Description: Plan 74 is an external control system supplying
BARRIER gas (typically Nitrogen) at greater pressure than the
process pressure being sealed, to an Arrangement 3 dual gas seal.
Objective: Prevent process from
leaking to the atmosphere.
Remove moisture, filter the gas
and regulate the pressure to the
seal. Best for hazardous, nonpolymerizing,
nonâoxidizing
fluids, light hydrocarbons and
vapors.
Advantages: For processes that
do not tolerate a liquid barrier.
Can be used with LIFT OFF seal
faces that generate no heat or
wear and can have significantly
increased seal life. Lower cost
and maintenance than dual
liquid systems.