WEAR-RESISTANT ELEMENT FOR A COMMINUTING APPARATUS

Abstract

A wear-resistant element can be partially inserted into a recess in a surface of a wear area of a comminuting device. The wear-resistant element has a fastening region that can be connected to the recess in the surface of the wear area. The wear-resistant element may also include a wear region that protrudes at least partially from the surface of the wear area. The fastening region may comprise metal. The wear region has a shell and a core arranged inside the shell. The core is comprised of metal, and the shell is comprised of ceramic. The ceramic contains yttrium-stabilized, tetragonal polycrystalline zirconium oxide (TPZ). The TPZ makes up at least 60% by volume of the ceramic in the shell.

Claims

1.-9. (canceled)

10. A wear-resistant element configured for partial insertion into a recess in a surface of a wear area of a comminuting device, wherein the wear-resistant element comprises: a fastening region that is comprised of metal and is configured to be connected to the recess in the surface of the wear area; and a wear region that protrudes at least partially from the surface of the wear area, with the wear region including a shell and a core disposed inside the shell, wherein the core is comprised of metal and the shell is comprised of a ceramic that contains yttrium-stabilized, tetragonal polycrystalline zirconium oxide (TPZ), wherein the TPZ makes up at least 60% by volume of the ceramic in the shell.

11. The wear-resistant element of claim 10 wherein the TPZ makes up at least 80% by volume of the ceramic in the shell.

12. The wear-resistant element of claim 10 wherein the TPZ makes up at least 95% by volume of the ceramic in the shell.

13. The wear-resistant element of claim 10 wherein the TPZ makes up at least 100% by volume of the ceramic in the shell.

14. The wear-resistant element of claim 10 wherein the core extends through an entirety of the wear region.

15. The wear-resistant element of claim 10 wherein the core is fixedly connected to the fastening region.

16. The wear-resistant element of claim 10 wherein the core is integral with the fastening region such that the core and the fastening region are a one-piece construction.

17. The wear-resistant element of claim 10 wherein the shell is sleeve shaped.

18. The wear-resistant element of claim 10 wherein the fastening region comprises steel.

19. The wear-resistant element of claim 10 wherein the shell is fixedly connected to the fastening region.

20. The wear-resistant element of claim 10 wherein the fastening region makes up less than 50% of the wear-resistant element.

21. The wear-resistant element of claim 10 wherein the fastening region makes up less than 20% of the wear-resistant element.

22. The wear-resistant element of claim 10 wherein the fastening region makes up less than 15% of the wear-resistant element.

23. A comminuting device comprising: a wear area with a surface that has a recess; and a wear-resistant element that is attached at least partially in the recess, wherein the wear-resistant element comprises: a fastening region that is comprised of metal and is configured to be connected to the recess in the surface of the wear area, and a wear region that protrudes at least partially from the surface of the wear area, with the wear region including a shell and a core disposed inside the shell, wherein the core is comprised of metal and the shell is comprised of a ceramic that contains yttrium-stabilized, tetragonal polycrystalline zirconium oxide (TPZ), wherein the TPZ makes up at least 60% by volume of the ceramic in the shell.

24. The comminuting device of claim 23 wherein the fastening region is bonded substance-to-substance to a grinding roller.

25. The comminuting device of claim 23 wherein the fastening region is welded to a grinding roller.

26. The comminuting device of claim 23 wherein the fastening region is adhesively bonded to a grinding roller.

27. The comminuting device of claim 23 wherein the fastening region is soldered to a grinding roller.

28. The comminuting device of claim 23 wherein the core is integral with the fastening region such that the core and the fastening region are a one-piece construction.

29. The comminuting device of claim 23 wherein the shell is sleeve shaped.

Description

DESCRIPTION OF THE DRAWINGS

[0031] The invention is explained in more detail in the following text on the basis of several exemplary embodiments with reference to the attached figures.

[0032] FIG. 1 shows a schematic illustration of a comminuting device in a front view according to one exemplary embodiment.

[0033] FIG. 2 shows a schematic illustration of a grinding roller of the comminuting device according to FIG. 1.

[0034] FIG. 3 shows schematic illustrations of an exemplary embodiment of the wear-resistant element in a side view and a plan view.

[0035] FIG. 4 shows schematic illustrations of an exemplary embodiment of the wear-resistant element in a sectional view.

[0036] FIG. 1 schematically illustrates a comminuting device 10, in particular a roller mill. The comminuting device 10 comprises two grinding rollers, illustrated schematically as circles, having wear areas 12, 14 which have the same diameter and are arranged alongside one another. Formed between the wear areas 12, 14 of the grinding rollers is a grinding gap, the size of which can be set, for example.

[0037] During operation of the comminuting device 10, the grinding rollers rotate in opposite directions to one another in directions of rotation illustrated by the arrows, wherein grinding stock passes through the grinding gap in the falling direction and is ground.

[0038] FIG. 2 shows an end region of a grinding roller which has a wear area 12, to which wear-resistant elements 16 are attached. The wear-resistant elements 16 are attached in the outer circumference of the surface of the grinding roller. For example, the mutually spaced-apart wear-resistant elements 16, arranged alongside one another, in FIG. 2 have a circular cross section.

[0039] It is likewise conceivable for the wear-resistant elements 16 to vary in terms of size, number, cross-sectional shape and arrangement with respect to one another over the surface of the grinding roller, in order for example to compensate for local differences in wearing during operation of the comminuting device 10.

[0040] Furthermore, the grinding roller has wear-resistant corner elements 17, attached to its end, which have for example a rectangular cross section and are arranged in a row alongside one another such that they form a ring around the circumference of the grinding roller. Further cross-sectional shapes of the wear-resistant corner elements 17, which differ from the cross-sectional shape shown in FIG. 2, are furthermore conceivable. A mutually spaced-apart arrangement of the wear-resistant corner element 17 is also possible. In FIG. 2, by way of example, only the left-hand end of the grinding roller having the wear area 12 is shown, with the right-hand end, which is not shown, advantageously having an identical construction.

[0041] FIG. 3 shows a wear-resistant element 16 in a side view and a plan view. The wear-resistant element 16 has a shell 18 and a core 20, which is at least partially radially surrounded by the shell. The core 20 extends axially along the center axis of the substantially cylindrical wear-resistant element 16 to the upper end face of the wear-resistant element 16. The core 20 for example has a cylindrical form and is preferably fixedly connected to the shell 18. It is likewise conceivable that a plurality of cores 20, for example two, four or six cores 20, extend through the wear-resistant element 16, preferably parallel to one another. By way of example, the diameter of the core 20 is approximately 10 to 30% of the diameter of the wear-resistant element 16.

[0042] FIG. 4 shows a sectional view of the wear-resistant element 16 in FIG. 3. The wear-resistant element 16 has a fastening region 24 and a wear region 22, wherein the fastening region 24 is arranged in the recess 26 in the surface of the wear area 12 of the grinding roller and is connected to the wear area 12 of the grinding roller. For example, on the fastening region 24, the wear-resistant element 16 is bonded substance-to-substance, in particular welded, soldered or adhesively bonded, or connected by a form fit, in particular screwed or wedged, to the recess 26 in the surface of the wear area 12 of the grinding roller. The wear region 22 of the wear-resistant element 16 is arranged at least partially or completely outside the recess 26 in the wear area 12, with the result that said wear region protrudes from the surface of the wear area 12 in a radial direction of the grinding roller (not illustrated). In the exemplary embodiment illustrated, the fastening region 24 comprises about one third of the entire wear-resistant element 16, the wear region 22 comprising approximately the further two thirds. The fastening region 24 is preferably formed from a metal, such as for example steel.

[0043] The wear region 22 of the wear-resistant element 16 comprises the shell 18 and the core 20, the shell 18 preferably being formed from a ceramic material, such as for example tungsten carbide, titanium carbide, titanium carbonitride, vanadium carbide, chromium carbide, tantalum carbide, boron carbide, niobium carbide, molybdenum carbide, aluminum oxide, zirconium oxide, and/or silicon carbide, or a combination of the stated materials. In particular, the ceramic of the shell comprises yttrium-stabilized, tetragonal polycrystalline zirconium oxide (TPZ), wherein the TPZ comprises a proportion of the ceramic by volume of at least 60%, preferably at least 80%, in particular 95% to 100%.

[0044] Furthermore, it is also possible for particles of industrial diamonds or high-strength ceramics to be embedded in a ceramic or metallic matrix in the shell 18. The shell 18 comprises a matrix material, for example, in which a plurality of particles are arranged. The particles in question are in particular a highly wear-resistant material which comprises for example diamond, ceramic or titanium. The matrix material comprises for example tungsten carbide. The particles are bonded to the matrix material in particular substance-to-substance, for example by sintering.

[0045] During operation of the comminuting device 10, the wear-resistant elements 16 are exposed to a high degree of wear, wherein in particular the wear region 22, protruding from the surface of the wear areas 12, 14 of the grinding rollers, of the wear-resistant elements 16 becomes worn. The wear-resistant material of the wear region 22 considerably reduces the wear of the wear-resistant elements 16. Furthermore, formation of the fastening region, which is exposed to no wear or only to very little wear, from the more expensive, more wear-resistant material is dispensed with. The metal core makes it possible to remove the wear-resistant element from the recess 26 in the roller surface, even if the wear region 22 is already severely worn, by using a suitable tool to draw the wear-resistant element 16 out on the metal core 20.

[0046] The fastening region 24 is preferably formed completely from a metal and is fixedly connected to the core 20. By way of example, the fastening region 24 is adhesively bonded, soldered or welded to or is formed in one piece with the core 20.

LIST OF REFERENCE SIGNS

[0047] 10 Comminuting device/roller mill [0048] 12 Wear area/grinding roller [0049] 14 Wear area/grinding roller [0050] 16 Wear-resistant element [0051] 17 Wear-resistant corner element [0052] 18 Shell [0053] 20 Core [0054] 22 Wear region [0055] 24 Fastening region [0056] 26 Recess