Description: Plan 72 is an external control system supplying a
“whisper” of BUFFER gas (typically Nitrogen) at less pressure
than the process pressure being sealed, to an Arrangement 2
dual gas seal, with a dry
running containment seal.
Used alone to dilute seal
leakage or in conjunction with
Plan 75 or 76 to help sweep
seal leakage into a closed
collection system.
Objective: To reduce human
and environmental contact in
the event of a primary seal
failure. Remove moisture, filter
the gas and regulate the
pressure to the seal.
Advantages: Zero to very low
process emissions.