What is a spiral fabric?
A spiral fabric is an industrial belt assembled from monofilament spirals joined by hinge pins (cross yarns through the adjacent loops) — not woven on a loom, but built like a chain of springs. The structure runs true without tracking guides, drains fast, cleans easily and can be repaired link by link on the machine. That is why it is the workhorse belt of dryers and belt press filters alike.
Two families: without and with filler yarns
The same platform serves two opposite duties, tuned by filler yarns — extra monofilaments inserted into the spiral loops:
- Without filler yarns — the spiral stays open (up to ~900 CFM). Air passes freely: ideal for dryer fabrics, through-air drying and conveying.
- With 1–5 filler yarns — density rises and air permeability drops (into the 20–150 CFM band). Fines stay on the belt: ideal for filter duties on belt press filters.
Round or flat filler yarns?
- Round monofilament fillers maximize open area and CFM, keeping drainage channels clear longer.
- Flat monofilament fillers give a smoother surface and better fines retention while still breathing well — the usual choice for juice and palm oil pressing.
Naming: spiral fabric, spiral dryer fabric, spiral belt
Spiral fabric is the family name and matches the structure you see in image searches. By duty: spiral dryer fabric (drying, no fillers) and spiral press filter belt / dewatering belt (filtration, with fillers). Spiral belt alone is a common alias — but be aware it is also used for the metal and plastic spiral-tower conveyor belts of the food freezing industry, a different product entirely. When searching or specifying, add the duty word: dryer or press.
Spiral vs woven dryer fabric
Spirals drive efficiency upstream: in the wet, high-air zones their openness moves the most air. Woven fabrics run smoother and more stably at the hottest, fastest positions. The field rule — spirals early, wovens late — holds for most paper, panel and nonwoven dryers.
How to specify a spiral fabric
- Duty first: drying/conveying (no fillers) or filtration (1–5 fillers).
- Then permeability target in CFM — we tune filler count and cross-section to hit it.
- Material: PET standard; PPS for around 240 °C long-term duty.
- Seam: spiral pin seam standard; endless on request.
- Edges: sealed, welded or reinforced to your machine.
Aurora SP series covers both families from one weaving platform — see the spiral fabric overview, compare with woven dryer fabrics, or explore our woven press filter belts.