METHOD FOR LOAD-DEPARATE OPERATION OF A MATERIAL SHREDDING PLANT

Description

[0001] The invention relates to a method for controlling the feed to a crusher of a material crushing plant driven by a crusher drive via transmission elements, wherein material to be crushed, in particular rock material to be crushed, is fed to the crusher, wherein a fill level of the crusher, preferably at a crusher inlet, is determined by means of a fill level sensor and wherein the volume flow of material to be crushed supplied to the crusher is set and / or controlled depending on the determined fill level.

[0002] The invention also relates to a control unit for operating such a material shredding plant.

[0003] Material crushing plants of the type described above are used for crushing rock materials, such as natural stone, concrete, bricks, or recycled materials. The material to be crushed is fed into a feed unit of the material crushing plant, for example, in the form of a hopper, and conveyed to a crusher via transport devices, such as a vibrating feeder or a belt conveyor. A pre-screening unit can be installed upstream of the crusher to remove fines or medium-sized particles that already have the appropriate particle size. The crusher itself can be designed as a jaw crusher, an impact crusher, or a cone crusher. In a jaw crusher, two jaws arranged at an angle to each other form a wedge-shaped chamber into which the material to be crushed is fed.While one jaw crusher is stationary, the opposite jaw crusher can be moved by means of an eccentric mechanism. This results in an elliptical movement of the moving jaw crusher, which crushes the material and guides it downwards in the shaft to a crushing gap. The width of the crushing gap, and thus the particle size of the crushed material discharged from the wedge-shaped shaft through the crushing gap, can be adjusted using a gap adjustment mechanism. The fill level of the material to be crushed in the shaft can be measured using a level sensor, such as an ultrasonic sensor. The flow rate of the material fed to the crusher via the conveying system can be adjusted by controlling the conveying system accordingly, depending on the measured fill level.

[0004] During the crushing process, the crusher is subjected to high mechanical stresses. These result, among other things, from the feed size, particle size distribution, and compressive strength of the material being fed, as well as the desired reduction ratio and the fill level of the material to be crushed within the crusher's crushing chamber. Incorrect operation of the material crushing plant, particularly with excessively large feed particle sizes and reduction ratios, can lead to overloading of the crusher. This can damage or cause premature wear of various highly stressed components of the crusher, the crusher drive, or the transmission elements.

[0005] WO 2016 / 162598 discloses a method and a crusher that detect crusher bridging. In this cone crusher, the cone shaft is rotatably mounted in an axial bearing. The axial bearing is supported by arms extending radially from the outer walls of the cone crusher. Crushing can occur if material becomes trapped between the cone and an arm, causing the cone to lift and potentially damaging the crusher. To detect such bridging to a support arm, the load on the support is determined and evaluated. This can be done by measuring the pressure in a hydraulic cylinder of a hydraulic actuator used for vertical adjustment of the cone. The power consumption of the crusher's drive can also be considered in the evaluation.Also described is the possibility of measuring and evaluating mechanical stresses introduced into the arms of the support structure, for example, using strain gauges. The measurement can be taken directly on the arms, but also on adjacent structural components that are connected to the arms. If bridging of the crusher is detected, it is suggested that the crusher's loading be reduced or interrupted.

[0006] From WO 2008 / 153464 A1, a method for controlling a crusher is known to which rock is fed via a feeding device. The rock is supplied via a conveyor belt driven by a hydraulic motor. The fill level in a feed hopper is measured by two level sensors. A deviation is calculated by comparing the current fill level with a target value. An output variable determined by a controller based on this deviation is fed to the hydraulic motor of the conveyor belt to regulate the material feed.

[0007] Further methods for regulating material supply are known from US 4 909 449 A, US 4 804 148 A, DE 18 09 339 A1, DE 11 64 216 B and WO 2007 / 051890 A1.

[0008] The object of the invention is to provide a method that reliably prevents overloading of a crusher in a material shredding plant. A further object of the invention is to provide a control device for carrying out such a method.

[0009] The object of the invention relating to the method is achieved by directly or indirectly determining the mechanical load on the crusher or a characteristic parameter dependent on the mechanical load of the crusher, and by adjusting the fill level of the crusher as a function of the determined mechanical load or the characteristic parameter dependent thereon. Different material properties, such as different feed sizes, particle size distributions, compressive strengths, and different comminution ratios, lead to different loads on the crusher at a given fill level.

[0010] According to the invention, the mechanical load on the crusher, or a parameter dependent on the mechanical load of the crusher, is determined. Depending on the mechanical load of the crusher, a fill level is specified at which overloading of the crusher is reliably avoided while maximizing material throughput. This is preferably achieved by controlling the material feed components, for example, a vibrating feeder, based on the fill level of the crusher measured by the fill level sensor.

[0011] A reliable determination of the existing mechanical load on the crusher can be achieved by measuring the mechanical load and / or the movement behavior of at least one component of the crusher, the transmission elements, and / or the crusher drive as a parameter dependent on the mechanical load of the crusher, and / or by measuring an operating state of the crusher drive as a parameter dependent on the mechanical load of the crusher. The measurement of the mechanical load of the at least one component is preferably carried out on a mechanically heavily loaded component of the crusher, the transmission elements, or the crusher drive. If the fill level adjustment according to the invention ensures that the mechanically heavily loaded component is not overloaded, it can be assumed that the other components of the crusher are also operating within their permissible load range.For the purposes of the present invention, transmission elements are understood to be all components which are intended for the transmission of torque and / or power from the crusher drive to the crusher.

[0012] According to a particularly preferred embodiment of the invention, the elastic strain of at least one component of the crusher, the transmission elements, and / or the crusher drive can be determined to ascertain its mechanical load. The fill level of the crusher is then adjusted based on this determined elastic strain or a value derived therefrom. The elastic strain of the at least one component is directly dependent on the mechanical load on the component and thus on the mechanical load on the crusher. By monitoring this strain, the fill level of the crusher can be adjusted to reliably prevent overloading.

[0013] A simple and reliable measurement of the elastic strain of at least one component can be achieved by determining the elastic strain with at least one sensor, for example, a strain gauge. Advantageously, the at least one strain gauge can be easily attached to the component being monitored.

[0014] Advantageously, the system can be designed to determine the mechanical stress of at least one component of the crusher, transmission elements, or crusher drive from its elastic strain, and to adjust the crusher's fill level based on this mechanical stress. The determined mechanical stress can then be compared to the permissible stresses of the material used. The crusher's fill level can then be regulated to ensure that the permissible stresses of the component's material are not exceeded, advantageously taking a safety factor into account.

[0015] According to one possible embodiment of the invention, the acceleration, preferably with an acceleration sensor, and / or rotational speed and / or change in rotational speed, preferably with a rotational speed sensor, can be determined to ascertain the movement behavior of at least one component of the crusher, the transmission elements, and / or the crusher drive. When the load on the crusher changes, the movement behavior in the drive train changes. This can be a continuous change in movement behavior, for example, a change in rotational speed, or a short-term change, for example, when the power of the crusher drive is readjusted due to a change in movement behavior and a predetermined target rotational speed is restored.A change in the movement behavior of at least one component of the crusher, the transmission elements and / or the crusher drive, caused by a change in the load on the crusher, can be used to infer the load on the crusher.

[0016] Typically, the crusher drive is designed to operate at an adjustable nominal speed. When the crusher load changes, the nominal speed is adjusted by a corresponding power adjustment of the crusher drive. The power required by the crusher drive and the associated operating parameters are therefore dependent on the current crusher load. If the power of the crusher drive is not adjusted in response to changing crusher loads, this will result in a change in the crusher drive's speed. Therefore, the operating state of the crusher drive may be determined by power output, torque, energy consumption, fuel consumption, and / or the drive's speed.These parameters are directly related to the load to be applied by the crusher and thus to the mechanical stress on the crusher, so that if they are known, a suitable fill level of the crusher can be set.

[0017] Overloading of the crusher can be avoided by reducing the fill level of the crusher when the mechanical load on the crusher or a parameter directly dependent on the mechanical load of the crusher exceeds a predetermined upper limit, or when a parameter inversely dependent on the mechanical load of the crusher falls below a predetermined lower threshold, and / or by reducing the fill level of the crusher.The crusher will be reduced if the mechanical load on the crusher, or a parameter directly dependent on the mechanical load, exceeds the specified upper limit with a specified frequency or for a specified duration within a specified initial period Δt 1, or if a parameter directly dependent on the mechanical load of the crusher falls below the specified lower threshold with a specified frequency or for a specified duration within the specified initial period Δt 1. The limit or threshold defines when the permissible load on the crusher is exceeded. If the crusher's fill level is reduced after a single instance of exceeding the limit or falling below the threshold,This allows for a rapid response to excessive crusher load. If the limit value must be exceeded multiple times within the specified initial period Δt 1, or cumulatively over a predetermined duration, to reduce the fill level, the reliability of the crusher load assessment can be increased. The same applies to falling below the threshold value for the parameter inversely dependent on the crusher's mechanical load. Specifying a frequency for exceeding or falling below the limit value is particularly advantageous for jaw crushers, as these are subject to cyclic loading due to the cyclical opening and closing of the movable crushing jaw.

[0018] A high crusher throughput can be achieved by increasing the crusher's fill level if the crusher's mechanical load, or a parameter directly dependent on the crusher's mechanical load, does not exceed a predetermined lower limit over a predetermined second period Δt 2, or if a parameter inversely dependent on the crusher's mechanical load does not fall below a predetermined upper threshold over the predetermined second period Δt 2, and / or by increasing the crusher's fill level.The system is triggered if the mechanical load on the crusher, or a parameter directly dependent on the mechanical load, does not exceed the specified lower limit value more than once with a specified frequency or for a specified duration over the specified second period Δt 2, or if a parameter conversely dependent on the mechanical load of the crusher does not fall below the specified upper threshold value more than once with a specified frequency or for a specified duration over the specified second period. A consistently low mechanical load on the crusher can be demonstrated by consistently falling below the limit value or exceeding the threshold value. Increasing the fill level allows the crusher's throughput to be increased without overloading it. This enables economical operation of the crusher or material shredding plant.

[0019] If it is stipulated that, after a reduction and / or increase in the crusher's fill level, no further determination and / or evaluation of the crusher's mechanical load or the parameter dependent on the crusher's mechanical load, and / or no further adjustment of the crusher's fill level, takes place until a predetermined waiting period Δt blind1, Δt blind2 has elapsed, then sufficient time remains after an initiated change in the fill level for the newly specified fill level to be established. This prevents oscillation of the control loop.

[0020] It can be advantageous to have the crusher's fill level reduced and / or increased by a predetermined absolute amount, or to have it reduced and / or increased by a value relative to the current fill level. Changing the fill level by absolute amounts is easy to implement. The advantage here is that the change in fill level is the same for both reductions and increases, allowing for the consistent setting of specific fill levels optimized for particular tasks. With changes relative to the current fill level, different adjustments can be made. For example, large changes can be made starting from a high fill level, and small changes starting from a low fill level. Of course, applications where the opposite approach is used are also conceivable.This allows for precise adjustment of the fill level, especially at high crushing ratios (small gap width of the crushing nip), which place a high load on the crusher and therefore require a comparatively low fill level. The crushing ratio describes the ratio of the particle size of the feed material at 80% screening to the particle size of the final product at 80% screening.

[0021] This ensures a high throughput of the crusher or material shredding plant even with high crushing levels.

[0022] A simple assessment of the crusher's load, which can easily be implemented in a computer program, can be achieved by defining load categories, each corresponding to low, desired, or excessive load on the crusher. Alternatively, specific mechanical loads on the crusher, or specific values ​​of parameters dependent on the crusher's mechanical load, can be assigned to a load category. The fill level can then be adjusted based on the load category to which the determined loads or parameters are assigned.

[0023] It can be stipulated that the crusher's fill level is reduced if, over a predetermined first period, a specified number of measured crusher loads or values ​​of the load-dependent parameter are assigned to a load category corresponding to excessive load; that the crusher's fill level is increased if, over a predetermined second period, a specified number of measured loads or values ​​of the load-dependent parameter are assigned to a load category corresponding to low load; and that the fill level remains unchanged if the measured loads or the values ​​of the load-dependent parameter are assigned to a desired load category. The crusher's fill level is thus adjusted to the respective load categories depending on the assignment of the measured crusher load or the dependent parameter.

[0024] Crushers typically experience cyclical loading, with periodically recurring maximum loads. These maximum loads must not exceed the crusher's maximum load, at least not permanently. Therefore, it may be necessary to determine the maximum load values ​​of the crusher, or the values ​​of the load-dependent parameter corresponding to these maximum values, when the crusher's load fluctuates periodically. The crusher's fill level may then be adjusted based on these maximum load values ​​or the values ​​of the load-dependent parameter corresponding to these maximum values.

[0025] The problem of the invention relating to the control device is solved by a control device for operating a material crushing plant with a crusher, wherein the control device is designed to carry out at least the following steps: Detection and storage of a mechanical load on the crusher or a parameter dependent on the mechanical load of the crusher, adjustment of the fill level of the crusher depending on the detected mechanical load or the parameter dependent on it. The control unit thus enables the execution of the procedure described above.

[0026] Within the scope of the invention, it is further conceivable to provide a computer program product that can be directly loaded into the internal memory of a digital computer and comprises software code sections with which the steps according to one of claims 1-14 are carried out when the product is running on a computer.

[0027] It is also conceivable to provide a computer program product that is stored in a medium that can be inserted into a computer, comprising computer-readable program means with which a computer can execute the method according to one of claims 1-14.

[0028] The computer programs can be easily implemented in the control unit of the material shredding plant. They can advantageously utilize measurement signals from an existing level sensor connected to the control unit. Furthermore, they can interact with existing control loops that regulate the material feed components based on the level sensor signal. Thus, the process can be cost-effectively integrated into existing material shredding plants through a simple software upgrade.

[0029] The invention will be explained in more detail below with reference to an embodiment illustrated in the drawings. The drawings show: Figure 1, in a side view, partially cut away, shows a material crushing plant with a crusher; Figure 2, in an enlarged perspective view, shows the in Figure 1 The crusher shown in Figure 3 has measured values ​​for a mechanical stress of a component plotted in a stress-time diagram. Figure 1 and 2 The crusher shown and Figure 4 in a simplified representation show a screen output of different load categories.

[0030] Figure 1Figure 1 shows a side view, partially cut away, of a material shredding plant 10 with a crusher 50. The material shredding plant 10 can be designed as a mobile unit with a chassis 11 and a chain drive 13. It has a feed unit 20, optionally a pre-screening unit 30, the crusher 50 and at least one crusher discharge conveyor 40.

[0031] A hopper 21 can be arranged in the area of ​​the feed unit 20. The hopper 21 has hopper walls 22. It directs the fed feed material 70 onto a vibrating feed trough 23.

[0032] The vibrating feed chute 23 conveys the feed material 70 to a double-deck pre-screen 31 of the pre-screening unit 30. The double-deck heavy-duty screen 31 has an upper deck 32 designed as a comparatively coarser screen and a lower deck 34 designed as a comparatively finer screen. It is set into circular vibration by a drive 33. The upper deck 32 separates a fine fraction 71 and a medium fraction 72 from the material 73 to be crushed. The lower deck 34 separates the fine fraction 71 from the medium fraction 72. The fine fraction 71 can optionally be discharged from the material shredding unit 10 or fed to the medium fraction 72 by appropriately positioning a bypass flap. The medium fraction 72 is conveyed via a bypass past the crusher 50 to the crusher discharge conveyor 40. The material 73 to be crushed is fed to the crusher 50 via a crusher inlet at the end of the pre-screening 30.

[0033] The crusher 50 is designed as a jaw crusher. However, it is also conceivable to provide other crushers 50, for example, impact crushers or cone crushers. The crusher 50 has a fixed crushing jaw 51 and a moving crushing jaw 52. These are arranged at an angle to each other, so that a shaft is formed between them that tapers conically towards a crushing gap 56. The moving crushing jaw 52 is driven by an eccentric 54. The eccentric 54 can be connected via a drive shaft 55 to a drive unit 12 of the material crushing plant 10. The drive unit 12 serves as the crusher drive. It can also be used as a drive for the conveying devices, the chain drive, and, if necessary, other moving components of the material crushing plant 10. The eccentric 54 moves the moving crushing jaw 52 in an elliptical motion towards and away from the fixed crushing jaw 51.During such a stroke, the distance between the crushing jaws 51, 52 in the area of ​​the crushing gap 56 also changes. The movement of the moving crushing jaw 52 continuously reduces the material 73 to be crushed along the conical shaft until it reaches a particle size that allows it to exit the shaft through the crushing gap 56. The crushed material 74 falls onto the crusher discharge conveyor 40 and is conveyed further. It may also be provided, for example, that it passes by a magnetic separator 41, which separates metallic magnetic components from the crushed material 74 and discharges them laterally.

[0034] A level sensor 61 is assigned to the crusher 50. The level sensor 61 is in Figure 1The level sensor 61 is shown schematically. It is designed as an ultrasonic sensor in this example. However, other sensor types are also conceivable, such as optical sensors (e.g., a camera system) or mechanical sensors. The level sensor 61 monitors the fill level of the crusher 50 with material 73 to be crushed. It is part of a continuous feed control system for the material crushing plant 10. For this purpose, the material-feeding components of the material crushing plant 10, in particular the vibrating feeder 23 and / or the double-deck pre-screen 31, are controlled according to the signals from the level sensor 61, thereby regulating the volume flow of the material 73 to be crushed that is fed to the crusher 50.

[0035] Figure 2 shows in an enlarged perspective view the in Figure 1The crusher 50 shown. The conical shaft of the crusher 50, which tapers towards the crushing gap 56, is clearly visible between the two crushing jaws 51, 52. The material 73 to be crushed is fed into this shaft via the pre-screening unit 30. The moving crushing jaw 52 is driven by the eccentric 54. For this purpose, the moving crushing jaw 52 is mounted on a movably mounted crushing arm 53, on which the eccentric 54 acts. The crushing arm 53 can be supported towards the crushing gap 56 by a pressure plate 58. The pressure plate 58 is connected to a gap adjustment 57 opposite the crushing arm 53. The width of the crushing gap 56, and thus the particle size of the crushed material 74, can be adjusted using the gap adjustment 57. The in Figure 1 The schematically depicted level sensor 60 is in Figure 2 It is not shown, but it is intended for monitoring the fill level.

[0036] The pressure plate 58 is a component of the crusher 50. It is subjected to high mechanical loads during the operation of the crusher 50. These loads are representative of the load on the crusher 50 as a whole. The load on the crusher 50, and thus on the pressure plate 58, changes cyclically with the movement of the moving crushing jaw 52. The maximum loads occur during a working stroke, when the moving crushing jaw 52 moves towards the stationary crushing jaw 51. These maximum loads cause the greatest wear on the components of the crusher 50. If the maximum loads are too high, this can lead to damage to the crusher 50, the crusher drive, or the transmission elements (e.g., eccentric 54).

[0037] To measure the load on the crusher 50, a strain gauge 60 can be attached, for example, to the pressure plate 58 or to another force-transmitting component connected to the pressure plate 58. The strain gauge 60 measures the elastic strain of the pressure plate 58 or of a force-transmitting component. This is a measure of the mechanical load on the pressure plate 58 and thus also a measure of the mechanical load on the crusher 50. The strain of the pressure plate 58 is a characteristic value that depends on the mechanical load on the crusher 50. According to the invention, the fill level of the crusher 50 is adjusted depending on the specific mechanical load on the crusher 50 or a characteristic value dependent thereon. This is achieved by appropriately controlling one or more of the components that feed the material 73 to be crushed into the crusher 50, depending on the fill level determined by the level sensor 61.

[0038] Figure 3 shows measured values ​​for a mechanical stress of a component of the in the in a stress-time diagram. Figure 1 and 2 The crusher 50 shown. Specifically, maximum stress values ​​84, as they occur in successive strokes of the jaw crusher 50, are plotted against a stress axis 80 and a time axis 81. For clarity and presentation, the maximum stress values ​​are shown at a very low frequency. In practice, significantly more working strokes can be performed per unit of time and evaluated according to the following representation. The maximum stress values ​​84 are shown here using the Figure 2The strain gauges 60 shown are measured on the pressure plate 58. An upper limit 82 and a lower limit 83 for the stresses are indicated by horizontal dotted lines. During the first five strokes, the determined maximum stress values ​​84 lie within the desired range between the upper and lower limits 82, 83. On the sixth stroke, the measured maximum stress value 84 exceeds the upper limit 82. When the maximum stress value 84 is first exceeded, a first period Δt 1 86.1 begins. The first period Δt 1 86.1 is, for example, 2 minutes. It starts at a first time t 1 85.1 and ends at a third time t 3 85.3. If a predetermined number of maximum stress values ​​84 exceed the upper limit 82 within the first period Δt 1 86.1, an overload of the crusher 50 is assumed.In the illustrated embodiment, an overload of the crusher 50 is assumed if, within the first period Δt 1 86.1, three maximum stress values ​​84 exceed the upper limit 82. This occurs at a second time point t 2 85.2. From this second time point t 2 85.2, the fill level of the crusher 50 is reduced. Simultaneously, a first waiting period Δt blind 1 86.2 begins. Within the first waiting period Δt blind 1 86.2, the determined maximum stress values ​​84 are not evaluated and / or the fill level is not readjusted. This provides sufficient time to adjust the fill level of the crusher 50 according to the new specifications. In this case, the first waiting period Δt blind 1 86.2 is two minutes. It ends at a fourth time point t 4 85.4. After the first waiting period Δt blind 1 86.2, the maximum voltage values ​​84 are recorded and evaluated again.If these values ​​lie between the two limit values ​​82 and 83, no further adjustment of the fill level occurs. If the maximum stress values ​​84 fall below the lower limit value 83, as shown in the example at a fifth time point t5 85.5, a second period Δt2 86.3 begins. In this case, the second period Δt2 86.3 lasts one minute. It therefore ends at a sixth time point t6 85.6. If, as in the illustrated embodiment, the measured maximum stress values ​​84 are below the lower limit value 83 within the second period Δt2 86.3, the fill level of the crusher 50 is increased after the second period Δt2 86.3 has elapsed, i.e., at the sixth time point t6 85.6. Here, too, a waiting period (second waiting period Δt2 86.4) begins with the change in the fill level. The second waiting period Δt blind 2 86.4 is two minutes in this case and thus corresponds to the first waiting period Δt blind 1 86.2.It ends at a seventh time point t 7 85.7. Preferably, the duration of the waiting periods Δt blind 1 / 2 86.2, 86.4 is the same. Within the second waiting period Δt blind 2 86.4, the maximum stress values ​​84 are not measured or evaluated and / or the fill level is not adjusted. The second waiting period Δt blind 2 86.4 thus provides sufficient time for the new fill level of the crusher 50 to establish itself. After the second waiting period Δt blind 2 86.4 has elapsed, the maximum stress values ​​84 are monitored again.

[0039] Through the in Figure 3The monitoring of the maximum stress values ​​84 and the corresponding adjustment of the fill level of the crusher 50 when the respective limit values ​​82, 83 are exceeded or fallen below ensure that the maximum stresses, in this case on the pressure plate 58 as a component of the crusher 50, are regulated within a predetermined range. Due to the correlation between the load on the pressure plate 58 and that of the entire crusher 50, its load can also be kept within a permissible range. This prevents overloading of the crusher 50, the crusher drive, and the transmission elements. Simultaneously, a maximum throughput of the crusher 50 is achieved without overloading it.

[0040] Figure 4The simplified representation shows a screen output of various load categories 91, 92, 93, 94, and 95. Load categories 91, 92, 93, 94, and 95 each correspond to load ranges of the crusher 50 or a component of the crusher 50, the crusher drive, or the transmission elements. A first load category, 91, encompasses loads such as those occurring when the crusher 50 is idling. A second load category, 92, corresponds to a range of lower loads, and a third load category, 93, to a range of somewhat higher loads on the crusher 50. A fourth load category, 94, encompasses the range of a desired load for the crusher 50. In this range, damage to or excessive wear of the crusher 50 due to overloading can be prevented. At the same time, a high throughput of the crusher 50 is achieved. Applied to the in Figure 3In the diagram shown, the fourth load category 94 lies in the range between the upper and lower limits 82, 83. A fifth load category 95 comprises a load range that leads to an overload of the crusher 50, the crusher drive or the transmission elements.

[0041] The measured load or the associated characteristic value of the crusher 50, a component of the crusher, the crusher drive, or the transmission element are assigned to a respective load category 91, 92, 93, 94, 95. If, within a certain time period (first period Δt 1 86.1, see Figure 3If the measured loads of crusher 50 or the values ​​of the associated parameter are assigned to a predetermined number of strokes of the fifth load category 95, the fill level of crusher 50 is reduced. A time window of a predetermined duration then elapses during which no determination or evaluation of the load of crusher 50 or the dependent parameter and / or no further adjustment of the fill level takes place. During this time window, for example, two minutes, the fill level of crusher 50 decreases. If the measured loads of crusher 50 or the values ​​of the associated parameter were assigned to the fourth load category 94, no change in the fill level occurs. If the measured loads of crusher 50 or the values ​​of the associated parameter were assigned to a predetermined second time period (second period Δt 2 , 86.3 in Figure 2If the load falls within the second and third load categories 92 and 93, the fill level of crusher 50 is increased. Assigning the measured loads to load categories 91, 92, 93, 94, and 95 allows for easy implementation of the process using appropriate software. This software can, for example, be integrated into a control unit of the material shredding plant 10.

[0042] According to the presentation in the Figure 1-4The load on the crusher 50 or a related parameter is thus determined. Particularly preferred is the measurement of the strain of a highly stressed component of the crusher 50, the transmission elements, or the crusher drive, which occurs as a result of a mostly periodic force application to the structure. However, other parameters characterizing the load on the crusher 50 can also be used for evaluation, for example, the load or movement behavior of a component of the crusher 50, the crusher drive, or the transmission elements between the crusher drive and the crusher 50.

[0043] The strain can be easily determined using at least one strain gauge 60. This is preferably attached to a component of the crusher, the crusher drive, or the transmission elements that is subject to particularly high mechanical stress. Mechanical stresses can be calculated from the strain measured by the strain gauge 60. These can be compared to the permissible stresses of the material used. The stress values ​​measured with each periodically occurring load can be assigned to load categories 91, 92, 93, 94, and 95. If the permissible continuous load of the material crushing plant 10 or the crusher 50 is exceeded for a predetermined period, the fill level of the crusher 50 is automatically adjusted until the load is again within a predetermined, permissible range. This control is preferably carried out using appropriately designed software.This regulates the material feed components depending on the specific load of the crusher 50 and the signal from the level sensor 61. The regulation is carried out in such a way that a maximum volume flow of material 73 to be crushed is always fed to the crusher 50 without overloading it.

[0044] Different material properties, such as feed size, particle size distribution, compressive strength, comminution index, and comminution ratios, lead to varying fill levels within the tolerable load range. The process detects the resulting load independently of these factors and adjusts the fill level of crusher 50 so that the load on crusher 50 stabilizes within a desired normal range. This is achieved by appropriately controlling the material feed components.

[0045] In the Figure 2In the illustrated embodiment, the strain gauge 60 is attached to the pressure plate 58. However, it is also conceivable to arrange the strain gauge 60 on another highly stressed component of the material shredding system 10. For example, the strain gauge 60 could be attached to the crushing arm 53 or to parts of the eccentric 54. It is also conceivable to employ other methods, such as optical methods, for determining the strain and thus the stress of the monitored component.

[0046] It is also conceivable to determine the movement behavior of at least one component of the crusher 50, the transmission elements, and / or the crusher drive in order to assess the load on the crusher. For example, a continuous or regulated, and therefore short-term, change in the rotational speed of the crusher drive can indicate a change in the load on the crusher 50. The operating parameters of the crusher drive (torque, power, fuel consumption, etc.) are also directly dependent on the load on the crusher 50 and can be evaluated accordingly.

Claims

1. A method for controlling the charging of a crusher (50), driven by a crusher drive via transmission elements, of a material comminution system (10) wherein material which is to be crushed (73), in particular stone material which is to be crushed, is fed to the crusher (50), wherein a filling level of the crusher, preferably at a crusher inlet, is determined using a filling level sensor (61) and wherein the volume flow of material (73) to be crushed which is fed to the crusher (50) is set and / or controlled according to the determined filling level, wherein the mechanical loading of the crusher (50) or a characteristic variable which is dependent on the mechanical loading of the crusher (50) is determined directly or indirectly, characterized in that the filling level of the crusher (50) is set according to the determined mechanical loading or the characteristic variable which is dependent thereon.

2. The method as claimed in claim 1, characterized in that the movement behavior of at least one component of the crusher (50), the transmission elements and / or the crusher drive is measured as a characteristic variable which is dependent on the mechanical loading of the crusher (50) and / or an operating state of the crusher drive is measured as a characteristic variable which is dependent on the mechanical loading of the crusher (50).

3. The method as claimed in claim 2, characterized in that for determining the mechanical loading of the at least one component of the crusher (50), the transmission elements and / or the crusher drive, the strain of the at least one component is determined.

4. The method as claimed in claim 3, characterized in that the strain is determined by at least one sensor, for example a strain gage (60).

5. The method as claimed in claim 3 or 4, characterized in that a mechanical stress of the at least one component of the crusher (50), the transmission elements or the crusher drive is determined from the strain and in that the filling level of the crusher (50) is set according to the mechanical stress of the at least one component of the crusher (50), the transmission elements or the crusher drive.

6. The method as claimed in one of claims 2 to 5, characterized in that for determining the movement behavior of the at least one component of the crusher (50), the transmission elements and / or the crusher drive, an acceleration is preferably determined by an acceleration sensor and / or a rotational speed and / or a rotational speed alteration is preferably determined by a rotational speed sensor.

7. The method as claimed in one of claims 2 to 6, characterized in that the operating state of the crusher drive is determined by a power output and / or by a torque and / or by an energy consumption and / or by a fuel consumption and / or by a rotational speed of the crusher drive.

8. The method as claimed in one of claims 1 to 7, characterized in that the filling level of the crusher (50) is reduced when the mechanical loading of the crusher (50) or a characteristic variable which is dependent on the mechanical loading of the crusher (50) exceeds a predetermined upper limit value (82) or when a characteristic variable which is inversely dependent on the mechanical loading of the crusher (50) falls below a predetermined lower threshold value and / or that the filling level of the crusher (50) is reduced when the mechanical loading of the crusher (50) or a characteristic variable which is directly dependent on the mechanical loading of the crusher (50) within a predetermined first time period Δt1 (86.1) has exceeded the predetermined upper limit value (82) with a predetermined frequency or over a predetermined duration or when a characteristic variable which is inversely dependent on the mechanical loading of the crusher (50) within the predetermined first time period Δt1 (86.1) has fallen below the predetermined lower threshold value with a predetermined frequency or over a predetermined duration.

9. The method as claimed in one of claims 1 to 8, characterized in that the filling level of the crusher (50) is increased when the mechanical loading of the crusher (50) or a characteristic variable which is directly dependent on the mechanical loading of the crusher (50) does not exceed a predetermined lower limit value (83) over a predetermined second time period Δt2 (86.3) or when a characteristic variable which is inversely dependent on the mechanical loading of the crusher (50) does not fall below a predetermined upper threshold value over the predetermined second time period Δt2 (86.3) and / or that the filling level of the crusher (50) is increased when the mechanical loading of the crusher (50) or a characteristic variable which is directly dependent on the mechanical loading of the crusher (50) exceeds the predetermined lower limit value (83) over the predetermined second time period Δt2 (86.3) no more than with a predetermined second frequency or longer than a predetermined duration or when a characteristic variable which is inversely dependent on the mechanical loading of the crusher (50) falls below the predetermined upper threshold value over the predetermined second time period no more than with a predetermined second frequency or longer than a predetermined duration.

10. The method as claimed in one of claims 1 to 9, characterized in that after reducing and / or increasing the filling level of the crusher (50), no further determination and / or evaluation of the mechanical loading of the crusher (50) or the characteristic variable which is dependent on the mechanical loading of the crusher (50) and / or no further setting of the filling level of the crusher (50) is carried out until a predetermined waiting time Δtblind1 (86.2), Δtblind2 (86.4) has elapsed.

11. The method as claimed in one of claims 1 to 10, characterized in that in each case the filling level of the crusher (50) is reduced and / or increased by a predetermined absolute value or in that in each case the filling level of the crusher (50) is reduced and / or increased by a value relative to the actual filling level.

12. The method as claimed in one of claims 1 to 11, characterized in that loading categories (91, 92, 93, 94, 95, 96), which in each case are assigned to a low loading, a desired loading or an excessive loading of the crusher (50), are established, in that successive specific mechanical loadings of the crusher (50) or successive specific values of the characteristic variable which is dependent on the mechanical loading of the crusher (50) are assigned in each case to a loading category.

13. The method as claimed in claim 12, characterized in that the filling level of the crusher (50) is reduced when over a predetermined first time span a predetermined number of determined loadings of the crusher (50) or values of the characteristic variable which is dependent on the loading are assigned to a loading category (91, 92, 93, 94, 95, 96) which is assigned to an excessive loading, in that the filling level of the crusher (50) is increased when over a predetermined second timespan a predetermined number of determined loadings or values of the characteristic variable which is dependent on the loading are assigned to a loading category (91, 92, 93, 94, 95, 96) which is assigned to a low load, and in that the filling level is not altered when the determined loadings or the values of the parameter which is dependent on the loading are assigned to a loading category (91, 92, 93, 94, 95, 96) which is assigned to a desired loading.

14. The method as claimed in one of claims 1 to 13, characterized in that when the loading of the crusher (50) changes periodically the maximum values of the loading of the crusher (50) or the values of the parameter, which is dependent on the loading of the crusher (50), assigned to the maximum values are determined and in that the filling level of the crusher (50) is set according to the maximum values of the loading of the crusher (50) or the values of the parameter, which is dependent on the loading of the crusher (50), assigned to the maximum values.

15. A control device for operating a material comminution system (10) comprising a crusher (50), wherein the control device is configured for - detecting and storing a mechanical loading of the crusher (50) or a characteristic variable which is dependent on the mechanical loading of the crusher, characterized in that the control device is configured for - setting the filling level of the crusher (50) according to the detected mechanical loading or the characteristic variable which is dependent thereon.