Drying Wire Edge Welding for Paper Machine Fraying Prevention
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Solution Overview
Problem
Existing drying wires in paper or cardboard machines tend to fray at the edges due to their production process, leading to unraveling over time.
Innovation Solution
The edges of the planar textile structure are calendered by introducing energy to partially weld or interconnect yarns in a form-fitting manner, reducing thickness and permeability, thereby preventing fraying and unraveling without complex coatings or material changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the edges of the planar textile structure are left untreated in known drying wires, then the production process remains simple, but the edges tend to fray and yarns protrude over time, causing the planar textile structure to unravel
Solution Approach 1:
The edges of the planar textile structure are calendered in advance during the production process to pre-weld the yarns, preventing fraying and unraveling before the drying wire is put into service. This preliminary treatment ensures edge stability is built into the structure from the outset rather than requiring additional protective measures during operation.
Solution Approach 2:
The calendering process changes the physical and chemical parameters of the yarns at the edges by applying heat and pressure, causing the yarns to melt and weld together. This parameter change transforms the untreated, fray-prone edges into stabilized, fused edges that resist unraveling throughout the service life of the drying wire.
2Reliability
If complex coatings or material changes are applied to prevent edge fraying, then edge stability improves, but the production process becomes more complex and costly
Solution Approach 1:
The planar textile structure itself provides the means for edge stabilization through its own yarn material. The calendering process activates the thermoplastic properties of the existing yarns, causing them to weld together without requiring external coatings or additional materials. The structure serves its own edge protection needs through the inherent properties of its constituent yarns.
3Reliability
If the planar textile structure is calendered to weld yarns at the edges, then edge stability and durability improve, but the thickness and permeability of the clothing are reduced
Solution Approach 1:
The calendering process is applied selectively only to the peripheral regions along the edges of the planar textile structure, not to the entire surface. This localized treatment welds the yarns at the edges to prevent fraying while leaving the central, functional areas of the drying wire with their original thickness and permeability characteristics intact, maintaining the necessary properties for effective drying 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
This method effectively reinforces the edges, increasing extraction force by at least 10% and preventing unraveling, while allowing for simpler and more durable seam configurations, reducing permeability and thickness by up to 100% and enhancing edge stability, thus extending the service life and preventing damage to the machine.
Implementation Method 1
the planar structure is only calendered by introducing energy in peripheral regions which extend along the edges oriented in the machine direction and/or along the edges oriented in the machine cross direction, on account of which in the peripheral regions the MD yarns at least partially and/or in portions are welded to the CMD yarns
Implementation Method 2
the thickness and/or permeability of the clothing are/is reduced
Data Source
AI summary
A clothing, in particular a drying wire, for a machine for producing a fibrous web, such as a paper or cardboard web, is a planar textile structure from yarns which intersect in a machine direction and in a cross-machine direction. The planar structure has two edges oriented in the machine direction and two edges oriented in the cross-machine direction. The clothing is joinable along the edges oriented in the cross-machine direction in the machine so as to form an endless belt. The clothing is only calendered by introducing energy in peripheral regions which extend along the edges oriented in the machine direction and/or along the edges oriented in the machine cross direction, on account of which in the peripheral regions the MD yarns are welded to the CMD yarns, and the thickness and/or permeability of the clothing are/is reduced.