Rotary Vane Vacuum Pumps Singapore
A rotary vane pump is the workhorse of the laboratory vacuum system: it pulls filtration flasks, rotary evaporators, vacuum ovens, freeze dryers and distillation trains, often for hours at a time on solvent-laden vapour. It is also the equipment most often damaged by its own duty, because what gets discussed is the headline ultimate vacuum rather than pumping speed at the pressure where the work happens.
At JW RESEARCH SUPPLY, we supply single-stage and two-stage rotary vane pumps, traps, filters, oil and service parts to chemistry, pharmaceutical, food, environmental and teaching laboratories across Singapore. This guide covers how the pump works, how to read a vacuum curve, and what protects it in daily use.
How a Rotary Vane Pump Works
An offset rotor carries sliding vanes inside a stator. As the rotor turns, the space between adjacent vanes grows on the inlet side, drawing gas in, and shrinks on the outlet side, pushing it past the exhaust valve. Oil seals the clearances, lubricates the vanes and fills the dead volume under the exhaust valve — which is why solvents and water in the gas stream matter so much.
Two stages in series, with the exhaust of the first feeding the inlet of the second, extend the working range down to the 0.001 to 0.01 mbar region. A single stage stops at roughly 0.5 to 5 mbar, which covers more laboratory duties than most buyers expect.
| Pump Class | Ultimate Vacuum | Typical Speed | Common Duty |
|---|---|---|---|
| Single-stage, small | 5 – 10 mbar | 1 – 2 m³/h | Single filtration manifold, small rotary evaporator |
| Single-stage, standard | 0.5 – 5 mbar | 2 – 6 m³/h | Vacuum distillation, vacuum ovens, gel dryers |
| Two-stage, standard | 0.005 – 0.05 mbar | 2 – 8 m³/h | Short-path distillation, Schlenk lines, freeze drying |
| Two-stage, high capacity | 0.001 – 0.01 mbar | 8 – 20 m³/h | Pilot freeze dryers, concentrators, multi-port manifolds |
Specification Reference
| Parameter | Typical Value | What It Affects |
|---|---|---|
| Stages | 1 or 2 | Lowest achievable pressure |
| Pumping speed | 1 – 20 m³/h at 50 Hz | Time to working pressure and gas load handling |
| Ultimate total pressure | 0.001 – 10 mbar, gas ballast closed | Whether the duty pressure is reachable |
| Pressure with gas ballast open | 0.5 – 20 mbar | Water and solvent vapour tolerance while drying |
| Motor | 0.25 – 1.5 kW, 220 – 240 V / 50 Hz | Singapore mains compatibility and heat load |
| Oil capacity | 0.3 – 2.0 L | Service interval and contamination tolerance |
| Inlet / outlet | KF16, KF25, KF40 | Tubing, trap and filter compatibility |
| Noise level | 50 – 62 dB(A) | Placement inside a shared laboratory |
| Oil type | Mineral or synthetic, ISO VG 32 – 68 | Chemical resistance and vapour pressure |
Sizing the Pump
Size from the gas load at the working pressure, not from chamber volume alone. A pump that reaches 0.01 mbar on a clean dry system may sit at 3 mbar under solvent load, because vapour keeps boiling off. Read the speed curve at your duty pressure; a pump quoted at 6 m³/h at atmospheric pressure may deliver under 1 m³/h at 1 mbar. Narrow tubing, long runs, a cold trap and an oil mist filter all reduce effective speed at the chamber.
Protecting the Pump
Cold traps. A trap between chamber and pump condenses solvent and water before they reach the oil. Use dry ice and acetone for most organic solvents and liquid nitrogen where very volatile material or water vapour must be stopped. Empty the trap before it fills and never let it warm while the pump is pulling.
Gas ballast. Opening the gas ballast admits air to the compression stroke so condensable vapour is swept out before it liquefies in the oil. Use it during evaporation and drying, accept the higher base pressure, and close it only when you need ultimate vacuum.
Filters and non-return valves. An exhaust filter keeps oil mist out of the room, and an inlet non-return valve stops oil being sucked back into the chamber when the pump stops. Both are cheap compared with a contaminated batch.
Oil and Maintenance
Check the oil level weekly and the colour monthly. Fresh oil is clear; oil that has turned dark, milky or gritty has taken on solvent, water or particulates and should be changed with the oil filter where fitted. Use only the grade specified — mixing mineral and synthetic oils or topping up with the wrong viscosity changes the base pressure and can attack the vanes. Replace vanes and gaskets at the recommended interval, keep a service kit on the shelf, and after any wet duty run the pump briefly with the inlet blanked before storage.
Selection Checklist
- State the working pressure you need, not the lowest pressure advertised.
- Read pumping speed at that pressure, then allow for trap, filter and tubing losses.
- Choose two stages only when the duty goes below about 1 mbar.
- Add a cold trap, oil mist filter and inlet non-return valve to every solvent duty.
- Confirm 220 – 240 V / 50 Hz and stock oil plus a service kit with the pump.
Frequently Asked Questions
Can one pump serve several stations?
Yes, with a manifold and isolation valves, but size for the combined gas load and accept that one leak affects every station. Dedicated small pumps per evaporator are usually better.
How often should the oil be changed?
Every 500 to 1000 operating hours, or sooner on heavy solvent duty. Change it when it darkens or the base pressure drifts, not only on the calendar.
Is a diaphragm pump a better choice?
It is oil-free but usually reaches only 1 to 10 mbar and costs more per unit of speed; use it where oil contamination is unacceptable.
Does JWRESEARCH supply rotary vane pumps in Singapore?
Yes — single and two-stage pumps, traps, filters, gauges, tubing, oil and service kits, delivered across Singapore.
Contact JWRESEARCH
JW RESEARCH SUPPLY — laboratory equipment and consumables, Singapore.
Telephone / WhatsApp: +65 8039 3660
Email: SINGAPORE@JWSHY.COM
Website: www.jwresearch.cn