Corrugated Board Line Thermography for Moisture and Defect Control
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Solution Overview
Problem
Existing corrugated board production lines face challenges in accurately controlling temperature and moisture levels of continuous paper and board webs, leading to issues such as warping, gluing defects, and waste due to the complexity and limitations of current moisture and temperature sensors.
Innovation Solution
A plant and method utilizing thermographic cameras to detect temperature profiles of continuous webs in real-time, with a control system to adjust process parameters based on detected temperature differences and moisture content, and optional systems for detecting transverse shrinkage to correct abnormalities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If infrared temperature sensors are used to control temperature in the wet-end, then temperature monitoring is enabled, but measurement precision and reliability are insufficient for detecting subtle temperature variations that affect moisture content
Solution Approach 1:
The patent replaces contact-based mechanical temperature sensors with non-contact laser-based optical measurement systems. The laser interferometry method measures temperature-induced refractive index changes in the paper web without physical contact, eliminating sensor drift and contamination issues while providing superior precision for detecting subtle temperature variations affecting moisture content.
Solution Approach 2:
The patent measures temperature indirectly through optical parameter changes (refractive index, light interference patterns) rather than direct electrical sensor readings. By monitoring how temperature affects the optical properties of the paper web and using laser interferometry to detect these changes, the system achieves higher measurement precision and reliability for process control.
2Loss of information
If complex processing lines with multiple sensors are used, then monitoring capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent makes the laser-based optical measurement system serve multiple functions: it simultaneously measures temperature, infers moisture content, monitors paper web quality, and provides feedback for process control. This single multi-functional system replaces what would traditionally require multiple separate sensors and measurement systems, reducing overall device complexity while maintaining comprehensive monitoring capability.
Solution Approach 2:
The patent introduces light as an intermediary medium to transfer information about the paper web's physical state. The laser beam interacts with the paper web and carries information about temperature and moisture content back to the detection system, enabling comprehensive monitoring through a single non-contact measurement approach rather than multiple direct sensors.
3Manufacturing precision
If traditional moisture and temperature sensors are used, then basic monitoring is achieved, but manufacturing precision suffers due to inability to detect subtle variations affecting gluing quality
Solution Approach 1:
The patent replaces traditional electrical sensors with laser-based optical measurement systems that detect temperature and moisture through light interference and refractive index changes. This substitution provides superior measurement precision for detecting subtle variations in the paper web's physical state, enabling better control of gluing conditions and improved manufacturing precision for defect-free corrugated board production.
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
Enhances the accuracy and efficiency of temperature and moisture control, reducing defects and waste by allowing for real-time adjustments and proactive intervention in the production process.
Implementation Method 1
at least one first thermographic camera positioned along an advancement path of at least one of said: first continuous paper web, second continuous paper web, third continuous paper web, continuous single face corrugated board web, continuous corrugated board web for detecting thermographic images of said at least one continuous web
Data Source
AI summary
The plant for producing a corrugated board includes one or more single facers and a double facer, as well as respective unwinders for unwinding reels of paper webs. Arranged along the production line, in suitable positions, are thermographic cameras which acquire images through which it is possible to trace the various characteristics of the cardboard, for example the moisture content thereof, detect manufacturing defects, after which it is possible to intervene on one or more process parameters so as to eliminate the causes of the defects.