Two different ways to raise pressure
A screw compressor compresses continuously between rotating rotors. A piston compressor traps a fixed volume and squeezes it with a reciprocating piston. Both can reach high pressure; they behave very differently while doing it.
| Criterion | Screw | Piston |
|---|---|---|
| Duty | Continuous, stable flow | Intermittent or cyclic is normal |
| Pressure ratio | Best in the standard band; two stages for higher pressure | Comfortable at very high ratios, including multi-stage |
| Flow | High flow in a compact frame | Flow scales with cylinder size; large flows get bulky |
| Vibration and foundation | Rotating, low vibration | Reciprocating, needs a heavier foundation |
| Maintenance | Fewer wearing parts, longer service intervals | Valves and rings are consumables |
| Noise | Continuous, usually enclosed | Pulsating discharge, needs damping |
Where two-stage screw fits
For duties in the 20 to 30 bar class with continuous demand - bottle blowing is the classic case - a two-stage screw compressor is the usual choice. Splitting the ratio across two rotors with intercooling keeps discharge temperature and per-stage load in a range the machine can sustain, and the flow is steady, which the process wants.
Where piston still wins
Very high ratios, modest flow, and duties that run intermittently: these are piston territory. A piston machine can sit idle for hours and start into a high pressure duty without the concerns a continuously running screw package would have. For test benches, breathing air top-ups and similar low-flow high-pressure tasks, piston machines remain the practical answer.
What drives the decision
Start with flow at pressure and duty cycle. Continuous flow at moderate high pressure points to screw; low flow at very high pressure, or clearly intermittent operation, points to piston. Foundation, noise and maintenance labour then refine the choice.
Send us your working pressure, required flow and site conditions and we will propose a configuration. Contact OPPAIR.