Jump to content



Featured Articles

Check out the latest featured articles.

File Library

Check out the latest downloads available in the File Library.

New Article

Product Viscosity vs. Shear

Featured File

Vertical Tank Selection

New Blog Entry

Low Flow in Pipes- posted in Ankur's blog

Pump Discharge Pressure


This topic has been archived. This means that you cannot reply to this topic.
7 replies to this topic
Share this topic:
| More

#1 anwar_ali040

anwar_ali040

    Brand New Member

  • Members
  • 5 posts

Posted 30 September 2014 - 01:24 PM

For two pumps operating in parallel, with discharge pipe of 365 mm, connected to a header of 599 mm dia. Is it possible to have header pressure greater than pump discharge pressure.... please elaborate using relations 



#2 fallah

fallah

    Gold Member

  • ChE Plus Subscriber
  • 4,930 posts

Posted 30 September 2014 - 02:00 PM

Hi,

 

If two identical parallel pumps are working at the same time, the header pressure would be a little bit lower than the discharge pressure of the each pump...



#3 himant

himant

    Gold Member

  • Members
  • 53 posts

Posted 30 September 2014 - 09:50 PM

calibrate your PG/PT... they always confuse you with their values. Even I got confused once in similar case!



#4 breizh

breizh

    Gold Member

  • Admin
  • 6,292 posts

Posted 30 September 2014 - 11:44 PM


Hi ,

I think you got the answers . The relation you may refer to is the application of Bernoulli Theorem between discharge point and header .

Breizh

#5 Ajay S. Satpute

Ajay S. Satpute

    Gold Member

  • Members
  • 177 posts

Posted 01 October 2014 - 05:59 AM

Anwar,

 

Do you mean that, both the pumps are running (flow is doubled) and discharge pressure shown by PG is more than that of as per pump curve?

 

Please refer below links.

http://www.mcnallyin...-html/15-01.htm

http://www.engineeri...rial-d_636.html

https://www1.eere.en.../pdfs/38945.pdf

 

In parallel (or series) or not, pumps will follow pump curve.

 

 

Regards.

 

Ajay S. Satpute



#6 katmar

katmar

    Gold Member

  • ChE Plus Subscriber
  • 663 posts

Posted 01 October 2014 - 02:51 PM

I agree with Breizh that the Bernoulli Theorem needs to be considered.  Because I am feeling lazy I will refer you to a reply I gave recently to a similar question rather than writing it all out again.  See http://www.eng-tips.....cfm?qid=371053

 

The difference in your case is that it seems that the two pumps are running simulateously so the volumetric flow rate in the header is twice what it is in each pump discharge.  The header has an area of 2.7x the area of each of the pump discharges so the increase in flow rate and the increase in area almost cancel each other out.  Depending on how the discharge pipes are connected into the header (eg, stub-in connections, pipe reducers, tapered reducers) and the losses incurred there,  the pressure in the header could be slightly higher or lower than in the discharge pipes.



#7 anwar_ali040

anwar_ali040

    Brand New Member

  • Members
  • 5 posts

Posted 02 October 2014 - 12:53 PM

Actually in my case its a little higher.... Anyway thnx all 4 ur help...

#8 DB Shah

DB Shah

    Gold Member

  • ChE Plus Subscriber
  • 155 posts

Posted 03 October 2014 - 12:30 AM

Is your header underground and the pressure is measured in a under ground pit? In that case there will gain of elevation and if the friction losses are negligible the header might show pressure higher compared to pressure immediate at discharge.

 

And hence, as Breiz stated "-Bernoulli Theorem between discharge point and header."






Similar Topics