The accumulator sizing calculator computes the required accumulator size or available oil volume based on the gas law. The default adiabatic coefficient is 1.4 (nitrogen). For isothermal operation (slow cycling), use 1.0. Drag fields between the Variables and Results boxes to change what is calculated.
P₀ × V₀ⁿ = P₁ × V₁ⁿ = P₂ × V₂ⁿ
ΔV = V₀ × ((P₀/P₁)^(1/n) − (P₀/P₂)^(1/n))
The accumulator gas (nitrogen) follows the gas law where the pre-charge pressure P₀ and total volume V₀ determine the gas volume at different pressures. The usable volume ΔV is the difference in gas volumes at minimum and maximum pressure.
Example: A 10-liter accumulator with pre-charge 50 bar, minimum pressure 100 bar, maximum pressure 200 bar, n=1.4 → usable oil volume is approximately 2.9 liters.
Pre-charge pressure P₀
Set pre-charge to approximately 0.9 × minimum working pressure (bladder type) or 0.6 × minimum working pressure (piston type).
Isothermal (n = 1.0)
Used for slow processes where gas has time to reach ambient temperature (cycle time > 1 min).
Adiabatic (n = 1.4)
Used for fast processes where gas does not have time to dissipate heat (cycle time < 1 min).
Safety
An accumulator is a pressure vessel — follow manufacturer instructions and local regulations. Always use nitrogen, never oxygen.