The vacuum ejector, or pneumatic vacuum generator, is a small, economic vacuum component that uses a positive pressure air source to generate negative pressure (vacuum).
Working principle of vacuum ejector
The vacuum ejector produces vacuum by means of Venturi effect. The ejector uses a Venturi nozzle to spray compressed air at high speed and form a jet at the nozzle outlet, thus producing a volume suction flow.
Under the effect of such suction, the air around the nozzle outlet is continuously pumped. Thus, the pressure in the chamber drops below atmospheric pressure to generate vacuum.
Advantages of vacuum ejector
- Compact design and light weight
- Almost no maintenance required
- Small flow rate
- Compressed air system is required
Only low vacuum can be generated. (Reference: 1st stage: 810mm HgA – 30mm HgA, 2nd stage: 130mm HgA – 3mm HgA)
- Continuous operation not allowed
Therefore, such vacuum ejectors are used in pick and place applications and low cost food packaging machines, etc.
The vacuum pump however, can be defined as an electric vacuum generator. One of the popular types is rotary vane vacuum pump that achieves much higher vacuum during eccentric movement of rotary vanes inside the vacuum chamber.
With advantages that vacuum ejectors don’t have, the vacuum pumps have various industrial applications with much less limitations such as vacuum furnace, vacuum coating, etc.