Sheet Former Thickness Control via Wire Cylinder Surface Area
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Solution Overview
Problem
Cylinder type sheet formers struggle to achieve uniform thickness in sheet forming bodies due to factors like material concentration, viscosity, and fiber quality, which change over time, leading to variations in the finished product.
Innovation Solution
A sheet former with a wire cylinder and a sheet-forming amount regulator that adjusts the amount of solid components by changing the surface area of the wire cylinder through a sheet-shaped regulator or air bubble regulator, allowing real-time regulation of thickness variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a cylinder type sheet former is used to manufacture board material from slurry, then the sheet forming process can be completed, but thickness variations of 5 to 30% occur in the width direction due to factors like material concentration, viscosity, and fiber quality changes over time
Solution Approach 1:
The invention applies a dynamic control system that continuously monitors thickness variations and adjusts the discharge amounts from multiple vessels in real-time. The discharge means are positioned to allow dynamic regulation of slurry flow rates, enabling the system to adapt to changing material properties and maintain uniform thickness despite variations in concentration, viscosity, and fiber quality over time.
Solution Approach 2:
The invention implements local quality control by dividing the sheet forming process into multiple zones corresponding to different vessels. Each vessel's discharge means can be independently regulated to compensate for local variations in material properties. This allows different regions of the sheet to receive optimized slurry discharge rates tailored to their specific thickness requirements, thereby achieving overall uniformity.
2Stress or pressure
If discharge means are provided in first and second vessels positioned opposite to each other with the cylindrical net interposed therebetween, then pressure distribution can be regulated, but this only addresses pressure as a factor and not other time-dependent factors like concentration and viscosity changes
Solution Approach 1:
The invention incorporates a feedback control system that measures actual thickness variations in the formed sheet and uses this information to adjust the discharge amounts from each vessel. The thickness measurement results are fed back to the control unit, which then modifies the discharge rates to compensate for deviations, creating a closed-loop system that continuously optimizes thickness uniformity based on real-time conditions.
Solution Approach 2:
The invention changes the control parameters from static pressure regulation to dynamic multi-parameter control. The system monitors and adjusts multiple variables including discharge flow rates, material concentration, and viscosity effects simultaneously. By changing these parameters dynamically based on their actual values and relationships, the system achieves superior thickness control compared to pressure regulation alone.
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
The solution effectively regulates the thickness of sheet forming bodies in the width direction, reducing variations and producing a smooth, uniform finished product by dynamically adjusting the amount of solid components based on measured thickness data.
Implementation Method 1
a wire cylinder (14) immersed in the slurry (13) inside the vessel (3) and making sheets from solid components in the slurry (13) while being rotated
Data Source
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AI summary
To provide a sheet former capable of suitably regulating the thickness of a sheet forming body in a width direction in response to factors changing with time. A sheet former includes at least one vessel which stores slurry as a raw material, a wire cylinder immersed in the slurry inside the vessel and making sheets from solid components in the slurry while being rotated, and a sheet-forming amount regulator which regulates an amount of the solid components for making sheets by the wire cylinder in a width direction in accordance with a thickness of a sheet forming body in the approximately width direction formed for making sheets by the wire cylinder.