Zaujímavé porovnanie použitia technológie od rovnakej spoločnosti Edwards Vacuum. Došlo k výrazným úsporám v spotrebe, hmotnosti,..

Replacing oil diffusion pumps by magnetic levitation turbomolecular pumps reduces cost of ownership by 90%

Magnetic bearings reduce wear and maintenance
Early turbomolecular pump designs used conventional mechanical bearings. While still used today, they have limitations arising from bearing wear and maintenance needs, especially in industrial production processes.

The introduction of magnetic bearings and magnetic levitation of the turbomolecular pump rotors has dramatically improved reliability. The rotor is entirely suspended by magnetic bearings, eliminating all contact with the rest of the pump. As well as giving very low vibration, eliminating this contact means that there is no bearing wear and hence no requirement for consequent pump maintenance.

For industrial applications a magnetically levitated compound turbomolecular pump using a Holweck molecular drag stage and fully bladed turbomolecular front end has enabled large capacity pumps to be produced. Capacities from 450l/s to 4500l/s are now available and are challenging the diffusion pump for industrial high vacuum processes.

Throughput capacities are significant - up to 2500sccm flow at crossover pressures of 0.5mbar with critical backing pressures up to 4mbar. This enables smaller backing pumps to be used compared to equivalent diffusion pumps.

Turbomolecular pumps can be mounted in any orientation and do not require inlet baffles or cold caps. Using a simple gate type valve means direct line of sight connection to the process chamber, eliminating any capacity losses through high conductance angle valves.




http://www.glassonweb.com/articles/article/536/
http://www.edwardsvacuum.com/