JP2011245389A - Method and apparatus for removing sand in settling basin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sand removing method which prevents a sand pump from being buried in earth and sand collected in a sand collecting pit at the beginning of sand removing operation.SOLUTION: In the sand removing method where water is discharged from nozzles installed in a trough of a settling basin and water discharge from nozzles of nozzle headers, provided in regions formed by dividing the bottom surface of the settling basin into a plural number in the water flow direction in the settling basin, is performed to each of the regions in a predetermined order in a state where water is discharged from the settling basin, thereby washing down earth and sand deposited in the regions to the trough to collect them into the sand collecting pit, and the earth and sand collected in the sand collecting pit is pumped and removed by the sand pump installed in the sand collecting pit, water is discharged from the nozzles installed in the trough and at the same time water is discharged from an agitating nozzle installed in the sand collecting pit, and operation of the sand pump is started.

Description

  The present invention relates to a sand removal method for collecting earth and sand deposited in a sand basin of a sewage treatment facility in a sand collecting pit and removing the collected earth and sand by a pump and a sand removal apparatus for using the method.

  Sand collected at the bottom of the sand basin by discharging low pressure water from the nozzle to the bottom of the sand basin while draining the water in the sand basin with a drain pump (draining state) Patent Document 1 discloses a low pressure sand collection type sand removal device that collects sand and sand in the pit, pumps the collected earth and sand together with water by a sand pump installed in the sand collection pit, and transfers it to a sewage settling basin.

  A sand basin that performs low-pressure sand collection by the sand removal device has the following structure. That is, a sand collection pit is formed in a part of the bottom of the sand basin, for example, in the center, and the bottom of the sand basin is inclined so that the periphery of the sand collection pit is deepest, and the bottom of the sand basin A trough that extends in parallel with the water flow direction (hereinafter referred to as the main trough) is formed so that the sand collecting pit side is deep, and in the longitudinal center of the bottom part, it descends from the side walls on both sides of the sand basin to the bottom of the sand collecting pit. In addition, a large number of small troughs extending in parallel to the direction perpendicular to the direction of water flow in the sand basin are formed on the bottom surface of the sand basin.

  In order to perform low-pressure sand collection, a number of nozzles are installed as follows. That is, the nozzles are installed at the upper end of the main trough and the upper end of the sand collecting pit slope, the upper end of the area where the bottom surface of the sand basin is divided into a plurality of sides on both sides of the main trough, and the sand collecting pit. . The nozzles provided at the upper end of the main trough and the upper end of the sand collecting pit inclined surface are hereinafter referred to as trough nozzles. A plurality of nozzles installed in the region are attached to nozzle headers installed along the side wall of the sand basin at equal intervals in each region. The nozzle installed in the sand collection pit is for stirring the earth and sand in the sand collection pit, as will be described later.

  In order to perform low-pressure sand collection, water from the water supply pump installed in the pump well connected downstream of the sand basin is supplied to the nozzle and nozzle header (water flow), A switching valve group for stopping (water stopping), that is, a nozzle switching valve, each nozzle header switching valve, and a stirring nozzle switching valve is provided. And the sand removal apparatus has the switching valve control means which makes the opening / closing switching operation | movement of these each switching valve in a predetermined order.

  In preparation for the sand removal operation, a dam device provided upstream of the settling basin and opened to allow sewage such as rainwater and sewage to enter the settling basin is closed to prevent sewage from entering the settling basin. After that, the operation of the drainage pump installed in the pump well is started, and the water in the sand basin is transferred to the final treatment plant. As a result, when the amount of water in the settling basin and the pump well decreases and the water level reaches a predetermined height, the operation of the drainage pump is stopped. Thereby, the preparation for the sand removal operation is completed.

  Subsequently, when a sand removal operation start command is input to the sand removal device, the automatic operation mode of the sand pump is started. In the automatic operation mode, the water level sensor installed in the sand collection pit is connected to the sand collection pit. When it is detected that the water level inside the water level is higher than the predetermined high water level, the operation is automatically started. When the water level sensor detects that the water level in the sand collecting pit has reached the predetermined low water level, it is automatically operated. It is configured to stop the operation. That is, the sand pump operates so as to maintain the drainage state in which the water surface in the sand basin is located in the sand collection pit.

  Further, based on the sand removal operation start command input, the switching valve is controlled by the switching valve control means. However, conventionally, the control of the sand pump and the control of the switching valve have been performed independently.

  More specifically, when the automatic operation mode of the sand pump is started, the water pump in the sand collection pit starts operation because the water level in the sand collection pit is higher than the high water level. When the water level drops to a predetermined low water level and becomes drained, the sand pump stops operation. Following this, the switching valve control means controls the switching valve as follows. Hereinafter, a case where the bottom surface of the sand basin is divided into four regions will be described as an example.

a) The switching valve control means first opens the nozzle switching valve (sets the water flow state). Thereby, the water from a water supply pump is supplied to a trough nozzle, and water is discharged from those nozzles. When the water discharged from the trough nozzle causes soil and water on the inclined surface of the main trough and sand collecting pit to flow into the sand collecting pit, the sand pump starts operation when the water level in the sand collecting pit becomes higher than the high water level.
b) At the same time as or immediately before the start of the operation of the sand pump, the switching valve control means opens the stirring nozzle switching valve.
c) After the passage of the trough switching valve, the nozzle in the first region at the bottom of the sand basin after a lapse of time Tx required for the earth and sand in the inclined surface of the main trough and sand collecting pit to flow into the sand collecting pit. Open the header switching valve.
d) After the predetermined time T1 has elapsed, the nozzle header switching valve in the first region is closed (water-stopped), and the nozzle header switching valve in the second region is opened.
e) After the elapse of the predetermined time T2, the nozzle header switching valve in the second region is closed and the nozzle header switching valve in the third region is opened.
f) After the predetermined time T3 has elapsed, the nozzle header switching valve in the third region is closed and the nozzle header switching valve in the fourth region is opened.
g) After the elapse of the predetermined time T4, the nozzle header switching valve in the fourth region is closed and the trough switching valve is closed.
The fixed times T1 to T4 are times necessary for flowing the sediment accumulation amount in the region.

  After closing the nozzle header switching valve in the fourth zone, the water in the sand basin flows into the sand collecting pit and the sand basin is drained, that is, when the water level sensor detects a low water level. The sand pump stops operating. Thereby, a series of sand removal operations is completed. When this series of sand removal operations is completed, the automatic operation mode of the sand pump is canceled.

Japanese Patent No. 3315489

  As described above, in the conventional sand removal apparatus, the earth and water in the inclined surface of the main trough and the sand collection pit flow into the sand collection pit due to water discharged from the trough nozzle, and the water surface in the sand collection pit exceeds the high water level. Then, the sand pump started operation, and at the same time or just before that, water discharge from the stirring nozzle was started. However, since the largest amount of earth and sand is likely to collect in the sand collection pit at the beginning of water discharge from the trough nozzle, when the sand pump starts operation when the water level in the sand collection pit becomes higher than the high water level, There was a risk of being unable to remove sand due to being buried in the earth and sand.

  The present invention has been made in view of the above circumstances, and provides a sand removal method in which a sand pump is prevented from being buried in earth and sand collected in a sand collection pit at the beginning of the sand removal operation. The purpose. A second object is to provide a sand removal apparatus for using the method.

  In order to achieve the first object, the present invention discharges water from a trough nozzle of a drained sand settling basin and discharges water from a nozzle of a nozzle header provided in a region formed by dividing the bottom surface of the sand basin into a plurality of areas. A sand pump installed in the sand collecting pit, which is carried out in a predetermined order every time, and the earth and sand accumulated in the area flows into the main trough and is further collected in the sand collecting pit. In the sand removal method, the water is discharged from the trough nozzle and simultaneously discharged from the stirring nozzle installed in the sand collecting pit, and the operation of the sand pump is started (Claim 1).

In order to achieve the second object, the present invention provides a sand basin, (in this case, the sand basin is inclined so that a part of the bottom of the sand basin is deep, and a part of the bottom A sand collection pit formed, a main trough formed between the side walls on both sides of the sand settling basin so that the sand collection pit side is deep in parallel with the water flow direction in the sand settling basin, and the sand collection pit inclined surface. A), a drainage pump installed in a pump well connected to the sand basin, a sand pump installed in the sand collection pit, a sand pump control means for controlling the sand pump, and the sand collection A water level detecting means for detecting and outputting the water level of the water surface in the pit, a nozzle (trough nozzle) installed at the upper end of the main trough and the upper end of the sand collecting pit inclined surface, and the sand collecting pit Installed stirring nozzle and bottom of the sand basin A plurality of nozzles were attached to each of the regions divided in the direction parallel to the direction of water flow in the sand settling basin on at least one side of the main trough, and installed above the bottom surface near the side wall of the sand basin. Nozzle header, said trough nozzle of water from the water supply pump, a stirring nozzle, a switching valve group for passing and stopping water to each nozzle header, and a switching valve for controlling the switching operation of said switching valve group in a predetermined order A sand removal apparatus comprising a control means,
(A) The sand pump control means starts an automatic operation mode based on a sand collection operation start command input, and when the water level of the sand basin reaches a predetermined level due to drainage by the drain pump, the switching valve control means Opens the trough nozzle switching valve and the stirring nozzle switching valve, and simultaneously starts the operation of the sand pump, stops the operation of the sand pump based on the low water level detection signal from the water level detection means, After closing the nozzle switching valve and the stirring nozzle switching valve of the main trough after the control means closes the nozzle header switching valve in the last order region, the automatic operation mode shall be released.
(B) After the sand removal operation start command is input, the switching valve control means opens the trough nozzle switching valve for a predetermined time and simultaneously opens the stirring nozzle switching valve for a predetermined time, and thereafter, the intermediate valve from the water level detection means Open the nozzle header switching valve in the earliest order area based on the water level detection signal, and thereafter input the intermediate water level detection signal from the water level detection means, until the nozzle header switching valve in the last order area, After closing the nozzle header switching valve that was open corresponding to the region in the order, opening the nozzle header switching valve in the next region, and closing the nozzle header switching valve in the last region, the water level The trough switching valve and the agitation nozzle switching valve are closed based on the input of an intermediate water level detection signal from the detection means (claim 2).

  Each time the switching valve control means inputs an area order designating section for sequentially designating the order of areas where water should be jetted from the nozzle header, and an intermediate water level detection signal from the water level detecting means, A rank determination unit that determines whether or not the rank of the area specified by the designation unit is in the last order, and the trough nozzle switching valve is opened after the sand removal operation start command is input, and the rank determination unit is determined to be in the last order. A first switching valve control unit that closes the trough nozzle switching valve, and a nozzle header switching valve in a region designated by the region ranking designating unit for a predetermined period of time, so that an intermediate water level from the water level detection means And a second switching valve control section that closes the nozzle header switching valve by inputting a detection signal (claim 3).

In order to achieve the second object, the present invention provides a sand basin (in this case, the sand basin is inclined so that a part of the bottom of the sand basin is deepened) A sand collection pit formed in the section, a main trough formed between the side walls on both sides of the sand settling basin so that the sand collection pit side is deep in parallel with the water flow direction in the sand settling basin, and the sand collection pit inclined surface A drainage pump installed in a pump well connected to the sand basin, a sand pump installed in the sand collection pit, a sand pump control means for controlling the sand pump, and the sand collection A water level detecting means for detecting and outputting the water level of the water surface in the pit, a nozzle (trough nozzle) installed at the upper end of the main trough and the upper end of the sand collecting pit inclined surface, and the sand collecting pit Installed stirring nozzle and the sand basin A plurality of nozzles were mounted on the bottom surface of each of the regions divided at least on one side of the main trough in a direction parallel to the direction of water flow in the sand settling basin above the bottom surface near the side wall of the sand settling basin. Nozzle header, nozzles on the inclined surface of the main trough and sand collecting pit of water from the water supply pump, a stirring nozzle, a switching valve group for passing / stopping water to each nozzle header, and a switching operation of the switching valve group A sand removal apparatus having a switching valve control means for controlling the sand pump in a predetermined order. (A) The sand pump control means starts an automatic operation mode based on a sand collection operation start command input, and the drain pump When the water surface of the sand basin reaches a predetermined water level due to the drainage due to, the switching valve control means opens the trough switching valve and the stirring nozzle switching valve and simultaneously starts the operation of the sand pump. The trough switching valve and the stirring nozzle after the operation of the sand pump is stopped based on the low water level detection signal from the water level detection means, and the switching valve control means closes the nozzle header switching valve in the last order region. The automatic operation mode shall be canceled after closing the switching valve for
(B) After the sand removal operation start command is input, the switching valve control means opens the trough nozzle switching valve for a predetermined time and simultaneously opens the stirring nozzle switching valve for a predetermined time, and then the nozzle header in the earliest order region. After the nozzle switching valve is opened for a predetermined time, the nozzle header switching valve is closed. Thereafter, each time the intermediate water level detection signal is input from the water level detection means, the nozzle header switching valve in the last order is sequentially The nozzle header switching valve in the forward region is opened for a predetermined time, and then the nozzle header switching valve is closed (Claim 4).

  Each time the switching valve control means inputs an area order designating section for sequentially designating the order of areas where water should be jetted from the nozzle header, and an intermediate water level detection signal from the water level detecting means, The rank determination unit that determines whether the rank of the area designated by the designation unit is the last order, and the rank determination after the sand removal operation start command is input or when the intermediate water level detection signal is input from the water level detection means After the trough nozzle switching valve is opened for a predetermined period of time when it is determined that the section is not in the last order, the first switching valve control unit that is closed and the nozzle header switching valve in the region where the rank is specified are opened for a predetermined period of time. And a second switching valve control unit that closes (Claim 5).

  According to the method of the present invention, at the beginning of sand collection, water is discharged from the nozzle of the trough and simultaneously water is discharged from the stirring nozzle installed in the sand collection pit, and the operation of the sand pump is started. Since the earth and sand flowing into the sand is fluidized in the sand collecting pit and immediately pumped up by the sand pump, it is prevented that the sand pump is buried in the earth and closed. Therefore, the earth and sand collected from each area of the bottom surface of the sand basin is then smoothly pumped up by the sand pump and removed.

  According to the apparatus of the present invention, the sand removal method of the present invention can be reliably implemented.

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. FIG. 3 is a cross-sectional view taken along line Y3-Y3 of FIG. It is a top view of the periphery of a sand collection pit. It is Z1-Z1 sectional drawing of FIG. It is Z2-Z2 sectional drawing of FIG. It is a water supply system diagram. It is a control system diagram which illustrates the control device in one embodiment. It is sectional drawing which shows the detection water level by the water level sensor of a sand collection pit. It is a flowchart of a sand pump control means. It is a flowchart of a switching valve control means. It is a flowchart of a switching valve control means.

Next, embodiments of the present invention will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a rainwater 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.

  In the pump well 3, a drainage pump P <b> 1 described later and a water supply pump P <b> 2 serving also as a staying water pump are installed, and a sand pump P <b> 3 described later 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.

  A nozzle (trough nozzle) 9a is installed at the upper end of the main trough 8a and the sand collecting pit inclined surface 8b, and the bottom surface of the sand basin is divided into a plurality of water flow directions in the sand basin on both sides of the main trough 8a (FIGS. 2 and 6). Then, the nozzle 9b is installed at the upper end of the area divided into 4 sections (8 sections in total). A plurality of nozzles 9b installed in the regions are installed at equal intervals on the nozzle header NH installed in the vicinity of the side walls Wa and Wb in each region. FIG. 5 shows an example in which nozzle headers NH1, NH2,... Formed by attaching a plurality of water supply nozzles 9b to the mother pipe 10 at a predetermined interval are shown. In the sand collecting pit 7, a sediment stirring nozzle 9c is installed. Sediment mixing nozzles 9c are installed so that a plurality (four in FIG. 2) discharge from two directions opposite to the lower part of the sand pump P3 at a position close to the tangential line around the lower part of the sand pump P3. Has been. In order to simplify the drawing, the earth and sand stirring nozzle 9c is not shown in FIG. 4, and the sand pump P3 is not shown in FIG.

And as illustrated in FIG.5 and FIG.6, the water from the water supply pump P2 of the pump well 3 is supplied (water flow) to each said nozzle 9a, 9b, 9c, or the supply is stopped (water stop). There are provided switching valve groups VG1 and VG2 constituted by electromagnetic valves for performing the above operation, that is, a trough nozzle switching valve Va, each nozzle header switching valve Vb, and a stirring nozzle switching valve Vc. As illustrated in FIGS. 2 and 9, when the bottom surface of the sand basin is divided into eight regions, eight nozzle header switching valves Vb (Vb1 to Vb8) are used.
A relief circuit 11 is provided via a switching valve Vd in the pipeline connecting the water supply pump P2 and the switching valve groups VG1, VG2, and water from the water supply pump P2 when all the switching valves are closed is supplied. It is configured to escape to the sand basin 2.

  As shown in FIG. 10, an operation panel 101 having a sand removal start button (not shown) is added to the control device 100 provided in the sand removal device for carrying out the method of the present invention, and a drain pump control circuit PCON1, A feed water pump control circuit PCON2 and a sand pump control circuit PCON3 are incorporated, and a switching valve control circuit VCON is incorporated.

  As shown in FIG. 10 and as will be described later, the switching valve control circuit VCON includes a block order designation unit 102 for sequentially designating the order of blocks to which water should be injected from the nozzle header, and a block of one order. A rank determining unit 103 for determining whether the block order specified by the block order specifying unit 102 is the last order when the nozzle header switching valve is closed, and controlling the opening / closing of the relief circuit switching valve Vd. Open the first switching valve control unit 104, the second switching valve control unit 105 that controls the opening and closing of the trough nozzle switching valves Va and Vc, and the nozzle header switching valves Vb1 to Vb8 of the blocks in which the ranks are specified. A third switching valve control unit 106 that closes based on an intermediate water level detection signal from the sensor 13, and is arranged in a predetermined order to the group of switching valves Va, Vb, Vc, Vd. In those providing a control signal for driving the opening operation or closing operation.

  Further, the control device 100 is installed in the sand collecting pit 7, and the water level in the sand collecting pit 7 is higher than a predetermined high water level HWL conceptually shown in FIG. 11, any of the intermediate water level MWL and the low water level LWL. The water level sensor 13 (see FIGS. 10 and 11) that detects and outputs whether or not there is an electrical connection is electrically connected.

  The operation of the above configuration will be described. When the dam device 5 is opened, the sewage flows into the sand basin 2 and further into the pump well 3, and when the water level reaches a predetermined height, the drain pump control circuit of the control device 100 of the sand removal device. The drain pump P1 provided in the pump well 3 is operated by PCON1, and 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 surface 2a of the sand basin. When the accumulation amount reaches a predetermined value, the dam device 5 is closed and the inflow of sewage into the sand basin 2 is prevented. And if the water surface of the sand basin 2 and the pump well 3 falls by the drainage by the drainage pump P1 and reaches a predetermined water level (WL in FIG. 1), the drainage pump control circuit PCON1 stops the operation of the drainage pump P1.

  When it is detected that the water level of the pump well 3 has reached a predetermined water level (WL in FIG. 1), the control device 100 activates the feed water pump control circuit PCON2, the sand pump control circuit PCON3, and the switching valve control circuit VCON.

  As shown in FIG. 12, the sand pump control circuit PCON3 starts the automatic operation mode of the sand pump P3 (S11). The operation of the sand pump P3 is not started until the high water level HWL is reached after the operation of the water supply pump P2 is started, that is, until the drainage state is reached. If the sand pump P3 is operated during that time, it is injected from the stirring nozzle, so that the sand is rolled up, enters the pump well, and flows out to the river or the like. A detection signal from the water level sensor 13 checks whether the water level in the sand collection pit 7 is equal to or higher than a predetermined high water level HWL (S12). When the water level is higher than the high water level HWL, the operation of the sand pump P3 is started ( S13).

  Further, as shown in FIG. 13, the switching valve control circuit VCON first opens the relief valve switching valve Vd based on the sand removal operation start command input, and drives the water supply pump P2. Preparation is made (step S21 in FIG. 10). Subsequently, after the second switching valve control unit 105 opens the trough nozzle switching valve Va and the stirring nozzle Vc (S22), the first switching valve control unit 104 closes the switching valve Vd of the relief circuit (S23). Water from the pump P2 is discharged from the trough nozzle 9a to the main trough 8a and the sand collecting pit inclined surface 8b. Thereby, the earth and sand in each trough is poured toward the sand collection pit 7 with water.

  In the embodiment of the present invention, the switching valve control circuit VCON opens the stirring nozzle switching valve Vc at the same time as opening the trough nozzle switching valve Va (S22). At the same time, the sand pump control circuit PCON3 is configured to start operation of the sand pump.

  Since the discharge amount of the sand pump P3 is larger than the discharge amount of the water supply pump P2, the water level in the sand collecting pit 7 is lowered. When the water level sensor 13 detects that the water surface has reached a predetermined intermediate water level (Y in S24), the region rank designation unit 102 of the switching valve control circuit VCON determines the rank of the sand collection target region, for example, +1 Then, since the first region B1 is designated (S25), the third switching valve control unit 106 opens the nozzle header switching valve Vb (b1) in the first region B1 (S26). Water is jetted from the ground, and the earth and sand accumulated in the first region B1 is flowed toward the main trough and further flows into the sand collecting pit 7. Thus, the sewage mixed with the earth and sand collected and stirred in the sand collecting pit 7 is pumped up by the sand pump P3 and transferred to the earth and sand basin. Thereby, although the water surface in the sand collection pit 7 rises temporarily, it falls in time.

  When the water level sensor 13 detects that the water surface has again reached the predetermined intermediate water level (Y in S27), the rank determination unit 103 checks the rank designated at that time, and if it is not the last order, , Returning to S25, the nozzle header switching valve Vb (b2) in the next region is opened (S26), and when it is detected that the water level sensor 13 has reached the predetermined intermediate water level, the third switching valve control unit performs the nozzle switching. The header switching valve Vb (b2) is closed. Then, S25 (order designation) to S28 (closure of the nozzle header switching valve) are repeated until the sand collection target region is in the last order.

  Then, after the sand collecting operation is performed up to the eighth region B8 which is the last region, the first switching is performed when the water level sensor 13 detects that the water level sensor 13 has reached a predetermined low water level (Y in S210). The single control unit 104 or the third switching valve control unit 106 opens the relief circuit switching valve Vd, and closes the trough nozzle switching valve Va, the stirring nozzle switching valve Vc, and the nozzle header switching valve Vb (b8). Then, a series of switching valve control is completed. Further, the feed water pump control circuit PCON2 also stops the operation of the feed water pump P2.

  On the other hand, the sand pump control circuit PCON3 constantly monitors the detection state of the water level sensor 13 from the start of operation of the sand pump P3, and by closing the nozzle header switching valve Vb4 in the fourth region B4, Since the water level in the sand pit 7 falls to the low water level LWL (when S14 is Y), the operation of the sand pump P3 is stopped (S15). Thereafter, the sand pump control circuit PCON3 checks whether or not the control of the switching valve has been completed (S16). If it has not been completed, the process returns to step S12, and the water level becomes high (when Y in S12). Starts the operation of the sand pump P3 again, but after confirming the completion of the switching valve control (Y in S16), cancels the automatic operation mode of the sand pump (S17).

  As described above, the sand pump P3 automatically starts when the water level in the sand collection pit is higher than the predetermined high water level HWL in order to maintain the sand collection pit 7 in a drained state when the automatic operation mode is started. When the water level drops to a predetermined low water level LWL, the operation is automatically stopped. However, in the method of the present invention, the water level in the sand collection pit is set to a predetermined high water level HWL and a predetermined low water level. When the water level LWL drops to the intermediate water level MWL, the nozzle header switching valve in the preceding region is closed and the nozzle header switching valve in the subsequent region is opened up to the last order region. During the switching operation, the water level in the sand collection pit is stopped by the closing operation of the nozzle header switching valve in the preceding region, the pumping of the sand pump is pumped, and the nozzle header switching valve in the subsequent region is stopped. By opening action Although it fluctuates due to the start of water injection, the intermediate water level, which is the temporal reference for the switching operation of the switching valve, is set to a height position where the water level in the sand collection pit does not drop to a predetermined low water level during the switching operation of the switching valve. do it. The height position can be calculated from the injection amount of each trough and each nozzle header, the cross-sectional area of the sand collecting pond, the discharge amount of the sand pump, and the like.

  If an automatic solenoid valve with a fast switching operation is used as the nozzle header switching valve, the water level in the sand collecting pit between the end of the water injection for the preceding region and the start of the water injection for the next region is reduced. Since the amount of decrease can be reduced, the accuracy in setting the intermediate water level is relaxed. Moreover, since the load of the sand pump is stabilized, the life is extended.

  In the above embodiment, the switching valve control circuit VCON sets the opening / closing timing of the nozzle header switching valve in each region based on the fact that the water level sensor 13 detects the intermediate water level. Instead of using the timer provided in the switching valve control circuit VCON, when the predetermined time elapses, the nozzle header switching valve in the preceding region is closed, and then when the water level sensor 13 detects the intermediate water level, It may be controlled to open the nozzle header switching valve in the area. Further, when the trough switching valve Va and the stirring nozzle switching valve Vc are opened for a predetermined time immediately before or simultaneously with the opening of the nozzle header switching valve in each region, the sand collecting efficiency is further improved.

Hereinafter, an embodiment in which a timer and a water level sensor are used will be described.
The switching valve control circuit VCON in this embodiment, as illustrated in FIG. 10 and, as will be described later, a block order designation unit 102 that sequentially designates the order of blocks to which water should be injected from the nozzle header; Each time an intermediate water level detection signal from the post-water level sensor 14 is input, a rank determination unit 103 that determines whether or not the block rank designated by the block rank designation unit 102 is in the last order, and a relief circuit The determination result of the first switching valve control unit 104 that controls the opening / closing of the switching valve Vd and the rank determination unit 103 after the sand removal operation start command is input or when the intermediate water level detection signal is input from the water level sensor 14 is not in the last order. Sometimes, the second switching valve control unit 105 that opens the nozzle switching valves Va and Vc on the inclined surface of the main trough and the sand collecting pit for a predetermined time, and the block in which the order is designated And a third switching valve control unit 106 that opens the nozzle header switching valves Vb1 to Vb8 for a predetermined time, respectively, for driving the group of switching valves Va, Vb, Vc, and Vd to open or close in a predetermined order. The control signal is given.

  As shown in FIG. 14, the switching valve control circuit VCON starts a control program based on a sand removal operation start command input from the operation panel 101, and the first switching valve control unit 104 first switches the relief valve switching valve Vd. To prepare for driving the water supply pump P2 (step S31 in FIG. 15). Subsequently, after the second switching valve control unit 105 opens the trough nozzle switching valve Va and the earth and sand stirring nozzle switching valve Vc (S32), the first timer (not shown) is started (S33), and The one switching valve control unit 104 closes the switching valve Vd of the relief circuit 11 (S33 ′). When the first timer expires, that is, when water from the water supply pump P2 is sprayed from the nozzle 9a to the main trough 8a and the sand collecting pit inclined surface 8b for a predetermined time (Y in S34), the trough nozzle switching valve Va and The switching valve Vc for the earth and sand stirring nozzle is closed (S35). Subsequently, since the block order specifying unit 102 of the switching valve control circuit VCON increments (+1) the order (S36), the third switching valve control unit 106 is the block of the order specified by the block order specifying unit 102, that is, In this case, since the nozzle header switching valve Vb1 of the first block B1 is opened (S37), water is sprayed from each nozzle of the nozzle header NH1, and the earth and sand accumulated in the first block B1 become the main trough 8a. And then flows into the sand collection pit 7. Thus, the sewage mixed with the earth and sand collected and stirred in the sand collecting pit 7 is pumped up by the sand pump P3 and transferred to the sewage sand settling basin 13 through the sand settling separator 11.

  When the nozzle header switching valve Vb1 of the first block B1 is opened, a second timer (not shown) is started, and the time is up after a predetermined time set in advance (Y in S39), the first The nozzle header switching valve Vb1 of the block B1 is closed.

  Since the discharge amount of the sand pump P3 is designed to be larger than the discharge amount of the water supply pump P2, the water surface in the sand collecting pit 7 rises temporarily due to the inflow of water and earth and sand, but eventually decreases. After that, when the water level sensor 14 detects that the water level in the sand collecting pit has reached a predetermined intermediate water level (Y in S311), the rank determining unit 103 of the switching valve control circuit VCON then blocks. It is determined whether or not the order specified in the order specifying unit 102 is the last order (S312).

  If it is not the last order, the process returns to S22, and after the water discharge (S32-S35) for a predetermined time to the main trough 8a and the sand collecting pit inclined surface 8b by the second switching valve control unit 105 is performed, the block order designation unit 102 The next block is designated by (S36), and the switching valve control circuit VCON opens the nozzle header switching valve Vb2 of the second block B2 for a predetermined time and then closes it. When it is detected again by the water level sensor 14 that the water level in the sand collection pit has reached the predetermined intermediate water level, it is then determined whether or not the block order is the last order (S312). That is, until the water injection target block is in the last order, water discharge for a predetermined time (S32-S35) and water discharge for a predetermined time from the nozzle header to the main trough 8a and the sand collecting pit inclined surface 8b from the nozzle 9a for that block ( S37-S310) are repeated. As a result, the earth and sand of all the blocks on the bottom surface of the sand basin are caused to flow along with the water to the main trough 8 a and flow toward the sand collecting pit 7.

  When the rank determining unit 103 determines the last order, that is, the fourth block B4 (Y in S312), the water level sensor 14 detects that the water level in the sand collecting pit has become a predetermined low water level. At (when Y in S313), the first switching valve control unit 104 of the switching valve control circuit VCON performs control to open the switching valve Vd of the relief circuit, and the series of switching valve control is completed. Further, the feed water pump control circuit PCON2 also stops the operation of the feed water pump P2.

DESCRIPTION OF SYMBOLS 1 Rainwater treatment equipment 2 Settling basin 2a Bottom surface of settling basin 3 Pump well 7 Sand collection pit P1 Drainage pump P2 Water supply pump P3 Sand pump 8a Main trough 8b Sand collection pit inclined surface 8c Small trough 9a, 9b, 9c Nozzle NH1-NH8 Nozzle header 13 Water level sensor HWL High water level MWL Intermediate water level LWL Low water level Va, Vb, Vc, Vd selector valve

Claims (5)

With the sand basin drained, water is discharged from the nozzle installed in the trough of the sand basin, and water is discharged from the nozzle of the nozzle header provided in the area where the bottom surface of the sand basin is divided into multiple water flow directions in the sand basin. A sand pump that performs in a predetermined order for each area, causes the sediment accumulated in the area to flow into the trough, collects it in the sand collection pit, and installs the earth and sand collected in the sand collection pit in the sand collection pit In the sand removal method that is pumped up and removed by
A sand removal method for a sand basin characterized by discharging water from a nozzle installed in a trough and simultaneously discharging water from a stirring nozzle installed in a sand collecting pit and starting operation of a sand pump. A settling basin, in this case, the settling basin is a bottom surface inclined so that a part of the bottom of the settling basin is deep, a sand collecting pit formed in a part of the bottom, and a side wall on both sides of the settling basin A drainage pump installed in a pump well connected to the sand basin, having a main trough formed so that the sand collection pit side becomes deep in parallel with the water flow direction in the sand basin, and the sand collection pit inclined surface And a sand pump installed in the sand collection pit, a sand pump control means for controlling the sand pump, a water level detection means for detecting and outputting the water level of the water surface in the sand collection pit, A nozzle installed at the upper end of the main trough and the sand collecting pit slope, a stirring nozzle installed in the sand collecting pit, and a water flow direction in the sand basin on at least one side of the main trough on the bottom surface of the sand basin. Isometric surface in parallel direction For each of the divided areas, a nozzle header installed above the bottom surface in the vicinity of the side wall of the sand basin, with a number of nozzles attached at equal intervals, the main trough of water from the water supply pump, and And a switching valve group for controlling the switching operation of the switching valve group in a predetermined order. In the sand removal equipment,
(A) The sand pump control means starts an automatic operation mode based on a sand collection operation start command input, and when the water level of the sand basin reaches a predetermined level due to drainage by the drain pump, the switching valve control means Opens the trough nozzle switching valve and the stirring nozzle switching valve, and simultaneously starts the operation of the sand pump, stops the operation of the sand pump based on the low water level detection signal from the water level detection means, After closing the nozzle switching valve and the stirring nozzle switching valve of the main trough after the control means closes the nozzle header switching valve in the last order region, the automatic operation mode shall be released.
(B) After the sand removal operation start command is input, the switching valve control means opens the trough nozzle switching valve for a predetermined time and simultaneously opens the stirring nozzle switching valve for a predetermined time, and thereafter, the intermediate valve from the water level detection means Open the nozzle header switching valve in the earliest order area based on the water level detection signal, and thereafter input the intermediate water level detection signal from the water level detection means, until the nozzle header switching valve in the last order area, After closing the nozzle header switching valve that was open corresponding to the region in the order, opening the nozzle header switching valve in the next region, and closing the nozzle header switching valve in the last region, the water level The trough switching valve and the stirring nozzle switching valve were closed based on the input of the intermediate water level detection signal from the detection means,
A sand removal device for sand basins.   Each time the switching valve control means inputs an area order designating section for sequentially designating the order of areas where water should be jetted from the nozzle header, and an intermediate water level detection signal from the water level detecting means, A rank determination unit that determines whether or not the rank of the area specified by the designation unit is in the last order, and the trough nozzle switching valve is opened after the sand removal operation start command is input, and the rank determination unit is determined to be in the last order. A first switching valve control unit that closes the trough nozzle switching valve, and a nozzle header switching valve in a region designated by the region ranking designating unit for a predetermined period of time, so that an intermediate water level from the water level detection means The sand removal device for a sand basin according to claim 2, further comprising: a second switching valve control unit that closes the nozzle header switching valve by inputting a detection signal. A settling basin, in this case, the settling basin is a bottom surface inclined so that a part of the bottom of the settling basin is deep, a sand collecting pit formed in a part of the bottom, and a side wall on both sides of the settling basin A drainage pump installed in a pump well connected to the sand basin, having a main trough formed so that the sand collection pit side becomes deep in parallel with the water flow direction in the sand basin, and the sand collection pit inclined surface And a sand pump installed in the sand collection pit, a sand pump control means for controlling the sand pump, a water level detection means for detecting and outputting the water level of the water surface in the sand collection pit, At least one side of the main trough with the nozzle installed at the upper end of the main trough and the upper end of the sand collecting pit slope, the stirring nozzle installed in the sand collecting pit, and the bottom surface of the sand basin Direction of water flow in the sand basin For each of the regions divided in parallel directions, a nozzle header installed above the bottom surface in the vicinity of the side wall of the sand basin, attached with a number of nozzles, the main trough of water from the water supply pump, and And a switching valve group for controlling the switching operation of the switching valve group in a predetermined order. In the sand removal equipment,
(A) The sand pump control means starts an automatic operation mode based on a sand collection operation start command input, and when the water level of the sand basin reaches a predetermined level due to drainage by the drain pump, the switching valve control means Opens the trough switching valve and the agitation nozzle switching valve and simultaneously starts the operation of the sand pump, stops the operation of the sand pump based on the low water level detection signal from the water level detection means, After the control means closes the nozzle header switching valve in the last order region and then closes the trough switching valve and the stirring nozzle switching valve, the automatic operation mode shall be released.
(B) After the sand removal operation start command is input, the switching valve control means opens the trough nozzle switching valve for a predetermined time and simultaneously opens the stirring nozzle switching valve for a predetermined time, and then the nozzle header in the earliest order region. After the nozzle switching valve is opened for a predetermined time, the nozzle header switching valve is closed. Thereafter, each time the intermediate water level detection signal is input from the water level detection means, the nozzle header switching valve in the last order is sequentially A sand removal device characterized in that the nozzle header switching valve in the forward region is opened for a predetermined time and then the nozzle header switching valve is closed.   The switching valve control means each time the area order designation unit for sequentially designating the order of areas where water should be jetted from the nozzle header and the intermediate water level detection signal from the water level detection means are input at that time. A rank determination unit that determines whether or not the rank of the region specified by the unit is in the last order, and the rank determination unit after a sand removal operation start command is input or when an intermediate water level detection signal is input from the water level detection means After opening the trough nozzle switching valve for a predetermined time, and after opening the nozzle header switching valve for the region in which the rank is designated for a predetermined time, after opening the trough nozzle switching valve for a predetermined time, The sand removal apparatus according to claim 4, further comprising a second switching valve control unit that closes.

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