1. Phenomena involved and industrial applications

1.1 Principle

A seal (figure 1 ) is essentially made up of two rings (indices 1 and 2), moving in relative rotation, in contact on the annular surfaces of their ends. The contact of the two annular surfaces in relative sliding motion ensures the separation of two fluid media, one inside, the other outside the rings. A secondary seal is provided between each ring and its support (shaft or frame element). To enable the two rings to be aligned despite any geometric defects, at least one of the two rings is linked to its support by a deformable connection. This is referred to as a floating ring. When the ring rotates, we call it a rotor, and when it doesn't, we call it a stator.