Formula: [ \frac1S_eff = \frac1S_pump + \frac1C ]
Selecting the wrong vacuum pump is expensive. An undersized pump leads to excruciatingly long evacuation times, production bottlenecks, and even system failure due to overheating. An oversized pump wastes capital, consumes excessive energy, and can pull unwanted vapors or particles through the system. vacuum pump capacity calculation xls
| 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 | Formula: [ \frac1S_eff = \frac1S_pump + \frac1C ]
| Chosen S_pump | S_eff | t_actual (seconds) | t_actual (minutes) | |---------------|-------|--------------------|--------------------| | 12 L/s | 10.71 | =500/10.71*LN((1013-0.075/10.71)/(0.01-0.075/10.71)) → ~530 s | ~8.8 min | | Cell | Label | Value / Formula
"Good," Elias nodded. "Now, for a vessel this size, operating at low vacuum, we can estimate the leakage based on the internal volume. In cell B6, type 'Leakage Factor'. Since our joints are old and rusty, use a conservative factor. Let's say 0.2 kg/hr per m3."
Stotal=Sevacuation+QL+QOPtargetcap S sub t o t a l end-sub equals cap S sub e v a c u a t i o n end-sub plus the fraction with numerator cap Q sub cap L plus cap Q sub cap O and denominator cap P sub t a r g e t end-sub end-fraction Setting Up Your Excel Sheet (XLS)
Need help building a custom XLS for a specific industrial application? Consult a vacuum process engineer or share your requirements in the comments below.
