API Plans

Plan 01 & Plan 11

Description: Plan 01 is an

integral recirculation from

the pump discharge to the

seal chamber. This is an internal version of Plan

11. Recommended for clean process only.

Advantages: No exposed

plumbing around pump.

Reduces risk of freezing or

polymerization of process.

Not recommended for

vertical pumps.

Description: Plan 11 is recirculation from pump discharge

through an 1/8” minimumflow control orifice (when necessary),

to the seal and back into the process through the pump seal


Objective: Dissipate seal generated heat, vent the seal chamber

at start‐up and increase the vapor margin in the seal chamber.

Advantages: When used with a close‐clearance throat bushing,

will raise the pressure in the seal chamber to maintain the

process in the liquid state when cooling is not

practical. Best for a clean, non‐polymerizing process.