The ScrewLine SP 250 is a dry-compressing, screw-type vacuum pump designed for use in industrial processes. Smaller than the 630, it has a pumping speed of 250 m3/hr, and it replaces oil-sealed rotary vane and rotary piston vacuum pumps. The rotors are fitted to two horizontally arranged shafts that revolve around the pump chamber. To achieve higher speeds at lower pressures, users have the option of combining Roots pumps.
Leybold Vacuum GmbH, http://www.leybold.com/.