Full-life-cycle pre-pressing production optimization method for paper machine blanket

Abstract

The invention discloses a full-life-cycle pre-pressing production optimization method and system for a papermaking machine blanket, and belongs to the technical field of papermaking machinery and intelligent manufacturing. According to the method, the operation cycle of the blanket is divided into an adaptation period, a normal period and a final period, and performance optimization is achieved by regulating and controlling key parameters in stages, specifically, within initial 24-36 hours, the carrier roller linear pressure (15-22 kN / m) and the vacuum degree (-40 kPa to-60 kPa) are increased, cleaning is strengthened, a penetrating agent and a lubricating agent with the specific concentration are added, and rapid activation is achieved; after entering a normal period, controlling the middle height (0.1-0.3 mm) and the parameter fluctuation range of the carrier roller, using a composite additive (a penetrant, an antistatic agent and a bactericide in a specific ratio of 1: 0.8: 0.5), and optimizing a paper pulp fiber structure; in the whole period, the running resistance, the dehydration efficiency and the body paper evenness are monitored through an online system, and graded early warning and replacement prompts are set. The system comprises a parameter regulation and control module, an auxiliary adding module and an online monitoring module. According to the scheme, the adaptation period is effectively shortened, the service life is prolonged, the production stability is improved, and remarkable economic and technical benefits are achieved.

Description

Technical Field

[0001] This invention relates to the field of papermaking technology, and in particular to a pre-pressing production method and system for papermaking machine felts, which is especially suitable for parameter control and performance optimization of felts throughout their entire life cycle in the production of household paper. Background Technology

[0002] In the production of tissue paper, paper machine felts are a key consumable, directly affecting the quality stability of the base paper and the operating efficiency of the production line. After being installed on the machine, the felts undergo three stages: adaptation, normal operation, and final stage. Changes in their performance significantly impact dewatering efficiency, paper uniformity, and machine speed control. Currently, the industry generally employs experience-based parameter control methods, maintaining the felt's operating status by adjusting basic parameters such as idler roller line pressure, vacuum level, and cleaning frequency, supplemented by conventional chemical cleaning agents for maintenance. Some advanced companies have attempted to introduce online monitoring methods to track felt resistance or air permeability, but these are mostly limited to monitoring single indicators and have not yet formed a systematic control scheme covering the entire life cycle.

[0003] In existing technologies, the adaptation period for felts typically lasts 3-5 days, leading to unstable paper quality and significant raw material waste in the initial startup phase. The normal operating cycle accounts for a low percentage, with an overall lifespan generally around 70 days, and performance deteriorates rapidly towards the end, making timely replacement difficult. These problems stem from a lack of in-depth research into the coupling relationships of multiple parameters, simplistic additive formulations that fail to balance permeability and abrasion resistance, and the absence of high-frequency, multi-dimensional real-time monitoring mechanisms, resulting in delayed adjustments and severely impacting production efficiency and product consistency. Therefore, a comprehensive optimization method is urgently needed to achieve rapid felt activation, stable operation, and intelligent early warning systems. Summary of the Invention

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a pre-pressing production method and system for paper machine felts, which systematically solves the problems of long adaptability and short life cycle of felts through staged precise parameter control, innovative additive formulation, and intelligent online monitoring.

[0005] A method for optimizing the pre-compression production of paper machine felts throughout their entire lifecycle according to a first aspect of the present invention includes the following sequential steps: (1) Rapid activation steps during the adaptation period: During the initial 24-36 hours of the felt machine operation, control the operating parameters of the paper machine as follows: control the linear pressure of the idler roller within the range of 15-22 kN / m; control the vacuum degree of the vacuum chamber within the range of -40~-60 kPa; control the felt cleaning pressure within the range of 0.8-1.2 MPa, and control the cleaning frequency within every 10-15 minutes; add chemical additives to the system, wherein the concentration of penetrant is controlled within 0.1-0.3%, and the concentration of lubricant is controlled within 0.08-0.2%.

[0006] (2) Stable operation steps during normal period: After the blanket completes the adaptation period, it enters the normal operation stage. During this stage: control the height of the idler roller within the range of 0.1-0.3 mm, control the vacuum fluctuation within ±2 kPa, and control the idler roller linear pressure fluctuation within ±0.5 kN / m; use composite additives, which include penetrant, antistatic agent and bactericide in a ratio of 1:0.8:0.5, and control the total concentration of the composite additives within 0.3-0.5%; control the fine fiber content in the pulp used for papermaking within the range of 12-18%, and achieve a cleanliness of 98-99%.

[0007] (3) End-of-life monitoring and early warning steps: Throughout the entire life cycle of the blanket operation, online monitoring is continuously performed, and early warning and decision-making are made based on the following thresholds: real-time monitoring of blanket operation resistance, dewatering efficiency and uniformity of the produced base paper; when the blanket operation resistance increases by 30%, the dewatering efficiency decreases by 25%, or the uniformity deviation of the base paper reaches ±3%, the system issues an early warning signal; when the blanket operation resistance increases by 50%, the dewatering efficiency decreases by 40%, or the uniformity deviation of the base paper reaches ±5%, the system prompts to replace the blanket.

[0008] According to an embodiment of the present invention, a method for optimizing the pre-compression production of paper machine felts throughout their entire lifecycle has at least the following beneficial effects: The present invention systematically divides the felt lifecycle into three stages: adaptation, normal, and final stages, and sets differentiated collaborative parameter control strategies for each stage, thereby achieving precise control of felt performance. Specifically, during the adaptation stage, by optimizing idler roller line pressure, vacuum degree, cleaning parameters, and additive concentration, the time required can be significantly shortened from the traditional 3-5 days to 24-36 hours, rapidly activating felt performance. During the normal stage, by stabilizing equipment parameters, using specific proportions of composite additives, and controlling pulp fiber quality, the decay of felt performance is significantly delayed, extending its lifecycle from approximately 70 days to 89 days, while ensuring stable raw paper quality. During the final stage, by online monitoring of multiple parameters such as operating resistance, dewatering efficiency, and raw paper uniformity, and by setting graded early warning thresholds, scientific decision-making and early warning for felt replacement are achieved, avoiding unplanned downtime and quality risks. Ultimately, this method effectively reduces production costs while comprehensively improving production efficiency, product quality, and the level of production line intelligence, demonstrating significant economic benefits and application promotion value.

[0009] According to some embodiments of the present invention, in step (2), by optimizing the high curve of the idler roller and establishing the pulp fiber control process, the air permeability decay rate of the felt is not greater than 2% / week, the thickness decay rate is not greater than 1% / week, and the abrasion resistance is not less than 8000 times.

[0010] According to some embodiments of the present invention, step (3) is implemented by an online data acquisition and early warning system, which acquires data at a frequency of not less than once per minute and issues an early warning signal within 5 minutes after the monitoring data triggers the early warning threshold.

[0011] According to some embodiments of the present invention, the online data acquisition and early warning system integrates a visual monitoring unit for real-time monitoring of the physical damage to the blanket.

[0012] A paper machine felt pre-compression production system according to a second aspect of the present invention, for implementing any of the above methods, includes: The parameter control module is used to adjust the roller line pressure, vacuum degree, cleaning pressure and frequency in steps (1) and (2); An additive addition module is used to perform the ratio and concentration control of chemical additives and composite additives in steps (1) and (2); The online monitoring module is used to collect and provide real-time early warning of data on blanket running resistance, dewatering efficiency, and paper uniformity in step (3).

[0013] According to an embodiment of the present invention, a paper machine felt pre-pressing production system has at least the following beneficial effects: The system, through the coordinated operation of a parameter control module, an additive addition module, and an online monitoring module, constructs a complete intelligent management and control system for the entire lifecycle of the felt. Specifically, the parameter control module ensures the precise execution and stable control of various process parameters during the adaptation and normal operation periods, providing an equipment foundation for rapid felt activation and long-term stable operation. The additive addition module achieves precise proportioning and concentration control of chemical additives and composite additives, ensuring the optimization and delayed degradation of felt performance from a chemical perspective. The online monitoring module, through real-time acquisition and analysis of operating resistance, dewatering efficiency, and paper uniformity, combined with a multi-level early warning mechanism, achieves full-process perception and scientific decision support for felt status, effectively avoiding quality fluctuations and unplanned downtime caused by felt performance degradation. Through the organic integration of various modules, the entire system translates the optimization method into an executable automated solution, significantly improving the level of production intelligence, operational stability, and economic benefits.

[0014] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Detailed Implementation

[0015] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0016] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution. Example

[0017] As a crucial forming and dewatering component in the papermaking process, the performance of paper machine felts directly impacts the quality stability of the base paper, production efficiency, and operating costs. In existing technologies, paper machine felts generally suffer from an excessively long adaptation period, typically requiring 3 to 5 days to reach stable operation. During this period, the paper machine speed is limited, paper uniformity is poor, and the breakage rate is high, severely affecting the overall efficiency of the production line. Furthermore, during normal operation, due to the lack of systematic parameter coordination control, felts are prone to clogging, uneven compaction, and static electricity buildup, leading to a rapid decline in dewatering efficiency and a service life generally limited to around 70 days. Towards the end of the service life, the lack of effective online monitoring methods makes it impossible to promptly identify performance degradation trends, often resulting in replacement only when severe quality fluctuations or sudden damage occur, causing unplanned downtime and raw material waste. These problems collectively hinder the progress of tissue paper manufacturers towards high-quality, high-efficiency, and low-cost production.

[0018] A method for optimizing the pre-compression production of paper machine felts throughout their entire lifecycle includes the following sequential steps: Step 1: Rapid Activation During the Adaptation Period During the initial 24-36 hours of operation of the felt on the paper machine, the operating parameters of the paper machine should be controlled as follows: the linear pressure of the idler rollers should be controlled within the range of 15-22 kN / m; the vacuum degree of the vacuum chamber should be controlled within the range of -40~-60 kPa; the felt cleaning pressure should be controlled within the range of 0.8-1.2 MPa, and the cleaning frequency should be controlled once every 10-15 minutes; chemical additives should be added to the system, with the concentration of penetrant controlled within 0.1-0.3% and the concentration of lubricant controlled within 0.08-0.2%.

[0019] The phrase "within the initial 24-36 hours of blanket operation" refers to the time window from the installation of the new blanket and its participation in the wet-end forming process. This period is crucial for the transformation of the blanket structure from a loose to a dense and stable state. Applying specific combinations of process parameters during this stage helps accelerate the matching process between the fiber web and the blanket surface and promotes the uniform compaction of the internal pore structure. Optionally, this time range can be adaptively adjusted according to different basis weights, thicknesses, or materials (such as polyester single-layer, double-layer composite, etc.). For example, a 24-hour upper limit can be used for high-permeability blankets, while for low-permeability, high-density blankets, it can be extended to 36 hours to ensure full activation.

[0020] The linear pressure of the idler roller is controlled within the range of 15-22 kN / m, representing the pressure value per unit length of the contact area between the blanket and the idler roller. Higher linear pressure helps to accelerate the alignment and micro-compaction of fibers on the blanket surface, preventing uneven moisture migration due to excessively large gaps in the initial stage. When the linear pressure is below 15 kN / m, the compaction effect is insufficient, and the adaptation period is prolonged; exceeding 22 kN / m may lead to localized over-compression, affecting subsequent dewatering capacity. In an optional embodiment, the linear pressure can be adjusted in a gradient manner, for example, set at 15-18 kN / m for the first 12 hours, and then gradually increased to 20-22 kN / m to achieve gradual activation.

[0021] The vacuum level of the vacuum chamber is controlled within the range of -40 to -60 kPa, referring to the negative pressure intensity generated by the vacuum suction device. A stronger vacuum environment can enhance the adhesion of the felt to the wet paper web, increase the dewatering rate, and help remove fine fibers and fillers that tend to accumulate in the initial stage. If the vacuum is too low (e.g., >-40 kPa), the dewatering power will be insufficient; if it is too high (e.g., <-60 kPa), it may cause excessive stretching and deformation of the felt or a significant increase in energy consumption. In practical applications, precise zone control can be achieved through a multi-segment independently adjustable vacuum chamber structure, which is especially suitable for wide-width paper machines.

[0022] The blanket cleaning pressure is controlled within the range of 0.8-1.2 MPa, referring to the water jet pressure used by the spray system to clean dirt from the blanket surface. Compared to the traditional cleaning pressure of 0.6-1.0 MPa, this solution increases the cleaning kinetic energy, more effectively flushing away fine particles embedded in the blanket surface. Combined with a cleaning frequency controlled every 10-15 minutes, this forms a high-frequency, high-pressure cleaning strategy, preventing contaminants from accumulating and forming hard clumps, and maintaining the blanket's permeability. In a variant, the cleaning frequency can be dynamically adjusted based on the blanket's operating speed; for example, a 10-minute interval is used when the speed exceeds 1200 m / min, and adjusted to once every 15 minutes when the speed is below this value, balancing cleaning effectiveness and water consumption.

[0023] Chemical additives are added to the system, with the penetrant concentration controlled at 0.1-0.3% and the lubricant concentration controlled at 0.08-0.2%. The penetrant can be selected from alkylphenol polyoxyethylene ethers (APEO-free), fatty alcohol polyoxyethylene ethers, or sulfonate-type surfactants. Its main function is to reduce the interfacial tension of the liquid, promote the rapid penetration of the aqueous phase into the blanket structure, and reduce the amount of retained water. The lubricant is preferably polyethylene glycol or silicone oil emulsion, which can form a protective film between the blanket and the metal parts, reduce the coefficient of friction, and prevent mechanical wear. The synergistic effect of the two additives improves both the mass transfer efficiency inside the blanket and enhances operational stability. In an alternative embodiment, the lubricant can be replaced with a nano-silica dispersion with lubricating function to further improve wear resistance.

[0024] The aforementioned parameters are not set in isolation, but rather work together through a multi-parameter coupling mechanism: appropriately increased roller linear pressure and vacuum level synergistically enhance the dewatering driving force, while high-pressure, high-frequency cleaning ensures the continuous unobstructed flow of the dewatering channel; the introduction of chemical auxiliaries optimizes the wetting and slippage characteristics of the blanket at the material interface behavior level. The combination of these three factors significantly shortens the time required for blanket structural remodeling, reducing the adaptation process, which originally took several days, to within 24-36 hours to achieve stable operation.

[0025] Step Two: Stable Operation During Normal Period After the blanket has completed its adaptation period, it enters the normal operation phase. During this phase: the height of the idler roller is controlled within the range of 0.1-0.3mm; the vacuum fluctuation is controlled within ±2 kPa; and the linear pressure fluctuation of the idler roller is controlled within ±0.5 kN / m. Composite additives are used, which include penetrants, antistatic agents, and bactericides in a ratio of 1:0.8:0.5, with the total concentration of the composite additives controlled at 0.3-0.5%. The fine fiber content in the pulp used for papermaking is controlled within the range of 12-18%, and the cleanliness reaches 98-99%.

[0026] The phrase "controlling the crown height of the idler roll within the range of 0.1-0.3 mm" refers to the amount of protrusion (crown height) of the roll's center diameter relative to its ends. A properly designed crown height compensates for elastic deformation after the paper machine is loaded, ensuring uniform stress on the felt across the entire width and preventing edge leakage or excessive compaction in the center. A crown height below 0.1 mm may lead to insufficient dewatering in the center, while a crown height above 0.3 mm can easily cause excessive pressure damage to the edges. Optionally, the crown height value should be customized based on the felt width, machine speed, and paper type; for example, a crown height curve of 0.2 mm is recommended for 4.5-meter wide machines.

[0027] Vacuum fluctuations are controlled within ±2 kPa, emphasizing the dynamic stability of the system rather than its static setpoint. A closed-loop feedback control system monitors pressure changes within the vacuum chamber in real time and adjusts the vacuum pump unit's start / stop or frequency converter output accordingly, ensuring the fluctuation range remains within acceptable limits. Similarly, idler roller linear pressure fluctuations are controlled within ±0.5 kN / m, relying on the precise adjustment capabilities of the hydraulic or pneumatic pressurization system to prevent transient overpressure or underpressure caused by external disturbances (such as paper web breakage or transmission impact), thus maintaining the continuity and consistency of the felt operation.

[0028] A composite additive is used, comprising a penetrant, an antistatic agent, and a bactericide in a ratio of 1:0.8:0.5, with the total concentration controlled at 0.3-0.5%. This formulation, validated through orthogonal experiments, exhibits multiple integrated advantages: the penetrant continues to improve wetting performance; the antistatic agent (such as quaternary ammonium salts or conductive polymers) effectively eliminates the accumulation of static charge during high-speed operation, preventing dust adsorption and fire risks; and the bactericide (such as isothiazolinones) inhibits microbial growth, preventing biofilm from clogging the blanket pores. The three components, when combined in the specified ratio, demonstrate good compatibility and synergistic effects. In another embodiment, the type of bactericide can be adjusted according to water hardness; for example, a hard-water-resistant bactericide can be selected in high-calcium areas to maintain efficacy.

[0029] The fine fiber content in the pulp used for papermaking is controlled within the range of 12-18%, achieving a cleanliness of 98-99%. Excessive fine fibers increase the risk of felt clogging, while insufficient fibers affect paper strength and uniformity. Through screening, purification, and grading processes, the pulp composition is precisely controlled to maintain its optimal range. Cleanliness refers to the proportion of impurities (such as sand and adhesives) per unit volume of pulp, achieved through high-efficiency descaling devices and screening drums. In an optional solution, an online turbidity sensor can be introduced to continuously monitor pulp cleanliness and link with the cleaning system for on-demand cleaning.

[0030] The aforementioned parameter system constructs a highly stable operating environment: mechanical parameters (medium to high, with pressure fluctuations) ensure the consistency of physical contact, chemical additives maintain the cleanliness and functional activity of the blanket's surface and internal microenvironment, and raw material quality control reduces contamination load from the source. These four factors work synergistically to significantly slow down the blanket's performance degradation process and extend its normal operating cycle.

[0031] Step 3: End-stage monitoring and early warning procedures Throughout the entire lifecycle of the blanket operation, continuous online monitoring is performed, and warnings and decisions are made based on the following thresholds: real-time monitoring of blanket running resistance, dewatering efficiency, and uniformity of the produced base paper; when the blanket running resistance increases by 30%, the dewatering efficiency decreases by 25%, or the base paper uniformity deviation reaches ±3%, the system issues a warning signal; when the blanket running resistance increases by 50%, the dewatering efficiency decreases by 40%, or the base paper uniformity deviation reaches ±5%, the system prompts to replace the blanket.

[0032] The phrase "throughout the entire lifecycle of the blanket operation" indicates that the monitoring mechanism spans the entire service life, not just the final stage, but is primarily used to identify performance degradation trends. Operating resistance can be indirectly obtained by measuring drive motor current or tension sensor data, reflecting changes in the internal flow resistance of the blanket; dewatering efficiency is calculated by comparing the difference in dryness before and after the vacuum chamber or by the amount of water drained; and paper uniformity is determined using an infrared scanner or a multi-point basis weight detection device to measure the standard deviation of the basis weight distribution.

[0033] A two-level response mechanism is set up: The first level is an "early warning signal," triggered by a 30% increase in operating resistance, a 25% decrease in dewatering efficiency, or a paper uniformity deviation reaching ±3%. At this time, the system automatically records the abnormal data and notifies the operator to check the felt condition, potentially taking intervention measures such as enhanced cleaning, adjusting vacuum distribution, or temporarily reducing speed. The second level is a "replacement reminder." When any indicator deteriorates to a 50% increase in resistance, a 40% decrease in dewatering efficiency, or a uniformity deviation reaching ±5%, the system determines that the felt is nearing the end of its lifespan and recommends stopping the machine for replacement to avoid sudden malfunctions affecting product quality.

[0034] This tiered early warning mechanism shifts the focus from passive maintenance to proactive prediction. Through multi-dimensional data fusion analysis, it avoids misjudgments based on single indicators, improving decision-making reliability. In modified implementations, machine learning models can be introduced to model historical data, dynamically optimizing threshold settings to adapt to individual differences under varying operating conditions.

[0035] Through the above-described steps, this application achieves refined management of the entire lifecycle of paper machine felts. During the adaptation period, by improving key process parameters and supplementing with specialized chemical additives, the compaction and functional activation of the felt structure are accelerated, shortening the traditional 3-5 day adaptation cycle to 24-36 hours. During the normal operation period, by precisely controlling the range of mechanical fluctuations, using multifunctional composite additives, and optimizing pulp quality, a stable operating environment is constructed, effectively slowing down felt performance degradation and extending overall service life. In the final stage, through multi-parameter online monitoring and a graded early warning mechanism, dynamic perception and scientific decision-making regarding felt health status are achieved, avoiding unplanned downtime. These technical features are interconnected and synergistic, jointly solving the technical challenges of slow felt adaptation, short lifespan, and large maintenance blind spots in existing technologies, significantly improving production continuity, consistency of base paper quality, and operational economy. This method can be widely applied to various tissue paper, cultural paper, and packaging paper production lines, and is particularly suitable for the high-performance felt management needs in medium- and high-speed paper machines (speed ≥ 1000 m / min). Example

[0036] Based on the above embodiments, this embodiment further provides: By optimizing the high-temperature curve of the idler roller and establishing a pulp fiber control process, the air permeability decay rate of the felt is no more than 2% / week, the thickness decay rate is no more than 1% / week, and the abrasion resistance is no less than 8000 cycles.

[0037] Optimizing the mid-height curve of the idler roller refers to designing and adjusting the transverse profile of the idler roller based on the stress distribution characteristics of the paper machine felt during normal operation. This results in a slightly convex shape or a specific nonlinear curved surface, achieving uniform pressure transmission across the felt width. The mid-height value is controlled within the range of 0.1–0.3 mm, effectively avoiding localized compaction due to excessive edge pressure and insufficient dewatering in the central area. The optimization of the idler roller's mid-height curve is determined using a combination of finite element simulation analysis and on-site measured data feedback, ensuring a stable pressure distribution under different machine speeds and load conditions. For example, in one embodiment, a parabolic mid-height curve (i.e., the cross-sectional profile approximates a quadratic function) is used, with its peak value located at the center of the roller and decreasing symmetrically towards both ends. In another optional embodiment, a piecewise linear or multi-segment arc structure can also be used to adapt to the needs of specific machine models or felt materials. By rationally designing the mid-height curve, compressive fatigue and wear caused by localized stress concentration in the felt are reduced, thereby slowing down the degradation process of thickness and air permeability.

[0038] The establishment of a pulp fiber control process refers to the refined management of the pulp suspension before it enters the wire section. The key focus is on controlling the content of fine fibers in the papermaking raw materials within the range of 12%–18%, and ensuring a pulp cleanliness of 98%–99%. An excessively high proportion of fine fibers can easily cause clogging of the felt pores, reducing dewatering efficiency and accelerating structural densification; an excessively low proportion will affect the uniformity and strength of the paper. Therefore, this application achieves precise control of fiber composition by configuring a high-efficiency pulp screening system, a multi-stage sand removal device, and dynamic headbox control technology. Furthermore, by combining an online turbidity meter and an image recognition system to monitor the pulp state in real time, the dilution water ratio and chemical addition amount are automatically adjusted to ensure uniform fiber dispersion and that the impurity content meets standards. In a modified embodiment, a grading screening process can be introduced to process coarse and long fibers and fine fibers separately before mixing them in a predetermined ratio for pulp supply, further improving control precision.

[0039] The two aforementioned technical approaches—optimization of the idler roller's high-curve profile and pulp fiber control process—have a synergistic effect: the former improves the stress environment of the felt at the mechanical contact level, reducing the accumulation of physical damage; the latter reduces the pollution load at the source of raw materials, maintaining the unobstructed flow of internal channels in the felt. Together, they significantly inhibit degradation behaviors of the felt during long-term operation, such as structural compression, pore blockage, and surface wear.

[0040] Through the above-described steps, this application achieves effective maintenance of key performance indicators of the felt during normal operation. By optimizing the high-pressure curve of the idler rollers, the pressure distribution is more uniform, reducing the risk of localized over-compaction. Simultaneously, by establishing a stable pulp fiber control process, excessive deposition of fine fibers inside the felt is effectively prevented, maintaining its good permeability and elasticity. Therefore, this solves the technical problems of rapid decrease in air permeability, significant thickness reduction, and shortened service life of felts in the middle of use, as seen in existing technologies. It achieves technical effects such as a felt air permeability decay rate of no more than 2% / week, a thickness decay rate of no more than 1% / week, and abrasion resistance of no less than 8000 cycles, extending the efficient service life of the felt and improving production stability and consistency of base paper quality. Example

[0041] Based on the above embodiments, this embodiment further provides: Step (3) is achieved through an online data acquisition and early warning system. The system acquires data at a frequency of no less than once per minute and issues an early warning signal within 5 minutes after the monitoring data triggers the early warning threshold.

[0042] The online data acquisition and early warning system is a technical device used to monitor key performance parameters of the paper machine felt in real time and continuously throughout its entire life cycle. The system includes sensor units, a data acquisition module, a communication interface, a central processing unit, and an alarm output module. It can automatically acquire data on core indicators such as felt running resistance, dewatering efficiency, and the uniformity of the produced base paper, and perform intelligent judgment and response based on preset thresholds. Deployed in the paper machine control system, the system can be integrated with a DCS (Distributed Control System) or a PLC (Programmable Logic Controller) to achieve closed-loop control.

[0043] The system's data acquisition frequency is set to no less than once per minute, meaning a complete data sampling cycle is completed at least once every 60 seconds. This high-frequency acquisition ensures precise capture of changes in the blanket's condition, making it particularly suitable for identifying early performance degradation characteristics, such as subtle signs of deterioration like slight increases in resistance, localized decreases in dehydration capacity, or the initial appearance of uniformity fluctuations. For example, in one implementation scenario, the system uses a pressure transmitter to monitor the pressure difference across the vacuum chamber to indirectly reflect dehydration efficiency, with a sampling interval of 45 seconds; simultaneously, an infrared force measuring device detects changes in blanket tension to calculate operating resistance, with a sampling frequency of twice per minute. This configuration meets the minimum frequency requirement while allowing for dynamic adjustment of the sampling density based on actual operating conditions, thus improving monitoring sensitivity.

[0044] When the collected data reaches or exceeds the preset warning threshold—for example, a 30% increase in blanket running resistance compared to the initial value, a 25% decrease in dewatering efficiency, or a paper uniformity deviation of ±3%—the system immediately initiates the alarm judgment process. After filtering, normalizing, and trend analyzing the received data, the central processing unit confirms that the abnormal state persists and is not caused by transient interference. If so, it generates and sends a warning signal within 5 minutes of the triggering condition being met. This response time is capped at 5 minutes, ensuring that operators have sufficient time to intervene and prevent the fault from escalating to the point of machine downtime or batch product quality defects.

[0045] Warning signals can be output in various ways, including but not limited to HMI (Human-Machine Interface) pop-up prompts, activation of audible and visual alarms, SMS push notifications to maintenance terminals, or automatic writing to MES (Manufacturing Execution System) event logs. In an optional embodiment, the system is also configured with a tiered alarm mechanism, dividing warnings into "Attention Level" (first time approaching the threshold) and "Action Level" (continuously exceeding the limit), and corresponding to different response strategies to enhance management flexibility.

[0046] Furthermore, the system supports historical data storage and retrospective analysis, with all collected records retained for at least 90 days, facilitating subsequent research on blanket lifespan modeling, failure mode analysis, and process optimization. The data storage format is compatible with common industrial database standards (such as OPC UA or Modbus TCP protocol) and can be integrated with enterprise-level big data platforms for in-depth data mining.

[0047] Through the above-described steps, this application achieves high-density, low-latency monitoring of the late-stage performance degradation process of felt. Because a data acquisition frequency of at least once per minute is set, the system can promptly capture key inflection points in felt performance evolution; and because a 5-minute early warning response time limit is specified, abnormal situations are ensured to be quickly communicated and handled. This solves the problems of excessive felt wear and uncontrolled paper quality caused by insufficient monitoring frequency or delayed alarms in existing technologies, thereby extending the effective service life of felt, reducing the risk of unplanned downtime, and improving the stability and intelligence level of the production line. Example

[0048] Based on the above embodiments, this embodiment further provides: The online data acquisition and early warning system integrates a visual monitoring unit for real-time monitoring of physical damage to the blankets.

[0049] The visual monitoring unit is a non-contact detection device based on image perception technology, positioned at key locations along the paper machine's felt running path to continuously and dynamically capture images of the felt surface. This visual monitoring unit includes a high-definition industrial camera, a light source system, and an image processing module. The high-definition industrial camera can use CMOS or CCD sensors, featuring high frame rates (≥30 frames / second) and high resolution (≥5 megapixels). It is installed on either side or above the felt to capture its running status from multiple angles. The light source system is a dimmable LED array, providing a stable and uniform lighting environment to avoid false detections caused by reflections or shadows. The image processing module incorporates edge detection, morphological analysis, and deep learning recognition algorithms (such as convolutional neural networks, CNN) to extract features such as texture anomalies, cracks, holes, and wear bands from the original image.

[0050] The visual monitoring unit automatically identifies and marks physically damaged areas by comparing the current blanket image with the initial reference image in real time, combined with preset damage judgment thresholds (such as linear defects with a damage area > 1 cm² or a length > 2 cm). When a damage signal that meets the warning conditions is detected, the system will trigger an alarm mechanism and perform data fusion analysis with performance parameters such as operating resistance and dehydration efficiency to improve the accuracy and robustness of fault judgment.

[0051] Furthermore, the visual monitoring unit supports multiple deployment methods: it can be fixedly installed in vulnerable areas such as before and after the vacuum chamber, or near the drive roller, or configured as a mobile inspection device to perform periodic scanning with the guide rail. Its communication interface is compatible with mainstream industrial protocols (such as Modbus TCP and PROFINET), allowing seamless integration with the central control platform of an online data acquisition and early warning system for remote monitoring and historical data traceability.

[0052] Through the above-described steps, this application achieves visualized and automated monitoring of physical damage to blankets, overcoming the shortcomings of traditional methods that rely on indirect performance indicators (such as decreased dehydration efficiency and increased operating resistance) to detect localized mechanical damage in a timely manner. By introducing direct observation methods, blankets can be identified at the stage of minute cracks or localized wear, allowing for early intervention for maintenance or replacement, preventing sudden breakages that could lead to downtime, and improving production continuity and safety. Simultaneously, this visual monitoring unit, working in conjunction with other sensor data, enhances the overall reliability of the final monitoring stage, providing a more comprehensive state awareness capability for full lifecycle management. Example

[0053] Paper machine felts play a crucial role in the production of tissue paper, performing key functions such as dewatering, forming, and transfer. Their performance directly impacts the quality of the base paper, production line efficiency, and overall manufacturing costs. Currently, the industry commonly faces problems such as long adaptation periods after felts are installed, short normal operating cycles, and rapid performance degradation at the end of the process, leading to frequent felt replacements, speed limitations, and significant fluctuations in product quality. Especially under medium- and high-speed paper machine operating conditions, without systematic control measures for each stage of the felt's entire lifecycle, stable and efficient continuous production is difficult to achieve. Existing technologies largely rely on experience-based adjustments to equipment parameters or the addition of single additives, lacking an integrated control system that deeply integrates process, chemistry, and monitoring, thus failing to meet the demands for precise, intelligent, and end-to-end optimization. Therefore, there is an urgent need to construct a dedicated system architecture capable of fully implementing end-to-end pre-compression production optimization methods to effectively translate theoretical methods into engineering applications.

[0054] This application makes the following: A paper machine felt pre-compression production system, used to implement the full life-cycle pre-compression production optimization method for paper machine felts according to any one of claims 1 to 4, comprising: The parameter control module is used to adjust the roller line pressure, vacuum degree, cleaning pressure and frequency in steps (1) and (2); The additive addition module is used to perform the ratio and concentration control of chemical additives and composite additives in steps (1) and (2); The online monitoring module is used to collect and provide real-time early warning of data on blanket running resistance, dewatering efficiency, and paper uniformity in step (3).

[0055] This system integrates three major functional modules: parameter control, additive management, and online monitoring, forming a closed-loop control system that fully supports the automated management of the entire process of blanket operation, from rapid activation at the initial stage, stable operation in the middle stage, to final status assessment. The parameter control module dynamically adjusts the operating parameters of key equipment according to preset strategies, ensuring that the roller linear pressure, vacuum box negative pressure, blanket cleaning pressure, and their operating frequency are always within the optimal range. This prevents insufficient or excessive compaction of the blanket structure due to initial parameter mismatch. This module can remotely issue commands based on a PLC or DCS control system and, in conjunction with on-site installed pressure sensors, vacuum gauges, and solenoid valves, achieves precise feedback control, featuring fast response, high stability, and strong fault tolerance. For example, during the adaptation period, the system automatically sets the linear pressure of the idler roller to 18 kN / m (within the range of 15–22 kN / m) and maintains the vacuum at -50 kPa. At the same time, it triggers the high-pressure spray device to rinse the blanket every 12 minutes to ensure that the pore structure of the blanket opens quickly and keeps the cleaning channel unobstructed. After entering the normal period, the system further tightens the control tolerance to keep the linear pressure fluctuation within ±0.5 kN / m and the vacuum fluctuation within ±2 kPa, thereby improving the uniformity of dewatering and the stability of operation.

[0056] The additive addition module focuses on the precise and programmed management of the chemical dosing process, covering the metering and delivery of various functional agents such as penetrants, lubricants, and antistatic agents and bactericides contained in composite additives. This module typically consists of a storage tank, metering pump, mixer, and concentration detection unit. It can automatically complete the preparation and dosing of additives according to preset formula ratios, ensuring the consistency and repeatability of the types and concentrations of additives required at different stages. During the adaptation period, the system injects a 0.2% penetrant and a 0.15% lubricant into the slurry or spray water according to instructions to promote fiber network reconstruction and reduce frictional damage. After entering the normal operation period, it switches to composite additive supply mode, preparing a composite solution with a total concentration of 0.4% according to the ratio of penetrant:antistatic agent:bactericide = 1:0.8:0.5, continuously adding it to inhibit microbial growth, reduce static electricity accumulation, and delay blanket clogging. This module also supports manual intervention and abnormal alarm functions; for example, it automatically shuts down and prompts for maintenance when a flow deviation exceeds ±5%.

[0057] The online monitoring module, acting as the system's sensing hub, continuously tracks the blanket's operating status, focusing on collecting key indicators such as blanket running resistance, dewatering efficiency trends, and the uniformity of the produced base paper. Data acquisition is conducted at least once per minute to ensure the detection of even minor signs of deterioration. Running resistance can be indirectly obtained by measuring the drive motor current or the force on the tension roller; dewatering efficiency is calculated by comparing the moisture content or free drainage before and after the vacuum chamber; base paper uniformity is determined online using a beta-ray scanner or infrared imaging technology to measure the standard deviation of the substrate's quantitative distribution. When any of the above parameters reaches a preset warning threshold—such as a 30% increase in running resistance, a 25% decrease in dewatering efficiency, or a uniformity deviation widening to ±3%—the system issues a graded warning signal within 5 minutes, reminding operators to take intervention measures. If the situation continues to deteriorate to the replacement threshold (resistance +50%, dewatering efficiency -40%, uniformity deviation ±5%), it is marked as the end of its lifespan and replacement is recommended. This module can also integrate a visual monitoring unit, using an industrial camera to periodically capture images of the blanket surface to identify physical defects such as edge tears, wear, and embedded foreign objects, enhancing the judgment capabilities.

[0058] The three modules are interconnected via industrial communication protocols (such as Modbus TCP and OPC UA), sharing timestamps and synchronizing data streams to form a closed-loop control logic of "sensing—analysis—decision-execution." Parameter adjustment and additive addition are dynamically corrected based on data feedback from online monitoring, realizing a shift from passive response to proactive control. For example, when monitoring detects a slow decline in dewatering efficiency, the system can preemptively fine-tune the vacuum level or increase the cleaning frequency to prevent sudden performance changes; or, when a slight fluctuation in the uniformity of the base paper is detected, the dosage of composite additives can be adjusted in conjunction to improve filtration consistency.

[0059] Through the above technical solution, this application achieves systematic integration and intelligent control of key process links throughout the entire life cycle of paper machine felts. By setting up dedicated functional modules for executing optimization strategies at each stage, the previously scattered manual control, intermittent testing, and post-maintenance processes are transformed into a fully automated, data-driven collaborative operation mode, significantly improving felt utilization efficiency and the stability of raw paper quality. This system not only accurately executes the process described in claims 1 to 4, but also provides a reliable technical carrier for its implementation, solving the problems of reliance on manual experience, delayed control, and slow response in traditional production. It effectively addresses industry pain points such as long felt adaptation periods, rapid degradation, and numerous monitoring blind spots, achieving the technical effects of extending service life, increasing machine speed, and reducing maintenance costs.

[0060] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for optimizing the pre-press production of a full life cycle of a paper machine felt, characterized in that, Comprising the following sequential steps: (1) Adaptation period fast activation step: Within the initial 24-36 hours of the operation of the felt on the paper machine, the operating parameters of the paper machine are controlled as follows: The line pressure of the carrier roll is controlled within the range of 15-22 kN / m; The vacuum degree of the vacuum box is controlled within the range of -40~-60 kPa; The cleaning pressure of the felt is controlled within the range of 0.8-1.2 MPa, and the cleaning frequency is controlled at once every 10-15 minutes; Chemical additives are added to the system, wherein the concentration of the penetrating agent is controlled within the range of 0.1-0.3%, and the concentration of the lubricant is controlled within the range of 0.08-0.2%; (2) Normal period stable operation step: After the felt completes the adaptation period, it enters the normal operation stage, in which: The medium-high of the carrier roll is controlled within the range of 0.1-0.3 mm, the vacuum degree fluctuation is controlled within ±2 kPa, and the line pressure fluctuation of the carrier roll is controlled within ±0.5 kN / m; A composite additive is used, which comprises a penetrating agent, an antistatic agent, and a bactericide, with a ratio of 1:0.8:0.5, and the total concentration of the composite additive is controlled within the range of 0.3-0.5%; The content of fine fibers in the paper pulp used for papermaking is controlled within the range of 12-18%, and the cleanliness reaches 98-99%; (3) End period monitoring and early warning step: During the whole life cycle of the felt operation, online monitoring is continuously performed, and early warning and decision-making are made according to the following threshold values: The running resistance of the felt, the dewatering efficiency, and the uniformity of the produced base paper are monitored in real time; When the running resistance of the felt increases by 30%, the dewatering efficiency decreases by 25%, or the uniformity deviation of the base paper reaches ±3%, the system sends a warning signal; When the running resistance of the felt increases by 50%, the dewatering efficiency decreases by 40%, or the uniformity deviation of the base paper reaches ±5%, the system prompts to replace the felt.

2. A full life cycle pre-press production optimization method for paper machine felts according to claim 1 characterized in that: In the step (2), by optimizing the carrier roll medium-high curve and establishing a paper pulp fiber control process, the air permeability decay rate of the felt is not greater than 2% / week, the thickness decay rate is not greater than 1% / week, and the wear resistance is not less than 8000 times.

3. A full life cycle pre-press production optimization method for paper machine felts according to claim 1 characterized in that: The step (3) is realized by an online data acquisition and early warning system, which collects data at a frequency of not less than 1 time / minute, and sends a warning signal within 5 minutes after the monitoring data triggers the early warning threshold.

4. A full life cycle pre-press production optimization method for paper machine felts according to claim 1 characterized in that: The online data acquisition and early warning system is integrated with a visual monitoring unit for real-time monitoring of the physical damage of the felt.

5. A paper machine felt pre-press production system for implementing the full life cycle pre-press production optimization method of any one of claims 1 to 4, characterized by, Comprise: A parameter control module for adjusting the line pressure, vacuum degree, cleaning pressure, and frequency of the carrier roll in steps (1) and (2); An additive adding module for controlling the proportioning and concentration of the chemical additives and the composite additives in steps (1) and (2); An online monitoring module for collecting and real-time warning of the data of the running resistance of the felt, the dewatering efficiency, and the uniformity of the base paper in step (3).