Products

API Plan 55

API Plan 55

Unpressurized external buffer fluid system supplying clean buffer liquid for the outer seal of an arrangement 2 unpressurized dual seal. Buffer liquid is circulated by an external pump or pressure system.

A  From external source
B  To external source


Seal chamber details

1  From external source
2  To external source
3  Flush (F)
4  Liquid buffer OUT (LBO)
5  Liquid buffer IN (LBI)
6  Seal chamber


Example seal: EagleBurgmann LY9DZTT dual pusher mechanical seal.


P&ID according to API

Key

1  From external source
2  To external source

Features

  • Provides lubrication and cooling to the outboard safety backup seal.
  • The pumped fluid does not become contaminated.
  • The pumped media does not leak directly to the atmosphere.
  • Uses an external pump or pressure system to ensure buffer liquid circulation.
  • Provides buffer liquid circulation and cooling even though the process pump is in stand-by mode.

Application

  • For flashing services – for example light hydrocarbons, high vapor pressure fluids.
  • Can also be used for non-flashing service.
  • For services where product dilution is not acceptable.
  • Where a single system is to be utilized for multiple seals.

Remarks, checkpoints

  • Not to be used for contaminated and polymerizing media.
  • Sense the seal inlet and outlet line temperatures. Difference in the temperatures is an indication of proper flow.
  • Provide proper instruments like a flowmeter which will indicate outboard seal leakage when the flow increases. Also provide suitable pressure reduction as well as non-return valves in the flushing pipeline.
  • The buffer liquid shall be maintained at a pressure less than seal chamber pressure and less than 2.8 bar (40 PSI).
  • Ensure the compatibility of buffer liquid with the pump media.
  • These systems may need additional engineering depending on application.

Pump media characteristics

  • High temperature
  • High vapor pressure, flashing media
  • Clean, non-polymerizing
  • Hazardous / environmentally harmful if leaked directly to the atmosphere.

Location, function

  • Between seals
  • Buffer system (psealchamber > pbetweenseals)
  • Flushing and cooling

Configurations

2CW-CW

 

API 682 4th Edition

Contact us

Follow the direct link to your API 682 4th ed. contact

Show locations

API piping plan tool

Download the free EagleBurgmann API piping plan tool and benefit from useful and practical information

PDF download - 4.0 MB
Newsletter

Excellence in Practice

With our free e-mail newsletter „Excellence in Practice“, you will receive first-hand information about current products, services, references and worthwhile industry insights.

True