API Plan 72 Buffer Gas
API Plan 72 supplies a buffer gas from an external source between the inboard and outboard seals. For reliable operation, gas seals require a constant supply of clean, dry gas, typically nitrogen. The seal support panel contains a coalescing filter to remove any moisture and particulate present in the supply of plant nitrogen. The clean, dry nitrogen dilutes process leakage from the inboard seal and sweeps it to a collection system. For condensing leakage, a Plan 75 is used as the collection system; for non-condensing leakage, a Plan 76 would be used for the collection of primary seal leakage. A pressure regulator on the panel regulates the nitrogen prior to entering the seal chamber. Nitrogen pressure should not be more than 10 psi (0.68 bar) and is typically regulated
- Supplies the gas seal with a clean, dry buffer gas, typically nitrogen
- Serves as a containment seal in the event of primary seal failure
See page 51 of the Mechanical Seal Support Systems Applications Guide for additional details.