Unpressurized buffer fluid circulation by external system
Outboard seal acts as a safety backup to the primary seal
Zero to very low process emissions .
No process contamination is allowed
Additional heat removal from the inner seal .
Seal cannot induce circulation .
Used with unpressurized dual seals .
Fluids that may solidify in contact with atmosphere .
Piping loop must be fully vented before starting
Buffer fluid must be compatible with process leakage .
Accumulated process leakage should be routed to a recovery