JPH08318107A - Filter - Google Patents

Abstract

PURPOSE: To surely discharge an oil component floating on a water surface while preventing a filter medium from being discharged during backward washing. CONSTITUTION: In a filter in which raw water is passed through a filter bed 12 in a downflow to be filtered and washing water is passed through the filter bed in an upflow to backwash the filter bed, in a space above the filter bed in a filter column 10, a trough 19 from which raw water overflow and also into which waste washing water overflows to regulate a water surface W in the column at an upper surface 19', a separation inclined body 22 placed below the trough 19 and having, on the upper surface, a downward inclined part 23 whose lower end forms a vertical flow passage 24, and the 1st and the 2nd baffles 26, 27 vertically installed above the downward inclined part 23 of the separation inclined body 22 with their lower ends being separated form the inclined part 23 are formed. The 1st baffle 26 is placed near the flow passage, and the 2nd baffle 27 is separated from the 1st baffle, vertically toward the trough. The upper ends of the 1st baffle 26 and the 2nd baffle 27 are positioned under the water surface regulated by the trough 19 in the column, and at the same level as the water surface W regulated by the upper surface of the trough in the column, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention allows raw water to flow through a filter bed packed in a filter tower in a downward flow to perform filtration treatment, and air and washing water to flow through the filter bed in an upward flow. The present invention relates to a filter device for developing and cleaning a filter layer.

[0002]

2. Description of the Related Art In a filtering device for performing such a downflow filtration and an upflow washing (backwashing), a part of the filter material constituting the filter layer is mixed with the washing drainage during the backwashing using air together. In order to prevent the water from being discharged to the outside of the tower, the inclined guide plate is set up in the water in the space above the filter bed in the filtration tower, and it is erected above the slope of the inclined guide plate, and the upper end is above the water surface. A solid-liquid separation device consisting of a vertical baffle plate protruding from the inclined guide plate is provided, and a part of the filter medium rolled up on the inclined guide plate by backwash is transmitted to the upper surface of the inclined guide plate by a downward flow, It is known to drop the film from the lower end onto the filter layer and return it.

[0003]

The above-mentioned solid-liquid separation device can prevent a part of the filter medium from being mixed with the cleaning drainage and discharged during backwashing, but the air can move laterally on the water surface. The oil that floats above the water surface is not discharged because it is blocked by the upper end of the vertical baffle plate that projects above the water surface in order to release it from the air vent at the top of the tower. However, the oil gradually contaminates the filter medium, causing deterioration of the treated water.

[0004]

The present invention was developed in order to solve the above-mentioned problems, and the raw water is passed through the filter bed filled in the filtration tower in a downward flow to carry out the filtration treatment. ,
In a filter device in which air and wash water are passed through the filter layer in an upward flow, and the filter layer is developed and washed, raw water overflows into the space above the filter layer in the tower, and wash drainage overflows. A trough that enters and controls the water surface in the tower with an upper surface, and a separating slant that is located below the trough and that has a downward slope on the upper surface, and the lower end of the downward slope forms a vertical flow path. And two baffles, a first baffle and a second baffle, which are erected with their lower ends separated from each other, above the downwardly inclined portion of the separation inclined body. The first baffle is near the flow path, and the second baffle is the first baffle. Stand upright from the first baffle toward the trough, and the upper end of the first baffle is below the water level in the tower controlled by the trough, and the upper end of the second baffle is at the same level as the water level in the tower controlled by the upper surface of the trough. It is characterized by being located in.

[0005]

EXAMPLES In each of the illustrated examples, 10 is a filtration tower,
On the water-passing support plate 11 in the lower part of the tower, a gravel 13 is provided as the lowermost layer, a sand filter medium layer 14 is formed thereon, and an anthracite filter medium layer 15 is further laminated thereon to form a filter layer 12. In the lowermost layer of the gravel 13, a supply / discharge pipe 16 that doubles as an outflow pipe for treated water and an inlet pipe for wash water for backwashing is laid up, and an air supply pipe 17 for compressed air for backwashing is laid down. is there.

In the space 18 above the filter layer 12 in the filter tower, there is provided a trough 19 to which a pipe 20 is connected, which serves to both supply raw water and discharge cleaning wastewater. The raw water supplied from the pipe 20 into the trough during the filtration process overflows from the upper surface of the trough, and the washing wastewater that has flowed upward in the filter layer during the backwash process overflows into the trough from the upper surface to the inside of the tower. It is discharged outside. In both the filtering step and the backwashing step, the water surface W in the filtration tower is regulated by the trough 19 and is at the same level as the upper surface 19 'thereof.

Reference numeral 22 denotes a separating slant body provided below the water surface below the trough 19, and the upper surface thereof is a downward slant portion 23, and the lower end of the downward slant portion is a flow path which is opened in the vertical direction. The raw water that forms 24 and overflows from the trough 19 and flows downward flows along the downwardly inclined portion, flows down the flow path 24, reaches the upper surface of the filter layer 12, and flows downward in the filter layer to be filtered.
In addition, the washing drainage flowing upward in the filter layer ascends in the flow path 24, reaches the water surface W, and overflows into the trough. When backwashing is performed by using air together, in order to prevent air from accumulating under the lower surface of the separation inclined body, the lower surface 25 of the separation inclined body is an upward slope toward the flow path 24, and the air lowers the lower surface 25. Flow path 24
It is preferable to move to and float.

A first baffle 26 and a second baffle 27, which is separated from the first baffle 26 toward the trough, are erected in the water on the downwardly inclined portion 23 of the separation inclined body near the flow path 24. The lower ends of the baffles 26 and 27 are slightly apart from the upper surface of the downward slope 23. First baffle 26
Is above the water surface, and the upper end of the second baffle 27 is located at the same level as the water surface W.

In the embodiment shown in FIGS. 1 and 2, the trough 19 and the separating slant 22 are provided in the same diameter direction of the filter, and the width of the trough is narrow, whereas the separating slant is wide and the filtering tower is wide. Is about 3/4 of the diameter of the filtration tower, and the flow path 24 is between the left and right sides of the separation slant 22 and the inner circumference of the filtration tower, and is about 1/3 of the diameter of the filtration tower.
Two are formed with a width of eight. And the first baffle 2
Two 6 are erected in parallel with the trough above the left and right sides of the separation slant. Further, two second baffles 27 are provided upright in parallel with the first baffle, apart from the first baffle toward the trough.

The pipe 20 penetrates through the bottom of the filtration tower for supporting the trough 19 and the separating slant 22 and stands along the center of the tower, and the upper end thereof penetrates through the central bottom of the diametrical trough of the tower. It is open. Central part 1 of trough where pipe 20 opens
9 ″ has a bulge, which allows the raw water that has risen in the pipe 20 to enter the inside of the trough 19 during the filtration process.
The treated water overflows into the tower from both sides of the entire length of the trough 19, flows downward through the filter layer 12 through the flow path 24, is filtered, and the treated water flows out from the treated water drain pipe 28 connected to the supply / discharge pipe 16. or,
During the backwashing process, the cleaning wastewater overflows into the trough 19 and is discharged from the discharge pipe 21 connected to the trough.

In the embodiment shown in FIGS. 3 and 4, the trough 19 and the separating slant 22 are provided circumferentially along the inner circumference of the filtration tower. The downward sloping portion 23 of the upper surface of the separating sloping body is sloping downward toward the center of the tower, and the inner circumference of the lower end of the downward sloping portion forms a circular channel 24 that is open in the vertical direction in the central portion of the tower. Therefore, the raw water which is supplied to the trough 19 and overflows flows down through the flow path 24 and flows downward in the filter layer 12 to be filtered, and the treated water is drained from the treated water drain pipe 2 connected to the water supply / drain pipe 16.
Outflow from 8.

The first baffle 26 has an annular shape and is erected downwardly of the separating slanting body above the inner circumference of the lower end of the slanting portion or near the flow path. The second baffle 27 has an annular shape having a diameter larger than that of the first baffle, and the trough 1 extends from the first baffle.
They are erected concentrically and separated from each other.

In any of the embodiments shown in FIGS. 1, 2, 3 and 4, the backwashing step can be arbitrarily set, but normally, the step of loosening the filter layer with only air, or the combination of air and washing water is used. To remove the SS adhering to the filter medium, the flow rate is increased to exfoliate the SS adhering to the filter medium only with washing water, and the exfoliated SS is discharged, and the filter layers have a plurality of different specific gravities. When the filter material layer is used, it comprises a step of classifying the filter material at the boundary surface of the filter material layer.

In order to carry out the step (1), compressed air from the compressor is supplied to the air supply pipe 17 at a rate of 20 to 50 m / hour for 3 to 10 minutes, and the filter layer is loosened by the bubbles flowing upward in the filter layer to form a filter medium. The attached SS is peeled off from the filter medium, and the peeled SS is pushed up to the upper part of the filter layer. The bubbles that have flowed upward in the filter bed travel along the lower surface 25 of the separation gradient body and move toward the flow path 24, and rise to the water surface directly above the flow path 24, and from the air vent 10 'opened at the top of the tower. Released to the outside.

After the step (3) is completed, the backwash pump P connected to the washing water supply pipe 29 is operated while the air is continuously supplied, and the washing water is supplied at a flow rate of 20 to 50 m / hour for 3 to 10 minutes.
Supplied for a minute, air and wash water are allowed to flow upward into the filter layer, the SS attached to the filter medium is peeled off, and the peeled SS together with the wash drainage is caused to rise in the channel 24 to overflow into the trough 19, Discharge from tube 20.

In this case, the washing drainage that has risen in the flow path 24 flows toward the trough 19 while passing over the first baffle 26 whose upper end is below the water surface, but the second baffle 27 whose upper end is at the same level as the water surface. The flow is blocked and the flow is moderated, the flow a toward the trough 19 over the upper end of the first baffle becomes small, and most of the flow b descends between the first and second baffles, and the separation slant is directed downward. Along the sloping portion 23, there is a flow c that dives under the first baffle toward the flow path 24 and a flow d that goes up the downward sloping portion and dives under the second baffle toward the trough 19. The SS flows on the flow d, overflows into the trough, and is discharged from the discharge pipe 21. Further, the filter medium rolled up from the flow path 24 onto the separation slant falls on the downward slanted portion by gravity while descending between the first and second baffles, and is separated from the flow d and rides on the flow c. , Rolls over the downward slope, reaches the flow path 24, and then falls onto the upper surface of the filter layer to be collected. The air used together with the wash water rises in the flow path 24, floats on the water surface W, and is discharged to the outside from the air vent 10 '.

In the step (1), washing water is supplied at a flow rate of 60 to 100 m / hour for 3 to 10 minutes to flow upward in the filter layer to remove the SS attached to the filter medium, and the removed SS to the pipe 20. At the same time, the mixed filter medium is classified at the boundary surface of a plurality of filter medium layers having different specific gravities of the multilayer filtration device. Since the flow rate of the washing water is faster than that of the step, the amount of the filter medium wound up on the separation slant increases, but in this case also, the flow a toward the trough 19 beyond the upper end of the first baffle is small,
Most of the flow b descends between the first and second baffles and flows under the first baffle toward the flow path 24, and flows under the second baffle up to the trough. d
Therefore, the filter medium wound up on the separating slant falls down on the downward slant part by gravity when descending the first and second baffles and is separated from the flow d, and rides on the flow c and descends on the downward slant. It rolls down to reach the channel 24, falls from the channel onto the upper surface of the filter layer, and is collected.

During the steps (1) and (2), the oil content floating on the water surface W between the first and second baffles is removed by the second baffle 27.
A slight flow of water is passed over the upper end of the trough 19 toward the trough 19, overflows into the trough, and is discharged to the pipe 20. Therefore, oil does not accumulate, and there is no room for contamination of the filter medium.

In this way, the second end whose upper end is at the same level as the water surface W
The baffle lifts the flow path 24 to mitigate the relatively strong flow towards the trough and prevents the filter media from flowing into the trough, and causes a slight flow above the upper end to float above the water surface. The role of sending the oil that has been made to the trough, and S
It has the role of making S or the like go under the lower end and ascending along the downwardly inclined portion of the separation inclined body to go to the trough. or,
The first baffle, whose upper and lower ends are below the surface of water, makes the flow moderated by the second baffle downward in cooperation with the second baffle and tilts the filter medium contained in the flow downward of the separating slant. It has the role of causing the oil content to float while falling on the section, and the role of diving under the lower end of the section, descending along the downward slope, causing a flow toward the flow path 24, and collecting the filter medium. This effectively discharges SS and oil, and collects the filter medium.

In the illustrated embodiment, a plurality of filter medium layers having different specific gravities are used as the filter layer 12, and a multilayer filter layer having a smaller specific gravity is laminated on top, but the filter layer is not limited to this. It may be composed of a kind of filter medium. A pipe 20 for supplying raw water to the trough 19 penetrates the bottom of the filtration tower, stands along the center of the tower, and has an upper end penetrating the bottom of the trough. It may be one that passes through the first baffle and the second baffle and opens on the side surface of the central portion of the trough. Further, although the pipe 20 is used to both supply the raw water and discharge the cleaning waste water, the discharge pipe 21 communicating with the trough 19 is provided, and the pipe 20 for supplying the raw water and the discharge pipe 2 for discharging the cleaning waste water are provided.
1 may be provided independently.

[0021]

As is apparent from the above, according to the present invention, the raw water supply pipe and the cleaning wastewater discharge pipe are connected to the space above the filter bed in the filtration tower to overflow the raw water. In addition, the washing drainage overflows and the trough that controls the water surface in the tower by the upper surface and the trough located below the trough and on the upper surface have a downward slope, and the lower end of the downward slope is the vertical flow. A separation slant forming a passage and two baffles, a first and a second baffle which are erected with their lower ends separated, are provided above the downward slant portion of this separation slant, and the first baffle is near the flow path. In addition, the second baffle is erected separately from the first baffle toward the trough,
Moreover, the upper end of the first baffle is located below the water surface in the tower regulated by the trough, and the upper end of the second baffle is located at the same level as the water surface in the tower regulated by the upper surface of the trough.
The filter material constituting the filter layer can be effectively washed by performing backwashing at a frequency of about twice, so that the mud balls are not formed and the filter material is discharged together with the cleaning drainage during the backwashing. It can be prevented, yet the oil can be discharged, and there is no room for contamination of the filter medium due to the accumulation of oil. From the results of the experiment, it has been found that the discharge amount of the filter medium can be suppressed to 5% or less of the filling amount, assuming that the filter medium has been operated for 300 days a year.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a first embodiment of a filtration device of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a vertical cross-sectional view of another embodiment of the filtration device of the present invention.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

[Explanation of symbols]

 10 Filter Tower 11 Water-passing Support Plate 12 Filter Layer 16 Supply / Discharge Pipe 17 Compressed Air Supply Pipe 18 Upper Space of Filter Layer in Filter Tower 19 Trough 19 'Top of Trough 20 Pipe 21 Discharge Pipe 22 Separation Gradient 23 Separation Gradient Lower sloped part of the upper surface of the body 24 Flow path in the vertical direction 25 Lower surface of the separation slanted body 26 First baffle 27 Second baffle 28 Drain pipe of treated water 29 Supply pipe of wash water W Water level in filtration tower

Claims (1)

[Claims] 1. Raw water is passed in a downward flow into a filter layer packed in a filtration tower for filtration treatment, and air and washing water are passed in an upward flow to the filter layer to develop the filter layer. In the filtration device for cleaning by washing, the raw water overflows into the space above the filter layer in the tower, and the trough that controls the water surface inside the tower by the overflow of the washing drainage and the trough located below the trough. Has a downward slope on the upper surface,
A separating slant body whose lower end of the downward slanting portion forms a vertical flow path, and two baffles, a first baffle and a second baffle which are vertically installed above the downward slanting portion of the separating slanting body with their lower ends separated from each other. Provided, the first baffle is near the flow path, the second baffle is the first
Set up separately from the baffle toward the trough, and the upper end of the first baffle is below the water surface in the tower controlled by the trough, and the upper end of the second baffle is at the same level as the water surface in the tower controlled by the upper surface of the trough. A filtration device characterized by being positioned.