KEY GRINDING PLATE SEGMENT, GRINDING PLATE SEGMENT SYSTEM AND METHOD THEREOF

Abstract

The invention relates to a replaceable key grinding plate segment for a grinding track of a roller mill grinding plate, wherein the grinding track has an annular shape with an outer and an inner circumference around a central point. The length of the inner edge of the key grinding plate segment closest to the central point is greater than the length of the outer edge farthest from the central point. The invention also relates to a system of grinding plate segments, a roller mill, and a method for replacing grinding plate segments.

Description

KEY GRINDING PLATE SEGMENT, GRINDING PLATE SEGMENT SYSTEM AND METHOD THEREOF FIELD OF INVENTION The invention relates to a key grinding plate segment for a grinding track of a roller mill grinding plate. Here, the grinding track has an annular shape with an outer circumference and a smaller inner circumference around a central point. The replaceable key grinding plate segment has an outer edge and an inner edge, as well as two connecting edges that join the outer and inner edges. Furthermore, the invention relates to a system of grinding plate segments for a grinding track of a roller mill grinding plate, comprising a plurality of standard grinding plate segments of the same size and shape, each having an inner and an outer edge connected by two connecting edges. The length of the inner edge is shorter than the length of the outer edge. Finally, the invention also relates to a method for removing grinding plate segments from a grinding plate with a grinding plate segment system. BACKGROUND OF THE INVENTION Common roller mills have a grinding plate that rotates beneath stationary, rotatably mounted grinding rollers. The grinding plate has a grinding track on which the grinding rollers roll. During operation, the material to be ground is located between the grinding plate or grinding track and the grinding rollers. The grinding rollers act by the force of their own weight, but are sometimes also subjected to an additional force, so that they press against the grinding track and, therefore, against the grinding plate. During operation, wear occurs on both the grinding rollers and the grinding track due to the forces generated and the abrasion of the material being ground. For this reason, the grinding track is designed to be replaceable in most mills. PRR7. ίΠ / 77Ω7 / Β / ΥΙΛΙ rollers. Typically, annular grinding tracks have interchangeable segments of the same size, shaped somewhat like a slice of pie. This means they are trapezoidal and longer at their outer edge than at their inner edge. Specifically, both the outer and inner edges form an arc, a result of the track's annular design. However, it is also possible to design the inner and outer edges straight, giving the grinding track a polygonal shape that approximates an annular form. A grinding plate is often also referred to as a grinding table or grinding plate. Similarly, grinding plate segments are also called grinding table plates or plate segments. The problem with common grinding plate segment systems is their replacement. During operation, the rolling of the grinding rollers on the grinding track causes the material being ground to be pressed into the space between the segments—that is, the region where two adjacent segments touch. Although every effort is made to make this space as low and small as possible, the considerable forces generated during the grinding process cannot prevent the material to be ground, especially material already ground to a very small size, from penetrating it. Due to the forces during grinding, this penetrated ground material solidifies and is compressed very strongly, thus hardening. To replace the grinding plates, it's now necessary to remove one segment first, and then the others. However, this first segment cannot be pulled inwards, as this is geometrically impossible due to the standard design with a larger outer edge and a smaller inner edge. It's typically not possible to push the grinding plate outwards because of the design of most grinding plates. Usually, the grinding plate segment is lifted upwards by trying to press it from below after removing a retaining ring that secures the segments to the grinding plate. PRR7. ίΠ / 77Ω7 / E / YΙΛΙ However, this is very difficult due to the pressed material to be ground, so removing the first segment usually takes several hours or even days. It is not unusual for the edge or joint between two adjacent grinding plate segments to be machined here by flame cutting with the aid of a so-called grooving plane. Generic grinding plate segments of the type in question can be found, for example, in DE 1507629 or DE 1507580. BRIEF DESCRIPTION OF THE INVENTION Therefore, the object of the invention is to provide a grinding plate segment, a grinding plate segment system, and a method for replacing grinding plate segments that facilitate the replacement process. This object is achieved according to the invention by means of a key grinding plate segment having the features of claim 1, a system of grinding plate segments having the features of claim 6, and a method having the features of claim 15. The beneficial embodiments of the invention are indicated in the dependent claims and in the description, as well as in the figures and their explanation. In the key grinding plate segment according to the invention, the length of the inner edge closest to the center point is provided to be greater than the length of the outer edge furthest from the center point. The invention is based on the fundamental concept of deviating from the conventional method used to date. The replaceable key grinding plate segment is dimensioned such that, when pushed towards the center point of the grinding plate, it no longer becomes stuck due to its geometric shape, thus allowing the key grinding plate segment to be removed. Another advantage of this design is that the space between the key grinding plate segment and its connecting edges with neighboring grinding plate segments is automatically widened, or problems caused by solidified material being ground are minimized or do not occur. Beneficially, the outer edge of the key grinding plate segment forms a circular arc on the outer circumference and the inner edge of the plate segment 0RR7. The key grinding segment forms a circular arc on the inner circumference of the grinding plate. In other words, the dimensions of the key grinding plate segment fit the grinding track of the grinding plate, where, however, the tip is missing. Furthermore, the length of a circular arc formed by the key grinding plate segment can decrease as the radius from the inner edge to the outer edge increases. Therefore, the shape of the key grinding plate segment is similar to an inverted slice of cake. It is preferable to provide a pressure cavity on the outer edge of the key grinding plate segment to accommodate a press for the replacement process. A pressing tool can be applied through this pressure cavity to press the key grinding plate segment in the direction of the grinding plate's center point. The pressing tool can be positioned between the pressure cavity and the edge of the main body of the grinding plate. In a beneficial configuration, the pressure cavity is designed to be covered during operation with a retaining rim component. This means it is designed, if possible, to prevent the material being ground from being pressed into the pressure cavity. In the context of the invention, the term "during operation" can be understood as a roller mill that is ready for use. This means, in particular, that the grinding plate is fully assembled, at least on the mill side; that is, a grinding track with a retaining edge is present. The invention further relates to a system of grinding plate segments for a grinding track of a roller mill grinding plate, comprising several grinding plate segments, each with an inner and an outer edge. The two edges are connected by two connecting edges. The length of the inner edges is less than the length of the outer edge. Therefore, the standard grinding plate segments have a shape similar to a slice of pie, but without the pointed end. According to the invention, the abrasive plate segment system is further provided to comprise at least one key abrasive plate segment according to the invention and at least one compensating abrasive plate segment disposed adjacent to the PRR7. ίΠ / 77Ω7 / Β / ΥΙΛΙ key abrasive plate segment. By providing a key grinding plate segment in a grinding plate segment system, it is possible that the grinding plate, which is constructed from the grinding plate segment system, or the rolling surface of the rollers can be replaced relatively easily without the need for the time-consuming removal and crushing of material from the joints as previously described in the prior art. It is beneficial that the grinding plate segments are formed as standard grinding plate segments of the same size and shape, and the key grinding plate segment and at least one compensating grinding plate segment together form the shape of one or more standard grinding plate segments. By sizing the key replaceable grinding plate segment and providing an offset grinding plate segment, which together form the shape of one or more standard grinding plate segments, all other standard grinding plate segments can be configured in the same way. This simplifies inventory management and means that fewer different grinding plate components need to be stocked. Conventional segments can also continue to be used for this purpose. Grinding plate segments may also be referred to as grinding plates. Preferably, two compensating grinding plate segments are provided in an arrangement to the left and right of the key grinding plate segment. In this case, the two compensating grinding plate segments can be designed substantially mirror-symmetric with respect to an axis at the grinding plate radius through the key grinding plate segment. This axis can be, for example, the axis of symmetry at the radius of the key grinding plate segment. This design makes it easier to achieve the size of one or more standard grinding plate segments with one key grinding plate segment and two compensating grinding plate segments. This is further simplified by providing symmetrically constructed compensating grinding plate segments. Preferably, two compensating grinding plate segments with the Γ«β7 ίη / 77Ω7 / Β / YΙΛΙ key grinding plate segments have the size of one, two or three standard grinding plate segments. In another configuration, the grinding plate segments can also be configured as compensating grinding plate segments. In this case, several key grinding plate segments are provided. It is preferred here that an equal number of compensating grinding plate segments and key grinding plate segments be provided. In other words, each key grinding plate segment is followed by a compensating grinding plate segment. Standard grinding plate segments, as described above, are no longer used in this configuration. According to this configuration, it is also possible to consider the compensating grinding plate segments as a combination, as described in the previous configuration, of standard grinding plate segments with compensating grinding plate segments, provided they are formed as a single piece.In this case, you only need to have two different types of grinding plate segments. Another advantage is that several key grinding plate segments are provided, so the position in which the grinding plate stops relative to the grinding rollers above it is irrelevant. Otherwise, care must be taken to ensure that the key grinding plate segment does not stop in the region of a roller, as this would complicate disassembly and ideally require further rotation of the plate. It is advantageous that the grinding plate segments—that is, the standard grinding plate segments, the key grinding plate segments, and / or the compensating grinding plate segments—can be secured to the grinding plate by means of a one-piece or multi-piece retaining ring. According to the design, the retaining ring is intended to bear against the inner circumference of the grinding track, that is, against the inner edge of the grinding plate segments, thereby pressing the grinding plate segments outward against an edge of the grinding plate base or main body. The invention further relates to a roller mill with a grinding plate, wherein the grinding plate comprises a system of grinding plate segments according to the invention. PRR7 Vf\l77(\7iaiWrA A roller mill of this type has the advantage that when the grinding track, i.e., the individual grinding plate segments, is replaced and reinstalled, this can be done much faster than with conventional grinding plate segments. This is because the key grinding plate segment can be removed from the grinding track very easily, and it is hardly necessary to remove the material to be ground that has accumulated at the edge between the key grinding plate segment and the adjacent segments before removing the key grinding plate segment. Finally, the invention also relates to a method for removing a grinding plate segment from a grinding track of a roller mill grinding plate having a grinding plate segment system according to the invention. In this case, the retaining ring and the deflector ring of the grinding plate are first removed. This opens the pressure cavity of the key grinding plate segment according to the invention. A pressure tool can then be applied to the pressure cavity, and the key grinding plate segment can be pressed toward the center of the grinding plate. The main body of the grinding plate acts as a counter bearing. The space where the key grinding plate segment is pressed was previously occupied by the retaining ring. After removing the key grinding plate segment, the remaining grinding plate segments can be removed. Here too, it is not necessary to first clean the solidified material to be ground from the edge or groove between two adjacent grinding plate segments, as there is never an additional grinding plate segment on one side, and therefore a slight sliding motion on that side provides sufficient clearance. BRIEF DESCRIPTION OF THE FIGURES The invention is explained below by means of a schematic embodiment and with reference to the figures, in which: Figure 1 shows a schematic plan view of a grinding plate with a grinding track according to a first modality; Figure 2 shows a schematic plan view of a grinding plate with a grinding track according to a second modality; and Γ«β7 ίη / 77Ω7 / Β / ΥΙΛΙ Figure 3 shows a cross-sectional view through a grinding plate with a grinding track. DETAILED DESCRIPTION OF THE INVENTION Figure 1 shows a schematic top view of a grinding plate 4 with a grinding track 5 according to a first embodiment. The grinding track 5 comprises one key grinding plate segment 10, two mirror-shaped compensating grinding plate segments 11, and ten standard grinding plate segments 12. The key grinding plate segment 10 has an outer edge 31, an inner edge 32, and two connecting side edges 33. Similarly, the standard grinding plate segments 12 also have an outer edge 41, an inner edge 42, and two connecting edges 43. The same is also true for the two offset grinding plate segments 11, which have an outer edge 51, an inner edge 52, and two connecting edges 53. As shown in Figure 1, the outer edge 31 of the key grinding plate segment 10 according to the invention is shorter than its inner edge 32. This allows the key grinding plate segment 10 to be pushed into the center of the grinding plate 6. As an expert in the field can see, this offers the advantage that by pushing the key grinding plate segment 10 inwards, the clearance between the connecting edges 33 of the key grinding plate segment 10 and the adjacent connecting edges 53 of the compensating grinding plate segment 11 is increased. This also means that the material to be ground pressed here cannot prevent the key grinding plate segment from being pushed inwards. Together with the two adjacent compensation grinding plate segments 11, the key grinding plate segment 10 is the size of two standard grinding plate segments 12. This means that standard items can be used for the rest of the grinding track. Figure 2 shows an alternative embodiment of grinding plate 5. Only the differences with respect to the embodiment according to Figure 1 will be discussed below. The grinding plate 5 according to this embodiment has, by way of example, six CRR7. iP / 77Ω7 / B / YILI key grinding plate segments 10 and, as an example, six compensating grinding plate segments 11. These are arranged alternately on the grinding plate 5. As can be seen in combination with the modality of Figure 1, the standard grinding plate segments 12 are omitted here. However, in contrast to the modality according to Figure 1, only two different types of grinding plate segments are used. This simplifies stock maintenance. Another advantage of this modality is that the first key grinding plate segment 10, which is removed by pushing it towards the center 6 of the grinding plate, can be freely selected. This is particularly interesting because in an unfavorable case, when the mill stops, a key grinding plate segment 10 could end up directly under the roller, requiring the mill to be restarted.In the mode according to Figure 2, this is much less likely, since the pitch of the grinding plate segments is much greater than the number of grinding rollers. Figure 3 shows a cross-sectional view through a grinding plate 4. Here, a pressure cavity 15 is shown in the right region of the key grinding plate segment 10. This is covered by a retaining rim 26. The position of the retaining rim 26 ensures that almost nothing, or at least very little, material to be ground enters the pressure cavity 15 during operation, i.e., during the grinding processes. The key grinding plate segment 10 is arranged and secured in a notch in the grinding plate body 7 by means of a clamping ring 20. To install the grinding track 5, the key grinding plate segment 10 is inserted, then the clamping ring 20 is positioned. This is secured by means of a screw 21. Due to its wedge shape, the clamping ring presses the key grinding plate segment 10 against the outer edge of the abrasive plate when the screw 21 is tightened. The other grinding plate segments 11, 12 are similarly secured before or after this. For removal, this process is carried out in reverse order. It is essential that the key grinding plate segment 10 be removed first, before the other grinding plate segments 11 and 12. To do this, screw 21 is loosened first, allowing the retaining ring 20 to be removed. Simultaneously, either before or after, the retaining ring is also removed. PRR7. iΠ / 77Ω7 / B / YILI deflector 26. A pressure tool can then be inserted into the pressure cavity 15, and the key grinding plate segment 10 can therefore be pressed into the space where the clamping ring 20 was previously located. After the key grinding plate segment 10 has been removed, the other grinding plate segments 11, 12 can also be removed with relative ease. With the key grinding plate segment according to the invention, the grinding plate segment system according to the invention, as well as the method according to the invention, it is possible to significantly simplify the replacement of the grinding plate segments of a grinding track of a roller mill and carry this out in a shorter time.

Claims

1. A grinding plate segment system for a grinding track (5) of a grinding plate (4) of a roller mill having several grinding plate segments (12), each having an inner edge (42) and an outer edge (41), which are connected by two connecting edges (43), wherein the length of the inner edge (42) is less than the length of the outer edge (41), having at least one key grinding plate segment (10) interchangeable for the grinding track (5) of the grinding plate (4) of the roller mill, wherein the grinding track (5) has an annular shape with an outer circumference and a smaller inner circumference around the center point, having an outer edge (31) and an inner edge (32), as well as two connecting edges (33) connecting the outer and inner edges,wherein the length of the inner edge (32) closest to the center point is greater than the length of the outer edge (31) furthest from the center point, and having at least one compensating grinding plate segment (11) arranged adjacent to the key grinding plate segment (10), characterized in that the length of a circular arc formed by the key grinding plate segment (10) decreases as the radius from the inner edge (32) to the outer edge (31) increases, so that the shape of the key grinding plate segment (10) is similar to an inverted piece of cake.

2. The grinding plate segment system (10) according to claim 1, further characterized in that the outer edge (31) of the key grinding plate segment (10) forms a circular arc on the outer circumference and the inner edge (32) of the key grinding plate segment (10) forms a circular arc on the inner circumference.

3. The grinding plate segment system according to claim 1 or 2, further characterized in that a pressure cavity (15) is provided on the outer edge (31) for the placement of a pressure tool for a PRR7 replacement process.

4. The grinding plate segment system according to claim 3, further characterized in that the pressure cavity (15) can be covered with a retaining edge component (26) during operation.

5. The grinding plate segment system according to any one of claims 1 to 4, further characterized in that the grinding plate segments (12) are configured as standard grinding plate segments (12) of the same size and shape, and in that the key grinding plate segment (10) and the at least one compensating grinding plate segment (11) together form the shape of one or more standard grinding plate segments (12).

6. The grinding plate segment system according to claim 5, further characterized in that two compensating grinding plate segments (11) are provided to the left and right of the key grinding plate segment (10).

7. The grinding plate segment system according to claim 6, further characterized in that the two compensating grinding plate segments (11) are substantially symmetrical with respect to an axis in the radius of the grinding track through the key grinding plate segment (10).

8. The grinding plate system according to any one of claims 5 to 7, further characterized in that two compensating grinding plate segments (11) and one key grinding plate segment (10) are the size of one, two, or three standard grinding plate segments (12).

9. The grinding plate segment system according to any one of claims 1 to 4, further characterized in that the grinding plate segments (12) are configured as an offset grinding plate segment (11) and in that several key grinding plate segments (10) are provided.

10. The grinding plate segment system according to any one of claims 1 to 4 or 9, further characterized in that it is provided with the same number of compensating grinding plate segments (11) and key grinding plate segments (10)· PAR7 ίη / 77Ω7 / Β / YΙΛΙ 11. The grinding plate segment system according to any one of claims 1 to 10, further characterized in that the key grinding plate segment (10), the compensating grinding plate segment (11) and / or the standard grinding plate segments (12) can be fixed to the grinding plate (4) by means of a one- or multi-piece clamping ring (20).

12. A roller mill comprising a grinding plate (4), characterized in that the grinding plate (4) has a system of grinding plate segments according to one of claims 1 to 11.

13. A method for removing grinding plate segments (10, 11, 12) from a grinding plate (5) having a grinding plate segment system according to any one of claims 1 to 11, further comprising a retaining ring (20) and a deflector ring (26), characterized in that the retaining ring (20) and the deflector ring (26) are removed, a pressure tool is attached to a pressure cavity (15) of the key grinding plate segment (10), the key grinding plate segment (10) is pressed in the direction of the center of the grinding plate by means of the pressure tool, and the other grinding plate segments (11, 12) are subsequently removed.

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