Pneumatics
Compressor & Buffer Tank Sizing
Determine the required compressor capacity and buffer vessel volume for a pneumatic installation.
Units:
A star-delta starter needs ≈15 seconds (0.25 min) before the compressor delivers air. Add 10–25% margin for future expansion and leakage. Leakage alone typically accounts for 20–30% of total production — fix leaks before over-sizing the compressor.
V_tank [l] = Q_total [nl/min] × t_startup [min] × (P_work + 1) / ΔP × 1.05
Input
Total air demand iSum of all consumer flow demands at working pressure in normal-litres per minute.
nl/min
Capacity margin iAdditional reserve for future expansion, leakage and unforeseeable peak demand. Typically 10–25% of total demand.
nl/min
Tank max pressure (cut-out) iMaximum pressure in the receiver tank (compressor cut-out pressure). Typically 8–12 bar.
bar
Pressure band ΔP iDifference between cut-in and cut-out pressure. The compressor restarts when pressure drops by ΔP. Typically 2–4 bar.
bar
Working pressure iRequired working pressure at the installation in bar.
bar
Compressor startup time iTime before the compressor delivers compressed air after starting. Star-delta start: 0.25 min (15s). Direct-on-line: 0.05 min (3s).
min
Result
Required compressor capacity [nl/min]
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Calculated buffer volume [litre]
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Recommended tank size [litre]
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Recommended tank size [m³]
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