JP3887303B2 - Stirrer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stirrer that performs liquid-liquid system, solid-liquid system, or solid-liquid-gas system mixing, and more particularly to a stirring blade structure suitable for performing efficient mixing and reaction.
[0002]
[Prior art]
Conventionally, the blade shape used for stirring liquid-liquid systems, solid-liquid systems, and solid-liquid-gas systems is as shown in page 259 of Liquid Mixing Technology (Nikkan Kogyo; 1989) (Prior Art 1). Disc turbine blades, paddle blades and propellers having a plurality of blades are known. Alternatively, there is a grid-like stirring blade as disclosed in Japanese Patent Laid-Open No. 06-312122 (prior art 2).
[0003]
[Non-Patent Document 1]
Liquid mixing technology (Nikkan Kogyo; 1989) (see page 259)
[Patent Document 1]
Japanese Patent Application Laid-Open No. 06-312122
[Problems to be solved by the invention]
However, the prior arts 1 and 2 do not give sufficient consideration to the suspension and dispersibility of solid particles.
[0005]
The object of the present invention is to solve the above-mentioned problems of the prior art by improving the mixing of liquid and solid particles with a wing having a relatively simple structure, and by dispersing the solid particles more uniformly than in the past. Increase the contact area of the liquid to increase the reaction between the solid particles and the liquid or the solubility of the solid particles in the liquid, improve the mixing in the solid-liquid system or the solid-liquid-gas system, and perform the reaction efficiently It is providing the stirring apparatus which can be performed.
[0006]
Another object of the present invention is to provide a stirrer capable of effectively mixing in a liquid-liquid system in a shorter mixing time than in the past, and in which the mixing performance does not deteriorate to a certain high viscosity range. is there.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is provided outside the stirring tank as a stirring blade used for stirring a liquid-liquid system, a solid-liquid system, or a solid-liquid-gas system in the stirring tank. An angle is given between the first paddle blade close to the bottom of the tank attached to the rotating shaft that is rotationally connected to the rotation drive source, and the first paddle blade on the top of the first paddle blade. A first paddle blade connecting the outer peripheral ends of the first and second paddle blades with a second paddle blade having an outer diameter smaller than the outer diameter of the first paddle blade attached to the rotating shaft. And a second auxiliary blade, and further the shape of the lower end of the first paddle blade of the stirring blade is approximated to the shape of the bottom of the stirring tank .
[0008]
In the stirring blade of the stirring device , for example, the shape in the axial plane of the first paddle blade may be a polygon such as an approximate hexagonal shape.
According to the present invention, in the stirring blade of the stirring device, the first paddle blade, the first auxiliary blade, the second paddle blade, and the second auxiliary blade are integrally formed in a plate shape. It is formed.
[0009]
In the stirring blade of the stirring device, the blade diameter (outer diameter) of the first paddle blade may be in the range of about 1/2 to about 3/4 of the inner diameter of the stirring tank. The blade height of one paddle blade is about 1/4 or less of the inner diameter of the stirring tank, and the blade diameter (outer diameter) of the second paddle blade is about 3/10 to 5/5 of the inner diameter of the stirring tank. The blade height of the second paddle blade is in the range of about 1/15 to about 1/10 of the inner diameter of the stirring tank.
The present invention is also characterized in that, in the stirring blade of the stirring device, the blade width of the first and second auxiliary blades is in the range of about 1/10 to about 2/10 of the inner diameter of the stirring tank. To do.
[0010]
Further, the present invention is characterized in that, in the stirring blade of the stirring device, the certain angle between the first paddle blade and the second paddle blade is in a range of about 10 ° to about 45 °. To do.
Further, the present invention is characterized in that, in the stirring blade of the stirring device, the first paddle blade is advanced (preceded) by a certain angle in the rotational direction than the second paddle blade.
In the stirring tank of the stirring device, the present invention is characterized in that a plurality of baffle plates extending in the axial direction are arranged in parallel on the inner periphery.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a stirrer (referred to as a stirrer, a mixer or a reactor) that stir and mix a liquid-liquid system, solid-liquid system, or solid-liquid-gas system according to the present invention will be described with reference to the drawings. .
[0012]
FIG. 1 to FIG. 3 are drawings when the first embodiment of the stirring blade is used in the stirring device according to the present invention.
[0013]
As shown in FIG. 3, the embodiment of the stirrer (stirrer, mixer or reactor) according to the present invention comprises a stirring blade 5 that is rotated by a shaft 1 in a stirring tank 6. The shaft 1 is supported so as to be rotatable, is connected to a rotational drive source (not shown), and is rotationally driven by the rotational drive source.
[0014]
FIG. 1 is a front view showing the stirring blade 5 of the first embodiment. FIG. 2 is a view of the stirring blade 5 of the first embodiment disposed in the stirring tank 6 as viewed from the axial direction.
[0015]
The agitating blade 5 includes a first paddle blade 2 attached to a shaft (rotating shaft) 1 and a second paddle blade 3 having a smaller blade diameter than the first paddle blade 2 provided on the shaft 1. The first paddle blade 2 and the second paddle blade 3, and first and second auxiliary blades 4 connected to each other, and the first paddle blade 2 and the second paddle blade 2 are connected to each other. The two paddle blades 3 are arranged with a certain angle θ with respect to the shaft 1, and the axial cross-sectional shape of the shaft 1 of the first paddle blade 2 is configured to be an approximate hexagonal shape. . The approximate hexagonal shape has a horizontal side at the lower end matched to the elliptical shape at the bottom of the stirring tank 6, two inclined sides connected to each of both sides thereof, two vertical sides at the outer peripheral ends, and It is formed with a horizontal side. That is, the approximate hexagonal shape is obtained by connecting an approximate trapezoidal shape to an approximate rectangular shape on the lower side. In particular, the approximate hexagonal shape is that at the lower end, a shape approximated to the elliptical shape of the bottom of the stirring vessel 6, that is, a horizontal side and sides inclined on both sides thereof are provided. The first paddle blade 2 and the second paddle blade 3 are attached to the shaft 1 with a deviation of an angle θ. In the first embodiment, the first paddle blade 2 is positioned ahead of the second paddle blade 3 in the rotational direction. Therefore, the third and fourth auxiliary blades 4 have an effect of giving a flow velocity component that raises the fluid in the stirring tank 6 in the liquid surface direction by rotating.
[0016]
By the way, the first paddle blade 2, the second paddle blade 3, the first and second auxiliary blades 4 are plate-like except for a portion fixed to the shaft 1, as shown in FIG. Since it is integrally formed with a material, a simple structure can be achieved. The first paddle blade 2 and the second paddle blade 3 need to be fixed to the shaft (rotary shaft) 1, and therefore this portion does not have to be plate-shaped, but the shaft (rotary shaft). It may be fixed to 1.
[0017]
Next, a basic liquid flow will be described with reference to FIG. The stirring tank 6 is provided with a fluid 8 and a stirring blade 5. By appropriately rotating the shaft 1, the fluid discharged from the relatively large first paddle blade 2 provided at the bottom of the tank circulates to the upper part of the stirring tank as indicated by an arrow while turning in the radial direction. While the swirl component is given by the second paddle blade 3, the trapezoidal hollow portion 9 without the blade is lowered and returned to the first paddle blade 2 again to be discharged. On the other hand, a part of the fluid discharged from the first paddle blade 2 is sucked from the bottom of the first paddle blade 2 along the bottom of the stirring tank 6. In particular, the first and second auxiliary blades 4 are effective for smoothly raising and circulating the fluid in the liquid surface direction when the viscosity of the fluid is high or the rotation speed is low (laminar flow). Demonstrate.
[0018]
Further, the geometric shape of the first embodiment of the stirring blade will be described in detail with reference to FIG. In order to discharge the fluid from the first paddle blade 2 while swirling in the radial direction as shown in FIG. 3, the outer diameter (blade diameter) d1 of the first paddle blade 2 is ½ of the inner diameter of the stirring tank 6. It is preferable that the blade height (height dimension) h1 of the first paddle blade 2 is about 1/4 or less of the inner diameter of the stirring tank 6 as a stirring blade. . In order to swirl and lower the fluid from the second paddle blade 3, the outer diameter (blade diameter) d2 of the second paddle blade 3 is in the range of about 3/10 to about 5/10 of the inner diameter of the stirring tank 6. Desirably, the blade height (height dimension) h2 of the second paddle blade 3 is in the range of about 1/15 to about 1/10 of the tank inner diameter as the stirring blade. Further, the blade width d3 of the first and second auxiliary blades 4 is preferably in the range of about 1/10 to about 2/10 of the inner diameter of the stirring tank 6. Also, it is desirable that the angle deviation θ between the first paddle blade 2 and the second paddle blade 3 shown in FIG. 2 is in the range of about 10 ° to about 45 °. This θ needs to be increased as the viscosity of the fluid increases in order to perform smooth mixing.
In addition, a plurality of baffle plates (not shown) extending in the axial direction of the rotating shaft 1 may be arranged in parallel at predetermined intervals in the circumferential direction on the inner periphery of the stirring tank 6.
[0019]
Next, the stirring blade 5 'of the second embodiment according to the present invention will be described with reference to FIG.
[0020]
The agitating blade 5 ′ is different from the first embodiment in that the cross-sectional shape of the first paddle blade 2 ′ is an approximate rectangular shape (approximate rectangular shape). In the case of the stirring blade 5 ', there is no problem in mixing when the bottom shape of the stirring tank 6 is flat, but in the case of a general industrial reactor, the shape of the tank bottom is an ellipse. When a quadrangular shape (rectangular shape) is adopted for the paddle blade, the gap between the tank bottom and the lower end of the second paddle blade becomes large, which is disadvantageous for mixing in the case where the solid is suspended.
[0021]
Next, a stirring device in the solid-liquid stirring tank 6 provided with the stirring blade 5 of the first embodiment will be described with reference to FIG. The inner diameter of the stirring tank 6 is about 1.44 m, the distance from the tank bottom to the liquid surface is about 1.38 m, and the capacity is about 2.4 m ³ . The rotation speed of the stirring blade 5 is about 0.5 to 0.83 s ⁻¹ , the blade diameter (outer diameter) of the first paddle blade 2 is about 0.776 m, and the blade diameter (outer diameter) of the second paddle blade 4. Is about 0.6 m, the blade width of the first and second auxiliary blades 4 is about 0.144 m, the blade height of the first paddle blade 2 is about 0.259 m, and the blade height of the second paddle blade 3 Is about 0.144 m, and the angle shift θ between the first paddle blade 2 and the second paddle blade 3 is about 30 °.
[0022]
By the way, the calculation conditions for analyzing the floating state of the solid particles exist in the tank in a state where the particle average diameter is about 1 mm, the particle specific gravity is about 1.25, and the volume fraction of the particles is about 0.4. Under the conditions, the liquid used physical properties of water at room temperature. General-purpose software (three-dimensional flow analysis; finite difference method, k-ε model) is used for the analysis.
[0023]
FIG. 6 shows a case where the stirring blade 5 of the first embodiment is provided in the solid-liquid stirring tank 6 shown in FIG. 5 and a case where the stirring blade 5 ′ of the second embodiment is provided. An analysis result is shown. The horizontal axis represents the number of revolutions of the stirring blade, and the vertical axis represents the non-dimensionalization by dividing the standard deviation of the concentration of solid particles in the stirring tank by the average concentration (= 0.4). Therefore, the smaller this value, the more uniformly the solid particles are dispersed in the tank. Black ● 20 represents the calculated value of the standard deviation of the particles in the tank using the stirring blade 5 of the first embodiment, and black ▲ 21 represents the stirring blade 5 ′ of the second embodiment. From the figure, it can be seen that the standard deviation in the tank abruptly decreases as the rotational speed increases, and the solid particles are made uniform. On the other hand, ▲ 21 shows that the standard deviation of the concentration is large at the same rotation speed, that is, the dispersion state of the solid particles in the tank is poor. Therefore, it can be seen that the use of the stirring blade of the first embodiment to reduce the gap between the tank bottom and the blade provides an advantageous design for the suspension of solid particles. Moreover, the stirring power of each (stirring blade 5 of 1st Example and stirring blade 5 'of 2nd Example) is substantially the same at the same rotation speed.
[0024]
As described above, according to the present embodiment, the solid-liquid contact area for further improving the mass transfer from the solid particles to the liquid when applied to the reactor to improve the mixing of the solid particles and the liquid. This has the effect of promoting an increase in the amount of water and, in turn, the effect of enabling an efficient reaction. Furthermore, there is an effect that the mixing can be completed in a shorter time than a conventional blade (turbine blade, paddle blade, etc.) even in a relatively high viscosity region. In particular, when the tank bottom is elliptical as a stirring tank, the use of the first embodiment as a stirring blade reduces the gap between the tank bottom and the blade to make the solid particles uniform. It becomes possible to improve the mixing of the liquid.
[0025]
【The invention's effect】
According to the present invention, compared with a conventional blade, with the same stirring power, the floating of solid particles is facilitated, the mixing of solid particles and liquid is made better, and when applied to a reactor, the substance from solid particles to liquid There is an effect of promoting an increase in the contact area of the solid-liquid to further increase the movement, and as a result, there is an effect that an efficient reaction can be performed.
[0026]
Further, according to the present invention, when applied to a liquid-liquid reactor, the mixing time is shorter than that of a conventional blade, so that the reaction time can be shortened and the product quality can be improved. Furthermore, since mixing can be completed earlier than in the conventional blade even in a relatively high viscosity region, there is an effect that the reaction can be performed efficiently, and the reaction time can be shortened and the quality of the product can be improved.
[0027]
In addition, according to the present invention, even when applied to a flow reactor that requires a certain amount of residence time, there is an effect that a complete mixing tank can be achieved from a low viscosity to a certain high viscosity range.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a first embodiment of a stirring blade according to the present invention.
FIG. 2 is a view of the stirring blade according to the first embodiment of the present invention as viewed from the axial direction of the stirring blade.
FIG. 3 is a schematic cross-sectional view showing the flow of fluid in a stirring tank using the first embodiment of the stirring blade according to the present invention.
FIG. 4 is a schematic cross-sectional view illustrating a second embodiment of the stirring blade according to the present invention.
FIG. 5 is a schematic cross-sectional view of a stirring device using a first embodiment of a stirring blade according to the present invention.
FIG. 6 shows the relationship between the standard deviation of the concentration of solid particles in the stirring vessel and the rotational speed of the stirring blade, which is the analysis result when the first and second embodiments of the stirring blade according to the present invention are used. FIG.
[Explanation of symbols]
2... First hexagonal paddle blade, 2 ′. First square paddle blade of approximate quadrangle shape, 3. Second paddle blade, 4... First and second auxiliary blades 5. 5 '... stirring blade, 6 ... stirring tank, 8 ... fluid,
20: Standard deviation of solid particles in the tank with respect to the average concentration at the stirring blade of the first example, 21 ... Standard deviation of solid particles in the tank with respect to the average concentration at the stirring blade of the second example.

Claims (7)

A stirring tank,
Provide a rotation drive source provided outside the stirring tank,
An angle is given between the first paddle blade close to the bottom of the tank attached to the rotating shaft that is rotationally connected to the rotational drive source and the first paddle blade on the top of the first paddle blade. A first paddle blade connecting the outer peripheral ends of the first paddle blade and the second paddle blade having an outer diameter smaller than the outer diameter of the first paddle blade attached to the rotary shaft. A stirring blade configured by providing a second auxiliary blade is provided in the stirring tank,
Furthermore, the stirring device is characterized in that the shape of the lower end of the first paddle blade of the stirring blade is approximated to the shape of the bottom of the stirring tank.   The stirring device according to claim 1, wherein the shape of the first paddle blade in the axial direction is an approximate hexagonal shape.   2. The stirring device according to claim 1, wherein a blade diameter of the first paddle blade is in a range of ½ to 3/4 of an inner diameter of the stirring tank, and a blade height of the first paddle blade is the stirring blade. The inner diameter of the tank is equal to or less than 1/4, the blade diameter of the second paddle blade is in the range of 3/10 to 5/10 of the inner diameter of the stirring tank, and the blade height of the second paddle blade is A stirrer characterized by being in the range of 1/15 to 1/10 of the inner diameter of the stirrer.   4. The stirring device according to claim 1, wherein the first and second auxiliary blades have a blade width in a range of 1/10 to 2/10 of an inner diameter of the stirring tank. .   5. The stirring device according to claim 1, wherein the certain angle between the first paddle blade and the second paddle blade is in a range of 10 ° to 45 °. A stirrer.   2. The stirring device according to claim 1, wherein the first paddle blade is advanced by a certain angle in the rotation direction with respect to the second paddle blade. 3. 2. The stirring apparatus according to claim 1, wherein a plurality of baffle plates are arranged side by side on the inner periphery of the stirring tank .

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