Plan 11


Product recirculation from pump discharge through a flow control orifice


  • Can prevent product vaporization by elevating seal chamber pressure
  • Self-venting plan for horizontal pumps
    Default API plan for most single seals

For use:

  • With clean, non-polymerizing fluids at moderate temperatures


  • Recirculation flow rate, heat removal and orifice size must be calculated
    Orifice size should be at least 1/8”
  • Differential pressure between pump discharge and seal chamber must be determined to ensure proper fluid flow
  • Do not use with media containing solids and/or abrasives pocket in seal chamber