HK1202090B - Press roll for a roll press - Google Patents

Description

Press roll for a roller press

Technical Field

The invention relates to a press roll for a roller press, in particular for the comminution of highly abrasive materials, comprising a roll body which (for wear protection in the edge region) has a plurality of pocket-like recesses distributed over the circumference and spaced apart from one another in the tangential direction or in the circumferential direction on one or both roll edges, which recesses are each formed open laterally and on the top, wherein in each case only one hard body is inserted as an exchangeable edge protection element into the respective pocket-like recess.

Background

A roller press usually has two press rollers. Roller presses are used to a particular extent for crushing and in particular for crushing coarse mineral material, such as ore, cement clinker, slag, kimberlite, coal or ceramic raw material, under high pressure. Such roller presses are also referred to as material bed mills. The invention also includes a roller press for compacting or briquetting materials.

In the treatment and in particular the crushing of brittle, granular material with such a roller press, high forces occur and the roller surface is heavily loaded, so that in practice the wear protection of the roller surface is of particular significance. It is known in practice to use cylindrical hard metal pins or studs which are "raked" into corresponding blind holes in the roller body and form a naturally occurring wear protection layer together with the material to be ground pressed in, for wear protection of the roller surface (see EP 0516952 a 1). However, such wear protection is often unsatisfactory in the region of the roller edge, since the risk of breaking off of the pin in the edge region is great. For this reason, special measures have already been proposed for edge protection or for wear protection in the edge region of the roll.

EP 0516952 a1 thus discloses a generic press roll in which not only cylindrical hard metal pins for wear protection are introduced into the roll body, but also pocket-like recesses are provided at the roll edges, which are each formed so as to be open laterally and upwardly, wherein plate-shaped, wear-resistant material pieces are introduced into the pocket-like recesses. The distance of these edge protection elements in the roller circumference direction corresponds approximately to the distance of the node pins incorporated in the remaining roller regions. The wear protection achieved in this way in the edge region is however unsatisfactory.

For this reason, alternative edge protection configurations are proposed, in which replaceable edge protection elements are embedded in a circumferential annular shoulder which is open laterally and at the top.

Thus EP 1502650B 1 describes a press roll comprising recesses in the form of circumferential annular shoulders arranged on the roll edge, wherein a plurality of wear protection elements are arranged one behind the other in the circumferential direction in each of these recesses. In this way, the wear protection element made of hard metal forms a closed-like ring, which is intended to provide a high wear protection. The wear protection element can be fastened directly in the circumferential annular shoulder by means of gluing, clamping or welding. Usually, the wear protection elements are fastened in a surrounding gap in a closely successive manner, so that no naturally occurring wear protection between the elements is formed either.

A similar applies to the pressure rollers or grinding rollers known from EP 1684907B 1 for pressure-crushing granular material, wherein, for edge protection, a plurality of hard bodies are arranged on the side edges of the roller segments in a circumferential annular shoulder of the roller shell, wherein these hard bodies project both axially from the end faces and radially from the surface of the roller shell.

An alternative wear protection is described in EP 0659108B 1. The wear layer of the press roller has substantially planar regions made of a highly wear-resistant material, which may be formed, for example, by tiles or ceramic tiles. The gaps between the highly wear resistant zones are filled with another wear resistant material. The tiles or tiles may be manufactured, for example, from a metal matrix composite by hot isostatic extrusion. These prefabricated hard bodies are then permanently fastened together with the gap material to the base body by hot isostatic pressing.

Disclosure of Invention

Starting from the initially explained prior art, the object of the present invention is to provide a press roll for a roller press, which is characterized by a particularly robust, but nevertheless replaceable wear protection at the roll edge.

In order to solve this problem, the invention teaches, in a generic press roll of the type mentioned at the beginning with individual pocket-like recesses at the roll edge, that the length of the pocket-like recesses and the length of the embedded edge protection elements are greater in the tangential or circumferential direction than the distance between two directly adjacent recesses.

The invention is based on the recognition that it is advantageous in principle to equip the pressure roller with replaceable and therefore releasable edge protection elements on the roller edge. Releasable means in the context of the present invention that these edge protection elements can be removed from the recesses without destruction for replacement purposes. In this connection, in addition to screw connections and form-locking connections, also connections by means of adhesive or welding are also included, since, for example, these connections can be released again by heating. According to the invention, however, the releasable edge protection element is now not arranged in the circumferential groove or annular shoulder, but rather in the individual pocket-like recesses, wherein in each case only one hard body is releasably inserted as a replaceable edge protection element in each of the individual pocket-like recesses. In contrast to the known solutions with circumferential annular shoulders, the solution according to the invention has the advantage that, despite the very high pressing forces, the individual edge protection elements do not touch and therefore cannot abut or press against one another either. Damage to the individual edge protection elements, and more precisely also damage by breaking, which is basically a concern in brittle hard materials, is thereby avoided. The arrangement of the edge protection elements in the respective locally defined pocket has the advantage, inter alia, that the edge protection elements are supported not only on the underside and on the inside, but also laterally on the stepped shoulder. Because of the design of the roll edge with the respective partially defined pocket, the individual recesses are separated from one another by "separation webs", so that the edge protection elements are supported tangentially by these separation webs. The high pressures occurring can be dissipated into the matrix well. Finally, the solution according to the invention has the advantage over the known arrangements with a circumferential collar that a naturally occurring wear protection can be formed in the region of the separation bridge and thus in the region between the respective pocket and the edge protection element, which protects the edge of the embedded wear protection element to a particular extent. The naturally occurring wear protection can thereby be formed not only in the remaining roll region but also in the edge region and between the individual edge protection elements. This results in that wear of the brush in these areas is avoided. In the known solutions with circumferential collar shoulders, there is the problem that, in particular in the region of the connection points of the individual segments, erosion can lead to material being pressed into the occurring recesses. This results in a bending being exerted on the element, which then, in particular in the case of edge protection elements made of hard metal, can lead to the brittle element breaking off.

The pocket-like recess is, as explained, formed so as to be open laterally and at the top. Lateral opening in the context of the present invention means opening at the end face in relation to the roller, which means opening on the side facing away from the roller center in the axial direction. In the context of the present invention, open at the top means open on the side facing away from the roller axis in the radial direction. This is discussed in detail in the description of the figures.

Although the inventive press roll, deviating from the known concept of using a circumferential collar, works with laterally and upwardly open pockets, is characterized by a reliable edge protection over the entire circumferential area of the press roll. Since the (tangential) length of the pocket-like recess and thus also of the embedded edge protection element is (significantly) greater in the circumferential direction than the (tangential) distance between two directly adjacent recesses and thus significantly greater than the thickness of the separation bridge arranged between the respective recesses. Preferably, the length of the recess and the length of the edge protection element are more than twice, preferably more than five times, particularly preferably more than ten times, the distance between the individual pockets. The relatively small distance between the recesses compared to the length of the recesses furthermore has the advantage that a naturally occurring wear protection can also be formed without problems in the edge region. The separation bridges between the interspaces provide however sufficient stability in order to achieve the advantages already described. For this purpose, the invention provides in a preferred further development that the (tangential) distance of two directly adjacent recesses is more than 3mm, preferably more than 4 mm.

The edge protection elements provided in the respective pockets may have the most geometrically different shapes. Edge protection elements are preferably used which are formed at an angle, for example rectangular, in a plan view onto the roll surface. In this case, it is within the scope of the invention for the edge protection elements to also be formed at an angle, for example rectangular, in a side view onto the roller, so that the edge protection elements can have the shape of a right parallelepiped, for example. However, the invention alternatively also encompasses other geometric edge protection elements, which may also have a non-angular shape, in particular in top view.

Particularly preferably, edge protection elements are used which are shaped differently from a right parallelepiped. In this case, the invention preferably provides that the lateral recess has, in a side view, at least in regions, a curved wall and that the edge protection element has, at least in regions, a curved outer contour adapted to the curved wall. In this way, the (locally) curved wall of the recess and the (locally) curved outer contour can be formed in a circular arc shape in cross section or alternatively also in a parabolic shape in cross section. In any case, the already described lateral support of the edge protection element and thus the dissipation of the pressure into the main body can be optimized thereby. Furthermore, such a pocket with curved wall or bottom regions can be introduced into the base body particularly easily, for example by milling.

The advantages according to the invention can be achieved with edge protection elements made of very different materials. It is thus within the scope of the invention for the edge protection element, which is detachably inserted into the pocket-like recess, to be made of hard metal or a hard metal-like material, for example cermet. However, it is preferred that an edge protection element made of a Metal Matrix Composite (MMC) material may be used within the scope of the invention. These edge protection elements made of MMC have the advantage over edge protection elements made of hard metal that they can be constructed less brittle and are therefore less sensitive to bending by suitable selection of the base material, the proportion of which is significantly higher in an MMC than in a hard metal. Furthermore, the possibility of "setting" the wear also exists due to the selected material composition. In practice, it has hitherto been a problem that the pressure in the region of the roll edges is generally lower than in the region of the roll center. This results in the edge protection element wearing out more slowly and the roller thereby becoming "thinner" or acquiring a "concave" geometry in the roller center. This may in extreme cases be to such an extent that the material in the centre of the roll is not sufficiently crushed. These disadvantages can be avoided, for example, by using suitable edge protection elements made of a metal matrix composite material having wear characteristics and wear rates that are compatible with the respective use case. Metal matrix composites refer to materials in which hard particles are integrated into a continuous metal matrix, wherein the hard particles are disposed within the composite separately from one another by the continuous metal matrix. Such an edge protection element made of a metal matrix composite is preferably manufactured by sintering and/or hot isostatic pressing extrusion. In the finished material, the non-metallic hard particles are distributed and surrounded by the metallic material of the metallic matrix. The metal matrix composite is therefore distinguished in particular by a relatively small proportion of hard particles from the hard metal. The hard particles of the metal matrix composite are furthermore significantly larger than the hard particles of the hard metal. It is preferred in the context of the present invention to use metal matrix composites in which hard particles having a size of more than 20 μm, for example more than 40 μm (preferably more than 60 μm), and a volume content of less than 50% (preferably less than 40%) are used, which hard particles are (discontinuously) embedded in a (continuous) metal matrix. Respectively, the volume content in the (extruded) hard body.

In principle, it is within the scope of the invention for the edge protection element to be formed as a substantially homogeneous solid body, for example made of hard metal, cermet or MMC. In an alternative preferred embodiment, however, the edge protection elements can have a composite construction and in each case have a bearing element with a wear layer arranged thereon, wherein the bearing element is made of a ductile material having a lower hardness than the wear layer. This embodiment has the advantage that the support element can be produced from a well-machinable material, for example steel, which in particular enables an optimum fastening of the edge protection element to the roller body. The wear layer itself then forms wear protection. The wear layer of the edge protection element can be made, for example, of hard metal or a hard metal-like material, for example cermet, or-as already stated-of a Metal Matrix Composite (MMC). The wear layer is fixedly connected to the support element during the manufacture of the edge protection element, for example by sintering and/or Hot Isostatic Pressing (HIP).

The wear layer applied to the support element may cover the entire surface of the support element and thereby form the entire surface of the edge protection element. Alternatively, however, the wear layer may cover only a partial region of the support element. This makes it possible, for example, to produce a recess in the support element, into which recess the wear layer is then integrated in the manner of a wear insert.

The edge protection element is according to the invention releasably fastened to the roll body, so that the edge protection element is in principle exchangeable. Such fastening is for example achieved by a threaded connection. For this purpose, the edge protection element can have suitable passages, for example holes, through which corresponding fastening elements, for example screws, can be introduced into the roller body. Such a construction is particularly contemplated when the edge protection element has a support element made of a ductile material, for example steel. Alternatively, it is also within the scope of the invention to fasten the edge protection element (releasably) in the pocket by means of an adhesive or welding joint. Alternatively or additionally, a form-locking connection of the edge protection element in the pocket can also be realized, and more precisely, for example, by a "dovetail connection". For this purpose, the edge protection element can be equipped with a (for example dovetail-shaped) form-locking bridge which engages in a form-locking manner in a corresponding female die in the pocket.

The separating bridges arranged between the individual interspaces or pockets may have a constant thickness in the axial direction. However, alternatively the thickness may vary over the width of the void. The thickness of the separating bridge can thus increase or decrease from the roll edge in the direction of the roll centre.

In order to further optimize the fastening of the edge protection elements in the pockets and/or the introduction of the pressing force into the roll body, the recesses and the edge protection elements can each have a cross section which expands at least in regions in the direction of the roll center. The cross section can thus be expanded or partially expanded from the direction of the roll end sides in the direction of the roll center, so that the (inner) faces of the edge protection elements in each case in the axial direction are larger towards the center of the roll than towards the (outer) faces of the roll end faces. The contour of the recess or pocket is correspondingly "negative". In this way, the edge protection element itself is positively connected to the roller on its outer contour, so that the edge protection element is secured against falling out during the assembly process.

The subject matter of the invention is not only the press roll itself but also, in a preferred further development, a roll press comprising two such press rolls.

The press roller can furthermore be designed as a solid roller, i.e. the roller body is designed as a solid body. Alternatively, the roll body may also have a (cylindrical) basic body and a shell arranged thereon, so that the wear protection is then fitted on/in said shell.

The pocket-like recess can be produced, for example, by machining, in the base body, i.e. in the solid body or in the sleeve, with the formation of the bridge.

Drawings

The invention will be further explained with the aid of the drawings, which show only exemplary embodiments. Showing:

FIG. 1 is a perspective view (in part) of a first embodiment of a press roll according to the invention;

fig. 2 shows a second embodiment of a variant of the subject matter of fig. 1;

fig. 3 shows a third embodiment of a variant of the subject matter according to fig. 1 and

FIG. 4 is a cross-section of a variant embodiment of the invention;

figure 5 is another alternative of the present invention.

Detailed Description

In the figures, a press roll 1 for a roller press is shown in each case, in particular for high-pressure comminution of brittle, mineral material. The roller press usually comprises two press rollers 1, of which only a part is shown in the figure, however. Such a pressure roller 1 can, as is shown in the figures, be designed as a solid roller, the roller body 2 then being designed as a solid body. However, alternatively the roll body may also have a base body and a shell surrounding the base body. This is not shown in the figures.

Such a press roll is in any case equipped with a suitable wear protection, which can be constructed in various ways. The diagrams in the figures are restricted to the wear protection measures in the region of the (end-side) roll edges.

For wear protection in the region of the roll edges, the roll body 2 has a plurality of pocket-like recesses 3 distributed over the circumference and spaced apart from one another in the circumferential or tangential direction T on one or both roll edges. The individual pocket-like recesses 3 are separated from one another in the circumferential direction T by a separating web 4. The recesses are open both laterally and at the top. In each pocket-like recess 3, a single hard body is detachably inserted as an exchangeable edge protection element 5. The figures show the pressure roller 1 in a partially assembled state, i.e. for better understanding some of the recesses 3 are shown without embedded edge protection elements.

Fig. 1 also shows a circumferential or tangential direction T, an axial direction a and a radial direction R. As already explained, the individual pocket-like recesses 3 are open both laterally and at the top. Lateral opening therefore means opening at the end face, i.e. on the side facing away from the roller center in the axial direction a. Open at the top means open on the side facing away from the roller axis in the radial direction R.

The known circumferential collar on the edge of the roll is therefore dispensed with in the embodiment according to the invention. Instead, the respective pocket-like recess and thus the receiving pocket 3 are provided, into which in each case only a single edge protection element 5 is inserted. The length L of the pocket-like recess and also the length L of the embedded edge protection element 5 is greater than the distance a between two directly adjacent recesses 3. The length L, l and the distance a are in this case in relation to the circumferential direction T of the roller and more precisely in the region of the outer, upper edge of the edge protection element. The distance a between the individual pockets 3 thus corresponds to the thickness of the bridge 4 provided between the interspaces 3 and thus also between the edge protection elements 5, which bridge is part of the roller body 2. The pocket-like recess 3 is thus introduced in the roller body 2, for example by machining.

The embodiment according to the invention comprising the individual pockets 3 results in that the individual edge protection elements 5, which are designed as hard bodies, do not abut and cannot be pressed against one another despite the high forces occurring, so that damage to the edge protection elements is avoided. In addition, the pressure occurring can be introduced into the roller body 2 without problems by means of this embodiment. This applies in particular to the embodiment shown in the figures, in which the lateral recess 3 has a curved wall or bottom region 3a in a side view and the edge protection element 5 has a curved outer contour 5a, wherein the curved outer contour 5a is adapted to the curved wall region 3 a. In the exemplary embodiments according to fig. 1 to 3, both the curved wall region 3a and the curved outer contour 5a are each (partially) cylindrically formed.

Fig. 1 shows a first embodiment in which the edge protection element 5 is produced "uniformly" from one and the same material. It may for example be a hard body made of hard metal or a hard metal-like material, such as a cermet. Alternatively, the hard body can also be made of a metal matrix composite. In the exemplary embodiment shown in fig. 1, the edge protection element or hard body 5 is fastened in the recess without screws, for example by gluing or welding.

Fig. 2 shows in an alternative embodiment an edge protection element 5, which has a support element 5b and a wear layer 5c arranged thereon in each case as a composite structure. The support element 5b is made of a ductile material, for example steel. Whereby the support element 5b is used first to fasten the edge protection element 5 in the interspace 3, while the wear layer 5c determines the edge protection or wear properties. For this purpose, the wear layer 5c can be produced, for example, from hard metal or a hard metal-like material (e.g., cermet) or preferably also from a metal matrix composite. In this case, it is advantageous to fasten the wear layer to the support element 5b by sintering and/or hot isostatic pressing. In the scope of production, therefore, the edge protection elements 5 each with the bearing element 5b and the wear layer 5c are prefabricated and then assembled in the recess 3.

Fig. 2 shows an embodiment in which the edge protection element 5 is fastened to the roller body 2 by means of screws. The edge protection element 5 therefore has suitable passages 6 or holes, through which screws can be introduced into the roller body 2. In the exemplary embodiment shown in fig. 2, the holes 6 for the screws are provided in the region of the support element 5 and thus in the region of the extensible material.

Fig. 3 shows an alternative embodiment in which the edge protection element 5 is fastened to the roller body 2 in a form-fitting manner, and more precisely by means of a dovetail arrangement. For this purpose, the edge protection elements 5 each have an assembly bridge 7 and grooves 8, which extend in the radial direction in the region of the respective recess 3, are provided in the roller body 2, wherein both the assembly bridge and the grooves 8 can be designed in the form of a dovetail. Despite this form-fitting connection, it may be expedient to additionally fasten the edge protection element 5 in the recess 3 by means of gluing or soldering.

Alternatively, as shown in fig. 3, the element 5 can also be formed as a composite component comprising a wear layer 5c and a bearing element 5b, the wear layer 5c forming a wear insert 5c which is introduced into a prepared recess of the bearing element 5 b.

The edge protection element 5 shown in the figures is of rectangular design in plan view onto the roller. In a side view onto the end side of the roller, however, the edge protection element 5 is, in this embodiment, as illustrated, partially rounded. The invention also encompasses embodiments in which the edge protection element is polygonal, for example rectangular, in a side view from the end side, so that, for example, a right-angled parallelepiped edge protection element can also be realized. This is not shown in the figure.

It is also within the scope of the invention for the edge protection element to be provided with a curved contour on the upper side alternatively or additionally, in order to adapt to the radius of curvature of the roller in particular. This alternative is not shown.

It is also within the scope of the invention, as explained, that the recess 3 and the edge protection element 5 have a cross section which expands at least partially in the direction of the roll center. This alternative is shown by way of example in fig. 4 and 5. Fig. 4 shows an embodiment in which the lower wall region 3a, in axial section, descends from the roll edge in the direction of the roll center, so that a sloping lower edge is formed. The same applies to the corresponding lower outer contour 5a of the edge protection element 5. This embodiment has the effect that the edge protection element is reliably pressed into the recess by the occurring pressing force. Such embodiments can be implemented in various ways in connection with the edge protection element, for example also in the case of the edge protection element shown in fig. 1 to 3. The same applies to the alternative shown in fig. 5. The recess 3 and the edge protection element 5 also have a cross section which expands at least in some areas in the direction of the roller center, this being the lateral wall region or the lateral outer contour in fig. 5. The content on which fig. 4 is based can therefore also be provided in the lateral regions of the recess according to fig. 5, wherein these possibilities can also be combined with one another.

Claims (15)

1. A press roll (1) for a roller press, comprising a roll body (2), the roller body has a plurality of pocket-like recesses (3) distributed over the circumference and spaced apart from one another in the circumferential direction (T) on one or both roller edges, which recesses are each formed so as to be open laterally and upwardly, wherein only one hard body is embedded in each pocket-shaped recess (3) as an exchangeable edge protection element (5), characterized in that the length (L) of the pocket-like recess (3) in the circumferential direction in the region of the outer, upper edge of the edge protection element and the length (L) of the embedded edge protection element (5) in the circumferential direction (T) in the region of the outer, upper edge of the edge protection element are greater than five times the distance (a) between two directly adjacent recesses (3) in the region of the outer, upper edge of the edge protection element.

2. A press roll (1) according to claim 1, characterized in that the length (L) of the interspace (3) in the circumferential direction in the area of the outer upper edge of the edge protection element and the length (L) of the edge protection element (5) in the circumferential direction (T) in the area of the outer upper edge of the edge protection element are more than ten times said distance (a) between two directly adjacent interspaces in the area of the outer upper edge of the edge protection element.

3. A press roll (1) according to claim 1 or 2, characterized in that the distance (a) between two directly adjacent interspaces (3) in the area of the outer, upper edge of the edge protection element is more than 3 mm.

4. A press roll (1) according to claim 1 or 2, characterized in that the edge protection element (5) is rectangular in a top view of the roll.

5. A press roll (1) according to claim 1 or 2, characterized in that the lateral gap (3) has an at least partially curved wall surface (3a) in a side view and the edge protection element (5) has at least partially a curved outer contour (5a) adapted to said curved wall surface (3 a).

6. A calender roll (1) as claimed in claim 5, wherein the curved wall surfaces (3a) of the recesses (3) and/or the curved outer contour (5a) of the edge protection elements (5) are formed in the shape of a circular arc or a parabola or a hyperbola.

7. The press roll (1) according to claim 1, characterized in that the edge protection elements (5) each have a support element (5b) comprising a wear layer (5c) arranged thereon, wherein the support elements are made of an extensible material having a hardness that is less than the hardness of the wear layer (5 c).

8. A press roll (1) according to claim 1 or 7, characterized in that the edge-protecting element (5) or its wear layer (5c) is made of hard metal or cermet or Metal Matrix Composite (MMC).

9. A press roll (1) according to claim 7, characterized in that the supporting element (5b) is made of steel.

10. A press roll (1) according to claim 7, characterized in that the wearing layer (5c) is fastened to the support element (5b) by sintering and/or pressing with Hot Isostatic Pressing (HIP).

11. A press roll (1) according to claim 1 or 7, characterized in that the edge protection element (5) or the support element (5b) of the edge protection element is releasably fastened to the roll body (2) by screwing, gluing, welding.

12. A press roll (1) according to claim 1 or 7, characterized in that the edge protection element (5) is releasably fastened to the roll body (2) by means of a form-locking connection.

13. A press roll (1) according to claim 1 or 2, characterized in that the distance between two tangentially adjacent interspaces (3) decreases or increases from the roll edge in the direction of the roll centre.

14. A press roll (1) according to claim 1 or 2, characterized in that the gap (3) and the edge protection element (5) each have a cross-section which expands at least locally in the direction of the roll centre.

15. Roller press comprising two press rollers according to one of claims 1 to 14.