What is the cavitation head of a pump?
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Do all pumps have a net positive suction head? How are the NPSH data for each type of pump applied?
This post was last edited by A Le on 2015-7-16 15:31. Do all pumps have a net positive suction head? Yes, how are the NPSH data for each type of pump applied? The questions are quite general, so I’m not sure how to answer them; they’re too basic. You can try using the forum’s search function. Or take a look at this PPT. If there are any things you don’t understand, let’s discuss them again. http://bbs.hcbbs.com/forum.php?m ... hlight=%C6%FB%CA%B4
In practical applications, when installing the pump, does it suffice to ensure that its installation height is above its net positive suction head?
The installation height has no direct relationship with the net positive suction head. The net positive suction head is divided into NPSHr (required net positive suction head) and NPSHa (available net positive suction head). NPSHa is a parameter specific to the device and is independent of the pump; its value depends on the pump’s installation height – generally, the lower the pump is installed, the higher the NPSHa value. As long as the NPSHa determined by the pump’s installation height is higher than NPSHr by a sufficient margin (usually 0.6 m or 1 m), it is better for the pump’s installation level to be as low as possible.
Is the required net positive suction head for the pump in the diagram a variable value? But some pump selection manuals list only one value – what’s the reason for that?
The figure shows the NPSHr value of the pump, with different values corresponding to different flow rates. The selection manual lists only one value, which corresponds to the rated operating conditions.