Contaminants in Air
Atmospheric air brings unwanted "gifts" to your compressed air system.
The Three Categories
| Contaminant | Source | Problem |
|---|---|---|
| Water | Atmosphere + compression | Corrosion, bacteria, equipment damage |
| Particles | Atmosphere + wear | Abrasion, blockages, contamination |
| Oil | Compressor + atmosphere | Contamination, residue, membrane damage |
Solid Particles
Atmospheric air typically contains:
- 140 million particles per m³
- 80% are smaller than 2 microns (invisible)
- Includes: dust, metal oxides, pollen, fibers
Effect of compression
10:1 Compression = 10x Concentration
140 million/m³ → 1,400 million/m³
Oil and Vapors
Oil sources
- Compressor lubricant (in lubricated systems)
- Atmospheric vapors (traffic, nearby industries)
- Degradation of seals and materials
Forms of oil
| Form | Size | Removal |
|---|---|---|
| Liquid (droplets) | > 1 μm | Separator, filter |
| Aerosol (mist) | 0.01 - 1 μm | Coalescing filter |
| Vapor (molecular) | < 0.01 μm | Activated carbon |
Concentration from Compression
Everything multiplies:
| What enters | 8:1 Compression | What exits |
|---|---|---|
| 1 mg/m³ particles | × 8 | 8 mg/m³ |
| 50% RH | → 100% | + condensate |
| 0.1 mg/m³ hydrocarbons | × 8 | 0.8 mg/m³ |
That's why location matters
Locate the air intake away from:
- Vehicle exhausts
- Chimneys
- Dusty areas
- Hot air from equipment