PTFE Back-Up Rings

Additional Details

With proper mechanical design and materials of construction, O-rings generally serve as effective seals for reciprocating or rotating shafts, over wide ranges of temperature and pressure; they also offer the advantages of sealing in both directions. One big drawback of O-rings, however, is their tendency to extrude under pressure into seal clearances (see Fig. I). Degree of extrusion depends on hardness of the O-ring, clearance between parts, and fluid pressures involved.