JPH0761439B2 - Stirrer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stirrer, for example, a stirrer used for the purpose of stirring and mixing liquid or slurry substances, reaction and the like.

[0002]

2. Description of the Related Art Conventionally, as a stirring blade of a stirring device, a paddle blade, a turbine blade, a propeller blade, a multistage paddle blade, etc. have been used for a fluid having a relatively low viscosity, and for a fluid having a high viscosity. Helical ribbon wings and screw wings are used.

[0003]

The above-mentioned conventional stirring device using the stirring blade has the following problems.

(1) When a low-viscosity stirring blade (paddle blade, turbine blade, propeller blade, multistage paddle blade, etc.) is used, the circulation flow of the material to be stirred in the stirring tank is limited to the vicinity of the stirring blade. There is a problem that the mixing performance is low because a circulation flow is formed over the entire tank, and the stirring power is consumed only in the vicinity of the stirring blades, so that the power characteristics are poor.

(2) When using a high-viscosity stirring blade (helical ribbon blade, screw blade, etc.), excellent mixing performance is exhibited for a high-viscosity liquid (several hundreds to 1000 poise or more). However, with respect to a liquid having a relatively low viscosity (a liquid having several hundreds to 1000 POISE or less), a circulating flow in the tank is not formed and the mixing performance is low. Further, this type of wing has drawbacks that it is difficult to manufacture because of its complicated shape, the cost is high, and the cleaning is not easy when the operation is stopped.

(3) In both the low-viscosity stirring blade and the high-viscosity stirring blade, a stirring shaft for mounting the stirring blade is provided at the center of rotation of the stirring blade. Since the peripheral speed of the stirring blade rotation center is low, this part locally causes poor mixing (dead space), and in the vicinity of the stirring shaft surface, the object to be stirred adheres and solidifies, and There is a possibility that it may be mixed as a foreign matter, and it becomes difficult to ensure the quality uniformity of the agitated object.

The present invention is intended to provide a stirring device which can solve the above problems.

[0008]

SUMMARY OF THE INVENTION A stirring device of the present invention comprises a rotating shaft arranged in an upward direction, and a stirring device vertically arranged at a position different from the axial center position of the rotating shaft and connected to the rotating shaft. A blade mounting bracket, a plurality of small inclined flat plate blades mounted on the side surface of the stirring blade mounting bracket to generate a downward flow, and a large vertical flat plate blade mounted on the lower end of the stirring blade mounting bracket are placed in a stirring tank. It is characterized by being provided.

[0009]

In the stirring device according to the present invention, the stirring blade mounting metal fitting is arranged in the vertical direction at a position different from the axial center position of the rotating shaft arranged in the vertical direction as described above. Section is not provided with a stirring blade mounting bracket, and a large vertical flat plate blade is provided at the lower end of the stirring blade mounting bracket, and a plurality of small inclined flat plate blades that generate downward flow are provided on the side surface. By rotating the stirring blade around the axis of the rotating shaft in the stirring tank, (1) a large vertical plate blade at the lower end causes an upward flow near the inner wall surface of the stirring tank, and (2) a plurality of upper blades. With a small inclined flat plate blade, a downward flow is generated near the center of the stirring tank, and (3) by the above (1) and (2), a flow is formed over the whole area of the stirring tank, and mixing is performed with low power and high efficiency. (4) Furthermore, the stirring blade mounting bracket is rotating during rotation, which is the axis of the rotating shaft. Since not disposed it can be prevented from adhering solid of poor mixing and the agitation was due to the flow defects in the vicinity of the center of rotation.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. As shown in FIGS. 1 to 3,
A vertical rotating shaft 2 is inserted in the center of a cylindrical vertical stirring tank 1 that accommodates two or more types of liquids having different viscosities, and a lower end of the rotating shaft 2 has a shaft coupling 3 interposed therebetween. The centers of the arms 4 arranged horizontally are connected in the longitudinal direction.
The two stirring blade mounting members 5 are connected to both end surfaces of the arm 4 and are arranged so as to extend downward from both end surfaces of the arm 4 and are located at positions apart from the axis of the rotating shaft 2 which is the center of rotation. ing.

At the lower end of the stirring blade mounting member 5, there is mounted the stirring blade mounting member 5, and hence one large vertical flat plate blade 7 arranged parallel to the axis of the rotary shaft 2. The lower end surface of the blade 7 is shaped so as to approach the lower inner wall surface of the stirring tank 1.

Above the large vertical flat blade, a plurality of small inclined flat blades 6 are arranged so as to be parallel to each other, and are attached to the side surfaces of the stirring blade mounting hardware 5. The inclination of the inclined flat blade 6 is the same as that of the inclined flat blade 6 through the stirring blade attachment hardware 5.
Is set in such a direction that a downward flow is generated when the rotating shaft 2 rotates about the axis of the rotating shaft 2. Further, a plurality of baffle plates 8 arranged in the vertical direction are provided on the inner wall surface of the stirring tank 1.

In the present embodiment, by the rotation of the rotary shaft 2 (indicated by the arrow in FIGS. 1 and 3), a large vertical flat blade 7 and a plurality of small inclined flat blades are provided via the arm 4 and the stirring blade 5. 6 rotates around the axis of the rotating shaft 2 in the stirring tank 1.

A radial radial flow of the liquid to be treated is generated at the bottom of the stirring tank 1 by the rotation of the large vertical flat plate blades 7, and the radial flow collides with the bottom wall surface of the stirring tank 1 and The upward flow is upward along the wall of the straight body. This upward flow becomes a flow toward the center of the stirring tank 1 near the liquid surface, and becomes a downward flow due to the plurality of small inclined flat plate blades 6, and the large vertical flat plate blade 7 in the lower part of the tank. Return to.

The baffle plate 8 includes the stirring blades 7,
6 has an action of preventing a swirling flow in the circumferential direction in the tank 1 formed by 6 and promoting formation of an upflow and a downflow in the tank.

In this way, a large circulating flow is formed in the stirring tank 1 over the entire area, and it is possible to achieve highly efficient mixing with low power.

FIG. 4 shows the approximate number 100 to 100 using this embodiment.
It shows the flow state in the stirring tank when a liquid of 1000 POISE or less is stirred, and the flow of the liquid in the stirring tank 1 described above is indicated by an arrow.

From the results of various experiments conducted by the present inventor, in order to achieve a highly efficient mixed state, the diametrical dimension of the large vertical flat blade 7 is set to the diametrical dimension of the small inclined flat blade 6. On the other hand, it is preferably equal to or larger than that, and preferably 50 to 80% of the inner diameter of the stirring tank. Further, the diametrical dimension of the small inclined flat plate blade 6 is preferably 40 to 65% of the inner diameter dimension of the stirring tank.

The tilting direction of the small inclined flat plate blades 6 must be set so that the liquid is discharged downward during rotation as described above, and the number of them can be freely selected according to the height of the liquid surface. can do.

A second embodiment of the present invention will be described with reference to FIG. In this embodiment, a small inclined flat plate blade 6 attached to one of the two stirring blade mounting hardware 5 is attached to the stirring blade mounting hardware 5.
And the small inclined flat plate blades 6 attached to the other stirring blade attachment hardware 5 are arranged so as to be vertically displaced from each other. Also in this embodiment, the same operation and effect as those of the first embodiment can be obtained.

Experimental results showing the effect of the stirring device according to the present invention on the conventional stirring device will be described below.

In a cylindrical container made of transparent acrylic resin having an inner diameter of 290 mm and a height of 600 mm, the density ρ = 1350 kg / m
^3. A starch syrup aqueous solution having a viscosity μ = 0.5 to ₂ kg / m · sec and I ₂ and Na ₂ S ₂ O ₃ were mixed to have the same viscosity and charged separately, and then various stirring blades were rotated at n = 1-4 rps
The mixture was rotated by and the time t (sec) required for the dark brown color of I ₂ to be decolorized with Na ₂ S ₂ O ₃ was measured as the mixing completion time, and the mixing performance data of various stirring blades was acquired. In addition, a torque meter was installed in the drive unit of the stirring blade, the torque during stirring and mixing was measured, and the power consumption data of various blades was acquired.

To compare and evaluate the mixing performance and power characteristics of various blades, the power consumption per unit volume P _v (kw / m
The correlation data of the mixing time t (sec) with respect to ³ ) was obtained.

Mixing time t with respect to power consumption P _v (kw / m ³ ) per unit volume of various stirring blades by the above test
Table 1 shows the correlation data of

[0025]

[Table 1]

According to Table 1, the stirring device of the present invention consumes power P _v (kw) per unit volume as compared with the conventional stirring blade.
It was confirmed that the mixing time t (sec) with respect to / m ³ ) was short and the power characteristics and the mixing performance were excellent.

In the first and second embodiments, two stirring blade attachment fittings are provided, but in the present invention, one or a plurality of three or more are provided. You can also

[0028]

The present invention has the structure described in the claims, and is vertically arranged at a position different from the axial center position of the vertically arranged rotating shaft and is connected to the rotating shaft. Since a large vertical flat plate blade is attached to the lower end of the stirring blade mounting bracket, an upward flow is generated in the object to be treated near the wall surface of the stirring tank due to the rotation of the vertical flat plate blade. Since a plurality of small inclined flat plate blades that generate a downward flow are attached to the side surface, the rotation of the inclined flat plate blades causes a downward flow in the object to be treated in the vicinity of the center of the stirring tank, and the entire inside of the stirring tank. It is possible to form a flow of the material to be stirred and achieve high efficiency mixing with low power.

Further, as described above, since the stirring blade mounting member is not arranged on the axis of the rotating shaft which is the center of rotation, poor mixing of the agitated object due to insufficient flow in the vicinity of the center of rotation and solidification of its adherence may occur. Can be prevented.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of a first embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line I-I and line II-II of FIG.

FIG. 3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is an explanatory diagram of a flow state of the first embodiment.

FIG. 5 is a vertical sectional front view of the second embodiment of the present invention.

[Explanation of symbols]

 1 Stirring tank 2 Rotating shaft 3 Shaft coupling 4 Arm 5 Stirring blade mounting bracket 6 Small inclined flat plate blade 7 Large vertical flat plate blade 8 Baffle plate

Claims (1)

[Claims] 1. A rotary shaft arranged in an upper direction, a stirring blade mounting member vertically arranged at a position different from an axial center position of the rotating shaft and connected to the rotating shaft, and a side surface of the stirring blade mounting member. A stirrer comprising: a plurality of small inclined flat plate blades attached to the bottom of the stirring blade and a large vertical flat plate blade attached to the lower end of the stirring blade mounting bracket.