Extrusion Limits of O-Rings & Clearance Gaps
An o-ring is contained in a gland and forced to flow into the surface imperfections of the glands and any clearance gaps available to it. An o-ring can perform sealing by means of squeeze under low pressure conditions. The extent of extrusion depends upon the hardness of O-ring, the pressure, and the size of the clearance gap.
Limits of Diametral Clearance Against Fluid Pressure