What is the difference between an oil-free scroll pump and a rotary vane pump?

A rotary vane pump seals its working chamber with oil, so it reaches lower pressure but emits oil mist and needs regular oil changes. A scroll pump uses two interleaved spiral plates and tip seals to create trapped gas pockets, so the swept volume stays dry. It gives clean, hydrocarbon-free vacuum with no oil to change, at a slightly higher ultimate pressure and a higher purchase price.

How often do scroll pump tip seals need replacing?

Tip seals are the main wear item. In normal laboratory duty they last roughly 8,000 to 15,000 operating hours, typically two to four years. Abrasive particles and condensing solvent shorten that considerably, so an inlet trap is worth fitting. Replace the seals when the pump can no longer reach its rated ultimate pressure, and replace both scroll sets together.

Can a scroll pump run continuously?

Yes. Scroll pumps are designed for continuous duty and are commonly left running for days on concentrators, freeze dryers and coating systems. Keep the cooling air path clear, since these pumps are air-cooled, and avoid restricting the exhaust.

Does JWRESEARCH supply oil-free scroll vacuum pumps in Singapore?

Yes. JWRESEARCH supplies oil-free scroll vacuum pumps from small single-scroll benchtop units to larger dual-scroll models, with inlet traps, exhaust silencers, hose and KF fittings, tip seal service kits, and delivery across Singapore.

Oil-Free Scroll Vacuum Pumps Singapore

Published: {{NEW_ARTICLE_DATE}} | By JWRESEARCH | Category: Laboratory Equipment

A rotary vane pump is cheap, robust and everywhere — and it puts oil into everything it touches. Mist on the bench, oil in the trap, a sump that must be drained and refilled, and a real risk of backstreaming into a clean chamber when the pump stops.

An oil-free scroll pump removes that entire category of problem. JW RESEARCH SUPPLY supplies dry scroll pumps and service parts to laboratories across Singapore; this guide explains how the technology works, where it fits, and what it costs to own.

How a Scroll Pump Produces Vacuum

Two identical spiral plates face each other, one fixed and one orbiting on a crank with a small eccentric throw. As the moving scroll orbits, crescent-shaped pockets of gas are trapped between the plates, squeezed progressively toward the centre and expelled through the discharge port.

Because the plates never touch, the gas path is dry. Tip seals — thin polymer strips in a groove along the spiral edge — do the sealing, and they are the only part that wears. There is no oil, no filter element and no oil mist to exhaust.

The motion is smooth and counterbalanced, so vibration is low and the pump can sit on a bench next to a balance without walking across it.

Specification Reference

Parameter	Typical Range	What It Determines
Pumping speed	1.5 – 50 m³/h	Evacuation time and gas load capacity
Ultimate pressure	1 – 10 Pa (0.01 – 0.1 mbar)	Whether the application needs fine vacuum
Stages	Single or dual scroll	Lower ultimate pressure with two stages
Motor power	0.2 – 1.5 kW	Heat load and electrical supply
Noise level	50 – 62 dB(A)	Suitability for an occupied laboratory
Inlet connection	KF16, KF25, KF40	Hose and trap compatibility
Tip seal life	8,000 – 15,000 h	Maintenance interval and cost
Cooling	Air-cooled, fan-assisted	Clearance needed around the housing
Operating temperature	5 – 40 °C ambient	Performance in a hot plant room

Scroll Versus Vane Versus Diaphragm

Attribute	Oil-free scroll	Rotary vane	Diaphragm
Ultimate pressure	0.01 – 0.1 mbar	0.001 – 0.01 mbar	1 – 10 mbar
Oil in the gas path	None	Yes	None
Continuous duty	Yes	Yes, with oil management	Yes
Main wear item	Tip seals	Vanels, oil, filters	Diaphragms, valves
Typical use	Rotovaps, freeze dryers, concentrators	General rough vacuum, Schlenk lines	Filtration, aspiration, degassing

Where a Scroll Pump Earns Its Price

The applications share one requirement: nothing from the pump may reach the sample. Rotary evaporation is the classic case, since solvent vapour and oil mist meet in the same exhaust line and a vane pump will happily return both to the flask.

Freeze drying, centrifugal concentrators, gel dryers, vacuum ovens and coating or sputtering systems all benefit. In semiconductor and surface-science work the absence of hydrocarbons is not a preference but a specification.

It is also the quieter choice. At around 55 dB(A) a scroll pump can run in the same room as the operator, which a vane pump at 65 dB(A) usually cannot.

Sizing and Installation

Size on gas load, not on chamber volume alone. A dry 5 L flask pulls down quickly with any pump; a flask of boiling solvent releases litres of vapour per minute and needs real pumping speed. As a rule, allow 20 to 30 per cent headroom over the calculated load so the pump is not running at its limit all day.

Fit an inlet trap — a cold trap or a coalescing and activated-carbon cartridge — wherever condensable vapour is present. The trap protects the tip seals, and replacing a cartridge is far cheaper than rebuilding a scroll set.

Keep the cooling air path clear, leave 100 mm around the housing, and do not throttle the exhaust. Use KF-barbed hose kept as short and wide as practical; a long 8 mm hose can cost more pumping speed than the pump choice itself.

Maintenance and Cost of Ownership

There is no oil to change, which is the headline saving, but the pump is not maintenance-free. Tip seals wear, and the tell-tale is a slow drift upward in ultimate pressure. When the pump no longer reaches its rated vacuum, fit a service kit.

Bearing grease is sealed for life on most benchtop models. Beyond tip seals, the practical costs are inlet traps, exhaust silencers and the occasional fan filter cleaning — a fraction of the oil, filter and disposal costs of a vane pump over five years, though the purchase price is roughly double.

Frequently Asked Questions

Can a scroll pump be used with corrosive vapours?
Only with care. Acid and halogen vapours attack the aluminium scrolls, so use a cold trap and, for routine corrosive duty, choose a chemically resistant model with coated plates.

Why is the ultimate pressure worse than a vane pump?
The tip seal is a sliding contact, not a liquid film, so a small leak past it is unavoidable. Single-stage scrolls stop around 0.1 mbar and dual-stage around 0.01 mbar, which covers most laboratory work.

Can I repair the pump myself?
Tip seal replacement is a straightforward procedure with the right kit and a clean bench, and it is worth doing in-house if you run several pumps. Scroll plate damage needs factory service.

Does JWRESEARCH supply scroll pumps in Singapore?
Yes — single and dual-scroll oil-free pumps, inlet traps, exhaust silencers, KF fittings, hose and tip seal service kits, with delivery across Singapore.

Contact JWRESEARCH

JW RESEARCH SUPPLY — laboratory equipment and consumables, Singapore.
Tel / WhatsApp: +65 8039 3660
Email: SINGAPORE@JWSHY.COM
Website: www.jwresearch.cn