JP2010119965A - Agitator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an agitator that can adjust KLa within a predetermined range and keep it at a proper value even under the condition that the rotation speed of agitation and oxygen feed rate cannot be easily increased. <P>SOLUTION: The agitator A includes a nearly cylindrical storage tank 1 for storing a liquid M, a gas-supplying unit 2 for supplying an oxygen-containing gas into the liquid M, an agitation unit 3 installed in the storage tank 1 for agitating the liquid M, and baffle plates 5 attached to the inside of sidewall of the storage tank 1 for converting the flow direction of the liquid M driven by the agitation unit 3 to the other direction. The dimensions of the baffle plates 5 are determined from the oxygen mass-transfer coefficient of the liquid M. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

 The present invention relates to a stirring device that stirs both a gas and a liquid.

2. Description of the Related Art Conventionally, in manufacturing facilities that handle liquids such as biological / chemical factories, stirring devices for uniformly mixing a plurality of liquids or for injecting gas into the liquid have been used.
Here, Patent Document 1 discloses a stirring device for uniformly mixing a plurality of liquids.
The stirrer has a substantially cylindrical shape and a liquid storage tank, a stirrer connected to a drive unit for stirring the liquid, and a flow in a stirring direction generated by the operation of the stirring unit in a vertical direction and a radial direction. A baffle plate for converting and promoting agitation.

In addition, when the agitator is used for culturing animal / plant cells / microorganisms, chemical reaction requiring oxygen for reaction, etc., it is dissolved in a liquid in order to proceed appropriately. It is necessary to maintain the oxygen concentration (dissolved oxygen concentration) at a predetermined value. In that case, the stirring device is provided with an air supply unit that supplies a gas containing oxygen into the liquid. While the agitation unit is agitating the liquid, the gas supply unit supplies the gas into the liquid, whereby the gas and the liquid are both agitated, and the gas is dissolved into the liquid.
It is known that the dissolved oxygen concentration depends on the oxygen transfer capacity coefficient (KLa) of the liquid. KLa is an index representing the ease with which oxygen can be dissolved into a liquid. If the value of KLa is large, the dissolved oxygen concentration can be kept high. Since the value of KLa can be increased by increasing the number of stirring revolutions by the stirring unit or increasing the amount of oxygen supplied, the stirring speed or oxygen supply amount is set to a predetermined value. By doing so, KLa was able to be maintained at an appropriate value.
JP-A-9-29084 (page 4, FIG. 1)

However, for example, in the culture of animal and plant cells, since the cells have a characteristic that they are very weak against external forces, it has been difficult to maintain KLa and dissolved oxygen concentration at appropriate values by the above-described method.
First, when the number of stirring rotations by the stirring unit is increased, the shear stress due to the flow of liquid increases, and there is a risk that cells are damaged and killed by this stress. In addition, the supplied gas becomes bubbles and rises in the liquid, but when the bubbles burst on the liquid surface, there is a possibility that the cells attached to the bubble liquid film are killed by the impact of the burst.
Therefore, it is difficult to increase the stirring speed or the oxygen supply amount in the culture of the cells, etc., and the stirring speed or the oxygen supply amount is set to a predetermined value, and the KLa and dissolved oxygen concentration are set to appropriate values. There was a problem that the method of maintaining could not be adopted.

 The present invention has been made in view of such circumstances, and KLa can be adjusted within a predetermined range and maintained at an appropriate value even under conditions where the rotation speed of stirring and the amount of oxygen supply cannot be easily increased. It is an object of the present invention to provide a stirring device that can be used.

In order to solve the above problems, the present invention employs the following means.
The stirrer of the present invention has a substantially cylindrical shape and stores a liquid, an air supply unit that supplies a gas containing oxygen into the liquid, a stirring unit that is provided in the storage tank and stirs the liquid, The baffle plate is provided inside the side wall of the storage tank and converts the flow of the liquid from the stirring direction by the stirring unit to another direction, and the specifications of the baffle plate are set based on the oxygen transfer capacity coefficient of the liquid The configuration is adopted.

In the present invention adopting such a configuration, the liquid is stirred by the operation of the stirring unit, and the KLa of the liquid rises. Moreover, in this invention, a liquid is further stirred because a baffle plate converts the flow of the stirring direction of a liquid to another direction. Therefore, KLa further increases. Moreover, in this invention, since the air supply part supplies the gas in which oxygen is contained in a liquid with the action | operation of a stirring part, both gas and a liquid are stirred and gas melt | dissolves in a liquid. Here, since the dissolved oxygen concentration depends on KLa, the dissolved oxygen concentration is maintained at a high value when KLa is increasing.
On the other hand, when the specifications of the baffle plate are changed and the flow conversion by the baffle plate is reduced, stirring is not promoted, and therefore Kla does not increase due to the action of the baffle plate. As described above, in the present invention, the value of KLa changes according to the specifications of the baffle plate.

Moreover, the stirring apparatus of this invention employ | adopts the structure that the ratio of the width of a baffle plate with respect to the width | variety of a storage tank is set based on the set oxygen transfer capacity coefficient.
In the present invention employing such a configuration, the value of KLa changes according to the ratio of the width of the baffle plate to the width of the storage tank.

Moreover, the stirring apparatus of this invention employ | adopts the structure that the ratio of the width of a baffle plate with respect to the width | variety of a storage tank is 0.12 or less.
In the present invention employing such a configuration, when the ratio is 0.12 or less, the value of KLa changes substantially linearly according to the value of the ratio.

The stirring device of the present invention employs a configuration in which a plurality of baffle plates are provided at substantially equal intervals in the circumferential direction of the storage tank.
In the present invention employing such a configuration, stirring of the liquid is promoted and stirring in the storage tank proceeds substantially uniformly.

Moreover, the stirring apparatus of this invention employ | adopts the structure that animal and plant cells or microorganisms are culture | cultivated in a liquid.
In the present invention employing such a configuration, the value of KLa changes according to the specifications of the baffle plate even under conditions where the number of stirring revolutions and the amount of oxygen supply cannot be easily increased.

According to the present invention, the following effects can be obtained.
According to the present invention, KLa can be adjusted within a predetermined range and maintained at an appropriate value even under conditions in which the number of stirring rotations and the amount of oxygen supply cannot be easily increased due to the characteristics of objects existing in the storage tank. There is an effect that can be.

Embodiments of the present invention will be described below with reference to the drawings.
First, the structure of the stirring apparatus A which concerns on one Embodiment of this invention is demonstrated with reference to FIG.
FIG. 1 is a side view showing the overall configuration of the stirring apparatus A according to the present embodiment.

As shown in FIG. 1, the stirring device A according to the present embodiment is used as a culture tank for cultivating animal and plant cells.
The stirrer A includes a storage tank 1 that stores liquid, an air supply unit 2 that supplies gas into the liquid, a stirring unit 3 that stirs the liquid, a drive unit 4 that rotates the stirring unit 3, and a plurality of units. Baffle plate 5.

 The storage tank 1 is a container having a substantially cylindrical shape with a bottom and a lower end having a substantially spherical curved surface, in which a liquid M is stored. The liquid M is a culture solution containing animal and plant cells to be cultured and various nutrients necessary for culturing the cells.

The air supply unit 2 includes a ring sparger 21 provided at a lower portion in the storage tank 1 and a gas supply device 22 that supplies gas to the ring sparger 21.
The ring sparger 21 has a shape in which a tube having a large number of holes on the surface thereof is arranged in a substantially annular shape, and injects the gas supplied from the gas supply device 22 from the holes.
The gas supply machine 22 is a pump that supplies air to the ring sparger 21.

The stirring unit 3 includes a drive shaft 31 that hangs down substantially in the center of the storage tank 1 and a stirring blade 32 that is integrally connected to the lower end of the drive shaft 31.
The drive shaft 31 is a rod-like member extending in the vertical direction, and an upper end portion thereof is connected to the drive unit 4 described later so as to be rotatable around the shaft.
The stirring blade 32 is provided with a plurality of flat blades radially around the drive shaft 31, and all the blades are parallel to the axial direction of the drive shaft 31.

 The drive unit 4 is provided above the storage tank 1 and is integrally connected to the upper end of the drive shaft 31. The drive unit 4 is an electric motor that rotates the drive shaft 31 around the axis.

 The baffle plate 5 is a belt-like flat plate that extends in two directions inside the side wall of the storage tank 1 in the vertical direction and is orthogonal to the inner peripheral surface of the storage tank 1. The two baffle plates 5 are provided at substantially equal intervals in the circumferential direction of the storage tank 1 in order to make stirring uniform.

Then, operation | movement and an effect | action of the stirring apparatus A which concern on this embodiment are demonstrated.
First, the stirring of the liquid M by the stirring unit 3 and the baffle plate 5 will be described, and then the infusion of oxygen supplied by the air supply unit 2 into the liquid M will be described.

The drive unit 4 rotates the drive shaft 31 and the stirring blade 32 of the stirring unit 3. As the stirring blade 32 rotates, the liquid M rotates in the circumferential direction and is stirred. As the liquid M is agitated, the oxygen transfer capacity coefficient (KLa) of the liquid M increases.
Since the baffle plate 5 is erected perpendicularly to the flow in the stirring direction of the liquid M, the flow in the stirring direction is converted into other directions such as the vertical direction and the radial direction, and the liquid M is further stirred. Therefore, KLa further increases.

Next, infiltration of oxygen supplied to the liquid M by the air supply unit 2 will be described.
Along with the operation of the stirring unit 3, the gas supply unit 22 of the air supply unit 2 supplies a gas (air) containing oxygen to the ring sparger 21. The ring sparger 21 injects the supplied air from a hole provided on the surface thereof. The jetted air becomes bubbles in the liquid M, and the bubbles and the liquid M are both stirred by the stirring unit 3.
The bubbles contain oxygen, and the bubbles and the liquid M are stirred together, so that the oxygen is dissolved into the liquid M. Here, since the dissolved oxygen concentration depends on KLa, the dissolved oxygen concentration is maintained at a high value when KLa is increasing.
As described above, the value of KLa can be increased by appropriately setting the specifications of the baffle plate.

 On the other hand, when the specifications of the baffle plate are set so that the flow conversion by the baffle plate is reduced, the stirring is not promoted, so that the rise due to the action of the KLa baffle plate does not occur. As described above, in this embodiment, KLa can be maintained at an appropriate value by changing the specifications of the baffle plate.

Next, the range in which the ratio of the width of the baffle plate 5 to the width of the storage tank 1 and the value of KLa have a substantially linear relationship will be described.
The ratio Wb / D of the width Wb (see FIG. 1) of the baffle plate 5 to the width D (see FIG. 1) of the storage tank 1 was changed, and the KLa of the liquid M in each case was actually measured.

First, measurement conditions will be described.
The width D of the storage tank 1 was 0.5 m, the depth was 0.4 m, and the depth of the liquid M was 0.3 m. The amount of the liquid M is about 60 L (liter). The number of baffle plates 5 was two or four, and the stirring blades 32 were disk turbine blades or pitch paddle blades. The stirring rotation speed of the stirring unit 3 was 50 rpm, and the amount of air supplied from the ring sparger 21 was 6.0 L / min. The KLa of the liquid M was measured by the gassing-out method. In addition, the power at the time of stirring was measured by the shaft torque value.

また、表１に示した結果を、図２に示した。図２は、邪魔板５の枚数が２枚、攪拌翼３２がディスクタービン翼のときの、比率Ｗｂ／Ｄと、ＫＬａ及び攪拌動力との関係を示す概略図である。 First, the ratio Wb / D of the width Wb of the baffle plate 5 to the width D of the storage tank 1, the KLa of the liquid M, and the stirring power when the number of the baffle plates 5 is two and the stirring blade 32 is a disk turbine blade. Table 1 shows the relationship. The value of the width Wb of the baffle plate 5 is also described.

The results shown in Table 1 are shown in FIG. FIG. 2 is a schematic diagram showing the relationship between the ratio Wb / D, KLa, and stirring power when the number of baffle plates 5 is two and the stirring blade 32 is a disc turbine blade.

As shown in Table 1 and FIG. 2, when the value of Wb / D is in the range from 0.07 to 0.12, the value of KLa is almost the maximum value, and as the value deviates from the range, the value of KLa is It gradually decreased. Therefore, by appropriately setting the value of Wb / D, a value of about 10 [h ⁻¹ ] can be secured as the maximum KLa.
Moreover, when the value of Wb / D is 0.15 or more, the stirring power increases rapidly. Therefore, by setting the value of Wb / D to 0.05 or less, a low KLa can be ensured without increasing the stirring power.

From the above, when the value of Wb / D is in the range of 0.12 or less, KLa increases substantially according to the value of Wb / D, and therefore KLa is changed from approximately 6.0 [h ⁻¹ ] to 11 [h. ⁻¹ ] and can be maintained at an appropriate value.
In addition, even when the stirring rotation speed was set to 10, 20, 100, 150, and 200 rpm, the same result as the above result was obtained.

また、表２に示した結果を、図３に示した。図３は、邪魔板５の枚数が２枚、攪拌翼３２がピッチパドル翼のときの、比率Ｗｂ／Ｄと、ＫＬａ及び攪拌動力との関係を示す概略図である。 Next, when the number of baffle plates 5 is two and the stirring blade 32 is a pitch paddle blade, the ratio Wb / D of the width Wb of the baffle plate 5 to the width D of the storage tank 1, the KLa of the liquid M, and the stirring Table 2 shows the relationship with power. The value of the width Wb of the baffle plate 5 is also described.

The results shown in Table 2 are shown in FIG. FIG. 3 is a schematic diagram showing the relationship between the ratio Wb / D, KLa, and stirring power when the number of baffle plates 5 is two and the stirring blade 32 is a pitch paddle blade.

As shown in Table 2 and FIG. 3, when the value of Wb / D is in the range from 0.07 to 0.12, the value of KLa is almost the maximum value, and as the value deviates from the range, the value of KLa is It gradually decreased. Therefore, by appropriately setting the value of Wb / D, a value of about 10 [h ⁻¹ ] can be secured as the maximum KLa.
Moreover, when the value of Wb / D is 0.15 or more, the stirring power increases rapidly. Therefore, by setting the value of Wb / D to 0.05 or less, a low KLa can be ensured without increasing the stirring power.

From the above, when the value of Wb / D is in the range of 0.12 or less, KLa increases substantially according to the value of Wb / D. Therefore, KLa is changed from approximately 4.5 [h ⁻¹ ] to 11 [h ⁻¹ ] and can be maintained at an appropriate value.
In addition, even when the stirring rotation speed was set to 10, 20, 100, 150, and 200 rpm, the same result as the above result was obtained.

また、表３に示した結果を、図４に示した。図４は、邪魔板５の枚数が４枚、攪拌翼３２がディスクタービン翼のときの、比率Ｗｂ／Ｄと、ＫＬａ及び攪拌動力との関係を示す概略図である。 Further, the ratio Wb / D of the width Wb of the baffle plate 5 to the width D of the storage tank 1, the KLa of the liquid M, and the stirring power when the number of the baffle plates 5 is 4 and the stirring blade 32 is a disk turbine blade. Table 3 shows the relationship. The value of the width Wb of the baffle plate 5 is also described.

The results shown in Table 3 are shown in FIG. FIG. 4 is a schematic view showing the relationship between the ratio Wb / D, KLa, and stirring power when the number of baffle plates 5 is four and the stirring blade 32 is a disc turbine blade.

As shown in Table 3 and FIG. 4, when the value of Wb / D is in the range from 0.07 to 0.12, the value of KLa is almost the maximum value, and as the value deviates from the range, the value of KLa is It gradually decreased. Therefore, by appropriately setting the value of Wb / D, a value of about 10 [h ⁻¹ ] can be secured as the maximum KLa.
Moreover, when the value of Wb / D is 0.12 or more, the stirring power increases rapidly. Therefore, by setting the value of Wb / D to 0.05 or less, a low KLa can be ensured without increasing the stirring power.

From the above, when the value of Wb / D is in the range of 0.12 or less, KLa increases substantially according to the value of Wb / D, and therefore KLa is changed from approximately 7.5 [h ⁻¹ ] to 11 [h ⁻¹ ] and can be maintained at an appropriate value.
In addition, even when the stirring rotation speed was set to 10, 20, 100, 150, and 200 rpm, the same result as the above result was obtained.

In the above measurement test, the supply amount of air is 6.0 L / min. However, the supply amount may be increased or decreased within a range in which cell death does not occur. Since KLa is only proportional to the 0.4 to 0.7th power of the oxygen supply amount, the value of Wb / D for deriving the maximum value of KLa does not change even if the air supply amount is changed. The above results are the same when the gas to be supplied is not air but oxygen.
Further, in the above actual measurement test, the number of baffle plates 5 is two or four, but other plural numbers may be used. For example, even when six baffle plates 5 are used, the same tendency as in the above test can be obtained.
Furthermore, in the above-described actual measurement test, the stirring blade 32 used was a disk turbine blade and a pitch paddle blade, but other types of stirring blades, such as propeller blades and elephant blades, can obtain the same tendency as in the above test.

Therefore, according to the present embodiment, the following effects can be obtained.
According to the present embodiment, KLa can be adjusted within a predetermined range even under conditions in which the number of stirring rotations and the amount of oxygen supply cannot be easily increased due to the characteristics of objects existing in the storage tank 1, and to an appropriate value. There is an effect that can be maintained.

 Note that the operation procedures shown in the above-described embodiment, or the shapes and combinations of the components are examples, and can be variously changed based on process conditions, design requirements, and the like without departing from the gist of the present invention. is there.

For example, the baffle plate 5 in the above embodiment may be detachable from the storage tank 1. Furthermore, it is good also as a structure which can select and install the baffle plate 5 of suitable width | variety based on KLa of the liquid M set according to the kind of animal and plant cell to culture | cultivate.
By adopting such a configuration, appropriate KLa can be ensured even in different types of cell culture.

 Moreover, although the air supply part 2 in the said embodiment has the ring sparger 21, this invention is not limited to such a structure, The polymer for spiral sparger, an air stone, or a microbubble discharge | release It may be a body or the like.

Moreover, in the said embodiment, although the stirring apparatus A is used for culture | cultivation of animal and plant cells, this invention is not limited to such a use, You may use for culture | cultivation of microorganisms.
Moreover, you may use not only the stirring apparatus A as a culture tank but as a reaction tank which performs the chemical reaction etc. which require oxygen at the time of reaction.

It is a side view which shows the whole structure of the stirring apparatus A which concerns on this embodiment. It is the schematic which shows the relationship between ratio Wb / D, KLa, and stirring power when the number of the baffle plates 5 is 2 and the stirring blade 32 is a disk turbine blade. It is the schematic which shows the relationship between ratio Wb / D, KLa, and stirring power when the number of the baffle plates 5 is 2 and the stirring blade 32 is a pitch paddle blade. It is the schematic which shows the relationship between ratio Wb / D, KLa, and stirring power when the number of the baffle plates 5 is 4 and the stirring blade 32 is a disk turbine blade.

Explanation of symbols

A ... Stirrer, 1 ... Storage tank, 2 ... Air supply unit, 3 ... Stirrer unit, 5 ... Baffle plate

Claims (5)

A storage tank that has a substantially cylindrical shape and stores liquid;
An air supply unit for supplying a gas containing oxygen into the liquid;
A stirring unit provided in the storage tank and stirring the liquid;
A baffle plate provided inside the side wall of the storage tank and converting the flow of the liquid from the stirring direction by the stirring unit to another direction,
Based on the oxygen transfer capacity coefficient of the liquid, the specification of the baffle plate is set.  The stirring device according to claim 1, wherein a ratio of the width of the baffle plate to the width of the storage tank is set based on the set oxygen transfer capacity coefficient.  The stirring device according to claim 2, wherein a ratio of the width of the baffle plate to the width of the storage tank is 0.12 or less.  The stirrer according to any one of claims 1 to 3, wherein a plurality of the baffle plates are provided at substantially equal intervals in the circumferential direction of the storage tank. The stirrer according to any one of claims 1 to 4, wherein animal and plant cells or microorganisms are cultured in the liquid.

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