In this article, we are going to look at five of the most common phenomena involved with polymer seal
failure, and what causes are behind the failure. Lets start with extrusion.
Extrusion
One of the common causes of seal failure is extrusion. If the extrusion took place on the static side of
the seal, then either the back-up ring is too small or the support surface is somewhat uneven. If it is
extruded on the dynamic side, then there could be one of three causes: extreme pressure, worn
bearings, or too large a gap between the mating surfaces.
Fracturing
Fracturing can take several forms, such as chunks missing or long cracks. If you see entire chunks
missing from the dynamic side, the cause is most likely excessive back pressure. If you see the pressure side of the seal broken and burned, the cause could well be the explosion, at high pressure, or residual air. Long cracks appearing in the V-portion of a seal can result from frequent spikes in pressure or too low a temperature at system start up.