Press Fabric Macro-Voids for Textured Paper Dewatering
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Solution Overview
Problem
Current press fabrics in the papermaking process lack the ability to effectively impart a desired texture to paper products while maintaining efficient water removal and preventing rewetting, leading to suboptimal surface characteristics and dewatering efficiency.
Innovation Solution
A press fabric with macro-voids on the sheet-contact side, which allows for the creation of a textured surface by compressing cellulose fibers into void volumes, reducing dewatering efficiency and enabling custom texture patterns without requiring machine rebuilds or new installations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If press fabric has a smooth surface, then water removal efficiency is improved, but surface texture quality deteriorates
Solution Approach 1:
The press fabric incorporates macro-voids as localized features distributed across the sheet contact side, creating regions of different properties (voids for texture, solid matrix for water removal) within the same fabric structure. This allows simultaneous achievement of surface texturing and efficient water drainage through spatial differentiation of functions.
Solution Approach 2:
The press fabric utilizes a porous structure with deliberately engineered macro-voids (larger pores) on the sheet contact side to impart texture, while maintaining the overall porosity and permeability of the fabric for water removal. The macro-voids create surface texture through fiber displacement without compromising the fabric's water acceptance and drainage capabilities.
2Manufacturing precision
If press fabric has macro-voids for texture, then surface texture is improved, but dewatering efficiency deteriorates
Solution Approach 1:
The macro-voids are positioned specifically on the sheet contact side of the press fabric, while the water acceptance and drainage functions are maintained through the fabric's overall porous structure and the machine side configuration. This localized texturing minimizes interference with the water removal pathway.
Solution Approach 2:
The press fabric employs a composite structure combining macro-void regions for texturing with a porous matrix structure for water removal. The fabric integrates different structural elements (macro-voids, porous matrix, potential multi-layers) to simultaneously achieve surface texturing and maintain dewatering efficiency.
3Volume of moving object
If press fabric has increased void volume, then bulk and absorbency are improved, but water retention increases
Solution Approach 1:
The macro-voids create localized bulk and absorbency enhancement at the sheet surface, while the overall fabric structure and machine side configuration control water retention. The surface macro-voids provide bulk without creating excessive water holding capacity that would prevent proper dewatering.
Solution Approach 2:
The press fabric utilizes controlled porosity with macro-voids to achieve desired bulk and surface absorbency characteristics. The porous structure is engineered to provide adequate void volume for texture and bulk while maintaining appropriate permeability for water removal during the pressing operation.
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 use of macro-voids in the press fabric results in reduced dewatering and allows for the production of higher bulk grades with specific surface textures, enhancing absorbency and ornamentation without increasing water reabsorption, as demonstrated by experimental results showing lower percent dryness and textured surface profiles.
Implementation Method 1
In the press nips, the cellulosic fibrous web is subjected to compressive forces which squeeze water therefrom, and which adhere the cellulosic fibers in the web to one another
Implementation Method 2
A large amount of water is drained from the slurry through the forming fabric
Implementation Method 3
The water is accepted by the press fabric or fabrics and, ideally, does not return to the paper sheet
Implementation Method 4
The heated drums reduce the water content of the paper sheet to a desirable level through evaporation
Implementation Method 5
which are internally heated by steam
Data Source
AI summary
Disclosed is a press fabric and related method to impart a texture to a cellulose product by having macro-voids in a complementary pattern on a sheet-contact side surface of the press fabric.