What is the NPSH
The NPSH (Net Positive Suction Head) value of a pump is the minimum pressure required at the suction side of the pump to prevent cavitation. Cavitation occurs when the inlet pressure drops too low, causing the liquid to vaporise and potentially damage the pump.
This value is measured in meters (m) and varies with the flow rate of the pump.
Flow Dependency
As the flow rate increases, the NPSH value also increases.
You can find these values on the pump’s performance chart.
Ensuring that the NPSH available in your system is higher than the NPSH required by the pump is crucial for maintaining efficient and safe pump operation.
Difference Between Available NPSH and Required NPSH
Net Positive Suction Head (NPSH) is a critical parameter in pump systems to avoid cavitation. There are two types of NPSH: Available NPSH (NPSHa) and Required NPSH (NPSHr).
Available NPSH (NPSHa) is the absolute pressure available at the pump suction port.
It depending on the system that feeds the pump as well as a number of other factors such as the fluid temperature, atmospheric pressure, and the static head of the fluid, the fluid density or viscosity…
Required NPSH (NPSHr), on the other hand, is the minimum pressure needed at the pump suction to prevent cavitation, as specified by the pump manufacturer.
It is determined by the pump design and is usually provided on the pump’s performance curve.
Find out how to read pump curves here.
For optimal operation, the NPSHa must always be greater than the NPSHr to ensure that the pump operates without cavitation, thereby maintaining efficiency and preventing damage.
SPS Pumps is at your Disposal
SPS Pumps is the ideal partner for industry. We offer unrivalled technical support and in-depth knowledge of centrifugal pumps, as well as other types of pump.
Our expertise guarantees you reliable and efficient solutions tailored to your needs.
We also have a very wide range of spare parts in stock.
With SPS Pumps, you have a trusted partner committed to optimising your fluid handling systems.
Call us at +32 2 657 23 53 or send us an e-mail at info@sps-pumps.com.
The content of this webpage is inspired by and sourced from the Grundfos Pump Handbook.
