Why two stages
A single stage asked to reach 20 or 30 bar works against a high pressure ratio, which raises discharge temperature and reduces efficiency. Two stages split that ratio, cool the air between them, and compress again. The intercooling is the mechanism: removing heat before the second stage reduces the work required and keeps the oil and seals inside their temperature range.
What we build
Two-stage high pressure machines in our catalogue run from 110 kW to 250 kW class with working pressures covering 15, 20 and 30 bar, in both screw and high pressure configurations depending on the duty. The family is separate from the standard band because the applications - bottle blowing, laser assist, high pressure processes - have different duty cycles.
| Selection input | What it changes |
|---|---|
| Final pressure | Sets the second stage ratio and the intercooler duty |
| Flow at pressure | Sets the frame size; quoted at pressure, not at a nominal figure |
| Duty cycle | Blowing is continuous; intermittent duties may not justify two-stage |
| Cooling | Water cooling is common at these sizes; confirm site supply and quality |
| Air quality | High pressure drying and filtration are part of the system, not accessories |
Installation considerations
- Foundation and lifting - larger frames need a defined base and a checked route into the building.
- Heat rejection - intercooler and aftercooler both reject heat; the room has to be able to remove it.
- Piping rating - the downstream system must be rated for the working pressure, including fittings and hoses.
- Storage - a receiver rated above working pressure, sized for the demand cycle.
Service focus
Two-stage machines add an intercooler and a second rotor set to the maintenance picture. Intercooler fouling shows up as rising second-stage discharge temperature and falling efficiency, so cooling water quality and cooler cleaning belong on the schedule alongside oil and separator changes.
Browse the range on the two stage high pressure screw air compressor collection page.
Tell us the working pressure, flow and site conditions and we will propose a configuration. Contact OPPAIR.