EP3060345B1 - Apparatus and method for starting a stirring ball mill - Google Patents

Description

The present invention relates to an apparatus and a method for starting stirred ball mills. An apparatus for starting an agitator ball mill is described, wherein the agitator ball mill has a vertical grinding container. In the grinding container, a vertically extending stirring shaft is arranged, on which at least one refining element is arranged. The grinding container is largely filled with Mahlhilfskörpern.

In the published patent application DE 10 2011 010 527 A1 An agitating ball mill is described, which is connected to a grinding container and an axially extending in this agitator shaft, which is connected at least one end via a rotary feedthrough with the wall of the grinding container, characterized in that adjacent to the rotary feedthrough in the grinding container a rotary union covering protective disc is arranged ,

The in the DE 38 38 981 A1 described agitator mill has a grinding container with a limited by a Mahlraumwand cylindrical grinding space. In the latter, at least one agitator provided with protruding stirrers is arranged. The agitator and the grinding container are rotatably drivable about their respective mutually parallel axis. The grinding chamber is partially filled with auxiliary grinding bodies and has a Mahlgutzuführung and Mahlgutabführung with a Mahlgut-Mahlkörper-separation device. In order to enable both wet comminution and dry comminution, the stirrer axis has an eccentricity to the central longitudinal axis of the grinding chamber. Furthermore, in the region of the grinding chamber wall at least one of these directed into the grinding chamber, extending over a substantial part of the length of the grinding chamber, stationary deflector provided with an opening to the central longitudinal axis towards deflection.

The invention of DE 10 2006 012 489 A1 relates to an apparatus and a method for comminuting natural or artificial mineral products in one Size of 10 mm to 30 mm, which comminuted from the upstream process incurred, for example, in a good-bed roller mill, these solids in a work process continuously dry further shredded, then wetted with liquid and finely ground in this to a pumpable suspension, which subsequently is ground to the desired final fineness by means of stirred ball mills.

All of the abovementioned publications have in common that they describe vertical stirred ball mills in whose grinding container a large amount of auxiliary grinding bodies is arranged in the lower region. Since the Mahlhilfskörper generally have a very high density, the Mahlhilfskörperpackung is relatively heavy. Due to this relatively high weight, the tarnishing or starting up of the described stirred ball mills is made considerably more difficult. According to the prior art, this problem is usually solved by over-dimensioning the drive motor. As a result of this greatly enlarged drive, significantly increased costs are incurred for the production of the mill, and the energy requirement required in the production is also significantly higher than in the case of, for example, stirred ball mills. CH-380 455 discloses a lifting and lowering device of a stirrer, wherein the agitating unit can be raised together with the container lid.

DE-3022809 discloses a ball mill with a displacement body that can be lifted if the starting torque reaches a predetermined value. The shaft on which the displacement body moves is axially immovable. The invention has for its object to provide an apparatus for economical and reliable start a stationary agitator ball mill.

The above object is achieved by an agitator ball mill comprising the features of claim 1. Further advantageous features can be found in the dependent claims.

Another object of the present invention is to provide a method for economically and reliably starting a stationary stirred ball mill.

The above object is achieved by a method comprising the features of claim 7. Further advantageous features can be found in the dependent claims.

An apparatus for starting an agitator ball mill is described, wherein the agitator ball mill has a vertical grinding container. In the grinding container, a vertically extending stirring shaft is arranged, on which at least one refining element is arranged. The grinding container is mostly with Mahlhilfskörpern filled. The stirrer shaft can be raised by the device according to the invention for starting when the agitator ball mill is started. Here, it is of great advantage that only the stirring shaft is lifted with the grinding elements located thereon. The drive of the agitator ball mill remains in its position. The stirring shaft is mounted for this purpose in a socket and can be raised by the rotational movement of this socket. The bush is connected to the drive of the agitator ball mill and is moved by this corresponding rotational. Furthermore, the bush is provided with at least one recess in which at least one bolt, which is connected to the agitator shaft, is movably guided. The recess located in the socket has a slope. The larger the pitch of the recess, the greater is the axial distance that the bolt must travel during the rotary motion. However, as the pitch increases, the axial force to lift the agitator shaft decreases. With a flat slope, the situation is exactly the opposite. The distance by which the agitator shaft is raised is lower, and the axial force for lifting the agitator shaft at which the grinding elements are located increases accordingly.

In a further embodiment, it is possible that the recess has both a slope and a slope. In this embodiment, during the rotary movement of the bolt and with him the associated agitator shaft is briefly raised and shortly thereafter lowered in the region of the gradient again. In order to move the bolt back to its starting position, the agitator ball mill must be operated / moved backwards in this embodiment. In normal operation, the stirring shaft with the grinding elements is always in the lower position (starting position). The stirrer shaft is lifted during startup and then lowered again, which corresponds to the normal operating condition. On a subsequent start of the mill, it must be switched on in the opposite direction of rotation. The direction of rotation of the stirring shaft is thus dependent on the position of the bolt in the recess of the socket. The direction of rotation must be selected so that the bolt is guided into the other end position during the start.

In the first described embodiment, the stirrer shaft and the grinding elements can be stopped by stopping the agitating ball mill alone, by the weight force of the stirring shaft, the grinding elements lying on the grinding elements Mahlhilfskörpern turned back to a starting position and thus lowered to the starting position. In this embodiment, it is also conceivable that the mill is switched shortly after switching off in the opposite direction of rotation to actively support the lowering of the stirring shaft with the grinding elements.

In the socket, a retaining device may be present, which decelerates the stop of the bolt at an end position. The retaining device may be a spring, a damper or a similar component. Furthermore, it is also possible to support with the retaining device, the lowering of the stirring shaft and thus the return to the starting position. It will be apparent to those skilled in the art that there are a variety of ways and retainers to reduce the impact of the bolt. Therefore, the list made in advance does not limit the invention.

Furthermore, a method for starting a stirred ball mill is described in which the stirring shaft is lifted with the grinding elements by a rotary motion. The rotational movement is realized by a socket, wherein a bolt is raised by the rotational movement of the bush, which is arranged in a recess and fixedly connected to the agitator shaft. The bolt and with it the stirrer shaft is raised by the path corresponding to a pitch of the recess of the bushing.

• Figur 1 zeigt eine Rührwerkskugelmühle mit einer erfindungsgemäßen Vorrichtung.
• Figur 2 zeigt eine Rührwerkskugelmühle mit angehobener Rührwelle.
• Figur 3 bis Figur 7 zeigen erfindungsgemäße Vorrichtungen in verschiedenen Ausführungsformen.

In the following, embodiments of the invention and their advantages with reference to the accompanying figures will be explained in more detail. The proportions of the individual elements to one another in the figures do not always correspond to the actual size ratios, since some shapes are simplified and other shapes are shown enlarged in relation to other elements for better illustration.

• FIG. 1 shows an agitator ball mill with a device according to the invention.
• FIG. 2 shows a stirred ball mill with raised stirrer shaft.
• FIG. 3 to FIG. 7 show devices according to the invention in various embodiments.

The FIG. 1 shows an agitator ball mill 10, which is equipped with a device 30 according to the invention. The agitator ball mill 10 consists of a grinding container 12, in which a stirring shaft 14 with a plurality of grinding elements 16 is arranged. At the upper end of the agitator shaft 14 there is the drive 20 for the agitator shaft 14. In the lower region, the auxiliary grinding bodies 18 are arranged around the agitator shaft 14 and on the grinding elements 16. In the in the FIG. 1 illustrated starting position is the last grinding element 17 with a distance A from the grinding container bottom 13.

The FIG. 2 shows an agitating ball mill 10, in which the stirring shaft 14 and the grinding elements 16 were lifted by the device 30. The distance B between the grinding container bottom 13 and the last grinding element 17 is clear to the distance A, which in the FIG. 1 is shown enlarged. The position of the drive 20 has remained the same when lifting the agitator shaft 14 and the grinding elements 16.

The FIG. 3 shows a device 30 according to the invention, in which the stirring shaft 14 is introduced. The device 30 consists of a bushing 32, which is provided with a recess 34. In the recess 34 is a bolt 36 which is fixedly connected to the stirring shaft 14.

The FIG. 4 shows a device 30 according to the invention after the sleeve 32 has been rotated in the direction of rotation D. By moving the bushing 32 in the direction of rotation D, the agitator shaft 14 has been moved upwards in the lifting direction H. This lifting movement was caused by the fact that the bolt 36, which is firmly connected to the agitator shaft 14, has overcome the pitch of the recess 34. This happens because the bolt 36 is moved from the Ausgansposition 38 in the end position 40.

The FIG. 5 shows a device 30 according to the invention in a side view. In this view, the slope of the recess 34 in the socket 32 can be clearly seen. On the left side of the device 30, the bolt 36 is in the starting position 38. To reach the end position 40, the bolt 36 would have to overcome the pitch of the recess 34.

The FIG. 6 shows a plan view of the inventive device 30. In the middle of the device 30, the stirring shaft 14 with the bolt 36 can be seen. The bolt 36 is guided in the recess 34, which is located in the socket 32.

The FIG. 7 shows a further embodiment of the device 30. The device 30 consists of a bushing 32, in which the stirring shaft 14 is introduced. The stirring shaft 14 is provided with a bolt 36 which is guided in the recess 34 of the bushing 32. In the illustrated embodiment, the bolt 36 is located at the home position 38. For lifting and subsequently lowering the agitator shaft 14, the bolt 36 must be moved from the home position 38 to the end position 40. This is done as in the previously described embodiment by a rotational movement of the bush 32. In the in FIG. 7 1, it can be seen that the pitch of the recess along the slope line 44 increases from the starting point 38 towards the center line 42. From the center line 42 to the end point 40, the slope of the recess 34 decreases along the slope line 44.

The invention has been described with reference to a preferred embodiment. However, it will be apparent to those skilled in the art that modifications or changes may be made to the invention without departing from the scope of the following claims.

reference numeral

10

stirred ball mill

12

Cutting container

13

Mahlbehälterboden

14

agitator shaft

16

grinding element

17

last grinding element

18

auxiliary grinding

20

drive

30

contraption

32

Rifle

34

recess

36

bolt

38

starting position

40

end position

42

center line

44

slope line

A

distance

B

distance

D

direction of rotation

H

stroke direction

Claims (10)

1. An agitator ball mill (10) with a device (30) for starting the agitator ball mill (10), wherein the agitator ball mill (10) comprises a vertical grinding container (12), wherein a vertically running agitator shaft (14) is arranged in the grinding container (12), on which agitator shaft at least one grinding element (16) is arranged, and wherein the grinding container (12) is filled for the most part with auxiliary grinding bodies (18), wherein the agitator shaft (14), when the agitator ball mill (10) is started, can be raised by the device (30) for starting, characterised in that the agitator shaft (14) is mounted in a bushing (32) and can be raised by a rotational movement in the bushing (32), wherein the agitator shaft (14) with the grinding elements (16) located thereon is raised and the drive of the agitator ball mill remains in its position (10).
2. The device (30) according to claim 1, characterised in that the bushing (32) is provided with at least one recess (34), in which at least one bolt (36), which is connected to the agitator shaft (14), is guided in a moveable manner.
3. The device (30) according to claim 2, characterised in that the recess (34) has a rising gradient.
4. The device (30) according to claim 2, characterised in that the recess (34) has a rising gradient and a falling gradient.
5. The device (30) according to any one of claims 1 to 4, characterised in that the agitator shaft (14) and the grinding elements (16) can be lowered back into an initial position by stopping the agitator ball mill (10).
6. The device (30) according to any one of claims 1 to 5, characterised in that a restraining device is present in the bushing (32), said restraining device retarding the striking of the bolt (36) against an end position (40), wherein the restraining device is a spring, a damper or suchlike (30).
7. A method for starting an agitator ball mill (10), characterised in that the agitator shaft (14) with the grinding elements (16) is raised by a rotational movement.
8. The method according to claim 7, characterised in that the rotational movement is brought about by a bushing (32), wherein a bolt (36), which is arranged in a recess (34), is raised by the rotational movement of the bushing (32).
9. The method according to any one of claims 7 or 8, characterised in that the bolt (36) is raised over a path which corresponds to a rising gradient of the recess (34) of the bushing (32).
10. The method according to any one of claims 7 to 9, characterised in that the striking of the bolt (36) against an end position (40) is prevented by a restraining device in the bushing (32) and/or that the device (30) for starting an agitator ball mill (10) is moved back into a starting position (38) by the restraining device.

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