NPSHRNet Positive Suction Head Required
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It has full indefinite run-dry capability, a 100,000 B10 bearing life and a high efficiency, low NPSHr, impeller design for good suction lift capability.
With the NPSHr data from the pump manufacturer, it would be necessary to then calculate the net positive suction head available (NPSHa) from the cooling system.
NPSHr (NPSH required) is a characteristic of the pump.
Their high NPSHR capabilities keep fluid moving with less chance of cavitation in processes where a suction lift is required or where a high vapor pressure fluid is being pumped.
Second, laminar flow means low NPSHr (net positive suction head required).
For this reason, manufacturers establish the minimum operating flow as well as listing all of the limiting design conditions, such as net positive suction head required (NPSHR), maximum flow and others.
The suction pressure required to prevent cavitation for a particular pump is indicated as NPSHR and is published on the pump curve.
These close coupled pumps are designed on a modular concept, which ensures a wide range of models and therefore an extensive performance range covering capacities from I to 300 m3/hour at heads up to 100 metres, with low NPSHr. CSF CSD pumps are manufactured in electro-polished investment cast AIS!
Most commercial pumps will have an NPSHR curve included on the same graph as the pump design curve.
Efficient motor-speed operation is achieved with new design concepts for the idler and head while retaining excellent NPSHr characteristics.
Large suction inlets lower the NPSHR since velocity head and entrance losses are decreased.