JP2002282607A - Sand collecting device of sedimentation basin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that a deeper downstream end of a central trough and a deeper sand-collecting pit are required in the case where a sedimentation basin is long although a down slope is provided on the central trough toward the sand-collecting pit in a conventional sand-collecting device. SOLUTION: The sedimentation basin is provided with the sand-collecting pit at a bottom thereof. The sand-collecting device of the sedimentation basin has a first trench 21 formed on the bottom of the pond toward the sand- collecting pit 3 and provided with a screw conveyor 22 therein, a plurality of second trenches 24 formed downwardly inclinedly toward the first trench 21, and a water-jetting nozzle 25 disposed at the bottom of the pond toward the first trench 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sand collecting device for a sand basin for temporarily collecting sediment settled in a sand basin in a sewage treatment facility in a sand collecting pit in order to discharge the sediment from the sand basin.

[0002]

2. Description of the Related Art Heretofore, in collecting sand in a sand basin, a sand collecting device for transferring sediment deposited and deposited in the sand basin by water injection to a sand collecting pit has been used. For example, JP-A-7
Japanese Patent Publication No. -100306 discloses a sand collecting device as shown in FIGS. 4 is a plan view of the sand collecting device, FIG. 5 is a view taken along the line CC of FIG. 4, and FIG. 6 is a view taken along the line DD of FIG. In the figure, reference numeral 30 denotes a sand basin. A sand collecting pit 31 is provided at a substantially central portion in the longitudinal direction, and a pond bottom 32 is formed with a downward slope from both sides toward the sand collecting pit 31. A central trough 33 is also provided at a substantially central portion in the width direction of the pond bottom 32 with a downward gradient from both sides toward the sand collecting pit 31. From both sides of the central trough 33, a central trough 33 is provided in the width direction of the pond bottom 32. A plurality of branch troughs 34 are provided in a downward slope toward. A water injection nozzle 36 is provided at an upper end of a bottom 35 at an intermediate portion between the central trough 33 and the branch troughs 34, 34. A nozzle 37 for water injection is provided at the upper end of the central trough 33. When sand collection is performed by this apparatus, the water in the sand basin 30 is removed to expose the bottom 32, and the sediment deposited on the bottom 35 is washed away by the nozzle 36, and the sand is poured into the branch trough 34. The soil and water flow down the branch trough 34 having a downward slope and flow into the central trough 33. The earth and sand and water flowing into the central trough 33 flow down the downwardly inclined central trough 33 by the water jetted from the nozzle 37 and flow into the sand collecting pit 31. The sediment and water accumulated in the sand collecting pit 31 are discharged out of the sand basin 30 by a sand pump 38 installed in the sand collecting pit 31, and are appropriately treated.

[0003]

However, the above sand collecting apparatus has the following problems. Sand collecting pit 3
A downward slope of about 1/100 is provided in the central trough 33 toward 1, which is necessary for smoothly flowing down the earth and sand. However, when the sedimentation basin 30 is long, the downstream end of the central trough 33 and the sand collecting pit 31 need to be deeper. In order to secure this required depth, the existing concrete skeleton may be dug down in some cases. There is a problem that unnecessary construction must be performed. An object of the present invention is to solve the above-mentioned problems, and to provide a sand collecting device for a sand basin in which a central trough can be made substantially horizontal and unnecessary construction is not required.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a sand basin having a sand collecting pit at the bottom of a pond, wherein the sand pit is formed at the bottom of the pond toward the sand collecting pit, and a screw conveyor is provided therein. A sand collecting device for a sand basin, comprising: a groove; and a water jet nozzle disposed at a bottom of the pond toward the first groove. In the present invention, when a plurality of second grooves are formed in a downward slope toward the first groove, the movement of the sand toward the first groove becomes smooth. Further, when a flat bottom is formed between each of the second grooves, and the water ejection nozzle is arranged so as to face this bottom, the movement of the sand toward the first groove is further smoothed. . Further, the sand can be moved at a lower nozzle ejection pressure by attaching a metal plate to the first groove and / or the second groove. If treated water taken in the process after the sand basin is used as the jet water used for the water jet nozzle, clogging and wear of the nozzle can be suppressed because the amount of sand contained is small.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the sand collecting device for a sand basin according to the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing a sand collecting device for a sand basin according to the present invention, FIG. 2 is a view as viewed from an arrow A in FIG. 1, and FIG. 3 is a view as viewed from an arrow B in FIG. 1 is a sand basin,
Sewage flows in from the direction of arrow I. A sand bottom 2 is formed at the bottom of the sand basin 1, a sand collecting pit 3 is provided at a substantially central position in the sewer flow direction of the pond bottom 2, and a sand pump 4 is installed therein. Pond bottom 2 and water collection pit 3
The mortar is formed by casting mortar on top of the mortar. A central trough 21 is provided substantially horizontally at a substantially central portion in the width direction of the pond 2, and the central trough 21 communicates with the sand collecting pit 3 across the pond 2. A screw conveyor 22 is rotatably installed in the central trough 21. Bottom portions 23 are formed on both sides of the central trough 21 so as to have a downward slope toward the central trough 21, and a plurality of branch troughs 24 are formed on the bottom portion 23 at substantially equal intervals toward the central trough 21. It is provided so as to have a downward slope and communicates with the central trough 21. A nozzle 25 for water injection is arranged near an upper end of a substantially central portion in the width direction of each of the bottom portions 23 partitioned by the branch troughs 24, and this nozzle 25 is connected to a water supply pipe 26.

A pump well 5 is provided on the sewage outflow side of the sand basin 1, and a transfer pump 6 and a supply pump 7 are installed in the pump well 5. The transfer pump 6 transfers the treated water temporarily stored in the pump well 5 to the first settling basin, which is the next step, and the supply pump 7 supplies the treated water in the pump well 5 to the aforementioned nozzle for jetting water. 25 for use in sand collection.

Next, the operation of the above configuration will be described. When performing sand collection work, first stop the inflow of sewage into the sand basin 1 and then drain the sewage in the sand basin.
The inside of the sand basin 1 is emptied so that the bottom 23 is exposed. When the bottom 23 is exposed, water is sprayed from the nozzle 25 to wash out the sediment deposited on the bottom 23, and the earth and water flow down to the branch trough 24. The earth and sand and water flowing down to the branch trough 24 flow down to the central trough 21 by the downward gradient of the branch trough 24. The soil and water flowing down to the central trough 21 are forcibly transferred to the sand collecting pit 2 by a screw conveyor 22 installed therein. If water is ejected from the nozzles 27 at the same time, the transfer of earth and sand by the screw conveyor 22 can be performed more smoothly.
The sediment and water collected in the sand collecting pit 2 are discharged out of the sand basin 1 by the sand pump 4 and are appropriately treated. Since the screw conveyor 22 forcibly transfers earth and sand, the earth and sand can be transferred without any trouble even if the central trough 21 where the screw conveyor 22 is installed is formed horizontally.

The pressure of the water jetted from the nozzle is
Because it is only about to wash away the sediment deposited on 3
Normal tap water pressure, that is, about 0.1 MPa is sufficient. In the groove of the central trough 21 and the branch trough 24, a metal plate,
For example, when a stainless steel plate is applied inside, the flow of earth and sand becomes smoother than only the ground of concrete, which is more preferable. In this embodiment, the water spouted from the water spouting nozzle uses the treated water in the pump well, but is not limited to this.For example, overflow water from the first sedimentation basin or the final sedimentation basin is used. Can also be used. In this way, water can be effectively used.

[0009]

According to the present invention having the above-described structure, the first groove can be made substantially horizontal, and a sand collecting device for a sand basin that does not require unnecessary construction can be provided.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of a sand collecting device for a sand basin of the present invention.

FIG. 2 is a view as viewed in the direction of arrows AA in FIG. 1;

FIG. 3 is a view taken in the direction of arrows BB in FIG. 1;

FIG. 4 is a plan view showing a conventional sand collecting device for a sand basin.

FIG. 5 is a view taken in the direction of the arrows CC in FIG. 4;

FIG. 6 is a view as seen from the direction of the arrow DD in FIG. 4;

[Explanation of symbols]

1 settling basin, 2 pond bottom, 3 sand collecting pit, 4 sand pump, 5 pump well, 7 feed pump, 21 central trough (first groove), 22 screw conveyor, 23 bottom, 24 branch trough (second Groove), 25 nozzles

Claims (5)

[Claims] 1. A settling basin having a sand collecting pit at the bottom of a pond, wherein the first groove is formed on the bottom of the pond toward the sand collecting pit, and a first groove provided with a screw conveyor therein; And a water jet nozzle disposed at the bottom of the pond toward the ditch. 2. The sand collecting device for a sand basin according to claim 1, further comprising a plurality of second grooves formed to be inclined downward toward the first grooves. 3. The settling basin according to claim 2, further comprising a flat bottom formed between each of the second grooves, wherein the water jet nozzle is disposed so as to face the bottom. Sand equipment. 4. The sand collecting device for a sand basin according to claim 1, wherein a metal plate is internally bonded to the first groove and / or the second groove. 5. The treated water taken in a process after the sand basin is used for the water jet nozzle.
5. The sand collecting device for a sand basin according to any one of claims 1 to 4.