JP2002079290A - Underwater aeration device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lightweight underwater aeration device reduced in trouble and easy in maintenance and control. SOLUTION: The underwater aeration device 10 is equipped with a casing 12 which has an inflow port 20 and an outflow port 12 for water to be treated and in which a flow channel of water to be treated is demarcated, the water sending impeller 26 provided in the casing in a rotatable manner, an air supply pipe 66 for introducing air into the casing, an underwater electromotor 28 for rotationally driving the impeller and the rotational speed control circuit 42 such as an inverter or the like arranged in the underwater electromotor or in the hermetically closed space 44 provided adjacent to the underwater electromotor to control the rotational speed of the underwater electromotor. In this constitution, since the rotational speed of the underwater electromotor is controlled by the rotational speed control circuit reduced in trouble used in place of a gear type speed reducer, the device is made lightweight and can be controlled corresponding to various conditions such as water quality or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underwater aeration device used in liquid treatment facilities such as a sewage treatment plant, a human waste treatment plant, a rural settlement wastewater treatment plant, a fishing village settlement wastewater treatment plant, and an industrial wastewater treatment plant.

[0002]

2. Description of the Related Art An underwater aeration apparatus is used in a water treatment tank such as a biological reaction tank using aerobic microorganisms, is guided by a guide pipe, is lowered into the water to be treated, and is installed at the bottom of the tank. To be served. During operation, the underwater aeration device agitates the water to be treated and causes bubbles to accompany the flow of the water to be treated.

[0003] A variety of such underwater aeration devices have been known in the art, and basically include a casing having an inlet and an outlet for treated water and having a passage for treated water formed therein. And an impeller for water supply disposed therein, an underwater motor for rotating the impeller, and an air supply pipe for supplying gas such as air into the casing. Further, a conventional general underwater aeration apparatus includes a gear type speed reducer directly connected to an underwater electric motor in order to make the rotation speed of the impeller appropriate. In such a configuration,
When the impeller is driven to rotate by the underwater motor, the water to be treated is taken into the casing and discharged from the outlet together with the air bubbles introduced from the air supply pipe to the outside of the casing.

[0004]

Since the above-mentioned conventional underwater aerator has a gear type speed reducer, it is necessary to protect the gears and other components by isolating the speed reducer from the water to be treated. was there. For this reason, conventionally, the speed reducer is housed in a closed space, and an oil seal, a mechanical seal, or the like is provided around the output shaft.

[0005] However, if the oil seal or the mechanical seal is damaged, the components of the speed reducer may come into contact with the water to be treated, leading to corrosion and abrasion, leading to failure.

In addition, since the gear type speed reducer is heavy, it requires a great deal of power when the underwater aeration device is pulled up onto the treatment tank for maintenance and maintenance, and the maintenance is time-consuming. There's a problem.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an underwater aeration apparatus that has few failures, is lightweight, and is easy to maintain.

[0008]

In order to achieve the above object, an underwater aeration apparatus according to the present invention has an inlet and an outlet for water to be treated and a flow path for the water to be treated inside. A casing formed, an impeller rotatably provided in the casing and forming a flow of the water to be treated from the inlet to the outlet in the flow path, and a gas accompanying the water to be treated flowing in the flow path An air supply pipe for introducing a gas into the casing to cause the motor to rotate, an underwater motor having an output shaft connected to the impeller to rotationally drive the impeller, and a submersible motor or a closed space provided adjacent to the underwater motor. A control circuit for controlling the rotation speed of the underwater motor.

In such a configuration, since the rotation speed of the underwater motor is controlled by a rotation speed control circuit such as an inverter instead of the gear type speed reducer, the weight of the device can be reduced, and water quality and the like can be reduced. Control according to various conditions becomes possible. Further, since the rotation speed control circuit is built in the underwater aeration apparatus, handling becomes easy.

Further, according to the present invention, the output shaft of the underwater motor is directly connected to the impeller without passing through the speed reducer, so that the bearing portion on the load side (that is, the impeller side) of the output shaft is mechanically sealed. It is preferable to double seal watertight with an oil seal.

Further, when the closed space is provided adjacent to a bearing portion on the non-load side of the output shaft of the underwater motor, a wall body defining the closed space and fixing a control circuit; It is preferable that a predetermined gap is formed between the bearing and the bearing on the non-load side.

When such a gap is formed, the water to be treated flows through the gap, and the bearing portion and the control circuit can be water-cooled.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 1, an underwater aeration apparatus 10 according to the present invention is of an upward flow type, and has a casing 12 in which a flow path of water to be treated is formed. The casing 12 includes a body casing 14 whose upper part is flared and a flared upper casing 18 that forms an outlet 16 for water to be treated in cooperation with the flared upper part of the body casing 14. It is composed of In addition, the lower end of the body casing 14 is opened to serve as an inlet 20 for the water to be treated.

The lower end of the flare-shaped upper casing 18 terminates at the middle part of the body casing 14 in the vertical direction, and a cup-like member 22 is disposed adjacent to the lower part of the casing with the open end facing downward. 12 and rotatably arranged. A plurality of blades 24 are attached to the outer peripheral surface of the cup-shaped member 22, and constitute an impeller 26 for water supply.

The upper part of the casing 12 has an impeller 2
An AC type underwater motor 28 as a driving means 6 is fixed by bolts or the like. The output shaft 30 of the underwater electric motor 28 is disposed coaxially with the casing 12, extends downward, passes through the closed end of the cup-shaped member 22, and is fixed thereto.
The output shaft 30 of the underwater motor 28 is surrounded by a seal box 34 extending below a housing (hereinafter referred to as “motor housing”) 32 of the underwater motor 28.
In the seal box 34, a mechanical seal portion 36 is provided.
And an oil seal portion 38, and the bearing portion 40 of the output shaft 30 and the inside of the motor housing 32 are hermetically sealed by the double seal portion.

In this embodiment, no mechanical speed reducer is provided between the underwater motor 28 and the impeller 26. Further, an inverter circuit 42 is used instead of the speed reducer. Here, the inverter circuit 42 is a circuit that converts an AC from an AC power supply into a DC with a rectifier or the like, and then returns the AC to an arbitrary frequency by switching using a semiconductor device or the like, and arbitrarily changes the output frequency. Therefore, the rotation speed of the underwater motor 28 can be freely controlled.

The inverter circuit 42 is disposed adjacent to the upper side of the underwater motor 28, that is, on the side opposite to the output shaft 30. Further, the inverter circuit 42 includes a cover box 44.
Covered by An outward flange 46 is provided at the lower end of the cover box 44.
6 is the outward flange 4 at the upper end of the motor housing 32.
The cover box 44 is attached to the motor housing 32 by connecting the cover box 44 with bolts or the like. In the illustrated embodiment, a disc-shaped plate 50 is disposed between the cover box 44 and the motor housing 32. The plate 50 serves as an end plate of the motor housing 32 and an end plate of the cover box 44. The plate 50 partitions the inside of the underwater motor 28 and the inside of the cover box 44, and makes them both closed spaces.

Although not shown, the flanges 46, 48
A packing or gasket-like seal member is disposed between the flange, the flange 48 and the plate 50, and between the flange 46 and the plate 50, so that the inside of the underwater motor 28 and the inside of the cover box 44 are kept watertight.

The inverter circuit 42 includes a power supply cable 52 extending from an external AC power supply (not shown),
Frequency control cable 54 extending from an external manufacturing device
And are connected. For this reason, through holes 56 and 58 are provided at appropriate places of the cover box 44, and these through holes 56 and 58 are sealed watertight by appropriate sealing means 60 and 62. When a small motor is used, the power supply cable 52 for power and the cable 54 for frequency control are combined into one, and only one through hole is opened in the cover box 44 and connected to the inverter circuit 42. You can also.

A wiring 64 for connecting the output terminal of the inverter circuit 42 and the input terminal of the underwater motor 28 in the motor housing 32 is provided on the disc-shaped plate 50.
A through-hole 66 is formed for passing the through-hole, and this through-hole 66 is also sealed by a suitable sealing means (not shown).

Further, the underwater aeration apparatus 10 has an air supply pipe 66 for introducing a gas such as air into the casing 12.
have. One end of the air supply pipe 66 is connected to an external blower (not shown), and the other end is inserted from below the casing 12 into the cup-shaped member 22 and arranged. In the upper part of the side wall of the cup-shaped member 22, a plurality of air diffusion holes 68 are formed at equal intervals in the circumferential direction. The gas introduced into the cup-shaped member 22 through the air supply pipe 66 is dispersed in the casing 12 by these air diffusion holes 68.

In the figure, reference numeral 70 denotes an underwater aeration device 10.
This is an eye ring to which a chain 72 for raising and lowering the garment is attached. Reference numeral 74 is a guide member,
It has a through hole 78 through which a guide vip 76 for guiding the underwater aeration apparatus 10 when the underwater aeration apparatus 10 is raised and lowered.

Next, a description will be given assuming that the underwater aeration apparatus 10 having the above configuration is used in a biological reaction tank for performing sewage treatment by aerobic microorganisms.

The biological reaction tank contains water to be treated containing sludge composed of aerobic microorganisms. In the tank, the underwater aeration apparatus 10 is suspended by a chain 72, lowered by a guide pipe 76, and lowered at the bottom of the tank. Installed in

Then, power is supplied to the inverter circuit 42 through the power supply cable 52, and a frequency control signal is transmitted through the control cable 54. As a result, an AC having a frequency corresponding to the control signal is output from the inverter circuit 42 to the underwater motor 28, and the output shaft 30 of the underwater motor 28 rotates at a desired rotation speed.

When the underwater motor 28 is driven, the output shaft 3
The impeller 26 rotates with 0, and an upward water flow of the water to be treated is generated. That is, the water to be treated is pumped up from the inflow port 20 at the lower part of the casing 12 and is discharged from the upper outflow port 16 substantially horizontally outward through the flow path in the casing 12.

On the other hand, the blower is driven and air is supplied to the air supply pipe 6.
Supplied from 6. This air temporarily stays in the space inside the cup-shaped member 22 to form an air pool. Then, the air is pushed out from all the diffusing holes 68 to the flow path side as an air mass.
This air mass is sheared by the inner edge of the air diffusing hole 68 on the side wall of the rotating cup-shaped member 22 to become bubbles. Then, the bubbles are mixed with the water to be treated rising in the flow path to form a steam-water multiphase flow, and are discharged from the outlet 16. As a result, a circulating flow of the gas-water mixed phase flow is generated in the biological reaction tank, and sufficient oxygen is supplied to the entire water to be treated, thereby promoting the decomposition reaction of the water to be treated by the aerobic microorganisms.

By the way, the biological reaction tank has the inferred inflow, temperature,
Depending on various conditions such as water quality, it may be necessary to adjust the dissolved oxygen value in the water to be treated. Even in such a case, since the inverter circuit 42 is used, the rotation speed of the underwater electric motor 28 can be adjusted arbitrarily. Therefore, the flow rate of the water to be treated flowing through the flow path in the casing is changed to reduce the dissolved oxygen value. It can be adjusted. This enables various operation managements.

Further, since the inverter circuit 42 is considerably lighter than the gear type speed reducer, the weight of the underwater aerator 10 itself is greatly reduced. Therefore, it is easy to install the underwater aeration apparatus 10 and to pull up the apparatus for maintenance. Further, since the inverter circuit 42 is integrated with the underwater aeration apparatus 10, the handling is easy, and since the inverter circuit 42 is disposed in the closed space of the underwater aeration apparatus 10, there is an advantage that the number of failures is extremely small. Of course, the inverter circuit 42
Does not suffer from corrosion and abrasion unlike the gear type speed reducer. Further, since the inverter circuit 42 is heated, a cooling fan is generally provided for a motor with a built-in inverter. However, in the present invention, since the inverter circuit 42 is provided in water, the inverter circuit 42 is cooled by a water cooling effect, and the cooling fan is cooled. Another advantage is that the fan can be eliminated.

Although the underwater aeration apparatus 10 of the above embodiment is of the upward flow type, the present invention can be applied to other types, for example, the downward flow type. FIG. 2 is a cross-sectional view showing a downflow type underwater aeration apparatus 100 to which the present invention is applied. In the downward flow type underwater aeration apparatus 100, the casing 112
The upper opening is an inlet 120 for the water to be treated, and the lower opening is an outlet 116. An impeller 126 for downward water supply is disposed in an intermediate portion of the casing 112,
A rotating cone 180 is provided downstream of the impeller 126. The rotating cone 180 and the casing 11
An air ejection gap 182 is formed between the air ejection gap 182 and the bottom of the second air jet. An air supply pipe 166 for supplying air is provided below the rotary cone 180, and a space surrounded by the rotary cone 180 and the bottom wall of the casing 112 is an air chamber.

Although the above is a known configuration, according to the present invention, as in the configuration of FIG.
30 is directly connected to the impeller 126. Also,
A closed space is formed by a cover box 144 at a position adjacent to the upper side of the underwater motor 128, and an inverter circuit 142 for controlling the rotation speed is disposed therein. In FIG. 2, the same or corresponding parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description will be omitted.

In the downflow type underwater aeration apparatus 100 configured as described above, the output shaft 130 of the underwater motor 128 is set to a predetermined rotation speed by the inverter circuit 142, and rotates the impeller 126 and the rotary cone 180. The water to be treated is sent downward in the casing 112 by the impeller 126 and is discharged from the outlet 116 at the lower part of the casing 112. At this time, air is injected from the air supply pipe 166 into the air chamber in the rotary cone 180, and the air ejection gap 182
When the liquid is ejected from the rotary cone 180 into the flow path, the thin film is formed by the centrifugal force of the rotary cone 180 rotating at high speed, and is sheared by the peripheral end of the rotary cone 180. Further, the air jetted into the flow path is crushed by the water flow from above to become fine bubbles, and is transported in the direction of the outlet 116 of the casing 112 to be discharged into the processing tank. Needless to say, the configuration in FIG. 2 is also light, similarly to the configuration in FIG. 1, and the handling during maintenance and installation is significantly improved.

FIG. 3 is a longitudinal sectional view showing still another embodiment of the underwater aeration apparatus according to the present invention, and FIG.
FIG. 4 is a sectional view taken along line IV. The underwater aeration apparatus 200 shown in FIGS. 3 and 4 is basically similar to the underwater aeration apparatus except that a gap is formed between a closed space for accommodating a control circuit such as an inverter circuit 42 and the motor housing 32 of the underwater motor 28. Is similar to the underwater aeration apparatus 10 shown in FIG. Therefore, in the configurations of FIGS. 3 and 4, the same or corresponding parts as those of FIG. 1 are denoted by the same reference numerals, and detailed description will be omitted.

Underwater aeration apparatus 200 in this embodiment
Now, as shown in FIG. 3 and FIG.
The plate 250 that partitions the enclosed space accommodating the motor housing 32 and the internal space of the motor housing 32 is
51, a disk-shaped lower part 253, and 1
This is a metal integrally molded product including the pair of vertical ribs 255. Further, a reinforcing rib 257 extending outward from the central portion of the vertical rib 255 and connecting the upper portion 251 and the lower portion 253 is provided integrally.

A cover box 44 is fixed to the upper part 251 of the plate 250 in a watertight manner, and the inverter circuit 42 is accommodated therein to form a closed space. It is preferable that the inverter circuit 42 be fixed to the upper portion (the wall defining an enclosed space) 251 via a metal plate 263 made of a material having good heat conductivity, for example, copper or aluminum. Alternatively, it may be directly bonded and fixed to the upper portion 251 of the plate 250 with an adhesive made of silicon resin having excellent heat conductivity.

The lower portion 253 of the plate 250 constitutes an end plate of the motor housing 32, and a lower surface thereof has a bearing rotatably supporting an end on the non-load side of the output shaft 30 of the underwater motor 28. A part 261 is provided.

The pair of vertical ribs 255 are arranged in parallel at a predetermined interval from each other. These vertical ribs 255
Is preferably a position along the edge of the inverter circuit 42, as shown in FIG.

When the underwater aeration apparatus 200 having such a configuration is immersed in a storage tank such as a biological reaction tank and the underwater motor 28 is driven, the water to be treated in the storage tank starts to circulate. Thereby, the upper part 251 and the lower parts 253 and 1 of the plate 250
The water to be treated flows through the gap 259 defined by the pair of vertical ribs 255. The inverter circuit 42 generates high heat,
The heat is transferred to the metal plate 263 and the plate 25 having good heat conductivity.
The inverter circuit 42 is efficiently cooled because it is absorbed by the water to be treated flowing along the lower surface of the upper part 251 via the upper part 251 of the zero. As a result, the performance of the inverter circuit 42 is stabilized, and an increase in power consumption can be suppressed.

The water to be treated flowing along the lower portion 253 of the plate 250 also absorbs heat generated by the bearing 261 of the underwater motor 28 provided in the lower portion 253. Therefore, it is possible to extend the life of the bearing portion 261 and the life of the underwater motor 28.

The shape of the gap formed between the part accommodating the control circuit such as the inverter circuit 42 and the underwater motor 28 is not limited to those shown in FIGS. It can be changed as appropriate in consideration of the direction, speed, etc.

Although some preferred embodiments of the present invention have been described in detail, it goes without saying that the present invention is not limited to the above embodiments.

For example, in the above embodiment, the inverter circuit 42 is arranged in a closed space formed separately from the inside of the motor housing 32. However, the degree of sealing in the motor housing 32 can be maintained. If heat generation of the inverter circuit does not cause a problem, it may be arranged in the motor housing 32. Further, by eliminating the supply system of gas such as air, the underwater aeration apparatus according to the present invention can also function as an underwater stirring apparatus.

[0044]

As described above, according to the present invention, since a control circuit such as an inverter circuit is provided in place of a mechanical speed reducer, the weight of the underwater aerator can be reduced. Therefore, it is easy to install and lower the underwater aeration device for maintenance and maintenance, and work efficiency is significantly improved.

Further, since the inverter circuit can finely control the rotation speed of the underwater motor, a desired operation performance can be easily obtained, and the processing capacity of the device can be improved.

Furthermore, unlike a mechanical type speed reducer, the inverter circuit has no troubles such as wear and the like, and even if a trouble occurs, it can be easily replaced, so that it can be used for a long time.

When a control circuit such as an inverter circuit generates high heat, a gap is provided between the enclosed space for accommodating the control circuit and the underwater motor to efficiently control the control circuit and the underwater motor. The bearing can be cooled,
It is possible to stabilize the performance of the control circuit and extend the life thereof, and to extend the life of the bearing portion of the underwater motor.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view showing an upward flow type underwater aeration apparatus according to the present invention.

FIG. 2 is a longitudinal sectional view showing a downflow type underwater aeration apparatus according to the present invention.

FIG. 3 is a longitudinal sectional view showing another embodiment of the upward flow type underwater aeration apparatus according to the present invention.

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3;

[Explanation of symbols]

10, 100, 200 ... underwater aeration device, 12, 112 ...
Casing, 16, 116 ... Outlet, 20, 120 ... Inlet, 26, 126 ... Impeller, 28, 128 ... Underwater motor, 30, 130 ... Output shaft, 32 ... Seal box, 36 ... Mechanical seal, 38 ... Oil seal , 4
0: bearing part, 42, 142 ... inverter circuit, 44, 1
44: cover box (closed space), 66, 166: intake pipe, 250: plate, 259: gap.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01F 7/22 B01F 7/22 15/00 15/00 A C02F 3/20 C02F 3/20 Z (72) Inventor Kin Tomita 5-9-11, Kitashinagawa, Shinagawa-ku, Tokyo Sumitomo Heavy Industries, Ltd. (72) Inventor Toshihiko Abe 5-9-11, Kitashinagawa, Shinagawa-ku, Tokyo Sumitomo Heavy Industries, Ltd. 72) Inventor Norio Yamaguchi 2-36-40 Shimomaruko, Ota-ku, Tokyo F-term in Unosawa Gumi Iron Works (Reference) 4D029 AA09 AB05 CC06 CC07 4G035 AA01 AB14 AE02 4G037 AA01 DA01 EA04 4G078 AA13 AB20 BA05 CA19 CA19 CA20 DB08 EA10

Claims (3)

[Claims] 1. A casing in which an inlet and an outlet for water to be treated are formed and a flow path for the water to be treated is defined therein; and a casing rotatably provided in the casing, wherein An impeller that forms a flow of the water to be treated from the inflow port to the outflow port, and an air supply pipe that introduces the gas into the casing so that the gas to be treated accompanies the water to be treated flowing in the flow path. A submersible motor having an output shaft connected to the impeller to rotationally drive the impeller, and disposed in the submersible motor or in a closed space provided adjacent to the submersible motor, for controlling a rotation speed of the submersible motor. An underwater aeration apparatus comprising: a control circuit. 2. The underwater aeration apparatus according to claim 1, wherein a bearing portion of the underwater motor on a load side of the output shaft is water-tightly sealed by a mechanical seal and an oil seal. 3. A wall defining the enclosed space and fixing the control circuit when the enclosed space is provided adjacent to a bearing portion of the underwater motor on a non-load side of the output shaft. The underwater aeration device according to claim 1 or 2, wherein a predetermined gap is formed between the body and a bearing portion on the non-load side of the output shaft.