Vacuum Systems with Ejectors
A vacuum system typically consists of one or more stages of ejectors with intermediate condensers which produces the condensation of the vapors coming from the previous stage.
The suction pressure varies in a range from 0.100 to 200 Torr. For higher absolute pressures, a single steam ejector is enough, that is, only one stage.
When vacuum systems with steam ejectors, consist of several stages, air, gas and steam drawn out from the facility where vacuum is being created, undergo a compression in each stage. The number of stages equal to the number of ejectors connected in series.
Intermediate condensers are use for condensing motive steam from ejectors, additionally to the steam aspirated from the facility where vacuum is being created thereby suction load is reduced in each stage. These condensers can be either mixing or direct contact as well as surface.
The required amount of stages depends on the level of vacuum required in accordance with the following figure:
Additionally the following possibilities can be taken into account:
- Including a pre-condenser. Its purpose is to reduce the suction load in the first stage by condensation of the vapors of the group entry.
- Including a post-condenser. Its purpose is to recover the condensate from motive steam at the last stage. This arrangement is used for vacuum groups with air vent in turbine condensers.
- Intercondenser multi-shell. Condensers can be designed with several shells which share tubes side. Each stage of ejectors discharges into each one of the shells. This arrangement creates a more compact vacuum group.
EQUIREPSA supplies with vacuum systems with ejector completely custom and according to the specifications and needs of each client (loose equipment, complete skids with valves and instrumentation, etc..)