Purge Reduction Seals (Velocity & Molecular Seals)


  • Designed to prevent flashback by minimizing air ingress from the top of the flare
  • Velocity purge seal mounted in base of flare tip and uses the velocity of the purge gas through the seal to sweep any atmospheric air in the flare tip
  • Molecular seal creates a labyrinth to more efficiently sweep any atmospheric air in the flare tip
  • Velocity seal reduces purge gas requirement by 94%
  • Molecular seal reduces purge gas requirement by 98%
  • Effective purge gas includes any gas that does not include oxygen and will not reach dew point at ambient conditions

Selection Criteria / Advantages

  • Velocity seal – lowest capital cost
  • Molecular seal – lowest operating costs
  • Molecular seal recommended for flare tips 24” and larger
  • Molecular seal can maintain an effective seal for up to 8 hours after loss of purge gas supply
  • Velocity seal provided with weep holes to allow drainage
  • Molecular seal complete with drain connection & inspection port
  • Both seals provide significant savings in operating costs
  • Extends flare tip life by minimizing burn back
  • No moving parts
  • Velocity seal standard on all Encore Combustion flare tips


Diameter: 24” – 144” + [610 – 3658 mm +]

Standard Materials:

Velocity Seal: 304SS
Molecular Seal: carbon steel or stainless steel

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