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.
Metcar grade M-58 is an electro graphite base material that contains a special additive to reduce friction and improve the dry running wear rate. Available fully machined to the customer’s specifications, primary seal rings made from this material can be used at temperatures between -34oC and 425oC.