JP2022063988A - Mixer - Google Patents

Abstract

To provide a mixer capable of further promoting a circulation flow in a mixing tank and further shortening a mixing time.SOLUTION: A mixer includes a mixing shaft 10 vertically installed in a mixing tank 100 in a rotatable manner, a lower stage mixing wing 20 installed at the lower end part of the mixing shaft 10, and an upper stage mixing wing 30 having a blade 31 arranged along the mixing shaft at a distance from the mixing shaft 10 and installed at a higher position than the lower stage mixing wing 20 of the mixing shaft 10. The blade 31 of the upper stage mixing wing 30 has a twisted part 34, which is twisted so that the lower end side thereof rotates in a reverse direction to a rotation direction of the mixing shaft 10 relative to the upper end side.SELECTED DRAWING: Figure 1

Description

The present invention relates to a stirrer for stirring a fluid in a stirrer, and more particularly to a stirrer suitable for stirring a viscous fluid having a relatively high viscosity.

Conventionally, as a stirring device used for stirring a fluid, for example, dispersion mixing or dissolution mixing of a viscous fluid such as a viscous beverage or a viscous food, a stirring shaft erected in a stirring tank and a stirring shaft are attached. It is generally known that the stirring blade is provided and the stirring blade is rotated together with the stirring shaft to generate a circulating flow in the fluid in the stirring tank to stir the fluid.

Here, as the stirring blade, various shapes depending on the characteristics of the fluid to be agitated and the like have been proposed, and for example, there are ones called anchor paddles, gate paddles, and bottom paddles. Each of these stirring blades is provided with a plurality of blade plates extending radially from the stirring shaft, and the blade plates cause a circulating flow in the fluid when the stirring shaft rotates.

Further, as a stirring device, there is a stirring blade in which stirring blades are attached in multiple stages in the vertical direction with respect to the stirring shaft. For example, there are those in which a lower stirring blade and an upper stirring blade are mounted on a stirring shaft suspended in the center of the stirring tank (see Patent Documents 1 and 2 and the like).

According to the stirring device described in Patent Documents 1, 2 and the like, the circulating flow formed in the stirring tank can be promoted and the stirring efficiency of the fluid in the stirring tank is improved, so that the stirring time can be shortened more than before. Can be done.

Japanese Unexamined Patent Publication No. 7-124456 Japanese Patent No. 501428

However, even in a stirring device provided with a lower stirring blade and an upper stirring blade mounted on a stirring shaft as described in Patent Documents 1, 2 and the like, the circulating flow can be sufficiently flowed depending on the characteristics of the fluid to be stirred. It may not be possible to promote it. For example, when the fluid to be agitated is a viscous fluid having a relatively high viscosity and difficult to flow, it is difficult to promote the circulating flow even with the above configuration, and the agitation time cannot be sufficiently shortened. There is also.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a stirring device capable of further promoting the circulating flow in the stirring tank and further shortening the stirring time.

One aspect of the present invention that solves the above problems is a stirring shaft rotatably installed in a stirring tank.
It has a lower stirring blade attached to the lower end of the stirring shaft and a blade plate arranged along the stirring shaft away from the stirring shaft, and is above the lower stirring blade of the stirring shaft. The blade plate of the upper stage stirring blade is provided with an upper stage stirring blade to be attached, and the blade plate of the upper stage stirring blade is a twisted portion twisted so that the lower end side thereof rotates in the direction opposite to the rotation direction of the stirring shaft with respect to the upper end side. It is in the stirring device characterized by having.

Here, it is preferable that the blade plate of the upper stirring blade is arranged so as to be inclined so that the upper end side thereof approaches the stirring shaft.

Further, it is preferable that the blade plate of the upper stirring blade is inclined in the range of 10 to 15 ° with respect to the stirring axis.

Further, it is preferable that each blade plate of the upper stirring blade is arranged directly above the lower stirring blade.

Further, it is preferable that the blade plate of the upper stirring blade is arranged so that the surface direction at the upper end of the twisted portion is orthogonal to the rotation direction of the stirring shaft.

Further, it is preferable that the twisted portion is twisted so that the angle of the lower end with respect to the upper end thereof is 90 °.

Further, the upper stirring blade includes a columnar fixing member extending in the radial direction of the stirring shaft to fix the blade plate to the stirring shaft, and the blade plate is on the upper side and the lower side of the twisted portion. It is preferable to have a flat plate-shaped connecting portion provided in each of the above and to which one end of the fixing member is connected.

Further, the upper stirring blade includes a columnar fixing member extending in the radial direction of the stirring shaft to fix the blade plate to the stirring shaft, and the fixing member has a lower front surface in the rotation direction of the stirring shaft. It is preferable that it is inclined so as to face.

According to the stirring device according to the present invention, it is possible to generate a flow in an appropriate direction for the fluid at each portion in the length direction of the upper stirring blade. As a result, the circulating flow generated in the fluid in the stirring tank can be promoted, and the stirring time of the fluid can be shortened.

It is a figure which shows the schematic structure of the stirring apparatus which concerns on one Embodiment of this invention. It is a front view which shows the upper stirring blade which concerns on one Embodiment of this invention. It is a top view which shows the upper stirring blade which concerns on one Embodiment of this invention. It is a figure explaining the flow of the fluid by the stirring apparatus which concerns on one Embodiment of this invention. It is a figure explaining the flow of the fluid by the stirring apparatus which concerns on one Embodiment of this invention. It is a front view which shows the modification of the upper stirring blade which concerns on one Embodiment of this invention. It is sectional drawing which shows the modification of the fixing member which concerns on one Embodiment of this invention.

The stirring device according to the present invention is used for blending (stirring) various fluids (liquids and the like), and in particular, a viscous fluid having a relatively high viscosity, for example, a viscosity of about several thousand (mPa · s). It is suitable for use in dispersion mixing and dissolution mixing of viscous products such as ice mix. Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a stirring device according to an embodiment of the present invention, FIG. 2 is a front view showing an upper stirring blade, and FIG. 3 is a top view showing an upper stirring blade. .. Further, FIG. 4 is a diagram for explaining the flow of the fluid in the stirring tank by the lower stirring blade, and FIG. 5 is a diagram for explaining the flow of the fluid in the stirring tank by the upper stirring blade. Further, FIG. 6 is a front view showing a modified example of the upper stirring blade. FIG. 7 is a diagram showing a modified example of the fixing member, and is a sectional view taken along the line AA ′ of FIG.

As shown in FIGS. 1 to 3, the stirring device 1 includes a stirring shaft 10 rotatably suspended in the central portion of the stirring tank 100 and a lower stirring blade 20 attached to the lower end portion of the stirring shaft 10. The upper stirring blade 30 attached above the lower stirring blade 20 of the stirring shaft 10 is provided.

The stirring tank 100 is a container in which various raw materials (fluids, powders and granules, etc.) are stored, and the stirring device 1 stirs (mixes, etc.) the raw materials supplied to the stirring tank 100 in the stirring tank 100. ..

The stirring tank 100 has a substantially cylindrical shape, and its bottom surface 101 is formed in a curved surface shape. The upper surface 102 of the stirring tank 100 is provided with a sealable supply port 103, and various raw materials are supplied into the stirring tank 100 from the supply port 103. The structure of the stirring tank 100 is not particularly limited, and various existing structures can be adopted.

The stirring shaft 10 constituting the stirring device 1 is arranged in the central portion of the stirring tank 100, and one end portion (lower end portion) thereof is located near the bottom surface 101 of the stirring tank 100. The other end side of the stirring shaft 10 extends to the outside of the upper surface 102 of the stirring tank 100 and is connected to, for example, a driving means 50 such as a motor. The stirring shaft 10 is driven by the driving means 50 and is configured to rotate at a predetermined rotation speed.

The lower stirring blade 20 is attached near the lower end of the stirring shaft 10. The lower stirring blade 20 is a so-called flat paddle blade, and includes a plurality of flat plate-shaped blade plates (blades) 21 (in this embodiment, two blades). These blade plates 21 are arranged around the stirring shaft 10 at equal intervals (in this embodiment, at intervals of 180 °) and fixed to the stirring shaft 10.

The shape of the blade plate 21 is not particularly limited, but the lower edge portion of each blade plate 21 is formed along the shape of the bottom surface 101 of the stirring tank 100 having a curved surface shape. That is, the lower edge portion of each blade plate 21 is formed in a curved shape along the bottom surface of the stirring tank 100, and is arranged close to each other so as not to come into contact with the bottom surface 101 of the stirring tank 100.

The blade plate 21 included in the lower stirring blade 20 is not limited to the above configuration. Although two blade plates 21 are provided around the stirring shaft 10, four blade plates 21 may be provided around the stirring shaft 10 at 90 ° intervals. Further, although the blade plate 21 is arranged in the vertical direction along the axial direction of the stirring shaft 10, it may be arranged so as to be slightly inclined with respect to the axial direction of the stirring shaft 10.

The size of the lower stirring blade 20 is not particularly limited, but for example, the diameter D1 of the lower stirring blade 20 including the two blade plates 21 is about ½ of the diameter (inner diameter D2) of the stirring tank 100. Is preferable.

The upper stirring blade 30 includes a plurality of long plate-shaped blade plates (blades) 31 extending in the vertical direction (two blades in this embodiment), and is fixed for fixing each blade plate 31 to the stirring shaft 10. It includes an upper fixing member 32 and a lower fixing member 33, which are members.

The blade plates 31 are arranged around the stirring shaft 10 at equal intervals (in this embodiment, at intervals of 180 °) and fixed to the stirring shaft 10. The arrangement of the blade plates 31 in the circumferential direction of the stirring shaft 10 is not particularly limited, but each blade plate 31 is arranged directly above the blade plate 21 of the lower stirring blade 20 (above the vertical direction). That is, the upper stirring blade 30 extends from the stirring shaft 10 toward the outside of the stirring tank 100 in the same direction as the lower stirring blade 20.

Each blade plate 31 is arranged apart from the stirring shaft 10 by a predetermined length, its upper end is fixed to the stirring shaft 10 via the upper fixing member 32, and the lower end thereof is stirred via the lower fixing member 33. It is fixed to the shaft 10. That is, the blade plate 31 is fixed to the stirring shaft 10 in a state where a space having a predetermined size is secured between the blade plate 31 and the stirring shaft 10.

Further, the blade plate 31 is arranged so as to be inclined so that the upper end side thereof approaches the stirring shaft 10. More specifically, the blade plate 31 is arranged so that the inclination angle θ1 with respect to the stirring shaft 10 is a predetermined angle. The inclination angle θ1 of the blade plate 31 may be appropriately determined, but is preferably in the range of, for example, 10 to 15 °.

Then, these blade plates 31 are fixed to the stirring shaft 10 in a twisted state in the length direction thereof. More specifically, each blade plate 31 is twisted so that its lower end side rotates in the direction opposite to the rotation direction of the stirring shaft 10 with respect to the upper end side, in other words, its upper end side with respect to the lower end side. It is fixed to the stirring shaft 10 in a twisted state so as to rotate in the rotation direction of the stirring shaft 10.

In the present embodiment, each blade plate 31 has a twisted portion 34 and flat plate-shaped connecting portions 35 and 36 provided on the upper side and the lower side of the twisted portion 34, respectively, and is twisted. The lower end side of the beam 34 is twisted so as to rotate in the direction opposite to the rotation direction of the stirring shaft 10 with respect to the upper end side.

The connecting portion 35 extends in a flat plate shape on the upper side of the twisted portion 34, and the upper fixing member 32 is connected to the connecting portion 35. The connecting portion 36 extends in a flat plate shape below the twisted portion 34, and the lower fixing member 33 is connected to the connecting portion 36.

The upper fixing member 32 includes a columnar portion 37 extending in the radial direction of the stirring shaft 10, and the tip end portion of the columnar portion 37 is connected to the connecting portion 35 of the blade plate 31. The lower fixing member 33 includes a columnar portion 38 extending in the radial direction of the stirring shaft 10, and the vicinity of the tip end portion of the columnar portion 38 is connected to the connecting portion 36 of the blade plate 31. The shapes of the columnar portions 37 and 38 are not particularly limited, and may be, for example, a cylindrical shape or a prismatic shape.

The blade plate 31 fixed to the stirring shaft 10 in this way is twisted so that the lower end side of the twisted portion 34 rotates in the direction opposite to the rotation direction of the stirring shaft 10 with respect to the upper end side as described above. It has been tampered with.

For example, as shown in FIG. 3, when the rotation direction of the stirring shaft 10 is clockwise in the figure, the twisted portion 34 is twisted so that the lower end side thereof is counterclockwise in the figure with respect to the upper end side. It is fixed in the state of being fixed. The twisting amount (rotation amount) of the twisted portion 34 may be appropriately set, but in the present embodiment, the angle θ2 of the lower end with respect to the upper end thereof is set to about 90 °.

Further, each blade plate 31 is arranged so that the direction (plane direction) of the upper end of the twisted portion 34 is orthogonal to the radial direction (X direction in FIG. 3) of the stirring shaft 10. That is, the blade plate 31 is arranged so that the front surface (the surface on the front side when rotating) 31a faces the stirring shaft 10 side at the upper end of the twisted portion 34. The direction (plane direction) of the upper end of the twisted portion 34 does not necessarily have to be orthogonal to the radial direction of the stirring shaft 10. For example, the blade plate 31 may be arranged so that the direction of the upper end of the twisted portion 34 intersects the radial direction of the stirring shaft 10.

In the present embodiment, since the angle θ2 formed by the upper end and the lower end of the twisted portion 34 is 90 °, the direction of the lower end of the twisted portion 34 substantially coincides with the radial direction of the stirring shaft 10. It will be. In other words, the front surface 31a of the blade plate 31 faces the direction orthogonal to the radial direction of the stirring shaft 10, that is, the rotation direction of the stirring shaft 10 at the lower end of the twisted portion 34.

When the upper stirring blade 30 provided with such a blade plate 31 is rotated together with the stirring shaft 10, the fluid around the stirring shaft 10 is moved to the central portion side (stirring shaft 10 side) of the stirring tank 100 at the upper part of the blade plate 31. A flow toward the outside of the stirring tank 100 is generated in the fluid around the stirring shaft 10 at the lower part of the blade plate 31.

That is, the twisted portion 34 is provided with a first inclined portion that inclines so as to cause a flow toward the stirring shaft 10 side in the fluid around the stirring shaft 10, and a fluid provided below the first inclined portion. It is configured to include a second inclined portion in which the direction of the flow generated in the first inclined portion is inclined so as to be outside the stirring tank 100 with respect to the direction of the flow of the fluid generated in the first inclined portion.

As a result, a downward flow (downward flow) can be generated in the fluid around the stirring shaft 10, or the already generated downward flow can be strengthened. Further, it is possible to generate an ascending flow (upward flow) in the fluid on the outer peripheral portion of the stirring tank 100, or to strengthen the already generated ascending flow. As a result, the vertical circulation flow generated in the stirring tank 100 can be promoted.

Further, in the present embodiment, since the blade plate 31 is tilted at a predetermined angle with respect to the stirring shaft 10, the direction of the flow generated in the fluid around the stirring shaft 10 is slightly downward on the upper side of the blade plate 31. On the lower side of the blade plate 31, the direction of the flow generated in the flow around the stirring shaft 10 is slightly upward. As a result, a downward flow around the stirring shaft 10 and an upward flow at the outer peripheral portion of the stirring tank 100 are more likely to be generated or strengthened. Therefore, the circulating flow in the stirring tank 100 can be further promoted.

Hereinafter, the flow of the fluid generated in the stirring tank 100 when the highly viscous fluid is stirred by the stirring device 1 according to the present embodiment will be described in more detail.

In the stirring device 1 according to the present embodiment, a flow is generated in the fluid in the stirring tank 100 by each of the lower stirring blade 20 and the upper stirring blade 30 rotating together with the stirring shaft 10, and these flows are combined to be in the stirring tank 100. A vertical circulation flow is formed throughout.

First, the flow of the fluid generated by the lower stirring blade 20 will be described. As shown in FIG. 4, the lower stirring blade 20 which is a flat paddle blade rotates together with the stirring shaft 10, so that the fluid flows from the central portion side to the outer peripheral portion side of the stirring tank 100 at the bottom of the stirring tank 100 ( Discharge flow) f1 is generated. The discharge flow f1 is an ascending flow f2 that rises along the wall surface of the stirring tank 100 at the outer peripheral portion of the stirring tank 100. When the ascending flow f2 reaches the vicinity of the liquid level of the fluid, it becomes a flow toward the inside of the stirring tank 100 (the stirring shaft 10 side), and then a downward flow toward the bottom surface 101 side of the stirring tank 100 near the stirring shaft 10. It becomes f3.

Here, although it depends on the amount of the fluid to be agitated, when the viscosity of the fluid is relatively low, the lower stirring blade 20 generates a discharge flow f1, an ascending flow f2, and a descending flow f3, and the stirring tank 100 contains the discharge flow f1, the ascending flow f2, and the descending flow f3. A circulating flow in the vertical direction is well formed.

However, when the fluid to be agitated is a viscous fluid, it is difficult for the ascending flow f2 along the wall surface of the stirring tank 100 generated by the lower stirring blade 20 to reach the vicinity of the liquid surface, and accordingly, it becomes a fluid around the stirring shaft 10. However, the downward flow f3 is not sufficiently generated. Therefore, the vertical circulation flow is not well formed in the stirring tank 100, and the fluid may not be sufficiently stirred, or the stirring may take a long time.

However, since the stirring device 1 according to the present invention includes the upper stirring blade 30 together with the lower stirring blade 20, even a highly viscous viscous fluid can be satisfactorily stirred in a relatively short time.

As shown in FIG. 5, by rotating the upper stirring blade 30 together with the stirring shaft 10, the stirring shaft is around the stirring shaft 10 in the upper part of the stirring tank 100, that is, in the space between the stirring shaft 10 and the blade plate 31. A downward flow f4 toward the bottom surface side of the stirring tank 100 is generated while spirally swirling around the 10. The number of times the descending flow f4 swirls around the stirring shaft 10 tends to increase as the viscosity of the fluid increases.

The upper stirring blade 30 has a blade plate 31 including a twisted portion 34 as described above, and the direction of the front surface 31a of the blade plate 31 rotates around the stirring shaft 10 toward the lower side of the blade plate 31. It is gradually changing to face the flow of fluid.

Therefore, in the upper part of the blade plate 31 (particularly, the upper part of the twisted portion 34), the fluid collides with the front surface 31a of the blade plate 31 of the upper stirring blade 30, so that the fluid faces inward (stirring shaft 10). A flow f5 (toward the side) will occur. As a result, a spiral downward flow f4 is likely to be generated in the fluid around the stirring shaft 10.

On the other hand, in the lower part of the blade plate 31 (particularly, the lower part of the twisted portion 34), the fluid collides with the front surface 31a of the blade plate 31 of the upper stirring blade 30, so that the fluid is brought to the outside of the stirring tank 100. An oncoming flow f6 will occur. This also facilitates the generation of a spiral downward flow f4 in the fluid around the stirring shaft 10.

Further, it can be said that the fluid flow around the stirring shaft 10 is dense on the upper side of the blade plate 31 and sparse on the lower side of the blade plate 31. That is, in the first region S1 which is the upper side of the blade plate 31 between the stirring shaft 10 and the blade plate 31, the fluid is sent to the stirring shaft 10 side by the blade plate 31, so that the flow tends to be dense. On the other hand, in the second region S2 below the first region S1, the fluid is sent to the outer peripheral portion side of the stirring tank 100 by the blade plate 31, so that the flow around the stirring shaft 10 tends to be sparse.

As described above, the fluid flow becomes dense in the first region S1 and the fluid flow becomes sparse in the second region S2, so that the fluid flows from the first region S1 to the second region S2 around the stirring shaft 10. It becomes easy to flow. Further, there is also an effect that the fluid in the first region S1 is drawn into the second region S2 as the fluid is sent out of the stirring tank 100 by the blade plate 31 in the second region S2. As a result, the spiral downward flow f4 is likely to be generated in the fluid around the stirring shaft 10, or the spiral downward flow f4 is likely to be strengthened.

Further, the fluid flow f6 generated in the lower part of the blade plate 31 toward the outer peripheral portion of the stirring tank 100 becomes an ascending flow f7 that rises along the wall surface of the stirring tank 100 in the outer peripheral portion of the stirring tank 100.

Then, by combining the flow of the fluid generated by the lower stirring blade 20 and the flow of the fluid generated by the upper stirring blade 30 in this way, a circulation flow in the vertical direction is satisfactorily formed in the entire stirring tank 100.

For example, in the outer peripheral portion of the stirring tank 100, the rising flow f2 generated by the lower stirring blade 20 and the rising flow f7 generated by the upper stirring blade 30 are combined to strengthen the rising flow in the outer peripheral portion of the stirring tank 100. Therefore, even when the viscous fluid is agitated, the ascending flow in the outer peripheral portion of the stirring tank 100 reaches the vicinity of the liquid surface, and the fluid in the stirring tank 100 can be satisfactorily formed with a circulating flow in the vertical direction. can.

Further, in the present embodiment, since the blade plate 31 is tilted with respect to the stirring shaft 10 at a predetermined angle θ1 (see FIG. 2), the fluid flow f5 in the upper part of the twisted portion 34 is the stirring tank 100. The flow is on the central side (stirring shaft 10 side) and slightly downward. On the other hand, the fluid flow f6 in the lower part of the twisted portion 34 is a flow outside the stirring tank 100 and slightly upward. As a result, the spiral downward flow generated in the fluid around the stirring shaft 10 and the upward flow generated in the outer peripheral portion of the stirring tank 100 are further strengthened.

Further, the fluid around the stirring shaft 10 is sent toward the outside of the stirring tank 100 at the lower part of the blade plate 31 as described above, while the spiral downward flow also causes the fluid to correspond to the lower stirring blade 20. It flows in. This also has the effect of strengthening the discharge flow generated by the rotation of the lower stirring blade 20.

As described above, according to the stirring device 1 according to the present embodiment, an appropriate flow can be generated in the fluid in the stirring tank 100. Therefore, even when the viscous fluid is agitated, the circulating flow in the vertical direction can be satisfactorily promoted in the agitating tank 100, and the agitation (mixing) time of the fluid can be shortened.

In particular, since the blade plate 31 has the twisted portion 34, that is, the blade plate 31 is in a twisted state, the fluid flow around the stirring shaft 10 is in the vertical direction of the blade plate 31. It does not change extremely in, but gradually (stepwise) changes toward the lower side of the blade plate 31. Therefore, the flow of the fluid around the stirring shaft 10 becomes smooth, and the vertical circulation flow in the stirring tank 100 can be promoted more appropriately. As a result, it becomes possible to further shorten the stirring (mixing) time of the fluid.

As described above, the stirring device of the embodiment provided with the lower stirring blade and the upper stirring blade, and the blade plate of the upper stirring blade has a twisted portion, and the inverted V shape as in Patent Document 1 mentioned in the background technology. The mixing time (stirring time) of the stirrer of the comparative example including the upper stirrer blade of the mold and the lower stirrer blade of the flat paddle was measured until the mixture was mixed with the solution which is a viscous fluid. It has been obtained that the mixing time (stirring time) of the stirring device is significantly shortened to 1/2 or less as compared with the stirring device of the comparative example.

Although one embodiment of the present invention has been described above, the configuration of the present invention is not limited to the above-described embodiment.

For example, in the above-described embodiment, the blade plate 31 of the upper stirring blade 30 is arranged so as to be inclined so that the upper end side thereof approaches the stirring shaft 10, but the blade plate 31 does not necessarily have to be inclined. .. As shown in FIG. 6, each blade plate 31 may be arranged in a substantially vertical direction in parallel with the stirring shaft 10 at a distance from the stirring shaft 10 by a predetermined length, for example.

Even with such a configuration, depending on various conditions at the time of stirring, even when the viscous fluid is agitated, the circulating flow can be promoted better than before, and the agitation (mixing) time of the fluid can be shortened. can.

Further, in the above-described embodiment, the upper stirring blade 30 extends in the same direction as the lower stirring blade 20, but in a direction intersecting the lower stirring blade 20, for example, in a direction orthogonal to the lower stirring blade 20. It may be postponed.

Further, in the above-described embodiment, the blade plate 31 of the upper stirring blade 30 is fixed to the stirring shaft 10 by the upper fixing member 32 and the lower fixing member 33. Not limited to the configuration. For example, the central portion of the blade plate 31 in the length direction (vertical direction) may be fixed to the stirring shaft 10 by one fixing member.

Further, in the above-described embodiment, the blade plate 31 of the upper stirring blade 30 includes a twisting portion 34 and connecting portions 35 and 36 provided above and below the twisting portion 34, but the upper fixing member 32 and the lower fixing member 33 are provided. The flat plate-shaped connecting portions 35 and 36 may not be provided as long as they can be appropriately connected to the above. That is, the blade plate 31 may be fixed to the stirring shaft 10 in a twisted state over its length direction. With these configurations, the flow of fluid around the stirring shaft 10 tends to be smoother.

Further, the shapes of the upper fixing member 32 and the lower fixing member 33 to which the blade plate 31 of the upper stirring blade 30 is fixed, for example, the shapes of the columnar portions 37 and 38 are not limited to the above-described embodiment. For example, as shown in FIG. 7, the columnar portion 37 of the upper fixing member 32 may be formed so that the front surface 37a in the rotation direction of the stirring shaft 10 is inclined downward. In this example, the front surface 37a of the columnar portion 37 is formed on a curved surface, but may be formed on a flat surface.

As a result, when the stirring shaft 10 is rotated, a downward flow is generated in the fluid around the stirring shaft 10 also by the front surface 37a of the columnar portion 37. Therefore, the downward flow generated in the fluid around the stirring shaft 10 is further strengthened, and the vertical circulation flow in the stirring tank 100 is formed more satisfactorily. Of course, not only the columnar portion 37 of the upper fixing member 32 but also the columnar portion 38 of the lower fixing member 33 may have the same shape.

Further, in the above-described embodiment, the present invention has been described assuming that the stirring device is configured as a separate body from the stirring tank, but of course, the stirring device may be configured to include the stirring tank.

1 ... Stirring device, 10 ... Stirring shaft, 20 ... Lower stirring blade, 21 ... Blade plate (blade), 30 ... Upper stage stirring blade, 31 ... Blade plate (blade), 31a ... Front surface, 32 ... Upper fixing member, 33 ... Lower fixing member, 34 ... twisted portion, 35, 36 ... connecting portion, 37, 38 ... columnar portion, 50 ... driving means, 100 ... stirring tank, 101 ... bottom surface, 102 ... top surface, 103 ... supply port

In the first aspect of the present invention to solve the above problems, the stirring shaft rotatably suspended in the stirring tank, the lower stirring blade attached to the lower end of the stirring shaft, and the stirring shaft are separated from each other. The blade plate of the upper stage stirring blade is provided with an upper stage stirring blade which has a blade plate arranged along the stirring shaft and is attached above the lower stage stirring blade of the stirring shaft. In the upper part of the stirring shaft, a flow toward the center of the stirring tank is generated in the fluid around the stirring shaft, and in the lower part of the blade plate, a flow toward the outside of the stirring tank is generated in the fluid around the stirring shaft. The stirring device is characterized in that the lower end side thereof has a twisted portion twisted so as to rotate in a direction opposite to the rotation direction of the stirring shaft with respect to the upper end side.

Further, it is preferable that the blade plate of the upper stirring blade is arranged so that the surface on the front side when the stirring shaft rotates faces the stirring shaft side at the upper end of the twisted portion .

Further, the upper stirring blade includes a columnar fixing member extending in the radial direction of the stirring shaft to fix the blade plate to the stirring shaft, and the fixing member is on the front side when the stirring shaft rotates. It is preferable that the surface is formed so as to incline downward .

Claims (8)

A stirring shaft rotatably installed in the stirring tank,
The lower stirring blade attached to the lower end of the stirring shaft and
It has a blade plate arranged along the stirring shaft at a distance from the stirring shaft, and includes an upper stirring blade mounted above the lower stirring blade of the stirring shaft.
The blade plate of the upper stirring blade is a stirring device having a twisted portion twisted so that its lower end side rotates in a direction opposite to the rotation direction of the stirring shaft with respect to the upper end side. The stirring device according to claim 1.
A stirring device characterized in that the blade plate of the upper stirring blade is arranged so as to be inclined so that the upper end side thereof approaches the stirring axis. The stirring device according to claim 2.
A stirring device characterized in that the blade plate of the upper stirring blade is inclined in a range of 10 to 15 ° with respect to the stirring axis. The stirring device according to any one of claims 1 to 3.
A stirring device, wherein each blade plate of the upper stirring blade is arranged directly above the lower stirring blade. The stirring device according to any one of claims 1 to 4.
The blade plate of the upper stirring blade is a stirring device characterized in that the surface direction at the upper end of the twisted portion is arranged so as to be orthogonal to the rotation direction of the stirring shaft. The stirring device according to any one of claims 1 to 5.
The twisted portion is a stirring device characterized in that the twisted portion is twisted so that the angle of the lower end with respect to the upper end thereof is 90 °. The stirring device according to any one of claims 1 to 6.
The upper stirring blade includes a columnar fixing member extending in the radial direction of the stirring shaft to fix the blade plate to the stirring shaft.
The blade plate is a stirring device provided on each of the upper side and the lower side of the twisted portion, and has a flat plate-shaped connecting portion to which one end of the fixing member is connected. The stirring device according to any one of claims 1 to 7.
The upper stirring blade includes a columnar fixing member extending in the radial direction of the stirring shaft to fix the blade plate to the stirring shaft.
The fixing member is a stirring device characterized in that the front surface in the rotation direction of the stirring shaft is inclined so as to face downward.

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