JP2021154242A - Impeller - Google Patents

Abstract

To provide an impeller capable of decreasing power necessary for its rotation by improving efficiency of feeding oxygen to water to be treated.SOLUTION: The impeller that aerates and/or agitates water to be treated and comprises: a shaft; a plurality of blade parts each extending from the shaft to the radial-direction outside; and a plurality of connection plates each disposed between two blade parts neighboring with each other in a circumferential direction to connect the two blade parts. A gap is formed between each of the connection plates and the shaft. An end part on the radial-direction outside of each of the connection plates is disposed at a position on the radial-direction outside further than 90% of the whole length of the blade part which is a length between the shaft and the end part on the radial-direction outside of the blade part, when viewed from the axial direction.SELECTED DRAWING: Figure 5A

Description

The present invention relates to an impeller of a vertical axis type aeration stirrer for biological water treatment equipment.

As a biological treatment facility for biologically treating water to be treated such as sewage and sewage, a method of using an oxidation ditch tank in which a non-terminal circulating water channel is formed is known. Three types of aeration stirring devices in this oxidation ditch tank are known: a vertical axis type, a horizontal axis type, and an oblique axis type.
In Patent Document 1, an impeller that is arranged in an oxidation ditch tank and rotates about a direction substantially perpendicular to the liquid surface of waste water, that is, a direction intersecting the liquid surface as an axial direction to aerate and agitate the waste water. Is described.

Japanese Unexamined Patent Publication No. 2019-005728

In order to aerate and agitate the water to be treated in the oxidation ditch tank, it is necessary to keep the aeration agitator in operation for a long time. Therefore, it is desired that the impeller, which is in constant contact with the water to be treated, improves the efficiency of supplying oxygen to the water to be treated without increasing the power of the aeration agitator.

Therefore, an object of the present invention is to provide an impeller capable of reducing the power required for rotation by improving the supply efficiency of oxygen to the water to be treated.

As a result of diligent studies on the above problems, the present inventor has found that in an impeller provided with a plurality of blades extending radially outward from the shaft and a connecting plate connecting the plurality of blades, the position of the radial outer end of the connecting plate. The present invention has been completed by finding that the efficiency of supplying oxygen to the water to be treated can be improved by installing the above in the radial direction of the impeller. That is, the present invention is the following impeller.

The impeller of the present invention for solving the above problems is an impeller that agitates and / or agitates the water to be treated, and includes a shaft, a plurality of blades extending radially outward from the shaft, and a circumferential direction. A plurality of connecting plates that are arranged between two adjacent blades and connect the two blades are provided, and a gap is formed between the connecting plate and the shaft. The radial outer end of the connecting plate is radially outer than 90% of the length of the blade having the total length from the shaft to the radial outer end of the blade when viewed from the axial direction. It is characterized by being installed at the position of.

According to the impeller of the present invention, since the radial outer end of the connecting plate extends to the vicinity of the end of the blade portion, it is strong against the water to be treated moving on the upper surface of the connecting plate due to the rotation of the impeller. Centrifugal force is applied. Therefore, the water to be treated is more accelerated on the upper surface of the binder plate and can be scattered over a long distance. As a result, a large amount of oxygen is taken into the water to be treated, and oxygen can be efficiently supplied to the water to be treated.
In other words, when the vertical axis type aeration agitator is operated while keeping the oxygen supply amount constant, the rotation speed of the impeller can be suppressed, so that the power supply required for the rotation of the impeller is suppressed low. It becomes possible.
Therefore, according to the impeller of the present invention, it is possible to effectively increase the oxygen supply efficiency.

In the impeller of the present invention for solving the above problems, the length of the gap from the shaft to the connecting plate is 40 to 70 of the length from the shaft to the radial outer end of the connecting plate when viewed from the axial direction. It is characterized by being%.
According to this feature, the size of the water passage hole formed by the gap from the shaft to the connecting plate becomes an appropriate size from the viewpoint of effectively increasing the oxygen supply efficiency. In other words, the length of the gap from the shaft to the connecting plate is 40% or more of the length from the shaft to the radial outer end of the connecting plate, so that a water passage hole that can secure a sufficient amount of pumped water is provided. Can be formed. In addition, the length of the gap from the shaft to the connecting plate is 70% or more of the length from the shaft to the radial outer end of the connecting plate, so that the radial length of the connecting plate is sufficiently secured. Therefore, the water to be treated is accelerated on the upper surface of the connecting plate, and the droplets of the water to be treated can be scattered over a long distance.
Therefore, according to the impeller of the present invention, it is possible to effectively increase the oxygen supply efficiency.

Further, one embodiment of the impeller of the present invention is characterized in that the blade portions are provided on both the upper surface side and the lower surface side of the connecting plate.
According to this feature, the water to be treated pumped from the water passage holes by the blades provided on both the upper surface side and the lower surface side of the connecting plate is scattered around the impeller, so that the oxygen supply efficiency is improved. It is possible to increase it effectively.
In addition, since the water to be treated is agitated by the blades provided on the lower surface side of the connecting plate, the water to be treated to which a large amount of oxygen is supplied by scattering is mixed with the water to be treated flowing in the flow path. Can be done. As a result, oxygen can also be supplied toward the bottom in the flow path.

According to the present invention, it is possible to provide an impeller capable of reducing the power required for rotation by improving the supply efficiency of oxygen to the water to be treated.

It is a schematic explanatory drawing which shows the structure of the biological treatment equipment of this invention when an unterminated water channel is seen from a plane. It is a schematic explanatory drawing which shows the structure of the vertical axis type aeration agitator of this invention in the cross section of an unterminated water channel. It is a schematic perspective view which shows the impeller in the 1st Embodiment of this invention. It is a schematic plan view which shows the impeller in the 1st Embodiment of this invention. FIG. 3B is a schematic cross-sectional view in the VV direction of FIG. 3B showing an impeller according to the first embodiment of the present invention. It is a schematic cross-sectional view in the VV direction of FIG. 3B which shows the impeller in the 1st Embodiment of this invention, and is the schematic explanatory view for demonstrating the position of the end portion of the connecting plate. It is a schematic perspective view which shows the impeller in the 2nd Embodiment of this invention. It is a schematic plan view which shows the impeller in the 2nd Embodiment of this invention. It is the schematic sectional drawing in the VV direction of FIG. 4B which shows the impeller in the 2nd Embodiment of this invention. It is a schematic cross-sectional view in the VV direction of FIG. 4B which shows the impeller in the 2nd Embodiment of this invention, and is the schematic explanatory view for demonstrating the size of a gap. It is a schematic perspective view which shows the impeller in the 3rd Embodiment of this invention. It is a schematic plan view which shows the impeller in the 3rd Embodiment of this invention. It is the schematic sectional drawing in the VV direction of FIG. 4B which shows the impeller in the 3rd Embodiment of this invention. It is a schematic cross-sectional view in the VV direction of FIG. 4B which shows the impeller in the 3rd Embodiment of this invention, and is the schematic explanatory view for demonstrating the position of the end portion of the connecting plate and the size of a gap. It is a schematic perspective view which shows the existing impeller. It is a schematic plan view which shows the existing impeller. FIG. 6B is a schematic cross-sectional view showing an existing impeller in the VV direction of FIG. 6B. It is a graph which shows the result of the simulation of Example 1 of this invention. It is a graph which shows the result of the simulation of Example 2 of this invention.

[First Embodiment]
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic explanatory view showing a configuration of a biological treatment facility 1 when the non-terminal water channel 2 in the first embodiment is viewed from a plane. The arrows in the figure represent the circulating flow flowing through the non-terminal water channel 2.

(Biological treatment equipment)
The biological treatment equipment 1 in the present invention is used for the oxidation ditch method in which biological treatment is performed while circulating the water to be treated in the non-terminal water channel 2. The water to be treated is not particularly limited, and examples thereof include organic wastewater such as sewage, livestock wastewater, and factory wastewater.
As shown in FIG. 1, the biological treatment equipment 1 includes an endless water channel 2 formed by a peripheral wall 21 and a partition wall 22, a vertical axis type aeration agitation device 3 installed in the endless water channel 2, and a guide plate 7. There is.

The non-terminal water channel 2 is composed of two linear water channels 2a extending in parallel and a circulation water channel 2b that connects the straight water channels 2a at both ends of the two straight water channels 2a to form a circulating flow to be treated.
In the biological treatment equipment 1 of the first embodiment, the vertical axis type aeration stirring device 3 is installed in the vicinity of the partition wall 22 of the straight water channel 2a. The vertical axis type aeration stirring device 3 may be arranged in the circulation flow path 2b.

The vertical axis type aeration stirring device 3 performs surface aeration on the water to be treated in the flow path and supplies oxygen to the water to be treated. Further, the vertical axis type aeration stirring device 3 forms a circulating flow in the non-terminal water channel 2 together with the guide plate 7 arranged in the vicinity. Specifically, the vertical axis type aeration stirring device 3 generates a stirring flow in the water to be treated, and the flow of the stirring flow is guided by a guide plate 7 arranged in the vicinity to circulate in the non-terminal water channel 2. Form a stream.

(Vertical axis type aeration stirrer)
FIG. 2 is a schematic explanatory view showing the structure of the vertical axis type aeration stirring device 3 in this embodiment. As shown in FIG. 2, the vertical axis type aeration stirring device 3 includes an impeller 31 for aeration-stirring the water to be treated and a drive unit 33 for supplying power for rotating the impeller 31.
Further, the impeller 31 in the present embodiment includes a shaft 31C connected to the drive unit 33, a plurality of blade portions 31A radially attached to the shaft 31C, and a connecting plate 31B connecting the plurality of blade portions 31A.

Further, FIG. 3A shows a perspective view of the impeller 31 of the first embodiment of the present invention, and FIG. 3B shows a plan view of the impeller 31 of the first embodiment of the present invention as viewed from the axial direction. .. As shown in FIGS. 3A and 3B, the connecting plate 31B is installed between the connecting plate 31B and the shaft 31C via a gap, and this gap forms a water passage hole 31D for pumping the water to be treated. ..

Next, the operation of the vertical axis type aeration stirring device 3 will be described.
As shown in FIG. 2, the vertical axis type aeration stirring device 3 is installed so that the water passage hole 31D is arranged in the water to be treated and the tip of the blade portion 31A is exposed on the water surface. When the impeller 31 is rotated at this position, the water to be treated attracted by the blade portion 31A is scattered from the tip of the blade portion 31A to the surroundings by centrifugal force. The guide plate 7 arranged in the vicinity of the vertical axis type aeration stirring device 3 is installed so that the upper end is located near the water surface, and the droplets of the water to be treated are scattered beyond the guide plate 7 to a distant place. Can be done. The droplets of the water to be treated take in air while scattering in the atmosphere, and land on the water to be treated in a state containing air. As a result, oxygen can be supplied to the water to be treated.

When the water to be treated is scattered from the blade portion 31A, the water to be treated flows from the water passage hole 31D formed between the connecting plate 31B and the shaft 31C, so that the water to be treated is continuously scattered around the impeller 31. Can be done.

Further, the blade portion 31A located in the water to be treated forms a stirring flow in the water to be treated. The agitated flow is guided toward the downstream side by the guide plate 7 and forms a circulating flow in the non-terminal water channel 2.

Next, each part of the impeller 31 will be described in detail.
<Axis>
As shown in FIG. 2, the shaft 31C is connected to the drive unit 33, and is intended to rotationally drive the impeller 31 by the power from the drive unit 33.
The shape and the like of the shaft 31C are not particularly limited as long as the impeller 31 can be rotationally driven by the power from the drive unit 33. For example, those having a shape such as a columnar shape or a polygonal columnar shape can be mentioned. Further, the shaft 31C may have a hollow structure having a hollow inside. In this case, since the weight of the entire impeller 31 can be reduced while maintaining the strength of the shaft 31C, the water to be treated can be aerated and agitated with low power.

The material of the shaft is not particularly limited, and examples thereof include metal such as iron and stainless steel, and resin such as hard plastic. From the viewpoint of strength and corrosion resistance, corrosion-resistant metals such as stainless steel are preferable.

As shown in FIG. 2, the shaft 31C is composed of a plurality of shafts, and includes a connecting portion 31E that connects the plurality of shafts. By making the shaft 31C divisible into a plurality of shafts, the position of the impeller 31 with respect to the water depth can be adjusted. For example, when the impeller 31 is installed near the bottom of the water to be treated, the connecting portion 31E can be divided and a shaft (not shown) for stretching can be added to stretch the length of the shaft 31C. can.

Further, as shown in FIG. 2, the elevating device 31F may be provided. The elevating device 31F is a device for elevating and lowering the impeller 31, and by providing the elevating device 31F, the height position of the impeller 31 can be finely adjusted. By finely adjusting the height of the impeller 31, the amount of droplets formed by the impeller 31 and the scattering distance can be adjusted. Therefore, by improving the oxygen supply efficiency to the water to be treated, the power required for rotation can be adjusted. The effect of the present invention, which is to reduce the amount of oxygen, can be more exerted.

<Hane part>
As shown in FIG. 3A, the blade portion 31A is formed so as to extend radially outward from the shaft 31C, and a plurality of blade portions 31A are attached to the shaft 31C. In the impeller 31 of the first embodiment, the blade portion 31A is composed of two plate members of the blade plate 310A and the blade plate 310B, and the plate surface of the blade plate 310A is substantially parallel to the axial direction (substantially vertical direction). Will be installed. The blade plate 310B is formed continuously with the upper end portion of the blade plate 310A, and is installed so as to be inclined from the blade plate 310A toward the front in the rotation direction of the impeller 31. Further, as shown in FIG. 3B, the blade plate 310A (up to the broken line) is fixed radially from the axis of the shaft 31C. By fixing the blade plate 310A radially from the axis, it is easy to balance the impeller 31 during rotation.

The blade plate 310A and the blade plate 310B may be formed by bending one plate member, or may be formed by combining different plate members. When one plate member is bent to form the blade portion 31A, the strength of the entire blade portion 31A can be kept high. Further, when forming by combining different plate members, it is possible to change the shape to various shapes by exchanging each blade plate.

Further, as shown in FIG. 3C, the blade portion 31A is inclined upward from the shaft 31C toward the outside in the radial direction of the impeller. As a result, the water to be treated can be scattered far away, so that the oxygen supply rate efficiency can be improved. The angle formed by the blade portion 31A and the water surface of the water to be treated is, for example, 10 to 80 °, preferably 20 to 60 °.

Further, in the shape of the lower end of the blade plate 310A, the width of the blade plate 310A expands from the radial outer tip toward the shaft 31C. As a result, the blade plate 310A becomes large in the vicinity of the shaft 31C arranged inside the water to be treated, so that a strong stirring flow can be formed.

The number of blades 31A installed is not particularly limited. The number of blades 31A to be installed is preferably about 2 to 12 at equal intervals when the impeller 31 is viewed in a plan view. In this case, the water to be treated can be effectively agitated and scattered in the atmosphere. More preferably, the number of impellers 31 installed is 6 to 8 at equal intervals when the impellers 31 are viewed in a plan view. In this case, the strength of the agitated flow generated and the amount of the water to be treated scattered in the atmosphere are optimized, so that the water to be treated can be aerated and agitated efficiently.

Further, as shown in FIG. 3A, a connecting plate 31B is connected between the blade plates 310A adjacent to each other in the circumferential direction. The connecting plate 31B is fixed to the middle of the blade plate 310A, and the blade plate 310A has a blade plate upper portion 311 located on the upper surface side of the connecting plate 31B and a blade plate lower portion located on the lower surface side of the connecting plate 31B. It is divided into 312. The blade plate upper portion 311 has a function of scattering the water to be treated, which is pumped from the water passage hole 31D by the rotation of the impeller 31, around the impeller 31. The blade plate lower portion 312 is arranged in water and mainly forms a stirring flow in the water to be treated. Further, by arranging the tip of the blade plate lower portion 312 on the surface of the water to be treated, the water to be treated can be scattered around the impeller.

As shown in FIG. 3A, the blade plate 310B is inclined forward in the rotation direction, and guides the water to be treated attracted by the blade plate 310A to the outside in the radial direction along the blade plate 310A. By providing the blade plate 310B, the amount of water to be treated is increased and the oxygen supply efficiency can be further improved. The angle formed by the blade plate 310B and the blade plate 310A is, for example, preferably 100 to 170 °, and more preferably 110 to 160 °.

The materials of the blade plate 310A and the blade plate 310B are not particularly limited, and examples thereof include metal such as iron and stainless steel, and resin such as hard plastic. From the viewpoint of strength and corrosion resistance, corrosion-resistant metals such as stainless steel are preferable.

The shape of the blade portion 31A is not particularly limited. For example, in the first embodiment, the plate surface of the blade plate 310A is installed substantially parallel to the axial direction (substantially vertical direction), but the blade plate 310A is installed. The plate surface may be fixed at an angle with respect to the water surface. Further, the blade portion 31A may be formed only by the blade plate 310A without providing the blade plate 310B.

<Connecting board>
As shown in FIGS. 3A to 3C, the connecting plate 31B is fixed to the blade plate 310A via a gap between the connecting plate 31B and the shaft 31C, and the gap forms a water passage hole 31D through which the water to be treated passes. do.

The connecting plate 31B is formed of a plate member, and the material thereof is not particularly limited, and examples thereof include a metal such as iron and stainless steel, and a resin such as hard plastic. From the viewpoint of strength and corrosion resistance, corrosion-resistant metals such as stainless steel are preferable.

The shaft 31C, the blade portion 31A, and the connecting plate 31B may be connected as separate bodies or formed as an integral body.

In the impeller 31 of the first embodiment, as shown in FIG. 3D, the radial outer end 313 of the connecting plate 31B is the radial outer end of the blade portion 31A from the shaft 31C when viewed from the direction of the shaft 31C. It is arranged at a position (hatched portion) radially outside of 90% of the length (X) of the blade portion 31A having the total length up to the portion.
The end portion 313 of the connecting plate 31B may exceed 100% of the length (X) of the blade portion 31A (the end portion of the connecting plate is located outside the end portion of the blade portion 31A). , Preferably 100% or less.

Centrifugal force is applied to the water to be treated flowing from the water passage hole 31D when it flows on the upper surface of the connecting plate 31B, and the water is accelerated. The flow of water to be treated accelerated on the upper surface of the connecting plate 31B is vigorously scattered from the blade portion 31A. When the end portion 313 of the connecting plate 31B is arranged outside 90% of the length (X) of the blade portion 31A, a strong centrifugal force is applied, so that the flying distance of droplets increases. Therefore, the amount of oxygen taken into the droplets increases, which has the effect of improving the oxygen supply efficiency.
By optimizing the position of the end portion 313 of the connecting plate 31B, the water to be treated can be scattered farther than the conventional impeller, so that the water to be treated can be effectively aerated. It becomes.

(Guide plate)
The guide plate 7 is intended to agitate and circulate the water to be treated in the non-terminal water channel 2 by rectifying the stirring flow generated by the impeller 31 of the vertical axis type aeration stirring device 3.
As shown in FIG. 1, the guide plate 7 is fixed to the partition wall 22 so as to cover the upstream side of the vertical axis type aeration stirring device 3.
As shown in FIG. 2, the installation height of the guide plate is such that the upper end is located substantially on the surface of the water to be treated and the lower end is located at the same level as or slightly higher than the lower end of the vertical axis type aeration agitator. By locating the upper end of the guide plate substantially on the water surface, the droplets scattered by the rotation of the impeller 32 land on the surroundings, and the oxygen supply efficiency can be improved. In addition, it is excellent in the action of eliminating floating scum.
Further, by installing the lower end of the guide plate in the same manner as the lower end of the vertical axis type aeration stirring device, the stirring flow generated by the rotation of the impeller 32 can be guided to a predetermined position.

[Second embodiment]
4A to 4C are perspective views, plan views, and cross-sectional views showing the structure of the impeller 41 in the second embodiment, respectively.
Below, we will explain in detail using drawings. The blade portion 41A and the shaft 41C have the same contents as the blade portion 31A and the shaft 31C in the first embodiment, and thus the description thereof will be omitted.

<Connecting board>
In the impeller 41 of the second embodiment, as shown in FIG. 4D, the length (Y1) of the gap from the shaft 41C to the connecting plate 41B is the diameter of the connecting plate 41B from the shaft 41C when viewed from the direction of the shaft 41C. It is 40 to 70% of the length (Y2) up to the end 413 on the outer side of the direction.

Assuming that the length of the gap (Y1) from the shaft 41C to the connecting plate 41B is 40 to 70% of the length (Y2) from the shaft 41C to the radial outer end 413 of the connecting plate 41B, the water passage hole 41D A sufficient amount of water to be treated can be secured. Therefore, the amount of water to be treated is increased, and the oxygen supply efficiency is improved.
By optimizing the gap between the connecting plate 41B and the shaft 41C, more water to be treated can be scattered compared to the conventional impeller, so that the water to be treated can be effectively aerated. It becomes.

[Third Embodiment]
5A to 5C are perspective views, plan views, and cross-sectional views showing the structure of the impeller 51 in the third embodiment, respectively.
Below, we will explain in detail using drawings. The blade portion 51A and the shaft 51C have the same contents as the blade portion 31A and the shaft 31C in the first embodiment and the blade portion 41A and the shaft 41C in the second embodiment, and thus the description thereof will be omitted.

<Connecting board>
In the impeller 51 of the present embodiment, as shown in FIG. 5D, the end portion 513 of the connecting plate 51B is arranged at a position (hatched portion) radially outside of 90% of the length (X) of the blade portion 51A. .. Further, the length of the gap (Y1) from the shaft 51C to the connecting plate 51B is 40 to 70% of the length (Y2) from the shaft 51C to the radial outer end 513 of the connecting plate 51B. According to these characteristics, while sufficiently securing the amount of water to be treated that is pumped by the rotation of the impeller 51, centrifugal force is applied and accelerated when the water to be treated flows on the upper surface of the connecting plate 51B. It has the effect of increasing the flight distance of the droplets.
By optimizing the gap between the connecting plate 51B and the shaft 51C and the position of the end portion 513 of the connecting plate 51B, the conventional impeller, the impeller 31 of the first embodiment, and the impeller 41 of the second embodiment can be used. In comparison, it is possible to effectively aerate the water to be treated.
Further, according to these characteristics, it is possible to effectively increase the oxygen supply efficiency with even less power.

[Example 1]
The relationship between the power and the aeration amount of the impeller 31 of the first embodiment, the impeller 51 of the third embodiment, and the existing impeller 61 (FIGS. 6A to 6B) was compared by simulation.
In the simulation, the outer diameters of the impeller 31 of the first embodiment, the impeller 51 of the third embodiment, and the existing impeller 61 were made the same.
In the existing impeller 61, the position of the end of the connecting plate 61B is 85% of the length (X) of the blade portion 61A, and the length of the gap (Y1) from the shaft 61C to the connecting plate 61B is the connecting plate from the shaft 61C. It was set to 35% of the length (Y2) to the radial outer end of 61B.
In the impeller 31 of the first embodiment, the position of the end portion of the connecting plate 31B is set to 100% of the length (X) of the blade portion 31A, and the length of the gap (Y1) from the shaft 31C to the connecting plate 31B is the axis. The length (Y2) from 31C to the radial outer end of the connecting plate 31B was set to 35%.
In the impeller 51 of the third embodiment, the position of the end portion of the connecting plate 51B is set to 100% of the length (X) of the blade portion 51A, and the length of the gap (Y1) from the shaft 51C to the connecting plate 51B is the axis. The length (Y2) from 51C to the radial outer end of the connecting plate 51B was set to 55%.

The result of the simulation is shown in the graph of FIG. The horizontal axis of the graph is power, and the vertical axis is aeration. The amount of aeration was the amount of water droplets to be treated that passed through the predetermined area.

As shown in FIG. 7, when the power used for the rotation of each impeller was the same, the impeller 51 of the third embodiment had the highest aeration amount substitution index, followed by the impeller 31 of the first embodiment. The result was that the existing impeller 61 was the lowest.
Further, it was found that the impeller 51 of the third embodiment has the highest energy efficiency, the impeller 31 of the first embodiment has the highest energy efficiency, and the existing impeller 61 has the lowest energy efficiency when viewed with the same aeration amount. rice field.

[Example 2]
In Example 2, the relationship between the rotation speed of the impeller 51 of the third embodiment and the impeller of the existing impeller 61 and the oxygen supply efficiency was compared by simulation. Other conditions were the same as in Example 1.

The result of the simulation is shown in the graph of FIG. The horizontal axis of the graph is the rotation speed of the impeller, and the vertical axis is the oxygen supply efficiency. The oxygen supply efficiency is the amount of oxygen supplied to the water to be treated divided by the amount of power per unit time, and the higher the value, the more efficiently oxygen can be supplied with less power.

As shown in FIG. 8, when the rotation speed of each impeller is the same, the result is that the impeller 51 of the third embodiment has higher oxygen supply efficiency than the existing impeller 61.

The above-described embodiment shows an example of an impeller of an aeration agitator. The impeller according to the present invention is not limited to the above-described embodiment, and the impeller according to the above-described embodiment may be modified without changing the gist of the present invention.

For example, two blades and a connecting plate may be installed vertically on the same axis.
As a result, the impeller placed on the lower side can be completely submerged in the water to be treated to stir the water to be treated, and the impeller placed on the upper side can disperse the water to be treated into the atmosphere. The stirring power can be improved while maintaining the efficiency.

Further, the structure may be such that the angle of the blade plate with respect to the shaft and the angle of the blade plate or the connecting plate with respect to the shaft can be easily changed after the impeller is installed. In this case, the shape of the impeller can be easily changed in the field so as to exhibit the optimum aeration / stirring ability according to the viscosity of the water to be treated.

The impeller of the present invention can be suitably used for a vertical axis type aeration stirrer for biological water treatment equipment.

1 Biological treatment equipment, 2 Non-terminal waterway, 2a Straight waterway, 2b Circulation waterway, 21 Peripheral wall, 22 Section wall, 3 Vertical axis type aeration stirrer, 31,41,51,61 Impeller, 31A, 41A, 51A, 61A Blades, 31B, 41B, 51B, 61B Connecting plates, 31C, 41C, 51C, 61C shafts, 31D, 41D, 51D, 61D Water flow holes, 310A, 310B Blade plates, 311 Upper blade plates, 312 Lower blade plates, 313 , 413,513 Connecting plate end, 31E connecting part, 31F lifting device, 33 driving part, 7 guide plate, X blade length, Y1 gap length, Y2 connecting plate length to the end

Claims (3)

An impeller that aerates and / or stirs the water to be treated.
Axis and
A plurality of blades extending radially outward from the shaft,
A plurality of connecting plates arranged between two blades adjacent to each other in the circumferential direction and connecting the two blades are provided.
A gap is formed between the connecting plate and the shaft.
The radial outer end of the connecting plate is radially more than 90% of the length of the blade having the total length from the shaft to the radial outer end of the blade when viewed from the axial direction. An impeller characterized by being installed in an outer position. When viewed from the axial direction, the length of the gap from the shaft to the connecting plate is 40 to 70% of the length from the shaft to the radial outer end of the connecting plate. , Impeller. The impeller according to claim 1 or 2, wherein the blade portions are provided on both the upper surface side and the lower surface side of the connecting plate.

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