JPH0688019B2 - Pressure levitation separator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention utilizes fine air bubbles to float and separate solid particles, which are suspended matter contained in water to be treated, to separate solid and liquid. The present invention relates to a pressure floating separation device.

(Prior Art) In pressure-floating separation, air is dissolved in the water to be treated by pressurizing the water to be treated in which solids, which are suspended solids, are contained as particles, and the pressurized water to be treated is constantly removed. When the pressure is returned to the pressure, the air dissolved in the water to be treated is released as fine bubbles, and thus the fine bubbles are attached to the particles in the water to be treated and floated to separate the solid-liquid.

The pressure floating separation method according to the prior art includes a total pressure method that pressurizes all the water to be treated, a partial pressurization method that pressurizes a part of the water to be treated, and a part of the treated water that has undergone solid-liquid separation. A method of pressurizing circulating water to supply the water to be treated under pressure is known.

FIG. 5 is a specific example of the circulating water pressurization method of the prior art. In the levitation separation, raw water to be treated is supplied into the liquid in the levitation separation tank to perform levitation separation in the liquid.

Reference numeral 1 is a floating tank, and 2 is a treated water discharge pipe, which is installed in the floating tank 1. A water collecting pipe 3 is installed near the bottom of the levitation tank 1 and is for discharging the treated water that has been solid-liquid separated in the levitation tank 1. Reference numeral 4 denotes a treated water tank which accommodates a water level pipe 5 connected to the water collection pipe 3 therein.
The height of the upper surface determines the water level in the floating tank 1.

Reference numeral 6 is a treated raw water tank, 7 is a mixer, and 8 is a pressure tank. The treated raw water tank 6 and the mixer 7 are connected via a pump 9, and the pressure tank 8 is treated via the treated water tank 4 and a pump 10. It is also connected to the mixer 7. or,
The mixer 7 is connected to the treated water discharge pipe 2. Reference numeral 11 is an air inlet for taking air into the pressure tank 8.

Reference numeral 12 denotes a skim rake for scraping up floating objects accumulated on the liquid surface of the floating tank 1, which is connected to a drive shaft of a motor 13 and is rotatably installed. Reference numeral 14 denotes a floating material discharge port provided in the upper portion of the floating tank 1, and reference numeral 15 denotes a precipitate rake for scraping up the precipitate deposited in the floating tank 1.

In the separation device configured as described above, the water to be treated in the treated raw water tank 6 is supplied to the mixer 7 by the pump 9. A part of the separated treated water is supplied to the pressure tank 8 by the pump 10, and is pressurized together with the air supplied from the air inlet 11 in the pressure tank 8 and supplied to the mixer 7. The treated raw water supplied to the mixer 7 is mixed with pressurized treated water and sent to the treated water discharge pipe 2 in a pressurized state.

The treated water supplied from the treated water discharge pipe 2 into the levitation tank 1 under pressure returns to the normal pressure by being released into the liquid at the normal pressure. At this time, the treated water dissolves in the treated water. The air that has formed is released as fine bubbles and floats along with particles in the water to be treated.

The floating material floating on the liquid surface of the floating tank is scraped up by the skim rake 12 and taken out from the floating material discharge port 14.
The treated water that has undergone solid-liquid separation is sent to the treated water tank 4, part of which is discharged, and part of which is pressurized as described above and supplied to the flotation tank 1 again for separation treatment.

In the separation method according to the related art shown in FIG. 5 and the other related art, since the treated water and the pressurized water are supplied into the liquid in the flotation tank so as to be floated and separated, the treated water is separated from the flotation tank. A convection phenomenon occurs inside the water, and therefore the water to be treated supplied into the flotation tank was agitated by the convection phenomenon. As described above, in the levitation separation, the particles are attached to the fine bubbles and the solids are separated by levitation, so if the water to be treated is agitated in the levitation tank, the particles once become the bottom of the levitation tank. As it floats after reaching near, it takes a long time for all the particles to finish floating. Therefore, the only way to increase the separation efficiency of the water to be treated is to make the flotation tank larger.

In the conventional technology, when the amount of water to be treated to be separated is large, it is necessary to provide a large-scale floating tank, and there is a problem that investment efficiency of equipment deteriorates.

(Problems to be Solved by the Invention) The present invention, by supplying the water to be treated above the liquid surface of the flotation tank, prevents the occurrence of convection phenomenon due to the water to be treated in the flotation tank and significantly improves the treatment performance. An object of the present invention is to provide a pressure floating separation device.

(Means for Solving the Problems) Means for solving the problems in the present invention include a cylindrical levitation tank 20 for containing water containing suspended matter, and the levitation tank 20.
A cylindrical mixing chamber 21 arranged in the central portion of the mixing chamber 21 for mixing the suspended matter-containing water and the pressurized water, and the floating matter-containing water provided at the bottom of the mixing chamber 21 and the pressurized water to be mixed therewith into the mixing chamber 21. Treated raw water supply port 22 and pressurized water supply port 23 for taking in, and radially extending in the levitation tank 20 with respect to the axis of the levitation tank 20 and arranged at a position higher than a predetermined height of the suspended matter-containing water. In addition, in order to scrape up the floating material floating on the surface of the water in the floating tank 20, a distribution spray tube 40 that is in communication with the mixing chamber 21 and has a spray port 41 formed along the length thereof. It has a suction cup 52 extending radially with respect to the axis of the levitation tank 20 and for sucking the floated matter scraped up and collected, and is directed toward the suction cup 52 so as to gather the floated matter against the suction cup 52. Slanted rake 51, the distribution pipe 40 and the skimley A reverse cup-shaped rotary cylinder 38, in which a skim rake 51 is provided so that the mounting angle of the brake 51 is directed rearward in the rotation direction of the distribution and dispersion pipe 40, and the rotary tank 38 is mounted so as to rotate around the shaft of the floating tank 20, and the rotary cylinder 38. A rotation drive device for rotating the water, a drain pipe 58 provided in the floating tank 20 for collecting treated water, and a gauge pipe 57 for maintaining the water level in the floating tank 20 at a predetermined height. And is provided.

(Operation) Treated raw water and pressurized water supplied to the bottom of the mixing chamber 21 are mixed chambers.
Although mixed in 21, the inside of the mixing chamber 21 is at atmospheric pressure, and bubbles are gradually flowed upward while precipitating bubbles therein. The deposited bubbles adhere to the particles, which are floating substances, contained in the water to be treated and are supplied from above the mixing chamber 21 onto the liquid surface of the levitation tank 20.

Therefore, since particles having a smaller specific gravity due to the adhesion of bubbles float on the liquid surface of the levitation tank 20, the particles separated by levitation are scraped up by the skim rake 51 to the suction cup 52 and sucked by the float discharge pump 59. Will be eliminated.

Further, since the water to be treated flowing out from the mixing chamber 21 is supplied to the liquid surface of the levitation tank 20 by the distribution and dispersion pipe 40,
The convection phenomenon in the floating tank 20 due to the supplied water to be treated does not occur. Therefore, the processing residence time in the flotation tank 20 can be shortened, so that the processing amount per unit volume of the flotation tank 20 can be significantly increased.

(Embodiment) FIG. 1 is a vertical cross-sectional view of the entire apparatus of the present invention assembled, and FIG. 2 is a plan view of the same.

This embodiment is a treatment apparatus using a circulating water pressurization method. In these figures, the flotation tank 20 is formed in a plane circular shape, a cylindrical mixing chamber 21 is provided at the center of the tank, and a treated raw water supply port 22 and a pressurized water supply port are provided at the bottom of the mixing chamber 21.
23 are provided. The treated raw water supply port 22 is a treated raw water tank 24.
The pressurized water supply port 23 is connected to the pressurized tank 25.

The treated raw water tank 24 is connected to the treated raw water supply port 22 via a pump 26, a flow rate adjusting valve 27, and a flow meter 28, so that the treated raw water stored in the treated raw water tank 24 and the pressure tank 25. The pressurized water stored in and the bottom of the mixing chamber 21 are supplied.

In the pressure tank 25, treated water taken out of a treated water tank 29 provided outside the floating tank 20 is stored together with air under pressure by a pressurized water pump 30. Further, a pressure reducing valve 31, a flow meter 32, and a flow rate adjusting valve 33 are provided in a passage between the pressurized water supply port 23 and the pressurized tank 25. Further, a medicine tank 34 storing a medicine such as a coagulant is connected between the pressure reducing valve 31 and the flow meter 32 via a medicine supply pump 35. 36 is a medicine stirring means of the medicine tank 34. An air inlet 37 is provided between the treated water tank 29 and the pressurized water pump 30 so that the flow rate of the treated water can be adjusted.

At the upper end of the mixing chamber 21, there is rotatably provided a cup-shaped rotary cylinder 38 with its bottom portion facing upward. An outlet 39 is formed in the rotary cylinder 38, and a horizontal distribution spray pipe 40 is fixed in a state of communicating with the outlet 39, and the distribution spray pipe 40 is connected to the pipe. Forming a spray port 41 that opens along and flows out from the outlet 39 (overflow)
The treated water (mixed raw treated water and pressurized water) is distributed and supplied from above to the liquid surface in the floating tank 20 through the distribution and dispersion pipe 40.

Further, the rotary cylinder 38 has a drive shaft 43 which is vertically projectable from a frame 42 which covers the upper surface of the floating tank 20 and which is rotatable.
Is fixed, and a drive gear 45 of a rotary drive device 44 provided on the frame 41 and a driven gear 46 provided on the upper end of the drive shaft 43 are linked by a chain 47.

Reference numeral 48 is a seal structure mounted between the mixing chamber 21 and the rotary cylinder 38, and 49 is a bearing mounted between the frame 42 and the drive shaft 43.

Further, inside the flotation tank 20, a skim rake 51 for scraping up the floated material 50 floated and separated on the liquid surface of the flotation tank with the rotation of the rotary cylinder 39, and the floated material 50 scraped up by the skim lake 51. Is provided with a suction cup 52.

The ski rake 51 is a mounting rod 51 fixed to the rotary cylinder 38.
The floating object 5 is provided on the suction cup 52.
It is inclined toward the suction cup 52 so as to collect 0s.

In addition, a sediment rake 54 for collecting the sediment deposited on the bottom of the floating tank 20 at the sediment removal port 53 is provided. The precipitate rake 54 is provided in the radial direction around the mixing chamber 21 and is connected to the rotary cylinder 39 so as to rotate as the rotary cylinder 39 rotates.

Then, a water collecting pipe 56 is provided on the lower surface of the partition plate 55 provided near the bottom of the floating tank 20, and a gauge pipe connected to the water collecting pipe 56.
By raising 57 to the treated water tank 29 and opening it, the height of the water surface of the floating tank 20 is made to match the rising dimension of the gauge pipe 57. 58 is the treated water tank
A drainage pipe provided in 29, 59 is a floating material discharge pump installed in the frame 41, and the floating material discharge pump 59 and the suction cup 49 are connected via a suction pipe 60 and a universal joint 61. Reference numeral 62 denotes a discharge pipe connected to the precipitate removal port 53, which is opened / closed by a valve 63 and is normally closed.

As shown in FIG. 2, the distribution pipe 40 is provided along the radial direction of the flotation tank 20 and is driven to rotate clockwise in the drawing by a drive unit 44, and a skim rake 51 and suction are provided in the rear of the rotation direction. A cup 52 is provided. Further, the skim rake 51 is inclined forward in the rotational direction as the skim rake 51 is separated from the suction cup 52 so as to collect the floating object 50 toward the suction cup 52.

In the pressure levitation separation device configured as described above, the treated water stored in the treated water tank 29 is a pressurized water pump together with air in a weight ratio of 1/10 to 1/50 with respect to particles contained in the treated raw water. It is pressurized by 30 to, for example, ² to 4 kg / cm ² , and is supplied to the pressure tank 25. Therefore, the pressurized tank 25 stores the treated water in which a large amount of air is dissolved.

In the embodiment, air is mixed into the suction side of the pressurized water pump 30 and is pressurized together with the treated water so that the means for compressing the air is omitted, but after the treated water and the air are each independently compressed. It can also be supplied to the pressure tank 25.

The flow rate of the treated water stored in the pressurizing tank 25 is controlled by the flow rate adjusting valve 33, and the processed water is mixed with the medicine delivered from the medicine tank 34 through the medicine supply pump 35 through the pressure reducing valve 31 and the pressurized water supply port 23. Supplied at the bottom of chamber 21. or,
The treated raw water stored in the treated raw water tank 24 is pump 26,
Flow rate is controlled by the flow rate adjustment valve 27 and the raw water supply port for treatment 22
Is mixed with the pressurized water supplied from the pressurized water supply port 23 (becomes water to be treated) and gradually rises in the mixing chamber 21.

Since the mixing chamber 21 is maintained at atmospheric pressure, the air dissolved in the high-pressure treated water supplied from the pressurized water supply port 23 is deposited as fine bubbles and is contained in the water to be treated. Attach to particles.

Then, the water to be treated reaching the upper end of the mixing chamber 21 flows out together with the particles to which the bubbles are attached from the outlet 39 formed in the rotary cylinder 38, and the distribution spray pipe rotating in the floating tank 20 in the clockwise direction. It is uniformly supplied to the liquid surface in the flotation tank 20 from the spraying ports 41 of 40.

The particles contained in the water to be treated supplied to the liquid surface of the flotation tank 20 are quickly floated and separated because the specific gravity is corrected to be reduced due to the adhesion of bubbles, and the distribution spray pipe is used.
Skim rake 51 rotating with 40 suction cup
It is scraped up to 52 and sucked away by the floating material discharge pump 59.

In addition, a precipitate having a larger specific gravity than water settles at the bottom of the flotation tank 20, and the precipitate rake 54 scrapes it to remove the precipitate.
Scraped to 53. Therefore, only water (floating water) that does not contain flotation and sediment flows into the water collection pipe 56, and the gauge pipe
It is supplied to the treated water tank 29 via 57. A part of the treated water supplied to the treated water tank 29 is a pressurized water pump as described above.
Although it is circulated and supplied to the levitation tank 20 together with air under the pressure action of 30, the remaining treated water is discharged from the drain pipe 58.

In the pressure levitation separation apparatus of the embodiment, the mixing chamber 21 in which the solid particles contained in the water to be treated and the bubbles are combined is substantially independent of the levitation tank 20, and the treatment target flowing out of the mixing chamber 21 is treated. Water is supplied to the liquid surface of the floating tank 20 from above. Therefore, in the flotation tank 20, only subsidence due to the supply of the water to be treated was observed, stirring was not performed as in the conventional case, and the subsidence of bubbles was extremely shallow. Therefore, the required water depth of the flotation tank 20 only needs to be suitable for the subsidence, and since the stirring is not performed, the required area is also minimal.

As an example, in a flotation tank with a surface area of 1 m ² , when the pressurized treated water of 2 m ^{3 /} h is circulated and the treated water of 5 m ^{3 /} h is supplied to the mixing chamber, the subsidence depth of bubbles is 0.3 m at maximum. there were. Therefore, even if the safety factor is doubled, it is sufficient to set the effective water depth of the floating tank to a maximum of 0.6 m.

The required water depth of 0.6m is calculated by the following formula.

For this reason, the residence time required for processing is Becomes

In other words, it is possible to process a total amount of 7 m ³ per hour using a floating tank having a surface area of 1 m ² , effective water depth of 0.6 m, and residence time of 5 minutes. For this reason, if an attempt is made to obtain the same processing capacity, the effective water depth of the flotation tank can be made 1/4 to 1/5 the depth of the conventional example. It can be miniaturized.

In the embodiment, the skim rake 51 and the suction cup 52 are arranged at an angle of about 270 ° behind the distribution / dispersion pipe 40. However, this angle is increased to about 315 to 340 ° to disperse the water to be treated. It is also possible to increase the processing capacity by increasing the time lag from the removal of floating objects.

Further, in the embodiment, a part of the treated water is pressurized together with air and circulated and supplied to the floating tank to prevent wear of the pressurizing pump.

FIGS. 3 and 4 show another embodiment, FIG. 3 is a vertical sectional view of the entire apparatus assembled, and FIG. 4 is a plan view of the same.

This embodiment also uses the circulating water pressurization method, and the floating tank has a rectangular shape. A mixing chamber 21 is provided on the side surface of the levitation tank 20 formed in a flat rectangular shape, and the water to be treated flowing out of the mixing chamber 21 is supplied to the liquid surface of the levitation tank 20 from one end using a guide plate 70,
A treated water outlet 71 and a floating material outlet 72 are provided at the end opposite to the mixing chamber 21. A second skim rake 74, which is composed of an endless belt and is provided on a rotatable conveyer 73, is provided above the levitation tank 20 so that the levitated matter floating on the water surface is levitated by the second skim rake 74. The material is discharged to the discharge port 72.

Since the other parts have substantially the same configuration as the above-mentioned embodiment, the parts having the same functions are designated by the same reference numerals and the description thereof is omitted.

(Effect of the Invention) In the present invention, since the water to be treated flowing out of the mixing chamber is supplied to the liquid surface of the flotation tank, stirring in the flotation tank is not performed by the supplied water to be treated. Therefore, the flotation separation efficiency in the flotation tank is improved, the required surface area and water depth of the flotation tank can be reduced, and the treatment retention time can be shortened, so the amount of treated water per unit volume of the flotation tank can be greatly increased. Is something that can be done.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of the whole assembly of the device of the present invention, FIG. 2 is a plan view of FIG. 1, FIG. 3 is a vertical sectional view of the whole device according to another embodiment, and FIG. FIG. 5 is an explanatory view of an apparatus according to the prior art. 20 …… Floating tank, 21 …… Mixing chamber, 22 …… Processed raw water supply port 23 …… Pressurized water supply port, 24 …… Processed raw water tank, 25 …… Pressurized tank 26 …… Pump, 27 …… Flow control valve , 28 …… Flowmeter 29 …… Treated water tank, 30 …… Pressurized water pump, 31 …… Pressure reducing valve 32 …… Flowmeter, 33 …… Flow control valve, 34 …… Drug tank 35 …… Drug supply pump, 36… … Mechanical agitator, 37 …… Air inlet 38 …… Rotary cylinder, 39 …… Outlet, 40 …… Distribution spray pipe 41 …… Spray port, 42 …… Frame, 43 …… Drive shaft 44 …… Rotation drive Device, 45 …… Drive gear, 46 …… Driven gear 47 …… Chain, 48 …… Seal structure, 49 …… Bearing 50 …… Float, 51 …… Skim rake, 52 …… Suction cup 53 …… Sediment removal Mouth, 54 ... Sediment rake, 55 ... Partition plate 56 ... Water collection pipe, 57 ... Gauge pipe, 58 ... Drain pipe 59 ... Float discharge pump, 60 ... Suction pipe, 61 ... Universal joint 63 …… B Lube, 62 ... Discharge pipe, 70 ... Guide plate 71 ... Treated water outlet, 72 ... Float discharge port, 73 ... Conveyor 74 ... Second skim rake

Claims (2)

[Claims] 1. A cylindrical flotation tank (20) for accommodating water containing suspended matter, and a cylindrical mixture disposed in the center of the flotation tank (20) for mixing suspended water and pressurized water. A chamber (21), a treated raw water supply port (22) and a pressurized water supply port which are provided at the bottom of the mixing chamber (21) and take in floating material-containing water and pressurized water to be mixed with the same into the mixing chamber (21) (23) and the mixing chamber (21), which is radially extended in the floating tank (20) with respect to the axis of the floating tank (20) and is arranged at a position higher than a predetermined height of the water containing suspended solids. ) And a distribution spray pipe (40) having a spray port (41) formed along the length thereof, and for collecting floating substances floating on the surface of the water in the floating tank (20). Has a suction cup (52) extending radially with respect to the axis of the levitation tank (20) and for sucking up the collected floating objects. A skim rake (51) that is inclined toward the suction cup (52) so as to collect floating substances together with the suction cup (52), and the mounting angles of the distribution spray pipe (40) and the skim rake (51). A reverse cup-shaped rotary cylinder (38) provided with a skim rake (51) provided rearward in the rotation direction of the distribution spray pipe (40) so as to rotate around the shaft of the floating tank (20) at the same time; A rotation drive device for rotating the tube (38), a drain pipe (58) provided in the levitation tank (20) for collecting treated water, and a predetermined water level in the levitation tank (20). A pressure levitation separation device comprising: a gauge tube (57) for maintaining the height. 2. The mounting angle between the distribution pipe (40) and the skim rake (51) is set to the rear of the direction of rotation of the distribution pipe (40).
The pressure levitation separation device according to claim 1, wherein the skim rake (51) is arranged at an angle of 270 ° or more.