Page 383 - Centrifugal Pumps 2E

348 Centrifugal Pumps: Design and Application

Figure 16-7. Axial thrust on single-suction closed impeller with ribs on back
side,

pumps and stacked (all impellers facing one direction) for difftiser
pumps.

Back-to-back impellers. This arrangement simplifies axial balance for
an odd or even number of stages. In this design there are two locations on
the rotating element that break down half the total pump head. One is the
center bushing between the center back-to-back impellers, and the other
is the throttle bushing in the high-pressure stuffing box. Sleeve diameters
at these locations can be sized to provide axial balance for any number of
stages.