Net Positive Suction Head (NPSH) is perhaps the most misunderstood concept in pumping technology. The main source of confusion stems from multiple uses of the term in different but related contexts. One usage of the term NPSH is to denote the suction performance characteristic of the pump itself, independent of the system into which it […]
Multi-stage pump in-line (tandem) versus opposed impeller arrangements
Common to early twentieth century multi-stage rotodynamic (centrifugal) pumps were design features for minimizing axial thrust. At that time the thrust bearings available had limited load carrying capability. Design solutions evolved in two principal directions. One design approach was to hydraulically balance the thrust for each stage or for the entire series of in-line (tandem) […]
The ideal pump
Consider a pump that functions reliably under all possible operating conditions, no matter how abusive, including complete loss of prime or dead heading. Imagine this pump converts all of its mechanical work input into useful liquid energy output. Next, the seal or seals are zero leakage and require no flush, quench, or support system. The […]
Storm drain – what happens when the power goes out
During heavy rains earlier this week a City of Long Beach storm water drainage pump was temporarily inoperable due to a power outage. This occurred during a peak storm period and is at least partly to blame for flooding in the area. A similar event at the same location is said to have occurred before. […]