In a vacuum pump according to the invention, the rotor is held inside the stator by radial magnetic bearings, and its radial movements are limited by one or more landing mechanical bearings each made up of a rotor rolling bearing race and a stator rolling bearing race. At least one coaxial ring of elastomer in the shape of a torus is inserted between the outside peripheral surface of the stator rolling bearing race and the stator itself to constitute a damped elastic connection which significantly increases the reliability and the service life of the landing mechanical bearing.
An auxiliary bearing assembly for selectively engaging a shaft, preferably in an energy storage flywheel system, is configured to include a vibration damping seal, and an axial preload spring. The vibration damping seal damps out vibrations from the rotating group, following engagement of the auxiliary bearing assembly, while the rotating group is spinning down. The axial preload spring absorbs any differential thermal expansion or contraction that may occur between components.
An ultra-high speed vacuum pump evacuation system includes a first stage ultra-high speed turbofan and a second stage conventional turbomolecular pump. The turbofan is either connected in series to a chamber to be evacuated, or is optionally disposed entirely within the chamber. The turbofan employs large diameter rotor blades operating at high linear blade velocity to impart an ultra-high pumping speed to a fluid. The second stage turbomolecular pump is fluidly connected downstream from the first stage turbofan. In operation, the first stage turbofan operates in a pre-existing vacuum, with the fluid asserting only small axial forces upon the rotor blades. The turbofan imparts a velocity to fluid particles towards an outlet at a high volume rate, but moderate compression ratio. The second stage conventional turbomolecular pump then compresses the fluid to pressures for evacuation by a roughing pump.
