Seal Support System

API PLAN 53A

API Plan 53A uses an external reservoir to provide external pressurized liquid (barrier liquid) for arrangement 3 Seals. The reservoir pressure is maintained by a gas, usually nitrogen at a pressure 2Kg/Cm2 above stuffing box pressure. It consists of a reservoir with capacity of 20 Liters, cooling coils level gauge, level switch / level transmitter, pressure gauge, pressure switch / pressure transmitter, Nitrogen connection, hand pump, support pipe with pipe fittings

Objective

It is used in services where the process fluid leakage is eliminated.
It is economically used where the stuffing box does not 10 kg/cm2 (g) and the box temperature is up to 150oC.
It is used where safety is of utmost importance and the media being sealed is extremely hazardous.
It can also be used in application where additional heat removal from the inner Seal is required.

Advantages

Economical of all the plan 53 plans
There is no chance of the hazardous process liquid to leak provided barrier pressure is maintained
Enhanced cooling of the inner and outer Seals.
With flanged bottom connections, the cooling coils can go for maintenance.
An orderly shut down & repair of Seals is possible in case of failure of inner Seals.
Monitoring of both inner seal leakage and outer seal leakage is possible through switches or transmitters linked to DCS. (distributed control system)

Technical Features

Level switch with one float / displacer is adequate to serve the liquid leakage
Suitable for applications with box pressure up to 10.0 kg/cm2 (g) and box temperature upto 150OC
A decrease in pressure on level indicates either inner Seal or outer Seal has leaked
Circulation is provided with the help of internal circulating device like pumping ring screw.
Nitrogen pressure to be supplied at a pressure of 2.0 kg/cm2 above box pressure
Designed is accordance with ASME Section VIII Division 1 & API 682 Standard
Capacity at normal liquid level = 20 Liters