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API Plan 31 Flush with Cyclone Separator

API Plan 31 is used to remove solids from the flush stream by incorporating a cyclone separator into the flush tubing. Flow is routed from the discharge side of the pump through the cyclone separator. Clean flush fluid leaving the separator is routed to the seal chamber while fluid containing the solids is routed back into the suction side of the pump. In order for Plan 31 to be effective, it is recommended that the specific gravity of the solids be at least twice the specific gravity of the flush fluid.

Plan 31
API Plan 31
Kit components shown solid and include some optional components.

This plan:

  • Removes heat from the seal chamber
  • Ensures proper pressure in the seal chamber in order to prevent pumped fluid from vaporizing
  • Allows seal chamber to be self-venting when used with horizontal pumps
  • Removes solids from the flush fluid

Plan 31 is available as a kit of components ready for field assembly. Kit contents may include:

  • Swagelok tube fittings
  • Flange adapters
  • Pipe fittings
  • V series 2-valve manifold
  • Bimetal thermometer
  • TTW series thermowell tee
  • PGI series gauges
  • Tubing
  • Pressure transmitter
  • Cyclone separator
  • Pipe nipple

See page 25 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.

Request more information about Swagelok assembliesBack to Process Side Plans