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The Practical Pumping Handbook .............................................. i .................................... i-i-

From this equation, the actual shaft deflection (y) can be calculated at
the point on the shaft measured at dimension 'x' from the impeller
centerline. This point represents the operational location of the seal
faces which is generally considered to be at the face of the stuffing box.
At this point many industry standards require the deflection of the shaft
to be no more than 0.002 inches (0.5 mm).
Owing to the potential of these high unbalanced hydraulic influences,
the capability of the pump shaft to handle such loads without excessive
deflection becomes very important. Troubleshooting details of such a
condition can be found in Chapter 11.4.2.2, using the simplified
version referred to as the Slenderness Ratio.

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