Pump cavitation due to discharge pressure
Pump cavitation due to discharge pressure
(OP)
Hello, I was curious on centrifugal pump cavitation. If there is a discharge valve on the discharge section of the pump that is fully open, why does discharge pressure decrease and why can that cause cavitation in the pump. I understand that if the discharge valve was shut then discharge pressure increases but it stumps me as to why it can decrease when the discharge valve is open.





RE: Pump cavitation due to discharge pressure
Please see the pump performance curve,then you will know the relationship between the Flow and Head.
Heavy-Duty Centrifugal Slurry Pump Manufacturer
www.gempump.com
RE: Pump cavitation due to discharge pressure
RE: Pump cavitation due to discharge pressure
What makes you think the pump is cavitating?
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
RE: Pump cavitation due to discharge pressure
RE: Pump cavitation due to discharge pressure
An impeller that has fallen victim to suction cavitation will lose chunks of material, causing it to look like a sponge.
Typical causes of suction cavitation:
plugged inlet strainer;
blockage in suction pipe (ie. air pocket);
over-running pump on the right side of the pump curve;
incorrect piping design;
inadequate NPSH for the selected pump.
RE: Pump cavitation due to discharge pressure
Think about that logically. If the pressure increases when the valve is shut, then logically, it will decrease when the valve is opened. One is the reverse of the other.
Otherwise, you could close the valve, and get an increase in pressure, then open the valve, the pressure would stay the same, and then you close the valve again, and magically you'd have a higher pressure than the first time you closed it.