JP2002316003A - Gradient plate precipitator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gradient plate precipitator which allows air bubbles generated by air cleaning to uniformly ascend along the rear surface of a gradient plate by disposing holes on a reinforcing member which is fixed to the gradient plate, as a result, generates a downward water stream on other gradient plates, smoothly slides flocs attached to the gradient plate downward and removes the same. SOLUTION: In this gradient plate precipitator, a plurality of gradient plates 11 are separated with a prescribed space and are juxtaposed, and the reinforcing members 12 for reinforcing the gradient plates 11 are fixed on the rear surfaces of the gradient plates 11. Therein, further, the holes 13 for passing the air bubbles supplied from the lower side of the gradient plates 11 are disposed along the gradient plates 11 on the reinforcing members 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inclined plate settling device installed in a sedimentation pond of a water treatment facility such as a water supply facility, and more particularly to a floc attached to the inclined plate due to bubbles generated during air washing. The present invention relates to an inclined plate sedimentation device capable of sliding down to remove.

[0002]

2. Description of the Related Art In a water treatment facility such as a water supply facility, raw water introduced from a river or the like is subjected to a water purification treatment through an impurity aggregation process, a sedimentation process, a filtration process, a sterilization process and the like. In the above-mentioned precipitation step, a precipitation basin for precipitating and removing impurities contained in the raw water is provided. In the precipitation step,
The impurities contained in the raw water are removed by causing the agglomeration of impurities (hereinafter referred to as flocs) formed in the impurity aggregation step to settle at the bottom of the sedimentation basin.

In general, a sedimentation basin for performing a sedimentation step is provided with an inclined plate sedimentation device or an inclined tube sedimentation device. Among them, the inclined plate sedimentation device is configured by arranging a number of inclined plates in parallel. is there. Here, the floc removal capacity of the sedimentation basin is represented by the surface load factor, that is, the value obtained by dividing the flow rate of the water to be treated by the bottom area of the sedimentation basin. Is improved. That is, the larger the bottom area of the sedimentation basin, the higher the ability of the sedimentation basin to remove flocs. And, as described above, since the inclined plate sedimentation device is provided with a large number of inclined plates, the bottom area of the sedimentation basin can be substantially increased by depositing flocs on the inclined plates. Therefore, the inclined plate sedimentation apparatus makes it possible to greatly improve the ability of the sedimentation basin to remove flocs. Also, by installing the inclined plate sedimentation device in the sedimentation basin, the flow of the water to be treated in the sedimentation basin can be adjusted to a quiet and uniform flow, preventing the flocks from winding up due to the uneven flow, and reducing the number of flocs. It is possible to surely settle at the bottom of the sedimentation basin.

FIG. 5A is a perspective view showing an inclined plate and a reinforcing member constituting a conventional inclined plate settling apparatus. The inclined plate sedimentation device is configured by arranging a plurality of inclined plates 11 inclined at a predetermined angle, and on the back surface of each inclined plate 11, two separated reinforcing members 33 are attached. Is fixed so as to be parallel to one side. The inclined plate 11 and the reinforcing member 33 are formed from a rectangular flat plate.

The water to be treated flows from the direction A into the flow path between two adjacent inclined plates 11, and the flocs settling in the treated water settle on the surface of the inclined plate 11. As described above, since the inclined plate 11 is installed at an angle,
The floc settled on the inclined plate 11 slides down on the surface of the inclined plate 11, sinks further from the lower end of the inclined plate 11, and settles on the bottom of the sedimentation basin.

[0006] As the floc sedimentation removal operation by the inclined plate sedimentation device progresses, the remaining flocs that do not slide down and accumulate on the inclined plate accumulatively. Therefore, it is necessary to periodically clean the inclined plate. Becomes As a method for cleaning the inclined plate, there is a method by air cleaning, and this air cleaning generates continuous bubbles below the inclined plate sedimentation device, and by applying the bubbles to the inclined plate, the flocs attached to the inclined plate are removed. To get rid of it.

[0007]

In the conventional inclined plate sedimentation apparatus, as shown in FIG. 5 (b), bubbles supplied from below the inclined plate sedimentation device during the air cleaning process are applied to the back surface of the inclined plate 11. The upward movement is blocked by the reinforcing member 33 fixed to the side surfaces of the inclined plate 11 along the reinforcing member 33.
Since the air bubbles escaped from e and 11e, the air bubbles could not be uniformly dispersed. As a result, since no downward water flow is generated on the surface of the other inclined plate that is arranged side by side opposite to the back surface of the inclined plate, the flocs attached to the surface of the inclined plate cannot slide down. The flocs were separated by the rising bubbles and were completely mixed in the water to be treated.

[0008] The present invention has been made in view of the above points, and by providing a hole in the reinforcing member fixed to the inclined plate, air bubbles generated by air cleaning are uniformly raised on the back surface of the inclined plate. As a result, there is provided an inclined plate sedimentation device capable of generating a downward water flow on the surface of another inclined plate and smoothly sliding down and removing the flock attached to the inclined plate downward. The purpose is to do.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a plurality of inclined plates which are arranged side by side at predetermined intervals, and the inclined plates are reinforced on the back surface of the inclined plates. In the inclined plate sedimentation device to which the reinforcing member for fixing is attached, the reinforcing member is provided along the inclined plate with a hole for passing bubbles supplied from below the inclined plate. It is characterized by having. Further, in one aspect of the present invention, the reinforcing member is provided with a plurality of holes at predetermined intervals for passing bubbles supplied from below the inclined plate.

According to the present invention, air bubbles supplied from below the inclined plate sedimentation device at the time of air cleaning pass through the holes provided in the reinforcing member, and return to the back surface of the inclined plate. Can be continued up to the upper end, so that the flow of rising bubbles can be uniformly generated on the entire back surface of the inclined plate. As a result, a difference occurs between the density of the water to be treated in the vicinity of the back surface of the inclined plate and the density of the water to be treated in the vicinity of the surface of the other inclined plate that is arranged side by side facing the back surface of the inclined plate. A downward water flow is generated on the surface of the other inclined plate, and the downward water flow makes it possible to slide down and remove the flocs attached to the surface of the other inclined plate. Since the upward flow and the downward water flow of the bubbles are generated in the respective inclined plates, it is possible to remove the flocks of all the inclined plates installed in the inclined plate settling apparatus.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of an inclined plate settling apparatus according to the present invention will be described with reference to the drawings. FIG.
1 is a schematic sectional view of an entire sedimentation basin in which an inclined plate sedimentation apparatus according to the present invention is installed.

In a water treatment facility such as a water supply facility, a sedimentation basin 2 for performing a sedimentation step is provided. This sedimentation basin 2
Has a horizontally long structure to prevent drifting of the water 6 to be treated in the pond and to give straightness to the flow of the water 6 to be treated. At the front end of the sedimentation basin 2, an inflow port 3 for guiding the treated water 6 having undergone the impurity coagulation step to the sedimentation basin 2 is provided, and rectifying plates 4 are provided at the front and rear in the sedimentation basin. . In the vicinity of the center of the sedimentation basin, an inclined plate settling device 1 in which a plurality of inclined plates according to the present invention are juxtaposed is installed.
The floc settled on the inclined plate slides down on the inclined plate and accumulates on the bottom of the sedimentation basin 2. It is installed at a height of a predetermined distance. At the rear end of the sedimentation basin 2, there is provided an outflow weir 5 for the water 6 to be treated after the sedimentation step.

The water 6 to be treated guided into the sedimentation basin 2 from the direction B is supplied to the flow rectifying plates 4 provided at the front and rear of the sedimentation basin 2 so that the flow rate of the water 6 to be treated is one in all cross sections in the sedimentation basin. It is rectified so that it flows down the pond. The floc having a high sedimentation speed directly settles at the bottom of the sedimentation basin before flowing into the inclined plate sedimentation device 1, while the floc having a low sedimentation speed flows into the inclined plate sedimentation device 1 and settles on the surface of the inclined plate. The floc settled on the surface of the inclined plate slides on the surface of the inclined plate and settles on the bottom of the sedimentation basin. In this way, after many flocs have settled at the bottom of the sedimentation basin and the inclined plate sedimentation device 1, the water 6 to be treated is drained from the outflow weir 5 and flows into the filtration pond which is the next step.

Next, an inclined plate settling apparatus according to the present invention will be described with reference to FIG. FIG. 2A is a perspective view of an inclined plate and a reinforcing member constituting the inclined plate settling device according to the present invention, and FIG. 2B is an inclined plate installed in the inclined plate settling device according to the present invention. FIG.

As shown in FIG. 2 (b), the inclined plate settling device comprises a plurality of inclined plates 11, and each inclined plate 11
Are arranged side by side at a predetermined angle θ with respect to the horizontal direction so that the surface 11a of the inclined plate faces upward in order to settle the flocks that settle on the inclined plate. In addition,
The inclination angle θ of the inclined plate 11 is preferably set to about 60 ° in order to secure an area for sedimenting the flocs and to smoothly slide the flocs settled on the inclined plate surface 11a.

As shown in FIG. 2A, the back surface 11 of the inclined plate
b, two reinforcing members 12 that are separated from each other,
Is attached so as to be parallel to one side in the longitudinal direction. The inclined plate 11 and the reinforcing member 12 are formed of a rectangular flat plate, and the reinforcing member 12 is provided with a plurality of holes 13 for passing bubbles at predetermined intervals. In the embodiment of the present invention, the length of the reinforcing member 12 is the same as the length of one side in the longitudinal direction of the inclined plate 11, but does not necessarily have to be the same length.

Next, the operation of the present invention when the inclined plate settling apparatus according to the present invention is cleaned with air will be described with reference to FIG. 3A and 3B are a perspective view and a side view of the inclined plate showing the flow of bubbles and flocs when the inclined plate settling apparatus according to the present invention is cleaned with air. An air cleaning device 24 that generates continuous bubbles 21 is provided below the inclined plate settling device. As shown in FIG. 3A, the air bubbles 21 generated from the air cleaning device 24 hit the vicinity of the lower end of the inclined plate back surface 11b, and thereafter, the inclined plate back surface 11b
Along the direction C, passes through the holes 13 provided in each reinforcing member 12, reaches the upper end of the inclined plate rear surface 11b, and then further rises. As described above, the bubbles rise through each of the holes 13 provided at regular intervals, so that the flow of the bubbles can be uniformly dispersed on the rear surface of the inclined plate rear surface 11b.

As described above, a downward water flow is generated in the direction D on the surface of another inclined plate provided opposite to the back surface side of the inclined plate 11, so that the downward water flow The flock 23 attached to the surface of the inclined plate slides down in the direction D and is removed.

Next, an experimental example performed using the inclined plate sedimentation apparatus according to the present invention will be described with reference to FIG. FIG.
4A is a rear view of a state in which three reinforcing members 12 are fixed to the inclined plate 11, and FIG. 4B is a II view of FIG. 4A.
FIG. 4C is a sectional view taken along the line II-II of FIG. 4A, and FIG. 4D is an enlarged view of a hole provided in the reinforcing member.

In this experimental example, W = 20 as the inclined plate 11
A flat plate of 00 mm, L = 214 mm, and H = 1.5 mm was used. On the back surface of the inclined plate 11, three reinforcing members 12 are fixed at an interval of 77 mm in parallel with one side in the longitudinal direction of the inclined plate 11.

As shown in FIG. 4B, each reinforcing member 12 has a horizontally elongated hole 13 of 5 mm × 15 mm.
Nineteen are provided at intervals of 100 mm. That is, 19 pieces × 3 pieces per 2000 mm long inclined plate
A total of 57 holes of the reinforcing members are provided.

In this experimental example, an experiment was conducted in two sedimentation ponds. One of the sedimentation basins was provided with 36,000 inclined plates 11, and the other sedimentation basin was provided with 1,300 inclined plates 11. Observation was made on the flow of air bubbles and the flow rate of air bubbles when air-cleaning No. 11 was performed. As a result, the inclined plate 1
The bubbles supplied from below 1 passed through a total of 57 holes provided in the reinforcing member 12, and it was confirmed that the bubbles were uniformly dispersed on the entire back surface of the inclined plate 11. The amount of air passing through the hole at this time is 3.0 l / min.
Met.

[0023]

As described above, according to the present invention,
During the air washing, the flocs adhering to the inclined plate surface can be smoothly slid down to the bottom of the sedimentation basin and sufficiently removed.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an entire sedimentation basin in which an inclined plate sedimentation apparatus according to the present invention is installed.

FIG. 2A is a perspective view of an inclined plate and a reinforcing member constituting the inclined plate sedimentation apparatus according to the present invention, and FIG.
(B) is an arrangement view of the inclined plate installed in the inclined plate settling apparatus according to the present invention.

FIGS. 3 (a) and 3 (b) are a perspective view and a side view of the inclined plate showing the flow of bubbles and flocs when the inclined plate settling apparatus according to the present invention is cleaned with air.

FIG. 4 (a) is a rear view of a state in which a reinforcing member is fixed to an inclined plate, and FIG. 4 (b) is a II view of FIG. 4 (a).
FIG. 4C is a sectional view taken along line II-II of FIG. 4A, and FIG. 4D is an enlarged view of a hole provided in the reinforcing member.

FIG. 5 (a) is a perspective view showing an inclined plate and a reinforcing member constituting a conventional inclined plate settling apparatus, and FIG. 5 (b).
FIG. 4 is a view showing a flow of bubbles when a conventional inclined plate sedimentation apparatus is cleaned with air.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 inclined plate sedimentation device 2 sedimentation basin 3 inflow port 4 straightening plate 5 outflow weir 6 water to be treated 7 gantry 11 inclined plate 11 a inclined plate surface 11 b inclined plate back surface 11 e inclined plate side surface 12 reinforcing member 13 hole 21 bubble 23 floc 24 air Cleaning device 33 Conventional reinforcement member

Continued on the front page (72) Inventor Koji Matsunobu 11-1 Haneda Asahimachi, Ota-ku, Tokyo Inside the Ebara Corporation (72) Inventor Yutaka Kodita 11-1 Haneda Asahi-cho, Ota-ku, Tokyo Ebara Corporation Inside of Nidec

Claims (2)

[Claims] 1. An inclined plate sedimentation device in which a plurality of inclined plates are juxtaposed at predetermined intervals and a reinforcing member for reinforcing the inclined plate is fixed to a back surface of the inclined plate. The inclined plate sedimentation device according to claim 1, wherein the reinforcing member is provided with holes along the inclined plate for passing bubbles supplied from below the inclined plate. 2. The inclined member according to claim 1, wherein the reinforcing member is provided with a plurality of holes at predetermined intervals for passing bubbles supplied from below the inclined plate. Plate sedimentation equipment.