MAPRO Positive Displacement Blowers consist basically of a pair of Tri-lobe rotors, mounted on parallel shafts, rotating in opposite directions inside a properly shaped casing closed at the ends by side plates.
The two Tri-lobe rotors are synchronized by a pair of timing gears. As the rotors rotate, air is drawn into the inlet side of the casing,
is moved from the inlet to the outlet side by the free volumes between rotors and stator and finally is forced out of the outlet side against the connected system pressure.


  • Stators, rotors, side plates and covers are totally made of grey cast iron. The covers of model ML175 are made of aluminum alloy so that to increase the efficiency of the cooling of the lubricating oil;
  • shafts are in carbon steel and rotors are shrinked on the shafts;
  • the timing gears are helical type with involute profile and made of alloy steel, with hardened and ground teeth;
  • sealing of the conveyed gas on the rotor shafts is assured by labyrinth seals and segments;
  • bearings and timing gears are lubricated by the oil splashed by disks fitted on the rotor shafts.


MAPRO Positive Displacement Blowers are suitable for all those applications requiring considerably higher flow rate than that which can be achieved using side channel blowers and till 4200 m3/h, and with discharge pressure till 1000 mbar g.
The most common fields of application are:

  • air injection in the oxidation tanks of the wastewater treatment plants;
  • pneumatic conveying;
  • air injection in saturated soils to promote biodegradation of the contaminants (Biosparging or Bioventing).

There is no contact of the rotating parts during operation of the Blowers. There is therefore no friction between the two rotors and between the rotors and the stator and thus no internal lubrication is needed. The gas moving through the machine remains uncontaminated and completely oil-free.