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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 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.

Plan 72Plan 72 
API Plan 72 Panel and API Plan 72 Kit
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 inboard seal failure

Plan 72 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 55 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.

Contact your Authorized Sales and Service Center Back to Between Seal Plans