DE102018122395A1 - Agitator shaft for an agitator ball mill, agitator ball mill and method for producing an agitator shaft for an agitator ball mill - Google Patents

Abstract

The invention relates to an agitator shaft for an agitator ball mill, the agitator shaft having a longitudinal axis and an outer circumferential surface equipped with agitator elements, the agitator shaft being formed in one piece with the agitator elements and consisting of a ceramic material.

Description

The present invention relates to an agitator shaft for an agitator ball mill, an agitator ball mill and a method for producing an agitator shaft for an agitator ball mill according to the features of the independent claims.

State of the art

The invention relates to an agitator ball mill, in particular an agitator for an agitator ball mill. The agitator ball mill is a device for coarse, fine and very fine comminution or homogenization of regrind. An agitator ball mill consists of a vertically or horizontally arranged, mostly approximately cylindrical grinding container, which is filled to 70% to 90% with auxiliary grinding media. In the case of agitator ball mills, the grinding container is usually stored stationary. Many conventionally known mills are filled through a central opening in one of the end walls. Alternatively, the filling can also be done directly via the grinding cylinder. The product to be ground flows continuously during the grinding process from a product inlet axially through the grinding chamber to a product outlet. The suspended solids are crushed or dispersed between the grinding media by impact and shear forces. The grinding auxiliary bodies are then separated from the product stream in an outlet area. The discharge depends on the design and is carried out, for example, through a sieve at the end of the mill.

The agitator is usually formed by an agitator shaft which serves to rotate agitator elements in the form of disks or radially protruding pins, in particular to deagglomerate and comminute solids of the material to be ground, which are distributed in liquid. The agitator shaft is usually driven by a motor. Disk stirrers with a plurality of grinding disks arranged on a stirrer shaft are used in particular as suitable stirring elements. The grinding disks are usually circular and can be provided with through openings. The product flow is ensured in particular via the passage opening.

An annular grinding gap is formed between the inside of the grinding cylinder and the agitator, in which the grinding stock to be comminuted is located when the agitator ball mill is in operation. The agitator is driven in rotation and thus loads the material to be ground within the grinding gap, as a result of which it is comminuted, which is supported on the one hand by the auxiliary grinding bodies and on the other hand by the stirring elements of the agitator. In particular, the material to be ground and the auxiliary grinding bodies are moved intensively by means of a stirring shaft. The solid particles of the ground material are crushed by impact, pressure, shear and friction.

The agitator shafts or agitators preferably consist of an abrasion-resistant material, in particular of a metal or a ceramic material, for example describes WO 2000/054884 A an agitator ball mill in which the agitator, in particular the disk-shaped stirring elements, consists of a ceramic material. The DE 2626757 A1 discloses an agitator propeller constructed so that only relatively simple and inexpensive parts are subject to wear and that these parts are easily replaceable. Where it is economically feasible, these simple parts are made from a particularly abrasion-resistant material, such as ceramic.

Many processes, chemical, mechanical or other, run with the generation of process heat, which can have a negative impact on the process itself or the raw materials used, for example because the substances involved in the process are temperature-sensitive or the temperature change affects the process speed and thus orderly process control difficult. For this reason, it is common to stabilize a process flow, for example by dissipating the process heat generated by means of suitable cooling devices or processes. Processes running in containers are usually tempered via the container wall, for example by cooling or hot water pipes running on the wall or by guiding a further outer container that is radially spaced from the first container so that there is a gap between the two containers Forms a cavity through which a fluid flow, which can be a hot water flow or a coolant flow, can be conducted to transport the process heat.

Heat is also generated during the grinding process. Depending on the product, this heat must be dissipated or heat generation must be prevented. The problem exists particularly with agitator ball mills with a large grinding volume or when a higher power input is desired. For cooling during the grinding process, it is provided, for example, to design the grinding cylinder to be coolable. For example, the published specification describes DE 3614721 A1 the equipment of the grinding container with a cooling jacket as known prior art. This document also discloses that the agitator rotor can also be provided with at least one cooling channel on its circumference. A grinding container with a cooling jacket is still in the published patent application WO 2007/042059 A1 shown. Furthermore, the agitator mill described in this document an inner stator, which can also be cooled. The agitator is cup-shaped and comprises an annular cylindrical rotor.

As already in connection with the DE 3614721 A1 mentioned, cooling can alternatively or additionally also be implemented via the agitator rotor. The disclosure DE 3015631 A1 describes an agitator consisting of an inner and an outer cylinder, between which an annular cooling space is formed, wherein for cooling, a coolant-supplying pipeline is arranged axially parallel within the cooling space, which is connected to a supply pipe for coolant.

Another coolable stirrer shaft is described in the patent DE 10241924 B3 discloses, for cooling tubular material is used in various cross-sectional shapes, within which an inner tube is arranged, which extends over almost the entire length, the interior of the tube is connected to the coolant inlet and the outer space is connected to the coolant outlet.

From a certain size, stirrer shafts or ceramic stirrers must be made up of several components. A lot of grinding work is necessary to produce the individual parts to each other, which means that the costs are very high due to the necessary working time. In addition, when the agitator shaft is assembled from a plurality of parts, so-called dead spaces arise, in which ground material and / or auxiliary grinding bodies can become lodged and thus contaminate the machine room. Such multi-part ceramic stirrer shafts are also very sensitive to breakage, especially during assembly, disassembly, cleaning and maintenance. In addition, it has so far not been possible to produce ceramic rotors with cooling.

description

The object of the invention is to produce an agitator shaft for an agitator ball mill easily and inexpensively, in particular a coolable agitator shaft for use in high-performance agitator ball mills.

The above object is achieved by an agitator shaft for an agitator ball mill, an agitator ball mill and a method for producing an agitator shaft for an agitator ball mill, which comprise the features in the independent patent claims. Further advantageous configurations are described by the subclaims.

The agitator ball mill is used for processing and in particular comminuting regrind with the aid of auxiliary grinding bodies and has a grinding container with a grinding material inlet and a product outlet, to which an agitator is assigned, which is arranged at least partially within the grinding container.

The agitator comprises a drive, an agitator shaft arranged on the drive and rotating in one direction of rotation and at least one agitator element arranged on the agitator shaft. The stirring shaft has a preferably cylindrical base body with a longitudinal axis, at least one stirring element, preferably a plurality of stirring elements, being / are arranged on the base body. In particular, the agitator shaft has an outer lateral surface equipped with agitating elements. The longitudinal axis of the agitator shaft usually coincides with the longitudinal axis of the grinding container. The drive is usually arranged outside the grinding container and connected to the stirring shaft arranged inside the grinding container via a drive shaft penetrating the container wall.

The grinding container is preferably cylindrical and arranged lying or standing, so that the agitator shaft is arranged lying or standing accordingly. The grinding container can also have a different shape and, for example, be designed in the shape of a truncated cone. In this case, the agitator shaft is preferably also frustoconical.

The at least one stirring element is designed, for example, as a cam, which preferably extends approximately radially away from the stirring shaft in the direction of an inner side of the grinding container of the stirred ball mill.

An annular grinding gap is formed between the outer lateral surface of the agitator shaft and the inner lateral surface of the grinding container, in which there is a mixture of grinding stock and auxiliary grinding bodies. Due to the rotation of the agitator shaft, the ground material is crushed within the grinding gap due to the stress, for example, by particles colliding with one another, by shear forces, etc. The stirring elements support this by causing an additional energy input, in particular on the auxiliary grinding bodies, through the stirring elements.

The agitator shaft with the agitator elements is formed and manufactured in one piece and preferably consists of a ceramic material. The stirrer shaft is particularly preferably made from silicon carbide (SiC), from silicon carbide with free silicon (SiSiC), from silicon nitride, from zirconium oxide or from mixed ceramics. Silicon carbide ceramics have a high wear resistance, low thermal shock sensitivity, low Thermal expansion, high thermal conductivity, good resistance to acids and alkalis and are also easy and keep their positive properties up to temperatures above 1400 ° C. In addition, silicon carbide is toxicologically safe and can therefore also be used in the food sector. Silicon nitride has a reduced hardness in comparison to silicon carbide, but a sintering process can cause a recrystallization of the β-silicon nitride crystals, which leads to increased fracture toughness of the material. The high fracture toughness in combination with small defect sizes gives silicon nitride one of the highest strengths among the engineering ceramic materials. The combination of high strength, low coefficient of thermal expansion and a relatively small modulus of elasticity make silicon nitride ceramic particularly suitable for components subject to thermal shock. In contrast to other ceramic materials, zirconium oxide has a very high resistance to the spread of cracks. In addition, zirconium oxide ceramic has a very high thermal expansion and is therefore often chosen when realizing connections between ceramic and steel.

The stirrer shaft with the stirrer elements is particularly preferably produced by means of a 3D printing process. In this way it is possible to produce a component with internal cavities that can be manufactured using conventional methods such as injection molding or the like. would not be producible in one process step without further post-processing, for example without subsequent drilling of holes or the like. However, it is now possible to easily and inexpensively form at least one integrated cooling channel within the agitator shaft. It is preferably provided that the cooling channel extends at least in regions parallel to the longitudinal axis of the agitator shaft. According to one embodiment, it is provided that the at least one cooling duct is meandering, for example at least two regions of the cooling duct each extend parallel to the longitudinal axis of the agitator shaft, a deflection region being formed between the two regions running in parallel.

According to one embodiment of the invention, two parallel areas, through which coolant flows in opposite flow directions, are located on a common radial of the agitator shaft. Countercurrent cooling of the agitator shaft is thereby achieved. In particular, the coolant is guided near the longitudinal axis of the agitator shaft from the regrind inlet side to the product outlet side. The coolant is returned from the product outlet side to the regrind inlet side within the agitator shaft in a region adjacent to the outer surface of the agitator shaft. This ensures that the freshest and therefore coolest coolant is first led into the area of the agitator ball mill in which the ground material is the warmest. This is in particular the area near the product outlet after the millbase has flowed through the agitator ball mill in the conveying direction from the millbase inlet side. In particular, the coolant flows through the agitator shaft on the surface of the agitator shaft in the opposite direction to the conveying direction of the ground material through the agitator ball mill. With the help of this counterflow cooling, the cooling process can be further optimized.

One embodiment of the agitator shaft provides that it comprises at least two partial sections, in particular a first terminal partial section, on which the agitator shaft is connected to the drive shaft of the agitator. For example, the first end section has a receiving area, in particular a shaft receiving device, in which the free end of the drive shaft can be arranged and connected to the agitator shaft in a rotationally fixed manner. Furthermore, at least one second section is provided. The second section is preferably hollow on the inside. In addition, passage openings are preferably formed in the second partial section between the outer lateral surface and the hollow interior or interior area. In particular, a plurality of passage openings are provided which extend parallel to the longitudinal axis of the agitator shaft. A separating device can preferably be formed within the second section. The ground material / auxiliary grinding medium mixture flowing through the grinding gap is deflected at the open end of the second section and flows via the separating device into the hollow interior of the second section. The separating device, which can be designed, for example, as a separating sieve or classifying rotor, in particular holds back the auxiliary grinding bodies and conveys them back together with possibly not yet sufficiently comminuted regrind through the passage openings into the grinding gap. The ground material, which has been comminuted sufficiently, is conducted through the hollow interior to a product outlet of the agitator ball mill and can be removed there.

The auxiliary grinding bodies are preferably concentrated in this so-called grinding chamber due to the only small grinding gap between the stirring shaft and the inner wall of the grinding container. Only a small part of the auxiliary grinding bodies is deflected together with the regrind and flows through the separating device into the hollow interior of the second section.

According to one embodiment, the second partial section is a central partial section to which another third terminal section follows. This third section also has a hollow interior. In the case of a cylindrical base body of the agitator shaft, the interior spaces of the second and optionally third section are preferably likewise cylindrical and have a circular cross section, the radius of the cross section of the interior in the third section being greater than or equal to the radius of the cross section of the interior is in the second section. In addition, the cylindrical inner cavities each have a longitudinal axis which is congruent to the longitudinal axis of the agitator shaft.

In the third section there are preferably no passage openings between the interior and the outer surface of the agitator shaft. Instead, a wear protection sleeve can be arranged in the interior of the third section, which is preferably also cylindrical. In particular, the wear protection sleeve is arranged between a container bottom of the grinding container and the separating device in the second interior area. In this embodiment, the regrind / grinding aid mixture flowing through the grinding gap is deflected at the open end of the third section within the annular gap formed between the wear protection sleeve and the stirring shaft in the direction of the second section by separating the regrind from the grinding aids, as is the case with it has already been described above.

It is preferably provided that the at least one cooling channel extends within the first terminal section and at least in regions within the second, central section. In one embodiment of a stirrer shaft comprising three sections, it can be provided that the at least one cooling channel extends through all three sections. A meandering cooling channel can, for example, comprise parallel sections which are each formed between passage openings within the second section of the agitator shaft. The parallel sections can extend at least partially into the first and / or third section of the agitator shaft. Corresponding deflection regions are formed in particular at the terminal regions of the first and third sub-sections of the agitator shaft, which deflect the coolant from one parallel section into the next parallel section, so that the coolant flows through parallel sections arranged directly adjacent to one another, in each case preferably in opposite directions .

In particular, it is provided that such a cooling duct comprises an even number of parallel sections, so that the coolant inlet and the coolant outlet are each located at the same end of the agitator shaft. In this case, the coolant flows through, for example, the first, third and fifth parallel section etc. in a first flow direction and the second, fourth and sixth parallel section etc. in an opposite second flow direction. The material to be ground / auxiliary grinding material flows through the grinding gap in a first conveying direction, which corresponds, for example, to the first flow direction, and is redirected within the second and / or third section of the agitator shaft, in particular to a second conveying direction, which corresponds to the second flow direction. The cooling water guide, in particular the cooling water inlet and outlet, can be formed by an insertion part which can be arranged and fastened, for example, together with the drive shaft on the first section of the agitator shaft; For example, the insert part can be placed on the end of the drive shaft and arranged and fastened together with it in the shaft bushing, the cooling water supply and drain line being connected to the at least one cooling channel of the agitator shaft.

A plurality of stirring elements are preferably arranged on the stirring shaft. In particular, a regular arrangement of stirring elements arranged in rows parallel to the longitudinal axis of the stirring shaft and / or in a row in succession along a circumferential line of the base body of the stirring shaft is provided. All stirring elements can be of identical design or can also have different shapes. In addition, areas can be provided on the agitator shaft in which more cams are formed than in other areas, etc.

The stirring elements are preferably designed as cams protruding from the base body of the agitator shaft, the connecting surface of the cams formed on the base body being relatively large, in particular in comparison to the height of the cams with which they project radially beyond the base body.

The cam has a connecting surface formed on the base body of the agitator shaft, an upper side facing the inside of the grinding container, a side leading in the direction of rotation of the agitator shaft, a side trailing in the direction of rotation of the agitator shaft and two sides arranged between the leading side and the trailing side. The leading side is also referred to as the flow side and the trailing side is also referred to as the side facing away from the flow. The distance between the connection surface and the top is called the height of the cams.

Heat can advantageously be dissipated from the material to be ground / grinding aid mixture into the stirrer shaft and in particular into the coolant within the at least one cooling channel of the stirrer shaft via the relatively large connecting surface of the cams. The shape of the cams, described in more detail below, reduces the sensitivity of the ceramic material to breaking off or breaking off. The base body and cams are manufactured together as a monolithic component from a ceramic material, in particular by means of a 3D printing process, so that there is a direct material connection between the base body of the agitator shaft and the cams. The one-piece design of the agitator shaft promotes both stability and heat conduction, as there are no potential breakages and heat conduction barriers.

For a good stability of the cams and to achieve a consistently good grinding result, it is advantageous if each cam has a connection surface to the base body of the agitator shaft and a leading side, a ratio of the projection of the leading side to a plane normal to the base body of the agitator shaft and the size of the connection area is less than 1.

The leading side is referred to below as the face-side inflow surface. Preferably, an angle of inclination of the face-side inflow surface with respect to the plane perpendicular to the base body can be in a range from -45 ° to 85 °. An angle of 0 ° corresponds to an inflow surface arranged at right angles to the base body, whereas an angle with a negative sign denotes an undercut inflow surface, i. H. an inflow surface that is inclined so that they virtually cover a certain area of the connecting surface. Tilt angles with a positive sign therefore characterize a face-side inflow surface that is tilted in reverse, ie. H. in which the end of the inflow surface located on the base body is flowed to first.

Furthermore, it has turned out to be advantageous if each cam has a connecting surface to the agitator shaft with a greatest width and the ratio of the height of each cam to the agitator shaft and the greatest width is greater than 0.2. The connection surface just mentioned corresponds in particular to a base surface of each cam and means the surface with which each cam is in contact with the agitator shaft. It has also proven to be advantageous if each cam has a connecting surface to the agitator shaft with a greatest length and the ratio of the height of each cam and the greatest length is less than 1.

It is also advantageous if each cam has a connecting surface to the agitator shaft with a greatest length and a greatest width, the ratio of the greatest width and the greatest length being less than 1.

If several cams are arranged in succession in the circumferential direction of the main body of the agitator shaft in a row along a circumferential line of the main body of the agitator shaft, then it can be advantageous, for example, to select a distance between the cams of a row which are successive in the circumferential direction, which is equal to or greater than the greatest length of a cam in the circumferential direction. If a plurality of cams are successively arranged in a row along a plurality of circumferentially spaced circumferential lines, then an axial distance between two axially adjacent rows of cams can advantageously be selected to be greater than or equal to 1.1 times the greatest width of a cam. If cams spaced apart from one another in the axial direction are arranged on the base body of the agitator shaft, provision can be made for the cams to be arranged axially in line with one another or offset.

As already described above, a wear protection sleeve can be arranged in the third terminal partial section of the agitator shaft, in particular in the third interior area, and can be installed inside the agitator ball mill in such a way that it can be easily replaced.

The wear protection sleeve is at least partially cylindrical, in particular as a hollow cylinder. The hollow cylinder has an outer diameter that is smaller than the inner diameter of the third interior area. A fastening region, for example a flange, can be provided on an end region of the wear protection sleeve in order to position and fasten the wear protection sleeve in or on the agitator ball mill.

In particular, a grinding gap is again formed between the inner circumferential surface of the agitator shaft in the third interior or interior region and the outer circumferential surface of the preferably cylindrical wear protection sleeve, in which the material to be ground / auxiliary grinding body mixture is guided in the direction of the second interior region of the second partial section. The wear protection sleeve is preferably also made in one piece and in particular made of a ceramic material and can be produced analogously to the stirrer shaft, for example in a 3D printing process.

Furthermore, it can be provided that the wear protection sleeve comprises at least one cooling channel, which, for example, is also meandering is formed and thus forms a large cooling surface. The outer circumferential surface of the wear protection sleeve can also be designed with cam-shaped elevations. The shape of the elevations can correspond, for example, to the shape of the above-described cams arranged on the agitator shaft. The elevations reduce the gap between the inner surface of the agitator shaft in the third interior area and the outer surface of the wear protection sleeve. The elevations serve in particular as wipers in order to prevent ground material and / or auxiliary grinding bodies from adhering to the inner surface of the agitator shaft. Instead, the surveys ensure that the material to be ground / auxiliary grinding body mixture flows in the direction of the passage openings for returning the auxiliary grinding bodies in the direction of the grinding chamber formed between the outer surface of the stirring shaft and the inner wall of the grinding container.

The wear protection sleeve can preferably be used in an agitator ball mill in connection with the above-described agitator shaft. The wear protection sleeve can also be used in connection with a stirrer shaft manufactured according to conventional methods. In this respect, it should be emphasized that the monolithic design of the wear protection sleeve with or without elevations formed on the outer lateral surface and / or with or without at least one cooling channel constitutes an independent invention.

A previously described, monolithic with cams or the like. and at least one cooling channel designed agitator shaft combines the advantages of optimal cooling with maximum wear resistance and is therefore particularly suitable for use in high-performance mills.

The application also includes in particular one-piece stirrer shafts, in particular made of a ceramic material, which are designed without a cooling channel. These agitator shafts also preferably have at least two differently designed partial sections, in particular at least one first terminal partial section for fastening the agitator shaft to a drive shaft and at least one second partial section with a hollow inner area and through openings between the inner area and the outer surface of the Stirrer shaft in the second section.

At this point, it should be expressly mentioned that all aspects and design variants which were explained in connection with the device according to the invention equally relate to or may be partial aspects of the method according to the invention. Therefore, if there are certain aspects and / or relationships and / or effects at a point in the description or also in the definition of claims for the device according to the invention, then this applies equally to the method according to the invention. The reverse applies, so that all aspects and design variants that have been explained in connection with the method according to the invention also relate to or may be partial aspects of the device according to the invention. If, therefore, at one point in the description or also in the definition of claims for the method according to the invention, certain aspects and / or relationships and / or effects are mentioned, this applies equally to the device according to the invention.

Figure list

• 1 zeigt eine perspektivische Darstellung einer Ausführungsform einer erfindungsgemäß einstückig ausgebildeten Rührwelle.
• 2 zeigt eine technische Darstellung einer Seitenansicht der Rührwelle gemäß 1.
• 3 zeigt eine Schnittdarstellung der Rührwelle entlang der Schnittlinie A-A gemäß 2.
• 4 zeigt eine weitere Schnittdarstellung der Rührwelle entlang der Schnittlinie B-B gemäß 3.
• 5 zeigt eine technische Darstellung einer perspektivischen Ansicht der Rührwelle.
• 6 zeigt eine aufgeschnittene Rührwelle mit freigelegten mäanderförmigen Kühlkanälen.
• 7 zeigt eine seitliche Darstellung einer Verschleißschutzhülse.
• 8 zeigt eine perspektivische Darstellung der Verschleißschutzhülse.
• 9 zeigt eine Vorderansicht einer Rührwerkskugelmühle.
• 10 zeigt eine Schnittdarstellung der Rührwerkskugelmühle entlang der Schnittlinie A-A gemäß 9.
• 11 zeigt eine Schnittdarstellung der Rührwerkskugelmühle entlang der Schnittlinie B-B gemäß 10.
• 12 zeigt eine Schnittdarstellung der Rührwerkskugelmühle entlang der Schnittlinie C-C gemäß 11.
• 13 zeigt eine Schnittdarstellung der Rührwerkskugelmühle entlang der Schnittlinie D-D gemäß 12.
• 14 zeigt eine Schnittdarstellung der Rührwerkskugelmühle gemäß den Schnittlinien E-E gemäß 9.
• 15 zeigt eine perspektivische Darstellung einer weiteren Ausführungsform einer erfindungsgemäß einstückig ausgebildeten Rührwelle mit Gegenstromkühlung.
• 16 zeigt einen Längsschnitt einer Rührwerkskugelmühle mit einem als Gegenstromkühlung ausgebildeten Kühlkanal.
• 17 zeigt einen Querschnitt einer Rührwerkskugelmühle mit Rührwelle gemäß 16 entlang einer Schnittlinie A-A.
• 18A bis 18E zeigen jeweils weitere Ausführungsformen von Rührwellen.

In the following, exemplary embodiments are intended to explain the invention and its advantages with reference to the attached figures. The size ratios of the individual elements to one another in the figures do not always correspond to the real size ratios, since some shapes are simplified and other shapes are shown enlarged in relation to other elements for better illustration.

• 1 shows a perspective view of an embodiment of an integrally formed stirrer shaft according to the invention.
• 2nd shows a technical representation of a side view of the agitator shaft according to 1 .
• 3rd shows a sectional view of the agitator shaft along the section line AA according to 2nd .
• 4th shows a further sectional view of the agitator shaft along the section line BB according to 3rd .
• 5 shows a technical representation of a perspective view of the agitator shaft.
• 6 shows a cut agitator shaft with exposed meandering cooling channels.
• 7 shows a side view of a wear protection sleeve.
• 8th shows a perspective view of the wear protection sleeve.
• 9 shows a front view of an agitator ball mill.
• 10th shows a sectional view of the agitator ball mill along the section line AA according to 9 .
• 11 shows a sectional view of the agitator ball mill along the section line BB according to 10th .
• 12th shows a sectional view of the agitator ball mill along the section line CC according to 11 .
• 13 shows a sectional view of the agitator ball mill along the section line DD according to 12th .
• 14 shows a sectional view of the agitator ball mill according to the cutting lines EE according to 9 .
• 15 shows a perspective view of a further embodiment of a stirrer shaft with countercurrent cooling designed in one piece according to the invention.
• 16 shows a longitudinal section of an agitator ball mill with a cooling channel designed as a countercurrent cooling.
• 17th shows a cross section of an agitator ball mill with agitator shaft according to 16 along a cutting line AA .
• 18A to 18E each show further embodiments of agitator shafts.

Identical reference numerals are used for identical or identically acting elements of the invention. Furthermore, for the sake of clarity, only reference numerals are shown in the individual figures which are necessary for the description of the respective figure. The illustrated embodiments merely represent examples of how the device according to the invention or the method according to the invention can be designed and do not constitute a final limitation.

1 to 6 show different views and sectional views of an integrally formed stirrer shaft according to the invention 1 . Such an agitator shaft 1 is preferably in an agitator ball mill 50 used as follows based on the 9 to 14 is explained in more detail. The agitator shaft 1 has a cylindrical body 2nd with a longitudinal axis L on, being on the outer surface of the cylindrical body 2nd Stirring elements 3rd , especially cams 4th , are trained. The outer surfaces of the cams 4th and not by cams 4th covered outer surfaces of the cylindrical body 2nd together form the outer surface 5 the agitator shaft 1 . The stirring elements 3rd are in several rows, especially in an aligned arrangement, on the outside of the cylindrical base body 2nd formed, the rows parallel to the longitudinal axis L the agitator shaft 1 are arranged and / or formed.

According to the invention it is provided that the agitator shaft 1 is formed in one piece and in particular consists of a ceramic material. The agitator shaft is particularly preferred 1 produced from the ceramic material by a single process step. A 3D printing method is particularly preferably used for this purpose, since with this method, cavities within the agitator shaft are also used in a single method step 1 can be generated.

The ceramic material can be, for example, silicon carbide (SiC), in particular sintered silicon carbide (SSiC), silicon carbide with free silicon (SiSiC), silicon nitride, zirconium oxide or mixed ceramics. Silicon carbide ceramics have high wear resistance, low thermal shock sensitivity, low thermal expansion, high thermal conductivity, good resistance to acids and alkalis and are also light and retain their positive properties up to temperatures above 1400 ° C. In addition, silicon carbide is toxicologically safe and can therefore also be used in the food sector. Silicon nitride has a reduced hardness compared to silicon carbide. However, a stalk recrystallization of the β-silicon nitride crystals can be brought about by a sintering process, which leads to an increased fracture toughness of the material. The high fracture toughness in combination with small defect sizes gives silicon nitride one of the highest strengths among the engineering ceramic materials. The combination of high strength, low coefficient of thermal expansion and a relatively low modulus of elasticity make silicon nitride ceramic particularly suitable for components subject to thermal shock. In contrast to other ceramic materials, zirconium oxide has a very high resistance to the spread of cracks. In addition, zirconium oxide ceramic has a very high thermal expansion and is therefore often chosen when realizing connections between ceramic and steel.

In the technical representation of a side view of the agitator shaft 1 according to 2nd and in the cut representation according to 6 is a cooling channel 6 to recognize the inside of the one-piece agitator shaft 1 is trained. It preferably extends at least in regions parallel to the longitudinal axis L the agitator shaft 1 . It is particularly preferably provided that the cooling channel 6 between the end areas of the agitator shaft 1 extends in a meandering manner and in particular is deflected in each case at the end regions, it being possible for the regions between the deflections to be arranged essentially parallel to one another. In 2nd are, for example, three parallel sections 61 , 62 , 63 of the cooling channel 6 recognizable, which are parallel to each other and also parallel to the longitudinal axis L the agitator shaft are arranged. Between the three parallel sections 61 , 62 , 63 are in the end areas of the agitator shaft 1 two deflection areas 67 , 68 educated.

A the first parallel section 61 in a first flow direction SR1 coolant flowing through is in the first deflection area 67 in the second parallel section 62 deflected and flows through it in a second flow direction SR2 that are opposite to the first flow direction SR1 runs. The coolant is then in the second deflection area 68 in the third parallel section 63 deflected and flows through it in turn in the first flow direction SR1 .

In the 3rd Shown sectional view of the agitator shaft 1 along the cutting line AA according to 2nd shows that the inside of the agitator shaft 1 trained cooling channel 6 six parallel sections 61 , 62 , 63 , 64 , 65 and 66 has, each being the first parallel section 61 and the second parallel section 62 over a first deflection area 67 are connected, the second parallel section 62 and the third parallel section 63 over a second deflection area 68 are connected, the third parallel section 63 and the fourth parallel section 64 are connected via a third deflection area (not shown), the fourth parallel section 64 and the fifth parallel section 65 are connected via a fourth deflection area (not shown) and the fifth parallel section 65 and the sixth parallel section 66 over a fifth deflection area 69 (compare 6 ) are connected. In particular, it can be provided that the coolant flows through the first parallel section 61 of the cooling channel 6 into the agitator shaft 1 is initiated and over the sixth parallel section 66 of the cooling channel 6 from the agitator shaft 1 is diverted.

The agitator shaft 1 has three subsections, in particular a first terminal subsection I. , a second middle section II and a third terminal section III . The agitator shaft 1 can at its first terminal section I. with a drive shaft 70 the agitator ball mill (not shown). This is in the first part of the final section I. for example a wave recording 7 educated. The agitator shaft 1 is at least partially designed as a hollow shaft, in particular the second part section II and the third section III and if necessary the first partial section I. each have interior areas. In particular, the second middle section has II a first hollow interior or interior area 12th and the third section III a second hollow interior or interior area 13 on. These preferably also have a cylindrical shape, the longitudinal axis of which is congruent with the longitudinal axis L the agitator shaft 1 is trained. It is also provided that the third section III is open at the end and shows a further enlarged hollow interior, in particular in this open area. As below in connection with the 9 to 14 a wear element or the like can be explained in this hollow interior. to be ordered.

Furthermore, it can be provided that in the second middle section II between the hollow interior area 12th and the outer surface 5 the agitator shaft 1 Openings 15 are trained, whose function also in connection with the 9 to 14 is explained. The second middle section II is therefore also referred to as an open section, while the first section I. and the third section III each represent closed sections. The passage openings 15 extend in particular parallel to the longitudinal axis L the stirrer shaft preferably between the rows of stirring elements 3rd how they are related in particular 1 have been described.

For example, using the 6 the at least one cooling duct extends well 6 preferably through all three sub-sections I. . II and III the agitator shaft 1 , with the deflection areas 67 , 68 , 69 in each case in the final sub-sections I. and III are trained. In particular, the cooling channel 6 meandering - this is shown in more detail below.

4th shows a longitudinal section of the agitator shaft 1 , in particular a sectional view of the agitator shaft 1 along the cutting line BB according to 3rd . At 3rd it is in particular a cross section of the agitator shaft 1 in the second section II , in particular by the stirring elements 3rd goes through. The passage openings are good here 15 between the first hollow interior area 12th and the outer surface 5 the agitator shaft 1 recognizable. In 4th it can be seen that the cooling duct 6 especially parallel to the longitudinal axis L and to the parallel-axially extending passage openings 15 is formed, each with a parallel section 61 , 62 , 63 , 64 , 65 , 66 of the cooling channel 6 adjacent to in a series of stirring elements 3rd extends.

7 shows a side view of a wear protection sleeve 30th and 8th shows a perspective view of the wear protection sleeve 30th . The arrangement of the wear protection sleeve 30th inside an agitator ball mill 50 and their function is particularly in connection with the 10th , 12th and 13 described below.

The wear protection sleeve 30th is at least partially cylindrical, in particular the wear protection sleeve 30th as basic body 32 a hollow cylinder 33 on, on the outside preferably elevations 34 , in particular in the form of cams described in more detail below 35 are trained. The hollow cylinder has an outer diameter d30 that is smaller than the smallest inside diameter dlll of the third interior area III the agitator shaft 1 (compare 2nd ). At one end of the wear protection sleeve 30th can be a fastening area, for example a flange 36 , be provided to the wear protection sleeve 30th in or on the agitator ball mill 50 to position and fasten, especially around the wear protection sleeve 30th at the bottom of the grinding container 59 , especially in a suitable holder on the bottom of the grinding container 59 to determine - compare 10th and 12th .

The wear protection sleeve 30th is preferably also in one piece and in particular made of a ceramic material and can be analogous to the agitator shaft 50 can be produced, for example, in one of the ceramic materials described above using the 3D printing process.

It can also be provided that the wear protection sleeve 30th comprises at least one cooling channel, which is also meandering, for example, and thus forms a large cooling surface (not shown). The formation of the at least one cooling duct of the wear protection sleeve can be the formation of a cooling duct 6 the agitator shaft 1 correspond. The supply lines for the coolant supply and coolant discharge can be routed through the bottom of the grinding 59 , compare 10th , 12th ) be trained.

The wear protection sleeve 30th can preferably in one of the 9 to 14 illustrated agitator ball mill 50 with an agitator shaft 1 according to the 1 to 6 be used. The wear protection sleeve 30th can, however, also be used in connection with an agitator shaft produced by conventional methods.

9 to 14 show different views and representations of an agitator ball mill 50 with an agitator shaft according to the invention 1 , especially shows 9 a front view of an agitator ball mill 50 , 10th shows a sectional view of the agitator ball mill along the section line AA according to 9 and 11 shows a sectional view of the agitator ball mill 50 along the cutting line BB according to 10th .

The agitator ball mill 50 includes one along a horizontal axis L50 extending cylindrical grinding bowl 51 with an inner surface 52 . The grinding bowl 51 can be made of a metal or analogous to the agitator shaft 1 be made of a ceramic material. Furthermore, it can be provided that the grinding container is designed to be coolable and, for example, an outer cylinder 53 and an inner cylinder 54 includes, between which a cold room 55 is formed in the via a suitable coolant inlet 56 and a coolant outlet 57 Coolant K can be initiated. The grinding bowl 51 also includes a grinding container lid 58 and a grinding vessel bottom 59 .

Inside the grinding bowl 1 is an agitator shaft 1 with a longitudinal axis L arranged horizontally. The longitudinal axis L the agitator shaft 1 also represents their axis of rotation and is also congruent with the horizontal axis L50 of the grinding container 51 arranged. The agitator shaft 1 corresponds to that in the 1 to 6 described agitator shaft 1 , so that reference is made to the description of the features thereof.

Through the grinding container lid 58 passing through is a drive shaft 70 arranged with a drive, such as an electric motor or the like. (not shown) is connected. The drive shaft 70 is rotatable with the agitator shaft 1 connected, in particular that reaches into the grinding container 51 protruding end of the drive shaft 70 in the wave recording 7 in the first section I. the agitator shaft 1 . Furthermore, the grinding container cover includes 58 the regrind inlet 71 , over which the regrind M into the agitator ball mill 50 is filled. In the bottom of the grinding container 59 is a product outlet 72 provided by which the ground product P the agitator ball mill 50 leaves.

Between the inner surface 52 of the grinding container 51 and the outer surface 5 the stirrer shaft, especially in the area of the stirrer elements 3rd , is an annular grinding gap MS educated. In the operation of the agitator ball mill 50 it contains the regrind / auxiliary grinding mixture. By rotating the agitator shaft 1 in combination with the grinding aids (not shown) the ground material M in the grinding gap MS claimed so that it is comminuted, for example by impacting regrind particles against one another, by shear forces etc. To reinforce the comminution effect, it can be provided that on the inner lateral surface 52 of the grinding container 51 projections such as cams, rods or the like can also be arranged, which on the one hand bring about additional mixing of the regrind / grinding aid mixture and on the other hand for example the number of those in the grinding gap MS collision processes taking place increases and thus the crushing effect of the agitator ball mill 50 increases.

It is also envisaged that the product outlet 72 within a so-called recording part 75 is formed, which extends through a central opening in the bottom of the grinding container 59 extends. This recording part 75 can also via cooling channels 76 have through which to cool the product P Coolant K is directed. The recording part 75 extends in particular axially in the inner cavity of the agitator shaft 1 towards the grist inlet 71 and is in the area of the product outlet 72 in some areas from the wear protection sleeve 30th surround. At the end area of the receiving part 75 the the product outlet 72 is arranged axially opposite, is preferably a separating sieve described in more detail below 40 arranged that serves to retain the grinding aid inside the agitator ball mill while the product P is removed.

The in 11 shown cross section of the agitator ball mill 50 shows in particular a cross section in the region of the second central section II the agitator shaft 1 , comparable to 3rd . The enlarged detail shows in particular an alternative embodiment of a cooling duct 6 * , which does not have a circular cross section, but is designed with an optimized, enlarged cross section.

In this regard, the shape of the cam should be considered 4th To be received. As already described, the agitator shaft 1 made in one piece, in particular the stirring elements 3rd in the production of the agitator shaft 1 directly trained and not attached later. The stirring elements 3rd are in particular as of the cylindrical body 2nd the agitator shaft 1 protruding cams 4th educated. The one on the main body 2nd the agitator shaft 1 trained connection surface 20th the cam 4th is relatively large, especially in relation to the radial height H the cam 4th . The shape of the cams 4th can assume any geometrical shape, both axially and radially, for example trapezoidal, with rounded corners, with chamfered edges, etc. The connecting surface 20th corresponds in particular to a base area of each cam 4th and means the surface with which each cam 4th in contact with the outer surface of the agitator shaft 1 stands.

Since in the illustrated embodiment, the cooling channel 6 , 6 * adjacent to the cams 4th is formed over the large connection area 20th the cam 4th Advantageously, heat from the material to be ground / grinding aid mixture into the coolant within the cooling channel 6 , 6 * be dissipated because of the large connection area 20th dissipates heat more effectively. Furthermore, the shape of the cams is particularly sensitive to ceramic material 4th significantly reduced compared to breaking off or breaking out. The one-piece design of the agitator shaft 1 promotes both stability and heat conduction, as there are no potential break points and heat conduction barriers.

For good cam stability 4th and to achieve a consistently good grinding result, it is advantageous if each cam 4th a connecting surface 20th to the basic body 2nd the agitator shaft 1 and an inflow face at the front 21 has (compare also 1 ), where a ratio of a projection of the face flow area 21 on a perpendicular to the body 2nd the agitator shaft 1 standing level and the size of the connecting surface 20th is less than 1.

It is advantageous, for example, if each cam 4th a connecting surface 20th to the agitator shaft 1 with a greatest width and the ratio of the height of each cam 4th normal to the agitator shaft 1 and the largest width is greater than 0.2. Furthermore, every cam can 4th a connecting surface 20th to the agitator shaft 1 have a greatest length, the ratio being the height of each cam 4th and the greatest length is preferably less than 1. According to a further embodiment, it is advantageous if each cam 4th a connecting surface 20th to the stirrer shaft 1 with a greatest length and a greatest, the ratio of the greatest width and the greatest length being less than 1.

In this context, the 18A to 18E referred. 18A to 18E each show further embodiments of agitator shafts 1 . These each show a cross section of the outer surface 5 , to the representation of the passage openings, cooling channels etc. analogously to 3rd was waived here. In particular, the arrangement and design of the stirring elements in each of the various embodiments 3rd or cams 4th on the outer surface 5 differently. For example, the inclination is in the direction of rotation D leading side or inflow surface 21 and the inclination in the direction of rotation D lagging side trained differently.

In this case, an angle of inclination of the front face face 21 with respect to a normal to the inside of the grinding bowl 59 standing plane and / or a normal to the cylindrical outer surface of the agitator shaft 1 standing level in a range from level in a range from -45 ° to 85 °. An angle of 0 ° corresponds to an inflow surface 21 that are within a normal to the inside of the grinding bowl 59 standing level (compare 18C ), whereas an angle with a negative sign has an undercut inflow surface 21 referred to, ie an inflow surface 21 that is inclined so that it covers a certain area of the interface 20th quasi covered (compare in particular 18D , 18E) . An angle of inclination with a positive sign therefore characterizes an inflow face at the end 21 , which is inclined in reverse, ie in the case of the base body 2nd located end of the inflow surface 21 first is flowed against (compare in particular 18A , 18B , 18E) .

Basically, it is advantageous to promote a large number of cams to promote the desired interaction with the material to be ground / grinding aid mixture 4th on the agitator shaft 1 to provide. The agitator shaft 1 also have cam-free areas, or can have more cams in some areas 4th and less cams in other areas 4th exhibit. In addition, not all cams have to 4th be of the same design, but can be arranged in different shapes and sizes in different areas.

As especially with the help of 1 can be seen, it can be advantageous in the circumferential direction of the base body 2nd the agitator shaft 1 several cams 4th in a row along a circumferential line of the base body 2nd the agitator shaft 1 to be arranged sequentially. For example, a distance between successive cams in the circumferential direction 4th a row equal to or greater than the greatest length of a cam 4th be formed in the circumferential direction.

Are a variety of cams 4th Arranged consecutively in a row along a plurality of circumferentially spaced circumferential lines, an axial distance between two axially adjacent rows of cams is advantageously greater than or equal to 1.1 times the greatest width of a cam 4th . If cams 4th spaced apart in the axial direction on the base body 2nd the agitator shaft 1 trained, then these cams 4th axially either aligned or also offset from one another.

Based on the sectional view 12th who the agitator ball mill 50 along the cutting line CC according to 11 shows, in particular the path of the regrind / auxiliary grinding mixture G inside the agitator ball mill 50 described. Regrind M is via the regrind inlet 71 into the interior of the grinding container 51 filled. This is already partially filled with grinding aids, for example, the interior of the grinding container is already about 80% filled with grinding aids. Due to the rotation of the agitator shaft 1 become the regrind M and the grinding aids (not shown) to form a grinding stock / grinding aid mixture G mixed that along the agitator shaft 1 between the inner surface 52 of the grinding container 51 and the outer surface 5 the agitator shaft 1 in a first direction of funding FR1 towards the bottom of the grinding container 59 flows. Between the open end area of the third section III the agitator shaft 1 and the grinding vessel bottom 59 a distance is formed in which the flow of the grinding stock / grinding aid mixture G is deflected so that it is now in one of the first conveying directions FR1 opposite second conveying direction FR2 the second hollow interior area 13 of the third section III the agitator shaft 1 flows through.

Within the second interior area 13 is a wear protection sleeve 30th (compare also 10th ) arranged. Such a wear protection sleeve 30th has already been linked to the 7 and 8th described, the description of which reference is hereby made. Between the inner surface of the agitator shaft 50 in the third interior area III and the outer surface of the wear protection sleeve 30th a type of grinding gap is in turn formed in which the material to be ground / auxiliary grinding mixture G in the conveying direction FR2 towards the first hollow interior area 12th of the second middle section II to be led. Between the cams 35 the wear protection sleeve 30th and the inner surface of the agitator shaft 50 in the third interior area III this grinding gap is particularly small. The cams 35 serve in particular as a scraper to prevent ground material and / or auxiliary grinding bodies from adhering to the inner surface of the agitator shaft 1 cling to. Instead, through the cams 35 ensures that the regrind / auxiliary grinding mixture G kept in flow and in the conveying direction FR2 the passage openings 15 is fed in the second section, where a return of the auxiliary grinding bodies in the direction of between the outer surface of the agitator shaft 1 and the inner surface 52 of the grinding container 51 trained grinding room or grinding gap MS .

Inside the first hollow interior area 12th is a separating sieve 40 , a classifying rotor 41 or another suitable device arranged, the grinding aid of the grinding stock / grinding aid mixture G withholds, while sufficiently ground regrind as a finished product P passes through and through the product outlet 72 from the agitator ball mill 50 can be removed. The through the separating sieve 40 , the classifying rotor 41 or similar retained auxiliary grinding body and, if appropriate, not yet sufficiently ground grinding stock M pass through the openings 15 in the second middle section II the agitator shaft 1 back into the grinding gap MS between grinding bowl 51 and agitator shaft 1 and are moving again in the direction of conveyance FR1 emotional.

13 shows a sectional view of the agitator ball mill 50 along the cutting line DD according to 12th , in which the arrangement of the wear protection sleeve 30th within the second hollow interior area 13 of the third section III the agitator shaft 1 can be seen

14 shows a sectional view of the agitator ball mill 50 with a meandering cooling channel 6 according to the cutting lines EE according to 9 . In particular, the course of the first parallel section is here 61 of the cooling channel 6 and the course of the sixth parallel section 66 of the cooling channel 6 visible. The coolant K is through the coolant inlet 56 fed and flows through the first parallel section 61 of the cooling channel 6 in a first flow direction SR1 . As related to 6 the coolant is described 6 deflected several times and finally flows through the sixth parallel section 66 of the cooling channel 6 in a second flow direction SR2 , opposite to the first flow direction SR1 before it goes through the coolant outlet 57 from the agitator shaft 1 is diverted.

15 shows a perspective view of a further embodiment of a stirrer shaft designed in one piece according to the invention 1 . In this embodiment, part of the representation of the stirring elements 3rd , especially cams 4th , as well as the more precise formation of the characteristics of the three sub-sections I. , II and III waived. The related 1 However, the features described also apply to this embodiment, since subsequently in particular the design of the at least one cooling channel 6 to be discussed in more detail.

The cooling channel shown here 6 represents a so-called counterflow cooling. On the one hand, the cooling channel 6 on one itself between the longitudinal axis L and the outer surface 5 the agitator shaft 1 first extending first radial R1 two parallel sections 81 , 82 on. In particular, it is provided that the coolant in the first parallel section 81 is introduced and this in a first flow direction SR1 from the first section I. towards the third section III flows through, the first flow direction SR1 preferably the first conveying direction FR1 for the regrind / auxiliary grinding mixture G according to the 9 to 14 corresponds. In countercurrent cooling, it is provided in particular that the coolant K two parallel sections in succession 81 and 82 , 83 and 84 , 85 and 86 , 87 and 88 . flows through, each on a common radial R , R1 , R2 , R3 , R4 the agitator shaft 1 are located. In particular, the first one is closer to the longitudinal axis L trending parallel section 81 , 83 , 85 , 87 of coolant K flows through. Then the coolant K in the end area of the third section III in a deflection area 95 in each case on the same radial R1 , R2 or R3 arranged parallel section 82 , 84 , 86 or 88 deflected and flows through it in one of the first flow directions SR1 opposite second flow direction SR2 . In the free end area of the first section I. is a redirection area 91 trained of the coolant K from the second parallel section 82 on the first radial R2 in the third, closer to the longitudinal axis L of the agitator shaft formed parallel gate 83 on the second radial R2 redirects. The coolant now flows through the third parallel section 83 again in the first flow direction SR1 and can subsequently over a further deflection area 95 in the third section III in the second radial on the same R2 trained, further from the longitudinal axis L spaced fourth parallel section 84 are deflected, etc. Finally, the coolant flows in the second flow direction SR2 the one on the fourth radial R4 trained last parallel section 88 and becomes from the agitator shaft 1 derived. In the counter-current cooling described here, there are two parallel sections running in parallel 81 and 82 , 83 and 84 etc. of the cooling channel 6 by coolant K in opposite flow directions SR1 , SR2 flowed through on a common radial R the agitator shaft 1 . In particular, the coolant K each close to the longitudinal axis L the agitator shaft 1 from the grist inlet side to the product outlet side. The return of the coolant K from the product outlet side to the regrind inlet side takes place within the agitator shaft 1 in an area adjacent to the outer surface of the agitator shaft 1 .

It can preferably be provided that the coolant K the parallel sections 81 to 88 not flowed through in succession, but that fresh coolant K in each of the closer to the longitudinal axis L trained parallel sections 81 , 83 , 85 , 87 flows in and in each case from the closer to the outer surface of the agitator shaft 1 trained parallel sections 82 , 84 , 86 , 88 is dissipated. The deflection area 91 is here in particular as an annular gap 92 executed. This ensures that the freshest and therefore coolest coolant K is first led into the area of the agitator ball mill in which the ground material is warmest. This is particularly the area near the product outlet after the millbase has flowed through the agitator ball mill from the millbase inlet side. The cooling process can be further optimized with this countercurrent cooling.

16 shows a longitudinal section of an agitator ball mill with a further embodiment of an agitator shaft 1 with a cooling channel designed as countercurrent cooling 6 and 17th shows a cross section of the agitator ball mill with agitator shaft according to 16 along a cutting line AA . It is provided that the coolant in a first flow direction SR1 via a coolant supply line 93 inside the drive shaft 70 the agitator shaft 1 is fed and this through first parallel sections 81 of the cooling channel 6 in the direction of flow SR1 flows through. This first flow direction SR1 preferably corresponds to the first conveying direction FR1 for the regrind / Grinding auxiliary mixture G according to the 9 to 14 . The first parallel sections 81 are also used as inner flow channels 94 designated.

In the end of the third section III is a redirection area 95 formed, each of an inner flow channel 94 with a second parallel section 82 of the cooling channel 6 connects. The second parallel section 82 is also used as an outer flow channel 96 designated. In particular, the coolant K in the deflection area 95 deflected and now flows through an outer flow channel 96 in one of the first flow directions SR1 opposite second flow direction SR2 and then leaves via coolant discharge lines 97 inside the drive shaft 70 the agitator shaft 1 . One inner flow channel each 94 and an outer flow channel 96 are on a radial R of the agitator shaft 1 arranged, the inner flow channel 94 closer to the longitudinal axis L the agitator shaft 1 is arranged as the outer flow channel 96 .

This type of countercurrent cooling also has two parallel sections running in parallel 81 and 82 of the cooling channel 6 on a common radial R the agitator shaft 1 and are from the coolant K in opposite flow directions SR1 , SR2 flows through. It is particularly advantageous here that the coolant K is discharged again after it the agitator shaft 1 once in the first flow direction SR1 and once in the second flow direction SR2 has flowed through. Thus all parallel sections 82 cooled equally strongly, whereas in the exemplary embodiment according to 15 the cooling in the last parallel section 88 compared to the cooling in the second parallel section 82 is significantly reduced. The cooling is therefore an agitator shaft 1 according to 16 compared to the cooling of a first embodiment of the agitator shaft 1 according to 15 further optimized.

In 16 is still the supply of regrind M , the flow guidance of the regrind / auxiliary grinding mixture G inside the agitator ball mill 50 and taking product P shown - also compare the description 12th .

Embodiments are also conceivable in which in the first partial area I. the agitator shaft 1 an annular gap is formed for the coolant supply. Starting from this annular gap, a plurality of cooling channels run in a first flow direction SR1 towards the third section III . A plurality of deflection channels are then formed here, which then coolant flow in counterflow to the first flow direction SR1 and in counterflow to the direction of conveyance FR of the regrind / auxiliary mixture of grinding media G in a second flow direction SR2 lead back again, in particular to a further annular gap, which conducts the “used” cooling medium away. This ensures that each shaft section is cooled with fresh coolant.

The embodiments, examples and variants of the preceding paragraphs, the claims or the following description and the figures, including their different views or respective individual features, can be used independently of one another or in any combination. Features described in connection with an embodiment are applicable to all embodiments unless the features are inconsistent.

Although “schematic” representations and views are generally referred to in the context of the figures, this does not mean in any way that the figure representations and their description should be of secondary importance with regard to the disclosure of the invention. The person skilled in the art is quite capable of extracting enough information from the schematically and abstractly drawn representations that facilitate his understanding of the invention, without having to draw from the drawn and possibly not to scale proportions of the piece goods and / or parts of the device or other drawn elements would be impaired in any way. The figures thus enable the person skilled in the art as a reader to derive a better understanding of the general and / or abstract concept of the invention formulated in the claims and in the general part of the description on the basis of the specifically explained implementations of the method according to the invention and the specifically explained mode of operation of the device according to the invention.

The invention has been described with reference to a preferred embodiment. However, it is conceivable for a person skilled in the art that modifications or changes of the invention can be made without leaving the scope of the following claims.

Reference list

1

Agitator shaft

2nd

cylindrical body

3rd

Stirring element

4th

Cam

5

Outer surface

6.6 *

Cooling channel

7

Wave recording

12th

first interior area

13

second interior area

15

Passage opening

20th

Interface

21

face face

30th

Wear protection sleeve

32

cylindrical body

33

Hollow cylinder

34

Survey

35

Cam

36

flange

40

Separating sieve

41

Classifying rotor

50

Agitator ball mill

51

Grinding bowl

52

Inner surface

53

Outer cylinder

54

Inner cylinder

55

Cold room

56

Coolant inlet

57

Coolant outlet

58

Grinding container lid

59

Grinding container bottom

61

(First) parallel section of the cooling channel

62

(Second) parallel section of the cooling channel

63

(Third) parallel section of the cooling channel

64

(Fourth) parallel section of the cooling channel

65

(fifth) parallel section of the cooling channel

66

(Sixth) parallel section of the cooling channel

67

(First) deflection area of the cooling channel

68

(Second) deflection area of the cooling channel

69

(fifth) deflection area of the cooling channel

70

drive shaft

71

Grist inlet

72

Product outlet

75

Recording part

76

Cooling channel

81

(first) parallel section

82

(second) parallel section

83

(third) parallel section

84

(fourth) parallel section

85

(fifth) parallel section

86

(sixth) parallel section

87

(Seventh) parallel section

88

(eighth / last) parallel section

91

Deflection area

92

Annular gap

93

Coolant supply line

94

inner flow channel

95

Deflection area

96

outer flow channel

97

Coolant discharge line

d30

Outside diameter wear protection sleeve

dlll

Inner diameter of third section

D

Direction of rotation

FR1

first direction of funding

FR2

second funding direction

G

Grist / auxiliary grinding mixture

H

Height of the cams

I.

first terminal section

II

second middle section

III

third terminal section

K

Coolant

L

Longitudinal axis of the agitator shaft

L50

Axis of the grinding bowl of the agitator ball mill

M

Regrind

MS

Grinding gap

P

product

R

Radial

R1

first radial

R2

second radial

R3

third radial

SR1

first flow direction

SR2

second flow direction

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• WO 2000/054884 A [0005]
• DE 2626757 A1 [0005]
• DE 3614721 A1 [0007, 0008]
• WO 2007/042059 A1 [0007]
• DE 3015631 A1 [0008]
• DE 10241924 B3 [0009]

Claims (15)

Agitator shaft (1) for an agitator ball mill (50), the agitator shaft (1) having a longitudinal axis (L) and an outer surface (5) equipped with agitator elements (3), the agitator shaft (1) being formed in one piece with the agitator elements (3) and is made of a ceramic material. Stir shaft (1) after Claim 1 The agitator shaft (1) has at least one cooling channel (6), which preferably extends at least in regions parallel to the longitudinal axis (L) of the agitator shaft (1). Stir shaft (1) after Claim 2 , The at least one cooling channel (6) being meandering. Stir shaft (1) after Claim 2 or 3rd , wherein the at least one cooling channel (6) extends in at least two areas parallel to the longitudinal axis (L) of the agitator shaft (1), a deflection area being formed between the two parallel areas, in particular with one coolant passing the at least two over one Flows through interconnected areas in opposite flow directions. Stir shaft (1) after Claim 4 , wherein two parallel areas, through which coolant flows in opposite flow directions, are arranged on a common radial (R1, R2 or R3) of the agitator shaft (1). Stirrer shaft (1) according to any one of the preceding claims, wherein the stirrer shaft (1) has a first terminal partial section (I) on which the stirrer shaft (1) can be arranged on a drive shaft (70), the stirrer shaft (1) furthermore has a second central section (II) and a third terminal section (III). Stir shaft (1) after Claim 5 , wherein the at least one cooling duct (6) extends within the first terminal section (I) and at least in regions within the second, central section (II), in particular wherein the at least one cooling duct (6) extends through all three parts - Sections extends through. Stir shaft (1) after Claim 6 or 7 , wherein the second, central partial section (II) has a first hollow interior (12), in particular a cylindrical first hollow interior (12) with a longitudinal axis which is congruent with the longitudinal axis (L) of the agitator shaft (1). Stir shaft (1) after Claim 6 or 7 , wherein the third terminal part section (III) has a second hollow interior (13), in particular a cylindrical second hollow interior (13) with a longitudinal axis which is congruent to the longitudinal axis (L) of the agitator shaft (1). Stir shaft (1) after Claim 8 , Through openings (15) being formed between the first hollow interior (12) of the second, middle partial section (II) and the outer lateral surface (5) of the agitator shaft (1) in the region of the second, middle partial section (II). Stirring shaft (1) according to one of the preceding claims, wherein the stirring elements (3) are designed as cams (4) projecting from a base body (2) of the stirring shaft (1), the connecting surface of the cams (4) formed on the base body (2). is relatively large, in particular where each cam (4) has a connecting surface to a main body of the agitator shaft (1) and a leading side, a ratio of the projection of the leading side onto a plane normal to the main body of the agitator shaft and the size of the connecting surface is less than 1. Stirring shaft (1) according to one of the preceding claims, wherein the stirrer shaft (1) with the stirring elements (3) can be produced in a 3D printing process. Agitator ball mill (50) with a grinding container (51) extending along a horizontal or vertical axis (L50) with an inner circumferential surface (52), with a stirring shaft (1) which can be rotated about the horizontal or vertical axis (L50) within the grinding container (51) ) with an outer surface (5), with stirring elements (3) being formed on the outer surface (5), a grinding gap (MS) being formed between the stirring elements (3) of the stirring shaft (1) and the inner surface (52) of the grinding container (51) The agitator shaft (1) is formed in one piece with the agitating elements (3) and consists of a ceramic material, in particular an agitator ball mill (50) with an agitator shaft (1) according to one of the Claims 1 to 12th . Agitator ball mill (50) after Claim 13 comprising a wear protection sleeve (30) which can be arranged in an interior of the agitator shaft (1) and which consists of a ceramic material and is formed in one piece. Method for producing an agitator shaft (1) for an agitator ball mill (50), the agitator shaft (1) being manufactured in one piece from a ceramic material, in particular method for producing an agitator shaft (1) according to one of the Claims 1 to 12th , in particular where the agitator shaft (1) with the Stirring elements (3) is produced by means of 3D printing.

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