Woven vs. Spiral Dryer Fabrics: Where to Use Which, and Why
- Snehes Dasgupta
- Nov 24
- 3 min read
In the high-stakes dryer sections of paper machines, selecting and positioning the right fabric—woven or spiral—can significantly enhance drying efficiency, sheet quality, and operational uptime. Woven fabrics excel in controlled contact and surface finish, while spirals prioritize permeability and durability in demanding conditions. This comprehensive guide combines insights from our recent LinkedIn series to help technical teams optimize placements, drawing on proven applications for various paper grades and machine configurations. Whether you're running newsprint, board, or coated papers, understanding these suitabilities minimizes defects like marking or uneven drying while extending fabric life.
Woven Dryer Fabrics: Precision for Finishing and Stability:
Woven dryer fabrics, constructed from monofilament polyester (PET) yarns—often hydrolysis-resistant for steam-exposed zones—offer predictable contact areas and dimensional stability, making them ideal for positions where sheet support and printability are paramount. They are best positioned in later dryer groups, finishing sections, and for calendered or fine printing grades, where uniform deflection prevents micro-marking and ensures gloss.
Mono-Tier (Single-Layer) Woven: Smooth Surfaces for Print-Sensitive Runs
Mono-tier woven fabrics, featuring flat monofilament yarns in a single-layer design, deliver the smoothest paper-side contact and highest contact area (>30%), minimizing air carry and flutter in high-speed operations (>800 m/min). These are optimal for final dryer groups and coated/print-sensitive positions, such as lightweight office papers or specialty grades, where surface quality drives end-use performance. The dual-warp system enhances security against breaks, but monitor seams for marking risks—position them away from sensitive cylinders or opt for reinforced designs. In hydrolysis-prone pockets (>140°C), hydrolysis-resistant PET extends life by 20-30%, reducing brittleness from steam vapor.
Multi-Tier (Multi-Layer) Woven: Resilience in High-Load Zones
Multi-tier constructions, with layered warps and wefts for tailored permeability (200-950 CFM), provide superior airflow and robustness in earlier or mid-dryer groups handling high-moisture or board grades. Their resilience absorbs tension fluctuations, optimizing ventilation in grouped cylinders (<600 m/min), but they clog faster upstream with contaminants like pitch or stickies—reserve for downstream after cleaning stations or use anti-adhesive filaments in recycled furnishes. For extreme conditions, blend with polyphenylene sulfide (PPS) yarns, which resist hydrolysis up to 285°C and maintain flexibility under thermal attack.
Key caveat: Weave intricacy can trap debris, so pair with online cleaning systems for recycled runs to sustain permeability.
Spiral Dryer Fabrics: Durability and Flow for Early-Stage Demands:
Spiral dryer fabrics, formed from interlocking monofilament coils for seamless-like behavior, shine in high-permeability needs and distortion tolerance, suiting earlier/middle groups or high-speed machines (>600 m/min). Their open structure (up to 900 CFM) supports rapid moisture removal and wad-handling, reducing energy by 10-15% via better pocket ventilation, but select yarn types carefully for surface demands.
Round Monofilament Fillings: Maximum Openness for Moisture-Heavy Sections
Round monofilament spirals maximize open area and CFM, keeping channels clear longer under contamination—ideal for middle dryer groups, high-moisture removal zones, or high-speed web handling in newsprint/board production. The coiled geometry tolerates misfeeds and misalignment better than woven seams, with uniform body-seam strength preventing breaks. Use hydrolysis-resistant PET for standard setups or full PPS for hot pockets (>150°C), ensuring longevity in abrasive, wad-prone environments.
Flat Monofilament Fillings: Balanced Finish in Transitional Positions
Flat monofilament spirals offer smoother contact than round variants while retaining high permeability, making them suitable for mid-to-late dryer sections where heat transfer and finish matter without sacrificing airflow. Enhanced wear resistance suits high-speed un-run draws, but avoid coarse loops over final print cylinders to prevent marking—flat fillings mitigate this for coated grades. PPS construction provides superior hydrolysis resistance, ideal for chemical-heavy or high-temp runs.
Operational tip: Verify machine geometry before installs; older setups may require edge adaptations for optimal fit.
Woven vs. Spiral: Tradeoffs and Placement Strategy
Fabric Type | Best Positions | Strengths | Limitations | Material Options |
Woven Mono-Tier | Final groups, coated/print grades | Smooth contact, high gloss, low marking | Seam vulnerabilities, lower permeability | Hydrolysis-resistant PET |
Woven Multi-Tier | Early/mid groups, board/high-moisture | Resilience, tailored airflow (200-950 CFM) | Clogging in contaminants, seam marking | PET/PPS blends |
Spiral Round Mono | Middle groups, high-speed/moisture zones | Max CFM, wad tolerance, open structure | Coarser surface | PET or PPS |
Spiral Flat Mono | Mid-late groups, balanced finish needs | Wear resistance, heat transfer | Potential coarseness if not tuned | 100% PPS for extremes |
Wovens prioritize finish in downstream stability; spirals drive efficiency upstream. Hybrid strategies—e.g., spirals early, wovens late—optimize across grades.
PMC Centre provides unbiased consultancy to optimize Paper Machine Clothing performance—independent of fabric sales. Our data-driven expertise helps resolve issues like dryer fabric placement with precision.
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