Rotary Lobe Air Compressor:

The rotary lobe-type, described in Figure, characteristics two mating lobe-type rotors mounted in a case. A lobe is gear driven at close clearance, other than without metal-to-metal contact. Suction to the unit is situated whereas the cavity made through the lobes is largest. Since, the lobes rotate then the cavity size is decreased, causing compression of the vapor within. A compression continues until the discharge port is reached, at that point the vapor exits the compressor at a higher pressure.

Figure: Rotary Lobe Air Compressor