Roots vacuum pumps RUVAC, which are also called Roots blowers, are rotary plunger type pumps where two symmetrically shaped impellors rotate in opposite directions inside the pump housing. Roots pumps are used where great volumes have to be pumped. In combination with backing pumps, which compress against the atmosphere, these pumps offer the are capable of improving the attainable ultimate pressure of a pump system by a factor of 10. With two Roots vacuum pump stages and a corresponding backing pump it is possible to attain pressures in the range down to 10-5 mbar (0.75•10-5 Torr). Regarding the motor concept RUVAC pumps are offered in different models.
Usually RUTA vacuum systems are combinations of Roots vacuum pumps of the type WA, WS and RA or WAU and WSU with integrated bypass line with oil-sealed backing pumps for conventional generation of the vacuum. Single stage arrangements are capable of delivering pumping speeds of 250 to 16,000 m3/h (147 to 9,424 cfm). Higher pumping speeds can be attained by paralleling several pumps. The attainable operating pressures depend on the number of pumping stages.
Effective as of September 1, 2016, Atlas Copco AB (Stockholm, Sweden) owns the former Oerlikon Leybold Vacuum, renamed to Leybold.