JPH0761440B2 - 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 liquids or slurry-like substances of different viscosity systems, reaction and the like.

[0002]

2. Description of the Related Art Conventionally, paddle blades, turbine blades, propeller blades, multi-stage paddle blades, etc. have been used as a stirring blade of a stirring device for a fluid having a relatively low viscosity, and a helical blade for a fluid having a high viscosity. Ribbon wings and screw wings are used.

[0003]

An operation of supplying another liquid having a different viscosity to the liquid charged in the stirring tank to uniformly mix two or more kinds of liquids having different viscosities, When so-called hetero-viscous mixing is performed using the conventional stirring blade described above, there are the following problems.

(1) When using a low-viscosity stirring blade (paddle blade, turbine blade, propeller blade, multi-stage paddle blade, etc.), the circulation flow of the material to be stirred in the stirring tank is formed only near the stirring blade. However, since the circulation flow is not formed over the entire tank, the mixing performance is low and the stirring power is consumed only in the vicinity of the stirring blade, so that there is a problem that the power characteristics are poor.

(2) When using a high-viscosity stirring blade (helical ribbon blade, screw blade, etc.), it exhibits excellent mixing performance for high-viscosity liquids (liquids of several hundreds to 1000 POISE or more). However, with respect to a liquid having a relatively low viscosity (a liquid having a porosity of several 100 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 it is not easy to clean when the operation is stopped.

The present invention is intended to provide a stirring device capable of solving the above problems.

[0007]

A stirring device of the present invention is a vertical flat plate in which a rotating stirring shaft arranged vertically is installed in a stirring tank, and the stirring plate is arranged parallel to the axis of the stirring shaft. A plurality of blades composed of a plurality of inclined plate blades arranged in the opposite direction to the blades and the vertical plate blades and having an inclination angle with respect to the axis of the stirring shaft are arranged in the vertical direction so as to generate a downward flow. The vertical flat plate blade and the inclined flat plate blade of the adjoining blade group are offset from each other in orientation.

[0008]

As described above, the stirring device according to the present invention is arranged such that a plurality of blade groups consisting of a vertical flat plate blade and a plurality of inclined flat plate blades are vertically arranged and attached to a stirring shaft, and vertical blades of adjacent blade groups are arranged vertically. Since the orientations of the flat blades and the inclined flat blades are offset from each other and these vertical flat blades and the inclined flat blades are rotated by the stirring shaft in the stirring tank, (1) the vertical flat blades are placed in the stirring tank. Generates an upward flow in the object to be processed near the wall surface,
(2) A downward flow is generated in the object to be treated near the center of the stirring tank by the inclined flat plate blade, and (3) a flow over the entire stirring tank is formed by the above (1) and (2), and two or more types are formed. Liquids with different viscosities can be mixed rapidly and efficiently.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1 to 4, a rotary shaft 2 is inserted into a cylindrical vertical stirring tank 1 containing two or more kinds of liquids having different viscosities, and the rotary shaft 2 has a shaft coupling 3 The stirring shaft 4 is connected via.

Below the stirring shaft 4, a plurality of tilted flat plates 5 and 5 are arranged in a direction opposite to the vertical flat plate blade 5, that is, in a direction opposite to the vertical flat plate blade 5 with respect to the stirring shaft 4. Wings 6
Attached to the lower wing group. The vertical flat plate blades 5 are attached to the stirring shaft 4 so as to be positioned parallel to the axis of the stirring shaft 4, and the plurality of inclined flat plate blades 6 are provided.
1 has an equal inclination with respect to the axis of the stirring shaft 4 so that a downward flow is generated in the liquid to be treated in the stirring tank 1 when the rotating shaft 2 and the stirring shaft 4 rotate in the directions of the arrows in FIGS. They are arranged in parallel at an angle and attached to the stirring shaft 4.

Above the lower blade group composed of the vertical flat plate blades 5 and the plurality of inclined flat plate blades 6, an upper blade group composed of the vertical flat plate blades 7 and the plurality of inclined flat plate blades 8 is attached to the stirring shaft 4. There is. Vertical blades 7 and inclined blades 8 in the upper blade group
Are arranged in the same manner as the vertical flat plate blades 5 and the inclined flat plate blades 6 of the lower blade group and attached to the stirring shaft 4, but as shown in FIGS. 1 to 3, the vertical flat plate blades of the upper blade group are arranged. The azimuths of 7 and the inclined flat blade 8 are offset in the opposite directions with respect to the vertical flat blade 5 and the inclined flat blade 6 of the lower blade group. Further, the upper and lower blade groups arranged in the vertical direction and attached to the stirring shaft 4 as described above are in the range from the position close to the bottom surface in the stirring tank 1 to the vicinity of the liquid level L of the liquid to be treated. It is arranged vertically.

A plurality of baffle plates 9 arranged vertically are provided on the inner wall surface of the stirring tank 1.

In the present embodiment, the stirring shaft 4 is inserted through the rotary shaft 2.
Rotates, and the vertical flat plate blades 5, 7 and the inclined flat plate blades 6, 8 rotate around the axis of the stirring shaft 4 in the stirring tank 1 containing two or more kinds of liquids having different viscosities.

By rotating the vertical flat plate blades 5 and 7, the stirring tank 1 is
A radial flow of the liquid to be treated flowing in the opposite direction toward the inner wall surface of the stirring tank 1 collides with the inner wall surface of the stirring tank 1,
An upward ascending flow follows the wall surface of the straight body part of. This upward flow becomes a flow in the vicinity of the liquid surface L of the liquid to be treated toward the center of the stirring tank 1, and the downward flow is caused by the rotation of the plurality of inclined flat plate blades 6 and 8 arranged in the center of the stirring tank 1. It will be a downward flow.

The baffle plate 9 has the above-mentioned stirring blades 5-5.
8 has an action of preventing the generation of a swirling flow in the stirring tank 1 in the inner circumferential direction and promoting the formation of an ascending flow and a descending flow in the stirring tank 1.

In this way, a large circulation flow is formed in the stirring tank 1 over the entire area, and two or more kinds of liquids having different viscosities can be efficiently mixed.

FIG. 5 shows a flow state in the stirring tank 1 when stirring two kinds of liquids having different viscosities by using the stirring device according to this embodiment. The stirring tank 1 described above is shown.
The flow of liquid inside is indicated by arrows.

From the results of various experiments conducted by the present inventor, in order to achieve a highly efficient mixed state, the radial dimension of the vertical flat plate blades 5 and 7 should be 50 to 80% of the radial dimension of the stirring tank 1. Is desirable. The vertical dimension of the vertical flat blades 5 and 7 is
It is necessary to determine so that the bending moment of the shaft caused by the load acting on the blade during stirring is minimized. Also,
The radial dimension of the upper vertical flat blade 7 is preferably equal to or smaller than that of the lower vertical flat blade 5.

As described above, it is necessary to mount the inclined flat plate blades 6 and 8 in the direction in which the liquid to be treated in the stirring tank 1 is discharged downward to generate a downward flow during rotation. The number of each is two or more.

An experiment conducted by the present inventor 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 , 24 liters of a starch syrup aqueous solution having a viscosity μ = 0.25 to 2.5 kg / m · sec and I ₂ were previously charged and uniformly mixed, and then Na ₂ S ₂ having a viscosity μ = 0.001 kg / m · sec. O
Inject 100 cc of ₃ and rotate various stirring blades n = 1 to 1
Rotation was performed at 4 rps, and the time t (sec.) Required until the dark brown color of I ₂ was decolorized with Na ₂ S ₂ O ₃ was measured as the mixing completion time. Mixed performance data was obtained. 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. The results are shown in Table 1.

[0023]

[Table 1]

From Table 1, it can be seen that the stirring device of the present invention consumes power P _v (kw / m) per unit volume as compared with the conventional stirring blade.
It was confirmed that the mixing time t (sec) for ³ ) was short and the power characteristics and mixing performance were excellent in mixing liquids having different viscosities.

In the above embodiment, two blade groups are provided on the upper side and the lower side, and the azimuths of the vertical flat plate blades and the inclined flat plate blades are opposite to each other. However, the present invention is not limited to this. It is possible to provide three or more blade groups in the vertical direction and to appropriately shift the orientations of the vertical flat plate blade and the inclined flat plate blade of the adjacent blade groups.

[0026]

The present invention has the structure described in the claims, and causes an upward flow in the vicinity of the wall surface of the agitation tank by the rotation of the vertical flat plate blades of a plurality of blade groups, and also a plurality of blades. A downward flow is generated near the center of the stirring tank by the rotation of the inclined flat plate blades of the blade group. Thereby, the flow of the object to be treated can be formed over the entire area of the stirring tank, and in the mixing operation of two or more kinds of liquids having different viscosities, stirring and mixing with low power and high efficiency can be achieved.

[Brief description of drawings]

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

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

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

FIG. 4 is a sectional view taken along the line III-III in FIG.

FIG. 5 is an explanatory diagram of a fluidized state of the embodiment.

[Explanation of symbols]

 1 Stirring tank 2 Rotating shaft 3 Shaft coupling 4 Stirring shaft 5,7 Vertical flat plate blade 6,8 Inclined flat plate blade 9 Baffle plate L Liquid level

Claims (1)

[Claims] 1. A vertically rotating rotating stirring shaft is installed in a stirring tank, and a vertical flat plate blade arranged parallel to the axis of the stirring shaft and an opposite direction to the vertical flat plate blade. A plurality of blades, each of which is composed of a plurality of inclined flat plate blades having an inclination angle with respect to the axis of the stirring shaft so as to generate a downward flow, are attached to the stirring shaft, and adjacent blades are provided. A stirrer characterized in that the vertical plate blades and the inclined plate blades of the group are offset from each other.