Seamless Press Felt Elastic Carrier Layer
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Solution Overview
Problem
Existing press felts face issues with sheet marking, batt shedding, and void volume loss due to seam-related discontinuities and fabric compaction, particularly in multiaxial constructions.
Innovation Solution
A seamless press felt design featuring an elastic intermediate yarn assembly with a CD array of polymeric yarns bonded to an elastic carrier material, located between inner and outer base fabric layers, which are spirally wound and needled with batt layers to join them, enhancing void volume and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiaxial press felts are used to reduce manufacturing time and costs, then productivity is improved, but sheet marking and batt shedding occur due to seam-related discontinuities
Solution Approach 1:
The patent removes the problematic seam structure from the press felt design. By using a seamless tubular base fabric constructed from spirally wound and bonded yarn assemblies, the invention eliminates seam-related discontinuities that cause sheet marking and batt shedding, while maintaining the productivity benefits of multiaxial construction techniques
Solution Approach 2:
The patent employs composite material structures by combining multiple yarn assemblies with different orientations (machine direction and cross-machine direction yarns) within a seamless tubular base fabric. This composite construction provides both the productivity advantages of multiaxial design and the uniformity needed to prevent sheet marking and batt shedding
2Object-generated harmful factors
If base fabric is woven to full width and length to ensure uniformity, then sheet marking is reduced, but manufacturing time and capital investment increase
Solution Approach 1:
The patent divides the base fabric construction into modular yarn assemblies that can be produced separately and then combined in a seamless tubular structure. This segmentation allows manufacturing to be done in smaller, more efficient units rather than requiring full-width weaving, reducing manufacturing time while maintaining uniformity through the seamless assembly process
Solution Approach 2:
The patent transitions from traditional planar weaving to a three-dimensional seamless tubular construction. By forming the base fabric as a continuous tube through spirally wound yarn assemblies, the invention eliminates the need for full-width weaving while maintaining uniformity, thus reducing manufacturing time and capital investment
3Object-generated harmful factors
If seamless construction is used to eliminate seams, then sheet marking is reduced, but device complexity increases
Solution Approach 1:
The patent merges multiple functional elements (base fabric, void volume provision, and structural support) into a single seamless tubular construction. By integrating these functions into one continuous structure formed from spirally wound yarn assemblies, the invention eliminates sheet marking while actually simplifying the overall device by removing seam-related components and assembly steps
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 reduces sheet marking and batt shedding while maintaining high void volume, providing improved seam uniformity and vibration resistance, and allowing for easier installation and reduced manufacturing time and costs.
Implementation Method 1
an elastic intermediate yarn assembly including a CD array of mutually parallel and regularly spaced polymeric yarns, each bonded to an elastic carrier material that is extensible by at least 1% of a relaxed length thereof
Implementation Method 2
At least one batt layer is needled through the inner and outer base fabric layers and the elastic intermediate yarn assembly to join the layers together
Data Source
AI summary
A seamless press felt is provided having inner and outer base fabric layers, which can be woven or non-woven, having an MD length and CD width, each including at least a first array of MD oriented yarns and being formed as a continuous unbroken tube structure. An elastic intermediate yarn assembly with parallel and regularly spaced CD yarns, each bonded to an elastic carrier material, is formed as a continuous unbroken tube structure, and is “socked” between the inner and outer base fabric layers. The elastic intermediate yarn assembly has an MD length that is from 1% to 10% less than the MD length of the press felt prior to assembly and is elastically stretched during assembly between the inner and outer base fabric layers. At least one batt layer needled through the inner and outer base fabric layers and the elastic intermediate yarn assembly to fornt he press felt.