It is often necessary to transmit mechanical movements into vacuum systems. There are few basic principles to execute the required movements such as rotation or translation working without or with magnets:
Elastomer and bellows sealed
Elastomer sealed systems are suitable for HV applications, while UHV processes require edge welded bellows sealed designs. Bellows sealed feedthroughs enable highest precision and reproducibility. In addition, these systems can be assembled completely free of magnetic fields being an essential criteria for many fields of application.
The rotary or linear motion is transmitted by a mechanism on atmosphere side via a magnetic coupling to a shaft in the vacuum. The one-piece housing is open to the vacuum only. Strong magnets ensure a rigid coupling, which enables the transmission of high torques and high axial loads.
Magnetofluid sealed rotary feedthroughs
Magnetofluids with low vapor pressure are used for this purpose. Specially designed pole shoes and strong magnets retain the magnetofluid in the shape of liquid O-rings. The housing bundles the magnetic fields inside the rotary feedthrough, so that only a negligible magnetic stray field will remain outside.