API Plan 12


Product recirculation from pump discharge through a Y strainer and a flow control orifice to seal chamber.


1. Becomes a self-venting plan for horizontal pumps.

2. Can handle dirty liquids to some extent.


1. In general used in slightly dirty and non-polymerizing fluids.


1. Always ensure that orifice is placed after the Y strainer.

2. This plan is normally discouraged due to unreliability of Y strainer.

3. Calculation of recirculation is required.



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