Permeable Belt with Raised Land Areas for Tissue Dewatering
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Solution Overview
Problem
Existing papermaking belts do not effectively impart structure to tissue or towel products, leading to inefficiencies in dewatering and energy consumption, and impermeable belts can cause sheet rewetting issues during the production process.
Innovation Solution
A fabric structure that is permeable to air and water, featuring a series of raised land areas and corresponding depressions with voids greater than 50 microns in diameter, located only in the raised land areas, to enhance dewatering and texturing of the final product, while minimizing sheet rewet and improving creping uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an impermeable belt is used to provide structure to tissue or towel sheet, then sheet release and texturing are improved, but dewatering efficiency deteriorates and energy consumption increases
Solution Approach 1:
The patent applies porous materials by incorporating through-holes through the entire belt thickness and a porous surface layer with controlled pore structure. This allows water and air to pass through the belt during the drying process, significantly improving dewatering efficiency while maintaining the belt's structural integrity and texturing capabilities. The porous structure enables efficient moisture removal without compromising sheet release properties.
2Productivity
If a permeable belt is used to enhance dewatering, then dewatering efficiency is improved, but sheet rewet occurs during production
Solution Approach 1:
The patent applies local quality by creating different functional zones on the belt surface. The through-holes are strategically positioned to allow dewatering in specific areas, while the raised land areas provide structural support and control sheet release. The depressed areas between lands create capillary channels that manage moisture flow, ensuring that dewatering occurs efficiently without causing sheet rewet in other regions.
Solution Approach 2:
The patent applies composite materials by combining a woven substrate with a porous polymer coating layer. The woven substrate provides mechanical strength and dimensional stability, while the porous polymer coating layer controls fluid permeability and provides the texturing surface. This composite structure enables simultaneous achievement of good dewatering performance and prevention of sheet rewet.
3Reliability
If Through Air Drying is used to produce structured tissue or towel, then sheet softness and absorbency are improved, but energy consumption increases
Solution Approach 1:
The patent applies taking out by extracting the energy-intensive Through Air Drying process and replacing it with a mechanically assisted dewatering system. The belt's through-holes and porous structure enable efficient water removal through capillary action and gravity-driven flow, significantly reducing the need for high-energy air drying while maintaining sheet softness and absorbency properties.
4Reliability
If an impermeable belt with smooth surface is used, then sheet release is improved, but creping uniformity deteriorates
Solution Approach 1:
The patent applies another dimension by transitioning from a flat smooth surface to a three-dimensional surface with raised lands and depressed areas. The raised lands provide localized release points while the depressed areas create capillary channels for moisture management. This dimensional complexity enables simultaneous achievement of good sheet release and uniform creping by distributing stresses and moisture flow across multiple surface features.
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 fabric structure enhances dewatering efficiency, aids in texturing the final product, and reduces sheet rewet compared to impermeable or woven porous structures, resulting in a softer, more absorbent, and bulkier tissue or towel with improved creping uniformity.
Implementation Method 1
a series of voids adapted to allow passage of both water and air from the fabric surface into and/or through the structure
Implementation Method 2
a sheet contact surface pattern of a series of raised land areas and corresponding depressions that impart a texture to the tissue or towel sheet
Data Source
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AI summary
A fabric structure used to make textured tissue or towel or nonwovens, the structure being permeable to air and water, comprising a sheet contact surface having a pattern including a series of raised land areas and corresponding depressions adapted to impart a texture to the tissue or towel or nonwoven, and a series of through voids adapted to allow passage of both water and/or air from the fabric surface into and/or through the structure.