Spiral Groove Face Seal Concepts; Comparison to Conventional Face Contact Seals in Sealing Liquid Sodium (400 to 1000 Deg F)

Abstract

Conventional face contact seal performance was improved by incorporation of the spiral-groove geometry. Both conventional face contact seals and seals with spiral grooves were used to seal liquid sodium at a pressure of 20 lb per sq in. gage (14.0 N/cm2 gage), and a sliding velocity of 79 fps (24 m/sec). In comparison with conventional face contact seals, seals with spiral grooves had negligible leakage. The wear and contact patterns indicated that the spiral-groove seal operated with separation of the sealing surfaces, which is necessary for long life. Supporting studies (sealing oil) on face contact seals employing the spiral-geometry are discussed. Successful low-leakage operation was not achieved with conventional face contact seals having carbide seal seats and nosepieces (hard on hard). Thermal and pressure distortions caused edge contact, wear, and scoring. Conventional face contact seals having seal seats and nosepieces with wear-in properties (soft on hard) showed more leakage than those with carbide sealing surfaces.