JPH0671560B2 - mill - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a mill such as a ball mill or a rod mill, and more particularly to a mill having an improved powder or granular material transfer mechanism such as a partition of a multi-chamber mill. .

[Prior Art] As a multi-chamber multi-chamber ball mill, for example, a ball mill in which the inside of the mill is divided into a coarse pulverization chamber and a fine pulverization chamber to perform two-stage pulverization is widely used. In the coarse crushing chamber of this two-stage crushing type ball mill, coarse crushing is performed with large diameter balls, and in the fine crushing chamber, fine crushing is performed with small diameter balls.

Such a ball mill (also referred to as a multi-chamber mill or a tube mill) divides the coarse crushing chamber and the fine crushing chamber, so that the coarse crushing chamber side eye plate (also called a great partition plate) is used. ) And a blind plate on the side of the fine crushing chamber and a cylindrical or polygonal cylindrical surrounding plate arranged on the side of the mill axis are provided inside the mill. This eye plate is, for example, 6 mm
It has a slit of a certain width. In addition, this reservoir chamber is divided into a plurality of small chambers by a raking plate extending in the radial direction of the mill.

In a ball mill that has been conventionally used, an opening for discharging the raw material in the small chamber to the fine crushing chamber is provided between the blind plate and the surrounding plate. Then, the raw material roughly crushed in the coarse crushing chamber enters the reservoir chamber (small chamber) through the slit of the eye plate and is scraped up by the scraping plate as the mill rotates. When the small chamber comes to a position above the axis of the mill, the raw material in the small chamber falls in the small chamber, passes through the opening between the blind plate and the surrounding plate, and is sent to the fine grinding chamber.

In addition, in Japanese Examined Patent Publication No. 58-9702, an annular chamber defined by an eye plate, a blind plate, and a surrounding plate is provided, and a half-cylindrical scoop is passed through the surrounding plate to adjust the twist angle of the scoop. By doing so, the discharge rate of the granular material from the annular chamber is adjusted.

[Problems to be Solved by the Invention] Since large-diameter balls are used in the coarse crushing chamber, the flow of the raw material is good, and the powder between the blind plate and the shroud is the same as in the former (a ball mill that has been conventionally adopted). If it is a partition of a mechanism that has an opening for discharging granules, when the small chamber is positioned above the axis by the rotation of the mill, the raw material falls and is sent to the fine pulverization chamber. Disappear. When the small chamber is positioned below the axis again by the rotation of the mill, the powder particles flow into the small chamber. When the mill continues to rotate, the granular material is continuously sent from the coarse grinding chamber to the fine grinding chamber in this manner. Therefore,
If the feed amount of raw material into the coarse crushing chamber decreases, the level of raw material to be crushed in the coarse crushing chamber becomes lower than the level of the balls. This causes hitting of the ball, resulting in energy loss and chipping of the back plate and the ball.

It should be noted that a measure to reduce the slit width of the eye plate to reduce the amount of the granular material raw material flowing into the reservoir chamber from the coarse crushing chamber is conceivable. Therefore, stable mill operation is difficult. Further, as another measure, it is conceivable to lower the ball level in the coarse crushing chamber according to the lowering of the raw material level, but with this, the crushing capacity is lowered.

On the other hand, in the method proposed in Japanese Examined Patent Publication No. 58-9702, the amount of the granular material to be fed from the annular chamber to the fine crushing chamber can be adjusted, so that the above problems can be solved to some extent. However, in this Japanese Examined Patent Publication No. 58-9702, the powder and granules are scraped up by a scoop and transferred from the annular chamber to the fine crushing chamber, so the load on the mill increases and a large amount of material to be pulverized flows into the annular chamber. In that case, the level of powder or granules in the annular chamber may increase, and the raw material level in the coarse crushing chamber may become excessive. Conversely, the mill load drops during operation,
Even if the amount of powder or granules flowing from the coarse crushing chamber to the annular chamber is small, a predetermined amount of powder or granular material is sent from the annular chamber to the fine pulverizing chamber, and the level of powder or granular material in the annular chamber is considerably lowered. However, along with this, there is a possibility that the raw material level in the coarse crushing chamber will fall below the ball level.

[Means for Solving the Problems] The mill of the present invention is a blind plate provided in an annular shape along the inner peripheral wall of the mill, and a blind plate provided at a predetermined distance from the blind plate in the axial direction of the mill. And a reservoir for powder and granules defined by an enclosing plate that is circumferentially provided on the mill axial center side between the eye plate and the blind plate. A plurality of scraping plates are arranged in the accumulating chamber in a direction including the radial direction of the mill, and the scraping plate divides the accumulating chamber into a plurality of small chambers. Then, in order to discharge the granular material from each small chamber, the pipe is installed so as to penetrate the surrounding plate and have its tip protruding into the small chamber. The tip of this pipe is an opening.

When the small chamber occupies a position vertically above the axis of the mill, the length of projection of this pipe into the small chamber substantially matches the retention height of the granular material in the small chamber which occupies the vertical position. The length is such that the granular material in the small chamber can flow into the pipe only through the opening at the tip.

[Operation] In the mill of the present invention, when the small chamber is located above the axial center due to the rotation of the mill, the level of the raw material accumulated in the small chamber which is not fed to the pulverization chamber is almost equal to the protruding length of the pipe into the small chamber. To do. When the small chamber is located below, the stagnant raw material in the small chamber raises the position where the raw material flows into the small chamber from the coarse crushing chamber, and the raw material level in the coarse crushing chamber increases. The raw material level can be optimized by changing the length of pipe projection in the small chamber. This feed level remains constant as the mill load changes.

Embodiments Embodiments will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view of a main part of a ball mill according to an embodiment of the present invention in a direction including an axial center line, and FIG. 2 is II-II of FIG.
FIG. 3 is a sectional view taken along the line, and FIG. 3 is an enlarged sectional view of an essential part of FIG.

Reference numeral 10 is a cylindrical mill casing, and a liner 12 is attached to the inner surface thereof. This mill casing 10
Although not shown, is rotatably supported by a bearing device about its axis, and is driven to rotate about its axis by a drive device.

The inside of the mill casing 10 is divided into a coarse crushing chamber 14 and a fine crushing chamber 16, and a reservoir chamber 18 is provided at the boundary between the crushing chambers 14 and 16. This reservoir chamber 18 is provided with a mesh plate 20 on the coarse crushing chamber 14 side, a blind plate 22 on the fine crushing chamber 16 side, and an enclosure plate provided so as to straddle the mesh plate 20 and the blind plate 22 (this embodiment). 24 in the example)
Is surrounded by. Reference numeral 26 is a frame having a U-shaped cross section, which is fixed to the mill casing 10, and the eye plate 20 and the blind plate 22 are disposed so as to be supported by the U-shaped parallel portion of the frame 26.

The eye plate 20 has a large number of slits or openings, and is arranged along the inner peripheral surface of the mill casing 10 so as to have an annular shape when viewed from the axial direction. A blind plate 22 is also provided along the inner peripheral surface of the mill casing 10, and a cylindrical opening 28 is formed by the surrounding plate 24 at the mill axial center portions of the eye plate 20 and the blind plate 22. There is.
An annular member 30 is fixed to the inner wall surface of the surrounding plate 24, and a wire mesh 32 is arranged in a direction to close the opening 28.

The inside of the reservoir chamber 18 is divided into a plurality of small chambers 36 by a raking plate 34 extending in the radial direction of the mill, the inside of each small chamber 36 is communicated with the fine crushing chamber 16, and the raw material powder is discharged from each small chamber 36. Fine grinding chamber
A pipe 38 is provided for feeding to 16. In this embodiment, the pipe 38 is provided with a straight pipe-shaped control pipe 40 that penetrates the surrounding plate 24, and a discharge hype 42 that is a curved pipe connected to the control pipe 40. As shown in an enlarged view in FIG. 3, an opening 44 is formed in the surrounding plate 24, and a short sleeve 46 is fixed to the mill center side of the opening 44, and the control pipe 40 is attached to the opening 44 and the sleeve 46. Has been inserted. Further, the sleeve 46, the control pipe 40 and the discharge pipe 42 are provided with flanges 46a, 40a, 42a, respectively, and these flanges are overlapped and connected to each other to connect the control pipe 40 and the discharge pipe 42 and Attachment support of the pipe 38 to the surrounding plate 24 is provided.

In the ball mill thus configured, the coarse crushing chamber 14
A large-diameter ball is accommodated therein, and a small-diameter ball is accommodated in the fine crushing chamber 16, where coarse crushing and fine crushing are performed. The raw material charged into the coarse crushing chamber 14 from the left side of FIG. 1 is crushed as the mill rotates, and then passes through the opening of the eye plate 20 into the reservoir chamber 18 (small chamber 36). Pour in. Each small room 36
The level of the granular material inside the control pipe is controlled when the small chamber 36 is located above the mill axis.
When it becomes higher than the tip of 40, the granular material flows through the tip opening edge of the control pipe 40 into the pipe 40, and then is fed into the crushing chamber 16 through the discharge pipe 42 to be finely crushed. It The raw material that has been finely pulverized thereafter is discharged to the outside of the mill through a discharge port (not shown) provided on the right side of FIG.

However, as described above, the discharge of the raw material from the small chamber 36 is mainly due to the flow of the granular material into the control pipe 40.
The raw material is retained in the small chamber 36 for the length of the protrusion. Therefore, due to this accumulated raw material, the coarse crushing chamber 14 to the reservoir chamber 18 (small chamber 3
The position where the material flows into 6) becomes high, the raw material level in the coarse crushing chamber 14 is maintained at a predetermined level, and energy loss due to ball striking, back plate, chipping and cracking of balls are prevented. Further, it is not necessary to lower the ball level, and the crushing ability is maintained.

Further, even if the load on the mill fluctuates, the raw material level in the coarse crushing chamber 14 is maintained substantially constant. That is, even if a large load is applied to the mill, the raw material granules flowing from the coarse crushing chamber 14 into the small chamber 36 quickly flow into the control pipe 40, and the raw material level in the small chamber 36 is the protruding length of the control pipe 40. It is almost commensurate with that.
Therefore, even in the heavy load state, the raw material level in the coarse crushing chamber 14 is the same as that in the steady load. On the contrary, even if the mill load becomes too small, the raw material level in the small chamber 36 is maintained, and the raw material level in the coarse crushing chamber 14 is maintained at the same level as in the steady state.

Therefore, it is possible to carry out a stable and efficient crushing operation without hitting the balls and the like regardless of the fluctuation of the load on the mill.

The control pipe 40 having different lengths is prepared in advance, and by changing the protruding length of the control pipe 40 into the small chamber 36, the raw material level in the small chamber 36 can be adjusted. Therefore, the raw material level in the coarse crushing chamber 14 can also be changed.

In the above-mentioned embodiment, the pipe 38 is provided with the discharge pipe 42 made of a curved pipe, and the raw material flowing into the pipe 38 from the small chamber 36 is promptly discharged toward the fine crushing chamber 16 to further improve the crushing efficiency. The effect is played.

In the above embodiment, the pipe 38 is provided in each of the small chambers 36 forming the reservoir chamber 18 provided in the axially middle portion of the mill casing 10.
However, in the present invention, the above structure can be applied to a portion for discharging the powder or granular material from the lowermost pulverization chamber 16 to the outside of the mill. In this case, the end plate of the mill casing is located at a position corresponding to the blind plate 22, and the opening 28
Is the outlet for the crushed material.

It is clear that the present invention is applicable to both dry and wet milling.

[Effect] As described above, in the mill of the present invention, the raw material level in the crushing chamber becomes a predetermined level, the crushing medium such as balls is not hit, energy loss is prevented, and
The back plate and balls are prevented from chipping or cracking, and the durability of the mill is improved. Further, the raw material level can be maintained at a predetermined level, the pulverization efficiency is improved, and the pulverization operation of the mill becomes extremely stable.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a ball mill according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 is an enlarged view of an essential part of FIG. 10 …… Mill casing, 14 …… Coarse grinding chamber, 16 …… Fine grinding chamber, 20 …… Eye plate, 22 …… Blind plate, 24 …… Surrounding plate, 38 …… Pipe.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yumitsu Emoto 2 1978, Ogushi, Ube, Yamaguchi Prefecture, Ube Cement Plant, Ube Industries, Ltd. (72) Shuji Asakami 2 1978, Ogushi, Ube, Yamaguchi Prefecture Ube Industries Ube Cement Factory Co., Ltd. (56) Bibliography Sho 59-74846 (JP, U) Sho 61-135548 (JP, U) Japanese Patent Sho 58-9702 (JP, B2)

Claims (2)

[Claims] 1. In a mill which contains a grinding medium inside and is rotated, an eye plate installed in an annular shape along an inner peripheral wall of the mill, and the eye plate is opposed to the eye plate at a predetermined interval in the axial direction of the mill. And a blind plate and a reservoir for the granular material, which is annularly defined by a surrounding plate on the axial side of the mill between the eye plate and the blind plate; in a direction including the radial direction of the mill. A scraping plate that is provided with a plurality of sheets and divides the accumulating chamber into a plurality of small chambers; for discharging powder particles from each small chamber, and is installed so as to penetrate the surrounding plate, and the tip is in the small chamber. A projecting pipe having an opening at the tip thereof; a projecting length of the pipe into the small chamber, when the small chamber occupies a position vertically above the mill axis,
The retention height of the powder or granules in the small chamber occupying the vertically upper position substantially matches, and the powder or granules in the small chamber can flow into the pipe only through the opening at the tip. Mill to do. 2. The storage chamber is provided midway in the axial direction of the mill to divide the inside of the mill into a coarse pulverizing chamber and a fine pulverizing chamber, and the pipe is directed to the fine pulverizing chamber on the axial side of the mill. A mill according to claim 1, characterized in that it is curved.