JP2016528038A - Vertical roller mill - Google Patents

Abstract

The present invention relates to a vertical roller mill comprising a driven crushing table and at least two stationary crushing rollers on a crushing layer. In order to improve the energy efficiency, instead of the classification basket installed in the upper housing area as before, the step of providing a smaller classifier near each grinding roller is carried out, whereby the ground grinding The material transport distance is greatly reduced. In addition to this, a guide unit for overmilled crushed material is created, which greatly prevents recirculation of the fine particles.

Description

  The invention relates to a vertical roller mill according to the preamble of claim 1.

  A vertical mill or vertical roller mill is well known (WO2005 / 028112A1, DE3100341A1). The vertical mills disclosed therein have a classification basket in the upper region of the mill housing, which rotates about a vertical axis and is carried upwards in an air stream. To separate.

  In view of processing, such vertical mills are required to have higher throughput, so that the size of components such as a crushing table, a crushing roller, and a classification basket is further increased. Thus, because of their size, the components can no longer be manufactured as a single unit, they can only be manufactured as subdivided units, which can be combined or united when they arrive at the place where the vertical mill is used. Must be welded.

  Apart from these surfaces, it is possible, for example, to blow hot air as conveying and drying gas through an annular gap, and in particular the pulverized particles exceed the total height of the vertical mill into the classification basket. In order to be able to be carried upwards, more and more gases and corresponding fans are also required.

  Another vertical mill (DE19718668C2) facilitates the separation and discharge of components of a material mixture that is difficult to disperse, and has a horizontal classifier that rotates around a horizontal axis in the upper region of the mill housing Thus, the fine particles from the pulverization and classification process are easily discharged.

  Thus, it is believed to be already known to use one or more horizontal classifiers in a vertical mill.

International Publication No. 2005/028112 German Patent Application Publication No. 3100341 German Patent Invention No. 19718668

  However, from an energy point of view, such a configuration involves carrying the crushed crushed particles to a horizontal classifier installed in the upper region far beyond the overall height of the vertical mill housing. In order to be able to do so, there is also the problem of supplying a large amount of gas for transporting these particles.

  Therefore, it is an object of the present invention to provide a vertical mill and particularly a vertical roller mill, even if the vertical mill is increased in size and increased in throughput, in particular the components of the classifier as one unit or as a plurality of units. It is feasible and is designed to avoid a substantial increase in the energy resources required for the gas for particle transport and drying.

  This object is achieved according to the invention through the features of patent claim 1. Advantageous embodiments of the invention are claimed in the dependent claims.

  An important core idea of the present invention is that it significantly shortens the transport path to the classifier of the crushed crushed particles so as not to increase the amount of energy required for the required pressure and amount of gas. Seen in.

  This is achieved by placing a smaller classifier, in particular a horizontal classifier or a slightly inclined classifier, in the vicinity of the rollers, instead of a classification basket located in the upper region of the mill housing. .

  Another important idea of the present invention is that it arranges a guide unit for finer crushed particles that are carried upwards in the air stream to guide the crushed material crushed by the grinding roller. As can be seen, this guide unit facilitates a spiral supply to each horizontal classifier.

  In a vertical roller mill designed in this way with a rotary grinding table and at least two stationary grinding rollers rotating on the grinding layer, the energy utilization is therefore more efficient with respect to the required transport and drying gas. Or as a result of such a smaller classifier having a smaller horizontal classifier structural unit or an inclined axis of rotation arranged in the vicinity of the roller, energy savings are realized.

  Combined with a corresponding horizontal classifier and a curved guide unit to better carry the crushed particles carried upwards in the airflow, the internal recirculation of the crushed crushed particles is sometimes reduced Can be avoided or energy savings can be realized.

  A wind classifier or horizontal classifier and a guide unit are advantageously assigned to each grinding roller, so that recirculation flow is largely avoided.

  However, instead of individually assigning the horizontal classifier to each roller, it is possible to realize that the flow of the rising gas and the crushed particles of, for example, two rollers are merged. Therefore, in the case of a mill having four crushing rollers, a configuration with two horizontal classifiers can be envisaged, and each horizontal classifier is assigned to two crushing rollers combined.

  Improvements in flow are also realized by shifting each air classifier in front of each grinding roller. In terms of structure, the staggered arrangement of the wind classifier can therefore be seen with respect to the vertical axis passing through the center of each grinding roller as shown in FIG. 1, which is the ground ground material behind the grinding roller. Executed in the direction of. Placing each air classifier offset with respect to the corresponding crushing roller means that the crushing particles of the crushed crushing material behind the crushing roller, so to speak, are finer crushing that is conveyed upwards in the air stream. It is advantageous in that it can be better captured by the guide unit for the material and can be fed in a more targeted way to the assigned horizontal classifier.

  In order to improve the transport of the crushed particles transported upward, the guide unit is configured as a curved guide plate or as a collection channel that extends while curving, supplying the particles in a spiral to the classification basket of the wind classifier To do. From a hydrodynamic point of view, it makes it possible to supply the crushed particles in the same rotational direction as the corresponding basket of the wind classifier at a relatively short distance, so that good classification of the crushed particles is possible. It becomes.

  As long as a curved recovery channel is provided to carry the crushed particles upwards, the cross section of the channel is reduced in the direction towards the air classifier, thereby increasing the flow rate in this region and the centrifugal force acting on it. Some sort of pre-classification for coarse materials is realized. This coarse material, together with coarse particles rejected by the classifier of the wind classifier, is transferred to a recirculation unit located under the wind classifier and fed again to the grinding process. The recirculation unit is advantageously formed as a funnel-shaped cone so that the rejected coarse material is again fed to the recirculation unit inclined towards the center, preferably approximately in the center of the grinding table. Is done.

  The arrangement of wind classifiers or horizontal classifiers can be connected in a structurally simple manner via a common inner central discharge line for gas-particulate flow, so that the supply pipes connect the gas-particulate stream. Enough to carry to downstream units such as cyclones or dust filters.

  Depending on the overall design of the vertical mill, each air classifier can be provided with a separate outward discharge line for the classified gas-particulate mixture. By dividing in this way, the crushed particles can be separately prepared into different desired classifieds.

  Regardless of incorporating multiple wind power or horizontal classifiers, this configuration of a vertical mill allows for a central supply of crushed material, which, regardless of multiple wind classifiers, requires no additional cost resources. There seems to be no.

  Such a vertical mill, in which the classifiers are arranged horizontally or inclined, in particular each assigned to a grinding roller, therefore shortens the transport path for the ground ground particles. To help. The milling process and the energy resources required for this can be greatly improved with the solution according to the invention, in particular the vertical height of the vertical mill is smaller and lower, and the recirculation of the milled shredder particles is reduced. This is because it is avoided as much as possible. A wind classifier used horizontally or inclined improves the classification of material particles compared to a stationary classifier in the upper region of a vertical mill.

  By shortening the transport path of the crushed crushed particles upwards, even if there is a flared ring in the annular gap around the pulverization table, the amount of gas and the required pressure can be reduced. Savings are possible.

It is a figure which shows the vertical roller mill by this invention roughly fractured | ruptured partially.

  The invention is explained in more detail below using schematic embodiments.

  FIG. 1 shows a partial cutaway view of a vertical mill area of a vertical classifier disposed in the vicinity of a crushing table and crushing rollers installed on the crushing table. The partial cutaway view shown here is a view in which the range of about 90 ° that can show the range of about 140 ° into which the entire two crushing rollers enter is broken. The grinding roller in which the inner surface can be seen is shown in line with the rotational axis of the grinding table. In the left part of FIG. 1, the side view of the second grinding roller is located in the edge region of the grinding table. It is shown with a swing arm and an annular gap shown schematically.

  The detailed cross section shows the vertical roller mill 1 with a sectoral break of approximately 90 ° between the vertical axes of two adjacent grinding rollers 4 offset by approximately 90 °. Thus, the overall sector break is somewhat larger, about 140 °.

  In the lower region, the grinding table 2 is shown with a direction of rotation D around its axis of rotation 3. Two crushing rollers 4 are installed on the crushing table 2, and the crushing rollers 4 shown to coincide with the rotation axis 3 in the plane of the figure are shown as seen from the inside to the outside. The crushing roller 4 arranged in the left region of the roller mill 1, i.e. the left half, is shown in a side view and is directed towards the crushing roller suspension via a conical roller shell and a rocking arm.

  An annular gap 17 is provided around the outer edge of the grinding table 2 in the radial direction. The annular gap 17 generally has a blade ring, and is used to blow a conveying and drying gas 19 as an air current.

  The crushed material 13 to be pulverized, which can be supplied to the center, is supplied to the pulverizing roller 4 by the rotation D of the pulverizing table 2, and is pulverized by the pressure of the pulverizing roller and the shearing force generated thereby, The crushed crushed material is behind the pulverizing roller 4 (left).

  The newly supplied crushed material 13 and the crushed crushed material 14 form a mixture constituting the pulverized layer 15 in the outer region of the pulverizing table 2 in an actual pulverizing process.

  In order to avoid repeated overrolling of the pulverized pulverized material or respective excessive pulverization, according to the invention, as much part of the amount of fine particles and crushed particles as possible of each pulverizing roller 4 It is supplied directly to the corresponding wind classifier 7 through the air flow 19 blown into the gas-crushed particle mixture 21 rising behind.

The crushing roller 4 disposed stationary causes a rotational motion _DW in the same direction as the crushing table 2 due to the friction lock between the force and the crushing layer 15.

  According to the invention, a smaller air classifier 7 having a horizontal axis 9, or possibly an inclined axis, is shifted in the rotation direction D of the grinding table 2 in the vicinity of each grinding roller 4. It is designed to be installed. The corresponding horizontal classifier 7 and the rotationally driven classifier basket 8 thus acquire the ground crushed material carried upwards in the air flow 19 at a relatively short distance.

  Therefore, a large amount of high pressure air flow 19 is required to transport the gas-crushed particle mixture across the entire mill mill chamber to a classifier basket located in the upper region of the mill housing. Don't be.

  According to the present invention, in addition to shortening the distance by arranging the air classifier 7 in the vicinity of the crushing roller 4, for example, a guide unit 26 as a guide plate 26 or a collection channel 27 is further installed. The rising gas particle stream is therefore recovered through this guide unit 25 and can be guided in a targeted manner, with a curved design in the direction of and around the wind classifier 7. Supply is further improved. The reduction in the cross section of the guide channel 27 also contributes to this. The ascending gas-crushed particle mixture 21 is therefore fed to the wind classifier 7 in the same direction of rotation as the wind classifier itself, so that fine particles and rejected coarse material are well classified in the classification basket 8. The

  The fine particles classified in the classification basket 8 are then guided outwardly as fine particles 29, in particular by pneumatic guidance, as shown on the left side of FIG. 1, where they are fed to the central supply pipe or from the center. It is possible to supply to downstream units such as cyclones or filters on individual lines that are disconnected.

  The illustrated air classifier 7 has a horizontal rotation axis. An inclined axis of rotation is also possible, in which case the fine particles are more likely to be ejected outward by inclining the axis of rotation towards the center of the grinding table. On the contrary, if the rotation axis of the wind classifier 7 is inclined in the direction of the suspension of the corresponding crushing roller 4 and the swing arm, the classified fine particles can be easily discharged to the upper region in the center of the roller mill. Central discharge of fine particles is possible.

  The funnel-shaped cone 31 is provided as a unit that recirculates the material to the substantially central region of the grinding table 2 for recirculation of the rejected coarse material 32.

The arrangement of the wind classifier 7 in the vicinity of the grinding roller 4 and the structure of the vertical roller mill according to the present invention in combination with the guide unit 25 thus enables a highly efficient grinding process, which This is because recirculation is greatly prevented. In addition to this, the short path between the pulverized layer and the existing air classifier 7 can reduce the amount of gas for conveyance and the pressure of the gas. Similarly, the investment required for the installation of the entire roller mill according to the invention is also kept low by the low configuration mode of this vertical mill compared to conventional vertical mills.

Claims (12)

A driven crushing table (2) and at least two stationary crushing rollers (4) rolling on a crushing layer (15) of crushed material (13);
An annular gap (17) for blowing a gas (19) for enclosing the grinding table (2) and conveying and / or drying the crushed particles (21) of the crushed crushed material;
A plurality of wind classifiers (7) for classifying the crushed particles (14) carried upward in the flow of gas (19) into fine particles (29) and recirculated coarse material (32);
Have
In a vertical roller mill (1) in which the wind classifier (7) is arranged to have a basically horizontal (8) or inclined classifier axis,
An air classifier (7) is installed above the vicinity of the crushing roller (4), and supplies the crushed particles (14) carried in the air stream (21) to the wind classifier (7). A vertical roller mill characterized in that at least one guide unit (25) is assigned to each grinding roller (4). The roller mill according to claim 1,
A roller mill, wherein an air classifier (7) and a guide unit (25) are assigned to each crushing roller (4). The roller mill according to claim 1 or 2,
Each roller classifier (7) is installed by being shifted from the vertical axis passing through the center (5) of each crushing roller (4) in the direction of the crushed crushed material (14). In the roller mill according to any one of claims 1 to 3,
The guide unit (25) has a curved guide plate (26) or a curved collection channel (27) and supplies the crushed particles (14) in a spiral fashion to the classification basket (8) of the wind classifier (7). A roller mill characterized by The roller mill according to claim 4, wherein
Roller mill, characterized in that the curved collection channel (27) is formed such that the channel cross-section decreases towards or around the air classifier (7). In the roller mill according to any one of claims 1 to 5,
The guide unit (25) has an inflow region of the collection channel (27) for the crushed particles (14, 19) at the height of the upper region of the grinding roller (4), each grinding roller (4) A roller mill provided in a rear region of the roller. In the roller mill according to any one of claims 1 to 6,
A roller mill characterized in that the direction of flow of the crushed particles (14, 19) coincides with the direction of rotation of the air classifier (7) in the region of the guide unit (25). In the roller mill according to any one of claims 1 to 7,
Roller mill characterized in that each wind classifier (7) has a recirculation unit (31) for rejected coarse material (32) inclined towards the center (3) of the grinding table (2) . The roller mill according to claim 8, wherein
A roller mill, characterized in that the recirculation unit (31) is formed as a funnel-shaped cone. In the roller mill according to any one of claims 1 to 9,
A roller mill, characterized in that the wind classifier (7) is connected to the inner central discharge line for the classified gas-particulate mixture (29) leaving the wind classifier (7). In the roller mill according to any one of claims 1 to 9,
A roller mill, characterized in that the wind classifier (7) has a separate outward discharge line for the classified gas-particulate mixture (29). In the roller mill according to any one of claims 1 to 11,
Roller mill characterized in that central crushed material is supplied.

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