Woven Press Felt With Welded Intersections to Resist Compaction
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Solution Overview
Problem
Press felts used in paper or cardboard production experience compaction due to repeated loads in press nips, leading to reduced permeability and increased compaction, which is addressed by providing a woven base structure with integral bonds between longitudinal and transverse threads to prevent thread displacement.
Innovation Solution
A press felt with a woven base structure featuring integral bonds, such as welding, between longitudinal and transverse threads at specific intersections to prevent compaction and maintain permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple fabric plies are stacked to increase liquid absorption volume and strength, then the void volume increases, but the tendency for compaction increases
Solution Approach 1:
The patent embeds a first fabric ply within a second fabric ply to form a nested multi-ply structure. This nesting arrangement increases the void volume for liquid absorption while the integrated structure resists compaction better than simply stacked plies.
Solution Approach 2:
The patent introduces integral bonds at intersections between longitudinal and transverse threads, adding a dimensional constraint mechanism. This creates a three-dimensional network structure that prevents thread displacement and reduces compaction while maintaining absorption capacity.
2Stress or pressure
If fabric plies are compressed under repeated press nip loads, then the felt provides dewatering function, but permeability decreases due to compaction
Solution Approach 1:
The patent pre-establishes integral bonds at thread intersections before the felt undergoes press nip loading. These pre-formed bonds prevent thread displacement and compaction during subsequent pressing operations, maintaining stable permeability throughout the felt's service life.
3Ease of operation
If threads are allowed to displace under load, then the felt is flexible, but compaction increases and permeability reduces
Solution Approach 1:
The patent applies integral bonding selectively at thread intersections rather than throughout the entire fabric structure. This localized bonding maintains flexibility in the fabric while preventing displacement at critical intersection points, balancing flexibility with permeability stability.
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 integral bonds between threads reduce compaction and maintain permeability, ensuring a consistent liquid absorption capacity and structural integrity.
Implementation Method 1
the longitudinal threads and the transverse threads of the first fabric ply are welded to one another at at least 5% of the intersections
Implementation Method 2
the felt is compressed, and, after passage through the press nip, the felt expands again substantially to its original thickness
Data Source
AI summary
A press felt for a machine for producing a fibrous material web has a woven base structure and a nonwoven support fixed thereon. The base structure includes a first fabric layer and a second fabric layer, wherein at least the first fabric layer has longitudinal threads and transverse threads which intersect at intersecting points. The longitudinal threads and the transverse threads of the first fabric layer are integrally bonded to each other, in particular welded to each other, at at least 5% of the intersecting points, in particular at at least 10% of the intersecting points.