Low NPSH Impellers

Low NPSH Impellers Are Often Key To A Successful Pump Installation

One very important parameter in selecting the right pump for any specific application is the parameter termed Net Positive Suction Head Required or NPSHR.

A discussion on NPSHR vs. NPSHA can be found elsewhere on this site at this location: here: Net Positive Suction Head (NPSH) Margin – National Pump Company

This parameter is often overlooked, resulting in poor performance and premature pump failures. National Pump Company has been expanding its line of low NPSHR impellers for several years now.

Recognizing that NPSHR is measured only at the first stage of a vertical turbine pump, the list of first stage impellers below is matched with the various impellers that can be used for the additional stages

By mixing a low NPSH first stage with a different impeller for the balance of the stages, the pump performance can be enhanced while meeting the NPSHA requirements of an application.

With the use of canned pumps, a pump can be increased in length, with each foot of length equating to a one foot increase in NPSH Available. This adds additional costs to the equipment and to the installation of the equipment. Despite added installation costs, it is always preferred, when NPSHA vs. NPSHR are close or when the “R” exceeds the “A” to lengthen the pump to avoid problems in the future.

National Pump Company and our team of engineers work diligently to improve pump performance, provide the customer with options and to expand our capabilities when needed.