Agitator mill with special drive

Abstract

The present invention relates to an agitator mill (1), in particular in the form of a full-volume disc mill, comprising a grinding vessel (2) and an agitator shaft (3) circulating in the grinding vessel (2) about a horizontal axis (6), the agitator shaft (3) being non-rotatably connected to the agitator shaft (3) and supporting a plurality of grinding discs (4) spaced apart along the horizontal axis (6), each of the grinding discs (4) having a slot or opening. The agitator mill (1) is characterized in that it comprises drivers in the region between two of the grinding discs (4), which circulate synchronously with the grinding discs (4) during grinding and which directly move the grinding bodies, preferably radially, in response to the circulation of the grinding bodies, thereby imparting a radially outward component of motion to at least some of the grinding bodies in contact with the grinding discs.

Description

[Technical Field]

[0001] The present invention relates to a stirring mill equipped with a driver according to the preamble of claim 1. [Background technology]

[0002] First, the basic principle of the agitation mill will be explained based on FIG.

[0003] 1 shows diagrammatically an agitator mill 1 with a horizontal agitator shaft 3. The grinding bodies arranged in the grinding vessel 2 and generally configured as steel or ceramic balls have been omitted.

[0004] During operation of the agitator mill 1, the material to be ground is pumped through the inlet 101 of the agitator mill 1 into or through the grinding space 14 enclosed in the grinding vessel 2. In the case of wet grinding, the material to be ground is a suspension or dispersion consisting of a liquid, usually in the form of water, and solids. Alternatively, such agitator mill 1 can also be used for dry grinding. In this case, the agitator mill 1 can be designed, for example, as an agitator mill with a vertical shaft, through which the material to be ground is conveyed, usually in a downward flow, by a gaseous fluid.

[0005] According to its broadest aspects, the present invention relates to both types of agitator mills. The present invention is particularly suitable for agitator mills with a horizontal agitator shaft 3.

[0006] Rotation of the agitator shaft 3 about the agitator shaft axis 6 causes rotation of a grinding element, which is non-rotatably connected to the agitator shaft 3 and is configured as a grinding disk 4 and is often referred to as such. In the context of the present invention, it is equally possible for the grinding element to be formed in the form of individual pins, as will be explained below. However, since the use of grinding disks is preferred in the context of the present invention, only reference will be made below to "grinding disks" and only such grinding disks will be shown as grinding elements. To generate the rotational movement, the agitator shaft 3 can be driven by an electric motor, for example via a belt drive. In this case, the drive of the agitator mill 1 is usually arranged in a housing adjacent to the grinding vessel 2. For clarity, the drive and housing are not shown in FIG. 1.

[0007] As the grinding discs 4 rotate, the grinding bodies located in the grinding space 14 and in the vicinity of the grinding discs 4 are entrained (entangled) in the circumferential direction of the grinding vessel 2. In the central region between the two grinding discs 4, the moved grinding bodies flow back again in the direction of the agitator shaft 3 when they reach the apex region. In this way, a circulating movement of the grinding bodies occurs between the two grinding elements or grinding discs 4. This circulating movement is schematically shown in Figure 1 by two dashed arrows (two-dot chain arrows) in the free space between the first and second grinding discs 4 (only the upper region of the cross-section of the agitator mill 1, as seen from the inlet 101).

[0008] The movement of the grinding bodies causes collisions and over-rolling between the solids in the grinding material suspension pumped through the grinding vessel 2 and the grinding bodies. These collisions and over-rolling result in chipping of fine particles from the solids in the grinding material suspension, so that the solids arriving at the outlet 102 of the agitator mill 1 are ultimately significantly smaller than the solids fed at the inlet 101.

[0009] To prevent the grinding bodies from being released from the grinding space 14, a screen 103 is usually mounted in front of and / or supported by the outlet 102. A basket 104 is mounted around the periphery of the screen 103 and surrounds it. The basket serves to prevent the grinding bodies, which would tend to be pushed towards the screen by the pressure of the feed pump, from exerting a grinding body pressure that would be harmful to the screen.

[0010] Such agitator mills, in particular the full volume disc mill shown in Figure 1, are characterized by the formation of large spaces between directly adjacent grinding discs 4, which, as mentioned above, are substantially filled with grinding bodies. This type of full volume disc mill is particularly characterized by the use of grinding discs 4 as grinding elements and the grinding vessel 2 having an inner diameter D B is the diameter D of the stirring shaft 3 W In this case, the outer diameter of the agitator shaft 3 in the area between two adjacent grinding discs 4 is 2.5 times or more than the diameter D W It is understood as.

[0011] Even if gaps or openings are provided that allow the grinding bodies to move from the area between two grinding discs 4 to the area between two adjacent grinding discs 4, due to the appropriate packing density, the grinding bodies will substantially remain in the areas between the two grinding discs 4, respectively.

[0012] In the agitator mill 1, a fluid is pumped from the inlet 101 through the hollow spaces between the grinding bodies to the outlet 102. In this case, a feed pump is used. This feed pump flow of fluid carries the material to be ground through the agitator mill 1.

[0013] Due to the rotation of the agitator shaft 3 and the grinding discs 4 connected to it, the grinding bodies are eventually also entrained by friction on the grinding discs 4. As mentioned above, this causes the grinding bodies to rotate in the circumferential direction. In this case, the grinding bodies roll against each other on the grinding vessel 2 and on the grinding discs 4 in a grinding effect. The material to be ground is in particular ground by the pulse effect of the grinding bodies moving towards each other and then colliding with each other and the grinding effect mentioned above.

[0014] In this case, the problem repeatedly arises that the grinding bodies do not have sufficient dynamic movement in the free space between two adjacent grinding discs 4, or do not have a sufficiently strong movement in the radial vicinity of the agitator shaft 3 where the feed pump tries to create a transverse flow, and / or the circulating movement of the grinding bodies does not come close enough to the radial vicinity of the agitator shaft 3.

[0015] As a result, the fluid supplied by the feed pump and carrying the grinding material, instead of first circulating for a short time in each free space between two grinding discs 4, passes successively through the free spaces between two adjacent grinding discs 4 in the shortest possible way, which leads to the so-called leading.

[0016] When leading occurs, the grinding material does not come into sufficient and intensive contact with the grinding bodies, and therefore does not grind sufficiently. The general movement of the grinding material in response to such "leading" is also exemplarily shown in Figure 1 by the curved arrows as a movement from the inlet 101 through the free space between the first and second grinding discs 4 (only the upper region of the cross-section of the agitator mill 1 as seen from the inlet 101).

[0017] The leading problem is particularly undesirable in the case of full volume disc mills, because in such agitator mills the free space between two adjacent grinding discs 4 tends to protrude, which tends to prevent sufficient movement of the grinding bodies. Summary of the Invention [Problem to be solved by the invention]

[0018] In view of the above background art, an object of the present invention is to provide an agitation mill with improved grinding effect. [Means for solving the problem]

[0019] According to the invention, this problem is solved by the features of the first independent claim.

[0020] For this purpose, an agitator mill, in particular in the form of a full-volume disc mill, is proposed, which comprises a grinding vessel and an agitator shaft circulating about a horizontal axis in the grinding vessel, the agitator shaft being connected so as not to rotate relative to one another and supporting a plurality of grinding discs spaced apart in the direction of the horizontal axis, each grinding disc having a slot or opening. As mentioned above, a full-volume disc mill of this type uses grinding discs as grinding elements and has an inner diameter D of the grinding vessel at least. B is the diameter of the stirring shaft D W In this case, the outer diameter of the agitator shaft in the area between two adjacent grinding discs is 2.5 times or more than the diameter D W It is understood as.

[0021] The agitator mill according to the present invention is characterized in that it comprises driver bodies in the region between two immediately adjacent grinding discs, which circulate synchronously with the grinding discs during grinding. These driver bodies then directly displace the grinding bodies in response to the circulation of the grinding bodies, preferably primarily or substantially radially, thereby imparting a primarily or substantially radially outward motion component to at least some of the grinding bodies that contact the driver body. Thus, after collision with the driver body, the motion vector locally generated in each grinding body has a radially outward motion component, which accounts for at least 60%, preferably at least 75%, of the total motion vector. It is important to note, however, that this does not apply to each grinding body after collision with the driver body, but in fact applies only to at least some of them. The number of grinding bodies that actually collide with the driver body depends on many factors, including the design of the driver body, the conveying speed, the dimensions of the grinding bodies, and the grinding material.

[0022] In this way, preferably, each grinding body is supplied with a pulse, so that each grinding body transmits a pulse to at least one grinding body that is in contact with it, which in turn transmits a pulse to the grinding body that it hits, i.e. this results in a pulse sequence whose origin is the transmission of pulses from the driver to the grinding body that is in contact with it.

[0023] This results in an improved circulation of the grinding bodies, with the grinding bodies being provided with a component of movement, particularly in the radially outward direction, for at least some of the grinding bodies, in particular in that the grinding bodies in the vicinity of the agitator shaft are additionally activated, so that the aforementioned circulation movement of the grinding bodies is closer to the circulation surface of the agitator shaft.

[0024] In this way, the effectively used grinding space in terms of the grinding effect is generally increased and / or the grinding effect on the material to be ground is enhanced. Furthermore, the leading number is also increased, since an increased movement of the grinding bodies in the entire grinding space radially outward of the stirring shaft is ensured, thereby improving the entrainment of the material to be ground.

[0025] There are various options available in the design of the present invention to further enhance its effectiveness or usefulness.

[0026] In a particularly preferred embodiment, the driver has at least one portion having a non-circular surface shape relative to the horizontal axis of the agitator shaft, which at least one portion forms a pulse-generating portion that displaces the grinding bodies in response to rotation of the driver. This "non-circular surface shape" is preferably achieved by providing several flat portions on the driver. These flat portions are preferably formed in a circumferential region so as to at least partially flatten an otherwise circular cross-section. It is important to note that the driver can also be designed so that multiple flat portions are provided at least partially around the circumference of the driver, so that each cross-section no longer has any circular region at all. These flat portions are preferably formed as flat surfaces and can additionally be formed to extend parallel to the longitudinal axis of the driver, and thus the axis of the agitator shaft, or can be formed to have a predetermined angle of attack relative to the longitudinal axis of the driver. In this way, the flattened surface of the bushing effectively functions as a pulse-generating portion, in this case only being subject to reduced self-wear. Furthermore, it is generally important to note that each portion having a "non-circular surface shape" does not necessarily have to simultaneously function as a pulse-generating portion.

[0027] Furthermore, the driver is particularly preferably a bushing that engages on the agitator shaft in the free area between the grinding discs, or is integrally formed by the agitator shaft in this area, or is an integral part that protrudes from the front side of at least one grinding disc, with one of the above-mentioned options, a single bushing, being preferably located between two directly adjacent grinding discs. This ensures that the driver can be easily mounted in place between the grinding discs (easy assembly and no significant manufacturing effort). In this case, a preferred embodiment of the driver is an external bushing that surrounds the agitator shaft in the area between at least two adjacent grinding discs. Since this embodiment is clearly preferred, only a driver in the form of a bushing will be mentioned below, and therefore only the term "bushing" will be used. However, it is important to emphasize that other driver embodiments can also have design features of this type, as explained below. However, since the bushing shape is clearly a preferred embodiment, the term "bushing" will be used below to simplify the term "driver preferably in the form of a bushing."

[0028] In a further preferred embodiment, the bushing comprises an initial shape of a body having a polygonal cross-section, preferably a square cross-section, the body having at least a partially tapered portion between its front sides, the cross-section of the tapered portion having a smaller circumference than the polygonal cross-section of the initial shape.

[0029] On the other hand, this has manufacturing advantages, since the bushing is preferably a partially twisted polygon. Furthermore, the aforementioned "non-circular surface shape" or flat portion can be easily provided on the bushing. This allows, for example, the bushing to be maintained from each front side to the circumferential narrowing portion without machining, and this area already integrally forms various pulse-generating portions due to its "angular" polygonal basic shape. Furthermore, the aforementioned tapered portion on the bushing allows the grinding bodies to reach closer to the original agitator shaft. This further expands the grinding space, and as described above, the desired circulatory movement of the grinding bodies can be achieved over a wide area, even near the agitator shaft surface.

[0030] This tapered section also has various advantages, especially in combination with the flat section mentioned above, since the flat surface extending into the edge region with a larger diameter adjacent to the tapered section has a special blade effect.

[0031] In addition, it is particularly preferred that the cross section of the tapered section is largely circular, preferably with a constant diameter over the entire length of the tapered section. On the one hand, this is easier to achieve from a manufacturing standpoint, and on the other hand, the fact that the agitator shaft preferably also has a circular cross section ensures that the grinding bodies are guided to approach the agitator shaft surface uniformly over the entire circumference of the bushing. The design of the tapered section has a significant influence on the flow behavior of the grinding bodies. For example, in the case of a circular embodiment, the tapered section does not substantially produce a radially outward pulse effect. Therefore, there is no significant countermovement to the desired grinding body movement in the shaft axial direction, and the swirling movement of the grinding bodies toward the bushing in the center between the two grinding discs is not slowed down. This allows the grinding bodies to flow unimpeded into the area near the shaft, and no grinding body-free spaces are left near the shaft. This generally reduces the occurrence of leading.

[0032] Furthermore, it is particularly preferred that the transition between each front and / or front portion and the tapered portion is inclined, preferably conically or spherically inclined, so that the grinding bodies circulating in the area between the grinding discs are urged to flow towards the shaft axis, i.e., as part of their downward movement, for example, and are again urged to move more strongly into the central area between the two grinding discs, thereby intensifying the swirling of the grinding bodies in the free area between the two grinding discs.

[0033] The "front portion" exists when the initial front cross section is still maintained up to a predetermined circumferential reduction towards the center of the bushing, as described above.

[0034] In a further preferred embodiment, the tapered portion of the bushing is edged against the pulsing portion by a curved surface so as not to form a pulsing portion in response to rotation of the bushing. Thus, the "blade effect" of the bushing can be set by the ratio of the surface area of ​​the tapered portion to the surface area of ​​the pulsing portion, i.e., the strength of the pulsing portion formed by the bushing, or how strongly the pulsing portion displaces the comminuting bodies.

[0035] Furthermore, particularly preferably, the bushing has an inclined surface in its tapered section region, preferably in the transition region between the tapered section and the front side and / or between the tapered section and the front side, which is designed so that the primarily or essentially circumferential movement of the agitator shaft is forced onto the grinding bodies by the rotation of the inclined surface, in particular the bushing. As a result, the grinding bodies coming from the center between the two grinding discs are deflected toward the grinding discs near the shaft and moved radially outward from the inclined surface toward the grinding discs in order to support the "friction promotion" of the grinding disc walls and accelerate the grinding bodies there. In this case, the grinding bodies are more likely to swirl and / or rotate about their own axis in the free space region between two directly adjacent grinding discs, which in both cases increases the grinding effect.

[0036] Furthermore, it is particularly preferred if the tapered portions of the bushing are free of pulse-generating portions, i.e., completely free or substantially free of them. This allows for a controlled influence on the "blade effect" in the bushing. Even if each tapered portion is cut (invaded) by a flat portion, the pulse-generating effect in the tapered portion area is negligibly small compared to the pulse-generating portion.

[0037] In a further preferred embodiment, the pulse-generating parts are mostly or entirely, i.e. absolutely entirely or substantially entirely, arranged in a region adjacent to the front of the grinding discs, which preferably occupies less than ¼ of the distance between two directly adjacent grinding discs, measured in the direction of the horizontal axis of the stirring shaft, so that a suitable circular movement of the grinding bodies is achieved.

[0038] Furthermore, it is particularly preferred if the grinding discs have at least one, preferably several, openings through which the grinding bodies can reach from the intermediate space between two grinding discs into the adjacent intermediate space between two grinding discs. The "openings" can be windows bordered on all sides or slots projecting inward from the maximum outer diameter. These openings allow the material to be ground to pass from the inlet to the outlet of the agitator mill.

[0039] In a further preferred embodiment, flow breakers are arranged between the grinding discs, protruding from the inner surface of the grinding vessel into the free area between the two grinding discs, preferably directly above the tapered portion of the bushing, ideally in its central area. These flow breakers are usually pins, ideally aligned with each other in the circumferential direction, so that they do not slow down or do not significantly slow down the circumferential circulation of the grinding bodies.

[0040] Furthermore, the flow breaker can be preferably arranged asymmetrically in the circumferential direction, i.e., in the intermediate space between two directly adjacent grinding discs, closer to one grinding disc than to the other. The above applies otherwise. Depending on the shape of the bushing, the flow breaker and its arrangement can provide a favorable flow of grinding bodies in the area between two adjacent grinding discs. The flow breaker thus "loosens" the ball packet formed by the grinding bodies. Due to the centrifugal force of the rotating agitator shaft, this "ball packet" tends to densify on the container wall. Ball packets with such a density move slowly and therefore provide little impact energy for grinding purposes. The flow breaker adequately loosens the ball packet, which further accelerates the gyration of the grinding bodies. [Brief explanation of the drawings]

[0041] [Figure 1] 1 is a cross-sectional side view of a prior art agitator mill, with a schematic depiction of the flow of grinding bodies (dotted arrows) and the flow of grinding material (solid curved arrows). FIG. [Figure 2] 2 is a cross-sectional side view of an agitator mill according to the present invention, similar to FIG. 1, illustrating a first exemplary embodiment of a bushing and the resulting flow of grinding bodies (dash-dotted arrows). [Figure 3] 3 is a cross-sectional side view of an agitator mill according to the present invention, similar to FIG. 2, illustrating a second exemplary embodiment of a bushing and the resulting flow of grinding bodies (dash-dotted arrows). [Figure 4] 4 is a three-dimensional view of the second exemplary embodiment of the bushing according to the present invention in FIG. 3. FIG. [Figure 5] FIG. 5a is a side view of a third exemplary embodiment of a bushing according to the present invention, and FIG. 5b is a three-dimensional view of the exemplary embodiment. [Figure 6] FIG. 6a is a three-dimensional view of a fourth exemplary embodiment of a bushing according to the present invention, FIG. 6b is a front view of the exemplary embodiment, and FIG. 6c is a side view of the exemplary embodiment. [Figure 7] FIG. 7a is a three-dimensional view of a fifth exemplary embodiment of a bushing according to the present invention, FIG. 7b is a front view of the exemplary embodiment, and FIG. 7c is a side view of the exemplary embodiment. [Figure 8] FIG. 8a is a three-dimensional view of a sixth exemplary embodiment of a bushing according to the present invention, FIG. 8b is a front view of the exemplary embodiment, and FIG. 8c is a side view of the exemplary embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0042] FIG. 1 illustrates a prior art technology, which has already been described in detail in the "Background Art" section. Therefore, FIG. 1 will not be described in further detail here. However, it is important to point out that in an agitator mill 1 configured in this manner, the desired mixing of the grinding bodies does not occur in the area between two adjacent grinding discs 4. Although the grinding bodies undergo the desired circulating motion (see the dashed-dotted arrows), this circulating motion is not dynamic enough and does not reach the vicinity of the agitator shaft 3. Therefore, "leading" occurs particularly in this area. This means that the grinding bodies do not remain in the area between two adjacent grinding discs 4 for a sufficient time before passing through the openings of the grinding discs 4 and "leading" directly into the adjacent area between the two grinding discs 4, resulting in no or only partial circulating motion and therefore in the failure to achieve the desired grinding effect. For ease of explanation, each space between two adjacent grinding discs 4 will be referred to below simply as a "grinding chamber," and these grinding chambers are part of the overall grinding space 14.

[0043] 2 shows an agitator mill 1 according to the invention with a drive body designed according to the invention, in the same way as in Fig. 1. Again, for the sake of clarity, the grinding bodies, the grinding material and the drive body of the agitator mill 1 have been omitted.

[0044] In the embodiment shown and in the further figures, the driver is configured as a bushing 8, which surrounds the agitator shaft 3 between at least two adjacent grinding discs 4 and is preferably pressed onto the projections of the agitator shaft. The agitator shaft 3 is therefore preferably completely surrounded in these areas by the bushing 8. In Figure 1 and all other further figures, the driver is shown in the form of a bushing 8, which will hereinafter be referred to simply as a "bushing" for the sake of simplicity. The exact design of these bushings 8 will be explained in more detail below.

[0045] 2, the mounting of the bushing 8 between the grinding discs 4 can be seen, as well as the formation of grinding chambers radially outward from the bushing. The circulating movement of the grinding bodies (dash-dotted arrows) is shown exemplarily and diagrammatically in relation to the grinding chambers. However, this circulating movement is much more dynamic (not shown) than the circulating movement shown in FIG. 1, and in particular occurs closer to the surface of the bushing 8 than to the equivalent agitator shaft surface shown in FIG. 1.

[0046] In this way, the desired dynamic circulation movement of the grinding bodies is achieved in particular with flow breakers 12, which are designed as protrusions projecting radially inwards and are preferably formed in the shape of pins. The flow breakers 12 are mounted periodically in the circumferential direction on the inner wall of the grinding vessel 2.

[0047] Leading is reduced as the ground material remains in each grinding chamber for a longer period of time and is entrained by the circulating motion, which provides an additional grinding effect to the ground material, as shown diagrammatically by the flow of ground material (three solid curved arrows leading from the inlet 101 into each grinding chamber).

[0048] This desired circulating motion occurs in particular because the pulse-generating portion 7 of the bushing 8 directly displaces the comminuting bodies, preferably radially, in response to the circulation of the comminuting bodies, thereby imparting a radially outward component of motion to the comminuting bodies impinging on the pulse-generating portion 7 of the bushing 8. The pulse-generating portion 7 and the individual sections of the bushing 8 are described in more detail below.

[0049] Like FIG. 2, FIG. 3 shows the same view of the agitator mill 1, but with a second embodiment of the bushing 8. FIG. 3 is completely similar to the agitator mill 1 in FIG. 2. In FIG. 3, the circular movement of the grinding bodies is indicated by the dashed-dotted arrows. As can be further seen from FIG. 3, the grinding bodies are pushed toward the pulse-generating section 7 over the tapered section 9 or the transition section 13 adjacent to the tapered section 9. FIG. 3 also shows the flow arrows of the grinding material, which tends to "lead" near the shaft, i.e., skip the grinding space unground or not ground to the desired intensity. In this case, some of the grinding material is mixed in with the circulating movement of the grinding bodies, but it is clear that various leading movements also occur, which should be prevented.

[0050] This embodiment of the bushing 8 from FIG. 3 is shown again three-dimensionally in FIG. 4, where the configuration of such a bushing can be seen. The initial body or base of the bushing 8 preferably initially has a polygonal cross-section. In the example of FIG. 4, this can be considered an octagon, or rather a chamfered square. Such a bushing 8 further comprises a central through-hole for attaching the bushing 8 to the stirring shaft 3. The bushing 8 comprises two front sides 10. From these front sides 10 towards the center of the bushing 8, the initial basic shape is maintained for several millimeters, thereby forming front portions 11. From these front portions 11 towards the center, a transition region 13 is formed, which in the illustrated embodiment is spherically designed. This transition region 13 transitions in the central region of the bushing 8 into a tapered portion 9 with an at least partially circular cross-section.

[0051] In this case, the circumference of each cross section decreases continuously from the front portion 11 to the tapered portion 9 .

[0052] This second embodiment of the bushing 8 in FIG. 4 further comprises, on each of the four sides, a connecting web 16 which connects the front sides 10 to one another and bridges the tapered portions 9 .

[0053] In Figure 4, the pulse-generating sections 7 formed in this way are shown with hatching. As mentioned above, these pulse-generating sections 7 have the function, inter alia, of generating pulses that act radially outward on the grinding bodies, which are preferably guided from the tapered section 9 via a transition region 13 to these pulse-generating sections 7 and / or to the grinding discs 4.

[0054] In general, preferably, the motion vector locally produced in each grinding body after collision with the pulse-generating portion 7 has a radially outward motion component, which motion component accounts for at least 60%, preferably at least 75%, of the total motion vector.

[0055] Furthermore, after collision with the tapered portion 9, the motion vector locally produced in each grinding body has an axial motion component, which motion component accounts for at least 60%, preferably at least 75%, of the total motion vector.

[0056] A further embodiment of the bushing 8, shown in Figures 5a and 5b, shows that the tapered portion 9 does not need to be bridged by a connecting web 16 at all. The bushing 8 again has a polygonal base, which in the illustrated embodiment has a hexagonal shape. This basic shape is again maintained for several millimeters from each front side 10 until it transitions via a transition region 13 into the tapered portion 9. In this case, the tapered portion 9 has a circular cross section. The pulse-generating portion 7 of the bushing 8 is again shown hatched. Figure 5a also shows the bushing axis 15, which, in a given manufacturing and assembly scenario, preferably substantially coincides with the rotation axis of the stirring shaft 3.

[0057] In order to facilitate assembly of the bushing 8 onto the agitator shaft 3 and to prevent rotation relative to the agitator shaft, the bushing 8 preferably further comprises a plurality of grooves 17 at the bottom of the central through-hole, over the entire length of the bushing 8. Of course, for this purpose the agitator shaft 3 must have thickened portions that are complementary in shape and can engage with these grooves 17.

[0058] Figures 6a to 6c show an embodiment of a bushing 8 which is formed almost identically, except that, in comparison with the previous embodiments, this embodiment has an initial body with a purely square initial shape.

[0059] The fact that the pulse-generating portion 7 cannot be formed by merely extending an initial shape becomes clear on the basis of a further embodiment of a bushing 8 shown in Figures 7a to 7c. In this case, the pulse-generating portion 7 (also hatched) has a planar flat portion parallel to the bushing axis 15. The original initial shape of the bushing 8 is a square bushing, which is twisted by a curved tapered portion 9.

[0060] The tapered section 9 itself may be only a few millimeters wide, or may have only the connection between the transition areas 13 meeting each other in the middle of the bushing 8. Figures 8a-8c show an embodiment designed in this way. [Explanation of symbols]

[0061] 1. Agitator mill 2. Grinding container 3 stirring shaft 4 Grinding discs 6 Horizontal axis or stirring shaft axis 7 Pulse generation section 8 Bushings 9 Tapered section 10 Front of bushing 11 Front part of bushing 12 Flow Breaker 13 Transition or transition area 14 Crushing chamber 15 Bushing axis 16 Connected Web 17 Groove 101 Entrance 102 Exit 103 screens 104 Basket D B Inner diameter of grinding container D w Stirring shaft diameter

Claims

1. 1. An agitator mill (1), in particular in the form of a full-volume disc mill, comprising a grinding vessel (2) and an agitator shaft (3) circulating in the grinding vessel (2) about a horizontal axis (6), the agitator shaft (3) being connected to the agitator shaft (3) in a non-rotatable manner relative to the agitator shaft (3) and supporting a plurality of grinding discs (4) spaced apart from one another in the direction of the horizontal axis (6), each of the grinding discs (4) having a slot or an opening, The agitator mill (1) is provided with a driving body in the region between two grinding discs (4), the driving body circulating synchronously with the grinding discs (4) during grinding, and the driving body directly displaces the grinding bodies, preferably radially, in response to the circulation of the grinding bodies, thereby imparting a radially outward motion component to at least a portion of the grinding bodies that contact the driving body.

2. 2. The agitator mill (1) according to claim 1, characterized in that the driver comprises at least one portion having a non-circular surface shape relative to the horizontal axis (6) of the agitator shaft (3), the at least one portion forming a pulse-generating portion (7) that displaces the grinding bodies in response to the rotation of the driver.

3. 3. The agitator mill (1) according to claim 1 or 2, characterized in that the driver is a bushing (8) which engages on the agitator shaft (3) in the free area between the grinding discs (4), or which is integrally formed by the agitator shaft (3) in the free area, or which is an integral part protruding from the front side of at least one grinding disc (4), and a single bushing (8) is preferably located between two directly adjacent grinding discs (4).

4. 4. A stirring mill (1) according to any one of claims 1 to 3, characterized in that the bushing (8) has an initial shape of a body with a polygonal cross section, said body having at least a partially tapered portion (9) between its front sides (10), the cross section of which has a circumference smaller than the polygonal cross section of said initial shape.

5. 5. A stirred mill (1) according to claim 4, characterized in that the cross section of the tapered portion (9) is at least largely circular, said circular shape preferably having a constant diameter over the length of the tapered portion (9).

6. Agitator mill (1) according to any one of claims 1 to 5, characterized in that the transition (13) between each front side (10) and / or front portion (11) and the tapered portion (9) is inclined, preferably conically or spherically inclined.

7. 7. An agitator mill (1) according to any one of claims 1 to 6, characterized in that the tapered portion (9) of the bushing (8) is bordered against the pulse generating portion (7) by a curved surface so as not to form a pulse generating portion (7) even when in response to rotation of the bushing (8).

8. 8. The agitator mill (1) according to claim 1, characterized in that the bushing (8) has an inclined surface in the region of its tapered section (9), preferably in the transition region (13) between the tapered section (9) and the front side (10) and / or between the tapered section (9) and the front side (11), which is designed so that a circumferential movement of the agitator shaft (3) is forced onto the grinding bodies by the inclined surface, in particular by the rotation of the bushing (8), and in so doing the grinding bodies are preferably also pressed into the central region between two directly adjacent grinding discs (4).

9. 9. A stirring mill (1) according to any one of claims 1 to 8, characterized in that the bushing (8) is tapered in such a way that the length of its tapered portion (9) is at least 45% of the distance between two directly adjacent grinding discs (4), measured parallel to the horizontal axis (6) of the stirring shaft (3).

10. Agitator mill (1) according to any one of claims 1 to 9, characterized in that at least 45% of the bushing surface facing the grinding space (14) is free of pulse-generating parts (7).

11. An agitator mill (1) according to any one of claims 1 to 10, characterized in that the tapered portion of the bushing (8) is not provided with a pulse generating portion (7).

12. 12. The agitator mill (1) according to any one of claims 1 to 11, characterized in that the pulse generating portion (7) is arranged mostly or entirely in a region adjacent to the front of the grinding discs, said region preferably occupying not more than ¼ of the distance between two directly adjacent grinding discs (4), measured in the direction of the horizontal axis (6) of the agitator shaft (3).

13. 13. A stirring mill (1) according to any one of claims 1 to 12, characterized in that the grinding discs (4) have at least one, preferably several, openings through which the grinding bodies can reach from an intermediate space between two grinding discs (4) into an adjacent intermediate space between two grinding discs (4).

14. 14. The agitator mill (1) according to any one of claims 1 to 13, characterized in that a flow breaker (12) is arranged between the grinding discs (4), and the flow breaker (12) protrudes from the inner surface of the grinding vessel into the free area between two grinding discs (4), preferably directly above the tapered part of the bushing (8), ideally into its central area.

15. 15. A stirring mill (1) according to any one of claims 1 to 14, characterized in that the flow breakers (12) are arranged asymmetrically, preferably in the circumferential direction, i.e. in the intermediate space between two directly adjacent grinding discs (4), closer to one grinding disc (4) than to the other grinding disc (4).

16. a driver, preferably in the form of a bushing (8), arranged in the area between two adjacent grinding discs (4), a driving body that circulates synchronously with the grinding disc (4) during grinding, and that directly displaces the grinding bodies, preferably radially, in response to the circulation of the grinding bodies, thereby imparting a radially outward component of motion to at least a portion of the grinding bodies that contact the driving body.

17. A driver, preferably in the form of a bushing (8), according to claim 16, wherein the driver is a Driver, characterized in that it is designed according to the features of at least one of claims 2 to 15.

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