JPH0233915Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a flotation separation tank that floats and removes suspended solids from raw water containing suspended solids that are relatively easy to float.

<Prior Art> A flotation separation tank has conventionally been used to remove suspended solids that relatively easily float, such as fish protein or oil, from wastewater.

A conventional flotation separation tank is shown in Fig. 3, in which an inner cylinder 2 is provided inside the flotation tank 1, and an outer cylinder 3 is provided outside the inner cylinder 2. Raw water containing turbid substances flows in from a raw water inflow pipe 4 opened at the lower inside of the inner cylinder 2, and pressurized water in which a gas, such as air, is dissolved under pressure flows in from a pressurized water pipe 5 communicating with the raw water inflow pipe 4. , the air bubbles generated from the pressurized water and the suspended solids are combined, the floating suspended solids are floated above the flotation tank 1 as shown by the dotted arrow line, and the separated water from which the floating suspended solids have been removed is separated by the solid line. As shown by the arrow line, the inner circumferential edge of the flotation tank 1 is raised through the lower end of the outer cylinder 3, and the water flows out from the separation water pipe 7 through the water collection gutter 6 provided on the outer circumference of the flotation tank 1. In addition, the floating suspended solids 8 floating on the water surface of the flotation tank 1 are scraped into an introduction groove 10 provided in a part of the water surface of the flotation tank 1 by a scraper 9 rotated by a motor or the like (not shown). is discharged to the outside.

<Problems to be Solved> However, conventional flotation tanks have the following drawbacks.

First, since the bubbles generated and water create stirring turbulence inside the inner cylinder 2, the flocs of suspended matter attached to the bubbles may be separated by the turbulence, or the growth of the flocs may be hindered. On the contrary, this causes the flocs to become finer, which inhibits the formation of an efficient floating suspended solids layer.Secondly, the fluid rising from the inner cylinder 2 causes a rapid flow expansion near the water surface, which causes air bubbles to form. Adhering suspended matter is destroyed,
This reduces the flotation separation effect.

An object of the present invention is to eliminate such drawbacks of the conventional technology and to provide a flotation tank that can efficiently float and separate suspended solids.

<Means for solving the problem> The present invention does not directly flow raw water into the inner cylinder as in the conventional case, but instead flows the raw water from the lower part of the inner cylinder through a buttful plate, and then flows the raw water around the inner cylinder. The separated water is introduced from the upper end of the inner cylinder and taken out from the separated water intake mechanism provided inside the inner cylinder.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is an explanatory longitudinal cross-sectional view showing an example of an embodiment of the present invention, in which a cylindrical body 11 facing upward and widening at both ends is provided inside a flotation tank 1. By inserting the separated water take-out cylinder 12 with both ends open into the upper end opening, the lower end opening of the separated water take-out cylinder 12 is located inside the cylindrical body 11, and the separated water take-out cylinder 12 is The upper end is located above the water surface formed in the flotation tank 1. Further, a separated water outlet gutter 13 is provided close to the separated water surface formed in the separated water outlet tube 12, and one end of the separated water outlet tube 14 is communicated with the outlet gutter 13. In some cases, separated water outlet gutter 13
may be omitted and the opening of the separated water outlet pipe 14 may be provided directly close to the separated water surface. Further, a baffle plate 15 is provided below the lower end opening of the cylindrical body 11, an opening of the raw water inflow pipe 4 is provided below the buffle plate 15, and a pressurized water pipe 5 is provided in the raw water inflow pipe 4.
communicate. In addition, a collection groove 16 for floating suspended solids 8 is provided at the upper peripheral edge of the separated water take-out tube 12, and the collection groove 16 is connected to the collection groove 16 and has a length corresponding to the radius of the flotation tank 1 as shown in FIG. The introduction groove 10 is provided close to the water surface, and the floating suspended solids 8 are placed in the introduction groove 10.
A scraper 9 is installed for scraping. It is preferable to use the buff-full plate 15 described above in the shape of a cone or pyramid having an apex at the top.
In some cases, a simple plate-like material may be used. In the figure, 17 is a discharge pipe for floating suspended solids that communicates with the collection groove 16, and 18 is a blow pipe for precipitated substances.

<Effect> Next, the operation of the flotation tank of the present invention will be explained.

Raw water containing suspended matter and pressurized water in which a gas such as air is dissolved flow in from raw water inlet pipe 4 and pressurized water pipe 5, respectively. The pressurized water flowing in from the pressurized water pipe 5 is released from its pressurized state, and the air dissolved in the pressurized water in the raw water inflow pipe 4 or flotation tank 1 becomes fine bubbles, and the bubbles become suspended. The suspended solids that adhere to the substance become more easily floated, and the water containing the floating suspended solids collides with the baffle plate 15 and is introduced around the cylindrical body 11 . As shown by the dotted arrow line in the figure, the floating suspended solids 8 float to the water surface of the flotation tank 1, and as shown by the solid arrow line, the separated water flows through the upper end of the cylindrical body 11 to the cylindrical body. 11, then from the lower end of the separated water take-out tube 12, and is taken out from the separated water take-out pipe 14 via the separated water take-out gutter 13 to the outside.

Furthermore, if the separated water flowing into the cylindrical body 11 contains suspended solids that tend to settle due to insufficient adhesion of air bubbles, the suspended solids will be removed as shown by the dashed-dotted arrow line. The material is allowed to settle in the cylindrical body 11, flowed out from the lower end of the cylindrical body 11, and brought into contact with air bubbles again to form suspended suspended matter that easily floats.

Note that if the cylindrical body 11 is directed upward and widened at the end as shown in the drawing, the separated water will flow into the cylindrical body 11.
It becomes easier to flow in from the upper end, and by narrowing it downward, the sedimentation flow rate of the suspended matter that settles inside the cylindrical body 11 can be increased, and the installation area of the buff-full plate 15 can be made smaller. However, in some cases, the cylindrical body 11 may be a simple cylinder or a rectangular cylinder.

On the other hand, the floating suspended solids 8 floating on the water surface are scraped into the introduction groove 10 by a rotating scraper 9, then collected in the collection groove 16, and then taken out from the discharge pipe 17. Further, if sediment accumulates at the bottom of the flotation tank 1, it is occasionally discharged to the outside through the blow pipe 18.

<Effects> As explained above, the present invention guides the raw water containing suspended solids from below the cylindrical body 11 to the periphery of the cylindrical body 11 via the buff-full plate 15, so that it is not possible to cause a sudden drop near the water surface as in the conventional case. Since the flow does not spread, turbulence does not occur, and a low-velocity and stable upward flow can be created outside the cylindrical body 11.
Suspended substances attached to air bubbles can be effectively separated by flotation without being destroyed. Also, the cylindrical body 11
The suspended matter descending inside flows out from the lower end of the cylindrical body 11 and is brought into contact with the rising fluid again on the outside of the lower end of the cylindrical body 11, so that air bubbles can be attached to the suspended matter again. Therefore, compared to conventional devices, there are more opportunities to come into contact with air bubbles, so suspended matter can be floated more effectively.

[Brief explanation of drawings]

FIG. 1 is an explanatory longitudinal cross-sectional view of the flotation layer of the present invention, FIG. 2 is a top view of FIG. 1, and FIG. 3 is an explanatory longitudinal cross-sectional view of a conventional flotation tank. 1...Flotation tank, 2...Inner cylinder, 3...Outer cylinder, 4...
... Raw water inflow pipe, 5 ... Pressurized water pipe, 6 ... Water collection gutter,
7...Separation water pipe, 8...Floating suspended solids, 9...Scraper, 10...Introduction groove, 11...Cylindrical body, 12...
...Separated water take-out tube, 13...Separated water take-out gutter, 14...
...Separated water outlet pipe, 15...Bullet plate, 16...
Collection groove, 17...discharge plate, 18...blow pipe.

Claims (1)

[Scope of utility model registration request] By installing a cylindrical body with both ends open in the flotation tank, and inserting a separated water take-out cylinder with both ends open into the upper end opening of the cylindrical body, the lower end of the separated water take-out cylinder is opened. is located inside the cylindrical body, and the upper end of the separated water take-out tube is located above the water surface formed in the flotation tank, and the separated water is placed close to the separated water surface formed in the separated water take-out tube. It has a structure in which an opening for a take-out pipe is provided, and an opening for a raw water inflow pipe is provided below the opening at the bottom end of the cylindrical body via a baffle plate. The suspended solids in the raw water are guided to the outside to float to the water surface of the flotation tank, and the separated water is led to the upper end opening of the cylindrical body and then to the lower end opening of the separated water take-out tube, and then flows out from the separated water take-out pipe. A flotation separation tank characterized by: