DE102019210047B3 - Vertical roller mill - Google Patents

Abstract

The present invention relates to a vertical roller mill with a driven plate (1) rotatably mounted about an axis of rotation for transporting regrind (2), a feeding device for feeding the regrind (2) onto the plate (1), and at least one roller ( 3), the roller (3) with the plate (1) forming a grinding gap (4), the material to be ground (2) on the plate (1) forming a grinding bed (5) which the grinding gap (4) by rotation of the plate (1) can be fed, an installation (6) for venting and compressing the grinding bed (5) and for evening out a height of the grinding bed (4) fed to the grinding gap (4) in front of the grinding gap (4) in the transport direction of the grinding bed (5). 5) is provided, the installation (6) having a compression element (7), the distance from which the roller (3) facing the surface (8) of the plate (1) is variable. In order to provide a vertical roller mill in which, despite changing properties of the regrind, the most constant possible operation of the mill with a uniform and well-prepared grinding bed for the grinding in the grinding gap is proposed, it is proposed that the vertical roller mill has - at least a measuring device (9) for measuring forces acting on the installation (6), - a control and regulating device (10) for evaluating measuring signals from the measuring device (9) and for generating an actuating signal for actively adjusting the distance of the compression element (7) from the surface (8) of the plate (1) facing the roller (3) as a function of the measurement signals of the measuring device (9) - an adjusting device (11) by means of which the distance of the compression element (7) from that of the roller (3) facing surface (8) of the plate (1) depending on the control signal of the control and regulating device (10) is adjustable.

Description

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

In a vertical roller mill, the ground material in the grinding gap between the (grinding) roller and the (grinding) plate is stressed and crushed. The regrind consists of the feed material and the sometimes much finer circulating material (classifier and external circulation). The ground material is fed into the grinding gap at high speed by the rotating movement of the grinding plate and then comminuted in the grinding gap. The condition of the grinding bed has a decisive influence on the shredding process between the roller and the grinding track. Time-varying material accumulations in front of the roll (bow waves) have a negative impact on the introduction of grinding force and compressive stress.

From the EP 3 238 824 A1 is a vertical roller mill with the features of the preamble of claim 1 is known. In this mill, an installation (scaper 13) is provided in the transport direction of the ground material in front of the grinding gap, which is formed between the roller and the plate. The installation has the function of compressing the ground material, venting it and achieving a uniform bed height. Installation according to EP 3 238 824 A1 is a passive arrangement by means of which a pressing force that is set once via a weight can be exerted on the regrind. The installation has a support arm (support beam 14), on which a compression element (scaper body 15) is arranged via movable support elements (movable support members 20). The compaction element is pressed onto the regrind with a predetermined force by means of a weight (weight 21). In this way, the compression element exerts a constant passive force on the regrind, which leads to compression and deaeration of the regrind. This force cannot be adapted to changing properties and / or compositions of the grinding stock during operation of the mill.

A disadvantage of the known vertical roller mill is therefore that the effect of the installation cannot be flexibly adapted to changing operating conditions of the mill and in particular changing conditions with respect to the regrind, because in the known device the contact pressure of the compression element is influenced by the weight initially set once and cannot be adjusted quickly and as required if the grist composition changes during operation of the mill.

During the operation of the mill, the material properties (e.g. particle size composition, ...) of the material to be ground on the grinding plate and the grinding track change constantly. Despite the changing properties of the regrind, mill operation should be as uniform and optimized as possible.

Disadvantage of the from the EP 3 238 824 A1 known passive device is further that it can make no contribution to active control of the mill with the aim of process optimization.

The object of the invention is to provide a vertical roller mill which, in spite of changing properties of the ground material, ensures that the mill operates as constantly as possible with a uniform and well-prepared grinding bed for grinding in the grinding gap.

This object is achieved by a vertical roller mill with the features of independent claim 1. Advantageous further developments result from the subclaims, the following description and the drawings.

The object of the invention is also to provide a method for the optimized operation of a vertical roller mill.

With regard to the method, the object is achieved by a method for operating a vertical roller mill with the features of patent claim 15.

According to the invention, it is provided that the vertical roller mill has at least one measuring device for measuring forces acting on the installation, a control and regulating device for evaluating measuring signals from the measuring device and for generating an actuating signal for actively adjusting the distance of the compression element from the surface facing the roll of the plate (hereinafter also referred to as “grinding path”) depending on the measurement signals of the measuring device and an adjusting device by means of which the distance of the compression element from the surface of the plate facing the roller can be adjusted depending on the positioning signal of the control and regulating device. The measurement of the forces actually acting on the installation provides real-time information on changing material properties of the regrind, such as changes in the particle size composition, the maximum particle size, the proportion of particularly fine particles, the particle shape, the bulk density, the material moisture, the composition of the feed mixture and the proportion of circulating material in the regrind. A change in the measurement signals of the measuring device can be used to derive how the compression element of the installation has to be regulated in order to reflect the changed material properties reacting the ground material in such a way that an optimized mill operation is achieved with regard to certain operating parameters.

According to the invention, it was recognized that the distance of the compaction element in front of the surface of the plate facing the roller (that is, from the so-called “grinding path”) is a decisive influencing variable for energy savings that can be achieved during operation of the mill. The active height adjustment of the compression element relative to the plate or the grinding track provided according to the invention makes it possible to react to changed process conditions (circulation, particle size, material moisture, wear ...). The measurement of the forces and loads acting on the installation can be achieved, for example, using strain gauges, force measuring devices and piezo force transducers. If necessary, these measuring devices or sensors can be cooled by a fluid. For example, they can be installed in a protected interior of the installation. Attachment to the outside of the mill housing is also conceivable.

According to the invention, the measurement signals of the measurement device are fed to a control and regulating device, which carries out an evaluation of the measurement signals and generates an actuating signal for the active adjustment of the distance of the compression element from the surface of the plate (i.e. the grinding path) facing the roll depending on the measurement signals of the measurement device . For example, the distance between the compression element and the grinding track is reduced via the control signal and at the same time it is ensured that the forces acting on the installation do not exceed a predetermined load limit. Depending on other measurement signals, e.g. Strain or acceleration sensors for monitoring the general machine load, the power consumption of the grinding system for evaluating the energy consumption and the height of the grinding bed for evaluating the size reduction, a model-based setpoint is generated and the control signal is thus actively adjusted.

The control signal generated by the control and regulating device is fed to an actuating device. The actuating device adjusts the distance of the compression element from the surface of the plate (ie the grinding path) facing the roller as a function of the actuating signal of the control and regulating device. The actuating device can be designed differently, depending on how the installation or the compression element is designed and which actuating movement is to be carried out in order to change the distance of the compression element from the grinding track. For example, translatory movements or rotary movements can be used to carry out the desired actuating movement of the compression element. Different embodiments of the installation and of the compression element according to the invention are described below, for which appropriately adapted adjusting devices are then also provided.

With regard to the method according to the invention for operating a vertical roller mill, it is provided that the distance of the compacting element from the surface of the plate (ie the grinding path) facing the roller is regulated in such a way that an operating parameter relevant to the operation of the mill assumes an optimized value. The measurement according to the invention of the forces and loads acting on the installation is a prerequisite for being able to actively adjust the distance between the installation and the grinding track. It can be assumed that the deeper the compression element protrudes into the regrind fed to the grinding gap, the higher the forces and loads that occur. At the same time, however, there will also be more material compression or material ventilation, which will enable more efficient grinding with lower energy consumption and possibly higher throughputs (i.e. higher production volumes). It is to be expected that there is an optimum for the height adjustment of the compaction element (ie the adjustment of the distance of the compaction element from the grinding track) because, for example, an insufficient grinding bed height (ie an excessive compaction of the material to be ground) leads to uneven running (increased vibrations) the mill and thus increasing machine loads.

The machine loads occurring in the mill (vibrations, accelerations, strains, torques) are generally recorded. These measured machine loads of the mill can be used in conjunction with the height adjustment of the installation or of the compression element for the new control concept of the mill according to the invention. In connection with existing process signals that describe the machine load, the installation according to the invention enables a new control concept or an expansion of existing control concepts for vertical roller mills, whereby the grinding bed is actively prepared and the grinding process is improved in terms of throughput, energy and water consumption.

For example, in a possible control concept according to the invention, the force measurement on the installation can be used to reduce the distance between the compression element and the grinding track until a significant reduction in the power consumption at the mill drive has been achieved. The specific energy consumption (ie the drive power based on the Product quantity) of the mill can be minimized. At the same time, the forces acting on the installation increase and the machine loads (eg vibrations) increase. The control concept according to the invention now has the task of stabilizing these loads below defined limit values and at the same time minimizing the energy consumption.

Instead of energy consumption, other operating parameters relevant to the operation of the mill are also conceivable, which should assume an optimized value in the context of the control concept according to the invention. For example, the control concept also be aimed at minimizing the amount of process water (i.e. the amount of process water sprayed onto the millbase) or maximizing the amount of mill produced.

According to one embodiment of the invention, the installation has a support arm arranged in front of the grinding gap in the transport direction of the grinding bed, the support arm carrying the compression element. Different arrangements of the compression element on the support arm are conceivable. For example, the compression element can be arranged such that it can move relative to the support arm, or the compression element can be rigidly connected to the support arm. If the compression element is arranged to be movable relative to the support arm, the adjustment device can be designed such that it effects an adjustment movement of the compression element relative to the support arm, i.e. the support arm can be stationary (e.g. firmly connected to the mill housing), and only the compression element carries out the adjustment movement in order to change its distance from the grinding track. If the compression element is rigidly connected to the support arm (for example welded, screwed or riveted to the support arm), the actuating device can be designed such that the entire support arm together with the compression element is adjusted relative to the grinding path, so that the distance of the compression element is thereby changed changed by the grinding track. In both cases, the actuating devices can be arranged outside the mill housing so that they are not affected by the rough operating conditions in the interior of the mill.

According to one embodiment of the invention, the support arm has a hollow interior, sensors of the measuring device for measuring forces acting on the installation being arranged in the hollow interior. As a result, the sensors are protected against influences from the interior of the mill (e.g. due to dust, mechanical stress from the regrind, process water, etc.), which significantly reduces the risk of malfunctions or measurement inaccuracies of the sensors. The sensors for the measuring device can e.g. be designed as strain gauges, force measuring devices or piezo force transducers. Through the hollow interior of the support arm, connection and signal cables can be routed to the sensors from outside the mill housing. Likewise, the cables required for transmitting the measured values can be routed easily and wear-resistant from the sensors to the outside to a control and regulating device arranged outside the mill housing.

In addition, other sensors can be installed in the cavity of the support arm, which have other tasks than the measurement of the forces acting on the installation. For example, sensors for metal detection can be arranged in the hollow interior of the support arm with which metallic foreign bodies in the regrind, e.g. Nuts, bolts, excavator teeth can be detected. If foreign objects of this type are detected in good time, the grinding system can be shut down in a targeted manner and thus prevented from being damaged. This contributes to an increase in plant availability and a reduction in downtime of the grinding plant. In addition, sensors can be arranged in the hollow interior of the support arm, with which sensors the state of wear of the roller or damage to the roller surface can be detected. Such sensors can e.g. be designed as ultrasonic sensors with which the surface of the roller to which the support arm is assigned is scanned.

In addition to measuring sensors, the water injection nozzles with which the process water is sprayed onto the material in front of the grinding gap can also be arranged in the hollow interior of the support arm. The supply lines for the process water to the nozzles can then also be laid in the hollow interior of the support arm. Then the water jet has to be passed through the wall of the hollow support arm, e.g. by inserting the spray nozzles into openings or bores in the support arm wall (e.g. screwed in). In this way, the water pipes and the nozzles for the process water are arranged protected from influences from the interior of the mill.

According to one embodiment of the invention, the compression element is designed as a compression plate which is arranged to be movable relative to the support arm, the actuating device being designed as a drive by means of which the position of the compression plate can be adjusted relative to the support arm. In this embodiment, a further element, which can be arranged in a protected manner in the hollow interior of the support arm, is an adjustment gear with which the compression element can be moved relative to the support arm in order to carry out the active adjustment movement according to the invention. This can be done through the hollow interior of the Support arms extend, for example, a drive shaft, on which pinions are attached, which interact with toothings, which in turn are attached to the compression element. However, other configurations of the adjusting mechanism for adjusting the compression element are also conceivable. The drive motor for driving the adjustment gear can be arranged outside the support arm and also outside the interior of the mill. For example, the drive motor can be arranged on the outside of the housing wall of the mill.

According to one embodiment of the invention, the adjusting device has a drive unit with which the support arm can be moved relative to the plate in such a way that the distance of a central axis of the support arm to the surface of the plate facing the roller (i.e. to the grinding path) changes. In this embodiment, mobility of the compression element relative to the support arm can be dispensed with. For example, the compression element can be designed as a compression plate which is rigidly connected to the support arm. A particularly robust, rigid connection between the support arm and the compression plate is obtained when the compression plate is welded to the support arm. The change in the distance of the compaction element from the grinding path then takes place in that the distance of the support arm together with the compaction element is changed. For this purpose, the drive unit can be arranged on the outside of the housing wall of the mill. The drive unit can e.g. have a mechanical spindle drive with which the support arm is adjusted relative to the housing wall and the plate of the mill. Alternatively, a hydraulic system for adjusting the support arm can also be provided.

According to one embodiment of the invention, the support arm is designed as a rotatably mounted shaft and the compression element as a compression tube, the shaft being arranged eccentrically in the compression tube and connected to it in a rotationally fixed manner, the distance of an outer circumferential surface of the compression tube being turned by means of the adjusting device can be adjusted from the surface of the plate (ie the grinding track) facing the roller. Due to the eccentric arrangement of the shaft in the compression tube, i.e. due to the distance between the central axis of the shaft from the central axis of the compression tube, rotation of the shaft leads to a change in the distance between the outer circumferential surface of the compression tube and the grinding path arranged on the surface of the plate facing the roller. In this embodiment of the invention, the movement of the compression element causing the adjustment is therefore a rotary movement, namely the rotation of the shaft on which the compression tube is mounted eccentrically. In this embodiment too, a rotary drive transmitting the rotational movement to the shaft can be arranged on the outside of the housing wall of the mill.

According to one embodiment of the invention, the compression element is designed as a one-piece compression plate. The compression plate extends in one plane, this plane enclosing an angle of less than 90 ° with a reference plane which is perpendicular to the surface of the plate and in which a central longitudinal axis of the support arm extends. This angle can be used to influence which portion of the regrind transported to the side is transported away. The compaction plate can additionally be arranged tilted by a further angle towards the support arm or away from the support arm.

According to one embodiment of the invention, the compression element is designed as a compression plate, the compression plate being divided into at least two parts in its direction of extension transverse to the grinding bed, the adjacent parts of the connecting plate extending in different planes, the planes being at an angle of less than 180 ° lock in. The tip of the angle points away from the roll, i.e. against the transport direction of the regrind.

According to one embodiment of the invention, the individual parts of the compression plate have different lengths in their direction of extension transverse to the grinding bed.

The material flow of the material to be ground in the direction of the grinding gap is influenced by the choice of the size of the angle which two mutually adjacent parts of the compression plate enclose with one another and / or by the choice of the length of the respective part of the compression plate. The ground material is pre-compressed and deaerated by the compression plate. Depending on the choice of the angle, the regrind can, for example, be specifically retained on the one hand and more pre-compressed, or a larger proportion of the regrind can, on the other hand, preferably directed radially outwards in the direction of the nozzle ring, especially if large material flows are to be processed, so that this partial flow is known as external regrind circulation (short: external circulation) is fed. A combination of different angles of attack along the length of the compaction plate makes it possible, for example, to guide the regrind directly into the nozzle ring near the storage ring, while the angle in the area of the grinding path is selected so that an ideal pre-seal is achieved and large particles are incorporated into the grinding bed become. The angle of attack of the compaction plate or parts of the compaction plate can be designed and optimized depending on the regrind (e.g. cement, blastfurnace slag, raw material, ...). The shape of the Compaction plate can be adapted to the grinding gap or the grinding path contour.

According to one embodiment of the invention, the angle which the planes, in which the parts of the compression plate extend, enclose with one another, is between 90 ° and 180 °, the planes additionally being tilted by an angle toward or away from the support arm. The choice of this tilt angle can also influence the material flow or the formation of the grinding bed in a targeted manner by the material being accumulated less or more by the tilted compression plate.

According to one embodiment of the invention, an injection device is provided with which a liquid such as e.g. Water (also referred to as “process water”) can be sprayed onto the grinding bed in an area between the installation and the grinding gap or, viewed in the transport direction of the regrind, can be sprayed onto the regrind in an area before installation. In the area between the installation and the grinding roller, the inventive design of the installation opens up new possibilities for arranging the water injection or for completely integrating the water injection into the installation. Because the grinding bed is pre-compacted and has a more uniform height across the width of the grinding path, both the amount of water and the vibration level of the grinding system can be reduced by the more targeted introduction of water. There is also the option of injecting water into the area before installation, as seen in the regrind transport direction, and introducing it into the deeper layers of the milling bed due to the plowing action of the compaction element, which can result in further stabilization of the milling bed.

According to one embodiment of the invention, sensors are provided with which the rollers with regard to the state of wear and damage such as e.g. Material breakouts are monitored or with which undesired foreign objects in the regrind can be detected before they reach the grinding gap. If a foreign body is detected, the grinding system can be shut down in a targeted manner and protected from damage. In this way, downtimes of the mill can be reduced and the service life of the mill can be extended.

A long service life of the installation can be achieved by constructive measures as well as by a suitable choice of material or armoring of the compression element and possibly also of the support arm.

• 1 eine Ausführungsform der Erfindung in Seitenansicht von einem Betrachtungspunkt innerhalb des Mühlengehäuses aus gesehen, mit einem als Verdichtungsplatte ausgebildeten Verdichtungselement, wobei die Verdichtungsplatte relativ zu dem Tragarm bewegbar ist;
• 2 eine Draufsicht einer gegenüber der Ausführungsform gemäß 1 leicht abgewandelten Ausführungsform, wobei die Draufsicht auch die außerhalb des Mühlengehäuses angeordneten Komponenten zeigt;
• 3 eine gegenüber den 1 und 2 andere Ausführungsform der Erfindung;
• 4 eine sowohl gegenüber den 1 und 2 als auch gegenüber 3 andere Ausführungsform der Erfindung;
• 5 eine erste Ausführungsform der Verdichtungsplatte;
• 6 eine zweite Ausführungsform der Verdichtungsplatte;
• 7 eine dritte Ausführungsform der Verdichtungsplatte;
• 8 eine vierte Ausführungsform der Verdichtungsplatte.

The invention is explained in more detail below with reference to the figures. They each show schematically

• 1 an embodiment of the invention in side view seen from a viewing point within the mill housing, with a compression element designed as a compression plate, wherein the compression plate is movable relative to the support arm;
• 2nd a plan view of a compared to the embodiment 1 slightly modified embodiment, the plan view also showing the components arranged outside the mill housing;
• 3rd one versus the 1 and 2nd another embodiment of the invention;
• 4th one against both 1 and 2nd as well as opposite 3rd another embodiment of the invention;
• 5 a first embodiment of the compression plate;
• 6 a second embodiment of the compression plate;
• 7 a third embodiment of the compression plate;
• 8th a fourth embodiment of the compression plate.

1 shows the part according to the invention of a vertical roller mill, which is otherwise not shown for reasons of better clarity. Only one grinding roller is shown 3rd that with a surface 8th of the plate 1 a grinding gap 4th trains. Over the circumference of the grinding plate 1 can distribute several, for example three or four roles 3rd be arranged. On the plate 1 is regrind from the outside via a feed device, not shown 2nd upset. The rotation of the plate transports the regrind 2nd towards the grinding gap 4th .

In the transport direction of the regrind 2nd seen in front of the grinding gap 4th is an installation 6 arranged. The installation 6 has a support arm 12 on, which has a rectangular cross section in the illustrated embodiment and a hollow interior 13 having. The support arm 12 carries a compression element 7 that as a compression plate 7a is trained. In the illustrated embodiment, the compression plate 7a formed in one piece, ie it consists, for example, of a one-piece sheet metal element. Alternatively, the compression plate could 7a in their direction of extension transverse to the grinding gap 4th also consist of several parts (eg several individual sheet metal elements). The compression element 7 or the compression plate 7a is relative to the support arm 12 arranged movably. This is through the double arrow 30th indicated. The double arrow 30th indicates that the compression plate 7a in the direction of the double arrow on the plate 1 can be moved to or away from the plate 1. This will make the distance between the bottom edge of the compression plate 7a and the role 3rd facing surface 8th of the plate 1 changed. To the compression plate 7a relative to the support arm 12 in the directions of the double arrow 30th to be able to move is in the interior 13 of the hollow support arm 12 an adjusting gear arranged, which comprises a driven adjusting element such as a shaft on which, for example, drive pinions are arranged, for example with a toothing of the compression plate 7a interact and an adjustment of the compression plate 7a cause.

The regrind 2nd is by the rotation of the plate 1 against the compression plate 7a transported. The compression plate 7a exerts a compaction force on the regrind 2nd , which compresses and deaerates the regrind. At the same time, it becomes a grinding bed 5 generated with an almost uniform bed height. The meal bed 5 is by the rotation of the plate 1 continue towards the grinding gap 4th transported. In the grinding gap 4th becomes the regrind 2nd crushed and ground. The degree of compaction of the grinding bed 4th before moving into the grinding gap 4th and the height of the grinding bed 4th before the grinding gap 4th have a direct impact on the energy consumption of the mill. Opposing effects were found within the scope of the invention. On the one hand, it was found that pre-compression and deaeration of the regrind 2nd as well as a reduction in the height of the grinding bed 5 leads to a reduction in power consumption at the mill drive (positive effect). On the other hand, it was found that simultaneously with increasing pre-compression and deaeration of the grinding bed 4th the forces acting on the installation or the compression plate and the support arm increase and the machine loads in the mill (for example the vibrations) increase (negative effects).

According to the invention, it was recognized that by actively controlling or regulating the distance of the compression element 7 / the compression plate 7a An optimized control or regulation of the entire vertical roller mill is possible if the on installation 6 , ie in the embodiment according to 1 on the compression plate 7a and the support arm 12 acting forces are measured and the position of the compression element 7 relative to the plate 1 is controlled or regulated so that the installation 6 forces and the machine loads (e.g. vibrations), which are measured by other sensors in the mill, remain below predefinable limit values and at the same time a minimized energy consumption of the mill is achieved.

To the on the installation 6 To be able to measure acting forces is, according to the invention, a measuring device 9 provided the sensors 14 for measuring the forces includes. In 1 are the sensors, which are designed, for example, as strain gauges, force measuring devices or piezo force transducers 14 in the interior 13 of the hollow support arm 14 arranged and thus protected from the harsh influences from the mill interior during operation (e.g. dust, splash water, stone chips, etc.). The cables and wires required for the power supply and signal transmission can also be protected by the interior 13 be relocated.

In addition to the sensors for measuring the installation 6 forces are in the interior 13 of the support arm 12 also injectors 31 arranged over the process water on the regrind 2nd can be sprayed on. In the in 1 illustrated embodiment are the nozzles 31 on the area between installation 6 and the grinding gap 4th aligned. The injectors 31 can alternatively also be positioned at other points, for example at the point of the regrind 2nd facing bottom of the support arm 12 or on the compression plate 7a . To get a better overview, the alternative positions for the injection nozzles are in 1

In the interior 13 of the support arm 12 is also a sensor 32 arranged for metal detection, with the metallic foreign body in the regrind 2nd can be detected. With this sensor 32 For example, screws, nuts, broken excavator teeth or other metallic foreign bodies in the regrind 2nd be discovered before entering the grinding gap 4th get there and damage to the grinding roller 3rd being able to lead.

Another sensor 26 that is protected in the interior 13 of the support arm 12 is arranged as an ultrasonic sensor for scanning the surface of the roll 3rd educated. With this sensor 26 can thus the state of wear of the role 3rd determined and damage such as breakouts from the roll surface are determined.

In 2nd is a top view of one opposite that in FIG 1 embodiment shown slightly modified embodiment. A sensor 14 for measuring the on installation 6 forces are in the interior 13 of the support arm 12 arranged. In 2nd further alternative positions for the arrangement of the force sensors are also shown. So are with the reference numerals 14 ' and 14 " marked two alternative positions in which the force measuring sensors of the measuring device 9 can be arranged. In the 2nd positions shown 14 ' and 14 " are outside the mill housing 21st and are therefore the harsh influences the grinding process inside the mill housing 21st withdrawn.

Furthermore, the engine 33 to adjust the compression plate 7a relative to the support arm 12 outside of the housing 21st arranged the mill. The motor 33 drives a gear, not shown in detail, which makes an adjustment movement on the compression plate 7a transmits. The motor 33 is controlled or regulated by an actuating signal which it receives from a control and regulating device 10th receives that also outside the case 21st the mill is arranged. The sensors 14 (or. 14 ' , 14 " ) are connected to the control and regulating device 10th connected. The measured values for the installation are shown on the lines 6 forces from the sensors 14 (or. 14 ' , 14 " ) to the control and regulating device 10th to hand over.

In addition, the control and regulating device 10th also measurement signals from others inside or outside the housing 21st provided sensors received, for example from sensors that measure the machine load (eg vibrations) in the grinding system (not shown). At the same time, the control and regulating device 10th the power consumption of the mill drive are also transmitted. With this information, the regulation of the vertical roller mill already described above can be implemented with the aim of minimizing energy consumption with machine loads remaining below a predetermined limit value.

In the in 2nd illustrated embodiment are within the interior 13 of the support arm 12 three sensors spaced apart in the longitudinal direction of the support arm 26 arranged, which are designed as ultrasonic sensors and which serve the wear state of the roller 3rd to determine and damage to the roll such as breakouts in the area of the grinding surface of the roll 3rd to detect.

3rd shows one against the 1 and 2nd another embodiment of the invention in a front view, both inside and outside the housing 21st the mill shows arranged system components. The compression element 7 is as a compression plate 7a educated. The compression plate 7a is rigid with the support arm 12 connected, for example to the support arm 12 welded, screwed to this or riveted to it. In the embodiment of the invention according to 3rd the entire support arm 12 together with the compression plate rigidly attached to it 7a adjusted to the distance between the compression plate 7a and the role 3rd facing surface 8th of the plate 1 to change. The adjustment movement of the support arm 12 along the double arrow 39 is to be effected on the outside of the housing 21st an actuator for the mill 11 arranged. This actuator 11 can be designed, for example, as a spindle drive or as a hydraulic system, for example with an adjustable hydraulic ram. In the actuator 11 is on the outside of the housing 21st a sensor of the mill 14 for measuring the on installation 6 acting forces arranged. The sensor 14 is connected via lines, not shown, to a control and regulating device, also not shown, analogous to the description of 2nd .

In the exemplary embodiment according to 3rd is the compression plate 7a in two parts 34 , 35 divided up. The two parts 34 , 35 point in their direction of extension transverse to the roll 3rd each have a different length. The two parts 34 , 35 are angled towards each other like this in 5 is shown in more detail. Because of for 3rd chosen perspective is the angle between the parts 34 , 35 in 3rd not recognizable. The longer part 35 the compression plate 7a is employed so that it grinds 2nd radially inwards towards the center of the plate 1 derives (indicated by the arrow pointing to the right 37 . The shorter part 34 is on the other hand parked so that it is the regrind 2nd radially outwards over the edge 36 of the plate 1 derives (indicated by the arrow pointing to the left 38 ), so that the regrind derived in this way reaches the regrind circulation.

In an embodiment, not shown, the compression plate 7a also be formed in one piece. Then the angle of incidence can only be used to discharge the regrind in one direction (either towards the center of the plate or radially outwards over the edge 36 of the plate 1 ) to be influenced.

4th shows one against the 1 to 3rd yet another embodiment of the invention. The compression element 7 is here as a compression pipe 19th educated. The compression pipe 19th is about a wave 18th rotatably mounted. The wave 18th is with the compression pipe 19th non-rotatably connected. The wave 18th is eccentric to the central axis 41 of the compression pipe 19th arranged. By twisting the shaft 18th by means of an in 4th Adjustment device, not shown 11 is the distance between the outer surface of the compression tube 19th to that of the role 3rd facing surface 8th of the plate 1 changed. In the 4th Measuring device, not shown 9 and the control and regulating device, also not shown 10th can be analogous to the embodiments according to the 1 to 3rd be arranged and trained. Instead of being arranged in the interior of a hollow support arm, the sensors and / or the components of the adjustment device can be located in the interior of the compression tube 19th be arranged.

5 shows a compression plate 7a that in two parts 22 , 23 is divided. The two parts 22 , 23 are in levels E ₁ and E ₂ arranged and close an angle α between themselves. The top of the angle shows when the compression plate is installed 7a against the transport direction of the regrind 2nd , ie the tip of the angle points from the support arm 12 path. The two-part compression plate 7a thus acts like a plow on the regrind when installed 2nd a. The adjacent parts 22 , 23 the connecting plate 7a extend in different levels E ₁ , E ₂ , the levels E ₁ , E ₂ an angle with each other α Include less than 180 °. In the illustrated embodiment, the angle is α approximately in the range of 130 ° to 160 °. By choosing the size of the angle α can the jamming effect of the compression plate 7a be influenced on the regrind. It can also be used to influence how much regrind 2nd is derived radially inwards or radially outwards per unit of time.

6 shows the same distribution of the compression plate 7a in two parts 22 , 23 how 5 , however, the parts 22 , 23 through an angle β towards the support arm 12 are tilted. By tilting the compression plate 7a a wedge-shaped material feed occurs. The material to be ground becomes through the rotation of the grinding track 2nd , compared to the previously vertically arranged compression plate 7a , more vented and compressed in this tilted version.

7 shows a three-part compression plate 7a . The parts 22 and 23 are comparable to those in 5 , with a third part 40 is provided, which is in one level E ₃ lies parallel to a reference plane B, which is perpendicular to the surface 8th of the plate 1 stands and in which there is a central longitudinal axis of the support arm 12 extends. By such a design of the compression plate 7a the result is that the regrind is enriched at a position on the grinding track and compacted more. As a result, depending on the shape of the grinding track and / or the roller geometry, the grinding bed can be targeted 5 be prepared.

8th shows an embodiment of the invention in which the parts 22 , 23 the compression plate 7a through an angle β from the reference plane B or from the support arm 12 are tilted away. This ensures that the regrind 2nd is evened out over the width of the grinding path and at the same time onto the compaction plate 7a acting forces can be reduced. This can be the case with very heavily loaded compaction plates 7a , e.g. B. with very high material circulation, may be necessary, even if the compaction and deaeration of the ground material 2nd this is slightly lower than the other variants.

The preceding to the 5 to 8th described effects of the angle of attack α and the tilt angle β apply analogously in the same way to the embodiments of the invention in which the compression plate 7a is formed in one piece.

In all embodiments of the invention, the tilt angle β are in the range between 0 ° and 40 °, preferably between 5 ° and 30 °.

Reference symbol list

1

Plate

2nd

Regrind

3rd

role

4th

Grinding gap

5

Meal bed

6

Installation

7

Compression element

7a

Compaction plate

8th

surface

9

Measuring device

10th

Control and regulating device

11

Actuator

12

Beam

13

inner space

14

Sensors

15

Drive

16

Drive unit

17th

Central axis

18th

wave

19th

Compression pipe

20th

Lateral surface

21st

casing

22

Part of the compression plate

23

Part of the compression plate

25th

Injector

26

Sensors

30th

Double arrow

31

Injectors

33

engine

34

part

35

part

36

edge

37

arrow

38

arrow

39

Double arrow

40

part

41

Central axis

E1

level

E2

level

α, β,

angle

Claims (19)

Vertical roller mill with a driven plate (1) rotatably mounted about an axis of rotation for transporting regrind (2), a feeding device for feeding the regrind (2) onto the plate (1), and at least one roller (3), the Roll (3) with the plate (1) forms a grinding gap (4), the ground material (2) on the plate (1) forming a grinding bed (5) which the grinding gap (4) by rotating the plate (1) can be supplied, an installation (6) for venting and compressing the grinding bed (5) and for equalizing a height of the grinding bed (5) fed to the grinding gap (4) is provided in front of the grinding gap (4) in the transport direction of the grinding bed (5), wherein the installation (6) has a compression element (7), the distance of which from the surface (8) of the plate (1) facing the roller (3) is variable, characterized in that the vertical roller mill has - at least one measuring device (9 ) for measuring forces acting on the installation (6), - a Control and regulating device (10) for evaluating measurement signals from the measuring device (9) and for generating an actuating signal for actively adjusting the distance of the compression element (7) from the surface (8) of the plate (1) facing the roller (3) as a function of it of the measuring signals of the measuring device (9) - an adjusting device (11), by means of which the distance of the compression element (7) from the surface (8) of the plate (1) facing the roller (3) as a function of the control signal of the control and Control device (10) is adjustable. Vertical roller mill after Claim 1 , characterized in that the installation (6) has a support arm (12) arranged in front of the grinding gap (4) in the transport direction of the grinding bed (5), the support arm (12) carrying the compression element (7). Vertical roller mill after Claim 2 characterized in that the support arm (12) has a hollow interior (13), sensors (14) of the measuring device (9) for measuring forces acting on the installation (6) being arranged in the hollow interior (13). Vertical roller mill after Claim 1 or 2nd , characterized in that the measuring device (9) has at least one sensor (14) for measuring forces acting on the installation (6), the sensor (14) being arranged on a housing (21) of the mill. Vertical roller mill according to one of the Claims 2 to 4th , characterized in that the compression element (7) is designed as a compression plate (7a) which is movably arranged relative to the support arm (12), the actuating device (9) being designed as a drive (15) through which the position of the compression plate (7) is adjustable relative to the support arm (12). Vertical roller mill according to one of the Claims 2 to 4th , characterized in that the adjusting device (11) has a drive unit (16) with which the support arm (12) can be moved relative to the plate (1) in such a way that the distance from a central axis (17) of the support arm (12) increases the surface (8) of the plate (1) facing the roller (3) is changed. Vertical roller mill after Claim 6 , characterized in that the compression element (7) is firmly connected to the support arm (12), in particular welded. Vertical roller mill according to one of the Claims 2 to 4th , characterized in that the support arm (12) is designed as a rotatably mounted shaft (18) and the compression element (7) as a compression tube (19), the shaft (18) being arranged eccentrically in the compression tube (19) and connected to it in a rotationally fixed manner whereby the distance between an outer circumferential surface (20) of the compression tube (19) and the surface (8) of the plate (1) facing the roller (3) can be adjusted by rotating the shaft (18) by means of the adjusting device (11). Vertical roller mill after Claim 8 , characterized in that the actuating device (11) is designed as a rotary drive. Vertical roller mill according to one of the Claims 5 to 9 , characterized in that the actuating device (11) is arranged outside a housing (21) of the mill. Vertical roller mill according to one of the Claims 2 to 7 or 10th , characterized in that the compression element (7) is designed as a one-piece compression plate (7a). Vertical roller mill after Claim 11 , characterized in that the compression plate (7a) extends in a plane (E ₁ ), the plane (E ₁ ) with a reference plane (B) perpendicular to the surface (8) of the plate (1), in which a central longitudinal axis of the support arm (12) extends, an angle (a) less than 90 °. Vertical roller mill after Claim 10 or 11 , characterized in that the compression plate (7a) is tilted by an angle (β) to the support arm (12) or away from the support arm (12). Vertical roller mill according to one of the Claims 2 to 7 or 10th , characterized in that the compression element (7) is designed as a compression plate (7a), the compression plate (7a) being divided in its direction of extension transversely to the grinding bed (5) into at least two parts (22, 23), the parts adjacent to one another (22, 23) of the connecting plate (7a) extend in different planes (E ₁ , E ₂ ), the planes (E ₁ , E ₂ ) enclosing an angle (a) of less than 180 ° with one another. Vertical roller mill after Claim 14 , characterized in that the individual parts (22, 23) of the compression plate (7a) have different lengths in their direction of extension transverse to the grinding bed (5). Vertical roller mill after Claim 14 or 15 , characterized in that the angle (α), which the planes (E ₁ , E ₂ ) enclose with one another, is between 90 ° and 180 °, the planes (E ₁ , E ₂ ) additionally being at an angle (β) to the Support arm (12) or tilted away from the support arm (12). Vertical roller mill according to one of the preceding claims, characterized in that an injection device (25) is provided, by means of which a liquid such as water is sprayed onto the grinding bed (5) in a region between the installation (6) and the grinding gap (4) or seen in the transport direction of the regrind (2) in an area before installation (6) onto the regrind (2). Vertical roller mill according to one of the preceding claims, characterized in that sensors (26) are provided with which the rollers (3) are monitored with regard to the state of wear and damage such as material breakouts or with which undesired foreign objects in the regrind (2) can be detected, before they get into the grinding gap (4). Method for operating a vertical roller mill according to one of the Claims 1 to 18th , characterized in that the distance of the compression element (7) from the surface (8) of the plate (1) facing the roller (3) is regulated in such a way that an operating parameter relevant to the operation of the mill assumes an optimized value.

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