(1) a large pumping speed over a wide pressure range;
(2) the rotor has good geometric symmetry, so the vibration is small and the operation is stable. there is a gap between the rotor and between the rotor and the casing, no lubrication, and the friction loss is small, which can greatly reduce the driving power, thereby achieving a higher rotational speed;
(3) oil seal and lubrication are not required in the pump chamber, which can reduce the pollution of the vacuum system by oil vapor;
(4) there is no compression in the pump chamber, no exhaust valve. the structure is simple and compact, and is insensitive to dust and water vapor in the pumped gas;
(5) the compression is relatively low, and the effect on hydrogen gas pumping is poor;
(6) the surface of the rotor is a curved cylinder with a complicated shape, which is difficult to process and inspect. it has been widely used in smelting, petrochemical, electrician, electronics and other industries.
