Positive Displacement Rotary Blower

Positive Displacement Rotary Blower

Two profiled rotors turn in a figure of eight shaped housing.

They are geared together so that they run very close to each other, but cannot touch.

There is no compression within the machine, it simply pushes gas into the system to which it is connected.

Machines with semi-screw profile rotors are also available, which reduces noise and vibration.

Typical Performance Envelope
  Imperial Metric
Minimum swept volume 50 cfm 85 m3/h
Maximum swept flow 70,000 cfm 120,000 m3/h
Maximum casing pressure 30 psi 2 bar
Maximum pressure ratio 2  
  • High speed range, typically ±35% from standard, gives easy flow controllability through speed control.
  • Valveless porting means no drop off in efficiency between overhauls, and no valves to maintain or break in service.
  • Low cost.
  • Good efficiency.
  • Oil free gas path.
  • Noisy.
  • Pulsating gas discharge.
  • High speed of operation.
  • Regular maintenance requirement.
  • High operating temperature.
Common Applications