The danger of O-Ring extrusion through the play between the seal surfaces (figure 9.4), is one of the factors that conditions the use in the dynamic applications, as already described amply in chapter 6. The extrusion provokes deep lacerations (figure 9.5) and the exiting of the ring from the housing, with the consequential loss of the system seal capacity.
a) O-Ring at rest
b) O-Ring during an attempt at extrusion
Damaged O-Ring following extrusion
The causes of the extrusion are mainly linked to the finishing and the element tolerance that form the system, to the diametric play and to the exercise pressure. Also the temperature plays a fundamental part modifying the elasticity and the compound's viscosity.