How To Read A Pump Curve - Part 2

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One of the most important lines on a pump performance curve is the Net Positive Suction Head (NPSH) curve.  Discreetly applied either below or above the pump performance and efficiency curves, this single plotted line is the key to avoiding cavitation. Required NPSH or NPSHR for a given pump increases with flow.  So, using the pump curve shown in Figure 1, we can see that the NPSHR for this Model 1510 B & G pump with a 8” impeller and 800 GPM and 33 Feet of Total Head is 12 feet of head. 
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How To Read A Pump Curve – Part 1

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If a picture is worth a thousand words then a pump curve must be worth several thousand.

 Make no mistake, there’s a lot of information on a centrifugal pump curve like the one shown here.  It’s no wonder that many newly practicing engineers are a little intimated by them.

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NPSH Demystified: What Is It and Why Is IT So Critical?

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NPSH.  We know what it stands for—Net Positive Suction Head--but do we really know what it means?  Or why it’s so important?  More often than not, explanations of NPSH begin with confusing terminology and (even worse) confusing equations.  That’s not a good starting point.  The concept of NPSH is.
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“What Pressure Do I Pre-charge My Hydropneumatic Tank To?”

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 In our last blog we talked about how to properly size a hydropneumatic tank – but the engineer’s work doesn’t end there.  He or she also needs to specify the appropriate pre-charge on the drawings.  Otherwise the tank will not be set properly at start-up and will not provide the intended energy savings.
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How To Size A Hydropneumatic Tank in A Pressure Booster System

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 Properly sized hydropneumatic tanks are a non-negotiable element in a domestic water pressure booster system--including variable speed systems.  Without a hydropneumatic tank, pumps will short cycle on and off during no flow periods.  Even a leaky faucet can cause pumps to operate unnecessarily without this pressurized reserve of water.    
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