Diffusion Pumps
Diffusion Pumps 3 products
High-vacuum diffusion pumps for vacuum coating, furnaces, metallurgy and research — high pumping speed at an economical price.
EquipLead time on quoteHigh Vacuum Oil Diffusion Pump
How to choose a diffusion pump
A diffusion pump boils a low-vapour-pressure fluid, sends the vapour up a chimney and out through angled nozzles as a supersonic jet aimed downwards. Gas molecules that wander into the jet are driven towards the exhaust and swept away by the backing pump. There are no moving parts, so the pump is quiet, cheap to own, tolerant of particles and effectively immortal if the fluid and cooling are looked after.
Read the full guide →FAQ
Is a diffusion pump still worth using?
For large-volume, high-throughput high vacuum where the process tolerates hydrocarbon or silicone oil, yes — it has no moving parts, is cheap for its pumping speed and is very tolerant of process upsets. Where backstreaming matters, a turbo pump has replaced it.
How do I stop oil backstreaming into the chamber?
Fit a water-cooled baffle or a liquid-nitrogen trap between pump and chamber, never open the high-vacuum valve before the pump is hot and stable, and do not run the pump above its maximum inlet pressure. Most backstreaming problems come from operating sequence, not from the pump.
How often does the pump fluid need changing?
When it darkens or the pump no longer reaches its rated pressure. Fluid life is destroyed by air inrush at operating temperature — a single accidental vent while hot can crack the oil and require a full change and cleaning of the jet assembly.