CF-UHV Ultra High Vacuum Junctions
Novotek CF components are manufactured according to ISO 3669. All components manufactured by Novotek are 100% leak-tested and have leak rates better than 10–10 mbar. l/s. Standard sizes are NW 16 to 250. Nominal widths of up to 400 can be manufactured upon request. The ultra high vacuum range (UHV) designates the pressure range <10–8 mbar. To reach and maintain this low pressure range, a very low outgassing rate is required in the vacuum system. This is achieved by using material with as low a desorption, diffusion and permeation rate as possible and by preventing unventilated cavities and gaps and by using vacuum-compatible cleaning systems.
Sealing principle: The CF connection is sealed off by the cutting-edge profile in the flange and a copper sealing washer. The copper sealing washer is inserted in the flange groove and, at the same time, centers the flange pair. When bolting the flanges, the cutting edges of the flanges for sealing are pressed deeply into the soft sealing washer, whereby the metal “flows away” radially and is pressed on the outside against the flange groove and limited.
Design features: The flanges of the CF components are designed according to ISO 3669. They are compatible with the Con-Flat® flanges of other leading manufacturers. Retrofitting in Novotek CF systems or systems from other manufacturers is possible. The standard material used is low-carbon high-grade steel with material number 1.4306 (304L). For the most common flanges and components, higher quality high-grade steels 1.4404 (316L) can also be used. Due to the bake-out capacity required in UHV technology, sealing of the CF flanges is by means of a flat seal made of oxygen-free (OFHC) copper. The contact pressure is generated by diametrical tightening of the screws. The copper seal can only be used once. When baking out CF connections, ensure that heating up and cooling is carried out uniformly and relatively slowly.
Materials Details and Specifications operation temperatures, sealing materials and clamping elements