JPH06218296A - Pulverizing device having agitating mill - Google Patents

Abstract

PURPOSE:To provide the pulverizing device in which a slurry to be pulverized is circulated and passed to a pulverizing chamber and the agitating mill which is suitable for such a circulation type pulverizing device and does not concentrate the pulverizing medium circulated in the pulverizing chamber to one point. CONSTITUTION:The agitating mill 1 has a cylindrical vessel 2 and a hollow agitating shaft 4 which is disposed coaxially and freely rotatably in the vessel and is provided with agitating members 4a on its peripheral surface. The vessel is formed with a slurry inlet 6 at one end in its axial direction and a slurry outlet 7 at the other end. An inlet 12 for medium circulation is formed at the end of the agitating shaft and an outlet 13 for medium circulation is formed at the end of the hollow agitating shaft which is adjacent to the slurry inlet. A screen 8 is provided to enclose the slurry outlet. The pulverizing medium packed in the pulverizing chamber 11 is moved in the axial direction of the vessel by the circulating pressure of the slurry and is circulated in the vessel along the circulation route entering the inside of the agitating shaft from the inlet for the medium circulation of the agitating shaft and entering the inside of the pulverizing chamber from the outlet for medium circulation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulverizer used for finely pulverizing powder by wet pulverization or fine powder such as a pigment, and a stirring mill used for the pulverizer. Particularly, the present invention is characterized in that a grinding medium is filled in a grinding chamber between a container and a stirring shaft rotatably arranged in the container,
An agitating mill of a type adapted to rotate an agitating shaft while agitating a slurry to be ground in a grinding chamber to agitate a grinding medium to grind or disperse the object to be ground, or a grinding device using the agitating mill. Regarding

[0002]

2. Description of the Related Art Conventionally, a stirring mill used for this purpose has a structure in which a stirring shaft is axially arranged in a cylindrical container and stirring pins are radially attached to the stirring shaft.
The slurry inlet is provided at one axial end of the container, and the slurry outlet is provided at the other axial end of the container. A container is filled with a grinding medium such as glass beads, and a stirring pin is rotated by a stirring shaft while introducing the slurry from the slurry introduction port, and the slurry is passed between the grinding media to perform desired fine grinding and fine dispersion. The slurry flows in the axial direction of the container and is taken out from the slurry take-out port. A separating means such as a screen for separating the grinding medium from the slurry is provided at the slurry outlet.

In this conventional stirring mill, the ratio of the length to the inner diameter of the crushing chamber is 2.5 to 3.5 so that a sufficient crushing or dispersing effect can be achieved by passing the slurry to be crushed only once. Was set to. However, in the conventional structure,
During operation, the grinding medium tends to undergo centrifugal forces and concentrate radially outward. Therefore, a hollow portion in which the density of the grinding medium becomes sparse is generated inside the container in the radial direction, and a so-called bypass phenomenon in which the slurry passes through the hollow portion occurs,
The crushing or dispersing effect is reduced. Further, inside the crushing chamber, a flow occurs from the slurry inlet to the slurry outlet, so that the crushing medium tends to concentrate on the slurry outlet side due to the pressure of the flow, and the crushing chamber should be used effectively. However, there is a problem that the grinding medium is compressed and wear is increased. Further, most of the power for pulverization is consumed as agitation heat, so that there is a problem that the temperature rise of the slurry is large and the temperature control becomes difficult.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the problems that the grinding medium tends to concentrate in a part of the grinding chamber and that the temperature control is difficult in the conventional stirring mill. Is an issue.

[0005]

Means for Solving the Problems In order to solve the above problems, the present invention provides a crushing apparatus that can circulate a slurry to be crushed and pass it through a crushing chamber. Further, the present invention is
(EN) Provided is a stirring mill suitable for such a circulation type crushing device, in which a crushing medium is circulated in a crushing chamber so as not to concentrate on a part. The stirring mill according to the present invention comprises a cylindrical container and a hollow stirring shaft coaxially and rotatably arranged in the container and provided with a stirring member on the peripheral surface. In the container, a slurry inlet is formed adjacent to one axial end and a slurry outlet is formed adjacent the other end. A medium circulation inlet is formed at the end of the hollow stirring shaft adjacent to the slurry outlet of the container, and a medium circulation outlet is formed at the end of the hollow stirring shaft adjacent to the slurry inlet. A screen is provided around the slurry outlet, and the crushing medium filled in the crushing chamber formed between the inner surface of the container and the outer surface of the stirring shaft moves in the axial direction of the container due to the circulation pressure of the slurry to move the medium of the stirring shaft. It is circulated in the container through a circulation path that enters the stirring shaft from the circulation inlet and enters the grinding chamber from the medium circulation outlet of the stirring shaft.

The crushing apparatus according to the present invention uses the stirring mill having the above-mentioned structure. The discharge port of the slurry feeding pump is connected to the inlet of the stirring mill, and the suction port of the slurry feeding pump and the stirring mill. A slurry stirring tank is connected to the outlet. Then, the pulverized material slurry is sucked by the pump from the tank, sent to the stirring mill, and circulated from the stirring mill to the stirring tank.

[0007]

In the stirring mill according to the present invention, the slurry to be ground is introduced into the grinding chamber through the slurry inlet formed in the container. The grinding medium filled in the grinding chamber is stirred by the stirring shaft together with the slurry, and the object to be ground in the slurry is ground into fine particles by friction between the grinding media. The pulverizing medium is pushed in the direction of the outlet by the pressure of the slurry, but the pulverizing medium reaching near the outlet of the container enters the stirring shaft from the medium circulation inlet formed at the end of the hollow stirring shaft, and near the inlet of the container. It is returned from the medium circulation outlet to the grinding chamber. In this way, since the grinding medium circulates in the stirring mill, the grinding medium is prevented from concentrating on a part of the grinding chamber, and the grinding action effectively utilizing the entire grinding chamber can be achieved.

In the circulation type crushing apparatus of the present invention using such a stirring mill, the medium to be crushed, which has left the stirring mill, is returned to the tank and fed again to the stirring mill by the slurry feeding pump. . In this circulation path, it is easy to control the temperature of the slurry by means such as providing a cooling device.

[0009]

Embodiment An embodiment of the present invention will be described below with reference to the drawings. Referring to FIG. 1, a stirring mill 1 embodying the present invention
Has a cylindrical container 2, and a cooling jacket 3 is formed around the container 2. Cooling jacket 3
A cooling water inlet 3a is formed at the cooling water outlet 3b, and cooling water is circulated in the jacket 3. The container 2 has both ends of a cylinder closed by end plates 2a and 2b.
A cylindrical wall 2c is provided between b. A stirring shaft 4 is arranged in the container 2. The stirring shaft 4 has a cup shape with one end open and the other end closed, and a drive shaft 5 extends axially outward from the closed end. Stirring shaft 4
Is arranged coaxially with the container 2 and the drive shaft 5 penetrates the end wall 2 a of the container 2 and projects to the outside of the container 2.

In the container 2, a slurry inlet 6 for introducing the slurry to be ground is formed in an end plate 2a adjacent to the closed end of the stirring shaft 4, and a slurry outlet is formed in the center of the opposite end plate 2b. 7 are formed. A cylindrical screen 8 is provided in the container 2 so as to surround the slurry outlet 7. The screen 8 is inserted into the agitation shaft 4 from the open end of the agitation shaft 4. Screen 8 and stirring shaft 4
A gap is formed between the opening of the end portion and the crushing medium so that the grinding medium can flow. This gap constitutes the medium circulation inlet 12. On the stirring shaft 4, at a position adjacent to the closed end,
A plurality of grinding medium circulation outlets 13 are formed at intervals in the circumferential direction.

A large number of radially stirring members 4a are provided on the outer circumference of the stirring shaft 4. The stirring shaft 4 is the drive shaft 5
It is rotationally driven by driving the pulley 9 provided in the above with a motor via a belt 10. An annular grinding chamber 11 is provided between the inner surface of the cylindrical wall 2c of the container 2 and the outer surface of the stirring shaft 4.
Is formed. The grinding chamber 11 is filled with a grinding medium 15 such as glass beads. The grinding chamber 11 is preferably dimensioned such that the ratio of axial length to inner diameter is not greater than 1.7. Further, the ratio of the outer diameter of the screen 8 to the inner diameter of the crushing chamber 11 is preferably set larger than 0.3.

A slurry tank 19 is provided in addition to the stirring mill 1. The slurry tank 19 has a motor 16
The stirring blade 17 driven by is arranged. The slurry outlet 7 provided in the container 2 of the stirring mill 1 is connected to this slurry tank 19. Further, the slurry outlet 19 a provided at the lower end of the slurry tank 19 is connected to the suction port 18 a of the slurry feed pump 18. The discharge port 18b of the slurry feed pump 18 is the container 2 of the stirring mill 1.
It is connected to the slurry inlet 6 provided in.

Referring to FIG. 3, the medium circulation outlet 13 of the stirring shaft 4 is inclined radially outward with respect to the rotation direction of the stirring shaft 4 shown by an arrow A, in the direction opposite to the rotation direction. It is formed. Due to this inclination, when the stirring shaft rotates in the direction of arrow A, the grinding medium 15 inside the stirring shaft 4
Is sucked into the crushing chamber 11 from the medium circulation outlet 13.

The operation of the illustrated embodiment of the invention will now be described. The slurry feeding pump 18 is operated to supply the slurry to be ground to the grinding chamber 11 of the stirring mill 1 while the stirring shaft 4
To rotate. The crushing medium 15 in the crushing chamber 11 is agitated by the agitating member 4a of the agitating shaft 4, and the pulverized material slurry circulates between them to pulverize the pulverized material. The slurry to be ground that has passed through the grinding chamber 11 of the stirring mill 1 is separated from the grinding medium 15 by the screen 8 at the slurry outlet 7 and sent to the stirring tank 19.
In the stirring tank 19, the stirring blade 17 driven by the motor 16 stirs the slurry.

The slurry from the stirring tank 19 is sent to the stirring mill 1 again by the feed pump 18 and further pulverized. In this way, fine grinding of the material to be ground by continuous circulation is achieved. Since the slurry to be ground is sent to the stirring mill 1 by the feed pump 18, the pressure of the sending tends to push the grinding medium 15 together with the slurry toward the outlet 7. The grinding medium 15 pushed to the outlet 7 side enters the inside of the stirring shaft 4 from the medium circulation inlet 12. Then, the grinding medium 1 inside the stirring shaft 4
5 is returned from the circulation outlet 13 to the crushing chamber 11 on the slurry inlet side. In this way, the crushing medium 15 is circulated from the crushing chamber 11 back to the crushing chamber via the stirring shaft 4, so that the problem that the crushing medium 15 is concentrated near the outlet of the crushing chamber 11 can be solved. As shown in FIG. 4, the slurry outlet 7 of the stirring mill 1 is changed over to the switching valve 2
By connecting to the product tank 21 through 0, the crushed slurry can be taken out to the tank 21.

[0016]

As described above, in the present invention, since the stirring mill is configured so that the grinding medium in the grinding chamber circulates through the inside of the stirring shaft, the grinding medium is concentrated near the outlet of the grinding chamber. The pressure loss is reduced, and the crushing chamber can be effectively used to perform the crushing. Also,
Since the stirring mill is connected to the circulation path including the stirring tank and the feeding pump, it is possible to perform continuous circulation type fine pulverization and increase the degree of pulverization.

[Brief description of drawings]

FIG. 1 is a schematic view of a crushing device showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line I-I in FIG.

FIG. 3 is an enlarged sectional view of a stirring shaft used in an embodiment of the present invention.

FIG. 4 is a diagram schematically showing an entire embodiment of the present invention.

[Explanation of symbols]

1 ... Stirring mill, 2 ... Container, 3 ... Cooling jacket,
4 ... Stirring shaft, 5 ... Drive shaft, 6 ... Slurry inlet, 7
... Slurry outlet, 8 ... Screen, 11 ... Grinding chamber, 12 ... Medium circulation inlet, 13 ... Medium circulation outlet, 18 ... Feed pump , 19 ... ・ Stirring tank.

Claims (10)

[Claims] 1. A stirring mill which is filled with a grinding medium and which circulates a slurry of an object to be ground while stirring the grinding medium to carry out grinding, and a discharge port is connected to the entrance of the stirring mill. And a slurry stirring tank connected to the suction port of the slurry feeding pump and the outlet of the stirring mill. The slurry to be ground is sucked from the tank by the pump and stirred. In a crushing device having a stirring mill, which is sent to a mill and circulated from the stirring mill to the stirring tank, the stirring mill includes a cylindrical container and a circular container rotatably and coaxially arranged in the container. And a hollow stirring shaft provided with a stirring member on the surface, the medium circulation inlet at the end of the hollow stirring shaft adjacent to the slurry outlet of the stirring mill, A medium circulation outlet is formed at an end of the hollow stirring shaft adjacent to the slurry inlet of the stirring mill, and a screen is provided to surround the slurry outlet of the stirring mill, and the inner surface of the container and the stirring shaft are provided. The grinding medium filled in the grinding chamber formed between the stirring shaft and the outer surface of the stirring shaft moves in the axial direction of the container due to the circulation pressure of the slurry, and enters the stirring shaft from the medium circulation inlet of the stirring shaft. A crushing device having a stirring mill, characterized in that it is circulated in the stirring mill by a circulation path entering from the medium circulation outlet into the crushing chamber. 2. A cylindrical container, and a hollow stirring shaft coaxially and rotatably arranged in the container and provided with a stirring member on a peripheral surface thereof. The container is adjacent to one axial end thereof. Slurry inlet, slurry outlet is formed adjacent to the other end, respectively, the medium circulation inlet at the end of the hollow stirring shaft adjacent to the slurry outlet of the container,
A medium circulation outlet is formed at an end of the hollow stirring shaft adjacent to the slurry inlet, and a screen is provided so as to surround the slurry outlet, and is formed between an inner surface of the container and an outer surface of the stirring shaft. The crushing medium filled in the crushing chamber is moved in the axial direction of the container by the circulation pressure of the slurry and enters the stirring shaft from the medium circulation inlet of the stirring shaft to the medium circulation outlet of the stirring shaft. An agitating mill, characterized in that it is circulated in the container by a circulation path entering the crushing chamber. 3. The crushing device according to claim 1 or the stirring mill according to claim 2, wherein the medium circulation inlet is formed by an opening at an axial end of the stirring shaft. , Pulverizer or stirring mill. 4. The crushing device according to claim 1, the stirring mill according to claim 2, or the crushing device or stirring mill according to claim 3, wherein the medium circulation outlet is
A crushing device or a stirring mill, which is formed by a plurality of openings formed at intervals in the circumferential direction on the peripheral surface of the stirring shaft. 5. The crushing apparatus or the agitation mill according to claim 4, wherein the plurality of openings formed in the peripheral surface of the agitation shaft is used to pulverize the medium in the agitation shaft as the agitation shaft rotates. A crushing device or a stirring mill, characterized in that the circumferential side edge surface is inclined so as to be discharged into the chamber. 6. The crushing device or the stirring mill according to claim 3, wherein the screen is disposed adjacent to an opening of the axial end of the stirring shaft.
Grinding device or stirring mill. 7. The crushing apparatus according to claim 1, the stirring mill according to claim 2, or the crushing apparatus or stirring mill according to any one of claims 3 to 6, wherein a shaft of the crushing chamber Grinding device or stirring mill, characterized in that the ratio of the directional length to the inner diameter is not greater than 1.7. 8. The crushing device according to claim 1, the stirring mill according to claim 2, or the crushing device or stirring mill according to any one of claims 3 to 7, wherein the screen has a cylindrical shape. And the ratio of the outer diameter of the screen to the inner diameter of the crushing chamber is larger than 0.3. 9. The crushing apparatus or the stirring mill according to claim 6, wherein the screen is a cylindrical screen, and one end of the cylindrical screen is inserted into an opening of the axial end of the stirring shaft. A crushing device or a stirring mill, characterized in that 10. The grinding device according to claim 1, the stirring mill according to claim 2, or the grinding device or stirring mill according to any one of claims 3 to 9, wherein the circumference of the stirring shaft is A crushing device or a stirring mill, characterized in that a stirring member protruding radially is provided on the surface.