Coalescing filters remove oil as liquid droplets, but oil vapour passes through them as a gas. Activated carbon filters absorb that vapour, which matters in applications where even gaseous oil would contaminate the product or process.
When carbon filtration is required
- Food, beverage and pharmaceutical product-contact air
- Breathing air and medical systems
- Instrument air in sensitive processes
- Spray finishing where oil vapour causes defects
How it works
Air passes through a bed of activated carbon that adsorbs oil vapour and odours onto its surface. The carbon has a finite capacity, so the element must be replaced on schedule. Carbon filters are always fitted after coalescing filtration to keep liquid oil from saturating the bed.
Placement and maintenance
Fit the carbon filter as the final stage at the point of use, after the coalescing filter and dryer. Monitor the element life and replace it before breakthrough, because once the carbon is saturated, oil vapour passes straight through.