JPS6249099B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a stirring device that can be applied to mixing and stirring a wide range of viscous fluids ranging from a low viscosity region to a high viscosity region. Conventionally, various types of stirring blades have been used to stir fluids depending on the properties of the fluid, such as viscosity.Among them, helical ribbon blades are often used as suitable for stirring fluids with relatively high viscosity. . However, even when a high viscosity fluid is stirred using such helical ribbon blades,
There are problems as listed below. (1) A fixed point where no fluid flows is formed between the vicinity of the helical ribbon blade and the center of the tank, resulting in poor stirring efficiency as a whole. (2) When the Reynolds number Re is Re > 100, the fluid rotates with the blades, forming a solid rotating part, and the mixing ability is extremely reduced. (3) Since helical ribbon blades have poor fluid dispersion power, when dispersing or dissolving particles in a high viscosity fluid, the particles aggregate and require a long time for dispersion or dissolution. (4) When the viscosity of the fluid changes with dissolution, such as when a water-soluble polymer is swollen and dissolved in a fluid, efficient stirring cannot be performed over the entire viscosity range. The present invention has been made in view of these points, and in addition to helical ribbon blades that rotate along the inner circumferential wall of the tank body, paddle blades that rotate in the opposite direction to the blades are provided at the center of the tank body, The feature is that the stirring ability is significantly improved through the interaction of these two blades. Hereinafter, embodiments of the present invention will be described in detail based on the drawings. In FIGS. 1 and 2, reference numeral 1 denotes a tank body such as an emulsification tank that accommodates a fluid to be stirred inside; A heating and cooling jacket is attached to the outer periphery of the main body 1 as required. Inside the tank body 1, a mounting frame 3 attached to a helical ribbon blade drive shaft 2 is rotatably arranged, and around the mounting frame 3 a plurality of helical ribbon blades 4 are arranged out of phase with each other. . Further, a paddle blade drive shaft 6 that rotates in the opposite direction to the helical ribbon blades 4, 4 is vertically installed in the center of the tank body 1, and a plurality of paddle blades 7, 7 are mounted on the drive shaft 6.
are installed radially to form upper and lower paddle blade groups 8, 8, and these paddle blades 7,
The swirling flow generated by the helical ribbon blades 4 is tilted in a direction that can be converted into an axial flow opposite to the axial flow near the inner circumferential wall of the tank body 1, and the fluid in the tank body 1 is made to flow in opposite directions. Two types of blades 4 and 7 rotating in the direction are configured to circulate convectionally. The number of the helical ribbon blades 4 may be one, and the paddle blades 7 constituting the paddle blade group 8 may be
The number is about 2 to 4 and the number is 30 to 60.
It is preferable that the paddle blade group 8 be attached to the drive shaft 6 at an inclination angle of .degree., and that the number of mounting stages of the paddle blade group 8 is two stages when H/D=1, and the number of stages is increased by one stage each time H/D increases by 0.5. Further, the mutual positional relationship of the upper and lower paddle blade groups can be set in a series state at exactly the same angle, or in a parallel state shifted by a predetermined angle. In the stirring device having the above configuration, the tank body 1
When the tank body 1 is filled with fluid and the helical ribbon blades 4 and paddle blades 7 are rotated in opposite directions as shown by the arrows by the drive shafts 2 and 6, the helical ribbon blades 4 generates a swirling flow in the direction of rotation and a downward axial flow, while in the center of the tank body 1, due to the deflection plate-like action of the paddle blades 7 rotating in the opposite direction. As a result, the swirling flow is disturbed and at the same time is converted into a strong upward axial flow, forming a flow that circulates greatly in the axial direction while swirling as a whole. Further, locally, a small circulation flow is formed around the helical ribbon blade 4 and the paddle blade 7 in a direction surrounding them, and the fluid is stirred by the interaction of these flows. Therefore, even when the Ray-nozzle number Re is Re > 100, the phenomenon in which the fluid swirls together with the helical ribbon blade due to the influence of inertia and forms a solid rotating part is suppressed; on the other hand, when Re < 100, The paddle blades further strengthen the axial flow in the center of the tank, and in both cases the stirring effect is significantly improved. In addition, when dispersing or dissolving particles, the surface of the fluid is disturbed by the reinforcement of the axial flow by the paddle blades 7, etc., and a strong dispersion force is applied to the inside of the fluid, so that the particles are supplied to the surface of the fluid. agglomeration is prevented and uniform dispersion or dissolution in the fluid is promoted in a short period of time. Furthermore, when the viscosity of the fluid changes with stirring, such as when a water-soluble polymer is swollen and dissolved in the fluid, the paddle blades 7 in the center act effectively while the viscosity of the fluid is low. As the height increases, the function of the helical ribbon wing 4 gradually increases. That is, two types of blades with different optimum viscosity ranges work effectively to alternately compensate for the defects of the other blade in the process of fluid viscosity change, thereby achieving efficient stirring over a wide viscosity range. Note that the rotational speed of the wings 4 and 7 can be arbitrarily changed depending on the viscosity of the fluid. Next, using the stirring device according to the present invention and a conventional stirring device equipped with only helical ribbon blades, a particle dispersion and dissolution experiment was conducted in a tank with a capacity of 20. The results are shown in the following table.

[Table] As described above, according to the stirring device according to the present invention,
By using a combination of helical ribbon impellers and paddle impellers that rotate in opposite directions, it is not only possible to use the fluid in a very wide viscosity range, but also significantly improves the stirring ability over the entire Reynolds number range. It is ideal for dispersing or dissolving particles in high viscosity fluids, swelling and dissolving polymers in fluids, etc.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
The figure is a plan view thereof. 1...tank body, 4...helical ribbon wing, 6...
...Drive shaft, 7...Paddle blade.

Claims (1)

[Claims] 1 A helical ribbon blade that is rotationally driven along the inner circumferential wall of the tank body is arranged, and paddle blades that are driven in the opposite direction to the helical ribbon blade are radially attached to a drive shaft provided in the center of the tank body. In addition, these paddle blades are tilted in a direction capable of converting the swirling flow of fluid generated by the helical ribbon blade into an axial flow opposite to the axial flow near the inner peripheral wall of the tank body. stirring device.