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Centrifugal Pumps Design and Application 2nd ed - Val S. Lobanoff, Robert R. Ross (Butterworth-Heinemann, 1992)

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Vertical <strong>Pumps</strong> 121<br />

Figure 9-8. Barrel-mount<strong>ed</strong> pump (courtesy BW/IP International, Inc. Pump Division,<br />

manufacturer of Byron Jackson/Unit<strong>ed</strong> <strong>Pumps</strong>).<br />

pense. Often a special first-stage impeller with superior NPSH characteristics<br />

is furnish<strong>ed</strong>. Otherwise, the bowl assembly is of a multi-stage design<br />

with identical impellers of the radial or semi-radial flow type. The<br />

bowl assembly is either directly suspend<strong>ed</strong> from the discharge head or<br />

connect<strong>ed</strong> to the head with a discharge spool, the length of which is determin<strong>ed</strong><br />

by the NPSH requir<strong>ed</strong>.<br />

The configuration shown in Figure 9-9 is of the pull-out type that permits<br />

removal of the pump without disturbing either the discharge or suction<br />

nozzle connections. Pump alignment is, within reason, not affect<strong>ed</strong><br />

by any nozzle forces impos<strong>ed</strong>. The suction nozzle can be locat<strong>ed</strong> either in<br />

the suction barrel or in the discharge head, in line with the discharge nozzle.<br />

The latter "in-line" construction is commonly us<strong>ed</strong> for booster applications<br />

in pipelines. The shaft sealing device in the discharge head is usu-

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