This document discusses API seal flush plans for pumps. Plan 32 uses an external clean fluid source to flush the seal chamber for heat removal, solids removal, and increasing seal chamber pressure. Plan 32 is used for dirty or contaminated fluids, high temperature service, or polymerizing/oxidizing fluids. Preventative maintenance includes using a throat bushing, regulating injection flow and pressure, and ensuring compatibility. Plan 41 flushes the seal from the pump discharge through a cyclone separator and cooler, combining aspects of Plans 21 and 31. Plan 41 is used for high temperature service under 350°F and dirty or contaminated non-polymerizing fluids.

1. 39
API Plan 32
What
• Seal flush from an
external clean source.
Why
• Seal chamber heat
removal.
• Process and solids
removal from seal
chamber.
• Increase seal chamber
pressure and fluid
vapor margin.
Where
• Dirty or contaminated
fluids, paper pulp.
• High temperature
service.
• Polymerizing and/or
oxidizing fluids.

2. 40
API Plan 32 Preventive
Maintenance
• Use throat bushing
sized to hold pressure
or maintain flow
velocity.
• To restrict dirty process
fluid, regulate injection
flow rate.
• To increase fluid vapor
margin, regulate
injection pressure.
• Injection fluid must be
compatible with
process fluid.
• Regularly monitor
control system for
closed valves or signs
of plugging.

3. 41
Plan 41
What
• Seal flush from pump
discharge through
cyclone separator and
cooler.
• Combination of Plan 21
and Plan 31.
Why
• Seal cooling.
• Solids removal from flush
and seal chamber.

4. 42
Plan 41
Where
• High temperature
service, typically less
than 350 ºF (177 ºC).
• Dirty or contaminated
fluids, water with sand or
pipe slag.
• Non-polymerizing fluids.