Trimix Fill Station

Transparent partial-pressure blending, source-gas corrections, and calculation audits. Designed for independent verification.

01 · Cylinder contents

Analyze before calculating

Starting pressure PSI

O₂ %

He %

Enter the actual starting pressure and analyzed gas mix. No cylinder size or rated-pressure input is needed for a pressure-based calculation.

02 · Target blend

Operator-selected settled pressure

Final pressure PSI

O₂ %

He %

03 · Gas sources

He → O₂ → top-off

Top-off O₂ %

Top-off He %

Helium source purity %

O₂ source purity %

For sub-100% source purity, the remaining fraction is modeled as nitrogen. Does not model argon or other trace gases.

Calculate minimum bleed-down if necessary
Retain as much of the starting gas as possible if the target is otherwise unattainable.

Pressure accounting

Gauge basis matches conventional hand calculations. Absolute basis includes the residual gas at ambient pressure, assuming the entered starting mix is correct.

Verification before filling

LIMITATIONS

This release uses ideal-gas pressure addition at a single, uniform temperature. It does not correct for real-gas compressibility, fill heating/cooling, pressure-gauge error, source bank limitations, or regulator/boosting losses. High-pressure helium blends can differ materially from the predicted composition.

Use this build only to compare calculations. Do not use it as the sole basis for live filling. Qualified blending procedures, appropriate oxygen-compatible equipment and air, cylinder limits, and independent O₂/He analysis remain essential.

Top-off simulator

Predict final mix

Existing PSI

Starting O₂ %

Starting He %

Top to PSI

Bank O₂ %

Bank He %

What-if mixes the cylinder contents with a selected bank gas without adding pure He or O₂ separately. Composition estimates use the same ideal-gas basis selected in the blend planner.

Depth and gas analysis

OC / CCR

O₂ %

He %

Depth FT

OC MOD limit · PPO₂

CCR loop setpoint

Gas density uses 0°C reference densities. CCR loop model assumes maintained setpoint and inert gas proportions derived from diluent. It is not a dynamic loop simulation.

END estimates are provided with O₂ + N₂ narcotic and N₂-only assumptions. Density thresholds are 5.2 g/L preferred and 6.3 g/L upper guideline per BSAC; they are not stand-alone gas-selection criteria.

Temperature pressure correction

Ideal gas / fixed amount

Observed PSI

Measured temp °F

Reference temp °F

Uses absolute pressure and Kelvin. Cylinder and gas must reach uniform temperature for a reliable settled reading.

Temperature compensation here is ideal-gas only. It does not turn the blending engine into a real-gas model, and does not model the transient temperature during He or oxygen addition.