Preliminary Vacuum-System Estimator

Pumping speed interpolated between the six manufacturer-published points. Target-pressure estimates run from 280 to 950 mbar, using manufacturer-published pumping-speed data covering 280–1000 mbar.

Linear interpolation of six manufacturer-published points Published data points Pressure interval used for the time estimate Below 280 mbar — no manufacturer speed data (chart starts at 250 mbar) Target pressure Ultimate vacuum 13 mbar is a manufacturer rating, not a speed — it is off this chart
Estimated speed at target
8.8 L/min
Idealized time from 1000 mbar
8 s
Ultimate vacuum
13 mbar

Preliminary teaching tool, not sizing software. Speeds between the published points are linearly interpolated; below 280 mbar the manufacturer publishes no speed data, so no values are estimated there. Times integrate the throughput balance for a closed, leak-tight, isothermal system using the linearly interpolated manufacturer-published speed data, t = V ∫ dp / [S(p) · p], starting from the 1000 mbar end of the published table rather than from standard atmospheric pressure. Real systems are slower: hose and trap conductance, leaks, outgassing and above all evaporating solvent vapor add load. Confirm pump selection against your own process and the manufacturer’s documentation.