Plan 53C


Pressurized barrier fluid system with pressure maintained and fluctuations compensated for in the seal circuit by a piston type accumulator


  • Circulation is maintained by a pumping ring when equipment is energized, by thermosiphon effect when idle
  • Heat is removed from the system by a heat exchanger (air or water cooled)
  • Seal life optimized by maintaining clean fluid film between the seal faces
  • No media leakage to the atmosphere
  • Allows use of double seals lacking reverse balancing feature at the inboard seal when there is variable seal chamber pressure

For use:

  • Where no leakage to atmosphere is allowed; hazardous, flammable, toxic fluids
  • For dirty, abrasive or polymerizing fluids where media is unsuitable as a lubricant for the inboard seal faces
  • Maintains constant pressure differential between the seal pot and the seal chamber (process) where pump pressure varies during operation




  • Connect reference line from the seal chamber to accumulator and keep it open
  • There will always be some leakage of barrier fluid into product – verify compatibility
  • Vent the system properly before start up
  • Barrier fluid contamination can cause corrosive degradation of equipment