Vacuum Pump Capacity Calculation Xls 🎁 Fully Tested

| Load Type | Formula | Calculated Value | Unit | |-----------|---------|------------------|------| | Leak load | =Q_leak | 0.05 | mbar·L/s | | Outgassing load | =q_outgas * A_surface | 0.005 | mbar·L/s | | Process gas load | =Q_process | 0.02 | mbar·L/s | | Total gas load (Q_total) | =SUM(above) | 0.075 | mbar·L/s |

[ S_required = \fracQ_totalP_base ]

Where:

| Parameter | Unit | Typical Range | Example | | :--- | :--- | :--- | :--- | | Chamber Volume | Liters / m³ | 0.1 – 100,000 | 1,000 L | | Start Pressure | mbar (abs) | 1013 | 1013 | | Target Pressure | mbar (abs) | 0.001 – 100 | 0.01 | | Allowed Evacuation Time | Minutes | 1 – 60 | 10 min | | Total Leak Rate | mbar·L/s | 0.001 – 1.0 | 0.05 | | Outgassing Rate | mbar·L/s·cm² | 1e-6 – 1e-3 | 1e-5 | | Internal Surface Area | cm² | Calculated or input | 50,000 | vacuum pump capacity calculation xls

Alex recalled the fundamental vacuum equation:

Seff = (V / t) × ln(P_start / P_target) + (Q_total / P_target)

Where:

Formula:
[ S_req = \fracVt \times \ln\left(\fracP_startP_target\right) ]

| Parameter | Value | |-----------|-------| | ln(P_start / P_target) | =LN(B4/B5) → ~11.53 | | S_req (L/s) | = (V * ln_ratio) / (t_desired*60) | | Example result | (50011.53)/(1060) = 9.61 L/s |

Alex knew pumps have different speeds at different pressures. So they added: | Load Type | Formula | Calculated Value

This calculates the capacity needed to maintain a vacuum while the process generates gas/leaks.

| Cell | Label | Value / Formula | |------|-------|------------------| | B3 | Chamber Volume (liters) | User input | | B4 | Initial Pressure (mbar abs) | 1013 | | B5 | Final Pressure (mbar abs) | User input | | B6 | Desired Evacuation Time (s) | User input | | B7 | Pipe Conductance (L/s) – if known | User input | | B8 | Outgassing + Leak Correction Factor (default 1.15) | User input |