Pneumatic Cylinder Air Consumption Calculator
Free air consumption of a pneumatic cylinder in NL/min and m³/h, plus the push force it develops.
Results
What this tool does
Compressed air is the most expensive utility in most factories, and a bank of cylinders cycling all shift is usually where it goes. The consumption is the swept volume of both strokes — the return stroke is smaller because the rod takes up room — multiplied by the cycle rate and by the compression ratio, because every litre at 6 bar started as about seven litres of room air.
Formula
consumption = (extend volume + retract volume) x cycles x (p + 1.013)/1.013
Variables
| Symbol | Meaning | Unit |
|---|---|---|
bd | Bore | mm |
rd | Rod diameter | mm |
st | Stroke | mm |
nc | Cycles per minute | 1/min |
pp | Pressure | bar |
QN | Free air consumption | NL/min |
QH | Free air consumption | m³/h |
VC | Air per cycle | L |
RA | Compression ratio | — |
FE | Force | N |
Worked example
- Bore50 mm
- Rod diameter20 mm
- Stroke200 mm
- Cycles per minute30 1/min
- Pressure6 bar
- Free air consumption150.07 NL/min
- Free air consumption9.004 m³/h
- Air per cycle0.7226 L
- Compression ratio6.9230
- Force1178.1 N
Limitations
- Mixing units is the most common source of error. Convert every input to the units shown next to each field before calculating.
- The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.
Frequently asked questions
What does NL/min mean?
Normal litres per minute: the volume the air would occupy once it is back at atmospheric pressure. A cylinder swallows less than a litre of compressed air per stroke, but the compressor has to draw in roughly seven times that from the room to make it at 6 bar. Compressor capacity is always quoted in free air delivery, so NL/min is the number to compare against.