Rotary Vane Vacuum Pumps: Oil-Sealed and Dry Running Models

How a Rotary Vane Vacuum Pump Works

This type of vacuum pump is built around a slotted rotor that sits off centre in a round housing. As the rotor turns:

1. The vanes slide out and press against the housing wall.
2. Gas enters the growing space between two vanes at the inlet.
3. The space shrinks as the rotor turns, compressing the gas.
4. The gas is pushed out through an exhaust valve.

It is the same basic idea as a hydraulic vane pump, working on gas instead of oil.

Oil Sealed or Dry Running?

Oil Sealed Pumps

Oil seals the gaps between the vanes and the housing, and it also cools the pump and carries away heat. That is how these pumps reach a deep rough vacuum: often around 0.1 mbar for single stage models, and lower for two stage designs. An exhaust filter catches the oil mist before it leaves the pump.

Dry Running Pumps

Carbon vanes run without oil, so the exhaust air stays clean. These pumps usually stop at a shallower vacuum, often around 100 to 150 mbar, which suits hold down, conveying and simple packing. The vanes wear slowly and need regular checks.

What the Oil Is Telling You

• Clear amber: the oil is healthy, so carry on.
• Milky or cloudy: water vapour has condensed in the oil. Run the gas ballast and change the oil.
• Dark, or a burnt smell: the pump is running too hot, or the oil change is overdue.
• Level drops quickly: the exhaust filter may be letting oil through.

Use the oil the maker specifies. Vacuum pump oil has a low vapour pressure, so general-purpose oils will not reach the same vacuum.

Service Points

1. Change the oil and oil filter at the hours the maker sets, or sooner on dusty or wet duties.
2. Replace the exhaust filter when oil mist appears at the outlet.
3. Clean or replace the inlet filter, so dust does not scratch the vanes.
4. On dry pumps, measure the vane length and replace the vanes before they reach the wear limit.
5. Before pumping wet gas, let the pump warm up with the inlet closed.

Rotary Vane Vacuum Pumps Specifications to Check

• Ultimate vacuum and pumping speed
• Oil sealed or dry running design
• Gas type, moisture and any vapour
• Motor power, voltage and phase
• Inlet and outlet connections

Where They Work

Rotary vane vacuum pumps are a favourite in food packaging, CNC router hold down, plastics thermoforming, vacuum lifting and lab work. If your gas carries a lot of water, a liquid ring pump will cope far better. If you need oil-free running with longer service intervals, check our claw vacuum pumps.

Why Buy From TSA Hydraulics Engineering

As a rotary vane vacuum pumps supplier, we match the pump model, oil type and service kit, not just the vacuum figure. You get OEM or equivalent options, and help sourcing rotary vane vacuum pumps replacement parts such as vanes, exhaust filters, inlet filters and oil. We tell you upfront whether a pump or part is genuine or an equivalent.