Apart from single-stage water jet-, gas jet- and steam jet vacuum ejectors the most frequent apparatus used to generate a vacuum is a multi-stage steam jet vacuum system. Water vapour is generally used as a motive agent, but in special cases process vapours may be used too. In these systems the motive- and suction vapours are condensed in mixing- or surface condensers, at preferably low pressures to keep the energy input for further compression activities as low as possible. When using multi-stage steam jet vacuum systems it is possible to achieve absolute suction pressures down to 0.01 mbar.

In hybrid systems you will find ejectors combined with liquid ring vacuum pumps so that the advantages of both pump types are integrated in one system.

Ice/dry condensation vacuum systems can operate without pre-connected ejectors and instead, freeze the suction vapours in the "ice condenser". This system, designed for minimum energy requirements and maximum environmental protection, is employed for the distillation of edible oils by means of water vapour (deodorising), for freeze-drying and for solvent recovery.

Alkaline closed-loop systems (chilled water operation and cooling water operation) are further, environment-friendly systems developed specially for the edible oil industry. These closed-loop systems minimise waste water problems.