AU2020257028B2

AU2020257028B2 - Agitator mill

Info

Publication number: AU2020257028B2
Application number: AU2020257028A
Authority: AU
Inventors: Udo Enderle; Thomas GOLLER
Original assignee: Netzsch Feinmahltechnik GmbH
Current assignee: Netzsch Feinmahltechnik GmbH
Priority date: 2019-10-31
Filing date: 2020-10-19
Publication date: 2021-11-04
Anticipated expiration: 2040-10-19
Also published as: ES2926287T3; EP3815789A1; EP3815789B1; AU2020257028A1; DE102019129467A1; PT3815789T

Abstract

An agitator mill (1) comprising a grinding chamber (7) containing a grinding body and an agitator shaft (3), which revolves therein and which supports a shaft protective sleeve, which revolves with it, and several disk-like agitators (12), which are connected thereto in a rotationally fixed manner and which move the grinding bodies, characterized in that the shaft protective sleeve is divided into several sleeve sections (17), which, at their front end (18), each support a flange (19, 20), wherein each disk-like agitator (12) has a coupling section (14), which is held between the flanges (19, 20) of a preceding and of a following sleeve section (17), wherein the rotationally fixed connection between the flanges (19, 20) and the disk like agitator (12) takes place in that pins (21), the longitudinal pin axis of which is positioned parallel to the axis of rotation of the agitator shaft (3), penetrate through the agitator (12) and the flanges (19, 20). 1/6 lra Cno io

Description

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AGITATOR MILL

The invention relates to an agitator mill , a system for equipping an agitator mill and a method for equipping an agitator mill.

TECHNICAL BACKGROUND

Agitator mills as such are known prior art.

The basic principle of an agitator mill shall initially be described based on Fig. 1.

An agitator mill 1 comprising a horizontal agitator shaft 3 is illustrated schematically in Fig. 1. The complete illustration of the grinding bodies located in the grinding container 2, which are usually designed as glass, steel, or ceramic balls, was forgone. The grinding bodies preferably fill at least 70%, preferably 90%, of the volume of the grinding chamber 7, which is available without internal components.

During operation of the agitator mill 1, the material to be ground is pumped via the inlet 5 of the agitator mill 1 into or through the grinding chamber 7, respectively, which is enclosed by the grinding container 2. In the case of the wet grinding, the material to be ground is solid particles, which are dispersed or suspended, respectively, in a liquid. In many cases, the suspension or dispersion, respectively, is pumped continuously through the grinding chamber. However, it can also be supplied to the agitator mill in batches.

In other cases, an agitator mill of this type can also be used for the dry grinding. It can then be designed, for instance, as agitator mill comprising a vertical shaft, by means of which the grinding material is carried through, for example by a gaseous fluid, mostly in downdraft.

According to its broadest aspect, the present invention relates to both types of the agitator mills. However, its use in agitator mills comprising a horizontal agitator shaft is particularly preferred.

The agitators 8, which are connected in a rotationally fixed manner to the agitator shaft 3 and which are often also identified as grinding disks, are set into rotation by means of a rotational movement of the agitator shaft 3. To create the rotational movement, the agitator shaft 3 can be driven by an electric motor 9, for example, via a belt drive 10. The drive of the agitator mill 1 is thereby mostly located in a housing 11 adjoining the grinding container 2.

The grinding bodies are set in motion by means of the movement of the agitators 8. In response to the movement of the respective grinding body, which in most cases permits the grinding body to completely circle around the agitator shaft repeatedly, is mostly a chaotic movement. As part of the chaotic movement, a grinding body entrained in the circumferential direction by the agitators often has an individual translatory motion, which an autorotation around the center of the respective grinding body is superposed. In many cases, the individual translatory motion also has an at least temporary component in the direction along the longitudinal axis of the agitator shaft, for instance when the agitators are provided with windows, through which the grinding body can move from one chamber into the next. Due to these movements of the grinding bodies, the solid particles contained in the grinding material are comminuted or dispersed, respectively, by means of the impact and shear forces between the grinding bodies. At the discharge of the agitator mill, the separation of grinding material and grinding bodies takes place by means of a suitable separating system. Starting at some micrometers, suspended particles all the way to the range of the average fineness (grain sizes) of < 50 nm can be comminuted.

To ensure that solids, which exceed a certain size, do not leave the grinding chamber 7, a separating system 4, for example in the form of a screen or a filter, is also attached upstream of the outlet 6.

PRIOR ART

An agitator mill, which has an agitator shaft, on which several disk-shaped agitators, which are arranged at an axial distance from one another, are mounted, is known from DE 10219482 Al.

Each individual agitator thereby consists of several disk segments, each of which has an axial aperture and which are screwed to the agitator shaft or to a hub attached to the agitator shaft by means of screw connections. The threaded bores in the shaft or the hubs thereby run in the radial direction. In response to the assembly of the disk segments, the screws are pushed through radial through-counterbores in the disk segments and are screwed to the threads in the hubs or the shaft, respectively, in order to fasten the disk segments. The through-counterbores thereby run from the axial aperture of the disk segments all the way to the surface of the respective disk segment, which abuts against the shaft or the hub in the assembled state.

However, an agitator mill of this type is associated with a significant manufacturing and assembly effort, because each disk segment has to be separately fastened to the agitator shaft.

In the area of the through-counterbore, from which ultimately a significant notching effect emanates, the disks must moreover not fall short of a certain material thickness. To ensure a sufficient safety, this applies in the axial as well as in the radial direction. This may lead to an unintentionally large construction of the agitators.

In view of this, the invention seeks to specify a means, by means of which the manufacturing and assembly effort of an agitator mill as well as the installation space of the agitators, which is especially required in the radial direction, can be reduced.

SUMMARY OF THE INVENTION

According to an embodiment of the invention there is provided an agitator mill comprising a grinding chamber containing a grinding body and an agitator shaft, which revolves therein and which supports a shaft protective sleeve, which revolves with it, and several disk-like agitators, which are connected thereto in a rotationally fixed manner and which move the grinding bodies, wherein the shaft protective sleeve is divided into several sleeve sections, which, at their front end, each support a flange, wherein each disk-like agitator has a coupling section, which is held between the flanges of a preceding and of a following sleeve section, wherein the rotationally fixed connection between the flanges and the disk-like agitator takes place in that pins, the longitudinal pin axis of which is positioned parallel to the axis of rotation of the agitator shaft, penetrate through the agitator and the flanges..

In another embodiment the invention provides a system for equipping an agitator mill according to the invention, which has a grinding chamber and an agitator shaft, which revolves therein and which is to be protected against direct grinding body impact, wherein the system for quipping the agitator mill comprises a multi-part shaft protective sleeve comprising several sleeve sections, which each support a flange on their front end, comprises of pins and agitators, wherein each agitator has a coupling section, which can be installed between the flanges of a preceding and of a following sleeve section, in such a way that the rotationally fixed connection between the flanges and the disk-like agitator takes place in that pins, the longitudinal pin axis of which is positioned parallel to the axis of rotation of the agitator shaft, penetrate through the agitator and the flanges.

In another embodiment the invention provides a method for equipping an agitator mill, which has a grinding chamber containing grinding bodies and an agitator shaft, which revolves therein, comprising agitators, which are set into rotation by the agitator shaft, comprising shaft protective sleeve sections and agitators, wherein the assembly takes place in that a first shaft protective sleeve section is initially pushed onto the agitator shaft until it abuts in a positive manner against an axial stop, wherein the first shaft protective sleeve section is pushed onto the agitator shaft in such a way that, in the assembled state, it is connected in a rotationally fixed manner to the agitator shaft via a strip of said agitator shaft, which acts as feather key, and a first agitator is subsequently pushed onto a section of the first shaft protective sleeve section, which faces away from the axial stop, and is connected in a rotationally fixed manner to the first shaft protective sleeve section via the pins, which are attached to the flange of the first shaft protective sleeve section, which faces away from the axial stop, and any number of further shaft protective sleeve sections and agitators are subsequently assembled to the agitator shaft in the same way as the first shaft protective sleeve section and the first agitator have already been assembled, wherein one shaft protective sleeve section each serves as axial stop for the subsequent shaft protective sleeve section, so that an additional axial stop has to be attached to the agitator shaft on the side, which faces away from the first shaft protective sleeve section, only for the last assembled shaft protective sleeve section.

The agitator mill comprises a grinding chamber containing a grinding body and an agitator shaft revolving therein during operation. The agitator shaft supports a shaft protective sleeve, which revolves with it, and several disks, which are connected in a rotationally fixed manner to the shaft protective sleeve in the broader sense. They form the so called agitators, which will be referred to below as disk like agitators. The agitators set the grinding bodies in motion. The agitator mill according to the invention is characterized in that the shaft protective sleeve is divided into several sleeve sections. At their front end, the sleeve sections each support a flange. The disk-like agitators have a mostly annular disk-shaped coupling section comprising two coupling ring surfaces located opposite one another. This coupling section is located in the center of the agitator. It directly bounds the free central region of the agitator, through which the agitator shaft passes. The coupling section is held between the flanges of a preceding and of a following sleeve section, usually in a sandwich-like manner, viewed in the direction along the axis of the agitator shaft. The holding usually takes place in such a way that one of the coupling ring surfaces in each case abuts against a flange located axially opposite thereto, mostly completely.

A rotationally fixed connection is created between the flanges and the disk-like agitator, in that pins penetrate through the agitator, more exactly the coupling section thereof, and the flanges. With its longitudinal pin axis, the pins are thereby positioned essentially parallel to the axis of rotation of the agitator shaft.

To assemble the shaft protective sleeve and the agitators on the agitator shaft, a first sleeve section of the shaft protective sleeve is initially pushed onto the agitator shaft. A first agitator is subsequently pushed onto the agitator shaft until it abuts with one of its two coupling ring surfaces against the flange of the first sleeve section. A positive connection in the radial direction is thereby simultaneously created between one pin each and one bore each of the agitator provided for this purpose. The pins are thereby ideally fastened to the flange of the first sleeve section, mostly in a non-releasable manner by means of welding. A rotationally fixed connection is thus created between the agitator and the flange of the first sleeve section.

The next sleeve section is subsequently pushed onto the agitator shaft, until its flange abuts against the second coupling ring surface of the agitator. With its bores, which are provided for this purpose, the second flange is thereby also pushed onto the pins, which are fastened to the flange of the first sleeve section. The second sleeve section is thus connected in a rotationally fixed manner to the agitator.

This process can finally be repeated, until the desired number of sleeve sections and agitators have been pushed onto the agitator shaft.

The pins for creating a rotationally fixed connection thereby do not mandatorily have to be fastened to the flange of the respective first sleeve sections of the shaft protective sleeve. It is also conceivable to attach the pins to the flange of the second sleeve section, while the first flange is equipped with the bores, which are complementary to the pins. A further option is to attach or to fix, respectively, the pins to the agitators as pins, which protrude on both sides, and to equip both of the flanges of the sleeve sections adjoining the agitator with corresponding bores, which better reflects the idea of same parts. A further option, which, however, is mostly too complex for the assembly, is to equip both flanges and the agitator located therebetween with bores, and to guide the pins through the bores only following the assembly of the shaft sleeves and of the agitators.

Ideally, the sleeve sections located between the first and the last sleeve section have one flange each on both axial ends. To create a rotationally fixed connection with an agitator and with a consecutive sleeve section, the pins are thereby ideally fastened to a flange, while it is ideal to equip the other flange with bores, into which the pins of the previous sleeve sections, which are pushed through the agitator, can be inserted. Ideally, the flanges are fastened to the sleeves by means of welding.

A connection of this type provides the respective agitator with a particularly firm hold on the agitator shaft. The torque transmitted to it by the agitator shaft and the forces associated therewith stress the pins only slightly. This is so because they find support on both ends in the consecutive flanges. This is why they are not subject to the high stress, to which only a cantilevered beam, which is clamped on one side, is subject. High torques can be transmitted, because each agitator interacts with the feather key of the agitator shaft on both sides (by the shortest route) via the two flanges, which hold it "sandwich configuration".

It generally applies in the context of the invention that pins have significant advantages. With their help, the flanges can be positioned perfectly relative to one another and, together with their sleeve sections, can be connected in a positive manner to form a quasi "monolithic" block. The pinning is better and simpler than the use of through-bolts. This also applies in particular in the case of large agitator mills, in the case of which noticeable tolerances can then occur after all between the feather key, which is then very large, and the feather key groove in the respective flange.

Compared to the use of through-bolts comprising nuts, which protrude into the grinding chamber and then form obstacles there, which possibly wear under constant the "bombardment" of the grinding bodies, the pin solution according to the invention has the advantage that it is absolutely flush with the adjacent areas. In addition, the complex manufacture of a large number of threaded bores in the flanges and/or the agitators can be forgone where no nuts are to be used.

If, in contrast, the sleeve sections located between the first and the last sleeve section have a flange only on one side, two sleeve sections have to in each case be pushed onto the agitator shaft between two agitators, whereby the flanges of the corresponding sleeve sections then have to face away from one another, which should be noted for the sake of patent law-related completeness.

In the case of a construction of this type, the individual parts of the shaft protective sleeve as well as the individual agitators can be assembled easily or quickly, respectively, on the agitator shaft. For this purpose, they only have to be pushed onto the agitator shaft in sequence. The assembly thereby takes place essentially without tools.

A further advantage of an agitator mill designed according to the invention is that the radial ends of the flanges move closer to the center of the shaft. The flanges, which until now had to be designed more voluminously than the pure agitators, thus build smaller. The part of the grinding chamber with no internal components thus becomes larger. This ultimately leads to an enlargement of the usable grinding chamber.

Due to the fact that the agitators are not connected here to the flanges by means of a radial screw-connection, this can furthermore also lead to the further advantage here that the necessary radial and axial wall thickness of the agitators may also sink. This also leads to the productivity-improving enlargement of the volume with no internal components of the grinding chamber.

In this context, the term "without tools" describes that the individual parts are designed in such a way that no hand tools are generally required for the assembly. It is not ruled out, however, that a hammer is used for more easily inserting, for example the pins, into the boreholes. The use of a crane in the case of correspondingly large or heavy components, respectively, is also not ruled out. Moreover, it is conceivable that tools are required prior to and after the assembly of the shaft protective sleeve and agitators on the agitator shaft, in order to prepare the agitator shaft for the assembly, for instance to assemble axial stops on the agitator shaft in order to secure the position of the first and last sleeve section.

The term "grinding body" thereby identifies the bodies, which are located in the grinding chamber of the agitator mill and which cause a comminution of the material to be ground, which is supplied to the agitator mill during operation. These are usually steel, glass, or ceramic balls.

The term "disk-like agitators" describes that the geometry of the agitators is or essentially is cylinders, the diameter of which exceeds the maximum thickness in the direction of its longitudinal axis at least by the factor 1.5, preferably by at least the factor 3. The thickness of the agitators (measured in the axial direction) thereby does not have to run evenly over the entire diameter. Moreover, it is conceivable that the agitators can have further window-like apertures, which run in the axial direction, in addition to the aperture, by means of which they are pushed onto the agitator shaft or the shaft protective sleeve, respectively.

PREFERRED DESIGN OPTIONS

There is a number of options to design the invention in such a way that its effectiveness and usability is improved even further.

It is thus particularly preferred to secure the pins only at one of the two flanges in the direction of their longitudinal pin axis. This preferably takes place in that the pins are welded to the corresponding flange. The pin openings at the other one of the two flanges, in contrast, are designed in such a way that a fit results, which can be added by hand, by inserting the pins into these pin receiving openings. This is preferably a transition fit according to ISO 286.

The agitators thus only have to be pushed onto the agitator shaft or onto a sleeve section of the shaft protective sleeve, respectively, until they abut with their coupling ring surface on the flange of the sleeve section. As soon as the consecutive sleeve section has also been pushed on and abuts with its flange on the agitator, a rotationally fixed connection was established between the agitator and the sleeve sections.

If the two sleeve sections, which surround the agitator, are secured in the axial direction, the agitator is likewise axially secured. Due to the fact that the pins were already secured to the flange of the first sleeve section, and the fit between the pins and the bores, which are provided for this purpose in the flange of the second sleeve section, are transition fits, an assembly of the agitators and sleeve sections without tools on the agitator shaft is ensured.

Due to the fact that no welding or adhesive work has to be performed during the assembly of the agitators and of the shaft protective sleeve on the agitator shaft, and due to the fact that screw connections also do not have to be assembled, which require a certain tightening torque, the risk of a faulty assembly is very small.

In a further preferred embodiment, each agitator is centered on at least one of the flanges, which holds it, by means of an annular ledge formed on it. The centering thereby preferably takes place by means of positive cooperation between the outer jacket surface of a flange of a sleeve section and said annular ledge.

Ideally, the agitator shaft 3 has at least one, preferably at least two entraining strips. The entraining strips are in each case preferably designed as or in the manner of a feather key, to which reference will be made below in a representative manner.

For the most part, they each pass from the first to the last sleeve section. The sleeve sections are entrained by means of positive interaction of the feather keys with the corresponding keyways of both of their flanges in the direction of rotation.

Due to the positive connection between the at least one feather key and the sleeve sections of the shaft protective sleeve, a rotational movement of the shaft is transferred to the shaft protective sleeve.

The at least one feather key can thereby be both in one piece and can comprise of several pieces. If it comprises of several pieces, an axial distance between the individual sections is also conceivable. However, the feather keys are thereby preferably always attached to the agitator shaft in such a way that the sleeve sections can be pushed into their end position in one go without new alignment along the agitator shaft. In the case of a multi-piece embodiment, the individual sections of the feather key thus have to be aligned.

Ideally, the at least one feather key is installed into the agitator shaft without play. The strip is preferably assembled to the agitator shaft, in that it is pressed or screwed to the agitator shaft.

Each agitator is preferably an annular disk, which is closed in the circumferential direction, and not only a piece of cake-like disk sector, which tends to promote the (problem free) transfer of higher torques to the respective agitator. Ideally, this is a disk, which is cast in one piece.

Window-like apertures, which run in the longitudinal axial direction of the disk, are thereby not ruled out. Only the area between the flanges has to be closed in the circumferential direction.

The advantage of such an embodiment of the agitators is that the assembly effort decreases significantly. Several disk sectors do not need to be grouped around a flange or a flange pair and have to be individually fastened thereto any longer. Instead, each agitator as a whole can be pushed onto a flange, whereby the flange, which first receives the agitator, is preferably already equipped with the required pins. As soon as the second flange has been positioned, the agitator has a firm hold solely by pushing the mentioned components together, without first requiring a screw connection in the flange region.

The manufacture of the agitators by means of a casting method is expedient, in particular when window-like apertures are to be provided in the agitators and when they are large components, because no waste is produced in response to the casting method. Material can therefore be saved.

In a further preferred embodiment, each agitator has a coupling ledge, which connects to its inner radius and which is pierced on at least one and preferably both sides from the front sides.

According to the invention, the coupling ledge is thus a section of the agitator, which, measured in the direction along the axis of rotation of the agitator shaft, is thinner than the section of the agitator, which is not pierced. The surfaces of the coupling ledges, which, in the assembled state of the agitator, face the flanges of the sleeve sections, are the already mentioned coupling ring surfaces of the respective agitator.

Ideally, the coupling ledge of each agitator is received completely between the flanges of two directly adjacent sleeve sections.

In a further preferred embodiment, the axial positioning of the sleeve sections and of their flanges is ensured in that the first sleeve section of the shaft protective sleeve, which is pushed onto the agitator shaft, abuts in a positive manner against a first axial stop. Moreover, the last sleeve section, which is pushed onto the agitator shaft, abuts in a positive manner against a second axial stop. The second axial stop thereby acts in reverse axial direction as the first axial stop. Each further sleeve section located between the first and the last sleeve section is preferably not secured directly to the agitator shaft in the axial direction. On the contrary, the axial securing of the sleeve sections located in-between ideally takes place indirectly with the help of sleeve sections, which are adjacent on both sides for the sake of simplicity.

The first sleeve section of the shaft protective sleeve is thus pushed over the agitator shaft until it abuts against a first axial stop. The axial slipping of the sleeve section is thus only still possible in one direction. The further sleeve sections and the agitators are subsequently pushed consecutively onto the agitator shaft. After the last sleeve section is in the desired position on the agitator shaft, a further axial stop is finally attached to the agitator shaft. In the assembled state, said axial stop prevents the slipping of the sleeve section, which was last pushed onto the agitator shaft, in the direction, from which it was pushed onto the agitator shaft. Due to the fact that all of the individual sleeve sections and agitators axially adjoin one another, all sleeve sections and agitators are thus prevented from axially slipping along the agitator shaft.

If one of the axial stops or even both axial stops is not embodied as shaft ledge, it may be necessary to use a tool for the assembly of the axial stop.

In a further preferred embodiment, the sleeve sections, their flanges, and preferably also the exposed surfaces of the agitators are provided with a coating. The coating usually has a friction-increasing effect and/or impulse attenuating effect. For the most part, it also has an effect, which dampens the impact shocks of the falling grinding bodies. Ideally, this is a coating made of rubber or an elastomer, ideally a soft elastomer.

The coated surfaces of the shaft protective sleeve are preferably those, which come into contact with the grinding bodies during operation of the agitator mill. Due to the fact that the friction of the coated surfaces is ideally increased by means of the coating, the grinding bodies, which are in contact with the corresponding surfaces, are set in motion more effectively. The grinding process is thus optimized.

The term "free surfaces" preferably describes those surfaces, which can be accessed directly by the grinding bodies from the grinding chamber side.

The invention also provides a system for equipping an agitator mill with a shaft protective sleeve and agitators, which can be assembled with little effort and which protects the agitator shaft against a contact with the grinding bodies.

An agitator mill of this type has a grinding chamber and an agitator shaft, which revolves therein during operation and which is to be protected against direct grinding body impact.

The system according to the invention for equipping the agitator mill thereby comprises of a multi-part shaft protective sleeve comprising several sleeve sections, which each support a flange on their front end, as well as pins and agitators. A system of this type is characterized in that each agitator has a coupling ring surface, which can be installed between the flanges of a preceding and of a following sleeve section. The rotationally fixed connection between the flanges and the disk-like agitator thereby takes place in such a way that pins penetrate the agitator and the flanges. With their longitudinal pin axis, the pins are thereby positioned completely or at least essentially parallel to the axis of rotation of the agitator shaft.

With the system, a simplified reconditioning of agitator mills of this type is achieved, in the case of which the shaft protective sleeve and the agitators fastened thereto have to be replaced due to wear. The system then realizes the same advantages as have already been mentioned above for the agitator mill as a whole according to the invention.

PREFERRED EMBODIMENT OPTIONS

In a particularly preferred embodiment, the surfaces of the system for equipping an agitator mill, which come into contact with the grinding bodies in the assembled state, are provided with a coating. Ideally, the coating thereby has a friction-increasing and/or attenuating effect, respectively. It corresponds to what was described above.

The invention also provides a method for the simplified equipping or reconditioning of an agitator mill with a shaft protective sleeve and agitators.

The method for equipping an agitator mill comprises a grinding chamber containing a grinding body and an agitator shaft revolving therein comprising agitators, which are set into rotation by the agitator shaft. The method is characterized in that the assembly takes place in that a first sleeve section of the shaft protective sleeve is initially pushed onto the agitator shaft until it abuts in a positive manner against an axial stop. The first sleeve section is thereby pushed onto the agitator shaft in such a way that, in the assembled state, it is connected in a rotationally fixed manner to the agitator shaft via a strip of said agitator shaft, which acts as feather key. A first agitator is subsequently pushed onto a section or flange, respectively, of the first sleeve section, which faces away from the axial stop. The first agitator is connected in a rotationally fixed manner to the first sleeve section via pins, which are attached to the flange of the first sleeve section, which faces away from the axial stop. Any number of further sleeve sections and agitators can subsequently be assembled to the agitator shaft in the same way as the first agitator and sleeve section have already been assembled. One sleeve section each thereby serves as axial stop for the subsequent sleeve section. An additional axial stop has to be attached to the agitator shaft on the side, which faces away from the first sleeve section, only for the last assembled sleeve section.

FIGURE LIST

Embodiments of the present invention will now be described, by way of non-limiting example only, with reference to the accompanying drawings briefly described as follows.

Fig. 1 shows a schematic illustration of an agitator mill;

Fig. 2 shows a sleeve section in the front view, flange without pins in the front view;

Fig. 3 shows a flange of a sleeve section of the shaft protective sleeve with pins in the longitudinal section;

Fig. 4 shows a sleeve section of the shaft protective sleeve with both flanges in the longitudinal section;

Fig. 5 shows an agitator in the front view; and

Fig. 6 shows an agitator in the longitudinal section.

EXEMPLARY EMBODIMENT

The mode of operation of the device according to the invention will be described in an exemplary manner on the basis of Figures 2 to 6.

The front side of a sleeve section 17, which is formed by the flange 20 thereof, is shown in Fig. 2. The flange 20 is formed here as "hole flange" for the insertion of pins.

A sleeve section 17 of this type is pushed onto an agitator shaft, until the flange 20 abuts against an agitator 12, which is likewise assembled on the shaft. The two keyways 23 of the flange 20 thereby establish a positive connection with the entraining strip of the agitator shaft, so that a rotational movement of the agitator shaft is transferred to the sleeve section 17. Compared to the central agitator shaft, the centering of the superstructures thereby usually takes place via flanges 19, 20, which abut with the inner circumferential surface of their central opening against the circumferential jacket surface of the agitator shaft, which is not illustrated here, so as to provide the position.

The flange 20 of the sleeve section 17 has several pin receiving openings 22. When the flange 20 abuts against an agitator 12 in the assembled state, the pins 21 of the flange of a preceding shaft sleeve section protrude into the pin receiving openings 22.

A flange 19, which is located opposite the flange 20 in the assembled state, is illustrated in the sectional view in Fig. 3. The flange 19 is embodied as "pin flange" here, it supports pins 21, which are preferably fixed thereto from the beginning. The flange 19 thereby likewise abuts against the agitator 12, which is not illustrated in Fig. 3. Moreover, the flange 19 likewise has two keyways 23, which form a positive connection with the entraining strip of the agitator shaft.

A rotationally fixed connection between the agitator 12 and the flange 19 is established with the help of the pins 21 of the flange 19. To center the agitator 12 with respect to the flange 19, a jacket surface 25 is provided at the flange 19.

A sleeve section 17 is illustrated in longitudinal section in Fig. 4. The sleeve section 17 comprises of a sleeve 29, as well as the two flanges 19 and 20, which are fastened to the front ends 18 of the sleeve 29, for example by means of the welding seams 26. The sleeve section 17 is equipped with a coating or rubber coating 24, respectively. In most cases, the coating at the sleeve section 17 primarily has the function of attenuating impact shocks of grinding bodies, which hit when falling down. Here, a secondary function of the coating can also be to improve the friction between the grinding bodies in the grinding chamber and the sleeve section, so as to thus improve the entrainment of the grinding bodies. As can be seen, it is preferably the case that the sleeve 29 of the sleeve section 17 does not abut directly against the agitator shaft protected by it, but forms an annular gap with respect thereto. In this way, the sleeve section of the shaft protective sleeve is prevented by all means from transferring forces or impact shocks of falling grinding bodies acting thereon directly to the agitator shaft. The clearance of the sleeve section with respect to the agitator shaft is also maintained after long use, so that the sleeve section can always be replaced without any problems (without clamping) as part of a revision of the mill.

An agitator 12 is illustrated in Fig. 5. It has several window-like apertures 28 here. These apertures can serve the purpose of providing the grinding material flow with a better throughflow from one grinding chamber between two agitators to the next grinding chamber. They might also increase the entraining of the grinding bodies.

It can be seen well here, how the coupling section, which encompasses or bounds, respectively, the central opening of the agitator, forms a coupling ring surface 13 facing the observer, and an annular ledge 14 on the radially outer end thereof. With the coupling ring surface 13, the agitator 12 abuts axially against at least one of the flanges 19 or 20 in the completely assembled state. The centering ideally takes place via the inner circumferential surface 14 of the coupling section 13 (see Fig. 6), which then sits on the exterior jacket surface 25 of a flange 19 or 20, respectively (see Fig. 4). Several pin receiving openings 15 are provided in the coupling section. The pins 21 of the "pin flange" 19 are pushed into said pin receiving openings (in the case of preferred use of such a pin flange), in order to connect the agitator 12 in a rotationally fixed manner to the shaft sleeve.

As can in particular be seen on the basis of Fig. 6, the agitator comprises of an inner metal frame 27 here, which is surrounded by a rubber coating 16. This coating 16 also serves to increase the friction between the agitator 12 and the grinding bodies located in the grinding chamber, here mostly only secondarily, possibly also for attenuating impact shocks. The coating is ideally embodied in such a way that it can be stripped and replaced in the case of wear, which optionally leads to a corresponding use of the agitator 12.

The agitator 12 is illustrated in the sectional view in Fig. 6. The inner metal frame 27 as well as the coating 16 surrounding the metal frame 27 can thus be seen well here.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavor to which this specification relates.

While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the present invention should not be limited by any of the above described exemplary embodiments.

LIST OF REFERENCE NUMERALS

1 schematically illustrated agitator mill 2 grinding container of the schematic agitator mill 3 agitator shaft of the schematic agitator mill 4 separating system upstream of outlet of the schematic agitator mill 5 inlet of the schematic agitator mill 6 outlet of the schematic agitator mill 7 grinding chamber of the schematic agitator mill 8 agitator of the schematic agitator mill 9 motor of the schematic agitator mill 10 belt drive of the schematic agitator mill 11 housing of the drive of the schematic agitator mill 12 agitator 13 coupling ring surface 14 centering inner circumferential surface of the coupling section 15 pin receiving openings in the agitator 16 coating of the agitator 17 sleeve section (part of the shaft protective sleeve) 18 front end of the sleeve 19 flange with pins 20 flange without pins 21 pins 22 pin receiving openings 23 keyway 24 coating 25 jacket surface, at which agitator is centered 26 welding seam 27 inner metal frame of the agitator 28 window-like apertures in agitators 29 sleeve

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. An agitator mill comprising a grinding chamber containing a grinding body and an agitator shaft, which revolves therein and which supports a shaft protective sleeve, which revolves with it, and several disk-like agitators, which are connected thereto in a rotationally fixed manner and which move the grinding bodies, wherein the shaft protective sleeve is divided into several sleeve sections, which, at their front end, each support a flange, wherein each disk-like agitator has a coupling section, which is held between the flanges of a preceding and of a following sleeve section, wherein the rotationally fixed connection between the flanges and the disk-like agitator takes place in that pins, the longitudinal pin axis of which is positioned parallel to the axis of rotation of the agitator shaft, penetrate through the agitator and the flanges.

2. The agitator mill according to claim 1, wherein the pins are secured only at one of the two flanges in the direction of their longitudinal pin axis, while the pin receiving openings at the other one of the two flanges are designed in such a way that a fit results, which can be added by hand, by inserting the pins into these pin receiving openings.

3. The agitator mill according to one of the preceding claims, wherein the agitators are centered on at least one of the flanges by means of an annular ledge.

4. The agitator mill according to one of the preceding claims, wherein the agitators are centered on the flanges by means of the pins.

5. The agitator mill according to one of the preceding claims, wherein the agitator shaft has at least one entraining strip which each pass from the first to the last shaft protective sleeve section, and the shaft protective sleeve sections are entrained by means of positive interaction with the corresponding keyway in the direction of rotation.

6. The agitator mill according to one of the preceding claims, wherein each agitator is a closed, annular disk in the circumferential direction.

7. The agitator mill according to one of the preceding claims, wherein each agitator has a coupling section, which connects to its inner radius and which is pierced from at least one front side.

8. The agitator mill according to the immediately preceding claim, wherein the coupling section is received completely between the flanges of two directly adjacent shaft protective sleeve sections.

9. The agitator mill according to one of the preceding claims, wherein the axial positioning of the shaft protective sleeve sections or of their flanges, respectively, is ensured in that the first shaft protective sleeve section, which is pushed onto the agitator shaft abuts in a positive manner against a first axial stop and that the last shaft protective sleeve section, which is pushed onto the agitator shaft, abuts in a positive manner against a second axial stop, which acts in reverse axial direction, while each of the shaft protective sleeve sections located therebetween is not secured directly to the agitator shaft, but is axially secured only indirectly with the help of shaft protective sleeve sections, which are adjacent on both sides.

10. The agitator mill according to one of the preceding claims, wherein the shaft protective sleeve sections and their flanges are provided with a coating.

11. A system for equipping an agitator mill according to one of the preceding claims, which has a grinding chamber and an agitator shaft, which revolves therein and which is to be protected against direct grinding body impact, wherein the system for quipping the agitator mill comprises a multi-part shaft protective sleeve comprising several sleeve sections, which each support a flange on their front end, comprises of pins and agitators, wherein each agitator has a coupling section, which can be installed between the flanges of a preceding and of a following sleeve section, in such a way that the rotationally fixed connection between the flanges and the disk-like agitator takes place in that pins, the longitudinal pin axis of which is positioned parallel to the axis of rotation of the agitator shaft, penetrate through the agitator and the flanges.

12. A system for equipping an agitator mill according to claim 11, wherein the surfaces of the system for equipping an agitator mill, which come into contact with the grinding bodies in the assembled state, are provided with a coating, .

13. A method for equipping an agitator mill, which has a grinding chamber containing grinding bodies and an agitator shaft, which revolves therein, comprising agitators, which are set into rotation by the agitator shaft, comprising shaft protective sleeve sections and agitators, wherein the assembly takes place in that a first shaft protective sleeve section is initially pushed onto the agitator shaft until it abuts in a positive manner against an axial stop, wherein the first shaft protective sleeve section is pushed onto the agitator shaft in such a way that, in the assembled state, it is connected in a rotationally fixed manner to the agitator shaft via a strip of said agitator shaft, which acts as feather key, and a first agitator is subsequently pushed onto a section of the first shaft protective sleeve section, which faces away from the axial stop, and is connected in a rotationally fixed manner to the first shaft protective sleeve section via the pins, which are attached to the flange of the first shaft protective sleeve section, which faces away from the axial stop, and any number of further shaft protective sleeve sections and agitators are subsequently assembled to the agitator shaft in the same way as the first shaft protective sleeve section and the first agitator have already been assembled, wherein one shaft protective sleeve section each serves as axial stop for the subsequent shaft protective sleeve section, so that an additional axial stop has to be attached to the agitator shaft on the side, which faces away from the first shaft protective sleeve section, only for the last assembled shaft protective sleeve section.