JP3548105B2 - Pressure flotation device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention belongs to the technical field of a pressure flotation device.
[0002]
[Prior art]
Supplying a pressurized gas-water mixture fluid to the flotation / separation tank into which raw water has been introduced to generate fine bubbles derived from the gas-water mixture fluid, and to cause floating substances contained in the raw water to float along with the fine bubbles. 2. Description of the Related Art A pressurized flotation device for performing solid-liquid separation by using a pressurized liquid is known.
[0003]
For example, JP-A-10-85722 discloses a flotation / separation tank, a raw water intake pump having a suction side connected to a raw water source and a delivery side connected to a flotation / separation tank, and a suction side connected to a raw water source and a delivery side connected to an air saturation tank. (Pressurized tank) connected to a water intake pump, a compressor that feeds air to raw water in an air saturation tank, and a pressurized flotation equipped with a pipe that jets water with supersaturated air from the air saturation tank to the flotation separation tank An apparatus is described.
[0004]
[Problems to be solved by the invention]
In the conventional pressure flotation device, at least a pressurized tank and a compressor are required, and the size of the device cannot be avoided. Although not disclosed in JP-A-10-85722, a coagulant or a pH adjuster may be added to raw water. In this case, a chemical tank is provided between a water intake pump and a raw water source. It had to be installed, and the device was becoming larger.
[0005]
In addition, the flow rate and pressure to be ejected from the pressurized tank to the flotation tank must be adjusted according to the condition of the raw water and the amount of treatment, but it is extremely difficult to automatically control this, requiring a dedicated operator. Was.
That is, the conventional pressure flotation device is large and has problems in operability and running cost.
[0006]
Means for Solving the Problems and Effects of the Invention
The pressurized flotation device according to claim 1 for solving the above-mentioned problem is to supply a pressurized gas-water mixed fluid to a flotation / separation tank into which raw water is introduced to remove fine bubbles derived from the gas-water mixed fluid. In a pressurized flotation device that generates and causes solid-liquid separation by causing the floating substance contained in the raw water to float along with the fine bubbles,
A feed well erected at the center of the bottom of the flotation tank, the lower end of which is closed; a raw water supply nozzle that opens to the side of the flotation tank to eject the raw water into the flotation tank; A baffle (27a) erected at the bottom between the well and a well, and a take-out nozzle erected through the bottom of the levitation tank to allow water in the middle layer of the levitation tank to flow through an opening at the upper end. A baffle (27b) erected at the bottom between the feed well and a suction side connected to the floating separation tank outside the feed well and a delivery side connected to the floating separation tank inside the feed well; A circulation pump connected to the circulation pump, gas supply means for supplying gas to the suction side of the circulation pump, and a delivery pipe from the delivery side of the circulation pump to the flotation tank. Characterized in that a is a line mixer.
[0007]
The pressurized flotation device adds a gas such as air from a gas supply means to water (raw water) sucked from a flotation tank by a circulation pump and discharges the water.
The circulating water discharged from the circulation pump is a gas-water mixed fluid of gas and water, and the gas-water mixed fluid is agitated by a line mixer to make the gas bubble diameter extremely small (for example, 0.5 to 0.5). (About 3 μm). When the gas-water mixed fluid is discharged into the flotation tank, the gas contained therein rises as bubbles and accompanies fine suspended substances (so-called SS) contained in the raw water in the flotation tank. Surface. The floated SS floats on the water surface and aggregates with each other, so that it hardly re-sediments. For example, it may be scraped and taken out of the flotation tank.
[0008]
Since only circulating water mixed with gas is sent to the flotation tank, even if a new gas supply means and a line mixer are required (the circulating pump corresponds to a conventional intake pump), the pressurized tank and the No compressor is required. Therefore, the size of the pressure flotation device can be reduced. Since the line mixer becomes a part of the piping, the size of the apparatus is not increased.
[0009]
The gas supply means may be configured such that, for example, a valve such as a needle valve is attached to a branch pipe provided on the suction side pipe of the circulation pump and gas flows through the valve, and the apparatus does not become large. In particular, when air is used as the gas, if one end of the valve is opened to the atmosphere, the air is sucked at a negative pressure by the circulation pump, so that the configuration becomes very simple. Note that the valve may be a globe valve or a gate valve, but a needle valve is optimal for adjusting the amount of inflow of gas.
[0010]
Since only water is circulated by the circulation pump, no special pressure control or flow rate control is required, so that automatic operation becomes possible, and there is no need to attach a dedicated operator.
As described above, the apparatus can be reduced in size, and the operability and running cost can be extremely improved.
[0011]
The gas supplied to the suction side of the circulating pump is not particularly limited. If air is used as described above, the configuration is simplified and the running cost for supplying the gas is not required.
However, when chemical water quality improvement is required, air may not be enough. The configuration described in claim 2 addresses this, and the pressure flotation device according to claim 1 is characterized in that ozone generated by an ozone generator is supplied from the gas supply means.
[0012]
By supplying ozone from the suction side of the circulation pump, ozone dissolved in the raw water decomposes organic compounds and the like contained in the raw water, so that the water quality is improved. By employing ozone, chemical water quality can be improved (for example, COD can be improved), and the injection of chemicals for that purpose can be eliminated or reduced.
[0013]
Ozone generators are extremely small in size as compared to compressors and pressurized tanks, and their product prices are low. In addition, since ozone uses oxygen in the air as a raw material, there is no need to purchase raw materials even if operating power for the ozone generator is required .
[0014]
The pressure flotation device according to the first aspect of the present invention includes a feed well that is erected at the center of the bottom of the flotation / separation tank and has a closed lower end. The suction side of the circulation pump floats outside the feed well. Since it is connected to the separation tank and the delivery side is connected to the flotation separation tank inside the feed well, a rising water flow is formed by fine bubbles, and the circulation in the flotation separation tank can be performed well. Further, by appropriately selecting the size and shape of the feed well, there is an advantage that the rising speed of the fine bubbles can be a speed at which the SS adsorption efficiency is good.
In addition, the same effect as the conventional feed well can be obtained by discharging the circulating water into the feed well by the circulating pump, and the water can be taken in from the outside of the feed well and discharged into the feed well. And the effect of chemical water quality improvement can be further improved.
Further, a baffle (27a) erected at the bottom between the feed water supply nozzle and the feed well, which is opened on the side surface of the flotation tank and spouts the raw water into the flotation tank, is used for the raw water spouting from the raw water supply nozzle. Between the feed nozzle and the feed well, which is prevented from directly entering the feed well side, stands upright through the bottom of the flotation tank, and drains middle layer water of the flotation tank from the opening at the upper end . The baffle (27b) erected at the bottom alleviates the movement of water on the feed well side affecting the water near the discharge nozzle.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to examples of the present invention.
[0016]
【Example】
As shown in FIG. 1, the pressure flotation device 10 includes a flotation / separation device 20 including a flotation / separation tank 21 and a treated water tank 22, an ozone mixing pump 50, an ozone generator 60, a line mixer 70, and the like.
[0017]
As shown in detail in FIG. 2, a feed well 23 is provided upright at the bottom of the flotation separation tank 21, and a scraping machine 24 is provided at the top. A raw water supply nozzle 25 is provided on one side surface of the flotation tank 21, and an extraction nozzle 26 is provided inside. The take-out nozzle 26 penetrates the bottom of the floating separation tank 21 and reaches the treatment water tank 22, and the upper level of the take-out nozzle 26, that is, middle-layer water of the floatation separation tank 21 can flow out to the treatment water tank 22.
[0018]
Baffles 27a and 27b are provided between the feed well 23 and the feed well 23 and the feed well 23. The baffle 27a prevents the raw water spouting from the raw water supply nozzle 25 from directly entering the feed well 23 side, and the baffle 27b affects the movement of the water on the feed well 23 side to the water near the extraction nozzle 26. It alleviates the problem.
[0019]
The scraping machine 24 is provided with a large number of scraping plates (not shown), and can rotate the clockwise direction in FIG. 2 to scrape aggregates of SS floating in the upper layer. An inclined plate 28 is provided inside the flotation separation tank 21 corresponding to the scraping position, and a scum receiver 29 for receiving the scraped-out aggregate is provided outside the inclined plate 28.
[0020]
As shown in FIG. 1, a pump 33 is provided in the treated water tank 22, and the treated water can be sent out by the pump 33 and sprayed from the defoaming pipe 34 to the scum receiver 29. This water spray is used for defoaming in the scum receiver 29. The effluent from the scum receiver 29 is discharged to sewage.
[0021]
Since this embodiment is an example in which the present invention is applied to cleaning water treatment for screen plate making, the water in the processing water tank 22 is sent to the cleaning step and used as cleaning water. It is returned to the water tank 80.
As shown in FIG. 3, a circulating water suction pipe 31 is drawn out from the bottom of the flotation tank 21 and connected to the suction side of the ozone mixing pump 50. Although not shown in FIG. 3, a needle valve 31b is attached to the cheese 31a of the circulating water suction pipe 31, and a pipe from the ozone generator 60 is connected through the needle valve 31b as shown in FIG. ing. Thereby, the ozone from the ozone generator 60 is supplied to the suction side of the ozone mixing pump 50. Note that a gas supply unit is configured by the cheese 31a and the needle valve 31b.
[0022]
On the other hand, a circulating water discharge pipe 32 reaching the feed well 23 is connected to the delivery side of the ozone mixing pump 50, and a line mixer (static mixer) 70 is incorporated in a part of the pipe 32.
With such a configuration, if the ozone mixing pump 50 is operated while water is put in the floatation / separation tank 21, water in the floatation / separation tank 21 is sucked from the circulating water suction pipe 31 and fed from the circulating water discharge pipe 32. It can be discharged into the well 23.
[0023]
If the ozone generator 60 is operated at that time, ozone is supplied to the suction side of the ozone mixing pump 50, and the ozone and water are mixed in the ozone mixing pump 50, and further stirred and mixed by the line mixer 70. By doing so, the bubble diameter of ozone can be made very small (about 1 μm in this embodiment). That is, the water discharged into the feed well 23 contains fine bubbles of ozone.
[0024]
As shown in FIG. 3, there are two systems of the circulating water discharge pipe 32 including the ozone mixing pump 50, the circulating water suction pipe 31, and the line mixer 70, but FIG. 1 shows only one system.
As shown in FIG. 1, a raw water delivery pump 81 is installed in the raw water tank 80, and the raw water delivered by the raw water delivery pump 81 is sent to the raw water supply nozzle 25 of the flotation tank 21 via the raw water pipe 82. . Further, a sludge extraction pump 83 is provided at the bottom of the raw water tank 80 so that the sludge accumulated in the raw water tank 80 can be sent out to the sewage.
[0025]
The pressurized flotation device 10 adds the ozone from the ozone generator 60 to the water (raw water) sucked out of the flotation / separation tank 21 by the ozone mixing pump 50, and agitates with the line mixer 70 to greatly reduce the ozone bubble diameter. It is made smaller and discharged to the feed well 23.
[0026]
The circulating water discharged from the feed well 23 is a gas-water mixed fluid of ozone and water (ozone mixed water), and the bubble diameter of ozone is extremely small (1 μm in this embodiment) by stirring in the line mixer 70. Before and after). When the ozone bubbles are discharged into the feed well 23, the ozone bubbles rise and fine floating substances (so-called SS) contained in the raw water in the flotation / separation tank 21 are caused to float. The floated SS floats on the water surface and aggregates with each other, so that it hardly re-sediments. It is scraped by the scraper 24 and discharged from the scum receiver 29 to the sewage. Thereby, SS is removed from raw water, and water quality is improved.
[0027]
In addition, ozone dissolved in the circulating water decomposes organic compounds and the like contained in the raw water, so that the water quality is improved.
Since only the circulating water mixed with ozone is sent to the flotation tank 21, even if the ozone generator 60 and the line mixer 70 are newly required, the pressurized tank and the compressor in the conventional pressurized flotation apparatus are required. And not. Therefore, the pressure flotation device 10 can be reduced in size. In addition, the ozone generator 60 is extremely small compared to a compressor or a pressurized tank, and the product price is low. Further, since the line mixer 70 becomes a part of the piping, the size of the apparatus is not increased.
[0028]
Since only water is circulated by the ozone mixing pump 50 and no special pressure control or flow rate control is required, automatic operation becomes possible, and there is no need to attach a dedicated operator.
In addition, by employing ozone instead of the conventional air, chemical water quality can be improved (for example, COD can be improved), and the injection of chemicals for that purpose can be eliminated or reduced. Further, since ozone uses oxygen in the air as a raw material, there is no need to purchase raw materials even if operating power for the ozone generator 60 is required.
[0029]
As described above, the apparatus can be reduced in size, and the operability and running cost can be extremely improved.
In addition, by providing the feed well 23, a rising water flow is formed by fine bubbles, and the circulation in the flotation separation tank 21 can be favorably performed. Also, by appropriately selecting the size and shape of the feed well 23, there is an advantage that the rising speed of the fine bubbles can be made a speed at which the SS adsorption efficiency is good.
[0030]
The circulating water suction pipe 31 on the suction side of the ozone mixing pump 50 is connected to the outside of the feed well 23, and the circulating water from the circulating pump is discharged to the inside of the feed well 23. The effect of the improvement can be further improved.
[0031]
As described above, the embodiments of the present invention have been described according to the examples. However, it is needless to say that the present invention is not limited to such examples, and can be variously implemented without departing from the gist of the present invention.
[Brief description of the drawings]
FIG. 1 is a process flowchart of a pressure flotation device of an embodiment.
FIG. 2 is an explanatory diagram of a cross-sectional structure of the pressure flotation device of the embodiment.
FIG. 3 is a side view of the pressure flotation device of the embodiment.
[Explanation of symbols]
Reference Signs List 10 pressure flotation device 20 flotation / separation device 21 flotation / separation tank 22 treatment water tank 23 feed well 31 circulating water suction pipe 31a cheese (gas supply means)
31b Needle valve (gas supply means)
32 Circulating water discharge pipe 50 Ozone mixing pump 60 Ozone generator 70 Line mixer 80 Raw water tank

Claims (2)

The pressurized gas-water mixed fluid is supplied to the flotation tank into which the raw water has been introduced to generate fine bubbles derived from the gas-water mixed fluid, and the suspended matter contained in the raw water accompanies the fine bubbles. In a pressure flotation device that separates solid and liquid by floating,
A feed well erected at the center of the bottom of the flotation tank and closed at the lower end,
A baffle (27a) erected at the bottom between the raw water supply nozzle that opens to a side surface of the flotation tank and jets the raw water into the flotation tank and the feed well;
A baffle (27b) erected at the bottom between the feed nozzle and the take-out nozzle, which is erected through the bottom of the flotation tank and drains water in the middle layer of the flotation tank from an opening at the upper end; When,
A circulating pump in which the suction side is connected to the flotation tank outside the feed well and the delivery side is connected to the flotation tank inside the feed well;
Gas supply means for supplying gas to the suction side of the circulation pump,
A pressurized flotation device, comprising: a line mixer interposed in a delivery pipe from the delivery side of the circulation pump to the flotation tank. The pressure flotation device according to claim 1,
A pressure flotation device, wherein ozone generated by an ozone generator is supplied from the gas supply means.

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