A dry scroll pump is oil-free and clean, reaching around 10-2 mbar; an oil-sealed rotary vane pump reaches a deeper vacuum (down to ~2×10-3 mbar for a two-stage) at a lower purchase cost, but needs oil changes and carries a small risk of oil back-migration. Choose a scroll pump for clean, oil-free duty, and a rotary vane pump for the deepest vacuum at the lowest cost.
How each works
A scroll pump compresses gas between two interleaved spirals with no oil in the pumping chamber. A rotary vane pump uses sliding vanes in an oil-sealed chamber — the oil seals, lubricates and cools, which is how it reaches a deeper vacuum.
Oil-free vs oil-sealed
| Dry scroll | Rotary vane (oil-sealed) | |
|---|---|---|
| Oil in pumping chamber | None (oil-free) | Yes |
| Ultimate vacuum | ~10-2 mbar | ~10-1 (1-stage) to 2×10-3 mbar (2-stage) |
| Maintenance | Tip seals periodically; no oil | Regular oil changes; vanes/seals |
| Contamination risk | None | Small risk of oil back-migration |
Maintenance and running cost
Scroll pumps have no oil to change but do need periodic tip-seal replacement. Rotary vane pumps need regular oil changes and occasional vane/seal service. Over a pump’s life the running costs are comparable; the deciding factor is usually cleanliness, not cost.
Which should you choose?
Choose a scroll pump where oil contamination cannot be tolerated — clean labs, analytical work, or backing a turbo pump. Choose a rotary vane pump where you want the deepest vacuum at the lowest cost and can manage the oil. For the oil-free-versus-lubricated decision on a specific range, see our Sirella vs Evisa guide.
Scroll or rotary vane for your process?
Tell us whether oil-free operation matters and your target vacuum, and we’ll recommend the right pump. Email [email protected] or request a quote.
Frequently asked questions
Is a scroll pump better than a rotary vane pump?
Neither is universally better. Scroll pumps are oil-free and clean but reach about 10^-2 mbar; rotary vane pumps reach a deeper vacuum at lower cost but need oil. Choose by whether oil-free operation matters.
Which reaches a deeper vacuum, scroll or rotary vane?
A two-stage oil-sealed rotary vane pump reaches a deeper vacuum (around 2×10^-3 mbar) than a typical dry scroll pump (around 10^-2 mbar).
Which needs less maintenance, scroll or rotary vane?
Scroll pumps have no oil to change but need periodic tip-seal replacement; rotary vane pumps need regular oil changes plus vane and seal service. Overall effort is similar.
Written by the Girovac technical team. Girovac Ltd has supplied and serviced industrial and laboratory vacuum equipment from its North Walsham workshop since 1983. Last updated: July 2026.