JP3414651B2 - Underwater mechanical stirring and aeration equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is installed in a treatment liquid in an aeration tank, submerged in the treatment liquid, and introduces air by a blower provided outside the treatment tank to mix and release the air into the treatment liquid. The present invention relates to a lower suction, upper discharge type submersible mechanical stirring and aerating device (hereinafter, the stirring and aerating device is referred to as an aerator) that stirs a liquid to mix fine air into a treatment liquid in an aeration tank.

[0002]

2. Description of the Related Art When treating a treatment liquid such as sewage with aerobic microorganisms in an aeration tank, it is necessary to mix a large amount of fine air into the aeration tank. Therefore, a machine equipped with an axial flow impeller is required. An underwater aerator is used. This mechanical underwater aerator agitates the treatment liquid in the aeration tank, and air is supplied from outside the aeration tank, and the supplied air mixes into the treatment liquid in the aerator and removes the treatment liquid mixed with air. It is discharged or discharged into the aeration tank.

FIG. 11 shows a conventional lower suction upper discharge type submersible mechanical aerator 1A. An impeller 5 is provided with its rotation axis vertical, and a discharge casing 12 is mounted above the suction casing 6 whose lower portion is an inlet for the processing liquid. A discharge port 21 is provided around the upper portion of the discharge casing 12,
The processing liquid discharged from the impeller 5 is discharged from the discharge port 21 in the radial direction. Then, the compressed air A is introduced through the pipe 9 from a blower (not shown) provided outside the aeration tank, and the wake (A) of the impeller 5 of the discharge casing 12 is introduced.
It is mixed in the processing liquid in 1).

As described above, when the treatment liquid is discharged from the aerator 1A by the impeller 5, a large amount of air is mixed, and after being discharged, it spreads in a plane in the aeration tank in a radial direction and contains air. The treatment liquid having a low density rises by exchanging the position with the upper liquid, so that the treatment liquid in the tank is forcibly stirred.

By this action, air is supplied to every corner in the aeration tank and the aerobic microorganisms are activated. And
Organic substances and suspensions in the treatment liquid are adsorbed and decomposed by the action of aerobic microorganisms.

On the other hand, in the case where non-fine air bubbles (relatively large air bubbles) are mixed in the aerator in the aeration tank, they are mixed in the processing liquid horizontally discharged from the discharge casing. The relatively large bubbles are separated from the processing liquid immediately after being discharged from the outlet of the discharge casing, and the separated position (a position radially outward from the outlet of the aerator discharge casing and separated from the outlet in the radial direction). Ascend while moving in the area around (position).

[0007] In this aerator, when the diameter of the outlet of the upper discharge casing is smaller than the diameter of the aeration tank, the separately rising air is supplied only locally to the inside of the tank. In other words, an area where the air is not supplied is created in the aeration tank. Originally, it is preferable that the air mixed in the aeration tank uniformly spread to the aerobic microorganisms present in the treatment liquid in the tank. Therefore, if the supply range of the discharged air is limited and there is a region where the air is not supplied in the aeration tank, the aeration efficiency is lowered from the viewpoint of mixing in the aeration tank evenly. It will be.

In order to improve such a problem, for example, in the technique disclosed in Japanese Utility Model Publication No. 7-17440, the outlet flow of the aerator is directed downward from the horizontal direction, and the treatment liquid is directed outward from the center of the aerator. It is configured so that it can be delivered and the discharge speed is increased.

According to the technique disclosed in Japanese Utility Model Publication No. 7-17440, even when the bubbles rise immediately after being discharged from the discharge casing, the distance that the bubbles reach the surface of the treatment liquid in the aeration tank becomes long, and The contact time with the treatment liquid also becomes longer, and the amount of air dissolved in the treatment liquid also increases. in this way,
By directing the flow at the outlet of the discharge casing downward, the bubble diffusion performance can be improved, and as a result, the air content inside the aeration tank increases.

As described above, Japanese Utility Model Publication No. 7-17440 discloses a useful technique.

However, there are various shapes of aeration tanks for treating the treatment liquid, and there are various shapes and sizes of mechanical aerators used in the aeration tanks.

When using a mechanical submersible aerator having a relatively small outer diameter of the discharge casing with respect to the size of the aeration tank, the flow of the outlet of the submersible aerator is directed downward from horizontal and the treatment liquid is It is preferable to increase the discharge speed so that the discharge reaches the outside of the center of the aerator.

On the other hand, on the contrary, when a mechanical underwater aerator whose discharge casing outer diameter is relatively large relative to the size of the aeration tank is used, the flow at the outlet of the underwater aerator remains as it is. It is preferable that the structure is such that it is not sucked in through the inlet, because the rate of air inclusion in the processing liquid is increased.

That is, it is desired that the same mechanical aerator can be adapted to various usage states of the submersible aerator in aeration tanks of various shapes and sizes.
However, in the prior art, it was not possible to cope with the various usage states described above with the same mechanical aerator.

[0015]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above-mentioned problems of the prior art, and can be easily adapted to various usage conditions in aeration tanks having different shapes and sizes. The purpose of the present invention is to provide a submersible mechanical stirring aerator.

[0016]

The submersible mechanical stirring and aeration apparatus of the present invention is installed by submerging it in a treatment liquid in an aeration tank,
Lower suction and top discharge type underwater mechanical stirring aeration that guides air from the outside of the aeration tank to mix and release it into the processing liquid and agitate the processing liquid in the tank to mix fine air into the processing liquid inside the aeration tank. In the apparatus, a casing cover is provided over the entire circumference of the end of the discharge port provided around the upper part of the discharge casing of the stirring and aeration device, and the casing cover guides the flow of the discharged processing liquid outward in the radial direction. Each of the divided pieces (which means the divided casing parts) is detachably engaged with the upper portion of the discharge casing.

Here, as a means for introducing air into the aeration tank, for example, a blower can be used.

Further, it is preferable to use bolts for detachably attaching the divided pieces of the casing cover to the discharge casing.

In carrying out the submersible mechanical stirring and aeration apparatus of the present invention, the casing cover has its upper wall surface inclined downward in the radial direction, so that the treatment liquid is radiated downward by 5 to 45 degrees with respect to the horizontal plane. It is configured to discharge outward in the direction, and side wall surfaces are formed on both side surfaces of each divided piece so that an independent discharge flow is formed for each divided piece. It is preferable that a flange surface for attachment is formed on the wall surface of the.

The side wall surface of the divided piece of the casing cover extends to the inside of the discharge casing to form a protrusion, and the discharge casing is formed by the upper end of the protrusion and the mounting flange surface. It is preferable that the cover mounting portion of the upper wall surface is sandwiched and engaged.

According to the submersible mechanical stirring and aerating device of the present invention having the above-mentioned structure, a single submersible mechanical type device is provided by appropriately attaching or detaching the detachable casing cover to the upper portion of the discharge casing. Even with the stirring and aerating device, it is possible to freely change and adjust the ejection direction of the treatment liquid or the fine air. As a result, the same mechanical aerator can be easily adapted to various usage conditions in aeration tanks having different shapes and dimensions.

Further, according to the present invention, since the casing cover is attached to the upper portion of the discharge casing, the apparent diameter (radial dimension) of the discharge port is increased.
The treatment liquid or fine air is discharged from a position radially outward as compared with before the mounting of the casing cover. As a result, the situation in which the entire flow in the aeration tank is largely stirred and the fine air is present only in the limited region is eliminated, and the oxygen transfer efficiency with respect to the entire processing liquid is improved.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a lower suction upper discharge type submersible mechanical aerator generally designated by reference numeral 1 has a suction casing 6. A suction port 40 for the processing liquid is provided below the suction casing 6, and an impeller 5 is provided inside thereof, and a rotary shaft 42 of the impeller 5 is provided vertically. There is.

A discharge casing 2 is attached above the suction casing 6, and a discharge port 21 is provided in the upper circumferential portion (peripheral portion) of the discharge casing 2. The treatment liquid to which the head has been added by the rotation of the impeller 5 is ejected from the ejection port 21 in the radial direction.

Pressure air (indicated by arrow A) is introduced from a blower (not shown) provided outside the aeration tank (not shown in FIG. 1) through the pipe 43, and the pressure air is supplied to the blades in the discharge casing 2. It is mixed in the treatment liquid at the wake of the vehicle 5 (indicated by arrow A1).

When the treatment liquid is discharged from the aerator 1 by the impeller 5, a large amount of air is mixed into the treatment liquid. Then, after being discharged from the aerator 1, the treatment liquid spreads in a plane in the aeration tank in the radial direction. Here, since the processing liquid containing air and having a low density (the processing liquid immediately after being discharged from the aerator 1) rises by exchanging the position with the liquid (in the aeration tank) existing above it, the processing in the tank is performed. The liquid is forcibly stirred. By this action, air is supplied to every corner in the aeration tank, and aerobic microorganisms are activated. Then, organic substances and suspensions in the treatment liquid are adsorbed and decomposed by the action of aerobic microorganisms.

With regard to the configuration and the operation effect up to this point,
This is similar to the conventional submersible mechanical aerator described with reference to FIG. The submersible mechanical aerator 1 according to the embodiment of the present invention differs from the conventional aerator shown in FIG. 11 in the following points.

In FIGS. 1 and 2, the discharge casing 2
Over the entire circumference of the end of the discharge port 21 provided at the upper peripheral edge of
A casing cover 3 is provided. The casing cover 3 has a function of increasing the outer diameter of the discharge port of the aerator 1, and changes the flow direction of the processing liquid ejected from the discharge port from the horizontal direction to the downward direction than the horizontal direction while performing the processing. Exhibits the action of ejecting the liquid radially outward.

The casing cover 3 is divided into a plurality of pieces (six pieces in the illustrated example), and each of the divided pieces of the casing cover 3 (individual parts of the divided casing cover: the same applies hereinafter) is bolted. Is detachably attached to the upper surface of the discharge casing 2.

Further, as shown in FIGS. 3 to 5, the casing cover 3A is constructed so as to form an independent discharge flow for each divided piece. That is, the divided pieces of the casing cover 3A have the side wall surfaces 32 formed on both side surfaces thereof.

Further, the upper wall surface 31 of the divided piece of the casing cover 3A has a downward inclination α toward the outside in the radial direction.
Is added, and the inclination is 5 to 45 degrees downward with respect to the horizontal plane as shown in FIG. In other words, the processing liquid that is discharged radially outward through the divided pieces of the casing cover 3A is formed so as to be discharged 5 to 45 degrees downward with respect to the horizontal plane.

In the embodiment (casing cover 3) shown in FIG. 2, the side wall surfaces 32 on both side surfaces of the cover side wall surface 32 extend linearly in the radial direction. Embodiment 3 (casing cover 3
In A), it is narrowed toward the ejection direction.
As a result, in the embodiments of FIGS. 3 to 5, the ratio of the channel widths is in the range of D / C = 1.3 to 0.4 (“D” and “C” are the flow rates shown in FIG. 3). Is the road width).

A flange surface 35 for mounting is provided on the upper wall surface of the casing cover 3 on the discharge casing 2 side.

In the embodiment shown in FIGS. 6 and 7, a lower wall surface 33 is provided in addition to the side wall surface 32 to guide the discharge flow to the outside.

In the embodiment shown in FIGS. 8 and 9, the side wall surface 32 of the casing cover 3 (the side wall surface of the divided piece of the casing cover) extends to the inside of the discharge casing 2 and the inside of the discharge casing 2 is extended. A protruding portion 34 is formed at. Then, as shown in FIG. 9, the cover mounting portion (2-e: see FIG. 1) on the upper wall surface of the discharge casing 2 is sandwiched and engaged by the upper end portion 34 a of the protruding portion 34 and the mounting flange surface 35. ing.

In other words, referring to FIG.
4, the cover mounting portion of the upper wall surface of the discharge casing 2 shown by reference numeral 2-e in FIG. 1 is fitted in the space 37 defined by the upper end portion 34 a of the mounting flange surface 35 and the mounting flange surface 35. -E is firmly sandwiched and fixed by the upper end portion 34a and the flange surface 35.

With this structure, the casing cover 3 can be firmly attached to the discharge casing 2, the inclination due to the narrowing of the side wall surface 32 is made gentle, and the flow velocity change rate per unit length along the flow direction is small. To reduce the loss. That is, as shown in FIG. 8, the protrusions 34, 34 of the casing covers adjacent to each other form a narrowed flow passage in the discharge casing 2 to gradually reduce the flow passage area, so that the casing cover 3C is provided with a radially outer portion. The flow velocity of the flow of the processing liquid discharged toward one side is increased.

FIG. 10 schematically shows the circulating state of the treatment liquid in the aeration tank 10. By tilting the processing liquid discharge direction radially outward and slightly downward with respect to the horizontal plane by the casing cover described above, and increasing the flow velocity of the flow of the processing liquid discharged radially outward, from FIG. As is apparent, the entire flow of the processing liquid in the aeration tank 10 is largely stirred. As a result, there is no region where the fine air is limited or where there is no fine air.

[0040]

Since the present invention is constructed as described above, a single submersible mechanical stirring aerator can be installed by appropriately attaching or detaching the casing cover detachably attached to the upper portion of the discharge casing. However, it is possible to freely change and adjust the ejection direction of the treatment liquid or the fine air. As a result, the same mechanical aerator can be easily adapted to various usage conditions in aeration tanks having different shapes and dimensions.

That is, by preparing the shape of the casing cover adapted to the shape and size of various aeration tanks, it is possible to well agitate the entire inside of the tank using the same mechanical underwater aerator and to improve the oxygen transfer efficiency. Can be improved.

Further, according to the present invention, by mounting the casing cover, the apparent diameter of the discharge port becomes larger than that before the mounting, that is, the apparent radial position of the discharge port is radially outward. The treatment liquid or fine air is discharged from a position on the outer side in the radial direction as compared with before the mounting of the casing cover. Therefore, the situation where the entire flow in the aeration tank is largely stirred and the fine air exists only in the limited region is eliminated, and the oxygen transfer efficiency is improved with respect to the entire processing liquid. And this casing cover can be adapted to the existing discharge casing.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a plan view showing an embodiment of a casing cover.

FIG. 4 is a front view of FIG.

5 is a sectional view of FIG.

FIG. 6 is a sectional view showing another embodiment of the casing cover.

7 is a front view of FIG.

FIG. 8 is a plan view showing still another embodiment of the casing cover.

9 is a sectional view of FIG.

FIG. 10 is a diagram showing a flow state of the treatment liquid in the aeration tank by the underwater aerator of the present invention.

FIG. 11 is a sectional view showing a conventional submersible mechanical aerator.

[Explanation of symbols]

1, 1A ... Aerator 2 ... Discharge casing 3 ... Casing cover 5: Impeller 6 ... Suction casing 10 ... Aeration tank 31 ... Upper wall 32 ... Side wall surface 33 ... Lower wall 34 ... Projection

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuhiko Ogasawara 11-1 Haneda Asahi-cho, Ota-ku, Tokyo Inside the EBARA CORPORATION (72) Inventor Kaoru Endo 11-1 Haneda-Asahi-cho, Ota-ku, Tokyo No. 11 Incorporated Ebara Corporation (72) Inventor Noriaki Sakai 11-11 Haneda Asahi-cho, Ota-ku, Tokyo Incorporated Ebara Corporation (56) Reference JP-A-8-323385 (JP, A) Actual Kohei 7-17440 (JP, Y2) Actual Kohei Hei 6-42796 (JP, Y2) (58) Fields investigated (Int.Cl. ⁷ , DB name) C02F 3/14-3/26 B01F 1/00- 7/32

Claims (3)

(57) [Claims] 1. A submersion device is installed in the treatment liquid in the aeration tank, and air is introduced from the outside of the aeration tank to be mixed and released into the treatment liquid. At the same time, the treatment liquid in the tank is agitated to be stored in the aeration tank. A lower suction upper discharge type submersible mechanical stirring aerator that mixes fine air into the treatment liquid, a casing cover is provided over the entire circumference of the end of the discharge port provided around the upper portion of the discharge casing of the stirring aerator, The casing cover is configured to guide the flow of the processing liquid to be discharged outward in the radial direction, is divided into a plurality of pieces, and each of the divided pieces is detachably engaged with the upper portion of the discharge casing. A submersible mechanical stirring aerator characterized by 2. The casing cover is configured such that an upper wall surface of the casing cover is inclined downward in a radial direction outward, and the processing liquid is discharged downward in a radial direction by 5 to 45 degrees with respect to a horizontal plane. The side wall surfaces are formed on both side surfaces of each divided piece so that an independent discharge flow is formed for each divided piece, and a flange surface for mounting is formed on the upper wall surface of each divided piece on the discharge casing side. The submersible mechanical stirring aeration apparatus according to claim 1. 3. The side wall surface of the divided piece of the casing cover extends to the inside of the discharge casing to form a protrusion, and the discharge casing is formed by the upper end of the protrusion and the mounting flange surface. The submersible mechanical stirring and aeration apparatus according to claim 2, wherein the cover mounting portion of the upper wall surface is sandwiched and engaged.