Pump Nozzle Locations

By 7 January 2017

The discharge nozzle of end-suction, single-stage horizontal pumps is usually in a top-vertical position. However, other nozzle positions can be obtained, such as top-horizontal, bottom-horizontal, or bottom-vertical. Figure 14 illustrates the flexibility available in discharge nozzle locations. Sometimes the pump frame, bearing bracket, or baseplate may interfere with the discharge flange, prohibiting a bottom-horizontal or bottom-vertical discharge nozzle position. In other instances, solid casings cannot be rotated for various nozzle positions because the seal chamber connection would become inaccessible.

Practically all double-suction, axially split casing pumps have a side discharge nozzle and either a side- or a bottom-suction nozzle. If the suction nozzle is placed on the side of the pump casing with its axial centerline, the pump is classified as a side-suction pump. If its suction nozzle points vertically downward (see Figure 15), the pump is called a bottom-suction pump. Single-stage, bottom-suction pumps are rarely made in sizes below a 10-in (254 mm) discharge nozzle diameter.

Special nozzle positions can sometimes be provided for double-suction, axially split casing pumps to meet special piping arrangements, such as a radically split casing with bottom suction and top discharge in the same half of the casing. Such special designs are generally costly and should be avoided.