Navigating Dryer Fabric Challenges: Key Pain Points and Solutions for Woven and Spiral Designs in Paper Machines
- Snehes Dasgupta
- 5 days ago
- 3 min read
In today's high-speed paper machines processing high-fines and recycled furnishes, the dryer section remains a critical bottleneck for efficiency and profitability. Woven and spiral dryer fabrics each offer unique advantages—such as stability and permeability—but mismatching them to machine positions, heat loads, or contaminants can lead to sheet defects, elevated energy use, and frequent downtime. Drawing from recent industry insights, this post outlines the top pain points for both fabric types, paired with practical solutions to enhance runnability and extend service life.
At PMC Centre, we provide unbiased, data-driven consultancy to optimize Paper Machine Clothing (PMC) performance, independent of fabric sales. Our expertise helps mills resolve these issues precisely, minimizing costs and boosting output.
Pain Points and Solutions in Woven Dryer Fabrics:
Woven designs, including flat-warp, multi-tier, and unifier constructions, excel in surface contact and stability but are prone to seam vulnerabilities and contamination in upstream groups.
1. Seam Thickness and Uneven Air Permeability Leading to Sheet Marking:
Thick or mismatched seams disrupt airflow, causing up to 20–30% permeability variance from the fabric body and resulting in marking or early failure under high tension. This is exacerbated in lightweight grades at speeds over 600 m/min.
Solution: Opt for low-profile, straight-yarn seams verified for seam-to-body CFM matching via ultrasonic welding or advanced seaming techniques to ensure uniform drying and non-marking performance. Regular permeability profiling during installation can prevent imbalances.
2. Contamination Buildup Causing Rapid Permeability Loss:
Flat-yarn wovens in upstream positions plug quickly with stickies, wax, adhesives, and fiber debris from recycled furnishes, dropping permeability by 20% within months and reducing drying efficiency by 10–15%.
Solution: Deploy modern online cleaning systems like high-impact oscillating showers or low-pressure hot water jets before woven sections, especially for recycled grades, to maintain 90% openness and avoid over-drying.
3. Hydrolysis and Thermal Degradation Resulting in Strength Loss:
Even hydrolysis-resistant PET degrades under prolonged moisture and heat above 120°C, leading to brittleness, chain scission, and reduced tensile strength in steam pockets.
Solution: Specify PPS yarns for high-temperature or extended-run positions, offering resistance up to 185–200°C and minimizing hydrolysis risks while preserving flexibility.
4. Fabric Distortion (Bowing/Narrowing) Causing Misalignment and Edge Wear:
Improper roll alignment, tension variations, or wrap angles induce bowing, uneven permeability, and edge wear, shortening life in high-tension environments (>4 kN/m).
Solution: Correct machine geometry and tension via audits, or select multi-tier/unifier constructions for enhanced dimensional stability and diagonal resistance to distortion.
5. High Cleaning Demand in Contaminant-Rich Zones:
Fine flat-warp weaves clog rapidly in early dryers with pitch and adhesives, increasing shutdowns and maintenance frequency in sticky furnishes.
Solution: Reposition wovens downstream or incorporate anti-sticky filaments/coatings like CleanTec for reduced adhesion, combined with robust online showers to cut cleaning cycles by 30–50%.
Pain Points and Solutions in Spiral Dryer Fabrics:
Spiral fabrics provide seamless runnability and high permeability for kraft and newsprint, but challenges arise in high-speed or legacy setups, particularly with fluttering and contamination.
1. Compatibility Issues on Older or Non-Standard Machines:
Non-uniform cylinder geometry or outdated guides cause misalignment and shortened life in legacy mills, amplifying distortion under tension.
Solution: Conduct full machine audits for dryer-can geometry and edge guides before conversion; pilot small runs or retrofit guides to ensure fit and stability.
2. Balancing Permeability vs. Contact Area:
High-airflow large-loop or round-yarn spirals (450–900 CFM) boost evaporation but reduce contact uniformity (<30%), leading to marking in sensitive grades at >800 m/min.
Solution: Use flat-yarn spirals or optimized loop/yarn combos for mid-to-late groups, increasing contact to 37% while controlling CFM for uniform heat transfer and sheet finish.
3. Dimensional Instability or Increased Thickness:
Thicker profiles and tension variations cause stretch, elongation, or uneven running, especially in humid/high-heat zones up to 150°C.
Solution: Incorporate reinforced edges and PPS yarns (up to 185°C tolerance) for superior stability; monitor installation tension and perform periodic edge inspections to prevent bowing.
4. Cleaning and Maintenance Risks Under Heavy Contamination or Sticky Furnish:
Deposits like pitch, glue, and coatings clog openings in recycled/adhesive-rich runs, impairing permeability despite seam-free design.
Solution: Implement a formal regimen with periodic chemical/shower-based cleaning and proper rinsing; avoid harsh caustics to preserve polymers and maintain openness.
By addressing these pain points through targeted fabric selection and maintenance, mills can achieve 15–20% energy savings and extend fabric life amid 2025's sustainability pressures. PMC Centre's consultancy and AI tools empower you to navigate these challenges independently.
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Sources:
[4]: https://www.astenjohnson.com/media/1761/expertip-1-cleaning-and-conditioning-of-dryer-fabrics.pdf
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