Vacuum Pump Types: Which One Fits Handling and Lab?
Rotary vane, diaphragm or Venturi ejector - each vacuum pump type has its own strengths in ultimate pressure and pumping speed. This guide explains the operating principles, the key figures and how to pick the right pump for handling, assembly and the lab.
Browse vacuum technologyHow do the operating principles differ?
Vacuum pumps create low pressure by moving gas out of an enclosed volume. Rotary vane, diaphragm and Venturi pumps do this in very different ways, which drives ultimate pressure, pumping speed and maintenance needs.
The rotary vane pump uses an eccentrically mounted rotor with sliding vanes that compress the gas in cells. Oil seals the gap and lubricates, so very low ultimate pressures down to around 0.1 mbar are possible.
The diaphragm pump flexes an elastic membrane up and down, controlled by check valves. It runs oil-free and dry but only reaches an ultimate pressure of about 70 to 100 mbar. The Venturi ejector has no moving parts: compressed air flows through a nozzle and, by the Venturi effect, entrains air to create the vacuum.
Pumping speed and ultimate pressure - what really counts?
Two figures decide suitability: pumping speed in m³/h (how fast the pump evacuates) and ultimate pressure in mbar (how deep the achievable vacuum is). Handling needs fast pumping speed above all; lab and process work needs a low ultimate pressure.
- Pumping speed: sets the evacuation time of a volume - a larger chamber needs more m³/h.
- Ultimate pressure: limits the deepest achievable vacuum, crucial for distillation or freeze drying.
- Leak rate: leaking fittings spoil any ultimate pressure - check tightness before choosing a pump.
- Holding force when gripping: vacuum level and cup area determine the force on the workpiece.
Which pump for handling, assembly or lab?
The choice follows the application. If you grip workpieces, the Venturi ejector is the most economical; if the lab needs deep, clean vacuum, pick diaphragm or rotary vane depending on the target ultimate pressure.
- Handling and assembly: Venturi ejector straight off the compressed air, fast cycling, no moving parts to service.
- Oil-free lab: diaphragm pump for filtration, rotary evaporators at medium vacuum and aggressive media.
- Fine vacuum and processes: oil-sealed rotary vane pump for ultimate pressures below 1 mbar.
- Central supply: larger rotary vane ranges up to 630 m³/h serving several workstations.
Frequently asked questions
Which vacuum pump type reaches the lowest ultimate pressure?
Oil-sealed rotary vane pumps reach the deepest ultimate pressure at 0.1 to 2 mbar. Diaphragm pumps stay around 70 to 100 mbar, and Venturi ejectors are typically near 130 mbar.
When does a Venturi ejector make sense?
Whenever a compressed air network is available and gripping runs in fast cycles. The ejector has no moving parts, needs little maintenance and is ready to work instantly.
Oil-free or oil-sealed?
Oil-free diaphragm and ejector pumps keep processes clean and suit aggressive vapours. Oil-sealed rotary vane pumps reach far lower ultimate pressures but need oil changes and oil mist separation.
How do I calculate the required pumping speed?
From the volume to be evacuated and the target evacuation time. Larger chambers and short cycle times demand more m³/h; always allow for the system leak rate.
Looking for the right vacuum pump?
Whether a Venturi ejector for handling or a rotary vane pump for the lab - we supply the right vacuum technology with advice on pumping speed and ultimate pressure.
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