KEVOS® MAKEOS · Pneumatics
Pneumatic Cylinder Air Demand
What reference-volume air demand does this cylinder cycle create?
Estimate ideal reference-volume consumption for a double-acting cylinder using absolute pressure and temperature.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Bore diameter | mm | Cylinder datasheet. |
| Rod diameter | mm | Rod diameter; single rod cylinder. |
| Stroke | mm | Travel per extension or retraction. |
| Supply gauge pressure | bar gauge | Working pressure at the cylinder. |
| Local ambient pressure | bar absolute | Local atmospheric pressure used to convert gauge to absolute. |
| Reference pressure | bar absolute | Pressure at which the reported litres are expressed. |
| Cylinder air temperature | °C | Average absolute-gas calculation temperature during filling. |
| Reference temperature | °C | Temperature at which the reported litres are expressed. |
| Complete cycles per minute | cycles/min | One extension plus one retraction is one complete cycle. |
Method and formulas
- Swept volume per full cycle (L) = [π × bore² / 4 + π × (bore² − rod²) / 4] × stroke / 10⁶.
- Absolute working pressure = gauge pressure + local ambient pressure.
- Reference litres/cycle = swept litres × (working absolute pressure / reference pressure) × ((reference °C + 273.15) / (cylinder °C + 273.15)).
- Multiply by complete cycles/min for reference L/min. At 50/20 mm, 100 mm stroke, 6 bar gauge plus 1 bar ambient and equal temperatures, the example uses 2.528982 reference L/cycle.
Limitations
- Ideal gas and swept chamber volumes only; tubing, dead volumes, leaks and valve losses are excluded.
- This is mean demand, not peak valve flow or compressor selection. Reference conditions must match when comparing air ratings.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- compressed air
- air consumption
- cylinder demand
Who it is for
- Automation engineers
- Maintenance teams
What you get
- Swept volume / complete cycle
- Working absolute pressure
- Reference volume / cycle
- Mean reference air demand
- Reference conditions
Interpreting the result
- Add measured leakage and auxiliary volumes, then check peak flow and pressure drop.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed CD pp. 3027–3036, 3421–3422. Topic reference; no source tables or recommended settings are reproduced.
- NASA Glenn: Equation of State (ideal-gas relationship) — https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/equation-of-state/
- Festo: Air consumption of cylinders — https://www.festo.com/ca/en/s/air-consumption
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