Metcar Grade M-58 has received approval from the Food and Drug Administration so that it can be used in food contact applications. This will permit the use of Metcar Grade M-58 in dry running, food mixer seals to provide lower seal friction and longer seal wear life. The electro-graphite base material from Metallized Carbon Corp., Ossining, N.Y., contains an additive to reduce friction and improve the dry running wear rate.
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.