JPS6150006B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a rotary-blade type agitator, and particularly to a rotary-blade type agitator capable of efficiently kneading and kneading materials with low fluidity such as highly viscous liquids, sludge, and granular materials. Conventionally, a large number of rotary blade stirrers have been proposed for stirring and uniformly mixing liquids or powders in tanks such as storage tanks, mixing tanks, reaction tanks, etc., and some of them have been put into practical use. It is provided. In particular, with the intention of evenly stirring materials to be stirred with low fluidity such as highly viscous liquids, sludge, or granules, and kneading them in a short time, the stirring blades are rotated and moved up and down. A mechanism has been proposed in which the rotational speed of the stirring blade can be selected to a desired value in accordance with the viscosity of the substance to be stirred, in accordance with the viscosity of the substance to be stirred. (Japanese Patent Publication No. 49-46350) This type of stirrer is not practical due to problems in the structure of its stirring blades, problems in setting the speed ratio between the rotational movement and vertical movement of the stirring blades, and various other factors. When the machine is operated, the mixing resistance of the materials to be stirred becomes large, and excessive power load resistance occurs, so a powerful driving source is required, and the machine itself becomes extremely unstable, resulting in poor operability. In order to eliminate this drawback, Japanese Patent Publication No. 52-2141 proposes that a circular arc based on a fan-shaped angle be placed on a support member horizontally fixed to the lower end of the rotary lifting shaft, within a required radius from the shaft, and at a position outside the shaft. An appropriate number of first and second blades formed in a shape are arranged with respective inclination angles corresponding to the flow curve related to the spiral motion of the stirring blade, and the first blade at each radial position is The inclinations of the first blade and the second blade are both in the same direction with respect to the rotation direction.
In the second wing, cross each other in different directions,
Then, an agitator was devised in which the slope of the second outer blade was set appropriately smaller than the first inner blade, and an attempt was made to reduce the size of the power and improve operability and efficiency. It was done. However, all of these conventionally known stirrers
Although it has certain advantages, it still has the disadvantage that it has not yet solved the following serious problems. In other words, the substance to be stirred is a reactive high-viscosity substance that generates or absorbs heat of reaction, or a substance that causes a significant change in the viscosity range over time (for example, a change from a low viscosity range to a high viscosity range, or vice versa). In particular, if the material exhibits adhesion to the wall surface, or if the flow resistance against the tank wall increases due to transfer of reaction heat (flow deteriorates on the wall), Although the fluid state of the water is maintained for the time being, the material to be stirred between the tank wall and the tip of the stirring blade near it is not efficiently replaced with the material to be stirred located inward, and the material to be stirred is kept along the tank wall. This forms a so-called moving layer that continues to move only in the circumferential direction. As a result, not only do mixture spots occur between the vicinity of the tank wall and the inner part of the tank, but also, especially in the case of highly viscous substances whose viscosity changes over time as the reaction progresses, the above-mentioned The moving layer lowers the overall heat transfer coefficient on the tank wall surface, thus deteriorating the heat exchange efficiency through the tank wall, and in severe cases, the moving layer turns into a stop layer or a solidified layer, preventing uniform mixing. Of course, it becomes virtually impossible to exchange heat. The present invention was completed as a result of intensive research in order to solve the various problems associated with the conventionally known rotary blade type agitators as described above, as well as the technical problems that cannot be solved by these devices. The purpose of this is to transfer reactive high viscosity substances that generate or absorb reaction heat or substances whose viscosity range changes significantly over time to the walls of a mixing tank or reaction tank. It is an object of the present invention to provide a rotary blade type agitator suitable for uniformly mixing and mixing throughout the tank in a relatively short time without reducing thermal efficiency. That is, the rotary blade type agitator according to the present invention has a vertical main shaft that is arranged concentrically in a vertical cylindrical tank and that can simultaneously perform rotational movement around the axis and vertical reciprocating movement in the direction of the axis, and the main shaft. A highly viscous liquid consisting of multiple stirring blades supported from the lower end toward the tank wall.
In a rotary blade agitator for kneading mud or powder or granules, a plurality of inner blades that are appropriately spaced apart from the inner wall of the tank and equally inclined in the same direction with respect to the horizontal plane, and a plurality of inner blades that are close to the inner wall are provided. Alternatively, a plurality of outer blades that are in sliding contact and tilted equally in the opposite direction to the inclination direction of the inner blade are configured and arranged in shapes and related positions that have integral-order rotational symmetry around the center line of the main axis, respectively,
The width of each wing is determined so that the inclination angle α of the inner wing with respect to the horizontal plane is smaller than the inclination angle β of the outer wing, and the maximum projected height of the inner wing with respect to the vertical plane does not exceed the maximum projected length cd of the outer wing. The present invention is further characterized in that at least the outer edge portion of the outer wing is appropriately inclined in the direction of forward motion of the wing as the main shaft rotates. The invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is an elevational view showing a rotating four-blade agitator attached to a vertical cylindrical tank, and FIG. 2 is a plan view thereof. In the figure, the vertical main shaft 2 of the stirrer is inserted vertically into the cylindrical tank 1 so that its axis coincides with the central axis of the cylindrical tank 1, so that the stirrer and the cylindrical tank 1 are are in a concentric relational arrangement. This vertical main shaft 2 is equipped with a known appropriate mechanism, for example, as disclosed in Japanese Patent Publication No. 49-46350, so that it can rotate around its axis and move up and down in the direction of its axis at the same time. Connected to a driving source. At the lower end of the vertical main shaft 2, there are a plurality of stirring blades 3,
3'..., 4, 4'... extend in the direction of the tank wall, that is, in the normal direction, and are convergent and supported. These stirring blades consist of a rod-shaped support member 5 whose one end is fixed to the lower end portion of the vertical main shaft 2, and an effective working part of a flat plate or dish-shaped body attached to the other end. can also be integrally molded. The effective working part of such a stirring blade is located at the inner edge 3, 3' located near the approximate center of the radius of the cylindrical tank 1.
. . . and a group of outer wings 4, 4', located along the tank wall and sufficiently close to the tank wall. The inner blades 3, 3'... and the outer walls 4, 4'... are each constructed and arranged in a shape and relational arrangement that exhibits rotational symmetry of an integer order around the axis of the vertical main shaft 2, that is, the center line in the longitudinal direction. It must be. That is, the first
The example shown in the figure and FIG. 2 is a case where the shape completely matches the initial position at every rotation angle of 4π/2, that is, the case has rotational symmetry of degree n=2, and FIG. This is an example where the degree n of rotational symmetry is 3.
It is possible to further increase the order of rotational symmetry, but this means an increase in the number of stirring blades, a large capacity ratio of the drive source due to an increase in stirring resistance, securing mechanical strength, etc. However, it cannot necessarily be said that it is a good idea, and 2 to 4 is a preferable range. FIG. 4 is a plan view showing another preferred example of the stirrer of the present invention. In this example, the inner wing 3,
3' and the outer wings 4, 4' are mounted on a common support member 5, 5' which is structurally fixed to the lower end portion of the vertical main shaft 2. In this case, the degree n of rotational symmetry is set to ⁴ by further providing orthogonal support members,
Stirring efficiency can be increased without unduly complicating the device. In the above-mentioned examples, the supporting members of the stirring blades are all mounted on the same plane, but it goes without saying that they can be arranged in multiple stages above and below as long as rotational symmetry is satisfied. FIG. 5 is an explanatory diagram showing the relationship between the width and the inclination angle of the stirring blade of the apparatus of the present invention. In the figure, the inner wing 3 and the outer wing 4 move along spiral trajectories as a result of the rotational movement and vertical reciprocating movement of the vertical main shaft (not shown), respectively, but the direction of movement due to only the rotational movement is limited. I assumed it and pointed it out. At this time, the inner wing 3 is tilted upward in the moving direction with respect to the horizontal plane X-X at an appropriate angle α.
, and the outer wings 4 are tilted at an opposite angle β. Contrary to the above, the direction of inclination may be such that the inner wing 3 is in the prone direction and the outer wing 4 is in the up-and-down direction, but in either case, it is important to maintain the angular relationship of the internal angle of α<β. . Further, the width of each blade, that is, the maximum width of the effective working portion of the stirring blade (maximum length in the direction orthogonal to the support member) must be appropriately determined in relation to the inclination angle of the blade. In Fig. 5, if the projected length of the maximum width of the inner blade 3 and the projected length of the maximum width of the outer blade 4 with respect to the vertical plane Y-Y are taken as the projected length, in order to obtain the best stirring effect, The relationship AB≧CD, that is, the formula,

The inventors have confirmed through numerous experiments that it is necessary to set the dimensions of each wing span so as to satisfy the following. In this way, both the inclination angle β and the maximum width of the effective working portion of the outer wing 4 are closely related to those values of the inner wing 3, and the preferred ranges of these values are as follows. πr ₁ /4n≦≦πr ₁ /n (2) However, n is the order of rotational symmetry, and r ₁ is the distance between the center of the maximum width of the inner wing 3 and the axis of the vertical main shaft 2. If the value of r ₁ is relatively large within the range that satisfies equation (2), then select small, and if r ₁ is relatively small, select large. If the deviation from the range of formula (2) is too small, the stirring efficiency will drop significantly, and if it is too large, the stirring resistance will become excessive and the mechanical load will increase significantly, which is not appropriate. Furthermore, the inclination angle α of the inner wing 3 is determined according to the spiral locus in which the wing advances, that is, the ratio of the rotational speed of the vertical main shaft 2 to the vertical reciprocating speed, so that the axis in the width direction of the wing matches parallel to the helical trajectory. It is preferable to set these relationships appropriately to avoid
It is designed in the range of 85°, more preferably in the range of 10° to 60°, and most preferably in the range of 15° to 45°. Similarly, it goes without saying that the inclination angle β of the outer wing 4 is determined so that the spiral locus and the axis in the width direction of the wing are not parallel to each other. FIG. 6 is an explanatory diagram showing the distance of the effective working portion of each blade from the vertical main axis. In the figure, inner wing 3
The distance between the center P of the maximum width of and the axis O of the vertical main axis 2
It is desirable to determine the value of r ₁ so that the effective working part of the blade falls within the range of approximately 0.1 to 0.7 of the inner radius R of the cylindrical tank 1, and the outer edge shape is centered around the axis O. It is most appropriate to form it so that it includes a portion along an arc drawn with r ₁ as the radius. Also, the value of the distance r ₂ between the maximum width center Q of the outer wing 4 and the axis O is:
It is best to set the effective working part of the blade to be in the range of 0.7R to 1.0R, and furthermore, the outer edge should be sufficiently close to the tank wall with a small gap of several millimeters, or It must be in sliding contact with the tank wall.
Therefore, the outer edge shape is formed to include a curve along the long axis of an ellipse formed by cutting the cylindrical tank 1 at a plane that includes the outer blades 4, that is, a plane that is inclined at an angle β with the horizontal plane. However, consideration should be given to maintaining a uniform gap between them and the tank wall, or to allow smooth sliding contact with the tank wall. FIG. 7 shows that when the outer blade 4 comes into sliding contact with the tank wall surface, the outer edge of the blade in contact with the tank wall is formed with a buffer member 6 made of an elastic organic material, and the present invention can be used without damaging the tank wall. It shows an embodiment that can effectively achieve the objective. Next, FIGS. 8A and 8B are a plan view and a sectional view taken along the line E--E, respectively, showing the shape of the outer wing 4 of the device of the present invention. The arrow in FIG. 8B indicates the advancing direction of the outer wing 4, and the outer edge end portion of the wing must be inclined forward at an appropriate angle θ with the center line of the support member 5. In this example, a part of the outer wing 4 is curved and inclined, but the entire wing may be fixed to the supporting member at an angle, and an appropriate value of the angle θ is 10° to 10°.
90°, preferably within the range of 15° to 75°. In the above explanation, the shape of the effective working part of the stirring blade is mainly exemplified as a paddle shape surrounded by a curved line, but it is not limited to this, and may be, for example, a fan shape as shown in FIG. 7, or other suitable modifications. is possible. However, it is desirable that the areas of the effective working portions of the inner wing 3 and the outer wing 4 are set to be approximately equal to each other. The functions and effects of the rotary blade agitator according to the present invention explained in detail above will be described below. As the vertical main shaft 2 rotates around the axis O and reciprocates up and down, the rotational movement and up and down movement of the stirring blades are combined to form a helical locus, and both the inner blades 3 and the outer blades 4 move along the helical locus. It seems that it does not match in parallel with
Since it is inclined at an appropriate angle, the materials to be stirred in the tank can be stirred and mixed very efficiently. In other words, if we take the case where the inner blade 3 is tilted upward in the direction of movement, the material to be stirred near the center of the cylindrical tank will be pushed down diagonally and at the same time, the flow will tend to move in the centrifugal direction. The material to be stirred near the tank wall is pushed upward diagonally by the movement of the outer blades 4, and also moves in the centripetal direction due to the inclination of the outer edge of the outer blades 4 in the forward direction. Because they occur simultaneously, it facilitates the exchange of the inner and outer layers as well as the upper and lower layers of the material to be stirred, creating an extremely complicated fluid state.
Actions such as stirring, mixing, mixing, etc. can be performed uniformly over the entire tank within a short period of time. In addition, in particular, the width of the outer blade 4 is set to an appropriate size based on the width of the inner blade 3, so that even though the linear velocity of the outer blade 4 is high, excessive stirring resistance is not generated, and the device can be easily operated. It is possible to make the outer blade relatively compact, and the passing width of the outer blade on the tank wall surface is quite large, and the edge of the outer blade is formed in an elliptical curve based on the curve of the tank wall surface. The fact that the agitator is brought sufficiently close to or in sliding contact with the tank wall surface, together with the forced movement of the material to be stirred in the centripetal direction of the tank wall surface due to the forward inclination of the outer blade edge portion in the direction of movement as described above, There is a remarkable synergistic effect in that the materials to be stirred on the wall are updated very smoothly. Therefore, when applied to stirring highly viscous substances or substances that adhere to walls, especially reactive substances that require transfer of reaction heat through the tank walls, the fluid mixing state in the tank can be maintained without any corner. While maintaining the so-called mobile layer,
Since no solidified layer or the like is formed on the wall surface, the efficiency of reaction heat exchange can be significantly improved without reducing the overall heat transfer coefficient of the tank wall. In the above description, a specific example of the stirrer of the present invention is described as one in which a plurality of stirring blades are arranged on the same plane.
However, depending on the inner diameter and height of the cylindrical tank, the pitch of the spiral trajectory of the stirring blades, etc., the number of stirring blades can be adjusted as appropriate to maintain a rotationally symmetrical arrangement. If the amount is increased within the above-mentioned range, the above-mentioned stirring action can be effected in all stages, and excellent effects can be achieved. Furthermore, the device of the present invention has the advantage of having a simple structure and being able to be miniaturized, being easy to clean, assemble, etc., and saving power. The effects of experiments in which the device of the present invention was actually applied will be described below. Example A rotary blade type stirrer as shown in FIGS. 1 and 2 was attached to a vertical cylindrical tank with an inner diameter of 300 mm, a height of 500 mm, and a capacity of 30 with a jacket. The specifications of the wing were set as follows. α = 15° β = 75° r ₁ = 100 mm r ₂ = 148 mm = 90 mm = 70 mm θ = 15° In addition, the number of rotations of the vertical spindle was 60 r.pm, the stroke of the vertical reciprocating movement was 90 mm, and the number of reciprocations was 54 times/min. When a crystallization reaction of edible oil and fat with a viscosity of 70 cps was carried out under these conditions, as shown in Figure 9, even though heat of crystallization reaction was generated during the cooling process, the temperature could be efficiently cooled to the set temperature (jacket temperature). was completed, and the crystallization reaction progressed effectively as seen from the change in viscosity over time. Comparative example Using the same cylindrical tank as in the above example,
A crystallization reaction was carried out on the same lot of edible oils and fats as described above under the same cooling conditions as in the example using the known stirring blade disclosed in Publication No. 2141, but as shown in Figure 10, during the cooling process From the stage where crystals were formed, a stagnant layer was formed on the tank wall, which transitioned to a solidified layer with the passage of time. As a result, the overall heat transfer coefficient at the tank wall decreased, and crystallization heat accumulated in the tank, making it impossible to carry out the crystallization reaction.

[Brief explanation of the drawing]

FIG. 1 is an elevational view showing one example of the agitator of the present invention;
FIG. 2 is a plan view thereof, FIGS. 3 and 4 are plan views showing another aspect of the present invention, and FIGS. 5 and 6 are explanatory views showing the shape and arrangement of stirring blades according to the present invention. , FIG. 7 is a plan view showing an embodiment of the outer wing according to the present invention, FIG. 8A is a plan view similarly showing the shape of the outer wing, FIG. 8B is a sectional view taken along the line E-E, and FIG. is a diagram showing the action and effect of the device of the present invention, 1st
Figure 0 is a comparison chart showing the performance of conventionally known stirrers. DESCRIPTION OF SYMBOLS 1... Vertical cylindrical tank, 2... Vertical main shaft, 3... Inner wing, 4... Outer wing, 5... Support member, 6... Buffer member.

Claims (1)

[Scope of Claims] 1. A vertical main shaft that is arranged concentrically in a vertical cylindrical tank and that can simultaneously rotate around the axis and perform vertical and downward reciprocating movements in the direction of the axis, and a vertical main shaft that is arranged from the lower end of the main shaft. In a rotary blade stirrer for kneading highly viscous liquids, slurry, granules, etc., which consists of a plurality of stirring blades supported in the direction of the tank wall, a horizontal surface is appropriately spaced from the inner wall of the tank. A plurality of inner wings that are equally inclined in the same direction relative to the inner wall, and a plurality of outer wings that are close to or in sliding contact with the inner wall and are equally inclined in the opposite direction to the inclination direction of the inner wings, respectively around the center line of the main axis. The inner wing is constructed and arranged in a shape and in a related position that has rotational symmetry of an integer order, and the inclination angle α of the inner wing with respect to the horizontal plane is
is smaller than the inclination angle β of the outer wing, and the width of each wing is determined so that the maximum projected height of the inner wing with respect to the vertical plane does not exceed the maximum projected length cd of the outer wing, and at least the outer wing of the outer wing is A rotary blade agitator characterized in that an edge portion is appropriately inclined in the forward direction of the blades as the main shaft rotates. 2. The rotary blade stirrer according to claim 1, wherein the order of rotational symmetry is 2 to 4. 3. The rotary blade agitator according to claim 2, wherein the inner blade and the outer blade are provided on a common support member. 4. The rotary blade stirrer according to claim 1, which satisfies the relationship sinα≦sinβ and≧, where the maximum width of the outer blade is taken as the maximum width of the outer blade. 5. The rotary vane type agitator according to claim 2, wherein the inner blade has an effective working portion with a maximum width that satisfies the following formula. πr ₁ /4n≦≦πr ₁ /n where n is the order of rotational symmetry, and r ₁ is the distance between the center of the maximum width of the inner wing and the axis of the vertical main axis. 6 The inclination angle α of the inner wing and the inclination angle β of the outer wing are
The rotary vane type agitator according to claim 1, wherein the spiral trajectory of the blades is determined so that the axis in the width direction of each blade is not parallel to each other. 7. The rotary blade stirrer according to claim 6, wherein the value of α is 5° to 85°. 8. The rotary blade stirrer according to claim 6, wherein the value of α is 10° to 60°. 9. The rotary blade stirrer according to claim 6, wherein the value of α is 15° to 45°. 10. The rotary vane type agitator according to claim 5, wherein the value of 10 r ₁ is determined so that the effective working portion of the inner vane is within the range of 0.1 to 0.7 of the inner radius of the cylindrical tank. 11. The rotary vane type agitator according to claim 10, wherein the inner blade is formed in an outer edge shape including an arc portion whose radius is r ₁ centered on the axis of the vertical main shaft. 12. The rotor blade according to claim 10, wherein when the inner radius of the cylindrical tank is R, the effective working part of the outer blade is located outside a circle drawn around the axis with a radius of 0.7R. type stirrer. 13. Claim 1, wherein the outer wing is formed in an outer edge shape including a curve along the long axis of an ellipse formed by the intersection of the cylindrical tank and the plane containing the outer wing.
The rotary blade stirrer according to item 2. 14. The rotary blade agitator according to claim 13, wherein the outer edge portion of the outer blade is formed with a buffer member made of an elastic organic material. 15. The rotary blade agitator according to claim 1, wherein at least the outer edge portion of the outer blade is inclined by 10° to 90° in the forward movement direction of the blade as the main shaft rotates. 16. The rotary blade agitator according to claim 1, wherein at least the outer edge portion of the outer blade is inclined by 15° to 75° in the forward movement direction of the blade as the main shaft rotates. 17. Claim 1 wherein the inner wing and the outer wing have effective working portions of approximately equal area to each other.
Rotary vane type agitator as described in section.