Centering Rings for ISO KF/LF Flanges

Stainless steel centering ring assemblies with Viton^® O-rings.
These ISO centering rings are used for mating two High Vacuum (HV) NW ISO (KF,LF) flanges.

 

Centering rings are placed between two ISO flanges with matching outer diameters. The tallest part of the stainless steel centering rings rests inside a centering ring locater groove or counterbore.  The Viton O-ring rests on the flat polished surface outside the locater groove or counterbore and the vacuum seal is made by compressing the O'ring between the mating flanges.  Typically this is done by alternately wrench-tightening opposing pairs of bolts or tightening the hinged clamp until the first metal-to-metal contact is made between the inner surfaces of the flanges and the spacing edges of the centering ring.