Method of operating an extruder, computer program, control system and extruder

Abstract

A method for operating an extruder (100) having at least one screw shaft (108) rotatably received within a cylinder (104) and rotatably drivable by a motor (106), the method comprising the steps of: detecting (S11, S21) a torque signal associated with at least one drive shaft or screw shaft (108); detecting (S12, S24) a maximum peak in the torque signal; comparing (S13, S25) the detected maximum peak in the torque signal with a predetermined maximum torque; and adapting (S14, S26) the torque of the at least one screw shaft (108) based on the results of the comparison; and a computer program, a controller (102), and the extruder (100).

Description

[Technical Field]

[0001] The present invention relates to a method for operating an extruder, and also to a computer program, a controller and an extruder. [Background technology]

[0002] Processing processes in extruders, such as twin-screw extruders, have various process limitations. For example, the raw material feed area, known as the "inlet-limited process," is one example. Another typical process limitation is the extruder's drive power, known as the "torque-limited process." Despite the high power density of modern extruders, the processing of thermoplastics such as polyamide (PA) and polybutylene terephthalate (PBT), fibers such as glass fiber, and other plastics is limited by the extruder's main drive power and / or the mechanical strength of its components. For good product quality, the process can be run at approximately 75-95% of the extruder's maximum speed. This means that the maximum power of the motor, such as an asynchronous motor, is almost fully utilized. Often, 95-100% of the maximum speed is not utilized.

[0003] Like all processes, torque-limited processes are subject to certain fluctuations. These fluctuations can be caused by doping equipment or materials, for example, or by normal fluctuations in the extrusion process. This can result in measured variables, such as screw tip pressure and main drive torque, being subject to certain fluctuation ranges. The torque signal, in particular, is highly sensitive to the amount of material in the melt zone and therefore responds very quickly to process fluctuations. The torque signal is monitored by the control system, which issues a warning if a threshold (related to the system's mechanical design) is exceeded, and if a maximum value is exceeded, it can either shut down the extruder or open a safety clutch in the drive system to mechanically decouple the motor and screw shaft. However, an emergency shutdown requires time-consuming cleaning and further manual intervention, reducing the productivity of extrusion lines, such as compounding lines. In the worst case scenario, it cannot prevent permanent damage to the machinery.

[0004] To avoid such an emergency shutdown, system operators select a safe operating point where the torque level is far from the maximum. Typically, extruders for such processes operate at 80-90% of maximum torque. Due to uncertainty, system operators often operate at even lower torque levels. However, because system operators can only read the torque signal on the control display at a low sampling rate, they do not have the opportunity to recognize the signal's full range of variation. Therefore, system operators do not have the opportunity to obtain reliable data to assess the actual range of variation, especially in highly variable processes.

[0005] However, optimizing the operating point to higher torque levels has proven impossible while still maintaining manufacturing reliability. Summary of the Invention

[0006] The present invention is based on the problem of structurally and / or functionally improving the method as defined above. Furthermore, the present invention is based on the problem of structurally and / or functionally improving the computer program as defined above. Furthermore, the present invention is based on the problem of structurally and / or functionally improving the controller as defined above and the extruder as defined above.

[0007] It is therefore an object of the present invention to provide a method for operating an extruder that can reduce or eliminate the problems identified in connection with the prior art, for example, one object is to enable optimization of the operating point and / or to ensure reliable operation at higher torque levels.

[0008] This problem is solved by a method having the features of claim 1. Furthermore, this problem is solved by a computer program having the features of claim 16. Furthermore, this problem is solved by a controller having the features of claim 17 and an extruder having the features of claim 18. Advantageous and / or further embodiments are the subject of the dependent claims, the description and / or the accompanying drawings. In particular, independent claims of one claim category can also be developed and / or combined in the same way with dependent claims of another claim category. Similarly, features of the devices and methods described below can be combined and / or further developed.

[0009] The method may be for operating or functioning as an extruder. The extruder may have a cylinder. The extruder may have at least one screw shaft, such as an extruder screw. The at least one screw shaft may be rotatably received within the cylinder. For example, the extruder may have two screw shafts. The extruder may be a single-screw extruder, a multi-screw extruder, or a twin-screw extruder. The extruder may have a motor. The at least one screw shaft may be rotationally driven. The at least one screw shaft may be rotationally driven, or may be rotationally driven, by a motor. The extruder may have at least one drive shaft. The at least one drive shaft may be coupled, or may be coupled, to the at least one screw shaft. The extruder may have a frequency converter. The frequency converter may be coupled to the motor. The extruder may have at least one measuring device for detecting torque, e.g., applied torque. The at least one measuring device may have a corresponding sensor system for this purpose. The torque can be the torque of at least one drive shaft or at least one screw shaft. The torque can be sampled or measured by at least one measuring device. For example, the at least one measuring device can sample or measure the torque of only one drive shaft or screw shaft. Alternatively, the at least one measuring device can sample or measure the torque of two or all drive shafts or screw shafts. A measuring device can also be assigned or associated with each drive shaft or each screw shaft. Additionally or alternatively, the at least one measuring device can detect the torque of the drive train and / or the torque of a clutch or clutch sleeve.

[0010] The method may include the following steps: detecting a torque signal. The torque signal may be related to at least one drive shaft or at least one screw shaft and / or a clutch / clutch sleeve and / or a drive train. The torque signal may be provided or can be a signal from a frequency inverter. The torque signal may be provided or can be a measurement signal from at least one drive shaft or at least one screw shaft. The torque signal may be provided or can be from at least one measurement device for detecting torque. The torque signal may be continuously detected and / or provided. The torque signal may be a plurality of torque signals, for example, summing a first torque signal of a first drive shaft or screw shaft and a second torque signal of a second drive shaft or screw shaft.

[0011] The method may comprise the following steps: detecting a maximum peak of the torque signal, in particular the detected torque signal. The maximum peak may in particular be a maximum peak value and / or a significant peak value. Also, at least one maximum peak of the torque signal may be detected. The detected torque signal may be analysed in relation to the maximum peak, in particular over a predetermined time interval.

[0012] The method may include the following steps: comparing a maximum peak of the detected torque signal with a predetermined maximum value for torque; comparing at least one maximum peak of the torque signal with a predetermined maximum value for torque; The maximum torque value may be a maximum allowable torque; The maximum torque value may be a set and / or calculated maximum value; For example, the maximum torque value may be set, defined, and / or calculated by a controller, particularly an extruder controller; The setting, definition, and / or calculation of the maximum torque may be automatic; The maximum torque value may be set, defined, calculated, and / or accordingly limited based on at least one process signal and / or process parameter; The process signal and / or process parameter may be, for example, a discharge pressure or a temperature, such as a material temperature or a housing temperature; Additionally or alternatively, the maximum torque value may depend on a recipe or may be set, defined, calculated, and / or limited according to a recipe; Additionally or alternatively, other values, such as limit values ​​of process parameters, may depend on a recipe or may be set, defined, calculated, and / or limited according to a recipe; The maximum torque value may be less than or equal to a shutdown value, such as an emergency shutdown value. For example, the maximum torque value may be approximately 5% below the shutdown value.

[0013] The method may include the following steps: Adapting the torque of at least one screw shaft based on the result of the comparison. The adjustment of the torque of the at least one screw shaft may be automatic, semi-automatic, or manual. The automatic or semi-automatic adjustment of the torque may be performed by a controller, such as an extruder controller. Additionally or alternatively, information or a signal may be output so that a system operator can manually adjust the torque, for example by setting or changing certain process parameters. The output information or signal may be a recommendation to the system operator.

[0014] Adaptation can be understood as a decrease or increase in the torque of the screw shaft. The torque of at least one screw shaft can be increased if the maximum peak of the detected torque is equal to or less than a specified maximum torque. The torque of the screw shaft can be increased by increasing the throughput and / or by decreasing the rotation speed. Increasing the throughput can be understood as adding or increasing the amount of added material, such as plastic material and / or additives. Reducing the rotation speed can be understood as reducing the speed of at least one screw shaft and / or at least one drive shaft. The torque of at least one screw shaft can be reduced if the maximum peak of the detected torque reaches or exceeds a specified maximum torque. The torque of the screw shaft can be reduced by decreasing the throughput and / or by increasing the speed. Reducing the throughput can be understood as reducing the amount of added material, such as plastic material or additives. Increasing the rotation speed can be understood as increasing the rotation speed of at least one screw shaft and / or at least one drive shaft. The material doping and / or the rotation speed of at least one drive shaft and / or screw shaft can be influenced, for example, if the maximum peak of the detected torque is below and / or above a predetermined maximum value of the torque.

[0015] In this case, a torque reference value can be provided or specified. The torque reference value can be predefined or calculated. The torque reference value can also be a baseline or defined. A time interval can be defined. The torque reference value can be continuously calculated over a defined time interval during operation of the extruder and / or based on historical data. The historical data can be determined under comparable conditions, such as a recipe, screw configuration, etc. A variation range around the torque reference value can be analyzed and / or determined. The variation range can be a variation range of the torque or torque signal. The variation range can be analyzed and / or determined over a defined time interval. A standard variation range of the torque or torque signal can be defined or determined based on existing or detected data, for example, at a corresponding operating point, recipe, or process of the extruder. Training can be performed using existing or detected data to define, for example, standard variation ranges at corresponding operating points depending on the recipe and / or process (screw configuration, side feeding, degassing, etc.) Based on the analysis of the variation ranges and / or standard variation ranges, the maximum peaks in the torque signal can be detected and / or identified.

[0016] The median or average value of the torque or torque signal can be calculated for a defined time interval. This can be done based on recorded torque signals and / or looking back into a specific time interval, in particular into the past, for example the immediate past. Calculation of the median or average value of the torque or torque signal for a defined time interval can be performed continuously during operation of the extruder and / or based on historical data. The torque reference value can be the calculated median or average value. The range of variation can be analyzed and / or determined for a defined time interval around the calculated median or average value. Including the median or average value allows for more reliable calculations and / or analyses. This allows for more accurate throughput and / or speed adjustments.

[0017] After each adjustment of the torque of the at least one screw shaft, steps such as detecting a torque signal, detecting a maximum peak of the torque signal, comparing the detected maximum peak of the torque signal with a predetermined maximum torque value, and adjusting the torque of the at least one screw shaft based on the result of the comparison may be repeatedly performed, in particular until the detected maximum torque peak in each case reaches or substantially reaches the predetermined maximum torque value. These steps may also be repeatedly performed with each increase in throughput and / or decrease in rotation speed until the detected maximum torque peak in each case reaches or substantially reaches the predetermined maximum torque value.

[0018] In this method, a torque-influencing process and / or a process signal related to this process can be recognized and / or detected. When a torque-influencing process and / or a process signal related to this process is recognized and / or detected, a previously planned or currently implemented adjustment of the torque of at least one screw shaft can be at least temporarily stopped. For example, the torque of at least one screw shaft can be temporarily or short-term adjusted when a torque-influencing process and / or a process signal related to this process is recognized or detected. A torque-influencing process can be understood to mean, for example, a change in material temperature, such as feeding, material supply, replenishment, or doping. A change in material temperature can be understood to mean an increase or decrease in material temperature. A temporary or short-term adjustment can be understood to mean a temporary or short-term decrease or increase in the torque of at least one screw shaft. After completion of the torque-influencing process, the torque of at least one screw shaft can be reset to a previous value, such as an original or initial value. The process signal can be used to influence the short-term process, particularly to reduce torque peaks. This means that foreseeable short-term effects do not result in the permissible torque signal or maximum value being exceeded, for example, during refilling of the doping part, the rotational speed of at least one screw shaft can be adapted in the short term to avoid peaks that exceed the maximum permissible torque signal or maximum value.

[0019] In this method, the adaptation of the torque of the at least one screw shaft can be stopped when the maximum torque peak reaches or substantially reaches a predetermined maximum torque value. During operation of the extruder, the variation range can be continuously analyzed and / or the torque of the at least one screw shaft can be adjusted as needed, for example by increasing or decreasing the throughput and / or increasing or decreasing the rotation speed.

[0020] The detection of the torque signal and / or the adaptation of the torque of the at least one screw shaft can be performed in real time. The torque signal and / or process signals and / or data can be processed in real time in a controller, such as, for example, an extruder controller.

[0021] The computer program may be a computer program product. The computer program may be a computer program component or may have at least one computer program component. The computer program may cause a controller, such as an extruder controller, and / or a controller and / or a computing device, a control system, and / or an extruder, and / or a processor or a computer to perform the methods described above and / or below. To this end, the computer program may include corresponding data records and / or program code means and / or a storage medium for storing the data records and / or programs. The computer program or computer program component may be stored on a computer-readable medium, such as a storage medium.

[0022] The computer program may comprise program code means and / or instructions for performing the above and / or below described methods when the computer program is run on at least one processor. The computer program / computer program component may comprise program code means and / or instructions for performing at least one of the above and / or below described method steps, or for causing an extruder controller or a controller such as an extruder to perform at least one of the above and / or below described method steps, when the computer program is run on at least one processor.

[0023] For example, the computer program or first computer program / computer program component may include program code means and / or instructions for performing, or causing a controller, such as an extruder controller, or an extruder to perform, the steps of detecting a torque signal, detecting a maximum peak in the torque signal, and comparing the detected maximum peak in the torque signal with a predetermined maximum torque value of the above and / or below methods when the computer program / computer program component is executed on at least a first processor or computer. The first computer program / computer program component may include program code means and / or instructions for causing, when executed on the at least one first processor and / or computer, the computer program / computer program component to send data to and / or receive data from a second processor and / or computer.

[0024] Additionally or alternatively, the computer program or first computer program / computer program component may include program code means and / or instructions for analyzing historical data and / or signals when the computer program / computer program component is executed on at least the first processor or computer. Historical data and / or signals may be understood to mean data and / or signals previously detected at comparable operating points, processes and / or recipes.

[0025] The computer program or second computer program / computer program component may comprise program code means and / or instructions for performing, or causing an extruder controller or a controller of an extruder or the like to perform, the step of adapting the torque of at least one screw shaft based on the results of the comparison of the above and / or below described methods, when the computer program / computer program component is executed on at least one second processor and / or computer. The second computer program / computer program component may comprise program code means and / or instructions for causing, when the computer program / computer program component is executed on the at least one second processor and / or computer, to send data to and / or receive data from the first processor and / or computer.

[0026] Additionally or alternatively, the computer program or the first and / or second computer program / computer program components may comprise program code means and / or instructions for evaluating current data and / or signals, e.g. in real time, when the computer program / computer program components are executed on at least the first processor or computer.

[0027] A distributed computing / processor environment can be implemented. For example, a networked client-server system, a peer-to-peer network, and / or a cloud, such as a computer cloud, can be provided. Parts of the computer program can be provided centrally or decentrally. For example, a second computer program / a second computer program component can be executed by a controller, such as an extruder controller. A first computer program / a first computer program component can be executed by a controller, such as an extruder controller, and / or by an external evaluation unit, or by or within a computer cloud. The external evaluation unit can be connected to the controller. A controller, such as an extruder controller, can be connected to the cloud or computer cloud, for example, by wire or wirelessly. The controller can have corresponding transmitting and / or receiving devices for this purpose.

[0028] The controller for the extruder can be an extruder controller. The controller can be a control unit. The controller can be configured and / or defined for use in an extruder or extruder system. The controller can be arranged and / or defined to implement the methods described above and / or below. The controller can be comprised of at least one processor and / or computer, such as a microcomputer, and / or a computer program and / or at least one computer program component. The controller can have a computer-readable memory, such as a storage medium. The computer program or computer program component can be stored in the memory. The controller can have a transmitting device and / or a receiving device. The controller can be designed and / or configured to connect to an external storage medium or an external processor or computer and / or a cloud, such as a computer cloud. The controller can have or be connected to at least one measuring device for detecting the torque of at least one screw shaft and / or at least one drive shaft. The controller can have or be connected to a frequency converter. The controller may be designed and / or configured to communicate with at least one measurement device and / or with a frequency converter and / or to exchange data such as signals.

[0029] The extruder can be designed for processing materials such as plastic materials. The extruder can have a cylinder, such as an extruder cylinder. The extruder can have at least one screw shaft, such as an extruder screw. The at least one screw shaft can be rotatably received within the cylinder. The at least one screw shaft can be rotationally driven. For example, the extruder can have two screw shafts. The extruder can be a single-screw extruder, a multi-screw extruder, or a twin-screw extruder. The extruder can have a motor. The at least one screw shaft is or can be rotationally driven by a motor. The extruder can have at least one drive shaft. The at least one drive shaft can be or can be coupled to the at least one screw shaft. The extruder can have a frequency converter. The frequency converter can be coupled to the motor. The extruder can have at least one measuring device for detecting the torque of the at least one screw shaft or the at least one drive shaft. The at least one measuring device can have a corresponding sensor system for this purpose. At least one measuring device can be designed to sample or measure torque. For example, at least one measuring device can be designed to sample or measure torque on only one drive shaft or screw shaft. Alternatively, at least one measuring device can be designed to sample or measure torque on two or all drive shafts or screw shafts. A measuring device can be assigned to each drive shaft or each screw shaft. Additionally or alternatively, at least one measuring device can be designed to detect torque on a drive train and / or to detect torque on a clutch or clutch sleeve. The extruder can be configured and / or defined to implement the methods described above and / or below. The extruder can have a controller, such as an extruder controller.The controller may be designed as described above and / or below. The controller may be configured and / or designed to communicate and / or exchange data, such as signals, with at least one measurement device and / or with a frequency converter.

[0030] In other words, the present invention provides an algorithm, such as a method, for evaluating existing or detected signals, e.g., process signals, particularly related to torque, speed, pressure, temperature, and / or throughput of an extruder, e.g., a twin-screw extruder. The operating point can then be adapted to achieve higher torque, e.g., by adjusting speed, throughput, housing temperature control, etc. The algorithm can be trained using existing data from the system to define a standard variation range for the corresponding operating point, e.g., depending on the recipe and / or process (screw configuration, side feed, degassing, etc.). The algorithm can look back to a specific time interval in the past to generate or determine a median or average value of the torque signal continuously during extruder operation, e.g., as a baseline. The algorithm can use historical data for calculations, e.g., if these were generated under comparable conditions (recipe, screw configuration, etc.). The variation range around the median or average value (e.g., baseline) can be analyzed to detect the maximum peak of the torque signal during the time interval. If these peaks are below a set maximum value for the maximum allowable torque, the algorithm can automatically or semi-automatically increase the extruder throughput, for example, in very small steps of 1% of the total throughput, or according to a defined calculation model, or automatically or semi-automatically, or upon request from the user. The increase in throughput can be linear or nonlinear. It can be based on the dependence of process-influencing variables on torque, for example, as determined by the algorithm. The predetermined, e.g., set, maximum value does not need to be a value for an emergency shutdown of the extruder, but rather a value with a certain degree of certainty below the shutdown value, for example, about 5% lower. After each throughput adaptation, the measurement signal, median or mean value / baseline, fluctuation range of the measurement signal, and / or occurring peaks can be analyzed again. Based on the new knowledge, process parameters such as torque can be adapted again. As a result, the median or mean value (e.g., baseline) of the torque signal can be continuously increased, for example, until the maximum peak of the torque signal reaches the allowable maximum value or a predetermined maximum value.The increase in throughput can then be stopped. The algorithm can continue to analyze the torque signal's fluctuation range during operation and / or adapt the throughput as needed. If the fluctuation range increases during the process, the throughput can be reduced, for example, to avoid the risk of an emergency shutdown. The step of reducing the throughput can be performed in a similar manner to the step of increasing the throughput and / or based on historical data or mathematical calculation models. Depending on the process, the maximum throughput is or can be limited by peripheral devices such as doping or discharging devices. Therefore, increasing the throughput to optimize the torque is not always possible. Instead of increasing the throughput, the extruder or screw shaft speed can be reduced while maintaining the same throughput in order to increase and / or maximize the torque. As a result, the specific input energy can be reduced. For extruders, especially in large machine areas, this means a significant cost reduction per kg of product produced. To make the algorithm more efficient, more robust, and / or more predictive, other signals from the process chain, such as signals from doping devices, can be integrated into the analysis. This allows potential effects on the torque signal to be recognized before they have an effect and / or the operating point to be adapted accordingly. The algorithm can be implemented in a controller, such as an extruder controller. Data can be processed in real time. The algorithm can therefore make use of real-time data and / or higher resolution data. Additionally or alternatively, historical data / signals can be evaluated in an external evaluation unit or on the cloud, and composite calculations can be provided where only current data / signals and adaptations are detected and / or calculated or evaluated on or by the controller.

[0031] The present invention allows for torque optimization. The torque limit operating point can be optimized. As a result, productivity can be increased. The maximum allowable torque and associated throughput maximization can be utilized, for example, automatically, semi-automatically, or manually, in an existing extruder, while remaining operationally safe. Optimizing torque often results in improved product quality, as the product can be treated more gently, whether at increased throughput or reduced speed. [Brief explanation of the drawings]

[0032] In the following, embodiments of the invention will be explained in more detail with reference to the figures, which show, diagrammatically and exemplarily: [Figure 1] FIG. 1 shows a flow chart of an example process for operating an extruder. [Figure 2] FIG. 2 shows a flow chart of a further variation of the method for operating an extruder. [Figure 3] FIG. 1 shows an extruder with a controller. DETAILED DESCRIPTION OF THE INVENTION

[0033] 1 is a schematic flow chart of an example method of operating an extruder. The extruder includes at least one screw shaft rotatably received within a cylinder and rotationally driven by a motor. The at least one screw shaft is coupled to at least one drive shaft. The at least one drive shaft is coupled to the motor.

[0034] In step S11, a torque signal associated with at least one drive shaft or screw shaft is detected. The torque signal thus corresponds to the torque of the at least one drive shaft or screw shaft. The torque signal may be, for example, provided by a frequency converter or by at least one measuring device for detecting torque.

[0035] In step S12, the maximum peak of the torque signal is detected, and in step S13, the detected maximum peak of the torque signal is compared with a preset maximum torque value.

[0036] In step S14, the torque of the at least one screw shaft is adapted based on the comparison result. The torque of the at least one screw shaft can be adapted automatically, semi-automatically, or manually. The torque of the at least one screw shaft can be increased if the maximum peak of the detected torque is equal to or less than a predetermined maximum torque. The torque of the at least one screw shaft can be increased by increasing the throughput and / or decreasing the rotation speed. After each adaptation of the torque of the at least one screw shaft or each increase in the throughput and / or each decrease in the rotation speed, steps S11 to S14 can be repeatedly performed until each maximum peak of the detected torque reaches or substantially reaches the predetermined maximum torque. Then, the adaptation of the torque of the at least one screw shaft can be stopped when the maximum peak of the torque reaches or substantially reaches the predetermined maximum torque.

[0037] 2 is a schematic flow chart of a further variation of a method for operating an extruder. The extruder comprises at least one screw shaft rotatably received in a cylinder and driven to rotate by a motor. The at least one screw shaft is coupled to at least one drive shaft. The at least one drive shaft is coupled to the motor.

[0038] In step S21, a torque signal associated with at least one drive shaft or screw shaft is detected. The torque signal thus corresponds to the torque of the at least one drive shaft or screw shaft. The torque signal can be generated, for example, from a frequency converter or provided by at least one measuring device for detecting torque.

[0039] In step S22, a torque reference value is provided. The median or average value of the detected torque or torque signal can be calculated over a predetermined time interval. The torque reference value is the calculated median or average value.

[0040] In step S23, the fluctuation range around the torque reference value is analyzed, and in step S24, the maximum peak of the torque signal is detected based on the analysis of the fluctuation range.

[0041] In step S25, the maximum peak of the detected torque signal is compared with a predetermined maximum torque value.

[0042] In step S26, the torque of the at least one screw shaft is adapted based on the comparison result. The adaptation of the torque of the at least one screw shaft can be performed automatically, semi-automatically, or manually. The torque of the at least one screw shaft can be increased when the maximum peak of the detected torque is equal to or less than a predetermined maximum torque. The torque of the at least one screw shaft can be increased by increasing the throughput and / or decreasing the rotation speed. After each adaptation of the torque of the at least one screw shaft, or each increase in the throughput and / or each decrease in the rotation speed, steps S21 to S26 can be repeatedly performed until the maximum peak of the detected torque reaches or substantially reaches the predetermined maximum torque. Then, the adaptation of the torque of the at least one screw shaft can be stopped when the maximum peak of the torque reaches or substantially reaches the predetermined maximum torque.

[0043] See also, in particular, FIG. 1 and the associated description.

[0044] 3 shows a schematic diagram of an extruder 100 equipped with a controller 102. The extruder comprises a cylinder 104 and at least one screw shaft 108 rotatably received in the cylinder 104 and driven in rotation by a motor 106. The at least one screw shaft 108 is coupled to at least one drive shaft coupled to the motor 106. In this embodiment, the extruder is designed as a twin-screw extruder and has two rotatably drivable screw shafts 108 rotatably received in the cylinder 104. Furthermore, a material doping section 110 is provided for feeding a material, for example a plastic material, to the extruder or the screw shafts 108.

[0045] The controller may be connected to or in communication with the frequency converter 112 and / or the measurement device 114, and thus may exchange data or signals. The frequency converter 112 may provide the controller 102 with a torque signal related to at least one drive shaft or screw shaft 108. The measurement device 114 is designed to detect or measure the torque of at least one or both screw shafts 108 and provide the related torque signal to the control unit 102. The control unit 102 and / or the extruder 100 are designed and / or intended to carry out the methods described above and / or below.

[0046] Additionally, see particularly Figures 1 and 2 and the associated description.

[0047] In particular, "can" refers to any feature of the invention, and therefore there may be further embodiments and / or example embodiments of the invention that additionally or alternatively have each feature or characteristic.

[0048] Where necessary, isolated features may be selected from the combinations of features disclosed herein and used in combination with other features to define the subject matter of the claims, while resolving structural and / or functional relationships that may exist between the features. The order and / or number of method steps may be varied. [Explanation of symbols]

[0049] S11: Step for detecting torque signal (Schritt zum Erfassen eines Drehmomentsignals) S12: Step for detecting the maximum peak of the torque signal (Schritt zum Erfassen von maximalen Peaks des Drehmomentsignals) S13: Comparing the maximum peak of the torque signal with a predetermined maximum torque value. (Schritt zum Vergleichen der maximalen Peaks des Drehmomentsignals mit einem vorgegebenen Maximalwert fuer das Drehmoment) S14 Adapting the torque of at least one screw shaft (Schritt zum Anpassen des Drehmoments der zumindest einen Schneckenwelle) S21: Torque signal detection step (Schritt zum Erfassen eines Drehmomentsignals) S22 Step for providing torque reference value (Schritt zum Bereitstellen eines Drehmoment-Referenzwerts) S23: Step to analyze the fluctuation range around the torque reference value (Schritt zum Analysieren einer Schwankungsbreite um den Drehmoment-Referenzwert) S24: Step for detecting the maximum peak of the torque signal (Schritt zum Erfassen von maximalen Peaks des Drehmomentsignals) S25: Comparing the maximum peak of the torque signal with a predetermined maximum torque value. (Schritt zum Vergleichen der maximalen Peaks des Drehmomentsignals mit einem vorgegebenen Maximalwert fuer das Drehmoment) S26 Adapting the torque of at least one screw shaft (Schritt zum Anpassen des Drehmoments der zumindest einen Schneckenwelle) 100 Extruder 102 Control System 104 Cylinder 106 Motor 108 Screw shaft (Schneckenwelle) 110 Material Doping Section 112 Frequency converter 114 Measuring devices

Claims

1. 1. A method of operating an extruder (100) having at least one screw shaft (108) rotatably received within a cylinder (104) and rotatably drivable by a motor (106), comprising: - detecting (S11, S21) a torque signal associated with at least one drive shaft or screw shaft (108); - detecting the maximum peak of said torque signal (S12, S24); a step (S13, S25) of comparing the detected maximum peak of the torque signal with a predetermined maximum torque; - adapting (S14, S26) the torque of said at least one screw shaft (108) based on the result of said comparison; A method comprising:

2. If the maximum peak of detected torque is less than or equal to the predetermined maximum torque, the torque of the at least one screw shaft (108) is increased. The method of claim 1.

3. the torque of said at least one screw shaft (108) is increased by increasing the throughput and / or decreasing the speed, or The torque of the at least one screw shaft (108) is reduced by decreasing the throughput and / or increasing the speed.

3. The method according to claim 1 or 2.

4. A torque reference value is provided (S22); A range of variation around the torque reference value is analyzed (S23), The maximum peak of the torque signal is detected based on the analysis of the fluctuation range (S24).

4. The method according to any one of claims 1 to 3.

5. a median or mean value of the torque or torque signal is calculated over a predetermined time interval; the torque reference value is the calculated median or average value; The method of claim 4.

6. Calculation of the median or average value of the torque or torque signal for a predetermined time interval is performed continuously during operation of the extruder (100) and / or based on historical data. The method of claim 5.

7. the predetermined maximum value of the torque is adjusted, defined, calculated and / or limited based on at least one process signal or process parameter and / or in dependence on a recipe; 7. The method according to any one of claims 1 to 6.

8. after each step of adapting the torque of the at least one screw shaft (108), steps are repeatedly performed until the maximum peak of the detected torque substantially reaches the predetermined maximum value of the torque.

8. The method according to any one of claims 1 to 7.

9. a process affecting said torque and / or a process signal related to said process is detected; a temporary adaptation of the torque of the at least one screw shaft (108) is performed when a process affecting the torque and / or a process signal related to this process is recognized or detected.

9. The method according to any one of claims 1 to 8.

10. a previously planned or currently performed adaptation of the torque of the at least one screw shaft (108) is at least temporarily stopped when a process affecting the torque and / or a process signal related to this process is recognized or detected.

10. The method of claim 9.

11. The standard variation range of the torque is defined based on existing or detected data, in particular at a corresponding operating point, recipe or process of the extruder (100); 11. The method of any one of claims 1 to 10.

12. The adaptation of the torque of the at least one screw shaft (108) is performed automatically, semi-automatically, or manually.

12. The method of any one of claims 1 to 11.

13. the adaptation of the torque of the at least one screw shaft (108) is stopped when the maximum peak of the torque substantially reaches the predetermined maximum value of the torque.

13. The method of any one of claims 1 to 12.

14. During operation of the extruder (100), the variation range is continuously analyzed and the torque of the at least one screw shaft (108) is adjusted as necessary, in particular by increasing or decreasing the throughput and / or increasing or decreasing the rotational speed.

14. The method of any one of claims 1 to 13.

15. said detecting of said torque signal and / or said adapting of said torque of said at least one screw shaft (108) is performed in real time; and / or said torque signals and / or process signals and / or data are processed in real time in a controller (102), in particular in an extruder controller (102); 15. The method of any one of claims 1 to 14.

16. A computer program comprising: causing the controller (102) and / or the extruder (100) to perform the method of any one of claims 1 to 15; and / or 16. A computer program comprising program code means for causing, when the computer program is run on at least one processor, to perform the method according to any one of claims 1 to 15 or at least one step of the method according to any one of claims 1 to 15. Computer program.

17. A controller (102) for an extruder (100), comprising: The controller (102) is configured and configured to perform the method of any one of claims 1 to 15; and / or The controller (102) comprises at least one processor and a computer program according to claim 16. controller.

18. An extruder (100) having a cylinder (104) and at least one screw shaft (108) rotatably received within the cylinder (104) and rotatably drivable by a motor (106), The extruder (100) is configured and configured to perform the method of any one of claims 1 to 15 and / or comprises a controller (102) according to claim 17. Extruder.

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