First, the concept and classification of Roots vacuum pump: 1, concept: Roots vacuum pump is a rotary volumetric vacuum pump. Its structure is evolved from a Roots blower. First appearing in Germany in 1944, it was used as a mechanical booster pump to accommodate vacuum melting systems with large pumping speeds in the 10-1000 Pa pressure range. 2, classification: Roots vacuum pump according to the different working pressure range, divided into: (1), the straight row of atmospheric vacuum Roots pump; (2), the vacuum Roots pump (mechanical booster pump); , High vacuum multistage Roots pump. The largest amount of domestic vacuum Roots pump. Second, the Roots vacuum pump features: Compared with other oil-sealed vacuum pump has the following characteristics: 1, a wide range of pressure in the larger pumping speed; 2, the rotor has a good geometric symmetry, so the vibration is small, running smooth. Rotor and between the rotor and the shell are gaps, without lubrication, friction loss, can greatly reduce the drive power, which can achieve high speed; 3, the pump chamber without oil seal and lubrication, can reduce the oil vapor on the vacuum System pollution; 4, pump chamber without compression, no exhaust valve. The structure is simple and compact, insensitive to the dust and water vapor in the gas being sucked; 5, the compression ratio is low, the hydrogen pumping effect is poor; 6, the rotor surface is more complex shape curve cylinder, processing and inspection more difficult. Roots vacuum pump in recent years at home and abroad to get faster development. In smelting, petrochemicals, electrician, electronics and other industries have been widely used.