EVAC ISO CeFiX® connections are available in sizes NW16 up to NW250, as standard. This system has been developed completely by EVAC, allowing customers to get a EUHV leakproof connection within seconds.
CeFiX® is the next generation of the old Conflat® (CF) system. The main difference between both is the way of compressing the metal gasket.
The CF knife edge makes a circular line imprint into the gasket. Used a second time, this imprint is always shifted slightly in the micrometer range, due to mechanical tolerances. The intersecting points of two or more imprint circles are causing vacuum leaks, subsequently.
Besides its particle generating nature, the one time usability is the main disadvantage of the CF knife edge.
The completely particle-free area-pressing mechanism of the CeFiX® system allows for reuse of the seals, as the smooth overlapping areas do not exhibit the leaking deficiencies of the deep CF groove imprints. A further advantage of the wide overlapping area with a wide 200 … 400µm crossection is its extensive thermocycling capability with a sheer range of -271 … +450 degC, usually breaking the fragile CF knife edge just after one cycle.
Needless to mention, that such a robust EUHV connection (< 10E-11 mbar, <1 nPa) can carry overpressure of up to 300 bar (using especially certified chainclamps with TÜV approval). This is achieved by using very hard nickel seals, even impossible to penetrate by a CF knife edge, but easily to be compressed using the gear-type force-multiplying mechanism of CeFiX® chain clamps. This technology finally requires only 50% of the CF compression force at seal surface in order to achieve gas-tight intermetallic diffusion bonds.