Semicontinuous Belt Protuberance Pattern for Caliper Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing secondary belts used in the papermaking process struggle to effectively control and maintain caliper and cross-direction (CD) stretch properties of cellulosic fibrous structures, leading to frequent replacements and increased manufacturing costs due to high temperature and pressure challenges.
Innovation Solution
A macroscopically monoplanar secondary belt with a reinforcing structure and a semicontinuous pattern of protuberances and deflection conduits, where the protuberances have a specific width ratio and are spaced to enhance durability and control caliper generation, while allowing for airflow and vacuum applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing secondary belts are used in the papermaking process, then manufacturing can proceed, but control over caliper and CD stretch properties deteriorates and belt life is reduced due to high temperature and pressure challenges
Solution Approach 1:
The belt surface is segmented into discrete protuberances and deflection conduits arranged in a semicontinuous pattern. This segmentation allows different regions of the belt to perform specific functions: protuberances provide structural support and define calibration zones, while deflection conduits allow controlled deformation. The pattern includes spaced-apart primary protuberances with secondary protuberances positioned between them, creating distinct functional zones that maintain precision while withstanding processing conditions
Solution Approach 2:
Different regions of the belt are given different properties through the semicontinuous pattern design. Primary protuberances have specific dimensions and spacing to provide overall structural support, while secondary protuberances positioned between them have different spacing to create localized calibration zones. The deflection conduits between protuberances have specific geometry to allow controlled local deformation. This local differentiation enables simultaneous control of caliper and CD stretch properties while maintaining belt durability under high temperature and pressure
2Manufacturing precision
If the belt pattern is made continuous, then control over fibrous structure properties is improved, but belt complexity and manufacturing difficulty increase
Solution Approach 1:
Instead of implementing a fully continuous pattern, the invention uses a semicontinuous pattern where primary protuberances are spaced apart with secondary protuberances positioned between them. This partial pattern provides sufficient control over caliper and CD stretch properties without requiring the complexity of a completely continuous structure. The spaced arrangement reduces manufacturing complexity while maintaining functional effectiveness through the strategic positioning of protuberances and deflection conduits
Solution Approach 2:
The continuous pattern is segmented into discrete elements: primary protuberances, secondary protuberances, and deflection conduits. This segmentation simplifies manufacturing by allowing each element to be formed independently through molding or embossing processes. The segmented pattern maintains control functionality through the repeated modular units while reducing overall complexity compared to a truly continuous structure
3Manufacturing precision
If protuberances are made closer together, then control over caliper is improved, but belt durability decreases due to increased stress concentration
Solution Approach 1:
The protuberance arrangement is segmented into two levels: primary protuberances spaced further apart to maintain belt strength and structural integrity, and secondary protuberances positioned between the primary ones at closer spacing to provide localized caliper control. This hierarchical segmentation allows caliper precision in critical zones without subjecting the entire belt to high stress concentrations that would reduce durability
Solution Approach 2:
Different spacing configurations are applied locally: primary protuberances have larger spacing to preserve belt strength, while secondary protuberances have smaller spacing in between to provide enhanced caliper control where needed. The deflection conduits between protuberances are designed with specific geometry to distribute stresses. This local differentiation achieves precise caliper control in specific zones without compromising overall belt strength and durability
Data Source
AI summary
A macroscopically monoplanar secondary belt for manufacturing a cellulosic fibrous structure is provided. The belt, having two mutually orthogonal principal directions, a machine direction and a cross machine direction, and having a reinforcing structure; and a framework of protuberances joined to said reinforcing structure and extending outwardly therefrom to define deflection conduits between the protuberances, the framework of protuberances having a semicontinuous pattern and the deflection conduits having a semicontinuous pattern, is further provided. The protuberances and the deflection conduits have a vector component extending substantially throughout one principal direction of the belt, each protuberance of the pattern being spaced apart from an adjacent protuberance in the pattern. The protuberances have primary protuberances having a first width, T and the nodes have a second width, N, wherein a ratio of N to T is from about 1.5 to about 5.