JP5812237B2 - Precipitation device for sediment in water tank - Google Patents

Description

  The present invention relates to an apparatus for removing precipitates in a sedimentation separation tank of a general water tank or a water treatment facility.

  In order to eliminate or collect sediment in the water tank, a scraper is attached to the chain or rope, scraped in a certain direction, or transported and accumulated in a certain direction by a screw conveyor consisting of a case and screw with the upper half open. After that, there is a method of suctioning with a centrifugal pump or a positive displacement pump, or removing it outside the water tank using a screw conveyor arranged vertically or inclined.

  JP 2001-347103 A   JP 2003-334404 A   JP-A-2005-342568   JP2008-12528

  In the method of discharging accumulated sediment sludge to the outside of the water tank using a centrifugal pump or positive displacement pump, it is very important that the accumulated sludge amount matches the pump discharge amount throughout the day even when the detection technology has developed. It is difficult to eliminate and recover the precipitate with a water content below the precipitation state. In the present situation, excess water is also inhaled and removed.

  Even in the case of using a screw conveyor that is vertical or inclined, in the case of a light and fine particle precipitate that is settled and separated using a flocculant, the moisture content in the precipitated state is not excluded. It is difficult and screw clogging is likely to occur.

  In order to reduce the amount of water in the sediment sludge, the handling and adjustment are just cumbersome if the pressurizing part and the filter mechanism are connected to the tip of the screw conveyor for horizontal transfer and have a throttling function. In particular, facilities that handle fine particles are not preferable because of many filter troubles.

  In addition, the cross-flow type sedimentation separation device, which is a type of gravity sedimentation separation method, has a layered separation plate in the separation water tank that is largely inclined in a plane parallel to the water flow direction and perpendicular to the water flow direction. In order to speed up the precipitation separation, a sediment reservoir is provided below the inclined separation plate, but the flow path of the liquid to be treated between the separation plates in which the inclined separation plates are closely packed In order to provide a flow channel for water to be treated with less resistance, a plurality of rough flow plates perpendicular to the water flow direction are arranged and partitioned to prevent this.

  However, in order to obtain a device that can be operated continuously, it is necessary to have a transfer facility such as scraping of sediment over the entire length of the separation plate, and the transfer facility has an unavoidably penetrating space in the water passage direction. In addition, since the resistance to running water is relatively low, not only is sufficient sedimentation separated, but it also becomes a channel that re-mixes the separated sludge that settles from the inclined separation plate (hereinafter referred to as “recessed channel”). From the experimental results, it has been found that there is a problem that the re-inflow near the end of the plate (hereinafter referred to as “kug water”) flows out into the treated water and deteriorates the separation performance.

  The screw conveyor for transfer installed almost horizontally at the bottom of the water tank such as a sedimentation water tank is capable of transporting water and sediment within the length range where the upper half of the case is open, but generates pressure. However, some pressure can be generated when the outer periphery of the screw is completely surrounded, and additional pressure can be obtained by gradually reducing the cross-sectional area of the screw or gradually decreasing the screw pitch. What can be done is easily understood from techniques such as a screw-type pump and a screw-type dewatering concentrator.

In the present invention, the sediment in the water tank is transported and accumulated on the tip side within the range where the upper half of the screw conveyor disposed almost horizontally at the bottom of the water tank is opened, and the fixed length range of the screw tip is reduced. The pressure case is configured to obtain a pressurizing pressure, and the end of the pressurization case is connected to the pressurization of a pump, screw conveyor, etc. Is opened outside the water tank at a position higher than the water level in the water tank.
The water level in the drainage pipe is equivalent to the water level in the tank in the non-pressurized state, and rises somewhat due to the operation of the screw conveyor.
In order to discharge the sediment accumulated in the sludge pipe to the outside of the water tank, it must be greater than or equal to “the sludge pipe head × the density of the liquid in the sludge pipe−the water head × the density of the liquid in the tank + the flow resistance of the sludge pipe”. Although a pressing force is required, the sediment can be discharged with a relatively small pressing force mainly composed of a liquid head difference.

The sediment sludge transferred by the screw conveyor and accumulated in the sludge pipe is crushed by the pressure of the screw and the weight of the sediment sludge.
Along with the nectar, the sediment sludge increases in viscosity, and the pressure increases more easily due to the effect of a decrease in leakage between the screw and the case gap, and the concentrated sludge is discharged from the upper end of the exhaust pipe.

  Furthermore, in order to obtain a sediment sludge with a small amount of water, a pressure impeller like an impeller of an axial flow pump is attached to the screw tip in the case to enhance the effect of pushing the sediment.

  Also in the cross-flow type sedimentation separation water tank, as described above, a screw conveyor equipped with a pressurizing unit is arranged at the bottom of the separation water tank, and a sludge pipe is connected, and a plurality of flow blocking plates below the sediment storage part. At the end, a hole close to the outer periphery of the screw is opened to allow the screw to pass therethrough, and the flow direction of the screw is opposite to the direction of water flow of the water to be treated in the separation water tank. Can be prevented from passing through water to prevent the separation accuracy of the apparatus from being lowered.

As described above, the apparatus of the present invention eliminates and collects concentrated precipitates only by using a horizontal transfer screw conveyor provided with a pressurizing unit, as compared with the case of using a vertical pump and screw conveyor equipment. The energy saving effect and economic effect on transportation, dehydration, drying, incineration, etc. in the latter stage are great.
In addition, in the cross-flow type sedimentation separation apparatus, the effect of preventing the passing water and improving the separation accuracy of the apparatus is great, and can greatly contribute to the downsizing of the apparatus in the water treatment field.

The sectional side view of the gravity type precipitation separation water tank of a 1st Example apparatus. AA sectional drawing of FIG. (A) is a BB cross-section detailed drawing of FIG. 1, (B) is a screw part detailed drawing in the AA cross section of FIG. The sectional side view of the transverse flow type gravity precipitation water tank of the 2nd example device. (C) is a cross-sectional view taken along the line CC in FIG. DD view of FIG. The partial detail sectional view of the Example which attached the pressure impeller to the screw front-end | tip. EE sectional detail drawing of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

In FIG. 1 to FIG. 3 which are gravity type precipitation separation water tanks of the first embodiment apparatus of the present invention, the water to be treated including suspended matters flowing from the inflow tank 2 of the separation water tank 1 is settled and separated in the separation area a It flows out to 樋 3.
The settled suspended matter settled in the sediment reservoir b, transferred in the counter-drive direction by the screw conveyor 11 with the upper half open, passed through the cylindrical pressure case 5 and discharged to the c portion of the sludge discharge pipe 6. Is done.
The upper part of the mud pipe 6 is provided with an upper mud pipe 7 that is slidable in the up and down direction and stopped by the packing 10, the upper end is opened, and the nectar with the sediment weight in the mud pipe and the water surface The sediment sludge concentrated by the dehydrating action in the upper part d is discharged and slides out from the chute 8.

  The screw part enclosed in the pressure case 5 at the tip of the screw conveyor 11 gradually reduces the screw pitch as necessary, or gradually decreases the cross-sectional area of the screw 11 and the pressure case 5 to increase the pressurizing force. Can be planned.

  The upper end open position of the upper sludge pipe 7 is set as high as possible within the range where discharge is possible in accordance with the properties of the sediment, and the amount of discharged sludge moisture is reduced.

A lateral flow type gravity sedimentation tank apparatus according to the second embodiment will be described with reference to FIGS.
In the case of the present embodiment, the vertical adjustment of the sludge pipe 6 is unnecessary, and the water to be treated introduced from the raw water introduction pipe 17 passes through the inclined separation plate 21 provided in the separation water tank 1. In the meantime, it is settled and separated, the treated water flows out to the outflow basin 3, and the separated sludge settles in the sediment reservoir b.
The sediment reservoir b is partitioned by a plurality of baffle plates 23 orthogonal to the direction of water flow to prevent the treated water from passing through, and the bottom is large enough to prevent the screw conveyor 11 from rotating. The hole is opened and the screw 11 is penetrated.

  The baffle plate 23 of the apparatus of this embodiment is intended to completely separate the sediment reservoir b and maintain the separation accuracy. However, the gap between the screw 11 and the baffle plate 23 and the blade of the screw 11 itself. The squeezed water is generated from the gaps between the pitches. By moving the direction of the screw conveyor in the direction opposite to the direction of the water to be treated, the flow of sediment is generated along with the transport of the precipitate. Therefore, it is possible to prevent the passing water and maintain the separation accuracy of the apparatus.

The embodiment shown in FIGS. 7 and 8 shows an embodiment in which an impeller-like pressure impeller 31 of an axial flow pump having three blades at the tip of a screw 11 is mounted and fixed with a nut 32.
The pressurizing impeller 31 is expected to act to push the sediment sludge into the sludge pipe 6 with a spatula rather than the hydraulic pump action in the case of the apparatus of this embodiment having a low rotation speed. By making them separately, there are advantages that the number of blades and the blade angle can be freely selected, and that the material can be manufactured with a material having good wear resistance.

  Further, when the apparatus of the present invention is stopped, there is a problem that the sediment sludge that is not excluded remains in the sludge pipe 6. However, before the apparatus is stopped, the rotational speed of the screw 11 is temporarily increased. Therefore, the hydraulic pressure of the pressure impeller 31 is increased, and the impeller of the axial flow pump has a characteristic that the pressure increases as the amount of water decreases (250 to 300% at the cutoff point). Waste sludge can be eliminated.

  The apparatus for removing sediment in the water tank of the present invention can discharge the sediment sludge that is more concentrated than the natural sediment state to the outside of the water tank, and additionally discharges the sediment that has been conventionally required to the outside of the tank. Pumps and vertical or inclined screw conveyors are not required, including sedimentation tanks for water treatment equipment, any tank where sediment is generated, and places where sludge is likely to accumulate in rivers and lakes. Can be used.

DESCRIPTION OF SYMBOLS 1 Separation water tank 2 Inflow tank 3 Outflow tank 4 Screw conveyor case 5 Pressurizing case 6 Drain pipe 7 Upper mud pipe 8 Mud chute 9 Treated water connection port 10 Packing 11 Screw conveyor screw 12 Bearing case 13 Bearing 14 Seal 15 Screw drive motor 16 Chain 17 Raw water input pipe 21 Inclined separation plate 22 Separation plate retainer 23 Block plate 31 Pressure impeller 32 Clamping nut a of pressure impeller 31 Separation area b Precipitate storage part c Drainage Mud pipe start end d Waste mud pipe end e Inflow area f Outflow area

Claims (3)

In the horizontal flow type sedimentation separation tank, the upper half of the sediment storage part below the inclined separation plate penetrates the baffle plates to the deepest part of a plurality of baffle plates that are divided perpendicular to the water flow direction. A screw conveyor consisting of a case and a screw with an open end is arranged so as to transfer sediment in a direction reverse to the direction of water flow of the water to be treated , and a fixed length at the end of the screw delivery side is added to the cylinder. The pressure part is inserted into the pressure case to constitute a pressurizing part, and a sludge pipe extending upward is connected to the end of the pressure case, and the upper end is opened at a position higher than the separation water tank water level. Exclusion device. 2. The precipitate eliminating device according to claim 1, wherein an impeller-like pressure impeller of an axial flow pump is attached to a screw tip of a screw conveyor. The apparatus for removing precipitates according to any one of claims 1 and 2, wherein the rotational speed of the screw is temporarily increased before the apparatus is stopped or in order to prevent clogging of the drainage pipe.

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