JPH0148057B2 - - Google Patents

Description

Detailed Description of the Invention The present invention involves a dispersion machine for producing various dispersions, and in particular, forcibly stirring the media filled in the dispersion chamber to uniformly pulverize various suspensions to be dispersed. Regarding a continuous media type dispersion device for dispersion, the present invention provides a continuous dispersion machine that is more preferably suitable for a series of processes from preliminary dispersion to final dispersion.

Conventionally, in the manufacturing process of various coating agents such as paints, printing inks, colorants, and cosmetics, it is necessary to pulverize and uniformly disperse pigments, waxes, and other materials to be crushed in a liquid medium such as varnish. Therefore, dispersion devices such as batch roll mills, ball mills, and continuous media mills are used. However, in order to improve the workability of these crushing and dispersing operations, prevent product quality fluctuations, save energy, save space, and have a cost advantage, a continuous media type dispersion device that uses a media is preferable to the batch method. It has been widely used.

In addition, a special type of continuous media type dispersion machine does not use the above-mentioned stirring member, but uses a rotor with a special shape as the rotating shaft, and the inner wall of the stator and the outer wall of the rotor are There is also a method in which a small gap is formed in the chamber and used as a dispersion chamber, and the media in the dispersion chamber is stirred by rotation of a rotor. As the media, spherical bodies made of steel, glass, ceramic, or similar materials are used, and the particle size and filling amount are determined depending on the purpose of pulverization and dispersion.

The pulverization or dispersion ability of this media-type dispersion device greatly influences not only its processing ability but also the quality of the dispersion, depending on how effectively the media applies shear stress to the suspension. Therefore, improving the stirring efficiency of the media has been a major issue.

In the case of specific dispersion devices that do not use the above-mentioned stirring member, the stirring effect is improved by increasing the rotational speed of the rotor or by narrowing the gap that forms the dispersion chamber.

However, in this type of dispersion machine, since the media is agitated by the wall of the rotor, there is a limit to the number of rotations in order to prevent wear and tear on the side of the rotor or the inner wall of the stator, which are the main parts of the device. The application is limited to the dispersion operation of specific suspensions that can achieve the desired dispersion under appropriate conditions.

Therefore, it is advantageous in terms of processing capacity, and there are few restrictions on the type and properties (viscosity, hardness, etc.) of the suspension.Moreover, if wear and damage occur, the stirring member can be replaced by replacing only the stirring member. Media agitation type dispersers are widely used.

In a dispersion machine that uses a stirring member to stir the media, in order to efficiently stir the media, the shape of the stirring member may be changed from a pin shape to a disk shape, or a hole may be provided in the disk to form a ring shape or a cam shape. Transform and control the flow of media,
Improvements have been made such as installing pins on the inner wall of the stator to improve the collision speed difference between media, and making the rotating shaft thicker to increase the circumferential speed on the rotor shaft side. .

However, although the above-mentioned improvements to the rotor are effective to some extent in terms of improving the stirring efficiency of the media, they may result in accelerated wear of the stirring member or the media, or may result in excessive wear of the stirring member, rotating shaft, or There is a large difference in the stirring efficiency of the media in each part of the dispersion chamber, and depending on the passing position of the object to be crushed, the object may be subjected to insufficient pulverization and dispersion, resulting in the so-called short pass phenomenon in which the object passes through as coarse particles. Otherwise, a so-called blockage phenomenon occurs in which the media is concentrated in one area or at the discharge port, which causes problems in mechanical aspects, quality aspects, work aspects, and even energy efficiency.

Therefore, it may significantly shorten the life of the dispersion device,
The stirring member had to be replaced frequently. Furthermore, the phenomenon of shot pass of unpulverized coarse particles causes variations in the particle size of the particles to be crushed in the dispersion, making it difficult to obtain an ideal dispersion that is uniform and has a sharp particle size distribution. For products such as coating and printing inks where the degree of dispersion directly affects the quality and performance of the product, the presence of coarse particles and the broadening of the particle size distribution of the dispersion pose major problems.

As a result of intensive research to solve the above-mentioned problems of conventional devices, the present inventor has developed an excellent continuous media type dispersion device that solves these problems.

That is, in the present invention, a portion surrounded by the inner wall of the stator, the outer wall of the rotor, and the media separator is used as a dispersion chamber, and the dispersion chamber is filled with media,
A rotor stirring member is fixed to the outer wall of the rotor, and in a continuous media type dispersion machine, the suspension is continuously pulverized and dispersed by forcibly stirring the media through the rotation of the rotor. The shape is a combination of an inverted conical top and a cylindrical shape, and the inner wall of the stator is also shaped to correspond to the shape of the rotor, making it a continuous media with a constant spacing between the outer wall of the rotor and the inner wall of the stator. Provide type disperser.

Hereinafter, the continuous media type disperser according to the present invention will be explained in more detail using the drawings.

FIG. 1 shows a cross-sectional view of a specific example of a continuous media type dispersion machine, and the dispersion machine has an inverted cone-shaped rotor to which a stirring member is attached, and a shape corresponding to the rotor. The inner wall of the stator is also characterized.

Reference numeral 11 indicates an inner wall of the stator, and reference numeral 12 indicates an outer wall of the inverted conical rotor. A dispersion chamber 13 is also constituted by the portion surrounded by the inner wall of the stator, the outer wall of the inverted conical rotor, and the media separator. The dispersion chamber is filled with a predetermined amount of media 14, and is forcibly stirred by the rotation of the inverted conical rotor outer wall 12 and the stirring member 15 attached to the outer wall. Further, a medium passage 24 for cooling or heating is formed on the outside of the inner wall of the stator, and a medium passage 20 for cooling or heating is formed inside the inverted conical rotor as necessary. . Then, the suspension to be dispersed is supplied from the inlet 17 by pressure supply means or the like.
The dispersion is continuously supplied, pulverized and dispersed in the dispersion chamber, and the dispersion is separated from the media by the media separator 18 and continuously discharged from the discharge port 19.

In the above disperser, the outer wall of the rotor and the inner wall of the stator are formed to have an inverted conical shape, so when the rotation axis of the rotor rotates at a constant angular velocity, ω, the rotation near the suspension inlet The circumferential velocity v ₁ at the tip of the stirring member on the child outer wall (for example, at a radius of r ₁ from the rotation axis) is denoted by ω.r ₁ , and the circumferential velocity v 1 at the tip of the rotor stirring member near the discharge port (for example, at a radius of r 1 is r ₂ ), the circumferential speed v ₂ is similarly ω・r ₂
It is indicated by. For example, if the distance from the tip of the stirring member to the inner wall of the stator is constant (distance x), the shear rates e ₁ and e ₂ between the tip of the stirring member and the inner wall of the stator are e ₁ = ω・r ₁ /x e ₂ = ω・r ₂ /x, and since r ₂ > r ₁ , the shear rate between the rotor outer wall and its stirring member and the stator inner wall gradually increases from the rotor inlet side to the discharge port. It will increase.

By specifying the shape of the rotor and the shape of the inner wall of the stator as described above, even if the rotor rotates at the same number of revolutions, it is possible to agitate the media at a relatively gentle shear speed near the inlet. The suspension is pulverized and dispersed, and the shear rate is gradually increased to increase the stirring force, and near the discharge port, the media is stirred, that is, pulverized and dispersed, at the highest shear rate. When the particle size of the object to be dispersed is large, it can be pulverized relatively easily compared to when the particle size is fine, but as the object to be pulverized becomes finer, pulverization becomes more difficult and requires higher energy. Therefore, as the grinding and dispersion work progresses in the dispersion chamber, stirring at a higher shear rate becomes possible, and a finer dispersion can be obtained. For example, it can be applied to a series of treatments to create a dispersion liquid containing particles with a maximum size of about 5 μm from a premix containing particles with a maximum size of about 2000 μm (2 mm).

Furthermore, by forming the dispersion chamber of the device into the shape specified above, the volume of the dispersion chamber per unit traveling width of the suspension increases. Conversely, when a suspension is supplied in a fixed amount, the traveling speed of the suspension decreases as it approaches the discharge port, the residence time increases, and the time contributing to dispersion increases accordingly. Therefore, it can be said that as the suspension approaches the discharge port of the dispersion chamber, the residence time of the suspension increases and the shear rate of the media increases, so that the dispersion energy increases synergistically. In particular, this shape has the advantage of reducing overload during startup.

By using a media-type dispersion machine consisting of a rotor and a stator having the above-mentioned shape, it has excellent dispersion effect and can disperse fine particles without causing shot-pass phenomenon of coarse particles or blockage phenomenon due to concentration of media. A sharp dispersion with a uniform particle size distribution can be efficiently obtained. Further, since the stirring speed of the media is gradually increased, the stirring member is not strained and there is little wear and tear. Furthermore, since the media is also stirred by the stirring member, there is little direct wear on the outer wall of the rotor and the inner wall of the stator, and the device can withstand long-term use simply by replacing and installing the stirring member as necessary. Furthermore, by gradually increasing the force of crushing and dispersing in accordance with the particle size of the dispersed material, the dispersibility is superior to that of a product that is rapidly crushed and dispersed with a large force from the beginning. The gloss of the resulting dispersion, for example a printing ink or a paint, is improved.

FIG. 2 shows a preferred embodiment of the disperser according to the present invention. This shows a device in which the shape of the rotor is not only a simple inverted conical shape, but also a shape that is a combination of an inverted conical shape and a cylindrical shape on the upper part (hereinafter referred to as an inverted conical cylindrical shape).

In FIG. 2, the rotor has an inverted conical shape at a portion A on the suspension inlet side, and a cylindrical shape in a portion B on the discharge port side with the diameter being the maximum diameter of the inverted cone. With this shape, dispersion is performed in the inverted conical part while gradually increasing the stirring speed of the media as described above, and maximum stirring is performed in the final part of the inverted conical shape, and the next successive In the cylindrical part, the stirring is maintained for a while and then constant stirring is continued to further ensure dispersion. By adopting such a shape, the short pass phenomenon of coarse particles can be more reliably prevented.

Further, FIG. 3 shows a specific example in which a stirring member is also attached to the inner wall of the stator to effect more effective stirring of the media. Reference numeral 16 indicates a stirring member attached to the stator inner wall 11. Rotor stirring member 15
The rotor agitating members are mounted so as to face each other and to be located midway between the upper and lower adjacent ones of each rotor stirring member. Note that a similar stator stirring member can be attached to the above-mentioned dispersing machine (FIG. 1) consisting of an inverted conical rotor and stator. Furthermore, the corrugated protuberances 23 can be formed between the stator stirring members or at positions corresponding thereto. The details will be explained with reference to FIG.

Here, regarding the more specific sizes and shapes of the rotor stirring member 15 and the stator stirring member 16, the media can be stirred at a more stable shear rate,
In order to achieve more stable dispersion, those that satisfy the conditions described below are particularly preferred.

In other words, in the inverted cone-cylindrical dispersion machine shown in Figs. 2 and 3, the cylindrical part of the rotor is a part for more reliable dispersion, and this part has a more stable shear rate. It is preferable to provide a stirring member having a configuration that provides the following.

FIG. 4 is an enlarged view of a part of the cylindrical part of the device shown in FIG. 3, excluding the corrugated protuberances, and shows the relative relationship between the stator stirring member 16 and the rotor stirring member 15. . 22 indicates the central axis of the rotor. Here, the stirring member 16 fixed to the stator inner wall 11 is shown with a rectangular cross section. The lower contact point A between the stator stirring member 16-1 and the stator inner wall 11, the upper contact point B between the stator stirring member 16-2 and the stator inner wall 11, and the intersection of the horizontal line passing through A and B with the central axis 22. are respectively D and E,
If the midpoint between points A and B is C, a triangle ADC and a triangle BEC are formed.

During the crushing and dispersion operations, the stator inner wall 11 and stator stirring member 16 are fixed, and the rotor outer wall 12
The rotor stirring member 15 rotates around the rotating shaft 22 and forcibly stirs the media in the dispersion chamber. The angular velocity of the rotor is ω, the rotation axis 22
The length to the tip of the rotor stirring member is R ₂
Then, the circumferential speed V at the tip of the rotor stirring member is represented by ω·R ₂ . Here, if angle ADC and angle BEC of triangle ADC and triangle BEC are θ, the vertical distance between the tip of the rotor stirring member and the stator stirring member is expressed as R ₂ tan θ.

Shear rate between points N and O of the stator stirring member, which are perpendicular to the lower point P and upper point Q of the tip of the rotor stirring member
e ₃ is expressed as follows.

e ₃ =ω・R ₂ ／=ω・R ₂ ／=ω・R ₂ /
R ₂ tanθ=ω/tanθ.

The shear rate e ₄ between the center point M of the tip of the rotor stirring member and the horizontally corresponding point C on the inner wall of the stator is expressed as follows.

It is expressed as e ₄ =ω・R ₂ /, and if ==, then e ₄ =ω・R ₂ ／=ω・R ₂ ／=ω・R ₂ / =ω・R ₂ /R ₂ tanθ=ω/tanθ becomes.

Further, the horizontal distance between the outer wall of the rotor and the tip J or K of the stator stirring member is expressed by or, and if or is _R0 , the circumferential speed at the outer wall of the rotor is expressed by _ωR0 . here the interval
When FJ or is equal to the interval of or, the respective shear rates _e5 between points F and G on the outer wall of the rotor and points J and K at the tip of the stator stirring member are expressed as follows.

e ₅ =ω・R ₀ /(=)=ω・R ₀ /(=) =ω・R ₀ /R ₀ tanθ=ω/tanθ.

As explained above, the stator stirring member N is in a vertical relationship with the lower point P and upper point Q of the tip of the rotor stirring member.
the respective shear rates e ₃ between points M and O, the shear rates e ₄ between the tip center point M of the rotor stirring member and the horizontally corresponding point C on the stator inner wall, and the rotor outer wall points F and G. The respective shear velocities e ₅ between points J and K at the tip of the stator stirring member, which are in a horizontal relationship with the point, all show a constant value as ω/tanθ. Therefore, it is possible to achieve substantially uniform forced stirring of the media filled in the dispersion chamber, and the short pass phenomenon or partial aggregation of the media is less likely to occur.

The configuration of FIG. 4 can be summarized as follows.

The thickness of the stator and rotor stirring members are both d ₁ , the angles BEC and ADC are O<θ≦20°, and from the following equations (1), (2), and (3), θ and By determining R ₃ and R ₀ , the thickness d ₁ and length (R ₂ −R ₀ ) of the stirring member,
(R ₃ −R ₁ ) can be specified.

R ₀ + R ₀ tan θ = R ₁ (1) R ₂ + R ₂ tan θ = R ₃ (2) d ₁ = 2 × (R ₃ − R ₂ ) tan θ (3) Figure 5 shows the same purpose as Figure 4. Although it is a drawing,
More preferred specific examples of the size, shape, etc. of the rotor stirring member will be shown. That is, the shape of the rotor stirring member 15 is the hypotenuse of the triangle BEC and ADC,
It has a trapezoidal cross section (HIQP) that corresponds to CD.
Here, the distance between the center point M of the tip of the trapezoidal rotor stirring member and the horizontally corresponding point C on the stator inner wall = the upper point J of the tip of the stator stirring member.
and the distance between point F on the outer wall of the rotor that corresponds horizontally to this = Then, the distance, , and the shear rate between J and N, which correspond vertically to L to P, are both expressed as ω/tanθ, It becomes a constant value.

Furthermore, between the stator stirring members on the inner wall of the stator,
An example is shown in which the wave-shaped protuberances 23 are formed to form a semicircle whose radius is the MC or an interval close to the MC. By forming the wavy ridges, the distance between the tip of the rotor stirring member and the wavy ridges is constant, and the shear rate at any point on the wavy ridges is ω/tanθ. Therefore, more uniform stirring of the media is possible.

The configurations of both stirring members in FIG. 5 can be summarized as follows. Both the thickness of the rotor stirring member and the thickness of the stator stirring member at the vertical position of the tip of the stator stirring member are d ₂ , and the angle of the angle BEC and ADC is,
If 0<θ≦20° and the length (R ₃ − R ₂ ) is equal to the length (R ₂ − R ₁ ), then θ and R ₃ are calculated from the following equations (1), (2), and (3). By determining the thickness of the stirring member d ₂
(For rotor stirring members, this means the thickness at the position corresponding to the tip of the stator stirring member.), length (R ₂
−R ₀ ), (R ₃ −R ₁ ), and the rotor outer wall radius R ₀ can be specified.

R ₀ + R ₀ tan θ = R ₁ (1) R ₂ + R ₂ tan θ = R ₃ (2) d ₂ = 2 x (R ₃ - R ₁ ) tan θ = 4 x (R ₃ - R ₂ ) tan θ (3) This As a result, the surface areas of the rotor stirring member and the stator stirring member become approximately equal, allowing more uniform mixing of the media.

In addition, in the inverted conical part, a stirring member of the same size and shape as the stirring member of the cylindrical part shown in FIG. It is more preferable that the interval between the inner walls is also the same as that of the cylindrical part.

Although only cross-sectional views are shown in FIGS. 1 to 5, the stator and rotor stirring members may have a cylindrical pin shape, a conical pin shape, or a cross section as long as the above conditions are satisfied. It may be a disk type having these cross sections or a partially cut disk type. The tip side can take various shapes, such as rounded, flat, or variations thereof.

FIG. 6 is a cross-sectional view taken along the line A--A in FIG. 3, and is a cross-sectional view showing an example in which both stirring members are of a pin type.

Further, although FIG. 1 shows an example of how to attach the rotor, the method of attaching the rotor can be freely modified as necessary. Furthermore, by passing a refrigerant or the like through the rotor, more effective heat exchange is possible.

The dispersing machine of the present invention having the above configuration is as follows:
It can be used for pulverizing and dispersing suspensions made of various materials, and the following effects can be expected.

Since the stirring speed of the media in the dispersion chamber is gradually increased from the inlet of the suspension to the outlet, overload at startup is reduced, energy loss is small, and the stirring speed is adjusted to match the particle size of the dispersed material. Gradual pulverization and dispersion can be carried out, and stable dispersion can be achieved without causing partial aggregation or clogging of the media.

As the residence time of the suspension increases as dispersion progresses, more reliable dispersion is possible, the shot pass phenomenon is less likely to occur, and the particle size is fine.
Moreover, a dispersion with a sharp distribution can be obtained.

By using an inverted conical and cylindrical rotor, more reliable dispersion is possible in the cylindrical part.
Fine dispersions with a sharp particle size distribution are likewise obtained.

There is little local wear deformation or destruction of the stator inner wall, rotor outer wall, each stirring member, and media.

[Brief explanation of drawings]

FIG. 1 shows a longitudinal sectional view of a specific example of a continuous media type disperser. FIG. 2 shows a vertical cross-sectional view of a specific example of the continuous media type disperser according to the present invention, which has a shape in which a cylindrical rotor is combined with the upper part of the inverted conical rotor shown in FIG. FIG. 3 is a vertical cross-sectional view of a specific example of the continuous media type disperser according to the present invention, in which stirring members are also attached to the inner wall of the stator and corrugated protuberances are formed between the stirring members. FIG. 4 is an enlarged view of a part of the disperser shown in FIG. 3, showing the relative relationship between the rotor stirring member and the stator stirring member of the disperser (excluding the corrugated raised body). . FIG. 5 shows a more preferred embodiment for the same purpose as FIG. FIG. 6 is a cross-sectional view taken along line A-A in FIG. 3. 11... Stator inner wall, 12... Rotor outer wall, 1
3... Dispersion chamber, 14... Media, 15... Rotor stirring member, 16... Stator stirring member, 17...
Material inlet, 18...media separator, 19...discharge port, 20...medium passage, 23...corrugated raised body,
24...Medium passage.

Claims (1)

[Scope of Claims] 1. A dispersion chamber surrounded by the inner wall of the stator, the outer wall of the rotor, and a media separator, and the media filled in this dispersion chamber are forcibly stirred to continuously crush and disperse the suspension. In a continuous media type dispersion device consisting of a rotatably supported rotor with a rotor stirring member projecting radially toward the dispersion chamber, the rotor has an inverted conical upper part combined with a cylindrical shape. A continuous media type disperser with a stator inner wall having a shape corresponding to the shape of the rotor, and a constant interval between the rotor outer wall and the stator inner wall. 2. The continuous media type disperser according to claim 1, wherein a device for cooling or heating is provided inside the rotor or outside the stator. 3. A dispersion chamber surrounded by the inner wall of the stator, the outer wall of the rotor, and the media separator, and a radial chamber for continuously crushing and dispersing the suspension by forcibly stirring the media filled in this dispersion chamber. In a continuous media type dispersion device consisting of a rotatably supported rotor having a rotor stirring member protruding toward the dispersion chamber, the shape of the rotor is a combination of an inverted conical top and a cylindrical shape. The inner wall of the stator also has a shape corresponding to the shape of the rotor, the distance between the outer wall of the rotor and the inner wall of the stator is constant, and the inner wall of the stator faces the rotor stirring member, and the stator inner wall Continuous media type dispersion machine with a stator stirring member on top. 4 In the cylindrical part, position the rotor stirring member between the upper and lower sides of adjacent stirring members fixed to the inner wall of the stator, and connect the mounting contacts A and B of the stator stirring member.
A triangle connecting the intersection point D or E of the horizontal line passing through the point and the rotation axis of the rotor, and the midpoint C of points A and B.
The rotor stirring member is placed at a position corresponding to the triangular CIH formed by dividing the CDE by the rotor outer wall, and the distance between the tip of the rotor stirring member and the stator inner wall is adjusted so that the distance between the tip of the rotor stirring member and the stator stirring member is The continuous type according to claim 3, wherein the vertical spacing is equal to and the distance between the tip of the stator stirring member and the rotor outer wall is equal to the triangle BEC and ADC separated by the rotor outer wall. Media type disperser. 5 The rotor stirring member in the cylindrical part is shaped like a triangle.
A continuous media type disperser according to claim 3 or 4, which has a trapezoidal cross section in CDE (HIQP Fig. 5). 6 A patent in which a wave-shaped raised body (Fig. 5, 23) is provided between the stirring members on the inner wall of the stator, the radius of which is the length from the tip of the rotor stirring member to the inner wall of the stator, or an approximate distance thereto. A continuous media type disperser according to any one of claims 3 to 5. 7. The continuous media type disperser according to any one of claims 3 to 6, wherein a cooling or heating device is provided inside the rotor or outside the stator.