方案十六

　　What

　　what.

　　Pressurized barrier fluid circulation by external system .

　　Why

　　Isolate process fluid

　　Zero process emissions .

　　Seal cannot induce circulation

　　Where

　　Used with pressurized dual seals .

　　High vapor pressure fluids ,light hydrocarbons

　　Hazardous /toxicfluids

　　Heat transfer fluids

　　Dirty /abrasiveor polymerizing fluids

　　Mixers /agitators.

　　Preventative Maintenance

　　Piping loop must be fully vented before starting

　　Circulating system must be pressurized and energized at all

　　times .Barrier fluid must be compatible with process .

　　Circulating system level indicator shows both inboard and

　　outboard seal leakage .