What is Cavitation Margin? What is Suction Range?

When the pump is working, the liquid will generate vapor at the inlet of the impeller due to a certain vacuum pressure. The vaporized bubbles will erode the impeller and other metal surfaces under the impact movement of the liquid particles, thereby destroying the impeller and other metals. At this time, the vacuum pressure is called vaporization pressure. Cavitation margin refers to the excess energy that exceeds the vaporization pressure per unit weight of liquid at the pump suction port. The unit is marked in meters and (NPSH)r is used.

The suction range is the necessary NPSH Δh: the vacuum degree of the pump allowed to suck liquid, that is, the installation height allowed by the pump.

Suction range = standard atmospheric pressure (10.33 meters)-cavitation margin-safety amount (0.5 meters)

The vacuum height of the standard atmospheric pressure energy pressure pipeline is 10.33 meters.

For example: a pump must have a cavitation margin of 4.0 meters, what is the suction range Δh?

Answer: Δh=10.33-4.0-0.5=5.83 meters

If you want to learn more news about centrifugal water pumps, please read these blog posts.

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