The design is the visual features of the Pump Inlet Flow Strainer shown in the drawings. In the drawings:Figure 1 is a top side perspective view of the Pump Inlet Flow Strainer;Figure 2 is a top plan view thereof;Figure 3 is a side elevation view thereof;Figure 4 is an underside perspective view thereof; andFigure 5 is an underside plan view.Drawing(s)/photograph(s) of the design is (are) included.