PC Pump Cavitiation 3

[Milkboy]

Can a Progressive Cavity Pump Cavitate?

What damage would see if so?


I have experience with Centrif pump and cavitation
but not with PCs
In Centrif you see pitting on the impeller and maybe
tell tale signes in the Mech Seal.

What do you see in PCs

Any advice / Links etc appreciated


Ryan

-
Milkboy

 

[codeeng]

A PC pump can still cause cavitation although typical NPSHR values are generally lower than a centrifugal pump. Also, cavitation damage is usually less due to the slower speeds. You should consult with your PC supplier to optimize your suction hydraulics.

 

[DesignerMike]

Most PC pumps have an enlarged inlet (that I have used anyway) to accomodate a thicker product. High viscosity product will significantly affect the NPSHR (I'm sure you know this).

I agree with codeeng that the pump manufacturer will be able to tell you what is happening. They will want the viscosity, and inlet piping conditions to give you a better idea. It is REALLY hard to suck peanutbutter through a 1/4" inlet. (had a customer tell me my pump didn't work last week), but a 1 1/2" hose worked a lot better.

 

[stanier]

When determining the NPSHA for a positive pump one has also to take into account the accelration losses . Refer Miller The Reciprocating Pump