A Roots type blower is a positive displacement lobe air/gas pump which operates by pumping a gas/fluid with a two/three lobes in a specially shaped casing. The gas pulled in and trapped in the pockets between the lobes and casing and then drawn around from the intake side to the exhaust side.

Roots blowers can deliver relatively substantial consistent volumes at pressures up to 1 Bar and vacuums up to 0.5 Bar.
Roots blowers have many applications like pneumatic conveying, water treatment and aeration.