A Roots vacuum pump achieves suction and discharge by means of a pair of figure-8 rotors rotating counter-rotatively at constant speed within the pump casing. Each rotor is supported by two bearings, and a pair of synchronizing gears maintains a constant relative position between the two rotors. Clearances are maintained between rotor and rotor, rotor and casing, and rotor and side covers. Since there is no friction in the working chamber, no lubrication is required.

The rotor support employs a reliable backlash-free structure. Rotating parts are subjected to thorough dynamic balancing, and high-precision helical gears are adopted, ensuring smooth operation, low noise, and high reliability, allowing long-term operation under high pressure differentials. The dynamic seal is robustly designed with imported oil seals, limiting shaft seal runout to ≤0.02mm, thus preventing oil leakage at the shaft seal.

The pump is manufactured with CNC machining centers. Sealing between casing and side covers, and between side covers and end covers, is achieved with O-rings, and location is ensured by dowel pins, providing good part interchangeability and easy maintenance. The pump is designed with one inlet port and three exhaust ports for convenient installation and use.

A Roots pump cannot be operated alone and must be used in series with a backing pump. Screw pumps, oil-sealed rotary pumps, and liquid ring pumps can be used as backing pumps. In particular, when screw pumps or liquid ring pumps are used as backing pumps, the arrangement is especially suitable for pumping large volumes of condensable vapors.