Tighter environmental legislation and a more responsible approach to pollution have driven a shift to ever lower emissions from filter units.
A simple, cost-effective route is to reduce the coarseness of the fibers in the product in order to reduce the pore size of the felt. This then captures smaller dust particles with the benefit of lowered emissions. Regular polyester felt is 2 denier or larger, fine is 1½ and micro is 1 or under:
Fiber Diameter (µm) |
Felt Pore Size (µm) | |
|---|---|---|
| 2 denier | 14.3 | 28 |
| 1 denier | 10.1 | 20 |
Looking at these values it is easy to see why micro-denier is more efficient. Laboratory VDI data supports this 'theory'
2denier |
1.5 denier | |
|---|---|---|
| ΔP after Conditioning Pa | 60 | 90 |
| Dust Loading after Conditioning g/m² | 42.9 | 40.9 |
| Emissions during Conditioning mg/m³ | 2.28 | 0.84 |
| ΔP after Measuring Pa | 257 | 313 |
| Dust Loading after Measuring g/m² | 92.2 | 63.0 |
| Emissions during Measuring mg/m³ | 0.24 | 0.08 |
