Published at Friday, August 24th 2018, 16:14:24 PM by Alfreda Kelley. Air Compressor. A rotary vane air compressor uses a rotor and a number of blades in radial slots in the rotor. I do not fully understand how this works, but it has something to do with the rotor turning and the blades sliding in and out of their slots as they keep contact with the housing wall. This somehow creates decreasing volume.