WO2016194590A1

WO2016194590A1 - Stirring device

Info

Publication number: WO2016194590A1
Application number: PCT/JP2016/064429
Authority: WO
Inventors: 義晴関島; 昌男久保; 大輔鴫原
Original assignee: 株式会社ヤクルト本社
Priority date: 2015-05-29
Filing date: 2016-05-16
Publication date: 2016-12-08
Also published as: JP6754358B2; JPWO2016194590A1

Abstract

The purpose of the present invention is to provide a stirring device that has high stirring performance, suppresses formation of bubbles in a liquid during stirring, can manufacture a mixed product and the like with little dissolved oxygen, and can exhibit required stirring performance regardless of the volume of liquid within a stirring tank. To this end, a stirring device according to the present invention is configured such that: a rotating shaft (20) for a stirring paddle (2) extends on a center axis (Lo) for a stirring tank (1); the stirring paddle (2) as a whole is plate shaped and has opening parts (22) extending in the vertical direction, and the outer edge part of the stirring paddle (2) in the radial direction extends in the vertical direction; the diameter dimension (width dimension D2) for the stirring paddle (2) is 60% or less of the internal diameter (D1) of the stirring tank; the bottom surface (12) of the stirring tank (1) is a conical shape; and the stirring device has a rotating mechanism (3) that non-uniformly rotates the rotating shaft (20) for the stirring paddle (2).

Description

Stirrer

The present invention relates to an agitation apparatus that includes an agitation tank and an agitation blade and mixes and agitates a liquid filled in the agitation tank.

In various fields such as beverage production and polymer chemistry, stirring devices having stirring blades are widely used.
When a stirring device having a stirring blade is used, the liquid to be stirred is stirred by injecting the liquid to be stirred into the stirring tank and rotating the stirring blade provided in the stirring tank. As the stirring blade, a paddle type stirring blade or a screw type stirring blade is generally used.
For example, a stirrer used in the field of beverage production has one or more paddle-type or screw-type stirrers arranged on a rotating shaft, and the rotating shaft is arranged at a position deviated from the center or center of a cylindrical stirring tank. is doing.

Here, when the liquid is stirred by rotating the stirring blade, bubbles may be generated on the surface of the liquid (so-called “foaming”). And if the amount of such foam generated is large (if foaming is severe), the generated foam will not disappear even if the stirring is completed, and the air contained in the foam acts as a heat insulating agent. Even if the sterilized liquid is heated and sterilized, heat is not sufficiently transmitted and sterilization may be insufficient. In addition, when filling the stirred liquid, the remaining foam may enter the filled product and cause a shortage of capacity.
Therefore, in the stirring device, it is required to suppress the generation of bubbles during stirring.

In a conventional stirring apparatus having a paddle type stirring blade, when the liquid level of the liquid to be stirred is substantially equal to the vertical position of the stirring blade, for example (when the paddle type stirring blade is hanging on the liquid level) It has been confirmed that foaming becomes intense. Therefore, in the paddle type stirring blade, in order to suppress foaming, the stirring blade is completely immersed in the liquid to be stirred in order to prevent the stirring blade from being applied to the liquid surface of the liquid to be stirred. There are cases where more liquid must be stirred than is necessary. In addition, the conventional stirring device having a screw type stirring blade has the same problem.
However, since the liquid exceeding the required amount is discarded after stirring, there is a problem that the amount of liquid loss increases. In order to solve such a problem, it has been required to suppress foaming regardless of the amount of liquid injected into the agitation tank and to maintain a necessary agitation force.
However, no stirrer has yet been proposed that can maintain the necessary stirring force while suppressing the generation of bubbles during stirring regardless of the amount of liquid filled in the stirring tank.

As another conventional technique, there is a conventional technique having a plate-like (so-called “comb-shaped”) stirring blade having an opening (Patent Document 1). Depending on the shape and the like, the required stirring performance may not be exhibited, or a large amount of bubbles may be generated and the dissolved oxygen content of the preparation may exceed the allowable limit. Therefore, regardless of the amount of liquid filled in the agitation tank, the necessary agitation force cannot be maintained while suppressing the generation of bubbles during agitation.

JP-A-8-215554

The present invention has been proposed in view of the above-described problems of the prior art, and manufactures preparations and the like with a small amount of dissolved oxygen by suppressing foaming of liquid during stirring regardless of the volume of liquid in the stirring tank. An object of the present invention is to provide a stirring device that can perform the required stirring performance for different volumes of liquid.

The stirring device (100) of the present invention is a stirring device having a stirring tank (1) and a stirring blade (2).
The rotating shaft (20) of the stirring blade (2) extends to the central axis (Lo) of the stirring tank (1),
The stirring blade (2) has a flat plate shape as a whole, and has an opening (22) extending in the longitudinal direction. The radially outer edge of the stirring blade (2) extends in the vertical direction. And
The diameter direction dimension (width dimension D2) of the stirring blade (2) is 60% or less of the stirring tank inner diameter (D1),
The bottom surface (12) of the stirring tank (1) has a conical shape,
It has the rotation mechanism (3) which rotates the rotating shaft (20) of a stirring blade (2) at non-uniform speed.

In the present invention, the bottom surface (12) of the stirring vessel (1) has a conical shape, and the central axis (Lc) of the conical shape is inclined with respect to the central axis (Lo) of the stirring vessel (1) (so-called “ The “conical” shape is preferred.

In the present invention, the diameter direction dimension (width dimension D2) of the stirring blade (2) is preferably 40 to 60% of the inner diameter (D1) of the stirring tank.
The vertical dimension (H2) of the stirring blade (2) is preferably 100 to 300% of the dimension in the diameter direction (width dimension D2).
Furthermore, the stirring device of the present invention preferably has only one stirring blade (2).

In the present invention, the area of the opening (22) with respect to the stirring blade (2) (the total area of the stirring blade 2: here, the area of the stirring blade 2 when it is assumed that the opening 22 is not opened). Is preferably 20 to 50%.
Further, the region other than the opening (22) in the stirring blade (2) and continuously extending in the vertical direction (the portion corresponding to the “comb teeth” in the comb stirring blade: so-called “comb”) "(24)) are preferably provided in 4 to 6 pieces.

In this invention, it is preferable that the lower end part of the stirring blade (2) is extended in parallel with the area | region where the inclination angle with respect to the horizontal surface in the bottom face (12) of a stirring tank (1) is the largest.

In carrying out the present invention, the rotating mechanism (3) for rotating the rotating shaft (20) of the stirring blade (2) at a non-uniform speed may be a mechanical rotating mechanism, even if it has a rotation control mechanism by electronic control. There may be. If it is a mechanical rotation mechanism, for example, a mechanism using an elliptical gear or a non-circular gear (for example, an egg-shaped gear) can be employed.

According to the present invention having the above-described configuration, the rotating shaft (20) of the stirring blade (2) extends to the central axis (Lo) of the stirring tank (1). Foaming can be suppressed as compared with the case where the center axis (Lo) of the tank (1) is deviated.
And although the stirring blade (2) of this invention is flat as a whole, since it has the opening part (22) extended in the vertical direction, in order to stir, the stirring blade (2) is submerged. The resistance at the time of rotation does not increase too much, and the liquid in the stirring vessel (1) is also prevented from co-rotating with the stirring blade (2), thereby preventing a reduction in stirring performance.
According to the present invention, since the radially outer edge of the stirring blade (2) extends in the vertical direction, it is compared with the case where the stirring blade (2) is inclined with respect to the rotation shaft (20). And foaming can be suppressed.
Further, the diameter direction dimension (width dimension D2) of the stirring blade (2) is 60% or less of the stirring tank inner diameter (D1), and the generation of foam (foaming) is suppressed without deteriorating the stirring performance. Therefore, the dissolved oxygen amount in the liquid after stirring is suppressed.

The bottom surface (12) of the stirring tank (1) of the present invention has a conical shape and can suppress the generation of bubbles during stirring.
Furthermore, by rotating the rotating shaft (20) of the stirring blade (2) at a non-uniform speed by the rotating mechanism, co-rotation and the like are suppressed, and sufficient stirring performance can be obtained.
As a result, according to the present invention, without using a baffle or a baffle plate, it is possible to produce a preparation having a high stirring performance, suppressing foaming of liquid during stirring, and having a small amount of dissolved oxygen. In addition, the required stirring performance can be exhibited for different volumes of liquid.

In the present invention, the bottom surface (12) of the stirring vessel (1) has a conical shape, and the central axis (Lc) of the conical shape is inclined with respect to the central axis (Lo) of the stirring vessel (1) (so-called “ (Inclined conical shape), which eliminates the need to place the inlet / outlet directly under the agitation tank while maintaining the effect of suppressing foaming during agitation. I can do it.
Alternatively, in the present invention, if the diameter direction dimension (D2) of the stirring blade (2) is 40 to 60% of the inner diameter (D1) of the stirring tank, the stirring blade (2) is too small and the stirring performance is deteriorated. Is prevented, viscosity resistance due to the liquid existing between the side wall (11) of the stirring tank (1) and the radially outer end of the stirring blade (2) is suppressed, and sufficient stirring performance is obtained. I can do it.

In the present invention, if the vertical dimension (H2) of the stirring blade (2) is 100 to 300% of the dimension in the diameter direction, the vertical dimension of the comb stirring blade (2) becomes too short, and the stirring tank It is possible to prevent a situation in which the liquid existing in the upper region of (1) is not stirred by the comb-type stirring blade (2). At the same time, since the vertical dimension (H2) of the stirring blade (2) is prevented from becoming too large, the stirring blade (2) is accommodated in the inner space of the stirring tank (1) and the upper mirror (13). I can do it.
Further, since the vertical dimension (H2) of the stirring blade (2) is prevented from becoming too large, the upper portion of the stirring blade (2) exists in a region where no liquid exists, and the upper portion of the stirring blade Can be prevented from being simply immersed in the liquid without being immersed in the liquid.
Furthermore, if the stirring device of the present invention is configured to have only one stirring blade (2), the amount of bubbles generated during stirring is suppressed, and the dissolved oxygen content in the prepared product after stirring exceeds the reference value. Can be prevented.

Here, in the present invention, if the area of the opening (22) is 20 to 50% with respect to the stirring blade (2), that is, the stirring blade when it is assumed that the opening (22) is not opened. If the area of the opening (22) is 20 to 50% of the area of (2), the area of the opening (22) with respect to the stirring blade (2) is too small (less than 20%). Therefore, the resistance at the time of rotating the stirring blade (2) does not increase too much, and the liquid in the stirring tank (1) is suppressed from co-rotating with the stirring blade (2). The stirring performance is prevented from being lowered.
On the other hand, since the area of the opening (22) is not too large (greater than 50%) with respect to the stirring blade (2), the region in which the liquid is stirred in the stirring blade (2) (part other than the opening) ) Is not reduced too much, and the situation where the liquid is not sufficiently stirred and mixed even if the stirring blade (2) is rotated is prevented.

In addition to this, the region other than the opening (22) in the stirring blade (2) and continuously extending in the vertical direction (the portion corresponding to the “comb teeth” in the comb stirring blade: If four to six so-called “combs” 24) are provided, inconvenience due to too few combs (24) (increased resistance to rotate the stirring blade 2 and the liquid in the stirring tank 1). Rotation and stirring performance can be prevented). At the same time, the width dimension of the portion (comb (24)) extending in the vertical direction becomes too small and can be prevented from being bent and deformed due to resistance during stirring.

It is front sectional drawing which shows the stirring apparatus which concerns on embodiment of this invention. It is a front view of the stirring blade in embodiment. FIG. 3 is a side view corresponding to the front view of FIG. 2. It is explanatory drawing explaining the shape of the bottom part of the stirring tank in embodiment. It is a top view explaining the paddle type stirring blade used in the experiment example. FIG. 6 is a front view of the paddle type stirring blade of FIG. 5. It is a top view of the comb type stirring blade used in the example of an experiment. It is a front view of the comb-shaped stirring blade of FIG. It is a top view explaining a comb-shaped stirring blade whose outer peripheral edge is twisted. FIG. 10 is a front view of the comb stirring blade of FIG. 9. It is explanatory drawing explaining the bottom face of a single flow. It is explanatory drawing explaining the cone-shaped bottom face. It is a top view which shows the stirring blade which added the reinforcing material.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
In FIG. 1, an agitation apparatus according to an embodiment of the present invention is indicated generally by the reference numeral 100.
In FIG. 1, the stirring device 100 includes a stirring tank 1, a stirring blade 2, and a rotating blade rotating mechanism 3, and the rotating blade rotating mechanism 3 includes an electric motor 31 and an inconstant speed rotating mechanism 32. The non-uniform speed rotation mechanism 32 is a mechanical rotation mechanism that rotates the rotary shaft 20 of the stirring blade 2 at a non-uniform speed. For example, a mechanism using an elliptical gear or a non-circular gear (for example, an egg-shaped gear) is employed. I can do it.
In addition, as the inconstant speed rotation mechanism, not only a mechanical rotation mechanism but also, for example, a rotation control mechanism by electronic control can be used.

The agitation tank 1 has a cylindrical side wall part 11, a bottom surface (hereinafter referred to as “bottom part”) 12 connected to the lower end of the side wall part 11, and an upper mirror 13 formed at the upper end of the side wall part 11. Yes.
Above the upper mirror 13, the rotary blade rotating mechanism 3 is provided via members indicated by reference numerals 4 and 5. The rotating blade rotating mechanism 3 includes an electric motor 31 and an inconstant speed rotating mechanism 32, and although not explicitly shown, the output shaft of the electric motor 31 is connected to the input shaft of the inconstant speed rotating mechanism 32, so The output shaft of the fast rotating mechanism 32 is connected to the rotating shaft 20 of the stirring blade 2.
The agitation tank 1 is supported by an exterior body plate 6, and a plurality of legs 7 are provided below the exterior body plate 6.
In the stirring device 100 shown in FIG. 1, reference numeral 16 indicates an injection / discharge port for injecting a fluid to be stirred into the stirring tank 1 and discharging the stirred fluid from the stirring tank 1. Reference numeral 15 denotes a flow path for injecting a fluid to be stirred into the stirring tank 1 and discharging the stirred fluid from the stirring tank 1. The injection / discharge flow path 15 communicates with the injection / discharge port 16. Yes.

The rotating shaft 20 of the stirring blade 2 is disposed so as to coincide with the central axis Lo (shown by a one-dot chain line in FIG. 1) of the stirring tank 1. Further, the rotating shaft 20 of the stirring blade 2 is not deviated radially outward with respect to the central axis Lo of the stirring tank 1.
According to the inventor's experiment, when the rotating shaft 20 of the stirring blade 2 is deviated with respect to the central axis Lo of the stirring vessel 1, the rotating shaft 20 of the stirring blade 2 is equal to the central axis Lo of the stirring vessel 1. It has been confirmed that the foaming is more intense than in the case of doing so.
In FIG. 1, reference numeral 12I denotes a cooling water supply port of the bottom portion 12, reference numeral 12E denotes a cooling water discharge port of the bottom portion 12, reference numeral 14I denotes a cooling water supply port on the side surface of the stirring tank 1, and reference numeral 14E denotes a side surface of the stirring tank 1. The cooling water discharge ports are respectively shown, and reference numeral 51 denotes a cooling water circulation pipe. Depending on the type of fluid to be stirred, when the fluid temperature rises during stirring, the quality of the prepared product after stirring may deteriorate. In order to prevent such deterioration, the cooling water is supplied and circulated, and the cooling water supply ports 12I and 14I, the cooling

water discharge ports

12E and 14E, and the cooling water circulation are performed in order to suppress an increase in the temperature of the agitated fluid. A piping 51 is provided. Moreover, it is also possible to inject | pour warm water here instead of cooling water, and to warm a preparation.

The stirring blade 2 will be described based on FIGS. 2 and 3 and also with reference to FIG.
2 and 3, the stirring blade 2 has a symmetrical shape with respect to the center line Lc2 indicated by a one-dot chain line in FIG. Here, the center line Lc2 extends so as to overlap the center axis Lo (see FIG. 1) of the stirring tank 1.
The stirring blade 2 is a so-called “comb-shaped” stirring blade, and is formed such that the outer shell wire of a flat plate member has a pentagonal shape. In FIGS. 2 and 3, the pentagonal flat plate shape is formed. The entire member is denoted by reference numeral 21. A plurality of openings 22 are formed in the stirring blade 2, and each of the openings 22 is formed in a rectangular shape (strip shape). The openings 22 are formed by, for example, press punching or fusing. Processed.
Here, the term “flat plate” indicating the shape of the stirring blade 2 is configured such that a shape in which a reinforcing material is added to the back surface of the stirring blade 2 and a part of the thickness of the stirring blade 2 are different from other portions. It is also intended to encompass the shape. For example, FIG. 13 shows a state in which a reinforcing material 148 is added to the stirring blade 2.

In FIG. 2, the stirring blade 2 is formed with openings 22 (6 in total) in three rows in the left-right direction and in two rows in the up-down direction. Each of the openings 22 has a vertical dimension that is much longer than the horizontal dimension. The stirring blade 2 is formed with a plurality of rectangular notches 23 at the upper and lower ends. With respect to the position in the left-right direction in FIG. As a result, in FIG. 2, on the stirring blade 2, four vertical bars (combs) 24 extending in the vertical direction and three horizontal bars 25 extending in the horizontal direction intersect and are integrally formed. Has been.
As shown in FIG. 2, the outer peripheral edge portion 21 s (the radially outer edge portion of the stirring blade 2) of the stirring blade 2 extends in the vertical direction. In other words, the outer peripheral edge 21 s (the radially outer edge of the stirring blade 2) of the stirring blade 2 is not twisted with respect to the rotating shaft 20. As shown in FIG. 9, the term “twist” refers to the direction in which the width of the comb (vertical beam) 241D extends is twisted at an angle δ with respect to the radial direction Lh. Sure. When the outer peripheral edge is twisted like the stirring blades shown in FIGS. 9 and 10, the amount of foaming increases.
As shown in FIG. 3, the thickness dimension t 21 of the stirring blade 2 is set smaller than the outer diameter d 20 of the rotating shaft 20. Here, when the reinforcing material 148 is added to the stirring blade 2 (for example, FIG. 13), the thickness dimension of the portion may be equal to or larger than the outer diameter d20 of the rotating shaft 20.

As shown in FIG. 1, the width dimension D2 of the stirring blade 2 is smaller than the inner diameter D1 of the stirring tank 1, and is set to 60% or less.
More specifically, the width dimension D2 (diameter direction dimension) of the stirring blade 2 is set to 40 to 60% of the inner diameter D1 of the stirring tank 1.
When the width dimension D2 of the stirring blade 2 is less than 40% of the inner diameter D1 of the stirring tank 1, the stirring performance decreases. On the other hand, when the width dimension D2 of the stirring blade 2 is larger than 60% of the inner diameter D1 of the stirring tank 1, the liquid in the stirring tank 1 becomes difficult to be mixed and stirred, and the amount of foaming increases and the dissolved oxygen concentration Becomes higher.

In FIG. 1, the bottom 12 of the stirring tank 1 has an inclined conical shape. The inclined cone shape is a shape indicated by reference numeral 12 (the bottom of the stirring tank 1) in FIG. 4B, and is a so-called “inclined conical” shape.
In the case of a normal conical shape, as shown in FIG. 4 (1), the central axis of the conical shape that is a rotating figure (the axis indicated by the dotted line extending in the vertical direction in FIG. 4 (1)) is the vertical axis. Match. On the other hand, in the “inclined conical” shape of FIG. 4 (2), the conical center axis Lc (the axis indicated by the dotted line in FIG. 4 (2)) as the rotating body figure is the center axis Lo of the stirring tank 1. In contrast, it is inclined (inclination angle θ). In FIG. 1, θ is 6.5 ° and α is 85 °.
In addition to FIG. 4 (2), also in FIG. 1, the inclined conical shape constituting the bottom surface 12 of the stirring tank 1 does not coincide with the central axis Lo of the stirring tank 1. The inclined conical shape of the bottom surface 12 is a conical shape that is asymmetric with respect to the central axis Lo.

4 (2), the angle between the inclined conical central axis Lc and the central axis Lo of the stirring vessel 1 is defined as 2α, where the angle of the inclined conical surface forming the bottom surface 12 of the stirring vessel 1 is 2α. Assuming the inclination angle θ, the numerical value of α and the inclination angle θ are set on a case-by-case basis according to various stirring conditions, and α is particularly preferably 75 to 88 °.
2, if the angle formed by the lower end of the stirring blade 2 and the center line Lc2 of the stirring blade 2 (which coincides with the central axis Lo of the stirring tank 1) is β, FIG. 1 and FIG. As is clear from the above, β = α−θ. As shown in FIG. 1, the lower end portion of the stirring blade 2 extends in parallel with the inclination of the gradient of the bottom surface 12 of the stirring tank 1 (inclination in the left region of FIG. 1).
2 and 3, reference numeral 26 denotes an impeller boss through which the rotary shaft 20 passes, and is supported by the known means with respect to the rotary shaft 20.

In FIG. 2, the vertical dimension H2 of the stirring blade 2 is preferably set in the range of 100% to 300% with respect to the width dimension D2.
If the ratio is too large (for example, more than 300%), the longitudinal dimension (vertical dimension, vertical dimension) of the stirring blade 2 becomes too large, so that the stirring blade 2 can be accommodated in the stirring tank 1. It may be impossible. Further, when the longitudinal dimension of the stirring blade 2 is increased, the upper region of the stirring blade 2 is not immersed in the liquid to be stirred, and the region is only stirred, so that portion is wasted.
On the other hand, when the vertical dimension H2 of the stirring blade 2 is less than 100% of the width dimension D2, the vertical dimension H2 of the stirring blade 2 becomes too short, and the liquid present in the upper region of the stirring tank 1 is stirred. There is a possibility that the blade 2 may not be stirred.
Further, the position of the stirring blade 2 on the vertical axis is preferably closer to the bottom surface 12 so that stirring can be performed even when the amount of the stirrable object is small.

The stirring device of the present invention is preferably provided with one stirring blade 2.
When a plurality of stirring blades 2 are installed (for example, when two stirring blades having four combs on the central axis are installed at the top and bottom), the amount of bubbles generated increases, and dissolved oxygen in the prepared product after stirring The amount may exceed the reference value. Therefore, the stirring device 100 according to the illustrated embodiment includes only one comb-type stirring blade.

Here, the area of the opening 22 with respect to the entire area of the stirring blade 2 (area surrounded by the outer shell line of the stirring blade 2: area of the stirring blade 2 when the opening 22 is not provided) The proportion is preferably 20% to 50%.
In the comb-type stirring blade, if the area of the opening 22 is less than 20% with respect to the entire area of the stirring blade 2, the opening 22 is too small, and the amount of liquid that passes through the opening 22 is also reduced. The resistance when rotating the comb-type stirring blade 2 in the liquid for stirring becomes too large. And since the liquid in the stirring tank 1 will co-rotate with the comb-type stirring blade 2, stirring performance will fall.
On the other hand, if the area of the opening 22 is larger than 50% with respect to the entire area of the stirring blade 2, the area of the comb-type stirring blade 2 other than the opening 22 (area of the portion where the liquid is stirred) is small. Therefore, even if the comb stirring blade 2 is rotated, the liquid is not sufficiently stirred and mixed.

The number of the vertical bars 24 of the stirring blade 2 is preferably 2 to 6, and more preferably 4 to 6. As apparent from FIG. 2, the opening is divided into two regions in the vertical direction.
In a region other than the opening, two to six portions 24 (portions corresponding to “comb teeth” in the comb-type stirring blade: vertical beam) extending continuously in the vertical direction are formed. Preferably, 4 to 6 places are formed. In FIG. 2, four “vertical bars” 24 extending in the vertical direction are formed.
Here, since the comb stirring blade 2 is formed symmetrically about the rotation axis 20 as a symmetry axis, a portion extending in the vertical direction (portion corresponding to “comb teeth” in the comb stirring blade) 24. The number of is always an even number.

The comb-type stirring blade 2 must always have the opening 22 formed therein. This is because the resistance when rotating in the liquid becomes too large as described above, and the liquid in the stirring tank 1 rotates together with the comb type stirring blade.
As described above, the number of the portions 24 extending in the vertical direction (vertical bars corresponding to “comb teeth” in the comb-type stirring blade) is always an even number, so the portions extending in the vertical direction The fact that 24 is less than two places means that the opening 22 is not formed, and the above-mentioned disadvantages (increase in resistance when the stirring blade 2 rotates, co-rotation of the liquid in the stirring tank 1). It will occur.
On the other hand, if there are more than six portions 24 extending vertically (portions corresponding to “comb teeth” in the comb stirring blade: vertical beam), the width dimension of the vertical beam 24 becomes too small, There is a risk that the rigidity of the stirring blade 2 will be insufficient and it will bend and deform due to the resistance during stirring. The number of openings 22 is preferably 2, 6, or 10.
In the illustrated embodiment, the overall shape (shape of the outer shell) of the stirring blade 2 is a pentagon, but it may be rectangular or trapezoidal.

In FIG. 1, the inconstant speed stirring device 32 is configured such that the rotational speed of the rotary shaft 20 of the stirring blade 2 does not become a constant speed (uniform rotational speed).
A conventionally known mechanism can be applied to the inconstant speed stirring device 32. For example, the inconstant speed stirring device can be configured by a gear train using non-circular and asymmetric gears. Moreover, it is also possible to make the rotational speed of the rotating shaft 20 of the stirring blade 2 nonuniform by electronic control.

Here, in the non-uniform speed agitator 32, the ratio of the rotational speed at the low speed to the rotational speed at the high speed is preferably in the range of 1: 1.5 to 1: 4, 1: 1.5 to 1: 3, Particularly preferred is 1: 1.5 to 1: 2.5.
When the speed ratio of the rotational speeds in the unequal speed agitator 32 is close to 1, the speed is almost constant, and it is not possible to enjoy the merits of the unequal speed. On the other hand, when the speed ratio is too large, it is difficult to manufacture a mechanism that realizes such non-uniform speed rotation.
Here, a structure using a non-circular gear is advantageous because the liquid is well mixed.

As shown in FIG. 1, in the illustrated embodiment, the bottom portion 12 of the stirring vessel 1 is conical, and the lower end of the stirring blade 2 can be disposed close to the bottom portion 12 of the stirring vessel 1. Further, the lower end portion of the stirring blade 2 extends in parallel with the gradient of the steepest gradient at the bottom surface 12 of the stirring tank 1.
Therefore, even when the amount of liquid to be stirred is small and the liquid exists only in the vicinity of the bottom portion 12, such a small amount of liquid is reliably stirred and mixed by the rotation of the comb stirring blade 2. The

Various tests were conducted in Experimental Examples 1 to 4 with the stirring device manufactured based on the above-described embodiment as an “Example”.
[Experimental Example 1]
Experimental Example 1 is an experiment on the influence of the shape of the stirring blade on the generation of bubbles (so-called “foaming”).
As shown in Table 1 below, foaming was observed for two types of paddle type stirring blades (“45 ° paddle”, “90 ° paddle”) and one type of comb type stirring blade (“comb type 1”). .
Table 1

The paddle type stirring blade described as “45 ° paddle” in Table 1 is denoted by reference numeral 2A in FIGS. 5 and 6.
The “45 ° paddle” shown in FIGS. 5 and 6 indicates that the orientation of the paddle 240 extending in the radial direction of the paddle type stirring blade 2A is as shown in FIG. 6 with respect to the vertical axis (rotation axis) Lv. It is inclined 45 °. FIG. 6 shows the vertical axis Lv in the left-right direction.
On the other hand, in the paddle type stirring blade described as “90 ° paddle” in Table 1, the paddle 240 of “45 ° paddle” is arranged horizontally with respect to the vertical axis Lv.
In all of the stirring devices having paddle type stirring blades used in the experiment, the stirring blades are installed at two places near the lower part of the stirring tank and the center.

The comb type stirring blade described as “comb type 1” in Table 1 is denoted by reference numeral 2 C in FIGS. 7 and 8.
7 and 8, the outermost comb (vertical beam) 241 C extends in a direction parallel to the (rotation axis) Lv direction of the comb-type stirring blade 2 C in the radial direction (left-right direction in FIGS. 7 and 8). In addition, the width direction of the comb (vertical bar) 241C extends in the radial direction. Further, the “comb mold 1” has four combs, and the lower end portion of the stirring blade is parallel to the horizontal plane on the bottom surface of the stirring tank. The vertical dimension of the stirring blade is 200% of the dimension in the diameter direction, the area of the opening with respect to the stirring blade is 38%, and the diameter dimension of the “comb die 1” in Experimental Example 1 is 50% of the inner diameter of the stirring tank. .
Hereinafter, all of the stirring devices having comb-type stirring blades used in the experiment have one stirring blade.

The bottom shape of the stirring tank used in Example 1 is “conical” shown in FIG. In FIG. 12, the bottom face B1 of the stirring tank has a normal conical shape. “Conical” in Table 1 indicates that the outlet E1 is formed at the center of the bottom of the conical shape convex downward as shown in FIG. 12, and when the liquid in the stirring tank flows out of the outlet E1, the liquid is It flows from all directions of 360 ° (only arrows A2 and A3 are shown in FIG. 12) toward the outlet E1, and does not flow only in one direction.
The stirring pattern is constant speed stirring, and the respective rotation speeds are as shown in Table 1. The rotation speed was set so that the power required for stirring required to rotate the stirring blade was constant. Moreover, the rotating shaft is attached to the center of the stirring tank (center axis position).

Evaluation criteria in Experimental Example 1 are shown in Table 2 below. In Experimental Example 1, water was used as a stirring object.
Table 2

The evaluation points (evaluation ranks) are divided into five levels (the stirring state gets worse as the rank number increases), and the main points to be evaluated for each rank are defined.

The results of Experimental Example 1 are shown in Table 3 below. The “full amount” and “stirring blade surface level” referred to here indicate the water level in the stirring tank, and the “full amount” is a state in which the stirring blade is completely immersed in the liquid. The “surface water level” means a state where the upper end of the stirring blade and the liquid level are substantially equal (a state where the liquid level is in the vicinity of the upper end of the stirring blade (slightly below the upper end)).
Table 3

From Table 3, in the case of a paddle type stirring blade (45 ° paddle, 90 ° paddle), when the stirring blade is located at substantially the same level as the liquid level (stirring blade surface water level), the foaming rank is 2 or It is 3.5, and foaming may occur if stirring is continued.
On the other hand, the comb-type stirring blade (comb die 1) has a gentle rotating flow wave only when the stirring blade is completely immersed in the liquid or when the upper end of the stirring blade is approximately equal to the liquid surface. Not observed.
Therefore, it was confirmed from Experimental Example 1 that if a comb-type stirring blade is used, stirring can be performed while preventing foaming regardless of the amount of liquid to be stirred.

[Experiment 2]
In Experimental Example 2, the influence of the bottom shape of the stirring tank on foaming was verified.
The conditions of Experimental Example 2 are as shown in Table 4 below. The experimental method and the evaluation method in Experimental Example 2 are the same as in Experimental Example 1 described above.
Table 4

The stirring blade used in this experimental example is the same as the “comb type 1” in Experimental example 1. In Experimental example 2, the diametric dimension is 50% of the inner diameter of the stirring tank.
A bottom surface shape described as “single flow” in Table 4 is shown in FIG. 11. In FIG. 11, one outlet E is formed at one location in the vicinity of the cylindrical side wall S on the bottom surface B of the stirring tank, and when the liquid in the stirring tank flows out from the outlet E, the liquid is shown by an arrow. As shown by A1, it is configured to flow out in only one direction.
The stirring pattern is constant speed stirring, and the rotational speeds (constant power required for stirring) are as shown in Table 4. The experiment was performed under the condition that the rotating shaft of the stirring blade was attached to the center line of the stirring tank in an eccentric state (eccentric shaft position), and foaming was likely to occur.

The results of Experimental Example 2 are shown in Table 5 below.
Table 5

According to the results shown in Table 5, “when the stirring blade is approximately equal to the liquid surface (stirring blade surface water level), the foaming of the single flow bottom (Test Example 4) is rank 3 (Table 2). In the conical bottom (Test Example 5), the foaming is rank 2 (Table 2), so that when using a comb-shaped stirring blade, the “conical bottom” is better than the “single-flow bottom”. It was confirmed that foaming was further improved.

[Experiment 3]
In Experimental Example 3, the case where the stirring blade was rotated at a constant speed was compared with the case where the stirring blade was rotated at a non-uniform speed. The “comb-type stirring blade” used in Comparative Example 1 and Example 1 is the same as the “comb-type 1” used in Experimental Example 1, and the diameter dimension is 50% of the inner diameter of the stirring tank.
The experiment was conducted under the conditions shown in Table 6 below, with the stirring power required being constant. In Experimental Example 1, a rotating mechanism (nonuniform stirring) using a pair of non-circular gears was used. The rotation speed of the stirring blade changes from low speed to high speed in half rotation, and further changes from high speed to low speed in half rotation, and the ratio of the rotation speed at low speed to the rotation speed at high speed is 1: 1.75. This device has a structure in which a pair of egg-shaped gears mesh with each other, and the gear connected to the power (motor) rotates at a constant speed, so that the gear connected to the rotating shaft of the other stirring blade is unequal. Rotate at high speed. Therefore, Table 6 shows the number of rotations of the gear rotating at a constant speed.
In Table 6 and below, “control” refers to a tank using a paddle-type stirring blade that has been conventionally used at the time of preparation during beverage production or culturing. ° It has the same structure as a paddle.
In addition, the bottom face shape and the axial position of the stirring tank are described in Table 6 and are the same as those described in Experimental Examples 1 and 2.
Table 6

In Experimental Example 3, it was performed when the stirring blade was completely immersed in the liquid (full amount) and when the upper end of the stirring blade and the liquid surface were approximately equal (stirring blade surface water level).
In Experimental Example 3, the experimental methods of the four items shown in Table 7 below (confirmation of poor mixing, confirmation of mixing state, measurement of dissolved oxygen, measurement of foaming amount) are employed.
In the “Confirmation of mixing state” column of Table 7, the numerical values “(1.5)”, “(1)”, and “(0.3)” indicate the mixing ratio. That is, the mixing ratio of syrup, yogurt, and calcium lactate solution is 1.5: 1: 0.3 (about 5: 3: 1).
Table 7

Table 8 summarizes the experimental results for the four items in Table 7 (confirmation of poor mixing, confirmation of mixing state, measurement of dissolved oxygen, measurement of foaming amount). The poorly mixed part and the mixed state are indices indicating the stirring performance. The smaller the poorly mixed part, the smaller the particle diameter of the preparation, and the smaller the precipitation amount, the better the stirring performance. Further, since the amount of dissolved oxygen increases due to foaming, the amount of dissolved oxygen is an index indicating the degree of foaming.
Table 8

Of the four items, the results relating to the mixed state are shown in Table 9, and the results obtained when the stirring blade was completely immersed in the liquid by measuring the dissolved oxygen concentration (full amount) are shown in Table 10. Table 11 shows the results in the case where the upper end of the liquid and the liquid level are approximately equal (stirring blade surface level). The “precipitation amount” in Table 9 is a numerical value × 100 (%) obtained by dividing the precipitation amount obtained by the method described in Table 7 by the total amount of the preparation to be centrifuged.
Table 9

Table 10

Table 11

According to the evaluation results shown in Tables 8 and 9, in Comparative Example 1, both the poorly mixed portion and the mixed state were significantly inferior to the control.
On the other hand, in Example 1, the poorly mixed part, the particle diameter of the prepared product, and the amount of precipitation were equivalent to the control. Therefore, it was confirmed that Example 1 has a stirring performance equivalent to that of the control.

In addition, in the measurement of the dissolved oxygen concentration, in the case of “full” (Table 10), the dissolved oxygen concentration of 4.59 mg / L in the control at the time of 30 minutes is 2.18 mg / L in Example 1. In Example 1, the dissolved oxygen concentration decreased by 50% or more compared to the control. Also, in the case of “stirring blade surface level” (Table 11), the dissolved oxygen concentration was 4.08 mg / L in Example 1 compared to the dissolved oxygen concentration of 7.23 mg / L in the control after 30 minutes. Significant improvement was seen. In addition, as shown in Table 8, it was confirmed that the foaming amount in Example 1 was very small as compared with the control in both “full amount” and “stirring blade surface water level”.
Therefore, if the configuration described with reference to FIGS. 1 to 4 is combined with the non-uniform rotation motion, the stirring performance is high and the effect of suppressing the generation of bubbles is controlled (the stirring according to the prior art). It was confirmed that the result exceeded that of the tank.

[Experimental Example 4]
In Experimental Example 4, the stirring efficiency (stirring performance) and the amount of bubbles generated (foaming) were measured in order to examine the size of the comb stirring blade.
Table 12 shows the conditions of the two types of stirring blades used in Experimental Example 4 (Example 2, Comparative Example 2).
Table 12

In Table 12, the term “comb shape (50%)” in the row of “stirring blade shape” means that the diameter direction dimension of the comb stirring blade is 50% of the inner diameter of the stirring tank. The term “type (90%)” means that the diameter dimension of the comb type stirring blade is 90% of the inner diameter of the stirring tank.
The comb-type stirring blade of Example 2 is the same as that of Example 1. Further, the comb type stirring blade (“comb type (90%)”) of Comparative Example 2 has four combs, and the lower end portion of the stirring blade is parallel to the horizontal plane on the bottom surface of the stirring tank.
In Table 12, “Example 2” and “Comparative Example 2” have the same power required for stirring, and the ratio of the rotational speed at the low speed and the rotational speed at the high speed of the inconstant speed stirring is 1: 1.75. Yes, the inconstant speed stirring device is the same as in Example 1. Moreover, the rotation speed of the stirring of Table 12 similarly to Example 1 described the rotation speed of the gear rotating at constant speed among the gears used for the inconstant speed stirring apparatus.
Others are the same as described in Experimental Examples 1 to 3.

In Experimental Example 4, the so-called “iodo-hypo method” (see Table 7) is used for stirring performance, and for confirmation of foaming, water is injected into the stirring tank, and the stirring blade is completely immersed in the liquid. About (full amount), it stirred continuously for 30 minutes and dissolved oxygen was measured.
A comparison result of stirring performance is shown in Table 13 below, and a comparison result regarding foaming is shown in Table 14 below.
Table 13

Table 14

According to Table 13, compared with Comparative Example 2, it was confirmed that mixing was completed in a short time when the required power for stirring was constant. From this, it was found that the diameter direction dimension (width dimension) of the comb-type stirring blade is preferably 50% or less of the inner diameter of the stirring tank from the viewpoint of stirring efficiency.
There was no significant difference between samples with respect to the dissolved oxygen concentration (results in Table 14).

The experimental results shown in Table 14 are for the case where the power required for stirring is the same. In this case, as described above, there was no significant difference in the dissolved oxygen concentration between the samples.
For this reason, the rotational speed of Example 2 and Comparative Example 2 was kept constant (73 rpm), and the dissolved oxygen concentration was measured again. The results are shown in Table 15.
Table 15

As a result of performing re-measurement at a constant rotation speed (73 rpm), it was confirmed that the dissolved oxygen concentration in Comparative Example 2 increased compared to Example 2 although the mixing property of Comparative Example 2 was improved. .
From the above, it has been found from Experimental Example 4 that the diameter direction dimension (width dimension) of the comb-type stirring blade is preferably 50% or less of the inner diameter of the stirring tank from the viewpoint of stirring efficiency and dissolved oxygen concentration (foaming suppression).

It should be noted that the illustrated embodiment is merely an example, and is not a description to limit the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Stirring tank 2 ... Stirring blade 3 ... Rotary blade rotating mechanism 11 ... Side wall part 12 ... Bottom part 13 ... Upper mirror 22 ... Opening part 24 ... Vertical beam

Claims

In a stirring tank and a stirring device having a stirring blade,
The rotating shaft of the stirring blade extends to the central axis of the stirring tank,
The stirring blade is entirely flat and has an opening extending in the vertical direction, and the radially outer edge of the stirring blade extends in the vertical direction.
The diameter direction dimension of the stirring blade is 60% or less of the inner diameter of the stirring tank,
The bottom surface of the stirring tank has a conical shape,
A stirrer having a rotating mechanism for rotating the rotating shaft of the stirring blade at a non-uniform speed.
The stirring device according to claim 1, wherein a bottom surface of the stirring tank has a conical shape, and a central axis of the conical shape is inclined with respect to a central axis of the stirring tank.
The stirring device according to any one of claims 1 and 2, wherein a diameter direction dimension of the stirring blade is 40 to 60% of an inner diameter of the stirring tank.
The stirring device according to any one of claims 1 to 3, wherein a vertical dimension of the stirring blade is 100 to 300% of a dimension in the diameter direction.
The stirring device according to any one of claims 1 to 4, wherein an area of the opening with respect to the stirring blade is 20 to 50%.
The stirring device according to any one of claims 1 to 5, wherein 4 to 6 regions other than the opening in the stirring blade and continuously extending in the vertical direction are provided.
The stirring device according to any one of claims 2 to 6, wherein a lower end portion of the stirring blade extends in parallel with a region having a maximum inclination angle with respect to a horizontal plane at a bottom surface of the stirring tank.