JPS6119307B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a conical ball mill for finely pulverizing cement raw materials, clinker, etc.

For conical ball mills, for example, West German patent no.
There is something like the one described in No. 1607562.
As shown in FIG. 1, it consists of a rotating container 1 having an approximately inverted truncated cone shape and a fixed cover 2 placed to cover the upper part of the rotating container 1. When the rotating container 1 receives a centrifugal force due to its rotation and rises above the side wall 1a of the rotating container 1 and reaches the fixed cover 2, the inertial force of the grinding medium 3 causes the guide vanes 4 on the inner surface of the fixed cover 2 to move upward.
This device moves inward along the rotary container 1 and falls down to crush the crushed material 6 in the rotary container 1, which is supplied from the crushed material input chute 5 provided at the top of the fixed cover 2.

This type of crusher carries the material to be crushed 6 in an air flow 7 and discharges it outside the machine through a duct 8 connected to the center of a fixed cover 2.In order to allow rotation of the rotating container 1, the fixed cover 2 While it is necessary to provide a gap 9 between the two, the gap must be made as small as possible to prevent the material to be crushed 6 from flying out of the machine through the gap 9.

However, at the rotational speed required for pulverization, the centrifugal force exerted on the material to be pulverized in the container is quite large.
When the above-mentioned seal gap is made small, a large centrifugal force is acting on the object 6 to be crushed near the gap 9 so that it tends to fly out of the machine, so the object 6 to be crushed does not stick to the gap 9. However, there is a drawback that stable continuous operation cannot be performed because fragments of the steel balls used as the grinding medium and other foreign objects get caught. On the other hand, if the gap is made large, particles cannot be prevented from flying out unless a large amount of air is sucked through the gap, resulting in a large pressure loss. In this way, the material to be crushed is discharged from the upper fixed cover together with the induced air, but the sealing portion of the gap 9 poses a problem.

Further, in order to carry the material 6 to be crushed in the air flow 7 and discharge it upward, a blower with a large air volume and high pressure is required, which is not preferable from the viewpoint of energy saving.

The present invention has been made in order to solve the above-mentioned problems, and the gap between the rotating container and the fixed cover is made larger than that of conventional devices, and the material to be crushed can be discharged to the outside of the machine with less power. The purpose of the present invention is to provide a conical ball mill that enables the rotation of the rotary container and the fixed cover to have a gap smaller than the diameter of the grinding medium and larger than the diameter of the object to be crushed. A slit for discharging the material to be crushed is bored in the side wall, and a casing is provided that completely surrounds the rotating container and the fixed cover, and a means for conveying the material to be crushed is interposed between the casing and the side wall of the rotating container. That's what happened.

The present invention will be described in detail below based on examples.

FIG. 2 is an overall sectional view of the crushing device 10 of the present invention, showing a container frame 11 and a liner 1 lined therewith.
The rotating container 1 having a substantially inverted truncated cone shape is composed of:
It has a built-in grinding medium 3 (steel balls, steel sill peb, etc.), and is rotatably driven by an electric motor 16 via a rotary shaft 13 fixed vertically to the lower surface of the bottom and supported by a bearing 14, and a speed reduction device 15.

Incidentally, the above-mentioned liner 12 is provided with a slit 17 as shown in FIG. The slope of the inclined wall 1a in which the slit 17 is formed may be linear or curved.

A fixed cover 2 is fixed to the machine frame 18 directly above the rotating container 1 with a gap 9 in between, and this gap 9 does not need to be made small in order to maintain airtightness inside the machine, so that the grinding media 3 will not fly out. The dimensions are determined as follows.

The above-mentioned fixed cover 2 is provided with guide vanes 4 as shown in FIG. 4, and the fixed cover 2 has a chute 5 in the center thereof into which the material to be crushed 6 is fed, and a chute 5 on the outer periphery of the chute 5 for air suction. A duct 8 is installed.

In addition, a casing 19 that completely surrounds the rotating container 1 and the fixed cover 2 described above is attached to the machine frame 18, and the conical mill is isolated from the outside air.
In the embodiment shown in FIG. 2, an air sliding conveyor 20 is interposed between the casing 19 and the rotating container 1 in an annular and inclined manner, and a chute 21 is installed at the lowest position passing through the casing 19. has been done.

Next, the operation of the crushing apparatus of the present invention will be described.

When the rotating container 1 in which the grinding medium 3 is charged in advance is driven by the electric motor 16, the grinding medium 3 is moved up the inclined side wall 1a of the rotating container 1 under the influence of centrifugal force. The grinding medium 3 that has reached the upper end of the inclined side wall 1a collides with the fixed cover 2 installed to cover the upper part of the rotating container 1 due to its inertia force, and a plurality of guide vanes 4 attached to the fixed cover 2 collide with the fixed cover 2 installed to cover the upper part of the rotating container 1. The guide blade 4 moves to the center, then falls away from the guide vane 4 and returns to the rotating container 1. The material to be crushed 6 is supplied into the rotary container 1 through a chute 5 provided in the center of the fixed cover 2, and due to the circulation behavior of the crushing medium 3 that leaves the above-mentioned guide vanes 4 and falls at the bottom of the rotary container 1. Shattered by impact. Furthermore, when moving along the inclined side wall 1a of the rotary container 1 together with the grinding medium 3, it is caught between the grinding medium 3 and the inclined side wall 1a or between the grinding media 3, and is mainly subjected to friction pulverization.

Incidentally, the object to be crushed 6 also moves up the inclined side wall 1a of the rotary container 1 together with the grinding medium 3, but since the slit 17 is bored in this inclined side wall 1a as described above, the object 6 moves up the inclined side wall 1a of the rotary container 1. Only the crushed material is discharged outside the rotating container 1 by centrifugal force. Further, objects to be crushed that have reached the upper end of the inclined side wall 1a and do not have enough inertia to rise to the fixed cover 2 are discharged to the outside of the rotary container 1 through the above-mentioned gap 9.

The material to be crushed 6 thus discharged falls onto an air sliding conveyor 20 arranged around the outer periphery of the rotary container 1, and the material to be crushed 6 is crushed by the air 23 that has been force-fed by a blower (not shown) and passed through the canvas 22. The fluidized material is sequentially conveyed to the lower end of the inclined annular air sliding conveyor 20 and discharged from the machine through the chute 21. Note that the conveying means between the rotating container 1 and the casing 19 is not limited to an air sliding conveyor, and may be a known scraper. When the above-mentioned air sliding conveyor 20 is adopted, when the air inside the machine is sucked through the duct 8 connected to a dust collector or induced blower (not shown), the inside of the crusher body surrounded by the rotating container 1 and the fixed cover 2, The space surrounded by the casing 19 and the air sliding conveyor 20 is maintained at a negative pressure to prevent dust from scattering outside the machine. At this time, duct 8
Some of the crushed materials that are discharged along with the airflow are collected by a dust collector. Note that it is sufficient that there is a gap between the rotating container 1 and the air sliding conveyor 20 that allows rotation of the rotating container 1.

The slit 17 formed in the inclined side wall 1a of the rotary container 1 described above may have any shape as long as it is suitable for discharging the material to be crushed 6, and FIG. 3 shows an arcuate slit. Note that this slit may be provided on the entire surface of the inclined side wall 1a, but as shown in FIG.
may be provided alternately. In this case, the surface of the liner 12a without slits allows the grinding media 3 to rise smoothly, which is convenient.

Next, FIGS. 5 and 6 show examples of crushing plant equipment to which the above-mentioned conical mill is applied. Fifth
In the figure, the material to be crushed that is supplied through a chute 31 is coarsely crushed in a single-chamber tube mill 32 and conveyed to a separator 34 by an elevator 33. The classified fine powder passes through the chute 35 to the next step, and the coarse powder passes through the chute 36 and is fed into the conical mill, which is the pulverizing device 10 for fine pulverization of the present invention, from the chute 5.

The powder from the crushing device 10 is fed into the elevator 33 again via the chute 37 and classified through the above-mentioned route. Note that the air sucked through the duct 8 is removed by a dust collector 38 and released into the atmosphere, and the dust obtained at that time is sent to the above-mentioned chute 35.
It may be sent to the next process together with the refined powder.

With this arrangement, the coarse pulverization process can be efficiently carried out using a tube mill in which impact force is dominant, and after removing fine powder therefrom, fine powder can be generated by the pulverizer of the present invention in which grinding force is dominant. This can improve the grinding efficiency of the entire system.

FIG. 6 shows an example of equipment different from that described above, which is combined with a two-chamber tube mill 39. The difference from the above example is that a part of the returned powder from the separator 34 is returned to the raw material input chute 31 via the chute 36a, and the powder from the conical mill, which is the pulverizing device 10 for fine pulverization, is classified. This is because one more separator 40 and another elevator 41 are provided to transport the separator 40 to the separator 40. With this arrangement, the amount of material to be crushed inside the two-chamber tube mill 39 can be maintained at the optimal level for fine powder production;
and existing tube mill 39, separator 34
It has the advantage that improvements can be made relatively easily when it is necessary to increase the crushing capacity of the machine.

As described in detail above, the present invention provides a gap between the rotating container and the fixed cover to an extent that is smaller than the diameter of the grinding medium and larger than the diameter of the object to be crushed, and a slit for discharging the object to be crushed is bored in the inclined side wall of the rotating container. In addition, a casing is provided that surrounds the rotating container and the fixed cover, and a means for conveying the material to be crushed is interposed between the casing and the side wall of the rotating container, so that the material cannot be crushed at the rotational speed necessary for pulverization. Although the centrifugal force applied to the pulverized material becomes considerably large, the gap between the seal parts can be reduced. On the other hand, since the pulverized material is discharged through the slit, there is no need for a large amount of exhaust air, which can prevent the pulverized material from adhering to the gap or biting of pieces of the steel balls used as the pulverizing medium or other foreign matter. is avoided. Further, there is no need to suck a large amount of air through the gap, and no large pressure loss is caused. In this way, the problems caused by the gap between the fixed cover and the conical mill are eliminated, dust is prevented from scattering outside the machine, and the power required to discharge the material to be crushed is significantly reduced. . In addition, the high mobility of the grinding media, which is a characteristic of conical mills, is maintained, and the drive power is small and the entire machine is compact, making it possible to perform complex grinding using impact force and frictional force, which are suitable for fine grinding. Become.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the main part of a conventional conical mill, Figure 2
The figure is an overall sectional view of the crushing device of the present invention, FIG. 3 is a view taken along the line shown in FIG. 2, and FIG. 4 is a view taken along the line shown in FIG.
5 and 6 are examples of plant equipment to which the crushing apparatus of the present invention is applied. DESCRIPTION OF SYMBOLS 1... Rotating container, 1a... Inclined side wall, 2... Fixed cover, 3... Grinding medium, 4... Guide vane, 8... Duct,
9... Gap, 13... Rotating shaft, 17... Slit, 19
...Casing, 20...Air sliding conveyor.

Claims (1)

[Scope of Claims] 1. A rotating container having a substantially inverted truncated conical shape that rotates around a vertical axis, and a fixed cover disposed to cover the upper part of the rotating container and having guide vanes attached therein, In a conical mill that performs pulverization by the circulation behavior of a pulverizing medium, the gap between the rotating container and the fixed cover is set to be smaller than the diameter of the pulverizing medium and larger than the diameter of the object to be crushed, and the object to be crushed is discharged onto the inclined side wall of the rotating container. The present invention is characterized in that it includes a casing which is provided with a slit and which surrounds the entire rotary container and the fixed cover, and a means for conveying the material to be crushed is interposed between the casing and the side wall of the rotary container. Grinding equipment. 2. The crushing apparatus according to claim 1, wherein the means for conveying the crushed material is an inclined annular air sliding conveyor. 3. Claims 1 or 2, characterized in that a duct for sucking air is provided at substantially the center of the casing to maintain the pressure inside the casing slightly lower than atmospheric pressure. Grinding equipment as described. 4. The crushing device according to any one of claims 1 to 3, wherein the slit is formed in a part of an inclined side wall of the rotating container.