Not sure what you're driving at XR8TT, but to say the Eaton is a screw compressor because it has twisted rotors, and looks a bit like a screw isn't correct. That first illustration in my post below was just the "classic" Roots from a century ago, and has little or nothing to do with present day Roots technology. Eaton define all their compressors as Roots
Whipple are a packager for Lysholm, who are owned by Opcon Autorotor, and their compressors are screws.
Kenne Bell are a packager for Opcon-Autorotor, and their compressors are screws.