Printing System Drying And Dampening Control For Paper-Web Stability
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Solution Overview
Problem
The challenge of maintaining consistent dimensional accuracy and moisture content in paper webs during printing is exacerbated by varying web speeds, particularly in inline operations, leading to quality issues in downstream processes like corrugated board production.
Innovation Solution
A method and system that control the shrinkage and moisture content of paper webs by adjusting drying and humidification performance based on actual and target values, using sensors and a control system to maintain stability despite varying web speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the web speed is varied to improve productivity and flexibility in inline operation, then the production efficiency increases, but the dimensional accuracy and moisture content consistency of the paper web deteriorate
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting drying and humidification parameters (temperature, humidity levels, exposure time) based on the actual web speed. The control system modifies these parameters in real-time to compensate for speed variations, ensuring consistent dimensional accuracy and moisture content regardless of the production speed
Solution Approach 2:
The patent implements feedback control by continuously measuring actual web speed, dimensional changes, and moisture content, then using this information to adjust drying and humidification parameters. The control system receives feedback from sensors and automatically modifies operating parameters to maintain manufacturing precision despite speed variations
2Adaptability or versatility
If the web speed is varied to enable job changes without stopping the system, then the adaptability and flexibility improve, but the moisture content control and shrinkage consistency worsen
Solution Approach 1:
The patent applies preliminary action by pre-adjusting drying and humidification parameters based on anticipated web speed changes or job requirements. The control system proactively modifies parameters before actual speed changes occur, preventing moisture content instability rather than merely reacting to it
Solution Approach 2:
The patent implements dynamics by making the drying and humidification system adaptable and responsive to changing conditions. The control system dynamically adjusts parameters in real-time based on web speed variations, enabling the system to maintain moisture content stability across different operating conditions and job types
3Speed
If the drying capacity is increased to reduce moisture content faster, then the processing speed improves, but the paper web shrinkage increases and dimensional accuracy deteriorates
Solution Approach 1:
The patent applies parameter changes by adjusting drying parameters (temperature, air flow, exposure time) and humidification parameters in a coordinated manner. The control system modifies these parameters dynamically to achieve optimal moisture removal rates while minimizing excessive shrinkage and maintaining print dimensional accuracy
Solution Approach 2:
The patent uses humidification as an intermediary process to counterbalance the shrinkage effects of drying. By introducing moisture back into the paper web after drying, the system compensates for dimensional changes and maintains accuracy while still achieving efficient moisture removal
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables flexible operation of printing systems with consistent shrinkage and moisture levels, ensuring high-quality prints and reducing scrap by allowing job changes without stopping the system.
Implementation Method 1
A dryer (e.g., a hot-air dryer and/or IR dryer) is used to dry the paper web, which shrinks the print and the paper web and also removes moisture from the paper web
Implementation Method 2
A humidifier is provided in order to humidify the paper web and thereby cause swelling of the paper web
Data Source
Figure 1~2
AI summary
A method for operating a printing plant (2) is specified, wherein the printing plant (2) has a printing unit (8), for printing a paper web (10) in accordance with a predefined job with predefined job data, wherein the paper web (10) is conveyed at a web speed through the printing plant (2), wherein the printing plant (2) has at least one dryer (18, 20) with an adjustable drying performance, in order to dry the paper web (10), as a result of which the paper web (10) experiences shrinkage, wherein the printing plant (2) has at least one dampener (22) with an adjustable dampening performance, in order to dampen the paper web (10) and, as a result, to adjust a moisture content of the paper web (10), wherein an actual shrinkage and an actual moisture content are determined for the paper web (10), and a setpoint shrinkage and a setpoint moisture content are predefined, wherein the shrinkage and the moisture content are regulated to the setpoint shrinkage and the setpoint moisture content by way of setting of the drying performance and the dampening performance in a manner which is dependent on the actual shrinkage and the actual moisture content. Furthermore, a printing plant (2) and a combination (6) consisting of a printing plant of this type and a corrugated board plant (4) are specified.