JPS59127636A - Mixing apparatus - Google Patents

Abstract

PURPOSE:To perform sufficient and uniform mixing within a short time, by attaching a stirring blade constituted by using a disk having a plurality of coaxial circular grooves provided to the single surface of both surfaces thereof to a rotary shaft in one step or plural steps so as to cross said rotary shaft at right angles at the central part thereof. CONSTITUTION:A roughly mixed liquid 2 being mixed in a mixer 1 is supplied to the bottom part of a mixing tank 6 by a pump 4. A stirring medium 7 is reversely introduced into the mixing tank 6 from a supply port 32 and the liquid supplied to the bottom part of the mixing tank 6 is flowed toward the axial center and enters a gap 23 through the openings 22 of grooved disks 20A, 20B. Subsequently, the liquid successively enters the grooves 24 of the grooved disks 20A, 20B and injected toward the cylindrical wall of the mixing tank 6 while the injected liquid is flowed toward the direction of a rotary shaft 12 through the blade gap between stirring blades and again enters the gap 23 from the openings 22. During this time, the liquid is uniformly mixed while repeatedly receiving shear stress in the gap 23 of the grooved disks 20A, 20B.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mixing device, and more particularly to a mixing device suitable for use in manufacturing a relatively high viscosity magnetic paint and the like that targets fine particles.

Mixing equipment is widely used in industries that manufacture paints, dyes, inks, cosmetics, and various coating materials. Recently, in order to improve quality and expand applications, the particles that can be mixed are becoming smaller and smaller, and their viscosity is increasing. In general, microparticles have strong adhesion and agglomeration properties, making it difficult to mix them uniformly on a microscopic level, and as the viscosity of the system increases, it becomes even more difficult to apply the force necessary for mixing the particles, making mixing even more difficult.

Conventionally, as a device for uniformly mixing solid particles of 0.1 μm to several μm with a liquid such as a resin solution, the first
The sand grinder shown (U.S. Pat. No. 25814)
No. 14). This mixing device includes a cylindrical mixing tank 6,
It is composed of a stirring medium 7 such as glass beads or alumina balls of 1 to 2 mm to be filled in a mixing tank 6, and about 10 discs 8 attached to a rotating shaft 12.

The rough mixed liquid 2 roughly mixed by the rough mixer 1 is passed through the valve 3.
The water is supplied to the bottom of the mixing tank 6 by the pump 4 via the check valve 5. The liquid supplied to the bottom of the mixing tank 6 is
The centrifugal force of the disk 8 causes the liquid to be blown off toward the inner wall of the mixing tank 6 by the kinetic energy of the disk 8 through the stirring medium and viscous resistance. During this time, the liquid is mixed uniformly due to shear stress due to the difference in flow velocity between the stirring medium 7 and the liquid. After the stirring medium 7 is separated from the uniformly mixed liquid by the screen 11, the liquid is taken out of the system as a processing liquid 13.

According to the above device, the centrifugal force of the disk 8 can apply a shearing stress between the stirring medium 7 and the liquid due to the difference in flow velocity, so that the liquid can be mixed uniformly.

However, when mixing liquids uniformly using the disk 8 of the above device, a large amount of stirring medium 7 must be used for mixing for a relatively long time, and a large amount of stirring medium 7 must be used.
is subjected to rotational force of the disk 80 and is worn out due to collision with the surface of the disk 8 and the inner wall of the mixing tank 6, and the agitated medium 7 is so large that when it is separated from the liquid by the screen 11, the screen is clogged. easy. For this reason, it becomes necessary to frequently clean the screen 11, resulting in drawbacks such as reduced maintainability and operability due to continuous operation. Furthermore, since mixing is performed via the viscosity of the liquid, when the liquid becomes highly viscous, the rotational power is transmitted to the stirring medium 7 and the liquid only near the surface of the disk 8. Blind spots are likely to occur between the paints and near the shaft, and uniform mixing due to continuous operation is insufficient, leading to a decline in the quality of paints, etc.

The present invention was made to improve the above-mentioned drawbacks of the prior art, and its purpose is to reduce the amount of stirring medium used by using stirring blades that provide a large mixing force. It is also an object of the present invention to enable thorough and uniform mixing in a short time without using a stirring medium, thereby improving the maintainability and operability of the apparatus.

As a result of studying stirring blades to achieve the above purpose,
In order to achieve uniform mixing of the liquid by applying a large mixing force to the liquid without using an agitation medium or with a small amount of agitation medium, it is possible to use a disk with a plurality of concentric grooves on one or both sides of the agitation blade. The stirring blades may be installed perpendicularly to the rotating shaft at the center of the cylindrical mixing tank in one or more stages. If the grooves, that is, the crests, are mounted on the rotating shaft so that the ridges face each other, and the gap between the two disks is minimized, and the agitator blade is formed by opening the vicinity of the axis of both disks, the shear flow of the liquid can be further improved. It has been found that it is possible to increase the size and achieve a good degree of uniform mixing.

Embodiments of the present invention will be described below with reference to FIGS. 2, 3, and 4. FIG. 2 is an overall flow diagram, and components similar to or identical to those in FIG. 1 are indicated using the same reference numerals. FIG. 3 is a sectional view of a pair of stirring blades, and FIG. 4 is a view taken along the line A--A in FIG. 3.

First, as shown in FIG. 2, the stirring blade is composed of disks 2OA and 20B. As shown in FIGS. 3 and 4, these discs 20A and 20B are provided with a plurality of grooves 24 centered on the shaft on the opposing surfaces of each of the discs 2OA and 20B, and the vicinity of the shaft is opened. It's 22 years old. Furthermore, the grooves 24 and protrusions 25 of the discs 20A and 20B are made to face each other, and each disc 20
The gap 23 between A and 20B is extremely narrow. The dimension l of the gap 23 can be adjusted by the spacer 27, and when no stirring medium is used, the dimension l can be adjusted to 0 by this spacer 27vc.
．． Preferably three fins. The disk 20A is connected to the cylinder 26A, and the disk 20B is connected to the cylinder 26B and fixed to the rotating shaft 12. The operation will be explained below.

In FIG. 2, the crude liquid mixture 2 roughly mixed by the mixer 1 is pumped through the check valve 5 by the pump 4 with the pulp 3 opened.
After that, it is supplied to the bottom of the mixing tank 6. Furthermore, the stirring medium 7 is fed in from the supply port 32 if necessary. The liquid supplied to the bottom of the mixing tank 6 flows 1 toward the axial center due to the rotational force of the blades, and the liquid flows through the openings 22 of each grooved disk 2OA and 20B.
It then enters the gap 23. The liquid that has entered the gap 23 sequentially enters the grooves 24 of each of the grooved disks 2OA and 20B, and is sprayed toward the inner wall of the mixing tank 6. During this time, the liquid is transferred to each grooved disk 2O.
Shear stress acts between the grooves 24 and protrusions 25 of A and 20B, and the liquids are mixed. The liquid injected toward the inner wall of the mixing tank 6 flows toward the rotating shaft 12 through the gap 21 between the stirring blades, and enters the gap 23 through the opening 22 again. During this time, the liquid flows into the gap 2 between each grooved disc 2OA and 20B.
In step 3, the shearing stress is repeatedly applied and the mixture is uniformly mixed. The uniformly mixed liquid is taken out of the system as a processing liquid 13.

According to this embodiment, the gap 23 between the disks 2OA and 20B is made extremely narrow, and a plurality of concentric grooves 24 centered on the shaft 12 are provided on the opposing surfaces of each disk 2OA and 20B. The mixed liquid passes through the grooves 24 in the centrifugal direction, and the injection velocity toward the inner wall of the mixing tank 6, that is, the shear flow increases. especially,
The shear flow of the mixed liquid increases between the protrusions 25, and the shearing force applied to the liquid can be increased. Therefore, uniform mixing of the liquid can be achieved by using a small amount of stirring medium 7 without using a large amount of stirring medium 7 as in the conventional case, and even when no stirring medium 7 is used at all, the liquid can be mixed uniformly. In addition, since only a small amount of the stirring medium 7 is used, there is less clogging of the screen 11 of the stirring medium 7, which wears out, and there is no need to provide the screen 11 when the stirring medium 7 is not used. The blockage will be cleared. Therefore, it is possible to prevent deterioration in mixing maintainability and operability. Furthermore, in this embodiment, since the disks 2OA and 20B are provided with holes 22 near the shaft, the mixed liquid flows easily toward the center of the shaft, and there is an effect that no blind spot is created between the rotary blades.

Note that the stirring blade for achieving uniform mixing of liquids according to the present invention is not limited to the above embodiment, and for example, as shown in FIG. It may be provided with a plate 30. Further, as shown in FIG. 6, the stirring blade may be composed of a double-sided grooved disk 31 having the grooves 24 on both sides, and the stirring blades shown in FIGS. The same effect as the stirring blade can be obtained.

Next, the present invention will be explained in detail using specific examples.

Example I Co deposition - Fe203 magnetic powder 70 parts by weight VAGH (manufactured by U.C.C., USA, 20 chloride/vinyl acetate/vinyl alcohol copolymer) Polyurethane resin 10 Stearic acid 0.7 parts by weight Methyl isobutyl ketone 60 Toluene
A mixture having a composition of 60% was roughly mixed in a rough mixer 1 using the mixing apparatus shown in FIG. Next, this crude mixed liquid was supplied to the bottom of the mixing tank 6 having an internal volume of 20/cm, and 127 glass beads 7 (stirring medium) were supplied from the supply port 32 . Next, the rotary shaft 12 was rotated to rotate the stirring blades to sufficiently stir and mix the crude liquid mixture, and then the glass beads 7 were separated by the screen 11, and the treated liquid was taken out from the mixing tank. The magnetic paint prepared by this mixing was applied onto a polyester base film having a thickness of 12 .mu.m to a dry thickness of 5 .mu.m and dried to produce a magnetic tape.

Example 2 In Example 1, the amount of glass beads 7 used was 121!
A magnetic tape was produced in the same manner as in Example 1 except that the magnetic tape was changed from 61 to 61.

Example 3 A magnetic tape was produced in the same manner as in Example 1 except that the glass beads 7 were omitted.

Comparative Example A magnetic tape was produced in the same manner as in Example 1, except that the mixing tank 6 having an internal volume of 201 shown in FIG. 1 was used in place of the mixing tank in Example 1.

In each Example and Comparative Example, the time required for dispersing the magnetic paint in the mixing tank until the surface roughness of the obtained magnetic tape reached a predetermined roughness was measured.

The table below shows the results.

As is clear from the table above, the dispersion time of the magnetic paint obtained using the mixing device of the present invention (Examples 1 to 3) is the same as the dispersion time of the magnetic paint obtained using the conventional mixing device. (Comparative Example) This shows that the mixing device of the present invention takes less time to achieve uniform mixing and improves the mixing and dispersing effect of magnetic paints and the like.

[Brief explanation of drawings]

Fig. 1 is a 70-page diagram of the entire mixing process using a conventional mixing device, Fig. 2 is a 70-page diagram of the entire mixing process using the mixing device of the present invention, and Fig. 3 is a 70-page diagram of the entire mixing process using the mixing device of the present invention. FIG. 4 is a cross-sectional view showing an example of the stirring blade used in the present invention, FIG. 4 is a view taken along the line A-A in FIG. 3, and FIG. FIG. 6 is a sectional view showing the same and other embodiments. 6... Mixing tank, 7... Stirring medium, 12... Rotating shaft, 2OA, 20B, 31... Grooved disc, 24... Groove, 30... Disc in Figure 1 Figure 2

Claims (1)

[Claims] 1. A rotating shaft is rotatably attached to the center of a cylindrical mixing tank, and one stage or a number of stirring blades are mounted on the rotating shaft, each of which is composed of a disk having a plurality of concentric grooves on one or both sides. A mixing device for mixing a plurality of liquids or a liquid and a solid, characterized in that it is installed perpendicularly to the stage rotation axis at the center.