net positive suction head

Questions are answered about monitoring power consumption and noise level parameters for pumps.
The concept of “suction energy” was developed to enhance the evaluation of the NPSH characteristics of centrifugal pumps, but I fear that it misses the mark.
For the non-expert in pump technology, selecting the most appropriate pump technology for a specific application or process system can be challenging because.
A rotary, positive displacement, three-screw pump technology was chosen for the main fuel oil injection pump, based on years of proven success in distillate fuel oil applications worldwide.
Packaged pump systems are gaining popularity due to their space saving design, simplified installation, single source responsibility and advanced control options with communication ability.
The NPSH curve is roughly a lazy "U," reaching a minimum value at a capacity Q about 40 percent of the best‑efficiency capacity.
A refinery's vertical pump passes the test, verifying its performance before installation.
If pump cavitation is not detected and quickly eliminated, significant damage can occur to the impeller and other internal components. Since cavitation (the formation and collapse of vapor bubbles in the pumped fluid as it passes through the pump impeller) is often temporary or even induced by the process, timely knowledge of the condition is extremely important so operators can act to alleviate the problem and prevent damage.
Digitization methods are critical when using pump selection software.
I have seen, and I am sure you have too, countless examples of installed pumps that are poor hydraulic fits. These selection mistakes are called off-design pump selections, bad actors, misapplied pumps, etc.
Due to high specific gravity, viscosity and particle size of mining materials, centrifugal pumps are continuously challenged in mining applications.
The International Paper plant in Courtland, Ala., had experienced problems with a white water pump on a paper machine since the plant installed the pump in the late 1970s.
Last month I reviewed an Excel-based Radial Thrust Calculator and showed how it can predict the magnitude of unbalanced radial thrust when a centrifugal pump is operated to the left of BEP.
Our attempts to normalize or classify water turbine hydraulic performance culminated in 1915 with the development of the specific speed concept, which was later applied to centrifugal pumps.
A number of technical papers (1, 4, 7, 8) have shown that the maximum damage rate to centrifugal pumps, at least in water services, typically occurs when the NPSHA is in the range of two to three times the NPSHR3.
In 1982, Richard Dubner of Chevron developed a graph for use in establishing minimum continuous flow rates for centrifugal pumps.
If it is necessary to increase a system's NPSHA, one or more of the following steps may be employed.NPSH, net positive suction head, pump system optimization
The impact of pump wear ring clearance on pump efficiency.
Thorough analysis, testing and upgrades renew the life of an old single-stage, double-suction, horizontal split-case pump.
It is common practice for the designer of a new centrifugal pump to model the new pump from an existing pump. Each dimension of the existing pump (except the shaft diameter) is multiplied by a modeling factor "F" to obtain each dimension of the new pump.
The Hydraulic Institute NPSHA Margin Work Group (1) recommended NPSH margins ranging from zero to four times the NPSHR (NPSHA÷NPSHR = 1 to 5).
Sometimes running pumps faster can help avoid cavitation.

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