JP4580585B2 - Control method of external circulation amount of external circulation type agitator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control method for external circulation of external circulation type stirring equipment. More specifically, external circulation type agitation of a structure in which liquids such as various fluids and semi-fluids are agitated in the tank, led out of the tank, subjected to various liquid treatments, and returned to the tank for circulation. a control method for controlling an external circulation amount of equipment.
[0002]
[Prior art]
FIG. 3 shows a conventional external circulation type stirring device 100. As shown in the figure, in the conventional external circulation type stirring device 100, a rotating shaft 111 having a stirring blade 112 is provided in a stirring tank 110 that contains a fluid, and by rotating the rotating shaft 111, The stirring blade 112 performs stirring and uniform mixing of the fluid in the stirring tank 110.
In the external circulation type stirring device 100, an external pipe 113 is provided for communicating between the side surface and the lower end of the stirring tank 110, and the pump P provided in the middle of the external pipe 113 is used in the stirring tank 110. The fluid is circulated through the external pipe 113. The external pipe 113 is provided with processing measures 114 for heating the fluid and performing various chemical processes during the stirring operation.
For this reason, if the fluid in the stirring tank 110 is introduced into the external pipe 113 by the pump P while stirring the fluid in the stirring tank 110 by the stirring blade 112, the fluid flowing in the external pipe 113 can be heated, Or chemical treatment.
[0003]
[Problems to be solved by the invention]
However, in the conventional external circulation type agitator 100, since the fluid is mechanically circulated externally, the flow of the fluid that passes through the external pipe 113 regardless of the flow state in the agitation tank 110, that is, the rotation speed of the agitation blade 112 is determined. Although the flow rate can be controlled, there is a problem that a system for controlling the operation of the pump P becomes complicated, and maintenance and running costs of the pump P are required.
In order to solve the above problem, an agitator that circulates the fluid externally using the pressure distribution in the fluid agitation tank 110 without using the pump P as a power source for supplying the fluid to the external pipe 113 may be considered. However, in this case, there is a problem that the flow rate of the fluid passing through the external pipe 113 and the flow in the stirring tank 110 cannot be controlled simultaneously.
[0004]
In view of such circumstances, the present invention can externally circulate the fluid in the agitation tank without using a mechanical power source such as a pump, and simultaneously adjusts the external circulation amount and the flow state in the agitation tank. and to provide a control method for external circulation of external circulation type stirring equipment that can be.
[0005]
[Means for Solving the Problems]
The method for controlling the amount of external circulation of the external circulation type stirring device according to claim 1 comprises: a stirring tank for containing a fluid; a rotary shaft provided vertically and rotatably in the stirring tank; and attached to the rotary shaft In the external circulation type agitation device comprising an agitating blade for agitating the fluid contained in the agitation tank, and an external pipe communicating between the side surface and the bottom surface outside the agitation tank, A control method for controlling a flow rate of a fluid flowing in an external pipe, wherein a baffle is provided in the agitation tank so as to intersect a turning direction in a horizontal plane of the fluid in the agitation tank. By extending or contracting the length, the flow rate of the fluid flowing in the external pipe is increased or decreased .
[0006]
According to the first aspect of the present invention, the flow rate of the fluid flowing in the external pipe can be changed by changing the rotational speed of the rotary shaft. In addition, if the length of the baffle is increased, resistance to swirling of the fluid centering on the rotating shaft increases, so that the vertical circulation of the fluid in the stirring tank can be strengthened, and the fluid flowing in the external piping The flow rate can be reduced. On the contrary, if the length of the baffle is shortened, resistance to swirling of the fluid around the rotation axis is reduced, so that the vertical circulation in the stirring tank can be weakened, and the fluid flowing in the external pipe can be reduced. The flow rate can be increased. Therefore, if the number of rotations of the rotating shaft and the length of the baffle are adjusted, the flow rate of the fluid flowing in the external pipe and the flow state of the fluid in the stirring tank can be adjusted simultaneously .
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic longitudinal sectional view of an external circulation type stirring device 1 of the present embodiment. As shown in the figure, the external circulation type stirring device 1 of this embodiment is basically composed of a stirring tank 10, a rotating shaft 11, a stirring blade 12 and an external pipe 13, and a baffle 20 is provided in the stirring tank 10. The rotation speed of the rotating shaft 11 and the baffle 20 are characterized in that the flow rate of the fluid L flowing in the external pipe 13 and the flow state in the stirring tank 10 can be adjusted.
[0008]
The agitation tank 10 is a hollow cylindrical container for containing a fluid L such as a liquid material or a semi-liquid material such as a liquid slurry or a polymer water slurry.
A rotating shaft 11 that is vertical and concentric with the central axis of the stirring tank 10 is provided inside the stirring tank 10. The rotating shaft 11 is rotatably attached to the stirring tank 10. A stirring blade 12 is attached to the lower end of the rotating shaft 11.
For this reason, if the rotating shaft 11 is rotated, the stirring blade 12 rotates, so that a swirling flow around the rotating shaft 11 is generated in the stirring tank 10, and the fluid L accommodated in the stirring tank 10 flows. Stir. In addition, the A line in the figure has shown the liquid level of the fluid L during stirring rotation.
[0009]
In FIG. 1, a Max blend blade (Max Blend is a registered trademark of Sumitomo Heavy Industries, Ltd.) is shown as an example of the stirring blade 12, but a swirling flow may be generated in the entire stirring tank 10. As long as it is possible, any shape such as a paddle blade, an inclined paddle blade, a turbine blade, or an anchor blade may be used.
[0010]
As shown in FIG. 1, an external pipe 13 that communicates between the side surface and the bottom surface of the stirring tank 10 is provided outside the stirring tank 10. In this external pipe 13, one end attached to the side surface of the stirring tank 10 is attached below the liquid level of the liquid stored in the stirring tank 10, and one end attached to the bottom surface of the stirring tank 10 is the stirring tank 10. It is attached to the center of the bottom.
In addition, an external processing device 14 is interposed in the external pipe 13. The external processing device 14 is, for example, a heat exchanger or an external light irradiation device, and can heat the fluid L or apply light to promote the reaction of the fluid L in the stirring tank 10.
The external processing device 14 is not limited to the above-described one, and a measuring device for continuously measuring the characteristics of the fluid L, a charging device for charging a trace component into the fluid L, and a solid contained in the fluid L are separated. Any device such as another external filter may be used.
[0011]
For this reason, if the rotating shaft 11 is rotated, the fluid L in the stirring tank 10 is stirred by the stirring blade 12, so that a swirling flow around the rotating shaft 11 is formed in the stirring tank 10. The pressure in the vicinity of the side surface of the stirring tank 10 is higher than the pressure at the center of 10. Then, in the external pipe 13, the pressure at one end attached to the side surface of the stirring tank 10 is higher than the pressure at one end attached to the bottom surface of the stirring tank 10, and the external pipe 13 is connected to the external pipe 13 from the side face of the stirring tank 10. A flow toward the bottom surface of the stirring tank 10 is formed. That is, even if a mechanical device such as a pump is not attached to the external pipe 13, the fluid L in the agitation tank 10 can be flowed through the external pipe 13 to be externally circulated.
Moreover, if the rotational speed of the rotating shaft 11 is increased, the difference between the pressure at the center of the stirring tank 10 and the pressure in the vicinity of the side surface of the stirring tank 10 can be increased, so that the flow rate of the fluid L flowing in the external pipe 13 is increased. be able to. Conversely, if the rotational speed of the rotating shaft 11 is lowered, the difference between the pressure at the center of the stirring tank 10 and the pressure in the vicinity of the side surface of the stirring tank 10 can be reduced, so the flow rate of the fluid L flowing in the external pipe 13 is reduced. Can be made.
[0012]
Next, the baffle 20 will be described.
As shown in FIG. 1, a plurality of baffles 20 are provided inside the stirring tank 10 along the inner surface of the stirring tank 10. The baffle 20 is provided so as to intersect the swirling direction of the fluid L generated in the stirring tank 10 when the rotating shaft 11 is rotated, that is, the swirling flow around the rotating shaft 11.
For this reason, if the fluid L swirling around the rotating shaft 11 collides with the baffle 20, the fluid L flows upward along the baffle 20. When the upward flow reaches the liquid level, the upward flow flows toward the center of the swirling flow around the rotating shaft 11 having a low pressure. That is, if the fluid L swirling around the rotating shaft 11 collides with the baffle 20, a circulating flow intersecting with the swirling flow around the rotating shaft 11 is formed in the stirring tank 10.
[0013]
Further, since the baffle 20 becomes a flow resistance of the swirling flow around the rotating shaft 11, the baffle 20 has an effect of adjusting the speed of the swirling flow around the rotating shaft 11. And the pressure difference between the vicinity of the side surface of the stirring tank 10 can be changed. For this reason, the flow rate of the fluid L flowing through the external pipe 13 can be increased or decreased by the baffle 20.
[0014]
Therefore, when the rotation speed of the rotating shaft 11 is constant, if the length of the baffle 20 is increased, the flow resistance of the swirling flow around the rotating shaft 11 increases, so that the circulating flow in the stirring vessel 10 becomes stronger. . Moreover, since the speed of the swirling flow around the rotating shaft 11 is slow, the pressure difference between the center in the stirring tank 10 and the vicinity of the side surface of the stirring tank 10 can be reduced, and the flow in the external pipe 13 is achieved. The flow rate of the fluid L can be reduced.
On the contrary, if the length of the baffle 20 is shortened, the flow resistance of the swirling flow around the rotating shaft 11 is reduced, so that the circulating flow in the stirring vessel 10 is weakened. In addition, since the speed of the swirl flow around the rotating shaft 11 is increased, the pressure difference between the center in the stirring tank 10 and the vicinity of the side surface of the stirring tank 10 increases, and the fluid L flowing in the external pipe 13 flows. The flow rate can be increased.
[0015]
Instead of expanding and contracting the length of the baffle 20, the cross-sectional shape of the baffle 20 may be changed.
For example, as shown in FIG. 2, when the cross section of the baffle 20 is circular, that is, when the baffle 20 is a pipe, the outer peripheral surface of the baffle 20 approaches a streamline, and thus resistance to the swirling of the fluid L around the rotating shaft 11. Can be reduced. For this reason, even if the baffle 20 is extended to the vicinity of the bottom surface of the stirring tank 10, the vertical circulation flow in the stirring tank 10 does not become too strong, and the fluid L is reliably mixed in the entire stirring tank 10. can do.
That is, if the surface of the baffle 20 facing the swirl direction of the fluid L around the rotating shaft 11 is brought close to the streamline shape while keeping the length of the baffle 20 constant, the rotating shaft 11 is centered. The flow resistance of the swirling flow can be reduced. Further, if the surface of the baffle 20 facing the swirl direction of the fluid L centered on the rotating shaft 11 is brought close to a plane, the flow resistance of the swirling flow centered on the rotating shaft 11 can be increased.
Moreover, since the length of the baffle 20 can be made constant, the strength of the circulating flow in the agitation tank 10 can be changed while the region where the fluid L is agitated is kept constant in the agitation tank 10.
[0016]
The cross-sectional shape of the baffle 20 is not limited to a circle but may be an ellipse or a triangle having a vertex at a portion facing the swirl direction of the fluid L in order to reduce the resistance to swirl flow. If it is a shape which can make flow resistance small, there will be no limitation in particular.
Furthermore, the cross-sectional shape of the baffle 20 may be a quadrangle or a triangle whose bottom surface is the surface facing the swirl direction of the fluid L in order to increase the resistance to swirl flow. If it is the shape which can do, there will be no limitation in particular.
[0017]
Next, the operation and effect of the external circulation type stirring device 1 of the present embodiment will be described.
When the rotating shaft 11 is rotated, a swirling flow around the rotating shaft 11 is generated in the stirring tank 10, and the fluid L in the stirring tank 10 flows through the external pipe 13 to perform external circulation.
[0018]
When the flow rate of the fluid L flowing through the external pipe 13 is decreased and the circulation flow in the stirring tank 10 is also weakened, the rotation speed of the rotating shaft 11 is decreased and the baffle 20 is shortened. Then, since the pressure difference between the center of the stirring tank 10 and the vicinity of the side surface of the stirring tank 10 is reduced, the flow rate of the fluid L flowing through the external pipe 13 can be reduced. Moreover, since the baffle 20 is short, the resistance to the swirling flow around the rotating shaft 11 in the stirring tank 10 is small, and the circulating flow in the stirring tank 10 can also be weakened.
[0019]
Further, when the flow rate of the fluid L flowing through the external pipe 13 is increased and the circulating flow in the stirring vessel 10 is also strengthened, the rotational speed of the rotating shaft 11 is increased and the baffle 20 is lengthened. In this case, if the rotational speed of the rotating shaft 11 is increased, the difference between the pressure at the center of the stirring tank 10 and the pressure in the vicinity of the side surface of the stirring tank 10 increases, so the flow rate of the fluid L flowing through the external pipe 13 increases. Moreover, since the resistance to the flow of the swirling flow around the rotating shaft 11 is increased, the circulating flow in the stirring tank 10 can be strengthened.
[0020]
If the circulation flow in the agitation tank 10 is weakened and the flow rate of the fluid L flowing through the external pipe 13 is increased, the baffle 20 may be shortened while keeping the rotational speed of the rotating shaft 11 constant. In this case, the resistance of the baffle 20 with respect to the flow of the swirling flow around the rotating shaft 11 is reduced, and the circulating flow in the stirring vessel 10 is weakened. And since the resistance of the baffle 20 becomes small, the speed of the swirl flow centering on the rotating shaft 11 becomes high, and the pressure difference between the center in the stirring tank 10 and the side surface vicinity of the stirring tank 10 becomes large. Therefore, the flow rate of the fluid L flowing through the external pipe 13 can be increased.
[0021]
On the contrary, when the flow rate of the fluid L flowing through the external pipe 13 is reduced to increase the circulation flow in the stirring tank 10, the baffle 20 may be lengthened while keeping the rotation speed of the rotating shaft 11 constant. In this case, the resistance of the baffle 20 with respect to the flow of the swirling flow around the rotating shaft 11 is increased, and the circulating flow in the stirring vessel 10 is increased. And since the speed of the swirl flow centering on the rotating shaft 11 becomes slow by the resistance of the baffle 20, the pressure difference between the center in the stirring tank 10 and the vicinity of the side surface of the stirring tank 10 becomes small, and the external pipe 13 The flow rate of the fluid L flowing through the can be reduced.
[0022]
In addition, what is necessary is just as follows when changing the cross-sectional shape of the baffle 20 and controlling the flow volume of the fluid which flows in the external piping 13, and the flow in the stirring tank 10. FIG.
When the flow rate of the fluid L flowing through the external pipe 13 is decreased and the circulating flow in the stirring tank 10 is also weakened, the rotational speed of the rotating shaft 11 is decreased and the baffle 20 has the fluid L centered on the rotating shaft 11. The surface facing the turning direction is brought closer to the streamlined shape.
Further, when the flow rate of the fluid L flowing through the external pipe 13 is increased and the circulating flow in the stirring tank 10 is also strengthened, the rotational speed of the rotating shaft 11 is increased and the fluid around the rotating shaft 11 in the baffle 20 is increased. The surface facing the turning direction of L is brought close to a plane.
Furthermore, when the circulation flow in the stirring tank 10 is weakened and the flow rate of the fluid L flowing through the external pipe 13 is increased, the rotation shaft 11 is centered on the rotation shaft 11 in the baffle 20 while keeping the rotation speed of the rotation shaft 11 constant. The surface facing the swirling direction of the fluid L to be moved may be close to a streamlined type.
Conversely, when the flow rate of the fluid L flowing through the external pipe 13 is reduced to increase the circulation flow in the stirring tank 10, the rotation shaft 11 is centered in the baffle 20 while keeping the rotation speed of the rotation shaft 11 constant. The surface facing the swirl direction of the fluid L may be brought close to a plane.
[0023]
【The invention's effect】
According to invention of Claim 1, if the rotation speed of a rotating shaft and the length of a baffle are adjusted, the flow volume of the fluid which flows through external piping and the flow state of the fluid in a stirring tank can be adjusted simultaneously .
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view of an external circulation type stirring device 1 of the present embodiment.
FIG. 2 is a schematic cross-sectional view of an external circulation type stirring apparatus 1B according to another embodiment, in which (A) is a vertical cross-sectional view and (B) is a cross-sectional view.
FIG. 3 shows a conventional external circulation type stirring device 100.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 External circulation type stirring apparatus 10 Stirrer tank 11 Rotating shaft 12 Stirring blade 13 External piping 20 Baffle L Fluid

Claims (1)

An agitation tank for containing a fluid; a rotary shaft vertically and rotatably provided in the agitation tank; and an agitation blade attached to the rotation axis for agitating the fluid contained in the agitation tank; In the external circulation type stirring device provided with an external pipe that communicates between the side surface and the bottom surface outside the stirring tank, a control method for controlling the flow rate of the fluid flowing in the external pipe,
In the stirring tank, a baffle is provided so as to intersect the swirling direction in the horizontal plane of the fluid in the stirring tank,
A method for controlling an external circulation amount of an external circulation type stirring device, wherein the flow rate of the fluid flowing in the external pipe is increased or decreased by changing the length of the baffle.

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