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Atmospheric Air Ejector / Liquid Ring Pump Ejector for Condensor Vacuum

Thermal Powerplant condensors often operate at very low pressures as it enables the last turbine stage to maximize steam expansion and in turn maximize energy extraction from steam.
Because of the complexity of the power plant piping and the vast number of joints it is impossible to avoid air leakage into the system. This leaked air tends to collect in the condenser and raises its pressure thus affecting operation. Hence external vacuum has to be maintained in the condenser to remove the leakage air and maintain vacuum.
Thus the condenser vacuum system has a critical role and its performance directly impacts the powerplant efficiency.
Generally the required vacuum in the condenser is equivalent to the saturation pressure of the condensate and varies between 55~80 mbar depending upon the geographical region.
The max vacuum created by the Liquid Ring Vacuum Pump is limited by its sealing water temperature. The sealing water temperature varies to some extents in different parts of the world but has a large impact on pump performance.

RegionSealing Water Temp °CMax vacuum
Europe & North America20 ~ 25mbar: 32
Torr: 25
South Asia, North Africa & Australia30 ~ 35mbar: 55
Torr: 40
Middle East35 ~ 40mbar: 70
Torr: 55



Additionally as the pumps approach the max vacuum level their suction capacity drops drastically.
Hence as the required levels of condenser vacuum and liquid ring pump capacity don’t match a liquid ring vacuum pump cannot be used directly for maintaining the condenser vacuum
In such cases an air ejector is mounted on the Liquid Ring Vacuum Pump to boost its vacuum. This air ejector uses air from the atmosphere as the energy input and hence is known as Atmospheric Air Ejector. As it is mounted on the Liquid Ring Vacuum Pump it is also known as Liquid Ring Pump Ejector.

The speciality of this Atmospheric Air Ejector and Liquid Ring Vacuum Pump combination is that the Ejector does not require any Electrical input or compressed air or pumped liquid for its operation.
This Atmospheric Air Ejector and Liquid Ring Vacuum Pump combination system can deliver vacuum upto 8 – 20 Torr i.e 10 – 26 mbar and easily satisfy the condenser vacuum requirement

Benefits of the Atmospheric Air Ejector / Liquid Ring Pump Ejector in maintaining condenser vacuum.
• Ability to easily handle a mixture of air + water vapour mixture coming from the condenser.
• Use Atmospheric Air as energy input / fuel – hence no additional infrastructure needed for operation.
• Atmospheric Air ejectors do not contain any moving parts and have large internal passage areas, hence are not vulnerable to liquid entry or clogging by solid particles.
• As they have no moving parts, maintenance requirements are very less. Also it reduces largely the risk of abrupt breakdowns, helps in maintaining the regular production schedule