Paper Machine Clothing Non-Cylindrical Through-Channels
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Solution Overview
Problem
Existing paper machine clothing technologies face limitations in fiber retention, permeability, and quality of the fiber web produced, with room for improvement in these characteristics.
Innovation Solution
The development of paper machine clothing with non-cylindrical through-channels that have a changing cross-sectional area from the upper to the lower side of the substrate, featuring a more elliptical shape near the upper side and a circular or more elliptical shape near the lower side, allowing for anisotropic properties and enhanced stress resistance in the machine direction, while maintaining or increasing the open area on the upper side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cylindrical through-channels with constant cross-sectional area are used, then the manufacturing process is simple, but the fiber retention and dewatering capabilities are limited
Solution Approach 1:
The patent applies parameter changes by varying the cross-sectional area of through-channels along their length, transitioning from a constant area (cylindrical) to a variable area (tapered) configuration. Specifically, the through-channels have a larger cross-sectional area at the upper side (paper side) and a smaller cross-sectional area at the lower side (machine side), creating a tapered geometry that optimizes both fiber retention and dewatering performance while remaining manufacturable through standard laser drilling processes
2Reliability
If the open area on the upper side is increased to improve permeability, then the dewatering capability improves, but the structural integrity may be compromised
Solution Approach 1:
The patent applies local quality by creating through-channels with non-uniform cross-sectional area distribution, where the upper portion (at the paper side) has a larger area to maximize open area and permeability for effective dewatering, while the lower portion (at the machine side) has a smaller area to maintain structural integrity and support the fiber web. This localized variation in channel geometry allows each region to be optimized for its specific functional requirement
3Productivity
If the through-channels have a tapered shape with smaller area at the middle region, then fiber retention improves, but the manufacturing complexity increases
Solution Approach 1:
The patent implements parameter changes by defining a specific tapered geometry for the through-channels where the cross-sectional area varies continuously or in steps from the upper side to the lower side. The channel area is largest at the upper side, reduces through the middle region, and maintains a smaller area at the lower side. This geometric parameter variation enhances fiber retention by creating a gradual transition that prevents fiber loss while remaining compatible with laser drilling manufacturing processes
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 configuration improves the quality of the fiber web by enhancing fiber retention and dewatering capabilities, allowing for higher stress resistance in the machine direction and increased open area on the upper side without compromising structural integrity.
Implementation Method 1
The substrate is perforated using a laser beam LB from a laser that is connected to a controller so as to drill a plurality of discrete through-channels 30′ into the substrate 20′
Data Source
AI summary
A paper machine clothing has a substrate with an upper side, a lower side, two lateral edges and a usable region between the two lateral edges. The usable region is formed with a plurality of through-channels extending through the substrate and connecting the upper side with the lower side. The through-channels are non-cylindrical with a cross sectional area becoming smaller when going in a thickness direction of the substrate from the upper side to a middle region of the substrate between the upper side and the lower side, wherein a shape of the cross sectional area of at least one through-channel, preferably of all through-channels, of the plurality of through-channels changes proceeding in the thickness direction of the substrate from the upper side to the lower side.