Technical Application Note
1. Application Points & Core Functions
1.1 Typical processes
- Powder drying: spray-dryers or fluid-beds for milk powder, protein powder, instant coffee, seasonings (chicken essence, flavours), nutritional supplements.
- Fruit/vegetable chips & tea: tray or tunnel dryers for apple chips, dried mushrooms, tea leaves.
- Cereals & snacks: ovens for breakfast flakes, biscuits, pet food.
1.2 Installation point
Mounted at the supply-air terminal of the drying equipment (dryer tower, oven). All heated air must pass through the filter before contacting the product.
1.3 Key functions
- Viable microbial barrier: removes bacteria, yeasts and moulds that could settle on moist product and cause spoilage or high colony counts.
- Particulate contaminant barrier: eliminates dust, pollen, fibres and insect fragments, avoiding foreign-body complaints.
- Quality protection: preserves colour/whiteness of sensitive powders (milk, protein) by removing sub-micron dust.
2. Why “High-Temperature” & “High-Efficiency”?
2.1 Temperature resistance (150 °C – 250 °C)
- Process air in spray dryers often enters at 150-250 °C; filter must withstand continuous duty without deformation or out-gassing.
- Construction: stainless-steel frame, high-temperature sealant, glass-micro-fibre media; FDA-compliant, odour-free.
2.2 High efficiency (H12-H14)
- Target contaminants ≥ 0.5 µm; H12 (≥ 99.5 % @ 0.3 µm) to H14 (≥ 99.995 % @ 0.3 µm) guarantees log-reduction.
- Meets GMP & HACCP requirements for “direct-contact” process air (critical control point).
- Mini-pleat separator-free benefits:
- Hygienic: no aluminium dividers → no corrosion, smooth surface, easy wipe-down.
- High dust holding → longer service life in dust-laden dryer air.
- Rigid under vibration common in drying equipment.
3. Industry-Specific Technical Requirements
3.1 Food-contact compliance
- All polymeric components certified to FDA 21 CFR or EU 10/2011; non-toxic, taste-free, corrosion-resistant.
- Surface finish Ra ≤ 0.8 µm, no pockets, full drainability.
3.2 Risk-based grade selection
- High-risk (infant formula): H14 + mandatory PAO/DOP leak test + 6-month change interval.
- Standard-risk (tea, cereals): H11-H13 acceptable per documented risk analysis.
3.3 Moist-heat tolerance
- Initial drying stage may see > 90 % RH at 80-120 °C; filter must withstand cyclic humidity without loss of efficiency or strength.
3.4 Validation & documentation
- Factory scan test + on-site PAO/DOP leak test ≤ 0.01 % penetration.
- Material certificates, test reports, change-out SOP provided for audit/traceability.
4. Value & Business Impact
- Food-safety baseline: prevents air-borne microbial & foreign-body contamination, protecting consumer health.
- Brand protection: avoids off-odours, discoloration, recalls, complaints.
- Regulatory/market access: prerequisite for ISO 22000, BRC, IFS and export to EU/US markets.
- Operational efficiency: reduces batch rejections and unplanned shutdowns, ensuring continuous, high-throughput drying.
Conclusion
High-temperature mini-pleat separator-free HEPA filters convert ordinary heated air into “clean hot air” and are the core hardware for achieving a hygienic drying stage. Correct selection and validation demonstrate a company’s commitment to food safety, quality and regulatory excellence, while safeguarding both product integrity and production economics.
Post time: Nov-13-2025