Press Felt Base Fabric Irregular Weave Pattern
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Press felts used in papermaking often exhibit interference patterns due to misalignment of yarns, leading to uneven water removal and sheet marking, which are not effectively addressed by existing solutions, particularly in single layer woven structures.
Innovation Solution
A press felt with two stacked layers of a woven single layer base fabric, where the warp yarns are polymeric monofilaments interwoven with cabled and single polymeric monofilament weft yarns, arranged in an irregular repeating pattern to vary yarn spacing and eliminate interference patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If regular repeating weave pattern is used in single layer base fabric, then manufacturing simplicity is maintained, but interference patterns occur when two layers are superimposed
Solution Approach 1:
The patent applies asymmetry by using an irregular repeating weave pattern where the sequence of warp and weft yarns varies within each repeat. Specifically, the pattern includes sections with different yarn densities and spacing arrangements, creating an asymmetric structure that prevents regular interference patterns when two fabric layers are superimposed, while still maintaining a repeating nature for manufacturability
Solution Approach 2:
The patent implements local quality by creating zones with different yarn characteristics within the same fabric. The irregular repeating pattern includes areas with varying yarn spacing, different yarn types (monofilament vs. cabled), and altered weave structures in specific sections, allowing different parts of the fabric to have optimized local properties that collectively eliminate interference patterns
2Volume of stationary object
If two layers of single layer base fabric are stacked to form press felt, then void volume and water reservoir capacity are increased, but interference patterns cause uneven water removal and sheet marking
Solution Approach 1:
By using irregular repeating patterns in both stacked layers, the patent creates asymmetric yarn distributions that prevent the formation of regular interference patterns. The asymmetry ensures that when layers are superimposed, the yarns do not align in predictable patterns that would create zones of uneven water removal, thus maintaining uniform performance across the entire press felt surface
Solution Approach 2:
The patent changes the structural parameters of the base fabric by introducing irregular repeating patterns with varied yarn spacing, different yarn types, and altered weave sequences. These parameter changes in the single layer fabric translate to corresponding changes in the stacked two-layer structure, eliminating the uniformity issues that cause interference patterns while preserving the increased void volume benefit
3Strength
If cabled monofilament weft yarns are used in single layer base fabric, then batt fiber adhesion is improved, but yarn interference patterns are exacerbated due to cable structure regularity
Solution Approach 1:
The patent applies local quality by strategically placing cabled monofilament weft yarns in specific sections within the irregular repeating pattern, rather than uniformly throughout. This allows cabled yarns to provide enhanced batt adhesion in areas where it is most beneficial, while other sections use different yarn configurations that help disrupt potential interference patterns, creating a balanced overall structure
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A press felt formed of two stacked layers of woven single layer base fabric, each layer being formed by warp yarns interwoven with two systems of weft yarns according to a single layer weave pattern. The layers are needled with a batt layer. In the woven single layer base fabric: a) the warp yarns are polymeric monofilaments arranged as a single layer and there are two systems of weft yarns; b) the first system of weft yarns are formed by cabled polymeric monofilaments and the second system of weft yarns are single polymeric monofilaments; c) the cabled polymeric monofilaments are 50% to 85% in one repeat; d) the cabled monofilaments are each formed of at least two monofilaments which are cabled together; and e) at least two of the cabled weft yarns in each repeat are adjacent to each other.