EP2905080A1 - Agitator ball mill - Google Patents

Abstract

An agitating ball mill comprises a grinding chamber (1), a stirring shaft (5) projecting into the grinding chamber (1), on which stirring elements (10, 20, 30) formed as paddle wheels are axially spaced from each other, and an inlet ( 6) for the supply of regrind and grinding media and an outlet (7) for removing the ground material. The stirring elements (10, 20, 30) are designed so that during operation they convey a mixture consisting of material to be milled or dispersed and grinding bodies through their interior away from the stirring shaft (5) to the outside. In the grinding chamber (1) are arranged with the agitator shaft (5) non-rotatably connected Rückförderorgane (17, 27, 37, 47, 57) which the mixture laterally next to and / or between the stirring members (10, 20, 30) inwardly to Promote stirrer shaft (5).

Description

The present invention relates to a stirred ball mill according to the independent claim.

An agitator ball mill of the generic type is eg in WO 2010/112274 described. The agitator ball mill described therein comprises a substantially cylindrical grinding chamber, which is delimited by a jacket and one inlet and one outlet end wall, and a rotatably mounted stirring shaft, on the inside of the grinding chamber paddle wheel-like, also referred to as accelerators stirring members are arranged axially mutually spaced , In the vicinity of the inlet-side end wall, an inlet for supplying ground material and grinding bodies is arranged and in the outlet-side end wall, an outlet for removing the ground Guts is provided, which is separated by a grinding medium-retaining separator screen from the grinding chamber. In operation, the agitator shaft and thus the non-rotatably connected stirrers are rotated by an external motor in rotation. Agitator ball mills of similar construction are, for example, in EP 0 627 262 and EP 2 272 591 described.

These agitator ball mills, equipped with paddle-wheel agitators, convey during the grinding and / or dispersing process a portion of the mixture formed from grinding media and the material to be ground and / or dispersed radially outwardly, whereupon at least a portion of the mixture is directed towards the stirring shaft and from there back into the Delivery chambers of the stirring elements flows or is sucked. This process is referred to below as Mahlkörperkreislauf.

In the known stirred ball mills of this type occurs under certain constellations the problem that during the grinding or dispersing only an insufficient part of the radially outwardly conveyed from grinding media and the mixture to be ground and / or to be dispersed formed Good direction agitator shaft and from there flows back into the conveying channels of the stirring or is sucked in. This occurs especially when the kinetic energy of the grinding media is so great that their inertial forces are greater than the drag forces of the material to be ground and / or dispersed. In this case, a separation between grinding media and the material to be ground and / or to be dispersed takes place, ie the material to be ground and / or dispersed is detected by the intended grinding body cycle, while the majority of the grinding media compresses towards the periphery of the grinding chamber. On the one hand, this can lead to the product flowing into the grinding chamber accumulating on the compacted grinding bodies and thus increasing the pressure in the grinding chamber until the grinding media layer locally bursts under the influence of the pressure forces and the pressure then spontaneously decreases again. This can lead to vibrations of the agitator ball mill. Another consequence of the accumulation of the media to the periphery of the grinding chamber may be a suboptimal milling result.

The present invention is an agitator ball mill of the generic type to be improved so that the grinding media can not or at most only accumulate to a greatly reduced extent at the periphery of the grinding chamber, but as completely entrained from being ground and / or to be dispersed Good and so Mahlkörperkreislauf be supplied.

The object underlying the invention is achieved according to the invention by an agitator ball mill, as specified by the features of the independent claim. Further advantageous aspects emerge from the features of the dependent claims.

The agitator ball mill according to the invention comprises a grinding chamber, a rotatably mounted agitating shaft projecting at least partially into the grinding chamber, on which stirring elements are axially spaced apart within the grinding chamber, and an inlet for supplying ground material and grinding bodies and an outlet for removing the ground material , Wherein the stirring members each have at least one delivery chamber and are formed so that they in operation from a to be milled or to be dispersed Good and grinding media existing mixture through its at least one delivery chamber through the agitator shaft away to the outside, and wherein in the grinding chamber with the agitator shaft rotatably connected Rückförderorgane are arranged, which promote the mixture laterally next to and / or between the Rührorganen inwardly to the agitator shaft during operation.

The term "through" in this context means that the material to be ground or to be dispersed is conveyed away from the agitator shaft into the delivery chamber, outward in the delivery chamber, and then out of the delivery chamber. The return conveyors produce a flow field directed inwardly toward the agitator shaft, which increases the drag forces of the material to be ground and / or dispersed. Grinding media, which come into contact with these Rückförderorganen receive a likewise directed inward to the agitator shaft pulse. Both support the maintenance of the desired Mahlkörperkreislaufs.

According to one aspect of the agitator ball mill according to the invention, the return means are arranged laterally on the stirring elements. "Laterally" means that the return devices are arranged on those sides of the stirring elements, which point in the direction of the axis of rotation of the agitator shaft (the axis of rotation of the agitator shaft is therefore perpendicular to these sides), for example, the Rückförderorgane of lateral end faces of the stirring elements from. According to a further aspect of the agitator ball mill according to the invention, the return-conveying elements are arranged at a distance laterally next to and / or between the stirring elements. Both aspects are structurally particularly favorable.

According to a further aspect of the agitator ball mill according to the invention, the return-conveying elements are arranged laterally on at least one separate (preferably disk-shaped) support which is connected in a rotationally fixed manner to the agitator shaft. As a result, the stirring elements and the return devices can be optimized and manufactured independently of each other.

According to a further aspect of the agitator ball mill according to the invention, the return means are designed as return feed vanes.

In this case, the stirring elements according to a further aspect may be formed as paddle wheels and having steering blades, which are employed obliquely inwardly from the outside in the direction of rotation of the stirring elements and are preferably curved in the direction of rotation of the stirring members, wherein the return blades against the direction of rotation of the stirring elements obliquely inwards are employed.

According to a further aspect of the agitator ball mill according to the invention, the return feed vanes are arranged in at least one return conveyor unit which is connected in a rotationally fixed manner to the agitator shaft and is designed as a paddle wheel.

According to a further aspect of the agitator ball mill according to the invention, the return feed vanes are curved in the direction of rotation.

In this case, the radius of curvature of the return flow blades can be, for example, 40% -70% of the outer diameter of the stirring elements.

According to a further aspect of the agitator ball mill according to the invention, the return feed vanes each have an inner end and an outer end, wherein the return feed vanes enclose at their inner end an angle with the circumferential direction at the location of the respective inner end, which is in the range of 5 ° to 30 ° ,

According to a further aspect of the agitator ball mill according to the invention, the stirring elements arranged on the agitator shaft are designed as single-chamber agitators and / or two-chamber agitators and each have an equal outer diameter, the distance between a one-chamber agitator and an adjacently disposed single chamber agitator or between a one-chamber stirrer and an adjacent two-chamber impeller in the range of 10% -20% of the outer diameter of the stirrers, and wherein the distance between a two-chamber -Rührorgan and an adjacently arranged two-chamber stirring member in the range of 30% - 40% of the outer diameter of the stirring elements. This further optimizes the media circulation.

According to a further independent concept of the invention, the agitating ball mill according to the invention comprises a grinding chamber, a rotatably mounted agitating shaft projecting at least partially into the grinding chamber, on which stirring elements are axially spaced apart within the grinding chamber, and an inlet for supplying ground material and grinding bodies and an outlet for removing the ground material, wherein the stirring elements each have at least one delivery chamber and are designed such that during operation they convey a mixture consisting of material to be milled or dispersed and grinding bodies outwardly away from the agitator shaft through their at least one delivery chamber, wherein the arranged on the agitator stirrer agitators are designed as a one-chamber stirrers and / or as a two-chamber stirring members and each having an equal outer diameter, wherein the distance between a one-chamber stirrer and an adjacent angeor dneten one-chamber agitator or between a one-chamber stirrer and an adjacently arranged two-chamber agitator in the range of 10% - 20% of the outer diameter of the stirrers, and wherein the distance between a two-chamber stirrer and an adjacently arranged two-chamber stirring element in the range of 30% - 40% of the outer diameter of the stirring elements.

According to this inventive concept, the problem underlying the invention of the accumulation of grinding media in the Mahlkammerperipherie is solved by the special mutual arrangement of Rührorgane, whereby the grinding media entrained to be ground and / or to be dispersed Good and fed to the grinding body cycle.

The following further aspects are to be understood in combination with the idea of the invention just described with the special distances between the stirring elements.

According to one aspect, in the grinding chamber with the agitator shaft rotatably connected Rückförderorgane are arranged, which promote the mixture laterally adjacent to and / or between the Rührorganen inwardly to the agitator shaft during operation. These additional return devices further improve the media circulation.

According to a further aspect, the return devices are arranged laterally on the stirring elements. According to a further aspect, the return means are arranged at a distance laterally next to and / or between the stirring members. According to a further aspect, the return-conveying elements are arranged laterally on at least one separate (preferably disk-shaped) support which is connected in a rotationally fixed manner to the agitator shaft.

According to a further aspect, the return devices are designed as return feed vanes.

According to a further aspect, the stirring elements are formed as paddle wheels and have steering vanes, which are employed obliquely inwardly in the direction of rotation of the stirring elements inwardly and are preferably formed curved in the direction of rotation of the stirring elements, wherein the return blades from the outside against the direction of rotation of the stirring elements obliquely inwards are employed.

According to a further aspect, the return-conveying blades are arranged in at least one return-conveying unit which is connected in a rotationally fixed manner to the agitating shaft and designed as a paddle wheel.

According to a further aspect, the return feed vanes are curved in the direction of rotation. In this case, the radius of curvature of the return flow blades can be, for example, 40% -70% of the outer diameter of the stirring elements.

According to a further aspect, the return feed vanes each have an inner end and an outer end, wherein the return feed vanes enclose at their respective inner ends with the circumferential direction at the location of the respective inner end an angle which is in the range of 5 ° to 30 °.

Fig. 1

einen Axialschnitt durch ein erstes Ausführungsbeispiel der erfindungsgemässen Rührwerkskugelmühle;

Fig. 2-4

je eine perspektivische Schrägansicht von drei Acceleratoren;

Fig. 5

eine perspektivische Schrägansicht eines in der Rührwerkskugelmühle der Fig. 1 eingesetzten Accelerators;

Fig. 6

eine Skizze zur Verdeutlichung der gegenseitigen Positionierung diverser Elemente der Rührwerkskugelmühle;

Fig. 7

einen Axialschnitt durch ein zweites Ausführungsbeispiel der erfindungsgemässen Rührwerkskugelmühle;

Fig. 8

eine perspektivische Schrägansicht einer Förderscheibe der Rührwerkskugelmühle der Fig. 7;

Fig. 9

einen Axialschnitt durch ein drittes Ausführungsbeispiel der erfindungsgemässen Rührwerkskugelmühle;

Fig. 10

eine perspektivische Schrägansicht von auf der Rührwelle der Rührwerkskugelmühle der Fig. 9 angeordneten Elementen und

Fig. 11-13

je einen Axialschnitt durch drei weitere Ausführungsbeispiele der erfindungsgemässen Rührwerkskugelmühle.

Further advantageous aspects emerge from the following description of exemplary embodiments of the agitator ball mill according to the invention with the aid of the drawing. Show it:

Fig. 1

an axial section through a first embodiment of the inventive agitator ball mill;

Fig. 2-4

one perspective oblique view of three accelerators;

Fig. 5

an oblique perspective view of one in the agitator ball mill of Fig. 1 used accelerators;

Fig. 6

a sketch to illustrate the mutual positioning of various elements of the agitator ball mill;

Fig. 7

an axial section through a second embodiment of the inventive agitator ball mill;

Fig. 8

an oblique perspective view of a conveyor disc of the agitator ball mill of Fig. 7 ;

Fig. 9

an axial section through a third embodiment of the inventive agitator ball mill;

Fig. 10

a perspective oblique view of the agitator shaft of the agitator ball mill of Fig. 9 arranged elements and

Fig. 11-13

each an axial section through three further embodiments of the inventive agitator ball mill.

The following definition applies to the following description: If reference signs are indicated in a figure for the purpose of clarity of drawing, they are indicated immediately associated description part not mentioned, reference is made to the explanation in the preceding or following description parts. Conversely, less relevant reference numerals are not included in all figures to avoid overcharging graphic for the immediate understanding. For this purpose, reference is made to the other figures. Furthermore, the terms upstream and downstream with respect to the general direction of Mahlgutstroms be understood by the agitator ball mill, ie from the Mahlguteinlass to Mahlgutauslass. In the following, "accelerators" are described as "stirring elements", so that the terms are used synonymously, although in principle the stirring elements are not limited to the accelerators described.

Like the sectional view of the Fig. 1 shows, the agitator ball mill according to the invention comprises a substantially cylindrical grinding chamber 1, which is bounded by a jacket 2 and each one inlet and one outlet-side end wall 3 and 4 respectively. By the inlet-side end wall 3, an externally or in the end wall rotatably mounted agitator shaft 5 is carried out on the inside of the grinding chamber 1, three paddle wheel-like agitators or accelerators 10, 20 and 30 are arranged axially spaced from each other. The accelerators 10, 20 and 30 are rotatably connected to the agitator shaft and are rotationally driven during operation thereof. In the vicinity of the inlet-side end wall 3, an inlet 6 for the supply of ground material and grinding media is arranged and in the outlet-side end wall 4, an outlet 7 is provided for removing the ground material, the outlet 7 by a the grinding media retaining separator screen 8 of the Grinding chamber 1 is separated. In the outlet-side end wall 4, an open towards the interior of the grinding chamber 1 annular channel 9 is formed. In operation, the agitator shaft and thus the rotatably connected to her stirring members or accelerators are rotated by an external motor, not shown in rotation.

The basic structure of the three accelerators 10, 20 and 30 is best from the partially cut perspective oblique views of Figures 2-4 recognizable. In this case, the essential elements for the invention are not yet shown, these will be discussed below.

The accelerator 10 hereinafter referred to as a single-chamber accelerator comprises two parallel annular disks 11 and 12, between which are arranged curved steering vanes 14 which extend obliquely inwards from the outer circumference of the disks in the direction of rotation P. The disk 12 is provided close to the stirring shaft with a series of openings 15 through which the mixture of grinding stock and grinding media can enter the accelerator 10. The openings 15 can also be guided at an angle of 40 ° - 50 ° to Rührwellenachse or slotted. The disc 11 has a diameter in the relatively large central opening 16 ( Fig. 1 ) serving the same purpose (entry of the mixture into the accelerator). The two annular disks 11 and 12 define between them a delivery chamber and together with the steering vanes 14 form a single-chamber impeller, which upon rotation of the agitator shaft 5 (FIG. Fig. 1 ) and thus of the accelerator 10 in the direction of rotation P, the mixture in the delivery chamber of grinding stock and grinding media to the outside in the direction of the periphery (shell 2) of the grinding chamber 1 promotes.

The accelerator 20 differs from the accelerator 10 by training as a two-chamber accelerator. It comprises three parallel annular discs 21, 22 and 23, between each of which curved steering vanes 24 are arranged, which extend obliquely inwardly from the outer circumference of the discs in the direction of rotation P. The middle disc 23 forms the supporting element and is rotatably mounted on the agitator shaft 5. The middle disc 23 is further provided Rührwellennah with a series of openings 25 through which the mixture of regrind and grinding media can pass. The openings 25 can also be guided at an angle of 40 ° - 50 ° to Rührwellenachse or slotted. The two outer discs 21 and 22 each have a diameter in the relatively large central opening 26 through which the mixture of grinding stock and grinding media can enter the accelerator 20. The three annular disks 21, 22, 23 define between them two delivery chambers and together with the steering vanes 24 form a two-chamber impeller, which upon rotation of the agitator shaft 5 (FIGS. Fig. 1 ) and thus of the two-chamber accelerator 20 in the direction of rotation P located in the delivery chambers mixture of regrind and Grinding bodies to the outside in the direction of the periphery (shell 2) of the grinding chamber 1 promotes.

The accelerator 30, which is referred to below as a two-chamber end accelerator, is in principle designed in the same way as the two-chamber accelerator 20. It comprises two annular outer disks 31 and 32 and a middle disk 33, between each of which curved steering blades 34 are arranged are that extend obliquely inward from the outer circumference of the discs in the direction of rotation P. The two-chamber end accelerator 30 is attached to the free end of the agitator shaft 5, with its central disc 33 screwed to the end of the agitator shaft. Alternatively, the middle disc 33 could also be formed similar to the middle disc 23 of the accelerator 20 and mounted on the stirrer shaft. The middle disc 33 is again provided with a series of openings 35 close to the stirring shaft, and the two outer discs 31 and 32 each have a diameter opening which is relatively large in diameter. The openings 35 can also be guided at an angle of 40 ° - 50 ° to the stirrer shaft axis or slotted. The three discs 31, 32, 33 define between them two delivery chambers and form together with the steering vanes 34 again a two-chamber paddle wheel, although the guide vanes between the central disc 33 and the outlet 7 facing outer disc 33 in the axial direction wider are the steering vanes between the middle disc 33 and the other outer disc 31. The two-chamber end accelerator 30 engages with its wider steering paddles the separator screen 8 Fig. 1 ).

In the Fig. 1 and also in the FIGS. 7 and 11-13 are some typical mass of the grinding chamber 1 and the accelerators 10, 20 and 30 registered. The inner diameter of the grinding chamber 1 or of the jacket 2 is denoted by D. D _a is the external diameter (normally the same for all accelerators) of the accelerators 10, 20 and 30. It is typically 75% -90% of the grinding chamber diameter D. The mass d _i denotes the diameter (usually the same for all accelerators) of the central openings 16, 26 and 36 of the accelerators 10, 20 and 30. It is typically 70% -80%. of the outer diameter d _a . With c1, c2 and c3 are measured in the axial direction Total widths of the accelerators 10, 20 and 30 are designated. The dimension k designates the delivery chamber widths of the accelerators 10, 20 and 30 defined by the inner spacing of two respective adjacent disks 11, 12 and 21, 23 and 23, 22 and 31, 33 of the accelerators 10, 20 and 30. They are typically 5% - 15% of the outer diameter d _a . With a, the axial distance of the inlet-side end wall 3 nearest accelerator is designated by the end wall. It is typically 10% - 15% of the outer diameter d _a . The masses b1 and b2 denote the axial distances between adjacent accelerators. The distances b1 and b2 between the accelerators 10, 20 and 30 will be discussed in more detail below.

During operation of the stirred ball mill, the mixture consisting of material to be milled or dispersed occurs and enters the accelerators or stirrers 10, 20 and 30 through the openings near the stirrer shaft 16 or 26 or 36 and passes through their delivery chamber or delivery chambers from the accelerators or stirrers out to the outside in the peripheral or jacket-near area of the grinding chamber 1 promoted. From there, a part of the mixture flows in the already mentioned Mahlkörperkreislauf laterally next to and between the accelerators back into the Rührwellennahen area and is sucked from there back into the accelerators. The ground or dispersed material is discharged through the outlet 7 from the grinding chamber. The openings 15 and 25 or 35 serve to compensate for an axial Mahlkörperfall. In fact, during operation, some of the grinding media downstream are entrained (from the inlet to the outlet) from one delivery chamber to the next. The openings 15 and 25 and 25 have by their slope the property to promote the grinding media upstream and compensate in this way the Mahlköperfall.

As far as corresponds to the inventive agitator ball mill in structure and operation of the prior art, as for example, by the already mentioned above WO 2010/112274 A1 . EP 0 627 262 B1 , or EP 2 272 591 B 1 is represented. The expert therefore needs no further explanation so far. In order to counteract the problem underlying the invention of the grinding media compaction in the mantel near the grinding chamber, according to a first inventive concept in the grinding chamber 1 special return organs are arranged, which ensure that the said mixture with as many of the grinding media contained therein from the mantle near area in the Stirring close to the grinding chamber is fed back.

In the embodiment of the stirred ball mill according to Fig. 1 these return conveyors are arranged laterally on one or both of the outer disks 11 or 21 and 22 or 31 of the accelerators 10, 20 and 30 (they stand from the respective lateral end faces of the outer disks 11 and 21 in the direction of the axis of rotation of the agitator shaft ab) and are denoted there by 17, 27 and 37. The detailed representation of the Fig. 5 which the accelerator 20 of the Fig. 1 shows isolated in perspective oblique view, can clearly recognize the shape and arrangement of the return conveyor 27.

At each of the two outer annular discs 21 and 22 of the accelerator 20 are each four in the direction of rotation P of the accelerator 20 curved return conveyors in the form of return feed vanes 27 are arranged. The return feed vanes 27 are in principle similar to the steering vanes 24 of the accelerator 20, but employed opposite in relation to the direction of rotation so that they unfold a conveying effect in reverse direction upon rotation of the accelerator 20 in the direction of rotation P, ie from outside to inside in the direction towards the agitator shaft. The number of return feed vanes 27 per side of the accelerator 20 may also be less than or greater than four, for example, up to twenty.

In the accelerators 10 and 30, the return conveyors are also formed as return feed vanes 17 and 37 and arranged the same as in the accelerator 20, but here in the embodiment only on one side of the accelerator 10 and 30. The number of return feed vanes can also be smaller or larger be four and for example also up to twenty.

The height h of the return feed vanes 17, 27 and 37 measured in the axial direction is approximately 5% to 15% of the outer diameter d _{a of} the accelerators 10, 20 and 30 (FIG. Fig. 1 ). The radius of curvature r _{s of} the return feed vanes 17, 27 and 37 is preferably about 40% - 70% of the outer diameter d _a ( Fig. 1 ) of the accelerators 10, 20 and 30 ( Fig. 6 ). The angle of attack α enclosed between the circumferential direction t _u at the location of the inner ends 27i of the return feed vanes 17, 27 and 37 and the tangent t _s at the inner ends of the return feed vanes is approximately 5 ° -30 ° (FIG. Fig. 6 ).

The return feed vanes 17, 27 and 37, on the one hand, generate a flow field directed inwards towards the stirrer shaft, which increases the drag forces of the material to be ground and / or to be dispersed. On the other hand, grinding bodies which come into contact with these return-conveying blades also receive an impulse directed inwards towards the stirring shaft. Both support the maintenance of the desired Mahlkörperkreislaufs.

In Fig. 7 is a second embodiment of the inventive agitator ball mill shown. A first difference compared to the embodiment of Fig. 1 is that on the agitator 5, instead of the single-chamber accelerator 10, a further two-chamber accelerator 20 is arranged on the agitator shaft. In contrast to the embodiment of Fig. 1 but here the return devices are not arranged on the stirrers or accelerators 20 and 30, but are designed as separate return conveyor units 40 and preferably arranged centrally between two accelerators.

Fig. 8 shows the formation of such a return unit 40 in a perspective oblique view. It consists of a disc-shaped carrier 41 and four each arranged on both sides of the carrier return conveyor blades 47. The carrier 41 is on the agitator shaft 5 (FIG. Fig. 6 ) and rotatably connected thereto. In addition, the carrier 41 in the Rührwellennahen area a number of openings 45 through which the millbase / grinding media mixture can flow through. The openings 45 can also be performed at an angle of 40 ° - 50 ° to Rührwellenachse or slotted. Arrangement, training and number the return feed vanes 47 are the same as in connection with Fig. 5 and Fig. 6 therefore, they do not explain and need no further explanation.

Of course, it is also possible to partially combine the two described embodiments and to provide both return flow blades on the accelerators and one or more independent return flow units.

The FIGS. 9 and 10 show a third embodiment of the inventive agitator ball mill. Here, as in the embodiment of Fig. 7 in the grinding chamber 1 on the stirring shaft 5, two two-chamber accelerators 20 and a two-chamber-end accelerator 30 are arranged, all of which are also not equipped with return feed vanes. In contrast to the first two exemplary embodiments, in this embodiment, in each case, a return conveyor unit 50 designed as a two-chamber impeller is arranged between two adjacent ones of the three accelerators. The return conveyor units 50 are in principle the same design as the Schaufelradartigen two-chamber accelerators 20. They therefore have three annular discs 51, 52 and 53 and in each case between these curved and obliquely inwardly employed return conveyor blades 57 on. However, the setting direction of the return feed vanes 57 is opposite to that of the steering vanes 24 and 34 in the accelerators 20 and 30 (ie, counter to the direction of rotation obliquely inwards), so that results in the same direction of rotation an oppositely directed conveying effect. The middle disc 53 is fixedly mounted on the agitator shaft 5 and has in its Rührwellennahen area a number of through openings, not shown. The openings can also be guided at an angle of 40 ° - 50 ° to Rührwellenachse or slotted. The two outer discs 51 and 52 each have a diameter in the relatively large central opening 56. The discs 51, 53 and the discs 52, 53 each define a delivery chamber, a total of two delivery chambers, and together with the return feeders 57 form a two-chamber paddle wheel analogous to the two-chamber accelerator 20, but with conveying direction from outside to inside instead of inside out. In principle, the return conveyor unit 50 could also be realized by a two-chamber accelerator 20 mounted on the agitator shaft 5 "oriented upside down". With regard to the shape, arrangement and number of return feed vanes 57, the same considerations apply as stated in connection with the first two embodiments.

The return conveyor units 50 can be arranged between the individual accelerators at an axial distance from the accelerators or preferably completely between the accelerators, which then results in a particularly compact design. Of course, it is in principle also possible to form a paddlewheel-like one-chamber return conveyor unit analogous to the accelerator 10.

In the FIGS. 11-13 three further embodiments of the inventive agitator mill are each shown in an axial section. Each of the three embodiments comprises a substantially cylindrical grinding chamber 1 which is delimited by a jacket 2 and an inlet and an outlet-side end wall 3 and 4, respectively. By means of the inlet-side end wall 3, an agitator shaft 5 which is rotatably mounted externally or in the end wall is carried out, on which agitator-type stirring elements or accelerators are arranged axially at a mutual distance within the grinding chamber 1. The accelerators are rotatably connected to the agitator shaft and are rotationally driven during operation. In the vicinity of the inlet-side end wall 3, an inlet 6 for supplying grinding stock and grinding media is arranged, and in the outlet-side end wall 4 is provided an outlet 7 for removing the ground product, which is separated from the grinding chamber 1 by a grinding medium-retaining separator screen 8 , In the outlet-side end wall 4, an open towards the interior of the grinding chamber 1 annular channel 9 is formed.

The agitator ball mill of Fig. 11 corresponds in principle to that of Fig. 7 and comprises two two-chamber accelerators 20 and a two-chamber end accelerator 30. The agitator ball mill of Fig. 12 includes three single-chamber accelerators 10 and a two-chamber final accelerator 30. The agitator ball mill of Fig. 13 corresponds in principle to that of Fig. 1 and includes a single-chamber accelerator 10, a two-chamber accelerator 20, and a two-chamber end accelerator 30. The accelerators 10, 20, and 30 are as in FIG Related to the Figures 2-4 described trained and therefore require no further explanation.

In contrast to the embodiments of the FIGS. 1 . 7 and 9 are in the three embodiments of the FIGS. 11-13 the agitator ball mill no return devices available. The problem of grinding media compaction in the region near the shell of the grinding chamber is solved in these embodiments according to a second independent inventive idea that constructive conditions are created under which the grinding media entrained by the material to be ground and / or to be dispersed and so the Mahlkörperkreislauf supplied. These conditions are met if the free volume defined by the delivery chamber width k within the accelerators is in a certain ratio with the volume defined by the distance b1 or b2 between any two adjacent accelerators. The ratio is chosen so that the distance traveled by the grinding media is so long that they can deliver sufficient kinetic energy on their way, so that the resulting inertial forces are less than the drag forces of the material to be ground and / or to be dispersed , On the other hand, this "calming distance" is chosen to be sufficiently short so that the kinetic energy maintains a sufficiently high level in order to maintain the desired intensive mechanical stress of the material to be ground and / or dispersed.

The required ratio between the defined by the channel width k free volume within an accelerator to the volume defined by the distance between two adjacent accelerators is realized according to the invention by a special dimensioning of the distances b1 and b2 between the accelerators.

In the embodiment of Fig. 11 The distances b2 between the two two-chamber accelerators 20 and between the middle two-chamber accelerator 20 and the two-chamber end accelerator 30 in the range of 30% - 40% of the outer diameter d _{a of} the accelerators 20th and 30.

In the embodiment of Fig. 12 The distances b1 between each two of the one-chamber accelerators 10 and the distance b1 between the third single-chamber accelerator 10 and the two-chamber end accelerator 30 are in the range of 10% - 20% of the outer diameter d _a Accelerators 10 and 30.

In the embodiment of Fig. 13 are the distance b1 between the one-chamber accelerator 10 and the adjacent two-chamber accelerator 20 in the range of 10% - 20% of the outer diameter d _{a of} the accelerators 10, 20 and 30 and the distance b2 between the two-chamber -Accelerator 20 and the two-chamber-end accelerator 30 in the range of 30% - 40% of the outer diameter d _{a of} the accelerators 10, 20 and 30.

1. 1. Der Abstand b1 zwischen einem Ein-Kammer-Accelerator 10 und einem benachbarten Ein-Kammer-Accelerator 10 oder zwischen einem Ein-Kammer-Accelerator 10 und einem benachbarten Zwei-Kammer-Accelerator 20 oder 30 im Bereich von 10% - 20% des äusseren Durchmessers d_a der Acceleratoren.
2. 2. Der Abstand b2 zwischen zwei benachbarten Zwei-Kammer-Acceleratoren 20 oder 30 liegt im Bereich von 30% - 40% des äusseren Durchmessers d_a der Acceleratoren.

Generally, the ratio between the free volume defined by the delivery chamber width k within an accelerator to the volume defined by the distances b1 and b2 between each two adjacent accelerators is achieved by the following design rule for the establishment of the abovementioned conditions:

1. 1. The distance b1 between a one-chamber accelerator 10 and an adjacent one-chamber accelerator 10 or between a one-chamber accelerator 10 and an adjacent two-chamber accelerator 20 or 30 in the range of 10% - 20% the outer diameter d _{a of} the accelerators.
2. 2. The distance b2 between two adjacent two-chamber accelerators 20 or 30 is in the range of 30% - 40% of the outer diameter d _{a of} the accelerators.

The described dimensioning of the distances between the accelerators 10, 20 and 30 can also be advantageous in the embodiments equipped with return means according to the FIGS. 1 and 7 be applied. To clarify this combination possibility, the distances b1 and b2 are also entered in these figures. The optimized enlargement of the distances between the accelerators according to the above design rule leads in combination with the Use of recirculation means to further improve the grinding media cycle.

The invention has been explained above with reference to embodiments, but should not be limited to these embodiments. Rather, numerous modifications are conceivable for those skilled in the art without departing from the teaching of the invention. Thus, for example, more than three stirring elements may be provided in the grinding chamber with or arranged therebetween return conveyor organs. The scope of protection is therefore defined by the following claims.

Claims (11)

Agitator ball mill with a grinding chamber (1), an at least partially in the grinding chamber (1) projecting, rotatably mounted agitator shaft (5) on which within the grinding chamber (1) stirring members (10, 20, 30) are axially spaced from each other, and an inlet (6) for supplying ground material and grinding bodies and an outlet (7) for removing the ground material, wherein the stirring elements (10, 20, 30) each have at least one delivery chamber and are designed such that they enter during operation from mixture to milling or to be dispersed Good and Mahlkörpern existing mixture through their at least one delivery chamber through the agitator shaft away to the outside, and in the grinding chamber (1) with the agitator shaft (5) non-rotatably connected Rückförderorgane (17, 27, 37; 47, 57) are arranged, which in operation promote the mixture laterally next to and / or between the stirring members (10, 20, 30) inwardly toward the agitator shaft (5). Agitator ball mill according to claim 1, wherein the return means (17, 27, 37) are arranged laterally on the stirring elements (10, 20, 30). Agitator ball mill according to one of the preceding claims, wherein the return means (47) are arranged at a distance laterally next to and / or between the stirring members (10, 20, 30). Agitator ball mill according to claim 3, wherein the return-conveying elements (47) are arranged laterally on at least one separate carrier (41) connected in a rotationally fixed manner to the agitator shaft (5). Agitator ball mill according to one of the preceding claims, wherein the return means are designed as return feed vanes (17, 27, 37; 47; 57). Agitator ball mill according to claim 5, wherein the stirring members (10, 20, 30) are formed as paddle wheels and steering vanes (14, 24, 34), which are employed obliquely inwardly from the outside in the direction of rotation of the stirring members and are preferably formed curved in the direction of rotation of the stirring elements, and wherein the return feed vanes (17, 27, 37, 47, 57) are made obliquely from the outside against the direction of rotation of the stirring elements inwardly. Agitator ball mill according to claim 5 or 6, wherein the return-conveying blades (57) are arranged in at least one return-conveying unit (50) connected in a rotationally fixed manner to the stirring shaft (5) and designed as a paddle wheel. Agitator ball mill according to one of claims 5 to 7, wherein the return feed vanes (17, 27, 37; 47; 57) are curved in the direction of rotation. Agitator ball mill according to claim 8, wherein the stirring members (10, 20, 30) have an outer diameter (d _a ) and the radius of curvature of the return feed vanes (17, 27, 37; 47; 57) is 40% -70% of the outer diameter (d _a ) of the stirring members (10, 20, 30). An agitating ball mill according to any one of claims 5 to 9, wherein said return blades (17, 27, 37; 47; 57) each have an inner end and an outer end, said return blades forming an angle (α) at their respective inner end (27i) the circumferential direction (t _u ) at the location of the respective inner end (27i) include, which is in the range of 5 ° - 30 °. Agitator ball mill according to one of the preceding claims, wherein the stirrer shafts (5) arranged stirrers are designed as single-chamber agitator (10) and / or as a two-chamber stirring members (20, 30) and each have an equal outer diameter ( d _a ), wherein the distance (b1) between a one-chamber stirring element (10) and an adjacently arranged single-chamber stirring element or between a one-chamber stirring element and an adjacently arranged two-chamber stirring element (10, 20, 30) in the range of 10% - 20% of the outer diameter (d _a ) of the stirring elements, and wherein the distance (b2) between a two-chamber stirring member (20, 30) and an adjacently arranged two-chamber Agitator (20, 30) in the range of 30% - 40% of the outer diameter (d _a ) of the stirring elements is.

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