AU2014331412B2

AU2014331412B2 - Roller mill for the comminution of brittle material

Info

Publication number: AU2014331412B2
Application number: AU2014331412A
Authority: AU
Inventors: Egbert Burchardt; Silvio Lorenz; Thomas Mackert; Heinz Schroder
Original assignee: FLSmidth AS
Current assignee: FLSmidth AS
Priority date: 2013-10-01
Filing date: 2014-10-01
Publication date: 2018-01-25
Anticipated expiration: 2034-10-01
Also published as: CL2016000715A1; ZA201601901B; DE102013110893A1; PE20160413A1; AU2014331412A1; WO2015049050A1; DE102013110893B4

Abstract

The roller mill according to the invention for the comminution of brittle material provides two contrarotationally driven milling rollers (1, 2) which in each case have a basic body (3) with a circumferential surface (4) and two end faces (5, 6), wherein the circumferential surface (4) is provided with a surface armour (7) suitable for forming an autogenous wear protection layer, and in each case a closed wear protection ring formed from edge protection elements (8) is provided in the transition region between the circumferential surface (4) and the end faces (5, 6), wherein the edge protection elements (8) comprise pin-shaped profiled bodies (9) by means of which they are held in radial bores (10) of the basic body (3). On the side remote from the bores (10), the pin-shaped profiled bodies (9) of the edge protection elements (8) additionally project from the edge protection elements (8) and interact there with the surface armour (7) to form an autogenous wear protection layer.

Description

The invention relates to a roller mill for the comminution of brittle material.

Roller mills of this type are used, for example, in the cement and minerals industry for the comminution of limestone, dolomite or ore material. The roller surfaces are subjected to enormous wear, so that the milling rolls have to be reconditioned at regular intervals. In order to increase the service times of the roller mills, various wear protection concepts have been developed. In DE 10 2007 032 261 Al the outer shell is formed by a multiplicity of segments which are slid into longitudinal grooves in the basic body. However, this construction leads to churning movements of the segments on the basic body, which has led to premature failure.

EP 0 659 108 Bl proposes a wear protection layer applied to the entire area of the basic body, which has flat zones made of a highly wear resistant material, wherein the interspaces between the highly wear resistant zones are filled with a material with a different wear resistance. However, this solution has the disadvantage that the wear protection is relatively complicated and, in addition, repair requires high outlay, since the entire layer usually has to be renewed. In recent times, however, a wear protection technique has been tried and tested in which a multiplicity of pin-shaped profded bodies project out of the circumferential surface of a basic body, and the distance between the profded bodies is chosen such that, during operation, an autogenous wear protection layer formed of compressed material forms between the profded bodies. Such a surface armor is described, for example, in EP 0 830 897 Bl. This wear protection concept has the advantage that individual worn profiled bodies can also be replaced and also takes into account the abrasive wear which results from a relative movement between material to be milled and milling roll.

By means of the above-described measures, the wear on the roller surface could be reduced to an acceptable extent. However, the previously known measures do not

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2014331412 20 Dec 2017 constitute adequate protection for the roller edges or cannot be produced or cannot be produced economically for large rollers. In EP 1 502 650 BI it has therefore been proposed to provide the roller bodies in the area of each of the roller ends with a circumferential recess, which is designed to be open towards the top and toward a side surface of the milling roll, and in which wear protection elements made of hard metal are arranged in the circumferential direction. In this way, the wear protection elements form a closed ring, which offers high protection against wear.

A similar concept is proposed in DE 103 54 679 Al, where, likewise, hard bodies are arranged on the roller front edge in a circumferential annular shoulder of the roller shell. There, the hard bodies are clamped in the circumferential annular shoulder of the roller shell by means of screw and clamping elements.

It would be advantageous if the present invention would improve the edge protection of the roller mill further.

The roller mill according to the invention for the comminution of brittle material provides two contrarotationally driven milling rollers, which in each case have a basic body with a circumferential surface and two end faces, wherein the circumferential surface is provided with a surface armor suitable for forming an autogenous wear protection layer, and in each case a closed wear protection ring formed from edge protection elements is provided in the transition region between the circumferential surface and the end faces, wherein the edge protection elements comprise pin-shaped profiled bodies, by means of which they are held in radial bores of the basic body. On the side remote from the bores, the pin-shaped profiled bodies of the edge protection elements additionally project from the edge protection elements and interact there with the surface armor to form an autogenous wear protection layer.

The pin-shaped profiled bodies are used firstly for the simple and secure fixing of the edge protection elements and secondly contribute to forming the autogenous wear protection layer, by which means in particular the particularly highly loaded edge regions of the milling rollers are additionally protected.

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For the additional securing of the edge protection elements 8, these, including the pin-shaped profded bodies 9, are provided with an adhesive during the fixing to the circumferential recess 11, wherein it is possible here for this to be a one-component or multi-component adhesive.

In order to fix the edge protection elements, in each case a circumferential recess open radially toward the circumferential surface and axially toward the respective end face of the basic body can be provided in the transition region between the circumferential surface and the end faces. The edge protection elements expediently have a contact surface which is configured so as to be complementary to the area of the basic body in contact therewith. The pin-shaped profiled bodies are preferably designed to be cylindrical and/or conical. Furthermore, in terms of their shape and size, they can be formed to be the same or partially different.

According to a further refinement of the invention, the edge protection elements project axially beyond the end face and/or radially beyond the circumferential surface. Furthermore, the edge protection elements can be provided with an additional wear protection element on the surface pointing toward the end. Here, provision can primarily also be made for the additional wear protection elements to project radially beyond the edge protection elements and to form a collar to limit the autogenous wear protection layer. For the better protection of the end face of the basic body, the additional wear protection elements can be adjoined radially inwardly by wear protection segments or strips, which are fixed to the additional wear protection elements or to the basic body. Here, provision can also be made for the additional wear protection elements to project further beyond the basic body in the axial direction than the further wear protection segments or strips, and for the outer boundary surface of the additional wear protection elements to be chamfered as far as the further wear protection elements or strips.

For the purpose of fixing the edge protection elements, these can each be assigned a pin-shaped profiled body for fixing. However, it is also conceivable for the pinshaped profiled bodies each to be arranged, additionally or exclusively, in the

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2014331412 20 Dec 2017 transition region between two edge protection elements, so that they are each in contact with two adjacent edge protection elements.

Further advantages and refinements of the invention will be explained in more detail below by using the description of some exemplary embodiments and the drawing, in which:

Fig. la	shows a schematic side view of a roller mill according to an embodiment of the invention,
Fig. lb	shows a schematic longitudinal sectional illustration of a milling roller,
Fig. 2a	shows an enlarged sectional illustration of the roller mill in the transition region between circumferential surface and end face without inserted edge protection element,
Fig. 2b	shows an enlarged sectional illustration of the roller mill according to Fig. 2a with inserted edge protection element,
Figs. 3 to 9	show schematic sectional illustrations of milling rollers in the area of the edge protection elements according to various exemplary embodiments,
Fig. 10	shows a side view of a milling roller in the area of the edge protection elements with further wear protection segments, and

Figs. 11 to 14 show plan views of the edge protection elements according to various exemplary embodiments.

The roller mill illustrated in fig. 1 for the comminution of brittle material, such as limestone or ore material, has two contrarotationally driven milling rollers 1, 2, which each have a basic body 3 with a circumferential surface 4 and two end faces 5, 6, wherein the circumferential surface 4 is provided with a surface armor 7 suitable for forming an autogenous wear protection layer.

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As can be seen from figs. 2a and 2b, the surface armor of the circumferential surface 4 of the milling rollers is formed by a multiplicity of profiled bodies 12, which are held in bores in the basic body 3. The profiled bodies 12 project with one end out of the circumferential surface 4, and the distance between the profiled body is chosen such that, during operation, an autogenous wear protection layer 13 made of compressed material to be milled is formed between the profiled bodies. In the transition region between circumferential surface 4 and end face 6, in each case a circumferential recess 11 is provided (fig. 2a), which is open radially toward the circumferential surface 4 and axially toward the respective end face 5, 6 of the basic body 3. The edge protection elements 8 according to fig. 2b are held in this recess 11, so that they form a closed wear protection ring. The edge protection elements 8 have a contact surface which is configured so as to be complementary to the area of the basic body in contact therewith. In the exemplary embodiment illustrated, the pinshaped profiled body 9 is cylindrical and extends with its one end into a radial bore 10 of the basic body 3 and projects with its other end upward out of the edge protection element 8.

The pin-shaped profiled bodies 9 projecting out of the edge protection elements 8 are arranged with a similar spacing to the other profiled bodies 12 and interact with the latter to form an autogenous wear protection layer, so that an autogenous wear protection layer 13 is also formed in the areas between the pin-shaped profiled bodies 9 and the profiled bodies 12 lying radially further in. In this way, at least part of the radial outer circumferential surface of the edge protection elements 8 is also protected by the autogenous wear protection layer 13. Nevertheless, the edge protection elements 8 will expediently be formed from a harder material than the basic body 3. The edge protection elements preferably consist of a hard metal alloy.

In the following text, various exemplary embodiments of the edge protection elements will be explained by using figs. 3 to 9. In the exemplary embodiment according to fig. 3 the edge protection element 8 is provided with an additional wear

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2014331412 20 Dec 2017 protection element 14 on the side pointing toward the end face. In this case, the recess 11 is dimensioned such that both the edge protection element 8 and the additional wear protection element 14 are accommodated, the additional wear protection element ending flush with the circumferential surface 4 and the end face 6 or 5. The additional wear protection element can be designed to be wear-resistant to a particular extent, in order in particular to protect the critical edge region better. The fixing between edge protection element 8 and additional wear protection element 14 is made, for example, by means of adhesive bonding or brazing.

In the exemplary embodiment according to fig. 4 the additional wear protection element 14.1 projects axially beyond the end face 6 and, on the end face 6 of the basic body 3, the additional wear protection elements 14.1 are adjoined by further wear protection segments or strips 15.1, which are fixed to the additional wear elements 14.1 or to the basic body 3. These further wear protection segments or strips 15.1 are used for the improved protection of the end face 6. However, in this area, the wear loadings are considerably more reduced, so that, in addition to ceramic or hard metal, for example segments made of wear-resistant sheet metal are suitable as a material.

Whereas, in the previous exemplary embodiments, the profiled bodies 9, 9.1 were cylindrical, fig. 5 shows a conically formed, pin-shaped profiled body 9.2, so that the diameter of the profiled body tapers in the direction of the bore. This has the advantage that the forces acting on the profiled body 9.2 from outside are transferred to the edge protection element 8 and therefore distributed better. The additional wear element 14.2 here is formed in such a way that it projects axially further beyond the further wear protection segments or strips 15.2. In the exemplary embodiment according to fig. 6 the pin-shaped profiled body 9.3 for holding the edge protection element 8 is once more cylindrical, wherein a subregion which extends as far as into the bore is formed with a smaller diameter than the remaining region. Here, too, the forces acting on the profiled body 9.3 from outside are distributed via the edge protection element 8 to a larger area. The exemplary embodiment according to fig. 7 is distinguished with respect to the exemplary embodiment according to fig. 6 by two

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2014331412 20 Dec 2017 changes. Firstly, the additional wear protection element 14.4 projects radially beyond the edge protection element 8 and, as a result, forms a collar to limit the autogenous wear protection layer. In this case, the wear protection layer 13 can thus extend over the entire radial circumferential surface of the edge protection element 8. Furthermore, the further wear protection segment 15.4 is likewise accommodated in a cut-out in the end face 6, so that it ends flush with the end face 6.

The exemplary embodiment according to fig. 8 corresponds substantially to the exemplary embodiment according to fig. 7, without the edge, but the additional wear protection elements 14.5 are chamfered on their axially outer surface 14.51 toward the further wear protection elements or strips 15.5, so that a continuous transition results. The additional wear protection element 14.6 in fig. 9 is chamfered on its radially outer surface 14.61, so that the diameter of the milling roller tapers somewhat in its edge region.

The further wear protection segments or strips 15.1 to 15.6 can either be connected in a suitable way to the additional wear protection elements 14.1 to 14.6 and/or are fixed separately to the end faces of the basic body 3, for example by means of screws 16 or by welding (fig. 10).

Figs. 11 to 14 show various variants as to how the edge protection elements can be fixed by the pin-shaped profiled bodies 9. Here, the edge protection elements are designated by the designation 8, the additional wear protection elements by the designation 14 and the pin-shaped profiled bodies by the designation 9, as representative of all the exemplary embodiments.

According to fig. 11, each edge protection element 8 is fixed by an associated pinshaped profiled body 9. In the exemplary embodiment according to fig. 12, the pinshaped profiled bodies 9 are each arranged in the transition region between two edge protection elements 8, so that each edge protection element 8 is connected to two profiled bodies 9. If the edge protection elements 8 are designed to be longer in their length in the circumferential direction, the two exemplary embodiments according to figs. 11 and 12 can also be combined with each other, as shown in fig. 13. Of course,

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2014331412 20 Dec 2017 it is also conceivable for the edge protection elements to have different lengths in the circumferential direction, wherein the shorter elements are fixed in accordance with the exemplary embodiment of fig. 12 and the longer elements are fixed in accordance with the exemplary embodiment of fig. 13 (Fig. 14). Of course, the possible fixings indicated should not be viewed as final.

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Claims

Patent claims

1. A roller mill for the comminution of brittle material, having two contrarotationally driven milling rollers, which in each case have a basic body with a circumferential surface and two end faces, wherein the circumferential surface is provided with a surface armor suitable for forming an autogenous wear protection layer, and in each case a closed wear protection ring formed from edge protection elements is provided in the transition region between the circumferential surface and the end faces, wherein the edge protection elements comprise pin-shaped profiled bodies by means of which they are held in radial bores of the basic body, wherein on the side remote from the bores, the pin-shaped profiled bodies of the edge protection elements also project from the edge protection elements and interact there with the surface armor to form an autogenous wear protection layer.
2. The roller mill as claimed in claim 1, wherein in each case a circumferential recess open radially toward the circumferential surface and axially toward the respective end face of the basic body is provided in the transition region between the circumferential surface and the end faces, and the edge protection elements are arranged in these recesses.
3. The roller mill as claimed in claim 1, wherein the edge protection elements have a contact surface which is configured so as to be complementary to the area of the basic body in contact therewith.
4. The roller mill as claimed in claim 1, wherein the pin-shaped profiled bodies are designed to be cylindrical and/or conical.
5. The roller mill as claimed in claim 1, wherein the pin-shaped profiled bodies are formed to be the same or partially different in terms of their shape and size.

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6. The roller mill as claimed in claim 1, wherein the edge protection elements project axially beyond the end face and/or radially beyond the circumferential surface.
7. The roller mill as claimed in claim 1, wherein the edge protection elements are provided with an additional wear protection element on the side pointing toward the end face.
8. The roller mill as claimed in claim 7, wherein the additional wear protection elements project axially beyond the recess.
9. The roller mill as claimed in claim 7, wherein the additional wear protection elements project radially beyond the edge protection elements and form a collar to limit the autogenous wear protection layer.
10. The roller mill as claimed in claim 7, wherein the additional wear protection elements are chamfered on their radially outer surface.
11. The roller mill as claimed in claim 7, wherein on the end face of the basic body, the additional wear protection elements are adjoined radially inwardly by further wear protection segments or strips, which are fixed to the additional wear protection elements or to the basic body.
12. The roller mill as claimed in claim 8, wherein the additional wear protection elements project further beyond the basic body in the axial direction than the further wear protection segments or strips, and the outer boundary surface of the additional wear protection elements is chamfered as far as the further wear protection elements or strips.
13. The roller mill as claimed in claim 1, wherein the pin-shaped profiled bodies are each arranged in the transition region between two edge protection elements.

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