Stirring device

Abstract

To provide a stirring device which has a mechanism that can stably supply a processing object to a homogenizer.SOLUTION: A stirring device includes: a stirring tank 1 which stores a processing object; a stirring blade 2 which has a rotary drive shaft 2a that extends in the vertical direction and a vane part 2b that is provided in the rotary drive shaft 2a, and stirs the processing object by the rotation of the vane part 2b following the rotation of the rotary drive shaft 2a; a homogenizer 3 which is arranged on the lower side of the rotary drive shaft 2a, has a stator and a rotor that are arranged concentrically and performs suction and extrusion of the processing object with the turbulence effect following the rotation of the rotor; and a feed blade 8 which is provided on a lower end part of the rotary drive shaft 2a, rotates following the rotation of the rotary drive shaft 2a and pressure-feeds the processing object to the homogenizer 3.SELECTED DRAWING: Figure 1

Description

Technical Field

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[0001] The present invention relates to a stirring device used for treating viscous liquids, powders, and other objects to be treated, such as mixing, emulsifying, dispersing, and defoaming, in the manufacturing processes of pharmaceuticals, cosmetics, battery materials, fine chemicals, foods, and the like.

Background Art

[0002] For example, in order to perform processes such as mixing, dispersing, emulsifying, and defoaming of the object to be treated, stirring devices as described in Patent Documents 1 and 2 are used. These stirring devices are mainly composed of a stirring tank for accommodating the object to be treated, a stirring blade for stirring the object to be treated in the stirring tank, and a homogenizer disposed at the lower part of the stirring tank. The homogenizer has a comb-tooth-shaped stator and rotor arranged concentrically, sucks in and extrudes the object to be treated due to the turbulence effect accompanying the rotation of the rotor, and promotes the mixing, dispersion, emulsification, etc. of the object to be treated by the shearing action at that time.

[0003] Also, Patent Documents 3 to 5 describe a technique in which a rotating blade such as an impeller or a screw is provided on the rotor rotation axis of the homogenizer, and the object to be treated is pressure-fed toward the homogenizer by the rotating blade that rotates together with the rotor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0005] When the viscosity of the material being processed increases, the suction action of the homogenizer alone may be insufficient to supply the material to the homogenizer, leading to a decrease in processing efficiency. Furthermore, depending on the viscosity of the material being processed, it may not be supplied to the homogenizer at all, resulting in a complete inability to process.

[0006] To avoid the above-mentioned situation, one might consider providing a rotating blade, as described in Patent Documents 3-5, to pressurize the material to be processed into a homogenizer. However, the feed blades in Patent Documents 3-5 are mounted on the rotor rotation axis of the homogenizer and rotate at high speed at the same rotational speed (rpm) as the homogenizer (rotor) (the rotational speed of the homogenizer is considerably higher than that of the stirring blades). As a result, the supply flow rate of the material to be processed into the homogenizer may exceed the processing limit of the homogenizer (the maximum flow rate of material that the homogenizer can suck in and push out per unit time), disrupting the stable suction and push-out action of the homogenizer and preventing the required shearing action from being applied to the material. Furthermore, with high-viscosity materials, the flow of the material may not keep up with the high-speed rotation of the rotating blade, causing the blade to idle, resulting in an insufficient supply flow rate of the material to the homogenizer, or even no material being supplied to the homogenizer at all.

[0007] The object of the present invention is to provide a stirring device equipped with a mechanism that can stably supply the material to be processed to a homogenizer. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides an agitation device comprising: an agitation tank for containing a material to be processed; a rotary drive shaft extending in the vertical direction; a stirring blade having a blade portion provided on the rotary drive shaft, which agitates the material to be processed by the rotation of the blade portion in conjunction with the rotation of the rotary drive shaft; and a homogenizer having a stator and rotor arranged concentrically below the rotary drive shaft, which sucks in and pushes out the material to be processed by the turbulence effect associated with the rotation of the rotor, wherein a feed blade is provided at the lower end of the rotary drive shaft, which rotates in conjunction with the rotation of the rotary drive shaft and pressurizes the material to be processed toward the homogenizer. [Effects of the Invention]

[0009] According to the present invention, a feed blade provided at the lower end of the rotation drive shaft of the stirring blade rotates at the same rotational speed as the rotation drive shaft, and pressurizes the material to be processed toward the homogenizer. This prevents the supply flow rate of the material to be processed toward the homogenizer from being excessive or insufficient, and makes it possible to stably supply the material to the homogenizer. [Brief explanation of the drawing]

[0010] [Figure 1] This is a longitudinal cross-sectional view showing the overall configuration of the stirring device according to the first embodiment. [Figure 2] This is a side view of the feed blade of the stirring device according to the first embodiment. [Figure 3] This is a longitudinal cross-sectional view showing the overall configuration of the stirring device according to the second embodiment. [Figure 4A] This is a view from above of the feed blade of the stirring device according to the second embodiment. [Figure 4B] This is a view of the feed blade of the stirring device according to the second embodiment, seen from diagonally below. [Figure 4C] This is a partial cross-sectional view of the feed blade of the stirring device according to the second embodiment, as seen from the direction of line bb in Figure 4A. [Figure 5] This is a longitudinal cross-sectional view showing the overall configuration of the stirring device according to the third embodiment. [Figure 6]It is a diagram showing the relationship between the rotational speed (rpm) of the stirring blade and the supply flow rate of the object to be processed to the homogenizer. [Figure 7] It is a diagram showing the relationship between the rotational speed (rpm) of the homogenizer and the supply flow rate of the object to be processed to the homogenizer.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0012] FIG. 1 is a longitudinal sectional view showing the overall configuration of a stirring device according to a first embodiment. The stirring device of this embodiment is mainly composed of a stirring tank 1 for accommodating the object to be processed, a stirring blade 2 and a homogenizer 3 provided inside the stirring tank 1.

[0013] A circulation pipe 4 is disposed between the bottom and the side of the stirring tank 1. A part of the circulation pipe 4 is connected to a discharge pipe 4b via an openable and closable discharge valve 4a. Further, a baffle 5 is fixedly arranged inside the stirring tank 1.

[0014] The stirring blade 2 is composed of a rotation drive shaft 2a that extends in the vertical direction along the central part of the stirring tank 1 and is rotatable around its central axis X, and a blade part 2b provided on the rotation drive shaft 2a. The blade part 2b includes a first blade 2b1 attached to an intermediate part of the rotation drive shaft 2a and a second blade 2b2 attached to the lower end part of the rotation drive shaft 2. The second blade 2b2 extends in the outer peripheral direction from a plurality of positions at the lower end part of the rotation drive shaft 2 and further extends toward the upper part of the stirring tank 1. Further, a scraper 2b3 for scraping the object to be processed adhering to the inner wall of the stirring tank 1 is attached to the second blade 2b2. The rotation drive shaft 2a is rotationally driven around the central axis X by a drive motor (not shown), and as the blade part 2b rotates with the rotation of the rotation drive shaft 2a, the object to be processed in the stirring tank 1 is stirred.

[0015] The homogenizer 3 is disposed below the lower side of the rotary drive shaft 2a. As is well known, it has a comb-shaped stator and rotor arranged concentrically, and sucks in and extrudes the object to be processed by the turbulence effect accompanying the rotation of the rotor. The rotor is rotationally driven about an axis coaxial with the central axis X of the rotary drive shaft 2a by a drive motor not shown in the figure.

[0016] In this embodiment, the rotary drive shaft 2a is formed in a hollow shaft shape, and the raw material supply pipe 7 is inserted therein along the central axis X of the rotary drive shaft 2a. The upper end portion (not shown) of the raw material supply pipe 7 communicates with a raw material input portion (not shown) such as a hopper disposed above the outside of the stirring tank 1, and the lower end portion 7a of the raw material supply pipe 7 penetrates the lower end portion of the rotary drive shaft 2a and extends downward, facing the central portion of the homogenizer 3 with a predetermined gap therebetween. The raw material (powder, liquid, mixture thereof, etc.) introduced into the raw material supply pipe 7 from a raw material input portion not shown descends inside the raw material supply pipe 7 and is discharged directly above the central portion of the homogenizer 3 from the lower end of the lower end portion 7a, and is sucked into the homogenizer 3 by the turbulence effect accompanying the rotation of the homogenizer 3 (rotor). The raw material input into the stirring tank 1 via the raw material supply pipe 7 is performed when initially introducing the raw material into the stirring tank 1 or when additionally introducing the raw material to the object to be processed being processed in the stirring tank 1. The raw material supply pipe 7 may rotate with the rotary drive shaft 2a or may not rotate.

[0017] Furthermore, a feed blade 8 is provided at the lower end of the rotary drive shaft 2a. As shown in an enlarged view in Figure 2, in this embodiment, the feed blade 8 comprises a ring-shaped mounting portion 8a attached to the lower end of the rotary drive shaft 2a by appropriate fixing means such as a screw, and a blade portion 8b, one end 8b1 of which is fixed to the mounting portion 8a, and which extends spirally from the one end 8b1 toward the other end 8b2 on the lower side. The blade portion 8b is formed by spirally molding a strip-shaped member made of metal or resin, and has an upper surface 8b3 facing upward and a lower surface 8b4 facing downward. With the feed blade 8 attached to the lower end of the rotary drive shaft 2a, the blade portion 8b extends downward, spirally encircling the lower end 7a of the raw material supply pipe 7, which extends downward through the rotary drive shaft 2a and the attachment portion 8a, from the outer circumference side with a predetermined gap δ (the gap between the outer circumference of the lower end 7a and the inner circumference of the blade portion 8b), and the other end 8b2 is located slightly above the lower end of the lower end 7a. When the rotary drive shaft 2a rotates clockwise when viewed from above (in the direction of the arrow R in the figure), the feed blade 8 rotates clockwise R in conjunction with the rotation of the rotary drive shaft 2a. This rotation of the feed blade 8 pushes the material to be processed in the agitated tank 1 with the lower surface 8b4 of the blade portion 8b, and pressurizes it downward.

[0018] The processing of the material to be processed in the agitated tank 1 is carried out by rotating the agitator blade 2 (rotary drive shaft 2a) and the homogenizer 3 (rotor). The rotation speed (rpm) of the agitator blade 2 is set to a considerably lower rotation speed (rpm) than that of the homogenizer 3. The rotation of the agitator blade 2 agitates the material to be processed in the agitated tank 1. At the same time, the feed blade 8, which is provided at the lower end of the rotary drive shaft 2a, rotates at the same rotation speed as the agitator blade 2, so that the material to be processed in the agitated tank 1 is pushed downward by the helical blade portion 8b of the feed blade 8 and pumped towards the homogenizer 3. The material to be processed, which has been pumped downward by the feed blade 8 and has reached the vicinity of the homogenizer 3, is drawn into the homogenizer 3 by the turbulence effect caused by the rotation of the homogenizer 3 (rotor). The material to be processed, after being mixed, emulsified, and dispersed in the homogenizer 3, is pushed out of the homogenizer 3 into the circulation pipe 4 and returned to the inside of the stirring tank 1 via the circulation pipe 4. The material returned to the inside of the stirring tank 1 is stirred by the stirring blades 2 and pumped downwards by the feed blades 8 and sucked back into the homogenizer 3. After the processing of the material is complete, the material pushed out of the homogenizer 3 is discharged as a product from the discharge pipe 4b (with the discharge valve 4a open) connected to the circulation pipe 4.

[0019] Figure 3 is a longitudinal cross-sectional view showing the overall configuration of the stirring device according to the second embodiment. The difference between the stirring device according to the second embodiment and the stirring device according to the first embodiment described above is that a feed blade 18, which has a different configuration from the feed blade 8, is provided at the lower end of the rotary drive shaft 2a.

[0020] As shown in Figures 4A to 4C, the feed blade 18 used in the second embodiment comprises a ring-shaped mounting portion 18a attached to the lower end of the rotary drive shaft 2a by appropriate fixing means such as screws, a plurality of support rods 18b fixed to the mounting portion 18a, for example four support rods 18b, and a plurality of block-shaped blade portions 18c attached to the support rods 18b. Each blade portion 18c is formed in the same shape from a metal or resin material, and both sides in the circumferential direction are fixed to two circumferentially adjacent support rods 18b. Between the circumferentially adjacent support rods 18b, there are a plurality of sets of blade portions 18c arranged vertically, for example four sets of blade portions 18c arranged at equal intervals along the circumferential direction. The sets of circumferentially adjacent blade portions 18c are arranged with the positions of the blade portions 18c shifted vertically between them. With the feed blade 18 attached to the lower end of the rotary drive shaft 2a (see Figure 3), the set of blade sections 18c surrounds the lower end 7a of the raw material supply pipe 7, which extends downward through the lower end of the rotary drive shaft 2a and the attachment section 18a, from the outer circumference side with a predetermined gap (the gap between the outer circumference of the lower end 7a and the inner circumference of the blade section 18c), and the lowest blade section 18c is located slightly above the lower end of the lower end 7a.

[0021] As shown in Figure 4B, each blade portion 18c has a first side surface 18c1 on one side in the circumferential direction and a second side surface 18c2 on the other side in the circumferential direction. The first side surface 18c1, located on the front side in the right rotation direction (arrow direction R) when viewed from above, is formed as an inclined surface (inclined plane or inclined curved surface) that slopes forward in the right rotation direction R from its lower end to its upper end, and the second side surface 18c2, located on the front side in the left rotation direction (arrow direction L), is formed as an inclined surface (inclined plane or inclined curved surface) that slopes forward in the left rotation direction L from its lower end to its upper end. Therefore, when the rotation drive shaft 2a rotates in the right rotation direction R, and the feed blade 18 rotates in the right rotation direction R as the rotation drive shaft 2a rotates, the material to be processed in the stirring tank 1 is pushed downward by the first side surface 18c1 on the front side in the rotation direction of each blade portion 18c. Furthermore, when the rotary drive shaft 2a rotates in the leftward direction L, and the feed vanes 18 rotate in the leftward direction L in conjunction with the rotation of the rotary drive shaft 2a, the material to be processed in the agitated tank 1 is pushed downward by the second side surface 18c2 on the forward side in the direction of rotation of each vane portion 18c. Therefore, in the agitator according to the second embodiment, in which the feed vanes 18 are provided at the lower end of the rotary drive shaft 2a, the material to be processed in the agitated tank 1 can be pumped toward the homogenizer 3 regardless of whether the rotary drive shaft 2a rotates to the left or right. Other matters are the same as in the first embodiment, so redundant explanations will be omitted.

[0022] Figure 5 is a longitudinal cross-sectional view showing the overall configuration of the stirring device according to the third embodiment. The difference between the stirring device according to the third embodiment and the stirring device according to the first embodiment described above is that the raw material supply pipe 7 inserted inside the rotary drive shaft 2a has been eliminated. By eliminating the raw material supply pipe 7, the inner circumference of the blade portion 8b of the feed blade 8 becomes hollow. Raw materials are introduced into the stirring tank 1, for example, by installing a raw material supply valve on the lower side of the stirring tank 1 and introducing the raw materials from the raw material supply valve to a position directly above the homogenizer 3.

[0023] In the first embodiment of the agitator shown in Figure 1, the lower end 7a of the raw material supply pipe 7 is positioned on the inner circumference side of the blade portion 8b of the feed blade 8. In contrast, in the third embodiment of the agitator shown in Figure 5, the inner circumference side of the blade portion 8b of the feed blade 8 is hollow. Comparing the two, it can be said that the agitator of the first embodiment has a higher pumping effect of the material to be processed by the feed blade 8 compared to the agitator of the third embodiment. This is thought to be because, when the inner circumference side of the blade portion 8b is hollow, a phenomenon occurs in which some of the material to be processed that is pumped downward by the blade portion 8b flows back upward through the inner circumference side of the blade portion 8b. By positioning an axial member such as the lower end 7a of the raw material supply pipe 7 on the inner circumference side of the blade portion 8b of the feed blade 8, the above backflow phenomenon is suppressed by the axial member, and the material to be processed is pumped more effectively. Taking these circumstances into consideration, in the configuration in which the raw material supply pipe 7 is eliminated, the axial member arranged on the inner circumference side of the blade portion 8b may be integrally formed with the lower end of the rotary drive shaft 2a.

[0024] Although not shown in the illustration, the stirring apparatus according to the second embodiment shown in Figure 3 may also have a configuration in which the raw material supply pipe 7 is eliminated, similar to the above. [Examples]

[0025] A comparative test was conducted using the stirring device according to the first embodiment (example) shown in Figure 1 and a comparative example stirring device obtained by removing the feed blade 8 from the stirring device of the first embodiment. The comparative test was performed by operating the stirring device under the conditions shown in Tables 1 to 3 below {viscosity of the material to be processed (mPa·s), rotational speed of the stirring blade 2 (rotating drive shaft 2a) (rpm), rotational speed of the homogenizer 3 (rotor) (rpm)} and measuring the flow rate (L / min) of the material to be processed discharged from the homogenizer 3 (the material to be pushed out from the homogenizer 3 and discharged from the discharge pipe 4b). The flow rate (L / min) of the material to be processed discharged from the homogenizer 3 can be considered equivalent to the supply flow rate (L / min) of the material to be processed to the homogenizer 3.

[0026] [Table 1]

[0027] [Table 2]

[0028] [Table 3]

[0029] As shown in Tables 1 and 2, when compared under the same conditions, it was confirmed that the stirring apparatus in the embodiment equipped with feed vanes increased the flow rate of the material to be processed to the homogenizer compared to the stirring apparatus in the comparative example without feed vanes. This increase in the flow rate of the material to be processed to the homogenizer is due to the pumping force exerted by the feed vanes, which rotate in conjunction with the rotation of the stirring vanes (rotary drive shaft), pushing the material towards the homogenizer. Furthermore, it was confirmed that increasing the rotation speed of the stirring vanes in the stirring apparatus equipped with feed vanes also increased the flow rate of the material to be processed to the homogenizer.

[0030] The tests shown in Table 3 used a high-viscosity cream with a viscosity of 300,000 MPa·s as the material to be processed. In the comparative example's stirring device, which did not have a feed vane, the supply flow rate (g / min) of the material to be processed to the homogenizer was zero, making processing impossible. In contrast, the stirring device of the example equipped with a feed vane was able to stably supply the material to the homogenizer. From these test results, it was confirmed that the stirring device of the example equipped with a feed vane is capable of stable processing even with high-viscosity materials such as 300,000 MPa·s. Furthermore, as shown in Figure 6, it was confirmed that the supply flow rate of the material to be processed to the homogenizer is proportional to the rotation speed of the stirring vane (= rotation speed of the feed vane).

[0031] The tests shown in Table 4 below used the same high-viscosity cream as the tests shown in Table 3, and were conducted in a stirring apparatus equipped with feed blades, while keeping the rotation speed of the feed blades constant and varying the rotation speed of the homogenizer. As shown in Figure 7, it was confirmed that the supply flow rate (g / min) of the material to be processed to the homogenizer increased exponentially and rapidly in response to the increase in the rotation speed of the homogenizer.

[0032] [Table 4]

[0033] Generally, the shear force of a homogenizer acting on a material being processed is proportional to the homogenizer's rotational speed (rpm), provided that the viscosity of the material and the homogenizer's configuration (including the clearance between the rotor and stator) are the same. While the test results in Table 4 (Figure 7) show that adjusting the homogenizer's rotational speed can adjust the supply flow rate of the material to the homogenizer, it is difficult to adjust to a desired flow rate because the supply flow rate changes exponentially and rapidly with respect to the homogenizer's rotational speed. Furthermore, changing the homogenizer's rotational speed alters the shear force acting on the material, affecting the processing quality. In contrast, in the stirring apparatus of the embodiment equipped with a feed vane, as shown in the test results in Table 3 (Figure 6), the supply flow rate of the material to the homogenizer changes proportionally to the rotational speed of the stirring vane, making it easier to adjust to a desired flow rate. Additionally, since there is no need to change the homogenizer's rotational speed when adjusting the supply flow rate, the shear force acting on the material can be maintained at a desired value. [Explanation of Symbols]

[0034] 1. Agitation tank 2 stirring blades 2a Rotary drive shaft 2b wing 3. Homogenizer 7 Raw material supply pipe 7a Lower end 8 Feed Wings 8a Mounting part 8b wing section 18 Feed Wing 18a Mounting part 18b Support rod 18c wing 18c1 1st side 18c2 2nd side δ gap

Claims

1. A stirring tank containing the material to be processed, A stirring blade having a rotating drive shaft extending in the vertical direction and a blade portion provided on the rotating drive shaft, the stirring blade agitates the material to be processed by the rotation of the blade portion in conjunction with the rotation of the rotating drive shaft, A homogenizer having a stator and rotor arranged concentrically below the aforementioned rotary drive shaft, which sucks in and pushes out the material to be processed by the turbulence effect caused by the rotation of the rotor, In a stirring device equipped with, A stirring device characterized in that a feed blade is provided at the lower end of the rotary drive shaft, which rotates in conjunction with the rotation of the rotary drive shaft and pressurizes the material to be processed toward the homogenizer.

2. The stirring device according to claim 1, wherein the feed blade has a blade portion that extends spirally from above to below.

3. The stirring device according to claim 1, wherein the feed blade has a plurality of blade portions arranged at predetermined intervals in the circumferential direction, and each blade portion has a first side surface that is located on the front side in the direction of rotation with respect to rotation in one direction of the rotary drive shaft and is formed as an inclined surface that slopes forward in the direction of rotation from the lower end to the upper end, and a second side surface that is located on the front side in the direction of rotation with respect to rotation in the other direction of the rotary drive shaft and is formed as an inclined surface that slopes forward in the direction of rotation from the lower end to the upper end.

4. The stirring device according to claim 2 or 3, wherein a shaft-shaped member extending in the vertical direction is arranged on the inner circumference side of the blade portion of the feed blade with a predetermined gap between them.

5. The stirring device according to claim 4, further comprising a raw material supply pipe inserted coaxially inside the rotary drive shaft, wherein the lower end of the raw material supply pipe extends downward through the lower end of the rotary drive shaft and is arranged as the shaft-shaped member on the inner circumference side of the blade portion of the feed blade.

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