The carbon-graphite radial seal rings are manufactured by Metcar and are available in more than 150 grades of proprietary carbon/graphite material are available. Metcar’s packing rings are suitable for sealing both liquid and gases for a range of applications, including aircraft turbine engines, blenders and mixers, furnace exhaust blowers, and oil free piston compressors, as well as ship propeller shafts, steam turbines, and water pumps and turbines. The carbon-graphite radial seal assemblies help solve serious leakage problems that occur when stuffing box seals fail due to wear, thermal degradation, chemical attack, and dimensional stability problems with leather, plastic, composite or elastomeric elastic seal ring materials.
Two types of radial seal rings are available. The “close clearance” version is a one piece, solid ring made to fit with close clearance on the outer dimension of the rotating or reciprocating shaft. If the shaft is expected to experience thermal expansion, the carbon-graphite ring comes in a version that is shrink-fitted into a metal retaining ring, providing the carbon graphite/metal assembly the same thermal expansion rate as the shaft.
