7 replies to this topic

[panoska]

Hello everyone,

 

I was reading some articles and I got confused with the following:

 

Does the pump curve shows discharge head or differential head?

 

(Differential head: Head discharge - Head suction)

 

 

[breizh]

hi,

difference between discharge and suction head = Hd -Hs 

https://www.rotechpu...trifugal-pumps/

Breizh

[fallah]

Hello everyone,

 

I was reading some articles and I got confused with the following:

 

Does the pump curve shows discharge head or differential head?

 

(Differential head: Head discharge - Head suction)

 

Differential Head

[breizh]

Hi,

another resource

Breizh

Attached Files

•  understanding centrifugal pump.pdf   434.73KB   20 downloads

[panoska]

Thanks both, I had the same knowledge that it is the differential head. But, I read somewhere that the discharge pressure/head of the pump you can use it directly in the pump curve. I will try to find the source and I will attach it here! 

[breizh]

Hi,

Yes, probably at zero flow, which indicates the shut off pressure and confirm the right pump curve choice, if needed.

Breizh 

[panoska]

Hi,

 

It was not referring to the shut-off. 

[TheChemEng]

Using the discharge pressure of a pump can provide an 'indicative' idea of where it is operating on its performance curve. A couple of points to note: technically, a pump curve plots "head" on the y-axis (in relation to you first question). Therefore, the discharge pressure is related to the density of the fluid being pumped. You also need to account for both the suction static pressure and the suction losses.

For example, if you measure 2 barg on the pump discharge while pumping methanol, this corresponds to a head of approximately 25 metres. If the methanol tank feeding the pump has a liquid level 2 metres above the pump and there are minimal suction losses, the differential head would be around 23 metres.

Edited by TheChemEng, 28 November 2024 - 05:21 PM.