JP2000279715A - Solid-liquid separation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent the clogging of a nozzle and filter cloth and to stabilize the separation and dehydration treatment capability of a solid component and liquid component by equipping the apparatus with a filter cloth washing means having the self-washing type nozzle and a washing fluid supplying means which is capable of intermittently changing the supply pressure of the washing fluid to the self-washing type nozzle. SOLUTION: The filter cloth 2 is circumferentially rotated by a drive roll 3 and a pressure reduction vessel 6 is internally decompressed by a pressure reduction blower 14. The original liquid supplied to a original liquid supply vessel 5 is forcibly sucked to the pressure reduction suction vessel 6 side via the filter cloth 2 to suck the liquid component in the original liquid by the pressure reduction suction vessel 6. The solid component is captured by the filter cloth. The liquid component is once stored in a sealing vessel 10. On the other hand, the solid component is transferred together with the filter cloth 2 to a pressure dehydrating means consisting of a metallic drum 7, a pressure roll 8, etc., and is transferred to the metallic drum 7 side, following which the solid component is scraped by a scraper 9 and is dropped to a cake receiving vessel 17. The surfaces of the filter cloth 2 are thereafter washed by the washing means 3 having the self-washing type nozzle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-liquid separation device which is suitably used for solid-liquid separation of an undiluted solution containing a suspended substance or the like, and more particularly to a device capable of reducing maintenance and clogging a filter cloth. The present invention relates to a solid-liquid separation device capable of preventing a solid-liquid separation.

[0002]

2. Description of the Related Art Conventionally, a rotating filter cloth has been used to continuously and solid-liquid separate a stock solution containing planktonic species such as blue-green algae and fine silt-like suspended substances such as sludge and earth and sand. A dehydrator and a filter are used, and there is a problem that the solid-liquid separation efficiency of the filter cloth decreases with the operation time due to accumulation of suspended substances.

In order to suppress a decrease in the solid-liquid separation efficiency due to such a filter cloth and to enable continuous operation for a long time, a washing nozzle is installed in the middle of the orbital movement path of the filter cloth, and washing water is supplied from the washing nozzle. It is known to operate while spraying to regenerate the filter cloth.

[0004] In this case, for the purpose of efficiently regenerating the filter cloth, it is preferable to use water substantially free of suspended substances as washing water. Or a filter that can be used as a filter, or another filter for removing suspended substances in washing water is newly required.

[0005] On the other hand, in order to conserve water, there is a case where, as washing water, miscellaneous water or washing wastewater containing some suspended substances is recycled and used. However, in this case,
Frequently, nozzles are clogged by suspended matter contained in the water. As a result, the cleaning recovery of the filter cloth is reduced, and the processing performance and stability are lacking.Moreover, labor, time and cost are required for maintenance of the nozzle, and furthermore, the processing is not stopped during the maintenance. There is a problem that must not be.

[0006]

SUMMARY OF THE INVENTION The present invention reduces the burden of maintenance due to clogging of a washing nozzle, prevents a decrease in the recovery of the filter cloth from being washed, and enables a solid-liquid liquid that can be operated for a long time with the same filter cloth. It is an object to provide a separation device.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a filter cloth running means, a stock solution supply means provided on the front side of the filter cloth, and a stock solution supply means on the back side of the filter cloth. Pressure-reducing suction means provided in opposition to the means, pressure dehydrating means provided downstream of the pressure-reducing suction means with respect to the direction of travel of the filter cloth, filter cloth cleaning means having a self-cleaning nozzle, and self-cleaning nozzle A solid-liquid separator having cleaning fluid supply means capable of intermittently changing the supply pressure of the cleaning fluid to the solid-liquid separator.

Here, the self-cleaning type nozzle has a plurality of peach-sprayable spray tips and springs provided in the main body, and the plurality of spray tips are adapted to the pressure of the cleaning fluid acting on the spray tips. It is preferable that the plurality of spray tips be configured to move up and down by a balance with the restoring force of the spring and to crack when located below. More preferably, when the cleaning fluid pressure is smaller than the spring restoring force, the cleaning fluid is united when the cleaning fluid is smaller than the spring restoring force. In addition, providing a reflux means for returning at least a part of the used cleaning fluid to the self-cleaning nozzle, providing the self-cleaning nozzle in a pipe provided with a cleaning fluid discharge valve, and further cleaning It is preferable to provide an auto strainer upstream of the self-cleaning nozzle with respect to the flow direction of the fluid.

[0009] A fresh water producing method using any of the above solid-liquid separation devices is also preferable.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A solid-liquid separator of the present invention separates a solid-liquid contained in a supplied stock solution by a traveling filter cloth 2 as shown in, for example, a filter cloth traveling dehydrator 1 in FIG. The apparatus includes a solid-liquid separation unit, a filter cloth cleaning unit 13 provided with a self-cleaning nozzle, and a pump 12 having a timer 18 capable of intermittently changing the pressure of a cleaning fluid supplied to the self-cleaning nozzle. Things.

In this filter cloth traveling dehydrator 1, the filter cloth 2
Is provided so as to continuously rotate endlessly between a plurality of guide rolls 4 including a drive roll 3, and a stock solution supply tank 5 for supplying a stock solution to the surface of the filter cloth 2 is provided.
In addition, a vacuum suction tank 6 having a vacuum blower 14 is provided on the back side of the filter cloth 2 and at a position opposite to the stock solution supply tank 5, and further, a vacuum suction tank with respect to the traveling direction of the filter cloth 2. Downstream from 6, a pressurized dewatering means for sandwiching and dewatering the filter cloth 2 is provided. The pressure dewatering means receives the metal drum 7 and the pressure roll 8 for pressing the filter cloth 2, the scraper 9 for scraping off the solid component dewatered and transferred to the metal drum 7, and receives the scraped solid component. A cake receiving tank 17 is provided. Thus, the solid-liquid separation means is configured.

A filter cloth cleaning means 13 having a self-cleaning type nozzle for automatically discharging foreign matter trapped in the filter cloth downstream of the solid-liquid separation means with respect to the direction of travel of the filter cloth, and receives the cleaning drainage. A drain tank 11 is provided. In addition, for convenience of explanation, an embodiment in which the self-cleaning type nozzle is provided in the surface washing means of the filter cloth will be described, but the self-cleaning type nozzle may be provided in any of the surface cleaning means and the backwash means of the filter cloth. , Or both.

As shown in FIG. 2, the self-cleaning type nozzle 32 includes a pump 12 having a timer 18 and a cleaning fluid discharge valve 34 for discharging cleaning water remaining when cleaning is stopped. The pipe 33 is provided. The cleaning fluid discharge valve 34 can prevent suspended substances contained in the cleaning water from sticking in the pipe.

As shown in FIGS. 3 and 4, the self-cleaning type nozzle 32 includes a plurality of spray tips 51 on a main body 54.
A spring 55 and a built-in spray tip 51
Due to the balance between the pressure of the cleaning fluid acting on the spray tip and the restoring force of the spring 55, the spray tip 51 moves up and down and cracks when it is located below.

As shown in FIG. 5, the spray tip 51 is designed to crack at a base 59 as a starting point.
As shown in FIG. 4, a spring 55 is placed from above, and a ring-shaped elastic member 56 is fitted to the base 59, and is provided in the main body 54. In this state, the spray tip 51 is in a state of peach cracks as shown in FIG.

However, when a cleaning fluid having a certain pressure or more is sent to the self-cleaning nozzle 32, a cleaning fluid pressure greater than the restoring force of the spring 55 is applied to the base 59 of the spray tip 51. As shown, the spray tip is pushed upward and the tip of the spray tip merges along the inner surface of the reduced diameter body 54 to form a cleaning fluid outlet 58.

When the cleaning fluid is again reduced to a certain pressure or less, the restoring force of the spring 55 exceeds the pressure applied to the base 59 of the spray tip 51, so that the spray tip is pushed down again as shown in FIG. And peach cracks.

Such a self-cleaning type nozzle is self-cleaned by repeatedly supplying a cleaning fluid at a pressure not lower than a certain value and supplying the cleaning fluid at a pressure not higher than a certain value by a timer or the like. . When the fluid pressure is reduced to a certain value or less, the spray tip breaks pink and foreign matter is discharged from the spray tip to the outside of the nozzle.
Also, when the supply of the cleaning fluid is stopped, the residual fluid,
In addition, the foreign matter is discharged to the outside of the nozzle by the cleaning fluid supplied until the ejection port at the time of restart is formed.

The filter cloth traveling dehydrator 1 further stores at least a part of the washing wastewater and the filtrate obtained by reducing the pressure of the reduced-pressure suction tank 6 while reducing the pressure of the reduced-pressure blower 1.
4 is provided with a sealing tank 10 for maintaining the reduced pressure, and the washing wastewater and the filtrate stored in the sealing tank 10 are supplied with a timer-1.
It is returned to the washing means 13 by a pump 12 with 8 controls. Further, an auto strainer 15 for removing suspended substances contained in the fluid to be refluxed, and a solenoid valve 23 for extracting the suspended substances removed by the auto strainer 15 are also provided. Note that this extraction solenoid valve 23
Is provided with a timer 19 for automatic control.

Here, the filtrate and fresh water (purified water from which suspended substances have been separately removed) are allowed to flow into the sealing tank 10 without flowing the washing wastewater, and the stored fluid is used to remove the filter cloth. Although washing may be performed, in the configuration of the present invention, the washing wastewater already used for washing can be refluxed, and the washing of the filter cloth can be performed mainly using the washing wastewater and the filtrate. Such a washing drainage and a filter cloth washing mainly comprising a filtrate cannot be stably operated because clogging of the filter cloth and reduction of the processing amount are caused in the conventional apparatus configuration. However, the self-cleaning nozzle 32 and the intermittent By using the cleaning fluid supply means that can change the cleaning fluid supply pressure to
It is possible to prevent clogging of the filter cloth and a reduction in the treatment amount, and as a result, it becomes possible to recycle a large amount of cleaning wastewater. Further, by adding and using the auto strainer 15 on the upstream side of the self-cleaning type nozzle with respect to the flow direction of the cleaning fluid, the filter cloth can be cleaned only with the filtrate and the cleaning drainage without using new water. Therefore, it is not necessary to supply fresh water as filter cloth washing water, which is required in the conventional solid-liquid separation device, and it is possible to largely save resources.

In the above-described filter cloth traveling dehydrator 1, the filter cloth 2 is circulated in the direction of the arrow by the drive roll 3 and the inside of the reduced pressure suction tank 6 is reduced in pressure by the reduced pressure blower 14. I have. Therefore, in the solid-liquid separation, the undiluted solution supplied to the undiluted solution supply tank 5 is forcibly sucked into the reduced-pressure suction tank 6 through the filter cloth 2, and the liquid component in the undiluted solution is sucked into the reduced-pressure suction tank 6. This is performed by capturing the solid components with a filter cloth. Then, the liquid component obtained by the suction under reduced pressure is temporarily stored in the seal tank 10.

On the other hand, the separated solid component moves together with the filter cloth 2 to a pressurizing and dehydrating means comprising a metal drum 7 and a pressurizing roll 8 and is pressed by the metal drum 7 and the pressurizing roll 8. Is further dehydrated and transferred to the metal drum 7 side. The solid component transferred to the metal drum 7 is scraped off by the scraper 9, falls into a cake shape, and falls into the cake receiving tank 17.

The filter cloth 2 from which the cake has been removed is then washed on its front surface by a washing means 13 having a self-cleaning type nozzle, and, if necessary, by washing the filter cloth 2 from its back face by a washing means 20. I do. At this time, washing of the filter cloth 2
It is preferable to perform the operation intermittently using the automatic timer 18 or the like. By performing intermittent cleaning automatically by a timer, clogging of the self-cleaning nozzle 32 can be prevented,
It is possible to prevent the filter cloth 2 from being clogged and a filter performance from being lowered.
The cleaning time of the filter cloth depends on the concentration of the undiluted solution and the water used for cleaning, but the operation must be stopped and restarted before the self-cleaning nozzle is completely clogged (before the change in cleaning water pressure alone can no longer cope with it). It is preferable to repeatedly and frequently discharge foreign matter from the nozzle.

At least a part of the washing wastewater is temporarily stored in the seal tank 10 by adjusting the opening degrees of the valves 21 and 22, and the remaining washing wastewater is sent to the drain tank 11. The water in the seal tank 10 is used as washing water together with a liquid component obtained by suction under reduced pressure by a pump 12 as washing water 13.
Refluxed to At this time, the suspended material contained in the supplied washing water is removed by the auto strainer 15. When the amount of water in the seal tank exceeds a certain amount, the water overflows and flows out to the drain tank 11, and when it becomes insufficient, fresh water is supplied through the ball-tub valve 16.

In the present invention, the raw water may be subjected to a coagulation treatment in advance. Further, a filter cloth cleaning means having a self-cleaning type nozzle used in the present invention and a cleaning fluid supply means capable of intermittently changing the supply pressure of the cleaning fluid to the self-cleaning type nozzle are provided by a rotary drum type filter or the like. It is preferable to use it for other types of solid-liquid separation devices.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An apparatus shown in FIG.
The solid-liquid separation of sludge (no chemical injection) was performed. The experimental conditions were as follows. <Operating conditions> Pressure of pump 12: 3 kg / cm ² Setting of pump 12: operation 5 minutes, stop 5 seconds (setting of timer 18: operation 5 minutes, stop 5 seconds) Mesh of auto strainer 15: 40 mesh Extraction solenoid valve 23 Setting: opening 10 seconds, closing 60 minutes Washing fluid: total washing drainage and filtrate (Valve 21: Fully closed, Valve 22: Fully open, do not use fresh water) As a result of the above experiment, clogging of the self-cleaning type nozzle Stable operation for 720 hours (30 days) was performed without any success. Further, the sludge treatment amount was 20 kg-DS / Hr (standard amount), and the SS recovery rate was 70%.

[0027]

The solid-liquid separator of the present invention comprises a filter cloth cleaning means having a self-cleaning nozzle and a cleaning fluid supply means capable of intermittently changing the supply pressure of the cleaning fluid to the self-cleaning nozzle. Since it is provided, clogging of the nozzle and the filter cloth can be prevented, and the ability to separate and dehydrate solid components and liquid components can be stabilized. Further, maintenance due to nozzle clogging can be reduced. Further, the amount of new water as washing water for the filter cloth can be reduced, and the operating cost can be reduced.

Here, when the self-cleaning type nozzle is provided on the pipe provided with the cleaning fluid discharge valve, the cleaning water stays in the pipe when the operation is stopped, and the suspended substance contained in the cleaning water adheres. Can be prevented. Further, in the case where a recirculation means for recirculating at least a part of the used cleaning fluid to the self-cleaning nozzle is provided, and an auto-strainer is provided on the upstream side of the self-cleaning nozzle with respect to the flow direction of the cleaning fluid, resources Can be greatly saved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a solid-liquid separation device showing one embodiment of the present invention.

FIG. 2 is a schematic diagram showing the cleaning means of FIG.

FIG. 3 is a schematic longitudinal sectional view showing a state in which a spray tip of the self-cleaning type nozzle of FIG.

FIG. 4 is a schematic longitudinal sectional view showing a state in which the spray tips of the self-cleaning type nozzle of FIG. 3 are combined (during filter cloth cleaning).

FIG. 5 is a schematic perspective view showing a spray tip of the self-cleaning nozzle of FIG. 2;

[Explanation of symbols]

 1: filter cloth traveling dehydrator 2: filter cloth 3: drive roll 4: guide roll 5: stock solution supply tank 6: reduced pressure suction tank 7: metal drum 8: pressure roll 9: scraper 10: seal tank 11: drain tank 12: Pump 13: Cleaning means 14: Decompression blower 15: Auto strainer 16: Ball tap valve 17: Cake receiving tank 18: Timer 19: Timer 20: Cleaning means 21: Valve 22: Valve 23: Extraction solenoid valve 32: Self-cleaning nozzle 33: Pipe 34: Cleaning fluid extraction valve 51: Spray tip 54: Main body 55: Spring 56: Ring-shaped elastic member 58: Injection port 59: Base

Claims (7)

[Claims] 1. A filter cloth traveling means, a stock solution supply means provided on the front side of the filter cloth, a reduced pressure suction means provided on the back side of the filter cloth and opposed to the stock solution supply means, Pressure dewatering means provided downstream of the vacuum suction means in the direction, filter cloth cleaning means having a self-cleaning nozzle, and cleaning capable of intermittently changing the supply pressure of the cleaning fluid to the self-cleaning nozzle A solid-liquid separation device comprising: a fluid supply unit. 2. The self-cleaning type nozzle has a plurality of peach-sprayable spray tips and a spring provided in a main body of the nozzle, and the plurality of spray tips includes a pressure of a cleaning fluid acting on the spray tip and a spring. 2. The solid-liquid separation device according to claim 1, wherein the solid-liquid separation device is configured to move up and down according to a balance with a restoring force and to be cracked when located below. 3. A plurality of spray tips unite when the pressure of the cleaning fluid acting on the spray tip is greater than the restoring force of the spring, and when the pressure of the cleaning fluid is smaller than the restoring force of the spring, the plurality of spray tips break. The solid-liquid separation device according to claim 2, wherein 4. A recirculation means for recirculating at least a part of the used cleaning fluid to the self-cleaning nozzle.
4. The solid-liquid separation device according to any one of claims 1 to 3. 5. The solid-liquid separation device according to claim 1, wherein the self-cleaning type nozzle is provided in a pipe provided with a cleaning fluid discharge valve. 6. The solid-liquid separation device according to claim 1, wherein an auto-strainer is provided upstream of the self-cleaning nozzle with respect to the flow direction of the cleaning fluid. 7. A fresh water producing method using the solid-liquid separation device according to any one of claims 1 to 6.