Hybrid-Ceramic Circumferential Carbon Ring Seal

The key to achieving the combination of low leakage, high reliability and long life in un-cooled high speed core engine air/oil carbon ring seals lies primarily in the combination of materials utilized in the critical seal components coupled with the seal design. A unique hybrid-ceramic circumferential high-speed carbon ring seal journal (runner) designed in concert with a segmented arch-bound or fractured ring stationary carbon seal provides the material enabling technologies to achieve extraordinary clearance control capability throughout the gas turbine engine operating range. Such seal technology has achieved over 20M successful seal hours in over 40,000 seal assemblies installed in Honeywell's TFE-731 man-rated primary propulsion turbo-fan engine and, can be designed for either retrofit or new engine applications in both air/oil and air/air seal locations. With seal air leakage values comparable to carbon face seals, the hybrid-ceramic carbon ring seal provides significant improvements in both reliability and life which to date have enabled a 96% reduction in unscheduled engine removals from the 10,000+ engine TFE-731 fleet since introduction into production in 1996.