Pump Balance line cavitation ? 2

[Heed]

Hi,

An offshore turbine driven water injection pump has been taken offline. On inspection, some internal damage was noticed in the balance line. Some within the organisation have stated this damage could be erosion due to fine filter failure or corrosion and one has stated cavitation ? I've never heard of cavitation in a balance line. Has anyone on this forum experienced this ?

 

[JJPellin]

Cavitation occurs when pressure drops low enough for vapor bubbles to form and then increases enough for the vapor bubbles to collapse. A typical balance line would not have the required pressure increase. There could be one explanation for how cavitation could occur. If there was a flow measurement in the balance line, the localized high velocity through the flow meter could allow for bubble formation. And, the reduction in velocity on the other side of the flow meter could allow for bubble collapse. But, this is all speculation. A drawing of the pump showing the location of the damage would help.

I have never, personally seen cavitation damage in the balance line of any pump.


Johnny Pellin