JPWO2017212935A1 - Stirring blade and stirring device - Google Patents

Abstract

A stirring blade used in a stirring device and rotated around a predetermined axis is provided. The stirring blade includes a base portion and a plurality of blade portions. The plurality of blade portions are provided on the same side of the base portion and arranged around the axis. Each of the plurality of blade portions has an inner end in a radial direction perpendicular to the axis, and a forward curved portion connected to the inner end and protruding forward in the rotational direction. The stirring blade having such a configuration appropriately stirs the material to be stirred, which contributes to improvement in the degree of dispersion and mixing of the target material.

Description

  The present disclosure relates to a stirring blade and a stirring device.

  Conventionally, a stirring device for mixing a plurality of substances with each other is known. For example, Patent Document 1 below discloses an example of a stirring device using a stirring blade. This conventional stirring blade is attached to the tip of a shaft that is rotationally driven, and a mixture to be stirred (“target material”) is contained in a predetermined container. The target material is agitated by rotating the agitating blade in the container.

  In general, in a conventional stirring apparatus, the target material is sufficiently stirred in the vicinity of the stirring means (such as the above-described stirring blade), and different substances are well mixed (highly dispersed). On the other hand, at a place away from the stirring means, the target material is not sufficiently stirred, and the degree of dispersion becomes low. Thus, in the conventional stirring apparatus, the degree of dispersion varies depending on the location, and the entire target material tends to be qualitatively non-uniform (that is, the degree of mixing is low).

Japanese Patent Laid-Open No. 10-180073

  The present disclosure has been conceived under the circumstances described above. Therefore, an object of the present disclosure is to provide a stirring blade and a stirring device capable of improving both the degree of dispersion and the degree of mixing of the target material as compared with the related art.

  According to a first aspect of the present disclosure, a stirring blade that rotates about an axis is provided. The stirring blade includes a base portion and a plurality of first blade portions provided on the first side of the base portion and arranged around the axis. Each of the plurality of first blade portions includes an inner end in a radial direction perpendicular to the axis, and a forward curved portion connected to the inner end and protruding forward in the rotational direction.

  Preferably, each said 1st blade | wing part has a back curved part which is connected to the said radial direction outward with respect to the said front curved part, and is convex in the said rotation direction.

  Preferably, each said 1st blade | wing part inclines so that it may be located in the said rotation direction front, so that it separates from the said base part in the direction parallel to the said axial center.

  Preferably, the inclination angle of each of the first blade portions with respect to a direction parallel to the axis is greater toward the inner side in the radial direction.

  Preferably, the stirring blade further includes a plurality of second blade portions. In addition, the base portion has a second side opposite to the first side, and the plurality of second blade portions are provided on the second side and arranged around the axis.

  Preferably, the plurality of first blade portions are different from the plurality of second blade portions in positions in the rotation direction.

  Preferably, the base has a first inclined surface and a second inclined surface that are tapered in opposite directions. The plurality of first blade portions are provided on the first inclined surface, and the plurality of second blade portions are provided on the second inclined surface.

  The stirring device provided by the second aspect of the present disclosure includes a stirring blade according to the first side, a container that accommodates a stirring target, a rotating shaft that is inserted into the container and to which the stirring blade is attached, Is provided.

  Other features and advantages of the present disclosure will become more apparent from the detailed description given below with reference to the accompanying drawings.

It is a perspective view which shows the stirring blade based on 1st Embodiment of this indication. It is a front view which shows the stirring blade based on 1st Embodiment of this indication. It is a top view which shows the stirring blade based on 1st Embodiment of this indication. It is sectional drawing which shows the stirring apparatus using the stirring blade based on 1st Embodiment of this indication. It is a perspective view which shows the stirring blade based on 2nd Embodiment of this indication. It is a top view which shows the stirring blade based on 2nd Embodiment of this indication. It is a figure which shows the stirring state by the stirring blade of 1st Embodiment. It is a figure which shows the stirring state by the stirring blade of 2nd Embodiment. It is a perspective view which shows the stirring blade of a comparative example. It is a figure which shows the stirring state by the stirring blade of a comparative example. It is a perspective view which shows the stirring blade based on 3rd Embodiment of this indication. It is a front view which shows the stirring blade based on 3rd Embodiment of this indication. It is sectional drawing which shows an example of the stirring apparatus using the stirring blade based on 3rd Embodiment of this indication. It is a perspective view which shows the stirring blade based on 4th Embodiment of this indication. It is a perspective view which shows the stirring blade based on 5th Embodiment of this indication. It is a figure which shows the stirring state by the stirring blade of 3rd Embodiment. It is a figure which shows the stirring state by the stirring blade of 4th Embodiment. It is a figure which shows the stirring state by the stirring blade of 5th Embodiment. It is a figure which shows the stirring state by the stirring blade of a comparative example. It is a figure which shows the flow tracking analysis result of the marker stirred by the stirring blade of 3rd Embodiment. It is a figure which shows the flow tracking analysis result of the marker stirred by the stirring blade of 4th Embodiment. It is a figure which shows the flow tracking analysis result of the marker stirred by the stirring blade of 5th Embodiment. It is a figure which shows the flow tracking analysis result of the marker stirred by the stirring blade of the comparative example. It is sectional drawing which shows the other example of the stirring apparatus using the stirring blade of 3rd Embodiment.

  Hereinafter, preferred embodiments of the present disclosure will be specifically described with reference to the drawings.

  In the present disclosure, “stirring” is not particularly limited, and may mean “dispersion” and “mixing”. Dispersion means that another substance (for example, a powder or another kind of liquid) is microscopically dispersed in a substance (for example, a liquid) that is chemically in one phase. Moreover, mixing means making dispersion degree uniform over the whole object material. For example, it is assumed that the target material is composed of liquid A and powder B. In this case, the “stirring” of the target material means that the powder B (at least a part thereof) is dispersed in the liquid A (at least a part thereof) (“dispersion”), and the scattered state of the powder B is the target material. Can be the same (or substantially the same) at any point in the target material to create a predetermined flow ("mixing").

  1 to 3 show a stirring blade according to the first embodiment of the present disclosure. The illustrated stirring blade A <b> 1 includes a base 1 and a blade group 2.

  FIG. 1 is a perspective view showing the stirring blade A1. FIG. 2 is a front view showing the stirring blade A1. FIG. 3 is a plan view showing the stirring blade A1. 1 and 3, the direction (circumferential direction) in which the stirring blade A1 rotates is indicated by θ. In FIG. 2, the direction in which the stirring blade A1 rotates is indicated by an arrow attached below the stirring blade A1. In these drawings, the direction (axial direction) parallel to the rotation axis of the stirring blade A1 is indicated by z, and the direction perpendicular to the axial direction z (radial direction) is indicated by r.

  The stirring blade A1 is attached to, for example, the stirring device B1 shown in FIG. The stirrer B1 includes a container 81, a rotary shaft 82, a drive unit 83, and a shaft seal 85. The container 81 accommodates the target material T to be stirred. The rotating shaft 82 extends vertically through the bottom of the container 81, and a stirring blade A1 is attached to the upper end thereof. The shaft seal 85 is provided between the bottom of the container 81 and the rotating shaft 82 and allows the rotating shaft 82 to rotate, while preventing the target material T from leaking out of the container 81. The drive unit 83 includes, for example, an electric motor in order to rotate the rotation shaft 82 around a predetermined axis parallel to the axial direction z. Other components of the stirring device B1 are not particularly limited, and a housing that supports the container 81 and the drive unit 83, a control unit that controls the drive of the drive unit 83, and the like may be appropriately provided.

  The stirring blade A1 is not particularly limited, and is formed of a material suitable for stirring the target material T, such as metal or resin. Examples of the metal forming the stirring blade A1 include stainless steel. The stirring blade A1 may be one in which the base 1 and the blade group 2 are integrally formed, or may be configured by combining a plurality of individually formed parts. As means for attaching the stirring blade A1 to the rotary shaft 82, a well-known engagement mechanism, fastening mechanism, or the like can be adopted. Alternatively, a part of the stirring blade A1 may be fixed (for example, bonded) to the rotating shaft 82 in advance, and the remaining part of the stirring blade A1 may be detachably attached to the part. The magnitude | size of stirring blade A1 is not specifically limited, According to the size of the container 81, the viscosity of the target material T, etc., it selects suitably. In one example, the diameter of the stirring blade A1 is about 40 mm.

  The base 1 supports the blade group 2 and is fixed to the rotating shaft 82. The shape and size of the base 1 are not particularly limited. The illustrated base 1 has a circular shape in a plan view (viewed in the axial direction z). The base 1 has an outer peripheral end 10 and an inclined surface 11. In the present embodiment, the outer peripheral end 10 is located at the lower end of the base 1 and is circular in plan view. The inclined surface 11 is provided above the outer peripheral end 10. The inclined surface 11 has a configuration in which the size in the radial direction r decreases as it goes upward in the axial direction z. In other words, the inclined surface 11 is tapered upward. In the illustrated example, the base 1 as a whole is a truncated cone (a truncated cone), and the inclined surface 11 is constituted by a side surface of the truncated cone.

  The blade group 2 includes a plurality of blade portions 20. These blade portions 20 are provided on the same surface side of the base portion 1 and are spaced apart from each other in the rotation direction θ. In the present embodiment, the plurality of blade portions 20 are provided on the inclined surface 11. As shown in FIG. 2, the plurality of blade portions 20 are arranged within a predetermined range in the axial direction z.

  The number of blade portions constituting the blade group 2 is not particularly limited. In the present embodiment, the blade group 2 includes four blade portions 40. These four blade portions 20 are arranged at an equal pitch in a plan view and are separated from each other by 90 degrees in the rotation direction θ.

  Each blade 20 has an inner end 21, an outer end 22, a base end 23, a distal end 24, a front surface 25, a rear surface 26, a front curved portion 27 and a rear curved portion 28. The inner end 21 is a linear or curved edge that is located at the innermost position in the radial direction r in the blade portion 20 and has a predetermined length. In the present embodiment, the inner ends 21 of the plurality of blade portions 20 are separated from each other in the rotation direction θ. The outer end 22 is the outermost edge of the blade portion 20 in the radial direction r, and is a linear or curved edge having a predetermined length. As shown in FIG. 3, the outer end 22 coincides with the outer peripheral end 10 of the base 1 in a plan view. That is, either the base 1 or the blade 20 is not configured to protrude outward in the radial direction r from the other. In another example, at least one blade portion 20 may be configured to protrude outward in the radial direction r from the base portion 1 or may be configured to be retracted inward in the radial direction r from the base portion 1. Good.

  The base end 23 is a part where the blade part 20 is connected to the base part 1. The distal end 24 is a linear or curved edge that is spaced apart from the proximal end 23 in the axial direction z and has a predetermined length.

  The front surface 25 of each blade 20 is a front surface in the rotational direction θ, and the rear surface 26 is a rear surface.

  The front bending portion 27 is a portion that is connected to the inner end 21 and is convex forward in the rotation direction θ in plan view. More specifically, the front bending portion 27 has a shape that is convex forward in the rotational direction θ with respect to a virtual straight line connecting both ends in the radial direction r of the front bending portion 27. The rear bending portion 28 is a portion that is connected to the outer side in the radial direction r with respect to the front bending portion 27 and is convex rearward in the rotation direction θ in plan view. More specifically, the rear bending portion 28 has a shape that protrudes rearward in the rotational direction θ with respect to a virtual straight line connecting both ends in the radial direction r of the rear bending portion 28. In FIG. 1 and FIG. 3, each range is shown with the dashed-dotted line with an arrow about the front bending part 27 and the back bending part 28. FIG. In the illustrated example, the tip 24 is provided in a portion of the blade portion 20 that substantially constitutes the front bending portion 27, and as shown in FIG. 3, is a shape that is convex forward in the rotational direction θ in plan view. It has become. Moreover, the base end 23 is provided in both the part which comprises the front curve part 27 and the back curve part 28, and as shown in FIG. 3, it has a S shape in planar view. In addition, the range in which the front bending portion 27 and the rear bending portion 28 are provided, the degree of bending of each, and the like are not particularly limited.

  Moreover, in this embodiment, each blade | wing part 20 is inclined so that it may be located ahead of the rotation direction (theta), so that it leaves | separates from the base 1 in the axial direction z. Further, in the present embodiment, the inclination angle of the blade portion 20 with respect to the axial direction z increases as it goes inward in the radial direction r. More specifically, as shown in FIG. 2, the angle α1 formed by the inner end 21 of the blade portion 20 with the axial direction z is larger than the angle α2 formed by the outer end 22 of the blade portion 20 with the axial direction z. It is. Accordingly, the angle formed by the front bending portion 27 with the axial direction z is larger than the angle formed by the rear bending portion 28 with the axial direction z.

  5 and 6 show a stirring blade according to the second embodiment of the present disclosure. In the illustrated stirring blade A2, the configuration of the blade portion 20 is different from that of the stirring blade A1 described above. FIG. 5 is a perspective view showing the stirring blade A2. FIG. 6 is a plan view of the stirring blade A2.

  In the present embodiment, each blade portion 20 has only one curved portion, that is, the front curved portion 27, and does not have the rear curved portion 28. As shown in FIG. 6, the entire blade portion 20 is configured by a front bending portion 27 in a plan view. The relative relationship between the plurality of blade portions 20 in the stirring blade A2 and the configuration of the base portion 1 are substantially the same as those of the stirring blade A1. As with the stirring blade A1, the stirring blade A2 is used by being attached to the stirring device B1 (FIG. 4).

  Next, the operation of the stirring blades A1 and A2 and the stirring device B1 will be described.

  7 and 8 show examples of analysis using numerical fluid dynamic simulation of stirring by the stirring blades A1 and A2. In these drawings, a plurality of arrows are attached corresponding to a plurality of points. Each arrow indicates the direction of the flow of the target material at that point (however, the rotation direction θ component is not considered). Further, the shading in the figure corresponds to the flow velocity of the target material and indicates the flow velocity distribution of the target material (however, the rotation direction θ component is not taken into consideration). A lighter color area has a relatively higher flow rate (maximum flow rate in the white area), and a darker color area has a relatively lower flow rate (black area has the lowest flow rate). The ratio of flow rates between adjacent regions is 2.15. The conditions for this analysis are as follows. The inner diameter of the container 81 is 126 mm. The target material T is a high-viscosity non-Newtonian fluid (carboxymethylcellulose sodium 1.7 wt%), and the liquid depth is 89.8 mm. In the center of the bottom of the container 81, a stirring blade A1 (FIG. 7) or A2 (FIG. 8) is arranged. The rotational speed (circumferential speed) of the stirring blades A1 and A2 is 10 m / s.

  When the stirring blades A <b> 1 and A <b> 2 rotate, the target material T generates a rotational flow along the rotational direction θ. As understood from the arrows in FIGS. 7 and 8, the target material T moves from above the stirring blades A1 and A2 (and near the liquid surface) to the stirring blades A1 and A2 along the axial direction z. After flowing downward, it flows from the lower ends of the stirring blades A1 and A2 (near the outer peripheral end 10) outward in the radial direction r along the bottom of the container 81. Furthermore, the target material T flows upward along the side wall of the container 81, that is, toward the liquid surface. As a result of such a flow, a large vortex is formed in the container 81. 7 and 8, the presence of two vortices that are symmetric with respect to the rotational axis of the stirring blades A1 and A2 is confirmed. Generation | occurrence | production of such a flow with a vortex mainly contributes to mixing of the object material T. FIG. Further, in the vicinity of the stirring blades A1 and A2, particularly in the vicinity of the outer peripheral end 10, the flow velocity is maximum (see the white area). As described above, the local increase in the flow velocity mainly contributes to the dispersion of the target material T. As described above, according to the stirring blades A1 and A2, after a part of the target material T is effectively dispersed in the vicinity of the stirring blades A1 and A2, the dispersed portion is moved to another position by the vortex flow described above. By doing, the effect that the target material T mixes appropriately over the whole is show | played.

  FIG. 9 shows the stirring blade X prepared for comparison with the stirring blades A1 and A2. The stirring blade X has a base 91, a first blade group 92a, and a second blade group 92b. The base 91 has a flat disk shape. The blade groups 92 a and 92 b are arranged along the outer periphery of the base 91. The first blade group 92 a includes a plurality of blade portions 920 that are bent upward with respect to the base portion 91. The second blade group 92 b includes a plurality of blade portions 920 that are bent downward with respect to the base portion 91. Each blade portion 920 is a substantially trapezoidal flat plate, and has an inner surface and an outer surface along the rotation direction θ. Such a stirring blade X is obtained, for example, by cutting and bending a metal plate.

  FIG. 10 shows an analysis example using a numerical fluid dynamics simulation performed on the stirring blade X (the outer diameter is the same as that of the stirring blades A1 and A2) under the same conditions as the fluid analysis examples shown in FIGS. Yes. As can be seen from FIG. 10, the flow velocity is maximum in the vicinity of the outer peripheral end of the stirring blade X. In addition, a flow accompanied by a vortex is generated on the left and right of the rotation axis of the stirring blade X. However, in the region near the side wall of the container 81 and the liquid surface of the target material T, the flow velocity is remarkably small. That is, when the stirring blade X is used, stirring is mainly performed only in the mushroom-like region including the stirring blade X, and substantial stirring is not performed in the other region. Thus, it can be seen that a larger flow rate is obtained in the wider range of the container 81 when the stirring blades A1 and A2 are used than when the stirring blade X is used. Therefore, according to the stirring blades A1 and A2, the entire target material T can be mixed more appropriately than the stirring blade X.

  As a factor that the mixing by the stirring blades A1 and A2 is appropriately performed, first, the contribution of the front curved portion 27 of the blade portion 20 can be cited. As shown in FIGS. 3 and 6, the forward bending portion 27 is convex forward in the rotational direction θ. According to the inventors' research, with such a configuration, it is possible to smoothly move the sucked target material T outward in the radial direction r while strongly sucking the target material T at the inner end 21. It turned out to be. In particular, in the illustrated example, the angle formed by the blade portion 20 at the inner end 21 and the rotational direction θ is relatively small (α1 in FIG. 2 is relatively large). It has been found that the material T is sucked more powerfully. Further, in the illustrated forward curved portion 27, the angle formed by the blade portion 20 and the rotation direction θ gradually increases toward the outer side in the radial direction r. It has been found that this configuration is advantageous for moving the sucked target material T more smoothly outward in the radial direction r. This strong suction and smooth movement is considered to be one factor that can mix the entire target material T more appropriately.

  Further, comparing the analysis example of the stirring blade A1 in FIG. 7 with the analysis example of the stirring blade A2 in FIG. 8, the thin tone region in FIG. 7 (the region where the flow velocity is fast) is larger than the thin tone region in FIG. It is getting wider. Unlike the stirring blade A2, the stirring blade A1 is provided with a backward curved portion 28 that is convex backward in the rotation direction θ. In other words, in the backward curved portion 28, the angle formed by the blade portion 20 and the rotation direction θ gradually increases toward the outer side in the radial direction r. According to the researches of the inventors, it has been found that the effect of discharging the sucked target material T from the stirring blade A1 to the outer side in the radial direction r can be obtained by the backward bending portion 28 having such a configuration. And it is thought that mixing of the whole object material T is accelerated | stimulated because reinforcement | strengthening of the suction by the front curved part 27 and reinforcement | strengthening of the discharge by the back curved part 28 act synergistically.

  Further, as described above, each blade 20 is inclined forward in the rotational direction θ. Thereby, it is possible to avoid the bubbles mixed in the target material T from staying at the boundary portion (corner portion) between the rear surface 26 and the inclined surface 11. If bubbles stay in the corner, mixing of the target material T by the stirring blades A1 and A2 is hindered. According to the stirring blades A <b> 1 and A <b> 2, no bubbles remain in the corners, which contributes to an improvement in the degree of mixing of the target material T.

  11 and 12 show a stirring blade A3 according to the third embodiment of the present disclosure. The stirring blade A3 includes a base 1 and a pair of blade groups (an upper blade group and a lower blade group) 2.

  FIG. 11 is a perspective view showing the stirring blade A3. FIG. 12 is a front view showing the stirring blade A3. The plan view of the stirring blade A3 is the same as the plan view (FIG. 3) of the stirring blade A1.

  The stirring blade A3 is attached to, for example, a stirring device B3 shown in FIG. The stirrer B3 includes a container 81, a rotary shaft 82, and a drive unit 83. The container 81 accommodates the target material T. A part of the rotating shaft 82 is inserted into the target material T of the container 81, and a stirring blade A3 is attached to the lower end thereof. The drive unit 83 rotates the rotary shaft 82 around the axial direction z, and includes, for example, an electric motor. Other components of the stirring device B3 are not particularly limited, and a casing that supports the container 81 and the drive unit 83, a control unit that controls the drive of the drive unit 83, and the like may be appropriately provided. .

  The base 1 of the stirring blade A3 supports the upper and lower blade groups 2. The base 1 has an outer peripheral end 10 and a pair of inclined surfaces (an upper inclined surface and a lower inclined surface) 11. The outer peripheral end 10 is located at the center in the axial direction z of the base 1 and is circular in plan view. The outer peripheral end 10 forms a boundary between the upper and lower blade groups 2. The upper and lower inclined surfaces 11 are provided so as to sandwich the outer peripheral end 10 in the axial direction z. The upper inclined surface 11 is tapered upward, and the lower inclined surface 11 is tapered downward. In the illustrated example, each inclined surface 11 is constituted by a side surface of a truncated cone (a truncated cone).

  Each blade group 2 includes a plurality of blade portions 20 arranged in the rotation direction θ. As shown in FIG. 12, the plurality of blade portions 20 of each blade group 2 are arranged in a predetermined range in the axial direction z. Further, the plurality of blade portions 20 of the upper blade group 2 are provided at positions shifted in the circumferential direction θ with respect to the plurality of blade portions 20 of the lower blade group 2. For this reason, in one example, the plurality of blade portions 20 of the upper blade group 2 are configured not to overlap with the plurality of blade portions 20 of the lower blade group 2 in the axial direction z. The structure of each blade part 20 is the same as the blade part 20 of the stirring blade A1 described above.

  In the illustrated example, the number of the plurality of blade portions 20 constituting each blade group 2 is four. In each blade group 2, the four blade portions 20 are arranged at an equal pitch in the circumferential direction θ, and are separated by 90 degrees in the circumferential direction θ.

  In the example shown in FIGS. 11 and 12, the blade portion 20 of the upper blade group 2 is disposed at a position shifted by 45 degrees (90 degrees / 2) in the rotation direction θ with respect to the blade portion 20 of the lower blade group 2. ing.

  FIG. 14 illustrates a stirring blade A4 according to the fourth embodiment of the present disclosure. The illustrated stirring blade A4 includes a pair of upper and lower blade groups 2 similar to the above-described stirring blade A3, and is attached to the stirring device B3 (FIG. 13), for example. The configuration of each blade portion 20 is the same as the blade portion 20 of the stirring blades A1 and A3 described above, and includes a front bending portion 27 and a rear bending portion. The plan view of the stirring blade A4 is the same as the plan view (FIG. 3) of the stirring blade A1. In the stirring blade A4, the number of the plurality of blade portions 20 constituting the upper and lower blade groups 2 is the same. Further, the plurality of blade portions 20 of the upper blade group 2 are provided at the same position as the plurality of blade portions 20 of the lower blade group 2 in the rotation direction θ.

  FIG. 15 illustrates a stirring blade A5 according to the fifth embodiment of the present disclosure. The illustrated stirring blade A5 is provided with a pair of upper and lower blade groups 2. The configuration of each blade portion 20 is the same as that of the stirring blade A2 described above, and includes the front curved portion 27, but does not include the rear curved portion 28. The plan view of the stirring blade A5 is the same as the plan view (FIG. 6) of the stirring blade A2. The plurality of blade portions 20 of the upper blade group 2 are arranged at positions shifted by 45 degrees (90 degrees / 2) with respect to the plurality of blade sections 20 of the lower blade group 2 in the rotation direction θ.

  Next, the operation of the stirring blades A3 to A5 and the stirring device B3 will be described.

  FIGS. 16-18 has shown the example of analysis using the numerical fluid dynamics simulation of stirring by stirring blade A3-A5. As in FIGS. 7 and 8, each arrow indicates the direction of the flow of the target material at that point (the rotation direction θ component is not taken into account), and the shading in the figure corresponds to the flow velocity of the target material. It shows the flow velocity distribution of the target material (excluding the rotation direction θ component). A lighter color area has a relatively higher flow rate (maximum flow rate in the white area), and a darker color area has a relatively lower flow rate (black area has the lowest flow rate). The ratio of flow rates between adjacent regions is 2.15. The conditions for this analysis are as follows. The inner diameter of the container 81 is 210 mm. The target material T is a high-viscosity non-Newtonian fluid (carboxymethylcellulose sodium 1.7 wt%), and the liquid depth is 158 mm. Agitation blades A3 (FIG. 16), A4 (FIG. 17), and A5 (FIG. 18) are arranged in the approximate center of the target material T. The rotation speed (circumferential speed) of the stirring blades A3 to A5 is 10 m / s.

  When the stirring blades A3 to A5 rotate in the direction θ, the target material T also generates a rotational flow in the same direction. Moreover, as understood from FIGS. 16 to 18, the flow of the target material T toward the stirring blades A3 to A5 is confirmed from above and below the stirring blades A3 to A5. Moreover, the flow which goes to radial direction r outward from the axial direction z center (near outer peripheral end 10 vicinity) of stirring blade A3-A5 is confirmed. Further, the flow is a flow toward the liquid surface of the target material T or the bottom surface of the container 81 along the side wall of the container 81. As a result of such a flow, two vortices are generated on both the left and right sides of the rotation axis of the stirring blades A3 to A5. The flow accompanied by this vortex mainly contributes to the mixing of the target material T. Further, the flow velocity is maximum in the vicinity of the stirring blades A3 to A5, particularly in the vicinity of the outer peripheral end 10. Such a locally fast flow velocity mainly contributes to dispersion of the target material T.

  FIG. 19 shows an analysis example using numerical fluid dynamics simulation for the stirring blade X (FIG. 9) having the same outer diameter as the stirring blades A3 to A5 under the same conditions as the fluid analysis examples shown in FIGS. Is shown. As shown in FIG. 19, the flow velocity is maximum near the outer peripheral end of the stirring blade X. Also, two vortices are observed on both the left and right sides of the rotation axis of the stirring blade X. However, in the region near the side wall of the container 81, the liquid surface of the target material T, and the bottom surface of the container 81, the flow velocity is remarkably small. From this, it can be seen that the mixing by the stirring blades A3 to A5 is appropriately performed in a wider range of the container 81 as compared with the mixing by the stirring blade X.

  As a factor that the degree of mixing by the stirring blades A3 to A5 is high, the contribution of the front curved portion 27 of each blade portion 20 can be cited as with the stirring blades A1 and A2. It is considered that the strong suction and smooth movement by the front curved portion 27 are causes for mixing of the entire target material T.

  Further, when the fluid analysis example of the stirring blades A3 and A4 shown in FIGS. 16 and 17 is compared with the fluid analysis example of the stirring blade A5 shown in FIG. 18, the thin tone region (the region where the flow velocity is fast) in FIGS. This is wider than the thin tone area in FIG. As this factor, as mentioned above, it is mentioned that stirring blade A3, A4 has the back curve part 28. FIG. That is, it is considered that the mixing of the entire target material T is promoted by the synergistic action of the suction enhancement by the front bending portion 27 and the discharge enhancement by the rear bending portion 28.

  20 to 23 show analysis examples using other numerical fluid dynamic simulations performed by the stirring blades A3 to A5 and the stirring blade X. FIG. The conditions of these analyzes are the same as in the case of FIGS. 16 to 19, the inner diameter of the container 81 is 210 mm, and the target material T is a high-viscosity non-Newtonian fluid having a liquid depth of 158 mm (sodium carboxymethyl cellulose 1.7 wt%) Is used. The stirring blades A3 to A5 and the stirring blade X are arranged in the approximate center of the target material T. The rotational peripheral speeds of the stirring blades A3 to A5 and the stirring blade X are 10 m / s. In these analysis examples, a plurality of granular markers are added to the target material T. Each black dot in the figure represents an individual marker. The number of markers is 1000. In the initial stage, the marker is arranged in a substantially disc-shaped region immediately above the stirring blades A3 to A5 and the stirring blade X. Specifically, the initial marker placement region has a depth of 40 to 50 mm from the liquid surface of the target material T, and in the lateral direction, is within a circle having a diameter of 60 mm centered on the rotation axis. The marker tracking time is from the time when the marker is present in the above-described initial range to 0.8168 s later, which corresponds to the time required for the stirring blades A3 to A5 and the stirring blade X to rotate 6.5 times.

  First, in the analysis examples (stirring blades A3 to A5) shown in FIGS. 20 to 22, the markers are distributed in a wider range of the target material T compared to the analysis example (stirring blade X) shown in FIG. In particular, in the analysis example shown in FIG. 23, there are almost no black spots indicating markers in the vicinity of the side surface of the container 81 or the liquid surface of the target material T. On the other hand, in the analysis examples shown in FIGS. 20 to 22, many markers exist near the side surface of the container 81 and the liquid surface of the target material T. This is considered to be the effect of the stirring blades A3 to A5 having the front curved portion 27 as described with reference to FIGS.

  Next, when the analysis example in FIG. 20 (stirring blade A3) is compared with the analysis example in FIG. 21 (stirring blade A4), there is a difference in the number of markers present below the stirring blade A3 and the stirring blade A4. Specifically, the number of markers existing below the stirring blade A3 is 110, whereas the number of markers existing below the stirring blade A4 is 47. This difference is thought to be due to the following reasons.

  The stirring blade A3 and the stirring blade A4 are the same in that the base portion 1 has a pair of upper and lower inclined surfaces 11 and a plurality of blade portions 20 are provided on each inclined surface 11. The target material T is discharged outward in the radial direction r by each blade portion 20, but the discharged flow also has a velocity component toward the blade group 2 located on the opposite side in the axial direction z. Yes. As described above, in the stirring blade A3, the upper and lower blade groups 2 are shifted from each other by a half pitch in the rotation direction θ. For this reason, in the stirring by the stirring blade A3, the axial z components of the target material T discharged from the upper and lower blade groups 2 are relatively less likely to interfere with each other. That is, in the axial direction z, the flow from one blade group 2 toward the other blade group 2 is not hindered. In observation of the mixed state using the stirring blade A3, a relatively large flow accompanied by a vortex moves in the axial direction z in the entire container 81 beyond the position where the stirring blade A3 is provided (the position of the outer peripheral end 10). It was confirmed that the phenomenon (that is, longitudinally traversing the inside of the container 81) occurs periodically. This is preferable for promoting the mixing of the entire target material T as compared with the mixed state in which vortex flows separated from each other in the axial direction z exist (without moving in the vertical direction). On the other hand, in the stirring blade A4, since the upper and lower blade groups 2 coincide with each other in the rotation direction θ, it is difficult to expect the same effect as the stirring blade A3. For this reason, it is considered that stirring with the stirring blade A3 moved more markers downward in the axial direction z.

  In addition, it is considered that the longitudinal flow in the container 81 generated by the stirring by the stirring blade A4 is weaker than the longitudinal flow by the stirring by the stirring blade A3. On the other hand, when the flows discharged from the upper and lower blade groups 2 merge, an effect of generating a flow in a wider range in the radial direction r can be expected. This is suitable for appropriately stirring the target material T when the inner diameter of the container 81 is large.

  Further, when the analysis example (stirring blade A3) in FIG. 20 is compared with the analysis example (stirring blade A5) in FIG. 22, the number of markers existing below the stirring blade A3 is 110, whereas the stirring blade A5 The number of markers present below is 72. As described above, this difference is considered to be an effect of the stirring blade A3 having the backward curved portion 28. In the stirring blade A5, since the upper and lower blade groups 2 are provided with a half-pitch shift in the rotational direction θ, a larger number of markers are moved downward than in the analysis example of the stirring blade A4. I understand.

  FIG. 24 shows a stirring device B3 using the stirring blade A3. The illustrated stirring device B3 includes two rotating shafts 82 and a stirring blade 84 in addition to the stirring blade A3.

  The two rotation shafts 82 are respectively driven to rotate by the drive unit 83. The length and rotation speed of the two rotation shafts 82 can be set as appropriate. In the illustrated example, the two rotation shafts 82 are parallel to each other, and the rotation shaft 82 provided at the center (plan view) of the container 81 is longer than the other rotation shaft 82. The stirring blade 84 is larger than the stirring blade A3 (in plan view) and is disposed near the bottom of the container 81. In a plan view, the center of the stirring blade 84 coincides with the center of the container 81. Note that the center of the stirring blade 84 may be arranged away from the center of the container 81 according to the size of the stirring blade 84 with respect to the container 81. The stirring blade 84 is provided for the purpose of promoting the mixing of the entire target material T in the container 81, for example.

  In the example shown in FIG. 24, the stirring blade A3 is provided at a position offset from the center of the container 81 in the plan view to the side wall of the container 81, and is positioned above the stirring blade 84 in the axial direction z. Yes. Further, the stirring blade 84 has a plurality of blades (two in the illustrated example) extending in the horizontal direction from the lower end of the central rotating shaft 82. Each blade has a length that does not interfere with the inner surface of the container 81, and is longer than the separation distance between the two rotating shafts 82 in the illustrated example. As an example, the number of rotations per unit time during driving is not particularly limited, and the central rotation shaft 82 (and hence the stirring blade 84) is the other rotation shaft 82 (and thus the stirring blade A3). Is set to be less.

  The dispersion degree and the degree of mixing of the target material T can also be improved by the stirring device B3 configured as described above. In addition, by using the stirring blade 84 and the stirring blade A3 in combination, the target material T accommodated in the larger-capacity container 81 can be appropriately mixed and dispersed.

  As described above, according to the stirring blades A1 to A5 of the present disclosure, it is possible to significantly improve the degree of mixing of the target material T compared to the stirring blade X (FIG. 9). In order to improve the degree of dispersion of the target material T, it is preferable to increase the rotation speed of the stirring blades A1 to A5. In this respect, the mixing effect of the target material T by the stirring blades A1 to A5 can be sufficiently maintained even if the rotation speed of the stirring blades A1 to A5 is increased. Therefore, according to the stirring blades A1 to A5 and the stirring devices B1 and B3, both the degree of dispersion and the degree of mixing of the target material T can be improved.

  The stirring blade and the stirring device according to the present disclosure are not limited to the above-described embodiment. The specific configuration of each part of the stirring blade and the stirring device according to the present disclosure can be varied in design in various ways.

Claims (8)

A stirring blade rotating around an axis,
The base,
A plurality of first blade portions provided on the first side of the base portion and arranged around the axis, and
Each of the plurality of first blade portions includes an inner end in a radial direction perpendicular to the axial center, and a forward curved portion connected to the inner end and protruding forward in the rotation direction.   Each said 1st blade | wing part is a stirring blade of Claim 1 which has the back curve part which is connected to the said radial direction outward with respect to the said front curve part, and is convex in the said rotation direction.   3. The stirring blade according to claim 1, wherein each of the first blade portions is inclined so as to be positioned forward of the rotation direction as the distance from the base portion increases in a direction parallel to the axis.   The stirring blade according to claim 3, wherein an inclination angle of each of the first blade portions with respect to a direction parallel to the axis is larger toward an inner side in the radial direction. In the configuration further comprising a plurality of second blade portions,
The base portion has a second side opposite to the first side, and the plurality of second blade portions are provided on the second side and arranged around the axis. The stirring blade according to any one of 1 to 4.   The stirring blades according to claim 5, wherein the plurality of first blade portions are different in position in the rotation direction from the plurality of second blade portions.   The base portion has a first inclined surface and a second inclined surface that are tapered in opposite directions, and the plurality of first blade portions are provided on the first inclined surface, The stirring blade according to claim 5 or 6, wherein the plurality of second blade portions are provided on the second inclined surface. A stirring blade according to any one of claims 1 to 7,
A container for containing a stirring object;
A rotating shaft inserted into the container and to which the stirring blade is attached;
A stirring device.