Here’s the exact table you can paste into cells A1 downwards:
Alex decided to build a in Excel.
| Parameter | Symbol | Value | Unit | |-----------|--------|-------|------| | Chamber volume | V | 500 | Liters | | Starting pressure (atmospheric) | P_start | 1013 | mbar | | Target pressure (vacuum level) | P_target | 0.01 | mbar | | Desired pump-down time | t_desired | 10 | minutes | | System leak rate (estimated) | Q_leak | 0.05 | mbar·L/s | | Outgassing rate (per surface area) | q_outgas | 1.0E-06 | mbar·L/(s·cm²) | | Internal surface area | A_surface | 5000 | cm² | | Process gas load (e.g., water vapor) | Q_process | 0.02 | mbar·L/s | | Conductance between pump & chamber | C | 100 | L/s | vacuum pump capacity calculation xls
For ready-made templates, you can refer to these specialized tools:
For outgassing, many professional tools (including some advanced XLS calculators) take a two-pronged approach: a simple added to the calculated pump speed to account for minor, unknown loads. Here’s the exact table you can paste into
| Parameter | Symbol | Value | Unit | |-----------|--------|-------|------| | Vessel volume | V | 2.5 | m³ | | Desired pressure (absolute) | P_target | 10 | mbar | | Initial pressure (atm) | P_start | 1013 | mbar | | Allowed pump-down time | t | 10 | minutes | | Leakage rate (measured) | Q_leak | 0.5 | mbar·L/s | | Outgassing rate (from material tables) | Q_outgas | 1.2 | mbar·L/s |
INPUT PARAMETERS: Chamber Volume (liters) 6000 Initial Pressure (mbar abs) 1013 Final Pressure (mbar abs) 5 Desired Pump-Down Time (s) 180 Pipe Conductance (L/s) 1200 Correction Factor (outgassing/leak) 1.15 vacuum pump capacity calculation xls
A1: VACUUM PUMP CAPACITY CALCULATOR A3: SECTION 1 – INPUT DATA A5: Parameter B5: Value C5: Unit A6: Vessel volume (m³) B6: 2.5 C6: m³ A7: Desired pressure (abs) (mbar) B7: 10 C7: mbar A8: Atmospheric pressure (mbar) B8: 1013 C8: mbar A9: Pump-down time (minutes) B9: 10 C9: min A10: Leakage rate (mbar·L/s) B10: 0.5 C10: mbar·L/s A11: Outgassing rate (mbar·L/s) B11: 1.2 C11: mbar·L/s