For a rotary vane pump: 70 / 0.95 = 73.7 m³/h → choose 80 m³/h model.
when running close to its ultimate blank-off pressure. Always consult the manufacturer's performance curve and multiply your calculated capacity by the efficiency factor at your specific target pressure. 5. Summary Checklist for Verification
"Now," Elias said, his voice dropping an octave. "Here is where most young engineers fail. They buy a pump for the air load, turn it on, and the pump overheats and shuts down in ten minutes. Why?"
At low pressures, gas molecules collide with pipe walls rather than each other (molecular flow), severely dropping effective pumping speed. vacuum pump capacity calculation xls
I cannot directly provide or attach an .xls file, but I can give you a that you can directly implement into Excel to build your own Vacuum Pump Capacity Calculator .
Once at vacuum, the pump must handle continuous gas loads from leaks ( QLcap Q sub cap L ) and process outgassing or vapors ( QPcap Q sub cap P
): Vapors can be converted to throughput using the ideal gas law: Recommended XLS Template Structure For a rotary vane pump: 70 / 0
Vacuum pump capacity is expressed as Volumetric Flow Rate or Pumping Speed (
Lucas reopened the spreadsheet. He deleted the steady-state assumption and replaced it with the pump-down formula for a rough vacuum: $$t = \fracVS \times \ln\left(\fracP_1P_2\right)$$ Where:
To help tailor this template, what specific (e.g., chemical distillation, HVAC evacuation, manufacturing) are you sizing this pump for? Share public link They buy a pump for the air load,
: These require more complex calculations involving duct cross-sectional areas and flow velocities. For instance, Automation Components, Inc. suggests calculating flow volume (CFM) by multiplying velocity (FPM) by the duct area. Key Considerations for Sizing
| Condenser Type | Outgassing Load Calculation | | :--- | :--- | | | The cooling water will release dissolved air as it is heated and enters the vacuum. This can be a large and variable load | | Surface (Shell & Tube) | The process vapor is cooled via a metal wall. The outgassing load on the vacuum pump is significantly lower as there is no direct contact with cooling water |