JP2019209240A - Stirring method and stirring device - Google Patents

Abstract

To provide a stirring method and a stirring device which can improve uniform mixing performance while maintaining shearing force.SOLUTION: In a stirring method in which an object 50 to be stirred stored in a stirring tank 10 is stirred using a stirring device 1 equipped with a cylindrical stirring tank 10, a rotating shaft 11 arranged along a center shaft of the stirring tank 10 and a plurality of stirring vanes 20 attached to the rotating shaft 11, the stirring vanes 20 are all stirring vanes having radial-directional flow and attached in three tiers at intervals in a shaft direction Z of the rotating shaft 11, where the rotating shaft 11 is rotated to stir the object 50 to be stirred under the condition that a ratio of a distance h2 between the stirring vane 20d in a lower tier and the stirring vane 20m in a middle tier to a distance h3 between the stirring vane 20u in the upper tier and the stirring vane 20m in the middle tier is set to be 0.50 and more and 0.95 or less, and a ratio of a distance h1 between the stirring vane 20d in the lower tier and a tank bottom 10a of the stirring tank to a height H from the tank bottom 10a of the stirring tank to an upper end 50a of the object to be stirred is set to be 0.190 or more and 0.345 or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a stirring method and a stirring device.

  A radial flow type stirring blade such as a disk turbine blade or a flat paddle blade has a characteristic that a large shear stress is obtained, and a discharge flow from the blade is directed in a radial direction of the stirring tank. On the other hand, since it is difficult to form an axial flow of the stirring tank and the flow in the tank is easily divided vertically, there is a problem that the uniform mixing property of the entire tank is low.

  Various techniques for improving uniform mixing in the tank have been developed. For example, in the techniques disclosed in Patent Documents 1 and 2, a vertical circulation flow can be formed by combining a radial flow type stirring blade and an axial flow type stirring blade. Moreover, in the technique disclosed in Patent Document 3, the upper and lower circulation flows can be formed by designing the blade area of the stirring blade to increase toward the lower part of the tank.

Japanese Patent No. 5921433 Japanese Patent Laying-Open No. 2015-054272 JP 2006-87998 A

  However, in the techniques of Patent Documents 1 and 2, the axial flow type stirring blade forms a vertically circulating flow in the entire tank by a large discharge flow in the axial direction, but the obtained shearing force is small. Therefore, uniform mixing can be improved by using an axial flow type stirring blade, but there is a problem that the shear stress that should be obtained by the radial flow type stirring blade is reduced. Further, the technique of Patent Document 3 has a problem that since the blade area is large, a very large amount of power is consumed, and the obtained shear stress becomes excessively large.

In general, when using a three-stage stirring blade, the lower blade is disposed as close to the bottom of the tank as possible, and the upper blade is disposed at a certain distance from the liquid surface so as not to disturb the liquid surface. Furthermore, the middle blade is arranged at the center of the upper blade and the lower blade so that the distance between the stirring blades is uniform. In the case of this normal arrangement, the radial discharge flow generated by each stirring blade has been thought to flow independently until now, but the present inventors conducted various studies on the flow state in the tank. As shown in FIG. 7B, it was found that the discharge flow generated by the lower blades turned downward toward the bottom of the tank, and the discharge flow generated by the upper two stirring blades joined the flow pattern. In addition, the discharge flow generated by the two-stage agitating blades is well mixed because it joins before colliding with the wall of the agitation tank or the baffle plate and separating in the vertical direction. However, since the circulation flow by the discharge flow generated by the lower stirring blades is generated separately from the discharge flow generated by the upper two stirring blades, it is difficult for the liquid composition above to move to the lower part of the tank. Therefore, when the inside of the tank is stirred as the arrangement of the normal stirring blade as described above, the uniform mixing property of the entire tank is lowered.
The radial flow type stirring blade has a large shearing force, and is often used for processes that require shearing force such as gas-liquid reaction, emulsification, solid-liquid dispersion, etc. In the above-mentioned process, the uniformity of the final product, Uniform mixing is also important from the viewpoint of product quality. However, if the inside of the tank is agitated with the above-described arrangement of the stirring blades and the uniform mixing property of the whole tank is low, inconveniences such as deterioration in product quality are likely to occur.
Here, when the number of rotations is increased in order to improve the uniform mixing property, the shearing force obtained is also increased. However, in the case of a gas-liquid reaction process, when the shear force is increased, the gas mass transfer coefficient is increased, so that the reaction time is shortened and the yield and quality of the product may be lowered. Also in the emulsification and solid-liquid dispersion processes, the droplet diameter (particle diameter) decreases due to an increase in shearing force, so that desired physical properties cannot be obtained and the product quality may be degraded. Therefore, there is a demand for an agitation method that imparts a shearing force that conforms to product specifications and at the same time has high uniform mixing properties.

  The subject of this invention is providing the stirring method and stirring apparatus which can solve the subject which the prior art mentioned above has.

  The present invention uses a stirrer provided with a cylindrical stirring tank, a rotating shaft arranged along the central axis of the stirring tank, and a plurality of stirring blades attached to the rotating shaft. A stirring method for stirring a liquid to-be-stirred object accommodated in a tank, wherein each of the stirring blades is a radial flow type stirring blade, and has three stages at intervals in the axial direction of the rotating shaft. A distance h2 between the agitating blades attached to the lower stage and the agitating blades located in the middle stage, and a distance h3 between the agitating blade located in the upper stage and the agitating blades located in the middle stage. (H2 / h3) is 0.50 or more and 0.95 or less, and the distance h1 between the stirring blade located in the lower stage and the tank bottom of the stirring tank, and the tank bottom of the stirring tank Conditions where the ratio (h1 / H) to the height H to the upper end of the object to be stirred is 0.20 or more and 0.30 or less , Said rotary shaft is rotated, the there is provided a stirring method for stirring the object to be agitated thereof.

  Further, the present invention is a stirring device comprising a cylindrical stirring tank, a rotating shaft disposed along the central axis of the stirring tank, and a plurality of stirring blades attached to the rotating shaft, A baffle plate is attached to the inner peripheral surface of the stirring tank, and each of the stirring blades is a radial flow type stirring blade, and is attached in three stages at intervals in the axial direction of the rotating shaft, A ratio (h2) between a distance h2 between the stirring blade located in the lower stage and the stirring blade located in the middle stage and a distance h3 between the stirring blade located in the upper stage and the stirring blade located in the middle stage / H3) is 0.50 or more and 0.95 or less, and the ratio (h1 /) between the distance h1 between the stirring blade located in the lower stage and the tank bottom of the stirring tank and the inner diameter D of the stirring tank The stirring apparatus in which D) is 0.190 or more and 0.345 or less is provided.

  According to the stirring method and the stirring device of the present invention, the uniform mixing property can be improved while maintaining the shearing force by the radial flow type stirring blade.

FIG. 1 is a schematic cross-sectional view of a stirring device according to an embodiment of the stirring method and the stirring device of the present invention. FIG. 2 is a cross-sectional view orthogonal to the rotation axis in the stirring apparatus shown in FIG. 1, and is a common cross-sectional view taken along lines Ia-Ia, Ib-Ib, and Ic-Ic in FIG. FIG. 3 is a perspective view of a stirring blade included in the stirring device shown in FIG. 1. 4A is a side view of the stirring blade shown in FIG. 3, and FIG. 4B is a diagram for explaining the inclination angle of the blade of the stirring blade. FIG. 5 is a diagram illustrating a flow pattern generated in the stirring tank when the stirring method according to the embodiment of the present invention is used. 6 (a), 6 (b) and 6 (c) are diagrams for explaining the shape of a baffle plate of a stirring device according to another embodiment of the present invention. 7 (a), 7 (b), 7 (c), and 7 (d) are diagrams for explaining the flow pattern generated in the stirring tank when the stirring methods of the examples and comparative examples are used. is there. FIG. 8A is a diagram showing a trajectory line in the stirring tank when stirred by the stirring method of Example 1, and FIG. 8B is the inside of the stirring tank when stirred by the stirring method of Comparative Example 1. FIG. FIG. 9 is a diagram showing changes over time in separation strength when stirring is performed by the stirring method of Example 1 and Comparative Example 1. FIG. FIG. 10 is a diagram illustrating a torque 5-section moving average when stirring is performed by the stirring method of Example 1 and Comparative Example 1. FIG. 11 is a diagram showing a torque 5-section moving average when stirring is performed by the stirring methods of Example 1 and Comparative Example 11.

Hereinafter, the present invention will be described based on preferred embodiments thereof.
First, a stirring device used in a preferred embodiment of the stirring method of the present invention will be described. As shown in FIGS. 1 and 2, the stirring device 1 used in one embodiment of the stirring method of the present invention includes a cylindrical stirring tank 10 and a rotating shaft 11 disposed along the central axis of the stirring tank 10. And a plurality of stirring blades 20 attached to the rotating shaft 11 and a baffle plate 30 attached to the inner peripheral surface of the stirring tank 10.

  As shown in FIGS. 1 and 2, the stirring tank 10 is cylindrical and has a tank bottom 10a. The shape of the tank bottom 10a can be the shape of the tank bottom of the general stirring tank 10, and is not particularly limited, and examples thereof include a flat type, a 10% dish type, a semi-elliptical type, and a conical type. The shape of the tank bottom 10a is preferably a 10% dish type from the viewpoint of extracting the processed material and preventing the stay of the discharge flow at the tank bottom.

  As shown in FIGS. 1 and 2, the rotation shaft 11 is attached such that its central axis is located at the same position as the central axis of the stirring tank 10. The rotating shaft 11 is connected to a driving device (not shown) whose upper end is positioned above the stirring tank 10 and is rotatable.

  The stirring blade 20 is a radial flow type stirring blade. The “radial flow type stirring blade” refers to a stirring blade that generates a flow that flows substantially perpendicular to the rotating shaft in a direction away from the rotating shaft when the rotating shaft to which the stirring blade is attached is rotated. It is. That is, the radial flow type stirring blade generates a discharge flow in the radial direction of the stirring tank. Examples of the radial flow type stirring blade include a disk turbine blade, a paddle blade, a disper blade, and the like. Among them, stirring is possible at a relatively high speed, and a large shearing force is applied to the object 50 to be stirred. Therefore, it is preferable to use a disc turbine blade.

  As shown in FIG. 1, the stirring blade 20 is attached to the rotary shaft 11 in three stages at intervals in the axial direction Z. That is, the stirring device 1 includes, as the stirring blade 20, the stirring blade 20u located in the upper stage, the stirring blade 20m located in the middle stage, and the stirring blade 20d located in the lower stage. The stirring blade 20u located in the upper stage, the stirring blade 20m located in the middle stage, and the stirring blade 20d located in the lower stage have the same configuration except that the positions attached to the rotary shaft 11 are different. The three-stage stirring blades 20u, 20m, and 20d are attached to the rotating shaft 11 so that the distances between the stirring blades 20u, 20m, and 20d in the axial direction Z of the rotating shaft 11 are not uniform.

In the stirring apparatus 1, as shown in FIG. 1, the distance h2 between the stirring blade 20d located in the lower stage and the stirring blade 20m located in the middle stage is equal to the stirring blade 20u located in the upper stage and the stirring blade 20m located in the middle stage. The distance h3 is smaller than the distance h3.
The distance h <b> 2 and the distance h <b> 3 are distances between the midpoints M of the stirring blades 20 adjacent in the axial direction Z of the rotating shaft 11. The position of the middle point M of each stirring blade 20 is a position that bisects the distance between the upper end and the lower end of the blade 22 in the axial direction Z of the stirring blade 20, and therefore the distance h2 is located in the lower stage. The distance between the middle point Md of the stirring blade 20d and the middle point Mm of the stirring blade 20m located in the middle stage, and the distance h3 is the middle point Mu of the stirring blade 20u located in the upper stage and the stirring blade 20m located in the middle stage. Is the distance from the midpoint Mm. A distance h1 and a distance h4 described later are also a distance between the middle point Md of the stirring blade 20d and the tank bottom 10a, and a distance between the middle point Mu of the stirring blade 20u and the upper end 50a of the object 50 to be stirred. In addition, when the stirrer blade 20 of a single stage has a plurality of blades 22 and the positions of the midpoints M of the blades 22 in the axial direction Z are different, the average position of the midpoints M in the axial direction Z is determined as the stirrer blades 20. Is the position of the midpoint M of the axial direction Z.

  A ratio of a distance h2 between the lower stirring blade 20d and the middle stirring blade 20m to a distance h3 between the upper stirring blade 20u and the middle stirring blade 20m (h2 / h3), the discharge flow generated by the stirring blades 20u located in the upper stage is isolated, the discharge flows generated by the stirring blades 20m and 20d positioned in the middle stage and the lower stage are merged toward the tank bottom, and the inside of the tank is divided into two From the viewpoint of preventing the mixability from decreasing, it is preferably 0.50 or more, more preferably 0.70 or more, still more preferably 0.76 or more, and The discharge flow generated by the agitating blade 20d positioned toward the bottom of the tank, the discharge flow generated by the agitating blades 20u and 20m positioned in the upper stage and the middle stage merge, the inside of the tank is divided into two, and the mixing property is reduced From the viewpoint of preventing, preferably 0.95 or less, more preferably 0.90 or less, further preferably 0.87 or less. Specifically, the ratio (h2 / h3) between the distance h2 and the distance h3 is preferably 0.50 or more and 0.95 or less, more preferably 0.70 or more and 0.90 or less, and 0 More preferably, it is not less than .76 and not more than 0.87.

  Further, the stirring blade 20d located in the lower stage has a certain distance h1 from the tank bottom 10a of the stirring tank 10. The distance h1 between the stirring blade 20d located in the lower stage and the tank bottom 10a of the stirring tank 10 is the distance between the midpoint Md of the stirring blade 20d located in the lower stage and the lower end of the inner surface of the tank bottom 10a of the stirring tank 10 Means. When a drain outlet, a manhole, a gas supply pipe 42, or the like is installed on the tank bottom 10a, the virtual lower end when assuming the shape of the inner surface of the tank bottom 10a without them is used as the lower end of the inner surface of the tank bottom 10a. And

  The ratio (h1 / D) between the distance h1 between the stirring blade 20d located in the lower stage and the tank bottom 10a of the stirring tank 10 and the inner diameter D of the stirring tank 10 is the discharge flow generated by the stirring blade 20d located in the lower stage. To the tank bottom 10a and only the discharge flow generated by the stirring blades 20u and 20m located in the upper and middle stages is merged, or only the discharge flow generated by the stirring blades 20m and 20d located in the middle and lower stages is merged From the viewpoint of preventing the mixing tank 10 from being divided into two parts and lowering the mixing performance, it is preferably 0.190 or more, more preferably 0.200 or more, and 0.210 or more. More preferably, even if the respective discharge flows generated by the three-stage stirring blades 20u, 20m, and 20d merge, the combined flow does not reach the lower part of the stirring tank 10, From the viewpoint of preventing the engagement performance is deteriorated, preferably at 0.345 or less, more preferably 0.322 or less, still more preferably 0.300 or less. Specifically, the ratio (h1 / D) between the distance h1 and the inner diameter D is preferably 0.190 or more and 0.345 or less, more preferably 0.200 or more and 0.322 or less, and 0 More preferably, it is 210 or more and 0.300 or less.

  In the present embodiment, the stirring blade 20 is a disk turbine blade including a disk 21 and blades 22 attached to the disk 21, as shown in FIG. The stirring blade 20 has six identical blades 22. The blades 22 have a plate shape and have a pair of stirring surfaces 23 parallel to each other. The stirring surface 23 intersects with the rotation direction of the stirring blade 20. The blade 22 of the stirring blade 20 is configured so that the stirring surface 23 of the blade 22 is the axis of the rotation shaft 11 from the viewpoint of generating a discharge flow in the radial direction of the stirring tank when the rotation shaft 11 to which the stirring blade 20 is attached is rotated. Although preferably provided so as to be substantially parallel to the imaginary line L parallel to the direction Z (see FIGS. 3 and 4A), the stirring surface 23 of the blade 22 is directed to the imaginary line L. It may be inclined. Specifically, the angle θ formed by the stirring surface 23 of the blade 22 and the phantom line L causes a discharge flow in the radial direction of the stirring tank 10 when the rotating shaft 11 to which the stirring blade 20 is attached is rotated. From the viewpoint, it is preferably 0 ° or more and 30 ° or less, and more preferably 0 ° or more and 20 ° or less (see FIG. 4B).

  The number of blades 22 included in the stirring blade 20 is not particularly limited, but is preferably 2 or more and 10 or less, more preferably 4 or more and 8 or less, and further preferably 5 or more and 7 or less. Less than The arrangement of the blades 22 in the stirring blade 20 is not particularly limited, but a plurality of blades are preferably formed at equal intervals in the circumferential direction, and are arranged point-symmetrically around the rotation shaft 11. Preferably it is.

  The ratio (d / D) between the outer diameter d of the stirring blade and the inner diameter D of the stirring vessel is not particularly limited, but if d / D is too large, the distance from the peripheral edge of the stirring blade to the wall surface is small. Thus, the discharge flow from the three-stage stirring blades reaches the wall surface before joining. On the other hand, if d / D is too small, the distance from the peripheral edge of the stirring blade to the wall surface becomes large, and uniform mixing in the radial direction cannot be maintained. Therefore, the ratio (d / D) between the outer diameter d of the stirring blade and the inner diameter D of the stirring tank is a general design value of 0.25 to 0.50, preferably 0.30 to 0.40. More preferably, it is desired to be 0.32 or more and 0.35 or less (see FIGS. 1 and 2). The outer diameter d of the stirring blade 20 means the diameter of a virtual circle R that passes through the radially outer end of each blade 22 of the stirring blade 20 (see FIG. 2).

  The length c in the radial direction of the stirring surface 23 of the blade 22 is not particularly limited. However, if the length c is too small, the discharge flow becomes small. The ratio (c / d) to the diameter d is preferably 0.10 or more and 0.50 or less, and more preferably 0.20 or more and 0.50 or less (see FIGS. 1 and 2).

  The height b of the stirring blade 20 is not particularly limited, but if the height b is too small, the discharge flow becomes small. Therefore, the ratio (b / d) to the outer diameter d of the stirring blade is generally The typical design value is preferably 0.15 or more and 0.25 or less, and more preferably 0.18 or more and 0.23 (see FIGS. 1 and 4). The height b of the stirring blade 20 means the height from the upper end to the lower end of the blade 22 of the stirring blade 20 in the axial direction Z (see FIGS. 1 and 4). When the blade 22 is provided so that the stirring surface 23 of the blade 22 is parallel to the virtual line L parallel to the axial direction Z of the rotating shaft 11, the height b of the stirring blade 20 is It coincides with the length e in the direction orthogonal to the radial direction (see FIG. 4A). When the stirring surface 23 of the blade 22 is inclined with respect to the imaginary line L, the height b of the stirring blade 20 coincides with the length e multiplied by cоsθ (see FIG. 4B).

  The ratio (c / b) between the length c in the radial direction of the stirring surface 23 of the blade 22 and the height b of the stirring blade 20 is 0.4 to 3.4, which is a general design value. Preferably, it is 1.0 or more and 2.5 or less (see FIG. 1).

  The projected area of the stirring surface 23 of the blade 22 of the stirring blade 20 on the surface parallel to the axial direction Z of the stirring tank 10 does not have to be the same, but if the projected area is too large, the discharge flow from the stirring blade 20 May be faster and the flow pattern may change. Moreover, the power required for stirring increases as the projected area increases. Therefore, among the blades 22u, 22m, and 22d of the three-stage stirring blades 20u, 20m, and 20d, when the projected area of the largest projected area is A1, and the projected area of the smallest projected area is A2, A1 The ratio of A2 to A2 (A1 / A2) is preferably 1.0 or more and 1.1 or less. In addition, the projection area to the surface parallel to the axial direction Z of the stirring tank 10 in the stirring surface 23 of the blade | wing 22 is calculated as follows.

<Calculation method of projected area on plane parallel to axial direction of stirring tank on stirring face of blade>
The projected area A of the stirring surface 23 of the blade 22 of the stirring blade 20 onto the surface parallel to the axial direction Z of the stirring tank 10 can be obtained by the following formula 1.
Projected area A = height of stirring blade b × length c of blade stirring surface in radial direction (Equation 1)

  As shown in FIG. 1, the stirring tank 10 includes a baffle plate 30. The shape of the baffle plate 30 is not particularly limited, but is preferably a general plate-like baffle plate. The ratio (s1 / D) between the width s1 of the baffle plate 30 shown in FIG. 1 and the inner diameter D of the stirring vessel 10 is not particularly limited, but is a general design value of 0.05 or more and 0.20. The following is preferable. Further, a gap may be formed between the baffle plate 30 and the inner peripheral surface of the stirring tank 10, and the width s <b> 2 of the gap between the baffle plate 30 and the inner peripheral surface of the stirring tank 10 and the width of the baffle plate 30. The ratio (s2 / s1) to s1 is preferably 0 or more and 0.50 or less.

  Further, the ratio (s3 / D) between the distance s3 from the inner peripheral surface of the stirring tank 10 to the radially inner end of the baffle plate 30 and the inner diameter D of the stirring tank 10 is 0.05 or more, which is a general design value. .25 or less is preferable.

  The number of baffle plates 30 is not particularly limited, but is, for example, 1 or more and 10 or less, and preferably 2 or more and 8 or less.

  In the agitation tank 10, as shown in FIG. 1, a gas supply pipe 42 for supplying gas, a pipe 41 for supplying liquid, and the like are installed. The gas supply pipe 42 is installed in the lower part of the stirring tank 10, and the pipe 41 is installed in the upper part of the stirring tank 10.

  The capacity V of the agitation tank 10 is not particularly limited. However, when the capacity V is small, the time required for the object 50 to be agitated to become uniform from a non-uniform state is short, and thus the effect of the present invention. May appear. Therefore, the volume V of the stirring tank 10 is preferably 30 L, more preferably 50 L or more, and preferably 50000 L or less, more preferably 30000 L or less, and preferably 30 L or more and 50000 L or less, more preferably 50 L or more and 30000 L. It is as follows.

Next, the stirring method using the stirring apparatus 1 mentioned above is demonstrated.
First, the to-be-stirred object 50 is accommodated in the stirring tank 10 of the stirring apparatus 1 having the above-described configuration. At this time, the to-be-stirred object 50 is accommodated in the stirring tank 10 so that the upper end 50a of the to-be-stirred object 50 is located at a fixed position. Specifically, it is preferable that the positional relationship between the upper end 50a of the object to be stirred 50 and the stirring blades 20d and 20u positioned in the lower stage or the upper stage in the axial direction Z be constant. The position of the upper end 50a of the object to be stirred 50 may be controlled by a person confirming the position of the upper end 50a by visual observation, or the control unit (non- (Shown) may be provided and controlled by the control unit.

  The ratio (h1 / H) between the distance h1 between the stirring blade 20d located in the lower stage and the tank bottom 10a of the stirring tank and the height H from the tank bottom 10a of the stirring tank to the upper end 50a of the stirred object 50 is The discharge flow generated by the lower stirring blade 20d is directed to the tank bottom 10a and only the discharge flow generated by the upper and middle stirring blades 20u and 20m merges, or the middle and lower stirring blades. From the viewpoint of preventing the inside of the agitation tank 10 from being divided into two parts by mixing only the discharge flows generated by 20m and 20d and reducing the mixing performance, it is preferably 0.20 or more, and 0.21 or more. More preferably, it is more preferably 0.22 or more, even if the respective discharge flows generated by the three-stage stirring blades 20u, 20m, and 20d merge, From the viewpoint of preventing the mixing performance from deteriorating to the lower part of the stirring tank 10, it is preferably 0.30 or less, more preferably 0.28 or less, and 0.26 or less. Is more preferred (see FIG. 1). Specifically, the ratio of the distance h1 between the stirring blade 20d located in the lower stage and the tank bottom 10a of the stirring tank to the height H from the tank bottom 10a of the stirring tank to the upper end 50a of the stirred object 50 ( h1 / H) is preferably 0.20 or more and 0.30 or less, more preferably 0.21 or more and 0.28 or less, and further preferably 0.22 or more and 0.26 or less. The height H from the tank bottom 10a to the upper end 50a of the stirred object 50 means the height from the lower end of the inner surface of the tank bottom 10a to the upper end 50a of the stirred object 50. The height H is measured in a state where the upper end surface of the object to be stirred 50 is flat without rotating the stirring blade.

  Ratio (h4 / H) between the distance h4 between the stirring blade 20u located in the upper stage and the upper end 50a of the stirred object 50 and the height H from the tank bottom 10a of the stirred tank to the upper end 50a of the stirred object 50 Is preferably 0.19 or more from the viewpoint of preventing the upper end surface of the object to be stirred 50 from being greatly disturbed and exposing the stirring blade 20u located in the upper stage from the upper end 50a of the object to be stirred 50. Is more preferably 25 or more, and even if a flow pattern in which the respective discharge flows generated by the three-stage stirring blades 20u, 20m, and 20d join is obtained, the joined flow reaches the upper part of the stirring tank 10. In view of preventing the mixing performance from deteriorating, it is preferably 0.30 or less, and more preferably 0.27 or less (see FIG. 1). Specifically, the ratio of the distance h4 between the stirring blade 20u located in the upper stage and the upper end 50a of the stirring object 50 to the height H from the tank bottom 10a of the stirring tank to the upper end 50a of the stirring object 50 ( h4 / H) is preferably from 0.19 to 0.30, and more preferably from 0.25 to 0.27.

  If the ratio (H / D) between the height H from the tank bottom 10a of the stirring tank to the upper end 50a of the stirred object 50 and the inner diameter D of the stirring tank is too large, it is generated by the three-stage stirring blades 20u, 20m, and 20d. Since the discharge flows independently form a circulation flow, the mixing performance is deteriorated. If the ratio (H / D) of the height H from the tank bottom 10a of the stirring tank to the upper end 50a of the object to be stirred 50 and the inner diameter D of the stirring tank is too small, the peripheral ends of the stirring blades 20u, 20m, 20d The distance from the wall to the wall becomes large, and uniform mixing in the radial direction cannot be maintained. Therefore, the ratio (H / D) of the height H to the upper end 50a of the stirring object 50 and the inner diameter D of the stirring tank is 0.95 or more and 1.15 or less, more preferably 0.99 or more and 1.13 or less. Is desirable.

  And in the stirring apparatus 1 which accommodated the to-be-stirred object 50, the rotating shaft 11 is rotated and the to-be-stirred object 50 in the stirring tank 10 is stirred.

  According to the stirring device 1 of the present embodiment, the distances between the three stages of the stirring blades 20u, 20m, and 20d are uneven, and the lower stirring blade 20u has a constant distance from the tank bottom 10a of the stirring tank 10. Therefore, when the rotating shaft 11 of the stirring device 1 is rotated to stir the object to be stirred 50 in the stirring tank 10, the three-stage stirring blades 20u, 20m, and 20d as shown in FIG. A flow pattern in which all the generated discharge flows are obtained is obtained. Since the discharge flows generated by the respective stirring blades 20u, 20m, and 20d are all merged, they collide with the inner peripheral surface (or baffle plate) of the stirring tank 10 and are divided in the vertical direction, and the downward flow reaches the tank bottom 10a. The mixing performance in the stirring tank 10 can be improved. Further, since the radial flow type stirring blade 20 having a large shearing force is used, stirring is performed while maintaining the shearing force that the stirring blade 20 gives to the object to be stirred 50 without increasing the power required for stirring. The mixing performance in the tank 10 can be improved.

In general, the flow state of the object to be stirred can be determined by the stirring Reynolds number Re defined by Equation 2. The stirring Reynolds number Re is a dimensionless number that represents the ratio of kinetic energy due to fluid inertia to energy lost due to viscosity. Here, ρ is the liquid density (kg / m ³ ), n is the rotational speed (rpm), d is the outer diameter (m) of the stirring blade, and μ is the liquid viscosity (Pa · s).

  The stirring Reynolds number Re in the present invention is not particularly limited, but when the stirring Reynolds number Re is extremely small, the flow state of the object to be stirred is very weak and the discharge flows are difficult to join. Therefore, the stirring Reynolds number Re is preferably 4000 or more.

  By stirring the to-be-stirred object 50 in the stirring tank 10 using the stirring apparatus 1, it can be used for various chemical processes. For example, the stirring object 1 in the stirring tank 10 can be stirred using the stirring device 1 to perform gas-liquid reaction, emulsification, or solid-liquid dispersion.

  Moreover, the to-be-stirred thing 50 in the stirring tank 10 can be stirred using the stirring apparatus 1, and an emulsion and suspension can also be manufactured. Examples of the emulsion that can be produced according to the present embodiment include an oil-in-water emulsion composition, an emulsified cosmetic and quasi-drug, an emulsion composition for food and drink, an emulsified oily food, and the like. Examples of the suspension that can be produced according to this embodiment include a cosmetic slurry composition, a food slurry composition, and an ink pigment mixture.

Moreover, the to-be-stirred object 50 containing an enzyme and a substrate is accommodated in the stirring tank 10 of the stirring apparatus 1, and this to-be-stirred object 50 can be stirred and an enzyme reaction can be performed. Thereby, an enzyme reaction product can be manufactured. Examples of the enzyme reaction product that can be produced according to this embodiment include polyphenols and fatty acids. Many enzyme reactions require a gas such as oxygen, and many by-products increase as the enzyme reaction proceeds and the pH in the reaction solution changes. In such a case, the object to be stirred 50 can be stirred while supplying a gas from the gas supply pipe 42 installed in the stirring tank 10 or supplying a pH adjusting agent from the pipe 41. Examples of the gas supplied from the gas supply pipe 42 include air, oxygen, nitrogen, carbon dioxide, and the like. Examples of the pH adjuster supplied from the pipe 41 include alkali metals such as sodium hydroxide or the like. Examples include alkaline solutions of alkaline earth metal hydroxides and acidic solutions of hydrochloric acid, acetic acid, citric acid, phosphoric acid, and the like.
Examples of the enzymatic reaction performed while stirring with the stirring method or the stirring device of the present invention include, for example, hydrolysis of tea extract using an enzyme having tannase activity (see Japanese Patent No. 4244230), hydrolysis of fatty acids with lipase. Decomposition and the like.

  As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment. For example, in the present embodiment, the three stages of stirring blades 20u, 20m, and 20d are all the same, but if they are radial flow type stirring blades, one stage of stirring blades 20 is the other two stages of stirring blades 20 The three-stage stirring blades 20u, 20m, and 20d may be different from each other. Moreover, in this embodiment, although the some blade | wing 22 which the stirring blade 20 has is the same, the thing from which a magnitude | size and the attached angle differ in the some blade | wing 22 may be contained.

  In the stirring device 1 according to the present embodiment, the baffle plate 30 extends above the upper end 50a of the stirring object 50, but the upper end of the baffle plate 30 is positioned below the upper end 50a of the stirring object 50. (See FIG. 6A). Moreover, in this embodiment, although the lower end of the baffle plate 30 is located above the tank bottom 10a, the lower end of the baffle plate 30 may extend to the tank bottom 10a along the shape of the tank bottom 10a. Good (see FIG. 6B). The baffle plate 30 may be divided in the height direction (see FIG. 6C).

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to such examples.

[Example 1]
Three stages of disk turbine blades having the following dimensions were attached to a stirring tank having a 10% dish-shaped tank bottom shape and an inner diameter of 2100 mm.
Ratio of outer diameter d of stirring blade to inner diameter D of stirring tank (d / D): 0.333
Ratio (b / d) of the height b of the stirring blade to the outer diameter d of the stirring blade: 0.200
Ratio (c / d) of length c in the radial direction of the stirring surface of the blade to the outer diameter d of the stirring blade: 0.25
Ratio of the length c in the radial direction of the stirring surface of the blade to the height b of the stirring blade: 1.25
The ratio (A1 / A2) of the largest projected area A1 to the smallest projected area A2 among the projected areas on the stirring surface of the blades on the plane parallel to the axial direction of the stirring tank (A1 / A2): 1.00
Angle θ between the stirring surface of the blade and a virtual line parallel to the axial direction of the rotation axis: 0 °

A baffle plate having the following shape and dimensions was attached to the stirring tank.
Baffle plate shape: Plate baffle plate Number of baffle plates: 4 Ratio of baffle plate width s1 to stirring blade outer diameter d (s1 / d): 0.07
Ratio (s2 / s1) between the width s2 of the gap between the baffle plate and the inner peripheral surface of the stirring tank and the width s1 of the baffle plate (s2 / s1): 0

  Table 1 shows the amount of the object to be stirred, the position of each stirring blade, and the Reynolds number in the stirring device having the stirring tank and the stirring blade described above. A simulation was performed when the object to be stirred was stirred using such a stirring device, and the flow pattern was determined, the mixing performance of the object to be stirred was evaluated, and the torque average value was measured as follows.

<Flow pattern discrimination method by simulation>
Simulation was performed using general-purpose thermal fluid analysis software. In the simulation, the flow field was calculated assuming a three-dimensional incompressible fluid. From the velocity vector diagram (not shown) of the calculation result, the flow pattern was determined by looking at the direction of flow from each stirring blade. The “three-stage merged flow pattern (three stages)” means that the discharge flow generated by the lower stirring blade 20d faces upward, the discharge flow of the upper stirring blade 20u faces downward, and the three-stage stirring blade This is a flow pattern in which all of the discharge flows are merged. An example of a three-stage merging flow pattern is shown in FIGS. 7 (a) and 7 (d). The “upper two-stage merged flow pattern (upper two stages)” means that the discharge flow generated by the stirring blades 20d located in the lower stage faces downward toward the tank bottom 10a and is generated by the stirring blades 20m and 20u located in the middle and upper stages. The discharge flow is a flow pattern that merges. An example of the upper two-stage merged flow pattern is shown in FIG. The “lower two-stage merged flow pattern (lower two stages)” is a flow pattern in which the stirring blade 20d located in the lower stage and the stirring blade 20m located in the middle stage merge, and the discharge flow generated by the stirring blade 20u located in the upper stage is isolated. That is. An example of the lower two-stage merging flow pattern is shown in FIG.

<Evaluation method of mixing performance of agitated materials by simulation>
After the calculation until the flow field became steady, the upper 10% of the stirring object was set as a tracer (scalar amount), and a 20-second tracer mixing simulation was performed. The mixing time is used as a standard for evaluating the mixing performance of the stirring device and the stirring method. Mixing time refers to the time required to achieve the specified homogeneity within the agitated material after the tracer is charged. The separation strength S was used for quantifying the mixing time in the simulation. The separation strength S is an index representing the non-uniformity of the tracer and is expressed by the following formula 3.
The separation strength S is 1 in the completely separated initial state and 0 in the completely uniformly mixed state. In the calculation, the tracer concentration in each calculation cell was output every 0.2 seconds to obtain the separation strength S, and the time from when the tracer was charged until S = 0.001 was taken as the mixing time. After 20 seconds, extrapolation was performed using an exponential approximation formula.

<Method for measuring torque average value by simulation>
From the simulation results, the change over time in the torque of the stirring shaft was output every 0.2 seconds for 20 seconds, and the average value was used as the torque average value.

[Example 2]
Ratio (h1 / H) of the distance h1 between the stirring blade located in the lower stage and the tank bottom of the stirring tank to the height H from the tank bottom of the stirring tank to the upper end of the object to be stirred, and the stirring blade located in the lower stage A simulation was performed in the same manner as in Example 1 except that the ratio (h1 / D) between the distance h1 between the tank and the tank bottom of the stirring tank and the inner diameter of the stirring tank was changed as shown in Table 1, and the flow pattern And the mixing performance of the material to be stirred was evaluated.

[Comparative Example 1]
Table 1 shows the ratio (h2 / h3) of the distance h2 between the stirring blade located in the lower stage and the stirring blade located in the middle stage and the distance h3 between the stirring blade located in the upper stage and the stirring blade located in the middle stage. Except for the change, the simulation was performed in the same manner as in Example 1 to determine the flow pattern, evaluate the mixing performance of the stirring object, and measure the torque average value.
[Comparative Example 2]
Table 1 shows the ratio (h2 / h3) of the distance h2 between the stirring blade located in the lower stage and the stirring blade located in the middle stage and the distance h3 between the stirring blade located in the upper stage and the stirring blade located in the middle stage. Except for the change, the simulation was performed in the same manner as in Example 1 to determine the flow pattern and evaluate the mixing performance of the stirring object.
[Comparative Example 3]
The ratio (h2 / h3) of the distance h2 between the stirring blade located in the lower stage and the stirring blade located in the middle stage and the distance h3 between the stirring blade located in the upper stage and the stirring blade located in the middle stage is shown. A simulation was performed in the same manner as in Example 1 except that the change was made as shown in FIG. 1, and the flow pattern was determined and the mixing performance of the stirring object was evaluated.

Table 1 shows the results of discriminating the flow patterns of Examples 1 and 2 and Comparative Examples 1 to 3 and the measurement result of the mixing time of the object to be stirred. Is shown in FIG. The torque 5-section moving average means an average value of 5 sections of torque output every 0.2 seconds, that is, an average value for 1 second. As shown in Table 1, in Comparative Examples 1 and 2, the upper two-stage merged flow pattern (see FIG. 7B and FIG. 8B) in which the discharge flows generated by the upper and middle agitating blades merged is compared. In Example 3, the lower two-stage merged flow pattern (see FIG. 7 (c)) in which the discharge flows generated by the middle and lower agitating blades merged, whereas in Examples 1 and 2, the three-stage merged flow pattern A three-stage merged flow pattern (see FIGS. 7A and 8A) in which the discharge flows generated by the respective stirring blades merged was obtained.
Therefore, it was found that the stirring methods of Examples 1 and 2 had better uniform mixing properties than the stirring methods of Comparative Examples 1 to 3. Moreover, the mixing time of Examples 1 and 2 is shorter than that of Comparative Examples 1 to 3 (see Table 1 and FIG. 9). Furthermore, as shown in FIG. 10, it can be seen that the stirring method of Example 1 has a lower torque average value than the stirring method of Comparative Example 1. Therefore, it was found that the stirring method of Example 1 can improve the mixing performance without requiring large power as compared with Comparative Example 1.

[Comparative Example 4]
Ratio (h1 / H) of the distance h1 between the stirring blade located in the lower stage and the tank bottom of the stirring tank to the height H from the tank bottom of the stirring tank to the upper end of the object to be stirred, and the stirring blade located in the lower stage The simulation was performed in the same manner as in Example 1 except that the ratio (h1 / D) between the distance h1 between the tank and the tank bottom of the stirring tank and the inner diameter of the stirring tank was changed as shown in Table 2, and the flow pattern And the mixing performance of the material to be stirred was evaluated.
[Comparative Example 5]
Ratio (h1 / H) of the distance h1 between the stirring blade located in the lower stage and the tank bottom of the stirring tank and the height H from the tank bottom of the stirring tank to the upper end of the object to be stirred, and the stirring blade located in the lower stage The simulation was performed in the same manner as in Example 1 except that the ratio (h1 / D) between the distance h1 between the tank and the tank bottom of the stirring tank and the inner diameter of the stirring tank was changed as shown in Table 2, and the flow pattern And the mixing performance of the material to be stirred was evaluated.

  The flow pattern discrimination results of Examples 1 and 2 and Comparative Examples 4 and 5 and the measurement results of the mixing time of the materials to be stirred are shown in Table 2. As shown in Table 2, in Comparative Example 4, the lower two-stage merged flow pattern (see FIG. 7C) was obtained. Moreover, although the comparative example 5 is a 3 step | paragraph merge flow pattern (refer FIG.7 (d)), the circulating flow which joined is not reaching to the tank bottom, compared with Example 1 and 2, it is uniform in a tank. Mixability is low. In addition, as shown in Table 2, the stirring methods of Examples 1 and 2 have a shorter mixing time than the stirring methods of Comparative Examples 4 and 5.

Example 3
The ratio of the amount L of the substance to be stirred to be accommodated in the stirring tank, the height H at the upper end of the object to be stirred, the height H from the tank bottom of the stirring tank to the upper end of the object to be stirred and the inner diameter D of the stirring tank ( H / D) and the ratio (h1 / D) of the distance h1 between the stirring blade located in the lower stage and the tank bottom of the stirring tank and the inner diameter D of the stirring tank (h1 / D) was changed as shown in Table 3. A simulation was performed in the same manner as in Example 1 to determine the flow pattern and evaluate the mixing performance of the stirring object.

[Comparative Example 6]
The ratio (h2 / h3) of the distance h2 between the stirring blade located in the lower stage and the stirring blade located in the middle stage and the distance h3 between the stirring blade located in the upper stage and the stirring blade located in the middle stage is shown. Except for the changes shown in FIG. 3, a simulation was performed in the same manner as in Example 3 to determine the flow pattern and evaluate the mixing performance of the object to be stirred.

  Table 3 shows the flow pattern discrimination results of Example 3 and Comparative Example 6 and the measurement results of the mixing time of the object to be stirred. As shown in Table 3, in Comparative Example 6, the upper two-stage merged flow pattern (see FIG. 7B) is obtained, whereas in Example 3, the discharge flow generated by each of the three-stage stirring blades is This is a three-stage merge flow pattern (see FIG. 7A) that merges. Therefore, it was found that the stirring method of Example 3 had better uniform mixing properties than the stirring method of Comparative Example 6. In addition, as shown in Table 3, the stirring method of Example 3 has a shorter mixing time than the stirring method of Comparative Example 6.

[Examples 4 to 6]
A stirring tank having an inner diameter of 2300 mm was used, and the amount of objects to be stirred, the position of each stirring blade, and the Reynolds number were set as shown in Table 4. Except for these, a simulation was performed in the same manner as in Example 1 to determine the flow pattern and evaluate the mixing performance of the stirring object.

[Comparative Examples 7 to 9]
The ratio (h2 / h3) of the distance h3 between the stirring blade located in the upper stage and the stirring blade located in the middle stage, the distance h1 between the stirring blade located in the lower stage and the tank bottom of the stirring tank, and the stirring tank The ratio (h1 / H) of the height H from the tank bottom to the upper end of the object to be stirred and the ratio of the distance h1 between the stirring blade located in the lower stage and the tank bottom of the stirring tank and the inner diameter D of the stirring tank ( Except for changing h1 / D) as shown in Table 4, simulations were performed in the same manner as in Examples 4 to 6 to determine the flow pattern and evaluate the mixing performance of the stirring object.

  Table 4 shows the flow pattern discrimination results of Examples 4 to 6 and Comparative Examples 7 to 9 and the measurement results of the mixing time of the materials to be stirred. As shown in Table 4, in Comparative Examples 7 to 9, the upper two-stage merged flow pattern (see FIG. 7B) is obtained, whereas in Examples 4 to 6, it is generated by each of the three stages of stirring blades. A three-stage merged flow pattern (see FIG. 7A) in which the discharged flows merge. Therefore, it was found that the stirring methods of Examples 4 to 6 had better uniform mixing properties than the stirring methods of Comparative Examples 7 to 9. Further, as shown in Table 4, the stirring methods of Examples 4 to 6 have a shorter mixing time than the stirring methods of Comparative Examples 7 to 9.

Example 7
A stirring tank having an inner diameter of 288 mm was used, and the amount of objects to be stirred, the position of each stirring blade, and the Reynolds number were set as shown in Table 5. Except for these, a simulation was performed in the same manner as in Example 1 to determine the flow pattern and evaluate the mixing performance of the stirring object. In addition, an actual experiment was performed using an agitator having the same shape as that of the agitator used in the simulation, and the flow pattern was discriminated and the mixing performance was evaluated.

<Flow pattern discrimination method by actual experiment>
Visualization experiments were performed using the resin bead method to determine the flow pattern. The resin bead method is a method in which colored resin beads are brought together with a colorless object to be stirred, the movement is observed with a high-speed camera, and the flow pattern is visually determined by looking at the flow direction from each stirring blade. It is. Similar to the method of discriminating the flow pattern from the simulation results, the flow pattern was discriminated as “three-stage merge flow pattern”, “upper two-stage merge flow pattern”, and “lower two-stage merge flow pattern”.

<Evaluation method of mixing performance of to-be-stirred object by actual experiment>
In order to measure the mixing time, which is a reference for evaluating the mixing performance of the stirring device and the stirring method, an alkali response experiment was conducted. In the alkali response experiment, an alkaline liquid is dropped as a tracer in the stirring tank, and a change in pH with time is detected by a pH sensor installed in the lower part of the tank to determine the mixing time. In the experiment, the NaOH solution was added while the pH of the solution in the tank was adjusted to 4.5 ± 0.1 and stirred, and the numerical value output from the pH meter was obtained over time. Sampling was performed at a cycle of 0.2 seconds until 300 seconds after the NaOH solution was added. The pH data of each time history was obtained by moving average (5 points) after normalization with numerical values after 0 seconds and 300 seconds. The mixing time was defined as the time until the moving average value of the pH data after normalization first exceeded 0.97.

[Comparative Example 10]
The ratio (h2 / h3) of the distance h3 between the stirring blade located in the upper stage and the stirring blade located in the middle stage, the distance h1 between the stirring blade located in the lower stage and the tank bottom of the stirring tank, and the stirring tank The ratio (h1 / H) of the height H from the tank bottom to the upper end of the object to be stirred and the ratio of the distance h1 between the stirring blade located in the lower stage and the tank bottom of the stirring tank and the inner diameter D of the stirring tank ( Except for changing h1 / D) as shown in Table 5, simulations and real experiments were performed in the same manner as in Example 7 to evaluate the mixing performance of the flow pattern and the stirring object.

  Table 5 shows the flow pattern discrimination results of Example 7 and Comparative Example 10 and the measurement results of the mixing time of the object to be stirred. As shown in Table 5, in both the simulation and the actual experiment, the upper two-stage merged flow pattern (see FIG. 7B) is obtained in Comparative Example 10, whereas in Example 7, the three-stage A three-stage merged flow pattern (see FIG. 7A) in which the discharge flows generated by the respective stirring blades merge. Therefore, it was found that the stirring method of Example 7 had better uniform mixing properties than the stirring method of Comparative Example 10. In addition, as shown in Table 5, the stirring method of Example 10 has a shorter mixing time than the stirring method of Comparative Example 10 in both the simulation and the actual experiment.

[Comparative Example 11]
In Example 1, except that the dimensions of the stirring blades attached to the stirring tank were changed as shown in Table 6, simulation was performed in the same manner as in Example 1 to determine the flow pattern, measure the mixing time of the stirring material, and torque The average value was measured.

  The flow pattern discrimination results of Example 1 and Comparative Example 11, the measurement result of the mixing time of the agitated object, and the measurement result of torque average value are shown in Table 6, and the torque 5-section moving average of Example 1 and Comparative Example 11 is shown. As shown in FIG. As shown in Table 6 and FIG. 11, the torque average value of Comparative Example 11 is larger than that of Example 1. Therefore, it was found that the stirring method of Example 1 can improve the mixing performance without requiring large power as compared with Comparative Example 11.

DESCRIPTION OF SYMBOLS 1 Stirrer 10 Stirrer tank 10a Stirrer tank bottom 11 Rotating shaft 20u Stirrer blade 20m located in upper stage 20m Stirrer blade located in middle stage 20d Stirrer blade located in lower stage 21 Disc 22 Blade 23 Stirring surface 30 Baffle plate 41 Pipe 42 Gas supply pipe 50 Stirred object 50a Upper end of the stirred object h1 Distance between the lower stirring blade and the bottom of the stirring tank h2 Distance between the lower stirring blade and the middle stirring blade h3 Distance between the stirring blade located in the upper stage and the stirring blade located in the middle stage H Height from the bottom of the stirring tank to the upper end of the object to be stirred D Inner diameter of the stirring tank

Claims (9)

Using a stirrer provided with a cylindrical stirring tank, a rotating shaft arranged along the central axis of the stirring tank, and a plurality of stirring blades attached to the rotating shaft, the container is accommodated in the stirring tank. A stirring method for stirring a liquid object to be stirred,
The stirring blades are all radial flow type stirring blades, and are attached in three stages at intervals in the axial direction of the rotating shaft,
A ratio (h2) between a distance h2 between the stirring blade located in the lower stage and the stirring blade located in the middle stage and a distance h3 between the stirring blade located in the upper stage and the stirring blade located in the middle stage / H3) is 0.50 or more and 0.95 or less, and the distance h1 between the stirring blade located in the lower stage and the tank bottom of the stirring tank, and the upper end of the object to be stirred from the tank bottom of the stirring tank Up to a height H ratio (h1 / H) of 0.20 to 0.30,
A stirring method of rotating the rotating shaft to stir the object to be stirred. The stirring device has a baffle plate attached to the inner peripheral surface of the stirring tank,
The ratio (h1 / D) between the distance h1 between the stirring blade located in the lower stage and the tank bottom of the stirring tank and the inner diameter D of the stirring tank is 0.190 or more and 0.345 or less. Item 2. The stirring method according to Item 1.   The stirring method of Claim 1 or 2 which stirs the to-be-stirred thing in the said stirring tank using the said stirring apparatus, and performs gas-liquid reaction, emulsification, or solid-liquid dispersion.   The stirring method according to any one of claims 1 to 3, wherein an enzyme reaction is performed by stirring an object to be stirred in the stirring tank using the stirring device. The stirring device has a gas supply pipe installed at the lower part of the stirring tank, and a pipe installed at the upper part of the stirring tank,
5. The enzyme reaction is performed by stirring the object to be stirred in the stirring tank while performing one or both of gas supply from the gas supply pipe and liquid supply from the pipe. The stirring method described in 1.   The manufacturing method of the emulsion using the stirring method of Claim 3.   A method for producing a suspension using the stirring method according to claim 3.   The manufacturing method of the enzyme reaction product using the stirring method of Claim 4 or 5. A stirring apparatus comprising a cylindrical stirring tank, a rotating shaft arranged along the central axis of the stirring tank, and a plurality of stirring blades attached to the rotating shaft,
A baffle plate is attached to the inner peripheral surface of the stirring tank,
The stirring blades are all radial flow type stirring blades, and are attached in three stages at intervals in the axial direction of the rotating shaft,
A ratio (h2) between a distance h2 between the stirring blade located in the lower stage and the stirring blade located in the middle stage and a distance h3 between the stirring blade located in the upper stage and the stirring blade located in the middle stage / H3) is 0.50 or more and 0.95 or less, and the ratio (h1 /) between the distance h1 between the stirring blade located in the lower stage and the tank bottom of the stirring tank and the inner diameter D of the stirring tank A stirring apparatus in which D) is 0.190 or more and 0.345 or less.