Industrial Multilayer Fabric Narrower Weft Sandwich Knuckle
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Solution Overview
Problem
Industrial papermaking fabrics face challenges in maintaining rigidity, wear resistance, and joining strength due to reduced weft density and yarn diameter, which affects dehydration properties and stability during high-speed paper machine operations.
Innovation Solution
The arrangement of narrower wefts with a smaller diameter between lower side wefts to sandwich warps, enhancing weaving strength, size stability, and joining strength by forming a knuckle structure that fixes warps and reduces undesirable yarn movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of lower side wefts is reduced to improve dehydration property and rigidity, then dehydration efficiency improves, but fabric strength and joining strength deteriorate
Solution Approach 1:
The patent applies local quality by differentiating the configuration of wefts in different regions of the fabric. Specifically, the number of lower side wefts is reduced in the dehydration zone to improve water removal efficiency, while the number of upper side wefts is increased to maintain fabric strength and joining strength. This regional differentiation allows each zone to be optimized for its specific function without compromising overall fabric performance.
2Shape
If yarn diameter is reduced to thin wire thickness and improve surface smoothness, then surface property improves, but joining strength and fabric stability deteriorate
Solution Approach 1:
The patent applies local quality by using different yarn diameters in different layers of the fabric. The upper side yarns are made with smaller diameter to achieve smooth surface properties and prevent wire mark transfer to paper. The lower side yarns are made with larger diameter to provide sufficient joining strength and stability in the dehydration zone. This layered differentiation resolves the contradiction between surface smoothness and joining strength.
3Strength
If wefts are made responsible for wear by creating long crimp structure, then wear resistance improves, but rigidity deteriorates due to decreased confounding portions
Solution Approach 1:
The patent applies local quality by assigning different functions to wefts in different regions. The upper side wefts are configured with long crimp structures to provide wear resistance where the fabric contacts rollers. The lower side wefts are reduced in number to maintain rigidity and prevent excessive yarn movement in the dehydration zone. This regional functional differentiation allows wear resistance and rigidity to be optimized simultaneously.
Solution Approach 2:
The patent segments the fabric into functionally distinct zones with different weft configurations. The upper side is segmented to have more wefts for wear resistance, while the lower side is segmented to have fewer wefts for rigidity. This segmentation allows each zone to be independently optimized for its specific mechanical requirements.
4Duration of action of stationary object
If the fabric is made endless by joining conventional methods, then continuous operation is enabled, but joining strength decreases due to reduced yarn diameter and fewer confounding portions
Solution Approach 1:
The patent applies local quality by concentrating confounding portions and stronger yarns at the joining zone of the endless fabric. The joining area is locally reinforced with increased weft density and larger diameter yarns to ensure strong connections. The rest of the fabric maintains the optimized configuration with reduced lower side wefts for dehydration efficiency. This local reinforcement at the joining zone resolves the contradiction between continuous operation and joining strength.
Data Source
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AI summary
In an industrial multilayer fabric, narrower wefts of a small diameter are placed between lower side wefts so as to sandwich a knuckle formed by a lower side warp on the lower surface side of the fabric. The industrial fabric is obtained by stacking at least upper side wefts and lower side wefts one after another and weaving these wefts with warps (3d), wherein narrower wefts (4'g) having a smaller diameter than that of the lower side wefts (5'd) and forming a shorter crimp than that formed by the lower side wefts (5'd) on the lower side surface are arranged between the lower side wefts; and at a knuckle portion formed by warps (3d) passing under one or two successive lower side wefts, the narrower wefts form a crimp passing under lower side warps so as to sandwich, from both sides, one knuckle or two knuckles formed by two adjacent warps under two adjacent wefts.