JPH03275103A - Method and device for discharging settled sand - Google Patents

Abstract

PURPOSE:To simplify the equipment by collecting and discharging the settled sand in a settling basin with only one pump. CONSTITUTION:A sand settling pit 2 is provided at the terminal of a settling basin 1 in its flow direction, and plural sand collecting nozzles 8 for injecting water in the flow direction are furnished at the bottom of the basin 1. A sand pump 3 is provided above the pit 2 and made freely liftable, and a first pipeline 5 is connected to the delivery port 3a of the pump 3. A settled sand cleaning separator 6 is connected to the outlet of the pipeline 5, a first valve 7 is provided to the pipeline 5, and a branch pipe 5a is attached to the pipeline 5 on the pump 3 side of the valve 7. The branch pipe 5a and the nozzles 8 are connected by a second pipeline 9, and a second valve 10 is provided to the pipeline 9. Consequently, the settled sand in the basin is collected and discharged with only one pump, and the equipment is simplified.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method and device for discharging sediment accumulated in a settling basin of a sewage treatment plant or a pumping station, and particularly relates to a method and an apparatus for discharging sediment accumulated in a settling basin of a sewage treatment plant or a pumping station, and in particular, Concerning the method and apparatus used.

[Prior Art] Conventionally, the method of mechanically scraping up sediment using a well-known packet conveyor has often been used to discharge sediment from a settling pond.

However, in recent years, from the viewpoint of low construction costs and ease of maintenance, methods have begun to use water injection to accumulate sediment and sand pumps to discharge the sediment.

Specifically, Japanese Unexamined Patent Publication No. 63-62508 discloses that a water injection nozzle is installed at the bottom of a pond facing downstream, and sediment is accumulated by injecting pressurized water.

Furthermore, Japanese Utility Model Publication No. 60-31308 discloses that a screw conveyor is arranged at the bottom of the pond, the sediment accumulated on the bottom of the pond is collected in a settling bit, and this is discharged together with water by a sand pump. Disclosed.

[Problems to be solved by the invention] However, in all of the techniques disclosed in the above-mentioned publications, the accumulation and discharge of sand are performed using separate equipment, which naturally increases the complexity of the equipment and the construction cost. It was an invitation.

An object of the present invention is to improve the above-mentioned drawbacks and provide a simple and inexpensive method and device for discharging sediment.

[Means for Solving the Problems] The present invention provides a method and device for discharging sediment from a settling basin, in which a settling pit is provided at the end of the settling basin in the flow direction, and water is poured into the bottom of the settling basin in the flow direction. A plurality of sand-filling nozzles are arranged so as to eject sand, a sand pump is arranged above the sand settling pit I~ so as to be able to rise and fall freely, and the first pipe line is connected to the discharge port of the sand-lifting pump. A sand settling cleaning separator is connected to the outlet end of the pipe, a first valve is provided in the first pipe, and the first pipe branches from the first valve to the sand pump side. A pipe is provided, the branch pipe and the sand nozzle are connected by a second pipe line, and a second valve is disposed in the first and second pipe line. It is characterized in that a concentration meter and a flow meter are interposed in the first pipe line between the first valve and the sand washing separator, and further, a concentration meter and a flow meter are interposed between the first valve and the sand washing separator. It is characterized in that a water tank is connected to the first pipe between the two, and furthermore, the sand pump is lowered from a part of the standby position and stopped at a predetermined position in the underwater part. , Close the first valve and operate the sand pump to eject water from the sand nozzle to transfer the sand to the sand bit, and after a predetermined time, lower the sand pump and close the first valve. When the sand pump has finished suctioning the sand and has landed on the bottom of the sand bit, the sand pump is stopped and the second valve is closed. This is a characteristic feature.

[Example] Embodiments of the present invention will be described based on the drawings.

FIG. 1 is a skeleton diagram showing an outline of an embodiment of the present invention, and FIG. 2 shows flowcharts 1 to 1.

In the figure, 1 is a sand settling basin, which has a slightly downward slope in the downstream direction, and a sand settling pit 2 is provided at its downstream end. A sand pump 3 is suspended above the sand pits I-2 via a lifting device @4. A first pipe line 5 is connected to the discharge port 3a of the sand pump 3, and a sand cleaning separator 6 is disposed at the outlet end of the first pipe line 5. A branch pipe 5a is provided in the middle of the first pipe line 5. In one pipe line, branch pipe 5a
A first valve 7 is disposed closer to the sand settling washing separator 6 side.

The first valve 7 is a solenoid valve or an electric valve. A plurality of sand nozzles 8 are arranged facing the bottom of the sand settling basin 1 and facing toward the sand settling pit 2. The sand nozzle 8 and the branch pipe 5a are connected by a second conduit 9, and a second valve 10 is disposed between the branch pipe 5a and the sand nozzle 8.

The second valve 10 is also a solenoid valve or an electric valve.

Next, we will explain how to operate the above-mentioned device.

Normally, when sand pumping work is not performed, the sand pump 3
Pull it above the water surface. When starting the sand lifting operation, the sand lifting pump 3 is first lowered by the lifting device 4.

When the sand pump 3 reaches a position below the water surface that does not suck up the accumulated sand, the position detector detects that the sand pump 3
stop the descent.

The position detector may be a well-known limit switch.

The above-mentioned lowering stop position of the sand pump 3 is checked in advance and set in the position detector.

Next, operate the sand pump 3, close the first valve 7,
Next, the second valve 10 is opened. Then, water from the sand pump 3 is ejected from the sand nozzle 8, and the sand accumulated on the sand settling basin 1 is transferred to the sand settling pit 2 and accumulated therein.

Stopping the above-mentioned sand pump 3 below the water surface at a position where it will not suck up the accumulated sediment, to prevent unnecessary sand from flowing into the sand collection nozzle 8 and the second pipe 9 and clogging them. This is to prevent premature wear and tear.

After operating the sand pump 3 for a predetermined time, the second valve 10
is "closed" and the first valve 7 is "opened".

Then, the water sucked by the sand pump 3 is discharged into the sand washing separator 6 through the first pipe line 5. The sand discharged into the sand washing separator 6 is stirred and washed with water there to be separated into organic components and sand, and the sand is pumped out by normal means.

The sand pump 3 must be lowered appropriately in order to suck and discharge the sediment, but this is done by an operator who lowers the sand pump 3 by a fixed distance at fixed intervals while watching a timer.

After suctioning and discharging the sand from the sand pit 2, the sand pump 3
settles on the bottom of sand pits 1 and 2. By setting this landing position in the position detector, the descent will automatically stop.

Thereafter, the sand pump 3 is raised, and when it reaches the standby position, it is stopped and left on standby until the next operation.

Next, a second embodiment will be described.

In this embodiment, a concentration meter 1 and a flow rate meter 2 are connected in the first pipe line 5 between the first valve 7 and the sediment cleaning separator 6.

In this embodiment, the sand pump 3 described above is automatically raised and lowered, and in particular, the lowering of the sand pump 3 is correlated with the amount detected by the concentration meter 1.

This will be explained in detail below.

First, when the measured value F of the flowmeter 12 (here, the discharge amount of the sand pump 3) is equal to the specified value, no blockage has occurred in the sand pump 3 or the first pipe line 5. It is judged to be "normal".

Next is the upper limit defined as the measured value of concentration i+11.

The lower limit values are compared, and the following judgments and actions are performed based on the results.

(1) If the measured value of the concentration meter 11 is smaller than the lower limit, the sand pump 3 continues to descend.

(2) If the measured value of the concentration meter 11 is greater than the lower limit value and smaller than the upper limit value, the sand pump 3 stops descending, and the sand is sucked and discharged at that position, settling the sand within the suction range of the sand pump 3. When it disappears, the measured value becomes smaller than the lower limit value, so the sand pump 3 descends.

(3) If the measured value of the concentration meter 11 becomes larger than the upper limit, the sand pump 3 is raised once and the operation returns to (1).

When the sand pump 3 reaches the bottom of the sand settling pit 2,
The lowering is stopped by the position sensor, and when it rises and reaches the standby position, it stops and waits until the next operation.

Next, the third embodiment will be explained in detail.

In this embodiment, a water tank 13 is connected to the above two embodiments. Specifically, the water tank 1-3 is in the first pipe line 5.
It is connected midway between the sand washing separator 6 and the flow meter 12.

When the measured value F of the flowmeter 12 is smaller than the specified value, it is determined that the sand pump 3 is blocked, and the sand pump 3 is rotated in the reverse direction to suck makeup water in the water tank 13 from its discharge port 3a side. , discharge to the original suction side.

By doing so, the blockage of the sand pump 3 can be easily released.

[Effects of invention According to the invention, accumulation of sediment in a settling basin.

Discharge can be performed using a single pump, simplifying equipment.

[Brief explanation of drawings]

Fig. 2 shows a schematic skeleton diagram of an embodiment of the present invention, and Fig. 2 shows a flowchart. 1; Sand settling basin, 2; Sand settling pit, 3; Sand lifting pump, 4; Lifting device, 5; First pipe line, 6; Sand settling washing separator, 7; First valve, 8; Sand nozzle, 9 ; second pipe line, 10; second valve, 11; concentration meter, 12; flow rate side, 13;
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Claims (1)

[Claims] 1) A sand settling pit is provided at the end of the sand settling basin in the flow direction, and a plurality of sand nozzles are arranged so as to spout water in the flow direction at the bottom of the sand settling basin, and above the sand settling pit. A sand pump is arranged to be able to move up and down, a first pipe line is connected to the discharge port of the sand pump, a sand cleaning separator is connected to the outlet end of the pipe line, and a sand washing separator is connected to the outlet end of the pipe line. A first valve is provided, a branch pipe is provided in the first pipe line closer to the sand pump than the first valve, and the branch pipe and the sand nozzle are connected by a second pipe line, A sediment discharge device characterized in that a second valve is disposed in a second pipe. 2) In the first pipe line between the first valve and the sand washing separator,
The sediment discharge device according to claim 1, characterized in that a concentration meter and a flow meter are interposed. 3) In the first pipe line between the first valve and the sand washing separator,
The sand settling and discharging device according to claim 1 or 2, characterized in that a water tank is connected. 4) A method for discharging sand using the settling and discharging device according to claim 1, 2, or 3, in which the sand pump is lowered from a standby position above the water to a predetermined position in the underwater part. The sand pump stops at the first position, closes the first valve, operates the sand pump, blows out water from the sand nozzle, transfers the sand to the sand pit, and after a predetermined period of time, lowers the sand pump and operates the sand pump. Open the valve, close the second valve, detect that the sand pump has finished suctioning the sand and landed on the bottom of the sand pit, stop the sand pump, and raise it. Characteristic sand discharge method.