(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.