WO2019170661A1

WO2019170661A1 - Stirrer mill with asynchronous pin arrangement

Info

Publication number: WO2019170661A1
Application number: PCT/EP2019/055426
Authority: WO
Inventors: Hans Kabbe; Eduard Nater; Achim Sturm
Original assignee: Bühler AG
Priority date: 2018-03-07
Filing date: 2019-03-05
Publication date: 2019-09-12
Also published as: EP3536405A1

Abstract

The invention provides a stirrer mill for treating flowable grinding stock. The stirrer mill has a mill container (2), a milling chamber (8), which is delimited by a container wall (9), and a stirring mechanism which can be rotated about a central longitudinal axis (19) and which comprises a cylindrical rotor (35). The milling chamber (8) can be filled at least partly with grinding bodies (43) with a diameter c. First tools (38) are attached to the rotor in the circumferential direction and in the direction of the central longitudinal axis, said first tools extending in the direction of the container wall, and second tools (74) are attached to the container wall in the circumferential direction and in the direction of the central longitudinal axis, said second tools extending in the direction of the rotor. The first tools are attached in the direction of the central longitudinal axis such that the first tools can pass between the rows of second tools during a rotational movement. According to the invention, if the number of second tools of a row arranged in the circumferential direction is less than or equal to the number of first tools of the corresponding row, all of the rows of second tools arranged in the direction of the central longitudinal axis and/or in the circumferential direction should not meet rows of first tools at the same time during a rotational movement. Accordingly, if the number of first tools of a row arranged in the circumferential direction is smaller than the number of second tools of the corresponding row, all of the rows of first tools arranged in the direction of the central longitudinal axis and/or in the circumferential direction should conversely not meet rows of second tools at the same time during a rotational movement.

Description

Agitator mill with asynchronous pin arrangement

The invention relates to a stirred mill according to the preamble of claim 1.

The invention makes reference to the European patent EP 1 992 412 A1. From this, such a stirred mill is known. Agitator mills are used to

Suspensions, ie solids in liquids to disperse. This is used, for example, in the production of adhesives, printing inks, cosmetics or pharmaceuticals. For this purpose, the millbase is fed into a grinding chamber of the stirred mill, which is between the

Outer wall of a rotor and a container wall is formed, and comminuted together with Mahlhilfskörpem, such as ceramic balls, which are also referred to as grinding media, and with the aid of tools. The stirring agglomerates are distributed and crushed crystal structures. The original particle size of 100-500 pm can be reduced to less than 3 pm.

Tools for shredding the product are on the one hand on the rotatably mounted rotor (also called rotor pins) and also fixed to the container wall (also called stator pins). They are usually arranged offset from one another in such a way that the rows of rotor pins can pass between the rows of stator pins during a rotational movement of the rotor. The suspension is passed through a Zuiuhrkanal in the grinding chamber of the agitator mill and the solids are there distributed or crushed using the grinding media and the tools. The finished product is then directed via a Mahlgut- discharge channel through a Mahlkörpertrenneinrichtung, in particular in the form of a protective sieve, to a drain line.

In operation, it happens that one filled with grinding media and product

Agitator mill can no longer be started. The reason for this is the compact grinding media product bed combined with the rotor and stator pins, which can lead to blocking. This requires a higher power to start up. Furthermore you can strong vibrations occur during operation and it comes to a faster wear of the tools. In the prior art, the rotor and stator pins are evenly distributed. The number of stator pins can be equal to the number of rotor pins or half in the circumferential direction. For example, mills are known which have 12 rows of 14 pins arranged in the direction of the rotor axis on the rotor and 12 rows of 13 pins on the stator.

It should also be noted that the pins are arranged so that they do not meet axially. For example, since when changing the grinding media, the rotor is moved out in the axial direction, the pins could otherwise be damaged in this process.

The invention is based, to block the agitator mill in the task

Start or stop to stop. As a result, the power required during startup is reduced and less vibration occurs during operation.

This object is achieved by the features in the characterizing part of claim 1. The essence of the invention is that, due to an irregular distribution of the tools or rotor and / or stator pins or a change in the number, all the tools or pins do not hit each other at the same time, and blocking can thus effectively be prevented.

In particular, the object is achieved by an agitator mill having the following features. The agitator mill has a grinding container and a grinding chamber which is delimited by a container wall and an agitator which can be rotated about the central longitudinal axis and has a rotationally symmetrical rotor. The grinding chamber is at least partially filled with Mahlhilfskörpem. On the rotor first tools are mounted in the circumferential direction and in the direction of the central longitudinal axis, which extend in the direction of the container wall and on the

Container wall are mounted in the circumferential direction and in the direction of the central longitudinal axis of second tools, which extend in the direction of the rotor. The first tools are mounted in the direction of the central longitudinal axis so that they can pass between the rows of second tools during a rotational movement of the rotor. By the invention is to be achieved that not all tools of that row in the circumferential direction, which has fewer tools, at the same time occur during rotation between adjacent tools of the corresponding opposite row.

In particular, should the number of second tools of a row arranged in the circumferential direction is less than or equal to the number of first tools of the corresponding row, according to the invention not simultaneously all the second tools arranged in the direction of the central longitudinal axis and / or in the circumferential direction of the container wall arranged rows meet in a rotational movement of the rotor on first tools of the corresponding arranged on the rotor rows. Correspondingly, conversely, when the number of first tools of a row arranged in the circumferential direction is smaller than the number of second tools of the corresponding row, not all first tools of the rows arranged in the direction of the central longitudinal axis and / or in the circumferential direction on the rotor are reversed simultaneously upon rotation of the rotor to meet second tools of the corresponding arranged on the container wall rows.

To accomplish this, the first tools mounted on the rotor and / or the second tools mounted on the container wall may be circumferentially offset at different angles to each other, the angles being measured in the plane perpendicular to the center-to-longitudinal axis. If the first tools are offset from one another at different angles, the second tools can be arranged uniformly in the circumferential direction, spaced at equal angles, and vice versa.

The attached to the container wall second tools can, for example, in

Circumferential direction in angles of 55 °, 70 °, 55 °, 55 °, 70 °, 55 ° to each other. In this case, the angles between the first tools in the circumferential direction may each be the same angle, in particular 30 ° or 60 °.

The number of the first tools mounted on the rotor and the number of the first

Container wall mounted second tools can in particular per row in

Circumferential direction should not be a multiple of each other.

Furthermore, the tools mounted on the rotor or on the container wall can form the shape of a J in a row in the direction of the central longitudinal axis. Thus occur in the Rotation of the rotor, the tools of this arranged in the direction of the central longitudinal axis series not simultaneously, but in succession between adjacent tools of the opposite row. Alternatively, to achieve this result, the tools mounted on the rotor or on the container wall in a row in the direction of the central longitudinal axis may form a C or an S shape.

The Mahlhilfskörper are preferably ceramic beads, which is typically a

Diameter smaller than 1.25 mm, preferably 0.02 mm to 0.8 mm. The

Mahlhilfskörper can also be designed as hard metal beads, steel beads or glass beads. Furthermore, stones or sand can be used as a grinding auxiliary body.

The invention further provides a rotor for a stirred mill, wherein the rotor can be offered as a spare part for an existing mill. The

Rotor according to the invention has asymmetrically arranged tools, wherein

For example, at least one row of the tools is not parallel to the direction of the central longitudinal axis, or in which tools in the form of a C, a J, or an S are arranged.

Further features, advantages and details emerge from the following

Description of the invention with reference to the drawing. It shows

1 shows a section of a stirred mill as a vertical longitudinal section of the

State of the art

2 shows a distribution of the tools according to a first embodiment

3 shows an alternative distribution of the tools after the first

embodiment

4 shows a distribution of the tools according to a second embodiment

Fig. 5: a distribution of the tools according to a third embodiment as

Row representation of the tools in the direction of the central longitudinal axis. Fig. 6: an alternative distribution of the tools after the third

Embodiment as a series representation of the tools in the direction of the central longitudinal axis

7 shows a section through the rotor and stator according to the third embodiment Fig. 1 shows a section of a stirred mill according to the prior art. The agitator mill shown in FIG. 1 has in the usual way a grinding container 2 with an internal grinding chamber 8. The grinding chamber 8 is at least partially filled with grinding bodies 43 with a diameter c. The diameter of the grinding media is usually less than 1.25 mm and is typically 0.02 mm <c <0.8 mm. The agitator mill also has an inner stator 22 and a rotor 35 rotatable about a central-longitudinal axis 19. On the rotor 35 first tools 38 are mounted in the grinding chamber. 8

protrude. On the container wall 9 or on the stator second tools 74 are mounted, which protrude into the grinding chamber 8. The first tools 38 and the second tools 74 are arranged on the one hand in the direction of the central longitudinal axis 19 in rows and on the other hand arranged in rows in the circumferential direction. The circumferential direction can also be considered as a plane perpendicular to the central longitudinal axis 19. Looking at one

Unwinding of the outer wall of the rotor 35 and the container wall 9 are in the prior art, the rows of first tools 38 and second tools 74 on perpendicular to each other arranged lines.

The first tools 38 and second tools 74 are offset relative to one another in the direction of the central longitudinal axis 19 in such a way that the first tools 38 rotate about the central longitudinal axis 19 between the rows of second tools 74 during a rotational movement of the rotor 35 can pass through. The first tools 38 and second

Tools 74 are preferably designed in the form of pins, in particular as round or cylindrical pins, which optionally identify nubs or profiled in any other way. However, the tools 38, 74 can also be made in any other form, such as, for example, as cams or diamonds. The processed millbase is passed through a gap between the rotor 35 and the inner stator 22 to a protective screen 30, the grinding media 43 stops, and flows through a drain line 31 from.

Fig. 2 shows an example of a first embodiment of the invention as a section through the rotor 35 and container wall 9 and the enclosed grinding chamber 8 in the plane perpendicular to the central longitudinal axis 19. The first tools 38 and rotor pins are circumferentially evenly in angles of Distributed 30 ° and protrude into the grinding chamber 8. The second tools 74 and stator pins are non-uniformly arranged at angles of 55 ° - 70 ° - 55 ° - 55 ° - 70 ° - 55 ° to each other and protrude into the grinding chamber 8. Thus, the container wall 9 has about half as many tools 74 as the rotor 35, due however, fewer tools 38, 74 collide simultaneously in the asymmetric distribution. In particular, not all second tools of a circumferentially arranged row pass simultaneously between adjacent first tools.

As a result, blocking the agitator mill can be effectively prevented. It will be understood by those skilled in the art that another distribution of tools 38, 74 may be made without departing from the scope of the invention.

Fig. 3 shows an alternative of the second embodiment of the invention as a section through the rotor 35 and container wall 9 and the grinding chamber enclosed therein 8 in the plane perpendicular to the central longitudinal axis 19. The second tools 74 and stator pins are non-uniform in the circumferential direction at angles from 65 ° - 50 ° - 65 ° - 65 ° - 50 ° - 65 ° to each other while the first tools 38 and rotor pins in

Circumferentially evenly offset in angles of 30 ° to each other.

Fig. 4 shows an example of a second embodiment of the invention as a section through rotor 35 and container wall 9 and the enclosed grinding chamber 8 in the plane perpendicular to the central longitudinal axis 19. The number of first tools 38 and second tools 74 is selected that they do not form a multiple of each other. In Fig. 4 ten first tools 38 are mounted on the rotor 35 each at an angle of 36 ° to each other, while the container wall 9 six second tools 74, each at an angle of 60 ° to each other. As in the previous embodiment, this means that fewer tools 38, 74 meet at the same time and thus blocking the

Rührwerksmühle be prevented due to the compact bed of Mahlkörpem and regrind. It will be understood by those skilled in the art that the embodiment just described is not limited to this distribution of tools, but other distributions may be convenient without departing from the spirit of the invention.

5 schematically shows sections of rotor 35 and container wall 9 along the central longitudinal axis 19, each having a row of first tools 38 and second tools 74.

In Fig. 5a, an arrangement according to the prior art is shown. In this case, the row of first tools 38 is arranged in the circumferential direction at the same distance from the row of second tools 74 and parallel to the central longitudinal axis 19. Fig. 5b shows one of the possible embodiments of the invention. In this case, the first tools 38 are offset in the circumferential direction so that they form the shape of a J in the direction of the central longitudinal axis 19. FIG. 5 c shows another possible embodiment in which the first tools 38 form the shape of a C in the direction of the central longitudinal axis 19.

FIG. 5 d shows a further possible embodiment, in which the first tools 38 form the shape of an S in the direction of the central longitudinal axis 19. For all three

Embodiments are achieved in that fewer tools 38, 74 meet at the same time and thus the risk of blocking when starting is reduced.

Figures 6a and 6b show further alternatives of the third embodiment, wherein at least one of the rows of first tools 38 or second tools 74 are not aligned parallel to the central longitudinal axis 19, wherein in the circumferential direction per row the distance between the tools is the same.

Figures 6c and 6d show further possible embodiments in which the second tools 74 are arranged in the axial direction on a bent line, wherein no part of the line is parallel to the central longitudinal axis 19.

Fig. 7 shows a section through the rotor 35 and container wall 9, wherein the first tools 38 and the second tools 74 according to the third embodiment, as shown in FIG. 6b, are arranged.

The embodiments just described solve the problem described above and the agitator mill is less prone to blocking. Since the tools 38, 74 are not arranged uniformly and thus fewer tools 38, 74 engage in one another at the same time, the risk of blocking due to the compact grinding media product bed can be reduced. As a result, the torque required for starting can be reduced,

Vibrations are reduced and the wear of the tools 38, 74 slows down, allowing the millbase to be processed more efficiently and faster. Furthermore, therefore, a smaller motor can be used, which can work space and energy efficient. Although the previously described embodiments and figures each show agitator mills with a vertical center-longitudinal axis 19, the described embodiments are also readily usable in a horizontal position or in an intermediate position.

Claims

claims

1. agitator mill for treating flowable millbase,

- With a grinding container (2) and a container wall (9), and

- With a about a central longitudinal axis (19) rotatable agitator (20) with a cylindrical rotor (35), and

a grinding chamber (8) delimited by the container wall (9) and the rotor (35),

- wherein the grinding chamber (8) is at least partially filled with Mahlhilfskörpem (43),

- Wherein on the rotor (35) in the circumferential direction and in the direction of the central longitudinal axis (19) rows of first tools (38) are mounted, which extend in the direction of the container wall (9) into the grinding chamber (8) in and

- Wherein on the container wall (9) in the circumferential direction and in the direction of the central longitudinal axis (19) rows of second tools (74) are mounted, which extend in the direction of the rotor (35) into the grinding chamber (8) in

- wherein the first tools (38) in the direction of the central longitudinal axis (19) are so angeodnet that they can pass between the rows of second tools (74) during a rotational movement of the rotor (35), characterized in that if the number of second tools (74) of a row arranged in the circumferential direction is less than or equal to the number of first tools (38) of the corresponding row, not all second tools (74) arranged in the direction of the central longitudinal axis and / or or in the circumferential direction on the container wall (9) arranged rows upon rotation of the rotor (35) on first tools (38) of the corresponding arranged on the rotor (35) rows, or if the number of first tools (38) one in the circumferential direction arranged row is smaller than the number of second tools (74) of the corresponding row, not at the same time all the first tools (38) in the direction of the central longitudinal axis and / or in Circumferential direction on the rotor (35) arranged rows in a rotational movement of the rotor (35) on second tools (74) of the corresponding arranged on the Behhälterwand (9) rows meet.

2. agitator mill according to claim 1, characterized

in that the first tools (38) attached to the rotor (35) and / or the second tools (74) attached to the container wall (9) are offset at different angles in the circumferential direction, and wherein the first and second tools (38, 74) in the direction of the central longitudinal axis (19) are arranged at equal intervals.

An agitator mill according to claim 2, wherein the angles between the second tools (74) in the circumferential direction are 55 °, 70 °, 55 °, 55 °, 70 ° and 55 ° and the angles between the first tools (38) in the circumferential direction, respectively the same angle, in particular 30 ° or 60 °.

4. agitator mill according to one of claims 1 to 3, characterized

the number of first tools (38) attached to the rotor (35) and the number of second tools (74) per row on the container wall (9) are not a multiple of each other in the circumferential direction.

5. Agitator mill according to one of claims 1 to 4, characterized

in that the first tools (38) or second tools (74) attached to the rotor (35) or to the container wall (9) form the shape of a J in the direction of the central longitudinal axis (19).

6. agitator mill according to one of claims 1 to 4, characterized

in that the first tools (38) or second tools (74) attached to the rotor (35) or to the container wall (9) form the shape of a C in the direction of the central longitudinal axis (19).

7. Agitator mill according to one of claims 1 to 4, characterized in that the first tools (38) or second tools (74) attached to the rotor (35) or to the container wall (9) form the shape of an S in the direction of the central longitudinal axis (19).

8. Agitator mill according to one of claims 1 to 4, characterized

in that at least one of the rows of first tools (38) or second tools (74) is not oriented parallel to the central longitudinal axis (19), wherein in the circumferential direction per row the distance between the tools (38, 74) is the same.

9. Agitator mill according to one of claims 1 to 4, characterized

in that the first tools (38) or the second tools (74) are arranged in the axial direction on a kinked line, wherein no part of the line is parallel to the central longitudinal axis 19.

10. Agitator mill according to one of claims 1 to 9, characterized

in that the auxiliary grinding bodies (43) have ceramic beads, hard metal beads, steel beads or glass beads, which typically have a diameter of less than 1.25 mm, preferably 0.02 mm to 0.8 mm.

A rotor (35) for an agitator mill, in particular an agitator mill according to one of the preceding claims, wherein the rotor (25) is cylindrical and has a central longitudinal axis (19), and wherein on the rotor (35) in the circumferential direction and in the direction of the central longitudinal axis (19) rows of first tools (38) are mounted, which extend radially outward from the rotor, wherein the first tools (38) in the circumferential direction and / or in the direction of the central longitudinal axis (19) are arranged unevenly.

The rotor (35) of claim 11, wherein the first tools (38) mounted on the rotor (35) in the direction of the central longitudinal axis (19) of each row form the shape of a J, C or S

The rotor (35) of claim 11, wherein at least one of the rows of first tools (38) is not aligned parallel to the central longitudinal axis (19), wherein in the circumferential direction per row the distance between the tools (38) is equal ,

14. A rotor (35) according to claim 11, wherein the first tools (38) are arranged in an axial direction on a kinked line, wherein no part of the line is parallel to the central longitudinal axis 19.

15. Rotor (35) according to one of claims 11 to 14, wherein the first tools (39) in

Circumferentially offset at different angles to each other.