JP4006757B2 - Sand removal system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sand removal system in which sediment deposited in a sand basin such as a sewage treatment facility flows.
[0002]
[Prior art]
Conventionally, several proposals have been made regarding an apparatus for collecting earth and sand deposited in a sand basin of a sewage treatment facility in a sand collecting pit provided at the bottom of the sand basin. For example, in Patent Document 1, in a sand collection method for a sand basin that collects earth and sand accumulated in the sand basin in a sand collection pit with a plurality of water supply nozzles installed at the bottom of a sand basin equipped with a sand collection pit, At the same time as the water flows out, the water flowing out from the water supply nozzle is pumped out from the sand collection pit, so that the water level of the sedimentation basin is kept constant and the sediment deposited in the sand basin flows into the sand collection pit without being disturbed. A sand collecting method characterized in that it is made to occur is described.
[0003]
[Patent Document 1]
Japanese Patent No. 3315489 [0004]
[Problems to be solved by the invention]
However, the sand collecting device described in the invention of Patent Document 1 relates to sand collection and sand discharge in a sand basin, and the earth and sand settled in the sand basin is provided not at the pit provided in the pump water absorption tank but at the bottom of the sand basin. Collected in the sand collection pit. Although this method is effective as a method for cleaning a sand basin, since the liquid level is set to a relatively high position, a large capacity pump is required for sand collection. However, in recent pumping stations, it has become difficult to provide a sufficiently large sand basin due to the location and various conditions, and it is difficult to separate the sediment flowing in only the sedimentation basin from the viewpoint of sand collection efficiency. It is impossible. For this reason, sand and sludge with relatively small particles are likely to accumulate in the pump water absorption tank, and the bad odor generated from the accumulated sludge has become an environmental problem.
[0005]
SUMMARY OF THE INVENTION An object of the present invention is to provide a sand removal system capable of collecting earth and sand accumulated in a sand basin in a pit formed in a pump water absorption tank and efficiently discharging the collected earth and sand from the pit with a sand pump. It is said.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the sand removal system of the present invention connects a sand basin and a pump water tank with a central trough, and has a flow path inclined from the bottom surface of the central part of the sand basin toward the bottom surface of the pump water tank. A pit with a sand pump is formed on the bottom of the center of the pump water tank, and a gate between the sand basin and the pump water tank is suspended from the central trough, and the gate is closed to close the sand basin Sediment is deposited on the sedimentation basin, the gate is opened when the sedimentation basin is washed, and the sediment deposited in the sedimentation basin is flowed from the central trough to the pump suction tank, and then flows into the pit arranged at the bottom of the center of the pump suction tank. Discharging sediment from the pit with a sand pump, and connecting a sand collecting nozzle for collecting sand from a sand basin and a pump water tank to the discharge pipe of the sand pump; Sealed discharge piping That were provided with dust collector and auto strainer is characterized.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a sectional view of a sand removal system according to the present invention, and FIG. 2 is a plan view of the sand removal system according to the present invention. FIG. 3 is a flow sheet of the sand removal system according to the present invention.
[0008]
As shown in FIGS. 1 and 2, the sand removal system according to the present invention accumulates in the sand basin 1 so as to connect the bottom surface of the center portion of the sand basin 1 and the bottom surface of the center portion of the pump suction tank 2 in the longitudinal direction. A central trough 3 is provided as a flow path for allowing the earth and sand, etc., to flow into the pump water tank 2. A pit 8 having a sand pump 7 disposed therein is provided at the bottom of the central portion of the pump suction tank 2, and the treated water collected in the sand settling basin 1 is disposed below the pump suction tank 2. A main pump 9 to be sent to the next facility is arranged. The central trough 3 is provided with a gate 4 for preventing earth and sand accumulated in the sand basin 1 from flowing into the pump water tank 2. Further, a sand basin screen 5 is disposed at the rear end of the sand basin 1 and a pump water tank screen 6 is disposed at the upper part of the front stage of the pump water tank 2 in order to prevent inflow of residue.
[0009]
As shown in FIG. 3, the discharge line of the sand pump 7 is provided with a dust remover 11 that flows into the pump water tank 2 and removes residue and an auto strainer 10 that collects the earth and sand that flows into the pump water tank 2. . Also, between the sand pump 7 and the sand collecting nozzle 17, the sand collecting basin washing valve 20 for collecting and washing the earth and sand accumulated in the sand basin 1, and the sand collecting and sand collecting flowing into the pump suction tank 2, and A water absorption tank cleaning valve 21 for cleaning and a pump cooling valve 22 used for cooling the electric motor of the sand pump 7 are connected. The drain line of the auto strainer 10 is connected to a sand settling machine 12, and a sand set container 14 and a residue container 15 are provided on the discharge lines of the dust remover 11 and the sand set washing machine 12, respectively. In addition, a pump discharge water tank 18 is provided as a surplus water discharge destination of the sand pump 7.
[0010]
The sand removal system of the present invention thus formed collects the earth and sand accumulated on the bottom surface of the settling basin 1 in the pit 8 provided in the pump water tank 2 and efficiently removes it by performing the following cleaning operation. It is something that can be done.
[0011]
During normal operation, since the gate 4 suspended from the central trough 2 of the sand basin 1 is closed, the earth and sand that flows into the sand basin 1 together with the raw water and accumulates at the bottom of the sand basin 1 is pumped from the central trough 3 2 will not flow out. Further, the residue contained in the raw water is captured by the sand basin screen 5 and the pump water tank screen 6 when flowing from the sand basin 1 into the pump water tank 2. The raw water from which the earth and sand and sediment have been removed is sent from the main pump 9 disposed in the pump water absorption tank 2 to the next equipment. As shown in FIGS. 1 and 2, when the main pump 9 of the pump water tank 2 is provided with a circular bottom surface and a curved surface, the flow velocity is reduced when the main pump 9 is in operation. Even so, the residue will not settle.
[0012]
During the normal operation as described above, earth and sand gradually accumulate in the sand basin 1. Therefore, it is necessary to periodically clean the sand basin 1 in order to continue the stable treatment operation. Below, the washing | cleaning method of the sand basin 1 is demonstrated based on FIG. 1 thru | or FIG. At the beginning of the washing operation, the liquid level in the sand basin 1 is lowered by operating the main pump 9 from the normal level A to the washing level B. The reason why the liquid level in the sand basin 1 is lowered is to reduce the amount of water supplied by the sand pump 7 and increase the earth and sand concentration so that the sand pump 7 can be operated efficiently. During the cleaning operation, the supply of inflow water to the sand basin 1 is stopped. Next, the gate 4 provided in the central trough 3 is opened to form a passage through which the earth and sand accumulated in the sand basin 1 from the central trough 3 flows into the pump water absorption tank 2. The bottom surface of the sand basin 1 is inclined toward the central trough 3 so that the accumulated earth and sand can easily flow into the central trough 3. Further, the central trough 3 itself is also inclined from the sand basin 1 toward the pump water tank 2 so that the earth and sand flowing into the central trough 3 can be easily discharged to the pump water tank 2. The pit 8 into which earth and sand flows from the central trough 3 and the pump water absorption tank 2 is shaped so that earth and sand can easily flow, and is preferably coated with FRP. When the sedimentation basin washing valve 20 is opened while the sediment passage is formed in this manner and the operation of the sand pump 7 is started, the discharged water from the sand pump 7 is collected in the sand collection basin 1. The earth and sand accumulated in the settling basin 1 by the jet flow from the sand collecting nozzle 17 can be poured into the central trough 3. Further, when the water level is lowered to open the suction tank cleaning valve 21 and the operation of the sand pump 7 is started, the discharged water from the sand pump 7 reaches the sand collection nozzle 17 disposed in the pump suction tank 2 and is collected. The earth and sand accumulated in the pump water absorption tank 2 by the jet flow from the sand nozzle 17 can be poured into the central trough 3 and the pit 8. Since the autostrainer 10 and the dust remover 11 are provided between the sand pump 7 and the sand collecting nozzle 17, sediments and earth and sand contained in the washing water can be removed. Therefore, the sand collecting nozzle 17 is not clogged. Moreover, since the dust remover 11 has a sealed structure, the discharge pressure of the sand pump 7 can be secured up to the sand collecting nozzle 17, and the conventional system requires two units, a sand collecting pump and a cleaning pump. However, the sand removal system of the present invention can be achieved with one of the sand pumps 7. As described above, when the cleaning operation is continued, the sand collecting water is circulated, but the surplus water is sent to the pump discharge water tank 18 and the water level of the pump water absorption tank 2 gradually decreases. When the water level of the pump water tank 2 decreases, the electric motor of the pump becomes undercooled. At this time, if the pump cooling valve 22 is opened, cooling with washing water becomes possible. However, it is preferable to select a pump capable of operating in the air as the sand pump 7.
[0013]
【The invention's effect】
As described above, according to the invention described in claim 1 of the present application, it is possible to efficiently discharge sediment accumulated in the sedimentation basin and the pump water absorption tank from the pump water absorption tank to the sand removal treatment facility. The bad odor caused by sludge accumulated in the water tank is also suppressed. In addition, in the conventional method, in order to completely collect sediment and the like flowing into the sand basin, it is necessary to provide sand collecting facilities in both the sedimentation basin and the pump water absorption tank. In addition, sand collection in the sand basin and pump water tank can be performed in a batch in the pump water tank, reducing equipment costs. And according to invention of Claim 2 of this application, the sand collection of a sedimentation basin and a pump water absorption tank becomes easy by the jet flow from the sand collection nozzle connected with the discharge piping of the sand pump. Further, according to the invention described in claim 3 of the present application, since the closed dust remover and the auto strainer are disposed in the discharge pipe of the sand pump, the pressure of the sand pump is generated in the sand collecting nozzle, and normally Sand pumping and sand collection can be carried out with one sand pump for what requires two sand pumps and washing pumps.
[Brief description of the drawings]
FIG. 1 is a sectional view of a sand removal system according to the present invention.
FIG. 2 is a plan view of the sand removal system according to the present invention. FIG. 3 is a flow sheet of the sand removal system according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Sand basin 2 Pump water tank 3 Central trough 4 Gate 7 Sand pump 8 Pit 10 Auto strainer 11 Dust remover 17 Sand collecting nozzle

Claims (3)

A flow path in which a sand basin (1) and a pump water tank (2) are connected by a central trough (3) and inclined from the bottom of the center of the sand basin (1) toward the bottom of the center of the pump water tank (2). And a pit (8) provided with a sand pump (7) is provided at the bottom of the central portion of the pump water tank (2) and between the sand basin (1) and the pump water tank (2). The gate (4) is suspended from the central trough (3), the gate (4) is closed and sediment is deposited in the sand basin (1), and when the sand basin (1) is washed, the gate (4) is opened and the sand is sedimented. Sediment deposited in the pond (1) flows from the central trough (3) to the pump water tank (2) and flows into the pit (8) arranged at the bottom of the central part of the pump water tank (2). A sand removal system characterized in that earth and sand are discharged from the sand pump (7) from (8). The sand removal system according to claim 1, characterized in that a sand collecting nozzle (17) connected to a discharge pipe of the sand pump (7) is disposed in the settling basin (1) and the pump water tank (2). . The sand removal system according to claim 1 or 2, wherein a closed type dust remover (11) and an auto strainer (10) are arranged in a discharge pipe of the sand pump (7).

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