Method for operating an extruder, computer program, control device, and extruder
By detecting and adjusting the torque signal of the extruder and optimizing its operating point, the emergency shutdown problem caused by torque signal fluctuations in the prior art is solved, and stable operation at higher torque levels is achieved, and productivity and product quality are improved.
Patent Information
- Application Number
- CN202380073573.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-10-17
- Filing Date
- 2023-10-16
- Publication Date
- 2025-05-30
AI Technical Summary
When existing extruders process fiber-containing thermoplastics, due to the limitations of main driving power and mechanical strength, the process is limited, and the maximum speed and maximum power cannot be effectively utilized. The torque signal fluctuates rapidly, which can easily lead to emergency shutdown and reduce productivity.
By detecting the torque signal of the extruder, obtaining its maximum peak value, and comparing it with the preset maximum value, adjusting the torque of the screw shaft to optimize the operating point and ensuring stable operation at higher torque levels.
It realizes that under the premise of reliable production, optimize the operating points, improve the torque level, reduce the risk of emergency shutdown, and improve productivity and product quality.
Smart Images
Figure CN120076916A_ABST
Abstract
Description
Field of the Invention
[0001] The present invention relates to a method for operating an extruder. Furthermore, the present invention relates to a computer program, a control device, and an extruder. Background Art
[0002] The processing technology on an extruder (such as a twin-screw extruder) has various process limitations. For example, these process limitations may lie in the area of raw material input, the so-called feeding-limited process. Another typical process limitation lies in the drive power of the extruder, the so-called torque-limited process. Although the current modern extruders have a high power density, the processing of thermoplastics containing fibers (such as glass fibers) (such as polyamide (PA) or polybutylene terephthalate (PBT)) and other plastics is still always restricted by the main drive power of the extruder and / or the mechanical strength limitations of the components. In the case of good product quality, the process is implemented in the range of approximately 75% to 95% of the maximum speed of the extruder. Thus, almost the maximum power of the motor (such as an asynchronous motor) is exhausted. Usually, the maximum speeds in the range of 95% to 100% of the maximum speed are not used.
[0003] Like all processes, the torque-limited process also undergoes certain fluctuations. For example, these fluctuations may be caused by the dosing equipment, the material, but may also be caused by the normal fluctuations in the extrusion process. This may result in measurement parameters, such as the screw peak pressure or the torque of the main drive device, having a certain fluctuation range. In particular, the torque signal responds very quickly to process fluctuations because the torque signal may be significantly affected by the amount of material in the melting zone. The torque signal is a signal monitored in the control device. When the threshold value (related to the mechanical implementation of the device) is exceeded, this signal triggers an alarm and when the maximum value is exceeded, it causes the extruder to stop urgently or the safety clutch in the transmission system to disengage, so as to mechanically separate the motor from the screw shaft. However, the emergency stop results in a large amount of cleaning work and further manual intervention, which reduces the productivity of the extruder equipment (such as a mixing production line). In the worst case, permanent damage to the machine may also be unavoidable.
[0004] In order to avoid this emergency stop, the equipment operator selects a safe operating point at which the torque level has a significant gap from the maximum value. For this process, the extruder is usually operated at 80% to 90% of the maximum torque. Due to the uncertainty, from the perspective of the equipment operator, a lower torque level is often selected. However, since the equipment operator can only read the torque signal on the controller display screen at a low sampling rate, he cannot grasp the entire fluctuation range of the signal. Therefore, the equipment operator has no opportunity to obtain a well-founded data situation to evaluate the actual fluctuation range, especially in the case of severe process fluctuations.
[0005] However, facts have shown that it is impossible to optimize the operating point to a higher torque level on the premise of reliable production. Summary of the Invention
[0006] The object of the present invention is to structurally and / or functionally improve the method described at the beginning. In addition, the object of the present invention is to structurally and / or functionally improve the computer program described at the beginning. In addition, the object of the present invention is to structurally and / or functionally improve the control device described at the beginning and the extruder described at the beginning.
[0007] Therefore, in particular, the object of the present invention is to provide a method for operating an extruder, which can reduce or eliminate the problems pointed out in combination with the prior art. For example, one object is to be able to achieve an optimized operating point and / or ensure operation at a higher torque level on the premise of reliable production.
[0008] This object is achieved by a method having the features described in claim 1. In addition, this object is achieved by a computer program having the features described in claim 16. In addition, this object is achieved by a control device having the features described in claim 17 and an extruder having the features described in claim 18. The subject matter of the dependent claims, the description and / or the drawings are advantageous embodiments and / or improvements. In particular, the independent claims of one claim category can also be improved and / or combined similarly with the dependent claims of another claim category. Similarly, the device features and / or process features described below can be combined with each other and / or improved.
[0009] The method can be a method for operating an extruder or for operating the extruder. The extruder can have a barrel. The extruder can have at least one screw shaft, such as an extruder screw. The at least one screw shaft can be rotatably accommodated in the barrel. 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 can be rotatably driven. The at least one screw shaft can be rotatably driven by the motor, or can be driven by the motor in rotation, or can be driven in rotation by the motor. The extruder can have at least one drive shaft. The at least one drive shaft can be connected to the at least one screw shaft or can be connected to the at least one screw shaft. The extruder can have a frequency converter. The frequency converter can be connected to the motor. The extruder can have at least one measuring device for detecting, for example, the current torque. For this purpose, the at least one measuring device can have a corresponding sensor device. The torque can be the torque of the at least one drive shaft or the at least one screw shaft. The torque can be sensed or measured by means of the at least one measuring device. For example, the at least one measuring device can sense or measure the torque of only one drive shaft or screw shaft. Alternatively, the at least one measuring device can sense or measure the torque of two or all drive shafts or screw shafts. It is also possible to assign its own measuring device to each drive shaft or each screw shaft. Additionally or alternatively, the at least one measuring device can detect the torque of the transmission system and / or the torque at the clutch or coupling sleeve.
[0010] The method can include the step of detecting a torque signal. The torque signal can be related to the at least one drive shaft or the at least one screw shaft and / or the clutch / coupling sleeve and / or the transmission system. The torque signal can be a signal provided by the frequency converter or can be provided by the frequency converter as a signal. The torque signal can be a measurement signal provided by the at least one drive shaft or the at least one screw shaft or can be provided by the at least one drive shaft or the at least one screw shaft. The torque signal can be provided by the at least one measuring device for detecting torque or can be provided by the at least one measuring device for detecting torque. The torque signal can be continuously detected and / or provided or can be continuously detected and / or provided. The torque signal can be composed of a plurality of torque signals (for example, superimposed) or can be composed of a plurality of torque signals, for example, composed of a first torque signal of the first drive shaft or screw shaft and a second torque signal of the second drive shaft or screw shaft.
[0011] The method can include the step of obtaining (in particular, detecting) the maximum peak of the torque signal. The maximum peak can in particular be the largest and / or the significant peak. It can also be provided that at least one maximum peak of the torque signal is obtained. In particular, the detected torque signal can be analyzed with respect to the maximum peak within a defined time interval.
[0012] The method may include the steps of comparing the maximum peak value of the acquired torque signal with the maximum value preset for the torque. It may also be provided that at least one maximum peak value of the torque signal is compared with the maximum value preset for the torque. The maximum value of the torque may be the maximum allowable torque. The maximum value of the torque may be a set and / or calculated maximum value. For example, the maximum value of the torque may be set, defined, and / or calculated, or set, defined, and / or calculated especially by a control device (such as an extruder control device). The setting, definition, and / or calculation of the maximum value of the torque may be performed automatically. The maximum value of the torque may be set, defined, calculated, and / or correspondingly defined based on at least one process signal and / or process parameter, or set, defined, calculated, and / or correspondingly defined. For example, the process signal and / or process parameter may be the extrusion pressure or temperature, such as the material temperature or the housing temperature. Additionally or alternatively, the maximum value of the torque may be recipe-related, specifically, it may be set, defined, calculated, and / or defined according to the recipe, or set, defined, calculated, and / or defined according to the recipe. Additionally or alternatively, other values of the process parameters (such as limit values) may be recipe-related, specifically, they may be set, defined, calculated, and / or defined according to the recipe, or may be set, defined, calculated, and / or defined according to the recipe. The maximum value of the torque may be a value lower than the shutdown value (such as the emergency shutdown value). For example, the maximum value of the torque may be about 5% lower than the shutdown value.
[0013] The method may include the step of adjusting the torque of at least one screw shaft based on the result of the comparison. The adjustment of the torque of at least one screw shaft may be performed automatically, or semi-automatically or manually. The automatic or semi-automatic torque adjustment may be performed by a control device, such as an extruder control device. Additionally or alternatively, information or a signal may also be output so that the equipment operator can manually adjust the torque, for example, by setting or changing specific process parameters. The information or signal output may be an operation suggestion for the equipment operator.
[0014] Adjustment can be understood as decreasing or increasing the torque of the screw shaft. When the maximum peak value of the obtained torque is lower than the maximum value preset for the torque, the torque of at least one screw shaft can be increased. The torque of the screw shaft can be increased by means of increasing the throughput and / or decreasing the rotational speed. Increasing the throughput can be understood as adding or adding more materials, such as plastic materials and / or additives. Decreasing the rotational speed can be understood as decreasing the rotational speed of at least one screw shaft and / or at least one drive shaft. When the maximum peak value of the obtained torque reaches or exceeds the maximum value preset for the torque, the torque of at least one screw shaft can be decreased. The torque of the screw shaft can be decreased by means of decreasing the throughput and / or increasing the rotational speed. Decreasing the throughput can be understood as reducing the addition of materials, such as plastic materials and / or additives. Increasing the rotational speed can be understood as increasing the rotational speed of at least one screw shaft and / or at least one drive shaft. For example, when the maximum peak value of the obtained torque is lower than and / or higher than the maximum value preset for the torque, it may affect the material dosage and / or the rotational speed of at least one drive shaft and / or screw shaft.
[0015] In this method, a preset torque reference value can be provided or preset. The torque reference value can be predefined or calculated. The torque reference value can be or define a baseline. The torque reference value can be defined within a certain time interval. The torque reference value can be continuously calculated within a defined time interval during the operation of the extruder and / or calculated based on historical data, or can be continuously calculated within a defined time interval during the operation of the extruder and / or calculated based on historical data. The historical data can be determined under comparable conditions (such as formulation, screw configuration, etc.). The fluctuation range near the torque reference value can be analyzed and / or determined. This fluctuation range can be the fluctuation range of torque or a torque signal. The fluctuation range can be analyzed and / or determined within a defined time interval. A standard fluctuation range of torque or a torque signal can be defined based on, for example, the existing or detected data at the corresponding operating point, formulation, or process of the extruder. The existing or detected data can be used for training, for example, to define the standard fluctuation range according to the formulation and / or according to the process (such as screw configuration, side feeding, and / or exhaust, etc.) at the corresponding operating point. The maximum peak value of the torque signal can be obtained and / or determined based on the analysis of the fluctuation range and / or the standard fluctuation range.
[0016] The median or average value of the torque or torque signal can be calculated within a defined time interval. This can be done based on the detected torque signal and / or by looking back at a specific time interval (especially in the past, e.g., just past). During the operation of the extruder, the median or average value of the torque or torque signal is continuously calculated within a defined time interval and / or calculated based on historical data. The torque reference value can be the calculated median or average value. The fluctuation range around the calculated median or average value can be analyzed and / or determined within a defined time interval. By considering the median or average value, the calculation and / or analysis can be carried out more reliably. Thus, the throughput adjustment and / or speed adjustment can be carried out more accurately.
[0017] After each adjustment of the torque of at least one screw shaft, the steps of detecting the torque signal, obtaining the maximum peak of the torque signal, comparing the obtained maximum peak of the torque signal with the maximum value preset for the torque, and adjusting the torque of at least one screw shaft based on the result of the comparison can be continuously repeated, especially until the maximum peak of the corresponding obtained torque reaches or substantially reaches the maximum value preset for the torque. These steps can also be continuously repeated after each increase in throughput and / or decrease in speed until the maximum peak of the corresponding obtained torque reaches or substantially reaches the maximum value preset for the torque.
[0018] In this method, processes affecting the torque and / or process signals related to the process can be identified and / or detected. When a process affecting the torque and / or a process signal related to the process is identified or detected, the torque adjustment of at least one pre-planned or currently ongoing screw shaft can be stopped at least temporarily. For example, when a process affecting the torque and / or a process signal related to the process is identified or detected, a temporary or short-term adjustment of the torque of at least one screw shaft can be made. A process affecting the torque can be understood as, for example, a change in the material temperature during the refill or batching process of the input (material input). A change in the material temperature can be understood as an increase or decrease in the material temperature. A temporary or short-term adjustment can be understood as temporarily or short-term reducing or increasing the torque of at least one screw shaft. After the process affecting the torque ends, the torque of at least one screw shaft can be adjusted again to the previously existing value, such as the original value or the initial value. Process signals can be used to targetedly affect the process in the short term, especially to reduce torque peaks. Thus, foreseeable short-term effects do not cause the torque signal, specifically the maximum value, to be exceeded. For example, during refill and batching, the speed of at least one screw shaft can be adjusted short-term to avoid peaks that may cause the maximum allowable torque signal, specifically the maximum value, to be exceeded.
[0019] In this method, when the maximum peak value of the torque reaches or substantially reaches the maximum value preset for the torque, the adjustment of the torque of at least one screw shaft can be stopped. During the operation of the extruder, the fluctuation range can be continuously analyzed and / or the torque of at least one screw shaft can be adjusted as needed, for example, by increasing or decreasing the throughput and / or increasing or decreasing the rotational speed.
[0020] The detection of the torque signal and / or the adjustment of the torque of at least one screw shaft can be carried out in real time. The torque signal and / or the process signal and / or the data can be processed in real time, for example, by a control device (such as an extruder control device).
[0021] The computer program can be a computer program product. The computer program can be a computer program component or have at least one computer program component. The computer program can cause a control device, such as an extruder control device, and / or a control and / or computing unit / device, a control system, and / or an extruder, and / or a processor or a computer to execute the method described above / below. For this purpose, the computer program can have corresponding data sets and / or program code means and / or a storage medium for storing the data sets or the program. The computer program or the computer program component can be stored on a machine-readable medium, such as a storage medium.
[0022] The computer program can include program code means and / or commands for executing the method described above / below when the computer program is executed on at least one processor. The computer program / computer program component can include program code means and / or commands for executing at least one of the method steps described above / below when the computer program is executed on at least one processor, or for causing a control device, such as an extruder control device or an extruder, to execute at least one of the method steps described above / below.
[0023] For example, the computer program or the first computer program / first computer program component can include program code means and / or commands for executing the steps of the method described above / below when the computer program / computer program component is executed on at least one first processor or computer: detecting the torque signal, obtaining the maximum peak value of the torque signal, and comparing the obtained maximum peak value of the torque signal with the maximum value preset for the torque, or for causing a control device, such as an extruder control device or an extruder, to execute these steps. The first computer program / first computer program component can include program code means and / or commands for causing at least one first processor and / or computer to send data to and / or receive data from a second processor and / or computer when the computer program / computer program component is executed on at least one first processor and / or computer.
[0024] Additionally or alternatively, the computer program or the first computer program / computer program component may include program code means and / or commands for evaluating historical data and / or signals when executing the computer program / computer program component on at least one first processor or computer. The historical data and / or signals may be understood as data or signals that have been previously detected at comparable operating points, processes, and / or recipes.
[0025] The computer program or the second computer program / second computer program component may include program code means and / or commands for, when executing the computer program / computer program component on at least one second processor / computer, the steps of the method described above / below: adjusting the torque of at least one screw shaft based on the result of the comparison, or causing a control device (such as an extruder control device or an extruder) to perform this step. The second computer program / second computer program component may include program code means and / or commands for, when executing the computer program / computer program component on at least one second processor and / or computer, causing at least one second processor and / or computer to send data and / or receive data from the first processor and / or computer.
[0026] Additionally or alternatively, the computer program or the first computer program / computer program component, and / or the second computer program / second computer program component may include program code means and / or commands for, when executing the computer program / computer program component on at least one first processor or computer, for example, implementing the evaluation of current data and / or signals.
[0027] A distributed computer environment / processor environment may be implemented. For example, a networked client - server - system, a peer - to - peer network, and / or a cloud, such as cloud computing, may be set up. Parts of the computer program may not only be provided centrally, or may be provided dispersedly. For example, the second computer program / second computer program component may be executed by means of a control device (such as an extruder control device). The first computer program / first computer program component may be executed by means of a control device (such as an extruder control device), and / or may be executed by means of an external evaluation unit, or may be executed by means of cloud computing or in the cloud. The external evaluation unit may be connected to the control device. The control device (such as an extruder control device) may be connected to the cloud or cloud computing, for example, wired or wirelessly. For this purpose, the control device may have corresponding transmitting means and / or receiving means.
[0028] The control device for an extruder can be an extruder control device. The control device can be a controller. The control device can be adapted and / or set for use in an extruder or an extruder device. The control device can be adapted and / or set to perform the methods described above / below. The control device can have 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 control device can have a machine-readable memory, such as a storage medium. The computer program or computer program component can be stored in this memory. The control device can have a transmitting device and / or a receiving device. The control device can be designed and / or adapted to connect to an external storage medium or an external processor or computer and / or the cloud (such as cloud computing). The control device can have at least one measuring device for detecting the torque of at least one screw shaft and / or at least one drive shaft, or can be connected to a measuring device. The control device can have a frequency converter, or can be connected to a frequency converter. The control device can be designed and / or adapted to communicate and / or exchange data (such as signals) with the measuring device and / or the frequency converter.
[0029] An extruder can be designed for processing materials, such as plastic materials. The extruder can have a barrel, such as an extruder barrel. The extruder can have at least one screw shaft, such as an extruder screw. The at least one screw shaft can be rotatably accommodated in the barrel. The at least one screw shaft can be rotatably 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 can be rotationally driven. The at least one screw shaft can be rotationally driven by the motor, or can be rotationally driven through the motor, or can be rotationally driven by the motor. The extruder can have at least one drive shaft. The at least one drive shaft can be connected to the at least one screw shaft, or can be connected 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. For this purpose, the at least one measuring device can have a corresponding sensor device. The at least one measuring device can be designed for sensing or measuring torque. For example, the at least one measuring device can be designed for sensing or measuring the torque of only one drive shaft or screw shaft. Alternatively, the at least one measuring device can be designed for sensing or measuring the torque of two or all drive shafts or screw shafts. Each drive shaft or each screw shaft can be provided with a measuring device. Additionally or alternatively, the at least one measuring device can be designed for detecting the torque of the transmission system and / or the torque at the clutch or coupling sleeve. The extruder can be adapted and / or set for performing the method described above / below. The extruder can have a control device, such as an extruder control device. The control device can be designed as described above / below. The control device can be designed and / or adapted for communicating and / or exchanging data, such as signals, with the at least one measuring device and / or with the frequency converter.
[0030] In summary, in other words, an algorithm (such as a method) is also generated by the present invention for evaluating existing or detected signals (such as process signals for torque, rotational speed, pressure, temperature, and / or throughput, etc.) of an extruder (such as a twin-screw extruder). Then, the operating point can be adjusted in the direction of higher torque accordingly, for example, adjusting the rotational speed, throughput, and / or performing housing temperature control, etc. The algorithm can be trained with the existing data in the device, for example, to define a standard fluctuation range according to the recipe and / or according to the process (screw configuration, side feeding, exhaust, etc.) at the corresponding operating point. The algorithm can continuously calculate or obtain the median or average value of the torque signal in the operation of the extruder in a manner of looking back at a specific time interval. For example, the median or average value of the torque signal can be used as a baseline. The algorithm can use historical data for calculation, for example, as long as these historical data are generated under comparable conditions (recipe, screw configuration, etc.). Within this time interval, the fluctuation range near the median or average value (such as the baseline) can be analyzed to obtain the maximum peak value of the torque signal. If the peak value is lower than the maximum value set for the allowable maximum torque, the algorithm can automatically or semi-automatically, or through the necessary user input, increase the throughput of the extruder, for example, increasing it in very small steps such as about 1% of the total throughput, or increasing it according to a defined calculation model. The throughput can be increased linearly or non-linearly. The basis for increasing the throughput can be the dependence of the process influence variable on torque (such as determined by the algorithm). The preset, for example, set maximum value does not have to be the emergency shutdown value of the extruder, but can be a value that is a certain safety margin lower than the shutdown value (such as about 5% lower). After each throughput adjustment, the evaluation of the measurement signal, median or average value / baseline, the fluctuation range of the measurement signal, and / or the peak value that appears, etc., can be carried out again. The process parameters, such as torque, can be readjusted based on the new understanding. Therefore, the median or average value (such as the baseline) of the torque signal can, for example, continuously increase until the maximum peak value of the torque signal reaches the allowable or preset maximum value. Subsequently, the throughput increase can be stopped. In addition, the algorithm can analyze the fluctuation range of the torque signal during operation and / or adjust the throughput as needed. If the fluctuation range in the process becomes larger, the throughput can be reduced, for example, to avoid the risk of emergency shutdown. The steps of reducing the throughput can be carried out similarly to increasing the throughput and / or based on historical data or a mathematical calculation model. In some processes, the maximum throughput may be limited by peripheral equipment, such as through a dosing device or an output device, or limited by peripheral equipment, such as through a dosing device or an output device. Thus, it is feasible at any time to increase the throughput to optimize the torque. As an alternative to increasing the throughput, the rotational speed of the extruder, specifically one or more screw shafts, can also be reduced while keeping the throughput constant to increase and / or maximize the utilization of torque. This may result in a reduction in specific energy input.Especially for extruders in the field of large machinery, this can mean significant cost savings per kilogram of product produced. To design the algorithm more efficiently, more stably, and / or more predictably, other signals from the process chain, such as signals from dosing equipment, can be integrated into the analysis. Thus, potential influencing factors can be identified before the torque signal is affected and / or the operating point can be adjusted accordingly. The algorithm can be implemented on a control device, such as an extruder control device, or can be implemented on a control device, such as an extruder control device. Data can be processed in real time. Thereby, the algorithm can use real-time and / or higher-resolution data. Additionally or alternatively, combined calculations can be provided, where historical data / signals are evaluated on an external evaluation unit or in the cloud, and only current data / signals are acquired and / or calculated or evaluated and adjusted on or with the help of the control device.
[0031] By means of the present invention, the torque can be optimized. The operating point can be optimized to the torque limit. Thereby, the production capacity can be increased. For example, for an existing extruder in a reliable operating state, the maximum allowable torque and the accompanying throughput can be maximized, for example, automatically, semi-automatically, or manually. In many cases, better product quality is obtained along with the optimization of the torque (whether by increasing the throughput or reducing the rotational speed), because the product can be processed more gently. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings, where schematically and by way of example: Figure 1 A flowchart of one embodiment of a method for operating an extruder is shown; Figure 2 A flowchart of another embodiment of a method for operating an extruder is shown; and Figure 3 An extruder with a control device is shown. DETAILED DESCRIPTION OF THE INVENTION
[0033] Figure 1 A flowchart of one embodiment of a method for operating an extruder is schematically shown. The extruder includes at least one screw shaft rotatably received in a barrel and rotatably drivable by a motor. At least one screw shaft is coupled to at least one drive shaft. At least one drive shaft is coupled to the motor.
[0034] In step S11, a torque signal related to at least one drive shaft or screw shaft is detected. Thus, the torque signal corresponds to the torque of at least one drive shaft or screw shaft. For example, the torque signal can originate from a frequency converter, or can be provided by at least one measuring device for detecting torque, or can be provided by at least one measuring device for detecting torque.
[0035] In step S12, the maximum peak value of the torque signal is obtained, and in step S13, the maximum peak value of the obtained torque signal is compared with the maximum value preset for the torque.
[0036] In step S14, the torque of at least one screw shaft is adjusted based on the result of the comparison. The adjustment of the torque of at least one screw shaft can be carried out automatically, semi-automatically or manually. Here, when the maximum peak value of the obtained torque is lower than the maximum value preset for the torque, the torque of at least one screw shaft can be increased. The torque of at least one screw shaft can be increased by increasing the throughput and / or reducing the rotational speed. After each adjustment of the torque of at least one screw shaft or after each increase in the throughput and / or reduction in the rotational speed, steps S11 to S14 can be repeatedly carried out until the maximum peak value of the corresponding obtained torque reaches or substantially reaches the maximum value preset for the torque. When the maximum peak value of the torque reaches or substantially reaches the maximum value preset for the torque, the adjustment of the torque of at least one screw shaft can be stopped.
[0037] Figure 2 The flowchart of another embodiment of the method for operating an extruder is schematically shown. The extruder includes at least one screw shaft rotatably accommodated in a barrel and rotatably driven by a motor. At least one screw shaft is connected to at least one drive shaft. At least one drive shaft is connected to the motor.
[0038] In step S21, a torque signal related to at least one drive shaft or screw shaft is detected. Thus, the torque signal corresponds to the torque of at least one drive shaft or screw shaft. For example, the torque signal can be sourced from an inverter, or can be provided by at least one measuring device for detecting torque, or can be provided by at least one measuring device for detecting torque.
[0039] In step S22, a torque reference value is provided. Here, the median or average value of the detected torque or torque signal can be calculated within a defined time interval. Then, 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 value of the torque signal is obtained based on the analysis of the fluctuation range.
[0041] Subsequently, in step S25, the maximum peak value of the obtained torque signal is compared with the maximum value preset for the torque.
[0042] In step S26, the torque of at least one screw shaft is adjusted based on the result of the comparison. The adjustment of the torque of at least one screw shaft can be performed automatically, semi-automatically, or manually. Here, when the maximum peak value of the obtained torque is lower than the maximum value preset for the torque, the torque of at least one screw shaft can be increased. The torque of at least one screw shaft can be increased by increasing the throughput and / or reducing the rotational speed. After each adjustment of the torque of at least one screw shaft or after each increase in the throughput and / or reduction in the rotational speed, steps S21 to S26 can be repeated until the maximum peak value of the corresponding obtained torque reaches or substantially reaches the maximum value preset for the torque. When the maximum peak value of the torque reaches or substantially reaches the maximum value preset for the torque, the adjustment of the torque of at least one screw shaft can be stopped.
[0043] In addition, it is hereby supplemented that reference can be made to Figure 1 and its related description.
[0044] Figure 3 An extruder 100 with a control device 102 is schematically shown. The extruder includes a barrel 104 and at least one screw shaft 108 rotatably accommodated in the barrel 104 and rotatably driven by a motor 106. At least one screw shaft 108 is connected to at least one drive shaft, and at least one drive shaft is connected to the motor 106. In this embodiment, the extruder is designed as a twin-screw extruder and has two rotatably driven screw shafts 108, which are rotatably accommodated in the barrel 104. In addition, a feeding device 110 is provided for feeding materials, such as plastic materials, into the extruder, specifically into the screw shaft 108.
[0045] The control device can be connected to, specifically communicate with, and thus exchange data or signals with an inverter 112 and / or a measuring device 114. The inverter 112 can provide a torque signal related to at least one drive shaft or screw shaft 108 to the control device 102. The measuring device 114 is designed to detect or measure the torque of at least one or two screw shafts 108 and provide a related torque signal to the control device 102. The control device 102 and / or the extruder 100 is designed and / or set to perform the method described above / below.
[0046] As a supplement, in other aspects especially with reference to Figure 1 and Figure 2 and its related description.
[0047] "Can" especially represents an optional feature of the present invention. Therefore, there are also improved solutions and / or embodiments of the present invention that additionally or alternatively have a corresponding one feature or corresponding multiple features.
[0048] If necessary, isolated features may also be selected from the feature combinations disclosed herein and used in combination with other features to define the subject matter of the claims, provided that the structural and / or functional relationships that may exist between the features are removed. The order and / or number of method steps may be changed. List of reference numerals Step S11 for detecting a torque signal Step S12 for detecting the maximum peak value of the torque signal Step S13 for comparing the maximum peak value of the torque signal with a maximum value preset for the torque Step S14 for adjusting the torque of at least one screw shaft Step S21 for detecting a torque signal Step S22 for providing a torque reference value Step S23 for analyzing the fluctuation range near the torque reference value Step S24 for obtaining the maximum peak value of the torque signal Step S25 for comparing the maximum peak value of the torque signal with a maximum value preset for the torque Step S26 for adjusting the torque of at least one screw shaft 100 extruder 102 Control device 104 Barrel 106 Motor 108 Screw shaft 110 Batching device 112 Frequency converter 114 Measuring device
Claims
1. A method for operating an extruder (100), the extruder comprising at least one screw shaft (108) rotatably received in a barrel (104) and rotatably driven by a motor (106), the method comprising the steps: - Detecting (S11, S21) a torque signal associated with at least one drive shaft or screw shaft (108); - Obtaining (S12, S24) the maximum peak value of the torque signal; - Comparing (S13, S25) the obtained maximum peak value of the torque signal with a maximum value preset for the torque; and - Adjusting (S14, S26) the torque of the at least one screw shaft (108) based on the result of the comparison.
2. The method according to claim 1, wherein, when the obtained maximum peak value of the torque is lower than the maximum value preset for the torque, increasing the torque of the at least one screw shaft (108).
3. The method according to any one of the preceding claims, wherein, increasing the torque of the at least one screw shaft (108) by increasing the throughput and / or reducing the rotational speed, or reducing the torque of the at least one screw shaft (108) by reducing the throughput and / or increasing the rotational speed.
4. The method according to any one of the preceding claims, wherein, providing (S22) a torque reference value, analyzing (S23) the fluctuation range around the torque reference value, and obtaining (S24) the maximum peak value of the torque signal based on the analysis of the fluctuation range.
5. The method according to claim 4, wherein, calculating the median or average value of the torque or torque signal within a defined time interval, and the torque reference value is the calculated median or average value.
6. The method according to claim 5, wherein, continuously performing within a defined time interval during the operation of the extruder (100) and / or based on historical data the median or average value of the torque or torque signal.
7. The method according to any one of the preceding claims, wherein, the maximum value preset for the torque is set, defined, calculated and / or bounded based on at least one process signal or process parameter and / or according to a recipe, or set, defined, calculated and / or bounded based on at least one process signal or process parameter and / or according to a recipe.
8. The method according to any one of the preceding claims, wherein, after each adjustment of the torque of the at least one screw shaft (108), the steps are repeatedly executed until the obtained maximum peak value of the corresponding torque substantially reaches the maximum value preset for the torque.
9. The method according to any one of the preceding claims, wherein, identifying the process affecting the torque and / or the process signal associated with the process, and temporarily adjusting the torque of the at least one screw shaft (108) when the process affecting the torque and / or the process signal associated with the process is identified or detected.
10. The method according to claim 9, wherein, When a process affecting the torque and / or a process signal associated with the process is recognized or detected, the torque adjustment of the at least one screw shaft (108) that is pre-planned or currently in progress is stopped at least temporarily.
11. The method according to any one of the preceding claims, characterized in that a standard fluctuation range of the torque is defined based on data existing or detected especially at a corresponding operating point, formulation or process of the extruder (100).
12. The method according to any one of the preceding claims, characterized in that the adjustment of the torque of the at least one screw shaft (108) is carried out automatically, semi-automatically or manually.
13. The method according to any one of the preceding claims, characterized in that when the maximum peak value of the torque substantially reaches the maximum value preset for the torque, the adjustment of the torque of the at least one screw shaft (108) is stopped.
14. The method according to any one of the preceding claims, characterized in that during the operation of the extruder (100), the fluctuation range is continuously analyzed, and the torque of the at least one screw shaft (108) is adjusted as needed, especially by increasing or decreasing the throughput and / or increasing or decreasing the rotational speed.
15. The method according to any one of the preceding claims, characterized in that the detection of the torque signal and / or the adjustment of the torque of the at least one screw shaft (108) is carried out in real time, and / or the torque signal and / or the process signal and / or data are processed in real time, especially by a control device (102), such as an extruder control device (102).
16. A computer program that causes the control device (102) and / or the extruder (100) to execute the method according to any one of the preceding claims, and / or the computer program includes program code means for executing the method according to any one of the preceding claims or at least one of the method steps according to any one of the preceding claims when the computer program is executed on at least one processor.
17. A control device (102) for an extruder (100), wherein the control device (102) is adapted and set to execute the method according to at least one of claims 1 to 15, and / or wherein the control device (102) has at least one processor and the computer program according to claim 16.
18. An extruder (100) comprising a barrel (104) and at least one screw shaft (108) rotatably received in the barrel (104) and rotatably driven by a motor (106), wherein the extruder (100) is adapted and set to execute the method according to at least one of claims 1 to 15 and / or has the control device (102) according to claim 17.