Detailed technical content
USIT seals by combining a rigid support ring with an elastomeric element
A rubber-bonded metal washer, or USIT, combines a metal ring with an elastomeric element in the sealing area. When the joint is tightened, the elastomer is compressed to form a seal against the contact surface, while the metal ring provides location and limits deformation.
DEDE lists typical applications in pipe connections, fittings, threaded plugs and static sealing assemblies in pressure systems. This is a face seal, so the quality of the seating surface and the joint’s tightening force directly affect sealing performance.
Nominal size must suit the bolt/thread and seating surface
Do not select a USIT by its outside diameter alone. Compare the hole size, outside diameter, thickness and nominal joint size. If the washer is too large or too small for the seating surface, the elastomer may not be compressed in its intended area.
The elastomer must still be compatible with the medium
The metal ring provides rigidity, but the elastomer is the area that directly performs the sealing. Its material must therefore suit oil, fuel, water or another medium, as well as the operating temperature. When transferring a seal from one system to another, do not assume that all USIT washers of the same size are completely identical.
