The primary filter is a primary filtration device for air conditioning and air purification systems, mainly used to filter dust particles larger than 5 μ m. Divided into grades G1 to G4. Common styles include plate type, folding type, and bag type, as well as types such as activated carbon filters and high-temperature resistant coarse efficiency filters.
The primary filter adopts the principle of physical filtration, intercepting large particulate pollutants through filter material fibers. The outer frame material usually includes paper frame, aluminum frame, galvanized iron frame, etc., while the filter material includes non-woven fabric, nylon mesh, activated carbon filter material, metal mesh, etc
Details:
Filter object: Large particulate pollutants (dust, hair, fibers, willow catkins, gravel) ≥ 5 μ m
Efficiency level: G1-G4 (EN 779); Weight efficiency of 20% -90%
Structural form: Plate type, folding type, bag type
Frame material: paper frame, aluminum frame, galvanized iron frame, stainless steel
Filter materials: non-woven fabric, nylon mesh, metal wire mesh, polyester fiber
Core Features
Low resistance, high air volume, and economical price
Large dust holding capacity, short replacement cycle (1-3 months)
Simple structure, easy installation and maintenance.
Application
Central air conditioning fresh air pre filtration for large buildings (shopping malls, airports, office buildings);
Industrial ventilation system, primary filtration of clean room return air;
Front end protection for household/commercial air conditioners, air compressors, and fan coil units;
Air purification for ordinary factories, warehouses, and computer rooms.
Air Filter Product Parameters
| Parameter | Primary Filter | Medium Efficiency Bag Filter | HEPA Filter | ULPA Filter |
| Filtration Accuracy | ≥5μm large particles | 1–5μm medium particles | ≥0.3μm fine particles | ≥0.12μm nano-scale particles |
| Efficiency Grade | G1–G4 | F5–F9 | H13–H14 | U15–U17 |
| Typical Efficiency | 20%–90% (gravimetric method) | 45%–97% (counting method) | 99.97%–99.995% | ≥99.9995% |
| Filter Media | Non-woven fabric, metal mesh | Non-woven fabric, fiberglass | Ultra-fine glass fiber | Borosilicate glass fiber |
| Initial Resistance | ≤50Pa | ≤150Pa | 200–250Pa | 250–350Pa |
| Service Life | 1–3 months | 6–12 months | 1–3 years | 2–5 years |
| Main Function | Pre-filtration, rear-end protection | Intermediate filtration, dust removal | Terminal fine filtration, bacteria removal | Ultra-clean filtration, nano-particle removal |





