Primary Pre-Filters
Primary pre-filters serve as the first line of defense in air purification systems, primarily capturing large particles ≥5μm (such as dust, pollen, and hair) to protect downstream medium- and high-efficiency filters, extending their lifespan. Their core functions include:
- Coarse Filtration: Made from materials like non-woven fabric, nylon mesh, or metal mesh, with filtration efficiency of 30%-90% (for 5μm particles).
- System Protection: Reduces load on medium/high-efficiency filters, lowering maintenance costs.
Types & Structure
- By Filtration Grade
- G1-G4: European standard EN779 classification, with G4 achieving 70%-90% efficiency (5μm).
- By Filter Material
- Reusable: Metal mesh or nylon mesh (e.g., aluminum-frame pre-filters).
- Disposable: Non-woven fabric or synthetic fiber (e.g., flat panel pre-filters).
- By Design
- Flat Panel: Low cost, suitable for HVAC systems.
- Pleated: Larger filtration area, higher dust holding capacity.
- Pocket: Higher efficiency, ideal for pre-filtration stages.
Key Parameters & Selection
| Parameter |
Typical Value |
Application |
| Filtration Efficiency |
G4: 70%-90% (5μm) |
Office buildings, shopping malls |
| Initial Resistance |
30-50Pa |
Industrial plants, food processing |
| Dust Holding Capacity |
High (reusable types perform better) |
High-dust environments (e.g., painting workshops) |
| Temperature Resistance |
-40℃~70℃ (special models up to 250℃) |
High-temperature industrial settings |
Installation & Maintenance
- Installation Notes
- Match system airflow (recommended velocity: 1-3 m/s).
- Check sealing (e.g., double-lip seal design).
- Maintenance Schedule
- Commercial spaces: 3-6 months; industrial: 1-3 months.
- Replacement criteria: Pressure drop reaches 2-3× initial resistance or visible dust accumulation.
Typical Applications
- HVAC Systems: Pre-filtration for downstream protection.
- Cleanrooms: Air return filtration or pre-stage for HEPA filters.
- Industrial: Air compressor or gas turbine intake pre-filtration.
