CN110799269A - Vertical Roller Mill - Google Patents

Abstract

The invention relates to a vertical roller mill with a rotatable grinding bowl on which a grinding bed composed of grinding materials is formed during operation. In addition, at least two immobile, rotatable grinding rollers are provided which, in operation, roll on the grinding material, wherein the grinding material is fed to the grinding rollers by the rotation of the grinding bowl. According to the present invention, there is proposed a device for scraping off abrasive material upstream of each grinding roller, and the device is also used for removing a part of the scraped off abrasive material upstream of the grinding roller.

Description

Vertical Roller Mill

technical field

The invention relates to a vertical roller mill with a rotatable grinding bowl on which a grinding bed for grinding material is formed during operation, and at least two immovable, rotatable The grinding roller, when working, rolls on the grinding bed. The grinding material is supplied to the grinding rollers by rotating the grinding bowl around its center.

Background technique

In a typical vertical roller mill, the grinding material to be pulverized is usually fed from the center of the grinding bowl. Through the rotation of the grinding bowl, the supplied grinding material is transported from the center of the grinding bowl to the edge of the grinding bowl and accelerated in the direction of rotation by centrifugal force. The abrasive material is accelerated by the peripheral speed (ie, rotational speed) of the grinding bowl. However, since this occurs by virtue of friction at the surface, nowhere along the radius of the grinding bowl will the abrasive material reach the exact peripheral, or tangential, velocity of the grinding bowl.

In a typical vertical roller mill, there are basically three distinct streams of abrasive material. In this context they are the abrasive material flow of freshly supplied material, the abrasive material flow of rejected classifier particles, and the abrasive material flow from the internal circulation.

New abrasives refer to abrasives that have just been introduced into the grinding process. Classifier particles refer to material that is rejected by a classifier in, for example, a roll mill with an integrated classifier. The two streams of abrasive material can be fed to the center of the grinding bowl in a relatively aligned manner, ideally assuming that the rotation of the grinding bowl can create a uniform distribution over the grinding bowl. However, the grinding bed formed over the entire surface of the grinding bowl is not necessarily uniform since there is usually no constant flow of material, especially in the classifier particles and in the output of new grinding material.

In addition, the third stream of abrasive material due to internal circulation has to be considered. Internal circulation (especially of vertical roller mills operating in air circulation mode) refers to the material that is lifted to the classifier by the main air flow after falling onto the edge of the grinding table (rather than always material delivered to the classifier) falls back into the grinding bowl. Also falling into this category are abrasive materials that are transported directly away from the grinding table due to the circulating air flow or the turbulence present therein, and are redeposited.

Due to the presence of various equipment (eg grinding rolls) in a vertical roller mill, various air flows and turbulence are created, and it is not at all possible to assume that the material supplied to the grinding bowl is homogeneous.

The result of all this is that the grinding bed formed on the grinding bowl itself is not uniform or non-uniform. This means that, at different times and at various positions of the grinding bowl, especially the height of the grinding bed can vary significantly. In addition, it should be taken into account that if the grinding bowl has a raised grinding bowl rim, then the abrasive material will deliberately accumulate at the rim to some extent and create an uphill or downhill slope that results in a greater height of the grinding bed. .

For all these reasons, the grinding roll cannot be provided with a uniform flow of abrasive material with a uniform grinding bed, but instead has to be continuously adapted to various grinding bed heights by means of hydraulic damping.

Basically, three problems arise in this case.

The uneven introduction of abrasive material along the entire width of the grinding roll can result in uneven wear of the grinding roll. This is especially true where a holding edge is provided (where more material will be present).

Another problem with non-uniform grinding beds is that the surface pressure varies across the width of the grinding rolls and thus does not allow for uniform and optimal grinding.

In addition, there is a problem of vibrations generated during grinding work due to irregularities of the grinding bed. Above a certain strength, these vibrations cannot be damped by hydraulic springs, thus limiting the maximum operating speed of the grinding bowl and thus its maximum rotational speed.

A number of methods are known to partially address these problems.

One option is described, for example, in WO 2011/044966 A1. In this case, an additional preliminary roll is provided before the actual grinding roll, which serves to pre-compress the grinding material on the grinding bowl. The expected result is that a portion of the air present in the grinding bed due to its loose packing can be removed from the grinding bed and, in addition, a more uniform result when entering the grinding gap between the actual grinding roll and grinding bowl grinding bed height.

Another option for adjusting the height of the grinding bed is known from WO 2004/012693 A1. In this case there are pushers which can be used to adjust the height of the grinding bed in the area before the grinding rollers. Pushers are driven at different heights onto or into the grinding bed, and material accumulates before these pushers. In this way, the grinding bed can be adjusted to have a desired height or height distribution before the grinding rolls.

SUMMARY OF THE INVENTION

Therefore, the object of the present invention is to propose a vertical roller mill with high running smoothness.

According to the invention, this object is achieved by a vertical roller mill having the features of claim 1 .

Advantageous embodiments of the invention are described in the dependent claims and the description as well as in the drawings and description of the drawings.

In the case of the vertical roller mill according to the invention, an abrasive scraping mechanism is provided in front of the respective grinding rollers in the direction of rotation of the grinding bowl. Each of these abrasive scraping mechanisms is designed to remove a portion of the abrasive material on the grinding bowl from the grinding bowl before the corresponding grinding roller.

The basic idea behind the present invention is the realization that in general, lower energy consumption or higher productivity to achieve more efficient grinding or pulverization.

According to the present invention, this can be achieved by actively removing abrasive material from the grinding bowl by the abrasive material scraping mechanism. In contrast to the prior art, it is thereby possible that the abrasive material does not accumulate on the grinding bowl in any way, or that the abrasive material is compacted due to compression. Thereby, a very uniform flow of abrasive material can be provided to the grinding roll. Within the meaning of the present invention, "homogeneous" is understood in particular to mean a uniform height of the grinding material and a similar compression, ie the density of the grinding material on the grinding bed. Similar densities can especially be achieved by equivalent or similar pre-compression.

This uniformity allows the entire vertical roller mill system to operate at high productivity. This means in particular that the grinding bowls can be operated at higher rotational speeds than vertical roller mills without abrasive material scraping mechanisms. The grinding rollers are thus able to rotate faster and pulverize more grinding material per unit of time. Thus, the original contradiction of enabling higher productivity and higher efficiency due to active removal of abrasive material from the grinding bowl is resolved. In addition, preventing or mitigating vibrations allows related constraints on productivity and performance to be removed, or set to higher levels.

In principle, the abrasive material scraping mechanism can be designed in any desired form. Preferably, however, the abrasive scraping mechanism includes a base plate and a scraper arranged on the base plate. Advantageously, the base plate and/or the squeegee are made of ceramic or carbide, or rather they comprise the above-mentioned materials at particularly exposed parts, in order to reduce the amount of abrasive material due to scraping off or due to abrasive material under the base plate wear caused by passing through.

The advantage of the two-piece design is that the scraper can be replaced individually, which wears more than the base plate. Placing the scraper on the base plate also provides the advantage of making the grinding bed smoother in addition to the scraping action. The abrasive scraping mechanism can likewise have a one-piece design, ie with a one-piece base plate or a one-piece scraper.

In particular, efficient removal or diversion of abrasive material from the grinding bowl can be achieved by concavely concave the side of the abrasive material scraping mechanism facing away from the grinding rollers. In this case, the scraper can in particular have a plow shape. It has been shown that due to this shape, the abrasive material can be removed efficiently, or even cut away, and the entrained abrasive material flow can be easily removed from the grinding bowl. In addition, compared to other shapes, the wear caused by this shape due to the forming process is relatively minimal.

Advantageously, the abrasive scraping mechanism is designed such that the abrasive to be removed is conveyed out of the grinding bowl over the rim of the grinding bowl. If the mill is operated in air circulation mode, the grinding material removed from the grinding bowl in this way can be conveyed to the classifier by means of the circulating air flow; it can be returned to the classifier by means of an internal or external grinding cycle as rejected material Grinding bowl; alternatively, it can also be rejected by the classifier as grit and thus returned to the grinding bowl.

If the grinder is not operating in air circulation mode, pneumatic conveying back to the grinding bowl can also be employed, eg together with or independently of the feed material. Scraping and conveying excess abrasive material from the grinding bowl has proven to be the most energy efficient method for removing excess abrasive material.

Advantageously, the abrasive scraping mechanism is designed to remove abrasive material resulting in a uniform height and/or uniform density (eg, packing density) of the grinding bed formed in front of the grinding rolls. Since a uniform grinding bed with as constant a height as possible is supplied, the grinding rollers can run more smoothly and thus vibrations in the grinding machine can be reduced. The type of uniformity of the grinding bed can be considered to depend on the exact shape of the grinding bowls and grinding rolls. For example, if tapered grinding rolls and grinding bowls that are straight or flat in this area are used, the resulting grinding bed should ideally be parallel to the surface of the grinding bowl. The situation is different if spherical grinding rolls are used, in which case the grinding tracks formed on the grinding bowl are usually shaped accordingly.

In this case, it is important for the present invention that the grinding bed has a constant height, or a substantially constant or uniform height. This feature can be understood to mean that the abrasive material fed to the grinding roll has an optimum height and/or density for the grinding roll and its profile. This does not necessarily mean that it is uniform over the entire length or width of the grinding roll. Within the meaning of the present invention, the two terms "grinding table" and "grinding bowl" in relation to roller mills can be considered equivalent.

The height of the grind bed after the grind bed scraping mechanism can be any desired height. Advantageously, the aforementioned height in front of the grinding rollers, seen in the direction of rotation of the grinding bowl, is greater than the grinding gap between the grinding rollers and the grinding bowl. That is, this ensures that there is enough material in the grinding gap to be comminuted by the grinding rollers. This comminution is caused by the pressure applied by the grinding rollers in the direction of the grinding bowl. If the height of the grinding bed in front of the grinding rolls is only as high as the grinding gap, not enough grinding material can be ground. In this case, the difference between the bulk density before entering the grinding gap and the maximum compressed density within the grinding gap, where the grinding bed height before the grinding rolls and the grinding bed height in the gap and their respective is proportional to the density.

In this case it is advantageous if the height of the abrasive material scraping means is designed to be adjustable. In this way, the height of the mechanism above the grinding bowl can be adjusted, whereby the height of the grinding bed can also be changed. The height at which the abrasive material is fed to the grinding rolls can vary depending on the abrasive material to be ground and the exact design of the roll mill, whereby the respective process to be performed can be optimized.

The abrasive scraping mechanism may extend over a portion of the width of the grinding roll, or the entire width of the grinding roll. Depending on the grinding material to be pulverized and the shape of the grinding roll, it is advantageous that the grinding material scraping mechanism portion does not extend over the entire width of the grinding roll, so that a portion of the grinding bed that has not become smooth is also provided to the grinding roll . In addition, this results in reduced complexity and forces on the abrasive scraping mechanism, which means a less robust design and therefore less wear. Another advantage is that abrasive particles with a larger diameter than the distance between the abrasive scraping mechanism and the grinding bowl can be fed into the area of the grinding roller not covered by the abrasive scraping mechanism, and crushed by it.

In an advantageous embodiment, the grinding bowl comprises a holding rim for holding the grinding material conveyed from the centre of the grinding bowl to the rim of the grinding bowl due to the rotation of the grinding bowl. In this case it is preferred that the abrasive scraping mechanism extends from the retaining edge of the grinding bowl along the width of the grinding roller towards the centre of the grinding bowl.

Due to the presence of the holding edge, a slope of the abrasive material is usually formed at the holding edge which is significantly higher than the rest of the grinding bed. An abrasive scraping mechanism can be used to clear the slope by removing the slope from the grinding bowl. Given that it is significantly higher than the rest of the grinding bed, this particular slope causes uneven wear of the grinding rolls. Since the abrasive scraping mechanism clears the slope, the wear on the grinding roll will be more uniform across the width of the grinding roll. As for how it looks in vertical section, the appearance of the ramp should be reshaped from an imaginary triangle to an imaginary rectangle when entering the grinding roll gap. As experiments have shown, the energy consumption for doing so can be significantly reduced by using a plow.

The abrasive scraping mechanism may be arranged at an angle relative to the direction of rotation of the grinding bowl. In this case, the distance between the side of the abrasive scraping mechanism facing away from the grinding roll and the surface of the grinding bowl is preferably greater than the distance between the side of the abrasive scraping mechanism facing the grinding roll and the surface of the grinding bowl the distance. In other words, the abrasive scraping mechanism (especially its base plate) is angled relative to the grinding bed so that pre-compression can be performed. Pre-compression can basically be used to remove air located in the grinding bed from the grinding bed, thereby providing the grinding roll with a pre-compressed grinding bed, thereby reducing vibrations and oscillations at the grinding roll that must be damped by its damping system . Doing so allows the roller mill to run more smoothly, which in turn increases the rotational speed of the grinding bowl and increases efficiency and productivity.

Advantageously, the abrasive scraping mechanism extends as far as possible into the grinding gap, and even in the plane of the vertical projection of the grinding rollers. This can be achieved in particular with a substrate extending as far as possible, or almost as far as possible, into the grinding gap. Since the abrasive scraping mechanism or its base plate extends almost to the grinding gap, a relatively high level of reliability can be ensured to supply a uniform grinding bed to the grinding gap, and thus to the grinding rollers. If, compared to this embodiment, the grinding bed is pre-compressed relatively far before the grinding rolls, for example by using a pre-roll, then the grinding bed can be disturbed when transported from the pre-compressed location to the actual grinding roll, resulting in Not running smoothly. In this regard, in order to keep the distance between the grinding gap and the abrasive scraping means as small as possible, it is advantageous for the abrasive scraping means to extend appropriately in the plane of the vertical projection of the grinding rollers on the grinding bowl.

The ventilation of the abrasive material can also be improved by arranging on the bottom of the abrasive material scraping mechanism, in particular on the base plate, fins extending into the grinding bed substantially in the direction of rotation of the grinding bowl. These fins or projections form grooves in the grinding bed, which in this state are also ideally fed to the grinding rolls. Thereby, air in the grinding gap escaping from the grinding material due to the pressure of the grinding rollers on the grinding bowl is provided with a path through which the air can leave the grinding material. Vertical roller mills can run more smoothly since no sudden grinding bed ventilation occurs but the air can escape continuously, whereby the aforementioned roller mills can be operated at higher speeds and thus at higher productivity .

It is known to provide water injection to counteract vibrations in roller mills. Conventionally, for this purpose, water is sprayed onto the grinding bed in front of the grinding rolls to increase the density and internal friction of the grinding material, resulting in smoother operation. Advantageously, in this context, nozzles can be provided on the bottom of the abrasive scraping mechanism, in particular on the base plate, in order to introduce fluid into the grinding bed. Vertical mills are also commonly used for drying. This means that the temperature in the grinding space is usually 90°C or higher. When using water injection, it is difficult to ensure that the water is injected all the way to or into the grinding bed. In contrast to the embodiments presented here, water or other fluids are injected directly into the grinding bed. In addition, injection pressure can be used to affect the penetration depth of the fluid, resulting in a tighter and more comminuted grinding bed with lower water consumption. Lower water consumption is energy-wise because less water can have to evaporate during the mill drying process.

Description of drawings

The invention will be described in more detail below by means of illustrative exemplary embodiments and with reference to the accompanying drawings, in which:

Figure 1 shows a side view of a grinding roller with an abrasive scraping mechanism according to the present invention;

Fig. 2 shows the II-direction view in Fig. 1;

Figure 3 shows a top view of a grinding roller with an abrasive scraping mechanism according to the present invention;

Figure 4 shows a side view of a grinding roll with an abrasive scraping mechanism according to the present invention;

Figure 5 shows the V-direction view in Figure 4;

Figure 6 shows a side view of an abrasive roll with an abrasive scraping mechanism with water injection in accordance with the present invention; and

Figure 7 shows an enlarged view of the nozzle for water injection.

Detailed ways

Figure 1 shows a schematic view of the grinding roller 4 on the grinding bowl 3, and also shows the grinding material scraping mechanism 10 according to the invention.

The grinding bowl 3 rotates in the rotational direction 8 . The grinding bowl 3 generally has a circular design. The abrasive material 20 is supplied to the center of the grinding bowl, and the abrasive material 20 is moved or transported outward by the rotation of the grinding bowl 3 or the centrifugal force generated therefrom. Thus, a grinding bed 20 is formed on the grinding bowl 3 . By the rotation of the grinding bowl 3 , the grinding material 20 is fed to the grinding rollers 4 and comminuted at its grinding gap 5 by the pressure from the grinding rollers 4 and the potential additional pressure on the grinding rollers 4 .

As shown, according to the present invention, the shape of the grinding bed 20 is often not uniform, especially before the abrasive scraping mechanism 10 in the rotational direction 8 . This results in a large change in the force acting on the grinding roll 4 over time as the grinding roll 4 rolls on the grinding bed 20 . These forces can be partially attenuated by the damping system of the grinding rolls 4, but above a certain strength they also create a vertical stand of the grinding rolls 4 or the entire system (ie, the grinding bowl 3 provided with a plurality of grinding rolls 4). the so-called "vibration" of a grinder). Once the vibration occurs, the rotational speed of the grinding bowl 3 cannot be further increased, and thus the productivity cannot be further improved.

In many embodiments, the grinding system is typically designed so that the grinding bowl has a constant rotational speed. Thus, the presence of vibrations represents an upper limit to the productivity and/or the fineness of the abrasive material. This means that a given system cannot achieve the desired value or further increase the productivity and/or fineness. However, if the use of the abrasive scraping process results in reduced vibration in the overall process, new equipment with higher grinding bowl rotational speeds and higher productivity can be planned and proposed.

The abrasive scraping mechanism 10 according to the present invention may be used in order to prevent or reduce vibration. With respect to the direction of rotation 8 of the grinding bowl 3 , the aforementioned mechanism is located before the grinding roller 4 . In the embodiment shown here, the abrasive scraping mechanism 10 comprises two basic components, which may have a two-piece design, but may also have a one-piece design. First, a scraper 14 can be provided that can remove, or scrape, the abrasive material 22 that has accumulated on the grinding bed 20 beyond the height _h1 from the grinding bed 20 . This is clearly shown in FIG. 2 , from which it follows that the removed grinding material 23 is conveyed out of the grinding bowl 3 .

Second, a base plate 12 is also provided, and the scraper 14 is fixed on the base plate 12 . The base plate 12 extends as far as possible towards the grinding gap 5 between the grinding roll 4 and the grinding bowl 3 . The grinding gap 5 can be considered as the point or area where the distance between the grinding roll 4 and the grinding bowl is minimal.

The bottom of the base plate 12 may extend substantially parallel to the grinding bowl 3 , whereby the abrasive scraping mechanism 10 may also extend substantially parallel to the grinding bowl 3 . However, the abrasive scraping mechanism 10 may also be arranged slightly inclined such that the distance h1 between its side facing away from the grinding roller 4 and the upper surface of the grinding bowl 3 is greater than the distance _h1 between its side facing the grinding roller 4 and the grinding bowl The distance between the upper surfaces of the 3 is greater. In Figure ₁ , the latter distance is referred to as h2.

If the abrasive scraping mechanism 10 is arranged at an angle, ie at an angle α with respect to a line parallel to the surface of the grinding bowl 3, the abrasive 22 forming the grinding bed 20 can be slightly pre-compressed. This means in particular that ventilation takes place. In this context, aeration is understood to mean that the air in the grinding bed 20 due to the loose packing of the grinding material 22 is removed from the grinding bed 20 and causes the particles to be more densely packed. This in turn results in a more uniform force on the grinding roll 4, resulting in a smoother operation.

As can be seen in particular from FIG. 1 , the scraper 14 has a plow-like design. This can be seen again in conjunction with FIG. 2 . In this case it has been found to be advantageous for the scraper 14 to have a concave shape, which is preferably designed such that the above-mentioned shape conveys the abrasive material 23 that has been scraped off the grinding bowl 3 over the edge of the grinding bowl .

Although not clearly shown in FIG. ₁ , the abrasive scraping mechanism is suspended in a flexible manner, so that the heights hi and _h2 are adjustable. This is preferred because different heights hi and h2 are optimal depending _on the production rate and the abrasive material ₂₂ used. It is essential here, however, that the height h ₂ is always greater than the height of the grinding gap 5 , ie the height h ₃ . Otherwise, the productivity of the abrasive material 22 will be lowered.

In the following, other advantages of the abrasive scraping mechanism 10 according to the present invention will be explained with reference to FIG. 2 , which shows a view from arrow II in FIG. 1 .

In FIG. 2 , the retaining edge 6 can be seen at the edge of the grinding bowl 3 . Abrasive material 22 moving outwardly from the center of the grinding bowl 3 towards the edge of the grinding bowl 3 accumulates at said edge and results in a ramp 25, which is also referred to as an abrasive material wedge. In a similar manner, the ramp or upper ramp 25 is positioned towards the centre of the grinding bowl 3 as the material 22 is introduced there and is transported outwards towards the edge of the grinding bowl 3 only due to the rotation, thereby dispersing.

As shown in FIG. 2 , the abrasive scraping mechanism 10 begins near the retaining edge 6 . Thus, the wedges 25 of abrasive material at the retaining edge 6 can be removed, and thus the buildup, removed from the grinding bed 20, resulting in the most uniform and consistent grinding bed 20 possible on which the grinding rollers 4 roll.

3, 4 and 5 illustrate another embodiment of the abrasive scraping mechanism 10 according to the present invention. In this context, FIG. 3 shows a top view of the grinding roll 4 . Figure 4 shows a side view of the grinding roller 4 with the abrasive scraping mechanism 10 according to the invention. Finally, the V-direction view of FIG. 4 is shown in FIG. 5 .

In the embodiment shown here, fin-like projections 16 are provided on the bottom of the base plate 12 , which are pressed into the grinding bed 20 . These projections 16 thus press into the air escape grooves 31 in the grinding bed 20 . The purpose of these grooves is to allow the air displaced by the grinding bed 20 compressed in the grinding gap 5 to escape. In this case, in order to prevent the generated air escaping groove 31 from being filled with abrasive material 22 again, it is important that the abrasive material scraping mechanism 10 or the fins 16 or the fin-like protrusions are as close as possible to the grinding gap 5, But they terminate just before said gap to make room for escaping air. In another embodiment, the fin-like protrusions 16 may also have a hollow interior with channels that open into the space above the bottom plate for selectively venting air.

Finally, Figures 6 and 7 show another embodiment of the abrasive scraping mechanism 10 according to the present invention. In this case, a side view of the grinding roller 4 is shown again in FIG. 6 . Figure 7 shows an enlarged view of the nozzle 25 for water injection provided in this embodiment.

After the scraper 14 , one or more nozzles 35 are provided in the substrate 12 , which nozzles communicate with a supply line 37 . Fluid, especially water, can be introduced directly into the grinding bed 20 via this supply line 37 . This is especially useful to further displace any trapped air and increase the density of the grinding bed. Water injection is a known means for preventing or reducing vibration during operation of a vertical roller mill. An advantage of the embodiment shown here is that by injecting the water directly into the grinding bed 20, it is ensured that the water enters the grinding bed 20 without substantial losses.

Vertical roller mills are usually used for grinding drying, in which case the temperature in the grinding space is 90°C or higher. In this case, if the water is simply sprayed or atomized, there is a fundamental problem in that there is no guarantee that the water will actually enter the grinding bed 20 and remain there. By injecting directly before the grinding gap 5, the water is less likely to have evaporated. A smaller amount of water is advantageous in terms of energy because less water has to be evaporated during the grinding drying process.

Also shown in the embodiment shown here is a protective ceramic layer 33 for reducing wear on the substrate 12 and the squeegee 14 .

Therefore, with the vertical roller mill and abrasive scraping mechanism according to the present invention, very smooth operation can be achieved, thereby increasing productivity.

Claims (15)

1. Vertical grinder with: a rotatable grinding bowl (3) on which, in operation, a grinding bed (20) of abrasive material (22) is formed, and at least two immovable, rotatable grinding rollers (4), which roll on a grinding bed (20) during operation, Wherein, the grinding material (22) is supplied to the grinding roller (4) by the rotation of the grinding bowl (3), It is characterized in that, an abrasive scraping mechanism (10) is provided in front of each grinding roller (4) with respect to the direction of rotation (8) of the grinding bowl (3), and Each abrasive scraping mechanism (10) is designed to remove a portion of the abrasive material (22) located on the grinding bowl (3) from the grinding bowl (3) before the corresponding grinding roller (4). 2 . The vertical roller mill according to claim 1 , wherein the abrasive material scraping mechanism ( 10 ) comprises a base plate ( 12 ) and a scraper ( 14 ) arranged on the base plate ( 12 ). 3 . . 3. The vertical roller mill according to claim 1 or 2, characterized in that a side of the abrasive material scraping mechanism (10) facing away from the grinding roller (4) has a concave shape. 4 . The vertical roller mill according to claim 1 , wherein the abrasive material scraping mechanism ( 10 ), in particular the scraper ( 14 ), has a plow shape. 5 . 5. Vertical roller mill according to any one of claims 1 to 4, characterized in that the abrasive material scraping mechanism (10) is designed such that the abrasive material (22) to be removed can It is conveyed out of the grinding bowl (3) over the edge of the grinding bowl (3). 6. The vertical roller mill according to any one of claims 1 to 5, characterized in that the abrasive material scraping mechanism (10) is designed to remove abrasive material (22) at the grinding roller (4) A grinding bed (20) having a uniform height (h ₂ ) is previously formed. 7. Vertical roller mill according to any one of claims 1 to 6, characterized in that, with respect to the direction of rotation of the grinding bowl (3), after the abrasive scraping mechanism (10) The height (h ₂ ) of the grinding bed is greater than the grinding gap (5) between the grinding roller (4) and the grinding bowl (3). 8. The vertical roller mill according to any one of claims 1 to 7, characterized in that the height of the abrasive scraping mechanism (10) is designed to be adjustable so that the setting of the The height of the abrasive scraping mechanism above the grinding bowl (3). 9. A vertical roller mill according to any one of claims 1 to 8, characterized in that the abrasive scraping mechanism (10) extends over a part of the width of the grinding roller (4), or Extends over the entire width of the grinding roll (4). 10. Vertical roller mill according to any one of claims 1 to 9, characterized in that the grinding bowl comprises a retaining edge (6). 11. Vertical roller mill according to any one of claims 1 to 10, characterized in that the abrasive material scraping mechanism (10) is removed from the retaining edge (6) of the grinding bowl (3) ) extends along the width of the grinding roller (4) towards the center of the grinding bowl (3). 12. The vertical roller mill according to any one of claims 1 to 11, wherein the abrasive material scraping mechanism (10) is relative to the rotation direction (8) of the grinding bowl (3) Set at a certain angle, the distance (h 1 ) between the side of the abrasive scraping mechanism facing away from the grinding roller (4) and the grinding bowl (3) is greater than the distance (h ₁ ) of the abrasive scraping mechanism. The distance between the side facing the grinding roller (4) and the grinding bowl (3). 13. The vertical roller mill according to any one of claims 1 to 12, characterized in that the abrasive material scraping mechanism (10) is arranged to extend as far as possible to the grinding gap (5), and Extends in the plane of the vertical projection of the grinding roll (4). 14. The vertical roller mill according to any one of claims 1 to 13, characterized in that, on the bottom surface of the abrasive material scraping mechanism (10), in particular on the base plate (12), a Fins (16) projecting into the grinding bed (20) extend substantially in the direction of rotation (8) of the grinding bowl (3). 15. The vertical roller mill according to any one of claims 1 to 14, characterized in that, on the bottom surface of the abrasive material scraping mechanism (10), in particular on the base plate (12), a Nozzle (35) to introduce fluid into the grinding bed (20).

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