EP3031519B1

EP3031519B1 - Stirrer

Info

Publication number: EP3031519B1
Application number: EP14834280.1A
Authority: EP
Inventors: Hiroo HORIGUCHI; Shoji Morinaga; Ryuichi Yatomi
Original assignee: Sumitomo Heavy Industries Ltd; Sumitomo Heavy Industries Process Equipment Co Ltd
Current assignee: Sumitomo Heavy Industries Ltd; Sumitomo Heavy Industries Process Equipment Co Ltd
Priority date: 2013-08-07
Filing date: 2014-07-30
Publication date: 2021-03-03
Anticipated expiration: 2034-07-30
Also published as: CN205667803U; JP6109006B2; TW201515694A; JP2015033658A; WO2015019914A1; KR20160001226U; TWM495896U; EP3031519A1; KR200487605Y1; EP3031519A4

Description

Cross-Reference of Related Application

Priority is claimed to Japanese Patent Application No. 2013-164538, filed August 7, 2013 .

Technical Field

The present invention relates to a stirrer targeting the mixture of an object to be stirred.

Background Art

In the related art, a stirrer provided with a cylindrical stirred tank, a stirring shaft arranged at a central part of the stirred tank, and a stirring impeller attached to a lower part side of the stirring shaft is known as a stirrer that stirs an object to be stirred. Aplurality of blades are provided along a circumferential direction of the stirring shaft in the stirring impeller.
If the stirring shaft rotates around an axis center, the stirring impeller rotates with the stirring shaft. The plurality of blades of the stirring impeller revolve within the stirred tank to make an object to be stirred receive by the blades flow, and shear the object to be stirred with a rotating flow generated by the rotation of the stirring impeller or with the blades themselves.
As the stirring impeller having such a function, there is a stirring impeller specialized for shear performance for shearing an object to be stirred, and a stirring impeller specialized for circulation performance for making an object to be stirred flow to be circulated.
As the stirring impeller specialized for the shear performance, for example, there are many stirring impellers, which make the object to be stirred received by the blades flow in a radial direction of the stirring shaft, such as a concave impeller in which plate-like blades are formed in a concave shape. These stirring impellers are specialized for shearing the object to be stirred near the blades to subdivide the object to be stirred (for example, refer to Japanese Unexamined Patent Application Publication No. 2003-210903 ).
As the stirring impeller specialized for the circulation performance, for example, there are many stirring impellers, which make the object to be stirred received by blades flow downward, such as an axial-flow impeller type stirring impeller. These stirring impellers are specializing for circulating the object to be stirred within the stirred tank (for example, refer to Japanese Unexamined Patent Application Publication No. H9-187636 ) .
The mixing performance of the object to be stirred by a stirring impeller is estimated from both performances of the shear performance and the circulation performance.
Document US 2005 0007874 A1 describes a stirrer comprising a tank, a shaft rotatably mounted in the tank and a plurality of blades being directly mounted to a hub which is attached to the shaft. The documents EP 0 441 505 A1 which discloses a stirrer according to the preamble of claim 1, and WO 2012/060372 A1 each disclose stirrers with blades that are attached to a shaft by means of connecting arms.

Summary of Invention

Technical Problem

Thus, the invention has been made in view of this problem, and provides a stirrer having a stirring impeller that is excellent in both performances of shear performance and circulation performance.

Solution to Problem

A stirrer of the invention is a stirrer according to claim 1. The stirrer includes a stirred tank that contains an object to be stirred; a stirring shaft rotatably attached within the stirred tank; and one or more stirring impellers attached to the stirring shaft. The stirring impellers have a plurality of blades that are attached respectively to tip parts of a plurality of support arms. Each of the plurality of support arms is in an elongated and tabular shape. A cylindrical boss is attached to the stirring shaft, the plurality of support arms protrude in a radial direction of the stirring shaft from the boss, and the support arms are fixed to the boss so that any one of a side surface, an upper surface, and a lower surface of the support arm inclines from a horizontal plane. The blades have a blade body and a groove that opens in a rotational direction. The groove extends in a direction intersecting a direction passing through a rotation radius centered on an axial center of the stirring shaft.
Additionally, as one aspect of the invention, the direction in which the groove extends may incline at a predetermined angle in the rotational direction with respect to the axial center direction of the stirring shaft.
Additionally, as another aspect of the invention, the groove may be formed in a semicircular shape in a sectional view.
Additionally, as still another aspect of the invention, the stirring impellers may be provided in two or more stages in the stirring shaft.
Additionally, as still another aspect of the invention, each of the stirring impellers may be attached to the stirring shaft so that the blades of each of the stirring impellers are arranged at positions shifted in the circumferential direction of the stirring shaft from the positions of the blades of another stirring impeller.
Additionally, the rotation radius of the blades of each of the stirring impellers may be different from the rotation radius of the blades of another stirring impeller.

Brief Description of Drawings

Fig. 1 is a longitudinal sectional view of a stirrer related to a first embodiment
Fig. 2 is a top view of a stirring impeller related to this embodiment.
Fig. 3 is a side view of the stirring impeller related to this embodiment.
Fig. 4 is a top view of a stirring impeller related to a second embodiment
Fig. 5 is a bottom view of the stirring impeller related to this embodiment.
Fig. 6 is an enlarged side view of a blade of the stirring impeller related to this embodiment.
Fig. 7 is a longitudinal sectional view of a stirrer related to another embodiment
Fig. 8 is a top view of a stirring impeller related to still another embodiment
Fig. 9 is a top view of a stirring impeller related to still another embodiment
Fig. 10 is an enlarged perspective view of blades of a stirring impeller related to still another embodiment uf
Fig. 11 is an enlarged perspective view of blades of a stirring impeller related to still another embodiment
Fig. 12 is a top view of a stirring impeller related to still another embodiment
Fig. 13 is a longitudinal sectional view of a stirrer related to still another embodiment
Fig. 14 is a top view of a stirring impeller related to this embodiment.
Fig. 15 is a longitudinal sectional view of a stirrer related to still another embodiment

Description of Embodiments

Hereinafter, a stirrer related to a first embodiment will be described with reference to Figs. 1 to 3. A stirrer 1 related to this embodiment is a vertical stirrer. The stirrer 1 includes a stirred tank 2 that contains an object to be stirred, a stirring shaft 3 that is rotatably attached within the stirred tank 2, a stirring impeller 4 that is attached to the stirring shaft 3, and a driving unit 5 that drives the stirring shaft 3. As the object to be stirred related to the present embodiment, a liquid L will be described as an example. However, the invention is not limited to this, and a high-viscosity object (for example, paste-like object), a mixture (for example, slurry) of a solid and a liquid, or the like is included in the object to be stirred.
The stirred tank 2 has a cylindrical shape that is long in a longitudinal direction. The stirred tank 2 includes a cylindrical body part 21, a bottom part 22 that is attached to a lower end of the body part 21 and is semi-elliptical in sectional shape, and a top part 23 that is attached to an upper end of the body part 21 and is semi-elliptical in sectional shape. The stirred tank 2 is held so that its axis center coincides with the vertical direction.
The stirring shaft 3 is arranged on the central axis of the stirred tank 2. The stirring shaft 3 has a lower end side supported via a bearing (not illustrated) provided at the bottom part 22 of the stirred tank 2. Moreover, the stirred tank 2 has an upper end side connected to the driving unit 5 (a motor in the present embodiment) provided above an upper part of the stirring shaft 3, and is configured so as to be rotatable in a circumferential direction A. In addition, the stirring shaft 3 may not have the lower end side supported anywhere. Additionally, the driving unit 5 may be provided below a lower part of the stirred tank 2, and the driving unit 5 may be connected to a lower end side of the stirring shaft 3.
The stirring impeller 4 includes a cylindrical boss 41 that is attachable to the stirring shaft 3, a plurality of support arms 42, ..., and 42 that protrude in a radial direction of the stirring shaft 3 from the boss 41, and blades 43 that are respectively attached to tip parts of the support arms 42. The boss 41, the respective support arms 42, and the respective blades 43 are fixed by welding, respectively. In addition, these may be fixed by means other than welding.
The boss 41 has a cylindrical shape, and has a through-hole 41a that is inserted through a lower end part of the stirring shaft 3. The stirring impeller 4 is attached to the stirring shaft 3 by the stirring impeller 4 being inserted through the through-hole 41a of the boss 41 and the boss 41 and the stirring shaft 3 being screw-fastened, welded, or the like.
Each support arm 42 is provided so as to protrude in the radial direction from an outer peripheral surface of the boss 41. The plurality of support arms 42, ..., and 42 are provided at equal intervals in a circumferential direction of the boss 41. Specifically, three support arms 42 are provided at intervals of 120 degrees in the circumferential direction of the boss 41 with the axis center of the stirring shaft 3 as a center. The shape of each support arm 42 is an elongated and tabular shape. The support arm 42 has a base end side (a stirring shaft 3 side) connected to the boss 41 and has a tip side (an inner surface side of the stirred tank 2) connected to the blade 43.
Additionally, the support arm 42 of the present embodiment is fixed to the boss 41 so that a plane that the support arm 42 has is orthogonal to the axial center direction of the stirring shaft 3. However, a side surface, an upper surface, or a lower surface of the support arm 42 that is formed in an elongated and tabular shape incline from a horizontal plane. In this case, when the support arm 42 is arranged so that a longitudinal direction thereof becomes a substantially horizontal direction within the stirred tank 2, a surface directed in the circumferential direction is a side surface of the support arm 42, a surface directed in an upward direction is an upper surface of the support arm 42, and a surface directed in a downward direction is a lower surface of the support arm 42. Accordingly, when the support arm 42 is extracted from the liquid L or a slurry as an object to be stirred that fills the inside of the stirred tank 2, the liquid L or the slurry is apt to hang down along the side surface, the upper surface, or the lower surface of the support arm 42, and the liquid L or the slurry does not easily remain on the surface of the support arm 42.
Each blade 43 is formed in a semi-cylindrical shape. The internal diameter of the blade 43 is formed with the same diameter from one end to the other end. Therefore, the width of the blade 43 is constant. The blade 43 has a blade body 44 to which the support arm 42 is attached, and a groove 45 that opens in a rotational direction B of the blade body 44. The blade body 44 is attached to the support arm 42 so that the groove 45 opens in the rotational direction B (a revolving direction B in which the blade 43 turns) . Additionally, the blade body 44 is attached to the support arm 42 at a substantially intermediate position in a cylinder core direction E that is a direction in which the center of the internal diameter of the blade 43 extends. The groove 45 extends in a direction (cylinder core direction E) orthogonal to the direction D passing through the rotation radius centered on the axis center of the stirring shaft 3. In the present embodiment, the groove 45 is formed in parallel along the axial center direction C of the stirring shaft 3. That is, the groove 45 is formed in the upward-downward direction. The groove 45 is formed by recessing a surface directed to the rotational direction B of the blade body 44, and is a groove that is formed in a semicircular shape in a sectional view. Therefore, the entire blade 43 is formed in a semicircular arc shape in a sectional view. The groove 45 is continuously formed from one end of the blade body 44 to the other end thereof in the cylinder core direction E. Therefore, both ends of the groove 45 in the cylinder core direction E open.
Next, the operation of the stirrer 1 related to the present embodiment will be described. First, if the driving unit 5 of the stirrer 1 is driven to rotate the stirring shaft 3, the stirring impeller 4 rotates within the stirred tank 2 around the stirring shaft 3, and shears the liquid L with the groove 45. The liquid L is received by the groove 45, and the liquid L is made to flow in the axial center direction C (upward-downward direction) along the groove 45. Specifically, the stirring impeller 4 makes the liquid L flow downward along the groove 45. As for the flow of the liquid L, the liquid turns outward at the bottom part of the stirred tank 2, turns upward on the side wall of the stirred tank 2, turns inward at the upper part of the stirred tank 2, and turns downward at a central part of the stirred tank 2, and returns to the position of the stirring impeller 4 again. The liquid L circulates within the stirred tank 2 in this way.
As described above, the stirrer 1 related to the present embodiment has the stirred tank 2 that contains the liquid L, the stirring shaft 3 rotatably attached within the stirred tank 2, and one or more stirring impellers 4 attached to the stirring shaft 3, the stirring impeller 4 has the plurality of blades 43, ..., and 43, each blade 43 has the blade body 44, and the groove 45 that opens in the rotational direction B, and the groove 45 is configured to extend in the direction E orthogonal to the direction D passing through the rotation radius centered on the axis center of the stirring shaft 3. Therefore, in the stirrer 1 related to the present embodiment, as the stirring shaft 3 is rotated, each blade 43 of the stirring impeller 4 rotates within the stirred tank 2 and shears the liquid L with the groove 45. Moreover, the rotating blade 43 of the stirring impeller 4 makes the liquid L received by the groove 45 flow in the axial center direction C of the stirring shaft 3 along the groove 45, and thereby also contributes to the circulation of the liquid L within the stirred tank 2. Hence, the stirring impeller 4 has excellent performance in both shear performance and circulation performance.
Additionally, in the stirrer 1 related to the present embodiment, the groove 45 is configured to be formed in a semicircular shape in a sectional view. Therefore, in the stirrer 1 related to the present embodiment, the groove 45 can make the liquid L flow in the axial center direction C of the stirring shaft 3 while bringing the liquid L closer to the center of the stirred tank 2, and can make it difficult for the liquid L to flow in the radial direction D of the stirring shaft 3. Additionally, the groove 45 raises the pressure applied to the liquid L by bringing the liquid L closer to the center of the groove 45 while making the liquid L flow to the axial center direction C of the stirring shaft 3, and when the liquid L flowing along the groove 45 is discharged from the groove 45, the pressure of the liquid L is released at a stretch (the pressure drops at a stretch), and thereby, the stirring reaction of the liquid L is promoted.
Additionally, in the stirrer 1 related to the present embodiment, the blade 43 is configured to be attached to the tip side of the support arm 42 and be attached to a position separated from the stirring shaft 3 in the radial direction D. Therefore, in the stirrer 1 related to the present embodiment, the shear surface when the stirring impeller 4 shears the liquid L is merely a portion of the area that is occupied in the radial direction D of the stirred tank 2. Therefore, the power that rotates the stirring shaft 3 in order to rotate the stirring impeller 4 is suppressed to be low.
Next, a stirrer related to the second embodiment will be described referring to Figs. 4 to 6. In addition, since the stirrer related to the present embodiment is different from the stirrer 1 related to the first embodiment in terms of the shape of a stirring impeller, and is basically the same as the stirrer 1 related to the first embodiment except for this, the same components will be designated by the same reference signs, and the description thereof will not be repeated.
The stirring impeller 4 related to the present embodiment has a blade 143 having a different shape from the blade 43 of the first embodiment. The blade 143 inclines at a predetermined angle α in the rotational direction B with respect to the axial center direction C of the stirring shaft 3 (refer to Fig. 6). Specifically, the blade 143 has a blade body 144 and a groove 145, similar to the first embodiment. The blade body 144 is attached to the support arm 42 at a substantially intermediate position of the cylinder core direction E, and is attached to the support arm 42 in a posture in which an upper end side of the stirring shaft 3 in the axial center direction C is inclined in a revolving direction F1 with the substantial intermediate position in the cylinder core direction E as a center (is rotated on the basis of the support arm 42) and a lower end side of the stirring shaft 3 in the axial center direction is inclined in a direction F2 reverse to the revolving direction F1 (rotated on the basis of the support arm 42) .
The direction in which the groove 145 extends inclines at a predetermined angle α in the rotational direction B with respect to the axial center direction C of the stirring shaft 3. It is preferable that the predetermined angle α of the groove 145 is an angle within a range of 45 degrees or less . In addition, although the groove 145 is inclined by inclining the blade 143 itself, the blade 143 itself may not incline, and only the groove 145 may incline. Additionally, the groove 145 opens obliquely downward in the rotational direction B. Hence, the groove 145 makes the liquid L flow obliquely downward with the rotation of the stirring impeller 4. The groove 145 is formed in a semicircular shape in a sectional view, and the blade 143 itself is formed in a circular arc shape in a sectional view. The shear area that the groove 145 shears is equivalent to the projected area as viewed from the direction F2 (a direction opposite to the rotational direction B of the stirring shaft 3) reverse to the revolving direction of the blade 143. In addition, the shear area may vary due to the circulatory flow of the liquid L within the stirred tank 2.
As described above, the stirrer 1 related to the present embodiment has a configuration in which the direction in which the groove 145 of the stirring impeller 4 extends inclines at a predetermined angle α in the rotational direction B with respect to the axial center direction C of the stirring shaft 3. Therefore, in the stirrer 1 related to the present embodiment, the liquid L received by the groove 145 flows along the direction of the groove 145 that inclines in the rotational direction B with respect to the axial center direction C of the stirring shaft 3. Therefore, the resistance applied to the groove 145 becomes low, and the circulation of the liquid L within the stirred tank 2 becomes apt to be caused.
As for the stirrer 1 related to the above embodiments, an example in which the number of blades 43 or 143 that constitute the stirring impeller 4 is three has been described. However, the invention is not limited to this. For example, the number of blades that constitute a stirring impeller attached to a stirring shaft may be two or may be four or more. Additionally, in a stirring shaft, two or four or more blades may be arranged at constant angles around the stirring shaft in a circumferential direction of the stirring shaft. That is, the respective blades may be provided so as to be separated at equal intervals in the circumferential direction of the stirring shaft.
Additionally, an assembly of a plurality of stirring impellers having a predetermined number of blades may be configured by combining a plurality of stirring impellers having one blade or a plurality of blades. Specifically, in a case where four blades are required for one stirring impeller, an assembly of stirring impellers having four blades may be formed by superimposing two stirring impellers having two blades.
As for the stirrer 1 related to the above embodiments, an example in which the blades 43 or 143 provided in the stirring impeller 4 are arranged at equal intervals in the circumferential direction of the stirring shaft 3 has been described. However, the invention is not limited to this. For example, the stirring impeller 4 may be provided with four blades that are arranged respectively at positions of 60 degrees, 120 degrees, 180 degrees, and 240 degrees around the stirring shaft 3 in the circumferential direction of the stirring shaft 3. That is, the respective blades may not be provided so as to be separated at substantially equal intervals in the circumferential direction of the stirring shaft.
Additionally, as illustrated in Fig. 7, the two stirring impellers 4 and 4 may be provided in two or more stages in the stirring shaft 3. That is, the stirring impellers 4 and 4 may be provided in two or more places so as to be separated at predetermined intervals in the axial center direction C of the stirring shaft 3. The positions of the two stirring impellers 4 and 4 in the axial center direction C of this stirring shaft 3 are arranged so as to be biased toward the lower end part or are arranged at equal intervals in the axial center direction C, depending on the properties of an object to be stirred that is a target to be stirred, the height (liquid level in a case where the object to be stirred is the liquid L) of the upper surface of the object to be stirred within the stirred tank 2, or the like. Therefore, the circulation performance of the object to be stirred within the stirred tank 2 in the axial center direction C of the stirring shaft 3 can be enhanced. Hence, the flow state of the liquid L within the stirred tank 2 improves. Additionally, it is also possible to cope with a high-capacity stirred tank 2 or a high-viscosity object to be stirred.
Additionally, as illustrated in Fig. 12, a plurality of the stirring impellers 4, ..., and 4 may be provided in the axial center direction of the stirring shaft 3, and each stirring impeller 4 may be attached to the stirring shaft 3 so that blades 143a to 143e of each stirring impeller 4 are arranged at positions shifted in the circumferential direction of the stirring shaft 3 from the positions of the blades 143a to 143e of another stirring impeller 4. Additionally, the blades 143a to 143e of each stirring impeller 4 may be arranged at positions shifted in the revolving direction (circumferential direction) B from the positions of the blades 143a to 143e of the other stirring impeller 4 in the revolving direction (circumferential direction) B of the stirring shaft 3. That is, the mutual positions (phases) of the blades 143a to 143e of the stirring impellers 4 may be positionally shifted in the axis center directional vision of the stirring shaft 3.
For example, the blade 143b of the stirring impeller 4 located in a second stage may be provided at a position rotated by 25 degrees in the revolving direction (circumferential direction) B of the stirring shaft 3 with respect to the position, in the circumferential direction B, of the blade 143a of the stirring impeller 4 located in a first stage that is the highest stage. The blade 143c of the stirring impeller 4 located in a third stage may be provided at a position rotated by 25 degrees in the revolving direction B of the stirring shaft 3 with respect to the position, in the circumferential direction B, of the blade 143b of the stirring impeller 4 located in a second stage. The same applies to the blades 143d and 143e of the stirring impellers 4 located in a fourth stage and a fifth stage. That is, the blades 143a to 143e of each stirring impeller 4 located in each stage may be arranged at spiral positions centered on the stirring shaft 3. In addition, the blades of each stirring impeller 4 may be spirally arranged.
Therefore, the blades 143a to 143e of each stirring impeller 4 can be arranged in accordance with the flow of the liquid L (object to be stirred) in the direction (upward-downward direction) of a stirring shaft within the stirred tank 2. Therefore, the flow of the liquid L in the direction of the stirring shaft can be smoothed, and the flow state of the liquid L within the stirred tank 2 improves.
In addition, an example in which the mutual blades 143a to 143e of the respective stirring impellers 4 are positionally shifted every 25 degrees in the revolving direction (circumferential direction) B of the stirring shaft 3 has been illustrated in Fig. 12. However, the invention is not limited to this. For example, the blades of the respective stirring impellers 4 may be positionally shifted every 90 degrees or may be positionally shifted at angles other than this. Additionally, the mutual blades of the respective stirring impellers 4 may not be positionally shifted in the circumferential direction.
Additionally, as illustrated in Figs. 13 and 14, a plurality of the stirring impellers 4, ..., and 4 may be provided in the axial center direction C of the stirring shaft 3, the grooves of the blades 143 of one stirring impeller 4 may incline at a predetermined angle in the rotational direction B with respect to the axial center direction C of the stirring shaft 3 on a rotation track of the stirring impeller 4, and the grooves of the blades 43 of another stirring impeller 4 may not incline in the rotational direction B with respect to the axial center direction C of the stirring shaft 3 on the rotation track of the stirring impeller 4. Particularly, it is preferable that the grooves of the stirring impeller 4 in an upper stage incline and the stirring impeller 4 in a lower stage does not incline. Moreover, in a case where three or more stages of stirring impellers 4 are provided, it is preferable that the stirring impeller 4 in the lowest stage does not incline. Accordingly, the stirring impeller 4 in an upper stage promotes the contamination of the liquid L, the stirring impeller 4 in a lower stage (or the lowest stage) promotes the discharge of the liquid L, and the flow state of the liquid L within the stirred tank 2 improves.
Additionally, as illustrated in Fig. 15, the rotation radius of the blades 43 of each stirring impeller 4 may be different from the rotation radius of the blades 43 of the other stirring impeller 4. Particularly, it is preferable that the rotation radius of the blades 43 becomes larger or becomes smaller from the stirring impeller 4 in an upper stage toward the stirring impeller 4 in a lower stage. Accordingly, the flow of the liquid L in the direction of the stirring shaft can be promoted by changing the rotation radius of the blades 43 of each stirring impeller 4 in accordance with the flow of the liquid L (object to be stirred) in the direction of the stirring shaft within the stirred tank 2.
As for the stirrer 1 related to the above embodiments, an example in which the blades 43 and 143 themselves have a semicircular arc shape (C-shape) in a sectional view and the grooves 45 and 145 have a semicircular shape in a sectional view has been described. However, the invention is not limited to this. For example, the grooves may have a semi-elliptical shape in a sectional view. Additionally, the blades themselves may have a circular arc shape with a central angle of 180 degrees or more in a sectional view or may have a circular arc shape with a central angle of 180 degrees or less in a sectional view. That is, the central angle is not limited to 180 degrees. The shape of the grooves may not be a curved surface, or may be a rectangular shape. For example, the grooves may have a triangular shape in a sectional view or may have a rectangular shape in a sectional view and a trapezoidal shape in a sectional view.
Additionally, the blades themselves may have a V-shape in a sectional view. More specifically, as illustrated in Fig. 8, a blade 243 having a V-shape in a sectional view may be formed by joining together ends of a pair of plate-shaped base materials 244 and 244 with almost the same length in a width direction in a v-shape. In this case, the groove may open in the rotational direction B, or may be directed in a direction closer to the radial direction D than the rotational direction B.
Additionally, as illustrated in Fig. 9, a blade 343 may be formed by joining together an end of a first base material 344 with a relatively short length in a width direction and an end of a second base material 345 with a relatively long length in the width direction in a V-shape. In this case, it is preferable that the first base material 344 is arranged on an outer side in the radial direction D and the second base material 345 is arranged on an inner side in the radial direction D. Since the length of the first base material 344 in the width direction is shorter than the length of the second base material 345 in the width direction, resistance in a tip part in the radial direction D is reduced. Therefore, compared to a case where the length of the second base material 345 in the width direction is the same as the length of the first base material 344 in the width direction, the number of rotations of the stirring impeller 4 can be made high at the same rotary torque. As the number of rotations becomes higher, the liquid L adhering to the stirring impeller 4 decreases.
Moreover, as illustrated in Fig. 10, a blade 443 may have a pair of through- holes 446 and 446 that pass through the front and back of the blade and allow an object to be stirred to escape to the back side. Specifically, the blade 443 has a blade body 444, a groove 445 that opens in the rotational direction B of the blade body 444, and the pair of through- holes 446 and 446 that are formed to pass through the blade body 444. Similar to the blade 243 illustrated in Fig. 8, the blade 444 is formed by joining together ends of the pair of plate-shaped base materials 447 and 447 with almost the same length in the width direction G in a V-shape, and the pair of through- holes 446 and 446 are formed by forming gaps between the pair of base materials 447 and 447. The shape of the pair of through- holes 446 and 446 is a rectangular slit, and is provided in a cylinder core direction H from both end sides of the blade body 444 in the cylinder core direction H (longitudinal direction). In addition, as for the pair of through- holes 446 and 446, as illustrated in Fig. 11, a pair of through- holes 546 and 546 that pass through the front and back of a blade 543 having a blade body 544 obtained by joining together a pair of base materials 547 and 547 with different lengths in the width direction in a V-shape, and a groove 545 and that allows an object to be stirred to escape to the back side may be formed, or may be provided in blades having other sectional blades, such as a blade having a semicircular arc shape in a sectional view. Additionally, the shape of the pair of through- holes 446 and 446 may be a circular shape or elliptical in addition to the rectangular slit, and the number of through-holes 446 may be one or may be three or more. The positions of the pair of through- holes 446 and 446 are not limited to both end sides of the blade body 444 in the cylinder core direction H, and may be intermediate positions in the cylinder core direction H.
Additionally, as for the stirrer 1 related to the above embodiments, an example in which the blades 43 and 143 themselves have a semicircular arc shape (C-shape) in a sectional view has been described. However, the invention is not limited to this. For example, the shape of the blades may be a rectangular shape (concave shape) in a sectional view. Additionally, the width of the grooves may become narrow from one end side in the longitudinal direction toward the other end side opposite to the one end side. Even if such a configuration is adopted, the pressure applied to an object to be stirred can be raised by bringing the object to be stirred closer to the centers of the grooves, and when the object to be stirred flowing along the grooves is discharged from the grooves, the pressure of the object to be stirred is released at a stretch (the pressure drops at a stretch), and thereby, the stirring reaction of the object to be stirred is promoted.
As illustrated in Fig. 6, as for the stirrer 1 related to the above embodiments, an example in which the blade 143 is attached to the support arm 42 in a posture in which the upper end side of the stirring shaft 3 in the axial center direction C is inclined in the revolving direction F1 with the substantially intermediate position in the cylinder core direction E as a center and the lower end side of the stirring shaft 3 in the axial center direction C is inclined to the side F2 opposite to the revolving direction has been described. However, the invention is not limited to this. For example, an example in which the blade 143 is attached to the support arm 42 in a posture in which the lower end side of the stirring shaft 3 in the axial center direction C is inclined in the revolving direction F1 with the substantially intermediate position in the cylinder core direction E as a center and the upper end side of the stirring shaft 3 in the axial center direction C is inclined to the side F2 opposite to the revolving direction has been described. However, the invention is not limited to this. In this case, a circulatory flow reverse to a circulatory flow of the object to be stirred of the stirrer 1 related to the above second embodiment can be obtained.
As for the stirrer 1 related to the above embodiments, an example in which the support arm 42 and the blade 43 or 143 are fixed together by welding has been described. However, the invention is not limited to this. For example, the support arm and the blade may be attached to each other by being bolt-fastened.
As for the stirrer 1 related to the above embodiments, an example in which the length of the blade 43 or 143 in the cylinder core direction E is longer than the length of the blade 43 or 143 in the width direction (or the length of the groove 45 or 145 in the longitudinal direction is longer than the length of the groove 45 or 145 in the width direction) has been described. However, the invention is not limited to this. For example, as for the shape of the blade, the length of the blade in the cylinder core direction or the length of the groove in the longitudinal direction may be shorter than the length of the blade or the groove in the width direction.
As for the stirrer 1 related to the above embodiments, an example in which the stirring shaft 3 and the blade 43 revolve in the counterclockwise direction with respect to the rotational direction B as viewed from above has been described. The invention is not limited to this. For example, the stirring shaft 3 and the blade 43 may revolve in the clockwise direction. In this case, a circulatory flow reverse to a circulatory flow of the object to be stirred of the stirrer 1 related to the above first and second embodiments can be obtained.
As for the stirrer 1 related to the above embodiments, an example in which the blade 43 is connected to the boss 41 via the support arm 42 has been described.
As for the stirrer 1 related to the above embodiments, an example in which the groove 45 or 145 extends in the direction E orthogonal to the direction D passing through the rotation radius centered on the axis center of the stirring shaft 3 has been described. However, the invention is not limited to this. For example, the blade may be connected to the support arm so that the groove extends in the direction orthogonal to the direction D passing through the rotation radius centered on the axis center of the stirring shaft 3. For example, the upper part of the blade 43 illustrated in Fig. 3 may incline to the outer side in the radial direction D, and the lower part of the blade 43 may incline to the inner side in the radial direction D inner side, and vice versa.
As for the stirrer 1 related to the above embodiments, an example in which the stirred tank 2 that has a semi-elliptical bottom part 22 and a semi-elliptical top part 23 obtained by welding semi-elliptical end plates to both ends of a cylindrical shell plate has been described. However, the invention is not limited to this. For example, the bottom part and the top part of the stirred tank may be portions obtained by welding end plates of other shapes to a shell plate. Examples of other end plates other than the semi-elliptical end plate used for the bottom part include end plates of a dish type having a 10% dish shape or the like, a semi-spherical type having a semi-spherical shape, a flat type having a flat shape, a conical type having a conical shape or a truncated conical shape, and the like. Additionally, examples of other end plates other than the semi-elliptical end plate used for the top part include end plates of a dish type having a 10% dish shape or the like, a semi-spherical type having a semi-spherical shape, a flat type having a flat shape, and the like.

Reference Signs List

1: STIRRER
2: STIRRED TANK
21: BODY PART
22: BOTTOM PART
23: TOP PART
3: STIRRING SHAFT
4: STIRRING IMPELLER
41: BOSS
41a: THROUGH-HOLE
42: SUPPORT ARM
43: BLADE
44: BLADE BODY
45: GROOVE
5: DRIVING UNIT
143, 143a, 143b, 143c, 143d, 143e: BLADE
144: BLADE BODY
145: GROOVE
243: BLADE
244: BASE MATERIAL
343: BLADE
344: FIRST BASE MATERIAL
345: SECOND BASE MATERIAL
443: BLADE
444: BLADE BODY
445: GROOVE
446: THROUGH-HOLE
447: BASE MATERIAL
543: BLADE
544: BLADE BODY
545: GROOVE
547: BASE MATERIAL
α: INCLINATION ANGLE
L: LIQUID (OBJECT TO BE STIRRED)
A: CIRCUMFERENTIAL DIRECTION
B: ROTATIONAL DIRECTION (REVOLVING DIRECTION)
C: AXIAL CENTER DIRECTION
D: DIRECTION (RADIAL DIRECTION) PASSING THROUGH ROTATION RADIUS CENTERED ON AXIS CENTER OF STIRRING SHAFT
E: DIRECTION (CYLINDER CORE DIRECTION) ORTHOGONAL TO DIRECTION PASSING THROUGH ROTATION RADIUS CENTERED ON AXIS CENTER OF STIRRING SHAFT
F1: ROTATIONAL DIRECTION
F2: DIRECTION REVERSE TO REVOLVING DIRECTION
G: WIDTH DIRECTION
H: CYLINDER CORE DIRECTION

Claims

A vertical stirrer (1) comprising:
a stirred tank (2) configured to contain an object (L) to be stirred;

a stirring shaft (3) rotatably attached within the stirred tank (2); and

at least one stirring impeller (4) attached to the stirring shaft (3),

wherein the at least one stirring impeller (4) each have a plurality of blades (143; 243; 343; 443; 543) that are attached respectively to tip parts of a plurality of support arms (42),

wherein a cylindrical boss (41) is attached to the stirring shaft (3), the plurality of support arms (42) protruding in a radial direction of the stirring shaft (3) from the boss (41), the support arms (42) being fixed to the boss (41)

wherein the blades (243; 343; 443; 543) each have a blade body (244; 344; 444; 544) and a groove (45; 145; 445; 545) that opens in a rotational direction (B), and

wherein the groove (45; 145; 445; 545) extends in a direction (E) intersecting a direction (D) passing through a rotation radius centered on an axial center of the stirring shaft (3)
characterized in
that each of the plurality of support arms (42) is in an elongated and tabular shape and
that any one of a side surface, an upper surface, and a lower surface of the support arms (42) inclines from a horizontal plane
The stirrer (1) according to Claim 1,
wherein the direction in which the groove (45; 145; 445; 545) extends inclines at a predetermined angle (α) in the rotational direction (B) with respect to the axial center direction (C) of the stirring shaft (3).
The stirrer (1) according to Claim 1 or 2,
wherein the groove (45; 145; 445; 545) is formed in a semicircular shape in a sectional view.
The stirrer (1) according to any one of Claims 1 to 3,
wherein the stirring impellers (4) are provided in two or more stages in the stirring shaft (3).
The stirrer (1) according to Claim 4,
wherein each of the stirring impellers (4) is attached to the stirring shaft (3) so that the blades (143a-143e) of each of the stirring impellers (4) are arranged at positions shifted in the circumferential direction (B) of the stirring shaft (3) from the positions of the blades (143a-143e) of another stirring impeller (4).