Oil Flooded Screw Compressor

Oil Flooded Screw Compressor

Twin screw shaped meshing rotors are mounted in a figure of eight shaped housing, which has suction and discharge ports at either end.

As the rotors turn they form a space that traps gas, the space travels down the length of the housing, and because of the profile of the screws, is compressed as it goes.

Oil is flood injected into the compression space to lubricate the bearings and screws, and to absorb the heat of compression. The oil and compressed gas mixture subsequently passes into a de-oiling vessel.

The oil is then cooled and filtered and goes back round the cycle once again.

Typical Performance Envelope
 
  Imperial Metric
 
Minimum swept volume 150 cfm 250 m3/h
 
Maximum swept flow 10,000 cfm 17,000 m3/h
 
Maximum casing pressure 500 psi 100 barg
 
Maximum pressure ratio 20  
Minimum pressure ratio 2  
Advantages
 
  • Oil flooded lubrication system absorbs heat of compression, thereby allowing very high compression ratios. Film of oil protects internals from attack by aggressive constituents.
  • Pressure ratio controllable by slide valve, which lengthens discharge port in the direction of the suction port.
  • Flow controllable by slide valve on suction port and speed variation.
  • Vibration free operation.
  • No special foundation required, lowering civil costs.
  • Pulsation free gas discharge.
  • Valveless porting means no drop off in efficiency between overhauls, and no valves to maintain or break in service.
Disadvantages
 
  • Intimate contact between lubrication oil and compressed gas.
Common Applications