EVAC Flanges and Fittings
They provide a number of benefits over elastomer seals: reduced outgassing, no permeation, no hydrocarbons, resistance to radiation and short half-life. EVAC seals are used in high-energy physics, other UHV applications and, in some circumstances, cryogenic applications. EVAC seals are reliable in high vibration or temperature cycling environments. EVAC chain clamps and tapered flanges are the standard vacuum flange for many Japanese semiconductor equipment manufacturers. The advantages over using the standard ISO flange are the time and space savings during assembly and the flexibility to form high vacuum or UHV seals.
To install a metal seal on an existing KF flange, simply remove the standard clamp, centering ring and O-ring assembly. Replace them with an aluminum knife edge seal and chain clamp. (See diagram.). Standard ISO claw clamps can be used with EVAC aluminum seals to convert ISO flanges from high vacuum to UHV. Tapered flanges are similar to KF flanges and are available in 80 and 100mm sizes from stock. Chain clamps are used to form either elastomer or metal seals with tapered flanges.