Vacuum Pump Oil and Fluids Singapore
Pump oil is the cheapest component in a vacuum system and the one most often ignored. It is specified once, at commissioning, and then topped up from whatever bottle is on the shelf. Yet the fluid is the actual seal in a rotary vane pump: it fills the clearance between vane and cylinder, carries heat away, and traps the gas being displaced. Wrong oil, old oil or water-contaminated oil shows up as a base pressure that creeps upward, a pump that runs hot, and eventually a seized rotor.
At JW RESEARCH SUPPLY, we supply mineral, synthetic hydrocarbon, silicone and PFPE vacuum fluids, oil-mist filters and pump service kits to laboratories across Singapore. This guide covers the four fluid families, the numbers that matter when comparing them, and a change routine that suits a humid tropical site.
The Four Fluid Families
Selection starts with what the pump has to swallow. A clean chemistry pump backing a turbomolecular pump has different demands from one handling dichloromethane on a rotary evaporator five days a week.
| Fluid Family | Vapour Pressure at 25 °C | Chemical Resistance | Typical Use |
|---|---|---|---|
| Mineral oil (hydrocarbon) | 10⁻⁴ – 10⁻⁵ mbar | Poor to solvents and acids | Clean, dry duty: filtration, drying, general roughing |
| Synthetic hydrocarbon (PAO) | 10⁻⁵ – 10⁻⁶ mbar | Moderate | Longer service life, higher temperature, cleaner vacuum |
| Silicone oil | 10⁻⁶ – 10⁻⁷ mbar | Good to water and many solvents | Freeze drying, humid samples, moderate chemical load |
| PFPE (perfluoropolyether) | 10⁻⁷ – 10⁻⁸ mbar | Excellent: acids, oxidisers, most solvents | Corrosive vapour, oxygen service, semiconductor and UHV backing |
Specification Reference
| Parameter | Typical Value | What It Affects |
|---|---|---|
| ISO viscosity grade | VG 32, 46, 68, 100 | Sealing at operating temperature, starting torque in cold rooms |
| Vapour pressure at 25 °C | 10⁻⁴ – 10⁻⁸ mbar | The lowest pressure the pump can reach |
| Pour point | −10 °C (mineral) to −40 °C (synthetic, PFPE) | Cold-room and freezer-adjacent installations |
| Flash point | 200 – 270 °C | Safety where solvent vapour is present |
| Density at 20 °C | 0.85 – 1.90 g/cm³ | Whether a sight glass marked in litres reads correctly |
| Water solubility | Low (mineral), very low (PFPE) | Emulsification risk in humid conditions |
| Pack size | 1 L, 4 L, 20 L, 200 L | Cost per litre against shelf life of an opened pack |
| Service life (clean duty) | 500 – 1000 h (mineral), 2000 h+ (PFPE) | Consumption planning and maintenance schedule |
Viscosity and Vapour Pressure: The Two Numbers That Decide
Viscosity is chosen at operating temperature, not at the shelf. A VG 46 oil that seals well at 60 °C in a running pump may be too stiff to start at 15 °C in an air-conditioned plant room, and too thin once the pump has been running for an hour. Follow the pump manufacturer's grade; going thicker to "improve sealing" usually increases running temperature and shortens oil life.
Vapour pressure sets the floor of the achievable vacuum. If the oil has a vapour pressure of 10⁻⁴ mbar, no amount of pumping will take the chamber below that, because the oil itself is evaporating into it. This is why PFPE fluids are specified where a clean high vacuum is required, and why a mineral oil charge in a system that must reach 10⁻⁵ mbar is a design error rather than a maintenance problem.
Change Intervals in a Tropical Laboratory
A clean, dry duty with a gas ballast in daily use can run 500 to 1000 hours between changes. Solvent vapour, biological samples, freeze dryers and air-conditioned rooms at 80% relative humidity all shorten that sharply; 200 to 300 hours is realistic for a rotary evaporator pump in heavy use.
Judge by condition as well as hours. Drain a few millilitres into a clear glass: amber and clear is normal, milky means water, black or gritty means oxidation and wear. A pump that no longer reaches its usual base pressure after an oil change has a worn vane, a blocked exhaust filter or an inlet leak — not an oil problem.
Always change the oil warm, drain fully, and replace the oil-mist filter at the same time. A saturated exhaust filter pushes oil vapour back into the room and raises crankcase pressure; in a small laboratory that is both a smell and a slipping hazard.
Handling, Storage and Disposal
Store packs sealed, upright and away from sunlight; an opened 20 L drum absorbs moisture over months. Label every top-up container with the fluid type and date, and never decant PFPE into an unmarked bottle — cross-contamination destroys an expensive charge in minutes. Used oil is scheduled waste in Singapore: collect it in a labelled container, do not mix it with solvent waste, and dispose through a licensed contractor.
Frequently Asked Questions
Can I top up with a different brand of the same grade?
Within the same family and viscosity grade it is usually acceptable in an emergency. Drain and refill at the next service rather than running a mixed charge indefinitely.
Does gas ballast waste oil?
It shortens oil life slightly by letting more vapour pass through, but it prevents water and solvent from condensing in the oil in the first place. Use it during wet runs and close it once the pump has purged.
Is PFPE oil worth the cost?
For acid, oxidiser or oxygen service, yes — it is the difference between a pump lasting years and being rebuilt annually. For clean filtration duty, a synthetic hydrocarbon gives most of the benefit at a fraction of the price.
Does JWRESEARCH supply vacuum pump oil in Singapore?
Yes — mineral, synthetic hydrocarbon, silicone and PFPE fluids in 1 L, 4 L and 20 L packs, plus oil-mist filters, exhaust filters and drain kits, delivered 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