If your plant is located significantly above sea level, atmospheric pressure ( P1cap P sub 1
where: S = required pump capacity (L/s or m³/h) V = system volume (L or m³) P = desired vacuum level (units of pressure) t = pumping time (seconds or hours) Q = gas load (L/s or m³/h)
Create a second sheet, Evac_Curve , to solve for time to reach each pressure: vacuum pump capacity calculation xls
However, the exact outgassing rate depends on:
Place these in an isolated reference tab to feed your formulas seamlessly. Excel Cell Example Atmospheric Pressure B2 Standard Safety Factor B3 Conversion: Multiplier B4 Section B: User Inputs (Data Entry) If your plant is located significantly above sea
) is lower. Update the initial pressure constant in your XLS to reflect your specific altitude to ensure accurate pull-down curves. For deep vacuum systems (
Add equivalent flow ( Q/p ) to the required pump speed. For deep vacuum systems ( Add equivalent flow
$$ S = \fracVt \cdot \ln\left(\fracp_1p_2\right) $$
System leaks and gas evolution from materials (outgassing) must be included to ensure the pump can maintain the vacuum. 3. Core Formulas for Vacuum Calculation