Strictly speaking, all gas/vapor motivated units are known as “ejectors”, while liquid motivated units are known as “eductors”. The terms are used interchangeably, however.
Our “AQUA-VACTOR” units use high pressure water as a motive and handle air as the suction gas. With motive water at a high enough pressure and a low enough temperature, a design suction pressure as low as 50 torr can be achieved discharging to atmospheric pressure. Aqua-vactors can also be staged with higher vacuum steam ejectors. In this case, the eductor serves both as the final pumping stage as well as a fairly good direct contact condenser, condensing the motive steam from the high vacuum steam ejectors.
This kind of eductor finds a wide use in priming centrifugal pump casings prior to startup. They also are frequently used for rough “house” vacuum in laboratories, and even in dentists offices. The jet venturi fume scrubber is also an example of this type of eductor.
Our “AQUA-DUCTOR” units use high pressure water as a motive to handle another liquid or slurry as the suction. They can easily handle particulate laden liquid streams that would destroy the internals of a standard pump.
In addition to boosting the pressure of the suction stream they provide excellent turbulent mixing between the motive and suction streams as well. For this reason, they are frequently used for mixing two components such as soda ash and water, forming a slurry of any required weight percent soda ash.
They an also be used to convey particulate matter (e.g. activated carbon particles). Eductor conveyors are frequently outfitted with a conical hopper on the suction, sometimes with wash down nozzles, to allow the particulates to efficiently flow into the suction connection by gravity.
They are also frequently used as sump or bilge pumps, especially shipboard.