JPH0717440Y2 - Mixing / aeration device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention provides an impeller attached to the output shaft end of a submersible motor inside a casing, and a radial outside formed on a discharge casing by rotation of the impeller. A stirring and aeration apparatus for mixing and discharging a liquid and an oxygen-containing gas supplied from a plurality of flow paths facing each other to generate a circulating liquid flow in a tank, and dissolving the oxygen-containing gas in the liquid, particularly a discharge casing The present invention relates to a stirring / aeration device having an improved flow path shape.

[Prior Art] An example of such a device will be described with reference to FIGS. 7 and 8.

In the figure, the discharge casing 3 is installed on the tank bottom A via the extension leg 12 and the leg portion 11.
A plurality of (six in the illustrated example) flow passages B2 are formed at equal intervals around the circumference, and a suction casing 5 is provided above the discharge casing 3. An underwater motor 1 is provided above the suction casing 5, and an impeller 2 is attached to the lower end of the output shaft of the underwater motor 1. The impeller 2 rotates and liquid (white arrow) sucked from the suction casing 5 and oxygen-containing gas discharged from the air discharge part 8 of the air chamber 7 by self-suction from the air supply pipe 6 or forcedly supplied by a blower. A gas (black arrow) is agitated and mixed, and a mixed agitated flow (hatched arrow) is discharged horizontally from the discharge port 9 of the discharge casing 3.

The flow passage B2 has a horizontal vertical cross-section, a plane shape extending outward in the radial direction, and a ratio of the discharge port 9 to the circumference is set to 58%, for example.

[Problems to be Solved by the Invention] As in the above-described conventional apparatus, the discharge casing 3 is extended through the extension leg 12 and the leg portion 11 to the tank bottom A due to the restriction of the blower pressure of the blower or the tank bottom shape of the installed water tank. When installed above, if the flow passage B2 of the discharge casing 3 has a horizontal vertical cross-sectional shape and a planar shape that extends radially outward as described above, (a) the lower side of the discharge casing 3 The area between the tank bottom A and the tank bottom A cannot be sufficiently stirred.

(B) The flow velocity after exiting the discharge port 9 is significantly attenuated, and the reach distance of the discharge flow is short.

(C) The diffusion area of the discharged bubbles during aeration becomes extremely narrow,
There are drawbacks such as reduced oxygen transfer rate and reduced oxygen transfer power efficiency.

As another conventional technique, for example, Japanese Patent Application Laid-Open No. 62-44167 discloses a technique in which a partition surface of a flow channel is devised so that the flow channel does not expand outward. However, it is merely formed so as not to widen outward, and does not solve the above-mentioned drawbacks (a) to (c). In addition to this, since the pressure loss when the fluid to be discharged passes through the flow path is large, there is a problem that the flow velocity of the discharge flow is reduced and the stirring efficiency and the aeration efficiency are reduced.

As still another conventional technique, Japanese Patent Application Laid-Open No. 62-106896 discloses a technique in which a flow path is formed so as to extend obliquely downward from the horizontal when viewed from the side. However, since the flow path in this technique extends horizontally in the discharge port when viewed from the side, the discharge flow of the flow path is injected in the horizontal direction, and most of it does not reach the lower part of the device. . Therefore, there is a problem that the region between the lower part of the device and the bottom part of the water tank cannot be sufficiently stirred.

The present invention has been proposed in view of the various problems in the prior art as described above, and an object thereof is to provide a stirring / aeration device capable of expanding a stirring region and improving aeration performance.

[Means for Solving the Problems] In the stirring / aeration device of the present invention, an axial flow impeller attached to the output shaft end of the submersible motor is provided inside the casing, and the discharge casing is formed by the rotation of the axial flow impeller. In a stirring and aerating device that mixes and discharges the liquid and the oxygen-containing gas supplied from a plurality of flow paths outward in the radial direction to generate a circulating liquid flow in the tank and dissolves the oxygen-containing gas in the liquid When viewed in a plan view, the flow paths are formed radially outward, and the flow path width of the flow paths is constant, and when viewed from the side, the flow paths are from the end part on the impeller side. It is formed so as to extend obliquely downward from the horizontal and extend over the entire area up to the discharge port.

Further, the stirring / aeration device of the present invention is provided with an axial flow impeller attached to the output shaft end of the submersible motor inside the casing, and is directed outward in the radial direction formed in the discharge casing by the rotation of the axial flow impeller. In a stirring and aerating device that mixes and discharges the liquid and the oxygen-containing gas supplied from a plurality of channels to generate a circulating liquid flow in the tank, and dissolves the oxygen-containing gas in the liquid,
The planar shape of the flow passage is formed radially outward in the radial direction, and the flow passage width is formed so as to be narrowed outward in the radial direction. It is formed so as to extend obliquely downward.

[Operation] In the stirring / aeration apparatus of the present invention configured as described above, the planar shape of the flow path is formed radially outward and the vertical cross-sectional shape of the flow path is diagonally downward from horizontal. Since it is formed so as to extend toward the side, the pressure loss when the fluid passes through the flow path is reduced, and the attenuation of the discharge flow velocity is reduced. As a result, the reaching distance of the discharge flow is increased and the stirring area is expanded. Further, if the planar shape of the flow passage is formed so that the flow passage width becomes narrower outward in the radial direction, the flow velocity of the discharge flow increases, and the discharge flow arrival region and the stirring region expand correspondingly.

Further, in the present invention, when viewed from the side, the flow path is formed so as to extend obliquely downward from the horizontal over the entire region from the end on the impeller side to the discharge port. The discharge flow from the discharge port portion does not move in the horizontal direction but becomes a flow obliquely toward the tank bottom, and advances in a region between the casing lower side and the tank bottom to stir. As a result, the flow stagnation portion is eliminated between the lower side of the casing and the bottom of the tank, and the secondary flow entrained in the discharge flow sufficiently agitates.

Then, the reaching distance of the discharge flow is increased, the stirring region is expanded, and the flow stagnant portion is eliminated, so that the discharge bubbles are sent to the deep portion of the tank, that is, the water pressure increasing region.

In addition to this, the flow path of the discharge flow is directed obliquely downward over the entire region from the end part on the impeller side to the discharge port, and is not bent horizontally in the vicinity of the discharge port. Therefore, the bent shape of the discharge flow becomes gentle and the pressure loss decreases.

Further, in the present invention, since the flow passages are formed radially outward, it is possible to suppress the generation of swirling components in the discharge flow. Then, the bubble diffusion performance can be improved, and as a result, the aeration performance can be improved.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, the same members as those shown in FIG. 7 are designated by the same reference numerals, and duplicated description will be omitted.

1 and 2, the discharge casing 4 is formed with a plurality of (six in the illustrated example) flow passages B that are radially formed and are outwardly arranged in a radial direction.

The planar shape of the flow path B is parallel, and the ratio of the discharge port 10 to the circumference is, for example, 55%. The vertical cross-sectional shape of the flow path B is diagonally below horizontal (for example, 22
°) is formed to face.

FIG. 3 shows another embodiment of the present invention, which is a discharge casing 4a.
The planar shape of the flow path B1 is formed radially outward in the radial direction. Here, the width of the flow path B1 is formed so as to narrow outward in the radial direction. Then, the ratio of the discharge port 10a to the circumference is formed to be 28%, for example, and the vertical cross-sectional shape is set to the second.
This is an example formed in the same manner as in the figure.

Since the embodiment shown in FIGS. 1 to 3 is configured as described above, it has the following operational effects.

That is, the reaching distance of the discharge flow can be increased to enlarge the stirring area, and the discharged bubbles can be sent to the deep portion of the tank, that is, the water pressure increasing area to increase the oxygen transfer rate as shown in FIG. In FIG. 4, the air flow rate ratio = air flow rate / reference air flow rate, oxygen transfer speed ratio = oxygen transfer speed according to the present invention / oxygen transfer speed according to a conventional device.

Further, the flow stagnation part in the region between the lower side of the discharge casing and the tank surface is eliminated, and the secondary flow accompanying the discharge flow can sufficiently stir.

Further, the pressure loss of the discharge casing can be reduced, the circulation flow rate can be increased, and the stirring power and the oxygen transfer power efficiency can be reduced as shown in FIGS. 5 and 6. In FIG. 5, agitation power ratio = agitation power according to the present invention / agitation power by the conventional device, and in FIG. 6, oxygen transfer power efficiency ratio = oxygen transfer power efficiency by this device / oxygen transfer power efficiency by a conventional device Is.

Further, even when the apparatus is directly installed on the bottom of the tank without providing extension legs or a pedestal, the same effect as above can be obtained.

[Effects of the Invention] The effects of the present invention are listed below.

(1) The discharge flow velocity increases, the reach of the discharge flow increases,
The stirring area expands.

(2) The pressure loss when the fluid passes through the flow path is reduced.

(3) The attenuation of the discharge flow velocity is low.

(4) The flow stagnation part in the region between the lower side of the casing and the bottom of the tank is eliminated.

(5) The secondary flow entrained in the discharge flow causes sufficient agitation.

(6) The discharged bubbles are sent to the deep part of the tank (water pressure increase area).

(7) The bent shape becomes gentle and the pressure loss decreases.

[Brief description of drawings]

1 to 3 show one embodiment of the present invention, FIG. 1 is a vertical sectional view, FIG. 2 is a plan view of a flow channel, and FIG. 3 is another embodiment of the present invention. Drawing corresponding to FIG. 2, FIG. 4,
FIG. 5 and FIG. 6 respectively show an oxygen transfer rate ratio diagram, an agitation power ratio diagram and an oxygen transfer power efficiency ratio diagram for explaining the effect of the present invention, and FIGS. 7 and 8 show a conventional device, respectively.
It is drawing corresponding to a figure and FIG. B1 ... flow path, 1 ... submersible motor, 2 ... impeller, 4, 4a
...... Discharge casing, 5 …… Suction casing, 6 …… Air supply pipe, 8 …… Air discharge part, 10, 10a …… Discharge port

Claims (2)

[Scope of utility model registration request] 1. An axial flow impeller attached to an output shaft end of a submersible motor is provided inside a casing, and a plurality of radially outward flow passages formed in a discharge casing by rotation of the axial flow impeller are provided. In a stirring / aeration device that mixes and discharges a liquid and a supplied oxygen-containing gas to generate a circulating liquid flow in a tank and dissolves the oxygen-containing gas in the liquid, when viewed in plan, the flow path is outside the radial direction. It is formed radially toward
The width of the flow passage is constant, and when viewed from the side, the flow passage is formed to extend obliquely downward from the horizontal over the entire region from the end on the impeller side to the discharge port. A stirring / aeration device characterized by being used. 2. A casing is provided with an axial flow impeller attached to an output shaft end of a submersible motor, and a plurality of flow passages formed in a discharge casing and directed outward in a radial direction by rotation of the axial flow impeller. In an agitation / aeration apparatus that mixes and discharges a liquid and a supplied oxygen-containing gas to generate a circulating liquid flow in a tank and dissolves the oxygen-containing gas in the liquid, the flow path is radially outward when viewed in plan. Is formed radially toward one side, and the width of the flow channel is narrowed outward in the radial direction, and the flow channel extends obliquely downward from the horizontal when viewed from the side. A stirring and aeration device characterized by being formed.