JP2002119957A - Pressure floatation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure floatation apparatus in which the inner structure of a tank body is simple, small-sized and inexpensive and by which floatation separation treatment can be performed efficiently and at high speed. SOLUTION: A mixed water of an original water and a pressurized water is made to flow into a feed well 30 in the tangential direction from an influent conduit 32 and is elevated in the feed well 30 as a spiral flow and is made to flow out on a truncated cone-like guide plate 35 from the top end of the feed well 30 and is fed into a floatation tank as a uniform, gentle and radial flow. The treated water separated from scum makes a detour around the bottom end of an outside treated water separating cylinder 41 and is elevated between the outside treated water separating cylinder 41 and an inside treated water separating cylinder 40 and is overflowed into the inside treated water separating cylinder 40 from the top end of the inside treated water separating cylinder 40 and is drained through a discharge hole 42 and a discharge pipe 43.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for subjecting water containing suspended substances (SS) to pressurized flotation treatment from water containing the suspended solid (SS). The present invention relates to a pressure flotation device capable of reducing the size of equipment and improving processing efficiency.

[0002]

2. Description of the Related Art As one method of treating water containing SS,
Pressurized water is mixed with raw water and supplied to a floating tank, and SS in raw water is adsorbed by micro air in the tank and floated on the surface of water, and this is lifted and discharged by a scum lake (schema). is there. There are square and round types of floating tanks used in this pressurized flotation treatment method. In many cases, round types are adopted from the viewpoint of reducing the installation area and improving the efficiency of floating mud removal. ing.

In a round pressurized levitation apparatus, mixed water of raw water and pressurized water (hereinafter, sometimes simply referred to as "mixed water") is supplied from a bottom of the levitation tank through a feed well provided inside the tank. Supplied to the top. The feed well includes an open type having an open upper portion and a feed well having an upper portion connected to a distributor. Among them, the one with the upper part connected to the distributor has the advantage that the mixed water is evenly distributed in the tank by the rotating distributor, but the equipment configuration and maintenance are complicated, so the equipment configuration and maintenance In terms of surface, an open type with an open top is more advantageous.

In order to stably and surely obtain treated water having good water quality by the pressurized levitation treatment method, SS in raw water is efficiently adsorbed to micro-air generated from pressurized water, and good buoyancy is required. It is an important condition that the surface floats effectively and stably floats on the water surface without subsidence again after the surface rises.

However, in a pressurized flotation device provided with an open type feed well, mixed water flowing into the flotation tank from the upper opening of the feed well is blown up onto the water surface, causing turbulence on the water surface.

[0006] Further, after the mixed water is jetted from the upper opening of the feed well, it immediately comes into contact with air, and at that time, undergoes a sudden change in pressure. Due to such a turbulent flow and a rapid pressure change, the micro air is dissociated from the combined body of the SS and the micro air contained in the mixed water, whereby the SS sinks and the quality of the treated water deteriorates.

[0007] Therefore, in a pressure flotation device provided with an open type feed well, in order to prevent the deterioration of the treated water quality due to the blowing of the mixed water and to obtain the treated water of good water quality. Has a water area load of 6-8 m ³ /
m had to be suppressed to about ² · hr. However, such restriction of the water area load is not preferable in terms of the installation area of the floating tank and the processing efficiency.

In order to solve these problems, in a pressurized flotation device provided with an open type feed well, the water area load is increased to reduce the size of the equipment and improve the processing efficiency (high-speed flotation). Japanese Patent Application Laid-Open No.
Japanese Patent No. 272456 discloses a tank body having an annular peripheral wall, a distributor extending radially from a central portion of the tank body, and capable of rotating around the central portion in the tank body. A pressurizing device comprising: a turning drive device of a distributor; means for supplying mixed water of raw water and pressurized water into the distributor; and a mixed water outlet provided in the distributor and opening toward the downstream side in the rotational direction. A levitation device is described.

In such a pressurized flotation device, since the water flows out from the distributor toward the downstream side in the distributor turning direction, the flow of the water is not easily disturbed. For this reason, the suspended substance is prevented from being finely divided and bubbles are prevented from being detached, so that an efficient flotation separation process is performed.

FIG. 3A is a longitudinal sectional view of the pressure flotation device described in the publication, and FIG. 3B is a plan view thereof.

The tank body 1 having an annular peripheral wall is formed in a conical shape in which the bottom is lowered toward the center, and the pit 1 is formed in the center.
a is provided. Raw water supply pipe 2 from this pit 1a
Is started up halfway in the tank body 1. A pressurized water supply device (not shown) is connected to the raw water supply pipe via a pressurized water valve 3. The pit 1a has a drainage valve 1b
Is connected.

A water collecting pipe 4 is provided below the tank body 1. The water collecting pipe 4 is a donut-shaped tubular member that circulates along the peripheral wall of the tank body 1 and is provided with a hole-shaped water collecting port (not shown) at a predetermined interval in the longitudinal direction. Reference numeral 4a denotes a water collection drain pipe connected to the water collection pipe 4.

A connecting portion 10 of the distributor 5 is fitted on the upper end of the raw water supply pipe 2. Four distributors 5 extend in the radial direction of the tank body 1, and the distributors 5 are assembled (connected) at the center of the tank body 1. The cylindrical connecting portion 10 protrudes downward from the gathering portion of the distributor 5.

The distributor 5 is turned inside the tank 1 by a motor 8. An opening 6 for water outflow is provided in the distributor 5 so as to face the wake in the turning direction.

A skimmer 7 for scraping floating scum is provided near the water surface of the tank body 1. The gap 7 is also rotated (turned) integrally with the distributor 5 by the motor 8. A scum outflow portion 9 a and a trough 9 are provided on a part of the peripheral wall of the tank body 1.

In such a pressurized levitation apparatus, since water flows out from the distributor 5 toward the downstream side in the swirling direction of the distributor 5, the effluent is less likely to be turbulent, and the levitation separation processing is performed efficiently and at high speed. Is performed.

However, in the pressure flotation device shown in FIG. 3, since the water collecting pipe 4 is provided in a donut shape, the internal structure of the flotation tank is complicated and large. Further, the donut-shaped water collecting pipe 4 has a disadvantage that it is difficult to uniformly collect the treated water.

Further, since the distributor 5 is used, the internal structure of the floating tank is more complicated.

Therefore, a pressurized levitation apparatus with a simpler structure and capable of high-speed levitation separation processing has been studied.
No. 76437 proposes a pressure flotation device.

The pressurized levitation apparatus disclosed in Japanese Patent Application Laid-Open No. 2000-176437 discloses a levitation tank and a levitation tank provided in the levitation tank.
A pressurized flotation device comprising a feed well having an open upper portion, wherein raw water containing dissolved gas is supplied to a lower portion of the feed well, rises in the feed well, and flows through the upper opening into the floating tank. A shielding plate is provided between an upper opening of the feed well and the surface of the floating tank.

In such a pressurized flotation device, since the shielding plate is provided above the upper opening of the feed well,
The mixed water that has flowed up the feed well and flowed into the floating tank from the opening does not directly blow up to the water surface, and the combined body of SS and micro air goes around the lower surface of the shielding plate and has a uniform and gentle flow. To reach the surface of the water
Dissociation between the SS and the micro air is prevented. For this reason,
Even if the water area load is increased, the treatment can be performed stably without lowering the quality of the treated water due to dissociation of the SS and the micro air.

FIG. 4 is a sectional view showing a pressure flotation device disclosed in Japanese Patent Application Laid-Open No. 2000-176437.

In this pressurized levitation apparatus, an inner tank 12 is provided along the inner periphery of a tank body 11 of a floating tank.
Between the treated water can be raised. This tank 11
A feed well 20 is provided upright, a raw water inflow pipe 13 is connected to the feed well 20, and a pressurized water inflow pipe 14 is connected to the raw water inflow pipe 13.

The raw water and the pressurized water flow from the inflow pipes 13 and 14 through the feed well 20 into the floating tank, where solid-liquid separation is performed. The treated water flows around the lower end of the inner tank 12 and
It rises between 2 and the tank body 11 and is discharged from the treated water trough 15. On the other hand, the floating scum is raked by the scum rake 16, dropped into a scum box (not shown), and discharged from a discharge port (not shown). Reference numeral 17 denotes a motor for driving the scum rake 6, and 17a denotes a bearing.

Above the upper opening 20A of the feed well 20, a shielding plate 21 as a short-circuit preventing and rectifying mechanism for mixed water is provided.
Is provided. By providing the shielding plate 21, the mixed water flowing out of the feed well 20 does not directly blow up onto the water surface L, but the mixed water spreads gently into the tank, so that the floating separation process can be efficiently performed at high speed. Done.

[0026]

However, in Japanese Patent Application Laid-Open No. 2000-176437, the inner tank 12 is provided along the inner periphery of the tank body 11, so that the size of the tank body 11 is increased. Trough 1 projecting outward from tank body 11
No. 5 was adopted, and the pressure flotation device was enlarged.

An object of the present invention is to provide a pressure flotation apparatus which can perform high-speed flotation separation processing with a simpler and smaller structure.

[0028]

SUMMARY OF THE INVENTION A pressure flotation apparatus according to the present invention comprises a flotation tank, a feed well provided in the flotation tank and having an open top, and a treated water provided in a lower part of the flotation tank. A pressurized flotation device having a discharge port, wherein raw water containing dissolved gas is supplied to a lower portion of the feed well, rises in the feed well, and is introduced into the levitating tank from an upper opening. In the pressure flotation device, a guide plate is connected to the upper part of the feed well so that raw water flowing out from the upper part of the feed well flows down on the plate surface, and an inner treated water separation cylinder surrounding the outer periphery of the feed well. ,
An outer treated water separation tube surrounding the outer periphery of the inner treated water separation tube, and the treated water discharge port is provided on the inner treated water separation tube or inside thereof, and the floating tank The treated water inside flows into the space between the outside treated water separation tube and the inside treated water separation tube from the lower end of the outside treated water separation tube, and from the upper end of the inside treated water separation tube to the inside of the inside treated water separation tube. It is characterized by overflowing and flowing out of the treated water discharge port.

In such a pressurized flotation device, the mixed water flowing out from the upper portion of the feed well flows along the upper surface of the guide plate and is supplied to the surface of the flotation tank. The mixed water is introduced into the floating tank without being separated. Then, the floating separation processing is efficiently performed in the floating tank.

The treated water from which the SS has been separated descends in the floating tank, goes around the lower end of the outer treated water separation cylinder, rises between the outer treated water separation cylinder and the inner treated water separation cylinder, and rises inside the treated water separation cylinder. The water overflows from the upper end of the treated water separation tube into the inner treated water separation tube and flows out from the treated water discharge port.

In this pressurized levitation apparatus, an inner tub or a doughnut-shaped water collecting pipe is not required in the tank body, no distributor is used, and the configuration of the pressurized levitation apparatus is simple. A small body is enough.

[0032]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 (a) is a longitudinal sectional view showing an embodiment of the pressure flotation device of the present invention, and FIG. 1 (b) is FIG. 1 (a).
1C is a perspective view showing the upper part of the feed well and the guide plate, FIG. 1C is a sectional view taken along the line CC of FIG. 1A, and FIG. 2 is a sectional view taken along the line II-II of FIG. .

A feed well 30 is provided upright from the center of the bottom of a tank 31 having a cylindrical peripheral wall. A raw water inflow pipe 32 is connected to a lower end of the feed well 30, and a pressurized water valve is connected to the raw water inflow pipe 32. Pressurized water inlet pipe 3 having
3 are connected.

The raw water inflow pipe 32 is tangentially connected to the feed well 30 as shown in FIG.
By arranging the raw water inflow pipe 32 tangentially to the feed well in this way, the mixed water of the raw water and the pressurized water flowing into the lower part of the feed well 30 rises while turning inside the feed well 30. This prevents the mixed water from short-circuiting to the upper portion of the feed well 30.

The upper opening 30A of the feed well 30 is
It protrudes above the water surface in the tank body 31. A guide plate 35 having a truncated conical shape (a helmet shape) that slopes downward from the upper end of the feed well 30 toward the outside is provided. The downward inclination angle of the guide plate 35 is preferably about 10 to 30 °. The inner peripheral end of the guide plate 35 is connected to the upper end of the feed well 30 in a watertight manner. The outer peripheral end of the guide plate 35 protrudes further outward than the outer treated water separation cylinder 41 described later.

A scum box 36 for drainage is provided so as to project inward from a part of the inner peripheral surface of the tank body 11. Reference numeral 37 denotes a discharge port from the scum box 36. A scum lake 38 is provided to guide the scum floating on the water surface in the tank body 31 to the scum box 35. Reference numeral 39 denotes a motor for driving the scum rake 38.

An inner treated water separation tube 40 and an outer treated water separation tube 41 surrounding the feed well 30 are provided in a double cylinder shape. The inner treated water separation cylinder 40 is provided upright from the bottom surface of the tank 31, and the upper end thereof matches the water level in the tank 31. The outer treated water separation tube 41 is arranged on the outer peripheral side of the inner treated water separation tube 40. The lower end of the outer treated water separation cylinder 41 is located higher than the bottom of the tank body 31 by a required distance. The upper end of the outer treated water separation cylinder 41 projects above the water level of the tank 31, but the guide plate 3
It is located lower than 5.

A treated water discharge port 42 is provided below the inner treated water separation cylinder 40, and a treated water discharge pipe 43 is connected to the treated water discharge pipe 43. The treated water outlet 42 may be provided on the bottom surface of the tank 31. The discharge port 42 is provided in the feed well 30 in some cases, and the discharge pipe 4
3 may be configured to penetrate near the center of the bottom surface of the tank body 31.

The mixed water of the raw water and the pressurized water flows from the inflow pipe 32 through the feed well 30 into the floating tank, where solid-liquid separation is performed. As shown in FIG. 2, this mixed water flows in a tangential direction to the feed well 30 and rises in the feed well 30 as a swirling flow. Is done. The mixed water of the raw water and the pressurized water that has risen as a swirling flow in the feed well 30 flows out from the upper end of the feed well 30 onto the guide plate 35, and becomes a uniform and gentle radial flow to form the tank body 3.
1, the SS and the micro air flow into the tank body 31 without being separated. Therefore, the tank body 31
Inside, the floating separation processing is performed efficiently and at high speed.

The scum that has floated in the tank 31 is dropped into the scum box 36 by the scum lake 18 and discharged from the mud outlet 37.

On the other hand, the treated water separated from the scum goes around the lower end of the outer treated water separation cylinder 41, rises between the outer treated water separation cylinder 41 and the inner treated water separation cylinder 40, and is separated from the inner treated water separation cylinder 41. The water overflows from the upper end of the cylinder 40 into the inner treated water separation cylinder 40. Then, the water is discharged from a lower outlet 42 of the inner treated water separation tube 40 through a treated water discharge pipe 43.

The guide plate 35 may be a skirt-like shape having an integral structure, or may be a divided body of a fan-shaped inclined plate.

In the above embodiment, the outer peripheral end of the guide plate 35 is located above the water surface, but the outer peripheral end of the guide plate 35 may be immersed in the water surface as shown in FIG.
In the case of the configuration as shown in FIG. 5, water does not fall from the end of the guide plate 35, and the water transmitted through the guide plate 35 gently merges with the water in the tank body 31. Micro-air is not easily separated from the flock or the flock is broken.

FIG. 6 is a perspective view of an upper portion of a feed well provided with a plurality of radial flow path members as guide plates.

The guide plate (channel material) 35A has a gutter-like shape having a vertical cross section perpendicular to the flow direction or a substantially upward U-shape. The guide plate 35 </ b> A has its base end connected to the upper end of the feed well 30, and is inclined so that the lower end is closer to the distal end in the radial direction. In FIG. 6, four guide plates 35A are provided, but another number may be provided. In addition, in FIG. 6, the cross-sectional shape is an upward U-shape, but may be substantially U-shaped. The guide plate 35A may be tubular.

In the above embodiment, the whole or most of the guide plate is located on the water surface, but the upper end of the feed well is located below the water surface, and the entire guide plate is placed in water. Is also good. In this case, it is preferable that the water flowing upward from the feed well is not blown up from the water surface.

In any form, in the present invention, the flow rate in the feed well is 0.05 to 0.2 m / s.
ec is preferred. Further, the flow velocity on the guide plate is preferably 0.05 to 0.2 m / sec.

[0049]

As described above in detail, according to the pressurized flotation apparatus of the present invention, the mixed water of raw water and pressurized water is gently and evenly supplied to the inside of the tank, and the flotation separation process can be performed efficiently. .

The pressurized levitation apparatus of the present invention does not have a treated water trough protruding outward from the tank body or an inner tank or a doughnut-shaped water collecting pipe along the inner periphery of the tank body, so that the equipment can be downsized. Thus, high-speed flotation processing can be performed. The device of the present invention
The internal structure of the tank body is simple and the cost is low.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a pressure flotation device of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a configuration diagram showing a conventional example.

FIG. 4 is a configuration diagram showing another conventional example.

FIG. 5 is a cross-sectional view of an upper part of a feed well of the pressure flotation apparatus according to the embodiment.

FIG. 6 is a perspective view of an upper portion of a feed well of a pressure flotation device according to another embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 30 feed well 31 tank body 32 raw water inflow pipe 33 pressurized water inflow pipe 35, 35A guide plate 38 scum lake 39 motor 40 inner treated water separator 41 outer treated water separator 42 treated water outlet 43 treated water drain pipe

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akira Kojima 3-7, Nishi-Shinjuku, Shinjuku-ku, Tokyo F-term in Kurita Industries Co., Ltd. 4D037 AB02 BA02 BB04 CA06

Claims (3)

[Claims] 1. A pressurized flotation device comprising a flotation tank, a feed well provided in the flotation tank, the feed well having an open top, and a treated water discharge port provided at a lower part of the flotation tank. A raw water containing a dissolved gas is supplied to a lower part of the feed well and rises in the feed well and is introduced into the floating tank from an upper opening; A guide plate is provided at an upper portion of the feed well for flowing the water in a direction away from the feed well, and an inner treated water separation cylinder surrounding the outer periphery of the feed well; and an outer periphery of the inner treated water separation cylinder. An outer treated water separation cylinder surrounding the treated water discharge port, wherein the treated water discharge port is provided on the inner treated water separation cylinder or inside thereof, and the treated water in the floating tank is provided on the outside of the floating tank. Treated water From the lower end of the release cylinder flows between the outer treated water separating cylinder and the inner treated water separation tube,
A pressurized flotation device characterized by overflowing from the upper end of the inner treated water separation tube to the inside of the inner treated water separation tube and flowing out of the treated water discharge port. 2. The pressure flotation device according to claim 1, wherein the guide plate is connected to an upper end of the feed well and has a truncated conical shape that goes around the entire circumference of the feed well. 3. The pressure flotation device according to claim 1, wherein the guide plate is connected to an upper end portion of the feed well and is composed of a plurality of flow passage members extending radially from the feed well.