A single-stage, API overhung centrifugal process pump, either horizontal or vertical inline, incorporates a low-flow auxiliary impeller which receives inlet liquid from the discharge of the primary impeller. This Split Flow feature saves energy by significantly reducing the brake horsepower when the pump is used for two process requirements, with one discharge flowstream at a higher-head (up to twice) and lower-flow (up to 30%) than the other. The pump separates the inlet flow into a primary high-flow, low-head discharge and a secondary lower-flow, higher-head discharge. The pump is effectively two pumps in one, i.e. the primary impeller is selected for the combined flow of both flowstreams and the auxiliary impeller is selected for the flow and additional head of the secondary stream. The Split Flow feature allows the economy of combining two separate pumps into one.

• This modification uses the same pump case, primary impeller and bearing bracket as standard pumps. Only the case cover and shaft are modified to incorporate the auxiliary impeller. The case cover seal chamber remains in compliance with API Standard 682.

Views of a standard pump and the same pump with the Split Flow feature:

Patents Issued.