Pneumatic Cylinder Air Consumption Calculator
Estimate the compressed air used by a pneumatic cylinder or valve actuator, in free air terms, so you can size the compressor and air supply.
- Swept volume = (Abore + Aannulus) × stroke = 1.184 L
- Compression ratio = (P + 1.013) ÷ 1.013 = 6.922
- Free air = swept volume × ratio × cycles × qty = 81.96 L/min
Air Consumption Formula
Single acting: V = Abore × stroke
Free air = V × (Pg + Patm) ÷ Patm × cycles per minute
Abore is the piston area, Arod the rod area, Pg the supply gauge pressure and Patm = 1.01325 bar. One cycle is one extend and one retract stroke.
Worked example
A 63 mm bore, 20 mm rod, 200 mm stroke double acting cylinder at 6 barg making 10 cycles per minute uses about 1.18 L of swept volume per cycle, or 82.0 L/min of free air.
Frequently Asked Questions
What is free air?
Air at atmospheric pressure and inlet conditions. Compressor capacity is rated in free air, so consumption should be stated the same way.
Why is the return stroke smaller?
On the rod side, the rod occupies part of the cylinder, so less air is needed to retract.
How do valve actuators compare?
A piston actuator works the same way. For diaphragm or scotch yoke actuators use the manufacturer volume per stroke and the same compression ratio.
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