For 60-70% of industrial filter press duties, off-the-shelf cloth works fine. For the other 30-40% — unusual chemistry, very fine particles, sticky cake, or extreme temperature — only custom filter cloth delivers reliable performance. The custom-specification process has seven key parameters that the cloth maker needs to know.
The Seven Custom-Cloth Parameters
1. Fiber Material
PP, polyester, nylon, PTFE, or a blend. Chosen based on chemistry compatibility, operating temperature, and abrasion resistance.
2. Yarn Type
Monofilament (single fiber, best release), multifilament (multiple fibers twisted, balance), or staple (short fibers spun, best retention). Each gives a distinctive cake formation and release behavior.
3. Weave Pattern
Plain, twill, satin, or specialty weaves. Affects strength, air permeability, and cake-release characteristics.
4. Air Permeability (the practical micron rating)
Measured in l/dm²/min @ 200 Pa. Lower values = finer cloth. Typical industrial range: 5-100. Specifying this directly is more meaningful than nominal micron rating.
5. Edge Treatment
The cloth needs an edge that seats properly in the plate hanging loops, with reinforcement to prevent tear-out. Options include rope edge, sewn binding tape, hem fold, or heat-bonded edge.
6. Center Hole & Feed Port Cuts
For chamber and membrane plates, the cloth needs precise cutouts for the central feed eye and (sometimes) corner outlet ports. Cutouts must align perfectly with plate hole centers — a 2-3 mm offset causes leakage and blowout.
7. Surface Treatment
Calendered (smoothed for better release), heat-set (dimensional stability), singed (anti-fuzz), or specialty coatings like PTFE impregnation for chemistry boost or silicone for cake release.
When You Definitely Need Custom Cloth
- Slurry chemistry mixes hot acid + chloride + organic solvent — single off-the-shelf cloth can’t handle all three
- Particle size below 2 µm — needs ultra-fine weave or coated cloth
- Sticky cakes (gold concentrate, kaolin) — needs specific surface treatment
- Non-standard plate size or shape — custom cut and edged
- Conductive cloth required (explosive atmosphere) — needs conductive yarn blend
- Food-grade or pharma traceability — needs FDA/EU material certificates
Common Custom-Cloth Applications
- Specialty chemical — solvent + acid + temperature combinations
- Pharmaceutical clarification — sub-micron filtration with traceability
- Catalyst recovery — extreme retention efficiency for valuable solids
- Battery and lithium processing — chemistry resistance to LiOH and solvent
- Mining concentrate with cake wash — specific release + retention balance
Specifications & Customization Options
- Materials: PP, polyester, nylon, PTFE, cotton, conductive blends
- Plate sizes: Any from 470 mm to 2000 mm square (and custom geometries)
- Quantity: MOQ from 50 m² for standard materials, 200 m² for specialty
- Lead time: 2-3 weeks for standard custom; 4-6 weeks for specialty treatments
- Certifications: Food-grade FDA, EU 10/2011, USP Class VI on request
FAQs
What’s the price premium vs standard cloth? Typically 20-50% above standard for moderate customization (edge, cut, weave); 100-300% for specialty materials like PTFE or specialty coatings.
Can I send you a sample to match? Yes — Senjie does reverse-engineering of legacy cloth specs. Send 0.5 m² of the original cloth and we can match material, weave, and air permeability within 2-3 weeks.
How do I trial a custom cloth? We typically send a 4-plate sample set (8 m² total) for installation in your press for 5-10 cycles of evaluation. Detailed test reports help refine the spec before bulk order.
Need custom cloth? Contact Senjie with your slurry chemistry, current cloth failure mode (if any), plate size, and operating temperature — we’ll develop a custom spec from our cloth catalog.