JP2590515Y2 - A device for preventing circulation flow by air bubbles in a gravity filtration pond - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a gravity filtration pond (including an adsorption pond) used for various kinds of water treatment.

[0002]

2. Description of the Related Art Conventionally, for example, as a gravity filtration pond for water purification treatment, a granular filter medium (b) is filled into a pond body (a) to a required thickness as shown in FIG. The raw water that has flowed over the overflow seki (d) from the raw water supply channel (c) arranged at the upper part is caused to flow down into the raw water inflow pipe (e) by gravity, and from the inlet (f) on one side wall of the pond main body into the pond. Those having a structure that allows inflow are widely used.

[0003]

However, in the conventional gravity filtration pond, when the raw water flowing from the raw water supply passage (c) flows into the raw water inflow pipe (e), the raw water is entrained in air to form bubbles. As the raw water flows down into the pond from the inflow port (f), the bubbles are released into the raw water in the pond, and the released bubbles rise in the raw water in the pond, causing a local upward flow. As a result, as shown by an arrow in FIG. 4, the water rises on one side of the pond, then the water surface goes down to the other side, and then goes down on the other side,
Next, a circulating flow is generated that flows to one side on the upper surface of the filter medium (b),
Due to this circulation flow, the filter medium (b) gradually moves to one side, and as a result, as shown by the phantom line, there is a disadvantage that the packing thickness becomes extremely non-uniform and the filtering action is reduced.
This drawback is particularly when using a granular filter medium such as activated carbon or anthracite that has a low specific gravity and is easy to move.
It is remarkable because the biasing of the filter medium by the circulating flow is easily performed, and in the case of a natural equilibrium filtration pond in which the water level difference between the overflow seki and the pond water level in the initial stage of the filtration process is large, it is large because the air entrainment is severe. Had become.

[0004] As a countermeasure, a method of providing an apparatus for separating air in raw water outside the pond or a method of increasing the diameter of the raw water inflow pipe and reducing the flow velocity in the pipe to prevent air entrapment can be considered. However, these methods are large and require strength, and the latter has a problem that the raw water inflow pipe and the inflow valve have large diameters, and both methods increase the equipment cost.

SUMMARY OF THE INVENTION It is an object of the present invention to suppress the occurrence of the circulating flow with a simple structure and to prevent the filter medium from shifting.

[0006]

As a means for solving the above-mentioned problems, the present invention relates to a raw water in a pond body filled with a filter material and an adsorbent to a required thickness, and a raw water containing bubbles is supplied to a raw water inflow pipe. At the gravity type filtration pond supplied from the raw water inlet through the upper and lower ends of the upper and lower openings that extend from the raw water in the pond to at least the surface of the raw water in the pond, in order to guide bubbles rising from the raw water inlet into the pond raw water in an isolated state We propose a device to prevent circulating flow caused by air bubbles in a gravity filter with an air bubble isolation tube.

[0007] In the present invention, the above "filtration pond" is used as a term including an adsorption pond. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, a filter medium frame (2) is formed inside a box-shaped pond main body (1) having an open upper surface, and the filter medium frame (2) is formed.
A filter bed (3) is arranged at the bottom of the inside, and a granular filter medium such as activated carbon, anthracite, sand or the like is filled to a required thickness to form a filter medium layer (4). Near the bottom of one side wall, there is provided a treated water outlet (5) opening to the filter bed (3), to which a treated water outlet pipe (6) is connected.
A raw water supply path (7) for guiding raw water is installed at a high position on the other side of the pond main body (1), and an overflow tank is provided on one side of the supply path (7) through an overflow overflow (8). (9) is connected, one end of the raw water inflow pipe (11) is connected to an outlet (10) opened at the bottom of the overflow tank (9), and the outlet is dropped. The end is connected to the raw water inlet (12) opened at the middle of the other side wall of the pond main body (1). (1
3) is a raw water inflow valve connected to the middle of the inflow pipe (11).

In the pond main body (1) of the gravity type filtration pond having the above structure, a trough-shaped isolating material (1) curved in a semicircular arc is formed on the inner surface of one side wall having the raw water inlet (12).
4) is mounted in a vertical state surrounding the inflow port (12) and projecting slightly above the water surface from the inflow port (12), whereby the separating member (14) and the side wall of the pond main body are connected. The upper and lower openings (1
6) and (17) of the bubble isolation cylinder (15) are formed.

[0010] Now, Seki (8) overflowing from the raw water supply channel (7)
The raw water flowing into the overflow tank (9) after flowing through the raw water inflow pipe (11) while discharging air bubbles from the inflow port (12) while entraining air from the outflow port (10).
5) When the air bubbles flow into the space, the released air bubbles are released from the air bubble isolating tube (1).
5) As soon as it rises inside, the water surface in the bubble isolating tube (15) is raised by the isolating material (14).
Since it is isolated from the outside water surface in the pond, the circulation flow over the entire pond due to the rise of the air bubbles is not generated, and therefore, the filter medium layer (4) is not adversely affected. Bubbles rising in the isolation cylinder (15) are released into the atmosphere through the opening (16) at the upper end of the isolation cylinder, and are also released to the isolation cylinder (15).
The raw water that has flowed into the chamber and separated bubbles is
Merge with Ikeuchi raw water through 7).

A large number of holes or slits are formed in the side wall of the separating member (14) at a position relatively deeper than the water surface in the pond, and the raw water flows into the separating cylinder (15) and is separated from the bubbles. Or a large part of the water may merge with the raw water in the pond from the hole or the slit.

Another embodiment of FIG. 2 is a raw water inflow pipe (11).
a) directly into the pond and the lower end opening (17a)
Then, a cylindrical separator (14a) having a small opening (16a) at the closed upper end is attached concentrically to the outer periphery of the inflow pipe (11a), and the other structure is substantially the same as that of FIG. is there.

In another embodiment shown in FIG. 3, the distal end of the raw water inflow pipe (11b) is advanced into the pond and the inflow port (12).
b) is bent upward, and the filter medium layer (4b) fills the entire inner surface of the pond body (1b), and other structures are substantially the same as those in FIG.

[0014]

According to the device for preventing circulation flow by bubbles in the gravity filtration pond of the invention, the generation of the circulation flow by bubbles in the pond is suppressed by a simple structure in which a bubble isolation tube is simply provided in the pond. It is possible to prevent the filter medium from being biased in the pond.

[Brief description of the drawings]

FIG. 1 is a front view, partially cut away, of a filtration pond in which the present invention is implemented.

FIG. 2 is a longitudinal sectional front view of another embodiment.

FIG. 3 is a partially cut-away vertical front view of still another embodiment.

FIG. 4 is a schematic vertical front view of a conventional filtration pond.

[Explanation of symbols]

 1, 1a, 1b Pond main body 4, 4a, 4b Filter media layer 11, 11a, 11b Raw water inlet pipe 12, 12a, 12b Raw water inlet 15, 15a, 15b Bubble isolation cylinder 16, 16b, 17, 17a, 17b Opening 16a Small Opening

Claims (1)

(57) [Scope of request for utility model registration] 1. A gravity filtration pond for supplying raw water containing air bubbles from a raw water inlet through a raw water inflow pipe into raw water in a pond body filled with a filter medium and an adsorbent to a required thickness. Circulating flow due to air bubbles in a gravity filtration pond equipped with bubble isolation cylinders with upper and lower openings that extend from the raw water in the pond to at least the surface of the raw water in the pond to guide the bubbles released from the inlet into the raw water in the pond in an isolated state Prevention device.