API Plan 72/76 Buffer Gas and Noncondensing Leakage Collection
This panel is a combination of API Plan 72 and Plan 76. The Plan 72 side supplies a buffer gas from an external source between the inboard and outboard faces of a dual seal. 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. The Plan 76 side collects the 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 to the alarm point on the leakage collection system, or at least 5 psi (0.34 bar) above the regular pressure of the flare line.
Panel and kit shown with some optional components.
This plan:
- Supplies the gas seal with a clean, dry buffer gas, typically nitrogen
- Serves as a containment seal in the event of primary seal failure
- Monitors inner seal leakage that does not condense at ambient temperatures
Plan 72/76 is available as an assembled panel. The associated field installation kit for use in connecting the panel to your system is also available. Panel contents may include:
- Swagelok tube fittings
- 43G series ball valves
- V series 2-valve manifold
- R series relief valves
- CH series check valves
- FC series filter
- G2, M1, and M2 model flowmeters
- KPR series regulator
- PGI series gauges
- Swagelok pipe fittings
- Pressure transmitter
- Pressure switch
- Mounting panel
- Brackets/miscellaneous hardware
See page 71 of the Mechanical Seal Support Systems Application Guide for additional details and ordering information. Contact your authorized Swagelok sales and service center for information on optional components.