Dry running mechanical seals are used on large, vertical mixers to seal the clearance between the agitator shaft and the mixer housing at the location where the shaft enters the top of the mixer. Primary seal ring wear life has been a problem with these mechanical seals because they must run dry with high shaft run-out. Available fully machined to the user's specifications, Metcar Grade M-58 primary seal rings can be used in temperatures between -30 and 800°F (-34 to 427°C).
For pharmaceutical applications, several Metcar grades have passed the tests required for U.S. Pharmacopeia Class VI approved materials.