JPH07102281B2 - Sand basin structure - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sand basin structure in a water treatment facility such as a sewage treatment facility or a water purification facility.

2. Description of the Related Art Conventionally, in a sewage treatment facility or a water purification facility, a sand basin is provided as a facility for removing suspended matter such as sediment from the inflowing sewage and the raw water taken. Then, the sand basin is provided with a device that scrapes the sediment deposited at the bottom into the sand pit.As the scraping device, a device that scrapes the sand by mechanical operation such as a flight conveyor, a screw conveyor, and a mean, In some cases, the settling sand was attracted by a jet stream of pressure water jetted from a cylindrical pressure water jet nozzle located at the bottom of the pond.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in a sand basin using the above-mentioned conventional scraping device that performs mechanical operation, when the amount of sediment deposited in the sand basin increases due to an increase in suspended matter during rainfall or the like, , The movable parts were sometimes buried in the sand and could not be driven. In addition, there is a problem that the mechanical operation causes severe wear and requires maintenance. Moreover, in a sand basin using a device that draws sand by a jet water flow, it takes 10 to 30 minutes to inject the pressure water, and there is a problem that the amount of accumulated water used as pressure water is large and the power consumption is large. It was In addition, there is a problem that the jet water flow jetted from the cylindrical pressure water jet nozzle does not spread in the channel width direction of the sand basin, the amount of sand left behind is large, and the scraping efficiency is low. Further, since a sand basin pit is provided at the downstream end of the sand basin and the pressure water is jetted to the downstream side, there is a problem that suspended sediment due to agitation by jet water flows into the pump well beyond the sand pit.

The present invention solves the above problems, and an object of the present invention is to provide a sand basin structure capable of transferring sand to a sand pit with a small amount of accumulated water without scratching the sand.

Means for Solving the Problems In order to solve the above problems, the present invention provides a raw water that flows from an upstream side to a downstream side, and in a sand basin in which a sand pit is formed at the bottom, near the bottom of the sand basin. Is provided with a plurality of pressure water injection nozzles for injecting pressure water toward the sand pit, and the pressure water injection nozzles are formed by forming nozzle openings in a thin plate.

In addition, in a sand basin where raw water flows from the upstream side to the downstream side, a sand pit is provided at the bottom on the upstream side, and pressure water is jetted toward the upstream side near the bottom on the downstream side following the sand pit. A plurality of pressure water jet nozzles are arranged. The pressure water jet nozzles are arranged in rows at appropriate intervals in the width direction of the sand basin, and are also provided in rows at appropriate intervals in the raw water flow direction. The inclined surface having an upward slope in the pressure water jetting direction is formed between the rows of the pressure water jet nozzles at the bottom of the sand basin.

By the above-mentioned configuration, the pressure water jet nozzle is formed by forming a nozzle opening portion in a thin plate, and since the nozzle flow path is short,
The pressure water ejected from the nozzle hole spreads in the channel width direction of the sand basin, the jet water flow acts on the sand in a wide area, and the entrained flow is generated around the jet water flow in the same direction as the jet water flow. A synergistic effect is exerted, the efficiency of scraping sand by the jet water flow is improved, and there is no leftover sand scraping, and it is possible to reduce the cumulative amount of pressure water, the water pressure, and the injection time.

Further, the settling deposits on the bottom of the settling basin on the downstream side of the settling pit, in descending order of specific gravity according to the settling velocity based on the specific gravity. Then, first, pressure water is jetted from the pressure water jet nozzles arranged in the row located on the most downstream side to transfer the sediment toward the upstream side, and the pressure water jet nozzles sequentially arranged in the row on the upstream side. The sand is transferred to the sand pit by injecting pressured water from.

At this time, since the specific gravity of the sediment that accumulates further downstream from the sediment pit is smaller, the energy required for transporting the sediment can be saved. Also, because the pressure water jet nozzles are arranged at appropriate intervals in the width direction of the sand basin,
Sediment is drawn over the entire width of the channel. Furthermore, since the jet water flow is jetted from the downstream side to the upstream side, sedimentation suspended by the jet water flow does not flow out to the downstream side, and adverse effects on downstream processes and equipment are prevented.

At the bottom of the settling basin, the settling sand moves along the inclined surface and is transferred over the pressure water injection nozzle on the upstream side by the inertial force, so the pressure water injection nozzle does not become an obstacle on the transfer route of the settling sand. In addition, sedimentation of the pressure water jet nozzle is suppressed.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, a sand basin 1 forms a flow path through which raw water 2 flows from an upstream side to a downstream side, and a sand pit 3 is formed at the bottom of the sand basin 1 at the upstream side and a sand pit 3 is formed. A plurality of pressure water injection nozzles 5 for injecting the pressure water 4 toward the upstream side are arranged near the bottom portion on the downstream side. This pressure water jet nozzle 5 has a thin plate 5a and a nozzle opening 5b.
The nozzle opening 5b is formed in a vertical slit shape. The pressure water jet nozzles 5 are arranged in rows at appropriate intervals in the channel width direction of the sand basin 1, and are arranged in rows at appropriate intervals in the flow direction of the raw water 2. Further, each pressure water jet nozzle 5 is connected to a pressure water main pipe 6 via a nozzle mounting pipe 7 for each row, and each pressure water main pipe 6 is connected to a pressure water supply pipe 9 via an electric on-off valve 8. It is in communication. Furthermore, the pressure water supply pipe 9
A pressure feed pump 10 is provided midway. An inclined surface 11 is formed between the rows of the pressure water injection nozzles 5 at the bottom of the sand basin 1, and the inclined surface 11 has an upward slope in the injection direction of the pressure water 4. A sand lifting device 12 is provided in the sand pit 3.

The operation of the above configuration will be described below. The raw water 2 flowing into the sand basin 1 flows from the upstream side to the downstream side, and the sand set 13 flowing into the sand basin 1 together with the raw water 2 is from the one having a larger specific gravity in accordance with the settling velocity based on the specific gravity, and the sand pits are successively arranged. 3 and the settling pit 3 is deposited and deposited on the bottom of the settling basin 1 downstream of the settling pit 3.

Then, the sand settling 13 is transferred at regular intervals or when an appropriate amount of sand settling 13 is accumulated on the bottom of the sand settling basin 1. This procedure will be described. First, the electric open / close valve 8 installed in the pressure water main pipe 6 located on the most downstream side is opened, and the pressure pump 10
The pressure water 4 supplied by the above is supplied to each pressure water jet nozzle 5 through the pressure water supply pipe 9, the pressure water main pipe 6, and the nozzle mounting pipe 7. And the nozzle opening 5b of the pressure water jet nozzle 5
The pressure water 4 is jetted from the jetted water, and the settling sand 13 is transferred to the upstream side by the jet flow of the jetted pressure water 4. At this time, since the pressure water jet nozzle 5 is formed by forming the nozzle opening portion 5b in the thin plate 5a and the nozzle flow path is short and opens in the vertical slit shape, the pressure water 4 jetting from the nozzle opening portion 5b is formed. Spread in the width direction of the sand basin 1, the jet water flow acts on the sand in a wide area, and further, a companion flow is generated around the jet water flow in the same direction as the jet water flow, thereby producing a synergistic effect. For this reason, the settling by the jet stream
In addition to improving the scraping efficiency of 13, the settling of the settled sand 13 is eliminated, and it is possible to reduce the accumulated water amount of the pressure water 4, the water pressure, and the injection time. Furthermore, at the bottom of the sand basin 1, the sand 13 moves along the inclined surface 11 and is transferred by the inertial force over the pressure water jet nozzle 5 on the upstream side. Not only is it not an obstacle on the transfer path, but it is possible to suppress the accumulation of settling sand 13 on the pressure water jet nozzle 5.

After that, the electrically operated on-off valve 8 interposed in the upstream pressure water main pipe 6 is sequentially opened, and the pressure water 4 is injected from the pressure water injection nozzles 5 provided in each pressure water main pipe 6 to remove the settling sand 13. Transfer to sand pit 3. At this time, since the settling 13 deposited on the downstream side farther from the settling pit 3 has a smaller specific gravity, the settling
The energy required to transfer 13 can be saved. Moreover, since the pressure water jet nozzles 5 are arranged at appropriate intervals in the width direction of the sand basin 1, the sand is raked over the entire width of the flow path. Furthermore, since the jet water flow is jetted from the downstream side to the upstream side, the sediment 13 suspended by the stirring by the jet water flow does not flow out to the downstream side,
The adverse effects on downstream processes and equipment are prevented.

EFFECTS OF THE INVENTION As described above, according to the present invention, by arranging the pressure water jet nozzles formed of thin plates at appropriate intervals in the width direction of the flow path, the pressure water jetted from the nozzle openings is settled. The jet water flow can be applied to a wide range of sedimentation by spreading it in the width direction of the pond, improving the efficiency of scraping the sand by the jet water flow, and scraping the sediment over the entire width of the flow path. It is possible to eliminate leftover scraps, reduce the cumulative amount of pressure water, the water pressure, and the injection time. In addition, by setting a sand pit on the upstream side of the sand basin and arranging a pressure water injection nozzle on the downstream side of the sand pit, the specific gravity becomes smaller for the sediment that accumulates farther downstream from the sand pit to transfer the sand. Labor saving of required energy can be achieved. Further, by jetting the jet water stream from the downstream side to the upstream side, the sedimentation suspended by the stirring by the jet water stream is prevented from flowing out to the downstream side, and the adverse effect on the downstream process and equipment is prevented. be able to.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is an enlarged sectional view of a pressure water jet nozzle in the same embodiment. 1 ... sand basin, 2 ... raw water, 3 ... sand pit, 4 ...
Pressure water, 5 ... Pressure water jet nozzle, 5a ... Thin plate, 5b ...
Nozzle opening, 11 …… Inclined surface, 13 …… Sand settling.

Claims (2)

[Claims] 1. In a sand basin in which raw water is passed from an upstream side to a downstream side and a sand pit is formed at the bottom, a plurality of pressure water is jetted toward the sand pit near the bottom of the sand basin. The pressure water jet nozzle is provided, and the pressure water jet nozzle is formed by forming a nozzle hole portion in a thin plate. 2. In a sand basin through which raw water flows from upstream to downstream, a sand pit is provided at the bottom of the upstream side, and pressure is applied toward the upstream near the bottom of the downstream side following the sand pit. A plurality of pressure water jet nozzles for jetting water are arranged, and the pressure water jet nozzles form a row at an appropriate interval in the channel width direction of the sand basin and a plurality of cases at an appropriate interval in the raw water flow direction. A sand basin structure, characterized in that an inclined surface which is provided on the slope and forms an upward slope in the direction of injection of pressure water is formed between each row of pressure water injection nozzles at the bottom of the sand basin.