Compressor
Two figure-eight lobes move air without internal compression. Low pressure, high flow.
Typical range
1–500 HP, to ~15 PSIG (1 bar) differential; as vacuum to ~0.5 bar
Best for
Aeration, conveying, blower service, low-pressure high-flow, vacuum boosters.
Operating principle
Two figure-eight lobes rotate without contact, trapping and moving air from inlet to outlet. There is no internal compression — the pressure rise comes from system backpressure. Low pressure, high flow.
Efficiency notes
Efficient at low pressure ratios (to ~15 PSIG). No internal compression means power rises with pressure. Best for low-pressure, high-flow duty.
Selection guidance
Aeration, pneumatic conveying, vacuum boosters, aeration. Low pressure, high CFM.
Components
- Twin lobes (2 or 3 lobe)
- Timing gears
- Inlet/outlet silencers
- Drive coupling
- Relief valve (system)
Common issues
- Pulsation/noise → 3-lobe reduces vs 2-lobe; add silencers
- Overheating → high discharge temp at high pressure
- Lobe contact → timing-gear/bearing failure
Maintenance
- Grease bearings per OEM
- Check timing-gear backlash
- Silencer cleaning; pulsation-dampener service
Field tips
- 3-lobe rotors pulse and run quieter than 2-lobe
- Add inlet/outlet silencers for noise and pulsation
- No internal compression — power climbs with system pressure