Centrifugal Compressor

Centrifugal Compressor

An impeller is attached to a rotating shaft within a cylindrical housing. Gas drawn into the housing near the centre, is then thrown towards the perimeter.

The imparted velocity of the gas causes a pressure rise and flow. Multi-stage machines direct the gas back to the centre of the next stage. Differs from centrifugal blower in that pressure containment housing is much stronger.

Two main layouts are Integrally Geared type, where several stages are mounted radially on a central speed increaser gearbox, and Barrel type, where stages are all mounted on a single shaft.

Typical Performance Envelope
 
  Imperial Metric
 
Minimum swept volume 10,000 cfm 17,000 m3/h
 
Maximum swept flow 180,000 cfm 300,000 m3/h
 
Maximum casing pressure 2,200 psi 150 bar
 
Maximum pressure ratio 4  
Advantages
 
  • High efficiency.
  • Vibration free operation.
  • Pulsation free gas discharge.
  • Valveless porting means no drop off in efficiency between overhauls, and no valves to maintain or break in service.
  • Flow control through inlet guide vanes.
  • Very long maintenance intervals.
  • No lubrication oil in gas.
Disadvantages
 
  • Noisy. A sound enclosure is normally required.
Common Applications