Piston compressor with receiver
A reciprocating compressor mounted on an air receiver, for intermittent duties — tyre inflation, small air tools, workshop blow-down. Cheap to buy and deliberately not built to run all day.
Features
- Duty cycle is the limiting specification: many machines are rated for 50 to 60 % running time per hour and overheat above it.
- The receiver, not the pump, supplies short peaks, so receiver volume is the figure that decides whether the tool stutters.
- Two-stage pistons reach 10 bar and above; single-stage machines stop being efficient beyond about 8 bar.
- Belt-driven cast-iron pumps at low speed last far longer than direct-drive aluminium ones and are worth the difference on daily use.
- The receiver is a pressure vessel with a drain that has to be opened on a schedule, and corrosion from standing condensate is what ends its life.
- Pulsation makes a piston machine unsuitable for instrument air without treatment.
Specifications
| Figure | Typical range | Unit | Why it matters |
|---|---|---|---|
| Free air delivery | 200 - 1 200 | l/min | The honest output figure, not displacement. |
| Working pressure | 8 - 11 | bar | Two-stage machines are needed above about 8 bar. |
| Receiver volume | 90 - 500 | l | Buffers peaks and sets motor start frequency. |
| Permitted duty cycle | 50 - 70 | % | Exceeding it is the commonest cause of failure. |
| Motor rating | 1.5 - 7.5 | kW | Sizes the supply and starter. |