Creping Cylinder Coating Thickness Monitoring
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Solution Overview
Problem
The tissue making process faces challenges in achieving uniformity of the coating on the creping cylinder, leading to variations in sheet adhesion, material deposits, and degradation of final sheet properties such as absorbency, bulk, strength, and softness due to temperature, moisture, and chemical composition variations across the dryer surface.
Innovation Solution
A method involving a differential measurement system using eddy current and optical displacement sensors to monitor coating thickness non-contactingly, with optional adjustments to achieve uniformity and additional sensors for moisture and temperature control, ensuring precise application of Performance Enhancing Materials (PEM) on the creping cylinder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional contact-based measurement methods are used to monitor coating thickness, then measurement can be performed, but the measurement process physically contacts the coating and may contaminate or damage it
Solution Approach 1:
The patent replaces mechanical contact-based measurement systems with non-contact optical measurement systems. Specifically, it uses reflectance spectroscopy where light is directed at the coating and the reflected light is analyzed to determine coating thickness and properties, eliminating physical contact and associated contamination risks
Solution Approach 2:
The patent introduces light as an intermediary medium to transfer information about the coating properties without direct contact. The optical system uses light reflection characteristics to indirectly measure coating thickness and composition, serving as a mediator between the measurement device and the coating
2Manufacturing precision
If uniform coating application is achieved across the creping cylinder, then product quality consistency improves, but the complexity of monitoring and control systems increases
Solution Approach 1:
The patent divides the creping cylinder surface into multiple measurement zones, with optical sensors positioned to monitor different circumferential and radial positions independently. This segmentation allows targeted monitoring of specific problem areas without requiring a completely complex system covering the entire surface
Solution Approach 2:
The patent implements a feedback control system where optical measurement data is continuously fed back to control the coating application process. The system compares measured coating properties against target values and automatically adjusts coating parameters to maintain uniformity, reducing the need for overly complex manual monitoring
3Reliability
If real-time monitoring of coating properties is implemented, then coating quality can be controlled, but the cost and complexity of the measurement system increases
Solution Approach 1:
The patent employs self-calibrating optical measurement systems that automatically adjust for environmental conditions and sensor drift. The system uses reference standards and internal calibration mechanisms to maintain measurement accuracy without requiring complex external calibration equipment or frequent manual intervention
Solution Approach 2:
The patent utilizes changes in optical parameters (reflectance, absorption, scattering) of the coating material to infer coating thickness and composition. By monitoring these naturally occurring optical property changes, the system achieves reliable quality control using relatively simple optical sensors rather than complex analytical instruments
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
This method provides accurate monitoring and control of coating thickness and quality, reducing non-uniformities and defects, thereby enhancing the consistency of tissue products and minimizing creping cylinder wear, improving the efficiency and runnability of the tissue machine.
Implementation Method 1
utilizes a differential method, wherein said differential method utilizes a plurality of apparatuses that do not physically contact the coating
Implementation Method 2
utilizes a differential method, wherein said differential method utilizes a plurality of apparatuses that do not physically contact the coating
Data Source
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AI summary
A method for monitoring and controlling the thickness of coating on a creping cylinder is disclosed. The methodologies involve a coordinated scheme of apparatuses that function to monitor various aspects of a creping cylinder coating so that the thickness of the coating can be determined.