Certain embodiments of the present invention relate to a stirring device suitable for stirring a fluidic stirring object having a specific viscosity.
For example, in order to form an emulsified liquid used for hair care products or skin care products, that is, an emulsified liquid in which an oil phase (for example, silicone oil) is refined to be dispersed into an aqueous phase, an emulsification method for applying a shear force to the oil phase to refine the oil phase is known. For the emulsified liquid, a stable state where dispersed particles are not separated needs to be maintained over a long period of time. In a case of a low-viscosity emulsified liquid, the dispersed particles need to have a submicron particle size or a smaller particle size.
There are various types as an emulsification device for performing emulsification. For example, a rotor-stator type device is used as a high-shear blade used for applying the shear force to the oil phase and used for producing the low-viscosity emulsified liquid.
As the device used for producing a high-viscosity emulsified liquid, there is a device in the related art disclosed by the present applicant. This device is configured as follows. A ribbon impeller that performs entire circulation inside tank supplies a liquid to a dispersion blade that rotates at a high speed. The shear force can be applied to the liquid from the dispersion blade. According to this configuration, it is possible to refine an ultra-high-viscosity stirring object which is less likely to be refined in the related art.
According to an embodiment of the present invention, there is provided a stirring device including a stirring tank including an inner peripheral wall which is circular in cross section, at least one circulating impeller and at least one dispersion blade which are located inside the stirring tank and rotatable around a vertical axis independently of each other, and a guide ring disposed near a radially outer side of the dispersion blade. Rotation centers of the circulating impeller and the dispersion blade are concentric with each other. The circulating impeller is disposed along the inner peripheral wall of the stirring tank, and rotates around the vertical axis to format least a downward flow in a stirring object existing inside the stirring tank. The dispersion blade rotates to apply a shear force to the stirring object, and is disposed at a radially inner position of the stirring tank from the circulating impeller, and at a position in contact with a flow of the stirring object, which is formed by the circulating impeller. The guide ring includes an inner peripheral surface facing an outer peripheral edge of the dispersion blade.
In the rotor-stator type device, a vane rotates at a high speed as in a centrifugal pump to suction the liquid and to discharge the liquid. The rotor-stator type device has a function of applying the shear force to the liquid by rotating at the high speed while circulating the liquid. However, as in a case of the centrifugal pump, when a viscosity of the liquid increases, a negative pressure portion is generated on a rear side of the vane, thereby causing a so-called “cavitation phenomenon” to occur. Consequently, an application limit is a viscosity of approximately 1,000 cP. Therefore, in a case where the viscosity is 10,000 cP or higher, the stirring object is not continuously supplied (suctioned) into the device, and a phenomenon occurs in which the device “idles”.
According to the device disclosed in the related art, an emulsification operation can be performed to some extent in a case where the viscosity is lower than 10,000 cP. However, the inventor of the present application has found the followings. When a specific emulsification operation is performed using the device, the dispersed particles are less likely to be separated over a long period of time. Consequently, the device is insufficient in producing a stable emulsified liquid. The reason is considered as follows. It is assumed that the stirring object of the device has an ultra-high viscosity exceeding 100,000 cP. When the viscosity is lower than the assumed viscosity, the shear force is not sufficiently applied to the stirring object. Accordingly, the stirring object is insufficiently refined. The reason is also considered as follows. Since the viscosity is relatively low, compared to the ultra-high-viscosity stirring object, a discharge amount from the dispersion blade increases due to the low viscosity. On the other hand, a supply flow rate from the ribbon impeller decreases. Accordingly, a flow of the stirring object inside tank becomes unbalanced.
As described above, a stirring (emulsification) device suitable for the stirring object having a high viscosity, specifically, a viscosity of 10,000 cP to 100,000 cP (viscosity in this range is defined as a “high viscosity” in the present application) does not exist in the related art.
Under the above-described circumstances, in a jobsite for performing the emulsification operation, in some cases, the emulsification operation is performed in a state where the viscosity of the stirring object is lowered by raising an operation temperature once. However, when this emulsification operation is performed, there is a disadvantage in that a large amount of power and a longer processing time are required for heating and cooling, or there is a disadvantage in that a long time is required for cleaning work after the operation since the number of components in the device increases. Therefore, it is desirable to use a device capable of performing the emulsification operation at a room temperature as it is.
There is a need for a stirring device particularly suitable for a high-viscosity stirring object.
In addition, the dispersion blade may include a rotating plate-shaped part, shear teeth disposed in an outer peripheral edge of the plate-shaped part at an interval in a circumferential direction, and at least one fin part protruding at least upward or downward from the plate-shaped part.
In addition, the dispersion blade may include at least one through-hole adjacent to the fin part and penetrating the plate-shaped part.
In addition, a vertical dimension on the inner peripheral surface of the guide ring may be larger than a vertical dimension in the outer peripheral edge of the dispersion blade.
In addition, the stirring device may further include a baffle located above or below the guide ring. The baffle may guide the stirring object to which the shear force is applied by the dispersion blade, to a radially outer position from an area surrounded by the inner peripheral surface of the guide ring.
In addition, a radial distance between the outer peripheral edge of the dispersion blade and the inner peripheral surface of the guide ring may exceed 0%, and may be equal to or smaller than 10% of a diameter of the inner peripheral wall in the stirring tank.
In addition, a vertical dimension on the inner peripheral surface of the guide ring may exceed 0%, and may be equal to or smaller than 25% of a diameter of the inner peripheral wall in the stirring tank.
Hereinafter, a stirring device according to an embodiment of the present invention will be described. A preferred application of a stirring device 1 according to the present embodiment is emulsification, and the emulsification will be described below. However, the application of the stirring device 1 is not limited only to the emulsification, and the stirring device 1 is applicable to various applications. As a stirring object in a case of the emulsification, for example, various materials for cosmetics (hair care products, skin care products, and toothpaste) and foods (dressing) can be used. However, the examples are not limited thereto. The stirring object has fluidity, and examples thereof include a fluid (liquid or gas), a solid in a form of particles or powder, and a mixture thereof.
The stirring device 1 according to the present embodiment is suitable for a high-viscosity (viscosity of 10,000 cP to 100,000 cP) stirring object. However, the present invention can be applied to the stirring object having a viscosity of 1,000 cP to 1,000,000 cP. The unit “cP” used in the description herein is “mPa·s” when converted to an SI unit system.
The stirring device 1 according to the present embodiment includes a circulating impeller 3, a dispersion blade 4, a guide ring 5, and a baffle 6 inside a stirring tank 2 capable of accommodating the stirring object. However, the baffle 6 is not essential in the present invention, and may not be provided. The circulating impeller 3 and the dispersion blade 4 are separately driven (multi-axis driving) by a driving part such as a motor disposed outside the stirring tank 2. In this manner, both of these are rotatable independently of each other. Therefore, both of these rotate at a suitable rotation speed in accordance with properties of the stirring object. In a case where the stirring device 1 is used for the emulsification, the circulating impeller 3 mixes and emulsifies the stirring object to form droplets. The dispersion blade 4 refines the droplets in an emulsified liquid into a small size. More specifically, the dispersion blade 4 refines the droplets by applying a shear force to a component that is in a dispersed phase in the stirring object. For example, the emulsified liquid produced by the stirring device 1 according to the present embodiment is an O/W type emulsified liquid, and a dispersed phase thereof is an oil phase. Conversely, the emulsified liquid can be a W/O type emulsified liquid, and the dispersed phase can be an aqueous phase.
The stirring tank 2 is a container having an inner peripheral wall 2a which is circular in cross section. An upper part of the stirring tank 2 is a cylindrical straight body part 21, and a lower part thereof is a frusto-conical throttle part 22. The straight body part 21 and the throttle part 22 are integrally formed. An inner diameter of the straight body part 21 is constant in an upward-downward direction. The throttle part 22 has an inner diameter which decreases downward. The inner diameter of the stirring tank 2 is set in this way. Accordingly, an induced flow F (refer to
In the present embodiment, a ribbon impeller is used as the circulating impeller 3. The circulating impeller 3 is disposed along the inner peripheral wall 2a of the stirring tank 2. A blade diameter (diameter) of the circulating impeller 3 can be set to 0.9 to 0.9999 as a ratio to the inner diameter of the inner peripheral wall 2a in the stirring tank 2. The circulating impeller 3 rotates around a vertical axis to form an induced flow F in the stirring object existing inside the stirring tank 2. This induced flow F is a partial flow that largely flows into the whole stirring tank 2. Ina case where the stirring device 1 is used for emulsification, the stirring object is mixed and emulsified by the induced flow F, thereby forming droplets.
The circulating impeller 3 according to the present embodiment is disposed along the inner peripheral wall 2a of the stirring tank 2, and includes two circulating impeller bodies 31 and 31 having a predetermined width, and a plurality of support rods 32 and 32 that support the two circulating impeller bodies 31 and 31 at a radially inner position. Each circulating impeller body 31 has a curved band shape. Each circulating impeller body 31 includes an upper blade 311 and a lower blade 312. The upper blades 311 are disposed at an equal interval in a circumferential direction of the straight body part 21 (interval of 180° in the present embodiment), and the lower blades 312 are disposed at an equal interval in a circumferential direction of the throttle part 22 (interval of 180° in the present embodiment). The two circulating impeller bodies 31 and 31 are rotationally symmetrically disposed at every interval of 180° across a cross-sectional center of the stirring tank 2.
The upper blade 311 is disposed at a prescribed distance from the inner peripheral wall of the straight body part 21 in the stirring tank 2, and extends downward from above while being inclined at a prescribed angle in the circumferential direction. As the upper blade 311 rotates in the straight body part 21, the upper blade 311 scrapes down the stirring object, and forms the swirling downward induced flow F. The lower blade 312 is located substantially along a surface shape of the inner peripheral wall of the throttle part 22 in the stirring tank 2. As illustrated in
The upper blade 311 and the lower blade 312 are connected to each other in a joining portion 313 illustrated in
As the lower blade 312 rotates in the rotation direction R3 in the throttle part 22, a flowing direction of the swirling downward induced flow F formed by the upper blade 311 is changed so that the induced flow F is directed downward while being directed in a radially inward direction as illustrated in
A downward facing surface of each circulating impeller body 31 is a portion that acts on the stirring object to be pushed downward. Therefore, in order to uniformly form the induced flow F, it is preferable that the downward surfacing surface of each circulating impeller body 31 is a curved surface having no step as far as possible. With regard to the prescribed distance, the inner peripheral wall 2a of the stirring tank 2 and the outer peripheral edge of each circulating impeller body 31 in the present embodiment have a horizontal distance of 1% to 3%, as a ratio to the inner diameter of the straight body part 21 in the stirring tank 2. However, this distance can be appropriately set in accordance with properties of the stirring object. In this way, each circulating impeller body 31 is disposed near the inner peripheral wall 2a of the stirring tank 2. Accordingly, each circulating impeller body 31 can reliably form the induced flow F of the stirring object along the inner peripheral wall 2a of the stirring tank 2.
A center axis or a center blade to which the stirring object can adhere does not exist at an internal center of the stirring tank 2. Accordingly, it is possible to prevent the stirring object from adhering to a shaft and from staying in the stirring tank 2. A width dimension of each circulating impeller body 31 is not limited to the above-described ratio, and can be appropriately set in accordance with the properties of the stirring object.
The circulating impeller bodies 31 and 31 and the support rods 32 and 32 in the circulating impeller 3 are integrated with each other by welding. Each support rod 32 is a straight rod extending in an upward-downward direction, and fixes the circulating impeller body 31 on the upper and lower sides. Each support rod 32 is connected to a circulating impeller driving part (not illustrated) disposed above the stirring tank 2 via a circulating impeller driving shaft 34. In this manner, each circulating impeller body 31 is rotatable around the vertical axis extending in the upward-downward direction via each support rod 32. A dispersion blade driving shaft 43 extending in the upward-downward direction passes through an inner portion of the radially inner end portion of the lower blade 312. As illustrated in
The circulating impeller 3 rotates in the rotation direction R3 which is a counterclockwise direction in a plan view. A rotation speed is lower than a rotation speed of the dispersion blade 4. The rotation causes each circulating impeller body 31 to push the stirring object downward. Therefore, as illustrated in
The dispersion blade 4 rotates to apply a shear force to the stirring object. In a case where the stirring device 1 is used for the emulsification, the droplets formed by the circulating impeller 3 are divided and refined by the shear force.
As illustrated in
The plate-shaped part 41 may have a flat plate shape. However, as illustrated in
Each fin part 44 according to the present embodiment has a flat plate shape perpendicular to the plate-shaped part 41. In the illustrated example, a plurality of (specifically, four) the fin parts 44 are rotationally symmetrically disposed, and all protrude upward. However, the upward protrusion is merely an example for convenience of description, and the example is not limited thereto. The plurality of fin parts 44 and 44 may all protrude downward of the plate-shaped part 41, or may alternately protrude upward and downward in the circumferential direction.
As illustrated in
In the dispersion blade 4 according to the present embodiment, the fin part 44 is formed by cutting out and raising a part of the plate-shaped part 41. Therefore, as the fin part 44 is formed, each through-hole 45 penetrating upward and downward is formed adjacent to a base end side position of each fin part 44 in the plate-shaped part 41. The plate-shaped part 41 is located forward (rotation destination direction) with reference to the rotation direction R4 (illustrated in
Since the dispersion blade 4 rotates, the plate-shaped part 41 is located on a side opposite to a side pushing the stirring object. Accordingly, a negative pressure is generated in each through-hole 45. The stirring object around the generated negative pressure is suctioned. As a result, a flow Fb passing through the plate-shaped part 41 in the upward-downward direction can be generated (
The diameter of the dispersion blade 4 is set to 0.2 to 0.6, preferably 0.3 to 0.5, as a ratio to the inner diameter of the straight body part 21 in the stirring tank 2. In this manner, the stirring object can be guided to the dispersion blade 4 in a state where a rising force of the induced flow F is strong (a state where the rising force is not attenuated).
Since the dispersion blade 4 rotates, each shear tooth 42 collides with the stirring object. At this time, a leading edge portion of each shear tooth 42 in the rotation direction can apply the shear force to the stirring object. That is, upper and lower areas near the dispersion blade 4 including a periphery of a rotation locus of each shear tooth 42 have a high shear field. Specifically, the shear force is applied between two shear teeth 42 and 42 adjacent in the circumferential direction.
The dispersion blade driving shaft 43 extending downward is connected to the dispersion blade 4. Although not illustrated, apart between the stirring tank 2 and the dispersion blade driving shaft 43 is sealed so that the stirring object does not leak. The dispersion blade driving shaft 43 is connected to a dispersion blade driving part (not illustrated) disposed below the stirring tank 2. In this manner, the dispersion blade 4 can be rotated around the vertical axis extending in the upward-downward direction.
As described above, a circulating impeller driving part (not illustrated) for rotating the circulating impeller 3 is located above the stirring tank 2. A dispersion blade driving part for rotating the dispersion blade 4 is located below the stirring tank 2. Therefore, a shaft length of the driving shafts 34 and 43 connecting the respective driving parts and the respective blades can be reduced. It is possible to prevent the shafts from being deflected or deviated. Accordingly, it is possible to prevent vibration (resonance) when the shafts are driven. In particular, the shaft length of the dispersion blade driving shaft 43 can be reduced for the dispersion blade 4. Accordingly, the dispersion blade 4 can rotate at a high speed. It is possible to prevent the dispersion blade driving shaft 43 from having a fatigue failure caused by the vibration.
A dimension of the dispersion blade 4 from a bottom part 24 of the stirring tank 2 is smaller than a dimension of the inner diameter of the straight body part 21 in the stirring tank 2. The dispersion blade 4 is located at a radially inner position of the stirring tank 2 from the circulating impellers 3. As illustrated in
Here, as described above, since the circulating impeller 3 rotates, the induced flow F that flows downward along the inner peripheral wall 2a of the stirring tank 2 is first generated in the straight body part 21 in the stirring object. The throttle part 22 is formed in the lower part of the stirring tank 2, and the lower blade 312 of the circulating impeller 3 rotates in the throttle part 22. Accordingly, as illustrated in
In this way, the direction of the induced flow F is changed by the circulating impeller 3 and the inner peripheral wall 2a of the stirring tank 2, and the stirring object is wrapped inside in the stirring tank 2. Accordingly, the stirring object can be actively supplied to the dispersion blade 4. In a case of the emulsification, oil droplets or water droplets can be reliably refined through the shearing performed by the dispersion blades 4.
As described above, it is preferable that the stirring object is supplied to the dispersion blade 4 by the circulating impeller 3 at a position close to the rotation center (vertical axis) of the dispersion blade 4. The reason is as follows. The stirring object can be supplied to a position apart from each shear tooth 42 so that the stirring object supplied by the circulating impeller 3 is not rebounded due to the stirring object discharged by each shear tooth 42 until the stirring object reaches the dispersion blades 4. Particularly, this configuration is effective in a case where the stirring object is a highly thixotropic fluid.
Here, in the present embodiment, the circulating impeller 3 is the ribbon impeller. Therefore, for example, in order to disperse the droplets into the emulsified liquid, it is possible to provide a combination of the circulating impeller 3 and the dispersion blade 4 which include blades having a shape most suitable for refining the oil phase in the stirring object.
Both the rotation center of the circulating impeller 3 and the rotation center of the dispersion blade 4 pass through the cross-sectional center of the stirring tank 2. Compared to a form in which the rotation centers of the respective blades are shifted from each other, a configuration is adopted so that the rotation centers are concentric with each other as in the present embodiment. In this manner, the distances from the rotation center of the respective blade 3 and 4 to the inner peripheral wall 2a of the stirring tank 2 can be equal. Therefore, the induced flow F of the stirring object flowing from the circulating impeller 3 toward the dispersion blade 4 is uniform in the circumferential direction of the stirring tank 2. Therefore, a horizontal load applied to the dispersion blade 4 can be reduced. Accordingly, for example, it is possible to prevent the dispersion blade driving shaft 43 from being broken.
The guide ring 5 is a ring-shaped body disposed near a radially outer side of the dispersion blade 4. As illustrated in
The guide ring 5 has the inner peripheral surface 5a facing the outer peripheral edge 4a of the dispersion blade 4. In the present embodiment, the upper end of the inner peripheral surface 5a is located above the upper end of the shear tooth 42 in the dispersion blade 4, and the lower end of the inner peripheral surface 5a is located below the lower end of the shear tooth 42 in the dispersion blade 4. In the guide ring 5, the inner peripheral surface 5a and the outer peripheral surface are vertical surfaces, and the upper surface and the lower surface are inclined surfaces. A longitudinal sectional shape of the inner peripheral surface 5a is a parallelogram located above the outer peripheral surface. Since the guide ring 5 has this shape, an opening area of the lower end part of the guide ring 5 can be enlarged. Accordingly, the guide ring 5 is less likely to hinder the induced flow F of the stirring object directed from the circulating impeller 3 to the dispersion blade 4. Since the upper surface is an inclined surface, the stirring object is not accumulated in an area above the upper surface.
The shape of the guide ring 5 is not limited thereto. The longitudinal sectional shape can be a rectangular shape or a square shape, or a trapezoidal shape in which a longitudinal dimension of the inner peripheral surface 5a is larger than a longitudinal dimension of the outer peripheral surface. Conversely, the longitudinal sectional shape can be a trapezoidal shape in which a longitudinal dimension of the inner peripheral surface 5a is smaller than a longitudinal dimension of the outer peripheral surface. The longitudinal sectional shape can be any desired shape other than the square shape. Although the guide ring 5 according to the present embodiment is solid, the guide ring 5 may be hollow. A thickness dimension in the radial direction is not particularly limited as long as the guide ring 5 can withstand the pressure received from the stirring object. The guide ring 5 according to the present embodiment is formed in a shape continuous in the circumferential direction (ring-shaped body). However, the present invention is not limited thereto, and the guide rings 5 may be intermittently disposed at an interval in the circumferential direction.
The guide ring 5 is disposed near the radially outer side of the dispersion blade 4 in this way. Accordingly, as illustrated in
A vertical dimension 5h on the inner peripheral surface 5a of the guide ring 5 is set to be larger than a vertical dimension 4h in the shear tooth 42 on the outer peripheral edge 4a of the dispersion blade 4. According to this dimensional relationship, it is possible to largely secure an area between the inner peripheral surface 5a of the guide ring 5 and the outer peripheral edge 4a of the dispersion blade 4, which is an area where a strong shear force can be applied to the stirring object. However, the dimensional relationship is not limited thereto. The vertical dimension 5h on the inner peripheral surface 5a of the guide ring 5 can be set to be the same as or smaller than the vertical dimension 4h in the shear tooth 42 on the outer peripheral edge 4a of the dispersion blade 4.
A distance between the inner peripheral surface 5a of the guide ring 5 and the outer peripheral edge 4a of the dispersion blade 4 may be any desired distance as long as the distance can form a high shear rate area as illustrated in
The baffle 6 is a plate-shaped body located above or below the guide ring 5. However, any member other than the plate-shaped body can be adopted. Various shapes can be used even if the baffle 6 is the plate-shaped body. In the present embodiment, as illustrated in
Here, the present inventor performed emulsification experiments by producing experimental stirring devices in respective forms illustrated in
Inner diameter of stirring tank: φ200 mm
Liquid volume: 2.5 L (after emulsification)
Aqueous phase: 1.5 wt % CMC (carboxymethyl-cellulose) aqueous solution (“Cellogen MP-60” manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.)
Oil phase: Liquid paraffin 125 g
Emulsifier: nonionic surfactant 0.4 g (“Tween 80” manufactured by Kishida Chemical Co., Ltd.)
Liquid viscosity: CMC aqueous solution 15,000 cP (shear rate y=10(1/s)), final emulsified liquid 11,000 cP (shear rate y=10(1/s))
Outer diameter of dispersion blade: 80 mm
Rotation speed of dispersion blade: 3600 rpm
Rotation speed of ribbon impeller: 40 rpm
As illustrated in
As illustrated in
As illustrated in
The present inventor performed an emulsification experiment by producing an experimental stirring device in the form illustrated in
First, in the experimental stirring device, the distance (gap) between the outer peripheral edge 4a of the dispersion blade 4 and the inner peripheral surface 5a of the guide ring 5 is set in the following four patterns (A) to (D). The vertical dimension 5h on the inner peripheral surface 5a of the guide ring 5 is set to a prescribed dimension (35 mm). (A) Inner diameter of guide ring 5 is 88 mm (gap is 4 mm) (B) Inner diameter of guide ring 5 is 98 mm (gap is 9 mm) (C) Inner diameter of guide ring 5 is 106 mm (gap is 13 mm) (D) Inner diameter of guide ring 5 is 116 mm (gap is 18 mm)
The results are illustrated by a graph in
Next, in the experimental stirring device, the vertical dimension 5h on the inner peripheral surface 5a of the guide ring 5 is set in the following four patterns (E) to (H). The diameter of the inner peripheral surface 5a of the guide ring 5 (inner diameter of the guide ring 5) is set to a prescribed dimension (106 mm). The vertical dimension 4h of the outer peripheral edge 4a of the dispersion blade 4 in the shear tooth 42 is set to a prescribed dimension (22 mm). As illustrated in
The results are illustrated by a graph in
The induced flow F of the stirring object formed by the circulating impeller 3 can reach the dispersion blade 4 by the stirring device 1 according to the present embodiment configured as described above. Accordingly, the stirring object is continuously supplied from the circulating impeller 3 to the dispersion blade 4. Therefore, a space is less likely to be formed around the rotating dispersion blade 4. Furthermore, the strong shear force can be applied to the stirring object in the area between the dispersion blade 4 and the guide ring 5. Furthermore, the flow of the stirring object inside the tank can be satisfactorily balanced by the baffle 6. Therefore, in the high viscosity area (viscosity of 10,000 cP to 100,000 cP), it is possible to produce a stable emulsified liquid that is not separated over a long period of time. Moreover, in the related art, in some operation cases, the viscosity is lowered by raising the temperature of the stirring object. However, the stirring device 1 according to the present embodiment can be operated at room temperature. Therefore, it is possible to solve the following disadvantages in the related art. A large amount of power and a longer processing time are required for heating and cooling, or a long time is required for cleaning work since the number of components in the device increases.
The stirring device according to the present invention is not limited to the embodiment. The present invention can be modified in various ways within the scope not departing from the concept of the present invention.
For example, the circulating impeller 3 is the ribbon impeller in the embodiment, but is not limited thereto. The circulating impeller 3 can be realized in various forms as long as the circulating impeller 3 adopts the following configuration. One or more inclined circulating impeller bodies 31 are disposed inside the stirring tank 2. As each of the circulating impeller bodies 31 moves (rotates in the embodiment) inside the stirring tank 2, the stirring object is pushed downward. Each of the circulating impeller bodies 31 may have a curved plate (band) shape as in the embodiment, or may have a flat plate shape.
In a case where the ribbon impeller is used as the circulating impeller 3, the present invention is not limited to the following configuration. As in the embodiment, the two circulating impeller bodies 31 are disposed for the upper blade 311 at an equal interval (interval of 180° in the embodiment) in the circumferential direction, and are disposed for the lower blade 312 at an equal interval (interval of 180° in the embodiment) in the circumferential direction. A disposition range of the circulating impeller bodies 31 can be set to any desired angle of 90° to 360°, and the number of the circulating impeller bodies 31 can be set to any desired number of one, three, or more.
A plurality of dispersion blades 4 can be disposed in multiple stages in the upward-downward direction. In this case, a shape of the dispersion blade 4 in each stage may vary. A plurality of circulating impellers 3 can be provided. In a case where the plurality of dispersion blades 4 are disposed in multiple stages in the upward-downward direction, it is preferable that a plurality of guide rings 5 are disposed corresponding to the dispersion blades 4 in each stage, instead of continuously providing the guide rings 5 in the upward-downward direction.
In the dispersion blade 4 according to the embodiment, the through-hole 45 is formed together with the fin part 44 by cutting out a part of the plate-shaped part 41. However, for example, only the fin part 44 can be formed by welding a separate plate-shaped body to the plate-shaped part 41.
The stirring device 1 according to the present embodiment performs batch processing. However, without being limited thereto, the stirring device 1 can perform continuous processing by continuously supplying the stirring object into the stirring tank.
A configuration and an operation of the embodiment will be summarized below. In the embodiment, the stirring device 1 includes the stirring tank 2 having the inner peripheral wall 2a which is circular in cross section, at least one ribbon impeller 3 and at least one dispersion blade 4 which are located inside the stirring tank 2 and rotatable around the vertical axis independently of each other, and the guide ring 5 disposed near the radially outer side of the dispersion blade 4. Rotation centers of the ribbon impeller 3 and the dispersion blade 4 are concentric with each other. The ribbon impeller 3 is disposed along the inner peripheral wall 2a of the stirring tank 2, and rotates around the vertical axis to form at least the downward flow F in the stirring object existing inside the stirring tank 2. The dispersion blade 4 rotates to apply the shear force to the stirring object, and is disposed at the radially inner position of the stirring tank 2 from the ribbon impeller 3, and at the position in contact with the flow F of the stirring object, which is formed by the ribbon impeller 3. The guide ring 5 has the inner peripheral surface 5a facing the outer peripheral edge 4a of the dispersion blade 4.
According to this configuration, the dispersion blade 4 rotates inside the guide ring 5. In this manner, the strong shear force can be applied to the stirring object between the inner peripheral surface 5a in the guide ring 5 and the outer peripheral edge 4a of the dispersion blade 4. Moreover, the stirring object can be continuously supplied to the dispersion blade 4 by the ribbon impeller 3. Accordingly, the flow of the stirring object inside the tank can be satisfactorily balanced.
The dispersion blade 4 can include the rotating plate-shaped part 41, the shear teeth 42 and 42 disposed in the outer peripheral edge of the plate-shaped part 41 at an interval in the circumferential direction, and at least one fin part 44 protruding at least upward or downward from the plate-shaped part 41.
According to this configuration, the fin part 44 in the dispersion blade 4 can generate a strong flow in the stirring object near the plate-shaped part 41.
The dispersion blade 4 can include at least one through-hole 45 adjacent to the fin part 44 and penetrating the plate-shaped part 41.
According to this configuration, the negative pressure is generated in the through-hole 45 by the fin part 44 in the dispersion blade 4. In this manner, a flow that passes through the plate-shaped part 41 in the upward-downward direction can be generated in the stirring object.
The vertical dimension 5h of the guide ring 5 on the inner peripheral surface 5a may be larger than the vertical dimension 4h of the outer peripheral edge 4a of the dispersion blade 4.
According to this configuration, it is possible to largely secure an area between the inner peripheral surface 5a of the guide ring 5 and the outer peripheral edge 4a of the dispersion blade 4, which is an area where a high shear force can be applied to the stirring object.
In addition, a baffle 6 located above or below the guide ring 5 is provided, and the baffle 6 guides the stirring object to which the shear force is applied by the dispersion blade 4 to the radially outer position from an area surrounded by the inner peripheral surface 5a of the guide ring 5.
According to this configuration, the stirring object can be continuously guided to the radially outer position from the area surrounded by the inner peripheral surface 5a of the guide ring 5 by the baffle 6. Accordingly, the flow of the stirring object inside the tank is more satisfactorily balanced.
The radial distance G between the outer peripheral edge 4a of the dispersion blade 4 and the inner peripheral surface 5a of the guide ring 5 can exceed 0%, and can be equal to or smaller than 10% of the diameter (inner diameter) D2a of the inner peripheral wall 2a in the stirring tank 2.
According to this configuration, for example, in a case where the stirring device 1 is used for the emulsification, the particle size of the particles dispersed in the processed emulsified liquid can be refined.
The vertical dimension 5h on the inner peripheral surface 5a of the guide ring 5 can exceed 0% and can be equal to or smaller than 25% of the diameter D2a of the inner peripheral wall 2a in the stirring tank 2.
According to this configuration, for example, in a case where the stirring device 1 is used for the emulsification, the particle size of the particles dispersed in the processed emulsified liquid can be refined.
In the embodiment, the strong shear force can be applied to the stirring object. Moreover, the flow of the stirring object inside the tank can be satisfactorily balanced. Therefore, it is possible to provide the stirring device particularly suitable for the high-viscosity stirring object.
It should be understood that the invention is not limited to the above-described embodiment, but may be modified into various forms on the basis of the spirit of the invention. Additionally, the modifications are included in the scope of the invention.
Number | Date | Country | Kind |
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2017-215575 | Nov 2017 | JP | national |
The contents of Japanese Patent Application No. 2017-215575, and of International Patent Application No. PCT/JP2018/041074, on the basis of each of which priority benefits are claimed in an accompanying application data sheet, are in their entirety incorporated herein by reference).
Number | Date | Country | |
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Parent | PCT/JP2018/041074 | Nov 2018 | US |
Child | 16848998 | US |