JP5903713B2 - Sand collection device for sand basin - Google Patents

Description

  The present invention relates to a sand collecting device that collects sediment deposited in a sand basin of a sewage treatment facility in a sand collecting pit provided in the sand basin by a low pressure sand collecting method.

A sand collecting device that collects the earth and sand settled in a sand basin in a sand collecting pit provided in the sand basin by a low pressure sand collecting method is disclosed in Patent Document 1.
This sand collecting device discharges low pressure water of less than 3kg / cm2 from a number of nozzles installed along the side wall of the sand basin while draining the water in the sand basin and deposits on the bottom of the sand basin. The collected earth and sand are collected in a sand collection pit provided at the bottom of the sand basin.
The earth and sand collected in the sand collection pit is pumped together with water by a sand pump installed in the sand collection pit and transferred to the sewage settling basin.

  Reduces the load on the water supply pump that supplies water to the nozzles installed along the side walls of the sand basin and the sand pump that pumps earth and sand from the sand collection pit, enabling the use of small pumps for the water supply pump and the sand pump. Therefore, the bottom surface of the sand basin is divided into a plurality of areas, and in each area, a nozzle header is installed along the side wall of the sand basin with a number of nozzles attached to the mother pipe at a predetermined interval. Through the control of the sand collecting valve, each nozzle header is sequentially supplied for a predetermined time. The sand collecting valve is configured by directly connecting a flow rate adjusting valve for manually adjusting the flow rate and a switching valve including an automatic valve for switching between water flow and water stop.

  In order to reduce the manufacturing cost and the mounting cost of the nozzle header, all the equal length nozzle headers having the same number of nozzles are installed in an area of the same area.

A water supply pump having a discharge rate of 2 m @ 3 / min is used. When a nozzle with a discharge amount of 0.15 m 3 / min is used, the maximum number of nozzles that can be attached to one nozzle header is 13. However, in order to uniformly discharge water from all nozzles attached to the nozzle header, the number of nozzles must be an even number, so the maximum number that can be attached is twelve. On the other hand, in order to increase the sediment removal efficiency by discharging to the bottom surface of the sand basin, the nozzle mounting interval of the nozzle header is suitably 500 mm. Therefore, the total length of the nozzle header is 6 m at the maximum.

  For example, when the bottom surface of a sand basin having a total length of 18000 mm is divided into a plurality of equal area regions and a nozzle header as long as possible within 6 m is installed in each region, as shown in FIG. When the width dimension of a surface 8b that slopes downward from the side walls Wa and Wb on both sides of the sand collecting pit 7 to the bottom center of the sand basin 1 (hereinafter referred to as a sand collecting pit inclined surface) is 1200 mm, Since the remaining length of the bottom surface on the upstream side and the downstream side of the sand collecting pit inclined surface 8b is 8400 mm, respectively, conventionally, the entire bottom surface of the sand basin is respectively on both the upstream side and the downstream side of the sand collecting pit inclined surface 8b. Each of the two areas was divided into a total of eight equal area areas B1 to B8, and the length of one area was 4200 mm.

  Therefore, the length of the nozzle header NH that can be installed in one region is 4200 mm, and the maximum number of nozzles installed in the nozzle header is 8. That is, conventionally, a sand basin having a total length of 18 m is divided into 8 regions, and 8 nozzle headers (NH1 to NH8) having a length of 4200 mm and 8 nozzles are installed.

Japanese Patent No. 3315489

  As described above, in the sand basin according to the prior art, the bottom surface is divided so that the entire area is equal on both sides of the sand collecting pit inclined surface 8b. Therefore, the number of nozzle headers installed, and therefore the sand collecting valve Since the number of use of the device increases, there is a problem that the equipment cost and the maintenance cost are high. Moreover, since the number of nozzles of one nozzle header is small, there is a problem that the capacity of the water supply pump is not fully utilized.

  This invention is made | formed in view of the said situation, and aims at enabling reduction of the number of sand collecting valves installation in the sand collecting apparatus which uses the water supply pump of the same capability with a sand basin with the same length. .

In order to achieve the above object, the present invention divides the bottom surface of the sand basin into a plurality of regions, and installs a nozzle header in which a number of nozzles are attached at predetermined intervals along each sidewall of the sand basin, By sequentially supplying water from the water supply pump to each nozzle header through the control of the sand collecting valve in the state of drainage in the sand basin, the sediment deposited in each area is formed on the bottom of the sand basin parallel to the direction of the water flow in the sand basin. In the sand collecting device that flows into the trapped trough and collects in the sand collecting pit formed at the bottom of the sand basin through the trough, A plurality of regions are formed by equally dividing in the direction of water flow in the sand basin until the end, and (b) from one side of the sand basin to the bottom of the sand collecting pit provided at the bottom of the sand basin Going down To form a collecting sand pit inclined surface obliquely, characterized in that it has an equal number and equally spaced nozzles each nozzle header installed in all regions (c). (D) It is desirable to make the intervals of all the nozzles of the nozzle header arranged along the side wall equal.

  The sand collecting pit is preferably provided at the center in the longitudinal direction of the sand basin.

According to the present invention, it is possible to reduce the number of nozzle headers used, the number of sand collecting valves installed, and the manufacturing cost of the nozzle headers. That is, it is possible to reduce the number of nozzle headers and sand collecting valves installed, as compared with the conventional case in which regions of equal area are formed on the upstream side and the downstream side of the sand collecting pit inclined surface. Therefore, when sand collection is performed using a water supply pump having the same capacity in the same length of sand, etc., the facility cost and the maintenance cost can be reduced as compared with the conventional one.

  In addition, since some of the nozzles of the nozzle header installed in the area existing across the sand collection pit slope surface spray water toward the sand collection pit slope surface, a dedicated nozzle for the sand collection pit slope surface There is no need to install a sand collection valve. Therefore, the equipment cost and the maintenance cost can be further reduced. However, when using conventional nozzles that spray water on the sand collection pit slope, the spray water from some nozzles of the nozzles of the nozzle header is used for the sand collection pit slope by the jet water from the conventional nozzle. This is preferable because it facilitates sand collection into the sand collection pit.

It is a longitudinal cross-sectional view of the rainwater treatment facility including a sand basin. FIG. 2 is a partially omitted plan view of a range of XX in FIG. 1. FIG. 3 is a cross-sectional view taken along line Y1-Y1 of FIG. FIG. 3 is a sectional view taken along line Y2-Y2 of FIG. It is a top view which mainly shows the distribution of the area | region of a sand basin of FIG. 2, and the installation state of a nozzle header. FIG. 3 is a sectional view taken along line Y3-Y3 of FIG. It is a front view which shows an example of a nozzle header. It is a water supply system diagram concerning an embodiment. It is a flowchart explaining the procedure of sand collection valve control. It is a top view which shows the distribution of the area | region of the conventional sand basin, and the installation state of a nozzle header.

Next, embodiments of the present invention will be described with reference to the drawings.
In FIG. 1, 1 is a sewage treatment facility, which has a sand basin 2 and a pump well 3 formed between side walls Wa and Wb (see FIG. 2). The settling basin 2 is connected to an inflow trough 4 from which sewage such as rainwater and sewage is collected from a sewage pipe not shown. A dam device 5 for allowing or preventing the inflow of sewage from the inflow trough 4 to the sand basin 2 is installed at the downstream end of the inflow trough 4. A contaminant capturing screen 6 is installed immediately before the upstream end of the screen.

  As described above, the bottom surface 2a of the sand basin 2 is inclined so that the center is the deepest, and a sand collection pit 7 is formed at the center, and the width of the bottom of the sand basin is set. A main trough 8a (corresponding to the trough as referred to in the present invention) is formed in the center of the direction so as to incline downward from the upstream end and downstream end of the sand basin to the sand collecting pit 7, and from the lower ends of the side walls Wa and Wb. A surface inclined downward to the sand collecting pit 7 (hereinafter referred to as a sand collecting pit inclined surface) 8b is formed, and the bottom surface of the sand basin is perpendicular to the water flow direction in the sand basin from the vicinity of the side walls Wa and Wb to the main trough 8a. A large number of small troughs 8c extending in parallel with each other are formed.

Further, the bottom surface of the sand basin 2 is divided into odd areas of approximately equal areas by dividing the total length of the sand basin by an odd number on both sides of the main trough 8a, and the entire sand basin is divided into even areas. Yes. 2 and 5, the entire length is divided into three equal parts, and the entire sand basin is divided into six regions B1 to B6.
However, depending on the scale or width of the sand basin 2, the main trough 8a may be formed at a position close to one side wall. In this case, the area of the sand basin becomes an odd number. In any case, the central region (B1, B2) in the longitudinal direction of the sand basin exists across the sand collection pit inclined surface 8b in the center of the sand basin 2.

  Further, nozzles 9a and 9a 'are installed at the upper end of the main trough 8a and the upper end of the sand collecting pit inclined surface 8b, and a large number of nozzles 9b (see FIG. 6) along the side walls Wa and Wb of the regions B1 to B6. Is installed. Furthermore, a nozzle 9c for agitating the earth and sand collected in the sand collecting pit 7 is installed.

A plurality of nozzles 9b installed in the regions B1 to B6 are installed on the nozzle headers NH1 to NH6 installed in the vicinity of the side walls Wa and Wb of the regions B1 to B6. Nozzle header NH1~NH6 shown in FIG. 6, as shown in detail in FIG. 7, is constituted by attaching a plurality of nozzles 9b at equal intervals in the main pipe 11 having a branch pipe 10. Since the length of the sedimentation basin 2 is 18 m and the length of each section area is 6 m, the nozzle headers NH1 to NH6 are all 6 m in length and 12 nozzles (6000 mm / nozzle mounting interval 500 mm). 9b are attached at equal intervals. In the preferred embodiment, as shown in FIGS. 2 and 8, the intervals between all the nozzle headers NH3, NH1, NH5; NH4, NH2, NH6 arranged along each side wall are equal. It is an interval.

  In the example shown in FIG. 5, equal-length nozzle headers NH <b> 1 to NH <b> 6 are installed near the side walls of the six regions B <b> 1 to B <b> 6. The central regions B1 and B2 exist on both sides of the sand collecting pit inclined surface 8b, but the length is the same as the other regions B3 to B6. Therefore, the same nozzle header NH illustrated in FIGS. 6 and 7 is installed in all the regions B1 to B6.

  In that case, some of the nozzles 9b existing in the center of the nozzle headers NH1 and NH2 in the regions B1 and B2 are installed to face the sand collecting pit inclined surface 8b. When the amount of sediment is particularly large, a large amount of sediment may flow from the areas B1 and B2 into the sand collecting pit inclined surface 8b, so that the spray water from some of the central nozzles 9b is from the nozzle 9a '. This is preferable because the collection of sand into the sand collecting pit of the earth and sand flowing on the inclined surface 8b of the sand collecting pit is promoted.

  In the pump well 3, a drainage pump P 1 and a water supply pump P 2 that also serves as a staying water pump are installed, and a sand pump P 3 is installed in the sand collecting pit 7. F of FIG. 1 is a filter installed at the downstream end of the sand basin 2.

  As illustrated in FIG. 6, sand collecting valve groups VG1, VG2 for supplying water from the water supply pump P2 of the pump well 3 to the nozzles 9a, 9a ′, 9b, 9c and stopping the supply thereof. That is, the trough sand collecting valves Va1, Va2, Va3, the nozzle header sand collecting valves Vb1 to Vb6, and the sand collecting nozzle sand collecting valve Vc are provided. As illustrated in FIG. 6, when the bottom surface of the sand basin is divided into six regions (B1 to B6), six nozzle header sand collecting valves Vb (Vb1 to Vb6) are used. Each sand collecting valve is directly connected to a flow rate adjusting valve and a switching valve in the same manner as a conventional sand collecting valve.

  The sand collecting valve groups VG1, VG2, that is, the sand collecting valves Va1, Va2, Va3 for trough, the sand collecting valves Vb1 to Vb6 for the nozzle header, and the sand collecting valve Vc for the earth and sand stirring nozzle will be described later. The opening operation or the closing operation is driven in a predetermined order by the sand collecting valve control circuit of the control device.

  FIG. 8 is a diagram showing the arrangement of the sand collecting valve groups VG1 and VG2 and the water supply system corresponding to the nozzle arrangement of FIG. In the figure, water mixed with earth and sand pumped up from the sand pump P3 is transferred to the sewage sand settling basin 14 after the sand is separated by the sand settling separator 13. The relief circuit 12 coupled to the water supply pump P2 is connected to the sand basin 2 via a sand collecting valve Vd.

  The control device for the sand collecting device includes a water supply pump control circuit, a sand pump control circuit, and a sand collecting valve control circuit.

  The sand collecting pit 7 has a high water level sensor that detects that the water level in the sand collecting pit has exceeded a predetermined high water level, and the water level in the sand collecting pit has a predetermined low water level. And a low water level sensor for detecting this.

  When activated, the sand pump control circuit starts the automatic operation mode of the sand pump P3. When it detects that the high water level sensor has become higher than the high water level, it starts the operation of the sand pump P3. When the low water level sensor detects that the water level is low, the operation of the sand pump P3 is stopped, and when the series of sand collecting valve control by the sand collecting valve control circuit is completed, the automatic operation of the sand pump P3 is performed. The operation mode is canceled.

  The sand collecting valve control circuit opens the sand collecting valve groups VG1, VG2, that is, the trough sand collecting valve Va, the nozzle header sand collecting valve Vb, and the sand collecting nozzle sand collecting valve Vc in a predetermined order. Or it is a closed operation.

  Next, the operation of the above configuration will be described. As shown in FIG. 1, when the dam device 5 is opened, the sewage W flows into the sand basin 2 and further into the pump well 3, and when the water level reaches a predetermined height L1, the drainage pump P1. Is operated, the water in the pump well 3 is pumped up and transferred to a terminal treatment plant or the like outside the figure.

  During the transfer, earth and sand are precipitated from the sewage mixed with the earth and sand flowing into the sand basin 2 and deposited on the bottom 2a of the sand basin. When the accumulation amount reaches a predetermined value, the dam device 5 is closed. When the water level of the settling basin 2 and the pump well 3 is lowered by the drainage by the drainage pump P1 and reaches a predetermined water level L2 equal to the upper surface of the weir provided between the settling basin 2 and the pump well 3, the operation of the drainage pump P1 is performed. Is stopped.

  When the water level of the pump well 3 reaches a predetermined water level L2, the control device activates the feed water pump control circuit, the sand pump control circuit, and the sand collecting valve control circuit.

  Initially, since the water level in the sand collection pit of the sand basin is higher than the high water level, the activated sand pump control circuit starts the automatic operation mode of the sand pump P3. Then, the operation of the sand pump P3 is started. Accordingly, since the earth and sand in the sand collection pit is sucked up by the sand pump P3, the water level in the sand collection pit starts to decrease.

  On the other hand, the activated sand collecting valve control circuit first opens the sand collecting valve Vd of the relief circuit 12 and prepares to drive the water supply pump P2 (step S21 in FIG. 9). Subsequently, after opening the sand collecting valve Va (Va1 to Va3) for the nozzle (S22), the sand collecting valve Vd of the relief circuit 12 is closed (S23), so that water from the water supply pump P2 is fed from the nozzles 9a and 9a ′. It is ejected to the main trough 8a and the sand collecting pit inclined surface 8b. Thereby, the earth and sand in the main trough and the sand collecting pit inclined surface are flowed toward the sand collecting pit 7 together with water. Accordingly, the water level in the sand collecting pit that has started to drop temporarily rises, but since the operation of the sand pump P3 continues, it starts to drop again.

  When the water level in the sand collection pit has dropped to a predetermined water level (Y in S24), that is, when the water level has fallen to a level between the predetermined high water level and a predetermined low water level, The order x of the nozzle header sand collecting valve Vb to be opened among the header sand collecting valves Vb is set to “1”. First, the nozzle header sand collecting valve Vb1 in the first region B1 on the bottom surface of the sand basin is set. Open (S25).

  At this time, ejection from the nozzles 9a, 9a 'to the main trough 8a and the sand collecting pit inclined surface 8b continues. Therefore, in this case as well, the water level in the sand collecting pit that has started to drop temporarily rises, but since the operation of the sand pump P3 continues, it starts to drop again.

  When a predetermined time T has elapsed since that time (Y in S26), the nozzle header sand collecting valve Vbx, that is, the nozzle header sand collecting valve Vb1 in the first region B1 is closed, The order x is set to “x + 1”, and the nozzle header sand collecting valve in the next order area, that is, the nozzle header sand collecting valve Vb2 in the second area B1 is opened (S27).

At that time, it is checked whether or not “x + 1” is the last rank of the area, that is, 6 (S28). If it is not the last rank, the process returns to step S26, and the nozzle header sand collecting valve in the rank area at that time is turned on. At the same time as closing, the nozzle header sand collecting valve in the next rank region is opened (S27).
Each time the nozzle header sand collecting valve Vb of each region is opened, the water level in the sand collecting pit, which has started to decrease, is repeatedly raised and then lowered again.

  In step S27, when the nozzle header sand collecting valve in the last rank area, that is, the nozzle header sand collecting valve Vb6 in the sixth area B6 is opened (Y in S28), a predetermined time T has elapsed. (When Y in S29), the sand collecting valve Vd of the relief circuit 13 is opened and the nozzle header sand collecting valve Vb6 in the last region, that is, the nozzle header sand collecting valve Vb6 in the sixth region B6 is opened. The nozzle sand collecting valve Va is closed (S210).

  After that, the water level in the sand collecting pit is lowered to a predetermined low water level, so the sand pump is stopped. Thereby, a series of sand collection operation | movement and sand removal operation | movement are complete | finished. When this series of sand collecting operation and sand removal operation is completed, the automatic operation mode of the sand pump is canceled.

  In the example shown in FIG. 6 and FIG. 8, it is installed in the first region B1 and the second region B2 that exist across the both sides of the sand collecting pit inclined surface 8b, that is, the region that exists in the center in the longitudinal direction of the sand basin. In addition, the nozzle 9b existing in the central portion of the nozzle headers NH1 and NH2 faces the sand collecting pit inclined surface 8b. Since the sand collecting pit inclined surface 8b is adjacent to the deepest position of the inclined bottom surface of the sand basin, a relatively large amount of earth and sand flows from the bottom surface into the sand collecting pit inclined surface 8b. Accordingly, the water sprayed from the nozzle in the central portion promotes the flow of the earth and sand on the sand collecting pit inclined surface 8b toward the sand collecting pit side by the nozzle 9a '. In the case of a sand basin with a small amount of sediment flowing into the sand collection pit inclined surface 8b, the nozzle 9a 'of the sand collection pit inclined surface 8b can be omitted. Therefore, in this case, the sand collecting valve for the nozzle 9a 'can be reduced.

DESCRIPTION OF SYMBOLS 1 Rainwater treatment equipment 2 Settling basin 2a Bottom of settling basin 3 Pump well 7 Sand collection pit 8a Main trough 8b Sand collection pit inclined surface 8c Small trough B1-B6 area 9a Nozzle of main trough 9a 'Nozzle of sand collection pit inclined surface 9b Nozzle header nozzles NH1-NH6 Nozzle header P1 Drainage pump P2 Water supply pump P3 Sand pump

Claims (2)

The bottom surface of the sand basin is divided into a plurality of areas, and nozzle headers are installed along the sidewalls of the sand basin with a number of nozzles attached at predetermined intervals in each area. By sequentially supplying water to each nozzle header through the control of the valve, the sediment deposited in each region flows to the trough formed in the bottom of the settling basin in parallel with the direction of water flow in the settling basin, and passes through the trough. In the sand collection device that collects in the sand collection pit formed at the bottom of the sand basin,
A plurality of regions are formed by equally dividing the bottom surface of the sand basin in the direction of water flow in the sand basin between the upstream end of the sand basin and the downstream end on at least one side of the trough,
Forming a sand collection pit inclined surface that slopes downward from the side wall of the sand basin to the bottom surface of the sand collection pit provided at the bottom of the sand basin in one region thereof,
1. A sand collecting device characterized in that the nozzles of the nozzle header installed in all areas are equal in number and at equal intervals. 2. The sand collecting apparatus according to claim 1, wherein all nozzles of all nozzle headers arranged side by side along the side wall are equally spaced .

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