3 replies to this topic

[sdhir]

Hi

I am starting to learn about centrifugal pumps, I have read lot about minimum flow requirements and the NPSHr, but I am not able to understand what does physically happen during almost no flow conditions in centifugal pumps and why do we need spillback to overcome that?

Thanks
Saurabh

[JoeWong]

Hi

I am starting to learn about centrifugal pumps, I have read lot about minimum flow requirements and the NPSHr, but I am not able to understand what does physically happen during almost no flow conditions in centifugal pumps and why do we need spillback to overcome that?

Thanks
Saurabh

One of the problem is pump cavitation if minimum flow is not maintained.

Read more in :
Cavitation- Wiki
Cavitation- Mcnallyinstitute
Damages by Cavitation
Why Cavitation is Destructive ?
How Pump Cavitation Sound and Looks Like ?
Relationship between NPSHa & NPSHr
How to Detect Pump Cativation ?

[sdhir]

Hi

I am starting to learn about centrifugal pumps, I have read lot about minimum flow requirements and the NPSHr, but I am not able to understand what does physically happen during almost no flow conditions in centifugal pumps and why do we need spillback to overcome that?

Thanks
Saurabh

One of the problem is pump cavitation if minimum flow is not maintained.

Read more in :
Cavitation- Wiki
Cavitation- Mcnallyinstitute
Damages by Cavitation
Why Cavitation is Destructive ?
How Pump Cavitation Sound and Looks Like ?
Relationship between NPSHa & NPSHr
How to Detect Pump Cativation ?

Thanks Joe

Cavitation is one of the problems. Could you please also explain why does the head developed by the pump increases as the flow rate is decreased. I know it can be derived mathematically but it would be great if you could explain the physical phenomena occuring at low flow rates.

[ankur2061]

Saurabh,

Please see my post on minimum safe continuous flow for centrifugal pumps:

http://www.cheresour...art=#entry21110

Regards,
Ankur.