JPH04326934A - Dispersion device - Google Patents

Abstract

PURPOSE:To prevent such a phenomenon that undispersed solid particles are bonded to the inner wall of a tank or a part of a mill base is stagnated at the corners of the tank in a basket mill constituted by arranging a basket having a dispersing medium of beads received therein in the tank and circulating the solid particle suspension present in the tank to the basket and dispersing the suspension in a colloidal form. CONSTITUTION:The scraper 8 relatively moving along the inner wall surface of a tank 1 to scrape off the bonded matter on the inner wall surface of the tank is provided separately from a basket 4.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention relates to a device for colloidally dispersing solid particle suspensions such as paints and inks, and in particular to dispersion processing in a tank containing a mill base, which is a solid particle suspension. This relates to a type of dispersion device called a bucket mill in which a basket is placed for performing the following steps.

0002

BACKGROUND OF THE INVENTION Media-type dispersion agitators have conventionally been used to produce paints, inks, and the like. A media-type dispersion stirrer is a device that uses a medium such as sand, hard glass beads, or steel balls to forcibly stir and disperse a mill base, which is a suspension of solid particles such as pigments. Sand mills, ball mills, and attritors are well known.

[0003] A sand mill is one that mainly uses sand or hard glass beads as a dispersion medium.
The premixed mill base is pumped into a tank and forced to flow by stirring blades located inside the tank, thereby dispersing the aggregates in the mill base. The mill base with solid particles dispersed therein is sequentially taken out of the machine, and new mill base is supplied into the tank. This is a so-called continuous processing type dispersing machine. On the other hand, ball mills and attritors mainly use steel balls as the dispersion medium, and solid particles and liquid are put into a tank and stirred and mixed each time.They are so-called batch processing type dispersion agitators. .

[0004] In recent years, a dispersing machine called a so-called basket mill using a cage has been developed (for example,
Publication No. 6687). This disperser has a cage containing a medium attached to a mill base in a tank, and uses stirring blades placed inside the cage to forcibly flow the medium inside the cage, and a convection blade placed directly below the cage to force the medium to flow. By forcing the mill base in the tank into the cage, the mill base in the tank flows in from the upper part of the cage and flows out from the lower part. In order to eliminate the drawbacks of basket mills that use cages, the present inventors have invented a basket mill that uses a vessel having a small hollow chamber in place of the cage (Japanese Patent Application No. 177144/1999). In addition, in this application, the cage body and vessel arranged in a tank are collectively called a basket.

[0005]

[Problems to be Solved by the Invention] Although sand mills have a large processing capacity because they perform continuous processing, they also require stirring and mixing (premixing) of solid particles and liquid in advance, and when the work is finished, When changing the processing material, there is a drawback that it requires a great deal of effort to clean the pump for pumping the mill base and other parts. In addition, in ball mills and attritors, pretreatment of the mill base is not necessary, but since the tank itself serves as a dispersion chamber, the amount of medium filled therein increases. Therefore, a large amount of liquid remains in the gaps between the media, resulting in extremely poor cleaning performance at the end of work or when changing the material to be treated.

[0006] On the other hand, although the above-mentioned drawbacks are solved in the basket mill, it has been found that there is a problem in ensuring that the mill base in the tank is circulated into the basket. In particular, when the material to be treated is a high viscosity paint or a paint with high thixotropy, the convection is weak and solid particles may adhere to the inner wall of the tank in an undispersed state as shown by A in Figure 15, or some mill base It was found that there is a possibility that the water may remain in the tank without being circulated. This not only reduces the dispersion processing efficiency of the mill base and prevents reliable dispersion processing, but also prevents heat conduction from the jacket when the tank is jacketed and the dispersion processing temperature is constant, causing the temperature inside the tank to decrease. There is a risk that the temperature will rise and you will be unable to drive. In view of these points, the present invention has devised a basket-type dispersion device that can efficiently carry out dispersion treatment without undispersed mill base adhering to or remaining in the tank.

[0007]

[Means for Solving the Problems] A basket 4 containing a dispersion medium and dispersing the mill base contained therein is arranged in a tank 1 in which a mill base, which is a solid particle suspension, is accommodated. The mill base in the tank 1 is circulated through the basket 4, and the entire mill base in the tank is distributed. Inside the tank 1, apart from the basket 4, a scraper 8 is provided which rotates along the inner wall of the tank and scrapes off things adhering to the inner wall of the tank. The rotation of the scraper along the inner wall of the tank is relative, and the scraper 8 may be fixed and the tank 1 may be rotated. It is preferable that the scraper 8 maintains an outward facing angle with respect to the tangential direction, that is, the flow in the circumferential direction of the mill base in the tank 1, and is rotatably supported by a fixed angle on the scraper arm 18, which is its supporting means. . In addition, the basket 4 is not only located in the center of the tank 1;
It is more effective if the scraper 8 is positioned in a direction opposite to the orbit of the basket 4 while revolving inside the tank 1, and rotates around the center of the tank 1 as the center of rotation.

[0008]

[Operation] The mill base in the tank flows into the basket 4 located in the tank 1, the inflow mill base is dispersed by the medium in the basket 4 and flows out of the basket, and new mill base flows into the basket 4. Inflow. The millbase in the tank, which is thus a suspension of solid particles, is circulated through the basket and thereby colloidally dispersed throughout. When the scraper 8 rotates along the inner wall of the tank 1, it forcibly scrapes off solid particles adhering to the inner wall of the tank, or stirs the remaining mill base to make the mill base outside the basket as uniform as possible throughout the tank. do. In other words,
The scraper 8 performs two functions: scraping off deposits adhering to the inner wall surface of the tank and stirring the mill base inside the tank.

The mill base in the tank 1 generates a vertical flow due to convection into the basket, as shown by the arrows in FIGS. 5 and 6, and also by the rotation of the stirring blades 11, as shown by the white arrows in FIGS. 11 and 12. Circumferential flow also occurs as shown in . Therefore, if the scraper 8 is pivoted to the scraper arm 18, which is its support means, so as to be rotatable at a certain angle, and maintained at an angle facing outward with respect to the flow of the mill base, the mill base can be moved without applying excessive force. The scraper is pressed against the inner wall of the tank due to the flow resistance, and the deposits are scraped off.

In the case where the basket 4 inside the tank 1 revolves, the flow of the mill base inside the tank 1 becomes complicated, and the scraper 8 is placed in a wide space where stagnation is likely to occur.
The mill base inside the tank will be thoroughly stirred.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the accompanying drawings. Figure 1 uses a basket with a large number of small holes in either or both of the side walls and bottom, allowing the mill base to pass through but not the dispersion medium. An example of the positioning is shown. The tank 1 that accommodates the mill base, which is the material to be treated, has a cylindrical shape, for example, and has a jacket 2 attached to its outer surface so that the temperature inside the tank can be maintained constant by passing cooling water or a heat medium. I have to. The mill base accommodated in the tank is taken out by means of the valve 3 at the bottom.

A basket 4 made of a cage body is provided in the center of the tank 1 and can be taken in and out from above the tank. That is, the main body 5 is arranged adjacent to the tank 1,
The main body 5 has an arm 6 whose intermediate portion is supported and which moves up and down.
A basket 4 is provided at one end of the arm 6 and supported downwardly. That is, by raising and lowering the entire arm, the basket 4 can be taken in and out from above the tank, and the arm 6 can be rotated in a plane. A motor 7 is attached to the other end of the arm 6, and a power transmission means within the arm 6 transmits rotational force to the stirring blades inside the cage. Separate from the basket 4, a scraper 8 that rotates along the inner wall of the tank is provided at one end of the arm 6. Although the rotational axis of the stirring blade inside the cage and the rotational axis of the scraper are concentric, the rotation of the scraper is slower than the rotation of the stirring blade. As shown in FIG. 5, the cage body 9 is supported by the arm 6 by a support rod 10, and the stirring blades 11 inside the cage are rotationally driven by a drive shaft 12. The lower end of the drive shaft 12 extends below the cage and is provided with a convection blade 13, whereby the mill base inside the tank 1 is circulated through the cage as shown by the arrow.

A structure for attaching the basket 4 and arm 6 of the embodiment shown in FIG. 1 is shown in FIG. A cylindrical fixed base 14 is fixed downward to one end of the arm 6, and a basket support cylinder 17 is provided inside the base to be rotatable via bearings 15 and 16, and a basket support rod 10 is attached to the lower end of the base. Fixed. Furthermore, the basket support cylinder 17 has a scraper arm 18 that supports the scraper.
is fixed. A stirring blade drive shaft 12 is supported at the center of the cage support tube 17 via bearings 19 and 20.
The basket support tube 17 is independently rotated by a sprocket 21 attached to its upper end, and the drive shaft 12 is independently rotated by a pulley 22. That is, the cage body 9, which is a basket, may not rotate, but in this embodiment, it rotates in the same way as the scraper 8, and the stirring blades inside rotate separately from the cage body. However, the rotational speed of the scraper is much smaller than the rotational speed of the stirring blade.

In FIG. 2, the tank 1 is slowly rotated by a motor 23, and the scraper arm 18 is removed from the main body 5.
This figure shows an embodiment in which a scraper is provided at a position along the inner wall of the tank. That is, the scraper 8 is fixed, and as the tank 1 rotates, the scraper 8 scrapes off the deposits on the inner wall of the tank.

FIG. 3 shows an embodiment in which a cage body 9, which is a basket, is supported eccentrically from the center of the tank and is allowed to revolve within the tank. In this embodiment, a main body 5 is provided adjacent to the tank 1, and an arm 6 provided on the main body.
This embodiment is similar to the embodiment shown in FIG. 1 in that one end supports a cage body 9, which is a basket, and a motor 7 is provided at the other end of the arm 6, and a belt or chain passing through the arm drives the stirring blade. .

The attachment structure of the basket 4 and arm 6 of the embodiment shown in FIG. 3 is shown in FIG. A cylindrical fixed base 14 is fixed to one end of the arm 6, and a rotary cylinder 2 is connected to the inside of the base 14 via bearings 15 and 16.
4 is provided, and a bearing 19 is provided in the center of the rotating cylinder 24.
, 20 to the drive shaft 25 of the stirring blade located inside the basket.
is provided. A pulley box 26 is fixed to the lower end of the rotary cylinder 24, and the lower end of the drive shaft 25 passes through the pulley box. A sprocket 27 is attached to the upper end of the rotary cylinder 24 and is rotationally driven by a power transmission means (not shown). Further, a pulley 28 is provided at the upper end of the drive shaft 25 and is driven to rotate at a rotation speed different from that of the rotating cylinder 24 .

A basket is fixed to the pulley box 26 on one side (right side in the drawing) that is a certain distance away from the center of rotation, and a scraper arm 18 is fixed on the other side (left side in the drawing). To explain the fixing structure of the basket, a cylindrical boss 29 is fixed to the lower surface of the pulley box 26, and the support rod 10 of the basket is fixed to this. On the other hand, the drive shaft 12 of the stirring blade passes through the center of the boss 29 and reaches inside the pulley box, and a pulley 31 is fixed to the upper end. A belt is wound around a pulley 30 attached to the lower end of the drive shaft 25, and the rotation of the drive shaft 25 is controlled by the drive shaft 1 of the stirring blade.
I am telling 2. In other words, in the embodiment shown in FIG.
The basket revolves around the radius of the distance between the drive shafts 25 and 12, and the scraper 8 rotates around the drive shaft 25.

In the embodiment shown in FIG. 2, the tank 1 rotates. Therefore, if the basket 4 is placed in the center of the tank, as in the embodiment shown in FIG. 1, if the basket 4 is placed off-center, the basket will revolve inside the tank, as in the example shown in FIG. It will function in the same way.

FIG. 4 shows an embodiment in which a vessel 32 having a hollow chamber is used as the basket, and the difference from the embodiment shown in FIG. 1 is that the basket is a basket body 9 or a vessel 32. Therefore, for the power transmission mechanism, the drive mechanism for the stirring blades of the basket, etc., the structure shown in FIG. 9 is applied as is to the structure for attaching the basket 4 and arm 6 of the embodiment of FIG. 4.

Next, a method using a vessel as a basket will be explained with reference to FIG. The vessel 32 includes a vessel main body 32a and a rotor 32b. Support rod 1
The main body 32a of the vessel supported by the main body 32a is hollow with an open lower end, and a hole 33 is bored in the center of the top wall. The rotationally driven drive shaft 12 passes through the hole 33 and reaches the inside of the vessel main body, and a rotor 32b is attached to the tip of the drive shaft 12. A rotor 32b is attached to the tip of the drive shaft 12, and a dispersion medium is used as a dispersion medium between the lower surface of the vessel main body 32a and the rotor 32b. A small gap t that allows only the mill base to pass through, without allowing media such as glass beads to pass through.
is retained. A dispersion medium is inserted inside the vessel body, and when the rotor is rotated in the tank 1 filled with the mill base, a hole 33 drilled in the top wall of the vessel body is opened as shown by the arrow in FIG. The mill base flows into the vessel, the mill base dispersed in the vessel passes through the gap t, and is separated from the medium, and only the dispersed mill base flows back into the tank.

A modified embodiment of the specific structure of the vessel is shown in FIGS. 7 and 8. The vessel 32 shown in FIG. 6 has a rounded hollow chamber inside the vessel body so that the mill base flowing in from the hole 33 circulates inside, and when combined with the rotor, an annular dispersion chamber is formed. The mill base is circulated and discharged from the gap t by the centrifugal force generated by the rotation of the mill base. In the vessel 32 of the embodiment shown in FIG. 7, a hollow chamber with a straight cross section is formed, and a rod-shaped stirring blade 11 is fixed to the drive shaft itself. In the casel 32 of the embodiment shown in FIG. 8, an inverted truncated cone-shaped space that becomes narrower at the bottom is formed inside the bezel main body.
Discharge vanes 34 are provided on the outer periphery of the rotor. This discharge vane 34 promotes circulation of the mill base inside the vessel body.

In the case where the basket 4 is located at the center of the tank 1 as in the embodiment shown in FIG. 1, FIG. 2 or FIG.
As shown in Fig. 1, an even space is formed around the entire outer circumference of the basket, and a scraper is placed in a part of the space. However, in the case where the basket revolves within the tank as in the embodiment shown in FIG. 3, the space where the scraper is not located becomes narrow. Therefore, the possibility that the mill base remains in the tank is reduced, and a large space can be secured for arranging the scraper, making it possible to use a basket that is somewhat large compared to the size of the tank.

The scraper 8 may be pressed against the inner wall of the tank by, for example, a spring, but if it is moved toward the flow of the mill base as shown in FIGS. Can be pressed against a wall. This structure will be explained with reference to FIGS. 13 and 14. A cylindrical bearing 35 is fixed to the tip of the scraper arm 18, and a shaft 36 of the scraper 8 is supported thereon. A window hole 37 is bored in the cylindrical bearing 35 as a long hole in the circumferential direction over a certain angle range, and
A stopper 38 is screwed onto the shaft 36 so as to be positioned within the window hole 37. Therefore, the scraper 8 has a window hole 37 which is a long hole.
It can be rotated freely within the range. In other words, the scraper can be rotated outward without facing inward to the flow of the mill base, and the stopper can be brought into contact with the inner wall of the tank.

[0024]

According to the dispersion device of the present invention as set forth in claim 1, when dispersing a millbase, which is a suspension of solid particles, using a dispersion machine called a basket mill, even if it is a highly viscous or Even if it is highly thixotropic,
It is possible to prevent solid particles from adhering to the inner wall surface of the tank in an undispersed state, and to perform dispersion processing efficiently. This means that even if the tank is of a jacket type, the adhesion of solid particles will not impede heat conduction on the tank wall surface and will not impede operation.

According to the invention as claimed in claim 2, it is possible to prevent solid particles from adhering to the inner wall surface of the tank as in the invention as claimed in claim 1, and for example, the arm supporting the basket can be rotated in a plane. By moving the basket, it is possible to move the basket to any position within the tank and select a preferred basket position depending on the type of material to be processed.

According to the third aspect of the present invention, when scraping off deposits on the inner wall of the tank with the scraper, the inner wall of the tank is not pressed with excessive force and damaged. The higher the viscosity and the easier the solid particles adhere to the wall surface, the more force can be used to scrape off the solid particles.

According to the fourth aspect of the invention, it is possible to eliminate dead spots in the tank, that is, areas where mill base accumulates, and to further enhance the agitation effect in the tank, and to make the installation space of the scraper as wide as possible so that the relative Therefore, it is possible to use a basket that is relatively large compared to the size of the tank.

[Brief explanation of the drawing]

FIG. 1 is an overall front view showing a first embodiment of the present invention;

[
FIG. 2 is an overall front view showing a second embodiment of the present invention;

FIG. 3 is an overall front view showing a third embodiment of the present invention;

[Figure 4
] Overall front view showing the fourth embodiment of the present invention,

[Figure 5]
A vertical sectional view of a tank showing the flow of the mill base during dispersion work by a basket mill using a cage body,

[Fig. 6] A vertical cross-sectional view of a tank showing the flow of the mill base during dispersion work by a basket mill using a vessel.

FIG. 7 is a vertical cross-sectional view showing an example of a vessel;

FIG. 8 is a vertical cross-sectional view showing another example of the vessel;

FIG. 9 is a longitudinal sectional view showing the attachment structure of the main body arm and the basket in an embodiment in which the center of the basket and the rotation center of the scraper coincide and the basket is located at the center of the tank;

FIG. 10 is a longitudinal cross-sectional view showing the attachment structure of the main body arm and the basket in an embodiment in which the basket revolves around the center of the tank;

FIG. 11 is a cross-sectional view of the tank in an embodiment where the basket is located in the center of the tank;

FIG. 12 is a cross-sectional view of the tank in an embodiment in which the basket revolves within the tank;

FIG. 13 is a perspective view showing the attachment part of the scraper;

[
Figure 14: Cross-sectional view of the scraper mounting shaft,

[Figure 1
5] A vertical sectional view of a tank showing an example of a conventional basket mill.

[Explanation of symbols]

1 Tank 4 Basket 5 Main body 6 Arm 8 Scraper 9 Cage body 10 Support rod 12 Drive shaft 18 Scraper arm 26 Pulley box 32 Bethel 35 Bearing 36 axis 37 Window hole 38 Stopper

Claims (4)

[Claims] Claim 1: A basket 4 is disposed in a tank 1 that accommodates a mill base, a dispersion medium is housed in the basket 4, and the mill base in the basket is dispersed by stirring inside the dispersion medium. A dispersing machine for dispersing the mill base throughout the tank by circulating the mill base inside the basket, is characterized by being provided with a scraper 8 that rotates along the inner wall of the tank 1 and scrapes off deposits on the inner wall of the tank. Dispersion device. 2. A basket 4 is disposed in a tank 1 that accommodates the mill base, and a dispersion medium is housed in the basket 4 and the mill base in the basket is dispersed by stirring inside the dispersion medium. In a dispersing machine that circulates the mill base inside the tank through a basket to disperse the mill base throughout the tank, a fixed scraper 8 is placed along the inner wall of the tank 1 to scrape off deposits on the inner wall of the tank. A dispersion device characterized by rotating. 3. The scraper 8 located along the inner wall of the tank 1 maintains an outward facing angle from the tangential direction, and is pivotably supported to be rotatable within a certain angle range with respect to a scraper arm 18 supporting the scraper 8. The dispersion device according to claim 1 or claim 2, wherein the dispersion device is made of: 4. The dispersion according to claim 1, wherein the basket 4 is revolved within the tank 1, and the scraper 8 is positioned in a direction opposite to the orbit of the basket 4, and is rotated about the center of the tank. Device.