Operation of a paper machine with a run interruption preset scheme
Patent Information
- Application Number
- CN202580024756.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-04-05
- Filing Date
- 2025-04-03
- Publication Date
- 2026-10-30
Smart Images
Figure CN123023007A_ABST
Abstract
Description
[0001] The present invention relates to a method and system for operating a machine (“paper machine”) for manufacturing paper, cardboard, paperboard, etc., wherein the production operation of the paper machine is interrupted once or multiple times, and one or more components of the paper machine are maintained or replaced during these interruptions. The invention also relates to a method and system for determining a preset scheme for such interruptions, and a computer program or computer program product for performing the method.
[0002] Paper machine components, such as drying cylinders, press rolls, bearings, and especially wire mesh and / or screens (cages), require maintenance or replacement during long-term operation. This necessitates utilizing or planning for appropriate operational interruptions.
[0003] Existing technology is based on the statistical running time of each component until it fails or reaches the state requiring maintenance. It sets up periodic operation interruptions, that is, for each component, according to its statistical running time until it reaches the state requiring maintenance or its statistical service life, a corresponding operation interruption is arranged, and the maintenance or replacement of the component is completed during the operation interruption.
[0004] However, this can lead to significant performance degradation of components due to wear before operational interruption, such as a decrease in water absorption capacity. This can result in either a decline in product quality or increased production costs, such as increased energy consumption for heating the drying cylinder.
[0005] The situation becomes more complex when multiple components of a paper machine require maintenance or replacement. It is advisable to assess a component individually, especially weighing the performance degradation caused by wear against the time and material costs required for maintenance or replacement, and determine whether it should or should not be maintained or replaced at a specific time. Instead, the maintenance or replacement of that component can be performed earlier or later than the time of the operational interruption (which is earlier or later for the component as assessed individually). During the operational interruption, maintenance or replacement of one or more other components can also be performed, as this reduces the total number or duration of operational interruptions, thereby improving production efficiency.
[0006] Accordingly, if the paper machine is operated using the aforementioned scheme of periodically interrupting operation based on the statistical runtime of individual components, there is still room for improvement.
[0007] The technical problem to be solved by the present invention is to improve the operation of a paper machine and to determine an advantageous operation interruption preset scheme for the paper machine.
[0008] The technical problem is solved by a method having the features described in claim 1 or 9. Claims 10 to 12 claim protection for a system, a papermaking machine, and a computer program or computer program product for performing the method. Dependent claims relate to advantageous improvements.
[0009] According to one embodiment of the present invention, a method for determining a preset scheme for interrupting the operation of a papermaking machine includes the following steps: - supply - The predicted runtime of the paper machine's components, and / or - The estimated time required for maintenance or replacement of components of the paper machine (“Maintenance or Replacement Time”); - Predict values for one-dimensional or multi-dimensional first parameters that are directly or indirectly related to the performance and / or wear of the component at multiple future time points; - Based on the predicted parameter values, predict the values of quality assessment indicators related to the parameters for multiple future time points; - Based on the predicted values of quality assessment indicators and the provided predicted runtime and / or maintenance or replacement time, the optimizer determines the preset interruption plan for the paper machine.
[0010] In one implementation, the operation interruption preset plan includes the time points and / or durations of one or more operation interruptions of the paper machine, and / or the paper machine components to be maintained and / or replaced during (each) operation interruption. In particular, the production operation of the paper machine preferably refers to when the operation is interrupted, and / or for how long, and which components are to be maintained and / or replaced during (each) operation interruption, especially the shutdown plan and / or maintenance and replacement interval planning.
[0011] In one embodiment, the predicted runtime used in this invention is a runtime predicted or expected based on numerical models and / or experience, especially statistical data, or a runtime obtained based on numerical models and / or experience or statistical data and / or estimation, especially the (possible) maximum, minimum, or average runtime of (each) component reaching a specific state. In one embodiment, this is a component failure, a specific degree of degradation in component performance, or the risk of corresponding failures. In improved embodiments, especially for repairable or reusable components, it is the Mean Time Between Failures (MTBF), or the expected value of the runtime between two consecutive failures, and / or for (wear-out) components that cannot or do not require maintenance, it is the Mean Time to Failure (MTTF), collectively referred to as "mean time to failure".
[0012] In one implementation, the runtime interruption preset scheme is determined based on the following principles: on the one hand, optimizing the quality assessment index or, when using an optimizer, optimizing the quality assessment index; on the other hand, for example, as an additional optimization condition, prohibiting exceeding the predicted runtime, or reducing the quality assessment index when the predicted runtime is exceeded through a corresponding penalty function, so that the predicted runtime is (as far as possible) not exceeded or the extent of the exceedance is as small as possible, and / or making the cumulative total duration of multiple runtime interruptions as short as possible.
[0013] By taking into account parameters related to component performance and / or wear, an optimal balance can be found between early and late operational interruptions, minimizing production disruptions. This optimizes paper machine operation, ensuring that component performance, especially wear-related performance, is minimally degraded or not significantly degraded when interruptions are performed early. Alternatively, component maintenance or replacement time can be shortened or lengthened by advancing or delaying the preset interruption time, and / or, by determining interruption presets based on predicted maintenance or replacement times, the total cumulative short-term interruption time of the paper machine can be reduced, thereby optimizing operational efficiency.
[0014] In one embodiment, the method further includes the following steps: - Provide predicted runtime and / or predicted maintenance or replacement time for one or more other components of the paper machine; and - For multiple future time points, preferably the same time point, predict the value of at least one one-dimensional or multi-dimensional other parameters that are directly or indirectly related to the performance and / or wear of various other components, and also predict the value of the parameter of the component at the same time point; in, - Based on the predicted values of the one or more other parameters, the system also predicts values of quality assessment indicators related to the one or more other parameters for multiple future time points; and - Based on the predicted runtime and / or maintenance or replacement time of one or more other components, the optimizer determines the preset plan for the operation interruption of the paper machine. The determination principle is preferably to optimize the quality assessment index or achieve the optimal within the framework of the optimizer, and to prevent exceeding the predicted runtime of other components as an optimization constraint, or to reduce the evaluation of the quality assessment index when the predicted runtime is exceeded through a corresponding penalty function, so that the predicted runtime of each component is not exceeded (as far as possible), or the extent of the exceedance is as small as possible, and / or the total operation interruption time is as short as possible.
[0015] By considering two or more components in addition to or in parallel, it is advantageous to achieve a global consideration of the paper machine and its corresponding components for the first time in a (determined) operation interruption preset scheme, thereby significantly improving the overall operating efficiency of the paper machine.
[0016] From the perspective of quality assessment indicators, it may be more advantageous to adjust the timing of component maintenance or replacement to earlier or later than the optimal timing when evaluating the component individually. For example, it can reduce one operation interruption or shorten the total duration of operation interruption.
[0017] In one embodiment, one or more components are consumable components to be replaced during a pre-set operation interruption scenario. In a particularly advantageous improvement, these are wire meshes or wire mesh assemblies of the press and / or dryer sections of a paper machine. Additionally or alternatively, in one embodiment, one or more components are components to be maintained during a pre-set operation interruption scenario but subsequently usable. In a particularly advantageous improvement, these are rollers or roller assemblies and / or bearings or bearing assemblies of the press and / or dryer sections of a paper machine. Typically, additionally or alternatively, in one embodiment, one or more components include at least one component of the press section of a paper machine, preferably a wire mesh, and / or at least one component of the dryer section, preferably a wire mesh, and / or one or more components are screens, especially screen baskets, at least one component of the screen section, and in particular, they can be any of the aforementioned components.
[0018] Because the performance of such components changes significantly with operating time—for example, the drying and water absorption capacity of the wire mesh decreases noticeably, thus affecting the efficiency of the paper machine—or requiring higher heating power to compensate, or the screen (screen basket) may become clogged, thereby affecting product quality and / or output. Therefore, this invention is particularly applicable to the aforementioned types of components (consumable components, components requiring maintenance but still usable, components of the press / drying section, especially the wire mesh or screen section, especially the screen (screen basket), but the invention is not limited thereto).
[0019] In a particularly advantageous embodiment, the method comprises or consists of the following steps: a) Provide predicted runtime and predicted maintenance or replacement time for components of the paper machine; b) Provide the predicted runtime for at least one other component of the paper machine and, if necessary, the predicted maintenance or replacement time; c) Predict values for a first parameter related to the performance and / or wear of the component for multiple future time points; d) Predict values for at least one other parameter related to the performance and / or wear of the other components for multiple future time points; e) Based on the predicted value of the first parameter, predict the values of quality assessment indicators related to the first parameter for multiple future time points; f) Based on the predicted values of other parameters, predict the values of quality assessment indicators related to the other parameters for multiple future time points; g) Based on the predicted maintenance or replacement time of the said component and optionally based on the predicted maintenance or replacement time of the other components, predict quality assessment indicators for multiple future time points. h) Combine the predicted multiple quality assessment indicators into a comprehensive quality assessment indicator for multiple future time points; i) Based on the predicted values of the comprehensive quality assessment indicators, the optimizer is used to determine the preset interruption scheme for the paper machine.
[0020] The advantage of the modified version of the method is that, when determining the preset interruption scheme, it does not consider or optimize each component separately, but rather summarizes each individual quality assessment index into a comprehensive quality assessment index, and then optimizes this quality assessment index through an optimizer. Of course, this method is not limited to two components, but can be easily extended to multiple components, especially three, four, five or more components.
[0021] By adopting comprehensive quality evaluation indicators, the optimal operation interruption preset scheme that best suits the current machine operating state can be determined. This operation interruption preset scheme may differ significantly from the optimal operation interruption preset scheme for a single component.
[0022] Therefore, it is advantageous that the quality assessment indicators for each component be selected in a form that can be combined with each other and summarized into a comprehensive quality assessment indicator.
[0023] Equally advantageous and feasible is that these quality assessment indicators, as well as the comprehensive quality assessment indicators, are numerical values that characterize the economic cost of operating a paper machine. This economic cost can be, for example, operating costs (e.g., euros per hour or euros per ton), or the output value corresponding to the amount of paper produced per unit time (also such as euros per ton or euros per hour).
[0024] The comprehensive quality assessment index can be the sum (or weighted sum) of all individual quality assessment indicators.
[0025] By economically quantifying the impact of runtime, maintenance, or replacement time, the effects of different components can be made comparable.
[0026] Adjusting maintenance downtime beyond the optimal timing or the manufacturer's recommended maintenance intervals will have completely different effects on different components of the paper machine, thus having entirely different impacts on quality assessment indicators. The following example illustrates this: Example 1: Press felt component If the press felt continues to operate beyond its optimal state, the paper machine can still continue production for a period of time. However, due to decreased dewatering performance, the "dry solids content after pressing" parameter will decrease, resulting in a higher moisture content when the paper leaves the press section. Therefore, more energy needs to be consumed in the drying section to achieve the desired final dry solids content. The corresponding economic impact, namely the increase in steam consumption (tons / hour) and the resulting costs, will be included in the calculation of quality assessment indicators. However, if the press felt continues to be used beyond its maximum operating time, the risk of felt breakage and / or the risk of more paper becoming unsellable due to quality defects will increase significantly. This risk can also be factored into the cost of scrap or the failure cost of unexpected downtime for replacement due to felt breakage and included in the quality assessment indicators.
[0027] The maintenance downtime required to replace felt can also be quantified economically, for example, by calculating the typical downtime and the resulting loss of production.
[0028] Similar analysis applies to other types of netting, such as shaped netting and dry netting.
[0029] Example 2: Screen basket for the slurry preparation section
[0030] Screen baskets are typically replaced at fixed intervals. Similar to wire mesh, screen baskets can continue operating for a period after exceeding their optimal state, but this usually affects the "slag discharge rate" parameter. This results in a higher proportion of fiber pulp being discharged as "waste," leading to an increase in fiber raw material consumption per ton of paper. The increased fiber cost can also be factored into the quality assessment indicators corresponding to screen basket replacement.
[0031] Similarly, the sieve basket also has a maximum operating time, beyond which the risk of failure increases disproportionately.
[0032] The maintenance downtime required to replace the screen basket can also be quantified economically, for example, by calculating the typical downtime and the resulting production loss.
[0033] Example 3: Bearings of rotating components
[0034] For bearings used in the rollers of the pressing or forming sections, exceeding the optimal replacement time usually does not directly affect production costs. However, the risk of failure will continue to rise, leading to prolonged equipment downtime and high maintenance costs, resulting in significant losses for operators. The parameter of "failure risk" can also be converted into a quality assessment indicator, for example, by saving a failure risk escalation curve and multiplying it by the predicted or prescribed costs of failure handling.
[0035] The maintenance downtime required to replace bearings can also be quantified economically, for example, by calculating the typical downtime duration and the resulting production losses.
[0036] These three examples alone demonstrate the high versatility of the method proposed in this invention. Furthermore, through economic quantification, completely different types of components and their corresponding operating parameters can be compared and mutually weighed.
[0037] The components considered can all come from the same part of the paper machine, or they can come from different parts, such as the preparation section, headbox, forming section, press section, drying section, as well as the winding section or coating section.
[0038] A particular advantage lies in the fact that multiple components originate from interconnected parts. If these parts were independent, such as a roll cutter or an offline coater, the advantages of this method would be relatively small, as these devices could be shut down and maintained independently of the main paper machine. However, for parts like the press and dry sections, or the preparation and headbox sections, they are directly coupled in the production process. Therefore, for components in interconnected parts, the benefits of optimized, coordinated operational interruption preset schemes are particularly significant.
[0039] In one implementation, the quality assessment index is predicted based on one or more parameters related to the performance and / or wear of paper machine components, the performance function of the corresponding component and / or replacement and maintenance costs, and / or the paper machine's output and / or processing speed, and / or the energy consumption of at least one component of the paper machine or the entire paper machine in an improvement scheme. These parameters can be particularly advantageously optimized by considering them when determining operational interruption preset schemes.
[0040] In one implementation, the values of one or more parameters are predicted based on parameter values for one or more past time points. This allows for parameter prediction in a particularly reliable, simple, and accurate manner.
[0041] In one embodiment, one or more quantities, particularly one or more parameters, used in this invention are assigned values through cost functions during the optimization process. In the improved scheme, the cost functions can be associated with corresponding lists. This, in particular, enables advantageous quantitative scaling and scalability. For example, duration, material consumption, energy consumption, output, or production speed can all be advantageously weighted and mutually balanced in quality assessment indicators through corresponding cost functions.
[0042] According to one embodiment of the present invention, a method for operating a paper machine includes steps preferably performed in multiple cycles (in the following order): - Paper machine production operation; - Production operations were interrupted; - To maintain and / or replace at least one component of the paper machine during operational interruptions; and - The paper machine resumes production after the interruption ends; In the improved embodiment, the method according to any one of the preceding claims specifies one or more time points and / or one or more durations of operational interruption and / or components to be maintained and / or replaced (“operational interruption preset scheme”). Subsequent production runs can, in particular, continue the previous production run. Similarly, subsequent production runs can also be of a different type than the previous one. Therefore, in the definition of this invention, the period of no production between two different types of production runs of the paper machine also constitutes an (machine) operational interruption.
[0043] According to one embodiment of the present invention, a system, particularly hardware and / or software, particularly a program, technically performs the aforementioned method, and / or the system has: - Devices for providing predicted runtime of components of a paper machine and one or more other components in an improvement scheme and / or devices for providing predicted maintenance or replacement time of one or more components of a paper machine; - A device for predicting the value of a first parameter related to the performance and / or wear of the component for multiple future time points and the values of other parameters related to the performance and / or wear of other components (respectively) in an improved scheme; - A device for predicting values of quality assessment metrics related to a first parameter and, if necessary, one or more other parameters, for multiple future time points based on predicted parameter values; - Devices, especially the corresponding optimizers, used to determine preset plans for paper machine operation interruptions based on predicted values of quality assessment indicators and the provided predicted runtime and / or maintenance or replacement duration using an optimizer.
[0044] According to one embodiment of the present invention, a papermaking machine apparatus has one or more papermaking machines and a system for determining a preset scheme for interrupting the operation of the papermaking machines and / or operating the papermaking machines according to the aforementioned method.
[0045] The device under the present invention can be designed in hardware and / or software form, particularly having a digital processing unit, particularly a microprocessor unit (CPU), graphics processor (GPU), etc., and / or one or more programs or program modules, preferably connected to a memory and / or bus system for data or signal connections. The processing unit can be designed to process instructions embedded in the form of a program stored in the memory system, and to issue input signals for detecting the data bus and / or output signals on the data bus. The memory system can have one or more, particularly different, memory media, particularly optical, magnetic hard disks, and / or other non-volatile media. The program can be obtained such that it reflects or implements the methods described herein, causing the processing unit to perform the steps of the method, thereby particularly determining a preset interruption scheme for one or more paper machines, and / or operating the paper machine. In one embodiment, the computer program product can be, in particular, a computer-readable non-volatile storage medium for storing a program or instructions or storing a corresponding program or instructions. In one embodiment, when a system, particularly a computer, or an apparatus consisting of multiple computers executes the program or instructions, it causes the system, particularly the computer, to perform the method or one or more steps thereof, or to configure the program or instructions for this purpose.
[0046] In one embodiment, one or more, especially all, steps of the method may be implemented wholly or partially by a computer, or one or more, especially all, steps of the method may be executed wholly or partially automatically, especially by the system and its devices. In one embodiment, the optimizer includes an optimization algorithm, and / or is run on a computer, executed by a computer, or implemented with computer assistance.
[0047] Further advantages and features are described in the dependent claims and embodiments. Partially schematically illustrated in the accompanying drawings: Figure 1 A system according to an embodiment of the present invention for determining a preset plan for interrupting the operation of a paper machine and operating the paper machine; Figure 2 A method for operating a paper machine according to an embodiment of the present invention includes determining a preset plan for interrupting the operation of the paper machine.
[0048] Figure 1 A system in the form of a correspondingly programmed computer 2 is shown according to an embodiment of the present invention, the system being used to determine a preset interruption scheme for the operation of a paper machine 1 and to operate the paper machine 1.
[0049] Figure 2 A method for operating a paper machine according to an embodiment of the present invention is shown, the method comprising determining a preset scheme for interrupting the operation of the paper machine.
[0050] Before or during the production operation of the paper machine, it is necessary to determine the timing and / or duration of one or more future operation interruptions, as well as the paper machine components to be maintained and / or replaced (“operation interruption preset plan”).
[0051] Therefore, in step S10, predicted runtime, preferably mean time to failure, especially MTBF or MTTF, for multiple components of the paper machine are provided, and / or predicted maintenance or replacement time, such as MTBF, and / or predicted replacement time for one or more wires in the press section and / or one or more wires in the dry section and / or one or more screen baskets in the screen section of the paper machine are provided.
[0052] In step S20, for multiple future time points t k t k+1 ..., one-dimensional or multi-dimensional parameters x that are directly or indirectly related to the performance and / or wear of one of the components. i The value.
[0053] For example, the performance of wire mesh will continuously degrade over time, and may need to be compensated for by increasing heating power and / or reducing the operating speed of the paper machine. Therefore, this parameter of the wire mesh can characterize the increase in heating power caused by the degradation of the corresponding wire mesh performance, or the reduction in production speed to compensate for the degradation of wire mesh performance. If necessary, it can also be converted into the corresponding cost for better quantification. The same applies to screen baskets.
[0054] In step S30, for a future time point t k t k+1 ..., predict the values of quality assessment indicators related to these parameters, such as the weighted sum of the corresponding (converted) increase in heating power and / or decrease in production speed if necessary.
[0055] In step S40, the optimization algorithm or the optimizer running on the computer determines the time points and / or durations of one or more future operation interruptions, as well as the components to be maintained and / or replaced at each operation interruption, based on the predicted values of the quality assessment indicators and the predicted runtime and / or maintenance or replacement time of the provided components. Preferably, this is done so that, on the one hand, the increased heating costs and / or reduced production speed to compensate for the decline in the performance of the netting are minimized, and / or the total duration of the operation interruption is minimized, and on the other hand, it does not exceed the MTBF or MTTF of each component, and in particular, the corresponding maintenance or replacement time is taken into consideration.
[0056] In a highly simplified example, the average lifespan of the first netting is x1 hours, the average lifespan of the second netting is x2 hours, x2 > x1, replacing the first netting takes y1 hours, replacing the second takes y2 hours, y2 > y1, and as usage time increases, the performance degradation of the first netting causes the quality assessment index to decrease by y1 hours. 1. Furthermore, the performance degradation of the second netting will cause the quality assessment index to decrease by 1 hour. 2. For example, through optimization, the following optimal result can be obtained: Replacing the first and second netting blankets in the same operational interruption for a duration of y2, with the replacement time being at most or less than x1 hours from the last replacement, will yield better quality assessment indicators. Although the second netting blanket has not yet reached its average lifespan, and replacing the first netting blanket alone requires only a shorter operational interruption duration y1, from a global perspective, if the first and second netting blankets are replaced separately in two separate operational interruptions, the performance degradation of the second netting blanket and the cumulative total duration of all operational interruptions should be taken into account. Similarly, from the perspective of quality assessment indicators, one can also choose to tolerate the performance degradation of the second netting blanket and postpone its replacement until it is replaced together with the third netting blanket, as long as this yields better quality assessment indicators, especially since the replacement duration y1 of the first netting blanket is shorter. This very simple example demonstrates the value of determining the operation interruption preset scheme according to the present invention. Because there are complex relationships between different components, especially the predicted running time, maintenance or replacement time, and performance / wear of each component, the operation of the paper machine can be significantly optimized based on (comprehensive) quality assessment indicators. This is because the performance degradation of individual components due to extended running time compared to frequent maintenance or premature replacement is taken into account, thereby achieving optimal maintenance and replacement of different components.
[0057] In step S50, the paper machine's production operation is continued, either implemented or in an improved plan. The production operation is interrupted at the time point determined in step S40 for a determined duration. Figure 2 Step S60), and perform maintenance or replacement on the corresponding parts of the paper machine. Figure 2 Step S70). Afterwards, another production run of the paper machine is implemented, or the previous production run of the paper machine is continued in the improvement plan. Figure 2 Step S80).
[0058] In this disclosure, "having X" is not an exhaustive list, but rather an abbreviation for "having at least X," and also includes the meaning of "having two or more X" and "having Y in addition to X." Although exemplary embodiments have been described above, it should be noted that the present invention can have various variations.
[0059] In particular, as mentioned earlier, the (new) operation interruption preset scheme can also be determined during production operation, thereby making predictions particularly advantageous based on parameter values at previous time points.
[0060] Furthermore, it should be noted that the exemplary embodiments are merely examples and do not limit the scope, application, or structure of the invention in any way. More precisely, the foregoing description provides guidance to those skilled in the art for implementing at least one exemplary embodiment, wherein various modifications can be made to the function and arrangement of the foregoing components, in particular, without departing from the scope of protection set forth in the claims.
[0061] List of reference numerals
[0062] 1. Paper machine
[0063] 2 Computers
Claims
1. A method for determining a preset scheme for the operation interruption of a paper machine (1), wherein, The method comprises the following steps: - Provide predicted runtime and / or predicted maintenance or replacement time for components of the (S10) paper machine; - Values of a first parameter related to the performance and / or wear of the component for multiple future time point predictions (S20); - Based on the predicted parameter values, predict (S30) the values of quality assessment indicators related to the parameters for multiple future time points; - Based on the predicted values of quality assessment indicators and the provided predicted runtime and / or maintenance or replacement time, the optimizer determines (S40) the preset operation interruption plan for the paper machine.
2. The method according to claim 1, characterized in that, The method also includes the following steps: - Provide (S10) the predicted runtime and / or predicted maintenance or replacement time for at least one other component of the paper machine; and - The value of at least one other parameter related to the performance and / or wear of the other components for multiple future time point predictions (S20); in, - Based on the predicted values of the other parameters, the system also predicts values of quality assessment indicators related to the other parameters for multiple future time points; and - Based on the predicted runtime and / or maintenance or replacement time of other components provided, the optimizer determines the preset interruption scheme for the paper machine.
3. A method for determining a preset scheme for the operation interruption of a paper machine (1), wherein, The method comprises the following steps: Provide (S10) the predicted runtime and predicted maintenance or replacement time for the components of the paper machine; Provide (S10a) the predicted runtime of at least one other component of the paper machine and, if necessary, the predicted maintenance or replacement time; Values of a first parameter related to the performance and / or wear of the component for multiple future time point predictions (S20); The value of at least one other parameter related to the performance and / or wear of the other components for multiple future time point predictions (S20a); Based on the predicted first parameter value, predict (S30) the values of quality assessment indicators related to the first parameter for multiple future time points; Based on the predicted values of other parameters, predict (S30a) the values of quality assessment indicators related to the other parameters for multiple future time points; Based on the predicted maintenance or replacement time of the component described in (S35) and optionally based on the predicted maintenance or replacement time of other components described in (S35a), quality assessment indicators are predicted for multiple future time points. The predicted multiple quality assessment indicators (S30, S30a, S35, S35a) are combined into a comprehensive quality assessment indicator for multiple future time points. Based on the predicted values of the comprehensive quality assessment indicators, the optimizer determines (S40) the preset plan for the interruption of the paper machine's operation.
4. The method according to any one of the preceding claims, characterized in that, At least one quality assessment indicator, especially all quality assessment indicators and the comprehensive quality assessment indicator, is a numerical value that characterizes the economic cost of operating a paper machine.
5. The method according to any one of the preceding claims, characterized in that, At least one of the components is a worn component to be replaced when the operation interruption preset scheme is executed, and / or at least one of the components is a component to be maintained when the operation interruption preset scheme is executed and will continue to be used thereafter.
6. The method according to any one of the preceding claims, characterized in that, The component and other components come from different parts of the paper machine.
7. The method according to any one of the preceding claims, characterized in that, At least one parameter related to the performance and / or wear of a component of the paper machine is related to the component's performance function and / or replacement and maintenance costs and / or the paper machine's output and / or processing speed and / or the energy consumption of at least one component of the paper machine.
8. The method according to any one of the preceding claims, characterized in that, Predict the value of at least one parameter based on parameter values for one or more past time points.
9. A method of operating a paper machine (1), comprising steps preferably performed in multiple cycles: - Paper machine production operation (S50); - Production operation interrupted (S60); - To maintain and / or replace at least one component of the paper machine during an operational interruption (S70); and - The paper machine resumes production operation after the interruption ends (S80); in, The method according to any one of the preceding claims specifies the time point and / or duration of the operation interruption and / or the components to be maintained and / or replaced.
10. A system (2) for determining a preset interruption scheme for a paper machine (1) and / or operating the paper machine (1), said system being configured to perform the method according to any one of the preceding claims, and / or said system having: - Devices used to provide predicted runtime and / or predicted maintenance or replacement time for components of a papermaking machine; - A device for predicting the value of a first parameter related to the performance and / or wear of the component at multiple future time points; - A device for predicting values of quality assessment metrics related to the parameters for multiple future time points based on predicted parameter values; - A device used by an optimizer to determine preset plans for interrupting the operation of a paper machine based on predicted values of quality assessment indicators and the provided predicted runtime and / or maintenance or replacement time.
11. A papermaking machine apparatus comprising at least one papermaking machine (1) and a system (2) for determining a preset scheme for interrupting operation of the papermaking machine and / or operating the papermaking machine according to any one of the preceding claims.
12. A computer program or computer program product, wherein, The computer program or computer program product includes instructions, in particular stored on a computer-readable and / or non-volatile storage medium, which, when executed by one or more computers or a system or papermaking machine according to any one of the preceding claims, cause one or more computers or systems or papermaking machine to perform the method according to any one of the preceding claims.