along the longitudinal direction, a first connection surface 732, and a second connection surface 733. As shown in FIG. 16, the first connection surface 732 and the second connection surface 733 have a cross-sectional shape of 1/4 circle. That is, the connection surface 73 is composed of a semi-cylindrical surface that protrudes upward as a whole. The ridge line portion 731 is composed of a line at the upper end of the semi-cylindrical shape. Also in this modified example, as in the example shown in FIG. 3, the sand that has settled on the connecting surface 73 in the sewage in the sand basin 2 tends to slide off the connecting surface 73 due to its own weight. However, in the vicinity of the ridge line portion 731, the inclination angle of the connecting surface 73 on the tangent plane becomes loose, so that there is a possibility that sand may remain in the vicinity thereof. On the other hand, since the thickness of the concrete constituting the connecting surface 73 in the pond width direction is thick even in the vicinity of the ridge line portion 731, there is an effect that the ridge line portion 731 portion is less likely to be damaged. One of the first connection surface 732 and the second connection surface 733 is formed in a planar shape as shown in FIG. 3, and the other is formed in a curved surface shape as in the modified example shown in FIG. It may be formed. Further, one or both of the first connection surface 732 and the second connection surface 733 may be formed on a surface in which a curved surface and a plane are combined.

Next, a modified example of the sand collecting means 9 will be described.

FIG. 17A is a diagram showing a first modification of the supply pipe and the sand collection nozzle shown in FIG. 8, and FIG. 17B is a second modification of the supply pipe and the sand collection nozzle shown in FIG. It is a figure which shows.

In this first modification, the wrap joint 934 is not arranged on the supply pipe 92, the supply pipe 92 and the branch pipe 932 are flanged, and the sand collecting nozzle 91 is provided with the ball joint 912. The points are different from the example shown in FIG. 8 (a). In FIG. 17A, the sand collecting nozzle 91 corresponding to the convex wall portion Wa1 is shown by a solid line, and the sand collecting nozzle 91 corresponding to the concave wall portion Wa2 is shown by a two-dot chain line. In this modification, a ball joint 912 is provided between the supply pipe 92 and each discharge port 911. With this ball joint 912, the discharge direction of the fluid can be steplessly changed not only in the rotation direction around the axis of the supply pipe 92 but also in various other directions. Therefore, it is possible to finely adjust the discharge direction for each discharge port 911. A lap joint 934 may be arranged on the supply pipe 92, and a ball joint 912 may be further provided on the sand collecting nozzle 91. In this case, the lap joint 934 corresponds to an example of the batch changing means, and the ball joint 912 corresponds to an example of the individual direction changing means.

In the second modification, the wrap joint 934 is not arranged on the supply pipe 92, the supply pipe 92 and the branch pipe 932 are flanged, and the sand collecting nozzle 91 is attached in the circumferential direction of the supply pipe 92. The point that a plurality of portions 924 are formed is different from the example shown in FIG. 8 (a). In FIG. 17B, the sand collecting nozzle 91 corresponding to the convex wall portion Wa1 is shown by a solid line, and the sand collecting nozzle 91 corresponding to the concave wall portion Wa2 is shown by a two-dot chain line. In this modification, the mounting portions 924 of the sand collecting nozzle 91 are formed at six locations in the circumferential direction of the supply pipe 92. As a result, after the supply pipe 92 is fixed to the branch pipe 932, the sand collecting nozzle 91 can be mounted on any mounting portion 924 from the six mounting portions 924. Before mounting the sand collecting nozzle 91, plug members are mounted on all mounting portions 924. When the sand collecting nozzle 91 is attached, the sand collecting nozzle 91 is attached after removing the plug member. A lap joint 934 may be arranged on the supply pipe 92, and a mounting portion 924 may be further formed on the supply pipe 92. In this case, the lap joint 934 corresponds to an example of the batch changing means, and the mounting portion 924 corresponds to an example of the individual direction changing means. In this modification, six mounting portions 924 are formed in the circumferential direction, but the mounting portions 924 may be two or more and five or less, or seven or more.

Next, a modification of the main trough 8, each covering member 13, 14, 15, and the bottom plane 71 will be described.

FIG. 18 is a cross-sectional view similar to FIG. 5 showing a modified example of the main trough, the covering member, and the bottom plane.

This modification differs from the example shown in FIG. 5 in that the main trough 8, each covering member 13, 14, 15, and the bottom plane 71 are arranged so as to be inclined downward toward the sand collecting pit 6. .. In FIG. 18, in order to show the inclination in an easy-to-understand manner, the inclination of the main trough 8, each covering member 13, 14, 15, and the bottom plane 71 is exaggerated. As shown in FIG. 18, the bottom plane 71 is inclined downward by about 0.5 degrees in the longitudinal direction so that the end portion on the side of the sand collecting pit 6 is deepest toward the sand collecting pit 6. Further, the upstream first main trough 815 and the downstream main trough 82 are also inclined downward by about 0.5 degrees toward the sand collecting pit 6 like the bottom plane 71, and are connected to the sand collecting pit 6. The part is the deepest. Further, the first covering member 13 and the third covering member 15 are also inclined downward by about 0.5 degrees toward the sand collecting pit 6, and the portion connected to the sand collecting pit 6 is the deepest. The upstream first main trough 815 and the second covering member 14, which are not shown in FIG. 18, are also inclined downward by about 0.5 degrees toward the sand collecting pit 6. In this modification, by providing the covering members 13, 14 and 15, not only the transporting force of sand in the main trough 8 is increased, but also the main trough 8 and the covering members 13, 14 and 15 are tilted. The flow of the fluid discharged into each of the covering members 13, 14 and 15 is assisted. This allows the sand deposited on the main trough 8 to be transported over a longer distance. The inclination angle may be appropriately set according to the length of the main trough 8.

FIG. 19 is a cross-sectional view similar to FIG. 8A showing a bottom plane near the upstream end of the sand pond and a bottom plane near the sand collecting pit in the modified example shown in FIG. The side wall and bottom plane are also shown in FIG.

FIG. 19 shows the height direction of the bottom plane 71 when the bottom plane 71 is inclined downward toward the sand collecting pit 6 side so that the end on the sand collecting pit 6 side is the deepest as shown in FIG. It shows the difference in the position of. In FIG. 19, the bottom plane 71 near the upstream end of the sand basin 2 is shown by a solid line, and the bottom plane 71 near the sand collecting pit 6 is shown by a two-dot chain line. As shown in FIG. 19, in this case, the bottom plane 71 exists at a position lower in the vicinity of the sand collecting pit 6 than in the bottom plane 71 near the upstream end of the sand basin 2. As shown in the figure, even if the fluid is discharged from the discharge port 911 at the same position, in the upstream end of the sand sink 2 and in the vicinity of the sand collection pit 6, the bottom plane 71 is in the height direction. Since the positions are different, a difference in distance Y occurs at the arrival point of the discharged fluid to the bottom plane 71. In particular, in the sand basin 2 having a long length in the longitudinal direction, the distance Y becomes long, and even the optimum discharge direction for one of the upstream end of the sand basin 2 and the vicinity of the sand collecting pit 6 is inefficient for the other. It may be in the discharge direction. In the present embodiment, since the discharge direction of the fluid from the discharge port 911 can be changed, the fluid is set to the optimum discharge direction corresponding to the height of the bottom plane 71 (distance from the supply pipe 92 to the bottom plane 71). Can be discharged.

Next, a modified example when the height of the main trough 8 is increased will be described.

FIG. 20 is an explanatory diagram similar to FIG. 13 showing an example of detecting the water level when the height of the main trough is increased.

In the example shown in FIG. 13, each covering member 13, 14, 15 was formed at a height exceeding half the height of the main trough 8. The upper end positions 13b of the covering members 13, 14 and 15 were substantially the same as the lower end 72b of the small trough 72 (the upper end 8b of the main trough 8). As described above, the operation mode A of the sand lifting pump 61 is a control mode for maintaining the state in which the covering members 13, 14 and 15 are submerged in water. Therefore, the upper end positions 13b of the covering members 13, 14 and 15 are maintained. It is necessary to set the first low water level TLWL above. Further, since the operation mode B of the sand lifting pump 61 is a control mode in which the water level is maintained below the lower end 72b of the small trough 72, the operation mode B is lower than the lower end 72b of the small trough 72. 3 It is necessary to set a high water level HWL. In the example shown in FIG. 13, in order to satisfy the condition that the first low water level TLWL is set above the upper end position 13b and the third high water level HWL is set below the lower end 72b, the first low water level TLWL is used. There is no choice but to set the third high water level HWL below. As a result, there is no overlap in the maintenance range of the water level in the operation mode A and the operation mode B, and when switching from one mode to the other mode, a waiting time is generated until the water level falls within the range of the other mode. Was there. As shown in FIG. 20, when the height of the main trough 8 is increased and the covering members 13, 14 and 15 are arranged in the lower portion of the main trough 8, the upper end positions of the covering members 13, 14 and 15 are located. 13b is located below the lower end 72b of the small trough 72. Therefore, even if the above conditions are satisfied, the third high water level HWL can be set above the first low water level TLWL. That is, since a part of the water level range D1 in the operation mode A and a part of the water level range D2 in the operation mode B can be overlapped, the waiting time after the mode switching can be deleted or reduced.

The present invention is not limited to the above-described embodiments and modifications, and various modifications can be made within the scope of the claims. For example, in the present embodiment, the present invention is used for the sand basin 2 of the sewage treatment facility 1 into which sewage and rainwater flow in, but the present invention can also be applied to the sand basin of the rainwater treatment facility in which only rainwater flows. Further, in the present embodiment, after the sand deposited on the bottom plane 71 and the small trough 72 on the upstream side of the sand collecting pit 6 is poured, the sand is deposited on the bottom plane 71 and the small trough 72 on the downstream side of the sand collecting pit 6. Although the sand that has been collected is being washed away, the sand that has previously accumulated on the bottom plane 71 and the small trough 72 on the downstream side may be washed away. Further, in the present embodiment, an example in which the dust remover 5 and the protruding wall 10 are arranged at the upstream end of the sand basin 2 is shown, but the dust remover 5 and the protruding wall 10 are arranged at the downstream end of the sand basin 2. You may. When the dust remover 5 and the protruding wall 10 are arranged at the downstream end of the sand basin 2, two downstream main troughs 82 are provided and arranged on the left side wall Wa side and the right side wall Wb side with respect to the protruding wall 10. do it. Then, the ridgeline portion, the first connecting surface, and the second connecting surface may be formed between the two downstream main troughs 82 except for the region where the protruding wall 10 is provided. Further, in the present embodiment, the main trough 8 is provided with one discharge port for discharging the fluid into the transport space FS at the end (tip portion) on the opposite side of the sand collection pit 6, but each covering member is provided. 13, 14, 15 An additional nozzle having a discharge port may be provided at an intermediate position in the extending direction or the like. In particular, when the length of each covering member 13, 14, 15 in the extending direction is long or the fluid discharge pressure is low, it is desirable to add a nozzle at an intermediate position or the like. Further, in the present embodiment, the fluid is discharged into the transport space FS in a state where the covering members 13, 14 and 15 are completely submerged in water, but a part of the covering members 13, 14 and 15 is submerged in water. If it is submerged, the fluid may be discharged with the atmosphere remaining in the transport space FS. Further, in the present embodiment, the fluid is discharged in a state where the trough first discharge port 831a, the trough second discharge port 832a, or the trough third discharge port 84a is completely submerged in water. , 84a may be partially submerged in water and the remaining part exposed to the atmosphere to discharge the fluid. However, in these cases, a loss occurs in the flow of the discharged fluid, especially at the interface between the atmosphere and water. Therefore, with the covering members 13, 14, 15 and the trough first discharge port 831a, trough second discharge port 832a, and trough third discharge port 84a completely submerged in water, their discharge ports 831a, 832a, 84a It is desirable to discharge the fluid from.

Further, although the present embodiment has been described by taking as an example four sewage treatment facilities 1 provided in parallel, the number of the sewage treatment facilities 1 may be one or any number. Further, the present embodiment has been described in the so-called low-pressure sand collection method sand settling basin 2 in which the sewage in the sand settling basin 2 is drained and collected. It can also be applied to ponds. Further, the present embodiment has been described by taking as an example a check valve 641 that opens and closes the valve by the flow of the fluid sucked up by the sand pump 61 as a valve for preventing backflow, but the valve is opened and closed by the driving force of the electric actuator. A valve may be used. In addition, although the sand lifting pipe 64 is connected to the upper portion of the transport pipe 66, the sand lifting pipe 64 may be connected to the side of the transport pipe 66 or may be connected to the lower portion. Further, the sand-lifting pipe 64 is connected to the transport pipe 66 while gradually approaching the transport pipe 66 toward the transport direction of the transport pipe 66, but the sand-lifting pipe 64 and the transport pipe 66 are T-shaped. The sand raising pipe 64 may be connected to the transport pipe 66 from the orthogonal direction so as to form a shape.

According to the present embodiment or a modification thereof, the occurrence of defects in the sand basin 2 can be suppressed. In addition, sand can be collected efficiently. Further, the sand deposited on the bottom plane 71, the small trough 72, and the connecting surface 73 can be flowed by a fluid without remaining. Further, even in a sand basin in which the left side wall Wa or the right side wall Wb is not formed in a straight line, the linear supply pipe 92 can be used, so that the sand basin 2 can be provided at low cost. In addition, even if the shape of the side wall W is unknown when designing the sand basin 2 or creating the supply pipe 92, the discharge direction can be adjusted when constructing the sand basin 2, so that the sand basin 2 can have various shapes. Can respond flexibly. Further, the sand settled on the connecting surface 73 slides down the first connecting surface 732 or the second connecting surface 733 and is deposited on the upstream first main trough 815 or the upstream second main trough 816. No sand remains between the main trough 815 and the upstream second main trough 816. Further, in the present embodiment, the inclination angles of the first bottom surface 711 and the second bottom surface 712 are set to a gentle inclination angle (about 5 degrees) so that the accumulated sand can be flowed by the fluid discharged from the discharge port 911. There is. As a result, the sand basin 2 can be created without digging deep into the ground. On the other hand, by making the connection surface 73 at a steeper angle than the first bottom surface 711 and the second bottom surface 712, the connection surface 73 is configured so that the fluid discharged from the discharge port 911 does not reach the connection surface 73. The sand that has settled in can be deposited on the upstream first main trough 815 or the upstream second main trough 816.

In addition, many sand basins 2 have a length of 20 meters or more in the longitudinal direction. In the conventional sand basin 2, the main trough 8 is inclined downward, for example, once toward the sand collecting pit 6 side. Therefore, the sand collecting pit 6 side end portion (rear end portion) is deeper in proportion to the length of the sand basin 2 with respect to the depth position where the pond end side end portion (tip portion) of the main trough 8 is arranged. Placed in position. Further, since the bottom plane 71 is formed at the same inclination angle as the main trough 8, the bottom plane 71 is also arranged at a deep position on the sand collecting pit 6 side. When the length of the sand basin 2 in the longitudinal direction is long, the portion of the main trough 8 and the bottom plane 71 on the sand collecting pit 6 side is located at a deeper position as compared with the case where the length of the sand basin 2 in the longitudinal direction is short. Will be placed. When constructing the sand basin 2, the ground is dug below the deepest position of the sand basin 2, and then the sand basin 2 is formed of concrete. If the main trough 8 and the bottom plane 71 are inclined, the sand collecting pit 6 will be placed at a deeper position than when it is not inclined, so it is necessary to dig deep into the ground, which is troublesome for digging work. It takes. In addition, when forming the bottom plane 71 with concrete from the dug down position, it is necessary to gradually thicken the concrete from the sand collecting pit 6 side toward the end of the sand basin in order to incline the bottom plane 71. , Used a lot of concrete. As a result, there is a problem that the sand basin 2 becomes expensive. In the present embodiment, since the covering members 13, 14, and 15 are provided to improve the sand collection efficiency, even if the inclination angles of the main trough 8 and the bottom plane 71 are loosened, the sand in the main trough 8 is collected in the sand collection pit. Can be transported to 6. The inclination angle is preferably 0 degrees or more and less than 1 degree, and more preferably 0 degrees or more and 0.5 degrees or less. Since the inclination angle is loosened, it is not necessary to dig deep into the ground, and the amount of concrete used can be small, so that the sand basin 2 can be created at low cost.

The following invention concept can also be extracted from the sand basin of the present embodiment.

In a sand basin where the sand contained in the received water settles
A groove provided at the bottom of the pond below the side wall and extending in a predetermined direction,
With the bottom surface provided at the bottom of the pond and connected to the groove,
A plurality of discharge ports for discharging the fluid for flowing the sand settled on the bottom surface from the side wall side toward the groove, and
It has a supply pipe provided with the discharge port, and has
The plurality of discharge ports are those that discharge the fluid toward the center side in the pond width direction from the axis of the supply pipe provided with the discharge port, and those that discharge the fluid toward the outside in the pond width direction from the axis of the supply pipe. A sand basin characterized by the fact that some of them discharge fluid.

In addition, the following invention concept can be extracted from the sand basin of the present embodiment.

In a sand basin where the sand contained in the received water settles
A groove provided at the bottom of the pond below the side wall and extending in a predetermined direction,
With the bottom surface provided at the bottom of the pond and connected to the groove,
It has a discharge port for discharging a fluid for flowing the sand settled on the bottom surface from the side wall side toward the groove.
A sand basin characterized in that the discharge direction of the fluid discharged from the discharge port can be changed.

In this sand basin
The supply pipe provided with the discharge port and
It has a mother pipe that supplies fluid to the supply pipe,
The supply pipe may be rotatable with respect to the mother pipe about the axial direction of the supply pipe.

Also, in the above sand basin,
The supply pipe may be provided with a plurality of discharge ports.

Furthermore, in the above sand basin,
It has a supply pipe provided with the discharge port, and has a supply pipe.
The discharge port may be capable of changing the discharge direction of the fluid by a ball joint arranged between the supply pipe and the discharge port.

In addition, in the above sand basin
The discharge port has a detachable supply pipe, and has a supply pipe.
The supply pipe may have a plurality of mounting portions to which the discharge port is mounted in the circumferential direction of the supply pipe.

In addition, the following invention concept can be extracted from the sand basin of the present embodiment.

In a sand basin where the sand contained in the received water settles
A groove provided at the bottom of the pond below the side wall and extending in a predetermined direction,
With the bottom surface provided at the bottom of the pond and connected to the groove,
A discharge port for discharging a fluid for flowing sand settled on the bottom surface from the side wall side toward the groove and a plurality of the discharge ports arranged in the predetermined direction on the center side in the pond width direction with respect to the side wall. It has a supply pipe and
The supply pipe has a first region extending from the side wall in the pond width direction with a first interval, and a second region extending from the side wall with a second interval in the pond width direction. ,
The sand basin is characterized in that the discharge port arranged in the first region and the discharge port arranged in the second region can change the discharge direction of the fluid independently of each other.

The number of discharge ports provided in the first region may be plurality or one. When there are a plurality of discharge ports provided in the first region, it is preferable that the discharge directions of the fluids from those discharge ports can be changed collectively. Further, the number of discharge ports provided in the second region may be a plurality or one. Even when there are a plurality of discharge ports provided in the second region, it is preferable that the discharge directions of the fluids from those discharge ports can be changed collectively. The term "collectively changeable" as used herein means that, for example, the portion of the first region and the portion of the second region of the supply pipe rotate separately about the axial direction of the supply pipe. It is realized by doing. In addition, rotatable portions may be provided at both end portions of the first region of the supply pipe, and rotatable portions may be provided at both end portions of the second region. The supply pipe may be a straight pipe or a pipe provided with a slightly bent portion.

The supply pipe is provided with a third region connecting the first region and the second region.
The discharge port provided in the third region can change the discharge direction of the fluid separately from the discharge port provided in the first region and the discharge port provided in the second region. It is also good.

The third region may be an inclined region in which the distance from the side wall gradually changes in the extending direction, or may be a region in which the distance from the side wall gradually changes.

Further, the number of discharge ports provided in the third region may be a plurality or one. When there are a plurality of discharge ports provided in the third region, it is preferable that the discharge direction of the fluid from those discharge ports can also be changed collectively. The term "collectively changeable" as used herein means, for example, that the portion of the third region of the supply pipe is different from the portion of the first region and the portion of the second region of the supply pipe. It is realized by rotating around the axial direction.

In addition, the following invention concept can be extracted from the sand basin of the present embodiment.

In a sand basin where the sand contained in the received water settles
A groove provided at the bottom of the pond below the side wall and extending in a predetermined direction,
With the bottom surface provided at the bottom of the pond and connected to the groove,
It has a plurality of discharge ports which are arranged to face the side wall and discharge a fluid for flowing sand settled on the bottom surface from the side wall side toward the groove.
The side wall has a convex wall portion that protrudes toward the center in the pond width direction and extends in the predetermined direction, and a concave wall portion that is recessed toward the outside in the pond width direction and extends in the predetermined direction.
The discharge port is arranged so as to face each of the convex wall portion and the concave wall portion.
The discharge direction of the fluid discharged from the discharge port arranged to face the concave wall portion is different from the discharge direction of the fluid discharged from the discharge port arranged to face the convex wall portion. A sand basin characterized by a changeable direction change means.

Further, the following invention concept can be extracted from the sand basin of the present embodiment.

In a sand basin where the sand contained in the received water settles
A groove provided at the bottom of the pond below the side wall and extending in a predetermined direction,
With the bottom surface provided at the bottom of the pond and connected to the groove,
A supply pipe arranged facing the side wall and extending in the predetermined direction,
It has a plurality of discharge ports arranged in the supply pipe and discharge a fluid for flowing sand settled on the bottom surface from the side wall side toward the groove.
The side wall has a convex wall portion that protrudes toward the center in the pond width direction and extends in the predetermined direction, and a concave wall portion that is recessed toward the outside in the pond width direction and extends in the predetermined direction.
The discharge port is arranged at a position facing the convex wall portion and a position facing the concave wall portion, respectively.
The supply pipe has a discharge direction of a fluid discharged from a discharge port between a discharge port arranged at a position facing the convex wall portion and a discharge port arranged at a position facing the concave wall portion. A sand basin characterized by being equipped with a changeable direction change means.

Also, in this sand basin
The side wall has an inclined wall portion formed between the convex wall portion and the concave wall portion and extending in a direction inclined with respect to the predetermined direction and the pond width direction.
The discharge port is also arranged at a position facing the inclined wall portion.
The supply pipe has a discharge direction of the fluid discharged from the discharge port between the discharge port arranged to face the convex wall portion and the discharge port arranged to face the inclined wall portion. Equipped with a changeable first-direction changing means,
The discharge direction of the fluid discharged from the discharge port can be changed between the plurality of discharge ports arranged to face the recessed wall portion and the discharge port arranged to face the inclined wall portion. It may be provided with a second direction changing means.

In addition, the following invention concept can be extracted from the sand basin of the present embodiment.

In a sand basin where the sand contained in the received water settles
A groove provided at the bottom of the pond below the side wall and extending in a predetermined direction,
With the bottom surface provided at the bottom of the pond and connected to the groove,
A plurality of discharge ports for discharging the fluid for flowing the sand settled on the bottom surface from the side wall side toward the groove, and
A batch direction changing means capable of collectively changing the discharge direction of the fluid discharged from at least two of the plurality of discharge ports, and
A sand basin provided with an individual direction changing means capable of changing the discharge direction of the fluid discharged from the discharge port for each discharge port.

In addition, the following invention concept can be extracted from the sand basin of the present embodiment.

In a sand basin where the received water flows down in a direction orthogonal to the pond width direction and the sand contained in the water is settled between one side wall and the other side wall constituting the end face in the pond width direction.
The first groove and the second groove provided at the bottom of the pond and extending in the orthogonal direction at intervals in the width direction of the pond, respectively.
It has a protruding wall formed between the first groove and the second groove and protruding upward from the bottom of the pond.
A ridgeline portion extending along the orthogonal direction and a ridgeline portion between the first groove and the second groove portion of the bottom of the pond, excluding the region where the protruding wall is provided, and the ridgeline portion. A sand basin characterized in that a first connecting surface connecting the first groove and a second connecting surface connecting the ridgeline portion and the second groove are formed.

The first connection surface is an inclined surface that is inclined downward from the ridgeline portion toward the first groove.
The second connecting surface may be an inclined surface that is inclined downward from the ridgeline portion toward the second groove.

The first groove is provided on one side wall side thereof, and is provided.
The second groove is provided on the side wall side of the other side wall, and is provided.
A first bottom surface formed between the one side wall and the first groove and inclined downward toward the first groove.
It has a second bottom surface formed between the other side wall and the second groove and inclined downward toward the second groove.
The inclination angles of the first connection surface and the second connection surface may be steeper than the inclination angles of the first bottom surface and the second bottom surface.

A one-sided discharge port for discharging a fluid for flowing sand settled on the first bottom surface from the one side wall side toward the first groove.
It may have a discharge port on the other side for discharging a fluid for flowing the sand settled on the second bottom surface from the side wall side of the other side toward the second groove.

It may be provided with two dust removers arranged between the one side wall and the protruding wall and between the other side wall and the protruding wall, respectively, to remove contaminants contained in the received water.

In addition, the following invention concept can be extracted from the sand basin of the present embodiment.

In a sand basin where the received water flows down in a direction orthogonal to the pond width direction and the sand contained in the water is settled between one side wall and the other side wall constituting the end face in the pond width direction.
The first groove and the second groove provided at the bottom of the pond and extending in the orthogonal direction at intervals in the width direction of the pond, respectively.
A sand collecting pit provided at the bottom of the pond, to which the first groove is connected and to which the second groove is connected,
It has a protruding wall formed between the first groove and the second groove and protruding upward from the bottom of the pond.
A ridgeline portion extending along the orthogonal direction in a portion of the bottom of the pond between the first groove and the second groove and between the sand collecting pit and the protruding wall, and the ridgeline portion. A sand basin characterized in that a first connecting surface connecting the first groove and a second connecting surface connecting the ridgeline portion and the second groove are formed.

In addition, the following invention concept can be extracted from the sand basin of the present embodiment.

In a sand basin where the sand contained in the received water sinks to the bottom of the pond
A groove provided at the bottom of the pond and extending in a predetermined direction,
A first discharge port for discharging a fluid in the predetermined direction in the water collected in the groove, and a first discharge port.
With the bottom surface provided at the bottom of the pond and connected to the groove,
A second discharge port for discharging a fluid for flowing sand accumulated on the bottom surface from the side wall side of the sand basin toward the groove, and a second discharge port.
A sand basin characterized by covering the periphery of a virtual axis extending from the center of the first discharge port toward the predetermined direction and provided with a covering member having an opening at a lower end portion.

In this sand basin, the opening of the covering member may be arranged below the center in the height direction of the groove.

Further, the following invention concept can be extracted from the sand collecting method shown in the present embodiment.

In a sand basin where sand contained in the received water is settled at the bottom of a pond having a groove extending in a predetermined direction and a bottom surface connected to the groove, a sand collecting method for collecting sand accumulated at the bottom of the pond. There,
An underwater discharge step of discharging a fluid in the predetermined direction from a first discharge port in the water collected in the groove,
It has an atmospheric discharge step of discharging a fluid for flowing sand accumulated on the bottom surface from the side wall side toward the groove from a second discharge port to the atmosphere.
The underwater discharge step is a step of discharging a fluid into a space covered by a covering member having an opening at a lower end portion and covering the periphery of a virtual axis extending from the center of the first discharge port in a predetermined direction. A sand collection method characterized by that.

The underwater discharge step is a step performed in a state where the water level is maintained higher than that of the covering member.
The air discharge step may be a step performed in a state where the water level is maintained below the bottom surface.

The process of executing the underwater discharge step after the execution of the atmospheric discharge step may be regarded as a set of sand collection processes, and the sand collection process may be performed a plurality of times.

The underwater discharge step may be executed before the sand collection treatment is performed a plurality of times.

It should be noted that even if the constituent requirements are included only in the description of the embodiment and each modified example described above, the constituent requirements may be applied to the embodiment and other modified examples.

2 Sand basin 61 Sand lifting pump 64 Sand lifting pipe 64c Inclined part 66 Conveying pipe 66b Pipe connection part 641 Check valve

Claims (3)

It is a sand unloading facility installed in a sand basin where the sand contained in the received water settles.
A pump that sucks in the settled sand and
A sand raising pipe connected to the pump and through which sand sucked by the pump passes upward.
It is provided with a transport pipe extending in a direction intersecting with the sand lift pipe and transporting sand that has passed through the sand lift pipe.
The sand lifting pipe is provided with a check valve for preventing backflow from the transport pipe to the pump, and the sand lift in the transport pipe is provided between the backflow prevention valve and the transport pipe. A sand unloading facility characterized by having a portion arranged above a connection portion with a pipe. The sand unloading facility according to claim 1, wherein the sand lifting pipe is connected to an upper portion of the transport pipe. The portion of the sand raising pipe connected to the transport pipe is arranged so as to be inclined with respect to the transport pipe so as to gradually approach the transport pipe toward the transport direction of the transport pipe. The sand unloading facility according to claim 1 or 2, which is characterized by this.

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