Compressor
Impeller accelerates air radially; a diffuser converts velocity to pressure. Oil-free by design, high CFM.
Typical range
300–10,000+ HP, 100–150 PSIG (single to multi-stage)
Best for
Large-scale continuous plant air, oil-free air, high CFM.
Operating principle
An impeller accelerates air radially (dynamic/kinetic compression); a diffuser converts velocity to pressure. Multiple stages reach higher pressures. There are no internal rubbing parts in the compression path.
Efficiency notes
High efficiency at full load (large CFM); poor at part load — surge and stall. Most efficient at high, steady flow (>1,000 CFM).
Selection guidance
Large plant air (1,000–25,000+ CFM), oil-free by design, continuous duty. Avoid for variable or low flow — turndown is limited by the surge line.
Components
- Impeller(s)
- Diffuser
- Inlet guide vanes
- Coolers (inter/after)
- Surge control valve
- Gearbox (high-speed)
- Motor or turbine drive
Common issues
- Surge → low flow, inlet filter restriction, controls failure
- High vibration → bearing wear, rotor imbalance
- Oil leak from gearbox → seal failure
Maintenance
- Daily: monitor vibration, temps, surge margin
- Vibration analysis quarterly
- Inlet filter change on differential, not schedule
- Gearbox oil per OEM (typ. 4,000–8,000 hrs)
Field tips
- Surge damages the machine — never let flow drop below the surge line without controls
- Inlet guide vanes / blow-off valves manage turndown
- Dry oil-free — no separator oil to manage