JP4267355B2 - Sand collection method and sand collection equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to sediment and sediment in sewage that settles and deposits (hereinafter collectively referred to as “sand”) in rainwater stagnation ponds and sand basins (hereinafter collectively referred to as “storage ponds”) that store sewage. A sand collecting method for collecting the material in a sand collecting pit, and a sand collecting facility for carrying out the method.
[0002]
[Prior art]
Conventionally, a plurality of nozzles are provided at the bottom of a sand basin, and water is sprayed from the nozzle toward the sand collection pit provided at a part of the pond bottom, so that the sand deposited and accumulated on the bottom of the pond is collected into the sand collection pit. There is known a sand collection facility that discharges sand that has been swept away and accumulated in a sand collection pit by discharge means (see, for example, Patent Document 1).
[0003]
In addition, a trough connected to the sand collecting pit is provided at the bottom of the rainwater settling basin, and the collected sand is first collected in the trough by jetting of pressure water, and then the collected sand is collected in the sand collecting pit by injecting pressure water into the trough. Sand facilities are known (see, for example, Patent Document 2).
[0004]
[Patent Document 1]
JP 2002-186955 A
[Patent Document 2]
JP 2002-334217 A
[0005]
[Problems to be solved by the invention]
Each of the above-described technologies is based on the premise of injection of pressure water, which requires a running cost for preparing the pressure water, and has poor cost performance. In addition, assuming sand collection by jetting of pressure water, there is little room to consider the properties of the water flow, and the improvement of the prior art is mainly due to the change of the nozzle location or the installation of mechanical sand collection means, etc. There were many things.
[0006]
In view of the above problems, an object of the present invention is to provide an efficient and cost-effective sand collecting method and sand collecting equipment.
[0007]
[Means for Solving the Problems]
The sand collecting method of the invention of claim 1 is a storage pond having a sand collecting channel having a downward slope toward the sand collecting pit formed at the bottom of the pond, and sand accumulated in the reservoir is put into the sand collecting pit. A sand collection method for collecting, wherein a part of the sewage flowing into the storage pond is stored and retained in a storage tank adjacent to the storage pond when the sewage flows in, and the stored water is reduced when the water level of the storage pond is lowered. The sand is discharged from the upper part of the gradient in the sand collecting flow path, and the accumulated water is collected in the sand collecting pit by the discharge flow toward the sand collecting pit.
[0008]
In the present invention, the settling sedimentation sand can be pushed away into the sand collection pit by the discharge of the stored water. In particular, in a rainwater reservoir, a dry sand basin or the like, sand can be collected effectively if the stored water is discharged in a state where the water level is lowered.
[0009]
In this case, as the stored water to be discharged, what used to store and hold a part of the sewage flowing into the reservoir in advance is used, and at the time of sand collection, it is simply discharged from the upper part of the gradient in the sand collection channel, Extra running costs can be minimized.
[0010]
A sand collecting method according to a second aspect of the present invention is the sand collecting method according to the first aspect, wherein the discharge flow is caused to pulsate by repeatedly releasing and stopping the stored water, and sand accumulated in the storage pond by the pulsation is collected in the sand collecting pit. It is characterized by collecting.
[0011]
In this way, by causing pulsation in the discharge flow, it is possible to roll up the sand settling on the pond bottom, so that the sand settling can be effectively moved to the sand collecting pit, and sand collection efficiency can be improved.
[0012]
The sand collecting facility of the invention of claim 3 includes a sand collecting pit formed at the bottom of the reservoir where the sand in the inflowing sewage settles, and a sand collecting pit formed at the bottom of the reservoir and descending toward the sand collecting pit. A sand collecting flow path having a gradient, a temporary storage tank for storing a part of the inflowing sewage, a discharge port disposed upstream of the sand collection flow path for discharging the stored water in the temporary storage tank, and a temporary storage tank Control means for controlling the retention and release of the stored water in the interior, maintaining the state in which the stored water is stored during the retention, and releasing the stored water from the discharge port during the release. It is configured to accumulate sand that settles and deposits in the sand collecting pit.
[0013]
In the invention of claim 3, the sedimentation sediment deposited can be pushed away into the sand collecting pit by the discharge of the stored water stored and held in the temporary storage tank. In particular, in a rainwater reservoir, a dry sand basin or the like, sand can be collected effectively if the stored water is discharged in a state where the water level is lowered. In addition, pulsation can be generated in the discharge flow by controlling the discharge of the stored water by the control means, so that the sand sediment deposited on the bottom of the pond is effectively rolled into the sand collecting pit while rolling up using the pulsation. It can be collected and sand collection efficiency can be improved. In addition, as the stored water to be discharged, one that has previously stored and retained a part of the sewage flowing into the storage pond is used, and at the time of sand collection, it is simply discharged from the upper part of the gradient in the sand collection channel. Running costs can be minimized.
[0014]
According to a fourth aspect of the present invention, there is provided the sand collecting facility according to the third aspect, wherein the temporary storage tank is a sealed storage tank whose upper end is closed and whose lower end communicates with the discharge port via a trap portion; Supply and discharge means for supplying and discharging air to and from the upper sealed space, and the control means controls the supply and discharge means to draw sewage into the storage tank and sewage It is characterized by holding and releasing.
[0015]
In the invention of claim 4, a part of the sewage that has flowed into the storage pond can be drawn into the storage space through the discharge port by removing the air from the upper sealed space in the storage tank (evacuating). In addition, by maintaining the decompressed state of the upper sealed space of the storage tank, the stored water can be held in the storage tank regardless of the water level on the storage pond side. Moreover, at the time of sand collection, the stored water can be discharged to the sand collection channel through the discharge port by supplying air (natural supply or forced supply) to the upper sealed space in the storage tank. The air supply in this case may be natural air supply by opening the upper sealed space to the atmosphere, or may be forced air supply by some pressurizing means. In either case, the stored water can be discharged while utilizing the water level difference between the storage pond and the storage tank, so that unnecessary energy consumption can be suppressed as much as possible.
[0016]
A sand collecting facility according to a fifth aspect of the present invention is characterized in that, in the third or fourth aspect, a turbulent flow forming portion is disposed in the sand collecting flow path.
[0017]
When the turbulent flow forming portion is disposed in this way, the turbulent flow forming portion can form a turbulent flow in the discharge flow, so that the sand settling around the turbulent flow forming portion can be rolled up, and effective sand collection Is possible.
[0018]
The sand collecting facility according to the invention of claim 6 is the sand collecting facility according to claim 5, wherein the turbulent flow forming section is a single body of a plate-like body, a cylindrical body, or a triangular prism body installed in an upright state, or a plurality thereof, or It is characterized by comprising a plurality of combinations of each type.
[0019]
In the invention of claim 6, various forms of turbulent flow forming portions can be appropriately selected depending on the capacity and shape of the sand basin.
[0020]
A sand collection facility according to a seventh aspect of the present invention is the sand collection facility according to the sixth aspect, wherein the turbulent flow forming portion comprises a triangular prism body installed in an upright state, and one of the side surfaces of the triangular prism body is The apex angle that is abutted and fixed to the side wall of the sand collecting channel and that is located upstream of the apex angles of the triangular cross section is set to be equal to or greater than the apex angle that is located downstream. Features.
[0021]
By providing the turbulent flow forming part under such conditions, the discharge flow of the stored water does not branch even if it collides with the turbulent flow forming part, and all the flow is guided in one direction (the center in the width direction of the flow). Flow. Accordingly, it is difficult to cause a problem that dust or the like is caught on the turbulent flow forming portion. In addition, since the inclined surface on the downstream side of the turbulent flow forming portion is a gentle inclined surface as compared with the inclined surface on the upstream side, a smooth flow along this inclined surface occurs, and as a result The flow stays due to the presence of the turbulent flow forming portion.
[0022]
The sand collecting facility according to an eighth aspect of the present invention is the sand collecting facility according to the seventh aspect, wherein a plurality of the turbulent flow forming portions are alternately arranged on the left and right side walls of the sand collecting flow path along the direction of the discharge flow. It is characterized by that.
[0023]
Thus, when the turbulent flow forming portions are alternately arranged on the left and right, the discharge flow is sent toward the center by the turbulent flow forming portions arranged alternately on the left and right. Accordingly, each flow from the left and right becomes a zigzag flow, and the turbulent flow is further generated by the interference action of each flow, and the sand collecting effect is improved by the effect of rolling up the sand by the turbulent flow.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic perspective view showing a sand collection facility according to the first embodiment, and FIG. 2 is a side sectional view of the sand collection facility. Moreover, FIG. 3 is a top view which shows the structure of the turbulent flow formation part for forming a turbulent flow in the flow of the water discharged | emitted from a sand collection facility.
[0025]
The sand collection facility 2A according to the present embodiment assumes a sand collection facility in a rainwater reservoir. Rainwater reservoirs are used to store or settle some of the initial rainwater in rainy weather, rainwater discharge rooms, pumping stations, etc. in the combined sewers in order to reduce the pollution load discharged to public water bodies. The facility that discharges and stores the sewage that has been discharged and sent to a treatment plant, etc., in principle, after the rain has ended. The shape of the rainwater reservoir is usually rectangular or square, although it varies depending on the form of the site and the arrangement of facilities. The structure is a watertight reinforced concrete structure.
[0026]
A rainwater reservoir (reservoir) 1A according to the present embodiment is formed by dividing a large reservoir into a plurality of parts in a fixed direction, and a sand collecting facility 2A is provided for each rainwater reservoir 1A. . Hereinafter, one of the rainwater reservoir 1A and the sand collecting facility 2A will be extracted and described.
[0027]
As shown in FIGS. 1 and 2, the rainwater reservoir 1 </ b> A has a rectangular housing shape in plan view, and a side wall 11 is provided between adjacent rainwater reservoirs. The left and right side walls 11 are boundary walls on the long side of the rainwater reservoir 1A having a rectangular shape in plan view. A temporary storage tank 3 is formed on one short side of the rainwater reservoir 1A, and a trough 41 is formed on the bottom of the other short side. The trough 41 communicates with the drain pit 4 and has a downward slope toward the drain pit 4. Further, the pond bottom 21 of the rainwater catchment basin 1 </ b> A is a sand collecting channel that is inclined downward toward the trough 41.
[0028]
The temporary storage tank 3 includes a sealed storage tank 32 and a vacuum forming facility (supply / discharge means) 33 as main components. A discharge port 31 is formed in the lower part of the storage tank 32, and a vacuum forming facility 33 is disposed in the upper part of the storage tank 32. The upper part of the storage tank 32 is sealed.
[0029]
The vacuum forming equipment 33 is connected in communication with the suction pipe 34, a suction pipe 34 protruding into the tank from the ceiling of the storage tank 32, a float valve 35 formed at the suction port of the suction pipe 34 to prevent inflow of sewage. A vacuum pump 36, an air inflow pipe 37 communicating with the atmosphere, and a vacuum release valve 38 for opening and closing the air inflow pipe 37. A control means (not shown) is provided for appropriately controlling opening / closing of the vacuum release valve 38, driving / stopping of the vacuum pump 36, and the like.
[0030]
On the other hand, the discharge port 31 covers the opening 31a formed in the width direction of the pond bottom 21, the trap part 31b that connects the opening 31a and the pond bottom 21, and the opening 31a and the trap part 31b from above. It comprises a curved flange 31c for directing the discharged water toward the pond bottom 21 when the stored water is discharged.
[0031]
When using the equipment configured as described above, the vacuum release valve 38 is initially opened. When the raw water (combined sewage) flows into the rainwater reservoir 1A during the rain in this state, the raw water also flows into the storage tank 32 through the discharge port 31, and as a result, the rainwater reservoir 1A and The water level with the storage tank 32 becomes the same. In this state, the vacuum release valve 38 is closed and the vacuum pump 36 is driven to create a vacuum state above the storage tank 32.
[0032]
In addition, at the above-mentioned water level, if it is not sufficient to secure a necessary amount at the time of water discharge, sewage can be sucked from the rainwater reservoir 1A side by driving the vacuum pump 36. At that time, when the drawn water level reaches the float valve 35, the driving of the vacuum pump 36 is stopped.
[0033]
As long as this state is maintained, the vacuum state in the storage tank 32 is maintained by the action of the trap portion 31b of the discharge port 31, and the stored water is retained.
[0034]
On the other hand, when the stored water held in the storage tank 32 is discharged, the vacuum release valve 38 is opened and opened to the atmosphere.
[0035]
Since the bottom of the pond 21 from the discharge port 31 toward the trough 41 has a downward slope, the stored water discharged from the discharge port 31 flows toward the trough 41 and then flows into the drain pit 4. By this flow, sand (including earth and sand and dust) accumulated on the pond bottom 21 is washed away and collected into the drain pit 4 through the trough 41.
[0036]
The drainage pit 4 is provided with a suction port for a transfer pump facility 5 for pumping stored water. This transfer pump facility 5 is a facility for sending stored water to a treatment plant or the like after the end of rain, and is also used as a means for discharging sand collected in the drain pit 4 in this embodiment. In addition, another sand pump or the like can be disposed in the drain pit 4 to serve as sand discharging means.
[0037]
As is clear from the above description, the sand collecting facility 2A includes a trough 41 serving as a “sand collecting pit”, a pond bottom 21 of a stormwater reservoir 1A serving as a “sand collecting channel”, a temporary storage tank 3, and a discharge port 31. The control means (not shown) for controlling the retention / release of sewage in the temporary storage tank 3.
[0038]
In the sand collection facility 2A, the temporary storage tank 3 is provided in only one place for one rainwater reservoir 1A. However, the temporary storage tank 3 may be provided in a plurality of places. For example, the temporary storage tank 3 can be installed on the upstream side of the trough 41, and sand can be transferred to the drain pit 4 smoothly using the stored water stored in the temporary storage tank 3. In this case, the trough 41 corresponds to the “sand collecting channel” and the drain pit 4 corresponds to the “sand collecting pit”.
[0039]
Next, the turbulent flow forming unit 6A, which is an element of the sand collecting facility, will be described with reference to FIG. 1, FIG. 2, and FIG. FIG. 3 is a schematic enlarged view of the turbulent flow forming portion 6A in the present embodiment. A plurality of the turbulent flow forming portions 6A are arranged on the pond bottom 21 and have the same shape. Therefore, one of them will be extracted to explain the structure and action, and then the interaction and the like obtained by the involvement of the plurality of turbulent flow forming parts 6A will be explained.
[0040]
As shown in FIG. 3, the turbulent flow forming portion 6 </ b> A is composed of a triangular prism body installed in a vertically standing state. More specifically, it is composed of right-angled triangular pillars whose three apex angles of the cross-sectional triangle are 30 °, 60 °, and 90 °, respectively. Among the three side surfaces 61a, 61b and 61c, the turbulent flow forming portion 6A made of this triangular prism body has the side surface 61a which has the maximum area and is the opposing surface of the right apex as the side wall (sand collecting channel) of the rainwater reservoir 1A. The side surface of the pond 11 is fixed to the pond bottom 21.
[0041]
The apex angle α located upstream of the triangular cross section is 60 °, the apex angle β located downstream is 30 °, and the apex angle α on the upstream side is the apex angle β on the downstream side. Is bigger than. Accordingly, when viewing the two side surfaces 61b and 61c that face the flow in an inclined posture, the side surface 61c on the downstream side is more inclined than the side surface 61b on the upstream side. Here, “upstream side” and “downstream side” refer to the upstream side and the lower side of the pond bottom 21 having a downward slope as the downstream side.
[0042]
The apex angles α, β and γ are not limited to the above example, but the apex angle located on the upstream side is set to be equal to or greater than the apex angle located on the downstream side. It is good. Further, the side face that is in contact with and fixed to the side wall 11 of the rainwater reservoir 1A does not necessarily need to be the side face having the maximum area.
[0043]
Next, the operation of the turbulent flow forming portion 6A will be described.
First, let us consider a case where stored water is discharged in a state where the turbulent flow forming portion 6A is not formed. In that case, a rectified flow is generated in the pond bottom 21 after a lapse of a certain time, and the sand accumulated on the pond bottom 21 is gradually wound up from the upstream side and the surface layer and pushed downstream by the fluid pressure of this flow. ,it is conceivable that.
[0044]
On the other hand, when the turbulent flow forming portion 6A is formed in the flow, it is possible to expect the effect of partially breaking the rectification and forming the turbulent flow to roll up the accumulated sand. And it is thought by this winding up that sediment sand can be pushed away effectively downstream. In particular, according to the turbulent flow forming portion 6A, the following effects can be expected.
[0045]
That is, at least one of the side surfaces 61a, 61b, 61c of the turbulent flow forming portion 6A made of a triangular prism body is fixed in contact with the side wall 11 of the rainwater reservoir 1A. For example, the flow is directed to the center while being guided by the side surface 61b without branching at the apex angle α. Therefore, there is no possibility that dust or the like is caught on the apex angle α.
[0046]
The flow guided to the center by the side surface 61b is then separated from the turbulent flow forming portion 6A in the vicinity of the apex angle γ to cause turbulent flow. Further, since the apex angle β on the downstream side is smaller than the apex angle α, the side surface 61c forms a gentle slope toward the downstream side and does not create a flow retention state (dead space).
[0047]
The above is the description of the turbulent flow forming unit 6A alone. In this embodiment, a plurality of the turbulent flow forming portions 6A are arranged. Further, this arrangement is also alternately arranged on the left and right side walls 11 of the pond bottom 21 from the upstream side to the downstream side (in the direction of the discharge flow). With such an alternating left and right arrangement, the discharge flow becomes a flow that bends left and right alternately (zigzag flow), and the interference action of each flow increases the generation of turbulence and enhances the sand winding action. .
[0048]
In addition, you may arrange | position the turbulent flow formation part 6A symmetrically. In that case, compared to the above-described alternate arrangement, there is a portion where the channel width is locally reduced between the turbulent flow forming portions 6A, 6A facing each other. .
[0049]
Next, another embodiment relating to the “turbulent flow forming part” will be described.
FIG. 4 is a plan view showing a state in which a plurality of various turbulent flow forming portions 6A, 6B, 6C are arranged. Disposed on the most upstream side is the turbulent flow forming portion 6A described above. In this illustrated example, the turbulent flow forming portion 6A is not fixed to the side wall 11 of the rainwater reservoir 1A but is erected in an independent state. The next turbulent flow forming portion 6B is a plate-like body, and the side surface is arranged in an inclined posture with respect to the flow direction. The next turbulent flow forming portion 6C is a columnar body standing upright. These turbulent flow forming portions 6A, 6B, and 6C may be appropriately selected according to the shape of the facility and the properties of the raw water. For example, one type or a plurality of types of turbulent flow forming units may be arranged, or a plurality of types of turbulent flow forming units may be arranged in combination.
[0050]
Next, a sand collection method using the sand collection facility 2A will be described with reference to FIG. Normally, the vacuum release valve 38 is open. When the raw water flows in during rain or the like, and the water level reaches point A, for example, the water level in the storage tank 32 also reaches A. However, since the water level is still insufficient, the vacuum release valve 38 is first closed and the vacuum pump 36 is driven by the command from the control means. As a result, raw water is drawn into the storage tank 32 and the water level in the storage tank 32 reaches B. Then, the suction rod 34 is closed by the action of the float valve 35, and the suction is stopped. Thereby, the water level in the storage tank 32 is maintained in this state.
[0051]
When the water level of the rainwater reservoir 1A reaches point C during fine weather, the sand collection work of the sand S accumulated on the pond bottom 21 is performed. In this case, the vacuum release valve 38 is opened by a command from the control means to release the state of retaining the stored water. Then, the stored water is discharged from the discharge port 31 and pushes the sand S to the trough 41 and the drainage pit 4 side. The sand S collected in the drain pit 4 is discharged by the action of the transfer pump facility 5.
[0052]
As another sand collecting method, the vacuum release valve 38 is repeatedly opened and closed at regular intervals, and the discharge and stoppage of the stored water are repeated to cause pulsation in the discharge flow. Can be effectively swept away.
[0053]
Next, the sand collection facility 2B according to the second embodiment of the present invention will be described.
FIG. 5 is a system diagram of the main sand collecting facility attached to the sand basin, FIG. 6 is a front view of a portion where a discharge device as a component of the sand collecting facility is installed, and FIG. 7 is a perspective view showing a schematic configuration of the same portion. 8 is an exploded perspective view showing the configuration of the discharge device, FIG. 9 is a cross-sectional view taken along the line IX-IX in FIG. 8, FIG. 10 is a detailed cross-sectional view of the portion X in FIG. It is sectional drawing of a XI part.
[0054]
As shown in FIG. 5, the sand collection facility 2B is a facility for sending sand deposited in the sand settling basin 1B in the sewage treatment facility to the sand collecting pit 4A, and is particularly suitable for a dry sand settling basin. In addition, in the following description, about the element which shows the structure and effect | action substantially the same as sand collection equipment 2A which concerns on 1st Embodiment, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.
[0055]
The sand collection facility 2B includes a sand collection pit 4A formed at one end of the pond bottom 21 of the sand collection basin 1B, and a pond bottom (corresponding to a sand collection channel) of the sand collection basin 1B inclined downward toward the sand collection pit 4A. ) 21, a temporary storage tank 3 for storing a part of the inflow raw water, a discharge device (discharge port) 120 installed laterally on the raw water inflow side, and a control for controlling retention / release of sewage in the temporary storage tank 3 Means (not shown) are the main components.
[0056]
The stored water discharged from the discharge device 120 flows through the pond bottom 21 and reaches the sand collecting pit 4A. By this flow, the sand is sent to the sand collecting pit 4A and discharged by the sand raising device 5A.
[0057]
Incidentally, reference numeral 6A in FIG. 5 is a turbulent flow forming portion, but as described in detail in the first embodiment, instead of this turbulent flow forming portion 6A, another form of turbulent flow forming portion is adopted. But of course.
[0058]
In this sand collection facility 2B, as shown in FIG. 6, a temporary storage tank 3 is attached to the outside of the side wall 11, and a pipe 114 having a trap portion (not shown) is provided below the temporary storage tank 3. A discharge device 120 is connected. The trap portion is for preventing air from entering the storage tank 32 from the discharge port (discharge device 120 in this case) side. If possible, the trap part can be omitted. Hereinafter, the discharge device 120 will be described in detail.
[0059]
The discharge device 120 is provided at the upstream end of the basin 21 of the sand basin 1B, and discharges water to wash away the sand deposited on the bottom surface of the sand basin 1B. In this case, the bottom of the sand basin 1B is partitioned into a plurality of water channels 116 by partition walls 115 parallel to the flow direction of the raw water. The ends of these water channels 116 are respectively connected to the sand collecting pit 4A. The discharge device 120 is disposed so as to cross all the water channels 116, and is configured to selectively open and close the discharge ports 124 provided for the respective water channels 116.
[0060]
As shown in FIGS. 7 to 10, the discharge device 120 includes a fixed pipe 121 that is horizontally disposed so as to cross the above-described all water channels 116, and is rotatably inserted into the fixed pipe 121. It consists of a movable tube 122 into which stored water is introduced, and a rotating device 123 that rotates the movable tube 122.
[0061]
The fixed pipe 121 and the movable pipe 122 are made of metal pipes with different diameters (stainless steel pipes or the like). As shown in FIGS. 8 and 9, each pipe wall has a slot-shaped outlet corresponding to each water channel 116. 124 and 125 are provided. Here, the outlets 124 of the fixed pipe 121 are formed in a horizontal row with their circumferential positions aligned. Further, each outlet 125 of the movable tube 122 is formed such that the position in the axial direction corresponds to the outlet 124 of the fixed tube 121 while sequentially shifting the circumferential position.
[0062]
As a result, the outlets 124 and 125 of the fixed pipe 121 and the movable pipe 122 are selectively communicated with each other according to the rotational position of the movable pipe 122. In other words, only the outlets 124 and 125 corresponding to one water channel 116 are opened and the others are closed depending on the rotational position of the movable tube 122.
[0063]
In the gap between the fixed tube 121 and the movable tube 122, a sealing material 126 is interposed in a range shown by hatching in FIG. The sealing material 126 is disposed so as to surround the outlet 125 of the movable tube 122, and prevents water from leaking from the outlets 124, 125 other than the outlets 124, 125 that are in communication with each other. In addition, as the sealing material 126, what processed soft pipes, such as a vinyl chloride pipe, can be used.
[0064]
As shown in FIG. 6, the movable tube 122 is rotatably supported by bearings 127 at both ends protruding from the fixed tube 121, and one end of the movable tube 122 is the end of the pipe 114 connected to the storage tank 3. In addition, as shown in FIG. 10, it is rotatably connected via a seal mechanism 128. Further, the other end of the movable tube 122 is closed with an end plate 129.
[0065]
As shown in FIG. 11, a gear 131 is provided at the end of the movable tube 121 as an element constituting the rotating device 123 that rotates the movable tube 122, and a worm 133 that meshes with the gear 131 has a vertical axis. As shown in FIG. 6, a motor 134 is installed on the ground as means for rotating the vertical shaft 132 provided at the lower end of 132. When the motor 134 is driven, the worm 133 provided on the vertical shaft 132 rotates in the arrow J direction in the drawing, and the movable tube 122 integrated with the gear 131 meshing with the worm 133 rotates in the arrow K direction. ing.
[0066]
Next, a sand collection method using the sand collection facility 2B will be described.
The settling basin 1B assumes a dry settling basin, and is normally in a dry state. When the inflow of sewage increases during rainwater, sewage flows into the sand basin 1B. Initially, the vacuum release valve 38 and the discharge device 120 (discharge port) are open, and sewage flows into the storage tank 32 through the discharge device 120.
[0067]
Basically, raw water flows into the storage tank 32 until the water level D is the same as that of the sand basin 1B. However, since this height is insufficient, the vacuum release valve 38 is closed by a command from the control means, and the vacuum pump 36 Is driven to draw sewage into the storage tank 32. When the water level reaches a predetermined level, the suction valve 34 is closed by the action of the float valve 35 and the suction by the vacuum pump 36 is stopped.
[0068]
When the rainfall is finished and the water level of the sand basin 1B is, for example, E or less, the discharge device 120 is opened and the stored water is discharged. At this time, the vacuum release valve 38 is kept open. When the stored water flows through the pond bottom 21 toward the sand collecting pit 4A, the accumulated sand S is also washed away to collect the sand.
[0069]
In this case, when the discharge device 120 is repeatedly opened and closed, and the discharge and stop of the stored water are repeated to cause pulsation in the discharge flow, the sand S is effectively collected in the sand collecting pit 4A by the resulting pulsation wave W. be able to.
[0070]
At the time of the discharge, the movable pipe 122 of the discharge device 120 is rotated and the discharge port 124 is opened in order, whereby the discharge is performed individually for each water channel 116 as shown by an arrow M in FIG. Unlike the simultaneous discharge from all outlets 124, the flushing operation can be performed effectively while effectively utilizing the stored water without reducing the momentum of the water given by the potential energy of the stored water. .
[0071]
When such a discharge device 120 is used, since the discharge port 124 provided for each water channel 116 can be selectively opened and closed by the combination of the fixed tube 121 and the movable tube 122, the structure is simple, It can be realized at low cost.
[0072]
In addition, in the sand collection facilities 2A and 2B of each of the above embodiments, it is assumed that the level of sewage flowing into the rainwater reservoir 1A and the sedimentation basin 1B is insufficient for the amount of discharge for sand collection. Although the vacuum forming facility 33 is provided, the vacuum forming facility 33 is not necessarily provided depending on the capacity of the rainwater reservoir 1A and the sand basin 1B. In that case, specifically, the upper part of the storage tank 32 is configured so that the atmosphere can freely enter and exit, and the discharge port 31 and the discharge device 120 are closed when sewage flows into the storage tank 32 from the sand basin 1B. So that the stored water can be retained. By doing so, when collecting sand after that, the stored water can be discharged by opening the outlet 31 and the outlet device 120.
[0073]
【The invention's effect】
As described above, according to the sand collection method and sand collection facility of the present invention, the sediment settling in the storage pond can be swept into the sand collection pit by holding and discharging the stored water. In particular, as the stored water to be discharged, a part of the sewage flowing into the storage pond is stored and retained in advance, and at the time of sand collection, it is simply discharged from the upper part of the gradient in the sand collection channel. Sand collection can be performed efficiently while minimizing running costs.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing a sand collecting facility according to a first embodiment of the present invention.
FIG. 2 is a sectional side view of the sand collecting facility.
FIG. 3 is a plan view showing a configuration of a turbulent flow forming unit for forming a turbulent flow in the flow of water discharged from the sand collecting facility.
FIG. 4 is a plan view showing a plurality of examples of a turbulent flow forming unit.
FIG. 5 is a schematic perspective view showing a sand collecting facility according to a second embodiment of the present invention.
6 is a front view of the discharge device of FIG. 5. FIG.
FIG. 7 is a perspective view showing a schematic configuration of the discharge device.
FIG. 8 is an exploded perspective view showing a schematic configuration of the discharge device.
9 is a cross-sectional view taken along arrow IX-IX in FIG.
10 is a detailed cross-sectional view of a portion X in FIG.
11 is a cross-sectional view of the XI portion in FIG. 6;
[Explanation of symbols]
1A Rainwater Reservoir (Reservoir)
1B Settling basin (reservoir)
11 Side wall
2A, 2B Sand collection facility
21 pond bottom
3 Temporary storage tank
31 Discharge port
31a opening
31b Trap part
32 Storage tank
33 Vacuum forming equipment (supply / discharge means)
34 Suction tube
35 Float valve
36 Vacuum pump
37 Air inlet pipe
37 Vacuum release valve
4 Drainage pit (sand collection pit)
41 trough (sand collection pit)
4A Sand collection pit
5 Transfer pump equipment
6A, 6B, 6C Turbulence forming part
61a, 61b, 61c side
120 Discharge device
α, β, γ vertical angle

Claims (8)

In a storage pond having a sand collection channel having a downward slope toward a sand collection pit formed at the bottom of the pond, a sand collection method for collecting sand accumulated in the storage pond in the sand collection pit,
A part of the sewage flowing into the reservoir is stored and retained in a storage tank adjacent to the reservoir when the sewage flows in, and the stored water is discharged from the upper part of the gradient in the sand collecting channel when the water level of the reservoir decreases. The sand collecting method is characterized in that sand accumulated on the bottom of the reservoir is collected in the sand collecting pit by a discharge flow of the stored water toward the sand collecting pit. The sand collecting method according to claim 1,
A sand collection method characterized by causing the discharge flow to pulsate by repeatedly releasing and stopping the stored water, and collecting sand accumulated in the storage pond by the pulsation in a sand collection pit. A sand collecting pit formed at the bottom of the reservoir where sedimentary sedimentation sand flows down, and a sand collecting channel formed at the bottom of the reservoir and having a downward slope toward the sand collecting pit, A temporary storage tank for storing a part of the inflowing sewage, a discharge port that is disposed upstream of the sand collecting channel and discharges the stored water in the temporary storage tank, and holding of the stored water in the temporary storage tank -Controlling the release, maintaining the state in which the stored water is stored at the time of holding, and a control means for releasing the stored water from the discharge port at the time of release, the sand that settles and deposits in the reservoir by the release of the stored water A sand collection facility that is configured to accumulate in the sand collection pit. The sand collecting facility according to claim 3,
The temporary storage tank is a sealed storage tank whose upper end is closed and whose lower end communicates with the discharge port via a trap portion, and supply / discharge means for supplying and discharging air to and from the upper sealed space in the storage tank And the control means controls the supply and discharge means to draw sewage into the storage tank and to hold and release the sewage. Facility. The sand collecting facility according to claim 3 or 4,
A sand collecting facility characterized in that a turbulent flow forming portion is disposed in the sand collecting channel. The sand collecting facility according to claim 5,
The sand collecting facility, wherein the turbulent flow forming portion is composed of any one of a plate-like body, a cylindrical body, and a triangular prism body installed in an upright state, or a plurality, or a plurality of combinations of each kind. . The sand collecting facility according to claim 6,
The turbulent flow forming portion is composed of a triangular prism body installed in an upright state, and one of the side surfaces of the triangular prism body is abutted and fixed to the side wall of the sand collecting flow path, and on the upstream side of the apex angle of the triangular cross section. A sand collecting facility, wherein the apex angle is set to be equal to or greater than the apex angle located on the downstream side. The sand collecting facility according to claim 7,
A sand collecting facility, wherein a plurality of the turbulent flow forming portions are alternately arranged on the left and right side walls of the sand collecting channel along the discharge flow.

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