Mechanical seals with Metcar Grade M-444 antimony impregnated, carbon-graphite primary seal rings can seal low-viscosity liquids such as Freon refrigerants, liquid oxygen, liquid carbon dioxide, propane, ethylene and acetone. Low-viscosity liquids are difficult for mechanical seals because the hydrodynamic film they create between the two rubbing seal faces is extremely thin. The self-polishing characteristic of these rings enables the two materials to run in the required close proximity.
